JPS5832706B2 - Exhaust oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In the copying process of various electrophotographic copying devices, the present invention provides
The present invention relates to a liquid developer removal device that uses corona discharge to remove excess liquid developer adhered to a transfer photoreceptor, transfer material, photosensitive sheet, etc.

More specifically, the present invention develops an electrostatic latent image formed on the surface of a transfer photoreceptor with a liquid, and then removes excess liquid developer that adhered to the transfer photoreceptor before transferring it to a transfer material. Liquid development to remove excess liquid developer adhered to the surface of the photosensitive sheet after liquid developing the excess liquid developer attached to the transfer material or the electrostatic latent image formed on the surface of the photosensitive sheet before fixing. This invention relates to a chemical removal device.

In a transfer-type wet-type electrophotographic copying device, an electrostatic latent image on the surface of a photoreceptor is generally developed with a liquid developer, and this developed image is transferred to a transfer material to fix the transferred image on the transfer material. The photoreceptor is cleaned by cleaning the residual developer remaining on the photoreceptor with a cleaning liquid in a cleaning device and is reused.

In such a conventional electrophotographic process, the copied image on the transfer material has looseness even in the bright areas of the original image.
Furthermore, the image was blurred and was extremely unclear and difficult to see.

This is because when the electrostatic latent image on the surface of the photoreceptor is developed, excess developer is attached to the surface, and the developer usually contains at least toner and carrier, and the white image of this toner Toner floating in areas other than the image area may be fixed as it is, or in the transfer method, it may transfer and adhere to non-image areas during transfer, or toner that is attracted to the image area may be transferred to the image area due to pressure during transfer, etc. It is thought that this is due to the negative influence of the carrier, ← flowing out with the flow, etc.

For this reason, conventionally, a squeezing roller or the like is arranged on the photoreceptor after development to squeeze out the excess developer.

However, it is inevitable that the use of this squeezing roller will cause image disturbances as in the case of transfer, and the use of a squeezing roller to remove excess developer on the transfer material will also cause similar image disturbances. It was inconvenient.

Further, when an electrostatic latent image on the surface of a photosensitive sheet is developed with a liquid and the excess developer on the photosensitive sheet is removed by a squeezing roller, image disturbance inevitably occurs.

Conventionally, in order to solve the above-mentioned problems, a liquid developer is produced by applying a corona discharge to a liquid developer on an image holding member such as a transfer photoreceptor, transfer material, or photosensitive sheet having a liquid developed image and charging it to an arbitrary polarity. was being removed.

However, in this case, since charging was performed with the same polarity as the retoner using a corona discharger, it had the following disadvantages.

That is, when a liquid developed image is transferred to a transfer material such as paper, if a certain amount of carrier liquid is not present, electrophoresis is difficult to occur and transfer efficiency deteriorates.

This is because when a corona discharge of the same polarity is applied, the surface potential of the image area and the electric field due to the corona discharge are larger than the surface potential of the non-image area and the electric field due to the corona discharge, so the amount of carrier liquid is larger in the image area. It is smaller than the non-image area.

Therefore, if the amount of liquid necessary for transfer remains in the image area, an even larger amount of carrier liquid will be present in the non-image area, and the transfer material will contain unnecessary carrier liquid. I think there is.

Therefore, if corona charging with the opposite polarity to the toner is performed, the amount of liquid in the image area will be greater than the amount of liquid in the non-image area, and the transfer material will contain only the carrier liquid necessary for transfer, resulting in a favorable result. It is thought that it can be obtained.

However, when a corona discharge with a polarity opposite to that of the toner is performed, the toner floats in the carrier liquid, causing the image to flow.
In reality, it was not suitable for practical use.

Accordingly, another object of the present invention is to improve an electrophotographic reproduction apparatus in which a toner image of a liquid developed image on an image holding member is fixed to the image holding member, and the carrier liquid and the toner suspended therein are squeezed out. An object of the present invention is to provide a liquid developer removing device.

Specifically, it is divided into two processes.

In the first step, the toner image is not disturbed.

The carrier liquid is then squeezed out in a second step.

That is, in the first step, corona discharge is applied so that the toner is charged with corona of the same polarity, and in the second step, corona discharge is applied so that the toner is charged with corona of the opposite polarity.

Here, the purpose of the corona discharge, which charges the toner in the first step with the same polarity, is to prevent disturbance of the toner image, so it is not necessary to apply it so strongly that it squeezes the carrier liquid.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on specific embodiments with reference to the drawings.

