JPH0311360A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent the degradation in a barrier function at and under a high temp. and high humidity and the degradation in dark part potential by providing an intermediate layer contg. polyol compds. different in weight average mol. wt. CONSTITUTION:The intermediate layer 2 contains the polymer of an isocyanate compd. and the polyether polyol compds. consisting of the plural components different in the weight average mol. wt. The photosensitive layer may be a laminated structure type separated in function to a charge generating layer 3 and a charge transfer layer 4 or may be a single layer 5 contg. the charge generating material and the charge transfer material in the same layer. The polyol compds. contain the polyol components of the different weight average mol. wt. at the time of forming polyurethane, by which the increase in resistance at and under a low temp. and low humidity is suppressed as compared to the case of using the single polyol compd. The formation of the smooth coating film on a substrate is thus possible. The degradation in the dark part potential at and under the high temp. and high humidity is lessened and the photosensitive body having a sufficient barrier function as the intermediate layer is obtd.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, an electrophotographic photoreceptor in which an intermediate layer having functions as an adhesive layer and a barrier layer is provided on a conductive support. Regarding the body.

[Conventional technology]

Generally, Carlson type electrophotographic photoreceptors are charged with
In order to form images with constant image density and no background smearing when exposure is repeated, the stability of the dark area potential and the bright area potential is important.

For this reason, it functions as a barrier layer between the photosensitive layer and the conductive support, and provides adhesion between the photosensitive layer and the conductive support, in order to protect the surface of the support from defects, dirt, deposits, scratches, etc. It has been proposed to provide an intermediate layer that functions as a layer.

Such an intermediate layer is made of polyamide (Japanese Patent Application Laid-open No.
47344, JP-A-52-25638), polyester (described in JP-A-52-20836, JP-A-54-26738), polyurethane (JP-A-49-10044, JP-A-52-26738) Showa 53-89435
Casein (described in JP-A-55-103556), polypeptide (described in JP-A-53-48523), polyvinyl alcohol (described in JP-A-52-10)
0240), polyvinylpyrrolidone (described in JP-A-48-30936), vinyl acetate-ethylene copolymer (described in JP-A-48-26141), maleic anhydride ester polymer (described in JP-A-48-26141), -10138), polyvinyl butyral (Japanese Unexamined Patent Publication No. 57-90
No. 639, JP-A-58-106549)
, quaternary ammonium salt-containing polymer (JP-A-51-126
No. 149, JP-A No. 56-60448),
It is known to use resins such as ethyl cellulose (described in JP-A-55-143564).

However, in 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 deteriorates under high temperature and humidity, and the dark area potential decreases due to carrier injection from the support side, making it difficult to copy. There was a drawback that the density of the image was reduced.

Further, when such a photoreceptor is used in an electrophotographic printer that performs reversal development, there is a problem in that images are fogged under high temperature and high humidity conditions.

In particular, in a laminated electrophotographic photoreceptor in which the photosensitive layer has a charge generation layer and a charge transport layer laminated in sequence, the charge generation layer containing a high concentration of a charge generation substance is located in contact with the intermediate layer, so carriers from the support side A drop in potential due to increased injection is more likely to occur, and even if the barrier function of the intermediate layer is slightly reduced, fog is likely to occur in printers using a reversal development system.

Furthermore, when photoreceptors using conventional materials for the intermediate layer are used repeatedly, the potential in the bright area tends to increase and the potential in the dark area tends to fluctuate. 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.

[Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor that can obtain a stable dark potential against changes in temperature and humidity environment.

Another object of the present invention is to provide an electrophotographic photoreceptor that suppresses increases in bright area potential and fluctuations in dark area potential even after repeated use.

