JPS604457B2 - Photosensitive materials for electrophotography - Google Patents

Description

[Detailed description of the invention] The present invention relates to a light-sensitive material for electrophotography.

More specifically, the present invention aims to provide a light-sensitive material for electrophotography that has both film formation and photosensitivity. Conventionally known photoconductive substances used in electrophotographic photosensitive materials include inorganic substances such as selenium, zinc oxide, and cadmium sulfide, or anthracene, carbazole, anthraquinone, berylene, etc., or a series of polycyclic compounds,
and organic materials such as polyvinyl carbazole polymers and the like.

Xerox, electrophoax, etc. are known as those using inorganic substances. On the other hand, even if organic substances such as anthracene, carbazole, anthraquinone, and berylene are used, these are crystalline low-molecular compounds and do not form a film, and those using a series of heterocyclic compounds
It is characterized by the ability to obtain a transparent photosensitive layer and high sensitivity, but all of the substances are low-molecular compounds and do not have a film-forming mechanism of their own, so synthetic resin is used as a binder to make up 50% of the material.
In addition, they are used in solid solutions with photoconductive materials.
Furthermore, since photosensitive materials using polyvinyl carbazole are extremely brittle and have a weak film-forming ability, they still require a binder. A mixture of an electron-withdrawing substance and a resin obtained by co-condensing an aromatic condensed polycyclic compound consisting of 8 or more rings and/or its nuclear substituted product with an alkylbenzene aldehyde resin has these characteristics. It was discovered that
(See Publication No. 8).

However, the present inventors have discovered that when such a resin is nitrated with fuming nitric acid or the like, a resin can be obtained that provides the same level of photoconductivity without adding an expensive electron-withdrawing substance. Thus, according to the present invention, it has become possible to obtain a photoconductor that is inexpensive, easy to handle, and has good film-forming properties. That is,
The present invention provides a main photoconductor using a nitrated resin obtained by co-condensing an aromatic condensed polycyclic compound consisting of three or more rings and/or its nuclear substituted product with an alkylbenzene aldehyde resin. This is a photosensitive material for electrophotography. The alkylbenzene/aldehyde resin used in the present invention is a resin obtained by condensing an alkylbenzene and an aldehyde.

The alkylbenzene used to obtain the resin may be any benzene having 1 to 4 substituted alkyl groups, such as toluene, xylene, ethylbenzene, jetylbenzene, etc., but especially m -Dialkylbenzenes (eg m-xylene) are preferred.
As the aldehyde, an aliphatic aldehyde having 6 or less carbon atoms (typical examples include formaldehyde, acetaldehyde, furfural, etc.) is preferably used, and formaldehyde is particularly preferably used. Therefore, the most preferred resin is m-xicine formaldehyde resin. The aromatic integrated polycyclic compound used in the present invention has a condensed ring consisting of three or more rings. Basic examples of such compounds (those having no nuclear substituents) include anthracene, phenanthracene, pennzanthracene, birene, chrysene, tetraphenone, tetracene, berylene, 1,215,6-dibenzanthracene, etc. These include 1 to 1 inert substituents such as lower alkyl groups.
You may have three. The aromatic condensed polycyclic compound may be used alone or in combination of two or more. The blending ratio of the alkylbenzene aldehyde resin and the aromatic condensed polycyclic compound should be adjusted to ensure appropriate sensitivity and excellent film formation, as too little of the latter tends to reduce the sensitivity of the resin, while too much of the latter tends to make the resin brittle. In order to achieve both, the weight ratio of the latter to the former is usually 0.2 to 1. The ratio of Mushi Samurai is preferably 0.4 to 1.0. However, depending on the purpose, it may be blended in a ratio outside this range. The alkylbenzene aldehyde resin used is one that can still be melted, and is subjected to a co-condensation reaction with the aromatic condensed polycyclic compound.

The reaction temperature is preferably 100 to 300 CO, and the reaction time is preferably 10 minutes to 10 hours. The reaction is preferably carried out under an inert gas atmosphere or under reduced pressure. The resinous material thus obtained is nitrated by a conventional method.

That is, methods using fuming nitric acid, a mixed acid of nitric acid and sulfuric acid, etc. can be mentioned. The degree of nitration can be determined through experiments to ensure optimum photoconductivity depending on the intended use. Generally, those having a nitrogen content of about 0.3 to 6% are used. The photosensitive cocondensate thus obtained has both film-forming ability and photosensitivity (photoconductivity), and can be used as a photosensitive material for electrophotography as it is, or with a sensitizer and a plasticizer as necessary. A solution is formed by adding an agent, etc., and the solution is coated on a support and dried.

