JPS5921019B2 - electrophotographic plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic plate using a photosensitive layer made of copper phthalocyanine having an ε (epsilon) crystal form.

More specifically, the present invention relates to an electrophotographic plate having excellent sensitivity, repeatability, printing durability, etc. Currently widely used photoconductive layer elements for electrophotographic plates include:
Examples include amorphous selenium, cadmium sulfide, zinc oxide, and polyvinyl carbazole.

Amorphous selenium has good properties as a photoconductive layer element, but it is difficult to manufacture because it must be manufactured by vapor deposition, and the vapor-deposited film is not flexible and is extremely toxic, so be careful when handling it. The drawback is that it requires a lot of work and is expensive. Cadmium sulfide and zinc oxide are used in the form of a photosensitive layer dispersed in a binder resin, but practical sensitivity cannot be obtained unless the resin/photoconductive layer element weight ratio is less than 0.2 to 0.3. Therefore, it has disadvantages in mechanical properties such as flexibility, smoothness, hardness, tensile strength, and abrasion resistance. Therefore, it cannot withstand repeated use as it is. Further, practical sensitivity cannot be obtained unless additives such as sensitizers are used. The toxicity of cadmium sulfide also needs to be considered.
On the other hand, although organic photoconductor elements such as polyvinicarbazole have advantages such as charge retention, transparency, and self-forming properties of specific gravity polymer photosensitive materials, their photosensitivity is significantly lower than that of inorganic photosensitive materials. Therefore, it cannot be put to practical use unless a sensitizer with superior sensitivity is developed. Although such conventional photoelectric elements are currently in use, they also have various drawbacks.

In 948, Eley et al.
The electrical properties of anine compounds were measured, and it was revealed that metal-free phthalocyanine and metal phthalocyanine are intrinsic semiconductors.
Since the discovery of the photoconductivity of phthalocyanine by Dr. SeikO), there have been various changes in phthalocyanine, depending on its central metal and crystalline type.
There are many research reports on the effects on electrical characteristics, etc.

Phthalocyanine compounds are crystalline semiconductors, and their crystal forms vary depending on the manufacturing conditions, and their properties are sensitively reflected by the composition of the components resulting from the differences in the crystalline states and the raw materials used for manufacturing. . Copper phthalocyanine is a substance that is widely used as an organic pigment, and depending on its manufacturing conditions, it can be produced in α, β. 、． δ． It is known that crystal forms such as , π type, etc. exist. Japanese Patent Publication No. 14106/1973 using a phthalocyanine compound in an electrophotographic plate
-30328, 47-30329, U.S. Patent 33579
89, 3492308, 3498784, 359416
There are a series of patent documents such as No. 3, etc., which use β, χ, and π type crystalline phthalocyanine.

However, there has been no phthalocyanine that can be manufactured by a simple method using industrially common raw materials and that has excellent various properties as an electrophotographic plate. As a result of intensive research into the relationship between the crystal form of copper phthalocyanine, manufacturing conditions, and photoconductivity, the present inventor discovered
It has been found that ε-type copper phthalocyanine, which was established in Japanese Patent Application Laid-Open No. 49-59136, has excellent photosensitivity. Further, the present inventors have conducted further studies.

(1) A mixture of (A) and (B) below at 50-200°C.
An electrophotographic plate in which the photoconductor element is copper phthalocyanine having an ε-type crystal form obtained by milling under mechanical strain at preferably 80 to 120°C.

(A) Copper phthalocyanine having an α-type crystal form (B) A phthalocyanine derivative with a substituent introduced into the benzene nucleus
A species or two or more species (2) A mixture of (A) and (B) described in claim 1 at 50 to 20°C, preferably 80°C.
Copper phthalocyanine with ε-type crystal form obtained by milling with mechanical strain at ~120°C and as organic electroactive substances nitrile compounds, polycyclic or heterocyclic nitro compounds, quinones, aromatics It has been found that an electrophotographic plate having a photoconductive layer in which one or more selected from the group amines and their derivatives are dispersed or dissolved in a binder resin is very excellent as an electrophotographic plate.

In other words, it has been found that the manufacturing method known as the manufacturing method for ε-type copper phthalocyanine is most excellent as an electrophotographic plate. α-type copper phthalocyanine is usually 98%
This is a blue pigment obtained by the so-called acid pasting method in which copper phthalocyanine is dissolved in concentrated sulfuric acid and reprecipitated in water. In the present invention, the method for producing α-type copper phthalocyanine is not limited.

As mentioned above, several methods are known for producing ε-type copper phthalocyanine, but α-type copper phthalocyanine is a particularly preferred starting material for use in electrophotographic plates. It should be noted that copper phthalocyanine only needs to have an α-type crystal form at the milling stage, and in the actual process, β-type crystal form is used as a starting material.
Treated in concentrated sulfuric acid using copper phthalocyanate such as a mold,
α-type copper phthalocyanine may be used.

