JP2003195577A - Electrophotographic device and electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic device capable of outputting a high-quality image excellent in resolution and gradation and free from a sweeping on the image at a high speed, and an electrophotographic photoreceptor used for the electrophotographic device. <P>SOLUTION: This electrophotographic device having the electrophotographic photoreceptor satisfying specified potential characteristic, an electrifying means satisfying specified potential by electrification, an exposure means for forming a digital latent image and a developing means performing contact development and satisfying specified developing contrast potential, and the electrophotographic photoreceptor for the electrophotographic device are provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member satisfying a specific potential characteristic, a charging unit satisfying a specific charging potential, and a digital latent image. The present invention relates to an electrophotographic apparatus having an exposing unit to be formed and a developing unit that performs contact development to satisfy a specific development contrast potential, and an electrophotographic photosensitive member for the electrophotographic apparatus.

[0002]

2. Description of the Related Art Generally, in electrophotography, an electrostatic latent image is formed by exposing an electrophotographic photosensitive member uniformly charged by a charging means to a portion required for printing. Is developed with toner, the toner image is transferred from the electrophotographic photosensitive member to a transfer paper, and the toner image on the transfer paper is fixed to form an image.

The developing system is a system in which the polarity of the charged potential (dark area charge) of the electrophotographic photosensitive member and the polarity of the toner are the same and a toner image is formed at the exposed portion (reversal developing system).
And a method in which a toner image is formed on an unexposed portion (regular development method), the polarities of which are different from each other. In recent years, semiconductor lasers and L have been used as exposure light sources.
A digital electrophotographic apparatus using an ED is the mainstream, and most of them employ a reversal development method.

Regarding the difference in the method of carrying the toner on the toner carrier, a two-component magnetic developing system using a mixture of toner and a magnetic carrier, only a magnetic or non-magnetic toner without using a magnetic carrier is used. The one-component developing method used and the like are known. Among these, the one-component system is excellent in terms of developer cost, developing device cost, and easiness of operation.

In the one-component developing system, a thin layer of charged toner formed on a developing roller composed of a conductive elastic roller is directly attached to the surface of an electrophotographic photosensitive member having an electrostatic latent image. There is a method of contacting to form a toner image,
This is also called a contact development system. For example, Japan H
ardcopy '89, pp. 25-28, FUJI
TSU Sci. Tech. , 28, 4, pp. 47
3-480 (December 1992), JP-A-5-
Techniques relating to one-component contact development are described in Japanese Patent No. 188756 and Japanese Patent Application Laid-Open No. 5-188752.

In the one-component contact development system, a constant bias voltage (developing bias voltage (V
_dc )) is applied. The polarity of the developing bias voltage is the same as the polarity of the charging potential (V _d ) of the electrophotographic photosensitive member,
_Letting V ₁ (V) be the light portion potential when the electrophotographic photosensitive member charged to _d (V) is entirely exposed, 0 ≦ | V ₁ | <|
There is a relationship of V _dc | <| V _d | (V).

[0007] The size of the _{V dc} is necessary development contrast potential to obtain the desired image density _(| V dc _-V l |)
And the back contrast potential (| V _d −V _dc |) required to prevent fogging is set to be maintained in an appropriate range determined by the relationship with the toner charge amount.

In the contact developing system, the toner carrier is pressed against the electrophotographic photosensitive member, so that a developed image having no edge effect can be obtained.

On the other hand, however, as a problem peculiar to the contact developing system, there is a phenomenon (sweeping) in which toner is swept up to the trailing edge of a solid image in the paper transport direction to form an unnecessary high density area. is there.

The direct cause of sweeping is not always the same, and a combination of many factors involved in the electrophotographic process, such as a change in temperature and humidity and a change in the characteristics of each member due to durability, causes the developability. It is believed that the change in the swelling will result in a sweep. However, when the sweeping is occurring, the development contrast potential is excessively large with respect to the toner development amount, except for the area where the toner is swept up.

Therefore, sweeping is eliminated by reducing the development contrast potential within a range in which the required development density can be secured and image defects such as fog do not occur. More specifically, by lowering the charging voltage in a range where image defects such as fog do not occur, and lowering the developing bias in a range in which a required developing density can be secured, the sweeping is improved by reducing the developing contrast potential. be able to.

As another means for eliminating the sweeping, there is also a method of increasing the peripheral speed of the developing roller relative to the peripheral speed of the electrophotographic photosensitive member so as to increase the toner supply amount and always maintain a high developing property. However, this is a trade-off with the harmful effects such as increasing the amount of abrasion of the electrophotographic photosensitive member to shorten the life and promoting deterioration of the toner, so the former is easier measure You can say that.

[0013]

However, an electrostatic latent image (referred to as a digital latent image) in which dot-shaped latent images are distributed corresponding to an image is formed by scanning with a laser beam or exposure using an LED array. In the so-called digital electrophotographic apparatus for forming, if the development contrast potential is lowered so that sweeping does not occur, it becomes difficult to faithfully develop each dot forming a digital latent image, and the resolution and Gradation tends to deteriorate, and there is room for further improvement in this respect.

