JPH0525677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming a relief image using an inkjet recording method.

More specifically, characters are printed using an inkjet printer on a recording sheet that has a recording layer made of a water-developable photosensitive resin, accepts water-based ink used in inkjet recording, and allows the water-based ink to dry quickly. After printing or drawing an image, the entire surface is irradiated with light to photocure the recording layer in the non-image area on which ink is not applied and make it water insoluble, and the recording layer in the water-soluble image area that is not photocured is removed by washing with water. This invention relates to a method for forming a negative relief image on characters or images printed by an inkjet printer, which is characterized by the following.

The inkjet recording method has no noise and is easy to develop,
Because it does not require fixing, can perform high-speed recording, and can perform multicolor recording, its use is becoming widespread in facsimile machines, word processors, terminal printers, etc. Recently, high-resolution color inkjet printers have been developed, and are used for remote sensing, CAD, medical imaging, color design, and other applications.
Its use is expanding to applications such as gravure printing in the fields of printing layouts and color printing proofs, or creating so-called pictorial full-color copies with a high image quality close to that of silver halide photography.

[Conventional technology]

Conventionally, sheet-like products with a photosensitive resin layer are
Negative or positive original film is stacked and light is irradiated through the film to harden the photosensitive layer in the exposed areas, and the photosensitive resin layer in the non-exposed areas that is not photocured is dissolved and removed with a suitable solvent such as water or alkaline water. It is a well-known technique to form a negative relief image by this method, and is also used in fields such as printing plates, production of proofing films, and resists for electric circuit boards.

[Problem that the invention seeks to solve]

The conventional method involves overlapping a negative or positive transparent original film with a photosensitive sheet, irradiating the entire surface with light, and forming a relief image using photocrosslinking or photodecomposition of the recording layer of the photosensitive sheet. This invention, which is completely different, does not require original film;
The present invention was completed by focusing on the characteristics of the inkjet recording system and its technical superiority, which is especially advantageous for making color copies.

[Means for solving problems]

By printing or drawing on the recording sheet of the present invention using an inkjet printer, a relief image is directly and easily formed on the recording sheet through a process of light irradiation and water washing. In other words, it is made of photosensitive resin that can be developed with water to process electric signals related to image information obtained from color scanners, etc., as well as character and image information stored on floppy disks and magnetic tapes of personal computers, or VTR magnetic tapes. Direct printing or drawing is performed on the recording sheet of the present invention provided with a recording layer using an inkjet printer that uses water-based ink, and the printed or drawn portion of the recording layer is swollen with the water-based ink to reduce photocurability. When the entire surface of the recording sheet is irradiated with light, the photosensitive recording layer in the non-image area where no ink is applied is photocured and becomes water-insoluble, whereas the recording layer in the image area that is swollen by the solvent of the water-based ink is Since the water-soluble recording layer remains uncured or has a low degree of photocuring, by washing away the water-soluble recording layer in the image area and drying it, it can be used as a negative type (non-curable) for characters and images obtained with an inkjet printer. The present invention provides a completely new image forming method for creating a relief image of an image area).

Inks used in the inkjet recording system include oil-based inks, water-based inks, and magnetic fluid inks, but water-based inks are mainly used from the viewpoint of reliability in preventing clogging of nozzles in inkjet printers.

Water-based inks for inkjet recording generally contain water-soluble dyes and their solvents as main components, as well as other binders, physical property modifiers such as viscosity and surface tension, and fungicidal and fungicidal agents. The main component of the ink solvent is water, and in order to prevent clogging of the inkjet printer head, water-soluble solvents such as glycols, glycol ethers, azides, and pyrrolidones that have low vapor pressure at room temperature and have water retention properties are used. It is common to use a combination of solvents.

