JPS599231Y2 - electronic copying device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wet-type electronic copying apparatus using a so-called visible image transfer method.

FIG. 1 schematically shows only the essential parts of an example of a visible image transfer type wet type electronic copying apparatus.

That is, the main parts of the electronic copying apparatus include a photosensitive drum 1, which is a conductive drum with a photoconductor layer provided on its circumferential surface, a corona charger 2 for charging, an exposure optical system 3, and a charge eliminating system. AC corona charger 4, developing device 5, cleaning roll 6, cleaning blade 7, squeeze roll 8
, a developer tank 9 containing a developer, a transfer device 10, a quenching lamp 11 for static elimination, a transport device 12 for transporting the document O, and a light source lamp 13.

Copying by this device is performed as follows.

First, the photoreceptor drum 1 rotates counterclockwise, and when the charger 2 uniformly charges its surface, the document O is moved in the direction of the arrow by the conveyance device 12, and the document O is moved by the light source lamp 13 and the exposure optical system 3. On the surface of the photosensitive drum 1, an electrostatic latent image corresponding to the original image is formed.

This electrostatic latent image is supplied with a developer and visualized in a so-called cascade type liquid developing device 5.

This visible image is transferred onto the recording sheet S by the transfer device 10.

In this way, a copy image corresponding to the original can be obtained on the recording sheet S.

After the visible image is transferred onto the recording sheet S, the charge remaining in the photoconductor layer of the photoconductor drum 1 is removed by the quenching lamp 11, and the charge remaining on the surface of the photoconductor layer is The static electricity is removed by the AC corona charger 4.

In such a liquid electrocopying apparatus using a visible image transfer method, the cleaning process for removing residual toner remaining on the surface of the photosensitive drum 1 after the visible image is transferred onto the recording sheet S is extremely difficult. is important.

If such residual toner is left on the surface of the photoreceptor drum without being removed, it may stain the recording sheet or deteriorate the performance of the photoreceptor drum in the next copying process.

Additionally, if a developer film exists on the drum surface before charging, the toner in the liquid film will adhere to the drum surface due to the charging action and will be transferred together with the developed image during the next transfer. This causes a so-called fog phenomenon.

Now, in the electronic copying apparatus, residual toner is removed in the following manner.

That is, after the residual charge on the surface of the photosensitive drum 1 is removed by the AC corona charger 4, it is washed with a developer supplied by the developing device 5, and a part of the residual toner on the surface is transferred to the developer tank 9. The toner is washed away, and other toner becomes easily peeled off.

Then, the cleaning roll 6 comes into pressure contact with the surface of the photoreceptor drum 1, and the toner, which is already in a state where it is easy to peel off, is removed from the surface of the photoreceptor drum 1.

Incidentally, behind the cleaning blade 7 with respect to the rotational direction of the photoreceptor drum 1, there is a squeeze roll 8 that removes excess developer on the surface of the photoreceptor drum 1 during the developing process by the developing device 5. Although they are provided close to each other, this gap is, for example, about 0.05 mm, and a pool of developer is generated in this gap due to surface tension.

In the cleaning process after the transfer and charge removal, the cleaning roll 6 and the cleaning blade 7 come into pressure contact with the surface of the drum 1, thereby removing the developer as a cleaning liquid along with the residual toner, and removing the residual toner from the photosensitive drum 1. Cleaning blade 7 on the surface of
The surface between and the squeeze roll 8 is in a dry state.

However, a pool of developer has already formed in the gap between the photoreceptor drum 1 and the squeeze roll 8, and as the drum 1 rotates, the developer is applied to the surface of the drum until the pool runs out. As shown in FIG.
This has the drawback that a liquid pattern is produced, which appears as abnormal stains on the copied image on the transfer paper S during the next copying.

In order to eliminate such defects, it may be possible to increase the gap between the photoreceptor drum 1 and the squeeze roll 8 to prevent the developer from pooling. It is not possible to obtain a developer layer that is uniform and has an appropriate thickness.

Incidentally, in this type of copying apparatus, a cleaning blade 7 as shown in FIG. After the surface of the body drum has been neutralized, the cleaning blade is brought into contact with the drum surface to remove residual toner, and a special cleaning liquid is supplied near the contact position,
There is a type of copying machine that flushes away the toner.

However, such a copying device requires a separate device to supply cleaning liquid to the cleaning section, and also requires a special tray to collect the liquid, which makes the device complicated. There are drawbacks that cannot be overlooked.