[Means for solving problems]

That is, the present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support via an intermediate layer, in which the intermediate layer is made of a polymer of a polyether polyol compound comprising an incyanate compound and a plurality of components having different weight average molecular weights. An electrophotographic photoreceptor characterized by containing:

In the present invention, when producing polyurethane, which is a polymer of a polyol compound and an isocyanate compound, this polyol compound contains polyol components having different weight average molecular weights that meet the above conditions, which makes it easier to produce polyurethane than when using a single polyol compound. In particular, the increase in resistance at low temperatures and low humidity is suppressed, and a smooth coating film can be formed on the support. In addition, the decrease in dark potential under high temperature and high humidity is small (and the barrier function as an intermediate layer is also sufficient).In particular, the ratio between the smallest weight average molecular weight and the largest weight average molecular weight of polyether polyol compounds can be obtained. is preferably 1.3 or more in terms of potential stability.

Next, specific examples of materials contained in the intermediate layer used in the present invention are shown below.

Polyether polyol compounds used as raw materials for the intermediate layer of the present invention include poly(oxypropylene) glycol, poly(oxypropylene) poly(oxyethylene) glycol, poly(oxybutylene) glycol, poly(oxytetramethylene) Poly(oxyalkylene) glycols such as glycol, poly(oxyalkylene) triols such as poly(oxypropyne) triol, poly(oxypropyne) poly(oxyethylene) triol, poly(oxybutyl) triol, ethylene diamine, penta Poly(oxypropylene) polyols, poly(oxypropylene) using erythritol, sorbitol, sucrose, starch, etc. as initiators
Examples include poly(oxyalkylene) polyols such as poly(oxyethylene) polyol.

Isocyanate compounds used as raw materials for the intermediate layer include aromatic isocyanate compounds such as tolylene diisocyanate, metaxylylene diisocyanate, diphenylmethane diisocyanate, and polymethylene polyphenylisocyanate, water additives of the above incyanates, hexamethylene diisocyanate, etc. aliphatic isocyanate compounds, and blocked isocyanate compounds in which the isocyanate group of these isocyanate compounds is blocked with phenol, ketoxime, aromatic secondary amine, tertiary alcohol, amide, lactam, heterocyclic compound, sulfite, etc. Can be mentioned.

In addition, as catalysts that promote the formation of polymers, naphthenic acid salts such as magnesium naphthenate and cobalt naphthenate, tin compounds such as dibutyltin dilaurate and dimethyltin dilaurate, N-methylmorpholine, N, N,
An amine compound such as N',N'-tetramethylpolymethylenediamine may also be added. The amount of catalyst added is 0.05 to 5% by weight based on the polymer.

The appropriate molar ratio of isocyanate groups (NCO groups) and hydroxyl groups (OH groups) in the polymer raw material is 1.0≦NCO groups 1
It is desirable that 0H group≦2.0. If the molar ratio is lower than 1.0, the sensitivity of the photoreceptor deteriorates and the barrier properties of the intermediate layer tend to deteriorate under high temperature and high humidity conditions. On the other hand, if the molar ratio is larger than this, the adhesion of the coating film tends to decrease.

Further, among the polyol components contained in the intermediate layer, the proportion of each component having a weight average molecular weight ratio of 1.5 or more is preferably small (both are preferably 20% or more).

The intermediate layer in the present invention has a thickness of 0.1 to 10.0 μm
1, particularly preferably 0.5 to 5.0 μm, and is applied by dip coating, spray coating, roll coating, or other methods.

The layer structure of the electrophotographic photoreceptor of the present invention is shown in FIG. 1''.

In the present invention, the photosensitive layer may be of a laminated structure type in which the charge generation layer 3 and the charge transport layer 4 are functionally separated, or may be a single layer 5 containing a charge generation substance and a charge transport substance in the same layer.

