Abstract: In a sheet transport apparatus, coiled springs 82 are fitted in and supported by recess portions 81b at a bottom face 81a of a support frame 81 and recess portions 73c at an upper face 73b of an inner guide 73. In other words, most of the portions of the coiled spring 82 are enclosed inside the recess portions 81b of the support frame 81 and the recess portions 73c of the inner guide 73, and covered and hidden by side walls 81f of the recess portions 81b and side walls 73d of the recess portions 73c.

Abstract: A transport path switching unit is provided between transport rollers and pre-registration rollers, and control is performed to switch between a main transport path and an extended transport path of the transport path switching unit such that either the main transport path or the extended transport path is interposed as the part of the paper transport path between the transport rollers and the pre-registration rollers to vary a total length of the paper transport path.

Abstract: A paper feeding device 200 provided in an image forming apparatus 1A according to one embodiment of the present invention is provided with a loading member 201 in which sheets P can be stacked and a central bending section 210 configured to upwardly raise a sheet transport direction X central area P2 of the sheet P for sheets P stacked in the loading member 201.

Abstract: A sheet feeding device includes a sheet support, a restricting portion, a displacement section, and a link section. The restricting portion slides along a line passing through restricting points. The restricting portion restricts the position of the sheet when the restricting portion is positioned at each of the restricting points. The link section interlinks the restricting portion and the displacement section. The position of the displacement section is detected. The link section, which interlinks the restricting section and the displacement section, is configured to change a ratio of a distance that the displacement section travels as the restricting section travels a fixed distance, wherein the ratio of the distance between those restricting points which define a relatively large spacing therebetween becomes longer than the ratio of the distance between those restricting points which define a relatively small spacing therebetween.

Abstract: To provide a fusing unit including a fusing roller for fixing an unfixed toner image to a sheet and a fusing roller cleaning unit including a web sheet delivering roller for supplying a web sheet and a winding roller for taking up the web sheet for cleaning the fusing roller, the fusing roller cleaning unit includes a web detecting terminal for detecting the presence of the web sheet and a tension roller for guiding the web sheet, on the upstream side of a pressure roller with respect to the web sheet's direction of conveyance and first and second guide rollers, the second guide roller being disposed upstream of the web detecting terminal.

Abstract: A feeding device according to the present invention includes a box, paper holders, and a shifting mechanism. The box is open at its top. The paper holders are open at their tops and positioned in the box. Each of the paper holders holds a pile of sheets of paper in it. The shifting mechanism so shifts at least one of the paper holders that the top sheet in one of the paper holders is positioned in a single feed position in the box according to selection data output from the apparatus with which the feeding device is used.

Abstract: When two or more sheets of paper P are fed in an overlapped manner to a nip where a paper feed roller and a separation roller are in pressure contact with each other, a sub-CPU of a sheet feeding unit rotates the paper feed roller in a paper feeding direction and rotates the separation roller in a direction opposite to the feeding direction, so as to separate overlapping, and thereafter, it rotates the paper feed roller and the separation roller again in the feeding direction.

Abstract: An image forming apparatus comprising: a main body having an image forming section; a sheet feed section having a sheet cassette that accommodates a recording sheet and can be drawn out and loaded to the main body; and a sheet misalignment preventing mechanism that intermittently comes into contact with an uppermost recording sheet in the sheet cassette so as to prevent misalignment of the recording sheet in a loading direction when the sheet cassette drawn out of the main body is reloaded.

Abstract: In a fixing unit, a fixing roller is rotated under driving force transmitted from a paper discharge unit-side gear of a driving section via a fixing roller driving gear, and holds and conveys a recording medium in cooperation with a pressure roller in a nip region. When a control section determines that acceleration conditions are fulfilled, the driving section increases the rotating speed of the paper discharge unit-side gear so that it is rotated at higher speed than before-acceleration speed over predetermined high-speed rotating period.

Abstract: In one embodiment of the invention, in an image forming apparatus that reverses the front and back of recording paper by performing switchback transport of the recording paper to perform duplex printing of the recording paper, the image forming apparatus is provided with a control means that, when performing duplex printing of the recording paper, forms a void area at a leading end and a trailing end of the recording paper, the void area preventing curling of the recording paper around a roller.

Abstract: An image forming apparatus including: a paper feed cassette; a paper pickup roller; an image forming portion; a fixing unit; a paper discharge portion for discharging paper P with a developer image fused and fixed thereon; and an inversion roller and a paper discharge drive roller for conveying paper P along a paper conveyance path, and is constructed such that guide ribs are provided for a curved portion in a main conveyance path and the first and second curved portions of a sub conveyance path are provided in shapes that will not cause concentration of stress acting on the paper P in abutment.