In view of the above-mentioned points, the purpose of the present invention is to organically arrange a developing device, a cleaning device, and a surplus developer removing device on the lower side of the photoreceptor drum, and to prevent abnormal stains on transfer paper caused by liquid pooling. In addition to cleaning the surface of the photoreceptor drum using the developing solution supplied by the developing device, an extremely simple cleaning device that does not require the various devices associated with the cleaning solution as described above can be created. The purpose is to provide electronic copying equipment that is equipped with the equipment.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows only the essential parts of an example of an electronic copying apparatus embodying the present invention.

That is, in the figure, around the photoreceptor drum 20, in the direction of rotation, there are a quenching lamp 11, a corona charger 2, an AC corona charger 4, a developing device 21, a cleaning roll 22, a squeeze roll 23, and a cleaning member serving as a quenching member. A blade 24, a transfer device 10, etc. are arranged in this order.

Of these, cleaning roll 22, Ku quiz roll 2
3 and the cleaning blade 24 are connected to the photoreceptor drum 2.
It is arranged near the peripheral surface on the lower side of 0.

Further, a developer tank 25 containing a developer is placed below these.

The developing device 21 is a so-called cascade type liquid developing device, and includes a pump 21a, a liquid supply pipe 21b, a gushing portion 21C, and a counter electrode plate 21d. Development is carried out by pumping up a developer into the liquid pipe 21b and flowing the developer gushing out from the gushing portion 21C into the gap between the photosensitive drum 20 and the counter electrode plate 21d.

The cleaning roll 22 is made of a porous elastic material, and is arranged at a position relatively close to the counter electrode plate 21 d, and is configured to be able to move toward and away from the surface of the photoreceptor drum 20 .

When the cleaning roll 22 comes into contact with the surface, it removes the residual toner on the surface.

The squeeze roll 23 has a surface that is similar to the photoreceptor drum 20.
It is arranged so as to be very close to the surface of the photosensitive drum 20 and rotates counterclockwise at all times to remove excess developer from the surface of the photoreceptor drum 20 and form a developer film of uniform thickness. , the excess developer is dropped into the developer tank 25.

The cleaning blade 24 is made of an elastic material such as polyurethane rubber, and is attached to the cleaning roll 22.
At the same time, it is movable toward and away from the surface of the photoreceptor drum, and upon contact, removes the developer film from the surface and leaves the surface clean.

Now, here is the fourth copying process using the electronic copying device.
This will be explained with reference to the timing chart shown in the figure.

First, when a copying operation is started and the photosensitive drum 20 starts rotating in the direction of the arrow, the quenching lamp 11, AC corona charger 4, developing device 21,
The cleaning roll 22, cleaning blade 24, and transfer device 1o are operated.

Note that the operation of the developing device 21 is performed by the pump 21.
This means that the developer is supplied by the operation of a.

Further, the operation of the cleaning roll 22 and the cleaning blade 24 means that both come into contact with the photoreceptor drum 20.

On the other hand, as the drum 20 rotates, the corona charger 2 is activated just before the tip of the area on the drum where the image is to be formed reaches the corona charger 2.
Further, just before the tip reaches the exposure position on the drum facing the exposure optical system 3, the light source lamp 13 is turned on.

The drum surface is uniformly charged by the operation of the corona charger 2, and an electrostatic latent image is formed on the drum surface through the exposure optical system 3 by the operation of the light source lamp 13.

The electrostatic latent image is then visualized by force scale development by the developer device 21.

On the other hand, just before the tip reaches the cleaning roll 22 and the cleaning blade 24, the operation of both is canceled and both are separated from the drum.

During this time, the squeeze roll 23 rotates counterclockwise,
Performs the function of removing excess developer.

On the other hand, as the drum continues to rotate, the transfer device 10 starts to transfer the visible image formed on the drum onto the recording sheet S.

On the other hand, after the rear end of the image-forming area passes through the corona charger 2 and the exposure position, the corona charger 2 and the light source lamp 13 are deactivated.

Next, during the second rotation of the drum 20, after the rear end of the image-forming area passes through the AC corona charger 2, this is activated to eliminate static electricity.

Further, after the rear end passes through the cleaning roll 22 and the cleaning blade 24, both of them are activated and come into contact with the drum surface, respectively.

During this time, the surface of the photoreceptor drum 20 is washed by the developer supply accompanying the subsequent operation of the developing device 21, and some of the residual toner on this surface is washed into the developer tank 25, and other toner is washed away. The toner becomes easily peeled off.

This easily peeled toner is completely removed by the cleaning roll 22 that is in contact with the drum surface, and the developer film adhering to the photoreceptor drum is thoroughly removed by the cleaning blade 24 and the photoreceptor The surface of the body drum 20 becomes clean.

