JPH0337655A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance electrophotographic characteristics and sensitivity by using as a resin binder a vinyl chloride-vinylidene chloride copolymer for an electric charge generating layer. CONSTITUTION:The charge generating layer 12 is formed on a conductive substrate 11 made of aluminum, copper, stainless steel, or the like by coating the substrate 11 with a coating fluid prepared by mixing an organic charge generating and the binder resin, such as polyester or polymethyl methacrylate, in an organic solvent. The photosensitive body to be used for a printer contains as the charge generating material a phthalocyanine derivative having an absorption peak in the infrared region, and that for a copying machine contains as the charge generating material an azo type compound having an absorption peak in the visible ray region. A charge transfer layer 13 is formed on the layer 12 by coating the layer 12 with a coating fluid prepared by dissolving an organic charge transfer material, such as pyrazoline or hydrazone, and a binder resin, such as polycarbonate, in an organic solvent, thus permitting electrophotographic characteristics and sensitivity to be enhanced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more specifically, a negative corona charger comprising a charge generation layer and a charge transport layer made of an organic material on a conductive substrate. The present invention relates to a resin binder used in a charge generation layer in a laminated type electrophotographic photoreceptor using a positive corona charging method or a positive corona charging method.

[Conventional technology]

Conventionally, photosensitive materials for electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) include inorganic photoconductive substances such as selenium or selenium alloys, or inorganic photoconductive substances such as zinc oxide or cadmium sulfide dispersed in a resin binder. organic photoconductive materials such as poly-N-vinylcarbazole or polyvinylanthracene, organic photoconductive materials such as phthalocyanine compounds or biasdi compounds, or these organic photoconductive materials dispersed in a resin binder. Things are being used. In addition, a photoreceptor must have the function of retaining surface charge in the dark and the function of receiving light and transporting the charge, but so-called single-layer photoreceptors have both these functions in one layer. There is a so-called laminated photoreceptor in which functionally separated layers are laminated, including a layer that mainly contributes to charge generation, and a layer that contributes to surface charge retention in the dark and charge transport during light reception. For example, the Carlson method is applied to image formation by electrophotography using these photoreceptors. Image formation in this method involves charging the photoconductor in a dark place by corona discharge, forming electrostatic latent images such as letters and pictures on the document by exposing the surface of the charged photoconductor, and This is done by developing a latent image with toner, transferring the developed toner image to a support such as paper, and fixing it. After the toner image has been transferred, the photoreceptor is subjected to static neutralization, removal of residual toner, photostatic static elimination, etc. Subject to reuse.

In recent years, multilayer photoreceptors using organic materials have been put into practical use due to their advantages such as flexibility, thermal stability, and film formability. For example, BoIJ-N-vinylcarbazole and 2.4
．． 'l-) dinitrofluorene 9-one (described in U.S. Pat. No. 3,484,237), a photoreceptor whose main component is an organic pigment <*described in Japanese Patent Publication No. 47-37543>, a photoreceptor made of dye and resin. A photoreceptor containing a eutectic complex as a main component (described in JP-A-47-10785), etc.

[Problem to be solved by the invention]

As mentioned above, photoreceptors made of organic materials have many advantages that photoreceptors made of inorganic materials do not have, but one problem is that a photoreceptor that fully satisfies all the characteristics required of a photoreceptor has not yet been obtained. At present, there is a particular problem with photosensitivity.

An object of the present invention is to solve the above-mentioned problems and provide a highly sensitive photoreceptor for printers and copying machines.

[Means to solve the problem]

According to the present invention, the above problem can be solved by using a photoreceptor comprising a charge generation layer and a charge transport layer made of an organic material on a conductive substrate, in which the resin binder used in the charge generation layer is vinyl chloride resin and vinylidene chloride. This problem can be solved by using a photoreceptor that is a copolymer with a resin.

