JPS628052Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Technical field) The present invention relates to a wet transfer type electrophotographic apparatus.

(Prior Art) Wet transfer type electrophotographic devices have been known for a long time. FIG. 1 schematically shows only the main parts of a typical example of this type of electrophotographic apparatus.

That is, the main part of the electronic copying machine is a so-called photoreceptor drum 1, which is a conductive drum with a photoconductor layer provided on its circumferential surface.
, a charger c1 for corona discharge, and an exposure optical system m1, m consisting of a combination of a lens and a reflecting mirror.
2, m3, m4, a liquid developing device 2, a transfer device 3 that transfers a visible image onto a recording sheet s, an AC corona charger c2 that removes charges on the surface of the photoconductor drum 1, and a a quenching lamp 5 for removing residual charges, a cleaning blade 6,
It consists of a document transport table 7 for conveying the document O, and a light source 8 for illuminating the document. Copying by this electronic copying machine is performed as follows. First, when the photosensitive drum 1 rotates counterclockwise and the charger c1 uniformly charges its surface, the document transport table 7 on which the document O is placed moves in the direction of the arrow, and is illuminated by the light source 8. In addition, the reflected light from the original O is guided to the uniformly charged surface of the photosensitive drum 1 by optical systems m1, m2, m3, and m4 fixed at fixed positions, and is reflected onto the original O. A corresponding image is formed, and an electrostatic latent image corresponding to the original O is formed on the surface of the photoreceptor drum 1. This electrostatic latent image is supplied with a developer in a liquid developing device 2 and is turned into a visible image. The visible image is transferred onto the recording sheet S by the transfer device 3. In this way, a copy image corresponding to the original can be obtained on the recording sheet S. The visible image is on the recording sheet S
After being transferred onto the surface of the photoconductor drum 1, the potential remaining on the surface of the photoconductor drum 1 is removed by an alternating current corona charger c2, and the charge remaining in the photoconductor layer is removed by a quenching lamp 5. Static electricity is removed.

In such a wet-type electronic copying machine using a visible image transfer method, the cleaning process for removing residual toner remaining on the surface of the photoreceptor 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 in the next copying process or cause deterioration of the performance of the photoreceptor drum. be.

In the electronic copying machine, residual toner is removed by pressing the edge of the cleaning blade 6 against the surface of the photosensitive drum 1. In such an electronic copying machine, the cleaning position of the photoreceptor drum 1 is, of course, the position where the surface of the photoreceptor drum 1 is freshly cleaned by the charger c1 after the visible image is transferred onto the recording sheet. Since the cleaning blade 6 is only used until it is charged, the cleaning blade 6 is located above the developing device 2 due to the structure of the device. A cleaning liquid is supplied near the position where the edge of the cleaning blade 6 contacts the surface of the photoreceptor drum 1. This is to wash away toner particles separated from the surface of the photoreceptor drum 1 so that the toner particles separated from the surface of the photoreceptor drum 1 do not accumulate on the edge portion of the cleaning blade 6. According to
This is also because the surface of the photoreceptor drum 1 is not damaged. Generally, the developer itself is most often used as the cleaning solution. Therefore, in the electronic copying machine as shown in FIG. 1, a means for supplying the developer as a cleaning liquid to the vicinity of the cleaning blade 6 is required.

Further, since the cleaning liquid is supplied above the transfer device 3, the cleaning liquid may flow toward the transfer device 3, which has the drawback of staining the recording sheet S. Furthermore, since the cleaning section is located above the charger c1, the flowing liquid may stain the charger c1 or prevent uniform charging.

(Purpose) The purpose of this invention is to solve the above problems.
The present invention provides a wet transfer type electrophotographic device.

(composition) The present invention will be explained below.

The wet transfer type electrophotographic apparatus of the present invention includes a cascade developing device, a cleaning member, a contacting and separating means, a transfer device, a charger, and a static elimination charger.

The cascade developing device includes a developer tank, a counter electrode plate, and a developer supply means. The developer tank is arranged below the photoreceptor. The counter electrode plate is arranged on the side of the photoreceptor so as to face the surface of the photoreceptor. The developer supply means draws up the developer from the developer tank and supplies it between the surface of the photoreceptor and the counter electrode plate.

The cleaning member is below the photoreceptor,
It is disposed near the counter electrode plate, operates after the visible image is transferred, and removes residual toner on the surface of the photoreceptor with the developer supplied by the developer supply means.

