In an image forming apparatus, an image forming unit configured to form a toner image on a transfer medium includes four sets of a photoconductor drum and a development roller, respectively, for forming toner images of first, second, third and fourth colors, arranged in this order, in a direction opposite to a direction of movement of the transfer medium moving toward a detector configured to detect a toner image formed on the transfer medium. A controller executes a bias-corrective test image forming process in which a first bias-corrective test image of the first color is arranged in a position downstream of other three first bias-corrective test images, and a second bias-corrective test image of the first color is arranged in a position between two first bias-corrective test images selected among other three first bias-corrective test images, in the direction of movement of the transfer medium.

According to an embodiment, an image forming apparatus performs first image density adjustment by measuring image density of a first test pattern formed using a rotation member. The image forming apparatus forms, where a first variation that is a variation of a predetermined number of image density detection values or adjustment values by the first image density adjustment is a predetermined threshold value or more, a second test pattern on a transfer body using the rotation member, the second test pattern being longer than a peripheral length of the rotation member in a sub-scanning direction.

A fixing device includes a fixing roller and a pressure roller provided in a rotatable manner, a heat source for heating the fixing roller, and a controller for controlling AC power supplied to the heat source. The fixing device fixes an unfixed image on a sheet held and conveyed by the fixing roller and the pressure roller. The controller causes a current to flow including current-carrying waveforms having different phase angles in half-wave units during preset control cycles.

A power source apparatus including a control unit configured to output a control signal to a switching element to switch a target voltage of an output voltage from a transformer. In a case of increasing the output voltage, the control unit outputs the control signal having a first duty when the target voltage is lower than a first threshold value, and outputs the control signal having a second duty larger than the first duty when the target voltage is switched to a value equal to or higher than the first threshold value. In a case of reducing the output voltage, the control unit outputs the control signal having the second duty when the target voltage is equal to or higher than a second threshold value, and outputs the control signal having the first duty when the target voltage is switched to a value lower than the second threshold value.

An amount-of-remaining-toner detecting device includes: a toner housing portion in which a toner bottle is housed, the toner bottle having a bottle body that is cylindrical and in which toner is housed, and a cap that is attached to one end of the bottle body in an axial direction of the bottle body and from which the toner housed in the bottle body is discharged; and circuitry configured to detect an amount of remaining toner in the toner bottle housed in the toner housing portion. The toner housing portion includes a first pair of electrodes facing each other with the bottle body interposed between the first pair of electrodes, and a second pair of electrodes facing each other with the bottle body interposed between the second pair of electrodes, at respective positions closer to the cap than the first pair of electrodes are. The circuitry detects the amount of remaining toner in the bottle body, based on at least one of a capacitance value between the first pair of electrodes or a capacitance value between the second pair of electrodes.

In an image forming apparatus, a tray having first and second receiving portions is configured to move between a first position, at which at least part of the tray is positioned inside an apparatus body, and a second position, at which the tray is outside the apparatus body. The tray in the first position allows a first recording medium to be conveyed from the first receiving portion. When the tray is in the first position, the second receiving portion is configured to move between a third position, which is at an upstream side relative to a first opening of the apparatus body in a second direction, and a fourth position, which is at a downstream side relative to the third position in the second direction. The second receiving portion at the third position allows a second recording medium to be conveyed from the second receiving portion in the second direction.

A printing apparatus capable of conveying sheets to a sheet processing apparatus and to control the type of a sheet to be used as a cover sheet in a case where a book bound product is generated by switching back sheets each having an image printed, inverting the sheets and folding the inverted sheets, and to notify an error to a user based on the type of a sheet to be used as the cover sheet in a case where printing an image on the cover sheet is designated.

Apparatus and methods are provided for measuring the dryness of primer on a substrate in an inline priming system. In implementations, the apparatus comprises a plurality of measurement electrodes spaced laterally to extend across and contact a primed surface of a substrate following application of a primer to the substrate as it is fed through the inline priming system. A resistance measurement unit is provided as part of the dryness measuring apparatus to, in use, measure the surface resistance of the primed substrate between different measurement electrodes across the primed surface of a substrate. A controller is provided in the dryness measurement apparatus, the controller arranged to, in use: receive the measured surface resistance value and to generate, based on the measured surface resistance values, a dryness profile indicative of the dryness of the primer at locations across the substrate in the direction of the spacing of the electrodes.

An image forming apparatus includes an engine to form an image on an image forming medium, a paper transfer device to pick up a printing paper and transfer the paper to a transfer path, a sensor to sense a printing paper at a predetermined position on the transfer path, and a processor to determine whether a transfer delay occurs, when the printing paper is sensed, and adjust a pickup timing to advance a pickup of a printing paper of a next page.

A movement member that causes a cleaning member to move so as to reciprocally move on a transparent member is provided. A cleaning process is performed in accordance with an instruction on a number of times of movement of the movement member.