JPH0243559A - electrophotographic photoreceptor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, in which an intermediate layer having the function of both an adhesive layer and a barrier layer is provided between an electrically conductive support and a photosensitive layer. The present invention relates to an electrophotographic photoreceptor.

[Conventional technology]

In general, in Carlson type electrophotographic photoreceptors, the stability of the dark area potential and bright area potential is important in forming a constant image density and smoothed image with background smudges when charging is repeated. There is.

For this reason, it has been proposed to provide a layer functioning as a barrier layer between the photosensitive layer and the support.

In addition, a layered structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed, but the charge generation layer is generally provided as an extremely thin layer, for example, with a thickness of about 0.5 μm. Defects, dirt, deposits, scratches, etc. on the surface of the support cause the thickness of the charge generation layer to be non-uniform. If the thickness of the charge generation layer is not uniform, uneven sensitivity will occur in the photoreceptor, so it is required that the charge generation layer be made as uniform as possible.

For this reason, it has been proposed to provide an intermediate layer between the charge generation layer and the support, which functions as a barrier layer and an adhesive layer.

Until now, polyamide (41F) was used between the photosensitive layer and the support.
+ JP-A-46-47344, JP-A-52-25638), polyester (JP-A-52-20836, JP-A-54-26738), polyurethane (JP-A-49-1
No. 0044, JP-A No. 53-89435), casein (
#Kokai No. 55-103556), polypeptide (JP-A-1
11853-48523)% polyvinyl alcohol (
% Kokai No. 100240/1983), polyvinylpyrrolidone (% Kokai No. 30936/1982), vinyl acetate-ethylene copolymer (Japanese Kokai No. 26141/1973), maleic anhydride ester polymer (Japanese Kokai No. 52/1982) 10138), polyvinyl butyral (% 1987-90639, JP 58-106549), quaternary ammonium salt-containing polymers (% JP 51-126149, JP 56-604)
No. 48), ethyl cellulose (% 1986-14356)
It is known to use an intermediate layer consisting of No. 4) or the like.

[Problem to be solved by the invention]

However, in electrophotographic photoreceptors using these materials as intermediate layers, the potential tends to change due to the influence of the temperature and humidity environment, and the barrier function decreases under high temperature and humidity, and the dark area potential decreases due to carrier injection from the support side. There was a drawback that the density of the copied image was reduced and the density of the copied image was reduced.

Furthermore, when such a photoreceptor is used in an electrophotographic printer that performs reversal development, there is a problem in that capri is likely to occur in images under high temperature and high humidity conditions.

In particular, in a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are sequentially laminated, the charge generation layer containing a high concentration of a charge generation substance is located on the intermediate layer, which causes an increase in carrier injection from the support side. Potential drop is more likely to occur, and even if the barrier function of the intermediate layer is slightly reduced, capri is more likely to occur in printers using a reversal development system.

Furthermore, photoreceptors using conventional materials for the intermediate layer tend to have an increase in bright area potential and a fluctuation in dark area potential when used repeatedly.Especially in low temperature and low humidity environments where the resistance of the intermediate layer increases, Due to the residual charge, the bright area potential increases significantly, and it has the disadvantage that copies with a constant image quality cannot be obtained when used continuously.

An object of the present invention is to provide an electrophotographic photoreceptor that can obtain a stable dark area potential against changes in temperature and humidity environment, and also to suppress increases in bright area potential and fluctuations in dark area potential even during repeated use. It is a trap to provide an electrophotographic photoreceptor with high quality.

[Means to solve the problem]

In the electrophotographic photoreceptor of the present invention, the intermediate layer between the conductive support and the photosensitive layer is a unit component [wherein R1 is a hydrogen atom or a methyl group, and A is an optional C1 to C6 alkylene group] and Y0#iR2
, R3 and R4 are an alkyl group, a phenyl group or a hapendyl group, and these may be substituted.〈B is a residue that forms a heterocycle together with N, and D forms a heterocycle together with N=C. is a residue), and Xo is an ion.

In the above polymer or copolymer used in the present invention, z
#i An alkylev group which may be substituted, and examples of substituents when substituted include a methyl group, a hydroxyl group, a methoxy group, a nitro group, a cyan group, and a halogen atom. Examples of substituents when R2, R3 and R4 are substituted include a hydroxyl group, a methoxy group, a nitro group, a cyano group, and the like. Also, as an example of Xe 0, halodane anion e 2e 2e
eNo, , Co3, SO4, CF, SO,
, CH, C00e'Ilykaal, but are not limited to these.

