Abstract: A mode in which a toner image formed on an intermediate transfer belt passes through a primary transfer portion without a toner image being transferred from a photosensitive drum onto the intermediate transfer belt is provided. In the mode, an area of the photosensitive drum that passes through the primary transfer portion while the toner image is passing through the primary transfer portion is defined as a first area. When the first area passes through a charging position, a charging bias is adjusted so that the occurrence of an image defect is prevented.

Abstract: An image forming apparatus includes a control unit that performs two types of stop operations in which an image bearing member is rotated or is not rotated after forming an image. The control unit selects the stop operation according to operation time of the image bearing member.

Abstract: In a rotary-type image forming apparatus in which detection of electrostatic capacitance is performed when a developing apparatus is in a posture less affected by a toner density within the developing apparatus, a toner in the developing apparatus, which is located at a development position during the detection of the electrostatic capacitance, is avoided from being uselessly consumed. The image forming apparatus has a remaining amount detection mode of detecting a toner remaining amount on condition that a developing roller of one developing apparatus positioned opposite to another developing apparatus, for which the toner remaining amount is to be detected, stands by in a state spaced from a drum.

Abstract: A charge bias causing the surface potential of a photosensitive drum to be lower than that in image formation is applied to a charge roller during a period in which the stop position of a rotary is moved from an unknown state to a home position to cause a developing bias to be applied to a developing roller to be smaller than that in the image formation.

Abstract: In a rotary-type image forming apparatus in which detection of electrostatic capacitance is performed when a developing apparatus is in a posture less affected by a toner density within the developing apparatus, a toner in the developing apparatus, which is located at a development position during the detection of the electrostatic capacitance, is avoided from being uselessly consumed. The image forming apparatus has a remaining amount detection mode of detecting a toner remaining amount on condition that a developing roller of one developing apparatus positioned opposite to another developing apparatus, for which the toner remaining amount is to be detected, stands by in a state spaced from a drum.

Abstract: A mode in which a toner image formed on an intermediate transfer belt passes through a primary transfer portion without a toner image being transferred from a photosensitive drum onto the intermediate transfer belt is provided. In the mode, an area of the photosensitive drum that passes through the primary transfer portion while the toner image is passing through the primary transfer portion is defined as a first area. When the first area passes through a charging position, a charging bias is adjusted so that the occurrence of an image defect is prevented.

Abstract: An image forming apparatus includes a control unit that performs two types of stop operations in which an image bearing member is rotated or is not rotated after forming an image. The control unit selects the stop operation according to operation time of the image bearing member.

Abstract: A charge bias causing the surface potential of a photosensitive drum to be lower than that in image formation is applied to a charge roller during a period in which the stop position of a rotary is moved from an unknown state to a home position to cause a developing bias to be applied to a developing roller to be smaller than that in the image formation.

Abstract: An image forming apparatus suppresses the deposition of transfer-residual toner on a sealing sheet and also suppresses the dropping of deposited toner therefrom, at a high temperature and in a high humidity environment. The apparatus includes a photosensitive drum, a cleaning blade for removing toner, a housing portion for housing the toner removed by the cleaning blade, and a sealing sheet for preventing the leakage of toner and performs charge elimination upstream of the sealing sheet in the direction of movement of the photosensitive drum, wherein a work function difference between the sealing sheet and the photosensitive drum is equal to or greater than 0.25 eV.

Abstract: A charging device for electrically charging an image bearing member, includes a contact charging member contactable to the image bearing member to charge the image bearing member, the contact charging member being supplied only with a DC voltage; and a contact member contacted to the charging member, wherein the image bearing member is adapted to carry a toner image of toner which contains an externally added material comprising silica, wherein work functions of the charging member, the contact member and the silica satisfy, (the work function of the contact member)>(the work function of the silica)>(the work function of the charging member).

Abstract: It is an object to suppress the deposition of transfer-residual toner on a sealing sheet and also to suppress the dropping of deposited toner therefrom, at a high temperature and high humidity environment. An image forming apparatus includes a photosensitive drum 100, a cleaning blade 601 for removing toner, a housing portion 603 for housing the toner removed by the cleaning blade 601, and a sealing sheet 602 for preventing the leakage of toner and performs charge elimination upstream of the sealing sheet 602 in the direction of movement of the photosensitive drum 100, wherein the work function difference between the sealing sheet 602 and the photosensitive drum 100 is equal to or greater than 0.25 eV.

Abstract: A developing apparatus including: a developer carrying member for carrying a developer, the developer carrying member being provided with an elastic layer and adapted to develop, with a developer, an electrostatic image formed on an image bearing member; wherein the developer includes a toner, the toner has a shape factor SF-1 of 100 or more but less than 130, the toner has a storage modulus G? (140° C.) at 140° C. of 2.0×103 dN/m2 or more but less than 2.0×104 dN/m2, the toner has a temperature, when the toner has a viscosity of 1.0×103 Pa·s in a flow tester temperature elevation method, of 115° C. or more but less than 130° C., and, in a surface roughness of the developer carrying member, a center-line mean roughness Ra, a ten-point mean roughness Rz and a mean spacing Sm of irregularities satisfy following relationships (1): 0.06 ? Rz / Sm ? 0.4 0.8 ? Ra ? 2.0 ? ? ( ? ? ? m ) } .

Abstract: A charging device for electrically charging an image bearing member, includes a contact charging member contactable to the image bearing member to charge the image bearing member, the contact charging member being supplied only with a DC voltage; and a contact member contacted to the charging member, wherein the image bearing member is adapted to carry a toner image of toner which contains an externally added material comprising silica, wherein work functions of the charging member, the contact member and the silica satisfy, (the work function of the contact member)>(the work function of the silica)>(the work function of the charging member).

Abstract: A developing apparatus including: a developer carrying member for carrying a developer, the developer carrying member being provided with an elastic layer and adapted to develop, with a developer, an electrostatic image formed on an image bearing member; wherein the developer includes a toner, the toner has a shape factor SF-1 of 100 or more but less than 130, the toner has a storage modulus G? (140° C.) at 140° C. of 2.0×103 dN/m2 or more but less than 2.0×104 dN/m2, the toner has a temperature, when the toner has a viscosity of 1.0×103 Pa·s in a flow tester temperature elevation method, of 115° C. or more but less than 130° C., and, in a surface roughness of the developer carrying member, a center-line mean roughness Ra, a ten-point mean roughness Rz and a mean spacing Sm of irregularities satisfy following relationships (1): 0.06 ? Rz / Sm ? 0.4 0.8 ? Ra ? 2.