JPH04133258U - Scorotron type charger - Google Patents

Abstract

(57) [Abstract] [Purpose] In a scorotron charger that charges a photoreceptor, the variation in the distance between the photoreceptor surface and the grid plate can be minimized without being affected by the eccentricity of the photoreceptor drive shaft. The purpose is to minimize fluctuations in potential on the surface of the photoreceptor and provide stable images. [Structure] A grid plate 21 is attached by hooks 22 and 23, and tension is applied to the grid plate 21 in the longitudinal direction by a coil spring 24 disposed between the hook 23 and the holder 11. Positioning members 26 and 27 made of an insulating material are provided between the grid plate 21 and the photoreceptor 3.
is installed. When the positioning members 26 and 27 are not provided, the grid plate 21 has the positioning members 26 and 27
They are located close to the surface of the photoreceptor 3 at an interval narrower than the height of the photoreceptor 3. Therefore, when the positioning members 26 and 27 are provided, the grid plate 21
The distance between the grid plate 21 and the surface of the photoreceptor 3 is set to a predetermined distance (=positioning members 26, 27) by the positioning members 26, 27.
height).

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention applies an electric charge to the photoreceptor in electrophotographic copiers, printers, etc. Regarding a scorotron type charger that generates electricity.

0002

[Conventional technology]

Traditionally, scorotron chargers have a grid plate in addition to the charge wire. is widely known.

0003 In copying machines that use electrophotography, the setting of the surface potential of the photoreceptor is This is an important quality item, and fluctuations in surface potential have a negative impact on image quality (background fog, camera (rear adhesion, etc.). Such fluctuations in surface potential are caused by scorotron chargers. depends on the distance between the photoreceptor and the grid plate. regarding this , the applicant has determined that the distance between the photoreceptor surface and the grid plate is ±0.2 m, as shown in FIG. Make sure that the surface potential of the photoconductor changes by about ±20 to 25 V if it fluctuates by about m. I agree.

0004 As a technique for solving the above-mentioned inconveniences, Japanese Utility Model Application Publication No. 58-168743 In this case, a grid plate holding member is provided on the drive shaft of the photoconductor, and the grid plate is held between the photoconductor surface and the grid plate. Scoroto is configured to keep the surface potential of the photoreceptor constant by maintaining a predetermined distance between A Ron type charger is disclosed.

[0005]

[Problem that the idea aims to solve]

However, in the technique disclosed in the above-mentioned Japanese Utility Model Publication No. 58-168743, the drive shaft of the photoreceptor Since the grid plate holding member is provided on the top, the machining accuracy of the grid plate holding member is improved. Even if the The fluctuation of the surface potential did not disappear.

[0006] The present invention is able to maintain contact with the surface of the photoconductor without being affected by the amount of eccentricity of the drive shaft of the photoconductor. By minimizing fluctuations in the distance between lid plates, fluctuations in the potential on the photoreceptor surface can be reduced. Obtaining a scorotron type charger to minimize and provide stable images With the goal.

[0007]

[Means to solve the problem]

In view of the above-mentioned problems, the present invention is based on a scorotron type that charges the photoreceptor. In a charger, a grip is used to hold the grid plate and apply tension in the longitudinal direction of the grid plate. The lid plate holding member slides on the photoreceptor surface and maintains a predetermined distance between the photoreceptor surface and the grid plate. and a positioning member for keeping them separated.

[0008]

[Effect]

In the present invention, positioning is performed to maintain a predetermined distance between the grid plate and the photoreceptor. A member is provided between the grid plate and the photoreceptor. The grid plate is While being held by the holding member, tension is applied in the longitudinal direction, so that it is always strongly tensioned. ing. When the positioning member is not installed, the grid plate is at the height of the positioning member. They are located close to the surface of the photoreceptor at narrower intervals. Therefore, positioning When a positioning member is provided, the grid plate attaches the positioning member toward the surface of the photoreceptor. However, the distance between the grid plate and the photoreceptor surface is set to a predetermined distance by the positioning member. They are kept at a distance (= height of the positioning member).

[0009]

【Example】

The present invention will be described below with reference to the drawings.

0010 Figure 1 shows an outline of an electrophotographic printer using the scorotron charger of the present invention. FIG. The main components of this electrophotographic printer are the charging charger 2, PC cartridge 1 with built-in photoreceptor drum 3, developer 4, etc., polygon mirror -, a laser optical system 5 consisting of an fθ lens, etc., a transfer charger 6, etc. It is. The image forming process of an electrophotographic printer is well known and will therefore be omitted.

