JPH0815881A - Image forming method - Google Patents

Abstract

PURPOSE:To form an image with high sensitivity and high resolution without fatigue or deterioration in repeated processes of image forming by using a photoreceptor having a photosensitive layer containing a specified perylene pigment and exposing the photoreceptor by using a semiconductor laser which generates visible beam. CONSTITUTION:In the image forming method to form an image by repeating processes of charging an electrophotographic photoreceptor, exposing, developing and transferring, the photoreceptor used has a photosensitive layer containing a perylene pigment expressed by formula I or II having a specified crystalline state on a conductive supporting body. The exposing process is performed by using a semiconductor laser which generates visible beam. In formula, Z is a group of atoms necessary to form a substd. or unsubstd. heteroring. The specified crystalline type of the perylene pigment has the Bragg angle 2theta in the X-ray diffraction spectrum for Cu-Ka ray at 6.3+ or -0.2+ or -, 12.4+ or -0.2 deg., 25.3+ or -0.2 deg., 27.1+ or -0.2 deg. and the max. peak intensity at 12.4+ or -0.2 deg. with >=0.65. half value width. Further, the crystal does not has a sharp peak at 11.5+ or -0.2 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for forming an image by using a visible light semiconductor laser as an exposure device of a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, an image in which a dot image is formed by applying a uniform charge on an electrophotographic photosensitive member and then digitally exposing it with a laser beam modulated by an image signal from an external signal source such as a scanner or a computer. Forming methods are known. As a device for outputting the laser beam, for example, a He-Ne gas laser or a He-Cd gas laser is known, but any of these laser beam oscillators has a large device and consumes a large amount of energy. There is a drawback called.

Therefore, a semiconductor laser which is small in size, low in cost and consumes less energy has come to be used as an exposure device for a digital copying machine or a printer.

On the other hand, an electrophotographic photosensitive member having a light absorption characteristic in the visible light region of 400 to 700 nm and having a high sensitivity characteristic is disclosed in, for example, JP-A-57-177151, Se-Te.
A photoreceptor having a vapor-deposited photosensitive layer made of an -As alloy is known. However, Se, Te, As, etc. in the photosensitive layer have the drawbacks that they are highly toxic, are harmful to the environment, are difficult to process, are expensive, and have poor moisture resistance.

Therefore, development of an organic photoconductor which is harmless, easy to process, low cost, and excellent in moisture resistance is being advanced. Among them, the charge generating function is the charge generating substance and the charge transporting function is the charge transporting substance. The function-separated type organic photoconductor that has been shared shows excellent characteristics. In such an organic photoconductor, the degree of freedom in selecting the charge generating substance and the charge transporting substance is large, and a substance capable of sufficiently exhibiting the above-mentioned functions can be selected from a wide range in view of desired characteristics. Examples of the charge generating substance that has sufficient light absorption characteristics for visible light and can exhibit high sensitivity characteristics include, for example, JP-A-50-7.
No. 0232, JP-A-58-144358, JP-A-60-196772, bisazo pigments described in JP-A-58-11398 and JP-A-58-1.
The phthalocyanine pigments described in JP-A No. 82639 and JP-A No. 64-17060 are known.

[0006]

However, the above-mentioned semiconductor laser oscillates in the infrared region exceeding 700 nm from the viewpoint of device life and output stability, as described in, for example, JP-A-57-53754. Those having a wavelength are used. For example, a 780 nm semiconductor laser is mainly used in digital copying machines, printers and the like. By the way, digital copiers and printers generally have a pixel density of 400d.
An image of pi or more is required, and when using the infrared oscillation laser, there is a problem that when trying to increase the resolution, the beam wavelength exceeds the limit of resolution and a clear image cannot be obtained. .

However, in order to obtain an organic photoconductor having sufficient photosensitivity in the visible region and excellent electrophotographic performance for solving this problem, development of a charge generating substance for the photoconductor is particularly required. There is a problem that it is difficult.

Further, when the image is formed by the copying machine or the printer, there is a problem that the light is not visible because the light is not visible and the eyes are damaged.