The phthalocyanine derivatives referred to in the present invention are metal-free or metal phthalocyanines having a substituent on one or more of the four benzene 7 nuclei, and simple substituents include an amino group, a nitro group, an alkyl group, Examples include alkoxy groups, cyano groups, and mercapto groups, as well as sulfonic acid groups, carboxylic acid groups, and their metal salts, ammonium salts, and salts with cationic surfactants.

Further, various derivatives having a benzene nucleus and a divalent bonding group, ie, a methylene group, a carbonyl group, a sulfonyl group, an imino group, etc., are also advantageously used. Examples of metal phthalocyanines other than copper include phthalocyanines such as cobalt, nickel, zinc, and tin. In the present invention, 100 parts by weight of α-type copper phthalocyanine and 0.1 to 50 parts by weight of phthalocyanine derivative
A mixture of parts by weight is used, and the mixing ratio is appropriately selected.

Representative examples of devices that use mechanical strain to mill and cause crystal transition include a double Banbury mixer, a ball mill, a sand mill, and an attritor. As the grinding aid, those commonly used as grinding aids for pigments may be used, such as common salt, sodium bicarbonate, and Glauber's salt, but the grinding aid is not necessarily required.
If a solvent is required during grinding, it may be liquid at the temperature during grinding, such as alcoholic solvents, such as glycerin, ethylene glycol, diethylene glycol, or polyethylene glycol, carbitol-based lubricants, and cellosolp-based solvents. , ketone solvents, and the like. Generally, it is desirable to avoid aromatic solvents that convert α-type copper phthalocyanine to β-type. The temperature range in the milling process of the present invention is 50 to 200°C, preferably 80 to 120°C.

Another effective method is to use crystal nuclei as in the usual crystal transition process. After the crystal transition step is completed, the grinding aid, organic silica, etc. are removed by a conventional purification method, and the product is dried to obtain ε-type copper phthalocyanine, which is excellent as a photoconductor element for electrophotographic plates. The ε-type copper phthalocyanine obtained in this way is combined with phenol resin, area resin, melamine resin, furan resin, epoxy resin, silicon resin, polyurethane resin, xylene resin, toluene resin, vinyl chloride mono-vinyl acetate copolymer, vinyl acetate methacrylate. Is the volume resistivity of copolymers, acrylic resins, polycarbonate resins, cellulose derivatives, etc. 107Ω? The photosensitive layer dispersed in the above-mentioned insulating binder resin was coated on a conductive substrate such as an aluminum plate to a thickness of 10 to 50 μm to prepare an electrophotographic plate. Various binder resins are used as the binder resin used in the present invention, as described above, but the 0H content is 8 to 12% (0H content is the percentage of the atomic weight of the 0H group to the molecular weight of the polyol, 17). The polyurethane resin obtained from the branched polyester polyol and hexamethylene diisocyanate has superior electrophotographic properties such as sensitivity and dark decay compared to other binder resins, and the addition of the organic active compound according to the present invention further improves electrophotographic properties such as sensitivity and dark decay. improves.

Furthermore, improvements were made to electrophotographic plates using ε-type copper phthalocyanine, in other words, the photoconductive sensitivity was investigated by using an electron-accepting substance (organic electronically active substance), which is generally called chemical sensitization. However, one or more selected from nitrile compounds, polycyclic or heterocyclic nitro compounds, quinones, aromatic amines, and derivatives thereof are dispersed or dissolved in a binder resin together with ε-type copper phthalocyanine. It has been found that an electrophotographic prefoot using a photoconductive layer has excellent sensitivity, repeatability, printing durability, etc.

Various organic electronically active substances are known, but the present inventors' investigation revealed that tetracyanoethylene,
Nitrile compounds such as tetracyanoquinodimethane, trinitroanthracene, 2,4,7-trinitrofluorein, 2,4,7-trinitrofluorenone, 2,4,5
・The organic electroactive substance selected from polycyclic or heterocyclic nitro compounds such as 7-tetranitrofluorenone, quinones such as anthraquinone, aromatic amines such as tetramethyl-r-phenylenediamine, and derivatives thereof is ε
Particularly good results were shown for type copper phthalocyanine, and for other organic electroactive materials such as naphthalene, anthracene, tetracene, diphenyl, there was no increase in dark decay, decrease in dark resistance of the photoconductive layer, or no effect of other additions. It is not possible to obtain a result that satisfies the function of an electrophotographic plate, such as not being visible.

