Abstract: An exposure head includes a first light emitting board group, a first lens array, a second light emitting board group, and a second lens array. The first light emitting board group is disposing a plurality of first light emitting boards each including a plurality of first light emitting elements disposed side by side in a second direction intersecting with the first direction. The plurality of first light emitting boards are disposed along the second direction and alternately in the first direction. The first lens array condenses light emitted from the plurality of first light emitting elements disposed on the first light emitting board group onto the surface of the image bearing member. The second light emitting board group is disposed in a manner separated with respect to the first light emitting board group in the first direction.

Abstract: An image forming apparatus including a photosensitive member, an optical scanning device including a transmission member configured to cause laser light for scanning the photosensitive member to pass through the transmission member, and a developing device configured to develop an electrostatic latent image with toner, the electrostatic latent image being scanned by the laser light and formed on the photosensitive member; a cleaning mechanism configured to clean the transmission member; a counter configured to store a count value that is a number of sheets on which an image forming operation is performed, and a control unit which executes a cleaning sequence before execution of an adjustment sequence, and resets the count value upon execution of the cleaning sequence, in a case where the count value is less than or equal to a predetermined value.

Abstract: An image forming apparatus with an image forming unit, including a photosensitive drum and an optical scanning device having a transparent window through which laser light that scans the photosensitive drum passes. The image forming apparatus further includes a cleaning mechanism configured to clean the transparent window and a controller unit configured to control the cleaning mechanism to clean the transparent window, wherein the controller unit controls the image forming unit to form an adjustment pattern on the photosensitive drum after the cleaning mechanism performs a cleaning operation for cleaning the transparent window.

Abstract: An image forming apparatus including a photosensitive member, an optical scanning device including a transmission member configured to cause laser light for scanning the photosensitive member to pass through the transmission member, and a developing device configured to develop an electrostatic latent image with toner, the electrostatic latent image being scanned by the laser light and formed on the photosensitive member; a cleaning mechanism configured to clean the transmission member; a counter configured to store a count value that is a number of sheets on which an image forming operation is performed, and a control unit which executes a cleaning sequence before execution of an adjustment sequence, and resets the count value upon execution of the cleaning sequence, in a case where the count value is less than or equal to a predetermined value.

Abstract: An image forming apparatus with an image forming unit, including a photosensitive drum and an optical scanning device having a transparent window through which laser light that scans the photosensitive drum passes. The image forming apparatus further includes a cleaning mechanism configured to clean the transparent window and a controller unit configured to control the cleaning mechanism to clean the transparent window, wherein the controller unit controls the image forming unit to form an adjustment pattern on the photosensitive drum after the cleaning mechanism performs a cleaning operation for cleaning the transparent window.

Abstract: An image forming apparatus comprises a semiconductor laser for emitting laser light for irradiating a photosensitive drum, BD for detecting laser light before irradiating the photosensitive drum to output BD signal as a reference for determining an initiation position of the photosensitive drum, and a laser circuit board. The laser circuit board causes the semiconductor laser to emit laser light detected by the BD with first light amount. When a BD sensor outputs the BD signal, a laser circuit board causes the semiconductor laser to emit the laser light with second light amount.

Abstract: An image forming apparatus including: a drive motor configured to rotate a rotary polygon mirror to deflect light beam; a signal generation unit configured to generate a rotation synchronous signal; and a rotation control unit configured to control a rotation speed of the rotary polygon mirror, wherein the rotation control unit executes a masking processing of masking control of the drive motor based on the rotation synchronous signal, wherein a time period of a first masking processing for a first rotation speed is shorter than a time period of a second masking processing for the second rotation speed, and wherein when the rotation speed of the rotary polygon mirror is changed from the first rotation speed to the second rotation speed, the rotation control unit switches the masking processing from the first masking processing to the second masking processing after reduction of the rotation speed of the rotary polygon mirror is started.

Abstract: A CPU controls an image forming unit such that toner images for density detection are formed in parallel in a scanning direction of light beam under an image forming condition in which a period of time in which the light beam are emitted per unit time is changed and sets a target light amount of the light beam based on density information of the toner images for density detection formed by the image forming unit and relational data stored in a ROM.

Abstract: An image forming apparatus operable at a plurality of image forming speeds includes a pattern detection unit configured to detect a registration correction pattern at a first image forming speed, a writing start timing determination unit configured to determine writing start timing at which an electrostatic latent image is started to be written on a photosensitive member by a light beam emitted from a light source, and a storage unit configured to store in advance a correction amount for correcting the writing start timing. When the image forming apparatus operates at the first image forming speed set in advance, an image is formed at the writing start timing determined by the writing start timing determination unit. When the image forming apparatus operates at a second image forming speed, an image is formed at a writing start timing corrected based on the correction amount and a speed ratio.

Abstract: An image forming apparatus including: a setting unit configured to set light intensity correction data stored in a storage unit according to an exposure position while a light beam is being scanned on a photosensitive member at a first scan speed; and a light intensity controller configured to control a light intensity based on the correction data set by the setting unit, wherein the setting unit calculates a light intensity correction data corresponding to a position between a plurality of positions based on the stored correction data, set the correction data according to the exposure position while the light beam is being scanned at a second scan speed lower than the first scan speed; and fixes a switching period for switching the correction data according to the exposure position while the light beam is being scanned on an image forming area of the photosensitive member regardless of the scan speed.

