Abstract: In a sheet feeding device, when a leading end of a recording sheet is guided to a nip region along a leading end portion of a sheet guide member in contact with a surface of a separation roller, the leading end of the recording sheet slides and moves on surfaces of projected end portions to be guided to the vicinity of the nip region, and the leading end of the recording sheet passes through the nip region quickly. Hence, a sheet feed error is much less likely to occur. Since a distance from recessed end portions to the nip region is longer and the leading end of the recording sheet is in contact with the separation roller for a longer time right after passing the recessed end portions until reaching the nip region, even though a plurality of recording sheets is stacked, the recording sheets are separated one by one by the separation roller, preventing a multi-sheet feed of the sheets.

Abstract: An image forming apparatus (100) includes a discharge section (210), a paper receiving tray (93), a first detecting section (211), a lever (220), a second detecting section (230) and a decision section (240). The first detecting section (211) is disposed in the discharge section (210), and detects a paper jam. The second detecting section (230) detects a swinging state of the lever (220) from a first position at which the lever (220) is not in the process of receiving an action of the paper sheet to a second position. The decision section (240) judges an occurrence factor in a paper jam to be a user-induced factor when the second detecting section (230) detects a state in which the lever is at the first position in a state where the first detecting section (211) detects the paper jam.

Abstract: A paper conveying device includes: a registration roller pair provided along a paper conveying path; a pick-up roller, a paper feed roller and a separation roller for feeding sheets of paper to the paper conveying path; and a controller controlling conveyance of sheets of paper such that when a preceding sheet is stopped at the registration roller pair, a following, succeeding sheet is temporarily stopped at a prescribed position G downstream of a conveying roller in the paper conveying direction, and the succeeding sheet is re-conveyed toward the registration roller pair at a prescribed timing. The controller changes the timing to start re-conveyance of the succeeding sheet in accordance with paper length of the conveyed sheet of paper.

Abstract: A sheet conveying device (30) includes a plurality of first conveyance rollers (31) and a plurality of second conveyance rollers (32). The sheet conveying device (30) includes stiffening rollers (34). The stiffening rollers (34) are disposed coaxially with at least one conveyance rollers (32) among the first and second conveyance rollers (31) and (32), and have diameters larger than diameters of the conveyance rollers (32). The stiffening rollers (34) includes first stiffening rollers (34a), which apply conveying forces to a sheet (P), and second stiffening rollers (34b), which apply smaller conveying forces to the sheet (P) than the conveying forces to the sheet (P) in the first stiffening rollers (34a).

Abstract: A sheet conveying device (30) includes a plurality of first conveyance rollers (31) and a plurality of second conveyance rollers (32). The sheet conveying device (30) includes stiffening rollers (34). The stiffening rollers (34) are disposed coaxially with at least one conveyance rollers (32) among the first and second conveyance rollers (31) and (32), and have diameters larger than diameters of the conveyance rollers (32). The stiffening rollers (34) includes first stiffening rollers (34a), which apply conveying forces to a sheet (P), and second stiffening rollers (34b), which apply smaller conveying forces to the sheet (P) than the conveying forces to the sheet (P) in the first stiffening rollers (34a).

Abstract: In a sheet feeding device, when a leading end of a recording sheet is guided to a nip region along a leading end portion of a sheet guide member in contact with a surface of a separation roller, the leading end of the recording sheet slides and moves on surfaces of projected end portions to be guided to the vicinity of the nip region, and the leading end of the recording sheet passes through the nip region quickly. Hence, a sheet feed error is much less likely to occur. Since a distance from recessed end portions to the nip region is longer and the leading end of the recording sheet is in contact with the separation roller for a longer time right after passing the recessed end portions until reaching the nip region, even though a plurality of recording sheets is stacked, the recording sheets are separated one by one by the separation roller, preventing a multi-sheet feed of the sheets.

Abstract: A paper conveying device includes: a registration roller pair provided along a paper conveying path; a pick-up roller, a paper feed roller and a separation roller for feeding sheets of paper to the paper conveying path; and a controller controlling conveyance of sheets of paper such that when a preceding sheet is stopped at the registration roller pair, a following, succeeding sheet is temporarily stopped at a prescribed position G downstream of a conveying roller in the paper conveying direction, and the succeeding sheet is re-conveyed toward the registration roller pair at a prescribed timing. The controller changes the timing to start re-conveyance of the succeeding sheet in accordance with paper length of the conveyed sheet of paper.

