Abstract: An image forming apparatus includes a control unit configured to form electrostatic latent images for correction on a photosensitive member a voltage application unit configured to apply a voltage to a process unit; a current detection unit configured to detect a current to the voltage application unit via the process unit when the voltage is applied to the process unit; and a conversion unit configured to convert an output value detected by the current detection unit such that a variation range of the output value detected by the current detection unit at a formation period of the electrostatic latent image for correction becomes larger than a variation range of the output value detected by the current detection unit at a one-rotation period of the photosensitive member on which the electrostatic latent image is not formed.

Abstract: An image forming apparatus includes an exposure unit configured to form a latent image by irradiating a charged photosensitive member with light, and a control unit configured to cause the exposure unit to expose an image portion to which toner of the photosensitive member is to be adhered by a first exposure amount, and expose a non-image portion to which the toner of the photosensitive member is not to be adhered by a second exposure amount which is smaller than the first exposure amount. The control unit corrects the preset second exposure amount based on information about a difference between the charging voltage output from the charging unit and a predetermined charging voltage and/or information about a difference between the developing voltage output from the developing unit and a predetermined developing voltage.

Abstract: An anamorphic optical element and an adjustment mechanism for selectively rotating the optical element either around an axis substantially in a vertical direction, an axis substantially in an optical axis direction, an axis substantially in a plane formed by the vertical direction and the optical axis direction, or combination of axes thereof is used to vary a vertical separation between two or more spots.

Abstract: An image forming apparatus includes: a density detection unit that detects densities of an image developed by a developing unit at a plurality of positions in a main-scanning direction; a processing unit that obtains at least one of an amplitude and a phase of a first periodical density change of the image, of which cycle is a rotation cycle of a photosensitive drum, at the plurality of positions in the main-scanning direction on the basis of an output signal of the density detection unit, and corrects a drive signal for the light source so as to suppress the first periodical density change of the image at each position in the main-scanning direction on the basis of the rotation cycle of the photosensitive drum and at least one of the amplitude and the phase.

Abstract: An optical writing device includes: a photosensitive element whose surface relatively moves with respect to a light source by rotation; a pixel information acquiring unit that acquires pixel information of an image to be formed on the photosensitive element as an electrostatic latent image; a line pixel information storing unit that stores the pixel information for every main scanning line; a light emission control unit that causes a light source to emit light based on the pixel information; a rotation position recognizing unit that recognizes a rotation position of the photosensitive element; and a light quantity control unit that controls a light quantity of the light source based on the pixel information of every one main scanning line in accordance with the rotation position, with reference to correction value information in which the rotation position and information related to a correction of the light quantity are associated.

Abstract: An image forming apparatus includes; an exposure unit configured to perform, based on the image data, first exposure for a photosensitive member and second exposure for the photosensitive member exposed by the first exposure; a determination unit configured to determine a type of the image to be formed based on image data; and a control unit configured to control the exposure unit such that a difference in an exposure amount between the first exposure and the second exposure performed based on the image data when the type of the image is a character is larger than the difference in the exposure amount between the first exposure and the second exposure performed based on the image data when the type of the image is a picture.

Abstract: An image forming apparatus and a control method include a photosensitive unit having a photosensitive drum, an exposure unit to form an electrostatic latent image on the photosensitive drum, a developing unit to form a toner image by sequentially supplying a plurality of color toners to the electrostatic latent images formed on the photosensitive drum, an intermediate transfer unit having an intermediate transfer belt to perform a first transfer of the toner image formed on the photosensitive drum in a sequential manner by color, a transfer roller configured to perform a second transfer of the toner image on a printing medium , a transfer belt cleaning unit to perform a cleaning task to remove a waste toner that remains on the intermediate transfer belt after the second transfer is performed, and a control unit to start performing idling of the intermediate transfer belt when an exposure with respect to one page toner image is completed and the first transfer is in progress, and to start the second transfer b

Abstract: An image forming apparatus includes an image bearing member that bears a developer image, a transfer apparatus that transfers the developer image, a charge apparatus, an exposure apparatus that exposes the surface of the image bearing member with light to form a latent image, and a developing apparatus that collects and supplies the developer to the latent image to form the developer image, in which an image formation area is divided into an image part and a non-image part where the developer image is not formed, the exposure apparatus exposes the non-image part with light at an exposure amount lower than an exposure amount with respect to the image part, and the charging apparatus charges the image bearing member and the exposure apparatus exposes the image part and the non-image part with light in a state in which the developer remains on the image bearing member.

