This invention relates to an image forming method by which characters,
figured patterns, pictures or the like are recorded on recording mediums having
a plate, sheet or foil made of aluminum or aluminum alloy (hereinafter often simply
"aluminum sheet"), as exemplified by nameplates, display boards, construction
wall materials, automobile panels and parts, tableware, aluminum cans and interior
decorative panels. It also relates to a process for producing a decorative aluminum
plate, and an apparatus used for carrying out such a process.
Related Background Art
As recording mediums for ink-jet recording, paper is in general use.
Those made of other than paper are limited to plastic films provided on at least
one side thereof a layer endowed with ink absorption properties by a special treatment.
This is considered due to the fact that ink-jet recording apparatus have been
mainly used for office work and hence records are mostly made on paper serving
as an information medium and also that recording mediums are required to have
ink absorption properties and fixing properties on account of the ink-jet recording
system in which ink droplets are caused to fly and adhere to recording mediums.
Under such circumstances, as ink-jet recording apparatus are made
to have a higher speed and a higher function, the application of ink-jet recording
to recording mediums made of materials other than paper or plastic film is attracting
notice. In particular, ink-jet recording on metallic materials such as aluminum
or alloys thereof is expected not only to make it possible to provide a simpler
recording process applicable on metallic materials, which can substitute printing
or the like, but also to promote the expansion of use of articles made of metallic
materials and on which characters, patterns, pictures or the like have been recorded.
Metallic materials utilized in a variety of fields and uses may include
aluminum and alloys thereof. In particular, aluminum materials on the surfaces
of which anodic oxide layers, what is called aluminum anodic oxide layers, are
formed to improve the corrosion resistance, surface strength and decorativeness
of aluminum have been hitherto used in construction materials, tableware, panels
for electronic machinery, etc., and also in radiator panels or the like utilizing
good heat dissipation properties of such layers. In particular, because the aluminum
anodic oxide layers can be colored with ease, members having aluminum anodic oxide
layers are also used as decorated wallboard materials or door members, as well
as artistic decorations themselves. They are also in wide use as personal nameplates
of various types.
As methods for coloring or recording on aluminum anodic oxide layers
(or anodic oxide layers), photographic printing is in general use. In this method,
a series of steps of coating a resist, exposing, developing, dipping in a recording
solution (dye solution) with a given color and stripping the resist are repeated
for each color to form a color image by the use of multi-color recording solutions.
The photographic printing conventionally used in the recording on
the materials made of aluminum or alloys thereof on which anodic oxide layers have
been formed requires a large number of processing steps, which is complicated
and takes a long time, and hence the number of steps and the processing time greatly
increases with an increase in the number of colors of the recording solutions.
Thus, there is a limit to the processing of a large quantity of materials.
Now, the ink-jet recording that enables color recording at a high
speed may be applied to such processing. This makes it possible to greatly shorten
the processing time and more improve the productivity, and also makes it unnecessary
to use developing solutions, washing solutions and so forth necessary for the
photographic printing, so that a great cost reduction can be achieved. This also
can solve the problems of environmental pollution caused by, or disposal of, waste
liquors such as developing solutions and washing solutions after their use.
The application of ink-jet recording to aluminum anodic oxide layers
is disclosed, for example, in Japanese Patent Applications Laid-open No. 62-115074
and No. 3-147883. The methods disclosed in these publications, however, are nothing
but those in which the conventional ink-jet recording is directly applied to sheet
materials having aluminum anodic oxide layers.
In the ink-jet recording, ink wettability, ink absorption properties
and ink fixing properties of recording mediums are especially important. If the
recording mediums have poor fixing properties, ink droplets first shot for recording
and ink droplets subsequently shot for recording may mix to cause color mixture
to give no desired color reproduction and sharpness. If the recording mediums have
a poor wettability on their surfaces, the ink may be repelled on the surfaces,
so that no good images can be obtained.
However, the aluminum anodic oxide layers as stated above are not
necessarily satisfactory in respect of the ink wettability, ink absorption properties
and ink fixing properties. Hence, the mere direct application of ink-jet recording
to aluminum anodic oxide layers causes the following problems, and can not necessarily
be said to be practical.
The ink imparted to aluminum anodic oxide layers is little absorbed
in the anodic oxide layer, and ink droplets mutually cause color mixture on its
surface, resulting in a blurred image. The aluminum anodic oxide layers also have
so poor ink fixing properties that various rollers pertaining to the transport
of recording mediums and the control of recording position in the ink-jet recording
apparatus may come in touch with the areas in which the ink has not been fixed,
and hence any marks of a roller rub may appear on the surface to damage recorded
Meanwhile, ink-jet recording carried out using as an ink component
a hitherto well known dye for anodized aluminum also has the disadvantage that
the surfaces of aluminum anodic oxide layers can not be well colored and no satisfactory
colors can be obtained especially in the case of deep colors.
In addition, usual ink-jet recording, in which a recording head having
a number of nozzles carries out simultaneous recording in order to increase printing
speed, has another disadvantage that, when lines are recorded in an unfixed state,
the ink of a line first drawn is pulled toward the ink of a line subsequently
drawn, to cause a higher density at some part for each line, that is, to cause
Thus, it can not be said to be practical that the high-speed color
recording carried out by ink-jet recording is directly applied to the recording
mediums made of materials other than paper or the like conventionally used, e.g.,
those made of metals having aluminum anodic oxide layers.
Meanwhile, ink-jet recording apparatus used for can manufacturing
and for lot-number printing have been put into practical use. Most of them, however,
make use of oil-based inks or pigment type inks, and can not fly ink droplets
having diameter small enough to form highly minute images or tend to cause clogging
when nozzles are arranged in a high density. Thus, the fields to which they can
be applied are limited, and they can not be said to be practical for the recording
of more highly minute images. Moreover, in the ink-jet recording apparatus used
for such purposes, their nozzles can not have a sufficient work precision and
can only have a nozzle density of several nozzles/mm at best. Hence, it has been
difficult to form more highly minute images and there has been a problem in the
image quality when applied to decorative purpose. Thus, it also can not be said
to be practical that the ink-jet recording used in this field is applied to the
recording on aluminum anodic oxide layers.
As discussed above, the mere application of conventional ink-jet
recording to the aluminum anodic oxide layers of aluminum or alloys thereof has
brought about the following problems.
SUMMARY OF THE INVENTION
- 1) Mixing between colors (i.e, bleeding) may occur to cause blurred images.
- 2) Uneven lines may occur in the recording scans of recording heads.
- 3) Unfixed ink is transferred to transport rollers and so forth inside the
apparatus to cause ghost images and crushed images.
- 4) Color ink has so poor a coloring ability to the aluminum anodic oxide layers
that rinsing after printing may cause a decrease in image density, resulting in
a low density.
The present invention has been made taking account of these problems,
and intends to provide an image forming process, a process for producing a decorative
aluminum sheet and an apparatus for its production that are necessary for a technique
in which an ink-jet recording system is employed to form on anodic oxide layers,
images having a superior image performance, e.g., free of color mixture, uneven
scans and crushed images and having a sufficient color density.