Abstract: In a sheet transport apparatus according to one embodiment of the present invention, coiled springs 82 are fitted in and supported by recess portions 81b at a bottom face 81a of a support frame 81 and recess portions 73c at an upper face 73b of an inner guide 73. In other words, most of the portions of the coiled spring 82 are enclosed inside the recess portions 81b of the support frame 81 and the recess portions 73c of the inner guide 73, and covered and hidden by side walls 81f of the recess portions 81b and side walls 73d of the recess portions 73c.

Abstract: A sheet feeding device includes a sheet support, a restricting portion, a displacement section, and a link section. The restricting portion slides along a line passing through restricting points. The restricting portion restricts the position of the sheet when the restricting portion is positioned at each of the restricting points. The link section interlinks the restricting portion and the displacement section. The position of the displacement section is detected. The link section, which interlinks the restricting section and the displacement section, is configured to change a ratio of a distance that the displacement section travels as the restricting section travels a fixed distance, wherein the ratio of the distance between those restricting points which define a relatively large spacing therebetween becomes longer than the ratio of the distance between those restricting points which define a relatively small spacing therebetween.

Abstract: A fixing apparatus is provided with a fixing roller that fixes a toner image that has been transferred onto a paper, a cleaning member that cleans a circumferential surface of the fixing roller using a metal roller that is idly rotated by contacting the circumferential surface of the fixing roller, a drive control means that, at a predetermined timing, sets a rotation velocity of the fixing roller to high-speed rotation that is faster by a predetermined velocity than a rotation velocity during print processing, a load torque detection means that detects a load torque of a drive source of the fixing roller, and a determination means that determines an extent of smearing of the cleaning member based on a load torque detected by the load torque detection means during high-speed rotation by the drive control means.

Abstract: A paper feeder comprises an acquiring device, a driving roller, driven rollers, a driven roller supporter, a driver, and a controller. The acquiring device acquires thickness information on a sheet of paper. The driving roller rotates by being supplied with torque. The driven rollers rotate with the driving roller when in compressive contact with the driving roller. The driven roller supporter so supports the driven rollers that each of them can rotate under a different rotational load. The driver changes the position of the driven roller supporter relative to the driving roller. The controller selects one of the driven rollers on the basis of the thickness information and so activates the driver as to bring the selected roller into compressive contact with the driving roller.

Abstract: A paper feeding device 200 provided in an image forming apparatus 1A according to one embodiment of the present invention is provided with a loading member 201 in which sheets P can be stacked and a central bending section 210 configured to upwardly raise a sheet transport direction X central area P2 of the sheet P for sheets P stacked in the loading member 201.

Abstract: In a fixing unit, a fixing roller is rotated under driving force transmitted from a paper discharge unit-side gear of a driving section via a fixing roller driving gear, and holds and conveys a recording medium in cooperation with a pressure roller in a nip region. When a control section determines that acceleration conditions are fulfilled, the driving section increases the rotating speed of the paper discharge unit-side gear so that it is rotated at higher speed than before-acceleration speed over predetermined high-speed rotating period.

Abstract: To provide a fusing unit including a fusing roller for fixing an unfixed toner image to a sheet and a fusing roller cleaning unit including a web sheet delivering roller for supplying a web sheet and a winding roller for taking up the web sheet for cleaning the fusing roller, the fusing roller cleaning unit includes a web detecting terminal for detecting the presence of the web sheet and a tension roller for guiding the web sheet, on the upstream side of a pressure roller with respect to the web sheet's direction of conveyance and first and second guide rollers, the second guide roller being disposed upstream of the web detecting terminal.

Abstract: A manual sheet feeding mechanism adapted for use in a sheet processing apparatus includes a manual feeding tray and a guiding member. The manual feeding tray is adapted to be mounted on a side wall of the apparatus so as to be pivotable about an axis between an open position and a closed position. The manual feeding tray has a placement surface for placing a sheet to be manually fed into the apparatus. The guiding member is adapted to position a sheet placed on the placement surface and is provided so as to be movable on the placement surface. The manual sheet feeding mechanism also includes a moving member that is adapted, when the manual feeding tray is pivoted toward the closed position, to move the guiding member on the placement surface.

Abstract: When two or more sheets of paper P are fed in an overlapped manner to a nip where a paper feed roller and a separation roller are in pressure contact with each other, a sub-CPU of a sheet feeding unit rotates the paper feed roller in a paper feeding direction and rotates the separation roller in a direction opposite to the feeding direction, so as to separate overlapping, and thereafter, it rotates the paper feed roller and the separation roller again in the feeding direction.