Abstract: A recording paper conveying device includes a registration roller pair and a conveyor roller pair adjacent to the registration roller pair. By rotating the conveyor roller pair, a sheet of recording paper is fed until leading edge of the sheet abuts the registration roller pair in stationary state so that the sheet is deflected by a prescribed amount. Then, conveyor roller pair is rotated at the constant velocity, and while the sheet is kept deflected, rotation of the registration roller pair is started, to start feeding of the sheet by the registration roller pair. While the registration roller pair is kept rotating, rotation of the conveyor roller pair is suspended, and then, the conveyor roller pair is returned to the state of rotation before suspension. Thus, unnecessary deflection of the sheet just in front of the registration roller pair can be prevented.

Abstract: A sheet conveying device (30) includes a plurality of first conveyance rollers (31) and a plurality of second conveyance rollers (32). The sheet conveying device (30) includes stiffening rollers (34). The stiffening rollers (34) are disposed coaxially with at least one conveyance rollers (32) among the first and second conveyance rollers (31) and (32), and have diameters larger than diameters of the conveyance rollers (32). The stiffening rollers (34) includes first stiffening rollers (34a), which apply conveying forces to a sheet (P), and second stiffening rollers (34b), which apply smaller conveying forces to the sheet (P) than the conveying forces to the sheet (P) in the first stiffening rollers (34a).

Abstract: A sheet conveying device (30) includes a plurality of first conveyance rollers (31) and a plurality of second conveyance rollers (32). The sheet conveying device (30) includes stiffening rollers (34). The stiffening rollers (34) are disposed coaxially with at least one conveyance rollers (32) among the first and second conveyance rollers (31) and (32), and have diameters larger than diameters of the conveyance rollers (32). The stiffening rollers (34) includes first stiffening rollers (34a), which apply conveying forces to a sheet (P), and second stiffening rollers (34b), which apply smaller conveying forces to the sheet (P) than the conveying forces to the sheet (P) in the first stiffening rollers (34a).

Abstract: An image forming apparatus (100) includes a discharge section (210), a paper receiving tray (93), a first detecting section (211), a lever (220), a second detecting section (230) and a decision section (240). The first detecting section (211) is disposed in the discharge section (210), and detects a paper jam. The second detecting section (230) detects a swinging state of the lever (220) from a first position at which the lever (220) is not in the process of receiving an action of the paper sheet to a second position. The decision section (240) judges an occurrence factor in a paper jam to be a user-induced factor when the second detecting section (230) detects a state in which the lever is at the first position in a state where the first detecting section (211) detects the paper jam.

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: A sheet conveying device (30) includes a plurality of first conveyance rollers (31) and a plurality of second conveyance rollers (32). The sheet conveying device (30) includes stiffening rollers (34). The stiffening rollers (34) are disposed coaxially with at least one conveyance rollers (32) among the first and second conveyance rollers (31) and (32), and have diameters larger than diameters of the conveyance rollers (32). The stiffening rollers (34) includes first stiffening rollers (34a), which apply conveying forces to a sheet (P), and second stiffening rollers (34b), which apply smaller conveying forces to the sheet (P) than the conveying forces to the sheet (P) in the first stiffening rollers (34a).

Abstract: A sheet sorter includes a sheet discharge tray, a sheet conveyance unit, and a sheet pressing guide. The sheet conveyance unit is configured to convey sheets in a conveyance direction and configured to be shifted in a shift direction along a sheet plane and in a shift direction that intersects the conveyance direction, so as to sort the sheets loaded onto the sheet discharge tray from the sheet conveyance unit. The sheet pressing guide is configured to contact and press the sheets, configured to move together with the sheet conveyance unit in conjunction with the sheet conveyance unit moving in the shift direction, and configured to contact a topmost sheet among the sheets loaded on the sheet discharge tray only at a downstream edge of the topmost sheet in the conveyance direction.

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 sheet sorter includes a sheet discharge tray, a sheet conveyance unit, and a sheet pressing guide. The sheet conveyance unit is configured to convey sheets in a conveyance direction and configured to be shifted in a shift direction along a sheet plane and in a shift direction that intersects the conveyance direction, so as to sort the sheets loaded onto the sheet discharge tray from the sheet conveyance unit. The sheet pressing guide is configured to contact and press the sheets, configured to move together with the sheet conveyance unit in conjunction with the sheet conveyance unit moving in the shift direction, and configured to contact a topmost sheet among the sheets loaded on the sheet discharge tray only at a downstream edge of the topmost sheet in the conveyance direction.

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: 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: 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.