In recent years, demands for higher image quality and full color have been further increased. However, it is not preferable that these adverse effects occur in a full color electrophotographic apparatus because it makes it difficult to reproduce colors faithfully.

Further, since there is a growing need for high-speed image output, it is strongly desired to develop a high-speed electrophotographic apparatus which does not cause the above-mentioned problems.

Therefore, the present invention provides a digital electrophotographic apparatus excellent in resolution and gradation, capable of outputting a high-quality image without sweeping at high speed, and an electrophotographic photosensitive member used in the electrophotographic apparatus. The purpose is to do.

[0017]

SUMMARY OF THE INVENTION That is, the present invention provides
Electrophotographic photosensitive member having photosensitive layer on carrier, charging means, dew
An electrophotographic apparatus having a light means and a developing means,
The charging means sets the charging potential of the electrophotographic photosensitive member to V_dTosu
Then, | V_d| ≦ 600V, which is a charging means,
Exposure means forms a digital latent image on the electrophotographic photoreceptor
Exposure means, and the developing means is provided on the toner carrier.
The toner layer formed by the carried toner is transferred to the electronic copy.
Contact the true photoconductor to develop the electrostatic latent image and
Trust potential V _contIs between 180V and 240V
In the electrophotographic apparatus as a developing means, the electrophotographic photosensitive
Body is | V_d| = 600 V Table of the electrophotographic photosensitive member
The exposure amount that attenuates the surface potential by 500 V is E_Δ500Tosu
Then, 0.35 μJ / cm^Two≤ E _Δ500≤0.6 μJ
/ Cm^TwoSatisfies | V_d| = 600V
The exposure amount that attenuates the surface potential of the true photoconductor by 300 V is E
_Δ300Then, E_{Δ5 00}/ E_Δ300≤2.5
An electrophotographic apparatus characterized by having the following potential characteristics:
is there.

Further, the present invention is an electrophotographic photosensitive member having a photosensitive layer on a support, and when the charging potential of the electrophotographic photosensitive member and the electrophotographic photosensitive member is V _d , | V _d | ≤6
A charging unit that satisfies 00V, an exposure unit that forms a digital latent image on the electrophotographic photosensitive member, and a toner layer formed by toner carried on a toner carrier are brought into contact with the electrophotographic photosensitive member and statically charged. An electrophotographic photosensitive member for an electrophotographic apparatus, which has a developing means for developing an electrostatic latent image and having a development contrast potential V _cont of 180 V or more and 240 V or less, wherein the surface of the electrophotographic photosensitive member is | V _d | = 600 V _Letting E _Δ500 be the exposure amount at which the electric potential is attenuated by 500 V, 0.35 μJ / cm ² ≦ E _Δ500 ≦ 0.6 μJ /
cm ² and | V _d | = 600 V, the exposure amount by which the surface potential of the electrophotographic photosensitive member is attenuated by 300 V is E.
_The electrophotographic photosensitive member is characterized in that it has potential characteristics such that E _Δ500 / E _Δ300 ≦ 2.5 when _Δ300 .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.

The developing means used in the electrophotographic apparatus of the present invention is a so-called contact developing type developing means.
As an example, there is a developing unit that employs a method in which a toner is coated on the surface of an elastic roller as a one-component developer and the toner is brought into contact with the surface of an electrophotographic photoreceptor. Regardless of whether the toner is magnetic or non-magnetic, it is important that the toner is in contact with the surface of the electrophotographic photosensitive member.

Further, the toner carrier is substantially in contact with the surface of the electrophotographic photosensitive member. This means that when the toner is removed from the toner carrier, the toner carrier contacts the electrophotographic photosensitive member. It means that

In order to develop the electrostatic latent image formed on the electrophotographic photosensitive member with the toner, between the surface of the elastic roller carrying the toner or the vicinity thereof and the electrostatic latent image on the electrophotographic photosensitive member. In addition, there must be sufficient electric field to move the toner. In order to maintain this electric field, the elastic rubber of the elastic roller is resistance-controlled in a medium resistance region to prevent electric conduction with the surface of the electrophotographic photosensitive member and to maintain the electric field, or a thin layer is formed on the surface layer of the conductive roller. A method of providing a dielectric layer or the like can be used.

Further, a conductive resin sleeve having a surface facing the surface of the electrophotographic photosensitive member coated with an insulating material on the conductive roller, or a conductive layer provided on the side of the insulating sleeve not facing the electrophotographic photosensitive member is provided. Different configurations are also possible.