Therefore, the visible region of 700 nm or less, for example, 400 to 50
Blue light semiconductor laser with main oscillation wavelength at 0 nm, 5
Development of an image forming apparatus or an image forming method using a green light semiconductor laser having a main oscillation wavelength of 01 to 600 nm or a red light semiconductor laser having a main oscillation wavelength of 601 to 700 nm is desired.

On the other hand, the above-mentioned bisazo pigments or phthalocyanine pigments used for organic photoreceptors are capable of absorbing visible light and exhibiting high-sensitivity characteristics, but on the other side, repeated image formation over a long period of time causes fatigue deterioration. There's a problem. The above-mentioned problem of fatigue deterioration is usually aggravated as the sensitivity of the photoconductor becomes higher, and particularly when a laser having a large energy is used as the exposure means.

The present invention has been proposed in view of the above circumstances, and an object thereof is to use a visible light semiconductor laser in place of the conventional infrared light semiconductor laser and to absorb visible light in combination therewith. Another object of the present invention is to provide an image forming method capable of forming an image with high sensitivity and high resolution without fatigue deterioration in the process of repeated image formation by using a photoconductor having high sensitivity and high durability.

[0012]

The above-mentioned object is to provide an image forming method for forming an image on a electrophotographic photosensitive member by repeating a process including respective steps of charging, exposing, developing and transferring. A photosensitive member comprising a conductive support and a photosensitive layer containing a perylene pigment represented by the following general formula [1] or general formula [2] and having the following crystal form is used. This is achieved by an image forming method characterized by being performed by a semiconductor laser for outputting.

[0013]

Embedded image

(In the formula, Z represents an atomic group necessary for forming a substituted or unsubstituted heterocycle.) Crystal form of perylene pigment: Bragg angle 2θ of X-ray diffraction spectrum with respect to Cu-Kα line is 6.3. ± 0.2 °, 12.4 ± 0.2
With peaks at °, 25.3 ± 0.2 ° and 27.1 ± 0.2 °, has a maximum peak at 12.4 ± 0.2 °, half-width of the peak is 0.65 ° or more, and a clear peak at 11.5 ± 0.2 °. I don't have it.

In the general formulas [1] and [2] representing the perylene pigment having the above-mentioned specific structure, preferred examples of the aromatic ring represented by Z include, for example, benzene ring, naphthalene ring, anthracene ring and phenanthrene. Examples thereof include a ring, a pyridine ring, a pyrimidine ring, a pyrazole ring and an anthraquinone ring, and a benzene ring or a naphthalene ring is particularly preferable. The aromatic ring represented by Z may be substituted, and as the substituent, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an asyl group, an acyloxy group, an amino group, a carbamoyl group, a halogen atom,
Examples thereof include a nitro group and a cyano group.

In the image forming method of the present invention, a semiconductor laser output modulated by an image signal from an external signal source such as a scanner or a computer is written on a photoconductor to form an electrostatic latent image, and the latent image is normalized or inverted. By an image forming method, which is developed to form a dot-shaped toner image, which is transferred and fixed on a transfer material to form a dot-shaped image.

In the present invention, as the semiconductor laser,
A blue light semiconductor laser having a main oscillation wavelength of 400 to 500 nm, a green light semiconductor laser having a main oscillation wavelength of 501 to 600 nm or a red light semiconductor laser having a main oscillation wavelength of 601 to 700 nm is selected and used. By using an organic photoconductor containing a perylene pigment having a specific chemical structure and a crystalline structure in combination as a charge generating substance, even if it is repeatedly used, the photoconductor does not deteriorate due to fatigue and has high sensitivity and high durability. It is characterized in that it enables the formation of sharp dot images with high resolution.

The layer structure of the organic photoreceptor is as shown in FIG. 1, for example. In the figure, 1 is a conductive support, 2
Is a charge generation layer (CGL), 3 is a charge transport layer (CTL),
5 is an intermediate layer, 6 is a charge transport material (CTM), 7 is a charge generating material (CGM), 4, 4'and 4 "are CG, respectively.
The photosensitive layers of L-CTL laminated type, CTL-CGL laminated type, and single layer type in which CTM and CGM coexist are shown.