Next, specific examples of the polymer or copolymer used for the intermediate layer in the present invention are shown below, and in the description of those specific examples, n,
nl and n2Fi represent the average degree of polymerization.

n=180 n=70! 1=110 n=85! 1=140 n 1 =155 * n 2 =45n=155 n=175 nl"40 n 2 =35 nl == 120 nz == 60 n=65 n=145 n=60 n=170 nl ==110 n 2 ” 50 n=210 nl == 165, nz =:35n=140 n=175 n, =80, n2=80 n=205 In the present invention, the above-mentioned compound having a quaternary ammonium salt structure contained in the intermediate layer The polymer or copolymer is produced by, for example, synthesizing an acrylic acid thioester monomer or a methacrylic acid thioester monomer containing a quaternary ammonium salt from a glycityl thioester of acrylic acid or methacrylic acid and a hydrochloride of a trialkylamine, and then Polymerize this or copolymerize with this and other polymers.
It can be synthesized by copolymerizing with.

In the present invention, the intermediate layer can be composed of the above-mentioned polymers or copolymers alone, a mixture of two or more thereof, or a mixture of them and other resins or additives. Examples of other resins and additives include copolymerized nylon resin, N-methoxymethylated nylon resin,
Polyvinylpyrrolidone, polyacrylamide, polyvinyl butyral, polyglobylene glycol, surfactant.

There are also silicone leveling agents.

In the present invention, the thickness of the intermediate layer is 0.1 to 10.0μ.
It is particularly preferable that the coating has a thickness of 0.5 to 5.0μ, and is applied by dip coating, spray coating, roll coating, or other methods.

In the present invention, the photosensitive layer may be of a single layer type or may be of a laminated structure type in which a charge generation layer and a charge transport layer are separated in function.

The charge generation layer includes azo pigments such as Sudan Red and Guianplugenus Green B, Algol Yellow, Pyrenequinone, and Indanthrene Brilliant Violet R.
Quinone pigments such as RP, quinocyanine pigments, polyurethane pigments, indigo pigments such as indigo and thioindigo, bisbenzimidazole pigments such as India Fast Orange toner, 7-talocyanine pigments such as copper-7 talocyanine, and charge-generating substances such as quinacridone pigments. Dispersed in a binder resin such as polyvinyl butyral, polystyrene, polyvinyl chloride, polyvinyl acetate, acrylic resin, polyvinylpyrrolidone, methylcellulose, hydroxyglobil methylcellulose.

This dispersion can be formed by coating the above-mentioned intermediate layer. The thickness of such a charge generation layer is 5 microns or less, preferably 0.01 to 2 microns.

The charge transport layer provided on the charge generation layer contains a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, inoxazole, thiazole, imidazole, pyrazole, or oxadiazole in the main chain or side chain. It is formed using a coating solution in which a charge transporting substance such as a nitrogen-containing cyclic compound such as azole, pyrazoline, thiadiazole, or triazole, a hydrazone compound, or a styryl compound is dissolved in a resin that has film-forming properties. The reason why it is formed in this way is that the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself.

↓Polyester,
Examples include polysulfone, polycarzenate, polymethacrylates, polystyrene, and the like.

The thickness of the charge transport layer is 5 to 40μ, preferably 10 to 25μ
μ.

In addition to the above-mentioned photosensitive layer used in the present invention, poly-N
- An organic photoconductive polymer layer such as vinylcarbazole or polyvinylanthracene, a selenium evaporated layer, a selenium-tellurium evaporated layer or an amorphous silicon layer.

If the support used in the present invention has conductivity,
Any material may be used, such as aluminum, m, pa? −
/'7 Metals such as molybdenum, chromium, nickel, titanium, zinc, indium, and brass are formed into drums or sheets, and metal foils such as aluminum and copper are made of glass.

laminate on film, plastic film with aluminum, indium oxide, tin oxide, etc. deposited on it, metal or plastic film with a conductive layer formed by coating a conductive substance alone or with a suitable binder resin, An example is paper sudo.

The conductive substances used in this conductive layer include metal powders such as aluminum, copper, nickel, and silver; metal foils and short metal fibers; conductive metal oxides such as antimony oxide, tin oxide, and indium oxide; polypyrrole; Polymer conductive agents such as polyaniline polymer electrolyte; carbon fiber, car? Examples include electroconductive powder, graphite powder; organic and inorganic electrolytes; and conductive powder whose surface is coated with these conductive substances.

Further, as the binder resin of the conductive layer, polyvinyl alcohol, holly vinyl alkyl ether, holly N-t
'Nylimidazole, alkylcellulose, nitrocellulose, polyacrylic acid ester, casein, gelatin, polyester, polyamide, polyethylene oxide,
Polypropylene oxide, pre-amino acid ester, polyester vinyl.