Further, the approaching/separating means causes the cleaning member to approach/separate from the surface of the photoreceptor.

The transfer device is disposed downstream of the cleaning member and to the side of the photoreceptor, and transfers the visible image on the photoreceptor onto the recording sheet.

The charger and the static elimination charger are located further downstream than the transfer device and above the photoreceptor.

Hereinafter, specific embodiments will be described with reference to the drawings.

FIG. 2 shows only the essential parts of an electronic copying machine, which is an example of a wet transfer type electrophotographic apparatus embodying the present invention.

That is, the main parts of the electronic copying machine include the photosensitive drum 1
0, exposure optical system 11, charger 12, developing device 13, squeeze roll 14, transfer device 15, quenching lamp 16, AC corona charger 17, cleaning roll 18a as a cleaning member, and cleaning blade 18
b, a developer tank 20 containing the developer 19, a pair of transport rollers 21a, 21b that transports the original O;
22a, 22b, a contact glass 23, a guide 24, and a light source lamp 25.

The photosensitive drum 10 is a conductive drum provided with a photoconductive layer on its circumferential surface, and rotates in the direction of the arrow, that is, in the counterclockwise direction. The exposure optical system 11 provided between the top of the photoreceptor drum 10 and the document surface has a third
As shown in the figure, a large number of light-focusing glass fibers 11i with uniform lengths are bundled parallel to each other, and individual glass fibers 11i are arranged at both ends of the bundle.
1i are aligned so that the collective surfaces of the end faces form a slit-like surface and fixed with a resin holder 11a. Self-oct (trade name) is used as the light-focusing glass fiber. Self-offering is
Its refractive index is symmetrical about the axis of the glass fiber,
It varies in the radial direction. That is, when the refractive index on the central axis of the self-lock is set to no, the refractive index n at the position of the radius y is given by the following equation.

n=no(1-1/2Ay ² ) (1) Therefore, the optical path of the light that travels through the self-lock in the length direction of the fiber (assuming the x direction) is the differential of d ² y/dx ² = -Ay (2) The equation is satisfied, therefore, the light travels through the self-locking device in a sinusoidal curve, and its period is
2π/√, determined by the constant A in equation (1). Due to these refractive index characteristics, each fiber of Self-Otsuku can play the role of a lens, and when viewed as a lens, its focal length is extremely small. The exposure optical path length can be greatly reduced.

The developing device 13 is a so-called liquid cascade developing device, and includes a pump 13a, a liquid supply pipe 13b, a gushing portion 13c, a counter electrode plate 13d, and a developer tank 2.
The developer 19 in the developer tank 20 is pumped up into the developer supply pipe 13b by the pump 13a, and the developer gushing out into the gushing part 13c is transferred to the photoreceptor drum 10 and the counter electrode plate 13d. Developing is carried out by flowing it into the gap between the two. The squeeze roll 14 has its surface extremely close to the surface of the photoreceptor drum 10 and rotates counterclockwise to remove the surface of the photoreceptor drum 10 after development.
Scrape off excess developer from the surface of the developer into the developer tank 20. The transfer device 15 includes a photosensitive drum 10
The visible image formed by the toner is recorded on the recording sheet S.
Transfer on top. The quenching lamp 16 irradiates the surface of the photoreceptor drum 10 with light after the visible image has been transferred to the recording sheet S to release the charges trapped inside the photoconductive layer of the photoreceptor drum 10. Eliminate static electricity. The AC corona charger 17 neutralizes and eliminates the charge of the electrostatic latent image partially remaining on the surface of the photoreceptor drum 10. Cleaning roll 18
A is made of a porous elastic body, and is pressed against the surface of the photoreceptor drum as required. The edge of the cleaning blade 18b can also be brought into contact with the surface of the photoreceptor drum 10 as necessary. Among the pair of transport rollers, the rollers 21b and 22b can be released from contact with each other as necessary. Further, the guide 24 can also be removed from the contact glass 23 if necessary. That is, when the original O is in the form of a sheet, the original is scanned in a state as shown in FIG. If the original O is a book, etc., the rollers 21b, 22b and the guide 24 of the pair of transport rollers are retracted upward in FIG. 2, and the original placed on a transparent carrier (not shown) is removed. is conveyed by rollers 21a and 22a.