[Effect]

The inkjet recording sheet used in the present invention has a recording layer mainly composed of a water-developable photosensitive resin such as a water-soluble photosensitive resin, and the inkjet recording sheet can be used immediately after printing with an inkjet printer. Furthermore, when a sheet of general paper is pressed against the image area, undried ink is not transferred to the paper, and the ink receptivity and drying properties are excellent.
However, more strictly speaking, water-based ink permeates through the thickness of the recording layer, and some of the solvent consisting of water and wetting agents such as glycols remains, causing the ink to penetrate into the recording layer in the image area. The water-soluble photosensitive resin is in a swollen state. When the entire surface of a printed recording sheet having a recording layer in such a state is irradiated with light,
While the non-image area on which ink is not applied becomes water resistant through crosslinking and polymerization reactions caused by light irradiation, the recording layer in the swollen image area on which ink is applied is not cured at all or has a low degree of curing, causing the image to deteriorate. The degree of crosslinking, that is, the degree of water resistance, of the recording layer in the area and the non-image area differs greatly. In other words, the non-image area of the object irradiated with light becomes water resistant,
On the other hand, since the image portion maintains water solubility, there is a significant difference in water solubility between the two. The present invention is based on the discovery of this extremely interesting and important phenomenon, and by removing the water-soluble recording layer in the image area made of uncured or low-cured water-soluble photosensitive resin with water, it can be made waterproof by light irradiation. This invention led to the invention of a completely new method for forming a relief image in which a relief image of a non-image portion is obtained.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to FIGS. 1 to 3. However, this explains the basic concept of the present invention, and the present invention is not limited to these embodiments.

When printing or drawing is performed using an inkjet printer using water-based ink on recording sheet A (Fig. 1), which has a recording layer mainly composed of a water-soluble photosensitive resin, the flying particles of the water-based ink become independent as shown in Fig. 2. The ink particles 1, 2, 3 or connected ink particles 4 are deposited on the recording layer A, and in the image area, a recording sheet is obtained in which the dye and solvent components of the ink permeate in the thickness direction of the recording layer. A recording sheet B is obtained by irradiating the entire surface of the recording sheet with light to photocure the recording layer in the non-image area and make it water insoluble. Next, the uncured recording layer portion of the image area (1,
2, 3, 4) are washed with water, removed and dried, and the surface area of the base material corresponding to the image area (5, 4 in Figure 3) is removed.
By exposing the parts 6, 7, and 8),
A recording sheet C (FIG. 3) having a negative relief image is created for the image printed or drawn using an inkjet printer.

Examples of photosensitive resin compositions capable of water reaction forming the recording layer of the recording sheet used in the present invention that forms relief images by an inkjet recording method using water-based inks include (a) photodecomposition reaction of diazo compounds; A water-soluble photosensitive resin composition that is cured and rendered water insoluble by a photochemical reaction such as a photocrosslinking reaction based on (b) photopolymerization due to a radically reactive unsaturated double bond, or a photocrosslinking reaction is used.

Specifically, the following water-soluble photosensitive resin compositions can be mentioned, for example.

(a) A combination resin composition of a water-soluble polymer compound and a dichromate, a diazonium compound, a tetrazonium compound, a bisazide compound, etc., which make the water-soluble polymer insoluble in water through a photoreaction.

Examples of water-soluble polymer compounds include gelatin, casein, cellulose derivatives, poly(meth)acrylic acid and its salts, polyvinyl alcohol, polyacrylamide, or modified products thereof, polyvinylpyrrolidone, or modified products thereof. Further, if necessary, resin emulsions such as polyvinyl acetate based water-soluble polymer compounds, water-soluble acrylate monomers, and the like may be blended.

(b) A composition formed by blending a photoreaction initiator with a photopolymerizable or crosslinkable water-soluble resin containing a radically polymerizable or crosslinkable unsaturated double bond such as a vinyl group or an acrylic group.