Abstract: An image forming apparatus includes: an image forming section including a light exposure section configured to expose an image bearing member to light to form an electrostatic latent image, the image forming section being configured to form a toner image on the image bearing member, and to form an image on a recording sheet by transferring the toner image onto the recording sheet; an estimation section configured to estimate a density lowering position on the basis of image data of an image formed by the image forming section, the density lowering position being a position where decrease in image density relative to a predetermined image density is caused in the image; and a control section configured to increase a light exposure amount at the density lowering position estimated by the estimation section on the image bearing member to an amount greater than a predetermined light exposure amount.

Abstract: An image forming apparatus including: a photoreceptor; a charger configured to charge a photoreceptor surface; an optical scanning device configured to expose the photoreceptor surface to form an electrostatic latent image thereon; a developing device configured to develop the electrostatic latent image to form a toner image thereon; a transfer member configured to transfer the toner image to a sheet; a fixing device configured to fix the toner image thereon; and a control unit configured to carry out exposure amount control for formation of an image having a pattern with a spatial frequency from 0.1 c/mm to 3.0 c/mm so that after the exposure, there will be an electric potential difference V1 between an edge portion and a non-edge portion of the pattern and so that there will be an electric potential difference V2 larger than V1 between an edge-surrounding portion and the other portions of a non-image area.

Abstract: Provided is a color image forming apparatus which has photosensitive members and a light irradiation unit irradiating at least one of the photosensitive members, the color image forming apparatus including: a laser driving unit causing the light irradiation unit to emit light of a light amount at a first emission level for printing when exposing an image portion and to emit light of a light amount at a second emission level for weak emission when exposing a non-image portion; an acquiring unit acquiring information of remaining lifetime of each of the photosensitive members; a first light intensity adjusting unit adjusting a first drive current to emit light at the first emission level; and a second light intensity adjusting unit adjusting a second drive current to emit light at the second emission level, the second light intensity adjusting unit changing the second drive current in accordance with the information.

Abstract: An image formation apparatus includes an exposure unit to form an electrostatic latent image with image dots on a rotatable image carrier by exposing the image carrier to irradiation light, a development unit to form a developer image by attaching a developer to the electrostatic latent image, a voltage supply unit to supply the development unit with a development voltage, a cleaning unit to clean up the developer left on the image carrier after the development, and a developer discard amount controller to control an amount of the developer to be forcibly attached to the image carrier based on a total rotation number of the image carrier if the number of image dots printed during a prescribed number of rotations of the image carrier is smaller than a reference value, and to forcibly attach the controlled amount of the developer to the image carrier to discard the developer.

Abstract: In an image forming apparatus, in the case where a time necessary for a developer bearing member to rotate from a measurement position where an attracting unit attracts the toner on the developer bearing member to a developing position at which an electrostatic latent image on the photosensitive member is developed by a toner on the developer bearing member is represented by a time Tqcm, a time necessary for the photosensitive member to rotate from an exposure position at which an exposure unit exposes the photosensitive member to the developing position is represented by a time Tetd, and a time necessary for a control unit to control an exposing condition based on a charge amount measured by a measuring unit is represented by a time Tp, the attracting unit is disposed so that Tqcm?Tedt+Tp holds true.

Abstract: An image forming apparatus includes temperature sensors that measure temperatures at different locations in the longitudinal direction of a photosensitive drum. The image forming apparatus also includes an image processing circuit configured to change an exposure condition in the longitudinal direction of the photosensitive drum based on measured values obtained by the temperature sensors. A related image forming method includes calculating a temperature at a third location between the first and second location based on the measured temperatures at the first location and the second location, and controlling an exposure condition for exposure at the third location in accordance with image information, including changing the exposure condition for the exposure at the third location based on the calculated temperature at the third location.