Now, the copying process by the electronic copying machine will be explained below. When the electronic copying machine is operated, the photosensitive drum 10 starts rotating and the charger 12
charges its surface uniformly. During this time, the light source lamp 25 emits light. When the original O is fed by the pair of transport rollers 21a and 21b, the original O passes through a path formed by the contact glass 23 and the guide 24, and the original surface is scanned by the exposure optical system 11, and the photoreceptor drum 10 An electrostatic latent image of the document O is formed on the surface of the document O.

The photosensitive drum 10 rotates further, but at this time the AC corona charger 17 is not operating. The electrostatic latent image is then developed into a visible image by liquid cascade development by the developing device 13. At this time, the cleaning roll 18a and the cleaning blade 18b are released from contact with the photoreceptor drum 10. Next, the residual developer on the surface of the photosensitive drum 10 is removed by the squeeze roll 14, and the visible image is transferred onto the recording sheet S by the transfer device 15, and a copy image corresponding to the original O is formed on the recording sheet S. is obtained.

After the visible image is transferred onto the recording sheet S, the charge inside the photoreceptor layer of the photoreceptor drum 10 is removed by a quenching lamp 16. Then,
Before scanning the document again, the application of the corona discharge voltage to the charger 12 is stopped, the light source lamp 23 stops emitting light, and a discharge voltage is applied to the AC corona charger 17. , the photosensitive drum 10 is rotated. Then, the residual charge on the surface of the photoreceptor drum 10 is removed by AC corona discharge by the AC corona charger 17, and the surface is washed with the developer supplied by the developing device 13, and the A portion of the residual toner on the surface is washed into the developer tank 20, leaving other toner susceptible to peeling.
When the surface portion that was initially neutralized by the AC corona charger 17 reaches the lower end of the counter electrode plate 13d, the cleaning roll 18a and the cleaning blade 18b are pressed against the surface of the photoreceptor drum 10 and cleaned. The roll 18a rotates to wipe the toner, which has already become easily peeled off, from the surface of the photoreceptor drum 10. When the photoreceptor drum 10 rotates one more rotation from this state, the residual toner is removed from the surface of the photoreceptor drum 10 and the surface becomes clean. If the photoreceptor drum 10 does not have a starting position and copying can be performed from an arbitrary state, use this state, or if the photoreceptor drum 10 has a fixed starting position, then move the photoreceptor drum 10 to the starting position. In the rotated state, preparation for the next copying process is completed, and one copy is obtained each time the above-described process is repeated.

(Effects) As described above, according to the present invention, a novel wet transfer type electrophotographic device can be provided. With this electrophotographic device,
The cleaning section is located below the photoreceptor, so
The cleaning liquid does not stain the recording sheet or impair the charger function. In addition, since the surface of the photoreceptor drum can be washed with the developer, there is no need to press the cleaning blade as a cleaning member against the photoreceptor so strongly, and therefore the photoreceptor is not damaged by the cleaning blade. Not often. It goes without saying that the present invention can be applied to a belt-shaped photoreceptor.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing only the essential parts of an example of a conventional wet transfer type electrophotographic device using a visible image transfer method, and FIG. FIG. 3 is a front view showing only the essential parts of an example of a photographic apparatus, and FIG. 3 is a perspective view showing the structure of the exposure optical system indicated by reference numeral 11 in FIG. O... Original, 10... Photosensitive drum, 13...
Developing device, 11... Exposure optical system, 18... Cleaning roll.

Claims (1)

[Claims for Utility Model Registration] An electrostatic latent image corresponding to the original is formed on the surface of a rotating photoreceptor, the electrostatic latent image is made into a visible image using a developer, and the visible image is placed on a recording sheet. It is an electrophotographic device of the type that transfers images to a photoreceptor, and a developer tank placed below the photoreceptor faces the surface of the photoreceptor extending from near the top to near the bottom of the photoreceptor at the side of the photoreceptor, with a predetermined gap maintained. and a developer supply means for pumping up a developer from the developer tank and supplying the developer between the photoconductor surface and the counter electrode plate from above the counter electrode plate. a cascade developing device, which is disposed below the photoreceptor near the lower end of the counter electrode plate, and is activated after the visible image is transferred, and a developer is supplied from the lower end of the counter electrode plate through the cascade developing device; a cleaning member for removing residual toner on the surface of the photoreceptor using a cleaning liquid; a means for moving the cleaning member toward and away from the surface of the photoreceptor; 1. A wet transfer type electrophotographic apparatus, comprising: a transfer device; and a charger and a static eliminator disposed downstream of the transfer device and above a photoreceptor.