Abstract: An image forming apparatus includes an image forming section, an intermediate transfer belt, and a stretching roller. The intermediate transfer belt has a pair of test regions on opposite sides of a printing region in the width direction, and the image forming section transfers a test pattern image to the test regions. The image forming apparatus further includes an image density sensor and a counter-sensor member having a counter portion facing the image density sensor across the intermediate transfer belt. The edge positions of the counter portion in the width direction are inward, in the width direction, of the edge positions of the stretching roller in the width direction.

Abstract: A transfer unit includes a seamless transfer belt, a plurality of transfer rollers, a backup roller, a plurality of pairs of first bearing holders, a pair of second bearing holders and a pair of sliders. Each of the sliders is reciprocated such that each of the first bearing holders slides on the corresponding one of the first step ribs to be reciprocated in a direction toward and away from the transfer belt and the second bearing holder slides on the second step rib to be reciprocated in the direction toward and away from the transfer belt. The first step rib arranged most upstream in the direction of travel of the transfer belt and the second step rib are arranged side by side in the axial direction of the transfer roller, and overlap each other when viewed in the axial direction.

Abstract: Provided is an image forming apparatus including: an apparatus main body; an intermediate transfer unit; and an image-bearing-member unit. the intermediate transfer unit includes an intermediate transfer belt, a frame, a drive roller, a tension roller, a transfer roller that is movable between a transfer position and a retractive position. The frame includes a first protrusion. The image-bearing-member unit includes an image bearing member, and a first regulating guide that extends in an axial direction of the image bearing member, and that faces the first protrusion in the upper-and-lower direction. The intermediate transfer belt and the image bearing member face each other with a predetermined length therebetween under a state in which the first protrusion and the first regulating guide are held in contact with each other, and in which the transfer roller has come to the retractive position.

Abstract: A transfer unit includes a seamless transfer belt, a plurality of transfer rollers, a backup roller, a plurality of pairs of first bearing holders, a pair of second bearing holders and a pair of sliders. Each of the sliders is reciprocated such that each of the first bearing holders slides on the corresponding one of the first step ribs to be reciprocated in a direction toward and away from the transfer belt and the second bearing holder slides on the second step rib to be reciprocated in the direction toward and away from the transfer belt. The first step rib arranged most upstream in the direction of travel of the transfer belt and the second step rib are arranged side by side in the axial direction of the transfer roller, and overlap each other when viewed in the axial direction.

Abstract: A belt conveying device includes a correction mechanism, a belt cleaning unit, a roller retaining member, a cleaning support member, and a posture maintaining unit. When a belt is meandering, the correction mechanism allows one end side of a meandering correction roller in an axial direction to move in the direction perpendicular to the axial direction, so as to correct meandering of the belt. The posture maintaining unit connects the roller retaining member and the cleaning support member, so as to maintain posture of the belt cleaning unit with respect to the meandering correction roller.

Abstract: A belt unit includes a belt that is endless, a plurality of stretching rollers, a pair of side frames and one or more shafts. The side frames are each provided with bearing holes that rotatably support opposite end parts of the stretching rollers, and positioning holes into which opposite end parts of the shafts are inserted. The shafts each have formed therein a first engagement groove that engages with a first holding jig. The stretching rollers each have formed therein a second engagement groove that engages with a second holding jig. When the first engagement groove is in engagement with the first holding jig, the shafts are arranged opposite the positioning holes corresponding thereto, and have a phase thereof restricted in a circumferential direction thereof. When the second engagement groove is in engagement with the second holding jig, the stretching rollers are arranged opposite the bearing holes corresponding thereto.

Abstract: An image forming apparatus includes a photoconductor drum, a developing roller, a first shaft provided for one of the photoconductor drum and the developing roller, a second shaft provided for the other of the photoconductor drum and the developing roller, a first housing supporting the first shaft, and removable in an axial direction of the first shaft, a second housing supporting the second shaft, and removable in an axial direction of the second shaft, a first contact member provided on an axial end portion of the first housing, a second contact member provided on an axial end portion of the second housing, and located in contact with the first contact member, a first cover covering the first contact member, and a first cleaning device provided on the first cover, and configured to rub against the second contact member, when the second housing is inserted or removed.