The charge generation layer 3 is made of azo pigments such as Sudan Red and Guianprugienas Green B, quinone pigments such as Algol Yellow, Pyrenequinone, and Indanthrene Brilliant Violet RRP, indigo pigments such as quinocyanine pigments, perylene pigments, indigo and thioindigo, and indigo pigments such as Indigo and Thioindigo. Charge generating substances such as bisbenzimidazole pigments such as Fast Orange toner, phthalocyanine pigments such as copper phthalocyanine, and quinacridone pigments are combined with polyvinyl butyral, polystyrene, polyvinyl chloride, polyvinyl acetate, acrylic resin, polyvinylpyrrolidone, methyl cellulose, hydroxypropyl methyl cellulose, etc. It can be formed by dispersing it in a binder resin and coating this dispersion on the undercoat layer 2 of the present invention. The thickness of such a charge generation layer is 0.5 μm or less, preferably 0.0 μm or less.
A suitable thickness is 1 μm to 2 μm.

The charge transport layer 4 provided on the charge generation layer 3 has a main chain or a side chain containing a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, inoxazole, thiazole,
It is formed using a coating liquid in which charge transport substances such as nitrogen-containing cyclic compounds such as imidazole, pyrazole, oxadiazole, pyrazoline, thiadiazole, and triazole, hydrazone compounds, and styryl compounds are dissolved in a resin that has film-forming properties. Ru. This is because the charge transport material generally has a low molecular weight and has poor film-forming properties by itself.

Such resins include polyester, polysulfone,
Examples include polycarbonate, polymethacrylates, polystyrene, and the like.

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

Further, the charge generation layer 3 may be laminated on the charge transport layer 4.

Furthermore, in addition to the above-mentioned photosensitive layers used in the present invention, examples include organic photoconductive polymer layers such as poly-N-vinylcarbazole and polyvinylanthracene, selenium vapor deposition layers, selenium-tellurium vapor deposition layers, and amorphous silicon layers. .

The conductive support used in the present invention may be any material as long as it has conductivity (for example, aluminum, copper,
Metals such as molybdenum, chromium, nickel, and brass molded into drum or sheet shapes, metal foils such as aluminum and copper laminated onto plastic films, and aluminum, indium oxide, tin oxide, etc. deposited on plastic films. or the metal or plastic film having a conductive layer coated with a conductive substance alone or together with a suitable binder resin;
Examples include paper.

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, Examples include polymer conductive agents such as polyaniline and polymer electrolytes, carbon fiber, carbon black, graphite powder, organic and inorganic electrolytes, and conductive powders whose surfaces are coated with these conductive substances.

Binder resins for the conductive layer include polyvinyl alcohol, polyvinyl alkyl ether, poly-N-vinylimidazole, alkyl cellulose, nitrocellulose, polyacrylic ester, casein, gelatin, polyester, polyamide, polyethylene oxide, polypropylene oxide, and polyamino acid. Ester, polyvinyl acetate, polycarbonate, polyvinylpyrrolidone, chloroprene rubber, nitrile rubber, polymethacrylic ester, polypeptide, polymaleic anhydride, polyacrylamide, polyvinyl formal, polyvinylpyridine, polyethylene glycol, polypropylene glycol, polyvinyl butyral, chloro Examples include thermoplastic resins such as sulfonated polyethylene and thermoplastic polyurethane, thermosetting resins such as thermosetting polyurethane, phenol resin, and epoxy resin.

The mixing ratio of the conductive substance and the binder resin is 5:1 to 1:5.
That's about it. This ratio is determined by considering the resistance, surface properties, suitability of coating, etc. of the conductive layer.

When the conductive substance is a powder, a mixture is prepared and used in a conventional manner using a ball mill, roll mill, sand mill, attritor, or the like.

Further, other additives such as a surfactant, a silane coupling agent, a titanate coupling agent, a silicone oil, and a silicone leveling agent may be added.

The conductive layer is applied by dip coating, spray coating, roll coating, etc., and the film thickness is approximately 0.5 μm to 30 μm, which is determined by taking into account the degree of defects and scratches on the support and the electrophotographic characteristics. It will be done.

Furthermore, the electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in laser printers, CRT printers, electrophotographic plate making systems, and the like.

