JPH0772641A - Image carrier and image forming device - Google Patents

Abstract

PURPOSE:To prevent image quality from being deteriorated even when the diameter of an image carrier is made small by constituting the image carrier of a cylindrical supporting body made of a rigid body provided with an electrical conductive surface and a photoreceptor layer formed on the electrical conductive surface of the supporting body. CONSTITUTION:The image carrier 1 is constituted of the cylindrical supporting body 2 made of the rigid body provided with the electrical conductive surf ace and the photoreceptor layer 3 formed on the electrical conductive surface of the supporting body 2. That means, since the supporting body 2 is cylindrically formed, the cross section thereof is solid. Besides, since it is constituted of the material made of the rigid body, it is hardly deformed by mechanical pressure from the outside and the initial shape thereof is held. Then, an image is formed on the circumference of the carrier 1 rotatably held by a printer main body by an electrostatic charger 9 by corona electric discharge, an exposure device 10 by an LED array, a contact type developing device 11, a transfer device 13 for electrostatically transferring a toner image formed on the carrier 1 by the developing device 11 on a recording medium 12 and a cleaning device 14 scraping toner on the carrier 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image carrier and an image forming apparatus.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus using an electrophotographic process, a uniformly charged photosensitive member is irradiated with a light image to form an electrostatic image, and then a toner image corresponding to the electrostatic image is formed. Is formed on the photoreceptor to form a visible image. An image holding member for an electrostatic image or a toner image formed of this photoconductor is usually composed of a drum-shaped conductive support and a photoconductor layer formed on the support.

The drum-shaped electroconductive support is generally formed by extruding one end of an electroconductive element pipe, and then forming it into a predetermined diameter through a drawing process, followed by a cutting process and a straightening process. After the process, the cutting process and the cleaning process, the outer peripheral rough cutting process, the end face processing process, the outer peripheral finishing process and the cleaning process are performed by a dedicated machine, and then the surface is further coated and the like.

In addition to the method for producing the conductive support, there is also a method in which a metal plate is pressed into a mold by pressure to form it into a drum shape by a drawing process and then the above post-processing process is performed. is there. (Hereinafter, referred to as a first conventional technique.) However, such a manufacturing method requires many working steps in manufacturing. Furthermore, since the conventional drum-shaped conductive support is open at both ends or one end, the mechanical strength in the circumferential direction is not sufficient, and the drum-shaped conductive support may be deformed in the post-processing step. Even when it is used as a carrier, the cleaning blade, the magnetic brush, or the developer carrier that is pressed and held rotates against the pressure contact force, so that there is a problem that it may be deformed by pressure.

In particular, as a developing device, a one-component toner is carried while being carried on a developer carrying member composed of a semi-conductive roller, and during the carrying, toner particles are charged to a predetermined polarity and charged respectively. When the toner particles are configured to adhere to the electrostatic latent image on the image carrier, the thickness of the toner on the developer carrier is made extremely thin to ideally charge the toner (ideally, It is desirable to form a toner layer having a thickness corresponding to one toner particle on the developer carrier.) It is necessary to form a thin toner layer on the developer carrier.

Therefore, when the toner particles are transferred to the electrostatic latent image of the image bearing member, in order to obtain a high quality visible image, the developer bearing member is placed in the area where the developer bearing member and the image bearing member face each other. It is necessary to directly press the photoconductor or to place the toner layer and the surface of the drum at a small distance. At this time, the distortion of the surface of the photoconductor, the variation of its outer diameter, the deformation, the eccentricity, or the like deteriorates the quality of the developed image.

On the other hand, as disclosed in, for example, Japanese Patent Publication No. 4-73592, an image carrier is composed of an axis and an elastically deformable elastic material layer which is supported by the axis and which is in a cylindrical state in a free state. There is a technique in which, on the outer periphery of the carrier, a surface portion to which an external force is applied is elastically deformed, which is effective in improving the one-component developing characteristics. (Hereinafter, it is referred to as a second conventional technique.) However, in the second conventional technique, elastic deformation of the image bearing member is caused in a transfer process of transferring a toner image to a recording medium such as a recording paper other than the developing process. Causes problems such as image blurring at the time of transfer, and insufficient cleaning blade pressing force in the cleaning process.
In addition, there are drawbacks in that the apparatus is complicated in manufacturing the image carrier and it is difficult to reduce the size.

[0008]

As described above, in the first prior art of the related art, since the drum-shaped conductive support is open at both ends or one end, the mechanical strength in the circumferential direction is increased. Is not sufficient and may be deformed in the post-processing step, and even when it is used as a photoconductor drum, it resists the pressure contact force of the cleaning blade, the magnetic brush, or the developer carrier that is held under pressure. Since it rotates, there is a problem that it may be deformed by pressure.

Further, since the metal drum thus formed does not have a bottom portion, in order to mount it on the image forming apparatus as an image holding member, a flange as a joining member therefor is separately molded and integrated with the metal drum. It was necessary to attach it to the machine and required many working steps in manufacturing.

