Abstract: A charging member includes a conductive elastic layer, and a conductive surface layer that is disposed on the conductive elastic layer, is in contact with an image holding member, and contains a resin, porous resin particles, and silicone oil, wherein a content of the porous resin particles is from 3 parts by weight to 25 parts by weight based on 100 parts by weight of the resin, and a content of the silicone oil is from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of the resin.

Abstract: An image forming apparatus includes a charging roller including elastic and surface layers and a photoconductor drum. Initially, the surface layer has a surface roughness Rz of 3-6 ?m, and the layers have an impedance ratio of 0.81 or less in absolute value at a frequency of 800-3000 Hz. After a predetermined time, the surface roughness Rz is reduced by a decrement ?Rz of 0.1-4 ?m. The drum has a film thickness D initially ranging from 20-40 ?m and reduced by a decrement ?D of 5-25 ?m after the predetermined time. Herein, 0.005??Rz/?D?0.8 holds. The impedance ratio is represented as ZE/(ZE+ZS) wherein ZE and ZS represent the respective impedances of the elastic layer and the surface layer, and 100k A4-size recording media recorded with images with an area coverage of 7% are printed in the predetermined time.

Abstract: A charging member includes a conductive elastic layer, and a conductive surface layer that is disposed on the conductive elastic layer, is in contact with an image holding member, and contains a resin, porous resin particles, and silicone oil, wherein a content of the porous resin particles is from 3 parts by weight to 25 parts by weight based on 100 parts by weight of the resin, and a content of the silicone oil is from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of the resin.

Abstract: An image forming apparatus includes a charging roller including elastic and surface layers and a photoconductor drum. Initially, the surface layer has a surface roughness Rz of 3-6 ?m, and the layers have an impedance ratio of 0.81 or less in absolute value at a frequency of 800-3000 Hz. After a predetermined time, the surface roughness Rz is reduced by a decrement ?Rz of 0.1-4 ?m. The drum has a film thickness D initially ranging from 20-40 ?m and reduced by a decrement ?D of 5-25 ?m after the predetermined time. Herein, 0.005??Rz/?D?0.8 holds. The impedance ratio is represented as ZE/(ZE+ZS) wherein ZE and ZS represent the respective impedances of the elastic layer and the surface layer, and 100 k A4-size recording media recorded with images with an area coverage of 7% are printed in the predetermined time.

Abstract: A charging roller includes a conductive core, a resistive elastic layer disposed on the conductive core, and a surface layer disposed on the resistive elastic layer. The impedances of the resistive elastic layer and the surface layer measured at an environmental temperature of about 10° C. and a humidity of about 15% RH in a range of alternating voltage frequencies of an image-forming apparatus used satisfy: |ZE/(ZE+ZS)|?0.81 where ZE is the impedance of the resistive elastic layer, and ZS is the impedance of the surface layer.

Abstract: The present invention provides a cleaning member for an image forming apparatus, including: an axle; and a belt-like elastic medium that is wound on the outer circumferential surface of the axle in a spiral shape and that includes a first edge portion in at least one of both ends in the width direction thereof and a second edge portion coming in contact with a surface to be cleaned at an angle different from that of the first edge portion.

Abstract: A charging device includes: a charging member that faces an image carrier and charges a surface of the image carrier; a charging voltage controller that controls a charging voltage to be applied to the charging member when the surface of the image carrier is to be charged, and applies the charging voltage obtained by superposing an AC voltage which is subjected to constant-current control on a DC voltage; a variation range detector that detects a variation range of the AC voltage which changes according to the characteristic change of the charging member; and a response speed controller that reduces a response speed for the variation of the AC voltage in correspondence with the characteristic change when the variation range is larger than a predetermined set value.

Abstract: A charging device includes: a charging member; a charging power source that applies a charging voltage to the charging member; a temperature dependence storage unit that stores preset temperature dependence; a humidity dependence storage unit that stores preset humidity dependence; an ambient temperature detecting unit that detects an ambient temperature in the vicinity of the charging member; an ambient humidity detecting unit that detects an ambient humidity in the vicinity of the charging member; and a charging voltage control unit that applies the charging voltage to the charging member according to (i) a constant current value that is determined according to the temperature dependence as corresponding to the detected ambient temperature or (ii) a constant current value that is determined according to the humidity dependence as corresponding to the detected ambient temperature and the detected ambient humidity.

Abstract: The present invention provides a cleaning member for an image forming apparatus, including: an axle; and a belt-like elastic medium that is wound on the outer circumferential surface of the axle in a spiral shape and that includes a first edge portion in at least one of both ends in the width direction thereof and a second edge portion coming in contact with a surface to be cleaned at an angle different from that of the first edge portion.

Abstract: A charging device includes: a charging member that faces an image carrier and charges a surface of the image carrier; a charging voltage controller that controls a charging voltage to be applied to the charging member when the surface of the image carrier is to be charged, and applies the charging voltage obtained by superposing an AC voltage which is subjected to constant-current control on a DC voltage; a variation range detector that detects a variation range of the AC voltage which changes according to the characteristic change of the charging member; and a response speed controller that reduces a response speed for the variation of the AC voltage in correspondence with the characteristic change when the variation range is larger than a predetermined set value.

