An optical sensor includes a light emitting unit configured to emit and output light. a light receiving unit configured to receive light, a substrate on which the light emitting unit and the light receiving unit are mounted, an electrically conductive pattern including a land to be electrically connected to an electrode of the light emitting unit, a resist arranged as a layer above the electrically conductive pattern or the substrate, a light shielding layer provided as a layer above the resist, and a light shielding region formed by a portion of the land and a portion of the light shielding layer overlapping in the direction of the normal of a mounting surface of the substrate, to shield stray light directed towards the substrate from the light emitting unit, the light shielding region.

Method for controlling a sheet feeding device (1) comprising an elevator (2) for a stack of sheets, and an air supply system (3) configured to supply and direct one of more air streams towards an upper region (4) of the sheet feeding device for floating a plurality of upper sheets of the stack of sheets, wherein the elevator comprises a vertically movable support (5) for supporting the stack of sheets from below, wherein the sheet feeding device comprises an optical sensor (6) positioned adjacent the floated sheets for measuring light reflected from the floated sheets at a plurality of different heights, wherein the method comprises the steps of: continuously deriving from the optical sensor a density reading (DR) indicating the density of sheets floated, continuously deriving an average density (AD) based on a plurality of density readings, continuously deriving an upper density limit (UDL) based on the average density multiplied by a predetermined upper density limit factor (UDLF), continuously deriving a lower density limit (LDL) based on the average density multiplied by a predetermined lower density limit factor (LDLF), adjusting a first operating parameter (OP) of the sheet feeding device should the density reading exceed the upper density limit, wherein the adjustment of the first operating parameter is such as to decrease the density of floated sheets, and adjusting the first operating parameter of the sheet feeding device should the density reading subceed the lower density limit, wherein the adjustment of the first operating parameter is such as to increase the density of floated sheets. Also, a sheet feeding device connected to a controller configured to operate according to this method.

A medium conveying apparatus includes a first optical sensor located on an upper part of the housing and in a central part of the housing in a direction perpendicular to a medium conveying direction, a second optical sensor located on an upper part of the housing and on a side of the first optical sensor in the direction perpendicular to the medium conveying direction, and a processor to detect a folding of a medium based on the first signal or the second signal, and stop feeding of the medium by the feed roller in accordance with a detection result of the folding of the medium. The first light emitter emits first light toward a downstream side of the medium in the medium conveying direction, and the second light emitter emits second light toward an upstream side of the medium in the medium conveying direction.

A sheet stacker includes a housing, a fence, a first distance measurement sensor, and a second distance measurement sensor. The fence is movable in a fence moving direction on the housing and is configured to regulate a position of an end of a sheet. The first distance measurement sensor is configured to measure a distance between the fence and a first portion of the housing, the first portion being on one side of the housing with respect to the fence in the fence moving direction. The second distance measurement sensor is configured to measure a distance between the fence and a second portion of the housing, the second portion being on another side of the housing with respect to the fence in the fence moving direction.

A sheet feeding device feeds a sheet in a feed direction. The sheet feeding device includes a loading portion, a feeler, and a first detection sensor. The sheet is to be placed on the loading portion. The feeler rotates from a reference position to a pushed position around a support shaft in response to a push by a downstream end of the sheet, which is placed on the loading portion, in the feeding direction. The first detection sensor detects a rotation of the feeler from one of the reference position and the pushed position to the other of the reference position and the pushed position. The loading portion includes a second detection sensor to detect a state in which the sheet is placed on the loading portion.

A detection sensor includes: a single light-emitting element that radiates light onto a conveyed material; and multiple light-receiving elements that receive interference light including the light that is scattered at a surface of the conveyed material and the light that is scattered inside the conveyed material.

Various embodiments disclose a method of detecting a media jam in a printer. The method includes causing a sensor unit of the printer to generate a sensor signal indicative of a reflectance characteristic associated with a surface of a roller of the printer. Further, the method includes receiving the sensor signal from the sensor unit of the printer and comparing the reflectance characteristic to a threshold reflectance characteristic associated with the roller. Furthermore, in response to the comparison, the method includes generating an output signal to indicate whether the media jam has occurred. For example, a first output signal indicates unsuccessful passage of a media along a media path of the printer, when the reflectance characteristic exceeds the threshold reflectance characteristic and a second output signal indicates successful passage of the media along the media path, when the reflectance characteristic is equal to or below the threshold reflectance characteristic.

A medium feeding device includes a medium placing portion, a feeding roller that feeds paper, a medium movement detecting portion that is positioned on a placing region of the paper of the medium placing portion in a medium feeding direction and is capable of detecting movement of the paper being fed in a width direction intersecting the medium feeding direction, and a controller that stops feeding of the paper in a case in which a physical quantity relating to movement of paper in the width direction exceeds a predetermined threshold based on a detected result by the medium movement detecting portion.

A roll sheet with a continuous sheet wound in a roll form is rotated in a forward direction to supply the sheet to a printing unit. A sensor whose output is changed in accordance with a distance between the sensor and the sheet is used. A rotation direction of the roll sheet is switched from an opposite direction to the forward direction on the basis of the output of the sensor during rotation of the roll sheet in the opposite direction.

A medium feeding device includes a medium placing portion, a feeding roller that feeds paper, a medium movement detecting portion that is positioned on a placing region of the paper of the medium placing portion in a medium feeding direction and is capable of detecting movement of the paper being fed in a width direction intersecting the medium feeding direction, and a controller that stops feeding of the paper in a case in which a physical quantity relating to movement of paper in the width direction exceeds a predetermined threshold based on a detected result by the medium movement detecting portion.