JP2008170832A - Automatic cleaner for scorotron charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic cleaner for a scorotron charger, the cleaner being capable of surely cleaning a grid by preventing toner and so on scraped from the grid from adhering to the grid again. <P>SOLUTION: The automatic cleaner 6 for the scorotron charger 2 includes: a cleaning member that slides while pressing the grid of the scorotron charger 2, thereby cleaning the surface of the grid; a holding member that holds the cleaning member; a screw 7 that is inserted in the holding member so as to helically engage with it, thereby reciprocating the holding member in the lengthwise direction of the grid together with the cleaning member; and a drive motor 11 that normally and reversely rotates the screw 7. In the automatic cleaner 6 for the scorotron charger, a guide rib 14 is projectingly formed on the internal face of the screw insertion hole of the holding member, and the guide rib 14 is engaged with the screw 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an automatic cleaning device for automatically cleaning a grid and a charging wire of a scorotron charger.

  In an image forming apparatus such as a copying machine or a printer that employs an electrophotographic system, light corresponding to an image signal is irradiated onto a photosensitive drum whose surface is uniformly charged by a charger, and electrostatic latent images are formed on the photosensitive drum. An image is formed, and the electrostatic latent image is developed with toner by a developing device to be visualized as a toner image. The toner image is transferred from the photosensitive drum to a recording material such as paper by a transfer device, and the recording material onto which the toner image has been transferred is transported to a fixing device where the toner image is fixed by heat and pressure. After that, it is discharged out of the device.

  By the way, as a charger for uniformly charging the photosensitive drum, a scorotron charger is known in which a charging wire is stretched on a shield case and a grid is disposed along the charging wire. Since the charging ear and the grid of the charger are contaminated by the adhesion of the toner and the like as well as the durability, there arises a problem that the charging performance gradually decreases.

Therefore, the scorotron charger is equipped with an automatic cleaning device that automatically cleans the charging wire and the grid. This automatic cleaning device slides while pressing the grid of the scorotron charger. A cleaning member that cleans the surface of the grid, a holding member that holds the cleaning member, and a screw that reciprocates in the longitudinal direction of the grid together with the cleaning member by being screwed into the holding member and rotated. And an electric motor for rotating the screw forward and backward.
JP-A-4-254037 JP-A-4-016868

  However, in the conventional automatic cleaning apparatus, since the reciprocating cleaning member is constantly pressed against the surface of the grid, when the cleaning member that wipes off the toner from the surface of the grid is reversed and moves in the reverse direction, the cleaning member This causes a problem that the toner wiped off by the toner reattaches to the grid surface and the grid surface is not completely cleaned.

  Therefore, an object of the present invention is to provide an automatic cleaning device for a scorotron charger that can reliably clean the grid by preventing re-adhesion of toner or the like wiped off from the grid to the grid.

  The grid is easily deformed because it is made of a thin sheet metal having a thickness of about 0.1 mm. For this reason, it is necessary to keep the moving speed of the cleaning member sliding on the grid low. However, if the moving speed of the cleaning member is low, it takes a long time for cleaning and there is a problem that the waiting time of the user becomes long. .

  Accordingly, an object of the present invention is to provide an automatic cleaning device for a scorotron charger that can shorten the cleaning time by increasing the moving speed of the cleaning member.

  In order to achieve the above object, the invention according to claim 1 includes a cleaning member that cleans the surface of the grid by sliding while pressing the grid of the scorotron charger, a holding member that holds the cleaning member, In a scorotron charger automatic cleaning device having a screw that reciprocates in the longitudinal direction of the grid together with the cleaning member by screwing and inserting into the holding member and rotating, and a drive motor for rotating the screw forward and backward A guide rib projects from the inner periphery of the screw insertion hole of the holding member, and the guide rib is engaged with the screw.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the pitch of the central portion of the screw is made larger than the pitch of both end portions.

  According to the first aspect of the present invention, since the guide rib protruding from the inner periphery of the screw insertion hole of the holding member is engaged with the screw, the cleaning member is moved from the screw to the guide rib when the holding member moves in one direction. When the holding member reverses and moves in the other direction, a force that separates the cleaning member from the grid surface acts on the guide rib from the screw. Therefore, the toner on the grid surface is surely wiped off by the cleaning member that slides while being pressed against the grid surface, and when the cleaning member is reversed and moves in the reverse direction, the cleaning member is separated from the grid surface. The toner or the like wiped off by the cleaning member does not re-adhere to the grid surface, and the grid surface is completely cleaned and high charging performance is maintained in the scorotron charger.