Abstract: A CPU controls an image forming unit such that toner images for density detection are formed in parallel in a scanning direction of light beam under an image forming condition in which a period of time in which the light beam are emitted per unit time is changed and sets a target light amount of the light beam based on density information of the toner images for density detection formed by the image forming unit and relational data stored in a ROM.

Abstract: An image forming apparatus operable at a plurality of image forming speeds includes a pattern detection unit configured to detect a registration correction pattern at a first image forming speed, a writing start timing determination unit configured to determine writing start timing at which an electrostatic latent image is started to be written on a photosensitive member by a light beam emitted from a light source, and a storage unit configured to store in advance a correction amount for correcting the writing start timing. When the image forming apparatus operates at the first image forming speed set in advance, an image is formed at the writing start timing determined by the writing start timing determination unit. When the image forming apparatus operates at a second image forming speed, an image is formed at a writing start timing corrected based on the correction amount and a speed ratio.

Abstract: An image forming apparatus including: a setting unit configured to set light intensity correction data stored in a storage unit according to an exposure position while a light beam is being scanned on a photosensitive member at a first scan speed; and a light intensity controller configured to control a light intensity based on the correction data set by the setting unit, wherein the setting unit calculates a light intensity correction data corresponding to a position between a plurality of positions based on the stored correction data, set the correction data according to the exposure position while the light beam is being scanned at a second scan speed lower than the first scan speed; and fixes a switching period for switching the correction data according to the exposure position while the light beam is being scanned on an image forming area of the photosensitive member regardless of the scan speed.

Abstract: An image forming apparatus including: a drive motor configured to rotate a rotary polygon mirror to deflect light beam; a signal generation unit configured to generate a rotation synchronous signal; and a rotation control unit configured to control a rotation speed of the rotary polygon mirror, wherein the rotation control unit executes a disabling processing of disabling control of the drive motor based on the rotation synchronous signal, wherein a term of a first disabling processing for a first rotation speed is shorter than a term of a second disabling processing for the second rotation speed, and wherein when the rotation speed of the rotary polygon mirror is changed from the first rotation speed to the second rotation speed, the rotation control unit switches the disabling processing from the first disabling processing to the second disabling processing after reduction of the rotation speed of the rotary polygon mirror is started.

Abstract: An image forming apparatus comprises a semiconductor laser for emitting laser light for irradiating a photosensitive drum, BD for detecting laser light before irradiating the photosensitive drum to output BD signal as a reference for determining an initiation position of the photosensitive drum, and a laser circuit board. The laser circuit board causes the semiconductor laser to emit laser light detected by the BD with first light amount. When a BD sensor outputs the BD signal, a laser circuit board causes the semiconductor laser to emit the laser light with second light amount.

Abstract: An image forming apparatus that is capable of simplifying controls for light sources. A polygon mirror with four reflective surfaces deflects light beams emitted from first and second light sources. A housing in which the light sources and the polygon mirror are arranged is configured so that optical paths of the light beams toward the polygon mirror are parallel to a virtual plane containing a rotating axis of the polygon mirror, and so that the light beams are incident on adjoining reflective surfaces of the polygon mirror. First and second driver ICs drive the first and second light sources in one of operation modes. A control unit outputs the same operation mode signal to the first and second driver ICs at the same timing so that the first and second light sources operate in the same operation mode.

Abstract: A light scanning device that performs rapid scanning synchronization timing detection to thereby enable automatic light amount control to be executed rapidly and with high accuracy. A light amount sensor disposed on a scanning line of the laser light receives the laser light. A controller controls the timing of emission by the laser emitting device and a light amount of the laser light based on image data, according to an output from the light amount sensor. A temperature sensor detects the temperature of the laser emitting device or in the light scanning device. A storage section stores data indicative of a relationship between temperature, current supplied to the laser emitting device, and light amount. A controller controls current to be supplied to the laser emitting device based on temperature detected by the temperature detecting unit and data stored in the storage section.

Abstract: An image forming apparatus that is capable of simplifying controls for light sources. A polygon mirror with four reflective surfaces deflects light beams emitted from first and second light sources. A housing in which the light sources and the polygon mirror are arranged is configured so that optical paths of the light beams toward the polygon mirror are parallel to a virtual plane containing a rotating axis of the polygon mirror, and so that the light beams are incident on adjoining reflective surfaces of the polygon mirror. First and second driver ICs drive the first and second light sources in one of operation modes. A control unit outputs the same operation mode signal to the first and second driver ICs at the same timing so that the first and second light sources operate in the same operation mode.

Abstract: Since a photodiode (PD) is disposed in the vicinity of the plurality of light emitting elements and, therefore, the PD also receives a laser beam emitted only by a bias current during the APC period, setting a bias current based on a result of light amount detection by the PD does not result in a bias current setting with sufficient accuracy. To solve this issue, an electrophotographic image forming apparatus forms an electrostatic latent image pattern on a photosensitive drum, and controls the value of the bias current set for a first light emitting element based on the potential of the electrostatic latent image pattern and a detecting result of the PD.

Abstract: First and second light amount detection elements are arranged on a scanning line of a laser beam. The first light amount detection element receives a laser beam having a first light amount, and the second light amount detection element receives a laser beam having a second light amount that is lower than the first light amount. The detection signal that is output by the second light amount detection element is amplified by an amplifier and used as a synchronization signal. Here, an amplification factor of this amplifier is greater than an amplification factor of another amplifier for amplifying the detection signal that is output by the first light amount detection element. The detection signals amplified by the amplifiers are modified by a modification coefficient that correspond to the amplification factors, and used as signals that indicate the light amounts.