Accordingly, the present invention provides an image forming process
as defined in claims 1 and 25, a process for producing a decorative aluminum plate,
sheet or foil as defined in claims 10 and 38, and an apparatus for producing a
decorative aluminum plate, sheet or foil as defined in claim 19.
The image forming process for producing a decorative aluminum plate,
sheet or foil according to the present invention that can achieve the above objects
is an ink-jet recording process for forming a recorded image by imparting ink containing
a dye and a volatile component from a recording head having a plurality of ink
ejection orifices to an anodic oxide layer formed on the surface of a plate, sheet
or foil made of aluminum or an aluminum alloy, the process comprising;
- a first step of dehydrating and activating the anodic oxide layer by means
- a second step of imparting ink to the anodic oxide layer having been subjected
to heat treatment; and
- a third step of removing the volatile component from the ink to fix the dye
contained in the ink into the anodic oxide layer.
In the process of the present invention, multi-color inks are preferably
used as the ink so that a colored recorded image can be formed. In the process
of the present invention, each treatment applied to the anodic oxide layer in
at least one of the first step and the third step is carried out by a treatment
selected from a treatment of heating the layer, a treatment by electromagnetic
induction and a treatment by dry-air spraying. Two or more treatments of these
may be used in combination. The third step may also comprise a treatment by rinsing
In the process of the present invention, the second step may preferably
be carried out by bubble jet recording system.
As for the apparatus for producing a decorative aluminum plate, sheet
or foil according to the present invention, it is an apparatus for forming a recorded
image on a recording medium having an anodic oxide layer formed on the surface
of a plate, sheet or foil made of aluminum or an aluminum alloy, by imparting
ink droplets of at least one color to the anodic oxide layer formed thereon, the
- (a) a first means for heating to dehydrate and activate the anodic oxide layer;
- (b) a recording head having a plurality of ink ejection orifices from which
the ink is applied to the anodic oxide layer in accordance with image recording
signals, wherein the ink comprises a dye and a volatile component;
- (c) a second means for heating the aluminum plate, sheet or foil to remove
the volatile component from the ink applied and fix the dye contained in the ink
in the anodic oxide layer; and
- (d) a third means for transporting the aluminum plate, sheet or foil from the
first means to the second means.
The apparatus of the present invention may preferably further comprise
a means (d) for transporting the recording medium under heat insulation. The apparatus
may also preferably further comprise a means (e) for detecting the temperature
of the recording medium, a means (f) for controlling at least one operation of
the means (a) and (c) in accordance with the information on the temperature, obtained
in the temperature detecting means (e), or a means (g) for controlling the transport
of the recording head (b) in its primary scanning direction and secondary scanning
direction in accordance with the information sent from the temperature detecting
means (e), or may preferably further comprise all of these means (e), (f) and
BRIEF DESCRIPTION OF THE DRAWINGS
DESCRIPTION OF THE PREFERRED EMBODIMENTS
- Fig. 1 diagrammatically illustrates the structure of an anodic oxide layer
of aluminum or an alloy thereof.
- Figs. 2A to 2C and 2D to 2F each illustrate the surface configuration of an
aluminum or aluminum alloy material and how bleeding occurs or does not occur.
- Fig. 3 illustrates a manner of the storage of a recording medium on which the
anodic oxide layer has been formed.
- Fig. 4 also illustrates a manner of the storage of a recording medium on which
the anodic oxide layer has been formed.
- Fig. 5 still also illustrates a manner of the storage of a recording medium
on which the anodic oxide layer has been formed.
- Fig. 6 is a graph to show the state of evaporation of a solvent commonly used
in ink-jet recording inks.
- Fig. 7 diagrammatically illustrates the main part of an example of the ink-jet
recording apparatus of the present invention.
- Fig. 8 illustrates an example of the construction of a tray used in the ink-jet
recording apparatus of the present invention.
- Fig. 9 illustrates an example of a position correcting system operable in accordance
with the temperature of the image forming surface of a recording medium when the
recording medium and a recording head are positionally registered in the ink-jet
recording apparatus of the present invention.
- Fig. 10 illustrates a specific example of the formation of dots on a recording
medium in the ink-jet recording of the present invention.
- Figs. 11A to 11D illustrate specific examples in which patterns are changed
in 1st-pass to 4th-pass, respectively, for a black color to make a record in the
ink-jet color recording of the present invention.
- Figs. 11E to 11H illustrate specific examples in which patterns are changed
in 1st-pass to 4th-pass, respectively, for a cyan color to make a record in the
ink-jet color recording of the present invention.
- Figs. 12A to 12D also illustrate specific examples in which patterns are changed
in 1st-pass to 4th-pass, respectively, for a magenta color to make a record in
the ink-jet color recording of the present invention.
- Figs. 12E to 12H illustrate specific examples in which patterns are changed
in 1st-pass to 4th-pass, respectively, for an yellow color to make a record in
the ink-jet color recording of the present invention.
- Fig. 13 perspectively illustrates an example of an apparatus for carrying out
the ink-jet color recording of the present invention.
- Figs. 14A and 14B illustrate an ideal state of image formation on a recording
- Figs. 15A and 15B illustrate an improper state of image formation on a recording
- Figs. 16A to 16G illustrate how dots come together after their impact onto
a recording medium.
- Figs. 17A and 17D illustrate how dots run over after their impact onto a recording
- Figs. 18A to 18L illustrate a manner by which an image is formed on a recording
medium according to the present invention.
- Figs. 19A to 19F also illustrate a manner by which an image is formed on a
recording medium according to the present invention.
- Fig. 20 illustrates a dot-interval drive according to the present invention.
The recording medium used according to the present invention comprises
an anodic oxide layer formed on the surface of a plate, sheet or foil made of aluminum
or an alloy thereof. The recording medium may also have a laminated structure
in which the plate, sheet or foil made of aluminum or an alloy thereof is provided
on a base comprised of a material other than aluminum or an alloy thereof, including
various materials (substrate materials) as exemplified by a clad material.
Regarding the aluminum or an alloy thereof used in the present invention,
there are no particular limitations thereon so long as they are well capable of
forming the anodic oxide layer. For example, it is possible to use sheet or foil
materials of a pure aluminum type such as those prescribed in JIS-1050 and sheet
or foil materials made of an aluminum alloy used for anodized aluminum, such as
an alloy containing Mg.
The surface of the plate, sheet or foil made of aluminum or an alloy
thereof which is a material worked in desired shape and size by means of a press
machine or the like so as not to cause any unauthorized deformation such as warpage
or flashes and on which the anodic oxide layer is formed to provide an image forming
surface, may preferably be treated, if necessary, by a mechanical means or chemical
polishing to control its surface properties so that good images can be formed in
the course of recording. This surface treatment can be exemplified by a treatment
of providing concavities smaller than ink droplets and having ridges along their
peripheries, over the whole image forming surface. Such a surface treatment makes
it possible to prevent ink, having impacted on a desired position, from mixing
with ink having impacted on other regions or moving to other regions to cause bleeding.
