A process cartridge detachably mountable to an electrophotographic image forming apparatus including a main assembly side drive transmission member and a main assembly side urging member, the cartridge including a rotatable photosensitive drum; a rotatable developing roller for developing a latent image formed on the drum, the developing roller contactable to and spaceable from the drum; an urging force receiving portion for receiving an urging force from the urging member to space the roller from the drum; a cartridge side drive transmission portion capable of coupling with the main assembly side drive transmission member to receive a rotational force for rotating the roller; a releasing member capable of urging the main assembly side drive transmission member to decouple the cartridge side drive transmission member from the main assembly side drive transmission member by the urging force receiving portion receiving the urging force from the main assembly side urging member.

A toner coverage sensing system is provided for sensing toner particles printed onto a surface of a process element using an electrophotographic printing system. The printed toner particles include porous color toner particles. An infrared radiation source directs infrared radiation onto the printed toner particles on the surface of the process element A diffused radiation detector senses infrared radiation scattered from the printed toner particles, wherein the diffused radiation detector is oriented such that that the sensed infrared radiation does not include specular reflections from the surface of the process element. A data processing system determines a sensed toner coverage for the porous color toner particles on the surface of the process element responsive to the sensed scattered infrared radiation.

A toner coverage sensing system is provided for sensing toner particles printed onto a surface of a process element using an electrophotographic printing system. The printed toner particles include porous color toner particles. An infrared radiation source directs infrared radiation onto the printed toner particles on the surface of the process element A diffused radiation detector senses infrared radiation scattered from the printed toner particles, wherein the diffused radiation detector is oriented such that that the sensed infrared radiation does not include specular reflections from the surface of the process element. A data processing system determines a sensed toner coverage for the porous color toner particles on the surface of the process element responsive to the sensed scattered infrared radiation.

A light-emitting component includes a light-emitting element, a thyristor, and a light-absorbing layer. The thyristor includes a semiconductor layer having a bandgap energy smaller than or equal to a bandgap energy equivalent to a wavelength of light emitted by the light-emitting element. The thyristor causes the light-emitting element to emit light or causes an amount of light emitted by the light-emitting element to increase, upon entering an on-state. The light-absorbing layer is disposed between the light-emitting element and the thyristor such that the light-emitting element and the thyristor are stacked. The light-absorbing layer absorbs the light emitted by the light-emitting element.

A light-emitting component includes a light-emitting element, a thyristor, and a light-absorbing layer. The thyristor includes a semiconductor layer having a bandgap energy smaller than or equal to a bandgap energy equivalent to a wavelength of light emitted by the light-emitting element. The thyristor causes the light-emitting element to emit light or causes an amount of light emitted by the light-emitting element to increase, upon entering an on-state. The light-absorbing layer is disposed between the light-emitting element and the thyristor such that the light-emitting element and the thyristor are stacked. The light-absorbing layer absorbs the light emitted by the light-emitting element.

A toner case includes a toner storage portion, a cylindrical portion, a shutter member, and a biasing member. The cylindrical portion has an interior space and communicated with the interior of the toner storage portion through a toner discharge port. An opening is formed at one of opposite ends of the interior space, and a closing wall is formed at the other of the opposite ends of the interior space. The shutter member is supported so as to be slidable in an extension direction of the cylindrical portion, and is movable between a closing position and an opening position. The shutter member at the closing position closes the toner discharge port, and the shutter member at the opening position opens the toner discharge port. The biasing member configured to position the shutter member to the closing position by applying a biasing force to the shutter member.

A toner case includes a toner storage portion, a cylindrical portion, a shutter member, and a biasing member. The cylindrical portion has an interior space and communicated with the interior of the toner storage portion through a toner discharge port. An opening is formed at one of opposite ends of the interior space, and a closing wall is formed at the other of the opposite ends of the interior space. The shutter member is supported so as to be slidable in an extension direction of the cylindrical portion, and is movable between a closing position and an opening position. The shutter member at the closing position closes the toner discharge port, and the shutter member at the opening position opens the toner discharge port. The biasing member configured to position the shutter member to the closing position by applying a biasing force to the shutter member.

An image forming apparatus including a controller, which starts rotation of a rotary polygon mirror when a predetermined condition is satisfied, rotates the rotary polygon mirror at a predetermined rotation speed based on a first pulse in a first state in which light beams are not emitted from a light source, thereafter starts emission of the light beams, switches a rotation control based on the first pulse to a rotation control based on the second pulse, and rotates the rotary polygon mirror at the predetermined rotation speed based on the second pulse in a second state in which the light beams are emitted from the light source, and thereafter detects a temperature of a drive circuit board by a temperature detector, and corrects color misregistration using a detected temperature of the temperature detector and the detection result of a pattern detector.

In accordance with an embodiment, an image forming apparatus encompasses a heat roller, a lamp, a use amount acquisition section, a switching controller and a cycle controller. The heat roller heats a sheet printed with a toner image. The lamp heats the heat roller. The use amount acquisition section acquires a use amount of the lamp. The switching controller repeats a processing from a moment at which the lamp is charged until the lamp is charged next after the lamp is not charged in a predetermined control cycle. The cycle controller sets the cycle based on the use amount.

In accordance with an embodiment, an image forming apparatus encompasses a heat roller, a lamp, a use amount acquisition section, a switching controller and a cycle controller. The heat roller heats a sheet printed with a toner image. The lamp heats the heat roller. The use amount acquisition section acquires a use amount of the lamp. The switching controller repeats a processing from a moment at which the lamp is charged until the lamp is charged next after the lamp is not charged in a predetermined control cycle. The cycle controller sets the cycle based on the use amount.