This type of radical photoreactive water-soluble resin includes quaternary ammonium salt addition type acrylic modified resin which is made by adding a quaternary ammonium salt to impart water solubility and further introducing an unsaturated double bond. Examples include water-soluble acrylic monomers (such as hydroxyethyl (meth)acrylate), diacetone acrylamide, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and polyethylene glycol di(meth)acrylate.

Preferably, the applicant files the application first (patent application
Various modified natural polymers having photoreactive unsaturated double bonds introduced therein (No. 58-250560) are suitable. The modified natural polymer, which is photopolymerizable or crosslinkable and water-soluble, can be obtained by reacting the epoxy group of a vinyl epoxy compound with a natural polymer starting material such as casein, gelatin, starch, or carboxymethylcellulose. A method of reacting the carboxyl group of carboxylic acid, a method of reacting the hydroxyl group of vinyl hydroxide such as hydroxyethyl (meth)acrylate, a method of reacting the methylol group of vinyl N-methylol compound, a method of reacting the aziridine group of vinyl aziridine compound. It can be obtained by a reaction method, etc.

In order to photopolymerize and crosslink the photoradically reactive water-soluble photosensitive resin, known initiators such as ketones, benzoins, quinones, and thioxanthones are used as photoradical reaction initiators,
In some cases, a sensitizer may also be used.

The essential condition for the resin composition forming the recording layer of the inkjet recording sheet used in the present invention is that it contains the above-mentioned photosensitive resin capable of water phenomenon as a main component. (a) Ink receptivity of the recording layer. and improved dryness,
Other non-photocurable resins and organic and inorganic pigments may be appropriately blended for the purpose of obtaining faithful ink dot recording properties and (b) further improving the washing removability of the recording layer in the image area. good.

In order to visualize the relief image on the recording sheet prepared according to the present invention, there is a method of dyeing the recording layer of the relief image with a dye, or a method of pre-containing a dye or a pigment in the recording layer resin composition. Any method may be used, including a method of forming a relief image that is later visualized by the relief image forming method of the present invention.

The coating amount of the recording layer is preferably 0.5 g/m ² to 10 g/m ² , and any coating method such as air knife, Meyer bar, roll, or knife coating may be used.

The base material sheet that is the support of the recording sheet 1 includes coated paper, resin-impregnated paper, resin-coated paper or melt-extrusion coated paper of thermoplastic resin, transparent or opaque plastic film such as polyester, synthetic paper, and metal-deposited paper. Alternatively, a vapor deposited film, metal plate, etc. can be used. These base sheets may be subjected to an anchor coating treatment in order to impart adhesion to the recording layer.

There are no particular limitations on the aqueous ink for inkjet recording used in the present invention, and any aqueous ink used in commercially available inkjet printers can be used.

On the other hand, in order to amplify the difference in photocurability between the recording layer in the image area that is swollen by the solvent of the aqueous ink and that in the non-image area, which is the technical basis of the novel relief image forming method of the present invention. In order to further reduce the photocurability of the image area, the dye of the water-based ink can be selected, pigments can be added to hide the irradiation light, and radical polymerization inhibitors, radical polymerization inhibitors, etc. can be added to the solvent of the water-based ink. Components such as ultraviolet absorbers that inhibit the photocuring reaction of the water-soluble photosensitive resin forming the recording layer may be added.

Carbon arc, high-pressure mercury lamp,
A commonly used ultraviolet printing machine with a light source such as a metal halide lamp is used.

In the present invention, characters and images on a CRT display of a personal computer or word processor are printed using an inkjet recording printer, and then the entire surface of the recording sheet is irradiated with light, washed with water, and dried. By obtaining a relief image of the non-image area and visualizing it by staining if necessary, it is possible to easily create a negative relief image directly from the inkjet printer for the image printed with the inkjet printer. It is something to create. Image on CRT Display A negative image on the CRT display obtained by black-and-white reversal operation is drawn with an inkjet printer, and a relief image of the same positive image as the original can be easily created using the relief image forming method of the present invention. It is also possible to form

Also, the RGB of the color image on the CRD display
YMCBK (yellow,
It is also possible to individually take out and print each color (magenta, cyan, black) and create relief images of each color individually using the method of the present invention.