As described in the conventional embodiment, the developer held between the squeeze roll 23 and the surface of the photoreceptor drum 20 is completely removed by the cleaning blade 24, and the surface becomes dry. Since the next copy can be started in this state, there is no risk of abnormal staining of the copied image on the transfer paper due to the wavy liquid pattern as in the conventional embodiments or the above-mentioned fogging phenomenon.

Further, since the developing device 21, the canceling roll 22, the squeeze roll 23, and the cleaning blade 24 are arranged on the lower side of the photoreceptor drum 20, the developer can be easily collected, and the developer can be used as a cleaning solution. Therefore, there is no need to provide a special supply device or recovery device for the cleaning liquid.

In this way, the surface of the photoreceptor drum 20 is in a dry state with the developer film removed and in a still state with residual toner removed, for the next copying operation, that is, at the third rotation of the drum. You can enter the image process.

In addition, when copying only l sheets, the cleaning roll 22 and the nooning blade 24 are separated from the drum when the copying apparatus is stopped after the drum has completed the second copy.

In addition, in the case of continuous copying, the cleaning roll 22 and cleaning blade 24 are maintained in a state in continuous contact with the drum even when the drum shifts from the second rotation to the third rotation, and the timing of contact and separation between the two is maintained. is performed at the same timing as the first time the drum is played.

In this manner, in this copying apparatus, the drum rotates twice to obtain one copy.

It goes without saying that the present invention can also be applied to other known developing devices other than those using the cascade method.

As described above, according to the present invention, it is possible to prevent abnormal stains on the transfer paper due to liquid accumulation, and the surface of the photoreceptor drum can be cleaned using the developer. There is no need for a supply device or a collection device for cleaning liquid, and therefore an electronic copying device equipped with an extremely simple cleaning device can be provided.

[Brief explanation of drawings]

Figure 1 shows one example of a conventional visible image transfer type wet-type electronic copying device.
FIG. 2, a front view showing only the main parts of an example, shows a state in which a wavy liquid pattern is generated on the surface of the photoreceptor drum when the developer runs out, which is caused by a pool of developer between the drum and the squeeze roller. FIG. 3 is a front view showing only the main parts of an example of an electronic copying apparatus embodying the present invention, and FIG. 4 is a timing chart of the copying process of the electronic copying apparatus. 2... Corona charger 4... AC corona charger, 10... Transfer device, 11... Quenching lamp, 13... Light source lamp, 20... Photoreceptor,
21...Developing device, 22...Cleaning roll,
23... Squeeze roll, 24... Cleaning member, S... Recording sheet.

Claims (1)

[Scope of utility model registration request] While rotating a photoreceptor having a circumferential length greater than the length of the maximum original, an electrostatic latent image corresponding to the original is formed on the surface of the photoreceptor, and the electrostatic latent image is transferred to a developing solution. In an electronic copying apparatus of the type in which the visible image is transferred onto a recording sheet, a quenching lamp for static elimination, a corona charger for charging, and a static elimination lamp are installed around the photoreceptor in the rotational direction. AC corona charger for use with the photoconductor, a developing device that supplies developer to the photoconductor surface, a cleaning roll that can freely touch and separate from the photoconductor surface to remove residual toner on the surface, and a cleaning roll that removes excess developer on the photoconductor. A squeeze roll that forms a developer film of uniform thickness, a cleaning member that can freely come into contact with and separate from the photoreceptor surface and remove the developer film from the photoreceptor surface to clean the surface, and a transfer device are installed in sequence. A cleaning roll, a squeeze roll, and a cleaning member are installed below the photoconductor, and as the photoconductor starts its first rotation, a quenching lamp and an AC corona charger are installed. , the developing device, the cleaning roll, the cleaning member, and the transfer device are operated, and immediately before the leading edge of the image forming area reaches the corona charger and the exposure position, the corona charger and the light source lamp are activated, and the leading edge of the cleaning roll is Immediately before reaching the cleaning roller and cleaning member, the cleaning roll and the cleaning member are deactivated, and after the rear end of the image area passes through the corona charger and the exposure position, the corona charger and the light source lamp are deactivated. release, then
During the second rotation of the photoconductor, after the rear end passes an AC corona charger, actuate it, and after the rear end passes a cleaning roll and a cleaning member,
The cleaning roll and the cleaning member are respectively operated, and in this state, the surface of the photoreceptor is cleaned by the supply of developer accompanying the subsequent operation of the developing device, and the cleaning roll and the cleaning member are
An electronic copying device characterized in that residual toner and a developer film are removed.