Abstract: An image forming apparatus and a method of setting an exposure amount are provided. The image forming apparatus includes a photosensitive member, an exposure device which expose the photosensitive member to form a latent image on the photosensitive member, a conveyance member which conveys a recording medium, an image forming unit which forms a plurality of density detection images corresponding to the image data and having different pixel densities on the conveyance member, a density detection unit which detects densities of the density detection images, and an exposure setting unit which compares respective detected image densities of the density detection images with reference densities corresponding to the respective density detection images, and sets an exposure amount according to a condition based on a combination of respective comparison results between the detected image densities and the reference densities.

Abstract: An image forming apparatus is provided. The image forming apparatus includes a plurality of photosensitive members arranged to align in parallel with one another, an exposure device arranged in an upper position with respect to the plurality of photosensitive members and configured to expose the photosensitive members to light, an exposure controller arranged in an upper position with respect to the exposure device and configured to control the exposure device according to inputted image data, a power board, arranged in a lower position with respect to the plurality of photosensitive members and configured to convert alternate current power to direct current power, and a voltage converter arranged in un upper position with respect to the exposure device and configured to convert the direct current power supplied from the power board into an at least single-leveled first voltage and supply the first voltage to the exposure controller.

Abstract: An image reading apparatus capable of reading documents includes a reading unit including a light emitting element, a mechanism configured to move the reading unit, and a control unit configured to control the reading unit and the mechanism both to carry out reading by turning on the light emitting element and moving the reading unit and to temporarily stop moving the reading unit upon occurrence of a predetermined factor. The control unit sets a first current value which is caused to flow through the light emitting element when reading is carried out and sets a second current value which is less than the first current value and which is caused to flow through the light emitting element when the reading unit is temporarily stopped.

Abstract: A system and method for reducing scan line jitter in laser scan systems employing a rotating mirror, including a controller for determining a unique time delay for each mirror facet and controlling laser sources so that video provided by each laser source is delayed in a scan line by the unique time delay corresponding to the mirror facet used in creating the scan line. The controller computes a facet map signature vector corresponding to each mirror facet matches the signature to a previously stored signature and assigns measured distance offset data to the mirror facets based upon the matching.

Abstract: Printers are provided in which a charge pattern is formed with a first area having a surface potential that is at least 30 percent less than a surface potential of an adjacent second area that creates an inter-area field between the first area and second area that extends into a portion of the first area that is proximate to the second area. A development station applies a first development field and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and first toner are further developed with a different second toner. The surface charge, the first toner and second toner have the same polarity.

Abstract: An image forming apparatus having: a light source that emits a beam; a photoreceptor that is scanned with the beam to obtain an electrostatic latent image thereon; and a control unit that determines a light intensity of the beam to be emitted for formation of a pixel, based on a data value for the pixel in image data and data values for its surrounding pixels.

Abstract: Certain embodiments provide an image forming apparatus including: an image carrier; a latent image forming unit; a developing unit; a fixing unit; a toner cartridge; a battery in the toner cartridge; a temperature sensor in the toner cartridge driven by the battery; a first controller which causes the temperature sensor to measure an ambient temperature periodically in the toner cartridge and be supplied with power from the battery; a recording medium which is provided in the toner cartridge and records a result of measurement by the temperature sensor in timing controlled by the first controller; and a second controller which reads out information recorded in the recording medium, and changes an operating condition of the latent image forming unit, the developing unit and the fixing unit according to a state of preservation of the supply of toner, based on the information.

