JPH0447833B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color image forming method, and more particularly to a method that can easily form color images on various transfer objects regardless of the material of the transfer object.

2. Description of the Related Art Conventionally, when forming an image using an electrophotographic method, a method using electrical force or a method using physical force is well known as a method for transferring toner.

As a method using electric force, an electrostatic transfer method is known in which a direct current corona discharge having a polarity opposite to the charge of the toner is generated from the back side of the transfer object to attract and transfer the toner to the transfer object. The electrostatic transfer method has a simple device and is a method used in ordinary electrophotographic copying machines, but there is a problem that the toner on the photoreceptor is not completely transferred, resulting in a decrease in image density. The drawback is that cleaning is required and the surface of the photoreceptor is easily damaged during cleaning. The reason for this low transfer efficiency is thought to be that electrostatic attraction and physical interaction force between the photoreceptor and the toner inhibit transfer. In addition, this electrostatic transfer method requires that the electrical resistance of the transferred object be within the range of 10 ⁹ to ^{10 12} Ωcm, which has the disadvantage that it is susceptible to the influence of the surrounding environment. There are also limits to size. In particular, a major drawback is that the material of the transfer target is limited.

As a method to overcome these drawbacks of the method using electric force, there is an adhesive transfer method that uses physical force to perform transfer using an adhesive. This method is carried out by applying a pressure-sensitive adhesive to the surface of the object to be transferred, and the toner on the photoreceptor is brought into contact with the adhesive-coated surface and transferred to the object. Adhesive transfer methods have advantages such as being unaffected by the material and thickness of the material to be transferred and having high toner transfer efficiency, but on the other hand, the adhesive may remain on the photoreceptor, or conversely, the adhesive may remain on the photoreceptor. There are drawbacks such as damage caused by peeling off the photoreceptor, or in areas where there is no toner, the photoreceptor and the transfer target directly adhere firmly to each other, resulting in damage or deformation of either of them when peeled off. Due to these drawbacks, the adhesive transfer method has not been put into practical use so far, even though the transfer itself is stable and suitable for forming color images.

Background smudges and low transfer efficiency are not so much of a problem when copying documents, etc., but for the purpose of obtaining color images, background smudges are observed as color turbidity, and poor transfer efficiency, that is, instability, is a problem in color tone. It is sensitively observed as a change in

In view of the drawbacks of the adhesive transfer method described above, the present inventors conducted research and found that even if a thin layer of easily peelable material is provided on the surface of the photoreceptor, the performance of the electrophotographic photoreceptor is not adversely affected, and on the contrary, it is easy to remove. The present invention was developed based on the discovery that by providing a removable material layer on the surface of a photoreceptor, background smudges during development can be reduced and that the resulting smudges can be easily removed.

That is, in the present invention, a latent image is formed in a pattern by charging an electrophotographic photoreceptor and exposing it to pattern light according to color separation information, and then developing it with toner, and applying the resulting image to another substrate. The gist of the present invention is a color image forming method in which a color image is transferred to a transfer member via an adhesive, and the method is characterized in that an electrophotographic photoreceptor having an easily peelable material layer provided on its surface is used. It is something.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 shows a cross section of an electrophotographic photoreceptor according to the present invention. The substrate 1 is a substrate whose surface is electrically conductive at least, and in addition to a material that is entirely electrically conductive such as metal, the surface of an insulating material such as paper, glass, or plastic is subjected to electrical conductive treatment or a electrically conductive material is laminated thereon. materials can be used. In either case, it is desirable that the structure is such that the ground electrode can be easily removed from the photoconductive photosensitive layer, and it may be in the form of a plate or a cylinder.

The materials of the photoconductive photosensitive layer 2 are amorphous selenium, a composition of cadmium sulfide and a resin binder, a composition of zinc oxide and a resin binder, amorphous silicon, cadmium sulfide, a composition of cadmium sulfide, cadmium carbonate and a resin binder. Any known electrophotographic photoreceptor that exhibits photoconductivity, such as organic photoreceptors such as poly-N-vinyl carbazole, and functionally separated photoreceptors with a multilayer structure, as well as inorganic materials such as can also be used, its installation method,
The thickness etc. may be determined according to known conditions.