When the one-component contact developing method is used, the developing roller carrying the toner is rotated so that the vectors of the peripheral velocities of the two parts at the point where the toner contacts the electrophotographic photosensitive member are in the same direction. It may be rotated in the opposite direction. When the rotations are in the same direction, the peripheral speed ratio with respect to the peripheral speed of the electrophotographic photosensitive member is preferably 100% or more, more preferably 120 to 300%, and further 140 to 250. % Is preferable. If it is less than 100%, there may be a problem in image quality such as line breakage. The higher the peripheral speed ratio, the larger the amount of toner supplied to the developing portion, the more frequently the toner is desorbed from the latent image, and the unnecessary portions are scraped off and attached to the necessary portions. By repeating, an image faithful to the latent image is obtained.

The present invention does not include a developing method using a developer containing at least a carrier and a toner, that is, a so-called two-component developing method.

In order to sufficiently prevent the sweeping without causing image defects such as fog, the charging potential V _d satisfies | V _d | ≦ 600 V and the development contrast potential (V _cont ). Is required to be 180 V or higher and 240 V or lower. If V _cont is less than 180 V, the developing density tends to be insufficient, and if V _cont exceeds 240 V, sweeping is likely to occur. On the other hand, | V _d | ≧ 300 V is preferable from the viewpoint of sufficient development density and prevention of background fog.

In the present invention, the developing contrast potential (V _cont ) is the developing bias applied to the toner carrying member, where V ₁ is the surface potential of the electrophotographic photosensitive member charged by the charging unit and exposed by the exposing unit. Voltage to V
_{With dc} , it can be derived as in the following formula.

V _cont = _{│V dc} -V _l │ Now, with respect to this development contrast potential, the present inventors faithfully reproduce each dot forming a digital latent image to obtain resolution and gradation. As a result of earnest studies for obtaining an excellent image, it was found that the object can be achieved by appropriately adjusting the shape of the light attenuation curve (EV curve) showing the light intensity dependence of the light attenuation of the electrophotographic photosensitive member. It was

In order to enable faster image output, the cycle of the electrophotographic process performed on the electrophotographic photosensitive member, that is, at least charging, exposure, development,
It is necessary to shorten the cycle in which a series of processes of transfer are performed, but if the light amount of the exposure light source is the same, the exposure amount per unit area of the electrophotographic photosensitive member is inversely proportional to the peripheral speed of the electrophotographic photosensitive member. Since the number of electrophotographic photoconductors is reduced, more sensitive electrophotographic photoconductors are required.

To meet these requirements, | V _d |
= 600 V, the surface potential of the electrophotographic photosensitive member is set to 500
If the exposure amount for V light attenuation is E _Δ500 , then 0.35
met _{^{μJ / cm 2 ≦ E Δ500 ≦}} 0.6μJ / cm 2, _and, | V d | = E _Δ30 the exposure amount of the surface potential of the electrophotographic photosensitive member was 600V attenuating 300V light ₀
Then, it is necessary that E _Δ500 / E _Δ300 ≦ 2.5.

Here, the charging potential is | V _d | = 600
V is only for defining the above characteristics, and it is not necessary that the charging potential V _d when actually used in the electrophotographic apparatus of the present invention satisfies | V _d | = 600 V.
_It suffices if _d | ≦ 600V is satisfied.

FIG. 1, FIG. 2 and FIG. 3 respectively show schematic diagrams of the light attenuation curve of the electrophotographic photosensitive member, the energy shape of one laser dot, and the potential shape of the latent image obtained thereby.

Considering the solid image portion, it is necessary to develop the toner amount necessary to obtain the image density.
Sufficient high sensitivity is required for the electrophotographic photoreceptor.

On the other hand, considering the halftone image portion, when the light amount is too low and the sensitivity is too high like the photoconductor B, the latent image becomes thick as shown in FIG. Becomes larger, the dots are crushed, the resolution is lowered, and it is difficult to obtain gradation. In particular, it is disadvantageous when the gradation is expressed by the pulse width modulation (PWM) method.

[0035] Thus, the electrophotographic photosensitive member used in the present invention, as the light amount region (the aforementioned ^{_{0~E Δ50 0 μJ / cm 2,}} E Δ500 is 0.35μJ / cm ²
It is 0.6 μJ / cm ² or less. ), In FIG.
The electrophotographic photosensitive member that exhibits the shape of the light attenuation curve (expressed as having high linearity) like the photosensitive member A is preferable to the photosensitive member B in 1. When the light attenuation curve becomes a straight line,
E _Δ500 / E _{Δ30 0} = _5/3 , which becomes larger than _{5/3 as} the linearity decreases.

On the other hand, it is necessary to increase the process speed in order to enable higher speed image output. In this case, if the sensitivity of the electrophotographic photosensitive member is low, the output of the exposure light source must be increased, but it is not preferable to use a high-luminance light source for that because the cost increases and the power consumption also increases. .

As described above, in the present invention, the above E
_Δ500 is 0.35 μJ / cm ² or more and 0.6 μJ / c
It is m ² or less.

If it is less than 0.35 μJ / cm ² , the linearity of the light attenuation curve is not sufficient, which is not preferable.

