Abstract: According to an embodiment of the present invention, a sheet detection apparatus that detects a sheet includes an actuator unit that is rotatable around a rotational axis so as to adopt any of a protruding position in which the actuator unit protrudes into a detection area for detecting the sheet and a retracted position in which the actuator unit is retracted from the detection area, and an operation unit that is capable of switching between a retracted state in which the actuator unit is set to the retracted position and a protruding state in which the actuator unit is set to the protruding position. An image forming apparatus according to an embodiment of the present invention includes the sheet detection apparatus, and the sheet detection apparatus is provided in a main body of the image forming apparatus.

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: 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: 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: A shifting mechanism includes a guide plate, a bearing, a rotating shaft, a delivery roller, and a bearing unit. The shifting mechanism delivers a sheet of paper along a delivery passage and offsets the sheet horizontally and perpendicularly to the passage while delivering it. The guide plate has an opening forming part of the delivery passage and an end hole formed through the front end of the plate horizontally and perpendicularly to the passage. The rotating shaft extends through the end hole. The delivery roller is fixed to the rotating shaft. The sheet passes through the nip between the delivery roller and the guide plate. The bearing unit extends movably through the end hole and includes a sleeve, which supports the rotating shaft horizontally and perpendicularly to the delivery passage. The bearing unit rotates the rotating shaft.

Abstract: As one embodiment, a paper feeding device is provided with a pickup roller for pulling out an uppermost positioned sheet of loaded sheets, and a paper feeding roller for transporting the sheet pulled out by the pickup roller. Spanning between the pickup roller and the paper feeding roller, a roller belt is provided that is capable of moving relatively in a circumferential direction with respect to an outer circumferential surface of the paper feeding roller. The roller belt obtains rotational drive from the pickup roller.

Abstract: In one embodiment of the present invention, a sheet transport apparatus is provided with a registration roller, a sheet transport path, a first optical sensor, a second sensor that detects the presence or absence of a sheet at an upstream side of the first optical sensor in a sheet transportation direction Xd, and a sheet transportation control unit that stops the driving of the registration roller after an elapse of a transportation time after the detection of sheet absence following sheet presence by the first optical sensor, wherein the sheet transportation control unit does not perform control with sheet detection by the first optical sensor within a detection restricted time after predetermined sheet detection by the second sensor when the sheet is of a specific type.

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 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: As one embodiment, a paper feeding device is provided with a pickup roller for pulling out an uppermost positioned sheet of loaded sheets, and a paper feeding roller for transporting the sheet pulled out by the pickup roller. Spanning between the pickup roller and the paper feeding roller, a roller belt is provided that is capable of moving relatively in a circumferential direction with respect to an outer circumferential surface of the paper feeding roller. The roller belt obtains rotational drive from the pickup roller.

Abstract: A shifting mechanism includes a guide plate, a bearing, a rotating shaft, a delivery roller, and a bearing unit. The shifting mechanism delivers a sheet of paper along a delivery passage and offsets the sheet horizontally and perpendicularly to the passage while delivering it. The guide plate has an opening forming part of the delivery passage and an end hole formed through the front end of the plate horizontally and perpendicularly to the passage. The rotating shaft extends through the end hole. The delivery roller is fixed to the rotating shaft. The sheet passes through the nip between the delivery roller and the guide plate. The bearing unit extends movably through the end hole and includes a sleeve, which supports the rotating shaft horizontally and perpendicularly to the delivery passage. The bearing unit rotates the rotating shaft.

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: A sheet feeding apparatus includes first and second sheet sensors provided in order from upstream to downstream sides in feeding direction on a paper feed path, sheet conveyor roller sets arranged along the path, and a roller controller individually controlling groups of rollers on the upstream and downstream sides of the first sheet sensor, in response to a change in values of output signals from first and second sheet sensors. The roller controller includes an overlapped feeding determining device outputting a determination signal assuming a first value when overlapped feeding occurs and a second value otherwise, in response to the change in values of the output signals from the sensors, an overlapped feeding eliminating device eliminating overlapped feeding by controlling the roller controller upon receiving the determination signal of the first value, and a conveyor roller stopping device stopping the sheet conveyor rollers if the overlapped feeding eliminating process should fail.

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.

Abstract: A feeding device according to the present invention holds a pile of sheets of paper in it. Feed force so acts selectively on a specified region of the upper side of the held top sheet as to feed the held sheets one after one in a feed direction. The feeding device includes a flat press plate and a support. The press plate is not smaller in the feed direction and the cross directions perpendicular to the feed direction than the maximum size of the sheets which can be held in the main body. The press plate is not larger in the feed and cross directions than the inner size of the main body. The press plate has a first opening formed over the specified region. The press plate is supported vertically movably above the held sheets by the support.