The material of the easily peelable material layer 3 may be any material that has peelability, such as silicone resin, fluororesin, aminoalkyd resin,
Casein etc. can be used. To explain silicone resins as an example, addition-type or condensation-type silicone rubber for release paper is cured with a curing catalyst, -
Various silicone resins can be cured by known methods, such as silicone oil containing SiH cured with an addition-type curing catalyst such as chloroplatinic acid, as well as silicone raw rubber, silicone rubber for release paper, etc., cured with peroxide. You can use what you have. When using the above-mentioned silicone resin, it is sufficient to dilute the silicone resin stock solution to a concentration that is easy to apply, add a curing agent, and then apply it on the photoconductive photosensitive layer and cure it, and any method that allows uniform application may be used. The coating may be applied by wire bar coating, spin coating, roll coating, spray coating, dip coating, or the like.
Other easily peelable materials that can be used include fluorine resins, especially polytetrafluoroethylene dispersion or enamel. The releasability of the easily removable material layer is also affected by the smoothness of the surface of the photoconductive photosensitive layer; if the surface is smooth, even a thin removable material layer will show sufficient removability, but if the surface is rough, it will show sufficient removability. It is necessary to thicken the easily peelable material layer.
However, since making the easily peelable material layer thicker than necessary causes deterioration in resolution, the thickness of the layer is preferably 0.01 to 5 μm. From the above point of view, especially in the case of binder-dispersed photoreceptors,
It is preferable to keep the surface smooth. Further, in order to improve the adhesion between the photoconductive photosensitive layer and the easily peelable material layer, a primer treatment may be performed.

In this case, the primers include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N
-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane Silanes such as methoxysilane, vinyltris(t-butylperoxy)silane alone or mixtures thereof, and partial hydrolysates or cohydrolysates thereof; tetraisopropyl titanate, tetrabutyl titanate, tetra-2-
titanium orthoesters such as ethylhexyl titanate, titanium chelates such as titanium acetylacetonate, triethanolamine titanate,
Titanium acylates such as polyhydroxy titanium stearate and polyisopropoxy titanium stearate, organic titanium compounds such as those mentioned above alone or mixtures thereof; aluminum isopropylate,
Aluminum alcoholates such as monosec-butoxyaluminum diisopropylate, aluminum chelate compounds such as ethyl acetoacetate aluminum diisopropylate, the above organoaluminum compounds alone or mixtures thereof; other organometallic compounds; the above silanes and Examples include mixtures of organometallic compounds.

The application method is to dilute it to an appropriate concentration as necessary.
Any method capable of uniform coating such as wire bar coating, spin coating, roll coating, spray coating, or dip coating may be used.

An example of adhesive transfer after forming a toner image using the electrophotographic photoreceptor of the present invention obtained as described above is shown in FIGS. 2 to 5. Although the charge is shown as negative for convenience of explanation, it goes without saying that the chargeability is determined by the type of photoconductive photosensitive layer used.

In the electrophotographic photoreceptor according to the present invention, for example, a second
As shown in the figure, the corona discharge electrode is moved in the direction of the arrow by the corona discharge device 4 to apply a corona discharge charge, and then exposed to light in a pattern as shown in FIG. 3 to form an electrostatic latent image. After developing the electrophotographic photoreceptor on which the electrostatic latent image shown in FIG. Transfer can be carried out by using a pressure roll 8 on a transfer object indicated by 9 in the figure and directly pressing the transfer object 9 onto a photoconductor having toner 7 via an adhesive 10. Note that a commercially available adhesive film or adhesive paper may be used without applying an adhesive to the object to be transferred prior to transfer. Alternatively, the adhesive 10 may be applied onto the photoreceptor to which the toner has been temporarily attached, and then the two may be pressed together to transfer the image to the transfer object. Furthermore, using yellow, magenta, and cyan color toners and, if necessary, black toner, separate color images of each of the above colors are created, and the images are transferred onto transparent films and overlaid. Alternatively, it is possible to create an image in which each color is superimposed on a photosensitive plate and transfer it to the transfer object all at once. As the adhesive, a known adhesive can be used, and the adhesive can be applied by a known method such as a spray method, a coat coating method, or a roll coating method.

