Abstract: A corona discharge device used in an electrophotographic image forming apparatus includes a discharge member such as a saw-toothed discharge member having sharp discharge ends, and a power supply which applies to the discharge member a discharge voltage containing at least an AC voltage component, wherein at least each discharge end portion of the discharge member is made of an electrically conductive material, which contains nickel and chromium, and/or is coated with a material having a high electric resistance. In the case where the saw-toothed discharge member is employed, a distance D between the discharge end and a member to be charged, and a discharge end pitch P are determined to satisfy a relationship of 2≦D/P≦8.

Abstract: An image forming apparatus with a charging member that allows easy removal of smears from an image forming drum. The apparatus removes smears from the image forming drum by placing a different portion of the charging member in contact with the drum. The apparatus uses a cam or a solenoid to press on the charging member to cause a different portion of the charging member to come into contact with the image forming drum.

Abstract: Applied voltage to the contact charging sheet 71 has been controlled in the following various ways: a) the voltage at the photosensitive layer 10 at a point of time whereat it has passed the contact charging sheet 71 is caused to interlock with grid voltage so as not to exceed predetermined voltage to be electrified by the Scorotron charger 2; b) the applied voltage is caused to interlock with the output from the transfer unit 5 so that there is no portion which reaches the Scorotron charger 2 while the potential polarity has been reversed at the transfer unit 5; c) reduction in the film thickness of the photosensitive layer 10 is corrected in consideration of the cumulative number of sheets for image formation; d) the size of printing sheet is added; e) at the time of termination, a portion of the photosensitive layer 10, into which current has flowed at the transfer unit 5, is caused to stop always after passing the contact charging sheet 71; f) the contact charging sheet 71 is cleaned by means of AC compon

Abstract: A charging device K is provided with a flexible electrode 12 and a flexible intermediate member M disposed between the flexible electrode 12 and a charge-receiving member 10, with the flexible intermediate member M being in contact with the charge-receiving member 10. The flexible intermediate member M includes a flexible insulated member 11 and semiconductive member 14 so as to charge the charge-receiving member 10 via a discharge from electrode 12. The absolute value of the difference between the potential of the flexible electrode 12 during discharge and the potential in the vicinity of at least the area of discharge of the flexible electrode 12 among areas in which the flexible intermediate member is in contact with the charge-receiving member 10, is less than the absolute value of the difference between the potential of the charge-receiving member and the potential of the flexible electrode during discharge.

Abstract: This invention relates to the charging member portion of an image forming apparatus. A plurality of charging members are disclosed that maintain a uniform spacing between a charge-receiving member and the discharging portion of the charging members' electrodes despite surface irregularities and surface waviness on the charge-receiving member. One charging member is in the form of a flexible sheet provided with ventilation holes in a non-contacting portion thereof, permitting the air produced by the rotation of the charge-receiving member to escape through the holes to suppress the lifting of the charging member. Pressure fins can be added to the charging member on the downstream of the ventilation holes for further suppressing any lifting. Another charging member includes a semiconductive member or a electret member on at least the surface of the charging member on the side opposite the charge-receiving member. This permits the charging member to be electrostatically attracted to the charge-receiving member.

Abstract: An image forming apparatus having an electrostatic latent image carrier, and a charging device which includes an electric discharge electrode having a plurality of projection and a grid electrode located between the electric discharge electrode and the surface of the electrostatic latent image carrier. A grid electrode electric current Ig passing through the grid electrode and an image carrier electric current Ip passing through the conductive base of electrostatic latent image carrier satisfy the following relationship:1.5.ltoreq.Ig/Ip.ltoreq.4.

Abstract: An image forming apparatus, including a laminate image-bearing member having a dielectric layer or photoconductive layer, superimposed on an electrically conductive substrate, a transfer member for making pressure contact with said image-bearing member, and a cleaning member for cleaning the surface of said image-bearing member through contact therewith, forms an electrostatic latent image on said image-bearing member, develops said latent image into a visible toner image, and transfers said toner image from said image-bearing member to a transfer sheet passing through a contact-pressure nip portion between said image-bearing member and a transfer member by applying a controlled constant-current regulated transfer bias voltage to said transfer member.

Abstract: A charging device with a plate-like electrode having a plurality of protrusions, the charging device having a cleaning device including cleaning members which are positioned bilaterally to the electrode and grip the electrode therebetween to clean. The cleaning device cleans the electrode while the cleaning members slide on a guide formed along the electrode, or the cleaning device cleans the electrode by griping the electrode by the cleaning members which are positioned along the electrode.

Abstract: Grid wires arranged in an axial direction of a photoconductive drum have a positional relation with projecting electrodes arranged at regular intervals in an axial direction of the photoconductive drum at a position opposite to the surface of the photoconductive drum wherein the grid wires and the projecting electrodes positioned adjacent to each other are equally arranged in distance to uniformly discharge an electric charge to the surface of the photoconductive drum from each of the projecting electrodes so that uniform charging can be accomplished in an axial direction of the photoconductive drum.

Abstract: An acoustic-emission sensor includes a composite synthetic resin-ceramic piezoelectric element which has a plurality of substantially mutually parallel columnar ceramic piezoelectric bodies. The columnar ceramic piezoelectric bodies are polarized in a longitudinal direction and are disposed in a synthetic-resin matrix. Since only longitudinal waves can be detected from among acoustic-emission waves, an intensity and variation in intensity can be detected accurately.