Abstract: An image forming apparatus including: a photosensitive member; a charging device; an exposure device; and a developer carrying member, wherein, when it is assumed that an image forming area, a printing portion and a non-printing portion are an area on the photosensitive member on which an image to be transferred onto a recording material is formed, an area in the image forming area to which the developer adhere and an area in the image forming area to which the developer does not adhere, respectively, the exposure device exposes the printing portion at a first laser power, exposes the non-printing portion at a second laser power smaller than the first laser power, and exposes a non-image forming area on the photosensitive member between two adjacent image forming areas at no laser power or a third laser power smaller than the second laser power.

Abstract: An image forming apparatus includes an exposure device configured to expose image bearing members charged by charging devices to form latent images on the image bearing members, and a control unit configured to, in ether one or both of an image forming unit A and an image forming unit B, adjust an amount of exposure by which the image bearing member is exposed and a charging voltage based on information about the image bearing members of the image forming units A and B. The control unit is configured to make the charging voltage and the amount of exposure in the image forming unit A different from the charging voltage and the amount of exposure in the image forming unit B.

Abstract: The apparatus includes a CPU which executes, based on a detection result of a BD sensor, start-up control for controlling driving of a scanner motor, so that a rotation number of the scanner motor reaches a predetermined rotation number, and executes determination control for determining a voltage to be applied to a primary transfer unit based on a detection result of a transfer current detection circuit by a transfer voltage output circuit upon execution of image formation, and when an image forming station K which executes image formation is different from an image forming station Y including the BD sensor, the CPU parallelly executes the start-up control and determination control.

Abstract: An image scanner includes: a light source that irradiates, with light, a recording medium on which an image is formed; a light receiving portion that receives light reflected by the recording medium; a generating portion that generates a light amount value from the light received by the light receiving portion; a measuring portion in which plural reflecting surfaces are disposed, the reflecting surfaces respectively having predetermined colors different from each other; and a processing portion that derives a correlation formula from a light amount value generated at predetermined reference time and from a light amount value generated when the reflecting surfaces in the measuring portion are irradiated with the light from the light source, the correlation formula expressing a time-varying change in the light source.

Abstract: An image forming apparatus includes image forming portion, toner-disposal container, conveying portion, driving portion, load detection portion, image formation control portion, and image forming condition adjustment portion. The image forming condition adjustment portion corrects, when image forming condition does not conform to predetermined condition, the image forming condition. In a case where a drive load detected by the load detection portion becomes greater than first threshold value while the conveying portion is driven by the driving portion and the image forming operation is executed, the image formation control portion temporarily stops the image forming operation, and causes the image forming condition adjustment portion to check and correct the image forming condition.

Abstract: An image forming apparatus including: photosensitive members; charging devices to which a common charging power source applies a charging voltage to charge the photosensitive members; an exposure device configured to expose the photosensitive members; developing devices to form developer images on the photosensitive members; a transfer device to transfer the developer images onto a transfer medium; and a control portion configured to set a lower limit value of the charging voltage for each photosensitive member, apply the charging voltage having a magnitude not less than any lower limit value from the charging power source to the charging devices, control the output of the laser power for each photosensitive member individually, and set, based on the image density of the developer image transferred onto the transfer medium earlier, the lower limit value for a photosensitive member on which a developer image to be transferred onto the transfer medium later is formed.

Abstract: An exposure adjusting apparatus, which comprises: an image sensor, for catching an image according to an exposure parameter; a computing apparatus, for computing an exposure amount of the image and for determining whether the exposure amount is in a predetermined exposure range or not; and an exposure updating apparatus. If the exposure amount is in the predetermined exposure range, the exposure updating apparatus does not adjust the exposure amount. If the exposure amount is not in the predetermined exposure range, the exposure updating apparatus generates at least one adjusting amount according to at least one of the predetermined exposure range, the exposure amount and the exposure parameter, and utilizes the adjusting amount to increase or decrease the exposure parameter to generate a new exposure parameter.

