JPH04260048A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body high in transparency and sensitivity to semiconductor laser beams and which is very appropriate as microfilms and the like. CONSTITUTION:The electrophotographic sensitive body using as an electric charge generating material, titanyl phthalocyanine has a photosensitive wavelength region in the near infrared region of >=700nm and a light transmittance of <=0.2 in the visible region.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor suitable as a microfilm or the like.

0002

[Prior Art] In the field of image forming technology, a method of selectively irradiating a uniformly charged photoreceptor with light in accordance with an image signal and developing an electrostatic latent image is generally used to develop an electrostatic latent image. It's called the photographic process. In recent years, in this electrophotographic process, technological development has been progressing to record and preserve the images obtained in a form that can be easily and directly viewed.
For example, applications to microfilm, etc. are being considered.

By the way, when such an electrophotographic process is applied to microfilm, etc., in order to develop and visually recognize an image, toner is applied to a photoreceptor on which an electrostatic latent image has been formed by light irradiation, and a toner image is formed. The toner image is then directly projected onto the photoreceptor with a slide projector or the like. Therefore, the transparency, ie, the light transmittance, and the coloring of the photoreceptor used are important so that a clear image can be obtained when projected. For example, if the light transmittance of the photoreceptor is poor, it will be difficult to reproduce a clear image, and if the photoreceptor is colored, there is a risk that the color tone of the entire image will be modulated.

[0004] For this reason, until now photoreceptors intended for use in such microfilms, etc., have been transparent photoreceptors that use organic polymer semiconductors such as polyvinylcarbazole (PVK) and polyacenaphthene as charge generating agents. Photoreceptors have been used.

However, in the field of electrophotographic processing, semiconductor lasers have come to be widely used as light sources for forming electrostatic latent images in order to miniaturize equipment. Photoreceptors are also required to have high sensitivity in the near-infrared region, which is the wavelength of semiconductor lasers. In this respect, the transparent photoreceptor using PVK, polyacenaphthene, etc. as a charge generating agent mentioned above has a photosensitive region in the ultraviolet region and absorption in the near-infrared region is extremely small, so it is necessary to use a semiconductor laser. It is unsuitable as a transparent photoreceptor for electrophotographic processes.

Therefore, a photoreceptor using a charge transfer complex of PVK and trinitrofluorenone as a charge generating agent, P
VK, polycarbonate etc. and crystal violet,
Transparent photoreceptors with increased photosensitivity in the long wavelength region have been proposed, such as photoreceptors that combine sensitizing dyes such as methylene blue and cyanine. However, the photoreceptor layer of a photoreceptor made of PVK is brittle, and especially when it becomes thick, cracks and peeling occur, making it difficult to handle as is. Furthermore, the sensitivity to semiconductor lasers is not fully satisfactory, making it difficult to form precise images. Furthermore, there are many problems such as the need for a chlorine-based solvent for film formation.

[0007] In addition, a photoreceptor using a thiopyrylium salt as a charge generating agent has been proposed as a photoreceptor sensitive to semiconductor laser wavelengths, but it is difficult to achieve sufficient sensitivity with this photoreceptor. , a large amount of thiopyrylium salt must be contained, resulting in the inconvenience that the photoreceptor is colored and a good color tone cannot be obtained.

[0008]

[Problems to be Solved by the Invention] As described above, conventional electrophotographic photoreceptors have problems such as cracking and lack of transparency.
Since the sensitivity to the semiconductor laser is insufficient, a precise electrostatic latent image cannot be obtained, and a good image cannot be visually recognized when projected with a slide projector or the like. Therefore, the present invention has been proposed in view of such conventional circumstances, and it is possible to form a good electrostatic latent image by irradiation with a semiconductor laser, and to make a clear image visible when projected. The purpose of the present invention is to provide a photoreceptor for electrophotography.

[0009]

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention provides an electrophotographic photoreceptor using titanyl phthalocyanine as a charge generating agent, which has spectral sensitivity characteristics in the near-infrared region of 700 nm or more. It is characterized by having a maximum value and a transmission density of 0.2 or less when measured in the visual filter mode of a Macbeth densitometer.

In the photoreceptor of the present invention, in order to achieve sufficient transparency and sensitivity, the maximum value of the spectral characteristics is in the near-infrared region of 700 nm or more, and the visual filter of the Macbeth densitometer is The transmission density when measured in this mode is 0.2 or less. If the maximum value of the spectral characteristics is not in the near-infrared region of 700 nm or more, sufficient photosensitivity to semiconductor lasers will not be obtained, and there is a high possibility that a good electrostatic latent image will not be formed. In addition, if the transmission density of the photoreceptor exceeds 0.2 when measured in the visual filter mode of the Macbeth densitometer, the transparency of the photoreceptor will be low, and it may be necessary to use a transparent photoreceptor for the purpose of projecting microfilm, etc. There is a risk that it may become unsuitable for use as a. In order to satisfy the above conditions, for example, the thickness of the charge generator layer containing phthalocyanine as a charge generator, the content of phthalocyanine, the crystal structure, etc. may be adjusted.