According to the above-described method of the present invention, a high-quality image can be obtained because there is no background smudge and the transfer efficiency is high. Transfer can be performed regardless of the material of the transfer target, and the charging property due to the installation of an easily peelable material layer. This has the advantage that, except for the transfer step, it is possible to use electrophotographic processes and equipment before installing the easily peelable material layer, since there is almost no deterioration caused by the type of toner used. Background stains can also be removed by applying vibration from behind the photoreceptor, blowing air from the surface, or by brushing with a magnetic brush that does not contain toner. When using a wet toner, it can be removed by rinsing with a linear petroleum solvent or the like.

Examples are given below to explain the present invention more specifically. In the following, "parts" indicate parts by weight.

Example 1 Partially saponified ethylene vinyl acetate copolymer......10 parts (manufactured by Takeda Pharmaceutical Industries, Ltd., Dumilan C-2270) Carbon black......10 parts (manufactured by Mitsubishi Chemical Industries, Ltd., Carbon Diamond #30) Cobalt naphthenate......40 Parts Toluene...100 parts After stirring and dissolving the solution in the above ratio at 80°C, it was rapidly cooled to 10°C while stirring, and 300 parts of a linear petroleum solvent (Isopar H, manufactured by Exxon Chemical) was added. After decantation, 300 parts of the above petroleum solvent was added to produce a black toner. Using the same procedure, instead of carbon black, Sumikaprint Blue GNOPP (manufactured by Sumitomo Chemical), Seika First Carmine-1480 (manufactured by Dainichiseika Chemical Industries), or Chromophine Yellow was used as the coloring agent.
The same amount of AF1100 (manufactured by Dainichiseika Chemical Industry Co., Ltd.) was added to a solution having the above composition to obtain wet toners of cyan, magenta, and yellow. Photoreceptors were prepared as follows.

Zinc oxide (manufactured by Sakai Chemical Industries, Ltd., SAZEX #2000) with 0.01% rose bengal adsorbed and silicone varnish (manufactured by Shin-Etsu Chemical Industries, Ltd., KR211) were mixed at a ratio of 4:1 in terms of non-volatile content, and the non-volatile content was reduced to 30% with toluene. % and was well dispersed using ultrasonic waves for 10 minutes, and then coated on an aluminum plate so that the coating film after drying had a thickness of 15 μm, and dried at 150° C. for 3 hours to form a photoconductive layer. Next, a silicone resin for release paper (KS774, Shin-Etsu Chemical Co., Ltd.) with a curing agent (C-2, Shin-Etsu Chemical Co., Ltd.) was diluted to 3% with silicone oil (KF96L, Shin-Etsu Chemical Co., Ltd.). It was coated on the photoconductive layer so that the dry coating film had a thickness of 3 μm, and after drying, it was cured by heating at 150° C. for 2 hours to obtain a photoreceptor having an easily peelable layer. This photoreceptor is negatively charged in a normal process, and a yellow halftone plate obtained by color separation is adhered to it. After exposure in a pattern using a printer, plate development is performed using the yellow toner to ensure that there is no background smudge. After obtaining the image and drying it, a transparent adhesive film (manufactured by Fuji Paper Industries Co., Ltd.,
Fuji Clear) was adhered using a pressure roll, and then peeled off to transfer the yellow image. Next, a transparent adhesive film image was similarly transferred using a magenta plate and magenta toner. Transfer the cyan and black images in the same way and use these films.
A color image was obtained by laminating yellow, magenta, cyan, and black in the order of 100 μm thick polyester film while aligning the film. Black toner is a little more smudged than other toners, so
Before transfer, background stains were removed by rinsing with the petroleum solvent.

Example 2 Using dry color toner manufactured by Tokyo Ink instead of the trial toner, halftone images of each color were obtained on the photosensitive plate of Example 1 by the magnetic brush development method after being charged and exposed in the same manner. In the case of the dry toner, background smearing occurred compared to when using the prototype wet toner, but the smearing could be removed by rubbing 2 to 3 times with a magnetic brush that did not contain toner. or,
Dirt can also be removed by applying vibration from the back. A good color image was obtained by sequentially pasting this on coated paper using a pin system and heating it.

