JPH0224667A - Image forming device - Google Patents

Abstract

PURPOSE:To accomplish excellent transfer regardless of the degree of smoothness of recording paper by forming a toner layer on an elastic layer which is a cylindrical insulator having an elastic layer and transferring to the recording paper. CONSTITUTION:A photosensitive drum 5 is constituted by forming the elastic layer 22 made of conductive rubber and a photosensitive layer 23 on an aluminum tube 21 in order. Even if the degree of smoothness of the recording paper is low, even the recessed part of the recording paper can be pressed on the drum 5 by a transfer roller 4 and a toner image on the drum 5 can be faithfully transferred on the recording paper.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an electrophotographic recording device, an ionography magnetography device, etc., in which a toner image formed on a drum-shaped image bearing member is transferred to a recording medium such as recording paper. The present invention relates to a recording device for forming.

[Conventional technology]

In a conventional transfer type image forming apparatus, an image bearing member is constructed by forming a toner image bearing layer on a metal pipe-shaped blank tube. That is, in the case of electrophotography, a photosensitive layer is formed on an aluminum tube, in the case of ionography, a dielectric layer is provided, and in the case of magnetography, a thin magnetic metal film layer is provided.

[Problem to be solved by the invention]

The conventional apparatus described above has a problem in that its characteristics are affected by the smoothness of the recording paper during the transfer process, making it impossible to obtain high quality images.

An object of the present invention is to solve this problem and realize an image forming apparatus that can obtain high image quality without depending on the smoothness of recording paper.

[Means to solve the problem]

The image forming apparatus of the present invention is characterized in that the image carrier has a cylindrical shape having an elastic layer, and is configured such that a toner image is formed on the elastic layer and transferred onto a recording medium.

[Effect]

In the above (1ζ structure) of the present invention, the image carrier follows the irregularities of the surface of the recording medium during transfer due to its elasticity, so good transfer is performed regardless of the smoothness.

〔Example〕

Next, the present invention will be explained based on examples. FIG. 1 is a diagram showing the configuration of a printer showing an embodiment of the present invention. The figure shows an electrophotographic printer. In the figure, recording paper sent out from a paper feeder is conveyed to a transfer position by a timing roller 2 in synchronization with the rotation of a photosensitive drum 5. Around the photosensitive drum 5 are a charging device 7, an exposure device (in the case of the figure, a head using a liquid crystal shutter) 9, and a developing device 3.
, a transfer device 4, a cleaning device W6, and a static eliminator 8 are provided. The recording paper onto which the toner image has been transferred is sent to a stacker 11 via a fixing device 10.

As shown in FIG. 2, the photosensitive drum is constructed by providing an elastic layer 22 made of conductive rubber on an aluminum tube 21, and a photosensitive layer 23 on the elastic layer. In this embodiment, the photosensitive layer 23 is made of OPC, and CGL, CTL, and a protective layer are coated in this order from the conductive rubber layer side.

Next, the operation will be explained. In FIG. 1, static electricity removal and charging of the photosensitive drum 5, formation of a latent image on the photosensitive drum, development with toner, cleaning of the transferred toner remaining on the photosensitive drum, and fixing of the transferred toner image on the recording paper are performed using well-known electrophotography. Since this is a process, the explanation will be omitted. In the transfer process of transferring the toner image formed on the photosensitive drum 5, which is an image carrier, to a recording paper (not shown), which is a recording medium, the recording paper and the outer peripheral surface of the photosensitive drum 5 are brought into contact with each other, and the toner image is transferred from behind. Press with roller 4. The transfer roller 4 is a metal roller with a smooth outer peripheral surface, and has a potential difference between it and the photosensitive drum element tube such that an electrostatic force acts so that the charged toner is attracted toward the recording paper side (toward the transfer roller). provided. Since the photosensitive drum 5 has an elastic layer, it is pressed by the transfer roller 4 even when the smoothness of the recording paper is low, so that the toner image is transferred well. That is, since the toner also comes into contact with and is transferred to the recessed portions of the recording paper, the toner image on the photosensitive drum is faithfully transferred to the recording paper without any portions where the toner is not transferred to the recessed portions of the surface of the recording paper.

As described above, the photosensitive drum is constructed by laminating a conductive rubber layer and a photosensitive layer on a hollow aluminum cylinder.The photosensitive layer is made of an organic material and has sufficient elasticity, so that the outer periphery of the photosensitive drum has elasticity. In the case of this example, 0.0 mm was placed on an aluminum tube with a diameter of 30 mm.
It has a conductive rubber layer and a photoreceptor layer with a thickness of 5 mm and 20 μm, respectively.

FIG. 3 shows another embodiment of the invention. This figure shows only the photosensitive drum. In the photosensitive drum of this embodiment, a rubber layer 32 is provided as an elastic layer on a hollow aluminum cylinder 31, an aluminum vapor-deposited thin film layer 33 is provided on the rubber layer, and a photosensitive layer 34 is further laminated. During operation, a potential is applied to the aluminum vapor-deposited thin film layer 33, so that the aluminum vapor-deposited thin film layer 33 is exposed at the end of the drum. In this configuration, since the aluminum vapor-deposited thin film layer 33 is thin and the photosensitive layer 34 also has elasticity, the elasticity of the rubber layer 32 is not impaired and an elastic drum can be constructed.

In the explanation of this embodiment, the case where a dry toner is used is described, but it is equally effective in the case of a wet process using a liquid developer, and the elasticity of the photosensitive drum allows for smoothness of the surface of the recording paper to be transferred more than 1. It is clear that an image is obtained. In the dry type, depending on the development method, it is necessary to control the gap between the photosensitive drum and the developing sleeve of the developing device with high precision, but in the wet type, the gap is relatively large and the setting margin can be large, and the smoothness of the recording paper is transferred. This configuration is particularly effective in a wet type because the characteristics tend to be highly dependent.

For image carriers for ionography and magnetography, which are generally formed by providing a dielectric layer and a magnetic layer on the outer periphery of a metal tube, a rubber layer can also be provided on the outside of the metal tube as in the previous embodiment. Furthermore, by providing a structure in which a dielectric layer and a magnetic layer are provided, the transfer characteristics can be improved in the same manner as described above.

In this embodiment, the charged toner is electrostatically attracted to the recording paper by pressing a voltage-applied roller to transfer it, but in the case of liquid toner or soft dry toner, transfer pressure alone is used to transfer the charged toner to the recording paper. Transfer can also occur without applying a voltage.

〔Effect of the invention〕

As described above, according to the above structure of the present invention, since the photoreceptor has elasticity, a good transferred image can be obtained without being affected by the surface roughness of the recording paper. Furthermore, due to the elasticity of the surface, the contact state of the cleaning mechanism is stable, and the surface of the drum can be kept clean without producing frictional noise.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a printer showing an embodiment of the present invention. FIG. 2 is a sectional view of a photosensitive drum used in a printer showing one embodiment of the present invention. FIG. 3 is a perspective view of a photosensitive drum showing another embodiment of the present invention. 5 Photosensitive drum 21.31 Aluminum tube 22.32 Elastic layer 2334 Photosensitive layer 33 Aluminum vapor deposited thin film layer and above Figure 2

Claims (1)

[Claims] In an image forming apparatus that transfers a toner image on an image carrier to a recording medium, the image carrier is cylindrical, the toner image is formed on the outer periphery of the cylindrical image carrier, and the transfer is performed by transferring the toner image between the recording medium and recording paper. An image forming apparatus characterized in that the image forming apparatus is formed by contacting and pressing the image carrier, and the image carrier has an elastic layer on the outer periphery.