Abstract: An image forming apparatus includes an image carrying member, a charging device, an exposure device, a developing device, an intermediate transfer belt, a cleaning brush, an image density sensor, and a control portion. The control portion is capable of executing a cleaning performance determination mode for determining cleaning performance of the cleaning brush. The cleaning performance determination mode includes: a reference image formation process of forming a reference image on the intermediate transfer belt; and a first bare-surface-measurement process of detecting a reference-image formation area, using the image density sensor, after the intermediate transfer belt has rotated once. When a fluctuation range of an output waveform of the image density sensor in the first bare surface measurement process is equal to or less than a threshold value, it is determined that the cleaning performance of the cleaning brush is normal.

Abstract: An image forming apparatus includes an image carrying member, a charging device, an exposure device, a developing device, an intermediate transfer belt, a cleaning brush, an image density sensor, and a control portion. The control portion executes calibration including: a first adjustment process of changing an image forming condition based on a result of detection of a first reference image formed on the intermediate transfer belt; a first bare-surface-measurement process of detecting, after execution of the first adjustment process, a first-reference-image formation area; and a second adjustment process of changing, after execution of the first bare-surface-measurement process, the image forming condition based on a result of detection of a second reference image formed on the first-reference-image formation area. In a case where an output value of the image density sensor in the first bare-surface-measurement process is equal to or less than a threshold value, the second adjustment process is executed.

Abstract: An image forming apparatus includes a plurality of image carrying members, a charging device, an exposure device, a developing device, an intermediate transfer belt, and a plurality of transfer rollers. On the image carrying member disposed most downstream in the traveling direction of the intermediate transfer belt, a black tonner image is developed. The rotation shaft of at least one transfer roller located upstream of the transfer roller disposed most downstream in the traveling direction of the intermediate transfer belt is offset upstream from directly above the rotation shaft of the corresponding image carrying member.

Abstract: An image forming apparatus includes a two-component developer, a photosensitive member, a charging device, a development device and an intermediate transfer belt. The intermediate transfer belt contains a base resin and a conductive agent. The base resin includes a thermoplastic resin or a thermosetting resin. The photosensitive member includes a base member and an amorphous silicon photosensitive layer. The arithmetic average roughness Ra of the surface of the photosensitive member is equal to or greater than 37 nm but equal to or less than 105 nm. The toner particle includes a toner base particle and a toner external additive that is adhered to the surface of the toner base particle. The toner external additive includes a spacer particle. The number average primary particle diameter of the spacer particle is greater than the arithmetic average roughness Ra of the surface of the photosensitive member.

Abstract: An image forming apparatus includes a plurality of image carrying members, a charging device, an exposure device, a developing device, an intermediate transfer belt, and a plurality of transfer rollers. On the image carrying member disposed most downstream in the traveling direction of the intermediate transfer belt, a black tonner image is developed. The rotation shaft of at least one transfer roller located upstream of the transfer roller disposed most downstream in the traveling direction of the intermediate transfer belt is offset upstream from directly above the rotation shaft of the corresponding image carrying member.

Abstract: A fixing device includes a fixing member, a pressurizing member, a charging portion, and a control portion. The fixing member rotates while being heated. The pressurizing member forms a nip portion between itself and a surface of the fixing member in such a way as to hold a sheet therebetween and conveys the sheet by rotating together with the fixing member, wherein an image of toner has been formed on the sheet. The charging portion electrically charges the surface of the fixing member to a polarity that is same as a charging polarity of the toner by supplying a charging current to a pair of electrodes that is disposed to face the surface of the fixing member. The control portion derives an index value of a charge amount of the toner on the sheet, and adjusts the charging current based on the index value.

Abstract: A fixing device includes a fixing member, a pressurizing member, a charging portion, and a control portion. The fixing member rotates while being heated. The pressurizing member forms a nip portion between itself and a surface of the fixing member in such a way as to hold a sheet therebetween and conveys the sheet by rotating together with the fixing member, wherein an image of toner has been formed on the sheet. The charging portion electrically charges the surface of the fixing member to a polarity that is same as a charging polarity of the toner by supplying a charging current to a pair of electrodes that is disposed to face the surface of the fixing member. The control portion increases the charging current as time passes during a control time period that corresponds to a time period for which the sheet passes through the nip portion.