Abstract: An optical scanning device includes a MEMS mirror, a driving unit for oscillating the MEMS mirror using a drive voltage which varies in a basic cycle, a light detection unit for receiving laser light deflected by the MEMS mirror and outputting a detection signal, a correction value calculation unit for calculating a correction voltage value used in correcting the drive voltage, a DC voltage generation unit for generating a DC voltage having a voltage value smaller than the correction voltage value, a DC voltage amplification unit for amplifying the DC voltage generated by the DC voltage generation unit to have a voltage value equal to the correction voltage value, and a waveform shaping unit for shaping the waveform of the amplified DC voltage so that the DC voltage varies in the basic cycle and outputting the shaped DC voltage as the drive voltage to the driving unit.

Abstract: An image forming apparatus includes: a charging unit that uniformly charges a surface of a latent image carrier; a latent-image forming unit; a developing unit that performs development by causing toner to electrostatically adhere on the surface of the carrier; a transfer unit that transfers a toner image onto a recording medium; and an image-density adjusting unit that causes to form a multi-gradation patch pattern on the surface of the carrier, that causes to detect potentials of latent image patches in the multi-gradation patch pattern, that causes to detect a toner adhesion amount on each toner patch, and that performs control of an image density. One of part and all of the low-density latent image patches is a dot-dispersed latent image patch in which the arrangement of unit dot latent images in the basic dot matrix is determined so that a minimum center-to-center distance having a smallest value is maximized.

Abstract: An image forming apparatus may include a first and second mode. In the first mode, the image forming apparatus uses a second charging member to charge toner that remains on an intermediate transfer member and then transfers the charged, remaining toner to an image carrier in a primary transfer portion. In the second mode, the image forming apparatus transfers the remaining toner adhered to the second charging member in the first mode to the intermediate transfer member. Also in a second mode, the image forming apparatus controls so that a surface potential of the image carrier that reaches the primary transfer portion at a timing at which the remaining toner transferred to the intermediate transfer member passes through the primary transfer portion has a same polarity as that of a surface potential of the image carrier in the first mode and also has an absolute value smaller than that thereof.

Abstract: An imaging device having a printhead unit which includes a plurality of independently controllable light sources, each light source generating a light beam when activated; a photoconductive surface operable at a plurality of image transfer rates; a scanning device having one or more deflecting surfaces, the scanning device arranged to direct the light beams so as to sweep in at least one scan direction across a surface such that, for each sweep, scan lines written by the light beams are spaced from one another on the photoconductive surface in a process direction that is nominally orthogonal to the scan direction; and a controller configured to selectively activate any number of the light sources for use during a print operation to write image data along scan lines on the photoconductive surface, wherein a rotational velocity of the scanning device is selected and the number of the light sources activated based upon at least one selected operating parameter for the imaging device.

Abstract: An image forming apparatus includes an exposure unit configured to form a latent image by irradiating a charged photosensitive member with light, and a control unit configured to cause the exposure unit to expose an image portion to which toner of the photosensitive member is to be adhered by a first exposure amount, and expose a non-image portion to which the toner of the photosensitive member is not to be adhered by a second exposure amount which is smaller than the first exposure amount. The control unit corrects the preset second exposure amount based on information about a difference between the charging voltage output from the charging unit and a predetermined charging voltage and/or information about a difference between the developing voltage output from the developing unit and a predetermined developing voltage.

Abstract: An image forming apparatus that is capable of reducing a sequential variation of graininess and keeping imaging quality. An exposure unit exposes the photoconductor to a light beam to form an electrostatic latent image. A development unit develops the electrostatic latent image with a toner. A change unit changes a height of toner image by changing an exposure spot area of the light beam on the photoconductor. A formation unit forms test patterns corresponding to different exposure spot areas on a recording sheet. A read unit reads the test patterns. A control unit detects graininess of each test pattern based on information about the test patterns read by the read unit, determines an exposure spot area where the graininess becomes good relatively, and controls the height of toner image on the photoconductor by setting the exposure spot area determined so as to be an exposure spot area for image formation.

Abstract: An image forming apparatus includes: a ground image producing unit which produces a ground image that determines a print position of an information image; a ground image printing unit which prints the ground image produced by the ground image producing unit, with a printing color material which does not have a sensitivity in a reading wavelength of a reading apparatus that reads the information image; and an information image printing unit which prints the information image at a print position that is determined by the ground image printed by the ground image printing unit.

