Abstract: In a lock member of a pull-out lock device, while two adjacent sheet containers are both located at an accommodated position in an image-forming apparatus main body, a contact member is in contact with one of the sheet containers and thus the lock member rotates around a rotation axis, and a lock moves to an unlock position to allow the other sheet container to move in a pull-out direction, and while the other sheet container is located at the accommodated position and the one of the sheet containers is pulled out from the accommodated position in the pull-out direction and thus the contact between the one of the sheet containers and the contact member is removed, the lock member rotates around the rotation axis and the lock moves to a lock position to prohibit the other sheet container from moving in the pull-out direction.

Abstract: A sheet feeding device includes a rotation shaft that rotates in synchronism with rotation of the feed member, a spring clutch that is deformable to be in a tightened state and to be in a loosened state, and a pressure-receiving member that becomes displaced from a first position to a second position by receiving a pressing force that is generated as the spring clutch swings. The spring clutch starts to be loosened from the tightened state as a first end portion of the spring clutch becomes engaged with an engagement portion when the pressure-receiving member is displaced to the second position.

Abstract: A sheet feeding device includes a rotation shaft that rotates in synchronism with rotation of the feed member, a spring clutch that is deformable to be in a tightened state and to be in a loosened state, and a pressure-receiving member that becomes displaced from a first position to a second position by receiving a pressing force that is generated as the spring clutch swings. The spring clutch starts to be loosened from the tightened state as a first end portion of the spring clutch becomes engaged with an engagement portion when the pressure-receiving member is displaced to the second position.

Abstract: The elastic force of a spring 41 in a direction of an arrow X is applied to an end 51A of a coil spring 5A in a direction of an arrow Y through a holding plate 42. The end 52A of the coil spring 5A is engaged with a holding hole 12 and regulated from moving in the direction of the arrow Y. The elastic force of the spring 41 in the direction of the arrow X is constantly applied to the coil spring 5A in a direction in which the peripheral surface of the support post 3 is tightened.

Abstract: The elastic force of a spring 41 in a direction of an arrow X is applied to an end 51A of a coil spring 5A in a direction of an arrow Y through a holding plate 42. The end 52A of the coil spring 5A is engaged with a holding hole 12 and regulated from moving in the direction of the arrow Y. The elastic force of the spring 41 in the direction of the arrow X is constantly applied to the coil spring 5A in a direction in which the peripheral surface of the support post 3 is tightened.

Abstract: The elastic force of a spring 41 in a direction of an arrow X is applied to an end 51A of a coil spring 5A in a direction of an arrow Y through a holding plate 42. The end 52A of the coil spring 5A is engaged with a holding hole 12 and regulated from moving in the direction of the arrow Y. The elastic force of the spring 41 in the direction of the arrow X is constantly applied to the coil spring 5A in a direction in which the peripheral surface of the support post 3 is tightened.

Abstract: The elastic force of a spring 41 in a direction of an arrow X is applied to an end 51A of a coil spring 5A in a direction of an arrow Y through a holding plate 42. The end 52A of the coil spring 5A is engaged with a holding hole 12 and regulated from moving in the direction of the arrow Y. The elastic force of the spring 41 in the direction of the arrow X is constantly applied to the coil spring 5A in a direction in which the peripheral surface of the support post 3 is tightened.

Abstract: An image forming apparatus including a pair of rollers that rotate, that selectively carries out forward direction transport and switchback transport, including a guide member provided at a downstream side from the rollers in the forward direction transport that moves to either a first position or a second position, and a control portion causing the guide member to move to the first position during the forward direction transport and causing the guide member to move to the second position during the switchback transport. The first position is a position in which the guide member is retracted from a path of the recording paper on a downstream side from the rollers in the forward direction transport. The second position is a position in which the recording paper sandwiched between the rollers can be received on the guide member.

Abstract: An image forming apparatus including a pair of rollers that rotate, that selectively carries out forward direction transport and switchback transport, including a guide member provided at a downstream side from the rollers in the forward direction transport that moves to either a first position or a second position, and a control portion causing the guide member to move to the first position during the forward direction transport and causing the guide member to move to the second position during the switchback transport. The first position is a position in which the guide member is retracted from a path of the recording paper on a downstream side from the rollers in the forward direction transport. The second position is a position in which the recording paper sandwiched between the rollers can be received on the guide member.