[Effect]

In order to solve the above problems, the present inventors have carried out intensive evaluation studies on various resin binders, and as a result of conducting numerous experiments, the above-mentioned vinyl chloride resin and chloride Using a copolymer with vinylidene resin as the resin binder of the charge generation layer
discovered that it is extremely effective in improving electrophotographic properties,
A highly sensitive photoreceptor has been obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are schematic cross-sectional views of structures of different embodiments of a photoreceptor according to the present invention.

A photoreceptor having the structure shown in FIG. 1 is normally used in a negative corona charging system. First, a charge generation layer 12 is formed on a conductive substrate 11 made of aluminum, copper, stainless steel, or the like.

The charge generation layer 12 is formed by applying a material prepared by mixing an organic charge generation substance and a resin binder such as polyester or polymethyl methacrylate in an organic solvent by a dip method, a spray method, or the like. As charge-generating substances, phthalocyanine compounds having an absorption peak in the infrared light region are used in photoconductors for printers, and azo compounds having an absorption peak in the visible light region are used in photoconductors for copying machines. It will be done. Next, on this charge generation layer 12, a material in which an organic charge transport substance such as a pyrazoline compound or a hydrazone compound and a resin binder such as polycarbonate are uniformly dissolved in an organic solvent is similarly applied to form a charge transport layer 13. Form.

The photoreceptor having the structure shown in FIG.
Charge transport layer 22. A charge generation layer 23 is coated and formed in this order, and a coating layer 24 is further formed on top of it using an organic material such as polyester or polyamide for the purpose of protecting the charge generation layer 23. Usually, a positive corona charging method is used. used in In this case, the conductive substrate material, the charge generation layer material and the charge transport layer material are approximately the same as those of the negative corona charging type photoreceptor shown in FIG.

Specific examples will be described below.

Example 1 1 part by weight of X-type phthalocyanine as a charge generating substance and 1 part by weight of a copolymer resin of vinyl chloride resin and vinylidene chloride resin as a resin binder were mixed with 200 parts by weight of dichloromethane, and kneaded in a mixer for 3 hours. A coating solution for the charge generation layer was prepared. At that time, the composition of vinyl chloride resin and vinylidene chloride resin in this copolymer resin was changed as appropriate over the range of lO:0 to 0:10. Next, 1-phenyl-3-(p-diethylaminostyryl)-5-(
varadiethylaminophenyl)-2-pyrazoline (AS
PP>1 part by weight, polycarbonate resin as resin binder (trade name Panlite L-1225: manufactured by Teijin Kabo)
1 part by weight was dissolved in 6 parts by weight of dichloromethane to prepare a coating liquid for a charge transport layer. Next, a charge generation layer (1 .mu.m) and a charge transport layer (15 .mu.m) were sequentially coated on an aluminum substrate using the above coating solution to prepare a negatively charged photoreceptor.

Comparative Example 1 A photoreceptor was produced in the same manner as in Example 1, except that the resin binder for the charge generation layer was changed to a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.).

Example 2 In Example 1, the charge transport substance was p-diethylaminobenzaldehyde-diphenylhydrazone (ABPH>
A photoreceptor was produced in the same manner as in Example 1 except that the following was changed.

Comparative Example 2 A photoreceptor was produced in the same manner as in Example 2, except that the resin binder for the charge generation layer was changed to a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.).

The electrophotographic characteristics of the thus obtained negative corona charging type photoreceptor for printers were measured using an electrostatic recording paper tester rSP-428J manufactured by Kawaguchi Electric.

The surface potential V, (volt) of the photoreceptor is -6.0k in the dark.
This is the initial surface potential when the surface of the photoreceptor is negatively charged by corona discharge of V for 10 seconds, and the surface potential of the photoreceptor Va ( volts), and then irradiate the surface of the photoreceptor with monochromatic light (780 nm) with an illuminance of 1 μW to find the time (seconds) it takes for V to be halved, which is the halved exposure amount E I/2
(μJ/cIll). Further, the surface potential when the surface of the photoreceptor was irradiated with 1 μW monochromatic light for 10 seconds was defined as the residual potential V (volt).

