Abstract: The exemplary embodiments are directed to a control system and method of predicting how a machine will respond to occasional or periodic maintenance or service, and adjusting the machine accordingly to account for the change in machine behavior due to the maintenance or service action. More specifically, in a machine under closed-loop control subject to occasional maintenance or service, the maintenance or service results in transient in machine performance. To mitigate transients in machine performance due to maintenance or service, a prediction of the maintenance or service effect is fed forward the existing control system just prior to the occurrence of maintenance or service in order to compensate for the maintenance or service effect. This prediction is continually updated and refined using subsequent measurements of the effect of maintenance or service on machine performance.

Abstract: A color image forming apparatus includes a developing unit to which a developing bias with an AC component superposed is applied, wherein the DC voltage of the developing bias is adjusted to set the detected density of a solid image at a specified value, the light amount of radiation for exposing an image area having a width of a few dots adjacent to the white paper is adjusted to set the detected density of an image developed under a peripheral electric field at a specified value, and the gradation density curve is regulated by alternately adjusting the DC voltage, the light amount of radiation for exposing the image area having a width of a few dots adjacent to the white paper, and the amplitude of the AC component until the detected density of a mesh point image having an area ratio from 60 to 80% falls within a specified range.

Abstract: A color image forming apparatus includes a plurality of image carriers for at least one color, a plurality of developing devices, each developing a toner image onto each image carrier, a plurality of charging devices, each charging the each image carrier, a first power source, connected to the developing devices in common, a second power source, connected to the charging devices in common, and a controller, changing a process control of at least one of the charging devices and the developing devices in accordance with a color image forming operation and a monochrome image forming operation.

Abstract: A developing device having a developing gap detecting function includes a photosensitive medium, a developer conveyer, a DC power source, an AC power source, a current detecting unit and a controller. The current detecting unit detects a DC current flowing on the developer conveyer when toner from the developer conveyer is attached to a desired area of an electrostatic latent image on a photosensitive body by enhancing a voltage outputted from a power supply gradually at proper intervals. The controller obtains a developing gap between the photosensitive medium and the developer conveyer based on current values detected by the current detecting unit. In accordance with the developing device having the developing gap detecting function, the developing gap is sensed and developing voltage is easily and correctly calculated to control image forming conditions. As a result, an image quality improves.

Abstract: An image forming apparatus decreases the speed of moving an optional position in the circumference of a photoconductor, the speed of moving the surface of a transfer belt, and the speed of moving an optional position in the circumference of a roller body of a fixing unit, in a period from a moment when a part of the surface of a transfer belt corresponding to the rear end of the last one of a plurality of overlaid toner images passes a primary transfer position, to a moment when a part of the surface of a transfer belt corresponding to the front end of a toner image held in the transfer belt in the overlaid state reaches the primary transfer position.

Abstract: A photosensor apparatus includes a light receiving element that receives reflection light of light which is illuminated onto a reference pattern image formed on a moving member, a first illuminating unit that enters regular reflection light to the light receiving element, a second illuminating unit that enters diffuse reflection light to the light receiving element, and a light receiving optical system that conducts the regular reflection light and the diffuse reflection light to the light receiving element. Preferably, the light receiving optical system includes a lens, constitutes an image forming optical system that forms the reference pattern image on a light receiving plane of the light receiving element with respect to the diffuse reflection light, and enters to the light receiving plane of the light receiving element only a part of regular reflection light, which is reflected from substantially the same region where the diffuse reflection light is received.

Abstract: There is provided an image forming apparatus which is capable of securing a time period for measuring the base reflected light quantity required for the base correction, and at the same time, reducing a time period required for the entire image density control. An image forming unit includes an image carrier disposed to be exposed to light to have a latent image formed thereon, an electrostatic charger that charges the image carrier to a predetermined polarity, a developing device that visualizes the latent image formed on the image carrier to form a visible image, and an endless belt onto which the visible image is transferred. A CPU controls the image forming unit to form predetermined detection patterns on the endless belt. The detection patterns and the quantity of reflection light from the endless belt are detected. The CPU corrects the detected detection patterns based on the detected quantity of reflection light.

Abstract: An image processing apparatus is capable of determining the optimal fixing condition taking the local toner distribution (toner density) into consideration from image data. The toner amount is obtained for a local area formed by a marked pixel and the surrounding pixels per color component signal, and the toner amount of each local area is added. Further, over the image data entirely, the toner amount of local area is worked out in plural local areas. Then, a toner amount that indicates the maximum value is acquired from the toner amount of plural local areas. On the bases of the toner amount in the local area that indicates the maximum value and the kind of sheet on which toner is fixed, the fixing speed is controlled optimally.

