JPH0534936A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body which can be lowered in noise and can provide higher image quality by sticking a lubricating material to the surface of a packing material and inserting this packing material into the electrophotographic sensitive body at the time of inserting the packing material to the photosensitive body. CONSTITUTION:A rubber roller 1d is formed by integrally molding a bar 1f made of aluminum and EPDM rubber 1e which is an elastic material. A silicone polymer 1c which is the lubricant is applied on the surface of the rubber roller 1d which is the packing material and thereafter, an aluminum cylinder 1b which is a conductive base body is press fitted to the inner side of a photosensitive drum supporting an org. photosensitive layer 1a. The packing material 1d is press fitted in the state of deforming the elastic body 1e on the surface layer by a pressure and moves while the surface of the packing material rubs against the inside wall of the photosensitive body and, therefore, the material having a high sliding property (lubricant) is made to exist between the inside wall of the photosensitive body and the surface of the packing material, by which the friction force, i.e. press fitting force can be decreased and stabilized without depending on the surface characteristics of the packing material.

Description

Detailed Description of the Invention

[0001]

The present invention relates to, for example, an electronic copying machine
The present invention relates to a method for manufacturing an electrophotographic photosensitive member used in an image forming apparatus such as an electrostatic recording device.

[Background Art] An image forming apparatus such as an electronic copying machine and an electrostatic recording apparatus includes a step of uniformly charging an object to be charged. A corona charging method is generally adopted as the charging processing means, but the corona charging method often requires generation of corona products such as ozone and requires additional means / mechanisms for coping with the corona charging method. It has problems such as high cost.

Therefore, recently, a contact charging method in which a charging member is brought into contact with a member to be charged for charging has been studied, and some of them have been put to practical use. In the contact charging method, a charging member to which a voltage (for example, a DC voltage of about 1 to 2 KV or a superimposed voltage of a DC voltage and an AC voltage) is applied is brought into contact with an object to be charged with a predetermined pressing force, and the object to be charged is predetermined. To be charged by forming an AC voltage having a peak-to-peak voltage that is at least twice the charging start voltage when a DC voltage is applied to the charging member, between the charging member and the member to be charged. Since the charging of the body can be made uniform, and the generation of ozone is greatly reduced as compared with the corona charging method, the corona charging method has an advantage that no additional means or mechanism indispensable is required.

[0004]

However, the contact charging device as described above is used as a charging unit of an image forming apparatus for forming an electrostatic latent image on a photosensitive member, which is a member to be charged, by line scanning, for example, a laser beam printer. If adopted, there are the following problems. When an image pattern is produced by repeatedly irradiating and non-irradiating a high-density laser with high density in the sub-scanning direction, when the frequency of the AC voltage applied to the contact charging member becomes close to the spatial frequency of the image pattern, moire fringes appear on the image surface. May occur. This can be solved by increasing the frequency of the AC voltage sufficiently, but when the contact charging member and the photoconductor are in contact with each other, the oscillating electric field formed between them causes vibration noise. It tends to occur. As one of the means for solving the problem, there is a method of inserting a filler into the inside of the photoconductor to make the photoconductor heavy. In this method, an elastic body is used as at least the surface layer of the filling material, and the filling material having an outer diameter set slightly larger than the inner diameter of the photoconductor is pressure-inserted (hereinafter, press-fitting). And fix it inside the photoconductor. The difference between the inner diameter of the photoreceptor and the outer diameter of the filler (hereinafter referred to as press fitting margin) is generally set in the range of 0 to 1 mm in consideration of the type of elastic body, hardness, friction coefficient and the like.

However, this method has an advantage that a means for fixing the filler inside the photosensitive member, for example, an adhering step is not required, but in order to perform stable press-fitting, the press-fitting margin of the elastic body and the surface characteristics are required. Although it is necessary to suppress the variation, in order to suppress the variation in the press-fitting margin, it is unavoidable to perform surface polishing after molding the filler, and as a result, variations in the surface characteristics of the elastic body such as surface roughness and friction coefficient due to polishing are caused. Will occur. Moreover, in order to suppress the variation in the surface characteristics of the elastic body, it is possible to make it non-polished, but the variation in the outer diameter cannot be suppressed as much as polishing, and in any case, there is a large variation in the pressure required for press-fitting (hereinafter referred to as pressure input). And in some cases,
There is a problem in that the photoreceptor is deformed because a large pressure input is required.

