Abstract: A rotation amount detecting device for a rotation body includes: a first rotation body having a first surface; a second rotation body having a second surface formed of a material different from that of the first surface and contacting the first surface, and rotating with rotation of the first rotation body; a first support member rotatably supporting the first rotation body at a first position and supporting thereof to be swingable around a first axis at a position different from the first position; a second support member rotatably supporting the second rotation body at a second position and supporting thereof to be swingable around a second axis provided at a position different from the second position, the second axis being the first axis or an axis in the first support member other than the first axis; and a detector that detects a rotation amount of the second rotation body.

Abstract: A length measurement apparatus including: a measurement portion that measures a sheet length based on a rotational amount of a length measurement roll for a first detection period in which first and third sensors detect the sheet, and a sheet length based on a rotational amount of the length measurement roll for a second detection period in which the second sensor and any one of the first and third sensors detect the sheet, the any one of the first and third sensors being disposed at a position opposite to the second sensor via the length measurement roll; and a whole length calculation portion that selects the sheet length nearer to integral multiples of the circumference length of the length measurement roll from the sheet lengths measured for the first and second detection periods, and calculates the whole length of the sheet by using the selected sheet length.

Abstract: A sheet length measurement apparatus including: a rotating member that comes in contact with a recording sheet conveyed on a conveying path, and rotates along with the conveyance of the recording sheet; a rotation amount detector that detects a rotational amount of the rotating member; a fixing support member that fixedly supports an rotating shaft of the rotating member at a fixed position; an opposed member that is disposed opposite to the rotating member so as to hold the recording sheet between the rotating member and the opposed member, the opposed member being disposed so that the rotating member rotates along with the conveyance of the recording sheet; and a support member that supports the opposed member in a movable state in a direction to separate from or come in contact with a surface of the recording sheet.

Abstract: A sheet length measuring apparatus that includes: a rotating body that rotates in contact with a sheet delivered through a delivery path; detecting units that are located upstream and downstream of the rotating body respectively, and detect a position of the sheet delivered through the delivery path; a delivery unit that is located in at least one of positions between the detecting unit located upstream and the rotating body, and between the detecting unit located downstream and the rotating body, and delivers the sheet on the delivery path; and a rotation amount detecting unit that detects a rotation amount of the rotating body with using a period when the sheet is detected by the detecting units respectively located upstream and downstream of the rotating body as a measurement period.

Abstract: An apparatus for measuring a length of a recording material, includes: a rotating member that rotates while contacting a conveyed recording material; a detecting section that detects a rotation amount of the rotating member; an information obtaining section that obtains at least one of information of an image formed on the recording material and information of the recording material; and a calculating section that calculates a length of the recording material in a direction of the conveyance, based on an output from the detecting section and the information obtained by the information obtaining section.

Abstract: A measuring device, wherein a feed-out member feeds out an uppermost one of plural sheet-shaped materials stacked on a base by rotating in contact with the uppermost sheet-shaped material, has a detector that detects a force imparted to the base and the sheet-shaped materials not in contact with the feed-out member, the force being generated by feeding-out the uppermost sheet-shaped material.

Abstract: A position detection apparatus includes: a moving member in contact with a detection object that moves following movement of the detection object; and a support member that rotatably supports the moving member; a detection unit that detects a positional change of the moving member, the moving member being acted on by a first force as a force to press the moving member against the detection object, a second force as a force to press the moving member substantially in a direction of a rotation shaft of the moving member, and a third force as a force to press the moving member in a direction substantially orthogonal to the direction of the rotation shaft of the moving member.

Abstract: A recording medium thickness measuring apparatus includes: an output value detection unit that detects an output value which fluctuates in accordance with thickness of a recording medium passing through a predetermined position of a transport path; and a calculation unit that calculates the thickness of the recording medium based on a first output value detected by the output value detection unit before passage of the recording medium and after passage of an immediately preceding recording medium in the predetermined position of the transport path, and a second output value detected by the output value detection unit while the recording medium is passing through the predetermined position.

