JP3451001B2 - Corona charger - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a grid electrode plate of a corona charger such as an electrophotographic apparatus.

[0002]

2. Description of the Related Art Conventional corona discharge type chargers are roughly classified into a wire discharge type, a pin discharge type and a contact charging type.

The wire discharge method is classified into known corotron and discotron, and the wire discharge structure is such that a metal wire is stretched and charged by a corona generated by applying a DC high voltage. This type of configuration has low discharge efficiency, but the components are simple, inexpensive, and widely used. The pin discharge method is classified into the well-known pin electrode type and comb-teeth electrode type, and has been adopted in recent years, but the discharge efficiency is higher than that of the former, but the durability is poor and the frequency of replacement is high, and the components are complicated. Due to its unique shape, it was frequently cleaned. On the other hand,
In the contact charging method, there are rollers, belts, blades, particles, brushes, etc. as charging members, but the charging efficiency for the image carrier is high, but the toner remaining on the surface of the image carrier is in contact, Foreign matter such as paper dust was easily attached to the charging member, which promoted deterioration of image quality and was poor in durability. Further, although there is non-contact using a roller, it is difficult to control, the cost is high, and the cleaning of the roller is frequent.

Comparing the above methods, in particular, in a full-color electrophotographic apparatus which has recently been required in an office, a plurality of photoconductors are employed in the entire apparatus configuration, and high speed and highly reliable performance is inevitable. Since it is required, the parts configuration is simple, and the reliability is high and the maintenance frequency is low.
Chargers that use corona wires are often used because they are cheap.

[0005]

However, the charger using the above corona wire has the following problems.

In this type of charging method, a high DC voltage is applied to the wire to discharge it, but on the other hand, ozone and nitrogen oxides are generated along with the discharge, and the shield case and grid of the charger are contaminated. Further, since the corona wire itself collects fine substances such as toner that are floating around, such substances adhere to the wire. For these reasons, the charge potential rises, local discharge unevenness, etc. occur, which is a cause of image quality deterioration.

Therefore, it is necessary to carry out the cleaning whether the wire and the grid electrode plate are regularly operated automatically or manually.

For cleaning, there are a wet type using water or alcohol, and a dry type using rubbing a solid material. However, the wet type tends to have a complicated and large structure due to measures against drying, and automatic maintenance-free electrophotography. It was not suitable for the device.

It is an object of the present invention to solve the above problems and provide a dry cleaning method for a corona charger.

[0010]

In order to solve the above-mentioned problems, the present invention provides a grid electrode plate which is arranged close to the photosensitive drum in the longitudinal direction to charge the drum surface, and a wall surface which is erected from the grid electrode plate. In a corona charger equipped with
A frame that forms an opening in the longitudinal direction of the wall surface, covers the outside of the grid electrode plate and the wall surface, and engages with the opening; a spring plate that covers the inside of the grid electrode plate and the wall surface; A state in which abrasive paper is provided on a surface facing the grid electrode plate and cleaning means for removing foreign matter after the grid electrode plate is rubbed by the abrasive paper, and the abrasive paper is clamped and pressed by the frame and the spring plate. Then, a corona charger provided with a cleaning device that moves in the longitudinal direction along the opening is used.

[0011]

Further, the cleaning means and the rubbing means are integrally structured so that they can be attached to and detached from the corona charger. The rubbing means and the cleaning means are arranged in the non-charging portion in the longitudinal direction of the main body of the corona charger, and can be moved to the charging portion only in the rubbing and cleaning operations.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory view of a full color printer using a corona charger. Explaining according to the drawing, first, the internal structure of the full-color printer 1 includes a plurality of photosensitive drum units 2 and 3, and a plurality of developing devices 5 and 6 are arranged in the unit 2 as shown in the drawing, and an arrow 8 such as a laser is used. After being exposed by the exposure means, the toner is developed and transferred to the intermediate transfer body 9, and then the cleaning means 7 removes the residual toner. The same is done in unit 3. At this time, the developing devices 5 and 6 develop toners of four different colors, a full-color toner image is formed on the intermediate transfer body 9, and is discharged after being fixed by the fixing means 13 after being transferred onto the transfer paper by the transfer means 12. It

In the course of these processes, the corona charger 4 of the present invention applies a potential to the photosensitive drums 2A and 3A by the corona discharge action. Unit 2 and unit 3
Have the same configuration. In this charging method, a high DC voltage is applied to the wire to discharge it, but on the other hand, ozone and nitrogen oxides are generated along with the discharge, and the shield case and grid of the charger are contaminated. Also, the corona wire itself collects fine substances floating around, including toner, etc., and these substances adhere to the wire. For these reasons, the charge potential rises, the local discharge unevenness, etc. are caused, which causes the deterioration of the image quality. Therefore, a means for periodically cleaning the wires and the grid electrode plate is required.

2 to 5 illustrate the present invention for cleaning the grid electrode plate, and FIG. 2 is an explanatory view of the main parts of the corona charger.

The corona wire 201 is stretched between the wall surfaces 202 made of stainless steel, and the grid electrode plate 20 is provided below the corona wire 201.
3 is provided. On the wall surface 202, a cleaning device 205 for simultaneously cleaning the upper and lower surfaces of the grid electrode plate 203.
An opening 204 is provided in the longitudinal direction in order to detach and move the device in the longitudinal direction.

