JP2819432B2 - Electrophotographic photoreceptor, electrophotographic apparatus provided with the electrophotographic photoreceptor, and facsimile - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, an electrophotographic apparatus, and a facsimile, and more particularly, to an electrophotographic photosensitive member having a photosensitive layer containing a compound having a specific structure, and the electrophotographic photosensitive member. The present invention relates to an electrophotographic apparatus provided with a photoreceptor and a facsimile.

[Prior Art] In recent years, many electrophotographic photosensitive members using an organic compound as a photoconductor have been developed. Most of the practically used ones have a form in which a photoconductor is functionally separated into a charge generating material and a charge transporting material. Electrophotographic photoreceptors using such organic photoconductors are expected to further improve electrophotographic characteristics such as sensitivity and photoresponsiveness due to flexibility in material design, and to facilitate film formation and production. It is characterized by high performance.

By the way, an electrophotographic photosensitive member repeatedly undergoes various image forming processes in an electrophotographic apparatus, and during that time, the electrophotographic photosensitive member is required to exhibit stable characteristics. However, the electrophotographic photoreceptor using the organic photoconductor as described above is liable to cause image deterioration such as image density unevenness due to a decrease in charging ability and image bleeding due to a decrease in surface resistance in repeated use. Has disadvantages.

One of the causes of such deterioration is considered to be the influence of corona discharge. Organic That is, when the electrophotographic photoreceptor is used in the copying machine, constantly are exposed to a corona discharge atmosphere, ozone generated by corona discharge according Repeated copying, NOx, the active species such as HNO ₃ It is believed that the photoconductor undergoes degradation. In particular, electrophotographic photoreceptors using organic photoconductors are often used with negative charging, but in the case of negative corona charging, the amount of ozone generated is larger than positive charging, which also uses positive charging. This is one of the factors that are more susceptible to deterioration than other electrophotographic photosensitive members.

Conventionally, as a method for preventing the deterioration of the electrophotographic photosensitive member as described above, it has been proposed to add various antioxidants (JP-A-57-122444, JP-A-58-120260, JP-A-61-156131, JP-A-62-105151, etc.).

[Problems to be Solved by the Invention] An object of the present invention is to eliminate the above-mentioned disadvantages by adding a specific basic compound to a photosensitive layer of an electrophotographic photosensitive member, that is, to prevent deterioration, and An object of the present invention is to provide an electrophotographic photosensitive member having no adverse effect on electrophotographic characteristics, and to provide an electrophotographic device provided with the electrophotographic photosensitive member, and an electrophotographic device and a facsimile provided with the electrophotographic photosensitive member.

[Means for Solving the Problems and Action] The present invention relates to an electrophotographic photoreceptor having a photosensitive layer containing a conductive support and an organic photoconductor, wherein the photosensitive layer comprises all of the layers to which a compound represented by the following general formula is added. 0.05% by weight
It comprises an electrophotographic photosensitive member characterized by containing the above.

Where X is Is shown.

Further, the present invention comprises an electrophotographic photoreceptor in which the surface layer of the electrophotographic photoreceptor contains a lubricant powder selected from the group consisting of a fluororesin powder, a polyolefin-based powder and a carbon fluoride powder. You.

Further, the present invention comprises an electrophotographic apparatus provided with the electrophotographic photoreceptor of the present invention.

Further, the present invention comprises an electrophotographic apparatus provided with the electrophotographic photoreceptor of the present invention and a facsimile having a receiving means for receiving image information from a remote terminal.

In the electrophotographic photoreceptor of the present invention, the photosensitive layer containing an organic photoconductor is a single-layer type photoreceptor in which a charge-separated charge generating material and a charge transporting material are mixed, or a charge containing a charge generating material. It can take the form of a laminated photoreceptor in which a generating layer and a charge transport layer containing a charge transport material are laminated.

It is possible to use organic dyes such as pyrylium dyes, thiapyrylium dyes, phthalocyanine pigments, anthantrone pigments, perylene pigments, sivenzpyrene quinone pigments, pyranthrone pigments, azo pigments, indigo pigments, quinacridone pigments as charge generation materials. it can.

As the charge transport material, pyrazoline-based, hydrazone-based, stilbene-based, triphenylamine-based, benzidine-based, oxazole-based, indole-based, carbazole-based compounds, and the like can be used.

In the case of a single-layer type photoreceptor, the above-described charge generating material and charge transporting material are dispersed and dissolved in a solvent together with a suitable binder resin, and coated on a conductive support to form a photosensitive layer. .

On the other hand, in the case of a stacked type photoreceptor, (a) a charge generation layer and a charge transport layer are laminated in this order on a conductive support or (b) a charge transport layer and a charge generation layer are laminated in this order.