Abstract: A fixing device includes a fixing member, a pressurizing member, a charging portion, and a control portion. The fixing member rotates while being heated. The pressurizing member forms a nip portion between itself and a surface of the fixing member in such a way as to hold a sheet therebetween and conveys the sheet by rotating together with the fixing member, wherein an image of toner has been formed on the sheet. The charging portion electrically charges the surface of the fixing member to a polarity that is same as a charging polarity of the toner by supplying a charging current to a pair of electrodes that is disposed to face the surface of the fixing member. The control portion acquires sheet information that includes one or more of length information, width information, and thickness information of the sheet and adjusts the charging current based on the sheet information.

Abstract: A fixing device includes a fixing member, a pressurizing member, a charging portion, and a control portion. The fixing member rotates while being heated. The pressurizing member forms a nip portion between itself and a surface of the fixing member in such a way as to hold a sheet therebetween and conveys the sheet by rotating together with the fixing member, wherein an image of toner has been formed on the sheet. The charging portion electrically charges the surface of the fixing member to a polarity that is same as a charging polarity of the toner by supplying a charging current to a pair of electrodes that is disposed to face the surface of the fixing member. The control portion derives an index value of a charge amount of the toner on the sheet, and adjusts the charging current based on the index value.

Abstract: A fixing device includes a fixing member, a pressurizing member, a charging portion, and a control portion. The fixing member rotates while being heated. The pressurizing member forms a nip portion between itself and a surface of the fixing member in such a way as to hold a sheet therebetween and conveys the sheet by rotating together with the fixing member, wherein an image of toner has been formed on the sheet. The charging portion electrically charges the surface of the fixing member to a polarity that is same as a charging polarity of the toner by supplying a charging current to a pair of electrodes that is disposed to face the surface of the fixing member. The control portion acquires sheet information that includes one or more of length information, width information, and thickness information of the sheet and adjusts the charging current based on the sheet information.

Abstract: A fixing device includes a fixing member, a pressurizing member, a charging portion, and a control portion. The fixing member rotates while being heated. The pressurizing member forms a nip portion between itself and a surface of the fixing member in such a way as to hold a sheet therebetween and conveys the sheet by rotating together with the fixing member, wherein an image of toner has been formed on the sheet. The charging portion electrically charges the surface of the fixing member to a polarity that is same as a charging polarity of the toner by supplying a charging current to a pair of electrodes that is disposed to face the surface of the fixing member. The control portion increases the charging current as time passes during a control time period that corresponds to a time period for which the sheet passes through the nip portion.

Abstract: A fixing device includes a heating body, a pressuring body, a charging part and a collecting part. The heating body contacts with a medium having a toner image while rotating to heat the medium. The pressuring body forms a nip with the heating roller while rotating to pressure the medium passing through the nip with the heating body. The charging part is positioned to face to the heating body and electrically discharges to electrically charge the heating body with the same polarity as polarity of toner. The collecting part is positioned to face to a position at an upstream side with respect to a facing position on the heating body to the charging part and at a downstream side with respect to a forming position of the nip in a rotating direction of the heating body, and collects impurities caused by the medium passing the nip by absorbing or removing.

Abstract: A fixing device includes a heating body, a pressuring body, a charging part and a collecting part. The heating body contacts with a medium having a toner image while rotating to heat the medium. The pressuring body forms a nip with the heating roller while rotating to pressure the medium passing through the nip with the heating body. The charging part is positioned to face to the heating body and electrically discharges to electrically charge the heating body with the same polarity as polarity of toner. The collecting part is positioned to face to a position at an upstream side with respect to a facing position on the heating body to the charging part and at a downstream side with respect to a forming position of the nip in a rotating direction of the heating body, and collects impurities caused by the medium passing the nip by absorbing or removing.