Abstract: The present disclosure provides a method of forming a toner image, comprising: electrically charging a photoreceptor by a charging roller being brought into contact with the photoreceptor, the photoreceptor comprises a photosensitive coating layer on a cylindrical conductive substrate; correcting line width variation using an exposure adjustment calculation (y); and, wherein the exposure adjustment calculation uses a factor based on a ratio (m) of a coefficient of line width variation due to toner age divided by the coefficient of line width variation due to laser power.

Abstract: An image forming device includes each of developing devices including an image carrying part, a charging part that charges the image carrying part, a developing part on which a developing voltage is applied and which attaches developer to the image carrying part to develop the electrostatic latent image, and a control part that controls each of the developing devices. The developers are a white developer and other color developers, one of the developing devices using the white developer being defined the white developing device, the others using the other color developers being defined the non-white developing devices, and a developing potential difference of the white developing device is smaller than other developing potential differences of the non-white developing devices, the developing potential difference being defined between the developing voltage and potential of the image carrying part of the each developing device.

Abstract: An image forming apparatus includes an intermediary transfer member having an elastic layer; a toner image forming portion for forming a toner image for an image to be carried on the intermediary transfer member; a transfer member, which presses the intermediary transfer member, for transferring the toner image for the image from the intermediary transfer member onto a recording material; a pressing mechanism capable of changing pressure applied from the transfer member to the intermediary transfer member; and a controller for controlling the toner image forming portion so that a length of the toner image for the image on the intermediary transfer member with respect to a rotational direction of the intermediary transfer member is decreased with an increase of the pressure.

Abstract: An image forming apparatus has an image carrier carrying an electrostatic latent image, a charging unit charging the surface of the image carrier, an exposure unit forming an electrostatic latent image by irradiating light onto the charged surface of the image carrier, a developing unit developing the electrostatic latent image formed on the surface of the image carrier using a developing material, and a transfer unit transferring a developer image onto a printing material. The apparatus has also an image correction unit correcting image data inputted to the exposure unit so as to compensate for deformation in the developer image originating in a form of the exposure unit, and a smoothing processing unit carrying out smoothing of an image by controlling the exposure unit so that dots of a size smaller than one pixel are filled with respect to a white image region of the corrected image data.

Abstract: A drive circuit is provided for supplying a drive current to drive a plurality of driven elements. The drive circuit includes a switch circuit having an input terminal for receiving a drive signal alternately changing between an on state and an off state, and an output terminal connected to the driven elements; and a constant current circuit connected to the switch circuit for adjusting the drive current at a constant level. The constant current circuit is formed of a depletion type MOS transistor.

Abstract: An image forming apparatus includes photosensitive drums, charging devices, an exposure unit configured to expose surfaces of photosensitive drums to generate a non-image portion potential and expose the surfaces to generate an image portion potential, developing members configured to make a developer adhere to an area where the image portion potential is generated to form a developer image on the photosensitive drums, a control unit configured to control an intensity of the charging voltage, and an acquisition unit configured to acquire thicknesses of photosensitive layers of the respective plurality of photosensitive drums, wherein the control unit is configured to set the intensity of a charging voltage applied to the common charging devices according to a maximum thickness among the thicknesses acquired by the acquisition unit, and individually control the output of the first laser power for the photosensitive drum according to surface potentials of the charged photosensitive drums.

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: The image forming apparatus is capable of executing a color mode for forming images of a plurality of colors using the plurality of developer bearing members, and a mono-mode for forming images of mono color using one developer bearing member of the plurality of developer bearing members. The control unit, when the color mode is executed, determines the charging bias and, the first laser power and the second laser power for respective image bearing members, based on information about the plurality of image bearing members. The control unit, when the mono-mode is executed, determines the charging bias and, the first laser power and the second laser power to image bearing member for mono-mode, based on information about image bearing member for mono-mode.