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

Example 1 and Comparative Example 1 50 parts by weight of titanium oxide powder coated with tin oxide containing 10% antimony oxide (hereinafter referred to as parts), 25 parts of resol type phenolic resin, 20 parts of methyl cellosolve, 5 parts of methanol, silicone Oil (dimethylpolysiloxane polyoxyalkylene copolymer average molecular weight: 35
00) was dispersed for 1 hour using a sand mill device using 1φ glass beads to prepare a coating material for a conductive layer.

The above paint was applied by dip coating onto an aluminum cylinder of 60 mmφ x 260 mm and dried at 140° C. for 30 minutes to form a conductive layer with a thickness of 20 μm.

Next, poly(oxypropyl)triol (hydroxyl value 14
8.9mgKOH/g, weight average molecular weight 1130)2.
8 parts, poly(oxypropylene) triol (hydroxyl value 114.5 mgKOH/g, weight average molecular weight 1470)
2.8 parts of dibutyltin dilaurate, 0.02 parts of dibutyltin dilaurate dissolved in 80 parts of methyl ethyl ketone (weight average molecular weight ratio: 1.3), and poly(oxypropylene) triol (hydroxyl value 114.5 mgKOH/g, weight average molecular weight 1470) ) 6.2 parts, dibutyltin dilaurate 0.
A solution prepared by dissolving only 2 parts of 0.02 parts in 80 parts of methyl ethyl ketone was prepared. A ketoxime block of hexamethylene diisocyanate (effective NCO: 1
A paint for the intermediate layer was prepared by adding 5.5 parts of 1,6 type O:) so that the molar ratio of NCO groups and 10H groups was 1.2.

These respective solutions were dip coated onto the conductive layer, and 18
It was dried and cured at 0° C. for 40 minutes to form an intermediate layer with a thickness of 1.2 μm.

Next, 10 parts of trisazo pigment of the following structural formula, polymethyl methacrylate (
After dispersing 5 parts (number average molecule -ffi: 11000) 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 dip coated onto the above intermediate layer, dried at 80°C for 20 minutes, and
．． A charge generation layer was formed with a coating weight of 15 g/rd.

Next, 10 parts of a stilbene compound having the following structural formula and 10 parts of polycarbonate (weight average molecular weight: 8000) were mixed with 4 parts of dichloromethane.
0 parts of monochlorobenzene and 20 parts of monochlorobenzene, and this solution was applied by dip coating onto the charge generation layer, and heated at 120°C.
This was dried for 60 minutes to form a charge transport layer with a thickness of 20 μm.

The photoconductor produced in this way was attached to a laser beam printer (manufactured by LBP-CX Canon), and
The electrophotographic properties were evaluated at C190%RH).

As a result, as shown in Table 1, both showed good sensitivity, the difference between the dark area potential (L+) and the bright area potential (Vz) was large, and sufficient potential contrast was obtained. Under high temperature and high humidity conditions, the photoreceptor having an intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.3 had a stable dark area potential (Vd) and good images without black spots or fog were obtained. A photoreceptor having an intermediate layer containing only a single polyol component showed image defects due to coating defects.

On the other hand, under low temperature and low humidity (・15℃, 10%RH)
When images were printed on 00 sheets, very stable images were obtained with the photoreceptor having an intermediate layer containing the mixed polyol compound without any increase in bright area potential (Vz). On the other hand, in the photoreceptor having an intermediate layer containing only a single polyol compound, the bright area potential (Vl) increased significantly and the image density decreased.

Further, while the intermediate layer containing only a single polyol compound showed some repellency in appearance, the intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.3 provided a smooth coating film.

Example 2 and Comparative Example 2 As a paint for the intermediate layer, 1.1 parts of poly(oxypropylene) glycol (hydroxyl value 267.1 mgKOH/g, weight average molecular weight 420), poly(oxypropylene) glycol (hydroxyl value 133, 6 m gKOH/
g, weight average molecular weight 840), 0.02 parts dibutyltin dilaurate dissolved in 80 parts methyl ethyl ketone (weight average molecular weight ratio: 2.0), poly(
oxypropylene) gelcol (hydroxyl value 267.1m
gKOH/g.