As a typical example, the photoconductor of FIG. 1C will be selected and its detailed structure will be described. First, as the conductive support 1, a metal plate including an alloy, a metal drum or a conductive polymer, a thin metal layer such as aluminum, palladium, or gold including a conductive compound or alloy such as indium oxide is applied, vapor-deposited or Laminated paper with conductive surface,
Examples include plastic drums and plastic films. As the intermediate layer 5 such as the adhesive layer or the barrier layer, for example, a copolymer type or modified type alcohol-soluble polyamide, an organic polymer substance such as polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, or aluminum oxide is usually used.
The film thickness is less than or equal to μm, particularly less than or equal to 1 μm.

The CGL 2 provided on the intermediate layer 5 contains a specific perylene pigment having a high light absorption property in the entire visible region, whereby it is suitable for image formation using a visible light semiconductor laser, A sensitive and highly durable photoconductor can be obtained. The CGL2 is dispersed, for example, by a disperser such as a mixer or a grinder in a dispersion medium in which a CGM composed of the perylene pigment and, if necessary, a binder resin are dissolved, and the obtained dispersion is coated on the intermediate layer 5. .

As another method, the pigment may be vacuum-deposited on the support 1 or the intermediate layer 5 to form CGL2.

Specific examples of the compound of the perylene pigment of the present invention are shown below, but the present invention is not limited thereto.

[0023]

Embedded image

These exemplified compounds are described in, for example, JP-A-SHO.
It can be synthesized by the methods described in JP-A-49-128734 and JP-A-59-59686.

Generally, CGM has high purity and
It is required that the fine particles are uniformly dispersed in L2, and therefore, the perylene pigment according to the present invention is purified by sublimation. Further, since it is a fine dispersion in a fine particle state, when it is dispersed by stirring with a strong shearing force, the crystal is broken and damaged, and the original high-sensitivity characteristics are lost. Therefore, it is preferable that the perylene pigment according to the present invention is subjected to acid paste treatment. .

As the solvent or dispersion medium used for forming CGL2 of the present invention, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methylethylketone, methyl Isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,
2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve and the like can be mentioned. The present invention is not limited to these, but when a ketone solvent is used, the sensitivity, potential change during repeated use and the like are further improved. Further, these solvents may be used alone or as a mixed solvent of two or more kinds.

As the binder resin used for CGL2, polyamide, polyurethane, polyester,
Epoxy resin, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polystyrene and the like are used. The present invention is not limited to these, but when a polyvinyl butyral resin is used, the sensitivity, potential change during repeated use and the like are further excellent. These binder resins can be used alone or
It can be used as a mixture of two or more species.

In the CGL2 formed as described above, the weight ratio of CGM to the binder is preferably 10
It is 0: 0 to 1000.

If the content ratio of CGM is less than this, the photosensitivity is low and the residual potential is increased. When CTM is contained in CGL2, the weight ratio of CGM to CTM is preferably 10: 1 to 1000, and particularly preferably 10: 1 to 100.

The thickness of the CGL2 formed is preferably 0.01 to 10 μm.

As a coating method, a usual method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method or a bead coating method can be used.

Next, the CTL3 in the present invention will be described.

CTL3 is formed of CTM and a binder resin. The CTM used in the present invention is not particularly limited, but examples thereof include oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives,
Triazole derivative, imidazole derivative, imidazolone derivative, imidazolidine derivative, bisimidazolidine derivative, styryl compound, hydrazone compound, benzidine compound, pyrazoline derivative, stilbene compound, amine derivative, oxazolone derivative, benzothiazole derivative, benzimidazole derivative, quinazoline derivative, Examples thereof include benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene and the like.

As the binder resin used for CTL3,
It can be used by appropriately selecting from a wide range of insulating resins. Preferred binder resins include polyester resins,
Methacrylic resin, acrylic resin, polyvinyl chloride resin,
Polyvinylidene chloride resin, polystyrene resin, polycarbonate resin, polyvinyl acetate resin, styrene-
Butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, poly-N-vinylcarbazole, polyvinyl acetal (eg, Polyvinyl butyral) and the like.

