Abstract: An image forming apparatus causes a BD sensor to generate two BD signals based on laser beams emitted from first and second light-emitting portions and measures the generation timing difference therebetween. When measurement is to be executed, the image forming apparatus executes APC as light power control on the first light-emitting portion that emits a laser beam for causing the BD sensor 210 to generate the first BD signal. On the other hand, the image forming apparatus executes ACC, rather than APC, as light power control on the second light-emitting portion that emits a laser beam for causing the BD sensor to generate the second BD signal that follows the first BD signal.

Abstract: A determination unit determines a bias current caused to flow through at least plurality of light-emitting portions regardless of image data during an image period by determining a first drive current for setting a light quantity of a light beam incident on a light reception unit during the non-image period to a first target light quantity, and determining a second drive current for setting a light quantity of a light beam incident on the light receiving unit to a second target light quantity that is different from the first target light quantity. The determination unit determines a drive current for performing switch-driving of the plurality of light-emitting portions, based on image data, the drive current corresponding to the first drive current and the bias current upon the image data being generated in a second section of a non-image period.

Abstract: An image forming apparatus causes a BD sensor to generate two BD signals based on laser beams emitted from first and second light-emitting portions and measures the generation timing difference therebetween. When measurement is to be executed, the image forming apparatus executes APC as light power control on the first light-emitting portion that emits a laser beam for causing the BD sensor 210 to generate the first BD signal. On the other hand, the image forming apparatus executes ACC, rather than APC, as light power control on the second light-emitting portion that emits a laser beam for causing the BD sensor to generate the second BD signal that follows the first BD signal.

Abstract: An image forming apparatus, including: a laser light source supplied with a bias current and a superimposed current to emit laser light; a splitting unit configured to split the laser light into first and second laser lights; a photoelectric conversion unit configured to output a voltage corresponding to a light intensity of the second laser light; a voltage holding unit configured to hold a voltage output from the photoelectric conversion unit with not the superimposed current but the bias current being supplied to the laser light source; a voltage conversion unit configured to remove the voltage held by the voltage holding unit from the voltage from the photoelectric conversion unit which receives the second laser light; and a current control unit configured to control, based on a voltage from the voltage conversion unit, a value of the superimposed current supplied to the laser light source based on image data.

Abstract: A light beam scanning device which is capable of performing high-accuracy light amount control without complicated control even when the device includes a laser diode having non-linear I-L characteristics. Gain circuits set the amount of light to be emitted from the laser diode. A PD circuit board detects the amount of the emitted light. A laser controller controls the amount of the emitted light by adjusting drive current applied to the laser diode based on a detection output from the PD circuit board. A CPU corrects data for correcting the drive current. The CPU decides a light amount correction range for correcting the light amount based on the correction data, calculates the slope of the I-L characteristics in the light amount correction range based on light amounts at two points within the light amount correction range and drive currents associated with the respective light amounts, and corrects the correction data using the calculated slope.

Abstract: An exposure apparatus according to one aspect of this invention includes a plurality of laser light sources (LDs) each configured to output a laser beam of a light power corresponding to a supplied current. The exposure apparatus exposes the surface of a photosensitive drum with a plurality of laser beams. When determining the incident states of the laser beams on the light-receiving surface of a PD, a CPU controls at least one LD as a control target. The CPU causes the control target LD by a current of a predetermined magnitude to emit light and output a laser beam. Based on a light power detection value from the PD for a laser beam output from the control target LD, the CPU determines the incident state of the laser beam on the light-receiving surface of the PD.

Abstract: A laser drive device capable of easily reducing influence of bias light emission and thereby preventing variation in threshold current. A light amount of a laser beam emitted from a laser diode is detected by a photodiode. A drive current supplied to the laser diode is controlled according to the detected light amount to thereby control the amount of light emitted from the laser diode to a plurality of set light amounts. A threshold current is calculated according to the detected light amount and the drive current. The light amounts are changed and selected, and threshold currents calculated with respect to respective set light amounts are compared. A light amount corresponding to a difference in threshold current not less than a predetermined value is set as a set light amount for use in light amount control of the laser diode.

Abstract: A light beam scanning device which is capable of performing high-accuracy light amount control without complicated control even when the device includes a laser diode having non-linear I-L characteristics. Gain circuits set the amount of light to be emitted from the laser diode. A PD circuit board detects the amount of the emitted light. A laser controller controls the amount of the emitted light by adjusting drive current applied to the laser diode based on a detection output from the PD circuit board. A CPU corrects data for correcting the drive current. The CPU decides a light amount correction range for correcting the light amount based on the correction data, calculates the slope of the I-L characteristics in the light amount correction range based on light amounts at two points within the light amount correction range and drive currents associated with the respective light amounts, and corrects the correction data using the calculated slope.