JPH0570819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a corona discharger used in electrophotographic copying machines and the like, and particularly to a cleaning device for this corona discharger.

[Prior Art] Conventionally, in an electrophotographic copying machine, as shown in FIG. 6, the surface of a photoreceptor a rotating in the direction of arrow A is charged by a corona discharger b, and an optical system c is attached to this surface. This latent image is developed with toner by a developing device d to form a toner image e, and then this toner image e is transferred onto paper g by a toner transfer corona discharger f, and This paper g
At the same time, this paper g is peeled off from the photoreceptor a by a corona discharger h for paper peeling, and the toner is fixed by a fixing device i to obtain a copy.

On the other hand, the photoreceptor a after the paper g is peeled off
is configured such that the charge is removed by a charge-eliminating corona discharger j as required, and the toner remaining on the surface thereof is removed by a cleaner k so that it can be reused.

In this way, the corona discharger charges the photoreceptor a,
It is used as a static eliminator, a toner image e transfer device, and a paper g peeling device.
As shown in Fig. 7, the structure generally consists of a shield l having a substantially U-shaped cross section and open on the photoreceptor side, and a discharge wire m stretched within the shield l and generating corona ions. In the corona discharger for charging, a grid n is attached to the open end side of the shield l as shown in FIG. 8, if necessary, so that the surface of the photoreceptor a can be uniformly charged. ing.

By the way, in this corona discharger, it is said that contaminants such as floating toner inside the copying machine and gas products caused by discharge easily adhere to the shield l, discharge wire m, grid n, etc., and as a result, the discharge function deteriorates. There were flaws.

That is, in a corona discharger equipped with grid n, as shown in FIG.
A large number of grids to which voltages of around 1000 volts are applied are installed at positions approximately mm apart, and this strong electric field causes floating toner, etc. to be transferred to the grids.
This is because they are easily adsorbed by.

The electric field of this grid n causes the photoreceptor a to
This equalizes the excess or deficiency of the potential of the photoreceptor a.
Since it has the function of forming a uniform copy image on the surface, if it becomes contaminated, the potential of that part increases and the electric field increases, so the potential of the photoreceptor a corresponding to that part increases, and this As a result, the problem was that the image density locally increased.

In addition, dust such as toner powder easily adheres to the discharge wire m, and products mainly composed of silicon also adhere to it due to the adsorption phenomenon accompanying corona discharge, so the amount of corona ions generated from the discharge wire m decreases. This had the disadvantage that the discharge function deteriorated.

Therefore, as shown in FIG.
A cleaning device p is disposed inside the cleaning device p, which is equipped with a cleaning pad o made of rubber, nonwoven fabric, etc., and this pad o is brought into pressure contact with the outer peripheral surface of the discharge wire m, etc. By sliding it along the discharge wire m, dirt such as toner powder adhering to the outer circumferential surface of the discharge wire m etc. is scraped off, thereby preventing the above-mentioned disadvantages.

[Problem that the invention seeks to solve]

However, in the corona discharger equipped with this cleaning device p, the dirt scraped off from the discharge wire m etc. during the cleaning operation falls onto the photoreceptor a, so this fallen dirt is left as is. In this case, there were drawbacks that caused various problems as shown below.

That is, the main component of the dirt is a developer such as toner, but since it has been altered by the discharge of the discharge wire m, it coagulates with each other to form large particles.

Therefore, if the dirt on the photoreceptor a is left as it is, the dirt will be transported into the developing device d when the copying process begins and the photoreceptor a rotates in the direction of arrow A. (see Figure 6), there was a drawback that clogging occurred in the developing device d, deteriorating the developing function.

Moreover, some of the dirt conveyed into the developing device d
It adheres to the photoreceptor a again during the developing process and forms the paper g.
If the dirt is transported onto the paper g, the dirt is easily transferred onto the paper g regardless of the electrostatic latent image on the photoreceptor a, since its charging characteristics are different from that of other normal developers. As a result, fogging and the like occur, resulting in a significant deterioration of copy image quality.

[Means and actions for solving problems]

The present invention has been made in view of the above circumstances, and is based on a corona discharger equipped with a cleaning device, and is designed to prevent dirt scraped from the discharge wire etc. during the cleaning operation from being conveyed into the developing device. It is an object of the present invention to provide a cleaning device for a corona discharger that does not deteriorate the developing function or the copied image.

