JPH08335019A - Image forming apparatus - Google Patents

Abstract

PURPOSE: To discharge transfer paper sheets on a transportation line along the transportation line without bearing a toner and avoid using unused transfer paper sheets in vain by stopping image forming process partially in the case of the restoration after occurrence of jamming. CONSTITUTION: When image formation is carried out continuously, a plurality of transfer paper sheets exist simultaneously in a transportation line passing through a transfer paper sheet supplying position, a transferring position, and a fixing apparatus 7 and reaching a discharge tray 8. In this condition, at the time when jamming occurs at any position, a transfer paper sheet existing at the transferring position is made to move forward as it is and discharged out of an image forming apparatus after fixing process is carried out since a toner already adheres to a part of the sheet. Since transfer paper sheets behind the transfer paper sheet 62 are in unused state, the transfer bias of an electric charging apparatus 5 is turned off before those paper sheets reach the transferring position in order to avoid adhesion of a toner and the paper sheets are transported and discharged outside. Measures to turn off a primary charging bias by a control switch 22, to irradiate the whole surface of an image carrying body 1 with a blank exposure light 3, and to avoid adhesion of a toner to a development sleeve 4 by a control switch 42, may further be employed to improve the effect.

Description

Detailed Description of the Invention

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrostatic transfer process such as an electrostatic copying machine and a printer.

[0002]

In the known image forming apparatus as described above, a transfer material such as paper is conveyed and supplied to the position of the toner image formed on the image carrier to transfer the toner image to the transfer material. After the transfer, the transfer material carrying the toner image is further conveyed to the fixing portion to fix and fix the toner image on the transfer material, and then the transfer material is discharged out of the apparatus.

As described above, the transfer material is conveyed from the supply portion to the transfer portion and the fixing portion. On the other hand, the paper, which is often used as the transfer material, has its characteristics easily changed depending on the environment, especially humidity, so that the transfer material may be changed depending on handling. It is difficult to completely prevent the occurrence of a paper jam (jam) during the conveyance because the strength of the sheet changes and curls occur, which makes it difficult to smoothly convey the sheet.

For this reason, conventionally, in order to facilitate jam processing, an auxiliary mechanism is provided at an appropriate position of the conveyance path to facilitate removal of the transfer material jammed at that position.
It is well known that a method has been proposed in which the entire transfer path can be opened as needed to remove a jammed transfer material, and a certain effect has been achieved.

At the same time, however, the known device inevitably causes an increase in cost due to the jam clearance mechanism. Further, in any of the above means, it is customary that the operator of the apparatus removes all the transfer material existing in the conveyance path, including the transfer material clogged each time. In some cases, it may be necessary to remove the transfer material to which the toner has not been transferred and adhered. At that time, there is a problem in that the usable paper may be wrinkled and must be discarded.

The present invention has been made in view of such a situation as described above, and a part of the functions of the image forming process is stopped so that all the transfer materials in the conveying path can be removed without performing image formation on the transfer material. An object of the present invention is to provide an image forming apparatus that eliminates waste of transfer material by discharging the transfer material from the original discharge site to the outside of the machine.

[0007]

Configuration of the Invention

In order to achieve the above-mentioned object, the present invention provides a primary charging means for uniformly charging the image bearing member in the vicinity of the image bearing member, and an external charging means outside the image area. A blank exposing unit for forming a margin, a developing sleeve for applying a toner to the electrostatic latent image on the image carrier to form a toner image, and a transfer unit for transferring the toner image to a transfer material are provided. , A transfer bias control unit for turning off the transfer bias applied to the transfer unit at the time of returning after the occurrence of a jam, the transfer bias control unit being turned off, the primary charging unit, the blank exposing unit, and the developing sleeve. In an image forming apparatus having a bias control means in which at least one of them is turned off, or in the above-mentioned one, the transfer bias is turned off, and a polarity opposite to the transfer bias is applied to the image forming apparatus. An image forming apparatus for applying a bias.

With this configuration, when a jam occurs, it is possible to eliminate waste such that the unused transfer material in the transport path must be taken out when the transfer material is removed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [FIG. 1] FIG. 1 is a side view schematically showing an image forming apparatus as an embodiment of the present invention, having a cylindrical shape having an axis line in a direction perpendicular to the plane of the drawing and rotating in a direction indicated by an arrow. The photosensitive layer on the surface of the image carrier 1 is uniformly charged by the primary charger 2, and an image signal is applied to the charged surface to form an electrostatic latent image. Reference numeral 3 in the drawing denotes a blank exposure light source for forming a margin at the edge of the transfer material, and reference numeral 4 denotes a developing sleeve for applying the toner supplied from the toner container 40 to the latent image to form a toner image. Is.

