Abstract: An image forming apparatus includes an image forming station for forming a toner image on a sheet; an image heating portion including a flexible heating roller and a pressing roller to form a nip, the image heating portion being effective to heat while feeding the sheet, by the nip; a pressing state switching portion for switching a state of the nip between a pressing state and a released state; and a sheet feeding position detector for detecting misalignment of the sheet relative to a feeding reference position with respect to a direction perpendicular to a feeding direction of the sheet; wherein when the sheet feeding position detector detects the misalignment, the pressing state switching portion permits the nip to feed at least one sheet in a state of the misalignment, and then switches the nip to the released state and then switches to the pressing state.

Abstract: An image heating apparatus, for heating, in a nip, a recording material for carrying a toner image while conveying the recording material, includes a flexible cylindrical film; a nip-forming member contacting an inner surface of the film; and a pressing member for forming the nip between itself and the film. The inner surface of the film is provided with a roughened surface portion in a region in which the nip-forming member slides on the inner surface of the film. The roughened surface portion has a skewness Rsk satisfying: Rsk<0.

Abstract: An image forming apparatus includes: an image bearing member for bearing a toner image; a belt for conveying the toner image; and a transfer device for rubbing the belt, and a surface of the transfer device, which is brought into contact with the belt includes linear concave portions or linear convex portions. The image forming apparatus of the present invention prevents a friction force between the belt and the transfer device rubbing the belt from increasing and brings a transfer member into a stable contact with the belt for conveying the toner image, thereby suppressing increase in drive torque of the belt which rubs the transfer device and suppressing occurrence of image failure.

Abstract: Test patches are formed such that lengths of the test patches in a rotational direction of the intermediate transfer member are shorter than a length of the intermediate transfer member from a primary transfer portion located in the lowermost stream among the plurality of primary transfer portions to the secondary transfer portion.

Abstract: An image forming apparatus includes: an image bearing member for bearing a toner image; a belt for conveying the toner image; and a transfer device for rubbing the belt, and a surface of the transfer device, which is brought into contact with the belt includes linear concave portions or linear convex portions. The image forming apparatus of the present invention prevents a friction force between the belt and the transfer device rubbing the belt from increasing and brings a transfer member into a stable contact with the belt for conveying the toner image, thereby suppressing increase in drive torque of the belt which rubs the transfer device and suppressing occurrence of image failure.

Abstract: An image forming apparatus includes an image bearing member for carrying a toner image, a movable intermediary transfer member for receiving the toner image from the image bearing member, a primary transfer member for primary transfer of the toner image from the image bearing member onto the intermediary transfer member, a secondary transfer member for being supplied with a voltage and for secondary transfer of the toner image from the intermediary transfer member onto a transfer material, and a first toner charging member. A first charging member rubs a surface of the intermediary transfer member with movement thereof, and a second charging member moves in contact with the intermediary transfer member, thereby transferring toner remaining on the intermediary transfer member after the secondary transfer back to the image bearing member from the intermediary transfer member simultaneously with the primary transfer at the primary transfer station.

Abstract: An image forming apparatus includes: image forming unit configured to form a density detection pattern and a reference pattern on an image carrier by a developer; a light-receiving unit configured to receive reflection light of light emitted toward the image carrier, and output a signal corresponding to an amount of received light; a sampling unit configured to sample the signal output from the light-receiving unit, and store sampling values in the storage unit; a detection unit configured to detect the reference pattern; and a determination unit configured to determine a sampling value corresponding to reflection light from the density detection pattern of the color among the sampling values stored in the storage unit, based on a detection time of the reference pattern.

Abstract: An image forming apparatus includes a control unit configured to detect a misregistration amount and densities of the toner images by detecting first and second detection patterns. The first detection pattern includes black and color portions, and the control unit is further configured to set a light-emitting amount of a detection unit, a threshold, or a sensitivity of a detection unit so that a received light amount of diffuse reflection light from the black portion is less than the threshold and a received light amount of diffuse reflection light from the color portion exceeds the threshold, and to set the light-emitting amount or the sensitivity so that the received light amount of the diffuse reflection light from the color portion is less than an upper limit of the detection unit.

Abstract: An image forming apparatus includes: a forming unit configured to continuously form, on an image carrier, a first and second detection patterns for detecting relative registration amounts and a density of each of a plurality of colors; and a control unit configured to control registration and the density. The forming unit forms the detection patterns such that a leading edge developer color of a detection pattern formed on a front side among the two detection patterns, in a direction in which the detection patterns are moved by rotation of the image carrier, is the same as a trailing edge developer color of the detection pattern formed on the front side, or a leading or trailing edge developer color of a detection pattern formed on a rear side among the two detection patterns.

Abstract: An image forming apparatus includes: an image forming unit configured to form, on an image carrier, a first correction pattern including developer images of a plurality of colors, and a second correction pattern including developer images of the plurality of colors; a registration correction unit configured to perform registration correction control based on a detection result of the developer images of the first correction pattern; and a density correction unit configured to perform density correction control based on a detection result of the second correction pattern. The density correction unit is further configured to decide a detection result of the developer image of at least one color of the second correction pattern used for the density correction control based on a detection result of the developer image of the first correction pattern.

Abstract: The optical sensor includes a light-emitting element configured to emit light to a light emitted surface, a light-receiving element configured to receive reflection light from the light emitted surface, the reflection light including light emitted from the light-emitting element and reflected at the light emitted surface, a circuit board including a mounting surface on which the light-emitting element and the light-receiving element are mounted, and a housing fixed to the circuit board. The housing includes a light shielding portion provided between the light-emitting element and the light-receiving element, and the light shielding portion is engaged with a hole formed in the circuit board at a position between the light-emitting element and the light-receiving element.