[Object of the Invention] The present invention has been made in order to solve the above problems, and even if there are variations in the surface characteristics of the elastic body, there is little variation in the pressure input and a low pressure input is sufficient. Therefore, it is an object of the present invention to provide a method for manufacturing an electrophotographic photosensitive member that does not cause deformation of the photosensitive member, and thus can reduce noise and improve image quality.

[0007]

The above-mentioned problems can be solved by inserting a lubricant into the surface of the filler when inserting the filler inside the electrophotographic photosensitive member.

Specifically, the filling material is pressed into the surface layer with the elastic body deformed by the pressure, and moves while rubbing the inner wall of the photoreceptor and the surface of the filling material. By the presence of a material having a large property (hereinafter referred to as a lubricant), the frictional force, that is, the pressure input can be reduced and stabilized without depending on the surface characteristics of the filler.

Examples of lubricants include siloxane compounds and solid lubricants, and types of solid lubricants include P.
Examples thereof include fluorine compounds such as TFE, PFA and PVDF, and layered lattice structure substances such as graphite, boron nitride and molybdenum disulfide.

The embodiment will be described below, but the present invention is not limited to this embodiment.

[0011]

【Example】

(Example 1) Aluminum rod 1f having a diameter of 22 mm and EPDM rubber 1e as an elastic body (JIS A hardness of 50 °)
Is integrally molded to have an outer diameter of 28.66 mm and a length of 70 mm
When the rubber roller 1d was prepared and the surface roughness was measured, the ten-point average roughness Rz was 19 μm. The surface of the rubber roller 1d as the filler is coated with the silicone polymer 1c having an average particle diameter of 12 μm as the lubricant, and then the organic photosensitive layer 1a is formed on the aluminum cylinder 1b as the conductive substrate.
Was pressed into the inner side of the photosensitive drum 1 having an outer diameter of 30 mm and an inner diameter of 28.5 mm by using a tensile / compression tester.
The pressure input at that time was measured and found to be 50 kgf.
Further, when the straightness of the photosensitive drum 1 was measured, it was 20
was μm. After that, a gear flange is bonded to both ends in the longitudinal direction (direction perpendicular to the paper surface of FIG. 1), and LBP-A404 is attached.
It was attached to the position of the photosensitive drum used for (Canon page printer) and the initial image was confirmed. As a result, a good image was obtained.

Comparative Example 1 The same procedure as in Example 1 was carried out except that no silicone polymer was used. The surface roughness Rz was 19 μm, the pressure input was 150 kgf, and the straightness was 102 μm. As a result of confirmation, it was found that partial density unevenness occurred, which was a problem in practical use.

Example 2 Instead of an aluminum rod having a diameter of 22 mm and EPDM rubber (JIS A hardness of 50 °), a brass rod having a diameter of 10 mm and a CR rubber (J
ISA hardness 50 °) with an outer diameter of 28.72 mm, a length of 60 mm and a surface roughness Rz = 9 μm, and PVDF with an average particle size of 20 μm was used as a lubricant instead of the silicone polymer. Except for this, the same procedure as in Example 1 was performed. As a result, the pressure input was 71 kgf and the straightness was 38 μm, and a good image was obtained by checking the initial image.

(Example 3) The same as Example 1 except that 70 ° EPDM rubber was used instead of JIS A hardness of 50 ° and graphite having an average particle size of 3 μm was used instead of the silicone polymer. When I went, the surface roughness R
z = 13 μm, pressure input is 62 kgf, straightness is 30 μm
When the initial image was confirmed, a good image was obtained.

FIG. 2 is a structural diagram of an electrophotographic printer as an example of an image forming apparatus incorporating the photosensitive drum 1 and the charging roller 2 shown in FIG. 1 as described above.

Reference numeral 1 denotes a photosensitive material such as an electrophotographic photosensitive drum, OPC, amorphous Se, and amorphous Si, which is formed on a cylindrical or belt-shaped base made of aluminum or nickel. In this embodiment, it has a cylindrical shape. A uniform charging is performed on the photosensitive drum 1 by a charging roller 2 which is a charging member that contacts the drum 1. Next, the laser scanner 3 performs raster scanning and exposure based on the image signal. The laser scanner 3 scans the blinking of the semiconductor laser with a polygon scanner and irradiates the photosensitive drum with an optical system. As a result, an electrostatic latent image is formed on the photosensitive drum 1. The produced electrostatic latent image is developed by the developing device 4. For the development, jumping development, two-component development, FEED development, or the like is used. When recording, reversal development is used in combination, in which a laser is turned on and toner is attached to one of the latent images having a lower potential.