Abstract: For an electrostatic latent image formed on an image carrier (31b), besides an operation forming an “image forming electrostatic latent image” used to form the primary image, an operation is executed that forms an “electrostatic latent image for removing developer” for removing developer that resides on a developer supply member (53a) for a predetermined time period onto the image carrier (31b). Thus, developer is nearly eliminated from residing on this developer supply member (53a) in an overcharged state for a long period of time, and generation of a fogged image is avoided as much as possible.

Abstract: An optical scanning unit irradiates a polygon mirror with a plurality of light beams emitted from a light source according to image data, and scans and exposes a plurality of photoreceptors with the plurality of light beams as scanning lights. The optical scanning unit comprises a primary optical system unit including an optical system that emits the plurality of light beams, which are emitted from the light source toward the polygon mirror, and a secondary optical system unit including an optical system that emits the light beams, which are reflected by the polygon mirror toward the photoreceptors. The arrangement is such that the primary optical system unit is fitted removably to the secondary optical system unit, and that a combined unit of the primary optical system unit and the secondary optical system unit is removably fitted to an image forming apparatus having the photoreceptors.

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: A discharge unit is disposed downstream of a principal transport path of a compound machine, and a shifter function is provided in this discharge unit. By shifting the paper passage position relative to a photosensitive drum when printing the front side and the paper passage position relative to the photosensitive drum when printing the back side, the region in which the surface electric potential of the photosensitive drum increases is diminished, and the region in which photographic fog is generated is made smaller. Thus, when printing the second and subsequent sheets, even when a slight amount of displacement of the transport position of the recording paper occurs, it is possible to suppress that recording paper making contact in the photographic fog region on the photosensitive drum, and defective printing can be prevented.

Abstract: In an image forming apparatus in which positioned below a development unit for accommodating a toner is an exposure unit that writes to a photosensitive drum by exposing an electrostatic latent image, an aperture portion on an upper surface of an exposure unit case positioned in an optical path of light from the exposure unit is provided so as to not become an impediment to the optical path of the light and a glass plate is inclined and provided on the aperture portion. An inclination angle of the glass plate is set to an angle inclined 40° with respect to a horizontal line so as to be greater than a repose angle of the toner when the toner has poor fluidity under a condition of high temperature and high humidity.

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: An optical scanning unit irradiates a polygon mirror with a plurality of light beams emitted from a light source according to image data, and scans and exposes a plurality of photoreceptors with the plurality of light beams as scanning lights. The optical scanning unit comprises a primary optical system unit including an optical system that emits the plurality of light beams, which are emitted from the light source toward the polygon mirror, and a secondary optical system unit including an optical system that emits the light beams, which are reflected by the polygon mirror toward the photoreceptors. The arrangement is such that the primary optical system unit is fitted removably to the secondary optical system unit, and that a combined unit of the primary optical system unit and the secondary optical system unit is removably fitted to an image forming apparatus having the photoreceptors.

Abstract: For an electrostatic latent image formed on an image carrier (31b), besides an operation forming an “image forming electrostatic latent image” used to form the primary image, an operation is executed that forms an “electrostatic latent image for removing developer” for removing developer that resides on a developer supply member (53a) for a predetermined time period onto the image carrier (31b). Thus, developer is nearly eliminated from residing on this developer supply member (53a) in an overcharged state for a long period of time, and generation of a fogged image is avoided as much as possible.

Abstract: A discharge unit is disposed downstream of a principal transport path of a compound machine, and a shifter function is provided in this discharge unit. By shifting the paper passage position relative to a photosensitive drum when printing the front side and the paper passage position relative to the photosensitive drum when printing the back side, the region in which the surface electric potential of the photosensitive drum increases is diminished, and the region in which photographic fog is generated is made smaller. Thus, when printing the second and subsequent sheets, even when a slight amount of displacement of the transport position of the recording paper occurs, it is possible to suppress that recording paper making contact in the photographic fog region on the photosensitive drum, and defective printing can be prevented.

Abstract: In an image forming apparatus in which positioned below a development unit for accommodating a toner is an exposure unit that writes to a photosensitive drum by exposing an electrostatic latent image, an aperture portion on an upper surface of an exposure unit case positioned in an optical path of light from the exposure unit is provided so as to not become an impediment to the optical path of the light and a glass plate is inclined and provided on the aperture portion. An inclination angle of the glass plate is set to an angle inclined 40° with respect to a horizontal line so as to be greater than a repose angle of the toner when the toner has poor fluidity under a condition of high temperature and high humidity.