In particular, since aluminum sheet materials commonly available are rolled materials,
marks (grooves) of rolling extend in one direction, and the ink tends to run along
the marks of rolling, so that inks tend to cause color mixture in the direction
of rolling. Accordingly, the concavities with a diameter smaller than the ink
droplets are formed over the whole surface, whereby such color mixture can be prevented.
The diameter of a concavity may be set in accordance with the diameter of an ink
droplet. For example, ink droplets each have a diameter of about 100 µm under
recording conditions of 360 dpi, and hence any surface treatment method that can
make a concavity having a diameter of smaller than 100 µm may be selected and
used. Figs. 2A through 2C, along stages Figs. 2A to Fig. 2C thereof, diagrammatically
illustrate a mechanism by which the bleeding can be prevented on the surface provided
with such concavities. Figs. 2D through 2F, along stages Fig. 2D to Fig. 2F thereof,
diagrammatically illustrate typical examples in which the bleeding occurs. In
Figs. 2A and 2D, reference numeral 21 denotes ink droplets; 22, an anodic oxide
layer; and 23, an aluminum plate.
This surface treatment can be made using a mechanical working process
in which a beads type abrasive is sprayed on the surface, e.g., shot blasting,
or a chemical process making use of an etching solution. The treatment may preferably
be made by chemical polishing that can effectively form concavities having ridges
around their peripheries on account of the generation of gas and the presence of
grain boundaries at the time when the recording medium is immersed in an etching
The surface of the material on which the anodic oxide layer is to
be formed is further optionally subjected to degreasing and pickling that are
commonly carried out, and thereafter the anodic oxide layer is formed by anodizing
in, for example, a sulfuric acid bath, followed by rinsing with water. The anodic
oxide layer is formed in a layer thickness of, for example, from 5 to 25 µm.
Fig. 1 diagrammatically illustrates the structure of an anodic oxide
layer of aluminum or an alloy thereof. An anodic oxide layer 1 formed on the surface
of a base 4 comprised of aluminum or an alloy thereof is constituted of a large
number of cells 3, and a pore (a minute opening) 2 is formed substantially at
the center of each cell. The bottom of this pore 2 is constituted of a barrier
layer 5 located at the boundary between the pore and the base 4.
Accordingly, the larger diameter the pore has, the higher the coloring
ability and ink receptivity become. Also, the deeper the pore is, the higher the
ink receptivity becomes. Hence, as conditions for electrolysis in the anodizing,
it is preferable to select conditions under which pores can be formed in such
The diameter or depth of the pore 2 can be increased by a treatment
made at a higher temperature or using an electrolytic solution with a higher density.
If, however, the thickness of the barrier layer 5 becomes smaller, the material
may cause a decrease in its own corrosion resistance. Hence, the conditions for
electrolysis should be selected taking account of these factors.
For example, as the compostion of the electrolytic solution, a solution
of 10 to 30% (weight ratio) of sulfuric acid is prepared. A SUS (a kind of stainless
steels) plate is used as the cathode, and an aluminum sheet having been subjected
to the pretreatment described above and also subjected to degreasing, rinsing
with water and desmutting before the anodizing is set on the anode. In an electrolytic
bath controlled to have a bath temperature of about 25°C and also well agitated,
the anodizing is carried out at a current density of from 60 to 300 mA/m2
for a suitable time until the required layer thickness is achieved. Thereafter,
the treated product is taken out of the electrolytic bath, thoroughly rinsed with
water, dried, and then stored.
The above electrolysis may be divided into two stages, where conditions
under which large-sized pores are formed are employed in the first stage and conditions
under which small-sized pores are formed are employed in the second stage so that
the barrier layer can be made to grow on the substrate side to improve corrosion
resistance. Such a method is also effective. In this case, the treatment at the
second stage may be carried out in the same bath as that for the first stage,
or may be carried out in a bath different from that for the fist stage. In order
to grow the barrier layer, it is also effective to use a boric acid type electrolytic
In this way, the image forming surface comprised of the anodic oxide
layer is formed on the surface of the base comprising the plate, sheet or foil
of aluminum or an alloy thereof. The recording medium thus obtained is stored if
necessary, and thereafter treated in the first step of ink-jet recording carried
out in the image forming method of the present invention.
When the recording medium is stored, the state of its storage may
greatly influence the operation of image formation and the state of storage should
preferably be controlled so as to be suited for the desired end. As described
in relation to Fig. 1, the anodic oxide layer is constituted of a number of cells
having pores, and the presence of these pores makes it possible for the ink to
be absorbed into the layer to make a record. If, however, the anodic oxide layer
is left to stand in an atmosphere containing water (vapor) and oxygen as in the
air, a hydroxide is formed on the layer as a result of the reaction of water with
oxygen. If it is formed in the pores, the pores becomes narrow or may be closed.
As the reaction proceeds, almost all the pores in the layer are brought into the
state of being closed. A decrease in pore volume or the closure of pores results
in a decrease in ink receptivity (ink absorption), and brings about the problem
that the image quality tends to deteriorate because of occurrence of bleeding
and color mixture. Hence, in the storage of the recording medium, it is preferable
to shut off water content and oxygen. As a manner of storing the recording medium,
the recording medium may preferably be stored in a container into which nitrogen
gas can be flowed to form an atmosphere of nitrogen gas, be stored in a container
into which a moistureproofing agent such as silica gel or a deoxidizing agent
can be put to form an atmosphere of dry air, or be kept away or shut off from the
Examples of the manner of storage are shown in Figs. 3 to 5. Fig.
3 shows a storage box 32 provided with a nitrogen gas blow pipe (an N2
blow pipe) 33, where the inside of the box is replaced by nitrogen so that the
recording medium 31 can be stored. Fig. 4 shows a bag 34 made of resin, in which
a deoxidizing agent 35 is put together with the recording medium 31 for its storage
under a sealed state. The manner of storage shown in Fig. 5 is a manner in which
the surface of an anodic oxide layer 31-1 formed on a base 31-2 comprised of aluminum
or an alloy thereof is covered with an adhesive tape 36 comprised of an oxygen
and vapor barrier film 36-1 such as polyethylene terephthalate film and an adhesive
layer 36-2 formed on its surface to hermetically seal the former so that the recording
medium can be stored in the state it is kept away from its contact with the atmosphere.
In the first step of the ink-jet recording of the present invention,
the anodic oxide layer constituting the surface of the image forming surface of
the recording medium is dehydrated and activated.
This treatment causes the aluminum anodic oxide layer to undergo
dehydration and condensation of the water content adsorbed on boehmite AlO(OH)
and alumina γ-Al2O3 formed on the outer surface when
the layer is formed, so that activation points are formed thereon. The activation
points react with water content in the atmosphere and behave so as to immediately
return to the original state. Hence, it is important for this treatment to be carried
out immediately before the step of recording. Once the activation points have
been formed, reactive groups of the dye contained in the ink combine at these points,
so that the coloring ability is improved. There is also an advantageous effect
that the water content in the ink is absorbed to increase the quantity of ink
In this first step, a heat treatment, an electromagnetic induction
treatment or a treatment by dry-air blowing can be utilized. In the dry air, active
gas such as H2 or O3 may be mixed. A method of applying a
charge treatment by corona discharging may also be used.