These binder resins may be used alone or in admixture of two or more.

The compounding ratio of the binder resin and CTM is 100: 20-2.
00, more preferably 100: 30 to 150. CTL3
The film thickness is 1 to 100 μm, and more preferably 5 to 50 μm. As a coating method, a method similar to CGL2 can be used.

Further, various additives may be incorporated for the purpose of improving the function of CTL3.

Next, FIG. 2 schematically shows an example of an exposure apparatus using a semiconductor laser beam used in the image forming method of the present invention. In FIG. 2, the laser beam oscillator 11
The laser beam output from the device is modulated by the acousto-optic modulator 12 in accordance with the external signal S, and the modulated beam obtained is deflected by the polygon mirror 13 composed of an octahedral rotating polygon mirror to form an f-θ lens for imaging. The photosensitive body 10 is scanned at a constant speed by the deflected beam 15 through 14.

Numerals 16 and 17 are mirrors, and numeral 18 is a collimator lens for adjusting the beam diameter.

In the present invention, the laser beam oscillator 11 is used.
As a substitute for the conventional infrared semiconductor laser beam,
A characteristic is that a blue light semiconductor laser beam having a main oscillation wavelength of 400 to 500 nm, a green light semiconductor laser beam having a main oscillation wavelength of 501 to 600 nm, or a red light semiconductor laser beam having a main oscillation wavelength of 601 to 700 nm is used. is there.

The blue light, green light or red light semiconductor laser is already known in the technical field of displays, bar code readers, video discs and the like.

As a blue light semiconductor laser, for example, one having a main oscillation wavelength region at 489.9 nm developed by Sony Corporation is known, and the laser is a Group 2 element Zn, Mg and Group VI of the periodic table. Oscillation is performed using a four-element element of elements S and Se.

Also, for example, 429 nm developed by Matsushita Electric Industrial Co., Ltd.
A laser having a main oscillation wavelength region is known, and the laser is supposed to output the second harmonic of 429 nm from an infrared laser beam of 858 nm using an SHG element of lithium tantalate.

Regarding the green light semiconductor laser, for example, one having a main oscillation wavelength region at 525 nm developed by 3M Company in the United States is known, and the laser is Mg.
It oscillates using an element containing a Group 2 element and a Group 4 element of the periodic table excluding.

Next, regarding the red light semiconductor laser, for example, which has a main oscillation wavelength region at 633 nm developed by Hitachi, Ltd., and has a trade name HL6 for bar code readers.
Known for the 312G.

An image forming method by the image forming apparatus of FIG. 3 incorporating the photoconductor and the visible light semiconductor laser according to the present invention will be described below.

In the figure, 10 is a drum-shaped photoconductor having a photosensitive layer using a specific perylene pigment as the CGM and rotating in the direction of the arrow, 20 is a charger for uniformly charging the surface of the photoconductor, 21
Is an exposure laser beam from the visible light semiconductor laser exposure apparatus of FIG. For example, Y (yellow), M (magenta), C (cyan), and BK (black) signals S are sequentially output to the modulator 12 of the laser exposure apparatus for each rotation of the image forming body (photoreceptor). Then, the laser beam from the laser oscillator 11 is modulated, and the modulated laser beam is sequentially written on the photoconductor through the collimator lens 18, the polygon mirror 13, and the f-θ lens 14, and the corresponding electrostatic is recorded. A latent image is formed. The latent image is sequentially developed by the non-contact reversal development method by the Y, M, C and BK color developing devices 22, 23, 24 and 25 for each rotation of the photoconductor 10 so that Y, M, and The C and BK toner images are formed in an overlapping manner, and after being easily transferred by the transfer static eliminator 26 and the exposure lamp 27, they are transferred to the transfer paper P by the transfer pole 28 and fixed to form a color image. .

After the transfer, the photoconductor 10 is destaticized by the destaticizing device 29 and then destaticized by the cleaning device 30 to prepare for the next image formation.

Although the image forming method of the present invention has been described above using the color image forming apparatus as an example, a monochrome image forming method may be used.

Although the reversal development method is used in the color image forming method, it may be regular development, and the monochrome image forming method may be either regular development or reversal development, and either contact development or non-contact development may be performed. It may be.