In the second prior art, elastic deformation of the image carrier causes image blurring during transfer in a transfer process other than the developing process, such as a transfer process for transferring a toner latent image onto a recording medium such as recording paper. Further, in the cleaning process, there is a problem that the pressure contact force of the cleaning blade is insufficient and cleaning failure occurs. In addition, there are drawbacks in that the apparatus is complicated in manufacturing the image carrier and it is difficult to reduce the size.

The present invention has been made to solve the above problems.

[0012]

The image carrier according to the present invention comprises a rigid support having a cylindrical and conductive surface, and a photosensitive layer formed on the conductive surface of the support.

Further, the image forming apparatus according to the present invention comprises an image carrier composed of a rigid support having a cylindrical and conductive surface, and a photoreceptor layer formed on the conductive surface of the support.
The image carrier includes a developing unit that develops the electrostatic latent image formed on the photoreceptor layer into a visible image, and a transfer unit that transfers the visible image obtained by the developing unit to a sheet. .

[0014]

As described above, the support for supporting the photosensitive layer is formed of a rigid body having a cylindrical shape and a conductive surface, so that the mechanical strength in the circumferential direction as an image carrier is dramatically improved. Even if the cleaning blade, the magnetic brush, or the developer carrier that is pressed and held is rotated against the pressure contact force, the deformation due to the pressure does not occur.

Further, in the image forming apparatus using such an image bearing member, the image bearing member can be prevented from being deformed even if the image bearing member has a small diameter, so that the image forming apparatus itself can be downsized. .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image carrier according to the present invention and an embodiment of an image forming apparatus incorporating the image carrier will be specifically described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of an image carrier according to the present invention, FIG. 2 is an axial sectional view of the image carrier shown in FIG. 1, and FIG. 3 is an image carrier shown in FIG. It is a schematic sectional drawing which shows an example of the attachment structure of. FIG. 4 is a cross-sectional view showing the overall configuration when an electrophotographic LED printer is constructed using the image carrier shown in FIGS.

First, the image carrier will be described with reference to FIGS. The image carrier 1 includes a rigid support 2 having a cylindrical conductive surface, and a photoreceptor layer 3 formed on the conductive surface of the support 2. That is,
Since the support body 2 has a columnar shape, the support body 2 has a solid cross section and is made of a rigid material, so that the support body 2 is not easily deformed by a mechanical pressure from the outside. Retain the initial shape. In particular, as compared with the conventional cylindrical support, the mechanical strength in the circumferential direction is dramatically improved, so that it is not necessary to consider such circumferential deformation when the diameter is reduced.

A rigid support 2 having such a conductive surface
The same material as that generally used as a conventional cylindrical support, for example, aluminum, iron, nickel, stainless steel or the like can be used as the material.

In order to form the shafts 4 and 4 having small diameters integrally on both end faces of the support 2, the surface of the metal material cut into a cylindrical shape by the cutting method is polished to a mirror-like surface finish. After the end face processing, one end of the roller is provided with a D cut 5 which is generally used as a rotation driving means. The method for producing the support 2 can be used as it is for the method for producing a metal shaft used as various industrial rollers in the related art, and the surface processing depending on the characteristics of the photoreceptor layer 3 as an image holding layer can be performed. A special processing step is not required for the support 2 of the image carrier 1 except when necessary.

On the support 2 formed as described above, a photoconductive photoreceptor layer 3 is formed in layers as an image holding layer. In this embodiment, a functional separation type organic photoconductor (hereinafter referred to as OPC) of a function separation type in which a charge generation layer and a charge transport layer are separated and laminated as the photoconductor layer 3 is sequentially laminated by a dipping method. Filmed In this embodiment, the laminated type negative charging type OPC was used as the photosensitive layer 3, but a single layer type OPC having a laminated function in a single layer, an amorphous silicon type photosensitive body, Se.
A system photoconductor may be used.

When an LED printer as an image forming apparatus is constructed using the image carrier 1 configured as shown in FIG. 1, the support 2 of the image carrier 1 is the image carrier 1 of the printer apparatus main body. Directly supported by the bearing. FIG. 3 shows such a bearing structure. The image carrier 1 and the bearings 6, 6 of the printer main body, and the drive gear 7 as a rotation driving means of the image carrier 1 are provided at both ends in the axial direction of the image carrier 1. Integral shaft 4, 4 or D
Each is attached to cut 5.

Therefore, the image carrier 1 according to the present invention does not require a separate flange to be joined as in the case of using a cylindrical drum as a conventional support, and the image carrier 1 is formed in a shaft shape. Therefore, the center of the rotation support shaft provided in the printer body is the roller rotation shaft of the image carrier. As a result, according to such a configuration, it is possible to easily determine the rotation axis that does not cause eccentricity, and it is possible to easily secure high whirling accuracy when rotated.