The present invention provides an electrophotographic plate that can be used practically as a photoconductive layer by using ε-type copper phthalocyanine obtained from α-type copper phthalocyanine and a phthalocyanine derivative by mechanical strain as a photoconductor element, and furthermore, an electrophotographic plate that can be used as a photoconductive layer can be obtained. A fully satisfactory electrophotographic plate was obtained by using the substances in combination.

The composition ratio of the photoconductive layer according to the present invention is 10"O parts by weight of ε-type copper phthalocyanine solids to 1 part by weight of binder resin solids.
00 to 500 parts by weight, and 2 to 40 parts by weight of the organic electroactive substance.

The electrophotographic plate using the photoconductive layer according to the present invention has sufficient practical sensitivity (10 Lux.sec) as electrophotographic properties.
0nd or less), and the image has excellent contrast and clarity.

In addition, the surface of the photosensitive layer is extremely smooth, has high physical strength, and hardly changes due to repeated use. Copying speed is an issue with electrophotographic plates, and there is a desire to increase the speed. Since the electrophotographic plate according to the present invention has excellent sensitivity, it has become possible to copy at a speed of 20 to 30 copies per minute.

Further, it is desirable that the electrophotographic copying machine be made small, and since the electrophotographic plate of the present invention has excellent sensitivity, it is also possible to reduce the exposure area of the electrophotographic plate. In addition, the photosensitive layer using ε-type copper phthalocyanine has excellent flexibility and processability, so it can be used not only for aluminum plates.
It is possible to coat a substrate such as paper and use it as an electrophotographic plate or as a master for offset printing. In the present invention, commonly used additives such as optical sensitizers can also be added.

Next, a method for producing a phthalocyanine derivative according to the present invention will be shown as a reference example.

In the examples, 1 part] indicates parts by weight. Reference Example 1 Copper phthalocyanine is chloromethylated and reacted with various amines to obtain copper phthalocyanine derivatives.

The manufacturing method of these derivatives shown below is described in Japanese Patent Publication No. 32-5083.
No. 1, etc., using a publicly known method. (herein Cupc
represents a copper phthalocyanine residue, and n represents an integer of 1 to 4.

) Reference Example 2 Copper phthalocyanine, phthalimide and formaldehyde were condensed in concentrated sulfuric acid to obtain the following phthalocyanine derivative.

Reference Example 3 By using nitrophthalic acid imide or sulfonated phthalic acid imide instead of phthalic acid imide, monochloroacetic acid chloride, β-chloropropionic acid chloride, acrylic acid chloride or Vinylsulfonyl chloride or the like is reacted in an inert solvent to obtain a compound represented by the general formula (3″) or (f), and this is further reacted with a primary or secondary amino compound to form a compound represented by the general formula (f). A phthalocyanine derivative represented by is obtained.

R2 is a hydrogen atom, an unsubstituted or substituted alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic residue;
1 and R2 may form a ring.

R3 represents a hydrogen atom or a lower alkyl group, and m represents 1 or 2. ) As an example of the derivative obtained in Reference Example 3, Reference Example 4 10 parts of methylolated copper phthalocyanine was mixed with 100 parts of
3 to 10 parts of stearic acid chloride or purinic acid chloride are added, stirred under heating and reflux for 3 hours, cooled, filtered, washed with methanol, and dried to obtain the phthalocyanine shown below. A derivative was obtained.

CUPe+CH2OOCCl7H35)n (4-a
)CuPc÷CH2OOCC9Hl,)n (4-b
) Reference Example 5 Copper phthalocyanine chlorosulfonated by a conventional method, metal-free phthalocyanine (hereinafter referred to as MFPc).

) Nickel phthalocyanine (hereinafter referred to as NiPc) and cobalt phthalocyanine (hereinafter referred to as COPc) were reacted with various amines to obtain the following phthalocyanine derivatives. Reference Example 6 A mixture of 15 parts of copper phthalocyanine, 500 parts of trichlorobenzene, 25 parts of acetyl chloride, and 70 parts of aluminum chloride was stirred at 80 to 90°C for 10 hours, then poured into water, and the solid content was filtered, washed with water, and dried. A compound represented by the following formula was obtained.

CuPc(-COCH2Cl2). By reacting this with amines, various phthalocyanine derivatives represented by the following formulas were obtained.

Reference Example 7 Phthalocyanine derivatives represented by the following general formula are obtained by ring-forming the various phthalocyanine derivatives obtained in Reference Example 6.

(In the formula, R1 and R2 may be a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, or a nitrogen atom and R1 and R2 may form a heterocycle.

) An example of the phthalocyanine derivative obtained in Reference Example 7 is shown.

Next, examples related to the present invention will be shown.