As a method of forming the charge generation layer in the case of (a), there is a method of dispersing and dissolving the above-described charge generation material together with a suitable binder resin in a solvent, and coating the resultant on a conductive support.
The charge transporting layer is formed by dispersing and dissolving the above-described charge transporting material together with a suitable binder resin in a solvent, and coating and laminating it on the charge generating layer.

In this case, it is preferable that the additive comprising the compound represented by the general formula used in the present invention is contained in the charge transport layer.

On the other hand, in the case of (b), both layers can be formed in the same manner as in the case of (a).

However, in this case, it is preferable to include a charge transport material also in the charge generation layer.

In the case of (b), it is preferable that the additive comprising the compound represented by the general formula used in the present invention is contained in the charge generation layer or in both the charge generation layer and the charge transport layer.

The additive used in the present invention is a basic compound having two pyridine rings represented by the above general formula.

Pyridine shows basicity, and can capture HNO ₃ , HNO _{2, and the} like generated by corona discharge and prevent deterioration of the photosensitive layer.

However, simply increasing the basicity (electron density) is not sufficient, and the value differs depending on the photosensitive material used and the intended function.

Therefore, in the present invention, the electron density on the pyridine ring can be changed by bonding two pyridine rings with a group in which electrons are polarized, and a suitable effect can be obtained, that is, NO
Selection can be made as required, such as capturing _X and avoiding adverse effects on electrophotographic characteristics.

The amount of addition is 0.05% or more, preferably 0.1%, based on the total weight of the added layer (charge generation layer, charge transport layer or both).
1% or more.

The upper limit varies depending on the compound used, but the sensitivity decreases,
There is no problem unless the electrophotographic characteristics such as the increase in the residual potential are reduced, but it is approximately 20% or less.

In the present invention, the photosensitive layer may further contain a lubricant powder in the surface layer to reduce abrasion.

The lubricant powder that can be used in the present invention is selected from a fluororesin powder, a polyolefin-based powder, a fluorocarbon powder and the like. Fluororesin powder is preferred from the viewpoint of lubricity and releasability.

Fluorinated resin powders include ethylene tetrafluoride resin, ethylene trifluoride chloride resin, ethylene tetrafluoride-propylene hexafluoride resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride, and copolymers thereof. For example, polyethylene, polypropylene and their copolymers can be used as the polyolefin-based powder, and the amount of the lubricant powder is 1 to 1 with respect to the binder.
100% by weight is suitable, and particularly preferably 1.5 to 30% by weight.

Further, a dispersing aid for uniformly dispersing the powder may be used.

These lubricant are wear resistance be used in combination with compounds represented by the general formula for use in the present invention, it is excellent in both resistance to NO _X, i.e., to provide high durability of the electrophotographic photosensitive member.

In the present invention, as the conductive support, a known support generally used for an electrophotographic photoreceptor, for example, a cylindrical or belt-like aluminum, iron, copper or metal-deposited plastic film can be used.

In the present invention, an intermediate layer such as an adhesive layer, a barrier layer, and a smooth layer can be provided between the conductive support and the photosensitive layer, if necessary.

Coating can be performed by a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a Meyer bar coating method, a blade coating method, a roller coating method, and a curtain coating method. Drying is preferably performed by touch drying at room temperature and then heating and drying. The heating and drying can be performed at 30 to 200 ° C. for 5 minutes to 2 hours in a still or blown state.

The electrophotographic photoreceptor of the present invention can be widely used as a photoreceptor in electrophotographic application fields such as a laser beam printer, an LED printer, an LCD printer, a CRT printer, and a facsimile, in addition to being used in a normal electrophotographic copying machine.

Next, an electrophotographic apparatus and a facsimile provided with the electrophotographic photosensitive member of the present invention will be described.

FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention.

In FIG. 1, reference numeral 1 denotes a drum-type photosensitive member as an image carrier, which is driven to rotate at a predetermined peripheral speed in the direction of an arrow around a shaft 1a. The photoreceptor 1 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by a charging means 2 during the rotation process, and then exposed at a light exposure section 3 by an image exposure means (not shown) at an exposure section 3.
(Slit exposure, laser beam scanning exposure, etc.).

As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor.

The electrostatic latent image is then developed with toner by a developing unit 4, and the developed toner image is transferred by a transfer unit 5 between a photosensitive unit 1 and a transfer unit 5 from a paper supply unit (not shown) in synchronization with the rotation of the photosensitive unit 1. It is sequentially transferred onto the surface of the transfer material P taken and fed.

The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing, and is printed out as a copy (copy) outside the machine.

The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the untransferred toner by the cleaning unit 6, subjected to a charge removal process by the pre-exposure unit 7, and used repeatedly for image formation.