The developed toner image is transferred to a transfer material. The transfer material is stored in the cassette 5 and is fed one by one by the paper feed roller 6. When a print signal is sent from the host computer, paper is fed by the paper feed roller 6, and the toner image is transferred onto the transfer material by the transfer roller 8 by the timing roller 7 in synchronism with the image signal. The transfer roller 8 is an electrically conductive elastic body having a low hardness, and is electrostatically transferred by a bias electric field in a nip portion formed by the photosensitive drum 1 and the transfer roller 8.

The transfer material onto which the toner image has been transferred is fixed by the fixing device 9, sent out of the apparatus by the paper discharge roller 10, and discharged to the paper discharge tray 11. On the other hand, the untransferred toner is cleaned by the blade of the cleaner 12.

FIG. 3 is a side view of a process cartridge which can be attached to and detached from the image forming apparatus shown in FIG. 2. The process cartridge C is a photosensitive drum 1, a charging roller 2 as a charging member,
The developing device 4 and the cleaner 12 are supported. Further, the process cartridge C is provided with a shutter 14 for protecting the photosensitive drum 1. Here, the process cartridge C may include at least the photosensitive drum 1 which is an image carrier and the charging roller 2 which is a charging member.

An oscillating voltage in which a DC voltage and an AC voltage are superposed is applied between the photosensitive drum 1 and the charging roller 2 by a power source, and an oscillating electric field is formed between the photosensitive drum 1 and the charging roller 2. The charge on the surface of the electrophotographic photosensitive member converges to a voltage substantially equal to the DC voltage. As described in Japanese Patent Application Laid-Open No. 63-149668, the oscillating voltage has a peak-to-peak voltage that is at least twice as high as the charging start voltage when a DC voltage is applied to the charging member. By forming an oscillating electric field between the photosensitive drum 1 which is a charging body, the photosensitive drum 1 can be uniformly charged. In order to satisfy this, in this embodiment, the peak-to-peak voltage is 2 KV, the frequency is 500 Hz, and the DC voltage is -700V. A rectangular wave, a triangular wave, a sine wave, or the like can be used as the oscillating voltage. However, since the sine wave does not include a harmonic component, the sine wave is preferable because it produces the smallest charging sound under the same conditions. Further, the oscillating voltage may be a pulse waveform formed by turning on and off the DC power supply, and may be a waveform in which the voltage periodically changes with time.

In the above embodiment, the noise can be reduced by press-fitting the filler inside the photosensitive member.

As described above, by applying the lubricant to the surface of the filler and press-fitting it into the photosensitive member, it is possible to achieve high image quality and low noise because of low pressure input and small variations in the pressure input. Furthermore, it is possible to obtain a method for manufacturing an electrophotographic photosensitive member suitable for mass production.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a photosensitive member having a filler pressed therein manufactured according to the present invention.

FIG. 2 is a side view showing an embodiment of an image forming apparatus to which the photosensitive drum of the present invention is applied.

FIG. 3 is a side view showing an embodiment of a process cartridge to which the photosensitive drum of the present invention is applied.

[Explanation of symbols]

 1 Photoconductor Drum 1a Photosensitive Layer 1b Base 1c Lubricant 1d Filling 1e Elastic Body 1f Core Bar

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Matsuda Kenji Matsuda, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Hiroaki Miyake 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Manabu Takano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiro Goto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. A method for producing an electrophotographic photosensitive member, which comprises depositing a lubricant on the surface of a filler having an elastic body on at least the surface layer and inserting the lubricant inside the electrophotographic photosensitive member. 2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the lubricant is a siloxane compound. 3. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the lubricant is a solid lubricant. 4. The method for producing an electrophotographic photosensitive member according to claim 3, wherein the solid lubricant is a fluorine compound. 5. The method for producing an electrophotographic photosensitive member according to claim 3, wherein the solid lubricant is a layered lattice structure substance.