In the image forming method, since the specific perylene pigment according to the present invention has photosensitivity in the entire visible region as shown in FIG. 4, the semiconductor laser may be any one of the blue light, green light and red light lasers. It is also possible to form a sharp dot image with high sensitivity and high durability and without fatigue deterioration.

[0052]

EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereto.

[Production of Photoreceptor] (Synthesis of Exemplified Compound A-1) Perylene-3,4,9,10-tetracarboxylic dianhydride 39.2 g, o-phenylenediamine 32.4
g and 800 ml of α-chlornaphthalene were mixed and reacted at 260 ° C. for 6 hours. After cooling, the precipitated crystals were collected by filtration and repeatedly washed with methanol. Exemplified compound A-1 was synthesized by heating and drying.

(Sublimation Purification Treatment) The exemplified compound A-1 obtained as described above was purified by sublimation under heating conditions of 500 ° C. under a pressure of 5 × 10 ^{−4 to} 5 × 10 ⁻³ torr. . Volatile impurities were removed using a shutter. The obtained purified crystals were subjected to the same sublimation treatment once more to be further purified. A product obtained by repeating such a sublimation purification operation twice is referred to as a sublimated product (SUB) of Exemplified Compound A-1.

(Acid Paste Treatment) A solution prepared by dissolving 20 g of the sublimated and purified Exemplified Compound A-1 in 600 ml of concentrated sulfuric acid was filtered through a glass filter, and then dropped into 1200 ml of pure water for precipitation. This was collected by filtration, washed thoroughly with pure water, and then dried. The thus obtained product is referred to as an acid paste-treated product (AP product) of Exemplified Compound A-1.

(Preparation of Photoreceptor 1) 30 g of copolyamide resin CM8000 (Toray Industries, Inc.) was put into a mixed solvent of 900 ml of methanol and 100 ml of 1-butanol and dissolved. This solution was applied onto an aluminum drum having an outer diameter of 181.9 mm and a length of 353 mm by dip coating to form an intermediate layer having a thickness of 0.5 μm. Subsequently, 6 g of polyvinyl butyral resin S-REC BLS (Sekisui Chemical Co., Ltd.) was added to methyl ethyl ketone (Kanto Chemical Co., Ltd.).
Co., Ltd.), dissolved in 1000 ml, and further mixed with 28 g of AP product of Exemplified Compound A-1 obtained by the above-mentioned method, and then dispersed with 2000 g of glass beads having a diameter of 1 mm for 15 hours using a sand mill (SD). , A dispersion was obtained. This dispersion was applied onto the intermediate layer by dip coating to form a CGL having a thickness of 0.5 μm.

At this time, the obtained dispersion liquid was applied onto a glass plate a plurality of times and dried to form a dry solid film having a thickness of about 200 μm, and X-ray diffraction measurement using CuKα rays was performed. Bragg angle 2θ is 6.3 °, 12.4
It was found that the crystals had peaks at °, 25.3 °, and 27.1 °, had the maximum peak intensity at 12.4 °, and at the same time had a half-value width of 0.65 ° and showed no clear peak at 11.5 °. It was

Then, 200 g of the following compound T and polymer B 2
00 g was dissolved in 1000 ml of dichloromethane (Kanto Chemical Co., Inc.). Using this solution, a CTL having a thickness of 20 μm was formed on the CGL by dip coating.

Finally, heating and drying was carried out at 100 ° C. for 1 hour to prepare a photoreceptor 1 in which the intermediate layer, CGL and CTL were sequentially laminated. The X-ray diffraction spectrum (XRD) is shown in FIG.
It is shown in (a).

[0060]

[Chemical 4]

(Preparation of Photoreceptor 2) 1,2-dichloroethane was used in place of the solvent methyl ethyl ketone of the dispersion 1 and the dispersion 2 was obtained by dispersing the glass beads in the dispersion sand mill for 2500 hours for 20 hours. A photoconductor 2 was obtained in the same manner as the photoconductor 1 except that CGL was formed by using.