As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used.

Also, the corona transfer means is generally widely used for the transfer device 5.

As an electrophotographic apparatus, a plurality of components such as the above-described photoreceptor, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is configured to be detachable from the apparatus body. May be. For example,
The photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be detachable using guide means such as rails of the apparatus body. At this time, the above-described device unit may be provided with a charging unit and / or a developing unit.

In the case where the electrophotographic apparatus is used as a copier or a printer, the light image exposure L is performed by reflecting or transmitting light from the original, or by reading the original and converting it into a signal. This is performed by driving an array or driving a liquid crystal shutter array.

When used as a facsimile printer, the light image exposure L is an exposure for printing received data.

FIG. 2 is a block diagram showing one example of this case.

The controller 10 controls the image reading unit 9 and the printer 18.

The whole of the controller 10 is controlled by the CPU 16.

The read data from the image reading unit is transmitted to the partner station through the transmission circuit 12. Data received from the partner station is sent to the printer 18 through the receiving circuit 11. Predetermined image data is stored in the image memory. The printer controller 17 controls the printer 18. 13 is a telephone.

An image received from the line 14 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 11, and then the CPU 16 performs signal processing of the image information and is sequentially stored in the image memory 15. . When at least one page of the image is stored in the memory 16, the image of the page is stored. The CPU 16 reads out one page of image information from the memory 15 and sends out one page of image information signaled to the printer controller 17.

When receiving the image information of one page from the CPU 16, the printer controller 17 controls the printer 18 to record the image information of the page.

Note that the CPU 16 is receiving the next page during recording by the printer 18.

 As described above, image reception and recording are performed.

[Example] Example 1 An aluminum cylinder having a diameter of 80 mm and a length of 360 mm was used as a conductive support, and a 5% methanol solution of polyamide (trade name: Amilan CM-8000, manufactured by Toray Industries, Inc.) was immersed in the cylinder. To form an undercoat layer having a thickness of 0.5 μm.

Next, 10 parts of a trisazo pigment having the following structural formula, Six parts (parts by weight, hereinafter the same) of polyvinyl butyral (trade name: SREC BL-S, manufactured by Sekisui Chemical Co., Ltd.) and 50 parts of cyclohexane were dispersed by a sand mill using glass beads.

To this dispersion, 100 parts of methyl ethyl ketone was added and applied on the undercoat layer to form a 0.2 μm thick charge generation layer.

Next, 10 parts of a stilbene compound of the following structural formula, 10 parts of polycarbonate (trade name: Panlite L-1250, manufactured by Teijin Chemicals Ltd.) was dissolved in 10 parts of dichloromethane 50 buoyobichlorobenzene to prepare a coating solution for a charge transport layer.

2,2'-dipyridylamine 0.02 parts, 0.3 parts, 0.6 parts and 1.8 parts (respectively 0.1%, 1.5%, 3.0% and 9.0% were added to the dried charge transport layer), and these were added to the charge generation layer. It was applied thereon to form a charge transport layer having a thickness of 18 μm.

The prepared electrophotographic photoreceptors were used as photoreceptors 1, 2, and 3, respectively.
And 4.

Further, as a comparative sample, the photoreceptor 5 to which dipyridylamine was not added and the addition amount was 5 parts (25
%) Was prepared.

These photoconductors 1 to 6 were installed in an electrophotographic copying machine, and their electrophotographic characteristics were evaluated.

First, the conditions of the latent image were set such that the dark portion potential (V _D ) and the bright portion potential (V _L ) of the electrophotographic photosensitive member were -600 V and -150 V, respectively. The image exposure amount at that time was obtained and used as the initial sensitivity.

Then, 5 thousand potential after the continuous copying were measured to determine the increase in the reduction rate and V _L of V _D and, then, leave the photoreceptor in the copier, the surface after 10 hours The potential was measured.

At this time, the portion of the photoreceptor positioned immediately below the corona charger during the standing was marked, and the difference (ΔV _D ) from the other portions was determined. The results are shown.

As is evident from the above results, the photoreceptor containing no additive showed a remarkable decrease in the dark area potential due to repeated electrophotographic processes. In addition, when the addition amount is too large, there is an adverse effect that the light portion potential is significantly increased.

On the other hand, a photoreceptor having an appropriate additive content has a small decrease in charging ability, and does not show any practical adverse effect.

Example 2 10 parts of a disazo pigment having the following structural formula as a charge generation material, The dispersion was carried out by a sand mill using 6 parts of polyvinyl butyral (trade name: SREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and cyclohexanone 50 glass beads. To this dispersion was added 100 parts of tetrahydrofuran, and the dispersion was coated on the same conductive support and undercoat layer as in Example 1 by 0.2 μm.
An m-thick charge generating layer was formed.

