Abstract: An image forming apparatus includes: an image carrier that rotates and carries a toner image by a surface layer disposed on a surface thereof; a charging roll that charges the surface layer while the image carrier completes one or more rotations; a power supply unit that supplies a current to the charging roll; a detector that samples and detects the current that the power supply unit outputs; a leak current detector that detects a leak current included in the current that the detector has detected; a layer thickness calculating unit that calculates a numerical value relating to the thickness of the surface layer on the basis of the current that the detector has detected; and a current leak state determining unit that determines a current leak state on the basis of the current that the detector has detected and the leak current that the leak current detector has detected.

Abstract: A charging device includes a charging member that charges a body to be charged; a detector that detects an AC component of a current flowing through the charging member; an integration section that integrates the AC component of the current detected by the detector; a controller that controls the current flowing through the charging member, according to a result of integration executed by the integration section; a periodic signal generating section that generates a periodic signal having a cycle period corresponding to a cycle period of the AC component; and an integration period adjusting section that adjusts a period of integration executed by the integration section, with reference to the periodic signal.

Abstract: In case of driving each of light emitting parts of a surface emitting laser, each of light emitting parts is made to be in forward-bias state and switches appropriately change bias voltage, which is lower than laser oscillation threshold voltage, and drive voltages, which are not less than the laser oscillation threshold voltage to directly apply the changed voltage to each of drive ends of the light emitting parts. Whereby, each of light emitting parts is driven.

Abstract: A total layer thickness detection apparatus for a charged body includes: a saturated charge amount detection unit that detects a saturated charge amount of a charged body having plural coating layers with mutually different relative dielectric constants; a storage unit that stores relation information indicating relation of change of the saturated charge amount of the charged body with respect to a change of layer thickness of a surface layer of the charged body; and a calculation part that calculates a total layer thickness of the plural coating layers of the charged body based on the change of the saturated charge amount detected by the saturated charge amount detection unit and the relation information stored in the storage unit.

Abstract: An image forming apparatus, includes: an image carrier that carries a developer image by a charge layer provided on a surface of the image carrier; a charger that charges the image carrier; a feeder that feeds the charger with a charge; a total charge amount detector that detects the total amount of the charge output by the feeder; an unsupplied charge amount calculator that calculates the amount of the charge output by the feeder but not supplied to the charger; and a layer thickness calculator that calculates the thickness of the charge layer based on the unsupplied charge amount calculated by the unsupplied charge amount calculator and the total charge amount detected by the total charge amount detector.

Abstract: An image forming apparatus including a photoreceptor that rotates, a charging member provided in contact with or in close proximity of the photoreceptor to charge the photoreceptor, a charge amount detecting portion that accumulates current flowing across the photoreceptor to obtain a charge amount of the photoreceptor, while the current is being applied from the charging member until a voltage on a surface of the photoreceptor substantially corresponds to the voltage applied by the charging member, and a controller that calculates a film thickness of the photoreceptor based on the charge amount.

Abstract: A charging device includes a charging member that charges a body to be charged; a detector that detects an AC component of a current flowing through the charging member; an integration section that integrates the AC component of the current detected by the detector; a controller that controls the current flowing through the charging member, according to a result of integration executed by the integration section; a periodic signal generating section that generates a periodic signal having a cycle period corresponding to a cycle period of the AC component; and an integration period adjusting section that adjusts a period of integration executed by the integration section, with reference to the periodic signal.

Abstract: In case of driving each of light emitting parts of a surface emitting laser, each of light emitting parts is made to be in forward-bias state and switches appropriately change bias voltage, which is lower than laser oscillation threshold voltage, and drive voltages, which are not less than the laser oscillation threshold voltage to directly apply the changed voltage to each of drive ends of the light emitting parts. Whereby, each of light emitting parts is driven.

Abstract: An image forming apparatus includes: a photoconductor having a photoconductive layer on an outer surface thereof; a charging portion that charges the photoconductor; a developing portion that develops a latent image formed on the photoconductor; a transfer portion that transfers a developed image; current detectors respectively provided to the charging portion, the developing portion, and the transfer portion to detect currents respectively flowing from the charging portion, the developing portion, and the transfer portion to the photoconductor; an integrating portion that calculates a charge amount by integrating the currents detected by the current detectors over a given period of time; and a layer thickness calculating portion that calculates a thickness of the photoconductive layer based on the charge amount.