Abstract: An image forming apparatus includes, a first speed decision unit which decides the driving speed of a drive source of a unit for printing, a magnification adjustment unit which adjusts the magnification of image information by changing the speed of the first speed decision unit, a second speed decision unit which decides the driving speed of a drive source of a carry unit to carry a printing medium, and a speed change interlock unit which changes the speed of the second speed decision unit, when the speed of the first speed decision unit is changed by the magnification adjustment unit.

Abstract: An image forming apparatus including a photosensitive member that holds an image formed by a developing agent, a charging device that charges a surface of the photosensitive member, a voltage applying device that applies a voltage to the charging device, a first cleaning element that contacts the surface of the photosensitive member, a second cleaning element that contacts a surface of the first cleaning member, and a first voltage controlling device, connected to the charging device, the first cleaning element and the second cleaning element, that generates a predetermined potential difference between the first cleaning element and the second cleaning element based on the voltage applied to the charging device.

Abstract: A real-time photo-induced discharge curve (PIDC) model generator uses a nonliner model structure based on the physics of a xerographic system photoreceptor. The PIDC generator estimates a small number of parameters in the PIDC model in real-time for a given xerographic system configuration. The estimated PIDC may be used by xerographic system process controls, diagnostics and xerographic system setup in real-time.

Abstract: An image forming method includes the steps of: forming a plurality of electrostatic latent images of a non-solid control patch by converting a reference input density; detecting a patch potential of each of the plurality of electrostatic latent images; calculating a density value of image data corresponding to a desired patch potential from the detected plurality of patch potentials; detecting a density of each of the plurality of non-solid control patches which has been formed by an imagewise exposure according to the image data of the reference input density obtained by the calculating step; forming an image by controlling an image forming condition in accordance with a detected density signal.

Abstract: A method for generating a calibration product for an image producing device. The image producing device includes a plurality of toner stations and a transfer medium. Each toner station is configured to deposit an associated toner onto the transfer medium to thereby generate the calibration product. The method includes depositing a first toner from a first toner station onto the transfer medium while moving the transfer medium from a first position relative to the plurality of toner stations to a second position. The method further includes depositing a second toner from a second toner station onto the transfer medium while continuing to deposit the first toner onto the transfer medium while moving the transfer medium from the second position to a third position.

Abstract: A quadruple-tandem type image forming apparatus in which four units of an image forming unit are disposed, and toner images are transferred to a transfer material sequentially, wherein supposing that surface potentials of a photosensitive body in each image forming unit are V0a, V0b, V0c, V0d from upstream in a moving direction of a transfer material toward downstream, development bias voltages in each image forming unit are VBa, VBb, VBc, VBd, and electrification quantities of a toner in each developing unit in each image forming unit are qa. qb, qc, qd, the relations of V0a≧V0b≧V0c≧V0d, VBa≧VBb≧VBc≧VBd, and qa≧qb≧qc≧qd (wherein V0a>V0d, VBa>VBd, qa>qd) are fulfilled.

Abstract: A method of compensating for image quality controls a toner reproduction curve (TRC). The toner reproduction curve TRC &PHgr;(k) measured by a color toner density sensor is compared with a target TRC &PHgr;R to obtain a deviation &Dgr;&PHgr;. A variation &Dgr;VB of a developer bias VB is calculated from a Jacobian matrix (JB) of a measured developer bias VB to calculate a new developer bias VBN and determining a measured grid voltage VG as a new grid voltage VGN if the deviation (&Dgr;&PHgr;) is greater than a tolerance &Dgr;&PHgr;T. A backplating vector VBP is obtained from the grid voltage VGN and the developer bias VBN. The backplating vector VBP is compared with a critical value VT to set control parameters VGN and VBN and control the TRC &PHgr;. Thus, noise effects on the image quality are minimized to provide an output image closest to an input image quality so as to improve the image quality.

Abstract: An image forming apparatus including a photosensitive member that holds an image formed by a developing agent, a charging device that charges a surface of the photosensitive member, a voltage applying device that applies a voltage to the charging device, a first cleaning element that contacts the surface of the photosensitive member, a second cleaning element that contacts a surface of the first cleaning member, and a first voltage controlling device, connected to the charging device, the first cleaning element and the second cleaning element, that generates a predetermined potential difference between the first cleaning element and the second cleaning element based on the voltage applied to the charging device.