Next, 8 parts of a benzcarbazole compound represented by the following structural formula as a charge transporting material, Styrene-acrylic copolymer resin (trade name Estyrene MS-
200, Nippon Steel Chemical Co., Ltd.) 10 parts, di-2-pyridylthionocarbonate 0.5 parts A solution dissolved in 15 parts of dichloromethane and 45 parts of chlorobenzene was applied on the charge generation layer to form a charge transport layer having a thickness of 18 μm.

 The prepared electrophotographic photoreceptor is referred to as a photoreceptor 7.

On the other hand, for comparison, a sample to which di-2-pyridylthionocarbonate was not added was prepared.

The electrophotographic characteristics of these photosensitive members were evaluated in the same manner as in Example 1. The results are shown.

Example 3 Using a disazo pigment having the following structural formula as a charge generation material, 2,2'-dipyridyl ketone as an additive An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except for using. This is designated as photoreceptor 9.

On the other hand, a sample to which the above-mentioned additive was not added was prepared for comparison, and this was designated as photoconductor 10.

The electrophotographic characteristics of these photosensitive members were evaluated in the same manner as in Example 1. The results are shown.

Example 4 In addition to the charge transport material, additives, and polycarbonate used in Example 1, polytetrafluoroethylene powder and a dispersing aid (trade name: Aron GF300, manufactured by Toa Gosei Chemical Industry Co., Ltd.) were prepared.

First, 10 parts of polycarbonate, 10 parts of a stilbene compound and 0.1 part of a dispersing agent are dissolved in 10 parts of chlorobenzene and 50 parts of dichloromethane.

Next, 5 parts of polytetrafluoroethylene powder was added thereto and dispersed in a stainless steel ball mill for 4 hours. Two more
0.6 parts of 2'-dipyridylamine was added.

This solution was coated up to the charge generation layer in the same manner as in Example 1 to form a 19 μm thick charge transport layer.

 The created electrophotographic photosensitive member is designated as photosensitive member 11.

Example 5 An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that di-2-pyridylthionocarbonate was used as an additive.

Example 6 An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that 2,2'-dipyridyl ketone was used as an additive.

The same evaluation as in Example 1 was performed for the photoconductors 11 to 13. The results are shown.

Example 7 An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that polyethylene powder was used instead of polytetrafluoroethylene, and this was designated as photosensitive member 14.

An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that carbon fluoride powder was used instead of polytetrafluoroethylene, and this was designated as photosensitive member 15.

The same evaluation as in Example 1 was performed for the photoconductors 14 and 15. The results are shown.

As described above, even when the lubricant and the dispersing agent are added, the compound represented by the general formula of the present invention does not cause a decrease in electrophotographic properties.

Example 8 Using the photoreceptors 11 to 13, 5,000 copies were made in the evaluation of the electrophotographic characteristics described above, and then 45,000 copies were made. As a result, even after the endurance of 50,000 sheets, there was no decrease in image quality compared to the initial stage, and a stable, high-contrast and uniform image was obtained.

[Effects of the Invention] The electrophotographic photoreceptor of the present invention has extremely high potential stability in a corona discharge environment, and can always form a stable high-quality image.

The same effect can be obtained in an electrophotographic apparatus and a facsimile equipped with the electrophotographic photosensitive member.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus using a drum type photoreceptor of the present invention. Reference numeral 1 denotes a drum type photosensitive member (electrophotographic photosensitive member of the present invention) as an image carrier, 2 denotes a corona charging device, 3 denotes an exposure unit,
Is a developing means, 5 is a transferring means, 6 is a cleaning means, 7
Denotes a pre-exposure unit, 8 denotes an image fixing unit, L denotes a light image exposure, and P denotes a transfer material that has undergone image transfer. FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus as a printer. Reference numeral 9 denotes an image reading unit, 10 denotes a controller, 11 denotes a receiving circuit, 12 denotes a transmitting circuit, 13 denotes a telephone, 14 denotes a line, 15 denotes an image memory, 16 denotes a CPU, 17 denotes a printer controller, and 18 denotes a printer.

Claims (4)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer containing a conductive support and an organic photoconductor, wherein the photosensitive layer is 0.05% based on the total weight of a layer to which a compound represented by the following general formula is added.
% Of an electrophotographic photosensitive member. Where X is Is shown. 2. The electrophotographic apparatus according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains a lubricant powder selected from the group consisting of a fluororesin powder, a polyolefin powder and a carbon fluoride powder. Photoconductor. 3. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1. 4. A facsimile comprising an electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1 and a receiving means for receiving image information from a remote terminal.