Polycarnate, polyvinylpyrrolidone, chloroglene rubber, nitrile rubber, polymethacrylate ester, polypeptide, polymaleic anhydride, polyacrylamide, polyvinyl formal, polyvinylpyridine, polyethylene glycol, polypropylene glycol, polyvinyl butyral, chlorosulfonated polyethylene, Examples include thermoplastic resins such as thermoplastic polyurethane, thermosetting resins such as thermosetting polyurethane, phenol resins, and epoxy resins.

The mixing ratio of the conductive substance and the binder resin is 5:l~l:
It is about 5. This ratio is determined by considering the resistance, surface properties, coating suitability, etc. of the conductive layer.

If the conductive substance is a powder, use a ball mill, roll mill,
A mixture is prepared and used in a conventional manner using a sand mill, attritor, etc.

In addition, other additives include surfactants, silane coupling agents, titanate coupling agents, silicone oil,
A silicone leveling agent or the like may also be added.

Coating of the conductive layer is carried out by dip coating, spray coating, roll coating, etc., and the film thickness is approximately 0.5 to 30μ, taking into consideration the degree of defects and scratches on the support and the electrophotographic characteristics. It can be decided.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines but also for laser printers.
It can be used in printers, electrophotographic plate-making systems, etc.

The present invention will be explained in more detail with reference to specific examples below.

〔Example〕

Example 1 50 parts of titanium oxide powder coated with tin oxide containing 10% antimony oxide, 25 parts of resol type phenolic resin
1 part, 20 parts of methyl selon, 5 parts of methanol, and 0.002 parts of silicone oil (dimethylpolysiloxane polyoxyalkylene copolymer, average molecular weight: 3500) were dispersed for 1 hour in a sand mill using a raspize with 1φ diameter to conductivity. A layer paint was prepared.

The above paint was dip coated onto a 30φ aluminum cylinder and dried at 140°C for 30 minutes to form a conductive layer with a thickness of 20μ.

Next, 15 parts of the exemplary polymer A1 was dissolved in 85 parts of methanol to prepare an intermediate layer paint.

This solution was applied by dip coating onto the above conductive layer and heated to 100°C for 15 minutes.
It was dried for a minute to form an intermediate layer with a thickness of 1.5 μm.

10 parts of Nodrisazo pigment, polymethyl methacrylate (
After dispersing 5 parts (average molecular weight: 11,000) and 60 parts of cyclohexanone in a sand mill apparatus using 0.5φ glass beads for 5 hours, 120 parts of methyl ethyl ketone was added to prepare a dispersion. This dispersion was applied by dip coating onto the above intermediate layer and dried at 80°C for 20 minutes to obtain a 0.151
A charge generation layer with a coating weight of 7 m 2 was formed.

Next, 8 parts of the styryl compound having the structural formula and 0 parts of polycarbinate (average molecular weight: 8,000) were mixed with 40 parts of dichloromethane.
part and 20 parts of monochlorobenzene in a mixed solvent,
This solution is applied onto the charge generation layer by dip coating.

9. Dry at 120° C. for 50 minutes to form a charge transport layer with a thickness of 18 μm.

The electrophotographic photoreceptor manufactured in this way was attached to a radar printer LBP-SX manufactured by Canon Co., Ltd.
Under normal temperature and humidity (22℃, 55%RH) and high temperature and high humidity (3
When the electrophotographic characteristics of this photoreceptor were evaluated at a temperature of
t ), sufficient potential contrast can be obtained, and the dark potential (vci) ti can be maintained even under high temperature and high humidity.
Stable, good images with no black spots or capri are obtained.

The results are shown in Table 1.

Example 2 8 parts of the above-mentioned exemplary copolymer JP64 as an intermediate layer paint
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that a paint prepared by dissolving 1. The results are shown in Table 1.

Examples 3 to 6 As an intermediate layer paint, 10 parts each of the above-mentioned exemplary polymers or copolymers 3.11.14 and 19 were added to 9 parts of methanol.
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the paint dissolved in 0 parts was used, and evaluated in the same manner. The results are shown in Table IK.

Comparative Example 1 An electrophotographic photoreceptor was manufactured in the same manner as in Example 1, except that a paint for the intermediate layer in which 5 parts of the polymer having the structural formula was dissolved in a mixed solvent of 50 parts of methanol and 45 parts of water was used, Similar evaluations revealed that under high temperature and high humidity conditions, the dark area potential (Vd) decreased due to an increase in carrier flow from the support side, and capri was generated on one image. The results are shown in Table 1.