As shown in FIG. 1, the photoreceptor of the present invention includes, for example, a charge generation layer 2 containing titanyl phthalocyanine as a charge generation agent on a transparent conductive support 1 made of polyethylene terephthalate or the like sputtered with indium tin oxide.
and a charge transport layer 3 made of a charge transport agent and a binder are laminated.

The charge generation layer 2 may be a coating film in which fine crystals of titanyl phthalocyanine are dispersed in a suitable binder, or a vapor deposited film in which titanyl phthalocyanine is deposited by a method such as vacuum evaporation. There is no problem even if it is. Further, the thickness of the charge generation layer is preferably 2 μm or less, more preferably 0.01 to 1.0 μm. When the charge generation layer 2 is a coating film containing titanyl phthalocyanine, examples of the binder include polyester resin, polyvinyl chloride resin, acrylic resin, methacrylic resin, polystyrene resin, butyral resin, epoxy resin, phenol resin, and polycarbonate resin. Polymer binders such as can be used. Mixing ratio when mixing these polymer binders and titanyl phthalocyanine (titanyl phthalocyanine crystals: polymer binder)
The weight ratio is preferably 1:0.1 to 1:10, more preferably 1:0.1 to 1:5.

On the other hand, as the charge transport agent contained in the charge transport layer 3, any material can be used as long as it has charge transport properties and does not impair the transparency of the photoreceptor. Examples of such compounds include triphenylmethane compounds represented by general formula 1, and specific examples include
Compounds represented by formula 24, or hydrazone compounds represented by general formula 25, specific examples of which include compounds represented by formulas 27 to 38, or hydrazone compounds represented by general formula 26. BA 39-73
Examples include compounds shown in the following.

[Chemical formula 1]

[In the formula, R1, R2, R3, R4
represents the same or different lower alkyl group or a substituted or unsubstituted benzyl group, R5 and R6 represent the same or different hydrogen atom, methyl group or methoxy group, and R7 represents an alkyl group having 6 or less carbon atoms or a substituted or unsubstituted benzyl group. phenyl or naphthyl group]

[Case 2]

[Chemical formula 3]

[C4]

[C5]

[C6]

[C7]

[Chemical formula 8]

[Chemical formula 9]

[Chemical formula 10]

[Chemical formula 11]

[Chemical formula 12]

[Chemical formula 13]

[Chemical formula 14]

[Chemical formula 15]

[Chemical formula 16]

[Chemical formula 17]

[Chemical formula 18]

[Chemical formula 19]

[C20]

[C21]

[C22]

[C23]

[C24]

[C25]

[In the formula, R1 R2 represents the same or different lower alkyl group, benzyl group, substituted or unsubstituted phenyl group, and R3 represents a hydrogen atom, a lower alkyl group,
Indicates lower alkoxy group, benzyloxy group]

[C26]

[In the formula, R4 represents an alkyl group having 1 to 6 carbon atoms, a phenyl group, a naphthyl group, or a benzyl group, and R5
and R6 are the same or different and represent an alkyl group having 1 to 6 carbon atoms, phenyl group, tolyl group, methoxyphenyl group, naphthyl group, benzyl group, or R5 and R6 together represent 1, Forms a 2,3,4-tetrahydroquinone ring]

[C27]

[C28]

[C29]

[C30]

[Chemical formula 31]

[C32]

[Chemical formula 33]

[C34]

[C35]

[C36]

[C37]

[C38]

[C39]

[C40]

[C41]

[C42]

[C43]

[C44]

[C45]

[C46]

[C47]

[C48]

[C49]

[C50]

[C51]

[C52]

[C53]

[C54]

[C55]

[C56]

[C57]

[C58]

[C59]

[C60]

[C61]

[C62]

[C63]

[C64]

[C65]

[C66]

[C67]

[C68]

[C69]

[C70]

[C71]

[C72]

[C73]

[0017] As the binder for dispersing the charge transport agent, any binder used in dispersing titanyl phthalocyanine in the charge generation layer 1 can be used. The thickness of the charge generation layer is preferably 3
50 μm, more preferably 5 to 30 μm.