On the other hand, when it exceeds 0.6 μJ / cm ² , a high-speed electrophotographic process (especially, a cycle time of 1.
0 s / cycle or less).

The sensitivity of the organic electrophotographic photosensitive member largely changes depending on the selection of the charge generating substance, and by using a known high sensitive charge generating substance such as a phthalocyanine pigment, especially oxytitanium phthalocyanine and gallium phthalocyanine. , E _Δ500 ≦ 0.6 μJ / cm ² can be satisfied. However, as described above, in the electrophotographic apparatus of the present invention, it is necessary that the light attenuation in the low light amount region is not too large. Therefore, when using these extremely high-sensitivity charge generating substances, the amount and combination thereof are used. It is necessary to appropriately select the material (particularly the charge transport substance) or the construction method of the photosensitive layer so that desired light attenuation characteristics can be obtained.

By satisfying the above requirements, each dot forming a digital latent image without sweeping over the image is faithfully developed and a high quality image excellent in resolution and gradation is obtained. You can

The electrophotographic photosensitive member used in the electrophotographic apparatus of the present invention will be described in more detail below.

First, the support used in the electrophotographic photosensitive member may be any one as long as it has conductivity, such as aluminum, aluminum alloy,
Copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold and platinum can be used. In addition, plastics having a layer formed by vacuum deposition of aluminum, aluminum alloy, indium oxide, tin oxide, and indium oxide-tin oxide alloy (for example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin and Polyfluorinated ethylene), conductive particles (for example, particles of aluminum, titanium oxide, tin oxide, zinc oxide, carbon black, silver, etc.)
With a suitable binder resin (for example, phenol resin), a plastic or a support coated on the support, a support in which conductive particles are impregnated in plastic or paper, a plastic having a conductive polymer, etc. You can

An undercoat layer having a barrier function and an adhesive function may be provided between the support and the photosensitive layer. Examples of the material of the undercoat layer include polyvinyl alcohol, polyethylene oxide, ethyl cellulose, methyl cellulose, casein, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon and N-alkoxymethylated nylon, etc.), polyurethane, glue, aluminum oxide and Gelatin or the like is used. The film thickness is 0.
The thickness is preferably 1 to 10 μm, more preferably 0.5 to 5 μm.

The structure of the photosensitive layer of the electrophotographic photosensitive member is a single layer type containing a charge generating substance and a charge transporting substance in a single layer,
The charge-generating layer containing a charge-generating substance as a main component and the charge-transporting layer containing a charge-transporting substance as a main component can be broadly classified into two types: a laminated type. The multi-layer type electrophotographic photoconductor is also called a function-separated type electrophotographic photoconductor, and it is said that many requirements such as high sensitivity and high durability desired for the electrophotographic photoconductor can be achieved relatively easily as compared with the single layer type. It has merits and is the current mainstream. Here, the case of a laminated electrophotographic photosensitive member will be described first.

The charge generation layer contains the charge generation substance together with a binder resin in an amount of 0.2 to 4 times on a mass basis and a solvent.
A homogenizer, an ultrasonic wave, a ball mill, a vibrating ball mill, a sand mill, an attritor, a roll mill, or the like is used to thoroughly disperse, coat, and dry the film. The film thickness is preferably 5 μm or less, and 0.01 to 1
More preferably, it is μm.

Examples of the charge generating substance include pyrylium,
Examples include thiopyrylium dyes, phthalocyanine pigments, anthanthrone pigments, dibenzpyrenequinone pigments, pyratron pigments, azo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanines and quinocyanines.

In the present invention, since it is necessary to use an electrophotographic photosensitive member having a high sensitivity to some extent, the phthalocyanine pigment having a high sensitivity to the red laser light as described above is suitable. Among them, gallium phthalocyanine and oxytitanium phthalocyanine are preferable, and further, Bragg angle 2θ in CuKα characteristic X-ray diffraction
Oxytitanium phthalocyanine compound having a maximum peak at 24.0 ° ± 0.2 °, 27.2 ° ± 0.2 ° or a Bragg angle 2θ of 7.4 ° ± 0.2 in CuKα characteristic X-ray diffraction A hydroxygallium phthalocyanine compound having a maximum peak at °, 28.2 ° ± 0.2 ° is suitable.

Among them, particularly, the Bragg angle 2θ ± 0.2 ° of CuKα characteristic X-ray diffraction of 9.0 °, 1
CuKα, a crystalline form of oxytitanium phthalocyanine having strong peaks at 4.2 °, 23.9 °, and 27.1 °
Bragg angle 2θ ± 0.2 ° in characteristic X-ray diffraction 9.
5 °, 9.7 °, 11.7 °, 15.0 °, 23.5
Oxytitanium phthalocyanine in crystalline form having strong peaks at °, 24.1 ° and 27.3 °, CuKα characteristic X
Bragg angle 2θ ± 0.2 ° in line diffraction of 7.3 °,
Hydroxygallium phthalocyanine in crystalline form having strong peaks at 24.9 ° and 28.1 °, Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction of 7.5 °,
9.9 °, 16.3 °, 18.6 °, 25.1 °, 2
A crystalline form of hydroxygallium phthalocyanine having a strong peak at 8.3 ° is preferred.