Abstract: The present invention employs a thickness detecting mechanism including a system for emitting polarized light and a reception system for receiving reflected light and generating electric signals. By use of this thickness detecting mechanism, the thickness of a toner layer attached to a latent image is measured. Developing conditions are controlled in relation to the measured thickness.

Abstract: In a method for forming an image, an electrification device electrifies an image bearing member to a predetermined potential. An exposure device exposes the electrified image bearing member. A potential detection device detects the potential of the electrified image bearing member and the image bearing member is re-electrified using the electrification device in accordance with a value obtained on the basis of the detected potential. The potential of the re-electrified image bearing member is detected. A value to be applied to the electrification device is determined on the basis of both the detected potential and the redetected potential when a difference between the redetected potential and a target value is great. An image is formed by electrifying the image bearing member in accordance with the determined value.

Abstract: A method of calibrating a multi-color electrophotographic machine having an image bearing surface includes forming toner patches of cyan, magenta, and yellow solid areas individually and in superimposed combination to form a series of single layer and multi-layer test patches. Light is emitted onto these single and multi-layer test patches. The amount of light that is reflected off of each test patch is measured. Light is also emitted onto a bare section of the image-bearing surface. The bare section has substantially no toner thereon. An amount of light that is reflected off of the bare section is measured. The step of measuring an amount of light reflected off single layer solid area test patches is repeated for a series of laser power and developer bias conditions. A laser power and/or a developer bias is adjusted dependent upon each of the three measuring steps.

Abstract: An image forming apparatus includes an image bearing member for bearing a latent image and a charger for charging the image bearing member. The charged image bearing member is exposed to form the latent image and a developing unit develops the latent image. One of an exposure amount reduction mode for executing image formation by reducing an exposure amount and a normal mode for executing image formation with a normal exposure amount is selected. A correction amount of a look-up table for gradational correction is changed when the exposure amount reduction mode is selected.

Abstract: An adjustment control system compares multiple control amounts detected by a sensor with target values, thereby computing individual control amount deviations. When at least one of the control amount deviations is out of a predetermined tolerance, an operation-amount-determining section determines operation amounts for compensating the control amount deviations. When successful instances that have been used in the computed control amount deviations are available, the operation-amount-determining section executes a learning-control method that determines the operation amounts according to the control instances. When the successful instances are not available, the operation-amount-determining section executes an adaptive-control method and thereby determines the operation amounts.

Abstract: An image forming apparatus has an image forming device for forming an image on a recording material, a storing device for storing a parameter regarding an accumulation operation amount of the image forming apparatus, and a changing device for changing an image forming condition of the image forming device in accordance with the parameter.

Abstract: There is disclosed an image forming apparatus in which photosensitive member properties including potential properties of an exposed portion and unexposed portion of the surface of a photosensitive member irradiated with a light beam are estimated. An appropriate contrast potential and a developing bias voltage and charging grid bias voltage suitable for forming a high-density image are determined by a feedback control based on the photosensitive member properties. A laser power is changed to form an intermediate-density image whose density agrees with an intermediate-density target value. When the laser power is changed, the photosensitive member property changes. Therefore, the photosensitive member property is re-estimated, and the developing bias voltage and charging grid bias voltage are set again while maintaining the appropriate contrast potential.

Abstract: An image forming apparatus including a photoconductive member, a charging mechanism, an optical writing mechanism, a development mechanism, a sensing mechanism, and a controlling mechanism. The charging mechanism charges a surface of the photoconductive member at a charge voltage. The optical writing mechanism writes latent images including first and second latent images on the surface of the photoconductive member. The development mechanism develops the first latent image into a first toner pattern at a solid toner density and the second latent image into a second toner pattern at a half-tone tone density. The sensing mechanism detects reflection densities of the first and second toner patterns and generates output signals representing detection results detected by the sensing mechanism. The controlling mechanism adjusts values of the solid toner density, the charge voltage, and the half-tone toner density based on the output signals.

Abstract: A first embodiment of a measurement system provides an indication of performance of an electrophotographic process. The first embodiment includes a charge measurement device coupled to a developing device and a high voltage power supply. The charge measurement device generates a signal corresponding to the net charge transferred between the high voltage power supply and the developing device during an imaging operation. The measured charge transfer is compared to an estimated charge transfer to determine if the electrophotographic process is operating correctly. The estimated charge transfer is determined by multiplying an estimate of the mass of the toner transferred during an imaging operation by an average value of toner charge to mass ratio. A sufficiently large difference in the magnitude between the measured charge transfer and the estimated charge transferred indicates that the electrophotographic process is not operating correctly.

