JPH0455046U

JPH0455046U -

Info

Publication number: JPH0455046U
Application number: JP9691390U
Authority: JP
Priority date: 1990-09-14
Filing date: 1990-09-14
Publication date: 1992-05-12
Anticipated expiration: 2005-09-14
Also published as: JP2562567Y2

Description

[Brief explanation of the drawing]

第１図はマイナス電荷を帯電する定電流タイプ
のスコロトロンの等価回路図、第２図はスコロト
ロンの帯電特性を模式的に示す図、第３図はスコ
ロトロンを用いて放電電流を変化させた場合の感
光体表面の帯電電位分布の変化を示す図、第４図
は本考案のコロナ放電器の使用開始時の放電ムラ
防止装置の１実施例のシステム構成図、第５図か
ら第７図はその処理の手順を示すフローチヤート
、第８図はコロトロンとスコロトロンの断面を概
略的に示す図である。１……放電ワイヤ、２……シールド、３……グ
リツド、４……感光体、５……定電流源、６……
バリスタ又はツエナーダイオード、７……スイツ
チ、１０……スコロトロン、１１……除電ランプ
、１２……プラテン、１４……露光ランプ、１５
，１７……ミラー、１６……レンズ、１８……湿
度センサー、１９……現像器、２０……モータ、
２１……ランプ駆動回路、２２……高圧電源回路
、２３……モータ制御回路、２４……定着器、２
５……ＣＰＵ、２６……ＲＯＭ、２７……ＲＡＭ
、２８……タイマー。 Figure 1 is an equivalent circuit diagram of a constant current type scorotron that charges a negative charge, Figure 2 is a diagram schematically showing the charging characteristics of a scorotron, and Figure 3 is a diagram of the scorotron when the discharge current is varied. A diagram showing changes in the charged potential distribution on the surface of a photoreceptor, FIG. 4 is a system configuration diagram of one embodiment of the discharge unevenness prevention device at the start of use of the corona discharger of the present invention, and FIGS. 5 to 7 are the system configuration diagrams. FIG. 8 is a flowchart showing the processing procedure, and is a diagram schematically showing a cross section of a corotron and a scorotron. DESCRIPTION OF SYMBOLS 1... Discharge wire, 2... Shield, 3... Grid, 4... Photoreceptor, 5... Constant current source, 6...
Varistor or Zener diode, 7... Switch, 10... Scorotron, 11... Static elimination lamp, 12... Platen, 14... Exposure lamp, 15
, 17...Mirror, 16...Lens, 18...Humidity sensor, 19...Developer, 20...Motor,
21...Lamp drive circuit, 22...High voltage power supply circuit, 23...Motor control circuit, 24...Fuser, 2
5...CPU, 26...ROM, 27...RAM
, 28...timer.

Claims

[Scope of Claim for Utility Model Registration] (1) A corona discharger having a discharge wire is used to uniformly charge a photoreceptor that forms an electrostatic latent image, at the time of the start of use of a corona discharger in an image forming apparatus. A device for preventing discharge unevenness, comprising a means for applying a high voltage to a discharge wire of a corona discharger for a predetermined period of time to cause discharge before uniformly charging an object to be charged; 1. A discharge unevenness prevention device at the start of use of a corona discharger, characterized by comprising an antistatic means for preventing a charged body from being charged due to discharge. (2) The corona discharger according to claim 1, wherein a scorotron is used as the corona discharger, and the antistatic means is means for equalizing the potential of the grid of the scorotron to the potential of an uncharged photoreceptor. Device to prevent uneven discharge at the beginning of use. (3) The corona discharger according to claim 1 or 2, wherein the antistatic means comprises means for moving the photoreceptor relative to the corona discharger, and means for removing the charge on the photoreceptor. Device to prevent uneven discharge at the beginning of use. (4) The device for preventing discharge unevenness at the time of starting use of a corona discharger according to any one of claims 1 to 3, wherein the high voltage applied to the discharge wire for a predetermined period of time is an alternating current voltage. (5) uniformly charging the photoreceptor to form an electrostatic latent image using a scorotron with a discharge wire;
In a device for preventing discharge unevenness at the start of use of a scorotron in an image forming apparatus, one or both of the voltage and current applied to the discharge wire at the start of use and the voltage and/or current applied during normal image forming operation. means for increasing the number of images formed or the image forming operation time from the start of use, and a means for increasing the number of images formed or the image forming operation time from the start of use to a predetermined value, 1. A device for preventing discharge unevenness at the start of use of a corona discharger, comprising means for lowering one or both of applied voltage and current to a value during normal image forming operation. (6) The apparatus for preventing discharge unevenness at the start of use of a corona discharger according to any one of claims 1 to 5, further comprising a means for detecting humidity within the image forming apparatus, and wherein the detected humidity is within a predetermined level. An apparatus for preventing discharge unevenness at the start of use of a corona discharger, characterized in that the apparatus comprises means for operating each of the means only when the voltage exceeds a certain value.