Abstract: An image forming apparatus for forming image on a recording medium includes a photosensitive member, a motor, a belt, and a drive member to rotate the belt, the drive member including a driven coupling. The apparatus also includes a drive coupling to rotate by a driving force generated by the motor, the drive coupling being movable in an axial direction to take an engagement position at which the driving force is transmittable to the driven coupling, and a release position. The apparatus further includes a transfer member to transfer a toner image onto the recording medium or the belt, a voltage application unit to apply a voltage to the transfer member, and a control unit to cause the voltage application unit to apply the voltage to the transfer member after the drive coupling moves to the engagement position and the driving force is transmitted to the driven coupling.

Abstract: An image forming apparatus includes an image bearing member for bearing a toner image; an endless rotatable intermediary transfer belt onto which the toner image is to be transferred from the image bearing member; a transfer device disposed at a position in which the transfer device opposes the image bearing member through the intermediary transfer belt, the transfer device including a sheet member surface-contacted to an inner surface of the intermediary transfer belt and including an urging member for urging the sheet member toward the intermediary transfer belt; and a primary transfer voltage source for applying a voltage to the sheet member.

Abstract: An image forming apparatus includes: an image bearing member for bearing a toner image; a belt for conveying the toner image; and a transfer device for rubbing the belt, and a surface of the transfer device, which is brought into contact with the belt includes linear concave portions or linear convex portions. The image forming apparatus of the present invention prevents a friction force between the belt and the transfer device rubbing the belt from increasing and brings a transfer member into a stable contact with the belt for conveying the toner image, thereby suppressing increase in drive torque of the belt which rubs the transfer device and suppressing occurrence of image failure.

Abstract: A charge member charges secondary transfer remaining toner on an intermediate transfer member to a polarity opposite to a normal charge polarity. The remaining toner is moved by a transfer bias, from the intermediate transfer member onto an image bearing member. A BK station is arranged on the downstream of other stations. In a continuous BK monochromatic mode, by applying a reverse bias to transfer portions of the other stations and applying the transfer bias only to the BK station, remaining toner can be collected into the BK station (simultaneously with the transfer). In a full-color mode, remaining toner is collected into the station on the uppermost stream. Thus, the image bearing member for collecting remaining toner on the intermediate transfer member differs according to the mode, thereby suppressing the collection of remaining toner being concentrated on one image bearing member.

Abstract: An image forming apparatus includes an image forming station for forming a toner image on a sheet; an image heating portion including a flexible heating roller and a pressing roller to form a nip, the image heating portion being effective to heat while feeding the sheet, by the nip; a pressing state switching portion for switching a state of the nip between a pressing state and a released state; and a sheet feeding position detector for detecting misalignment of the sheet relative to a feeding reference position with respect to a direction perpendicular to a feeding direction of the sheet; wherein when the sheet feeding position detector detects the misalignment, the pressing state switching portion permits the nip to feed at least one sheet in a state of the misalignment, and then switches the nip to the released state and then switches to the pressing state.

Abstract: An image heating apparatus, for heating, in a nip, a recording material for carrying a toner image while conveying the recording material, includes a flexible cylindrical film; a nip-forming member contacting an inner surface of the film; and a pressing member for forming the nip between itself and the film. The inner surface of the film is provided with a roughened surface portion in a region in which the nip-forming member slides on the inner surface of the film. The roughened surface portion has a skewness Rsk satisfying: Rsk<0.

Abstract: An image forming apparatus includes: an image bearing member for bearing a toner image; a belt for conveying the toner image; and a transfer device for rubbing the belt, and a surface of the transfer device, which is brought into contact with the belt includes linear concave portions or linear convex portions. The image forming apparatus of the present invention prevents a friction force between the belt and the transfer device rubbing the belt from increasing and brings a transfer member into a stable contact with the belt for conveying the toner image, thereby suppressing increase in drive torque of the belt which rubs the transfer device and suppressing occurrence of image failure.

Abstract: A charge member charges secondary transfer remaining toner on an intermediate transfer member to a polarity opposite to a normal charge polarity. The remaining toner is moved by a transfer bias, from the intermediate transfer member onto an image bearing member. A BK station is arranged on the downstream of other stations. In a continuous BK monochromatic mode, by applying a reverse bias to transfer portions of the other stations and applying the transfer bias only to the BK station, remaining toner can be collected into the BK station (simultaneously with the transfer). In a full-color mode, remaining toner is collected into the station on the uppermost stream. Thus, the image bearing member for collecting remaining toner on the intermediate transfer member differs according to the mode, thereby suppressing the collection of remaining toner being concentrated on one image bearing member.

Abstract: There is a charge member which charges secondary transfer remaining toner on an intermediate transfer member to a polarity opposite to a normal charge polarity. The transfer remaining toner charged by the charge member is moved in the direction opposite to that of normal toner by a transfer bias and moved from the intermediate transfer member onto an image bearing member. A BK station is arranged on the downstream of other stations. In a continuous BK monochromatic mode, by applying a reverse bias to transfer portions of the other stations and applying the transfer bias only to the BK station, waste toner can be collected into the BK station (simultaneously with the transfer). In a full-color mode, since each transfer bias is applied to all stations, the waste toner is collected into the station on the uppermost stream.