[0011] FIG. 2 is a front sectional view of the vicinity of the charger 2 of the PC cartridge 1. Charger 2 The support part is composed of holders 10, 11 and a stabilizing plate 12, and its right end is connected to a leaf spring 13. , its left end is positioned on the PC cartridge 1 by a set screw 14. The left end of the charge wire 15 is fixed to a hook 16 provided on the holder 10. The right end is placed in the holder 11 with tension applied through the coil spring 17. It is fastened to a support pin 18 that has been cut out. Also, the position of the charge wire 15 is It is determined by the charge wire support part 19. The hook 16 is attached to a belt (not shown). It is attached to the holder 10 by a contact screw 20 connected to an electric power source. , so that a voltage is applied to the charge wire 15 via the contact screw 20. It has become.

0012 Next, the grid plate 21 is attached with hooks 22 and 23, and the grid plate 21 is attached with hooks 22 and 23. A coil spring 24 disposed between the hook 23 and the holder 11 is connected to the head plate 21. Thus, tension is applied to the grid plate 21 in the longitudinal direction. In addition, the hook 22 is The contact coil spring 25 to which the power supply for applying the grid is connected is pressure-welded. A voltage is applied to the grid plate 21 via this contact coil spring 25.

[0013] A positioning member made of an insulating material is provided between the grid plate 21 and the photoreceptor 3. 26 and 27 are arranged, and the distance between the photoreceptor 3 and the grid plate 21 is determined by its position. It is kept constant by retaining members 26 and 27. These positioning members 26 and 27 are photosensitive. Although it is in sliding contact with the non-photosensitive layer portion 28 of the body 3, the shape of the sliding contact portion of the positioning members 26 and 27 is The shape is semicircular, and the sliding contact area is coated with a low-friction material such as Teflon. This may adversely affect the image formed on the photoreceptor 3 and the rotation of the photoreceptor 3. I don't have to worry about giving it away. In addition, when applying Teflon etc. to the positioning members 26 and 27, Furthermore, the positioning member itself may be made of an insulating and low-friction material.

[0014] 3 and 4 are a cross-sectional view of the charger 2 and an enlarged view of the positioning member of the charger 2, respectively. FIG. As shown in the figure, the positioning member 26 is provided with an elongated hole 29, and The PC cartridge side includes a relief part 30 when the positioning member 26 moves up and down. A support boss 31 corresponding to the elongated hole 29 is provided in the center of the recess. It stands out. The positioning of the grid plate 21 with respect to the photoreceptor 3 is performed using the positioning member 2. Since it is set slightly closer to the photoconductor side than the thickness of 6, the coil spring The grid plate 21 always presses the positioning member 26 against the photoreceptor 3 due to the biasing force 24. Ru. As a result, even if there is eccentricity in the drive shaft of the photoconductor 3, the position can be determined according to the amount of eccentricity. Since the holding member 26 moves up and down, the photoreceptor 3 and the grip are not affected by eccentricity of the drive shaft. The distance from the head plate 21 can be maintained at a constant distance. Regarding the positioning member 27, They have the same configuration.

[0015]

【effect】

In this invention, in the scorotron type charger that charges the photoreceptor, the above-mentioned By adopting a configuration like this, it is not affected by the eccentricity of the drive shaft of the photoreceptor, Since the distance between the photoconductor and the grid plate can be maintained at a specified distance, the potential on the photoconductor surface can be reduced. fluctuations can be minimized and stable images can be provided.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an electrophotographic printer using a scorotron charger according to the present invention.

FIG. 2 is a front sectional view of the PC cartridge.

FIG. 3 is a sectional view of the scorotron charger of the present invention.

FIG. 4 is a perspective view of the charging section of the scorotron charger of the present invention.

FIG. 5 is a diagram showing variations in the surface potential of a photoconductor due to variations in the distance between the photoconductor and a grid plate in a scorotron charger.

[Explanation of symbols]

2 Scorotron type charger 3 Photoreceptor 21 Grid board 22, 23 hook 24 Coil spring 26, 27 Positioning member

Claims (1)

[Scope of utility model registration request] Claim 1: A scorotron charger for charging a photoreceptor, comprising: a grid plate holding member that holds a grid plate and applies tension in the longitudinal direction of the grid plate; and a grid plate holding member that is in sliding contact with the photoreceptor surface. A scorotron charger comprising: a positioning member that maintains a predetermined distance between grid plates.