A cartridge includes a photosensitive drum and a casing rotatably supporting the photosensitive drum. A coupling is operatively connected to the photosensitive drum so as to be capable of transmitting a driving force toward the photosensitive drum. The coupling includes a main body, a movable portion movable relative to the main body of the coupling between a first position and a second position, and a projection configured to move in a circumferential direction of the coupling relative to the main body of the coupling in response to movement of the movable portion from the first position to the second position.

Provided is an electrophotographic photosensitive member having a feature in that, in a graph that is obtained by a method of measuring an EV curve, and that has a horizontal axis representing I and a vertical axis representing V, when V at I=0.500 [μJ/cm.sup.2] is represented by V.sub.r [V], a maximum value of S [V.Math.μJ/cm.sup.2] represented by S=I.Math.(V−V.sub.r) in a range of I=0.000 to 0.030 [μJ/cm.sup.2] is represented by S.sub.max [V.Math.μJ/cm.sup.2], and a product of a light amount I.sub.i [μJ/cm.sup.2] on the horizontal axis and a potential V.sub.i[V] on the vertical axis at a point of intersection between an approximate straight line in a range of I=0.000 to 0.010 [μJ/cm.sup.2] and an approximate straight line in a range of I=0.490 to 0.500 [μJ/cm.sup.2] is represented by S.sub.i=I.sub.i.Math.(V.sub.i−V.sub.r) [V.Math.μJ/cm.sup.2], a ratio of S.sub.i to S.sub.max, which is represented by AR=S.sub.i/S.sub.max, satisfies AR≤0.10.

In response to detecting that a remaining supply of print material of a first cartridge has reached a first threshold, a printing device transmits a request. In response to detecting that a second cartridge has replaced the first cartridge, the printing device determines whether the remaining supply had reached a second threshold and whether a token permitting usage of the second cartridge was received responsive to the request. In response to determining that the remaining supply had reached the second threshold and that the token was received, the printing device prints with print material from the second cartridge.

An image forming apparatus includes a communication portion arranged inside a cover covering an image forming portion in the main body of the apparatus and including an antenna surface for use in establishing near field communication. The cover includes a stacking portion in its upper section. The stacking portion is configured to receive a recording medium with an image thereon, the recording medium being discharged outside the main body of the apparatus. The antenna surface faces a region of the upper section of the cover downstream in a direction of discharging the recording medium. The antenna surface at least partially faces a region of the upper section of the cover outside the stacking portion in a direction perpendicular to the direction of discharging the recording medium. The communication portion is capable of communicating with another communication portion using near field communication.

An image forming system includes an image forming unit for forming an image on a recording medium, a varnish applying unit for applying varnish to the image on the recording medium, and a control unit for controlling the image forming unit to form a first image and a second image and for controlling the varnish applying unit to apply varnish to the first image and the second image such that a first varnish application amount of the first image applied by the varnish applying unit is different from a second varnish application amount of the second image applied by the varnish applying unit.

An image forming apparatus includes an image forming unit and a power device. The power device includes a circuit board provided to intersect a horizontal plane. The power device includes an electrolytic capacitor, an electric element, and a plate-shaped member that is provided between the electrolytic capacitor and the electric element in a vertical direction and including a first surface extending in a second direction intersecting the vertical direction. The plate-shaped member includes a cutout or a hole, and a position of at least part of an area where the cutout or the hole is formed is farther in the first direction from the mounting surface of the circuit board than a position of the electric element.

A print system includes a head, a conveyance motor, a first connector, and a second connector, a power supply circuit. When a first power source is connected to the first connector and a second power source is connected to the second connector, the power supply circuit supplies at least some of a first power to the head and supplies at least some of a second power to the conveyance motor. The first power is a power of the first power source. The second power is a power of the second power source.

A feeder includes a conveyance path, a conveyance roller that conveys a sheet along the conveyance path, a transmitter that emits a space propagating energy, a receiver that receives a reflected energy obtained by reflection of the space propagating energy, and an actuator mounted pivotably on a pivot shaft and including first and second legs extending in different directions from the pivot shaft. The first leg is disposed to extend to the conveyance path and abut against the sheet being conveyed along the conveyance path. The second leg has a reflective surface crossing a path of the space propagating energy. The actuator is pivoted by abutment of the sheet against the first leg. The reflective surface is formed so that the reflected energy obtained by the reflection of the space propagating energy on the reflective surface enters the receiver regardless of an angle of pivotal movement of the actuator.

An image forming apparatus includes an image bearing member, an image forming portion, a transfer member, an applying portion, and an executing portion configured to execute an output operation for forming and outputting a chart formed on a recording material on which a plurality of test images are transferred by applying a plurality of voltages to the transfer member by the applying portion. The executing portion changes a change width per level of the test voltage so that the change width is a first change width in a case that a material of the recording material on which the chart is formed is a first material and so that the change width is a second change width different from the first change width in a case that the material of the recording material is a second material different from the first material.

An image forming apparatus includes a stacker, a feeding roller, an image forming unit, a detector detecting a recording material, and a controller controlling a feed interval between recording materials continuously fed by the feeding roller. The controller sets the feed interval between a first recording material precedently fed and a second recording material subsequent to the first recording material to a first feed interval based on an image signal. In a case that the detector does not detect a trailing end of the first recording material with respect to a feeding direction after detecting the first recording material until a predetermined time elapses, the controller sets the feed interval to a second feed interval longer than the first interval and determines a timing of image forming on the second recording material by the image forming unit based on the second feed interval.