Examples of the binder resin used in the charge generation layer include polyester, acrylic resin, polyvinylcarbazole, phenoxy resin, polycarbonate, polyvinyl butyral, polystyrene, polyvinyl acetate, polysulfone, polyarylate, polyvinylidene chloride, acrylonitrile copolymer. And resins such as polyvinylbenzal.

The charge transport layer is formed mainly by applying a coating material in which a charge transport material is dissolved in a solvent together with a binder resin in an amount of 0.5 to 3 times on a mass basis, and drying. In the electrophotographic apparatus of the present invention, the film thickness is preferably 9 to 18 μm.

The charging voltage V _d of the electrophotographic apparatus of the present invention is |
Since V _d | ≦ 600 V, the thickness of the charge transport layer is 18
When the thickness is less than or equal to μm, the electric field applied to the photosensitive layer is strengthened, and it is possible to suppress the accumulation of residual carriers that may cause ghost and the like.

On the other hand, in terms of practical use, image defects such as fogging may occur due to insufficient charging ability.
It is preferable that the thickness is at least μm.

As the charge transport material, various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds,
Examples thereof include thiazole compounds and triallylmethane compounds.

Examples of the binder resin used in the charge transport layer include polyester, acrylic resin, polyvinyl carbazole, phenoxy resin, polycarbonate, polyvinyl butyral, polystyrene, polyvinyl acetate, polysulfone, polyarylate, polyvinylidene chloride and acrylonitrile copolymer. And resins such as polyvinylbenzal.

On the other hand, the single-layer type electrophotographic photosensitive member is formed as a single layer by mixing the above-mentioned charge generating substance, charge transporting substance and binder resin in an appropriate ratio.

The electrophotographic photosensitive member used in the present invention may be used by providing a protective layer on the above-mentioned photosensitive layer, if necessary.

As a coating method for each of the above layers, a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method and a beam coating method can be used.

The charge generating substance, the charge transporting substance, and the binder resin used in each layer may be used alone or in combination of two or more kinds.

If desired, each layer may contain various additives such as a dispersant, an antioxidant, a UV inhibitor and a lubricant.

An image forming method of the electrophotographic apparatus according to the present invention will be described by taking the electrophotographic apparatus shown in FIG. 4 as an example.

First, a voltage is applied to the charging member 1 placed in contact with the electrophotographic photosensitive member 2 so that the electrophotographic photosensitive member 2 is exposed.
The surface is charged, and the image corresponding to the original is exposed on the electrophotographic photosensitive member 2 by the exposing means 4 to form an electrostatic latent image. Next, the toner in the developing device 5 is brought into direct contact with the electrophotographic photosensitive member 2 by the above-mentioned contact developing member 5a to develop (visualize) the electrostatic latent image on the electrophotographic photosensitive member 2. .
Further, the toner image formed on the electrophotographic photosensitive member 2 is transferred onto the supplied transfer material P such as paper by the transfer charger 6, and the cleaner 7 does not transfer the toner image to the transfer material P. The residual toner remaining on the top is collected. After that, the pre-exposure means 8 applies light to the electrophotographic photosensitive member 2 to remove electricity. The pre-exposure unit may be omitted. On the other hand, the transfer material on which the toner image is formed is a transport unit (not shown).
Is sent to the fixing device 9 to fix the toner image.

In this image forming apparatus, the light source of the exposing means 4 may be laser light or LED array. If necessary, other auxiliary processes may be added.

In the present invention, among the components such as the electrophotographic photoreceptor 2, the charging member 1, the developing device 5, the cleaner 7 and the pre-exposure means 8 described above, a plurality of components are integrally combined as a process cartridge. The process cartridge may be detachably attached to the main body of the electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the charging member 1, the developing device 5 and the cleaner is integrally supported together with the electrophotographic photosensitive member 2 to form a cartridge, which is attached to and detached from the apparatus body by using a guide means such as a rail (not shown) of the apparatus body. Possible process cartridges.

The electrophotographic apparatus of the present invention can be widely applied to electrophotographic application fields such as electrophotographic copying machines, laser beam printers, LED printers and laser plate making.

[0066]

EXAMPLES The present invention will be described below with reference to examples.

"%" And "parts" shown below mean "% by mass" and "parts by mass", respectively.

Example 1 50 parts of titanium oxide powder coated with tin oxide containing 10% antimony oxide, 25 parts of resol type phenolic resin, and methyl cellosolve 20.
Parts, 5 parts of methanol and 0.002 parts of silicone oil (polydimethylsiloxane / polyoxyalkylene copolymer, average molecular weight 3,000) are dispersed for 2 hours in a sand mill using 1 mmφ glass beads to prepare a conductive layer coating material. Prepared. A conductive layer coating material was applied onto an aluminum cylinder (φ30 mm, length 260.5 mm) by a dip coating method and dried at 140 ° C. for 30 minutes to form a conductive layer having a film thickness of 15 μm.