Abstract: An image forming apparatus includes: an image carrier that rotates and carries a toner image by a surface layer disposed on a surface thereof; a charging roll that charges the surface layer while the image carrier completes one or more rotations; a power supply unit that supplies a current to the charging roll; a detector that samples and detects the current that the power supply unit outputs; a leak current detector that detects a leak current included in the current that the detector has detected; a layer thickness calculating unit that calculates a numerical value relating to the thickness of the surface layer on the basis of the current that the detector has detected; and a current leak state determining unit that determines a current leak state on the basis of the current that the detector has detected and the leak current that the leak current detector has detected.

Abstract: An image forming apparatus, includes: an image carrier that carries a developer image by a charge layer provided on a surface of the image carrier; a charger that charges the image carrier; a feeder that feeds the charger with a charge; a total charge amount detector that detects the total amount of the charge output by the feeder; an unsupplied charge amount calculator that calculates the amount of the charge output by the feeder but not supplied to the charger; and a layer thickness calculator that calculates the thickness of the charge layer based on the unsupplied charge amount calculated by the unsupplied charge amount calculator and the total charge amount detected by the total charge amount detector.

Abstract: A light-emitting device driver that includes a driver unit that drives a light-emitting device, a compensator that compensates for at least one of the rising and falling responses of the driver unit, a switching unit that switches on and off the compensator, and a control unit that performs on/off control on the switching unit.

Abstract: An image forming apparatus including a photoreceptor that rotates, a charging member provided in contact with or in close proximity of the photoreceptor to charge the photoreceptor, a charge amount detecting portion that accumulates current flowing across the photoreceptor to obtain a charge amount of the photoreceptor, while the current is being applied from the charging member until a voltage on a surface of the photoreceptor substantially corresponds to the voltage applied by the charging member, and a controller that calculates a film thickness of the photoreceptor based on the charge amount.

Abstract: In case of driving each of light emitting parts of a surface emitting laser, each of light emitting parts is made to be in forward-bias state and switches appropriately change bias voltage, which is lower than laser oscillation threshold voltage, and drive voltages, which are not less than the laser oscillation threshold voltage to directly apply the changed voltage to each of drive ends of the light emitting parts. Whereby, each of light emitting parts is driven.

Abstract: A light-emitting device driver that includes a driver unit that drives a light-emitting device, a compensator that compensates for at least one of the rising and falling responses of the driver unit, a switching unit that switches on and off the compensator, and a control unit that performs on/off control on the switching unit.

Abstract: In case of driving each of light emitting parts of a surface emitting laser, each of-light emitting parts is made to be in forward-bias state and switches appropriately change bias voltage, which is lower than laser oscillation threshold voltage, and drive voltages, which are not less than the laser oscillation threshold voltage to directly apply the changed voltage to each of drive ends of the light emitting parts. Whereby, each of light emitting parts is driven.

Abstract: The object of the present invention is to precisely correct the luminous energy of a laser beam on a scanned surface which varies according to scanning and varies according to an angle of incidence with the scanned surface when a laser beam emitted from a semiconductor laser for emitting a laser beam having luminous energy according to supply current is scanned on the scanned surface via a scanning optical system.

Abstract: A signal processor amplifies picture signals provided by an image sensor, samples the amplified picture signals and holds the samples of the amplified picture signals. The signal processor comprises a dual correlation sampling circuit, and a sample-and-hold circuit connected to the output part of the dual correlation sampling circuit. The dual correlation sampling circuit comprises an amplifying stage to which an input signal is given, a low-pass filter connected to the output part of the amplifying stage, a time constant changing switch to be closed to set the low-pass filter for a smaller time constant, and a switch driving means for closing the time constant changing switch after the completion of giving an input signal to the amplifying stage.

Abstract: The present invention relates to a semiconductor laser drive device, and an image recording device whose function includes scanning a predetermined body to be scanned with a laser beam carrying image information in the course of recording an image, and which makes high speed image regeneration while maintaining a high quality of the image, wherein the devices are equipped with a first feedback circuit including a first operational amplifier and a second feedback circuit including a second operational amplifier, so that the double feedback can concurrently be effected to obtain current vs. light output characteristics with a high speed and high accuracy in an analog mode.

Abstract: The present invention relates to a laser diode driving circuit for supplying a drive current to a laser diode, a semiconductor integrated circuit for driving the laser diode, and an image recording apparatus in which a step of executing a scanning on a predetermined member to be scanned with a laser beam holding image information is included in an image recording step. The laser diode is certainly kept in a no light emitting state at a timing when the laser diode should be kept in the no light emitting state and is allowed to emit a laser beam of the light quantity faithfully corresponding to the drive current at a timing when the drive current is supplied to the laser diode. A bias current out of the bias current and a drive current which are supplied to a laser diode 1 is further divided into a first bias current and a second bias current. Normally, only the first bias current is supplied to the laser diode. The second bias current is supplied and stopped in a manner similar to the drive current.