Abstract: A cleaning device includes a cleaning member, a collecting roller and a cleaning blade. The cleaning member is disposed to be rotatable while being in contact with a surface of an image carrier configured to carry a toner image to the surface. The collecting roller is disposed to be rotatable while being in contact with the cleaning member at a downstream side from the image carrier in a rotation direction of the cleaning member. The cleaning blade is disposed while being in contact with the collecting roller in a counter direction with respect to rotation of the collecting roller at a downstream side from the cleaning member in a rotation direction of the collecting roller. The collecting roller is formed so as to have larger surface roughness at an end than that at a central part in an axial direction.

Abstract: A cleaning device includes a cleaning member, a collecting roller and a cleaning blade. The cleaning member is disposed to be rotatable while being in contact with a surface of an image carrier configured to carry a toner image to the surface. The collecting roller is disposed to be rotatable while being in contact with the cleaning member at a downstream side from the image carrier in a rotation direction of the cleaning member. The cleaning blade is disposed while being in contact with the collecting roller in a counter direction with respect to rotation of the collecting roller at a downstream side from the cleaning member in a rotation direction of the collecting roller. The collecting roller is formed so as to have larger surface roughness at an end than that at a central part in an axial direction.

Abstract: An image forming apparatus includes a toner containing portion, a first conveying member, an image conveying portion, and an image forming portion. The first conveying member is configured to convey the toner in a conveyance direction within the toner containing portion. The image conveying portion includes a surface layer portion having a first end portion located at an upstream side in the conveyance direction and a second end portion located at a downstream side in the conveyance direction. The first end portion has a larger layer thickness than second end portion. The image conveying portion is configured to convey a toner image formed on a surface of the surface layer portion at a predetermined image forming position, to a transfer position for transfer to a transfer target medium. The image forming portion is configured to form the toner image on the surface layer portion by using the toner being conveyed.

Abstract: An image forming apparatus includes: a photosensitive body including a photosensitive layer having a first end and a second end, the first end having a larger thickness than the second end; a charging portion charges the photosensitive layer; a light irradiation portion applies light to the photosensitive layer; a developing device develops by toner charged with the same polarity as charge polarity of the photosensitive layer; an intermediate transfer medium including a surface layer having a third end and a fourth end, the third end having a larger thickness than the fourth end, the third end being opposed to the second end, the fourth end being opposed to the first end; and a transfer portion transfers a toner image developed on the photosensitive layer, onto the surface layer when a voltage having polarity opposite to the charge polarity is applied to the transfer portion.

Abstract: An image forming apparatus includes a toner containing portion, a first conveying member, an image conveying portion, and an image forming portion. The first conveying member is configured to convey the toner in a conveyance direction within the toner containing portion. The image conveying portion includes a surface layer portion having a first end portion located at an upstream side in the conveyance direction and a second end portion located at a downstream side in the conveyance direction. The first end portion has a larger layer thickness than second end portion. The image conveying portion is configured to convey a toner image formed on a surface of the surface layer portion at a predetermined image forming position, to a transfer position for transfer to a transfer target medium. The image forming portion is configured to form the toner image on the surface layer portion by using the toner being conveyed.

Abstract: An image forming apparatus includes: a photosensitive body including a photosensitive layer having a first end and a second end, the first end having a larger thickness than the second end; a charging portion charges the photosensitive layer; a light irradiation portion applies light to the photosensitive layer; a developing device develops by toner charged with the same polarity as charge polarity of the photosensitive layer; an intermediate transfer medium including a surface layer having a third end and a fourth end, the third end having a larger thickness than the fourth end, the third end being opposed to the second end, the fourth end being opposed to the first end; and a transfer portion transfers a toner image developed on the photosensitive layer, onto the surface layer when a voltage having polarity opposite to the charge polarity is applied to the transfer portion.

Abstract: An image forming apparatus includes a development device, an electrostatic transfer device, a stopping period measuring part, a driving period measuring part, a toner consumption amount measuring part, an environment measuring part and a transferring bias adjusting part. The driving period measuring part measures a driving period in which the development device is driven in order to form the toner image. The transferring bias adjusting part adjusts the transferring bias on the basis of the stopping period measured by the stopping period measuring part, the driving period measured by the driving period measuring part, the toner consumption amount measured by the toner consumption amount measuring part and the condition of the surrounding environment measured by the environment measuring part.