When the X-ray diffraction spectrum of the dispersion 2 was measured, as shown in Table 1, the peak intensity at 12.4 ° was the maximum, the full width at half maximum of the peak was 0.94 °, and a clear peak was found at 11.5 °. It turned out not to show.

(Preparation of Photoreceptor 3) Tetrahydrofuran was used instead of the solvent methyl ethyl ketone in the dispersion liquid 1, and the amount of glass beads in the dispersion sand mill was 1500 g.
Then, a photoconductor 3 was obtained in the same manner as the photoconductor 1 except that CGL was formed using the dispersion liquid 3 obtained by dispersing for 10 hours.

When the X-ray diffraction spectrum of the dispersion 3 was measured, as shown in Table 1, the peak intensity at 12.4 ° was the maximum, the half width of the peak was 0.68 °, and a clear peak was found at 11.5 °. It turned out not to show.

(Preparation of Photoreceptor 4) Dispersion liquid 1 was dispersed for 5 hours by using an ultrasonic disperser (US) in place of the sand mill as dispersion means, and the obtained dispersion liquid 4 was used for CGL.
Comparative photoconductor 4 was obtained in the same manner as photoconductor 1 except for the formation.

When the X-ray diffraction spectrum of the dispersion 4 was measured, as shown in Table 1, the peak intensity at 12.4 ° was the maximum, and the full width at half maximum of the peak was 0.60 ° and a clear peak at 11.5 °. Turned out to show.

(Production of Photoreceptor 5) CGL is formed by using Dispersion 5 containing Sublimation Product (SUB) of Exemplified Compound A-1 in place of AP Product of Exemplified Compound A-1 of Dispersion 1 above. A comparative photoconductor 5 was obtained in the same manner as the photoconductor 1 except for the above.

When the X-ray diffraction spectrum of the dispersion 5 was measured, as shown in Table 1, it did not have the maximum peak intensity at 12.4 °, but had the maximum peak intensity at 27.1 °, and the full width at half maximum of the 12.4 ° peak was It was found that at 0.68 °, there was no clear peak at 11.5 °.

The X-ray diffraction spectrum (XRD) measured using the dispersion liquid 5 in the same manner as in the case of the photoconductor 1 is shown in FIG.

[0070]

[Table 1]

[Image forming test] <Measurement of electric potential characteristics> A blue semiconductor laser L was used as a laser device.
With _1, formed by mounting the photoreceptor 1 as a photosensitive member Konica9
Using a modified machine of 028 (manufactured by Konica Co., Ltd.), the potential characteristics were measured the first time and 100,000 times when the electrification-exposure-static elimination was repeated over 100,000 times.

This measurement is carried out in an atmosphere of 20 ° C. and 60% RH. Each developing device for Y, M, C and BK is removed, the transfer device and the cleaning device are deactivated, and an electrometer is placed at the position of the Y developing device. With the probe installed, the dark potential V _H and the light potential V _L
And the residual potential V _r were measured, and the results are shown in Table 2.

<Measurement of resolving power> The modulator (see FIG. 2) of the modified machine is turned on / off for each pixel of FIG. 6 (a) (black line is about 8 mm at 400 dpi) and turned on for every 2 pixels. -OFF (6 black lines / mm)
And 3 kinds of pattern signals of ON-OFF for every 3 pixels (black line about 4 lines / mm) are output from an external memory, and the photoconductor 1 is beam-scanned by the laser L ₁ modulated by the signals. An electrostatic latent image corresponding to the three types of pattern signals was formed, and the latent image was developed by a BK developing device to form a print image. This process was repeated 10,000 times, and the resolution (MTF) of the print images of the first print and the 10,000th print was measured.

As for the MTF, as shown in FIG. 6B, the minimum density D ₁ and the maximum density D ₂ of the printed image were measured with a microdensitometer manufactured by Macbeth, and the formula MTF =
It was calculated by {(D ₂ −D ₁ ) / (D ₁ + D ₂ )} × 100%.

The measurement of D ₁ and D ₂ was performed by using the printed image 2
MTF is measured for all black lines within the mm width and MTF is calculated from the average value.
I asked.