Example 3 A solution having the following composition was prepared using ZnO powder adsorbed with 0.15% rose bengal.

(0.2% Rose Bengal) ZnO...85 parts Silicone resin (Shin-Etsu Chemical Co., Ltd., KR-305)
...20 parts Ethyl cellosolve ...55 parts The liquid having the above composition was dispersed by ultrasonic waves for 30 minutes. After cooling, the mixture was filtered using a screen mesh, and 6 parts of an isocyanate curing agent (Coronate-2031, manufactured by Nippon Polyurethane) was added and mixed well. The above solution was applied to the aluminum foil surface of a sheet made by dry laminating 12 μm thick aluminum foil on a 100 μm thick polyester film to a thickness of 10 to 15 μm using a Whaler coating machine.After standing for 20 minutes, a solution with the following composition was applied as a primer. Prepared silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.,
KBM-403)...5 parts Tetrabutoxy titanate...5 parts Silicone oil (Shin-Etsu Chemical, KF96)
...90 parts were further coated with a Whaler coater and heated in an oven at 100°C for 20 minutes. Next, the following liquid composition was prepared as a release layer.

Silicone resin (Shin-Etsu Chemical, KS705F)
3-part silicone oil (manufactured by Shin-Etsu Chemical, KF96)
87 parts Catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., Cat.PS) 0.1 part This was applied to a sheet coated with ZnO and primer using a Whaler coating machine, and placed in an oven at 100°C for 1 part.
A photoreceptor was obtained by heating for a period of time.

After the obtained photoreceptor was negatively charged, it was mounted on a laser plotter manufactured by Cytecs, and a halftone image was directly drawn on it. After drawing, development was performed using the wet toner of Example 1, and a good color image was obtained in the same manner as in Example 1.

Example 4 A 100 μm thick transparent polyester film was spray coated with an acrylic adhesive (SK Dyne 1004, manufactured by Soken Chemical Co., Ltd.) diluted 4 times with a solvent of toluene/ethyl acetate = 1/1, and after drying, Example The black image on the photoreceptor obtained by method 1 was transferred in the same manner. Furthermore, the adhesive liquid was spray-coated onto the surface onto which the black image had been transferred, and after drying, the cyan image obtained by the method of Example 1 was transferred while adjusting the register. Similarly, magenta and yellow images were adhesively transferred, and finally the adhesive side was attached to coated paper.
This resulted in a color image that could be used as a proof.

Example 5 A silicone primer (manufactured by Shin-Etsu Chemical Co., Ltd., KBP41) was dip-coated on the surface of a cylindrical amorphous Se photoreceptor so that the coating thickness after drying was 0.1μ, and after drying,
After being left at room temperature for 1 day, silicone for release paper (KS705F, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied by dip coating so that the coating film after drying was 1 μm, and after drying, it was left at room temperature for 2 days.

After the photoreceptor thus obtained was positively corona charged, it was developed using a negatively charged dry color toner manufactured by Tokyo Ink Co., Ltd. according to the method of Example 2, and a color image was obtained in the same manner as in Example 2. Ta.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the electrophotographic photoreceptor used in the present invention, and FIGS. 2 to 6 are cross-sectional views showing each step of image formation using the electrophotographic photoreceptor of FIG. 1. 1...Support, 2...Photoconductive photosensitive layer, 3...
Peeling layer, 4...Corona charging device, 5...Charge, 6
...Light, 7...Toner, 8...Heat pressure roll, 9...
... Transferred object, 10... Adhesive.

Claims (1)

[Claims] 1 Electrophotographic photoreceptor is charged and exposed in a pattern according to color separation information to form a patterned latent image, then developed using toner, and the resulting image is adhered to other transfer objects. 1. A method for forming a color image in which an image is transferred through an agent, the method comprising using an electrophotographic photoreceptor having an easily peelable material layer on its surface.