The measurement results are shown in Tables 1 and 2, respectively.

As shown in Tables 1 and 2, in Examples 1 and 2, by setting the composition ratio of vinyl chloride-vinylidene chloride copolymer in the range of 1:9 to 420, Compared to Comparative Examples 1 and 2, the half-decrease exposure amount was significantly improved, and the superiority of the resin binder of the present invention is clear.

Example 3 6 parts by weight of chlorodiane blue as a charge generating substance, P
Ii As a fat binder, 4 parts by weight of a copolymer resin of vinyl chloride resin and vinylidene chloride resin were mixed with 4 parts by weight of dichloromethane.
00 parts by weight and kneaded in a mixer for 3 hours to prepare a coating solution, thereby producing a coating solution for the charge generation layer. At that time, the composition ratio of vinyl chloride resin and vinylidene chloride resin in this copolymer resin was changed as appropriate over the range of lO:0 to 0:10. Next, 1-
Phenyl-3-(p-diethylaminostyryl)-5-
(varadiethylaminophenyl)-2-pyrazoline (A
A coating liquid for a charge transport layer was prepared by dissolving 1 part N of SPP) and 1 part by weight of a polycarbonate resin (trade name Panlite L-1225, manufactured by Teijin Chemical Co., Ltd.) as a resin binder in 6 parts by weight of dichloromethane. Next, a charge generation layer (1 .mu.m) and a charge transport layer (15 .mu.m) were coated in this order on an aluminum substrate using the above coating solution to prepare a negatively charged photoreceptor.

Comparative Example 3 A photoreceptor was produced in the same manner as in Example 3, except that the resin binder for the charge generation layer was changed to a polyester resin (trade name: Vylon 200, manufactured by Toyobo).

Example 4 In Example 3, the charge transport material was p-diethylaminobenzaldehyde-diphenylhydrazone (A B P
A photoreceptor was produced in the same manner as in Example 3 except that H) was used.

Comparative Example 4 A photoreceptor was produced in the same manner as in Example 4, except that the resin binder for the charge generation layer was changed to a polyester resin (trade name: Vylon 200: Toyo Boseki).

The electrophotographic characteristics of the thus obtained negative corona charging type photoreceptor for copying machines were measured using an electrostatic recording paper tester r manufactured by Kawaguchi Electric.
Measured using SP-428J.

The surface potential VS (volts) of the photoreceptor is -6.0k in the dark.
This is the initial surface potential when the surface of the photoreceptor is negatively charged by performing a corona discharge of V for 10 seconds, and the surface potential of the photoreceptor is Vd ( Then, the photoreceptor surface was irradiated with white light with an illuminance of 21 ux, and the time (seconds) until V was halved was determined, which was determined as the half-Ia exposure amount E+z2 (1 ux·sec). Further, the surface potential when the surface of the photoreceptor was irradiated with 2&uX white light for 10 seconds was defined as the residual potential V (volt).

The measurement results are shown in Tables 3 and 4, respectively.

Table 4 As shown in Tables 3 and 4, in Examples 3 and 4, the composition ratio of the vinyl chloride-vinylidene chloride copolymer was set in the range of 1:9 to 4:6. Compared to Examples 3 and 4, the half-decrease exposure amount was significantly improved, and the superiority of the resin binder of the present invention is clear.

Example 5 1 part by weight of 1-phenyl-3-(p-diethylaminostyryl)-5-(para-diethylaminophenyl)-2-pyrazoline (A S P P) was used as the charge transport substance, and polycarbonate resin (trade name: Panly) was used as the resin binder. ) L-1225 (manufactured by Teijin Kasei) was dissolved in 6 parts by weight of dichloromethane to prepare a coating liquid for a charge transport layer.