Abstract: A belt unit includes a belt that is endless, a plurality of stretching rollers, a pair of side frames and one or more shafts. The side frames are each provided with bearing holes that rotatably support opposite end parts of the stretching rollers, and positioning holes into which opposite end parts of the shafts are inserted. The shafts each have formed therein a first engagement groove that engages with a first holding jig. The stretching rollers each have formed therein a second engagement groove that engages with a second holding jig. When the first engagement groove is in engagement with the first holding jig, the shafts are arranged opposite the positioning holes corresponding thereto, and have a phase thereof restricted in a circumferential direction thereof. When the second engagement groove is in engagement with the second holding jig, the stretching rollers are arranged opposite the bearing holes corresponding thereto.

Abstract: An intermediate transfer device includes an intermediate transfer belt, a plurality of primary transfer rollers, a plurality of pairs of support members, a biasing member, a pair of movable members, and a pair of frame members. The plurality of pairs of support members rotatably support both end parts of respective rotary shafts of the plurality of primary transfer rollers and are pivotable in directions in which the primary transfer rollers approach and separate from the intermediate transfer belt. The pair of movable members makes contact with the support members on both end sides of the rotary shafts of the plurality of primary transfer rollers so as to cause the support members to pivot. In a rotation axis direction of the primary transfer rollers, the movable members are disposed between the pair of frame members and within an extending range of the intermediate transfer belt.

Abstract: An image forming apparatus includes a plurality of image carrying members, an intermediate transfer belt, a plurality of rollers, and a correcting mechanism. The intermediate transfer belt is endless and, to it, toner images formed on the image carrying members respectively are transferred by being sequentially superposed on each other. The correction mechanism includes a slanted bearing, which rotatably supports a tension roller, and a main body guide roller, which makes contact with the slanted bearing when it moves as a result of the intermediate transfer belt meandering and which moves the slanted bearing along with one end of the tension roller in the axial direction in the direction perpendicular to the axial direction to correct meandering of the intermediate transfer belt with respect to the tension roller. The main body guide roller is a rotary member which rotates while in contact with the slanted bearing.

Abstract: An intermediate transfer device includes an intermediate transfer belt, a plurality of primary transfer rollers, a plurality of pairs of support members, a biasing member, a pair of movable members, and a pair of frame members. The plurality of pairs of support members rotatably support both end parts of respective rotary shafts of the plurality of primary transfer rollers and are pivotable in directions in which the primary transfer rollers approach and separate from the intermediate transfer belt. The pair of movable members makes contact with the support members on both end sides of the rotary shafts of the plurality of primary transfer rollers so as to cause the support members to pivot. In a rotation axis direction of the primary transfer rollers, the movable members are disposed between the pair of frame members and within an extending range of the intermediate transfer belt.

Abstract: An image forming apparatus includes a plurality of image carriers, an intermediate transfer belt, a plurality of rollers, a correction mechanism, and a belt cleaning unit. The intermediate transfer belt has an endless shape, and toner images respectively formed on the plurality of image carriers are sequentially overlaid and transferred thereto. The correction mechanism moves one end side in an axial direction of a tension roller along a direction perpendicular to the axial direction, so as to correct meandering of the intermediate transfer belt with respect to the tension roller. The belt cleaning unit includes a cleaning blade that is disposed in such a manner that its tip portion contacts with an outer circumferential surface of the intermediate transfer belt at a position facing the tension roller via the intermediate transfer belt, so as to remove extraneous matter from the outer circumferential surface of the intermediate transfer belt.

Abstract: An image forming apparatus includes a plurality of image carrying members, an intermediate transfer belt, a plurality of rollers, and a correcting mechanism. The intermediate transfer belt is endless and, to it, toner images formed on the image carrying members respectively are transferred by being sequentially superposed on each other. The correction mechanism includes a slanted bearing, which rotatably supports a tension roller, and a main body guide roller, which makes contact with the slanted bearing when it moves as a result of the intermediate transfer belt meandering and which moves the slanted bearing along with one end of the tension roller in the axial direction in the direction perpendicular to the axial direction to correct meandering of the intermediate transfer belt with respect to the tension roller. The main body guide roller is a rotary member which rotates while in contact with the slanted bearing.