Furthermore, since it is possible to easily create relief images of color-separated image patterns obtained with a color scanner for plate making or image patterns obtained with a monochrome scanner, it is possible to easily create relief images of image patterns obtained with a color scanner for plate-making, making it easier to paste, compose, and correct images. It is also possible to utilize the relief image recording sheet.

As described above, the method for forming a relief image of the present invention, which takes advantage of the advantages of direct formation of a relief image using the inkjet recording method and the features of the safe and simple water phenomenon, has the potential to be used in a wide variety of applications. For example, it is extremely useful for lithography and letterpress printing plate making, printing color proofing material, design and color proofing material for textiles and dyed products, checking sheet for printed wiring boards, second original drawing sheet, OHP film, etc. It is.

Further explanation will be given below based on examples.

Example 1 Polyethylene terephthalate film (100μ
An anchor coating solution having the composition shown below was applied to one side of the sample (m) using a Meyer bar method, and dried at 100°C for 1 minute to give an anchor coating treatment with a dry weight of 0.5 g/m ² .

Parts by weight Vinylidene chloride acrylonitrile copolymer 10 Methyl ethyl ketone 100 Trichloroacetic acid 5 A recording layer having the following composition with a dry weight of approximately 5.0 g/m ² was coated on the anchor-coated surface of the polyethylene terphthalate film using a Mayer bar method and heated at 90°C. The inkjet recording sheet was prepared by drying for 3 minutes.

The recording layer of the sheet was dry without blocking, and there was no problem in handling it when printing with an inkjet printer.

Part by weight Diacetone acrylamide Acrylamide copolymer (copolymerization ratio 35/65) 5 Polyvinylpyrrolidone 5 Water-soluble diazo resin (condensation product of paradiazophenylamine and formaldehyde) 0.8 Water 80 Isopropyl alcohol 10 Next, the inkjet was prepared for recording. Alphabet characters and images are recorded on the sheet using a color inkjet printer (Io-0700 4-color ink manufactured by Sharp Co., Ltd.) in 7 display colors (yellow, magenta, cyan, black, red, green, and blue). After that, use an ultraviolet printing machine (Flash Dry LIM-150).
(manufactured by Ushio Inc.) for 10 seconds, and then washed with room temperature water with a water pressure of 1.5 kg/cm ² spouted from the nozzle.
Only the image areas on which the water-soluble inks of each color were applied were eluted, and a relief image of the non-image areas on which no ink was applied was obtained.

Furthermore, the recording sheet on which the relief image was formed was soaked in an aqueous solution of black dye at 40°C having the composition shown below.
After being immersed for a minute, it was washed with water and dried to obtain a relief image stained black. In addition, the part of the recording sheet that has been washed away and corresponds to the image part of the recording sheet having the black-dyed relief image, especially the part on which independent yellow-magenta, cyan, and black ink particles are placed, has a diameter of about 190 μm and is almost true. It was circular and faithfully recorded the particle shape of the ink droplet.

Composition of aqueous dye solution Direct Fast Black B-160 in parts by weight 2.5 Ethylene glycol 10 Water 90 When this recording sheet with a relief image dyed in black was projected with an overhead projector, clear white characters with a black background were printed. and a projection of the image was obtained on the screen.

Example 2 The recording sheet created in Example 1 Characters and charts mainly consisting of drawing lines on the CRT display were printed using only black ink using an inkjet printer Io-700, and irradiated with light in the same manner as in Example 1. Then, the relief image of the non-image area obtained by washing with water was dyed with an aqueous black dye solution, washed with water, and dried to obtain a recording sheet in which the non-image area was black.

When this recording sheet was projected using an overhead projector, a clear projected image was obtained on the screen, with the characters and lines highlighted against the black background.