A solution prepared by dissolving 5 parts of 6-66-610-12 quaternary polyamide copolymer in a mixed solvent of 70 parts of methanol and 25 parts of butanol was applied on the conductive layer by a dip coating method and dried, An undercoat layer having a thickness of 0.7 μm was formed.

Next, the Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction is 7.5 °, 9.9 °, and 16.3.
2 parts of hydroxygallium phthalocyanine crystals having strong peaks at °, 18.6 °, 25.1 °, and 28.3 ° were combined with polyvinyl butyral resin (trade name: S-REC B
X-1, manufactured by Sekisui Chemical Co., Ltd.) 1 part by cyclohexanone 1
9 parts of a resin solution was mixed and dispersed for 3 hours in a sand mill using glass beads having a diameter of 1 mm to prepare a dispersion liquid, in which 69 parts of cyclohexanone and 13 parts of ethyl acetate were prepared.
Two parts were added and diluted to prepare a charge generation layer coating material.
The charge generation layer coating material is applied onto the undercoat layer by a dip coating method and dried at 100 ° C. for 10 minutes to give a film thickness of 0.12.
A charge generation layer of μm was formed.

FIG. 5 shows a powder X-ray diffraction pattern of the above hydroxygallium phthalocyanine crystal. The powder X-ray diffraction was measured using CuKα rays under the following conditions. Measuring instrument used: Mac Science Co., Ltd., full-automatic X-ray diffractometer MXP18 X-ray tube: Cu tube voltage: 50 kV tube current: 300 mA scanning method: 2θ / θ scanning scanning speed: 2 deg. / Min Sampling interval: 0.020 deg. Start angle (2θ): 5 deg. Stop angle (2θ): 40 deg. Divergence slit: 0.5 deg. Scattering slit: 0.5 deg. Receiving slit: 0.3 deg. Using curved monochromator Next, 8 parts of a charge transport material having a structure represented by the following structural formula,

[Outer 1]

Polyarylate resin having a repeating structural unit represented by the following structural formula (viscosity average molecular weight 100,0
00) 10 copies

[Outside 2]

Dissolved in 60 parts of chlorobenzene, a charge transport layer coating material was prepared. The charge transport layer coating material was applied onto the charge generation layer by a dip coating method and dried at 120 ° C. for 60 minutes to form a charge transport layer having a thickness of 11 μm. In this way, an electrophotographic photosensitive member was produced.

Next, the electrophotographic apparatus will be described. As an electrophotographic device, Hewlett-Packard LBP
"Laserjet 4000" (cycle time of electrophotographic process 1.0 s / cycle) was modified and used.

The outline of the apparatus will be described with reference to FIG.

This apparatus uniformly charges an electrophotographic photosensitive member (a drum shape having a diameter of 30 mm) 26 using a charging roller 21. After charging, an electrostatic latent image is formed by exposing the image portion with a laser beam, and a visible image (toner image) is formed with toner, and then the toner image is transferred onto a transfer material 28 by a transfer roller 27 to which a voltage is applied. To do.

The modification was performed as follows. First, the high voltage power supply substrate was modified so that the charging voltage and the developing bias voltage could be changed. The exposure device has a variable resistor,
The amount of laser light can be changed by adjusting the applied voltage. No pre-exposure means was provided in this apparatus.

Subsequently, the developing portion 22 of the process cartridge was modified as follows.

A medium resistance rubber roller made of urethane foam and having an electric resistance value of 10 ⁵ Ω · cm is used as the developing roller 24 in place of the aluminum sleeve containing the magnet serving as the toner supplier, and the nip of the photosensitive drum 26 is about 3 mm.
Abutted so as to be mm.

The rotational peripheral speed of the developing roller was in the same direction at the contact portion with the electrophotographic photosensitive member, and was driven so as to be 150% of the rotational peripheral speed of the electrophotographic photosensitive member. The peripheral speed of the developing roller was 141.3 mm / s, and the peripheral speed of the surface of the electrophotographic photosensitive member was 94.2 mm / s.

As a means for applying toner to the developing roller 24, an applying roller 25 is provided inside the developing container 22,
It was brought into contact with the developing roller 24. The toner was applied onto the developing roller 24 by rotating in the direction opposite to the developing roller 24 at the contact portion. Further, a stainless steel blade 23 coated with resin was attached for controlling the toner coating layer on the developing roller 24. As a cleaning member, the blade 2 in the cleaner container 30 is used.
9 was used.

As the toner, one manufactured by a polymerization method was used.

The measurement, sampling and image evaluation were performed as follows.

