An apparatus and method for determining sheet material edges on a surface including a sensor configured to detect an outer edge and a usable edge of the sheet material and a controller in communication with the sensor. The sensor comprises a first color optical sensor producing a first signal representing a first physical attribute of the sheet material and a second color optical sensor producing a second signal representing a second physical attribute of the sheet material. The controller comprises a processor, a memory, and a communications adapter, controls dispensing and spreading of the sheet material for detection by the sensor, and signals to a user a presence of the usable edge in the sheet material upon detection by the sensor.

A paper sheet post-processing device includes a processing tray, an aligning member that aligns paper sheets on the processing tray, a swingable holder that supports the aligning member, a swinging mechanism that causes the holder to swing, and a control unit that controls the swinging mechanism. The swinging mechanism includes a rotation shaft inserted into a shaft insertion portion of the holder with play in a rotation direction. The control unit controls the rotation shaft to rotate and stop at a predetermined rotation angle position corresponding to a stack height of the sheets stacked on the processing tray, so that the holder is disposed at a contact position. At the contact position, the holder is allowed to swing in a retracting direction with respect to the rotation shaft within a predetermined play range. The play range is set to be larger in proportion to the stack height of the sheets.

A post-processing apparatus includes a post-processing unit configured to receive sheets from an image forming apparatus, perform processing on the received sheets, and then discharge the processed sheets through a discharge port. A sensor is configured to detect a presence of an object at the discharge port. The sensor includes a first light emitter on a first side of the discharge port that is positioned to emit a light across a width of the discharge port, a reflector on a second side of the discharge port opposite the first side in a first direction, and a first light receiver positioned to receive light of the first light emitter from the reflector. A controller is configured to terminate the processing on the received sheets by the post-processing unit when the sensor detects the presence of the object at the discharge port.

A post-processing apparatus includes a post-processing unit configured to receive sheets from an image forming apparatus, perform processing on the received sheets, and then discharge the processed sheets through a discharge port. A sensor is configured to detect a presence of an object at the discharge port. The sensor includes a first light emitter on a first side of the discharge port that is positioned to emit a light across a width of the discharge port, a reflector on a second side of the discharge port opposite the first side in a first direction, and a first light receiver positioned to receive light of the first light emitter from the reflector. A controller is configured to terminate the processing on the received sheets by the post-processing unit when the sensor detects the presence of the object at the discharge port.

Provided is a recording medium detection device which prevents the decline in productivity. The recording medium detection device comprises a first detecting section and a second detecting section. The first detecting section performs a first adjustment process and makes a detection of a recording medium being transported. The second detecting section is located more downstream than the first detecting section in the transportation direction of the recording medium, performs a second adjustment process which takes a longer time than the first adjustment process, and makes a detection of the recording medium being transported.

Provided is a recording medium detection device which prevents the decline in productivity. The recording medium detection device comprises a first detecting section and a second detecting section. The first detecting section performs a first adjustment process and makes a detection of a recording medium being transported. The second detecting section is located more downstream than the first detecting section in the transportation direction of the recording medium, performs a second adjustment process which takes a longer time than the first adjustment process, and makes a detection of the recording medium being transported.

In a medium conveying device, a projector projects light, a projection light amount of the light changes, at every fixed time, to a first projection light amount and a second projection light amount less than the first projection light amount, a receiver receives the light projected from the projector, a processor determines, at fixed sampling timings, whether a reception light amount of the receiver is at a first reception light level or a second reception light level smaller than the first reception light level, determines, when the reception light amount alternately changes to the first reception light level and the second reception light level, that a medium is not present on a conveying path, and determines, when the reception light amount is fixed to either the first reception light level or the second reception light level, that the medium is present on the conveying path.

In a medium conveying device, a projector projects light, a projection light amount of the light changes, at every fixed time, to a first projection light amount and a second projection light amount less than the first projection light amount, a receiver receives the light projected from the projector, a processor determines, at fixed sampling timings, whether a reception light amount of the receiver is at a first reception light level or a second reception light level smaller than the first reception light level, determines, when the reception light amount alternately changes to the first reception light level and the second reception light level, that a medium is not present on a conveying path, and determines, when the reception light amount is fixed to either the first reception light level or the second reception light level, that the medium is present on the conveying path.

A sheet loading device includes a discharge roller pair, a loading tray, a paddle member, a sheet holding member, a tray lifting-lowering drive portion, a top surface detection sensor, and a control portion. The control portion is capable of performing a lifting-lowering operation to arrange the loading tray at a reference position by lowering the loading tray with the sheet holding member arranged at the holding position to turn the top surface detection sensor into an off state, then lifting the loading tray to turn the top surface detection sensor into an on state, and then lowering the loading tray again to turn the top surface detection sensor into the off state and stopping the loading tray. With the loading tray at the reference position, a predetermined clearance is provided between a top surface of a sheet loaded on the loading tray and a rotational orbit of the paddle member.

A light detection sensor includes a light source that irradiates a detection target with light, a rod lens that collects emitted light from the detection target, a first light receiving element that detects the emitted light that has passed through the rod lens, and a second light receiving element that detects the emitted light that has passed through the rod lens, at a position different from a position at which the first light receiving element detects the light.