That is, the present invention includes a photoconductor that rotates in a certain direction, a cleaner that is disposed near the photoconductor and that removes and cleans toner remaining on the surface of the photoconductor, and a cleaner that is disposed adjacent to the cleaner. , a corona discharger having a shield whose lower side is open and a discharge wire stretched therein to charge the surface of the photoreceptor cleaned by the cleaner; A cleaning member is installed in this shield to remove dirt such as toner adhering to the discharge wire and drop it onto the photoreceptor. The rotating direction of the photoreceptor is reversed and removed by the cleaner to prevent the dirt from being conveyed into the developing device, thereby preventing deterioration of the developing function and copy image quality.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.
As shown in the figure, a corona discharger 2 is disposed near a photosensitive drum 1 which is rotatable forward and backward by a motor (not shown), and a cleaning member ( (not shown)
, a cleaner 3 provided adjacent to the corona discharger 2 , and a reversing member (not shown) for reversing the direction of rotation of the photosensitive drum 1 .

First, as shown in FIG. 2, the corona discharger 2 includes a shield 4 made of conductive material with a substantially U-shaped cross section, wire attachment members 5 and 6 disposed on both ends of the shield 4, and the attachment members. A cleaning member consisting of a yoke 8 and a cleaning pad 9 attached to the yoke 8 is disposed within the shield 4. has been done. In FIG. 2, the front side surface of the shield 4 is omitted from illustration in order to facilitate understanding of the present invention.

As shown in FIGS. 2 and 3, the yoke 8 is formed on its upper surface side in a groove parallel to the width direction of the shield 4, and has a substantially U-shaped cross section into which the cleaning pad 9 is fitted. 10 and this groove 1
It is formed of a box-shaped insulator with substantially U-shaped cutout recesses 13 and 14 formed on the front wall 11 and rear wall 12 of 0, through which the corotron wire 7 is passed, A convex portion (not shown) provided on the bottom surface side is loosely fitted into a guide 15 provided on the bottom surface of the shield 4.

Further, a shaft 16 is attached to the lower side of the front wall 11 of this yoke 8, and is provided loosely through the wire attachment member 5.
By mechanically or manually sliding the yoke 8, the yoke 8 is moved along the length of the shield 4.

The cleaning pad 9 fitted to the yoke 8 is made up of two pieces of marinar material 17 and 18, as shown in FIG. and the cleaner material 17 with adhesive.
18 is attached so that it can slide along the wire 7 with a predetermined frictional force.

On the other hand, the cleaner 3 includes two fur brushes 19 and 20 disposed near the photosensitive drum 1, as shown in FIG.
a cylindrical conveying member 21 for conveying the residual toner removed by the conveying member 20; a fan 22 provided on the conveying member 21 and generating an air flow in the direction of the arrow; It consists of a cyclone filter 23 and a toner collection container 24 attached below the cyclone filter 23.

The photosensitive drum 1 is configured to be rotatable in the forward and reverse directions by a motor (not shown), and rotates in the direction of arrow A during the copying process.On the other hand, when operating the cleaning member of the corona discharger 2, the It is formed to rotate in the direction opposite to the direction A by the action of the reversing member that is not rotated.

In FIG. 1, 25 is an optical system, 26 is a developing device, and 2
7 indicates a fuser, and 28, 29 and 30
indicate corona dischargers for toner transfer, paper peeling, and static elimination, respectively.

To clean the corotron wire 7 of the corona discharger 2 using the cleaning device of the present invention, first slide the shaft 16 of the cleaning member to remove the yoke 8 from the corotron wire 7.
The cleaning pad 9 fitted on the yoke 8 scrapes off dirt adhering to the surface of the wire 7 and drops it onto the surface of the photosensitive drum 1.

Next, the reversing member is activated to rotate the photosensitive drum 1 in a direction opposite to the direction of arrow A to transport the dirt on the photosensitive drum 1 into the cleaner 3, and the cleaner 3 is activated to rotate the photosensitive drum 1 into the toner collection container. 24
The filth is discharged into the corotron wire 7 and the corotron wire 7 is cleaned.