The light decay curve of the electrophotographic photosensitive member is as shown in FIG.
The test was carried out under the environment of 3 ° C. and 53% RH. The voltage applied to the charging member is adjusted so that the charging potential (V _d ) of the electrophotographic photosensitive member is −600 V, and then the exposure amount is 0.1 to 10.
For each time of changing in 0.1μJ / cm ² increments in the range of 0.7μJ / cm ^2, measured bright potential _{(V l)} obtained while the solid image output, the relationship between the exposure amount and the light potential It was determined by plotting on a graph. The values of V _d and V ₁ described above are measured values at the position of the developing device. The obtained light attenuation curve is shown in FIG.

From the graph, E _Δ500 = 0.48 μJ /
It was found that cm ² and E _Δ500 / E _Δ300 = 2.3.

Subsequently, the apparatus was moved to an environment of 32.5 ° C. and 85% RH, the exposure amount was adjusted to Vd = −600V and Vl = −80V, and the developing bias voltage (V _dc ) was set to −. Adjusted to 230V. Under this condition, a sweep-up evaluation image including an appropriate solid image portion, a full-screen solid image, a grid pattern image of 1 vertical and horizontal 1 dot 2 spaces (a grid pattern), a vertical 1 dot 2 space and horizontal 1 dot 3 space grid Output a pattern image (let's call it a lattice pattern), observe them visually and with a microscope,
Sweeping in the solid image area and changes in resolution and image density in the grid pattern were evaluated.

Image evaluation was performed according to the following criteria.

Sweep: A = none.

B = very small.

C = Poor, or other image defect occurred.

Resolution of lattice pattern: A = white portion between lattices can be clearly expressed as a lattice pattern.

B = The white part between the grids is not clear in the grid pattern, but can be expressed by.

C = The white part between the lattices is indistinct with the lattice pattern, or other image defects occur.

Density Change of Lattice Pattern: A = When the solid image and the lattice pattern are visually compared, the density changes of the three types of images can be clearly discriminated.

B = visually solid image, lattice pattern,
When compared with each other, only the lattice pattern looks clearly thin.

C = visually solid image, lattice pattern,
When comparing, the density difference between the three types of images is unclear, or other image defects occur.

The results are shown in Table 1.

Examples 2 to 9 and Comparative Examples 1 to 3 In the image evaluation of Example 1, the charging potential and the developing bias voltage at the time of image output were changed as shown in Table 1. Evaluation was performed in the same manner as 1. The results are shown in Table 1.

Example 10 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer in the electrophotographic photosensitive member prepared in Example 1 was changed to 18 μm. When the electrical characteristics were measured, E _Δ500 = 0.35
μJ / cm ² , E _Δ500 / E _Δ300 = 2.5. Then, the same evaluation as the image evaluation of Example 1 was performed. The results are shown in Table 1.

[Example 11] The electrophotographic photosensitive member prepared in Example 1 was changed to 5 parts except that the charge transport material was 5 parts.
An electrophotographic photosensitive member was produced in the same manner as in Example 1. When the electrical characteristics were measured, E _Δ500 = 0.59 μJ / c
m ² and E _Δ500 / E _Δ300 = 2.2. Then, the same evaluation as the image evaluation of Example 1 was performed. The results are shown in Table 1.

Example 12 In the electrophotographic photosensitive member prepared in Example 1, 1.8 parts of the hydroxygallium phthalocyanine used in Example 1 as the charge generating substance and the azo compound 0 having a structure represented by the following formula: .2 copies

[Outside 3]

Example 1 except that the thickness of the charge generation layer was 0.2 μm and the thickness of the charge transport layer was 9 μm.
An electrophotographic photosensitive member was produced in the same manner as. When the electrical characteristics were measured, E _Δ500 = 0.55 μJ / cm ² , E
_Δ500 / E _Δ300 = 1.96. Then, the same evaluation as the image evaluation of Example 1 was performed. The results are shown in Table 1.

[Comparative Example 4] In the electrophotographic photosensitive member prepared in Example 1, as a charge generating substance, a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction of 9.5 °,
9.7 °, 11.7 °, 15.0 °, 23.5 °, 2
Using 4 parts of crystalline oxytitanium phthalocyanine having strong peaks at 4.1 ° and 27.3 °, the charge generation layer has a thickness of 0.30 μm, and the charge transport layer has a thickness of 28 μm.
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that m was set. When the electrical characteristics were measured, E _Δ500 =
0.29 μJ / cm ² , E _Δ500 / E _Δ300 = 2.
It was 5. Then, the same evaluation as the image evaluation of Example 1 was performed. The results are shown in Table 1.

[Comparative Example 5] In the electrophotographic photosensitive member prepared in Example 1, 1.9 parts of hydroxygallium phthalocyanine used in Example 1 as a charge generating substance and an azo compound 0 having a structure represented by the following formula: 1st copy

[Outside 4]

In place of the charge-transporting substance used in Example 1, the charge-transporting substance 5 having a structure represented by the following formula is used.
Department

[Outside 5]

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the above was used. When the electrical characteristics were measured,
E _Δ500 = 0.72 μJ / cm ² , E _Δ500 / E
_Δ300 = 2.5. Then, the same evaluation as the image evaluation of Example 1 was performed. The results are shown in Table 1.

