According to one embodiment, an image forming apparatus includes a support shaft, a connecting member, and a detachable member. The support shaft extends in a first direction. The support shaft includes a protrusion. The protrusion protrudes in a second direction orthogonal to the first direction. The connecting member is formed of an elastic material. The connecting member interposes the protrusion therebetween. The connecting member is connected to the support shaft to surround an outer periphery of the support shaft. The detachable member is detachably connected to the support shaft via the connecting member.

A sheet feeding device includes a stacking member, a feeding unit, and a detachable separation unit. The feeding unit feeds sheets stacked from the stacking member. The separation unit separates the fed sheets one by one. The separation unit includes a rotating member to abut and separate from the feeding unit and to rotate, a biasing member to bias the rotating member toward the feeding unit, and an engaged member to be engaged with an engagement member included in the sheet feeding device. The engagement member can move to a first position where the engagement member is engaged with the engaged member, and a second position away from the engaged member. Where the engagement member moves from the first to the second position when the separation unit is attached to the sheet feeding device, the separation unit moves in a detachment direction using the biasing member.

According to an embodiment, a sheet feeding mechanism includes a first elastic body. The first elastic body blocks a first reference line and a second reference line. The first elastic body has a first angle formed between the first elastic body and the first reference line, the first angle being an acute angle. The first reference line is a reference line along a take-out direction by the first roller. The second reference line is a reference line connecting a nip between the second roller and the third roller and a contact position of the first roller and a sheet.

A direction orthogonal to an attachment/detachment direction is defined as a first direction and a direction orthogonal to the attachment/detachment direction and to the first direction is defined as a second direction. A sheet feeding cassette includes a contact portion that comes into contact with a roller separation mechanism unit, the contact portion including a first inclined surface inclined to extend along a straight line including a component in the attachment/detachment direction and a component in the first direction. The roller separation mechanism unit includes a contacted portion that comes into contact with the contact portion, the contacted portion including a second inclined surface inclined to extend along a straight line including a component in the attachment/detachment direction and a component in the second direction.

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, a sheet feed device includes a first roller, a second roller, a torque limiter, a holder, and a driving unit. The first roller conveys a sheet in a first direction while being in contact with a first surface of the sheet. The second roller faces the first roller and is in contact with a second surface which is a back side of the first surface of the sheet in a state of sandwiching the sheet between the second roller and the first roller. The torque limiter imparts an anti-torque to the second roller in order to generate a force on the second surface in a direction opposite to the first direction. The holder rotatably supports the second roller. The driving unit moves the holder and biases the holder toward the first roller.

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.

A feeding device includes a stacked portion on which materials to be fed are stacked, a feeding roller that feeds the materials to be fed stacked on the stacked portion, a cam that performs first rotation in a state of being in contact with a mounting member on which the feeding roller is mounted and raises the feeding roller, an elastic member that lowers the raised feeding roller to the stacked portion while causing the cam that is in contact with the mounting member to perform second rotation with an elastic force acting on the mounting member, and an applying unit that applies a rotation resistance to the cam performing the second rotation.

According to an embodiment, a sheet feeding mechanism includes a first elastic body. The first elastic body blocks a first reference line and a second reference line. The first elastic body has a first angle formed between the first elastic body and the first reference line, the first angle being an acute angle. The first reference line is a reference line along a take-out direction by the first roller. The second reference line is a reference line connecting a nip between the second roller and the third roller and a contact position of the first roller and a sheet.

An original reading apparatus includes a reading unit, a pick-up roller, a feed roller, a conveyance roller, a conveyance motor, a clutch, and a controller unit to control the clutch and the conveyance motor such that the pick-up roller and the feed roller that receive a driving force from the conveyance motor rotate at a given rotation speed. The rotation speed is set to a first speed when reading an original having a first size at a first resolution, to a second speed higher than the first speed when reading an original having the first size at a second resolution lower than the first resolution, and to a third speed lower than the second speed, regardless of designation of the reading resolution, when reading an original having a second size smaller than the first size.