Stated specifically, for example, dry air heated to 60°C is blown
on the aluminum anodic oxide layer at a rate of about 20 liter/min through an
opening of 20 cm × 5 cm. The aluminum sheet on which this aluminum anodic
oxide layer has been formed is passed through the above opening at a speed of about
30 cm/min, and then transported to an ink-jet recording zone. Since this treatment
can not be well effective if the atmosphere or the aluminum sheet has a low temperature,
a tray for the transport may preferably be provided with a sheet heater so that
the sheet can be preliminarily heated up to about 60°C.
At the time the treatment in the first step has been completed, ink-jet
recording (the second step) is carried out on the recording medium. In the ink-jet
recording in the second step, any recording apparatus and recording system applied
to usual recording mediums such as paper can be used.
With regard to ink, there are no particular limitations thereon so
long as it can achieve the desired end. An ink making use of a coloring matter
(a dye) having a good coloring ability to the anodic oxide layer is preferred.
More specifically, in the case of the anodic oxide layer of aluminum or an alloy
thereof, the oxide layer is formed by anodizing carried out under application
of a direct current or an alternating current in an electrolytic solution of sulfuric
acid or the like, setting the aluminum or an alloy thereof to serve as the anode.
Hence, the layer is in a state of still containing many kinds of intermediate
products formed when the aluminum or an alloy thereof is changed into its oxide
in the course of the dehydration and condensation in the anodizing reaction. The
intermediate products are rich in reactivity (e.g., boehmite). Thus, use of a dye
highly reactive with such intermediate products enables improvement of the coloring
ability. Such a dye may include, for example, dyes having at least one kind of
anionic groups. In particular, dyes having a carboxyl group and/or a sulfonic group
The pH of the ink may preferably be on the alkaline side rather than
the acid side. This is presumably because the layer is formed on the anode side
and tends to be dissolved on the alkaline side.
With regard to solvent components of the ink, there are no particular
limitations thereon so long as it can achieve the desired end. However, nonvolatile
solvents such as glycerol utilized in conventional ink-jet recording inks used
on paper or the like and glycols having a high molecular weight remain on the
image forming surface after volatile solvents have been evaporated, as shown, for
example, in Fig. 6.
Fig. 6 graphically show an evaporation loss with time, of an ink
containing a non-volatile solvent. Fig. 6 shows the evaporation loss of the ink
put in a laboratory dish under dry conditions of 60°C. The evaporation loss is
indicated on the ordinate, and the time, on the abscissa. First, volatile components
evaporate when the ink is put in at 60°C, and the evaporation loss increases with
the rate of evaporation, where the quantity of ink is kept constant when the volatile
components have completely evaporated and only non-volatile components have remained.
If it is a quantity more than that acceptable in cells, the surrounding ink droplets
may mutually mix to cause bleeding, possibly resulting in a deterioration of image
In the case of paper, cloth or recording mediums so constructed that
a base material of the image forming surface is capable of absorbing solvents,
such non-volatile solvents permeate into the base material and hence have no influence,
or only an influence small enough to be ignorable, on the dyes constituting the
image on the surface layer. On the other hand, the permeation of non-volatile solvents
in the direction of the base material as in the case when paper or the like is
used do not occur in the case of the anodic oxide layer formed on the surface of
aluminum or an alloy thereof, and hence the solvents remain in the layer to often
cause color mixture, blur, bleeding or the like. Inks prepared using only water
and dyes can not be endowed with a viscosity suitable for the generation of bubbles
in apparatus and for the recording. For such reasons, the use of such non-volatile
solvents in ink is indispensable for enabling effective operation of ink-jet recording
apparatus. Accordingly, in order to prevent the problems caused by non-volatile
solvents, the content of a non-volatile solvent in ink may preferably be so controlled
that the non-volatile solvent holds a volume smaller than the total volume of the
pores present in the region where ink droplets impact against and spread on the
image forming surface.
The ink absorption in the anodic oxide layer is governed by the volume
of pores. Hence, in the ink-jet recording of the present invention the dye in ink
may preferably be in a shot-in quantity set in accordance with the structure of
the anodic oxide layer constituting the image forming surface, in particular,
in accordance with the volume of pores. For example, when the anodic oxide layer
having the structure as shown in Fig. 1 has a cell diameter of about 40 nm (400
angstroms), a pore diameter of about 10 nm (100 angstroms) and a pore depth of
about 10 µm and the recording is carried out under conditions of 400 dpi, it follows
that one picture element has a side of about 63 µm and hence about 2,400,000 cells
are present in it, having pores with an internal volume of about 0.0008 µm3
per pore. Thus, the total volume of the pores per picture element comes to be about
1,900 µm3. A value obtained by dividing this total volume by the area
of one picture element is a reception height, which comes to be 0.46 µm. In this
case, the dye concentration in ink is governed by this reception height. In the
case when the volume per unit ink droplet (ejection quantity) is 30 ng, the reception
height of 0.43 µm gives a dye concentration of about 3%. From the viewpoint of
the degree of coloring and the reflection O.D. (optical density) at colored areas,
the reception height may preferably be 0.2 µm or more in order to obtain sharp
images. In the formation of the anodic oxide layer, the conditions for analysis
should be so set that the layer thickness, cell density and pore size that satisfy
this reception height can be obtained.
In setting conditions as described above, when the ink ejection quantity
is 30 ng and the reception height (hereinafter also often "reception quantity")
of the aluminum anodic oxide layer is 0.46 µm, what is important is that the tolerance
of non-volatile components contained in the ink is not more than the above reception
quantity of the layer. Thus, it has become clear that the image bleeding can be
prevented when the non-volatile solvent is controlled to be mixed in an amount
of 6% by weight or less.
This amount depends on the shapes of cells and pores and the layer
thickness of the anodic oxide (anodized aluminum) layer. Namely, when the layer
thickness is about 20 µm, the non-volatile solvent can be mixed in an amount at
least twice as much as the foregoing. When the cells are in a high density and
also when the pores are large in size, it can be mixed in a much greater amount.
However, its upper limit is about 10% in the case of usual aluminum anodic oxide
layers, and should preferably be in an amount of 5% or less.
If the non-volatile solvent is completely removed, the ink-jet recording
head may clog or the first-ejection performance may become poor, rather often
resulting in a deterioration of image quality. Hence, it is important for the non-volatile
solvent to be mixed in an optimum amount within the above range.
The non-volatile components mentioned above are comprised of dyes,
as well as diethylene glycol, triethanolamine, polyethylene glycol, glycerol, urea
or the like. They may be any kinds of solvents and additives so long as they have
a good I/J (ink jet) suitability and do not adversely affect the printing on aluminum
anodic oxide layers.