Table 1 did.

Next, 5 parts of the above exemplary polymer A9 having the structural formula was mixed with 90 parts of methanol and 5 parts of water.
A paint for the intermediate layer was prepared by dissolving KIW in a mixed solvent.

This paint for the intermediate layer was applied by dip coating onto a 30φ aluminum cylinder, which is a conductive support, and dried at 100°C for 20 minutes to form an intermediate layer with a film thickness of 0.5μ. Butyralization degree 69%, average molecular weight 19,000) 8 parts and cyclohexanone 60
5 parts with a sand mill machine using 0.5φ glass beads.
After time dispersion, 120 parts of Tetrahydro 7ran was added to prepare a dispersion.

A charge generating layer having a coating weight of 0.161//m 2 was formed by dip coating on the above intermediate layer.

Next, 10 parts of a hydrazone compound of the structural formula and styrene-methyl methacrylate copolymer (styrene/methyl methacrylate =
8/2, average molecular weight 35,000) 1 was dissolved in 80 parts of toluene. This solution was dip-coated onto the charge generation layer, and dried with hot air at 110°C for 1 hour.
A charge transport layer having a thickness of μ was formed.

The electrophotographic photoreceptor manufactured in this manner was attached to a copier FC-5 manufactured by Canon Co., Ltd. under normal temperature and humidity (21°C).
, 60% RH) and high temperature and high humidity (33°C, 85% RH)
), we evaluated the electrophotographic characteristics and found that the dark area potential did not fluctuate even under high temperature and high humidity conditions, and good images were obtained. The results are shown in Table 2.

Comparative Example 2 A structural formula was prepared as an intermediate layer paint and evaluated. Under high temperature and high humidity conditions, the dark area potential decreased due to increased carrier injection from the conductive support, resulting in a decrease in image density. The results are shown in Table 2.

Table 2 Example 8 Electrophotographic exposure was carried out in the same manner as in Example 7 except that 15 parts of a disazo pigment and polyvinyl butyral were used as a paint for the charge generation layer by dissolving 6 parts of the polymer having the structural formula in 94 parts of methanol. molecule 1iz
4. The same procedure as in Example 7 was carried out, except that a charge generation layer was formed using a paint prepared by adding 80 parts of methyl ethyl ketone after dispersing 5 parts of ooo) and 50 parts of cyclohexanone for 3 hours in a side mill device using lφ glass beads. middle l,
An electrophotographic photoreceptor provided with a charge transport layer was prepared.

The electrophotographic photoreceptor manufactured in this manner was attached to a Canon Co., Ltd. Hireday printer LBP-ST.
When 1,000 images were continuously produced at low temperature and low humidity (10° C., 10% RH), very stable images were obtained without any rise in bright area potential (Vt). The results are shown in Table 3.

Examples 9-10 10 parts of each of the above exemplary polymers 4 as an intermediate layer paint
Electrophotographic photoreceptors were prepared in the same manner as in Example 8, except that a paint containing Nos. 16 and 22 dissolved in methanol at 90 sK was used, and evaluated in the same manner. The results are shown in Table 3.

Comparative Example 3 An electrophotographic photoreceptor was prepared in the same manner as in Example 8, except that the special paint used in Comparative Example 1 was used as the intermediate layer paint, and evaluated in the same manner. As time progressed, the bright area potential (Vj) increased and the image density decreased. The results are shown in Table 3.

Table 3 [Effects of the Invention] The electrophotographic photoreceptor of the present invention contains a polymer or copolymer of hepacrylic acid thioester or methacrylic acid thioester having a quaternary ammonium salt structure shown in the claims in the intermediate layer. As a result, the barrier function deteriorates under high temperature and high humidity conditions.

There is almost no increase in resistance under low temperature and low humidity conditions, and the dark area potential decreases under high temperature and high humidity conditions, which was a problem with electrophotographic photoreceptors with conventional intermediate layers, and the bright area potential increases due to continuous use under low temperature and low humidity conditions. It has significantly improved environmental stability.

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor having a conductive support, a photosensitive layer, and an intermediate layer between them, the intermediate layer is a unit component ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula , R1 is a hydrogen atom or a methyl group, A is ▲ has a mathematical formula, chemical formula, table, etc. ▼ or ▲ has a mathematical formula, chemical formula, table, etc. ▼, and Z is an optionally substituted C1 to C6 alkylene group And Y■
▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In this case, R2, R3, and R4 are alkyl groups, phenyl groups, or benzyl groups, and these may be substituted, and B is a residue that forms a heterocycle with N. group, and D is N
= a residue that forms a heterocycle with C), and X■
is an anion.