[0107]

[Table 1]

[0108]

According to the present invention, each dot forming a digital latent image can be faithfully developed and excellent in resolution and gradation, and a high quality image without sweeping can be output at high speed. An electrophotographic apparatus and an electrophotographic photosensitive member used in the electrophotographic apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical attenuation curve.

FIG. 2 is a schematic diagram of a light intensity distribution of one dot of a laser pulse.

FIG. 3 is a schematic view of the shape of one dot of a latent image.

FIG. 4 is an example of an electrophotographic apparatus of the present invention.

5 is a powder X-ray diffraction pattern of hydroxygallium phthalocyanine used in Example 1. FIG.

FIG. 6 is a schematic diagram of an electrophotographic apparatus used for measurement.

7 is a light decay curve of the electrophotographic photosensitive member of Example 1. FIG.

[Explanation of symbols]

1 Charging member 2 Electrophotographic photoreceptor 4 Exposure means 5 Developer 5a Contact development member P transfer material 6 Transfer charger 7 cleaner 8 Pre-exposure means 9 Fixing device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 502 G03G 15/08 507Z 507 (72) Inventor Nomichi Miki 3-30 Shimomaruko, Ota-ku, Tokyo No. 2 Canon Inc. (72) Inventor Hirotoshi Uesugi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Miyako Nagata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Incorporated (72) Inventor Yama ▲ saki ▼ To 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H027 DA02 DA04 EA01 EA02 EC06 EC09 EC11 ED03 ED06 ED09 2H068 AA29 FC01 FC05 FC08 2H076 AB02 AB12 AB16 AB42 AB54 DA21 2H077 AD06 AD13 AD17 BA03 EA13 EA14 EA15 FA13 FA22 GA17 2H200 FA16 FA18 GA23 GA33 GA34 GA46 GB02 GB12 GB22 HA03 HB12 HB22 HB48 NA02

Claims (6)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a support.
An electronic copy having a body, a charging means, an exposing means and a developing means.
True device, wherein the charging means is a belt of the electrophotographic photosensitive member.
The electric potential is V_dThen, | V_d│ Band that satisfies 600V
And an exposing means is provided on the electrophotographic photosensitive member.
An exposing means for forming a digital latent image, wherein the developing means is
The toner formed by the toner carried on the toner carrier is
Development of an electrostatic latent image by bringing a toner layer into contact with the electrophotographic photoreceptor.
And the development contrast potential V _contIs 180V or more
In the electrophotographic device which is the developing means of 240V or lower
And the electrophotographic photosensitive member is | V_d| = 600V
Exposure that attenuates the surface potential of the electrophotographic photosensitive member by 500 V light
Quantity E_Δ500Then, 0.35 μJ / cm^Two≤ E
_Δ500≦ 0.6 μJ / cm^TwoSatisfies | V_d| = 6
The surface potential of the electrophotographic photosensitive member set to 00 V is 300 V light.
Exposure amount to be attenuated is E_Δ300Then, E_{Δ5 00}/
E_Δ300Characterized by having a potential characteristic of ≦ 2.5
And an electrophotographic device. 2. The film thickness of the photosensitive layer is 9 μm or more and 18 μm or more.
The electrophotographic apparatus according to claim 1, wherein 3. The cycle time is 1.0 s / cycle.
The electrophotographic apparatus according to claim 1, wherein: 4. An electrophotographic photosensitive member having a photosensitive layer on a support, wherein | V _d | ≦ 600 V is satisfied, where V _d is a charging potential of the electrophotographic photosensitive member and the electrophotographic photosensitive member. An electrostatic latent image is formed by bringing a charging unit, an exposing unit that forms a digital latent image on the electrophotographic photosensitive member, and a toner layer formed of toner carried on a toner carrier into contact with the electrophotographic photosensitive member. And the development contrast potential V
_In the electrophotographic photosensitive member for an electrophotographic apparatus having a developing unit having a _cont of 180 V or more and 240 V or less, | V _d
| = 600 V, the surface potential of the electrophotographic photosensitive member is 50
If the exposure amount for 0 V light attenuation is E _Δ500 , then 0.3
Met _{^{5μJ / cm 2 ≦ E Δ500 ≦}} 0.6μJ / cm 2, | V d | = When the surface potential of the electrophotographic photosensitive member was 600V and E _Deruta300 exposure amount to attenuate 300V _light, E Δ500 / E _An electrophotographic photosensitive member having a potential characteristic of _Δ300 ≦ 2.5. 5. The film thickness of the photosensitive layer is 9 μm or more and 18 μm or more.
The electrophotographic photoreceptor according to claim 4, wherein 6. The electrophotographic photosensitive member according to claim 4, wherein the electrophotographic apparatus has a cycle time of 1.0 s / cycle or less.