A sheet folding apparatus for folding a sheet is provided with a hold member that holds a transported sheet in a substantially cylindrical shape, a shift member that presses the outer circumferential surface of the sheet of the substantially cylindrical shape held by the hold member to make a substantially flat shape, and a discharge section that further presses the sheet made the substantially flat shape by the shift member, while discharging in a direction crossing a transport direction. By this means, it is possible to provide a relatively compact sheet folding apparatus.

A recording medium conveyor includable to an image forming apparatus includes a driving source, a first rotary unit, and a second rotary unit. The first rotary unit includes a driving gear, a driving shaft rotating with the driving gear, and multiple driving rotary bodies disposed on the driving shaft. The second rotary unit disposed facing the first rotary unit includes a driven gear meshed with the driving gear, a driven shaft, multiple driven rotary bodies disposed on the driven shaft, and multiple stiffening rotary bodies disposed between two of the multiple driven rotary bodies and having a diameter greater than an outer diameter of the multiple driven rotary bodies. A gear ratio between the driving gear and the driven gear is adjusted such that a peripheral speed of the multiple driving rotary bodies is equal to a peripheral speed of the multiple stiffening rotary bodies.

A sheet folding device includes two rollers, a blade, two parallel pins, and two gears. The first and second parallel pins are passed through first and second pin through-holes penetrating through first and second shaft portions in a direction perpendicular to a longitudinal direction of the shaft portions. The first and second gears have first and second shaft through-holes through which the first and second shaft portions are passed, and first and second grooves in which the first and second parallel pins are inserted, respectively. Projection portions formed on inner side wall of the second groove and projecting from both sides of the second shaft portion cause the second parallel pin to closely contact a side wall that is, in the second groove, opposite to the projection portions, and cause the second parallel pin to closely contact a portion of the second pin through-hole.

A medium feeding unit that is configure to be mounted to an image forming apparatus provided with an image forming unit and feeds a medium to the image forming unit includes a medium introducing part that introduces the medium to the image forming unit and a medium holding part that holds the medium at a feeding position from which the medium is fed to the image forming unit. The medium holding part is configured to be positioned at one of at least two different feeding positions relative to the medium introducing part.

A sheet material feeding apparatus includes a first roll 106, and a second roll 108 arranged vertically below first roll 106, to feed a sheet material clamped between the first roll 106 and the second roll 108. The sheet material feeding apparatus further includes a first motor 102 provided with a rotatable first motor shaft 104 coupled to the first roll 106, and a second motor 103 provided with a rotatable second motor shaft 105 coupled to the second roll 108. The first motor shaft 104 and the second motor shaft 105 rotate at substantially the same rotation speed to allow the first roll 106 and the second roll 108 to rotate in synchronization with each other.

A document feeding device includes a document conveyance path for conveying a document to a first document reading position and a second document reading position for reading an image. Further, the document conveyance path includes a curved conveyance path. The document feeding device includes a document feeding roller that feeds the document to the curved conveyance path and a large-diameter conveying roller disposed on an inner side of the curved conveyance path and having a diameter larger than a diameter of the document feeding roller. A document conveyance speed of the large-diameter conveying roller is higher than a document conveyance speed of the document feeding roller.

Example implementations provide a controller comprising circuitry to align a substrate; the controller comprising: circuitry to control varying the tension of an unspooled portion of the substrate between a spool bearing the substrate and a pinch roller; said circuitry comprising circuitry to control varying the pinch load exerted by the pinch roller on the unspooled portion of the substrate.

A medium conveyance device includes: a plurality of roller pairs arranged in a width direction of a recording medium, the plurality of roller pairs including at least two end-side roller pairs respectively located near two ends of the recording medium in the width direction and at least one center-side roller pair located near a center of the recording medium in the width direction, the plurality of roller pairs each including a pair of rollers that convey the recording medium while nipping the recording medium and are individually contactable with and separable from each other; and a contact and separation mechanism that moves a first roller of the pair of rollers of the at least one center-side roller pair in a thickness direction of the recording medium or moves a first roller of the pair of rollers of each of the at least two end-side roller pairs in the thickness direction of the recording medium, to make a difference in separation timing.