Abstract: A sheet feed device includes an air flow generating part that generates an air flow for floating a sheet; a feed member that feeds a sheet by rotating, while applying a load to the top one of sheets stacked; and a transport condition sensing unit that is positioned not to obstruct an air flow generated by the air flow generating part and senses a transport condition of a sheet fed by the feed member.

Abstract: A sheet feeding apparatus includes: a multiple-feed detecting section that detects recording sheets to be transported by plural rolls in a direction; a separating section that separates an uppermost sheet of the recording sheets from the other; a slippage detecting section that detects a slippage of the uppermost recording sheet with respect to a roll; and a transporting-speed reduction suppressing section that suppresses a transporting-speed of the uppermost recording sheet from reducing from a value, the separation section including: a transporting roll that transports recording sheets in a transporting direction; and a separation roll that is placed to be opposed to and to be press-contacted with the transporting roll through a recording sheet, the transporting-speed reduction suppressing section changing a separation torque of the separation roll according based on a result of detection by the multiple-feed detecting section and a result of detection by the slippage detecting section.

Abstract: A measuring device, wherein a feed-out member feeds out an uppermost one of plural sheet-shaped materials stacked on a base by rotating in contact with the uppermost sheet-shaped material, has a detector that detects a force imparted to the base and the sheet-shaped materials not in contact with the feed-out member, the force being generated by feeding-out the uppermost sheet-shaped material.

Abstract: A sheet feeding apparatus includes: a multiple-feed detecting section that detects recording sheets to be transported by plural rolls in a direction; a separating section that separates an uppermost sheet of the recording sheets from the other; a slippage detecting section that detects a slippage of the uppermost recording sheet with respect to a roll; and a transporting-speed reduction suppressing section that suppresses a transporting-speed of the uppermost recording sheet from reducing from a value, the separation section including: a transporting roll that transports recording sheets in a transporting direction; and a separation roll that is placed to be opposed to and to be press-contacted with the transporting roll through a recording sheet, the transporting-speed reduction suppressing section changing a separation torque of the separation roll according based on a result of detection by the multiple-feed detecting section and a result of detection by the slippage detecting section.

Abstract: A recording medium supply apparatus includes: a conveyance member that conveys a recording medium; a retard member, in contact with the conveyance member, that forms a contact portion between the conveyance member and the retard member and retards the recording medium by holding the recording medium in the contact portion; and a buckling prevention unit, configured to contact with the recording medium on the upstream side of the contact portion between the conveyance member and the retard member in a conveyance direction of the recording medium, that prevents buckling of the recording medium in the conveyance direction.

Abstract: An image formation apparatus includes: a toner image formation section that forms a toner image on a recording medium; a fixing device that fixes the toner image; a first roller provided downstream from the fixing device in a transport direction of the recording medium, the first roller coming in contact with a first side of the recording medium and transporting the recording medium; and a second roller abutting the first roller, the second roller coming in contact with a second side of the recording medium opposite to the first side and transporting the recording medium. The solubility parameter on a surface of the first roller is different from the solubility parameter on a surface of the second roller.

Abstract: In a recording sheet conveying device comprising: a dielectric sheet which moves at a predetermined speed while electrostatically retaining a recording sheet on the outer surface thereof; a charger positioned on the side of the inner surface of the dielectric sheet, to induce electrostatic attraction forces between the dielectric sheet and the recording sheet; and a deflector roll having an electrically conductive layer as an outer surface thereof, the deflector roll being confronted with the charger and adapted to push the recording sheet against the dielectric sheet, the number of electric charges provided by the charger is so adjusted that electrostatic attraction forces acting on the rear end portion of the recording sheet are weaker than those acting on the front end portion of the recording sheet, whereby the recording sheet is prevented from being wrinkled when electrostatically retained on the dielectric sheet.