Abstract: An engine controller adjusts an image density of the toner image to a target density by controlling an electrifying bias and a development bias. The engine controller determines an optimal development bias which is needed to obtain the target density based on densities of first patch images which are formed in the following bias condition: The electrifying bias is fixed at the most recent optimal electrifying bias which is stored in a RAM; and the development bias is gradually changing based on the most recent optimal development bias which is stored in the RAM.

Abstract: An image-forming apparatus for forming an image by electrically charging a photosensitive material, forming an electrostatic image through the exposure to light and developing the electrostatic image, wherein the main charged potential, Vo, of the photosensitive material, the potential, Vr, of the exposed portion of the photosensitive material and the developing bias potential DB are so set as to satisfy the following formulas, V1≦|DB−Vr|≦V2  (1) V3≦|Vo−DB|≦300  (2). V1, V2 and V3 are parameters calculated from a developing characteristics curve obtained by plotting the image densities to a potential difference between the developing bias potential and the surface potential, 0 V, of the photosensitive material when the image is formed by changing the developing bias potential with the exposure amount being zero in a state where the potential on the surface of the photosensitive material is maintained at zero.

Abstract: Disclosed is a toner image fixing device that is capable of changeably setting sheet separating portions in contact with or apart from the cylindrical surfaces of corresponding fixing rollers in accord with the resiliency of recording material to surely prevent a recording material from wrapping round the fixing rollers and being jammed between the rollers and capable of minimizing the frequency of contacting the separating portions with the fixing roller surfaces to obtain an increased quality of a toner image fixed on the recording material and elongate the service life of the fixing rollers.

Abstract: An image forming device, in accordance with the present invention, stores the correction factors produced during calibration cycles for future analysis. The correction factors, or alternatively, the new printer control parameters, which incorporate the correction factors, may be adjusted for current environmental conditions. During the calibration cycle, the correction factors produced during the current calibration cycle and old correction factors produced during prior calibration cycles are analyzed to determine if the printer control parameters are within desired degradation limits, which indicate that the print quality of the imaging forming device will degrade beyond acceptable limits prior to the next calibration cycle. Thus, a statistical analysis of the historical data produced during calibration cycles can be used to predict when the image quality of the image printing device will degrade beyond acceptable limits.

Abstract: An electrophotographic printing method and apparatus in which a charge voltage is appropriately adjusted depending on the resolution selected for electrophotographic printing or the print mode are provided. The electrophotographic printing method and electrophotographic imaging apparatus provide for selecting a resolution for electrophotographic printing; charging an organic photoconductor (OPC) by applying to a charge roller an appropriate charge voltage depending on the selected resolution; forming an electrostatic latent image on the charged OPC by a laser scanning unit (LSU) and applying toner particles adhering to a developer roller to the electrostatic latent image to form a visible image; and transferring the visible image formed on the OPC to a sheet of print paper. By selecting the print resolution or print mode, the charge voltage can be adjusted depending on the print resolution or print mode, so that an image can be obtained with reduced image concentration variation.

Abstract: An electrophotographic apparatus has a detector, for detecting a surface potential on the photosensitive member, a determination unit, for employing the detection results obtained by the detector to determine an electrification amount for the electrification unit and an exposure control value for the exposure unit, for determining the electrification amount for the electrification unit, so that a dark portion potential on the photosensitive member is substantially a target dark portion potential selected from multiple target dark portion potentials, for determining a first exposure control value for the exposure unit, so that a light portion potential, which is based on the determined electrification amount and which is formed on the photosensitive member by the electrification unit and the exposure unit, is substantially a first target light portion potential, and for determining, in accordance with the first exposure control value and the selected target dark portion potential, a second exposure control val

Abstract: An image forming apparatus is provided with a function for forming an image on a recording medium such, as a sheet or the like. The image forming apparatus includes an image forming unit for forming an image on a recording material including an image bearing member. A developing unit develops an electrostatic image formed on the image bearing member by a developer. A density detection unit detects a developer density inside the developing unit. The density detection unit detects a parameter relating to physical property of the developer based on a previous detection value detected by the density detection unit during a previous image forming drive operation by the image forming unit and before the previous image forming drive operation stops. The detection unit also detects a next detection value detected by the density detecting unit after the previous image forming drive operation stops and before a next image forming drive operation by the image forming unit starts.