[0018]

[Action] Titanyl phthalocyanine is a photosensitive material that has low absorption in the visible light range. Therefore, an electrophotographic photoreceptor using titanyl phthalocyanine as a charge generating agent can be used as a semiconductor laser without impairing transparency by adjusting, for example, the thickness of the charge generating layer, the content of titanyl phthalocyanine, and the crystal structure. It is possible to ensure sensitivity in the near-infrared wavelength region. In the present invention, in an electrophotographic photoreceptor using titanyl phthalocyanine as a charge generating agent, the maximum value of spectral characteristics is in the near-infrared region of 700 nm or more, and when measured in the visual filter mode of a Macbeth densitometer. The transmission density is adjusted to be 0.2 or less, and it has high transparency and high sensitivity in the near-infrared region. Therefore, a good electrostatic latent image is formed by the semiconductor laser, and a clear image is visually recognized when projected after development.

[0019]

EXAMPLES The present invention will be explained below based on specific experimental results.

Example 1 This example is an example of an electrophotographic photoreceptor in which a coating film containing titanyl phthalocyanine was formed as a charge generation layer.

First, 35 parts of butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name BL-1) was mixed with 1 part of tetrahydrofuran.
A binder solution was prepared by dissolving 450 parts. Then, 10 parts of titanyl phthalocyanine crystals were added to this binder solution and dispersed together with glass beads (φ1 mm) in a vibration mill for 2 hours to obtain a charge generating agent solution. This charge generating agent solution is preliminarily mixed with indium tin oxide (
ITO) was applied onto a sputtered polyester film using a wire bar and dried to form a charge generation layer with a thickness of about 0.5 μm. Next, 10 parts of the triphenylmethane derivative shown in Chemical Formula 7 was dissolved in 100 parts of dichloroethane together with 10 parts of polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name Z-200) to prepare a charge transport agent solution. The agent solution was applied onto the charge generation layer using a doctor blade and dried at 80° C. to form a charge transport layer, thereby producing a photoreceptor.

Next, the spectral sensitivity characteristics of the produced photoreceptor and the transmission density in the visual filter mode of a Macbeth densitometer were measured. As a result, the photoreceptor had an absorption maximum near 800 nm, a transmission density of 0.1, and high transparency.

Example 2 This example is an example of an electrophotographic photoreceptor in which a vapor-deposited film of titanyl phthalocyanine was formed as a charge generation layer.

A titanyl phthalocyanine film is formed on a polyester film sputtered with ITO in advance by a vacuum evaporation method so that the absorbance at the maximum absorption wavelength in the near-infrared region of 700 nm or more is 0.4 to form a charge generation layer. did. Next, a charge transport layer was formed on the charge generation layer by the same method as in Example 1 to produce a photoreceptor.

Next, the spectral sensitivity characteristics of the produced photoreceptor and the transmission density in the visual filter mode of a Macbeth densitometer were measured. As a result, the photoreceptor had an absorption maximum near 800 nm, a transmission density of 0.12, and high transparency. The photoreceptors produced in Examples 1 and 2 as described above were charged by applying −6 kV corona discharge for 5 seconds, and after measuring the surface potential V0, they were held in a dark place for 5 seconds. And wavelength 78
The power density of 0nm semiconductor laser light on the photoreceptor is 1
．． The half-reduced exposure energy E required to attenuate the surface potential to 1/2 by irradiating it at 5 mW/cm2
1/2 (μJ/cm2) and semiconductor laser light 20m
The surface residual potential VR (V) after sec irradiation was measured. Table 1 shows the measurement results of V0, E1/2 and VR.

[Table 1]

From Table 1, it can be seen that the transparent photoreceptors produced in Examples 1 and 2 showed good values for both half-exposure energy and surface residual potential, and had high sensitivity to semiconductor lasers. I know that there is. Therefore, it was shown to be suitable as a transparent photoreceptor.

[0027]

Effects of the Invention As is clear from the above explanation, the present invention provides an electrophotographic photoreceptor using titanyl phthalocyanine as a charge generating agent, in which the maximum value of the spectral sensitivity characteristic is in the near-infrared region of 700 nm or more. It has a transmission density of 0.2 or less when measured in the visual filter mode of a Macbeth densitometer, so it has high transparency and high sensitivity to semiconductor lasers. Therefore, a precise electrostatic latent image can be obtained using a semiconductor laser, and a clear image can be seen when projected, making it possible to obtain good characteristics when used as a microfilm etc. .

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of a photoreceptor of the present invention.

Claims (1)

[Claims] Claim 1: An electrophotographic photoreceptor using titanyl phthalocyanine as a charge generating agent, which has a maximum value of spectral sensitivity in the near-infrared region of 700 nm or more, and which was measured in the visual filter mode of a Macbeth densitometer. 1. A photoreceptor for electrophotography, which has a transmission density of 0.2 or less.