Abstract: An image forming apparatus (100) is equipped with a plurality of photoreceptor drums (31A to 31D), an intermediate transfer belt (41), a separating and contacting mechanisms (20), a tension roller (44), a meandering correction mechanism, and a controller. The separating and contacting mechanism (20) displaces the intermediate transfer belt (41). The meandering correction mechanism increases and decreases a biasing force applied to each of the opposite end portions of the tension roller (44) according to the amount of movement of the intermediate transfer belt (41) in the axial direction (94) of the tension roller (44). The controller, during a non-image forming period, at a predetermined timing during rotation of the intermediate transfer belt (41), executes a belt displacement process in which the intermediate transfer belt (41) is displaced from a predetermined reference position and then returned to the reference position.

Abstract: An image forming apparatus (100) is equipped with a plurality of photoreceptor drums (31A to 31D), an intermediate transfer belt (41), a separating and contacting mechanisms (20), a tension roller (44), a meandering correction mechanism, and a controller. The separating and contacting mechanism (20) displaces the intermediate transfer belt (41). The meandering correction mechanism increases and decreases a biasing force applied to each of the opposite end portions of the tension roller (44) according to the amount of movement of the intermediate transfer belt (41) in the axial direction (94) of the tension roller (44). The controller, during a non-image forming period, at a predetermined timing during rotation of the intermediate transfer belt (41), executes a belt displacement process in which the intermediate transfer belt (41) is displaced from a predetermined reference position and then returned to the reference position.

Abstract: A belt driving device includes an endless belt, a tension roller, a shaft member, deviation transfer members, and biasing members. The deviation transfer members are fitted over the shaft member in such a manner as to adjoin respective of opposite ends of the tension roller in an axial direction of the tension roller. Of the deviation transfer members, at least that deviation transfer member which is located on a downstream side in a deviation direction along the axial direction is movable together with the endless belt along the shaft member. Each of the biasing members has an acting end pivotally supported on an associated one of the deviation transfer members and a base end pivotally supported on an associated one of apparatus frames at a predetermined position.

Abstract: A belt driving device includes an endless belt, a tension roller, a shaft member, deviation transfer members, and biasing members. The deviation transfer members are fitted over the shaft member in such a manner as to adjoin respective of opposite ends of the tension roller in an axial direction of the tension roller. Of the deviation transfer members, at least that deviation transfer member which is located on a downstream side in a deviation direction along the axial direction is movable together with the endless belt along the shaft member. Each of the biasing members has an acting end pivotally supported on an associated one of the deviation transfer members and a base end pivotally supported on an associated one of apparatus frames at a predetermined position.

Abstract: In a sheet detecting sensor, light emitted from a linear light emitting element is blocked by a sheet from entering a light receiving element which is located immediately below the sheet. Only light receiving elements which are not immediately below the sheet, receive light from the linear light emitting element. Light passing through a point in a vicinity of an edge portion of the sheet enters only a light receiving element which is located immediately below that point, but not the other light receiving elements. In addition, even when the position of a sheet varies vertically, the same light receiving element receives light passing through the same point in a vicinity of the edge portion of the sheet. Therefore, even when the position of a sheet varies vertically, the edge position of the sheet can be accurately detected.

Abstract: A line sensor that detects the edge position of a recording paper is provided on the upstream side of a transfer point where an image formed on a first photosensitive drum is transferred to the recording paper. When performing borderless image formation, the size of the image on the first photosensitive drum to be transferred to the midstream of the recording paper after detection of its edge position is changed to a smaller size based on the detection results by the line sensor, and subsequent image formation to the recording paper continues to be performed according to this image on the photosensitive drum whose size has been changed.

Abstract: According to the present invention, highly accurate adjustment of the angles and positions of optical elements constituting an optical scanning unit can be easily performed. For a cylindrical lens that makes the light beam for exposing a photoreceptor converge on the surface of the photoreceptor, a frame is provided for holding the cylindrical lens therein. The frame is supported by two support portions for a chassis of the optical scanning unit such that the longitudinal direction of the cylindrical lens becomes parallel to the scanning direction of the photoreceptor. The optical scanning unit is configured such that the angle of the cylindrical lens in the longitudinal direction is adjustable in the sub-scanning direction of the photoreceptor at the support portion on the front side (operational side) of these support portions.

Abstract: According to the present invention, highly accurate adjustment of the angles and positions of optical elements constituting an optical scanning unit can be easily performed. The optical scanning unit comprises: a first mirror that reflects the light beams emitted from Y, C and M laser diodes; a second mirror that reflects the light beam emitted from a K laser diode and the light beams reflected by the first mirror; a cylindrical lens that acts on the light beams reflected by the second mirror; and a third mirror that reflects the light beams emitted from the cylindrical lens toward a polygon mirror. The second mirror is provided with an adjusting mechanism that can adjust the light beams in the main scanning direction, and the third mirror is provided with an adjusting mechanism that can adjust the light beams in the sub-scanning direction.

Abstract: The subject invention provides a sheet feeding device which can be easily attached to an image forming apparatus. The sheet feeding device includes an adapting part and a lock section. When the sheet feeding device is attached to the image forming apparatus, the adapting part is hooked to a catch section provided in the image forming apparatus. Then, the sheet feeding device is lifted up by the adapting part, which serves as a fulcrum, so as to attach lock section to an attachment board of the image forming apparatus. In this method, it is not necessary to lift up the entire body of the sheet feeding device, and therefore the sheet feeding device can be installed on the image forming apparatus with a little effort. After installation, the sheet feeding device transfers recording sheets to the image forming apparatus via a sheet feeding opening.