  According to the invention described in claim 2, since the pitch of the central portion of the screw is made larger than the pitch of the both end portions, the cleaning is performed at the central portion excluding the both end portions of the screw at which the grid is easily damaged when starting and reversing the cleaning member. The moving speed of the member can be increased, and cleaning efficiency can be improved by shortening the cleaning time while preventing damage to the grid.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
1 is a perspective view of an automatic cleaning device according to Embodiment 1 of the present invention, FIG. 2 is a partial perspective view of the automatic cleaning device, and FIG. 3 is a partial perspective view showing the automatic cleaning device with a shield case of a charger removed. 4 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 5 is a perspective view of the holding member and the cleaning member of the automatic cleaning device, and FIG. 6 is a diagram illustrating the force acting on the guide rib from the screw when the screw rotates forward. FIG. 7 is an explanatory diagram for explaining the direction of the force acting on the guide rib from the screw when the screw rotates in the reverse direction.

  1 and 2, reference numeral 1 denotes a rotatable drum-shaped photosensitive drum, and a scorotron charger 2 for uniformly charging the outer surface of the photosensitive drum 1 to a predetermined potential is provided on the photosensitive drum 1. It is arranged along.

  The scorotron charger 2 has a charging wire 4 stretched between both ends in the longitudinal direction of a U-shaped shield case 3 whose lower surface facing the photosensitive drum 1 opens, and the lower surface opening of the shield case 3 It is configured by disposing a grid 5 made of a thin metal plate.

  The scorotron charger 2 is provided with an automatic cleaning device 6 for automatically cleaning the charging wire 4 and the grid 5. The automatic cleaning device 6 includes a screw 7 disposed above the scorotron charger 2 along the longitudinal direction of the shield case 3, and both axial ends of the screw 7 can be rotated by support members 8 and 9. It is supported. A gear 10 is attached to one end of the screw 7 that protrudes outward from the support member 9 as shown in FIG. 2. The gear 10 is attached to the output shaft of the drive motor 11. The pinion 12 is engaged.

  Further, a holding member 13 is screwed and inserted into the screw 7 so as to be movable along the screw 7, and a circular screw insertion hole 13a is formed above the holding member 13 as shown in FIG. Is penetrated. A guide rib 14 is partially protruded from the inner periphery of the screw insertion hole 13 a, and the guide rib 14 is engaged with the screw 7. Here, the axial length L of the guide rib 14 is set to be smaller than the helical pitch P of the screw 7 (see FIG. 2) (L <P), and the guide rib 14 is moved by the forward and reverse rotation of the screw 7. It engages alternately with the spiral of the screw 7 (see FIGS. 6 and 7).

  Further, as shown in FIG. 4, both sides of the holding member 13 sandwich the upper part of the shield case 3 of the scorotron charger 2 from both sides, thereby extending along the longitudinal direction of the shield case 3 (perpendicular to the plane of FIG. 4). A pair of left and right pad holding portions 13b accommodated in the shield case 3 are formed on the movable case. A pair of left and right pad holding members 13b hold a cleaning pad (not shown), and the cleaning pad holds the charging wire 4 from both sides. A cleaning member 15 for cleaning the surface of the grid 5 of the scorotron charger 2 is attached to the lower end surface of the holding member 13.

  By the way, the charging wire 4 and the grid 5 of the scorotron charger 2 are contaminated with toner and the like as they become more durable. Therefore, the charging wire 4 and the grid 5 are automatically cleaned by the automatic cleaning device 6.

  That is, when the drive motor 11 is driven, the rotation is transmitted to the screw 7 via the pinion 12 and the gear 10, and the screw 7 is rotationally driven. The holding member 13 inserted through the screw 7 is Since the guide rib 14 projecting from the inner periphery of the insertion hole 13a is engaged with the screw 7, the holding member 13 moves along the screw 7 and moves along with the holding member 13 and a cleaning pad (not shown) and cleaning. The member 15 cleans the charging wire 4 and the grid 5 of the scorotron charger 2 respectively.

