JPH03179376A - Transfer and carrying device - Google Patents

Abstract

PURPOSE:To surely separate a transfer paper from an image forming body by executing discharge only to one part from the head of the carrying direction of the transfer paper from a paper electrostatic charger and discharging a transfer unit after the non-image area of the transfer paper is passed. CONSTITUTION:The transfer paper P is supplied by a resist roller 5 and inserted between the paper electrostatic charger 6 and a turning roller 12 grounded through an insulating belt 11. Discharge from the charger 6 is started from the leading edge of the paper P and finished before the trailing edge of the paper P comes. Then, when the paper P is electrostatically attracted and carried by a carrying belt 10 and the non-image area of the paper P is passed through the transfer unit 20, the discharge is started by the unit 20 and a toner image is attracted in the image area of the paper P. Therefore, the non-image area of the paper P continues to be surely attracted by the belt 11 by static electrical power. Thus, the transfer paper P is surely separated from the image forming body 1.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an image forming apparatus using electrophotography,
In particular, the present invention relates to a transfer/conveyance device that electrostatically attracts and conveys a transfer paper and transfers a toner image onto the transfer paper.

[Conventional technology]

A transfer/conveyance device generally includes a conveyor belt, which is a belt made of an insulating material stretched around a pair of rotary rollers, at least one of which is grounded, and a charger that faces the grounded rotary rollers via the belt. The image forming apparatus includes a transfer device that discharges electricity to the image forming body through the belt, a static eliminator that eliminates static electricity from the belt, and a cleaning device that removes dust and toner from the belt. The operation of the conventional transfer/conveyance device will be explained below. A toner image is formed on the surface of the image forming body after being charged, exposed, and developed. When the transfer paper enters the belt from the registration roller, a charge with the same polarity as the toner is discharged from the charger toward the grounded metal roller.In other words, the transfer paper is discharged from the paper charger over the entire surface, and the belt Due to the charge applied to the paper, charges of different polarity are injected from the metal roller, and the entire surface of the transfer paper is attracted to the belt. The belt conveys the transfer paper by rotation of the rotating roller. When the transfer paper passes through the transfer device, the toner image is transferred from the image forming body to the transfer paper. At this time, the transfer device transfers the donor image from the image forming body to the transfer paper by discharging the entire surface of the transfer paper. The transfer paper is neutralized by a paper static eliminator, the binding force with the belt is reduced, and the paper is conveyed to the fixing device. After that, dust and toner on the belt are removed by a cleaning device.

[Problems to be solved by the invention]

Although there are drawbacks such as ozone generation due to corona discharge and increased discharge unevenness due to dust adhering to the wire, paper charging is performed to ensure separation in the transfer/conveyance device described above by attaching the leading edge of the transfer paper to a belt. The problem is that the purpose is to adsorb it to the surface, and the parts beyond the tip do not contribute to separation. SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a transfer/conveyance device whose purpose is to reliably separate transfer paper from an image forming body.

[Means to solve the problem]

This invention, which is distantly related to the above object, includes a conveyor belt in which the belt is stretched around a pair of rotating rollers with at least one side grounded, a paper charger facing the grounded rotating rollers, and an image A transfer/conveying device comprising a transfer device facing the forming body, the discharge from the paper charging electrode starts from the leading edge of the transfer paper, and the discharge ends before the trailing edge of the transfer paper arrives, and The transfer device is characterized in that the transfer device is discharged after the non-image area has passed. Here, the non-image area of the transfer paper refers to an area of the transfer paper where a toner image is not transferred from the image forming body. In this way, the non-image area of the transfer paper continues to be reliably attracted to the belt by electrostatic force, thereby making it possible to reliably separate the transfer paper from the image forming body, and minimizing the generation of ozone. Contamination of the wire can also be reduced as the discharge time is reduced.

【Example】

Next, embodiments of the present invention will be described based on the accompanying drawings. FIG. 1 is an explanatory diagram illustrating a non-image area on a transfer sheet in a transfer/conveyance device of the present invention, and FIG. 2 is a block diagram showing an embodiment of the transfer/conveyance device of the present invention. In FIG. 1, transfer paper P is conveyed in the direction of arrow X. Area A indicates a specific area from the beginning of the transfer paper P in the conveyance direction, and this area does not attract toner images. In addition,
The area excluding the non-image area is defined as the image area of the transfer paper P. The transfer/transport device 100 includes a transfer belt 10 and a paper charger 6.
and a transfer device 30. The transfer belt 10 includes a rotating roller 12 and a rotating roller 13 made of a conductive material such as metal.
A belt 11 is stretched between the belts 11 and 11, and a pressing roller 14 presses the belt 11 against the image forming body 1. The rotating roller 12
is grounded. The resistance of the belt used is around 1O100cm. The paper charger 6 is arranged to face the rotating roller 12 via the belt 11. The transfer device 20 is disposed opposite to the image forming body 1 with the belt 11 interposed therebetween. The transfer device 20 transfers the image forming body 1 via an insulating belt ll.
It has a corona discharge electrode 21 arranged to face the electrode 21 and a discharge opening, which surrounds the electrode except for this opening.
1 is a shield member 2 that is electrically insulated and grounded.
2 and a power source 28 that applies high voltage to the corona discharge electrode 21
It consists of In this configuration, a high voltage having a polarity different from the electric charge of the toner is applied to the corona discharge electrode 21, and a corona discharge is applied to the insulating bell 1-11, thereby generating an electric field on the surface of the image forming body 1 and the surface of the insulating belt. As a result, the toner is attracted onto the transfer paper P. Note that a static eliminator (not shown) that neutralizes the belt 11 and a cleaning device (not shown) that removes dust and toner from the belt II may be provided. The operation of the transfer/transport device 100 configured as above will be described below. First, the surface of the image forming body 1 is uniformly charged by the charger 2. After being charged, the image forming body 1 forms a latent image using an exposure device, and the latent image is made visible using toner in a developing device 4. The transfer paper P is fed from the registration roller 5, and the paper charger 6 and the insulating bell! It is inserted between rotating rollers 12 that are in contact with the ground via -11. The transfer paper P is charged by electric discharge in the paper band W unit 6 and is attracted to the belt by electrostatic force. At this time, the paper charger 6 applies charges to an area sufficient to obtain stable separation from the leading edge of the transfer paper P. The transfer paper P is electrostatically attracted to the conveyance bell 1 - 10 and conveyed, and then is pressed against the image forming body l by the pressing roller 14 and conveyed to the transfer device 20 . When the non-image area A of the transfer paper passes the transfer device 20, the transfer device 20 starts discharging and attracts the toner image to the image area of the transfer paper P. In other words, the transfer device 20 applies a high voltage having a polarity different from that of the toner to the corona emission TL electrode 21 so that the belt 11
The toner is attracted onto the transfer paper P by applying a corona discharge to the surface of the image forming member 1 and generating an electric field on the surface of the insulating belt. Here, the non-image area A of the transfer paper P is
By passing through I when no discharge occurs from 0, the non-image area A of the transfer paper P does not reduce the electrostatic force between the non-image area and the bell) 11 due to the discharge from the transfer device 20, so the transfer paper P can be reliably separated from the image forming body l. As described above, according to the transfer/conveyance device 100 of the present embodiment, only a portion of the transfer paper P from the beginning in the conveyance direction is charged by the paper charger 6 without being affected by environmental changes such as humidity. Since the transfer paper P is charged and electrostatically attracted to the belt and no corona discharge is performed by the transfer device 20 in the non-image area, the transfer paper P can be easily separated from the image forming body 20.

【Effect of the invention】

As explained above, the present invention includes a conveyor belt in which the belt is stretched around a pair of rotating rollers with at least one side grounded, a paper charger facing the grounded rotating rollers, and an image via the belt. In a transfer/conveyance device comprising a transfer device facing the forming body, the paper charger discharges only a portion from the beginning of the transfer paper in the conveyance direction, and the charger discharges electricity from the paper charger only after the non-image area of the transfer paper has passed. By discharging the transfer device, it is possible to reliably separate the transfer paper from the image forming body, and it is also possible to provide a transfer/conveying device that suppresses the generation of ozone and the occurrence of discharge unevenness due to wire dirt. did it.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating a non-image area on transfer paper in the transfer/conveyance device of the present invention, and FIG. 2 is a diagram showing an embodiment of the transfer/conveyance device of the present invention. l... Image forming body 6... Paper charger 10...
Conveyor belt 12.13... Rotating roller 20.
・・Transfer device

Claims (1)

[Claims] It consists of a conveyor belt in which the belt is stretched around a pair of rotating rollers with at least one side grounded, a paper charger that faces the grounded rotating rollers, and a transfer device that faces the image forming body via the belt. In the transfer/conveyance device, the discharge from the paper carrying electrode is started from the leading edge of the transfer paper, the discharge is finished before the trailing edge of the transfer paper comes, and the transfer device is started after the non-image area of the transfer paper has passed. A transfer/conveyance device characterized by electric discharge.