Therefore, in the cleaning device of the present invention, dirt scraped from the surface of the corotron wire 7 is not carried into the developing device 26.
It is possible to prevent deterioration of the developing function of the developing device 26 and deterioration of copy image quality due to the dirt.

In the above embodiment, the cleaning member cleans only the corotron wire 7 inside the shield 4, but as shown in FIG. Notch recess 3 with approximately L-shaped cross section parallel to the horizontal direction
1 and 31 are formed and marinar materials 32 and 32 are interposed between the recesses 31 and 31 and the bottom surface of the shield 4, the bottom surface side of the shield can also be cleaned.

Further, the corona discharger of the above embodiment has a shield 4
Although this type of corona discharger does not have a grid on the open end side of the corona discharger, the present invention can also be applied to a corona discharger equipped with a grid.

That is, as shown in FIG. 5, the grid 33 is sandwiched between two pieces of cleaner material 34 and 35 from both sides, and the cleaner material 3 is attached with adhesive.
4 and 35 are glued together to form a cleaning pad 36, and this pad 36 is fitted into the groove 38 of the second yoke 37, which has an engaging recess (not shown) on the bottom side, and the second yoke 37 may be detachably attached to the yoke 8, which has an engagement protrusion (not shown) on the upper surface side that fits into the engagement recess.

Further, in the above embodiment, a cleaning pad is used as a cleaning member, but it may be replaced with a system using an ultrasonic vibrator.
Instead of the configuration using 9 and 20, other magnetic brush methods or blade methods may be adopted.
Its configuration is arbitrary.

Furthermore, the present invention can of course be applied not only to photosensitive drum type copying machines but also to photosensitive belt type copying machines.

〔Effect of the invention〕

As described above, the present invention provides a corona discharger that is disposed adjacent to a cleaner that removes and cleans toner remaining on the surface of a photoreceptor, in which dirt adhering to the discharge wire is removed within the shield. A cleaning member is provided to drop onto the photoreceptor, and the dirt is removed by the cleaner by reversing the direction of rotation of the photoreceptor, so that the dirt is not carried into the developing device. There is no.

Therefore, it has the effect of preventing deterioration of the developing function of the developing device and deterioration of copy image quality caused by the above-mentioned dirt.

[Brief explanation of drawings]

1 to 5 show embodiments of the present invention. FIG. 1 is an explanatory diagram of the configuration of a copying machine incorporating the cleaning device of the present invention, and FIG. 2 shows a corotron wire 7 inside a shield 4. FIG. 3 is a perspective view of the corona discharger according to the present invention in an installed state; FIG. 3 is a perspective view of the yoke 8 disposed within the shield 4 and fitted with the cleaning pad 9; FIG. 4 is a partial cross-sectional view of the yoke 8; FIG. 5 shows a perspective view of a cleaning member according to another embodiment, FIG. 6 is an explanatory diagram of the configuration of a conventional electrophotographic copying machine, and FIGS. 7 to 9 are perspective views of a conventional corona discharger. It is. Code explanation, 1... Photosensitive drum, 2, 28, 2
9,30...Corona discharger, 3...Cleaner,
4... Shield, 5, 6... Wire mounting member,
7...Corotron wire, 8,37...Yoke, 9,36...Cleaning pad, 10,3
8...Concave groove, 11...Front wall, 12...Rear wall, 1
3, 14, 31... recess, 15... guide, 16
...Shaft, 17, 18, 32, 34, 35...
...cleaner material, 19,20...fur brush,
21... Conveyance member, 22... Fan, 23... Cyclone filter, 24... Toner collection container,
25...optical system, 26...developing device, 27...fixing device, 33...grid.

Claims (1)

[Claims] 1. A photoconductor that rotates in a certain direction, a cleaner that is disposed near the photoconductor and cleans it by removing toner remaining on the surface of the photoconductor, and a cleaner that is disposed adjacent to the cleaner and whose lower side is In a copying machine equipped with a corona discharger having an open shield and a discharge wire stretched therein to charge the surface of the photoreceptor cleaned by the cleaner, the corona discharger includes the shield. A cleaning member is installed inside the discharge wire to remove dirt such as toner adhering to the photoreceptor and drop it onto the photoreceptor. A cleaning device for a corona discharger in a copying machine, characterized in that the cleaning device removes the corona discharger with the cleaner by reversing the direction of rotation.