An image forming apparatus includes an image forming portion configured to form a toner image. The image forming portion includes: a photosensitive body; a charging device; an exposure device; a toner supply device; and a transfer device. A continuously printed amount, which has been attained by the image forming portion while the image forming portion has formed toner images continuously with a time interval between every two successive image-forming timings having a length shorter than or equal to a prescribed length, is determined. A charging voltage to be applied to the charging device is set based on a sum of a reference charging voltage and a correction value, the reference charging voltage being determined based on a target surface potential of the photosensitive body, the correction value being determined based on the continuously printed amount.

According to an embodiment, there is provided an image forming apparatus that forms a color image using a plurality of discolorable coloring materials and a plurality of non-discolorable coloring materials. In a case where insufficiency of at least one coloring material from among the plurality of discolorable coloring materials and the plurality of non-discolorable coloring materials is detected, the image forming apparatus performs color image formation using the plurality of discolorable coloring materials and the plurality of non-discolorable coloring material in combination.

A nip member is disposed inside the endless belt and elongated in a longitudinal direction. A backup member sandwiches the endless belt against the nip member to form a nip portion at which the backup member and the endless belt are in contact with each other and configured to convey a recording sheet in a conveying direction perpendicular to the longitudinal direction. A downstream end of the nip portion in the conveying direction is arced with a longitudinal center portion thereof further upstream than longitudinal end portions thereof. The nip member includes a first portion sandwiching the endless belt against the backup member, and a second portion positioned downstream of the first portion in the conveying direction and bent in a direction away from the backup member. The second portion is arced with a longitudinal center portion thereof further upstream in the conveying direction than longitudinal end portions thereof.

An image forming apparatus includes a body casing, a drum unit movable between an inside position and an outside position, and a waste toner storage unit. The drum unit includes a photosensitive drum, a cleaning unit configured to remove toner remaining on a surface of the photosensitive drum, a conveying unit including a conveying member to convey the toner in a moving direction of the drum unit, and a conveying tube that can accommodate the conveying member and having a discharging outlet through which the toner is discharged to the waste toner storage unit. Moreover, the conveying tube includes a first conveying tube extending in the moving direction and accommodating the conveying member, and a second conveying tube connectable to the first conveying tube and extending in a direction intersecting with a direction in which the first conveying tube extends.

An exposure unit includes a light-emitting element array and a lens array. The light-emitting element array includes a plurality of light-emitting elements that are disposed in a first direction and each emit a light beam. The lens array faces the light-emitting element array in a second direction that is orthogonal to the first direction, and focuses the light beams emitted from the respective light-emitting elements. The following expression [3] is satisfied. A symmetric property, determined from the following expression [1], of a light amount distribution in the first direction of at least one of the light beams focused by the lens array satisfies the following expression [2].

S=|(HLHR)/(XE/2)|[1]

0S0.65[2]

LoLB[3]

An image forming apparatus includes a photosensitive member, a charger, a developing device, a transfer device, a scraper, and a controller. The controller performs an image formation process to form the developer image on the photosensitive member by using the developing device. The controller acquires, as a first value, at least one of a value of the charging current flowing in the charger and a value of the transferring current flowing in the transfer device. The controller calculates an accumulation current value by using result of an integral of a second value over time. The second value is an absolute value of the first value. The controller performs a scraping process in which the scraper scrapes the photosensitive member when the accumulation current value reaches a threshold value.

A fixing device for thermally fixing a toner image on a sheet includes a heat unit, a pressure unit, and a nip member. One of the heat unit and the pressure unit includes an endless belt having a width in a widthwise direction and a restriction member configured to be abutted against the endless belt. The endless belt includes a base layer having an outer peripheral surface and a pair of widthwise end faces in the widthwise direction, the base layer defining an inner space, and an elastic layer formed on the outer peripheral surface and having a thickness and a pair of widthwise end surfaces in the widthwise direction. One of the end faces and a corresponding one of the end surfaces provides a maximum distance therebetween in the widthwise direction smaller than the thickness of the elastic layer.

According to an embodiment, there is provided an image forming apparatus that forms a color image using a plurality of discolorable coloring materials and a plurality of non-discolorable coloring materials. In a case where insufficiency of at least one coloring material from among the plurality of discolorable coloring materials and the plurality of non-discolorable coloring materials is detected, the image forming apparatus performs color image formation using the plurality of discolorable coloring materials and the plurality of non-discolorable coloring material in combination.

A method is described for adjusting the focus position of a linear printhead in a digital printing system. A line image is printed including a plurality of variable linewidth lines at different cross-track positions. A digital image capture system is used to capture an image of the printed line image, and a data processing system is used to automatically analyze the captured image to determine linewidth parameters representing linewidths of the plurality of lines. Linewidth progression functions are determined for the lines responsive to the determined linewidths, wherein the linewidth progression functions represent the linewidth parameters as a function of position. The linewidth progression functions are analyzed to determine defocus characteristics of the linear printhead, which are used to adjust the focus position of the linear printhead.

An image forming apparatus, comprising: a body casing, a drum unit movable between an inside position and an outside position, and a waste toner storage unit, and wherein the drum unit comprises a photosensitive drum, a cleaning unit to remove toner remaining on a surface of the photosensitive drum, and a conveying unit including a conveying member to convey the toner in a moving direction of the drum unit, and a conveying tube to accommodate the conveying member and to have a discharging outlet through which the toner is discharged to the waste toner storage unit, and wherein the conveying tube comprises: a first conveying tube to extend in the moving direction and to accommodate the conveying member, and a second conveying tube to be connected to the first conveying tube and to extend in a direction intersecting with a direction in which the first conveying tube extends.