A dye is preferably used as the sensitizer. By adding a dye, the photosensitive region of the photosensitive resin moves to the light absorption region of the dye, that is, the visible region, and the resin exhibits sufficient sensitivity even in the visible region. Examples of such dyes include brilliant, green, methyl violet, crystal violet, rhodamine B, rhodamine B extract, rhodamine 83, sulfurhodamine B, rose bengal, methylene blue, and alizarin. A preferable addition ratio of the sensitizer to the photosensitive resin is 0.01 to 3. % by weight, but it is not necessarily necessary to add it. Examples of the plasticizer include p-terphenyl, diphenyl, diphenyl ether, diphenyl chloride, methylnaphthalene, dioctyl phthalate triphenyl phosphate, dimethyl glycol phthalate, dibutyl phthalate, and the like.

The addition of plasticizers improves the properties of the coating. The addition ratio of the plasticizer is preferably 1 to 4% by weight based on the photosensitive resin, but it is not necessarily necessary to add the plasticizer. A known method may be used to apply the solution containing the photosensitive material to the support.

For example, methods such as casting the solution, spin coating, spraying, brush coating, etc. may be used. The thickness of the film is usually 2~
30 Buddhas is preferred. The support may be any material as long as it can be used as a support for the photosensitive layer for electrophotography; for example, a metal plate made of aluminum, zinc, copper, etc., or a surface treated with synthetic resin to prevent solvent from penetrating inside. Materials with a surface resistivity lower than that of the photoconductive layer, such as synthetic resin films mixed with or coated with antistatic agents or surfactants to lower the electrical resistivity, that is, usually 1 pi○・
Anything less than 100%, preferably 100mm or less is acceptable. Any conventionally known method may be used as the operating method for obtaining an electrophotographic image, and the charging potential may be either positive or negative.

The electrophotographic light-sensitive material of the present invention has excellent sensitivity and excellent film-forming ability.

Therefore, a photosensitive sheet made by coating this on a transparent film is
It is used for masters and duplicates of slides, micro-photographs, overhead projectors, etc., and when coated and baked on a metal cylinder, it is used as a transfer tube for xerography. Furthermore, the paper coated with it is more similar to plain vapor than conventional zinc oxide coated paper, and it is possible to obtain copies that are similar to plain vapor copies without using a transfer process. Hereinafter, the present invention will be explained in detail with reference to Examples.

Comparative example 1 Xylene formaldehyde resin (trade name Nicanol S
Using IO0 (Mitsubishi Gas Chemical KK product)) 9.6 pieces, add 5.5 hours of anthracene, and boil under nitrogen stream for 160 ~
The reaction was carried out at a temperature of 19,000 ℃ for 4 hours, and the reactant was dissolved in toluene and resoaked using methanol to obtain condensate A.

The condensate was dissolved in m-cresol, cast, coated and dried on an aluminum plate to form a photoconductive layer with a thickness of 10 μm.

This layer was negatively charged by corona discharge. This was placed under the original and exposed for 5 seconds from a distance of 20 degrees using a 300W incandescent light bulb as a light source, then sprinkled with developing powder and heated to fix it, resulting in an image faithful to the original. In addition, Surf S, potentiometer SSO-300I (formerly KK product) and photovoltaic illumination meter SPI-1 (Toshiba Electric K.K.
When we measured the half-decreased exposure using K product), it was 1.4
×1pi Lux. It was sec.

Example 1 The condensate A obtained in Comparative Example 1 was added with fuming nitric acid (N02 content 12.7%, d≧o=1.526) and 3 at room temperature.
When reacted for a time, the nitrogen content was 0. A condensate B was obtained in which nitro groups were introduced in an amount corresponding to the mother weight %.

The condensate was coated on an aluminum plate in the same manner as in Example 1, and this layer was negatively charged.

When this was placed under the original and exposed for 2 seconds and developed, an image faithful to the original was obtained. The half-decreased exposure amount measured under the same conditions as Comparative Example 1 was 120 peaks ux. It was sec. Comparative Example 2 Xylene-formaldehyde resin and anthracene were simply mixed in the same proportions as in Comparative Example 1, without co-condensation, and dissolved in m-cresol, and the resulting solution was used in the same manner as in Example 1 to prepare aluminum. I applied it on a board to form a coating and tried to copy it, but no image could be obtained.

Comparative Example 3 Polyvinylcarbazole was purified by pulverizing it, dissolving it in methylene chloride, and reprecipitating it using purified methanol three times.

The purified polyvinyl carbazole is treated with chlorobenzene (
Example 1
It was applied to an aluminum plate in the same manner as above to form a film. When the half-decreased exposure amount of this product was measured in the same manner as in Example 1, it was found to be 1.6×1 piL. It was sec. The resulting film had many cracks and was easily peeled off.

Claims (1)

[Claims] 1 Aromatic fused polycyclic compound consisting of 3 or more rings and/
or a photosensitive material for electrophotography whose main photoconductor is a nitrated resin obtained by co-condensing a nuclear substituted product thereof with an alkylbenzene aldehyde resin.