Abstract: An image-forming apparatus for forming an image by electrically charging a photosensitive material, forming an electrostatic image through the exposure to light and developing the electrostatic image, wherein the main charged potential (Vo) of the photosensitive material, the potential (Vr) of the exposed portion of the photosensitive material and the developing bias potential DB are so set as to satisfy the following formulas (1) and (2),

Abstract: An image forming apparatus includes an LED array for performing exposure according to an input image signal, a photoconductive drum on which an electrostatic latent image is formed by exposure with the LED array, a developing device for making the electrostatic image visible, a transfer charger for transferring the visible image onto a transfer material, and a fixing device for fixing the image on the transfer material. When the operating speed in an image forming process equals the image forming speed, and the image forming speed can be switched among a plurality of levels, the image forming condition is changed in accordance with the image forming speed.

Abstract: An electrophotographic apparatus comprises: a photosensitive member; an electrostatic image forming unit, for forming an electrostatic image on the photosensitive member, including electrification means for electrifying the photosensitive member and an exposure unit for exposing the photosensitive member; a detector, for detecting a surface potential on the photosensitive member; a determination unit, for employing the detection results obtained by the detector to determine an electrification amount for the electrification unit and an exposure control value for the exposure unit, for determining the electrification amount for the electrification unit, so that a dark portion potential on the photosensitive member is substantially a target dark portion potential selected from multiple target dark portion potentials, for determining a first exposure control value for the exposure unit, so that a light portion potential, which is based on the determined electrification amount and which is formed on the photosensi

Abstract: An image processing apparatus capable of color image formation with a plurality of color components, which solves a problem of increment of processing time in monochrome image formation due to correction on image formation conditions with predetermined patch formation. For this purpose, in case of monochrome image formation, even if a tonality control request flag is set, an image formation sequence is started without performing tonality control. Thus processing time can be reduced in monochrome image formation.

Abstract: In an electrostatic and development control in a printing apparatus, unwanted variation in dot size and shape may be stabilized and the DMA variability under halftone control may be decreased, by use of a novel halftone discharge ratio (HTDRmidtone) along with the conventional actuators of development potential, cleaning potential, and exposure level. A three-input, three-output MIMO control system may be constructed to deliver superior regulation of halftone and solid area image quality with use of control algorithms that are based on the halftone discharge ratio and with use of as few as two developed halftone test patches.

Abstract: An image forming apparatus comprises:

Abstract: A printer or copier apparatus is fashioned in such a way that with a single apparatus a recording medium can be printed both with magnetically readable toner (MICR toner) and also with standard toner. For this purpose, it contains one or more correspondingly fashioned developer stations (ES) and a control unit for the adaptation of the print process parameters dependent on the mode of operation.

Abstract: Bidirectional communication is carried out between a toner bottle end communication device disposed in a toner bottle and a main body end communication device disposed in a device main body while the toner bottle is moved from a first position where the toner bottle starts being attached to the device main body to a second position where the toner bottle is completely attached. The CPU provided in the main body end communication device decides whether or not the information on the toner bottle received from the toner bottle end communication device matches the device main body, and notifies prior to toner refilling. If the toner bottle is not suitable, the CPU specifies a lower quality image forming condition under which operation conditions for the main charging device, exposure device, and fixing device are changed so as to produce an image of relatively low quality in comparison to normal quality.

Abstract: The present invention relates to an electrophotographic apparatus in which the apparatus is provided with a sequence in which a dark portion and a light portion are formed on a first portion and a second portion, respectively, on a photosensitive member by an electrostatic image forming device, whereafter the first portion and the second portion are exposed by a pre-exposure device, and then the first portion and the second portion are charged by a charger, and then a surface potential of the first portion and the second portion are detected by a detector, and an exposure amount at which the photosensitive member is exposed by the pre-exposure device is controlled in conformity with the potential of the first portion and the potential of the second portion detected by the detector in the sequence.

Abstract: A control system for a xerographic printer utilizing hybrid scavengeless development in the marking process which selectively adjusts process parameters for closed loop feedback control to maintain a preselected tone reproduction curve. The curve is selected to enhance the effectiveness of the range of distinguishable densities in a printing device. The system monitors a series of control patches of varying area coverage density and compares the representative values from the sensor patches with preselected target values. When the measured value significantly departs from the target value, control steps are implemented to affect the toner powder cloud height in the development zone to either add or decrease the mass of toner powder deposited on the photoreceptor.

