JPH046945B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic method with excellent transfer properties.

There are two main types of toner used as a developer in electrophotography: dry toner and wet toner.
When a photoreceptor is used repeatedly, it is necessary to efficiently transfer the toner on the photoreceptor to a transfer target such as paper. When transferring insulating dry toner to paper, an electrostatic latent image is developed, the paper is brought into close contact with the surface of the photoreceptor on which the toner has adhered in image form, and a direct current corona of the opposite polarity to the charge of the toner is applied from the back of the paper. Many copying machines and the like employ a transfer method called an electrostatic transfer method, which uses electrical discharge to attract and transfer toner onto paper.

Although this method uses a simple device, the electrical resistance of the transfer paper must be 10 ⁹ to 10 ¹² Ωcm in order to properly retain the corona discharge charge applied from the back of the paper on the back of the paper and to prevent discharge during separation. It has the disadvantage that it is easily affected by environmental humidity, moisture content in paper, etc. Furthermore, this electrostatic transfer method is not only limited to the electrical resistance of the transfer target within the above range, but also applies to materials that do not have the ability to retain corona discharge charges, such as metals, materials laminated with metal foil and paper, and metal-deposited films, or those that have attached corona discharges. Transfer of charges to materials that shield the electric field cannot be performed. Furthermore, even if the electrical resistance is within the above range, if the thickness of the transfer target is large, the electric field of the corona discharge charge from the back side will be weak on the surface, resulting in poor or impossible transfer.

These drawbacks are common to electrostatic transfer methods other than corona transfer, and they occur in both dry toner and wet toner as long as toner is electrostatically transferred.

As a means to overcome the above-mentioned drawbacks, there is a physical transfer method that does not use electrical force for transfer, and an example of such a method is an adhesive transfer method. In this method, paper coated on one side with a pressure-sensitive adhesive is brought into contact with the toner image, pressure is applied with a soft roller to bring the toner image into close contact, and the image is then peeled off to transfer the toner image.

This method differs from the electrostatic transfer method described above,
This method has the advantage of being able to perform transfer regardless of the electrical properties of the object to be transferred, since no electrical force is used. However, if the photoreceptor and the transfer target are brought into sufficient contact by applying pressure or other means in order to complete the transfer, it becomes difficult to peel and separate the photoreceptor and the transfer target, and the pressure-sensitive adhesive becomes photosensitive during peeling and separation. It may remain on the surface of the body, or conversely, a part of the photoconductive photosensitive layer may peel off, and the force required for peeling and separation may be large enough to damage or deform the photoreceptor and/or the transfer target. There is a disadvantage that it becomes impossible to use the photoreceptor repeatedly, or that the photoreceptor becomes more contaminated with repeated use.

Another method of physical transfer is the use of thermoplastic toner. In this method, the transfer target is brought into close contact with the photosensitive surface and pressure is applied, or heat and pressure are applied to soften the toner and soak it into the transfer target, or after the toner is wetted with the transfer target, the transfer target is simply peeled off. After separation, cooling, or pressure relief, toner transfer is performed by peeling and separating. In this method, the quality of the transfer depends on the balance between the adhesion force of the toner to the photoconductor, the adhesion force to the transfer target, the cohesive force of the toner itself, the cohesive force of the photoconductor itself, and the cohesive force of the transfer target itself. However, since there is usually not a large difference in the adhesion between the photoreceptor and the toner and the adhesion between the toner and the transfer target, there is a disadvantage that a large amount of toner remains on the surface of the photoreceptor after transfer. remains in good adhesion to the photoreceptor due to pressure, heat, etc.
There is a serious drawback that it is difficult to completely remove even if cleaning is performed, and that the surface of the photoreceptor is often scratched if an attempt is made to remove it forcibly.

The present inventors have arrived at the present invention as a result of intensive research to improve the above-mentioned problems. A step of applying a corona discharge charge to the surface of an electrophotographic photoreceptor comprising a photoconductive photosensitive layer having a photoconductive layer provided on a conductive substrate, a step of exposing to light in a pattern, a step of developing with a toner, and a step for electrophotography after development. This method is characterized by performing a step of applying pressure to transfer the toner on the surface of the photoreceptor onto a transfer target.

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 material of the photosensitive layer 2 is 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. In addition to inorganic materials such as , organic photoreceptors such as poly-N-vinylcarbazole, and functionally separated photoreceptors with multilayer structures, any known electrophotographic photoreceptor that exhibits photoconductivity can be used. and its installation method,
The thickness etc. may be determined according to known conditions.

The present invention provides an aminoalkyd resin layer on this photoconductive photosensitive layer. The releasability of the aminoalkyd resin layer is also affected by the smoothness of the surface of the photoconductive photosensitive layer; if the surface is smooth, even a thin aminoalkyd resin layer will have sufficient releasability, whereas if the surface is rough, the aminoalkyd resin layer can be removed. It needs to be thick. However, since making the amino alkyd resin layer thicker than necessary causes deterioration in resolution, the thickness of the layer is preferably 0.01 to 5 .mu.m. From the above point of view, especially in the case of a binder-dispersed photoreceptor, it is preferable to keep the surface smooth. Furthermore, a primer treatment may be applied to improve the adhesion between the photoconductive photosensitive layer and the aminoalkyd resin layer.