A ketoxime block of hexamethylene diisocyanate (effective NCO: 11.6% by weight) was added to a solution of 2.0 parts (weight average molecular weight: 420) and 0.02 parts of dibutyltin dilaurate in 80 parts of methyl ethyl ketone (effective NCO: 11.6% by weight). of paint (NCO group 10H)
A photoreceptor was produced in the same manner as in Example 1, except that the base molar ratio: 1.5) was used, and it was evaluated in the same manner.

As a result, as shown in Table 1, stable characteristics were obtained under both normal temperature and humidity conditions and high temperature and high humidity conditions, but under low temperature and low humidity conditions, the photoreceptor with an intermediate layer containing only a single polyol compound was bright. A significant increase in partial potential (Vz) and a decrease in image density were observed.

Moreover, the appearance of the intermediate layer containing only a single polyol compound is somewhat nonuniform, whereas the weight average molecular weight ratio of 2.0
A smooth coating film was obtained for the intermediate layer containing the polyol compound.

Example 3 and Comparative Example 3 Poly(oxypropylene) polyol (hydroxyl value 11) using pentaerythritol as an initiator as an intermediate layer coating.
8.1mgKOH/g, weight average molecular weight 1900) 4
．． Poly(oxypropylene) using the same initiator as 8 parts
Polyol (hydroxyl value 7s, 7mgKOH/g.

9.6 parts (weight average molecular weight: 2850), 0.3 parts of triethylenediamine dissolved in 100 parts of isobutyl acetate (weight average molecular weight ratio: 1.5), and poly(oxypropylene) polyol using pentaerythritol as an initiator. (Hydroxyl value 196, 8 mg KOH/g
, weight average molecule ffi 1140) 6.5 parts and 0.3 parts of triethylenediamine dissolved in 100 parts of isobutyl acetate, and 3.0 parts of metaxylylene diisocyanate were added to each of the dissolved paints (NCO group 10H group mol). A photoreceptor was prepared in the same manner as in Example 1, except that a photoreceptor (ratio: 1.4) was used, and evaluated in the same manner.

As a result, as shown in Table 1, stable characteristics were obtained under normal temperature and normal humidity conditions, but under high temperature and high humidity conditions, a photoreceptor with an intermediate layer containing only a single polyol compound showed Image defects were observed.Furthermore, under low temperature and low humidity conditions, the photoreceptor having an intermediate layer containing only a single polyol compound showed a significant increase in bright area potential (Vz) and a decrease in image density.

Also. The intermediate layer containing only a single polyol compound has a highly repellent appearance (and extremely poor coatability).

On the other hand, a smooth coating film was obtained in the intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.5.

Example 4 and Comparative Example 4 As a paint for the intermediate layer, 1.8 parts of poly(oxypropylene) triol (hydroxyl value 374 mg KOH/g weight average molecular weight 450) and poly(oxypropylene) triol (hydroxyl value 233, 8 m g K OH/
g, weight average molecular weight 720), 0.02 parts of dibutyltin dilaurate and 80 parts of methyl ethyl ketone.
(weight average molecular weight ratio: 1.6) and poly(oxypropylene) triol (hydroxyl value 374 m
gKOH/g.

weight average molecular weight 450) 1.5 parts, poly(oxypropylene) triol (hydroxyl value 311.7 mgKOH/
g.

To a solution of 1.5 parts of hexamethylene diisocyanate (weight average molecular weight 540) and 0.02 parts of dibutyltin dilaurete dissolved in 80 parts of methyl ethyl ketone (weight average molecular weight ratio: 1.2), a ketoxime block form of hexamethylene diisocyanate ( A photoreceptor was prepared in the same manner as in Example 1, except that a paint (NCO group 10H group molar ratio: 1.5) in which 10 parts of effective NCO (effective NCO: 11.6% by weight) was added and dissolved was used, and evaluated in the same manner. did.