Next, 6 parts by weight of chlorodia ampule as a charge-generating substance and 4 parts by weight of a copolymer resin of vinyl chloride resin and vinylidene chloride resin as a resin binder were mixed with 400 parts by weight of dichloromethane, and kneaded in a mixer for 3 hours. A coating liquid was prepared by performing the following steps to prepare a coating liquid for charge generation. At that time, the composition ratio of vinyl chloride resin and vinylidene chloride resin in this copolymer resin was changed as appropriate over the range of 10:0 to 0:10.

Furthermore, 6 parts by weight of acrylic modified silicone resin was dissolved in 100 parts by weight of ethanol to prepare a coating liquid for the coating layer.

Next, a charge transport layer (15 μm), a charge generation layer (1 μm), and a coating layer (1 μm) were coated on the aluminum substrate with the above coating solution.
A positively charged photoreceptor was prepared in the order of step m).

Comparative Example 5 A photoreceptor was produced in the same manner as in Example 5, except that the resin binder for the charge generation layer was changed to a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.).

Example 6 In Example 5, the charge transport material was p-diethylaminobenzaldehyde-diphenylhydrazone (ABPH).
A photoreceptor was produced in the same manner as in Example 5, except that .

Comparative Example 6 A photoreceptor was produced in the same manner as in Example 6, except that the resin binder for the charge generation layer was changed to a polyester resin (trade name: Vylon 200, manufactured by Toyobo).

The electrophotographic characteristics of the positive corona charging type photoreceptor for copying machines obtained in this way were measured using an electrostatic recording paper tester r manufactured by Kawaguchi Electric.
Measured using SP-428J.

The surface potential VS (volt) of the photoreceptor is +6.0k in the dark.
This is the initial surface potential when the surface of the photoreceptor is positively charged by performing a corona discharge of V for 10 seconds, and then the surface potential of the photoreceptor is V when the corona discharge is stopped and the photoreceptor is held in the dark for 2 seconds. (volts), and then irradiate the surface of the photoreceptor with white light with an illuminance of 21u x to find the time (seconds) it takes for vd to be halved.Half exposure amount E + z2 (#ux 1 second)
And so. Further, the surface potential when the surface of the photoreceptor was irradiated with 21 ux white light for 10 seconds was defined as the residual potential V (volt).

The measurement results are shown in Tables 5 and 6, respectively.

As seen in Tables 5 and 6, in Examples 5 and 6, by setting the composition ratio of vinyl chloride-vinylidene chloride copolymer in the range of 1:9 to 4:6, Comparative Examples 5 and 6 The half-decrease exposure amount was significantly improved compared to Sample No. 6, and the superiority of the resin binder of the present invention is clear.

〔Effect of the invention〕

According to this invention, in a multilayer photoreceptor using an organic material, a highly sensitive photoreceptor is obtained by using a copolymer of vinyl chloride resin and vinylidene chloride resin as a resin binder constituting the charge generation layer. be able to. The present invention is effective for both negative corona charging type and positive corona charging type photoreceptors in which the charge generation layer and the charge transport layer are stacked in different order. Further, by appropriately selecting and using a charge generating substance used in the charge generating layer, a highly sensitive photoreceptor suitable for various electrophotographic devices such as printers and copying machines can be obtained.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic cross-sectional views of structures of different embodiments of a photoreceptor according to the present invention. 11, 21 Conductive substrate, 12.23 Charge generation layer, 13° 22 Charge transport layer, 24 Covering layer. 2nd Figure 13 Charge transport layer 12 Charge generation layer 11 Conductive substrate 24 Covering layer 23 Charge generation layer 22 Charge transport layer 21 Conductive substrate

Claims (1)

[Claims] 1) In an electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer made of an organic material on a conductive substrate, the resin binder used for the charge generation layer is a copolymer of vinyl chloride resin and vinylidene chloride resin. An electrophotographic photoreceptor characterized by: