JPS6326673A - Dry type electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To reduce the residence of ozone, and to prevent an image flow by using a transfer/separation charger whose output is stopped immediately, after the rear end of a developed image passes through a transfer/separation part, before a photosensitive body stops. CONSTITUTION:In a transfer/separation part opposed to a transfer/separation charger 9, the tip of a developed image on a photosensitive body 1, and the tip of transfer paper S fed from a paper feeding device meet in a good opportunity, and the developed image on the photosensitive body 1 is transferred to the transfer paper S by a corona discharge by a transfer charger 10. After this transfer, destaticization is executed by a separation charger 11, and the transfer paper is separated from the photosensitive body. In such a case, as for the transfer/separation charger 9, its output is stopped immediately, after the rear end of the developed image on the photosensitive body 1 passes through the transfer/separation part. In this way, an image flow can be prevented without requiring an ozone discharge fan, etc.

Description

[Detailed description of the invention] Skin 1 Ice Random The present invention relates to a dry type electrophotographic copying machine.

In the U1 dry-type electrophotographic copying machine, an electric discharge from a transfer/separation charger is used to transfer a toner image on a photoreceptor to a transfer paper, and to separate the transfer paper from the photoreceptor. Generally, such a transfer/separation charger starts its output at the same time as the photoreceptor starts rotating.
When the photoreceptor stops, its output is also stopped.

By the way, when the copying machine is left in a high-temperature environment, image deletion occurs on the photoreceptor, and this image deletion tends to occur at a portion facing the transfer/separation charger. It is well known that ozone is generated from the transfer/separation charger as it discharges.

It is believed that the oxides generated by this ozone are humidified in a high-humidity environment and become low in resistance, causing charge to escape and causing image deletion. This occurrence is also due to the fact that unlike wet-type electrophotographic copying machines, which form a developer film on the photoreceptor surface, dry-type electrophotographic copying machines directly expose the photoreceptor surface. There is.

Conventionally, as a measure to prevent such image deletion, a method has been taken in which warm air from the fixing section is sent to the photoreceptor, but in this method, the photoreceptor is heated only after the temperature of the fixing section has risen. Because the printer is warmed up, it takes a certain amount of time to start copying.

The disadvantage is that the cost increases because a blower fan must be added. In addition, a method has been proposed in which ozone is discharged by blowing air directly to the transfer/separation charger.
This method has the disadvantage that the transfer/separation charger is easily contaminated with toner, causing toner scattering, and also increases costs.

SUMMARY OF THE INVENTION An object of the present invention is to prevent the occurrence of image deletion on a photoreceptor, without relying on the above-mentioned conventional example.

1. In order to achieve the above object, the present invention relates to a dry type electrophotographic copying machine according to the present invention, and a photoreceptor that is charged in a --like manner and forms an electrostatic latent image by imagewise exposure.

A dry developing device that visualizes the electrostatic latent image with toner, and a dry developing device that is arranged opposite to the photoreceptor and transfers the image to the transfer paper and separates it by electric discharge, and the trailing edge of the image transfers the image to the transfer paper and separates the two. It is characterized by having a transfer/minute charger whose output is stopped immediately after passing through.

The present invention will be explained below based on one embodiment.

In FIG. 1, a drum-shaped photoreceptor 1 is rotationally driven in the direction of the arrow. The charger 2 is connected to a high voltage power source 4 controlled by the CPU 3, and the surface of the photoreceptor 1 is uniformly charged by the connected charger 2. In addition,
Here, it is positively charged.

An eraser 5 erases charges on unnecessary portions of the uniformly charged surface of the photoreceptor, and then image exposure is performed in an exposure section 6 to form an electrostatic latent image on the surface of the photoreceptor. . This electrostatic latent image is visualized with the developing toner of the dry developing device 7.

The surface of the photoreceptor having a developed image is uniformly exposed by a pre-transfer lamp 8, and its surface potential is lowered in order to increase the transfer efficiency.

The transfer/separation charger 9 connected to the voltage type [18] is arranged below the photoreceptor 1 with an opening facing the photoreceptor, and the transfer charger 10 and separation charger 11
It is composed of.

In the transfer 9 separation section facing the transfer/separation charger 9, the developing tip on the photoreceptor and the tip of the transfer paper S fed from a paper feeding device (not shown) are arranged to meet at an opportune time, From this meeting.

The developed image on the photoreceptor is transferred onto the transfer paper S by corona discharge by the transfer charger 10.

After this transfer, static electricity is removed by a separation charger 11, and the transfer paper is separated from the photoreceptor.
If the transfer paper is not separated by 1, use separation claw 1.
3, the transfer paper is forcibly peeled off from the photoreceptor.

On the other hand, the developing toner that has not been transferred is transferred to the voltage power source 17.
A pre-cleaning charger 14 connected to the cleaning device 14 applies a charge to the photoreceptor, and a cleaning device 15 removes the charge from the photoreceptor. Then, static electricity is removed from the surface of the photoconductor by the static elimination lamp 16 to erase the residual charge, and in this state,
The photoreceptor is then used for copying.

The present invention is characterized by the use of a transfer/separation charger that stops outputting immediately after the rear end of the developed image on the photoreceptor passes through the transfer/separation section. be.

It has already been mentioned that ozone is generated by the discharge of the transfer/separation charger, but since this generated ozone is heavier than air, due to the unique configuration of the charger, which is installed with the opening facing upward, there is Ozone tends to stay in the environment. This further accelerates the occurrence of the image deletion mentioned above.

Conventionally, a transfer/separation charger was used that started up its output at the same time the photoreceptor started rotating and continued to output until the photoreceptor stopped. Before the body stops, the rear end of the image is transferred.

It uses a transfer/separation charger whose output is stopped immediately after passing through the separation section.

Retention of ozone is reduced and one image deletion can be prevented. Particularly in high temperatures, during the morning shift,
Image blurring had been occurring at the portion of the photoreceptor facing the separation charger, but by taking the above measures, this occurrence has been prevented.

It is to be noted that it will be more effective if an opening is provided at the bottom of the casing of the transfer/separation charger and a means is taken in conjunction with which ozone is discharged by its own weight.

Note that FIG. 2 shows a timing chart of each copying process step of the copying machine.
At the same time as the photoreceptor starts rotating, its output is started,
The output is stopped at the same time as charging and exposure are completed.

Toyoizumi As described above, according to the present invention, there is provided a dry electrophotographic copying machine that can prevent image blurring without requiring an ozone exhaust fan, and can achieve low cost and simple configuration functions. machine can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 is a timing chart of copying process steps in the same embodiment.

Claims (1)

[Claims] A photoreceptor that is uniformly charged and forms an electrostatic latent image by image exposure; a dry developing device that visualizes the electrostatic latent image with toner; The image transfer and its separation are carried out, and the rear end of the image is the transfer,
A dry type electrophotographic copying machine characterized by being equipped with a transfer/separation charger whose output is stopped immediately after passing through a separation section.