An image forming apparatus includes an image forming unit, a fixing unit, and a control unit. The image forming unit forms a toner image on a recording material. The fixing unit heats and fix the toner image formed on the recording material to the recording material in a fixing nip portion. The fixing unit includes a heater and a nip portion forming member that forms the fixing nip portion to pinch and convey the recording material. The control unit control the power to be supplied to the heater so as to change a temperature gradient at time of warm-up of the fixing unit to a target temperature in accordance with time from start of power supply to the heater until entry of the recording material into the fixing nip portion.

In an image forming system including an apparatus main-body and a control portion which controls a fixing operation, to the apparatus main-body, a first fixing unit including a first heater and a second fixing unit including a second heater, which is different from the first heater, can be selectively attached, and each of the first and second fixing units has an information processing portion which transmits data including identification information and temperature information related to a temperature detected by a temperature detection element to the control portion, and the control portion discriminates which of the first fixing unit and the second fixing unit, the fixing unit attached to the apparatus main-body is on the basis of the identification information from the information processing portion and controls the fixing operation by the fixing unit on the basis of the temperature information.

An image forming apparatus includes a rotatable image bearing member, a transfer member, a cleaning blade, a driving portion, and a controller. The controller is capable of executing, at a time of an end of a job, a plurality of operations including a first reverse rotating operation, a first normal rotating operation executed subsequently to the first reverse rotating operation, a second reverse rotating operation executed after the first normal rotating operation, and a second normal rotating operation executed subsequently to the second reverse rotating operation. The controller controls the driving portion so that a movement amount of the image bearing member in the second normal rotating operation is smaller than a movement amount of the image bearing member in the second reverse rotating operation.

A power control device includes a heater, a zero-cross detecting unit, a triac, a supplying unit, and a controlling unit. The supplying unit discharges an electric charge when a control signal is outputted in a half-wave of each of a first polarity and a second polarity and charges the electric charge when the control signal is not outputted in the half-wave of the first polarity. The controlling unit outputs: in a first half-wave, a first control signal on the basis of the zero-cross point and a second control signal in a first phase different in timing from the first control signal, and in a second half-wave, a third control signal on the basis of the zero-cross point and a fourth control signal in a second phase different in timing from the second control signal. The first phase and the second phase are different from each other.

An image forming device comprises a media container accommodating a sheet-type medium, an image forming engine, a media conveyor configured to convey the sheet-type medium along a conveyance path from the media container to the image forming engine. The media conveyor has a plurality of conveying rollers including a first conveying roller arranged on an upstream side of the image forming engine and a second conveying roller arranged on a downstream side of the image forming engine. The image forming device further comprises a cutter arranged on an upstream side along the conveyance path with respect to the second conveying roller, and a controller. The controller is configured to control the media conveyor in such a manner that the cut sheet-type medium is conveyed and discharged toward outside after a power is on and before first execution of the image forming process.

An apparatus includes an image forming portion 10 for forming an image on a sheet; a first rotatable member 100; a second rotatable member 101 cooperative with the first rotatable member to form a nip for fixing the image formed by the image forming portion, on the sheet; a pressing mechanism 112, 113 for pressing the first rotatable member toward the second rotatable member; a moving mechanism 120 for moving the pressing mechanism between a first position in which the nip is formed by the first rotatable member and the second rotatable member, and a second position in which the first rotatable member and the second rotatable member are spaced from each other; and a controller 800 for controlling an operation of the moving mechanism, wherein the image forming apparatus is capable of executing an operation in a control mode in which a pressure releasing operation is executed such that the pressing mechanism is shifted from the first position to the second position after elapse of a predetermined time after completion of execution of the image formation job. The apparatus includes a manual operating portion 831 in which selection and setting can be executed as to whether to execute the operation in the control mode.

Devices include electrically conductive elements contacting a vacuum belt, and a voltage source connected to the electrically conductive elements. The electrically conductive elements form an electrical circuit from the voltage source, through the belt, and back to the voltage source. The electrically conductive elements are positioned so that they are separated from the belt when the belt moves the sheets of media between the electrically conductive elements and the belt. A processor is capable of identifying leading edges of the sheets of media on the belt (when voltage of the electrical circuit changes from a relatively higher voltage to a relatively lower voltage) and identifying trailing edges of the sheets of media on the belt (when the voltage of the electrical circuit changes from the relatively lower voltage back to the relatively higher voltage).

A developing cartridge includes: a developing roller; a coupling for rotating the developing roller; a shaft; and a clutch. The developing roller is rotatable about a first axis extending in an axial direction. The coupling is rotatable about a second axis extending in the axial direction. The shaft rotatably supports the coupling. The clutch is rotatable together with the coupling about the shaft in a case where the coupling rotates in a first rotational direction. In a case where the coupling rotates in a second rotational direction opposite to the first rotational direction, the clutch engages with a portion of the shaft and the clutch and the coupling do not rotate.

An image forming apparatus includes an image forming unit, a retransport assembly, and a controller. The retransport assembly includes a first transport roller pair, a second transport roller pair, and a skew roller pair configured to alone transport, in a skewed manner, a sheet spaced from the first transport roller pair and the second transport roller pair, and a reference wall. The controller controls the retransport assembly and executes a waiting operation to cause the sheet to wait at the retransport assembly. The controller is configured to execute the waiting operation by stopping the skew roller pair and one of the first transport roller pair and the second transport roller pair in a state in which the sheet is nipped by the skew roller pair and the one of the first transport roller pair and the second transport roller pair.

An image forming apparatus includes an image bearing member, a developing member, a controller configured to carry out switching control between a first state in which the developing member is caused to act on the image bearing member and a second state in which the developing member is not caused to act on the image bearing member, a transfer member, and a detector configured to read density information of the recording material. The controller detects a fog density on the basis of a difference in density information between a fog non-occurrence region of a non-image region of the recording material in the second state and a fog occurable region of the non-image region of the recording material in the first state.