In the bubble-jet recording, the volatile components mentioned above
are solvents capable of bubbling upon heating, which may include water, IPA, acetone
and alcohols, and may be any solvents so long as they have a good I/J suitability
and do not adversely affect the printing on aluminum anodic oxide layers.
The volatile components should preferably have an evaporation rate
ranging from 1.0 × 10-5 g/mm2&peseta;sec to 1.0 ×
10-7 g/mm2&peseta;sec in the state that all solvents have
mixed and in a dry environment of 60°C. Here, ink droplets shot in the aluminum
anodic oxide layer surface completely evaporate in a time of from several seconds
to several ten seconds, so that the ink droplets become dry in one scan to several
scans and high-quality images can be recorded without blur or bleeding.
At the time the ink-jet recording has been completed, the image formed
on the image forming surface is subjected to the third step, i,e, the step of
evaporating the solvent components in the anodic oxide layer, on which the image
has been formed, so that dye components of the ink can be fixed.
In this third step, the coloring component contained in ink is the
dye. Other components are components necessary at the time of ink-jet recording
and are components unnecessary after the aluminum anodic oxide layer has been
colored. Hence, such unnecessary components must be removed as soon as the dye
in ink has been received in the cells after recording and its dyeing reaction with
the layer has been completed.
First, in order to make the dye and the layer undergo fixing rection
in a good efficiency, it is important to heat the layer itself to accelerate the
reaction. Next, in order to deposit the dye in the pores of cells, the volatile
components in the ink should be made to evaporate as soon as possible to retain
the dye in the cells. This is important for the formation of images with a high
The ejection quantity is usually so designed as to provide a maximum
recording density, and hence the dye is contained in an amount set at a maximum
value of the reception quantity of the coating. Since, however, the head may eject
the ink in a greatly uneven quantity, a phenomenon may occur such that the ink
is shot in a quantity more than the reception quantity of the coating. Moreover,
to form an image, multi-color inks can be shot in the same site, and a dye itself
may become an unnecessary component, which therefore remains on the layer. When
the dye remains on the layer in this way, the dye may exude when sealing is subsequently
applied in order to improve corrosion resistance of the aluminum anodic oxide
layer. This may cause a deterioration of image quality, or, if the product is used
as it is, the dye may similarly exude in an environment in which resistance to
water or sweating is required, resulting in no durability for image quality.
An example of a specific manner by which the components unnecessary
after recording as stated above will be described below.
First, the aluminum sheet on which the aluminum anodic oxide layer
has been formed and having been subjected to the ink-jet recording is heated with
three infrared lamps of 500 W from the upper part while it is passed over a heat
sheet of 1,000 W at the lower part, which is passed at a rate of travel of about
30 cm/min. In this example, four colors of Y, M, C and Bk are superimposingly shot.
Accordingly, the recorded surface is rinsed with pure water as a post-treatment
to remove excess dyes, followed by drying to obtain an image-recorded product.
Thereafter, this image-recorded product is immersed for 10 minutes in boiling
pure water of about 100°C, to carry out sealing of the aluminum anodic oxide layer,
followed by drying to obtain a finished product.
In the present invention, at the time the ink-jet recording has been
completed, an aqueous polyvalent metal salt solution may be applied to the image
formed on the image forming surface. This makes it possible to produce an image-recorded
product having a fastness to light.
The aqueous polyvalent metal salt solution comprises polyvalent metal
cations such as Cu++, Ni++
and Al+++. Examples are
by no means limited to these, and other polyvalent metal cations may be used so
long as the same effect can be obtained.
As anions that combine with such cations include Cl-,
ClCO3- and CH3COO-. Of course, examples
are by no means limited to these.
This aqueous polyvalent metal salt solution should have a salt concentration
of from 0.05 to 50% by weight, and preferably from 0.2 to 30% by weight.
The polyvalent metal cations in the solution react with the reactive
groups of the dye, e.g., carboxyl groups and sulfonic groups, to form a dye complex.
As previously stated, dyes highly reactive with intermediate products, in particular,
dyes having reactive groups such as carboxyl groups or sulfonic groups are preferred.
Use of such dyes facilitates the reaction with polyvalent metal cations, so that
the dye complex can be formed with ease. The formation of such a dye complex can
prevent decomposition of dye molecules and prevent any discoloration or color
change due to changes with time.
As a method for applying the aqueous polyvalent metal salt solution
to the image formed on the image forming surface, the aqueous polyvalent metal
salt solution may be sprayed on the anodic oxide layer by means of a sprayer or
the like, in case of the use as an interior decoration. It is more preferable
to wash the anodic oxide layer with the aqueous polyvalent metal salt solution.
When image-recorded products are used outdoors and require a reliability,
it is preferable to carry out sealing of the anodic oxide layer using the aqueous
polyvalent metal salt solution.
The relationship between the aluminum anodic oxide cell configuration
and the shot-in ink quantity will be further detailed below.
In the aluminum anodic oxide cell structure as shown in Fig. 1, diameter
of the cell is A µm, diameter of the pore formed in the cells is a µm, and
layer thickness is L µm. Here, the respective aluminum anodic oxide cells are
arranged in the form of substantially regular hexagons and hence have a cell surface
area Sc of:
Sc = 3 sqrt(3) / (8) A2 (µm2)
and a pore surface area Sp of:
Sp = π / (4) a2 (µm2)
Therefore, an area proportion Cp held by pores is:
Cp = 2π / (3 sqrt(3)) square(a / (A))
Therefore, when the barrier layer 5 is disregarded, an ink reception
height Ra (µm) per unit area is:
Ra = L*Cp = 2π / (3 sqrt(3)) square(a / (A))L (µm)
Here, when the volume of ink droplets to be shot in is represented
by Vd (µm3) and the shot-in area by Sd (µm2), the height
h (µm) per unit area, of the ink droplets having been shot in, is:
h = Vd/Sd.
Here, also when the volume percentage held by non-volatile components
in the ink (mixing ratio) is represented by X, a non-volatile component height
t (µm) is:
t = X Vd/Sd (µm).
It is important for the height t not to exceed the ink reception height Ra set
forth above. If t ≦ Ra is not satisfied, the ink may exude to cause a deterioration
of image quality as previously stated. Therefore, it is important to select the
mixing ratio X and the layer thickness L so that;
X Vd/Sd ≦ 2π / (3 sqrt(3)) square(a / (A))L
X Vd/Sd ≦ 1.21 square(d / (A))L
is satisfied. Also, since in general the Vd/Sd is 10 µm and the a/A of the aluminum
anodic oxide layer is 0.25 in ink-jet recording, it usually follows that;
X ≦ 0.0076L*
wherein L* is a dimensionless number.
An example of the production apparatus employing the above ink-jet
recording of the present invention will be described below.
Fig. 7 diagrammatically illustrates the whole production apparatus.
