A high voltage power supply apparatus includes: a comparator, a transformer, a rectifier, and a detector. The comparator is to control output of a basic voltage. A high voltage based on the basic voltage is used to perform an image forming job in an image forming apparatus. The transformer is to output an alternating current voltage of a second side of the transformer by amplifying an alternating current voltage of a first side of the transformer, the amplifying being based on a resonance phenomenon induced from the basic voltage. The rectifier is to output the high voltage by rectifying the alternating current voltage of the second side. The detector is to sense a voltage applied to the comparator and a voltage applied to the transformer, and is to output operational state information of the high voltage power supply apparatus based on the sensed voltages.

An image forming unit insertable into an image forming apparatus includes a photosensitive drum and a drum case supporting the photosensitive drum. The drum case includes a guide configured to (i) at least partially engage with a solid head of the image forming apparatus when inserted into the image forming apparatus along a first direction and (ii) guide the solid head in a second direction orthogonal to the first direction when the solid head is selectively repositioned along the second direction toward the photosensitive drum.

In order to properly suppress a discharge defect corresponding to an image ratio of a sheet, in the case where a coefficient of friction is different according to the image ratio of an image on the sheet, an air blowing section is arranged to blow air toward a downstream side in a transport direction from between a downstream-side end portion of a first stacking section and an upstream-side end portion of a second stacking section. When an image ratio of an image on a sheet by an image forming apparatus is a first value, the air blowing section sets an air quantity blown to the sheet at a first air quantity F1, while when the image ratio is a second value higher than the first value, setting the air quantity blown to the sheet at a second air quantity F2 larger than the first air quantity F1.

An image forming unit forms an image based on image data. A roller conveys a sheet from a tray. A reading unit reads the sheet. A controller controls the image forming unit to form a test image on one side of the sheet, controls the roller to convey the sheet on which the test image has been formed, obtains first read data relating to a read result of a first surface of the sheet on which the test image is formed, obtains second read data relating to a read result of a second surface from the first read data and the second read data, selects read data relating to a read result relating to the test image, and controls, based on the selected read data, a density of an output image to be formed by the image forming unit.

According to one embodiment, an image forming apparatus includes: a registration roller; a motor configured to drive the roller; and a controller configured to control the motor. The roller is disposed at a first position on a conveyance path of paper on which an image is to be formed, and sends out the paper toward a second position on the conveyance path. The second position is downstream from the first position on the conveyance path and is an image transfer position on the paper. The controller controls the motor by using both speed control and position control when the leading end of the paper is at a position from the first position to the second position, and controls the motor by using only the speed control when the leading end of the paper reaches the second position.

In an image forming apparatus a toner cartridge includes a toner memory storing toner identification information. The toner cartridge is detachably attachable to a drum cartridge. The drum cartridge includes a drum memory storing drum identification information. The drum cartridge is detachably attached to the main-body casing. A controller performs a request process to request execution of a density correction process to correct a density of developer, in a case where a toner identification information determination process determines that the toner identification information stored in the toner memory does not match the toner identification information which is stored in the main-body memory in a toner identification information storing process or a drum identification information determination process determines that the drum identification information stored in the drum memory does not match the drum identification information which is stored in the main-body memory in the drum identification information storing process.

An image forming apparatus includes a developing roller, a photo-interrupter, and a separation mechanism. The developing roller is movable between a contact position and a separated position. The photo-interrupter includes a light emitting element and a light receiving element. The separation mechanism includes a cam configured to move the developing roller between the contact position and the separated position. The cam includes a phase detection wall extending in a circumference direction. The phase detection wall has a first slit and a second slit. The first slit allows the light emitted from the light emitting element to pass therethrough when the developing roller is at the separated position. The second slit allows the light emitted from the light emitting element to pass therethrough when the developing roller is at the contact position. A size of the first slit in the circumferential direction is different from that of the second slit.

An image forming apparatus includes a processor. The processor is configured to emit a laser beam reflected by a polygon mirror, the polygon mirror rotated by a polygon motor, form an image based on a latent image carried on a photoconductor by the laser beam, store an execution frequency of an image quality self-check of the image formed and a rotation duration of the polygon motor during a standby operation period of image formation, accept a change in the execution frequency, change the rotation duration based on the change in the execution frequency, execute the image quality self-check based on the execution frequency, and continuously rotate the polygon motor during the standby operation period based on the rotation duration stored.

Copy and scan printing may include scanning, by scanner disposed along a paper path between a paper delivery roller and a paper pickup roller, content of documents (302). Further, copy and scan printing may include determining whether the documents are to be copied (304), in response to a determination that the documents are to be copied, determining whether a page count of the documents to be copied is available (306), and generating copies of the documents (310).

An image forming apparatus includes a fixing device including a heating roller configured to heat a sheet when the heating roller rotates, a temperature sensor configured to detect a temperature of the heating roller; and a controller configured to obtain a temperature detected by the temperature sensor at intervals of a predetermined sampling time, calculate, at the intervals of the predetermined sampling time, a temperature-decrease-amount of the detected temperature over a unit time that is longer than the predetermined sampling time, and stop rotation of the heating roller when the calculated temperature-decrease-amount is greater than a predetermined threshold value.