JPH0295668A - Image forming device - Google Patents

Abstract

PURPOSE:To facilitate the separation of transfer sheets and suppress the generation of retransfer by disposing an elastic roller under the hardness of 50 degrees and a metallic roller so that every transfer sheet may be curled in such a direction that it is peeled from a photosensitive body. CONSTITUTION:A transfer sheet is clamped and conveyed by an elastic roller 3 made of an elastic material under 50 degrees in JIS spring type hardness and a metallic roller 4. As a result, the transfer sheet is delivered being curled downward and thereby in the state of easy separation from a photosensitive body 1, so that the electricity removal of transfer sheets by means of an electro- static charge eliminator 8 is not quite needed, and neither is easily generated the retransfer phenomenon that the developing powder transferred onto the transfer sheet is stuck on the photosensitive body 1 again.

Description

[Detailed Description of the Invention] [Industrial Application Field] In a registration roller that feeds paper to a photoreceptor in synchronization with an image on the photoreceptor, an elastic roller is used to curl the paper in the direction of peeling it from the photoreceptor. The present invention relates to an image forming apparatus including a metal roller.

[Prior Art] Conventionally, in order to reliably feed the transfer paper to the photoconductor, the image forming bag neck (1) has fed the transfer paper by sandwiching it between resist rollers that press a metal roller against an elastic roller. A hard elastic roller was used, and the arrangement of the elastic roller and metal roller was varied.

[The problem that the invention is trying to solve, however,
In the above conventional example, the hardness of the elastic roller of the registration roller is large, so the amount of curl at the leading edge of the transfer paper is small.
The vertical arrangement of the elastic roller and metal roller varies, so when the elastic roller is placed on the bottom side, the curl direction of the leading edge of the transfer paper is upward, and when the transfer paper is fed below the photoreceptor, The transfer paper sticks to the photoconductor, which is disadvantageous when separating the transfer paper from the photoconductor.

[Means for Solving the Problems (and Effects)] According to the invention, a JIS spring-type elastic roller made of an elastic material with a hardness of 50 degrees or less and a metal roller are used to transfer transfer paper with a certain nip width. The transfer paper is clamped and conveyed to ensure curling, and the elastic roller and metal roller are arranged so as to curl in the direction of peeling from the photoreceptor, which is advantageous when separating the transfer paper from the photoreceptor.

[Embodiment] FIG. 1 is a diagram showing the main configuration of an embodiment of the present invention. l
2 is a photoconductor, 2 is a developer that develops the latent image on the photoconductor, 3 is the upper roller of the registration roller (JIS spring type) made of an elastic material with a hardness of 50 degrees or less, and 4 is a metal with good surface lubricity. The lower rollers 5 and 6 of the registration rollers are paper guides, 7 is a transfer charger that transfers the image formed on the photoreceptor onto transfer paper, and 8 is a separation charger that separates the transfer paper stuck to the photoreceptor. A container 9 is a cleaner for cleaning the developer remaining on the photoreceptor after transfer.

The transfer paper sent out from the paper feed section (not shown) passes through the paper guide 5 and first hits the surface of the metal roller 4, and then moves between the metal roller 4 and the elastic roller 3 along the surface of the metal roller 4. sent between. Furthermore, when the transfer paper is fed, the transfer paper forms a loop in the paper guide 5, and hits the registration roller with pressure, and the registration is adjusted. Next, when the registration rollers 3 and 4 rotate, the transfer paper is placed. Since the transfer paper is nipped and conveyed with a nip width, the transfer paper is sent out with a downward curl due to the deformation of the elastic roller 3. The transfer paper sent to the photoreceptor 1 is charged by a transfer paper charger, and the developer on the photoreceptor 1 is transferred to the transfer paper. Next, the charge on the transfer paper is removed by the separation charger 8 and the transfer paper is separated from the photoconductor L. At this time, the transfer paper is curled downward by the registration roller, so it is in a state where it is easily separated from the photoconductor L. Since it is not necessary to remove the charge from the transfer paper using the separation charger 8, the developer transferred onto the transfer paper adheres to the photoreceptor l again. The so-called retransfer phenomenon is unlikely to occur. Next, the developer remaining on the photoreceptor 1 is cleaned by a cleaner 9.

In this example, the outer diameter of the metal roller is φ14 [m
It is desirable that it be less than s1.

[Other Embodiments] Figures 2 and 3 are diagrams showing other embodiments of the present invention in which a sponge material is used as the elastic roller. FIG. 3 is a sectional view of the registration roller when a metal roller is disposed on the side, and is a diagram showing the abutting positional relationship between the elastic roller and the metal roller.

23 is an elastic roller made of sponge material, 24 is a metal roller, and 25 is a gap between the elastic roller 23 and the metal roller 24.
This is an abutment roller that positions p.

When using a sponge material as the elastic roller, the amount of deformation of the sponge cannot be determined by the pressing pressure of the abutment, so in order to keep the amount of deformation of the sponge constant and the paper feeding speed constant, an abutment roller is installed on the shaft of the metal roller 24. 25 are fitted and fixed and abutted against the shaft of the elastic roller 23. This makes it possible to keep the amount of deformation of the sponge constant, give a constant curl to the transfer paper, and feed the transfer paper at a specified speed.

[Effects of the Invention] As explained above, by arranging the soft elastic roller and the metal roller of the registration roller so that the transfer paper curls in the direction in which it is peeled off from the photoreceptor, the transfer paper is removed from the photoreceptor. Separation is facilitated, and there is no need to remove electricity from the transfer paper using a separation charger during separation, which has the effect of suppressing the occurrence of retransfer.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the main structure of an embodiment of the present invention, Fig. 2 is a sectional view when sponge material is used as the elastic roller, and Fig. fJII3 is a diagram showing the elastic roller when sponge material is used as the elastic roller. The figure which shows the abutment state of a metal roller. 1 is a photoreceptor 3, an elastic roller 4, a metal roller 7, a transfer charger 8, a separation charger 23, an elastic roller 24 made of sponge material, and a metal roller 25, an abutting roller.

Claims (1)

[Claims] 1. In the registration roller that feeds the transfer paper to the photoconductor in synchronization with the image on the photoconductor, the transfer paper is curled so that it curls in the direction of peeling off from the photoconductor when the paper is fed to the photoconductor. An image forming apparatus characterized in that the registration roller has a JIS spring type elastic roller made of an elastic material having a hardness of 50 degrees or less and a metal roller.