As a result, as shown in Table 1, stable characteristics were obtained under both normal temperature and humidity conditions and high temperature and high humidity conditions, but under low temperature and low humidity conditions, the photoreceptor having an intermediate layer with a weight average molecular weight ratio of 1.2 There was a significant increase in bright area potential and a decrease in image density.

Moreover, the intermediate layer with a weight average molecular weight ratio of 1.2 has an uneven appearance, whereas the intermediate layer with a weight average molecular weight of 1.6 has a smooth coating film.

Example 5 and Comparative Example 5 Poly(oxypropylene) triol (hydroxyl value 70.
1mgKOH/g, weight average molecule, 112400)6.
1 part, poly(oxypropylene) triol (hydroxyl value 39, Omg K OH/g, weight average molecular weight 4320) 9.1 parts, triethylenediamine 0.15 parts dissolved in 100 parts methyl ethyl ketone (weight average molecular weight ratio : 1.8) and poly(oxypropylene)
Triol (hydroxyl value 46.8 mgKOH/g weight average molecular weight 3600) 6.9 parts, poly(oxypropylene)
Triol (hydroxyl value 39, 0 mg KOH/
g, weight average molecular weight 4320), 10.3 parts of triethylenediamine and 100 parts of methyl ethyl ketone.
(weight average molecular ratio: 1.2) was prepared. An intermediate layer coating material was prepared by adding 2.0 parts of tolylene diisocyanate to each of these solutions so that the molar ratio of NCO groups and 10H groups was 1.8.

Each of the above intermediate layer paints was applied by dip coating onto an aluminum cylinder of 30 mφ x 260 mm as a conductive support, and dried at 120° C. for 60 minutes to form an intermediate layer having a thickness of 0.8 μm.

Next, 10 parts of a disazo pigment with the following structural formula was added to polyvinyl butyral resin (
Butyralization degree 70%, number average molecular weight 24,000)6
1 part and 60 parts of cyclohexanone were dispersed for 5 hours in a sand mill apparatus using lφ glass beads. 100 parts of methyl ethyl ketone was added to this dispersion, and the mixture was dip-coated onto the intermediate layer, and dried by heating at 100°C for 10 minutes.
A charge generation layer was formed with a coating weight of 5 g/rrr.

Next, 10 parts of a hydrazone compound having the following structural formula and a styrene-methyl methacrylate copolymer (styrene/methyl methacrylate = 8
72. average molecular weight 35,000) 15 parts to 8 parts toluene
Dissolved in 0 parts. This liquid was dip-coated onto the charge generation layer and dried with hot air at 100° C. for 1 hour to form a charge transport layer with a thickness of 18 μm.

The photoconductor produced in this way was used in a small copying machine (Fe2,
(manufactured by Canon) and at room temperature (23℃, 55%
The electrophotographic properties were evaluated under high temperature and high humidity conditions (33° C., 190% RH).

As a result, as shown in Table 1, both showed good sensitivity;
The difference between the dark area potential (Vd) and the light area potential (Vl) was large, and sufficient potential contrast was obtained, and the dark area potential did not fluctuate under high temperature and high humidity conditions, and a good image was obtained.

On the other hand, under low temperature and low humidity (15℃, 10%RH)
When 0 images were produced, the photoreceptor having an intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.8 showed no increase in bright area potential (Vz) (a very stable image was obtained). On the other hand, a photoreceptor having an intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.2 has a bright area potential (Vz
) increased significantly, causing fog. Furthermore, a coating film with a uniform appearance was obtained for the intermediate layer.

