Provided are: a sheet feed device that is capable of suppressing the occurrence of a sheet feeding fault by changing the pressing contact force of a retard roller against a feed roller; and an image formation device equipped with the same. This sheet feed unit (50) is provided with: a pickup roller (29); a feed roller (31); a retard roller (32); a holding member (40) that holds the retard roller (32); a first biasing member (42) that biases the holding member (40); and a pressing contact force changing mechanism (60) that changes the pressing contact force of the retard roller (32) against the feed roller (31). The pressing contact force changing mechanism (60) has: a rotary shaft (61) disposed parallel to the axial direction of the retard roller (32); a cam member (70) that rotates with the rotary shaft (61); and a movable member (80) that contacts the cam member (70), moves in the axial direction in conjunction with the rotation of the cam member (70), and changes the biasing force generated by the first biasing member (42).

According to one embodiment, a paper feeding device includes a paper feeding roller and a separation roller. The paper feeding roller and the separation roller are arranged in a parallel direction. The paper feeding roller and the separation roller interpose a sheet. The paper feeding device includes a paper feeding roller, a separation roller, a shaft, a holder, and a rotation stopping portion. The paper feeding roller is configured to convey the sheet in a conveyance direction. The separation roller is configured to be pressed against the paper feeding roller. The shaft is configured to rotatably support the separation roller via a torque limiter. The holder is configured to include a supporting portion. The supporting portion is provided with a first guide surface and a second guide surface facing each other and extending in the parallel direction. The rotation stopping portion is configured to be attached to the shaft. The rotation stopping portion is configured to be inserted between the first guide surface and the second guide surface. The rotation stopping portion is configured to include a first sliding surface and a second sliding surface. The first sliding surface faces the first guide surface on the paper feeding roller side of the parallel direction and a downstream side of the conveyance direction with respect to a rotation axis of the separation roller. The second sliding surface faces the second guide surface on an opposite side of the paper feeding roller of the parallel direction and an upstream side of the conveyance direction with respect to the rotation axis of the separation roller.

According to one embodiment, there is provided an image processing apparatus including a sheet storage unit, a pickup roller, a paper feed roller, a separation roller, a roller drive unit, a roller pressing unit, and a drive control unit. The pickup roller picks up a sheet from the sheet storage unit. The paper feed roller conveys the sheet picked up by the pickup roller. The separation roller is disposed to face the paper feed roller. The roller drive unit drives the separation roller. The roller pressing unit presses the separation roller against the paper feed roller. The drive control unit controls the roller drive unit so as to generate a conveying force for conveying the sheet and a returning force for pushing the sheet back in a direction opposite to a conveyance direction.

A sheet feeding apparatus includes a sheet stacker to stack at least one sheet; a sheet feed roller disposed at one side of the sheet stacker and to feed a sheet fed from the sheet stacker; a multi-feed prevention roller disposed to face the sheet feed roller and to prevent multi-feed of the sheet fed from the sheet stacker; a magnetic torque limiter disposed coaxially with the multi-feed prevention roller; a hall sensor disposed at one side of the magnetic torque limiter and to detect rotation of the magnetic torque limiter; and a controller configured to rotate the sheet feed roller in a state in which the sheet feed roller and the multi-feed prevention roller are in contact with each other without a sheet and to identify a lifetime of the multi-feed prevention roller by using a signal output from the hall sensor.

The disclosure relates to a feeding apparatus capable of feeding media sheet. The feeding apparatus includes first feeding assembly comprising first mount frame, first roller and stopper. The stopper is pivotally connected to the first mount frame and movable with the first roller, the stopper has a covering portion configured to stop the media sheet, the first roller is located in the first mount frame and is movable along a straight path; while the stopper is pressing against the first roller and the first roller is moving along the straight path, the stopper is moved with the first roller so that the covering portion of the stopper is moved close to or away from the straight path.

A rubber composition for a paper feed roll contains at least a polymer component and a softener, has a 30% Mod (−40° C.) of less than or equal to 0.94 MPa, the 30% Mod (−40° C.) representing a modulus in 30% elongation at −40° C., and has an E1 (22° C.)/number of parts by mass of softener of greater than or equal to 0.008 MPa/phr, the E1 (22° C.)/number of parts by mass of softener representing a value of a dynamic modulus of elasticity at 22° C. E1 (22° C.) in temperature variance measurement of dynamic viscoelasticity, divided by the number of parts by mass of the softener relative to 100 parts by mass of the polymer component. These configurations provide a rubber composition for a paper feed roll and a paper feed roll that are excellent in maintainability of a coefficient of friction and wear resistance.

A sheet conveyance apparatus includes a storage unit storing a sheet, a conveyance member to convey a sheet, a support shaft portion, and a separation unit. The support shaft portion has one end fixed to a main body of the sheet conveyance apparatus and the other end as a free end that is not fixed to the main body. The separation unit pinches and conveys a sheet with the conveyance member and separates a plurality of sheets stored in and fed from the storage unit one by one. The separation unit includes a separation member that is supported by the support shaft portion and rotatable with the support shaft portion, and a holding member to hold the separation member. By moving the holding member in an axial direction of the support shaft portion, the separation unit is removed from the apparatus with the holding member holding the separation member.

A sheet conveyor includes a drive roller, a retard roller forming a nip with the drive roller, a first torque limiter disposed coaxially with the retard roller and communicating with the retard roller, a first gear disposed coaxially with the retard roller, a drive train including a plurality of gears for receiving a driving force from the first gear, a second torque limiter, and an arm member including a contact portion located downstream of the drive roller in the conveyance direction. The arm member is movable between a first arm position to allow transmission of the driving force to the second torque limiter and a second arm position to interrupt transmission of the driving force to the second torque limiter. The arm member is configured to, as the sheet conveyed by the drive roller contacts the contact portion, move from the first arm position to the second arm position.

A document conveyance apparatus includes a feed roller, a first and a second conveyance rollers, a conveyance shaft, an arm portion rotatably moving the feed roller to a standby position to a feeding position, a transmission portion transmitting rotation of the conveyance roller shaft to the arm portion, and a torque limiter. The feed roller and the first conveyance roller rotate in a conveyance direction when the conveyance roller shaft rotates in a first direction, and the feed roller moves from a feeding position to a standby position when the conveyance roller shaft rotates in a second direction. When a document fed by the second conveyance roller moves through a nip portion, a transmission portion does not transmit rotation of the first conveyance roller rotated in the second direction by the separation roller to an arm portion by operation of the torque limiter.

An object of the present disclosure is to provide a printing apparatus in which it is possible to easily clean the surface of a feeding roller and a separation roller by using a damp cloth or the like. One embodiment of the present invention is a printing apparatus including: a feeding roller that feeds a printing medium; a separation roller capable of selectively taking a state where a separating force that separates a plurality of printing media conveyed by the feeding roller one by one has occurred and a state where the separating force has not occurred at a position at which the separation roller is in pressure contact with the feeding roller; and a control unit configured to perform control to bring about a standby state where transmission of a driving force between a driving source of the feeding roller and the feeding roller is shut off in a state where the separating force has not occurred and the feeding roller and the separation roller abut each other.