In Fig. 7, reference numeral 710 denotes a recording head, which is an ink-jet
recording head with 128 nozzles of 400 dpi, having an ejection quantity of 25
ng per dot. The apparatus is provided with four recording heads corresponding to
four colors of Y (yellow), M (magenta), C (cyan) and Bk (black) and is so set
up that a full color image can be recorded at one scan. Reference numeral 701
denotes a recording medium comprising, as previously described, a plate, sheet
or foil made of aluminum or an alloy thereof on the surface of which the anodic
oxide layer has been formed to serve as the image forming surface. A plurality
of recording mediums 701 are set in a stocker 711, which are successively sent
to a belt conveyor by means of a transporter 712 and fed forward to a printing
tray 715. Reference numeral 714 denotes an auxiliary roller for transport.
The recording medium 701 fed to the printing tray 715 is firmly secured
by suction onto the tray by the operation of a suction pump 716. The recording
medium 701 on the tray 715 is sent to a zone where the first treatment step (the
step of dehydration and activation) is carried out, and is heated by irradiation
with infrared rays from infrared lamps 704, so that the water content present in
the anodic oxide layer of the recording medium 701 is removed and also dehydration
reaction take place to activate the layer. A fun 705 is also rotated to ventilate
the zone, whereby the treatment at the first step can be made more effective.
The recording medium 701 is sent out by the operation of a feed motor
717 from the zone of the first treatment step, and immediately thereafter the
recording head 710 carries out ink-jet recording. In this second step ink-jet recording,
various ink-jet recording systems such as a piezoelectric type and an electrostatic
type can be used. A bubble-jet recording system is preferred since it can stably
carry out high-speed recording.
As for the recording process, two-pass or four-pass printing may
be employed if the problem of bleeding or the like occurs when one-pass printing
is employed. As inks used here, those having various composition can be used.
As previously stated, those in which the types of dyes and the content of non-volatile
solvents have been suited for use in anodic oxide layers may preferably be used
under appropriate selection. The recording medium 701 on which an image has been
recorded is immediately transported to a zone in which the third step treatment
is applied. This step is taken in order to evaporate and send off the volatile
components of inks present in the anodic oxide layer on which an image has been
formed, and also allow the dyes in inks to react with the layer to promote dyeing
so that the image can be firmly fixed. In this apparatus, this third step is carried
out by a heating means 703 having a fun and infrared lamps in combination. What
is intended in the third step is to fix the dye in the inks on the layer. It is
also a process preferable for fixing dyes that the water and oxygen in the air
react with the anodic oxide layer to form a hydroxide to seal pores in the layer.
Hence, different from the first step, it is not always necessary to operate the
The recording medium 701 (an image-recorded product) having been
subjected to the above three steps is transported to a stocker 719 via a conveyor
720 and a feed roller 721, and received at a given position by a handler 718.
In the example shown in the drawing, the recording medium 701 has
the shape of a rectangular sheet. The tray 715 on which it is transported is appropriately
adjusted so as to be conformable to the form of the recording medium. For example,
a spacer 811 as shown in Fig. 8 may be used so that the tray can be adapted to
the recording on a disk type recording medium. This apparatus may also preferably
have a means for adjusting the distance between the recording head and the image
forming surface of the recording medium in accordance with the thickness of the
In order to promote the effect of the heating in the first step and
the third step, the tray may be auxiliarily provided with a heating means such
as a heater so that, for example, the recording medium is preheated before each
treatment. This improves heating efficiency also when a relatively large-sized
recording medium with a large heat capacity is treated, and enables effective
When the recording medium is heated, any dimensional distortion may
occur because of thermal expansion to cause a deviation in the width direction
of recording and the feed direction, bringing about the problems of white stripes
appearing on recorded images and deviation of print size. In such a case, it is
preferable to use, for example, as shown in Fig. 9, a system in which the surface
temperature of the image forming surface of a recording medium 901 is detected
by a temperature sensor 902, the detected values are amplified by an amplifier
(Amp), the amplified values are digitized using an A/D converter (A/D) to compare
the digitized value with a preset value by means of a comparator and then the signals
obtained are sent to a recording head 910 and a motor 903 in the form of optimum
delay signals with respect to clock signals to make control so that the recording
medium can be correctly positioned.
As previously stated, in the anodic oxide layer of aluminum or an
alloy thereof, the ink reception quantity is greatly influenced by the sealing
percentage of the pores constituting the layer, the layer thickness, the pore size,
the cell density and so forth. However, these properties of the layer may become
non-uniform among a plurality of recording mediums formed under the same conditions,
and may cause a non-uniformity in image quality, in particular, a non-uniformity
in image quality between lots when the recording is carried out in the second
step under the same conditions. In such a case, the problem can be solved by adding
a control means for adjusting the ejection quantity by controlling recording head
pulse width, head temperature, time between full pulses and so forth, on the basis
of a feedback of the results obtained by previously printing characters on the
anodic oxide layer at its part on which no images will be recorded and pre-examining
their print density, balance of shade between colors and so forth.
In order for the recording medium to be transported in a good precision,
a mark may be made at a non-print area of the recording medium by etching or pressing
so that its position can be read by a suitable reading means to always make sure
the position of the recording medium and control the transport means in accordance
with the position, whereby the recording medium can be transported in a good precision.
When the recording medium has a warp, it is effective to add to the roller or the
like a function to correct the warp. If the above mark may damage the commercial
value of products, it may be removed by means of a shearing press or the like after
A member having the part comprised of aluminum or an alloy thereof
on which the image has been formed in this way may be used as it is without sealing
of the whole pores if it is used, for example, for interiors. If it is used for
exteriors where a reliability is required, the sealing of pores may preferably
be additionally made to form a product.
Next, examples of the mechanism in the second step ink-jet recording
used in the process and apparatus of the present invention will be described below
In the ink-jet recording on the aluminum anodic oxide layer, as previously
stated, the aluminum anodic oxide layer itself has no ink permeability and also
the pores serving as an ink receptor have not so large volume. Moreover, there
is a limit to increasing the evaporation of inks. Hence, especially in the case
of a recording process where multi-color inks are simultaneously shot in plurality,
the above process alone may be unsatisfactory in image quality.
Accordingly, the recording is not carried out all at one time using
nozzles arranged in plurality, but recording scans are divided into several times
and the recording is reciprocally carried out. Use of such a system in combination
makes it possible to obtain high-quality images. Namely, this is a system in which,
when recording is carried out by scanning n-times, nozzles are arranged in plurality
(m-nozzles) and a printing face is forwarded by m/n, where the printing is repeated
to form picture element units of n × a, and n × a picture elements
are filled by scanning divided into n-times. This makes it possible to eliminate
uneveness in recording scans, to gain time until inks are dyed and fixed, and to
keep a drying time for which ink reception at pores can be completed.
Fig. 10 illustrates a specific example of the formation of dots on
the recording medium of the present invention. Fig. 10 shows a state in which Cink
and Y-ink are simultaneously shot in to form dots. Squares shown in the first
scan represent the position of the recording head and the scope in which inks can
be shot in at the scan. The squares painted out in black are areas in which recording
signals have been actually given to make a record, and the apparatus is so set
as for a lower 1/2 part of the head to give a half shot-in quantity. Next, at the
second scan, paper is forwarded by 1/2 of the nozzle width of the head to make
a record at the remaining area in which no record has been made at the first scan,
using the upper half of the recording head. Record is carried out also at the
lower half in a like pattern to make a record leaving a 1/2 area unrecorded. This
is a process in which the recording is further repeated for the third scan and
the fourth scan to form a 100% image-recorded area. Here, such a recording process
is called the "two-pass printing".