With the rotation of the image carrier 1, when the toner image arrives at a transfer site where the image carrier 1 and the transfer charger 5 face each other, the transfer material 62 is supplied to the transfer site by this time. At the same time, a transfer bias is applied to the transfer charger 5, and the toner image on the side of the image carrier is transferred to the transfer material by the action of electrolysis thus formed.

After that, the transfer material carrying the toner image is conveyed to the fixing device section 7, where the toner image is fixed and fixed on the transfer material, and then discharged to the discharge tray 8 outside the machine.

In such an image forming apparatus, in the illustrated apparatus, a power source 21 for applying a charging bias to the primary charger 2 and a switch 22 for controlling the on / off of the primary charger 2 are provided with the blank exposure light source 3 Power source 31,
A switch 32 for controlling this is a power source 4 for charging the developing sleeve 4 and attaching toner to the developing sleeve 4.
1, a switch 42 serving as a control member thereof, a power supply 51 for applying a transfer bias to the transfer charger 5, and a control switch 52 for the transfer charger 5.

FIG. 2 is a schematic view of a transfer path of the transfer material from the transfer material supply portion 9 such as a cassette to the discharge tray 8 through the transfer portion and the fixing portion in the above apparatus. As described above, in the case of continuously forming images, it is usual that a plurality of transfer materials are simultaneously present in this conveyance path. In the case shown in the figure, the transfer material 61 is being subjected to the transfer action, and the transfer materials 62, 63, 64 and the like are in an unused state.

In such a state, when a jam occurs at any position, that is, when one of the sheets does not reach the predetermined position after a predetermined time elapses or the power is turned off, etc. Since the transfer material 61 already has toner adhered to a part thereof, the transfer material 61 proceeds as it is, is subjected to a fixing process, and is then discharged to the outside of the apparatus.

Since the transfer material after the transfer material 62 is in an unused state, the transfer bias is turned off before the transfer material 62 reaches the transfer portion so that the toner is prevented from adhering to the transfer material so that the transfer material is conveyed and discharged to the outside of the apparatus. To do. In this case,
Since the fixing process is unnecessary, the heater of the fixing device and the driving source may be cut off. Further, in this case, it is more effective not only to cut the transfer bias but also to positively block the transfer of the toner on the image carrier to the transfer material by applying a bias having a polarity opposite to that at the time of transfer. Is.

The control switch 22 turns off the primary charging bias, the blank exposure 3 illuminates the entire surface of the image carrier, and the developing sleeve control switch 42.
The effect is further improved by using one or several means for whitening the transfer material, such as turning off the light to prevent the toner from adhering to the sleeve.

[0017]

As described above, according to the present invention,
In an image forming apparatus that uses electrostatic transfer, after a jam occurs, at least a part of the image forming process is stopped when the jam occurs and all the transfer materials on the conveyance path are adhered to the image forming or the transfer material. Since the paper is discharged from the original discharge portion of the apparatus along the conveyance path without performing at least a part of the operation, it is possible to effectively avoid the waste of the unused transfer material due to the jam.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a side view of a main portion showing a mode in which a transfer material exists in a transfer material conveyance path of the above apparatus.

[Explanation of symbols]

 1 image carrier 2 primary charger 3 blank exposure light source 4 developing sleeve 5 transfer charger 7 fixing device 8 discharge tray 9 transfer material supply unit 22, 32, 42, 52 on / off control switch 21, 31, 41, 51 power supply

Claims (2)

[Claims] 1. A primary charging means for uniformly charging the image bearing body in the vicinity of the image bearing body, a blank exposing means for forming a margin outside the image area, and an electrostatic charge on the image bearing body. The latent image is provided with a developing sleeve for applying a toner to a toner image, and a transfer unit for transferring the toner image to a transfer material. When a jam occurs, the transfer bias applied to the transfer unit is turned off at the time of recovery. Image forming comprising a transfer bias control unit for turning off the transfer bias control unit, and a bias control unit for turning off at least one of the primary charging unit, the blank exposing unit, and the developing sleeve together with turning off the transfer bias controlling unit. apparatus. 2. The image forming apparatus according to claim 1, wherein the transfer bias is turned off and a bias having a polarity opposite to the transfer bias is applied to the transfer bias.