An image forming apparatus includes first and second light emitting units, a light receiving unit for receiving light of the first light emitting unit when it is reflected, and receiving light of the second light emitting unit when it is not reflected, to output a signal of a predetermined level, and a control unit for starting light emission of the first light emitting unit before a front end of a paper sheet reaches an area, stopping light emission of the first light emitting unit while starting light emission of the second light emitting unit before a rear end of the paper sheet passes the area, and detecting a length of the paper sheet based on time after the output signal becomes a predetermined level during light emission of the first light emitting unit until the output signal becomes the predetermined level during light emission of the second light emitting unit.

An image forming apparatus includes a stack portion, a regulation portion, a detection unit, and a control unit. The regulation portion regulates a position of an edge of recording material stacked on the stack portion. The detection unit detects the position of the edge of the stacked and regulated recording material, and outputs a detection signal per the recording material edge detected position. Where the position of the recording material edge is detected, the control unit obtains a first width of the recording material stacked on the stack portion, calculates a second width of the recording material based on the detection signal output from the detection unit, and obtains a third width of the recording material by correcting a width of the recording material based on difference information between the second width of the recording material and the first width of the recording material.

A sheet feeding apparatus includes a supporting portion, a feeding portion, a regulation unit, and a sensor. The supporting portion configured to support a sheet. The feeding portion configured to feed the sheet supported by the supporting portion. The regulation unit configured to regulate a position of an edge portion of the sheet supported by the supporting portion. The sensor configured to output an output value that changes in accordance with an amount of movement of the regulation unit in the moving direction. The sensor is disposed above the supporting portion and the regulation portion in a gravity direction, and above an abutment position between the sheet supported by the supporting portion and the feeding portion in the gravity direction.

A cleaning device includes a separation and contact mechanism that separates a web from a conveyance roller and brings the web into contact with the conveyance roller, and a controller. The controller includes a conveyed sheet number determination unit and a separation and contact control unit. The conveyed sheet number determination unit monitors a conveyed sheet number of both-surface image forming sheets where image forming processing is applied to both a first surface and a second surface with respect to the sheets conveyed by the conveyance roller, and determines whether or not a cumulative value of the conveyed sheet number has reached a predetermined threshold value. The separation and contact control unit controls the separation and contact mechanism so as to allow the web to be pressed to the conveyance roller by a pressing roller when the cumulative value of the conveyed sheet number has reached the threshold value.

The fixing device includes a film that is heated by a heater having at least two heat generation members, a pressure roller that forms a fixing nip portion together with the film, a heat generation member switching device that switches a power supply path for supplying power to the at least two heat generation members; and a CPU that controls the heat generation member switching device. In continuous printing on small-size sheets, the CPU causes, while a small-size sheet is held in the fixing nip portion N, the heat generation member switching device to start the operation of switching the power supply path so that power is supplied to one of the at least two heat generation members.

An image forming apparatus may include: a sheet storage that may store a sheet; a first sheet sensor that may determine a sheet size of the sheet stored in the sheet storage; a feeder that may feed the sheet from the sheet storage to a transport path based on the sheet size determined by the first sheet sensor; an image former that may form an image on the sheet fed to the transport path; a second sheet sensor that may (i) be provided downstream of the image former on the transport path, (ii) read the sheet in the transport path, and (iii) settle the sheet size of the sheet; and a hardware processor that may perform adjustment of image formation on the sheet based on the sheet size settled by the second sheet sensor.

A heating device includes a rotator, a fan, an introduction duct, a cooling duct, and a movement mechanism. The rotator has a heater inside thereof. The fan is configured to generate an airflow towards a surface of the rotator. The introduction duct is positioned with respect to the fan and shaped such that the airflow is directed towards and is incident on a first end portion of the rotator in an axial direction of the rotator. The cooling duct extends between the introduction duct and a first end of the rotator in the axial direction, and faces the first end portion of the rotator. The cooling duct includes a plurality of duct portions extending along the rotational axis. The movement mechanism is configured to move the fan, the introduction duct, and at least one of the duct portions of the cooling duct along the rotational axis.

A heating device includes a rotator, a fan, an introduction duct, a cooling duct, and a movement mechanism. The rotator has a heater inside thereof. The fan is configured to generate an airflow towards a surface of the rotator. The introduction duct is positioned with respect to the fan and shaped such that the airflow is directed towards and is incident on a first end portion of the rotator in an axial direction of the rotator. The cooling duct extends between the introduction duct and a first end of the rotator in the axial direction, and faces the first end portion of the rotator. The cooling duct includes a plurality of duct portions extending along the rotational axis. The movement mechanism is configured to move the fan, the introduction duct, and at least one of the duct portions of the cooling duct along the rotational axis.

The fixing device includes a film that is heated by a heater having at least two heat generation members, a pressure roller that forms a fixing nip portion together with the film, a heat generation member switching device that switches a power supply path for supplying power to the at least two heat generation members; and a CPU that controls the heat generation member switching device. In continuous printing on small-size sheets, the CPU causes, while a small-size sheet is held in the fixing nip portion N, the heat generation member switching device to start the operation of switching the power supply path so that power is supplied to one of the at least two heat generation members.

A document transport device includes a placement portion, a slide member, a movable piece, and a detector. A document is to be placed on the placement portion. The slide member includes a document guide that contacts one lateral side of the document which is placed on the placement portion. The movable piece is provided to the slide member, and includes a shading pattern composed of plural patches that have plural densities corresponding to plural document sizes and having plural adjacent patch density differences that are different from each other. The detector detects a density of the shading pattern, and outputs an output signal for document size recognition.