This two-pass printing can eliminate the uneveness for each scan.
Since, however, two color inks are simultaneously shot in as shown in Fig. 10,
the reception quantity of the aluminum anodic oxide layer is required to be doubled.
This is unsuitable for those having a thin aluminum anodic oxide layer as previously
stated. Accordingly, in the case when the multi-color printing is carried out and
in the recording process in which inks are simultaneously shot in at the same
position, it is necessary to change the pattern for each color to make a record
so that each color ink is shot in at a different position for each pass.
Figs. 11A to 11H and 12A to 12H illustrate specific examples in which
patterns are changed for each color to make a record. In the examples shown in
Figs. 11A to 11H and 12A to 12H, Y, M, C and Bk four color inks are used and recording
is carried out using a recording apparatus as shown in Fig. 13, in which four
heads each having 64 nozzles are arranged in parallel. In Fig. 13, reference numeral
1201 denotes recording heads corresponding to four colors; 1202, an ejection orifice;
1203, a carriage; 1204 and 1205, aluminum sheet feed rollers; 1206, an aluminum
sheet having an aluminum anodic oxide layer on its surface; 1207, a rail; and
1208, an encoder.
As shown in Figs. 11A to 11H and 12A to 12H, when four-color recording
is carried out, 4×4 picture elements are arranged so that the four colors
do not overlap one another, and recording signals are selected for each color
so that inks are shot in one pass for four dots among them. Figs. 11A to 11H and
12A to 12H show 16 picture elements in the nozzle array direction and 16 picture
elements in the scan direction, and the apparatus is so set as to form a 100%
image-recorded area upon scanning repeatedly carried out four times. Similar to
the example previously described, the squares painted out in black are areas in
which inks are shot. The aluminum sheet is forwarded with respect to the heads
by 16 nozzles each as a second pass, a third pass and a fourth path toward the
right side to carry out recording. Thus, inks are not simultaneously shot in for
each color, ink droplets are received in pores within the time the respective
scans are repeated and no bleeding may occur between colors, so that it becomes
possible to form high-quality color images. This recording process is herein called
"color-by-color pass printing".
Table 1 shows how the respective printing systems are effective on
image quality. Criterions of judgement on image quality for each system are shown
together. "One pass" indicates the recording carried out by 100% shot-in at usual
one scan; "Two passes", the recording process described above with reference to
Fig. 10; and "Four passes", the recording process described above with reference
to Figs. 11A to 11H and 12A to 12H. "Monochrome" indicates an instance where the
recording is carried out in Bk monochrome; and "Full color", the recording process
in which simultaneous recording is carried out using Y, M, C and Bk four color
inks under three-color overlap at most.
As will be seen from Table 1, in the case of the monochrome, the
scanning line irregularity and the bleeding on the recording surface are reasonably
prevented so long as the recording is divided into at least two passes, and there
is no problem in practical use. In the case of the full-color printing, high-quality
images can be achieved by four-pass printing where passes are separated for each
AA: No bleeding occurs at all and images have a good quality.
A: Bleeding slightly occurs but images are at a level not problematic in practical
B: Bleeding occurs in areas where at least two colors are superposed.
C: Bleeding greatly occurs and images have a very poor quality.
A printing system employing an image forming process according to
another embodiment of the present invention will be described below.
In order to increase recording density, it is necessary to decrease,
on the recording surface, areas on which dyes are not fixed. For example, as shown
in Figs. 14A and 14B, it is suitable for ink droplets to each have a diameter
of about 100 µm under recording conditions of 360 dpi. Since the distance between
the centers of ink droplets comes to be 70.5 µm, ink droplets 21 form dots in
such a way that they overlap with each other on an anodic oxide layer 22 formed
on an aluminum base 23. Fig. 14A is a top view of droplets in Fig. 14B.
In contrast, if, for example, images are recorded at 360 dpi in an
ink droplet diameter of 70.5 µm, areas having no dyes remain on the surface as
shown in Figs. 15A and 15B. Fig. 15B is a cross section along the line 15B-15B
in Fig. 15A.
When such areas having no dyes remain, no sufficient density can
be achieved no matter how high the dye density at each dot is made.
Thus, it follows that dots are so formed as to be in the relationship
as shown in Figs. 14A and 14B.
However, the anodic oxide layer 22, which is different from paper
or recording mediums made up to have an absorptive base material, has no ink permeability,
and hence, when a plurality of dots are formed in the state of the ink droplets
as shown in Figs. 14A and 14B, the ink having impacted on the surface acts in
such a way that the ink droplets come together because of surface tension inherent
in the ink.
More specifically, ink droplets standing as shown in Fig. 16A turn
into a state as shown in Fig. 16B.
As evaporation of volatile solvents takes place from this state,
an ink having increased in dye concentration is left on the surface, and this ink
also comes toward the center because of surface tension (Fig. 16C and 16G). With
a further progress of this course of action, an image having a dye in a large
quantity at the center and in a gradually smaller quantity toward the outside is
formed, as shown in Fig. 16D. Also, in some cases, non-volatile solvents may remain
at the center in a concentrated state.
In the case of monochromes, this brings about an uneven density to
lower the quality level of images. In the case of color images, this may cause
bleeding of inks with different colors adjacently formed.
Figs. 16E and 16F show shapes of ink droplets 21 on the surface of
anodic oxide layer 22 of Figs. 16A and 16B, respectively, viewed from the top.
In instances in which ink droplets are superimposingly shot, the
volume of ink droplets increases as shown in Figs. 17A and 17B, to cause ink run-over,
so that even dye-free areas 24 (Fig. 17A) are colored as shown in Fig. 17B.
Figs. 17C and 17D show shapes of ink droplets 21 on the surface of
anodic oxide layer 22 of Figs. 17A and 17B, respectively, viewed form the top.
Now, in the present invention, as shown in Figs. 18A to 18F and Figs.
19A to 19F, after volatile solvents of ink droplets having impacted first have
substantially evaporated (Figs. 18A to 18C), the next ink droplets are made to
impact (Figs. 18A to 18C). Thus, neither uneven density nor bleeding as stated
above may occur.
Figs. 18G through 18L show shapes of dots and ink droplets on the
surface of anodic oxide layer of Figs. 18A through 18F, respectively, viewd form
This can be accomplished by recording dot-interval images several
times as shown in Fig. 20.
More specifically, at first-pass printing, nozzles N1 and N3 are
simultaneously driven to print odd-numbered lines; at second-pass printing, nozzles
N2 and N4 are simultaneously driven to print even-numbered lines; at third-pass
printing, nozzles N2 and N4 are simultaneously driven to print odd-numbered lines;
and at fourth-pass printing, nozzles N1 and N3 are simultaneously driven to print
Thus, dots in the same pass become distant by two dots (DB in the
drawing) and hence it becomes possible to prevent any bleeding caused by dots in
the same pass and between passes.