Abstract: An online printing parameter establishment apparatus is used with a xerographic printing device for printing high quality prints given a target value. The xerographic printing device is capable of producing at least one print control patch on a photoreceptor and is capable of sensing a value of the at least one print control patch. The xerographic printing device has a plurality of sets of inherent performance characteristic values. The online printing parameter establishment apparatus includes a controller device and a switch device. The controller device is operative to produce a first database of different ones of the sensed values. Each sensed value is associated with a respective one of the plurality of sets of inherent performance characteristic values based upon the target value. The controller device is also operative to produce a second database of a plurality of control values.

Abstract: An image forming apparatus includes an image bearing member; a charging member for charging a surface of the image bearing member while contacting thereto with a predetermined voltage applied to the charging member; exposure member for exposing the surface of the image bearing member to form an electrostatic latent image; a toner carrying member contacted to the image bearing member with a predetermined voltage applied to the toner carrying member to visualize the electrostatic latent image into a toner image with toner carried thereon; an image transfer member for urging a transfer material to contact the transfer material to the image bearing member with a predetermined voltage applied to the image transfer member to transfer the toner image onto the transfer material; a device for applying the predetermined voltages to the charging member, the toner carrying member and the transfer member; and a controller for controlling the device that applies the predetermined voltage, the controller being operable in a

Abstract: A printer or copier has a photoconductor on which charge patterns are formed that are in turn inked and printed onto a recording medium. An optimized exposure energy is determined for a given potential of the photoconductor by calculating a sensitivity factor. The optimized charge potential may also be calculated on the basis of the sensitivity factor for a given exposure energy.

Abstract: An electrophotographic apparatus including a photosensitive member; a corona charger for charging a surface of the photosensitive member; a circuit-forming/chargeable powder supplying device for supplying circuit-forming/chargeable powder to a latent image pattern on the photosensitive member; a transferring device for transferring the circuit-forming/chargeable powder on the latent image pattern onto a ceramic green sheet; a flash lamp for fixing the circuit-forming/chargeable powder, transferred onto the ceramic green sheet, in order to form a circuit pattern (not shown) on the ceramic green sheet; and a circuit pattern forming position recognizing camera for detecting a circuit pattern forming position on the ceramic green sheet. In the electrophotographic apparatus, laser beams are used to form a predetermined latent image pattern (not shown) on a surface of the photosensitive member.

Abstract: An image forming apparatus capable of preventing unnecessary adhesion of a developer to an uncharged region of a latent image carrier. The image forming apparatus includes an endless latent image carrier, a charging unit for charging the latent image carrier, a latent image forming unit for forming a latent image on the latent image carrier charged, a developing unit for developing the latent image formed on the latent image carrier with a developer by supplying the developer to the latent image carrier under application of a developing bias voltage, and a transfer unit for transferring the image developed on the latent image carrier to a sheet.

Abstract: A color image forming apparatus includes a carrier belt which runs along a transport path of a recording medium to transport the recording medium. A number of image-forming sections are aligned in the transport path. Each of the plurality of image-forming sections forms a toner image of a corresponding color included in an image signal. A plurality of transfer units are provided, with each being disposed to oppose a corresponding one of the number of image-forming sections. Each of the number of transfer units transferring the toner image of the corresponding color to the recording medium. A fixing unit is provided that fixes the toner image to the recording medium. A controller is provided that detects a number of colors in the image signal. The controller sets one set of speeds from a plurality of different sets of speeds in accordance with the number of colors.

Abstract: An electrophotographic device and a density control method are disclosed. In the apparatus such as a color laser beam printer and a copier using an electrophotographic developing method, the invention obtains an optimum print output regardless of the remaining toner or other contamination by locating a density control module inside of a transfer body, and by providing a transparent window in a dielectric sheet formed on the exterior surface of the transfer body.

Abstract: An image forming apparatus has a photosensitive drum on which toner images of different colors are formed and sequentially transferred in layers to an intermediate transfer drum. In the continuous color image formation, depending on whether to be the first page or after second page, for example, the control of the correcting system for color mis-registration is switched so that the mechanical effect on the apparatus caused by biasing and unbiasing actions of a transfer roller and an ICL roller toward the intermediate transfer drum in each condition can be suppressed to the minimum without penalties in throughput.