FIG. 3 is a schematic sectional view showing a state in which the cleaning device 205 is attached. The opening of the cleaning device 205 is controlled by the opening 20.
4 by engaging a part of the cleaning device 205 and sliding the cleaning device 205 in the longitudinal direction. The position of the cleaning device in the non-cleaning state is a position where it does not interfere with the charging of the photoconductors 2A and 3A, and a position other than the charging area A in FIG.

In FIG. 3, the cleaning device 205 includes a wall 2
The grid electrode plate 203 is press-contacted by inserting it into the opening 204 of No. 02 and attaching the resin frame 206 and the spring plate 207 having the polishing paper 208 on the surface. Abrasive paper 2
08 is a silicon carbide particle size No. 2000 (JISR
6253: CC2000), set to a pressure contact load of at least 5 to 10 g / mm ² with respect to the grid electrode plate 203, and after the grid electrode plate 203 is rubbed,
Foreign matters remaining on the surface layer of the grid electrode plate 203 are removed by a cleaning member 209 made of felt.

In this embodiment, the polishing paper 208 is provided so as to come into pressure contact with only the top surface of the grid electrode plate 203, but the top surface of the frame 206 is provided with the polishing paper 208.
3 The upper and lower surfaces may be polished at the same time, or only the lower surface may be polished.

Grid electrode plate 203 made of polishing paper 208
The power for rubbing may be manual, or may be automatic, that is, drive control by a motor or the like may be employed.

In the case of manual operation, if a rib that can be picked up by hand is provided on the wall surface of the frame 206, it can be easily operated. In the case of automatic, mechanically, a screw shaft is mechanically provided in the longitudinal direction near the wall surface of the frame 206, and a member guided by this screw shaft is attached to the wall surface, and the screw shaft is rotated for a certain time by electrical control. This is achieved by the guided member moving integrally with the cleaning device 205.

FIG. 4 is an explanatory view of the main parts in which the cleaning member 209 is installed at the end of the cleaning device 205.

The cleaning member 209 is attached to the cleaning device 2
05 may be attached to only one side in the longitudinal direction or may be attached to both ends. As the material of the cleaning member 209, in this embodiment, a polyethylene felt material formed into a pad shape is used. In another configuration, the cleaning device 205 has a simple configuration as shown in FIG. 5 when, for example, rubbing only the lower part of the grid electrode plate 203 for cleaning. That is, it is only necessary to fix the U-shaped frame 210 to the wall surface 211. The cleaning member 209 or the polishing paper 208 is attached between the grid electrode plate 203 and the frame 210.

[0025]

As described above, since the present invention can clean the grid electrode plate with a simple structure, it can be realized with a simple structure even in a cleaning device corresponding to a plurality of drums such as a color printer. It is very inexpensive and can be miniaturized. In addition, simplification of design, manufacturing and assembly has been realized,
In addition, man-hours can be reduced. In the unlikely event that parts are replaced at the time of maintenance, they can be quickly and simply executed. Further, according to this configuration, both manual and automatic can be applied, so that the degree of freedom in design is increased.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a full-color printer using a corona charger.

FIG. 2 is an explanatory view of a main part of the corona charger shown in FIG.

FIG. 3 is a schematic cross-sectional view showing a state in which a cleaning device 205 is attached.

FIG. 4 shows the cleaning member 20 at the end of the cleaning device 205.
The principal part explanatory view which installed 9.

FIG. 5 is a view showing a cleaning device on the lower surface side of the grid electrode.

[Explanation of symbols]

1 full color printer 2 Photosensitive drum unit 2A photoconductor drum 3 Photosensitive drum unit 3A photoconductor drum 4 Corona charger 5 Developer 6 developer 7 Cleaning means 8 Exposure means 9 Intermediate transfer body 201 corona wire 202 wall 203 grid electrode plate 204 opening 205 cleaning device 206 frames 207 spring plate 208 Polished paper 209 Cleaning member 210 frames 211 wall surface

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/02 H01T 19/00

Claims (3)

(57) [Claims] 1. A corona charger comprising: a grid electrode plate which is disposed close to the photosensitive drum in the longitudinal direction and charges the drum surface; and a wall surface provided upright from the grid electrode plate, wherein an opening is formed in the longitudinal direction of the wall surface. formed, said covering the outside of the grid electrode plate and wall surfaces, and opposed to the frame for engaging the opening, the grid electrode plate and a spring plate lining the walls, pre Kigu lid plate of the spring plate And a cleaning means for removing foreign matter after rubbing the grid electrode plate with the polishing paper on the surface to be treated,
A corona charger comprising a cleaning device arranged to move in a longitudinal direction along the opening in a state where the abrasive paper is clamped and pressed by the frame and the spring plate. 2. A corona charger according to claim 1 Symbol mounting, characterized in that the cleaning device has a detachable interchangeable configurable with respect to the corona charger. Wherein the cleaning device is disposed in the non-charging portion of the main body longitudinal direction of the corona charger, claim, characterized in that it is movable only in the charging unit in the case of rubbing and cleaning work 1
Serial corona charger of the placing.