Example 6 and Comparative Example 6 Poly(oxypropylene) glycol (hydroxyl value 92, Omg KOH/g,
Weight average molecular weight 1220) 1.7 parts, poly(oxypropylene) glycol (hydroxyl value 54, 2 mg K
OH/g, weight average molecular weight 2070), 7.0 parts dibutyltin dilaurate dissolved in 100 parts methyl ethyl ketone (weight average molecular weight ratio: 1
．． 7) and poly(oxypropylene) glycol (hydroxyl value 92.0 mgKOH/g.

weight average molecular weight 1220) 2.2 parts, poly(oxypropylene) glycol (hydroxyl value 83.7 mgKOH/
g.

1.0 part of hexamethylene diisocyanate was added and dissolved in 100 parts of methyl ethyl ketone (weight average molecular weight ratio: 1.1) containing 8.8 parts of mold mouth average molecular weight fil1340) and 0.05 part of dibutyltin dilaurate (weight average molecular weight ratio: 1.1). Paint (NCO group 10H group molar ratio: 1.3)
A photoreceptor was produced in the same manner as in Example 5, except that the photoreceptor was used, and evaluated in the same manner.

As a result, as shown in Table 1, stable characteristics were obtained both at room temperature and humidity, and at high temperature and high humidity. The body has a large rise in light potential (Vz),
Fog occurred.

Further, the appearance of the intermediate layer containing a polyol compound having a weight average molecular weight ratio of 1.1 was a non-uniform coating film.

On the other hand, the intermediate layer containing a polyol compound having a weight average molecular weight ratio of 1.7 provided a smooth coating film.

Example 7 and Comparative Example 7 Poly(
oxypropylene) polyol (hydroxyl value 623, 3
mg KOH/g, weight average molecular weight 360)
Poly(oxypropylene) using the same initiator as part 2
Polyol (hydroxyl value 284.1 mgKOH/g, weight average molecular weight 790) 4 parts, dibutyltin dilaurate 0
．． 02 parts dissolved in 100 parts of methyl ethyl ketone (weight average molecular weight ratio: 2.2) and poly(oxypropylene) polyol using sorbitol as an initiator (hydroxyl value 623, 3 mg K OH/g, weight average molecular weight 360) 1.9 parts and poly(oxypropylene) polyol (hydroxyl value 561.0) using the same initiator.
mg K OH/g 1 weight average molecular weight 400)
A coating material (NCO group 10 )
A photoreceptor was prepared in the same manner as in Example 5 except that (base molar ratio: 1.6) was used, and it was evaluated in the same manner.

As a result, as shown in Table 1, stable characteristics were obtained under normal temperature and normal humidity conditions, but under high temperature and high humidity conditions, the photoreceptor having an intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.1 Image defects were observed.

Under low temperature and low humidity conditions, a photoreceptor having an intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.1 has a bright area potential (Vl).
The increase was large, causing fog.

In addition, the appearance of the intermediate layer containing a polyol compound with a weight average molecular weight ratio of 1.1 has a lot of repellency, whereas the intermediate layer containing a polyol compound with a weight average molecular weight ratio of 2.2 provides a smooth coating film. It is being

(The following are blank spaces) +', 1- -" [Effects of the Invention] As described above, according to the electrophotographic photoreceptor of the present invention, there is almost no decrease in barrier function under high temperature and high humidity conditions, and almost no increase in resistance under low temperature and low humidity conditions. (The problems of conventional electrophotographic photoreceptors with an intermediate layer, such as the decrease in dark area potential under high temperature and high humidity conditions and the increase in light area potential due to continuous use under low temperature and low humidity conditions, have been significantly improved, resulting in excellent environmental stability. You can get sex.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the layer structure of an electrophotographic photoreceptor. 603- (CA) (shi)

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor having a photosensitive layer on a conductive support via an intermediate layer, the intermediate layer contains a polymer of an isocyanate compound and a polyether polyol compound consisting of multiple components having different weight average molecular weights. An electrophotographic photoreceptor featuring: (2) The electrophotographic photoreceptor according to claim 1, wherein the ratio of the smallest weight average molecular weight to the largest weight average molecular weight of the polyether polyol compound is 1.3 or more.