Abstract: An image formation apparatus includes an exposure unit to form an electrostatic latent image with image dots on a rotatable image carrier by exposing the image carrier to irradiation light, a development unit to form a developer image by attaching a developer to the electrostatic latent image, a voltage supply unit to supply the development unit with a development voltage, a cleaning unit to clean up the developer left on the image carrier after the development, and a developer discard amount controller to control an amount of the developer to be forcibly attached to the image carrier based on a total rotation number of the image carrier if the number of image dots printed during a prescribed number of rotations of the image carrier is smaller than a reference value, and to forcibly attach the controlled amount of the developer to the image carrier to discard the developer.

Abstract: An apparatus to form plural images on an image conveyor includes plural photoconductor bodies, a light exposure device, a development device, a transfer device, and a pattern detection device, wherein the light exposure device includes an optical scanning part, a first light detection part having a first light receiving face, a second light detection part having a second light receiving face being non-parallel to the first light receiving face, a third light detection part having a third light receiving face being non-parallel to the first light receiving face, the optical scanning part, the first light detection part, and the second light detection part being provided inside a housing of the light exposure device, the third light detection part being provided outside the housing, and a light exposure timing control device.

Abstract: A color electrophotographic image forming apparatus includes a supporting member that supports a plurality of electrophotographic photosensitive drums and is movable between an image forming position and a retracted position, a driving unit for driving the electrophotographic photosensitive drums, an intermediary transfer belt onto which images formed by developing the electrostatic latent images formed on the electrophotographic photosensitive drums are transferred, and a controller for controlling execution of image formation. The controller controls the image formation so as to provide, on the electrophotographic photosensitive drums, areas having a lowered absolute value of surface potential, and so as to stop driving of the electrophotographic photosensitive drums by the driving unit in a state that the areas are opposed to the intermediary transfer belt.

Abstract: In an image forming apparatus when a transfer material is fed at a first speed, a moving speed of an image bearing member, an exposure speed of an exposure device in a moving direction of the image bearing member, and a moving speed of an intermediary transfer member are equal to the first speed. When the transfer material is fed at a second speed which is lower than the first speed, the moving speed of the image bearing member is equal to the first speed, and the exposure speed of the exposure device and the moving speed of the intermediary transfer member are equal to the second speed.

Abstract: An image forming apparatus includes a reading unit reading an original document and generating image data; a power source unit supplying power to the reading unit; a power source switching signal output unit outputting a switching signal for switching between supply and shut-off of the power for any one of an image pickup element and an image processing unit; a measuring unit measuring a power stopping time while the power is shut off; a judging unit determining whether to carry out only a first initial setting when the measured power stopping time is less than a predetermined time and whether to carry out both the first initial setting and a second initial setting when the measured power stopping time is the predetermined time or more; and an initial setting unit carrying out only the first initial setting or the second initial setting also upon the determination by the judging unit.

Abstract: A length L of the test pattern string is determined so as to satisfy a condition L?{P?(Q1+Q2)}×V, where a time Q is a total time of a time Q1 for which the test pattern string is transferred from an exposure position of the test pattern string to a sensor and a time Q2 from when the test pattern is detected by the sensor until a color misregistration correction value calculated on the basis of a result of detecting is reflected in image formation; a time P is a time from a timing of starting to write the test pattern string to a timing of starting to write an image in which the correction value should be reflected; and a driving speed of a second image carrier is V.

Abstract: A method of measuring a total amount of latent image charge includes: scanning a sample with a charged particle beam, the sample having a charge distribution on a surface of the sample, the charge distribution being caused by forming an electrostatic latent image by exposure; measuring a state of a surface charge distribution on the sample based on a detection signal obtained by the scanning; obtaining an electric potential at a potential saddle point, the potential saddle point being formed by the surface charge distribution of the sample; obtaining an electrostatic latent image area, the electrostatic latent image being formed by the surface charge distribution of the sample; and performing a calculation using the electric potential at the potential saddle point and the electrostatic latent image area to measure a total amount of electric charge of the electrostatic latent image.