Example 1 100 parts of copper phthalocyanine and 20 parts of the phthalocyanine derivative represented by formula (1-a) were dissolved in 98% sulfuric acid, precipitated in water, filtered, washed with water, and dried to obtain an α-type copper phthalocyanine derivative. 100 parts of this mixture, 200 parts of pulverized common salt, and 80 parts of polyethylene glycol were placed in a furnace and ground at 80 to 100°C for 5 hours.

After removal, it is purified with a 2% dilute sulfuric acid aqueous solution, filtered through the mouth, washed with water,
After drying, ε-type copper phthalocyanine was obtained. Using the obtained ε-type copper phthalocyanine as a photoconductor element, the upper four parts of the above five compositions were kneaded in a porcelain ball mill at room temperature for 30 hours, and then one part of the lower part J was milled. Add as prescribed to make a photosensitive emulsion.

Thereafter, a coating film with a thickness of 20 μm was roll-coated onto an aluminum plate having a thickness of about 100 μm to form a uniform film. Next, the photosensitive layer was cured by baking at 180° C. for 2 hours* to carry out a curing reaction and dry the solvent to prepare a plate. The surface of the photosensitive layer of the thus obtained plate was positively charged by +5KV corona gap 10mm corona discharge.
After 30 seconds of stopping the corona discharge, exposure was performed using a 28540K tungsten light source at an illuminance of 20 Lux.

The maximum surface charge amount was 450 V, and the dark decay rate of the potential after 30 seconds was 9.9% with respect to the potential when 5 seconds had passed after the end of charging. Also, if the sensitivity is the amount of radiation required to lower the surface potential to 10% of the potential immediately before exposure, then the sensitivity of this plate is 10 Lux. It was see0nd. Using this plate, an image was created by the development and transfer method described below. Positive charge is given to the plate by corona discharge 10
A positive film original image is projected at 10L11X for about 1 second using a 0W enlarging tungsten light source to form an electrostatic latent image on the plate, and then a visible image is obtained using negatively charged powder toner.

A high-quality paper is placed on top of it, and a visible image is transferred from the back of the paper using a positively charged carbon brush electrode with an applied potential of 450V.
It was fixed using an infrared lamp. The image obtained by this operation was extremely faithful to the original, and a clear, high-contrast image with no background smudges was obtained. Furthermore, we have created an electrophotographic plate that can withstand repeated practical use. Example 2 ε obtained by processing in the same manner as in Example 1 using copper phthalocyanine and the phthalocyanine derivatives shown in Table 1 below.
Copper phthalocyanine was dispersed in various binder resins (Table 1) in the same manner as in Example 1 to prepare electrophotographic plates.

The maximum surface charge amount, dark decay rate, and sensitivity of this plate were measured in the same manner as in Example 1, and the results are shown in Table 1. As shown in Table 1, a product with excellent physical properties and printing durability well within the practical range was obtained.

It should be noted that ε-type copper phthalocyanine also has a comparatively high dark decay rate of 20 to 40% and a sensitivity of almost 15 or more when produced by a method other than the present invention. Example 3 Using the ε-type copper phthalocyanine obtained in the same manner as in Example 1, the above composition was treated in the same manner as in Example 1, and an electrophotographic plate was prepared. When measured in the same manner as above, the maximum surface charge amount was 480V, the dark decay rate was 10.2%, and the sensitivity was 9.2L0. It was sec0nd.

As shown in the obtained results, the addition of the organic electroactive substance improved the sensitivity and also improved the printing durability. Example 4 The same various phthalocyanine derivative binder resins as in Example 2 were used, and the organic electroactive substances (shown in Table 2) were added in the same manner as in Example 3, with appropriate composition ratios. The obtained electrophotographic plate was measured in the same manner as in Example 1.

Claims (1)

[Claims] 1 ε-type crystal obtained by milling a mixture of the following (A) and (B) at 50 to 200°C, preferably 80 to 120°C, with mechanical strain. An electrophotographic plate using shaped copper phthalocyanine as a photoconductive layer element. (A) Copper phthalocyanine having an α-type crystal form (B) One or more phthalocyanine derivatives having a substituent introduced into the benzene nucleus 2 A mixture of the following (A) and (B) 5
Copper phthalocyanines with ε-type crystal form obtained by milling with mechanical strain at temperatures of 0 to 200°C, preferably 80 to 120°C, as well as nitrile compounds, polycyclic or heterocyclic compounds as organic electroactive substances An electrophotographic plate having a photoconductive layer in which one or more selected from formula nitro compounds, quinones, aromatic amines, and derivatives thereof are dispersed or dissolved in a binder resin. (A) Copper phthalocyanine having an α-type crystal form (B) One or more phthalocyanine derivatives having a substituent introduced into the benzene nucleus