Abstract: According to the present invention, highly accurate adjustment of the angles and positions of optical elements constituting an optical scanning unit can be easily performed. The optical scanning unit comprises: a first mirror that reflects the light beams emitted from Y, C and M laser diodes; a second mirror that reflects the light beam emitted from a K laser diode and the light beams reflected by the first mirror; a cylindrical lens that acts on the light beams reflected by the second mirror; and a third mirror that reflects the light beams emitted from the cylindrical lens toward a polygon mirror. The second mirror is provided with an adjusting mechanism that can adjust the light beams in the main scanning direction, and the third mirror is provided with an adjusting mechanism that can adjust the light beams in the sub-scanning direction.

Abstract: According to the present invention, highly accurate adjustment of the angles and positions of optical elements constituting an optical scanning unit can be easily performed. For a cylindrical lens that makes the light beam for exposing a photoreceptor converge on the surface of the photoreceptor, a frame is provided for holding the cylindrical lens therein. The frame is supported by two support portions for a chassis of the optical scanning unit such that the longitudinal direction of the cylindrical lens becomes parallel to the scanning direction of the photoreceptor. The optical scanning unit is configured such that the angle of the cylindrical lens in the longitudinal direction is adjustable in the sub-scanning direction of the photoreceptor at the support portion on the front side (operational side) of these support portions.

Abstract: The subject invention provides a sheet feeding device which can be easily attached to an image forming apparatus. The sheet feeding device includes an adapting part and a lock section. When the sheet feeding device is attached to the image forming apparatus, the adapting part is hooked to a catch section provided in the image forming apparatus. Then, the sheet feeding device is lifted up by the adapting part, which serves as a fulcrum, so as to attach lock section to an attachment board of the image forming apparatus. In this method, it is not necessary to lift up the entire body of the sheet feeding device, and therefore the sheet feeding device can be installed on the image forming apparatus with a little effort. After installation, the sheet feeding device transfers recording sheets to the image forming apparatus via a sheet feeding opening.

Abstract: A line sensor that detects the edge position of a recording paper is provided on the upstream side of a transfer point where an image formed on a first photosensitive drum is transferred to the recording paper. When performing borderless image formation, the size of the image on the first photosensitive drum to be transferred to the midstream of the recording paper after detection of its edge position is changed to a smaller size based on the detection results by the line sensor, and subsequent image formation to the recording paper continues to be performed according to this image on the photosensitive drum whose size has been changed.

Abstract: The temperature difference between an internal temperature and an external temperature which are detected by an internal temperature sensor and an external temperature sensor, respectively, is calculated. If the internal temperature is lower by not less than predetermined degrees than the external temperature and, hence, condensation on the surface of each optical component within a laser writing unit is highly likely, a motor is driven to rotate a polygonal mirror. During its operation the motor generates heat, which in turn transfers from a flange portion directly to a housing while heating air around the laser writing unit. Further, air within the housing is stirred by rotation of the polygonal mirror. In this way the temperature of the entire laser writing unit is raised.

Abstract: The temperature difference between an internal temperature and an external temperature which are detected by an internal temperature sensor and an external temperature sensor, respectively, is calculated. If the internal temperature is lower by not less than predetermined degrees than the external temperature and, hence, condensation on the surface of each optical component within a laser writing unit is highly likely, a motor is driven to rotate a polygonal mirror. During its operation the motor generates heat, which in turn transfers from a flange portion directly to a housing while heating air around the laser writing unit. Further, air within the housing is stirred by rotation of the polygonal mirror. In this way the temperature of the entire laser writing unit is raised.

Abstract: In a sheet detecting sensor, light emitted from a linear light emitting element is blocked by a sheet from entering a light receiving element which is located immediately below the sheet. Only light receiving elements which are not immediately below the sheet, receive light from the linear light emitting element. Light passing through a point in a vicinity of an edge portion of the sheet enters only a light receiving element which is located immediately below that point, but not the other light receiving elements. In addition, even when the position of a sheet varies vertically, the same light receiving element receives light passing through the same point in a vicinity of the edge portion of the sheet. Therefore, even when the position of a sheet varies vertically, the edge position of the sheet can be accurately detected.

Abstract: In an image forming system, an image forming device and a post-treatment device are provided so as to keep a distance L therebetween, by a positioning member and a transfer relaying device, and the image forming device is connected with the post-treatment device by the transfer relaying device. With this arrangement, a space surrounded by the image forming device, post-treatment device, positioning member, and transfer relaying device is made. On this account, it is possible to provide an image forming system in which an image forming device is coupled with a peripheral unit, which does not require cumbersome operations to make a space between the image forming device and the peripheral unit, on the occasion of carrying out unjamming treatment between the image forming device and the peripheral unit.

Abstract: In an image forming system, an image forming device and a post-treatment device are provided so as to keep a distance L therebetween, by a positioning member and a transfer relaying device, and the image forming device is connected with the post-treatment device by the transfer relaying device. With this arrangement, a space surrounded by the image forming device, post-treatment device, positioning member, and transfer relaying device is made. On this account, it is possible to provide an image forming system in which an image forming device is coupled with a peripheral unit, which does not require cumbersome operations to make a space between the image forming device and the peripheral unit, on the occasion of carrying out unjamming treatment between the image forming device and the peripheral unit.