In the case of color images, this procedure may be similarly repeated
so that a first color is fixed and thereafter the next color is fixed.
In this case, in order to prevent misregistration between colors,
multi-color registration may be carried out by a mechanical means or electrical
means known in the art.
The present invention will be described below in greater detail by
On the surfaces of A4 size aluminum sheets (sheet thickness: 0.5
mm) on which aluminum anodic oxide layers of about 10 µm thick each had been formed,
images were formed along the steps according to the process of the present invention,
using the recording apparatus as previously described and also using inks.
In the first step and the third step, heating and drying were employed,
and were carried out under conditions as shown in Table 2 below, i.e, appropriate
combination with no heating, heating at 40°C or heating at 60°C. Image quality
was evaluated on the recorded images obtained. Criterions and results of the evaluation
are shown together in Table 2. As is seen from the results shown in Table 2, good
images can be finally obtained when the heating at 60°C is applied in the first
treatment step and the heating at 40°C or above is applied in the third treatment
step. As is also seen therefrom, no good images can be formed even though the
third treatment steps are carried out under any conditions, when the first treatment
step is omitted.
AA: No bleeding occurs at all and images have a good quality.
A: Bleeding slightly occurs but images are at a level not problematic in practical
B: Bleeding occurs in areas where at least two colors are superposed.
C: Bleeding greatly occurs and images have a very poor quality.
Influences of the solvent proportion of non-volatile component in
ink when the ink-jet recording was carried out on the aluminum anodic oxide layer
according to the present invention were examined using glycerol as the solvent,
to make evaluation as reported below.
Using 100 g of ink solutions prepared by mixing 3 g of a dye, glycerol
in the amount as shown in Table 3 below and the balance of water and IPA in a
ratio of 10:1, bubble-jet type ink-jet recording was carried out along the steps
according to the process of the present invention, on aluminum sheets (A) on which
anodic oxide layers (aluminum anodic oxide layers) with a layer thickness of 10
µm each had been formed and aluminum sheets (B) on which anodic oxide layers (aluminum
anodic oxide layers) with a layer thickness of 20 µm each had been formed.
Image quality was evaluated on the recorded images obtained. Criterions
of the evaluation are the same as those in Example 1. Results obtained are shown
together in Table 3. As is seen from the results shown in Table 3, in the case
of the aluminum sheet having an aluminum anodic oxide layer with a layer thickness
of 10 µm, a good image quality is attained when the glycerol is in a percentage
of 5% or less. In the case of the aluminum sheet having an aluminum anodic oxide
layer with a layer thickness of 20 µm, a better image quality is attained when
the glycerol is in a percentage of 10% or less.
Amount of glycerol
10µm thick layer
20µm thick layer
On aluminum sheets with a sheet thickness of 0.5 mm on which aluminum
anodic oxide layers of about 20 µm thick each had been formed, which were subjected
to dehydration and activation treatments, images were formed by bubble jet recording,
using an ink composed of the following.
C.I. Direct Black 168
3% by weight
10% by weight
5% by weight
82% by weight.
Next, the aluminum sheets on which images were thus formed were washed
with an aqueous 10% by weight AlCl3 solution for 3 minutes, followed
by further washing with water for 5 minutes.
Samples thus washed and samples having been not washed were tested
for their 50 hour light-fastness by the use of a fade-0-meter (ATLAS Ci35).
Evaluation was made using a reflection densitometer (MACBETH R-D915),
where reflection densities were measured before the light-fastness test and after
the light-fastness test to compare the retensions.
Retension = Reflection density after light-fastness test / (
Reflection density before
light-fastness test) x 100
Results obtained are shown in Table 4.
The washing with an aqueous polyvalent metal salt solution is seen
to bring about an improvement in light-fastness.
Retension of reflection density
80% or more
Less than 80%
On 0.5 mm thick aluminum sheets on which aluminum anodic oxide layers
of 20 µm thick each had been formed, images were formed by bubble jet recording
as in Example 3, using the same ink as used in Example 3.
Next, samples were prepared, some of which were subjected to sealing
of pores of anodic oxide layers by the use of an aqueous 1% by weight AlCl3
and some of which were not.
Evaluation was made in the same manner as in Example 3.
Results obtained are shown in Table 5.
The sealing of anodic oxide layers by the use of an aqueous polyvalent
metal salt solution is seen to bring about an improvement in light-fastness.
Retension of reflection density
85% or more
Less than 80%
As described above, according to the image forming process of the
present invention, the reactivity with dyes and the ink reception quantity are
improved when the anodic oxide layer formed on the surface of a plate, sheet or
foil of aluminum or an alloy thereof is subjected to the dehydration and activation
treatments before the ink droplets are imparted thereto. Also, recorded images
having a superior image performance can be finally formed on the anodic oxide
layer when, after the ink droplets have been imparted, the volatile components
in inks mixedly present in the layer are evaporated to fix the dyes (coloring
matter) in the inks on the layer to thereby improve ink fixing performance.
According to the apparatus of the present invention, recorded images
having a superior image performance can be finally formed on the anodic oxide
layer provided on the surface of a plate, sheet or foil of aluminum or an alloy
thereof, according to the process as described above.
The decorative aluminum plate, sheet or foil produced according to
the present invention has been treated and processed in the manner as described
above, before the recorded images are formed, i.e., before inks are imparted to
the anodic oxide layer provided on the surface of a plate, sheet or foil of aluminum
or an alloy thereof, and hence has a superior image performance.
According to the present invention, images and decorative aluminum
sheets having a superior light-fastness can be formed when, after recorded images
have been formed, the aqueous polyvalent metal salt solution is applied to the
anodic oxide layer formed on the surface of a plate, sheet or foil of aluminum
or an alloy thereof.
According to the present invention, the coloring ability of ink can
be improved when the anodic oxide layer formed on the surface of a plate, sheet
or foil of aluminum or an alloy thereof is subjected to the dehydration and activation
treatments before the ink droplets are imparted thereto. Also, in the recording
carried out plural times by imparting ink droplets so as to form dot-interval images,
in the case when the next ink droplets are imparted adjacently to the ink droplets
first imparted, the next ink droplets are imparted to the adjacent areas after
the ink at least in the areas where they are superimposed on the ink droplets first
imparted has been substantially fixed and the dye in the ink has been also fixed.
In the case when the next ink droplets are imparted superimposingly to the ink
droplets first imparted, the next ink droplets are superimposed after the ink
droplets first imparted has been substantially fixed and the dye in the ink has
been also fixed. This makes it possible to form images free of ink bleeding and
to finally form recorded images having a superior image performance on the anodic
oxide layer, and decorative aluminum sheets having such recorded images.
Before ink-jet recording, an image forming surface comprising an
anodic oxide layer of aluminum or an alloy thereof is dried and activated. After
the recording, a treatment to remove solvent components of ink and fix a dye in
the ink is applied.