Sharp Kabushiki Kaisha Corporation

Norichika Katsura

Masaharu Kimura

Masahiko Fujita

Tadasu Taniguchi

Yasuaki Fukada

Masaya Asakawa

Yoshiyuki Kobayashi

Yasuhiro Takai

Kohji Aoki

Masatsugu Ohishi

Yoshiteru Kikuchi

Yasunobu Ohkawa

Haruhisa Furumoto

Toshiki Ohgita

Yoshinori Shiraishi

Shinichi Azumi

Shinichiroh Hiraoka

Michihiro Yamashita

Tatsuya Ogawa

Yasuaki Fukuda

Rei Nakamura

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.

Sheet feeding device and image forming apparatus

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

Image forming apparatus that determines user-induced paper jam

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.

Paper conveying device, image forming apparatus provided with the device and paper conveying method

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

Sheet conveying device and image forming apparatus with the same

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.

Recording paper conveying device, document feeding device and image forming apparatus including these devices

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.

Sheet detection apparatus and image forming apparatus

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.

Sheet sorter and image forming apparatus

In a sheet transport apparatus, coiled springsare fitted in and supported by recess portionsat a bottom faceof a support frameand recess portionsat an upper faceof an inner guide. In other words, most of the portions of the coiled springare enclosed inside the recess portionsof the support frameand the recess portionsof the inner guide, and covered and hidden by side wallsof the recess portionsand side wallsof the recess portions

Sheet transport apparatus

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.

Paper transport path of image forming apparatus

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.

Sheet feeding device

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.

Sheet transport apparatus and image forming apparatus provided with the same

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.

Sheet feeding apparatus with mechanism for detecting sheet feeding state and sheet feeding method

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.

Feeding device and image forming apparatus

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.

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Tenri, Japan

Norichika Katsura