In order to prevent interference between a primary transfer bias voltage and a secondary transfer bias voltage, and to prevent occurrence of an image defect due to interference between these bias voltages, an image forming apparatus includes a plurality of primary transfer rollers, an intermediate transfer belt, a drive roller, a secondary transfer roller, and a rectifier roller. A primary transfer bias voltage of a polarity opposite to the polarity of toner is applied to a primary transfer bias applying unit. A secondary transfer bias voltage of a same polarity as the polarity of toner is applied to the drive roller. The rectifier roller is disposed between a most-downstream primary transfer roller and the drive roller. A bias voltage of the same polarity as the polarity of the primary transfer bias voltage or the polarity of the secondary transfer bias voltage is applied to the rectifier roller.

In order to prevent interference between a primary transfer bias voltage and a secondary transfer bias voltage, and to prevent occurrence of an image defect due to interference between these bias voltages, an image forming apparatus includes a plurality of primary transfer rollers, an intermediate transfer belt, a drive roller, a secondary transfer roller, and a rectifier roller. A primary transfer bias voltage of a polarity opposite to the polarity of toner is applied to a primary transfer bias applying unit. A secondary transfer bias voltage of a same polarity as the polarity of toner is applied to the drive roller. The rectifier roller is disposed between a most-downstream primary transfer roller and the drive roller. A bias voltage of the same polarity as the polarity of the primary transfer bias voltage or the polarity of the secondary transfer bias voltage is applied to the rectifier roller.

A cleaning device includes a removal roller, a collecting roller, a blade, and a toner storage section. The removal roller and the collecting roller do not have relationship such that a rotation speed or a diameter of one of the removal roller and the collecting roller is an integral multiple of a rotation speed or a diameter of the other removal roller and collecting roller. A first outer circumferential region having a first surface roughness and extending in an axial direction of a second rotary shaft and a second outer circumferential region having a greater second surface roughness than the first surface roughness and extending in the axial direction of the second rotary shaft are provided on an outer circumferential surface of the collecting roller in a circumferential direction thereof. A width of the second outer circumferential region is smaller than a width of the first outer circumferential region.

An optical writing device driving a light-emitting element array, modulating light according to a screening pattern that expresses a dithered image, and performing optical writing by focusing light emitted from the light-emitting element array through a lens array onto a photoreceptor. The optical writing device includes an acquisition unit that acquires a write start position for writing to the photoreceptor in a main scanning direction and a control unit that performs a control when the write start position corresponds to an i-th light-emitting element from a reference position that corresponds to a first light-emitting element in the main scanning direction, i being a positive integer greater than 1, wherein the control unit supplies pixel values to the i-th light-emitting element onwards, the pixel values being assigned from pixels of the screening pattern from an i-th pixel onwards, from a leading pixel of the screening pattern in the main scanning direction.

An optical writing device driving a light-emitting element array, modulating light according to a screening pattern that expresses a dithered image, and performing optical writing by focusing light emitted from the light-emitting element array through a lens array onto a photoreceptor. The optical writing device includes an acquisition unit that acquires a write start position for writing to the photoreceptor in a main scanning direction and a control unit that performs a control when the write start position corresponds to an i-th light-emitting element from a reference position that corresponds to a first light-emitting element in the main scanning direction, i being a positive integer greater than 1, wherein the control unit supplies pixel values to the i-th light-emitting element onwards, the pixel values being assigned from pixels of the screening pattern from an i-th pixel onwards, from a leading pixel of the screening pattern in the main scanning direction.

An image forming device according to an embodiment includes a photosensitive drum and a light-emitting unit with a plurality of light-emitting elements which form an electrostatic latent image on the photosensitive drum. A processor controls a storage unit to store a cumulative light emission time of each light-emitting element. The processor further controls the storage unit to store an adjustment time which is shorter than a longest cumulative light emission time of the light-emitting elements. When a predetermined condition is satisfied, the processor controls at least one of the light-emitting elements that has a cumulative light emission time which is shorter than the adjustment time to emit light until the cumulative light emission time thereof equals the adjustment time.

An image forming apparatus includes an image forming device, a gradation adjustment mark adder and a hardware processor. The hardware processor monitors and adjusts a gradation characteristic based on a result of scanning a gradation adjustment mark. The hardware processor makes a determination as to whether to form the gradation adjustment mark overlapping an image area of an image based on image data. If it is determined to form the gradation adjustment mark overlapping the image area, the hardware processor controls the gradation adjustment mark adder to add gradation adjustment mark information to the image data in the image area.

An image formation apparatus includes an image bearing member on which an electrostatic latent image is formed and a developing agent bearing member configured to carry a developer used to develop the electrostatic latent image formed on the image bearing member. The image formation apparatus forms an image by using the electrostatic latent image formed on the image bearing member. The image formation apparatus further includes an obtaining unit configured to obtain the information about a rotation speed of the image bearing member and a rotation speed of the developing agent bearing member; a determination unit configured to determine, according to the obtained information, a color conversion table used to transfer and record the input image data; and an image formation unit configured to convert a signal of the input image data according to the determined color conversion table and form an image with the converted signal value.

An image formation apparatus includes an image bearing member on which an electrostatic latent image is formed and a developing agent bearing member configured to carry a developer used to develop the electrostatic latent image formed on the image bearing member. The image formation apparatus forms an image by using the electrostatic latent image formed on the image bearing member. The image formation apparatus further includes an obtaining unit configured to obtain the information about a rotation speed of the image bearing member and a rotation speed of the developing agent bearing member; a determination unit configured to determine, according to the obtained information, a color conversion table used to transfer and record the input image data; and an image formation unit configured to convert a signal of the input image data according to the determined color conversion table and form an image with the converted signal value.

An optical scanning device according to an embodiment includes a light source, a MEMS mirror, a MEMS-mirror driving unit, a control unit, and a sensor. The light source radiates a plurality of laser beams that scan a photoconductive drum. The MEMS mirror includes a reflection surface that reflects the plurality of laser beams radiated from the light source. The MEMS-mirror driving unit reciprocatingly moves the MEMS mirror. The sensor supplies a horizontal synchronization signal to the control unit by detecting the laser beam reflected on the reflection surface when the MEMS mirror reaches a predetermined position. After detecting the horizontal synchronization signal supplied from the sensor, the control unit performs the auto power control of the light amount of at least one laser beam among the plurality of laser beams.