Abstract: An image forming apparatus includes a tray, a roller unit, an image forming unit, and a pressing mechanism. The roller unit includes a feed roller disposed above a downstream end portion of the tray in a sheet conveying direction in which a sheet is conveyed, a separation roller disposed downstream of the feed roller in the sheet conveying direction, and a roller holder pivotable about a rotation axis of the separation roller, the roller holder holding the feed roller rotatably about an axis of the feed roller and pivotably vertically. The pressing mechanism includes an arm member configured to press the roller holder such that the roller holder pivots downward, and a weight portion provided to the arm member and applying, to the arm member, a load in a direction in which the feed roller is raised from the upper surface of the sheet supported on the tray.

Abstract: In a sheet conveyor, a stopper piece of a sheet stopper temporarily stops a sheet supported on a sheet tray, and a pickup roller conveys the sheet from the sheet tray in a sheet conveying direction. A first sheet sensor disposed upstream of a registration roller and downstream of the stopper piece in the sheet conveying direction detects a leading edge of the sheet, and a second sheet sensor disposed downstream of the registration roller detects the leading edge of the sheet. A first contact member of the first sheet sensor receives the leading edge of the sheet. A second contact member of the second sheet sensor receives the leading edge of the sheet. The stopper piece, the first contact member, and the second contact member are offset from each other in a direction perpendicular to the sheet conveying direction and unaligned with each other in the sheet conveying direction.

Abstract: A sheet feeding apparatus includes a feed roller, a roller holder supporting the feed roller rotatably about a rotation axis, a frame supporting the roller holder pivotably about a first axis parallel to the rotation axis of the feed roller, a force-transmitting device configured to transmit, to the roller holder, a force with which to cause the roller holder to pivot in a direction where the feed roller is pressed against a tray, a force-applying member movable between a force applying position where the force-applying member contacts the force-transmitting device to apply the force thereto and a force-free position where the force-applying member is spaced apart from the force-transmitting device, and a cushioning member configured to, when the force-applying member is at an initial contact positon located between the force applying position and the force-free position, be sandwiched in contact between the force-transmitting device and the force-applying member.

Abstract: In a sheet conveyor, a stopper piece of a sheet stopper temporarily stops a sheet supported on a sheet tray, and a pickup roller conveys the sheet from the sheet tray in a sheet conveying direction. A first sheet sensor disposed upstream of a registration roller and downstream of the stopper piece in the sheet conveying direction detects a leading edge of the sheet, and a second sheet sensor disposed downstream of the registration roller detects the leading edge of the sheet. A first contact member of the first sheet sensor receives the leading edge of the sheet. A second contact member of the second sheet sensor receives the leading edge of the sheet. The stopper piece, the first contact member, and the second contact member are offset from each other in a direction perpendicular to the sheet conveying direction and unaligned with each other in the sheet conveying direction.

Abstract: A sheet feeding apparatus includes a feed roller, a roller holder supporting the feed roller rotatably about a rotation axis, a frame supporting the roller holder pivotably about a first axis parallel to the rotation axis of the feed roller, a force-transmitting device configured to transmit, to the roller holder, a force with which to cause the roller holder to pivot in a direction where the feed roller is pressed against a tray, a force-applying member movable between a force applying position where the force-applying member contacts the force-transmitting device to apply the force thereto and a force-free position where the force-applying member is spaced apart from the force-transmitting device, and a cushioning member configured to, when the force-applying member is at an initial contact positon located between the force applying position and the force-free position, be sandwiched in contact between the force-transmitting device and the force-applying member.

Abstract: An image forming apparatus includes a tray, a roller unit, an image forming unit, and a pressing mechanism. The roller unit includes a feed roller disposed above a downstream end portion of the tray in a sheet conveying direction in which a sheet is conveyed, a separation roller disposed downstream of the feed roller in the sheet conveying direction, and a roller holder pivotable about a rotation axis of the separation roller, the roller holder holding the feed roller rotatably about an axis of the feed roller and pivotably vertically. The pressing mechanism includes an arm member configured to press the roller holder such that the roller holder pivots downward, and a weight portion provided to the arm member and applying, to the arm member, a load in a direction in which the feed roller is raised from the upper surface of the sheet supported on the tray.

Abstract: An image forming apparatus is provided, which includes photoconductive drums arranged along a sheet conveyance direction, transfer bodies each disposed to face a corresponding one of the photoconductive drums, a fuser unit disposed downstream relative to a most downstream photoconductive drum in the sheet conveyance direction and configured to feed a sheet at a feeding speed lower than a feeding speed of the most downstream photoconductive drum, and a controller configured to, when the sheet is not in contact with any photoconductive drum but the most downstream photoconductive drum, perform a specific voltage applying mode to apply, to a most downstream transfer body in the sheet conveyance direction, a higher voltage than when the sheet is in contact with two or more photoconductive drums.