Next, a case where an LED printer is constructed by using the image carrier 1 of the present invention will be described with reference to FIG.

The LED printer shown in FIG. 4 is of the electrophotographic type, and its components and functions will be described. A charging device 9 by corona discharge, an exposure device 10 by an LED array, and a contact type developing device 11 which will be described later in detail, around an image carrier 1 rotatably held in the printer body.
A transfer device 13 for electrostatically transferring a toner image formed on the image carrier 1 by the developing device 11 to a recording medium 12 such as a recording paper, and a cleaning device 14 for scraping off the toner remaining on the image carrier 1. The series of image forming steps is repeated by.

The photoconductor layer 3 of the image carrier 1 is uniformly charged to a predetermined polarity by the charger 9, and then imagewise exposed by the exposure device 10. By the exposure, an electrostatic latent image is formed on the image carrier 1.

The developing device 11 carries a one-component toner while carrying the one-component toner on a developer carrying member 15 composed of a semi-conductive elastic roller, and during the carrying, the toner particles are charged to a predetermined polarity, respectively. It is configured to attach the charged toner particles to the electrostatic latent image on the image carrier 1. For the purpose of uniformly charging the toner, it is possible to make the thickness of the toner on the developer carrier 15 extremely thin, and ideally to form a toner layer having a thickness of one toner particle on the developer carrier 15. desirable. On the other hand, in order to form a thin toner layer on the developer carrying member 15 and transfer the toner particles to the electrostatic latent image on the image carrying member 1 to obtain a high quality visible image, Image carrier 1
The developer carrying member 15 is directly connected to the image carrying member 1 in the area facing each other.
To press. At this time, the contact state between the developer bearing member 15 and the image bearing member 1 needs to be precisely controlled, but according to the present invention, the surface of the image bearing member 1 is distorted, or its outer diameter varies or is deformed or eccentric. As a result, the occurrence of
Image quality deterioration due to such distortion and deformation of the image carrier 1 does not occur.

The toner image formed on the image carrier 1 by the developing device 11 is transferred onto the recording medium 12 by the transfer device 13, and then transferred onto the recording medium 12 by the fixing device 16 of the heating and pressure fixing system. It is fixed.

When the image carrier 1 having such a rigid structure is incorporated into an LED printer, the diameter of the image carrier 1 can be reduced without being restricted by mechanical strength. For example, in the case of the conventional cylindrical drum type image bearing member, when the one-component contact developing method, which is important for realizing personalization and maintenance-free operation, is used, its diameter needs to be 30 mm or more due to the above restrictions. there were. However, the image carrier 1 having a rigid body structure does not have the limitation, and further miniaturization can be realized in combination with the miniaturization of the LED array. As an example, the height is 50 mm or less,
It becomes possible to create a printer with a length (width) in the paper transport direction of 150 mm or less, and carry it by itself, integrate it with a portable personal computer, or store it compactly in a bookcase or desk drawer. You can

[0030]

As described above, the image carrier according to the present invention is remarkably improved in the mechanical strength in the circumferential direction as the image carrier, and is a cleaning blade, a magnetic brush, or a developer which is held by pressure. Even if the carrier or the like is rotated against the pressure contact force, deformation due to the pressure does not occur, so that it is possible to prevent deterioration of image quality even if the diameter is reduced.

Further, in manufacturing, not only can the surface accuracy of the support be improved relatively easily, but also due to the improved mechanical strength, the surface accuracy can be maintained for a long time even when used as an image forming apparatus. It is possible to maintain.

Further, the image bearing member of the present invention has its own rotation supporting function and the drive transmitting means can be formed coaxially, so that eccentricity of the image bearing member is extremely unlikely to occur.

In the image forming apparatus using such an image bearing member, the image bearing member can be prevented from being deformed even if the image bearing member has a small diameter, so that the image forming apparatus itself can be miniaturized. .

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an image carrier according to the present invention.

FIG. 2 is an axial sectional view of the image carrier according to the present invention shown in FIG.

FIG. 3 is a cross-sectional view showing a built-in structure of the image carrier according to the present invention shown in FIG.

FIG. 4 is a cross-sectional view of an LED printer that is an example of an image forming apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Support body, 3 ... Photosensitive material layer, 4 ... Shaft, 5 ... D cut, 6 ... Bearing, 7 ... Drive gear, 10 ... exposure device, 11 ... developing device, 13 ... transfer device, 14 ... cleaning device, 15 ... developer carrier, 16 ... fixing device.

Claims (2)

[Claims] 1. An image carrier comprising a rigid support having a cylindrical and conductive surface, and a photoreceptor layer formed on the conductive surface of the support. 2. An image carrier comprising a rigid support having a cylindrical and conductive surface and a photoreceptor layer formed on the conductive surface of the support, and formed on the photoreceptor layer of the image carrier. An image forming apparatus comprising: a developing unit that develops the electrostatic latent image into a visible image; and a transfer unit that transfers the visible image obtained by the development of the developing unit onto a sheet.