Abstract: An image forming apparatus includes a plurality of image carriers, an intermediate transfer belt, a plurality of rollers, a correction mechanism, and a belt cleaning unit. The intermediate transfer belt has an endless shape, and toner images respectively formed on the plurality of image carriers are sequentially overlaid and transferred thereto. The correction mechanism moves one end side in an axial direction of a tension roller along a direction perpendicular to the axial direction, so as to correct meandering of the intermediate transfer belt with respect to the tension roller. The belt cleaning unit includes a cleaning blade that is disposed in such a manner that its tip portion contacts with an outer circumferential surface of the intermediate transfer belt at a position facing the tension roller via the intermediate transfer belt, so as to remove extraneous matter from the outer circumferential surface of the intermediate transfer belt.

Abstract: A fixing device includes a fixing member, a pressuring member and a temperature sensing part. The fixing member heated by a heat source contacts with a recording medium to heat a toner image on the recording medium. The pressuring member pressures the recording medium to the fixing member. The temperature sensing part in non-contact with the fixing member includes an infrared sensing element sensing infrared rays from the fixing member and a condensing member condensing the infrared rays to the infrared sensing element. Detection temperature of the fixing member is calculated with a sensing value by the infrared sensing element. The detection temperature or control temperature of the heat source is corrected with temperature deference between the infrared sensing element and the condensing member. Heating of the fixing member is controlled with the corrected detection temperature and the control temperature or the detection temperature and the corrected control temperature.

Abstract: A fixing device includes a fixing member, a pressuring member and a temperature sensing part. The fixing member heated by a heat source contacts with a recording medium to heat a toner image on the recording medium. The pressuring member pressures the recording medium to the fixing member. The temperature sensing part in non-contact with the fixing member includes an infrared sensing element sensing infrared rays from the fixing member and a condensing member condensing the infrared rays to the infrared sensing element. Detection temperature of the fixing member is calculated with a sensing value by the infrared sensing element. The detection temperature or control temperature of the heat source is corrected with temperature deference between the infrared sensing element and the condensing member. Heating of the fixing member is controlled with the corrected detection temperature and the control temperature or the detection temperature and the corrected control temperature.

Abstract: An operation panel used in an image forming apparatus has a panel face, a semi-transparent member of a black or similar color, and a light source. The panel face has an operation region. The semi-transparent member is arranged such that its top face is approximately flush with the panel face at least along a peripheral part of it. The light source is arranged under the semi-transparent member in the peripheral part of the panel face.

Abstract: A toner case includes a case main body, a shutter mount and a shutter. The case main body contains a toner to be replenished to a development device provided in an apparatus main body and is detachably attached to the apparatus main body. The case main body has an opened face on which a discharge port is arranged and the discharge port corresponds to a replenishment port of the development device in a state where the case main body is attached to the apparatus main body. The shutter mount is provided to form a gap between the opened face of the case main body and the shutter mount. The shutter is provided between the opened face of the case main body and the shutter mount to be slidable to open and close the discharge port. The shutter mount includes a film which comes into sliding contact with the shutter.

Abstract: An operation panel used in an image forming apparatus has a panel face, a semi-transparent member of a black or similar color, and a light source. The panel face has an operation region. The semi-transparent member is arranged such that its top face is approximately flush with the panel face at least along a peripheral part of it. The light source is arranged under the semi-transparent member in the peripheral part of the panel face.

Abstract: A toner case includes a case main body, a shutter mount and a shutter. The case main body contains a toner to be replenished to a development device provided in an apparatus main body and is detachably attached to the apparatus main body. The case main body has an opened face on which a discharge port is arranged and the discharge port corresponds to a replenishment port of the development device in a state where the case main body is attached to the apparatus main body. The shutter mount is provided to form a gap between the opened face of the case main body and the shutter mount. The shutter is provided between the opened face of the case main body and the shutter mount to be slidable to open and close the discharge port. The shutter mount includes a film which comes into sliding contact with the shutter.