In the evaluation of the resolving power of the photoreceptor 1, 50% or more of the MTF values of the respective copy images obtained as described above are “◯” and less than 50% are “O”. X ”,
The results were shown in Table 2 in the "○" and "×" methods.

<Measurement of Color Image Quality> A color document is placed on the document table of the modified machine, and color copying is performed 10,000 times, and the image quality of the first copy and the 10,000th copy is evaluated as “◯”, “×”. "
The results are shown in Table 2.

(Examples 2 to 5 and Comparative Examples 1 to 3) Example 1 except that the photosensitive member and the semiconductor laser were changed as shown in Table 2.
In the same manner as above, measurement of potential characteristics upon repeated charging, exposure and charge removal, measurement of resolving power and color image actual copying test were conducted, and the results are shown in Table 2.

[0079]

[Table 2]

From Table 2, the examples in which the photoconductor of the present invention and the visible light laser are used in combination have excellent potential characteristics, resolution and color image quality, but a photoconductor which does not belong to the present invention is used or red It is understood that in the comparative example using the external light laser, the potential characteristics are poor, and particularly the resolution and color image quality after repeated use are poor.

[0081]

According to the photoconductor of the present invention and the image forming method of the present invention using the photoconductor and a visible light semiconductor laser,
In the process of image formation, the high-potential and high-sensitivity characteristics of the photoreceptor are maintained, the residual potential does not increase, and high-resolution images of high quality can be stably obtained over a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a layer structure of a photoconductor.

FIG. 2 is a schematic view of a laser device.

FIG. 3 is a sectional view showing an example of an image forming apparatus.

FIG. 4 is a graph showing spectral absorption characteristics of a perylene pigment.

FIG. 5 (a) is an X-ray diffraction spectrum of the perylene pigment of the present invention. (B) An X-ray diffraction spectrum diagram of a comparative perylene pigment.

FIG. 6A is a test pattern for MTF measurement. (B) Printed image of the test pattern for MTF measurement. (C) A graph showing the relationship between pixel density and MTF.

[Explanation of symbols]

 1 Conductive Support 2 Charge Generation Layer (CGL) 3 Charge Transport Layer (CTL) 4, 4 ', 4 "Photosensitive Layer 10 Photosensitive Body 11 Laser Oscillator 12 Modulator 13 Polygon Mirror 14 f-θ Lens 20 Charger 22 , 23, 24, 25 Developing device 26 Static eliminator 27 Static erasing lamp 28 Transfer electrode 29 Static erasing device 30 Cleaning device

Claims (5)

[Claims] 1. An image forming method for forming an image by repeating a process including a step of charging, exposing, developing and transferring on an electrophotographic photosensitive member, wherein as the photosensitive member, the following general formula is provided on a conductive support. Represented by [1] or the general formula [2],
An image forming method, characterized in that a photosensitive body provided with a photosensitive layer containing a perylene pigment having the following crystal form is used, and the exposure is performed by a semiconductor laser that outputs visible light. Embedded image (In the formula, Z represents an atomic group necessary for forming a substituted or unsubstituted heterocycle.) Crystal form of perylene pigment: Bragg angle 2θ of X-ray diffraction spectrum with respect to Cu-Kα line is 6.3 ± 0.2 °. , 12.4 ± 0.2
With peaks at °, 25.3 ± 0.2 ° and 27.1 ± 0.2 °, has a maximum peak at 12.4 ± 0.2 °, half-width of the peak is 0.65 ° or more, and a clear peak at 11.5 ± 0.2 °. I don't have it. 2. The image forming method according to claim 1, wherein the exposure is performed by a semiconductor laser that outputs a laser beam having a main oscillation wavelength of 400 to 500 nm. 3. The image forming method according to claim 1, wherein the exposure is performed by a semiconductor laser that outputs a laser beam having a main oscillation wavelength of 501 to 600 nm. 4. The image forming method according to claim 1, wherein the exposure is performed by a semiconductor laser that outputs a laser beam having a main oscillation wavelength of 601 to 700 nm. 5. The image forming method according to claim 1, wherein the perylene pigment is a mixture of the compounds represented by the general formula [1] and the general formula [2]. .