Example 3 The line drawing on the CRT display in Example 2 was reversed to create negative characters and figures on the original drawing.
After obtaining the negative image on a CRT display, the negative image was printed on the recording sheet prepared in Example 1 using an inkjet printer (Io-700).
A relief image was obtained by irradiating light and washing with water in the same manner as above. The relief image was dyed with an aqueous black dye solution, washed with water, and dried to obtain a recording sheet having the same black relief image as the original image. This recording sheet was projected using an overhead projector to produce a clear projection screen with black characters and lines, making it suitable for use as an OHP film.

Example 4 A recording layer having a dry weight of 5.0 g/m 2 consisting of the following recording composition having receptivity to the water-based ink jet recording inkjet inkjet polyester film (100 μm) which had been previously anchor-coated as used in Example ¹ was coated with a Mayer bar. A recording sheet was prepared by coating the film and drying it at 100°C for 2 minutes. The recording layer of the recording sheet did not block, and there was no problem in handling when printing with an inkjet printer.

Parts by weight Acrylic modified casein 5 Polyvinylpyrrolidone 5 Methylbenzoylformate 0.5 Water 45 IPA 45 Acrylic modified casein resin was prepared as follows.

100 parts by weight of casein (hereinafter all parts refer to parts by weight) and 350 parts of a water/isopropanol (50/50 weight ratio) mixed solvent were charged and stirred at 40°C. After adding 2 parts of potassium hydroxide and stirring for 30 minutes, 30 parts of glycidyl acrylate and 1 part of zinc oxide were added, and the temperature was raised to 60°C and stirred for an additional 30 hours to undergo radical polymerization and crosslinkable unsaturated double bonds. A casein modified product having the group was obtained.

In the same manner as in Example 1, alphabet letters and images were recorded on the recording sheet using an inkjet printer in seven display colors, and then irradiated with light using an ultraviolet printing machine and washed with water to obtain a relief image of the non-image area. Ta.

Further, the recording sheet on which the relief image was formed was immersed in the following dye aqueous solution for 2 minutes, washed with water, and dried to obtain a relief image in which the unprocessed image portion was dyed red.

Composition of aqueous dye solution Parts by weight Kayacryl Red GL 2.5 Ethylene Glycol 10.0 Water 90 When this recording sheet with a relief image dyed in red was projected with an overhead projector, clear white letters with a red background and A projection of the image was obtained on a screen and was suitable as a transparency film.

As is clear from the above embodiments, the method of the present invention, which forms a relief image by printing or printing using an inkjet recording method and developing with water, can be used for plate making, drafting, proofing films, and electrical circuit board checks. It was confirmed that it has the advantage of being able to be used in a variety of applications such as film and OHP film.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an untreated recording sheet, Fig. 2 is an explanatory cross-sectional view of the recording sheet shown in Fig. 1 after being printed or drawn with water-based ink using the inkjet method and further irradiated with light. FIG. 2 is an explanatory cross-sectional view of a relief image recording sheet obtained by washing the recording sheet of FIG. 2 with water to remove an ink portion. In the figure, A...Untreated recording sheet, B...Recording sheet with ink drawn and light irradiated, C...Relief image recording sheet with ink areas removed by washing, A...Recording layer, B...Base material, 1 , 2, 3, 4... portion on which ink particles were placed, 5, 6, 7, 8... substrate surface exposed by washing and removal.

Claims (1)

[Claims] 1. A recording sheet having a recording layer made of a resin composition containing a water-developable photosensitive resin as a main component,
Printing or drawing is performed using an inkjet recording method that uses water-based ink, and after the water-based ink swells the printed or drawn portion of the recording layer to reduce photocurability, the entire surface of the recording sheet is irradiated with light. A relief image of the non-image area is created by making the non-image area to which ink is not attached to water insoluble by photo-curing, and then washing away the image area on which the aqueous ink is not photo-cured by washing with water. Characteristic method for forming relief images.