Abstract: A charging device includes: a charging member; a charging power source that applies a charging voltage to the charging member; a temperature dependence storage unit that stores preset temperature dependence; a humidity dependence storage unit that stores preset humidity dependence; an ambient temperature detecting unit that detects an ambient temperature in the vicinity of the charging member; an ambient humidity detecting unit that detects an ambient humidity in the vicinity of the charging member; and a charging voltage control unit that applies the charging voltage to the charging member according to (i) a constant current value that is determined according to the temperature dependence as corresponding to the detected ambient temperature or (ii) a constant current value that is determined according to the humidity dependence as corresponding to the detected ambient temperature and the detected ambient humidity.

Abstract: An image formation apparatus includes: a photoconductor that has a photoconductive layer having a surface on which an electrostatic latent image is formed; a charging roll to which a bias with an AC component superposed on a DC component is applied for charging the photoconductor at a predetermined potential; a film thickness detector that detects a film thickness of the photoconductive layer of the photoconductor without applying the AC component; an environment measuring section that measures at least one of ambient temperature and humidity; an AC component setting section that sets a value of the AC component of the bias based on detection results of the film thickness detector and the environment measuring section; and a charging controller that controls at least one of voltage and current applied to the charging roll based on the value of the AC component set by the AC component setting section.

Abstract: A charging device includes a charging member disposed so as to rotate in contact with a surface of an image carrier to charge the image carrier surface, a bias voltage applying unit that applies a bias voltage to the charging member, the bias voltage having an AC voltage superimposed on a DC voltage, a DC current detector that detects a DC current flowing between the image carrier and the charging member, a filter that extracts only a specific component from the DC current detected by the DC current detector, and a controller that controls at least one of an AC voltage and an AC current to be applied to the charging member in accordance with an amount of variation of the specific component extracted from the DC current by the filter.

Abstract: A charging device includes a charging member that charges a body to be charged; a detector that detects an AC component of a current flowing through the charging member; an integration section that integrates the AC component of the current detected by the detector; a controller that controls the current flowing through the charging member, according to a result of integration executed by the integration section; a periodic signal generating section that generates a periodic signal having a cycle period corresponding to a cycle period of the AC component; and an integration period adjusting section that adjusts a period of integration executed by the integration section, with reference to the periodic signal.

Abstract: An image forming apparatus includes a photoreceptor having on a surface thereof a photosensitive layer, in which an electrostatic latent image is formed, a contact charging roll applied with a bias containing a direct current component having superimposed thereon an alternating current component, the contact charging roll charging the photoreceptor to a predetermined potential, a film thickness detecting unit detecting a film thickness of the photosensitive layer of the photoreceptor, an environment detecting unit detecting environment, and a contact area changing unit changing a contact area between the contact charging roll and the photoreceptor based on detected results of the film thickness detecting unit and the environment detecting unit.

Abstract: A charging device includes a charging member that charges a body to be charged; a detector that detects an AC component of a current flowing through the charging member; an integration section that integrates the AC component of the current detected by the detector; a controller that controls the current flowing through the charging member, according to a result of integration executed by the integration section; a periodic signal generating section that generates a periodic signal having a cycle period corresponding to a cycle period of the AC component; and an integration period adjusting section that adjusts a period of integration executed by the integration section, with reference to the periodic signal.

Abstract: A charging device includes a charging member disposed so as to rotate in contact with a surface of an image carrier to charge the image carrier surface, a bias voltage applying unit that applies a bias voltage to the charging member, the bias voltage having an AC voltage superimposed on a DC voltage, a DC current detector that detects a DC current flowing between the image carrier and the charging member, a filter that extracts only a specific component from the DC current detected by the DC current detector, and a controller that controls at least one of an AC voltage and an AC current to be applied to the charging member in accordance with an amount of variation of the specific component extracted from the DC current by the filter.

Abstract: An image formation apparatus includes: a photoconductor that has a photoconductive layer having a surface on which an electrostatic latent image is formed; a charging roll to which a bias with an AC component superposed on a DC component is applied for charging the photoconductor at a predetermined potential; a film thickness detector that detects a film thickness of the photoconductive layer of the photoconductor without applying the AC component; an environment measuring section that measures at least one of ambient temperature and humidity; an AC component setting section that sets a value of the AC component of the bias based on detection results of the film thickness detector and the environment measuring section; and a charging controller that controls at least one of voltage and current applied to the charging roll based on the value of the AC component set by the AC component setting section.

Abstract: An image forming apparatus includes a photoreceptor having on a surface thereof a photosensitive layer, in which an electrostatic latent image is formed, a contact charging roll applied with a bias containing a direct current component having superimposed thereon an alternating current component, the contact charging roll charging the photoreceptor to a predetermined potential, a film thickness detecting unit detecting a film thickness of the photosensitive layer of the photoreceptor, an environment detecting unit detecting environment, and a contact area changing unit changing a contact area between the contact charging roll and the photoreceptor based on detected results of the film thickness detecting unit and the environment detecting unit.