In FIG. 1, a photoreceptor 1, in which an insulating layer 1i, a photoconductive layer 1p, and a conductive support layer 1c are successively laminated as a photoreceptor, is mounted on a rotating drum, and a primary charger 2 uniformly charges the surface of the photoreceptor. (g) Then, at the same time as the image exposure, secondary charging or AC corona static elimination with the opposite polarity to the primary charging is performed using a corona discharge simultaneous exposure unit 3, and then full-surface exposure 4 is performed as necessary to form an electrostatic latent image. form.

This electrostatic latent image is then developed with a charged toner dispersed in an insulating carrier liquid in a liquid developing device 5, and then a developable image is formed on the transfer material T by a transfer corona discharger 6. The image is transferred and then fixed and copied using a fixing device.

Thereafter, the surface of the photoreceptor is cleaned by a cleaning blade 7 and returned to a reusable state.

In this device, the liquid developer removing device 8 of the present invention is disposed at a position after liquid development, thereby removing excess developer without disturbing the developer, thereby achieving efficient throttling.

Here, the liquid developer removing device will be described in detail.

The liquid developer removing device has a first corona discharger 81 and a second corona discharger 8□, and the photoreceptor developed by the liquid developer is transferred to the first corona discharger 8. to charge the toner with the same polarity ←) and fix the toner image on the photoreceptor.
Next, the second corona discharger 8□ charges the toner with a polarity opposite to that of the toner, and mainly removes the carrier liquid from the non-image area.

After this, the toner image on the photoreceptor is transferred to a transfer material by a transfer corona discharger.

When the photoconductor that has been cleaned after transfer enters the latent image forming section again, it is desirable that the surface potential be around OV, so it is desirable to apply an AC high voltage power source to the transfer corona discharger 6. In this case, In the present invention, in order to rapidly perform corona discharge in a narrow range by this second corona discharger, the applied voltage is adjusted so that transferable charging is performed with either positive or negative polarity. A convergence member 9 that converges corona discharge, such as an insulating member or a conductive member electrically insulated from others.
As a result, even if the amount of charge and the discharge potential from the corona discharge electrode to the holding member are lowered, the amount of charge and discharge potential from the corona discharge electrode to the holding member is much greater and narrower than when the member is not provided near the opening of the corona discharge. The squeezing removal effect of the insulating liquid becomes remarkable.

[Experiment example]

An electrostatic latent image is formed on a photoconductor, and transferred after liquid development.When the amount of carrier liquid contained in the transfer paper was measured to obtain an equivalent transferred image, it was removed by applying only a corona charge of the same polarity as the toner. 0.35 c, c per A4 size sheet
, , When the first corona discharger is removed by the second corona discharger as in the present invention, it is 0.26c, c, and when an insulating column member is provided at the opening of the second corona discharger, it is 0.26c.
22 c, c.

As explained in detail above, by applying the liquid developer removing device of the present invention, the following effects were noticeable.

By applying the device of the present invention to the transfer photoreceptor after liquid development and before transfer, a clear toner image containing a sufficient amount of carrier liquid for the transfer action is fixed on the photoreceptor surface, and most of the non-image areas are Since the carrier liquid was removed until it was no longer present, the transfer was carried out very well, and since the transfer material was obtained in a semi-dry state after transfer, the heat fixing was carried out smoothly.

Also, when removing the liquid developer on the transfer material to which the liquid-developed image has been transferred or the liquid developer on the photosensitive sheet on which the liquid-developed image has been transferred, by applying the liquid developer removing device of the present invention, generally the liquid developer can be removed. Even if there is a large amount of surplus liquid developer in the non-image area of the original image because the area is large, the apparatus of the present invention can provide a semi-dry transfer material or photosensitive sheet after processing.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of an electrophotographic copying apparatus to which the liquid side removal device of the present invention is applied, and FIG. 2 is a diagram of another embodiment of the device of the present invention. In the figure, 1 is a photoreceptor, 2 is a primary charger, 3 is a corona discharge simultaneous exposure device, 4 is a full surface exposure device, 5 is a liquid developing device,
6 is a corona discharger for transfer, 7 is a cleaning blade,
8 is a liquid developer removing device.

Claims (1)

[Claims] 1. In a liquid developer removing device that removes surplus liquid developer on an image holding member after liquid development by corona discharge, a toner having the same polarity as the toner contained in the developer on the image holding member is provided. A first corona discharger for charging and a corona discharge convergence member are provided in the discharge opening, and the first corona discharger is provided on the image holding member.
A liquid developer removing device comprising: a second corona discharger that performs charging with a polarity opposite to that of the corona discharger.