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 ethoxysilane, vinyltris(t-butylperoxy)silane alone or mixtures thereof, and partial hydrolysates or cohydrolysates thereof; tetraisopropyl titanate, tetrabutyl titanate, tetraisobutyl titanate, tetra- Titanium orthoesters such as 2-ethylhexyl titanate, titanium chelates such as titanium acetylacetonate and triethanolamine titanate, titanium acylates such as polyhydroxytitanium stearate and polyisopropoxytitanium stearate, and organic titanium compounds such as those listed above. or mixtures thereof; aluminum alcoholates such as aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum chelate compounds such as ethyl acetoacetate aluminum diisopropylate, the above organoaluminum compounds alone or mixtures thereof; others and mixtures of the above silanes and 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 physical 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.

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. The surface of the electrophotographic photoreceptor developed with the above-mentioned toner is heated by using a pressure roll 8 and an appropriate means such as heating the roll or using a heater on the transfer object shown by 9 in the figure. The temporary toner is adhered to the object to be transferred, and then the object to be transferred is peeled off.

Any material can be selected as the material to be transferred 9 as long as the material has a surface condition that allows the toner to come into close contact with the surface of the electrophotographic photoreceptor, and the shape may be sheet-like, plate-like, thick plate-like, or cylindrical. It is possible to do so. Examples of specific materials include metals such as iron, aluminum, copper, and zinc, various alloys, and inorganic materials such as glass; wood, leather, natural rubber, paper, and cloth;
Hydrocarbon plastics such as polyethylene and polystyrene, polar vinyl plastics such as ABS resin, linear plastics such as polyamide, formaldehyde plastics such as phenol resin, crosslinked plastics such as unsaturated polyester, acetic acid These include polymeric materials such as cellulose-based plastics such as cellulose, and materials commonly referred to as rubber. A composite of the above materials can also be used. In addition to the pressure rolls indicated by 8 in Fig. 5, a flat pressure type press machine can also be used, and the pressure thereof is 1Kg/cm ² to 200Kg/cm ² .
The heating temperature is approximately 30-250°C.

According to the electrophotographic photoreceptor of the present invention that can be produced as described above, the releasability of the photoreceptor surface is high;
The toner on the electrophotographic photoreceptor can be completely transferred without damaging the electrophotographic photoreceptor and the transfer target.

In addition, when using a pressure fixing toner, conventionally, the toner is transferred in two steps: electrostatically transferring it from the electrophotographic photoreceptor to the transfer object, and then fixing the toner on the transfer object by applying pressure with a pressure roll. By performing physical transfer using the electrophotographic photoreceptor of the present invention, fixing can be performed simultaneously when transferring the toner from the photoreceptor to the transfer target, instead of transferring and fixing, which eliminates static electricity. A major advantage is that a corona discharge device for transfer is not required.

Furthermore, according to the present invention, since there is almost no deterioration in charging characteristics due to the installation of the aminoalkyd resin layer, it is possible to use the same electrophotographic process as used for the electrophotographic photoreceptor before installing the aminoalkyd resin layer. It has the great advantage of not requiring any special processes.

The present invention will be explained in more detail below using Examples.

Example 1 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 non-volatile content of 4:1, and mixed with toluene. After diluting the non-volatile content to 30% and thoroughly dispersing it with ultrasonic waves for 10 minutes, it was coated on an aluminum plate so that the coating film after drying had a thickness of 15μ and dried at 150°C for 3 hours to form a photoconductive layer.

Next, amino alkyd resin (Dainippon Ink & Chemicals, Betsukosol M-7606-55MV) was applied onto this photoconductive layer so that the dry film thickness was 3 μm, and after drying, it was heated at 150°C for 2 hours. This was then cured to obtain a photoreceptor having an easily peelable layer.

This photoreceptor was negatively charged in a normal process, and after pattern exposure, development was performed using a dry developer (Iwasaki Tsushinki, Carrier A for Elephax, Developer P-1), and a clear image with no background smear was obtained. . After attaching an aluminum plate to this object, we heated it from behind to 100℃ and applied a pressure of 100Kg/cm ² , then cooled it, released the pressure, and separated the aluminum plate, and the toner was completely absorbed into the aluminum plate. There was no toner remaining on the surface of the photoreceptor.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a cross section of an electrophotographic photoreceptor according to the present invention. FIGS. 2 to 5 are diagrams for explaining the electrophotographic method of the present invention. . DESCRIPTION OF SYMBOLS 1... Substrate, 2... Photoconductive photosensitive layer, 3... Amino alkyd resin layer, 4... Corona discharge device,
5... Corona discharge charge, 6... Light, 7... Toner, 8... Pressure roll, 9... Transferred object.

Claims (1)

[Claims] 1. A step of applying corona discharge charge to the surface of an electrophotographic photoreceptor, which is formed by providing a photoconductive photosensitive layer having an easily peelable layer made of an amino alkyd resin with a film thickness of 0.01 to 5 μm on the surface on a conductive substrate, in a patterned manner. An electrophotographic method comprising the steps of exposing to light, developing with toner, and applying pressure to transfer the toner on the surface of an electrophotographic photoreceptor after development onto a transfer target.