Abstract: An image forming apparatus includes a photosensitive member unit, a charging member, an exposing unit, a developing unit, an information storage portion, and a setting portion. The information storage portion stores information on an attenuation amount of a surface potential of the photosensitive member by which the surface potential is attenuating until the photosensitive member rotates from a contact position of the photosensitive member to a development position of the photosensitive member. If the attenuation amount is a first attenuation amount, the setting portion sets an applying voltage to be applied to the charging member at the time of image formation to a first voltage. If the attenuation amount is a second attenuation amount greater than the first attenuation amount, the setting portion sets an applying voltage to be applied to the charging member at the time of image formation to a second voltage higher than the first voltage.

Abstract: An image forming apparatus includes a photosensitive member unit, a charging member, an exposing unit, a developing unit, an information storage portion, and a setting portion. The information storage portion stores information on an attenuation amount of a surface potential of the photosensitive member by which the surface potential is attenuating until the photosensitive member rotates from a contact position of the photosensitive member to a development position of the photosensitive member. If the attenuation amount is a first attenuation amount, the setting portion sets an applying voltage to be applied to the charging member at the time of image formation to a first voltage. If the attenuation amount is a second attenuation amount larger than the first attenuation amount, the setting portion sets an applying voltage to be applied to the charging member at the time of image formation to a second voltage larger than the first voltage.

Abstract: An image forming apparatus includes an image bearing member, a charging member, an exposing device, a developing device, a transfer member, and a rubbing member. The image bearing member includes a plurality of recess portions on a surface thereof. The rubbing member is configured to come into contact with the image bearing member to form a rubbing nip portion between the rubbing member and the image bearing member. The recess portions each have an opening portion whose maximum length in the rotational direction is 20 ?m to 120 ?m. When a linear speed of the image bearing member in the rubbing nip portion is S1 and a linear speed of the rubbing member in the same direction as the linear speed of the image bearing member in the rubbing nip portion is S2, a relationship of a linear speed ratio of S2/S1<1.0 is satisfied.

Abstract: An image forming apparatus includes an image bearing member, a charging member, an exposing device, a developing device, a transfer member, and a rubbing member. The image bearing member includes a plurality of recess portions on a surface thereof The rubbing member is configured to come into contact with the image bearing member to form a rubbing nip portion between the rubbing member and the image bearing member. The recess portions each have an opening portion whose maximum length in the rotational direction is 20 ?m to 120 ?m. When a linear speed of the image bearing member in the rubbing nip portion is S1 and a linear speed of the rubbing member in the same direction as the linear speed of the image bearing member in the rubbing nip portion is S2, a relationship of a linear speed ratio of S2/S1<1.0 is satisfied.

Abstract: A control unit performs control to satisfy TVa<T TVb, where T is a time from a point when irradiation with light by a pre-exposure member is started to a point when a predetermined portion of the photosensitive member which is located at the pre-exposure position when the irradiation is started reaches a charging position, TVa is a time from the point when the irradiation is started to a point when application of a first voltage is started, and TVb is a time from the point when the irradiation is started to a point when application of the second voltage is started.

Abstract: A control unit performs control to satisfy TVa<T TVb, where T is a time from a point when irradiation with light by a pre-exposure member is started to a point when a predetermined portion of the photosensitive member which is located at the pre-exposure position when the irradiation is started reaches a charging position, TVa is a time from the point when the irradiation is started to a point when application of a first voltage is started, and TVb is a time from the point when the irradiation is started to a point when application of the second voltage is started.

Abstract: An image forming apparatus includes a photosensitive member, a charging member, an exposure member, a rotatable developer carrying member, a voltage source, and a controller configured to control the voltage source so that when a thickness of the surface layer of the photosensitive member is a first thickness, a developing bias voltage including an oscillating portion having an oscillating voltage and a rest portion having a substantially constant voltage alternately repeated is outputted. When the thickness of the surface layer of the photosensitive member is a second thickness smaller than the first thickness, a developing bias voltage in which the rest portion is not included or is shorter than the rest portion when the thickness of the surface layer is the first thickness is outputted.

Abstract: An image forming apparatus includes an image-bearing member, which is charged by a charge voltage in which direct and alternating-current voltages are superposed on each other. A toner image is formed on the charged image-bearing member. A current flowing through the charging member is detected when the charge voltage is applied to the charging member. A current, in a frequency band including a discharge current component, is extracted from the detected current. The alternating-current voltage is adjusted based on the current extracted by an extraction unit. Environmental information is acquired. Based on the environmental information acquired by an acquisition unit, a frequency band for extraction performed by the extraction unit is set.

Abstract: An image forming apparatus includes a photosensitive member, a charging member, an exposure member, a rotatable developer carrying member, a voltage source, and a controller configured to control the voltage source so that when a thickness of the surface layer of the photosensitive member is a first thickness, a developing bias voltage including an oscillating portion having an oscillating voltage and a rest portion having a substantially constant voltage are alternately repeated is outputted and so that when the thickness of the surface layer of the photosensitive member is a second thickness smaller than the first thickness, a developing bias voltage in which the rest portion is not included or is shorter than the rest portion when the thickness of the surface layer is the first thickness.