Abstract: An image forming apparatus includes a first roller and a second roller spaced apart from the first roller, a belt being endless and extending around the first roller and the second roller, a photosensitive member, a transfer member, and a conductor. The belt is configured to move in a moving direction. The belt has a first surface and a second surface. The first surface extends from the first roller to the second roller in the moving direction, and the second surface extends from the second roller to the first roller in the moving direction. The photosensitive member is disposed facing the first surface of the belt and configured to carry a developer image thereon. The transfer member is disposed facing toward the photosensitive member and configured to transfer the developer image on the photosensitive member. The conductor is electrically grounded and disposed facing the second surface of the belt.

Abstract: A transfer device is provided, which includes a transfer roller that is provided with a conductive rotational shaft, opposed to an external image-carrying body, and configured to transfer onto an image-transferred member a developer image carried by the image-carrying body, and a bearing rotatably supporting the rotational shaft of the transfer roller, the bearing including a conductive section that is disposed in a position around the rotational shaft of the transfer roller and configured to bear the rotational shaft from an opposite side of the image-carrying body with respect to the rotational shaft and to be supplied with electricity from an external power supply, and an insulated section that is disposed in a position around the rotational shaft and configured to cover the image-carrying body from a side of the image-carrying body.

Abstract: An image forming apparatus is provided, which includes photoconductive drums arranged along a sheet conveyance direction, transfer bodies each disposed to face a corresponding one of the photoconductive drums, a fuser unit disposed downstream relative to a most downstream photoconductive drum in the sheet conveyance direction and configured to feed a sheet at a feeding speed lower than a feeding speed of the most downstream photoconductive drum, and a controller configured to, when the sheet is not in contact with any photoconductive drum but the most downstream photoconductive drum, perform a specific voltage applying mode to apply, to a most downstream transfer body in the sheet conveyance direction, a higher voltage than when the sheet is in contact with two or more photoconductive drums.

Abstract: An image forming device, comprising: an image formation unit; an endless belt; first, second and third rollers arranged in parallel such that the belt extends therebetween; a collar that is provided at least at one of ends in an axial direction of the first roller and moves in the axial direction when the belt moves obliquely; a press arm that presses an one axial end side of the second roller on which the collar is provided; and an oblique motion force conversion unit that includes a cam on which an slanting surface is formed and a movable part slidably contacting the slanting surface, and that converts a force for moving the collar into a pressing force for pressing the press arm, and wherein the slanting surface becomes closer to a rotation center of the first roller at a point further from the belt.

Abstract: An image forming apparatus is provided. The image forming apparatus includes an image forming unit to transfer an image onto a transfer medium in an image transfer range, a seamless belt to move along a predetermined conveying direction, a pair of belt rollers to support the belt in a flattened condition, a tensile force applier to become in contact with the belt and apply tensile force to the belt in the image transfer range, a controller to apply the tensile force during an imaging period, in which operations including an image transfer operation are executed, and reduce or clear the tensile force being applied to the belt during a non-imaging period, which is other than the imaging period.

Abstract: An image forming apparatus includes a first roller and a second roller spaced apart from the first roller, a belt being endless and extending around the first roller and the second roller, a photosensitive member, a transfer member, and a conductor. The belt is configured to move in a moving direction. The belt has a first surface and a second surface. The first surface extends from the first roller to the second roller in the moving direction, and the second surface extends from the second roller to the first roller in the moving direction. The photosensitive member is disposed facing the first surface of the belt and configured to carry a developer image thereon. The transfer member is disposed facing toward the photosensitive member and configured to transfer the developer image on the photosensitive member. The conductor is electrically grounded and disposed facing the second surface of the belt.

Abstract: A transfer device is provided, which includes a transfer roller that is provided with a conductive rotational shaft, opposed to an external image-carrying body, and configured to transfer onto an image-transferred member a developer image carried by the image-carrying body, and a bearing rotatably supporting the rotational shaft of the transfer roller, the bearing including a conductive section that is disposed in a position around the rotational shaft of the transfer roller and configured to bear the rotational shaft from an opposite side of the image-carrying body with respect to the rotational shaft and to be supplied with electricity from an external power supply, and an insulated section that is disposed in a position around the rotational shaft and configured to cover the image-carrying body from a side of the image-carrying body.

Abstract: An image forming device, comprising: an image formation unit; an endless belt; first, second and third rollers arranged in parallel such that the belt extends therebetween; a collar that is provided at least at one of ends in an axial direction of the first roller and moves in the axial direction when the belt moves obliquely; a press arm that presses an one axial end side of the second roller on which the collar is provided; and an oblique motion force conversion unit that includes a cam on which an slanting surface is formed and a movable part slidably contacting the slanting surface, and that converts a force for moving the collar into a pressing force for pressing the press arm, and wherein the slanting surface becomes closer to a rotation center of the first roller at a point further from the belt.

Abstract: An image forming apparatus is provided. The image forming apparatus includes an image forming unit to transfer an image onto a transfer medium in an image transfer range, a seamless belt to move along a predetermined conveying direction, a pair of belt rollers to support the belt in a flattened condition, a tensile force applier to become in contact with the belt and apply tensile force to the belt in the image transfer range, a controller to apply the tensile force during an imaging period, in which operations including an image transfer operation are executed, and reduce or clear the tensile force being applied to the belt during a non-imaging period, which is other than the imaging period.