  Here, when the screw 7 rotates forward in the direction of the arrow shown in FIG. 6, a vertical force F acts on the spiral surface of the screw 7 on the guide rib 14 that engages with the spiral of the screw 7. The holding member 13 and the cleaning member 15 held on the holding member 13 are moved in the direction of arrow a (leftward) in FIG. 6 by the component force F1 of F (= Fsin θ: θ is the spiral angle of the screw 7). At this time, since the downward force F2 (= Fcos θ) of the force F acts on the holding member 13 and the cleaning member 15, the cleaning member 15 is pressed against the grid 5, and the cleaning member 15 is pressed against the grid 5. By moving in the direction of arrow a in FIG. 6, the toner or the like attached to the surface of the grid 5 is wiped off.

  Thereafter, when the holding member 13 and the cleaning member 15 move to the end portion (home position) of the screw 7, the screw 7 is reversed in the direction of the arrow in FIG. A force F ′ in the vertical direction acts on the spiral surface of the screw 7 on the guide rib 14, and the holding member 13 and the cleaning member 15 held by the component F 1 ′ (= F′sin θ) of the force F ′ are illustrated in FIG. 7 moves in the direction of arrow b (right direction). At this time, since the upward component force F2 ′ (= F′cos θ) of the force F ′ acts on the holding member 13 and the cleaning member 15, the cleaning member 15 is separated from the grid 5, and thus separated from the grid 5. Even if the cleaned cleaning member 15 moves along the screw 7 in the direction of the arrow b, the toner or the like wiped off by the cleaning member 15 does not reattach to the surface of the grid 5, and the surface of the grid 5 is completely The scorotron charger 2 is cleaned and high charging performance is maintained.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG.

  FIG. 8 is a perspective view of an automatic cleaning device according to Embodiment 2 of the present invention. In FIG. 8, the same elements as those shown in FIG. Description of is omitted.

  The automatic cleaning device 6 according to the present embodiment is characterized in that the pitch P1 at the center of the screw 7 is larger than the pitch P2 at both ends (P1> P2), and other configurations are the same as those of the first embodiment. It is the same. In the present embodiment, the pitch of the screw 7 is set so as to gradually increase from both ends toward the center.

  Thus, in the automatic cleaning device 6 according to the present embodiment, the pitch P1 at the center of the screw 7 is larger than the pitch P2 at both ends, so that the grid 5 is damaged when the cleaning member 15 is started and reversed. The moving speed of the cleaning member 15 can be increased at the central portion excluding both ends of the easy screw 7, the cleaning time can be shortened while preventing the grid 5 from being damaged, and the user waits for higher cleaning efficiency. Time can be shortened.

It is a perspective view of the automatic cleaning apparatus which concerns on Embodiment 1 of this invention. It is a fragmentary perspective view of the automatic cleaning apparatus which concerns on Embodiment 1 of this invention. It is a fragmentary perspective view which removes the shield case of a charger and shows the automatic cleaning apparatus which concerns on Embodiment 1 of this invention. It is the sectional view on the AA line of FIG. It is a perspective view of a holding member and a cleaning member of an automatic cleaning device concerning Embodiment 1 of the present invention. It is explanatory drawing explaining the direction of the force which acts on a guide rib from this screw when a screw rotates forward. It is explanatory drawing explaining the direction of the force which acts on a guide rib from this screw when a screw reversely rotates. It is a perspective view of the automatic cleaning apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Scorotron charger 3 Shield case 4 Charging wire 5 Grid 6 Automatic cleaning device 7 Screw 8, 9 Support member 10 Gear 11 Drive motor 12 Pinion 13 Holding member 13a Screw insertion hole 13b Pad holding part 14 Guide rib 15 Cleaning member P, P1, P2 Screw pitch

Claims (2)

A cleaning member that cleans the surface of the grid by sliding while pressing the grid of the scorotron charger, a holding member that holds the cleaning member, and a holding member that is screwed into the holding member and rotated. In a scorotron charger automatic cleaning device having a screw that reciprocates in the longitudinal direction of the grid together with the cleaning member, and a drive motor that rotates the screw forward and backward,
An automatic cleaning device for a scorotron charger, characterized in that a guide rib projects from the inner periphery of the screw insertion hole of the holding member, and the guide rib is engaged with the screw.   2. The scorotron charger automatic cleaning device according to claim 1, wherein a pitch of a central portion of the screw is made larger than a pitch of both end portions.

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