Abstract: An image forming apparatus includes a photosensitive member, a charging member, an exposure member, a rotatable developer carrying member, a voltage source, and a controller configured to control the voltage source so that when a humidity of an inside of the apparatus is a first humidity, a developing bias voltage including an oscillating portion having an oscillating voltage and a rest portion having a substantially constant voltage are alternately repeated is outputted and so that when the humidity of the inside of the apparatus is a second humidity lower than the first humidity, a developing bias voltage in which the rest portion is not included or is shorter than the rest portion when the humidity of the inside of the apparatus is the first humidity.

Abstract: An image forming apparatus includes an image-bearing member, which is charged by a charge voltage in which direct and alternating-current voltages are superposed on each other. A toner image is formed on the charged image-bearing member. A current flowing through the charging member is detected when the charge voltage is applied to the charging member. A current, in a frequency band including a discharge current component, is extracted from the detected current. The alternating-current voltage is adjusted based on the current extracted by an extraction unit. Environmental information is acquired. Based on the environmental information acquired by an acquisition unit, a frequency band for extraction performed by the extraction unit is set.

Abstract: An image forming apparatus includes an image-bearing member, which is charged by a charge voltage in which direct and alternating-current voltages are superposed on each other. A toner image is formed on the charged image-bearing member. A current flowing through the charging member is detected when the charge voltage is applied to the charging member. A current, in a frequency band including a discharge current component, is extracted from the detected current. The alternating-current voltage is adjusted based on the current extracted by an extraction unit. Environmental information is acquired. Based on the environmental information acquired by an acquisition unit, a frequency band for extraction performed by the extraction unit is set.

Abstract: An image forming apparatus includes an image-bearing member, which is charged by a charge voltage in which direct and alternating-current voltages are superposed on each other. A toner image is formed on the charged image-bearing member. A current flowing through the charging member is detected when the charge voltage is applied to the charging member. A current, in a frequency band including a discharge current component, is extracted from the detected current. The alternating-current voltage is adjusted based on the current extracted by an extraction unit. Environmental information is acquired. Based on the environmental information acquired by an acquisition unit, a frequency band for extraction performed by the extraction unit is set.

Abstract: A charging device includes a corona charger, provided with an opening opposing a photosensitive member, for electrically charging the photosensitive member; a sheet-like member provided so that the sheet-like member can cover the opening; a movable device for moving the sheet-like member; and a regulating device for regulating a shape of the sheet-like member so that a central portion of the sheet-like member protrudes toward the corona charger with respect to a circumferential direction of the photosensitive member.

Abstract: A charging device includes a corona charger, provided with an opening opposing a photosensitive member, for electrically charging the photosensitive member; a sheet-like member provided so that the sheet-like member can cover the opening; a movable device for moving the sheet-like member; and a regulating device for regulating a shape of the sheet-like member so that a central portion of the sheet-like member protrudes toward the corona charger with respect to a circumferential direction of the photosensitive member.

Abstract: A charging device includes a corona charger, provided with an opening opposing a photosensitive member, for electrically charging the photosensitive member; a sheet-like member provided so that the sheet-like member can cover the opening; a movable device for moving the sheet-like member; and a regulating device for regulating a shape of the sheet-like member so that a central portion of the sheet-like member protrudes toward the corona charger with respect to a circumferential direction of the photosensitive member.

Abstract: A charging device includes a corona charger, provided with an opening opposing a photosensitive member, for electrically charging the photosensitive member; a sheet-like member provided so that the sheet-like member can cover the opening; a movable device for moving the sheet-like member; and a regulating device for regulating a shape of the sheet-like member so that a central portion of the sheet-like member protrudes toward the corona charger with respect to a circumferential direction of the photosensitive member.

Abstract: The present invention provides a charging device which can suppress the deterioration of a photosensitive member and the occurrence of an image deletion phenomenon on an electrophotographic image due to an electric discharge product having deposited on a charger shutter, even when having been used for a long period of time. The charging device has an image bearing member which bears an image thereon, a charging member which charges the image bearing member, and a shielding member which shields the charging member from the image bearing member, wherein the shielding member includes a specific material.

Abstract: A charging device includes a corona charger for electrically charging a photosensitive member; a sheet-like member for covering and uncovering an opening of the corona charger; a regulating member for regulating a shape of the sheet-like member so that the sheet-like member is convex toward the corona charger with respect to a circumferential direction of the photosensitive member; and a winding-up member, including a winding-up shaft around which the sheet-like member is to be wound up, for winding up the sheet-like member so that a surface of the sheet-like member opposing the corona charger is directed toward a winding-up center of the winding-up shaft when the sheet-like member is wound up by the winding-up shaft.

Abstract: A charging device includes a corona charger; a shutter of a sheet for shielding an opening of said corona charger, the sheet having such a property that it is curled about an axis when said shutter absorbs moisture; and a winding-up device for winding up the shutter. The axis and a winding-up direction in which the shutter is wound up by the winding-up means form an angle therebetween from 45 degrees to 135 degrees.