A thickness detector includes a rotator having different shape marks, disposed at different positions in a rotation direction; an opposing member disposed opposite the rotator; a detector to detect and output a displacement amount of the rotator or the opposing member in a sheet thickness direction; and a controller. The controller is configured to acquire first output values for one rotation from the detector, in a state without sheet; determine, based on a value output from the detector, whether one of the plurality of marks is detected in a state with the sheet held; acquire a predetermined number of second output values after one of the marks is detected; extract, from the first output values, values corresponding to the second output values, based on the value corresponding to the detected mark; and calculate a sheet thickness based on the second output values and the extracted first output values.

A paper feed roller that can prevent paper sheet transport failure caused by accumulation of paper powder for a long period of time is provide. This paper feed roller includes a shaft body and an elastic body layer formed on the outer periphery of the shaft body. Unevenness are formed by protrusions on the circumferential surface of the elastic body layer. The protrusions are arranged on the circumferential surface of the elastic body layer in a direction different from an axial direction. The gap between a row of protrusions which extends in the direction different from the axial direction and a row of protrusions which is parallel to the row of protrusions is a continuous recess, i.e., a groove, and the width of the groove is greater than the distance between the protrusions in the row of protrusions which extends in the direction different from the axial direction.

Provided herein may be a pick-up roller with a front-edge alignment element and a media separation apparatus using the pick-up roller. The pick-up roller may include a pick-up element configured to pick up and transfer a media sheet, and the front-edge alignment element provided at a position opposite to the pick-up element. During a process of picking up a stacked media sheet and transferring it into a space between a feed roller and a separation roller unit, the front-edge alignment element may align in advance a front edge of a media sheet disposed subsequent to the medial sheet that is being transferred, to a position of the entrance between the feed roller and the separation roller unit, and thereafter, the pick-up element may pick up the media sheet aligned by the front-edge alignment element and transfer it into the space between the feed roller and the separation roller unit.

A sheet processing device for pressing a fold line formed in a sheet, the sheet processing device comprises a pressing portion configured to press a sheet while rotating about a rotation axis. The pressing portion includes a pressing unit having a projecting shape, disposed over a predetermined range in a direction of the rotation axis to have a position in a rotation direction about the rotation axis changed according to the direction of the rotation axis, and an impact absorbing member provided at a part of the pressing unit of the pressing portion, abutting on the sheet at first in the rotation direction of the pressing portion, the impact absorbing member configured to reduce impact upon abutting on the sheet.

A rotary feeding member for feeding a sheet is provided with a plurality of protruding portions, a plurality of first recessed portions and a plurality of second recessed portions on a cross-section perpendicular to a width direction of the rotary feeding member. The plurality of protruding portions constituting an outer circumferential surface of the rotary feeding member to be in contact with the sheet. Each of the plurality of first recessed portions and the plurality of second recessed portions is provided between any adjacent two of the plurality of protruding portions in the rotating direction. The plurality of first recessed portions are recessed to a first depth with respect to the outer circumferential surface, and the plurality of second recessed portions are recessed to a second depth smaller than the first depth with respect to the outer circumferential surface.

A paper feed roller of the present invention comprises a roller body 2 integrally formed of elastic material in a cylindrical shape in which a plurality of protruding lines 6 are disposed on a peripheral surface 5 at even intervals, wherein the roller body 2 is formed so that crest portions 6a and trough portions 6b are continuously provided in a circumferential direction, an opening angle is equal to or more than 2 and is equal to or less than 8, a radial height h of the protruding line is equal to or more than 0.051 mm and is equal to or less than 0.1 mm, and a curvature radius r1 at a shoulder is equal to or more than 0.55 mm.

A feeding roller for a document conveying apparatus includes a plurality of groove portions arranged with a regular interval in a width direction of the feeding roller on a surface of the feeding roller, and a projection portion provided between each pair of adjacent groove portions to scrape off paper particles on the external peripheral. The projection portion has a regular pattern extending in the width direction of the feeding roller.

A discharge device which discharges a sheet includes: a driving shaft which is driven to rotate by a driving source; a plurality of driving rotating members which is provided on the driving shaft; a rotating member which is provided on the driving shaft, has a larger outside diameter than an outside diameter of the driving rotating member, is formed by joining at least two divided components, and includes stepped portions that protrude, to a larger extent, in a radial direction in boundary portions of the at least two components on upstream sides of a rotation direction of the rotating member than on downstream sides thereof; and follower rotating members which are pressed against the driving rotating members.

A sheet processing device for pressing a fold line formed in a sheet, the sheet processing device comprises a pressing portion configured to press a sheet while rotating about a rotation axis. The pressing portion includes a pressing unit having a projecting shape, disposed over a predetermined range in a direction of the rotation axis to have a position in a rotation direction about the rotation axis changed according to the direction of the rotation axis, and an impact absorbing member provided at a part of the pressing unit of the pressing portion, abutting on the sheet at first in the rotation direction of the pressing portion, the impact absorbing member configured to reduce impact upon abutting on the sheet.

A sheet processing apparatus is configured to press a fold line that is formed on a sheet. The sheet processing apparatus includes: a sheet supporting unit configured to support the sheet in a pressing direction for pressing the fold line; a pressing unit configured to press the fold line that is formed on the sheet that is supported by the sheet supporting unit; and a pressing-force generating unit configured to generate a pressing force for pressing the sheet supporting unit against the pressing unit at a central part in a direction along which the fold line is formed.