Abstract: In an image forming apparatus for electrophotographically forming an image with an LED (Light Emitting Diode) array having a number of LEDs arranged in an array for controllably emitting light in accordance with image data, dots to be respectively formed by the LEDs have a target dot diameter X satisfying a relation of P<X<2P where P is a pitch P between the LEDs. Despite that the dot diameters of LEDs may slightly differ from each other, an image free from noticeable white stripes or black stripes is achievable although some difference in density may occur, depending on the overlapping degree of or the distance between dots.

Abstract: In an image forming apparatus which represents gradation of an image by using a halftone screen structure, and which transfers and fixes the image onto a print sheet by using an intermediate transfer body, where a number of protruding portions are provided with an approximately uniform distribution, the degradation of image quality due to a moire fringe pattern produced by the halftone screen structure and the distribution of the protruding portions of the intermediate transfer body is reduced.

Abstract: A visual control strip for imageable media such as a printing plate, a photographic film or a printable substrate is described wherein the visual control strip is to be applied to the imageable medium. The control strip includes a plurality of first control fields having differing grey tone values which are relatively insensitive to the processing variables which influence the size of the spots or dots produced on the imaged medium. The control strip also includes at least one second control field which is relatively sensitive to these process variables. The second control field is located immediately adjacent to the first insensitive control fields for ease of comparison. The second sensitive control field has a target grey tone value which may typically be 25%, 50% or 75%. To improve assessment of exposure parameters, the insensitive fields are completely surrounded by a sensitive field or vice versa.

Abstract: A printer includes a photosensitive drum which is exposed by a line head which includes a fluorescent head having a large number of light points which are aligned in a direction of a width of the photosensitive drum, and the respective light points of the fluorescent head are driven by a line driver in accordance with drive data from a shift register which holds the drive data for all the light points. One print line is formed by a set of four sublines. In a case where the thinning of a line width is corrected in a main scanning direction, the print line is formed by sublines more than five, whereby the line width is fatted.

Abstract: An image forming apparatus converts image data with recording density of 600 dpi which have been created in a host computer so that recording density in a vertical scanning direction is 300 dpi and recording density in a horizontal scanning direction is 1200 dpi, and outputs the converted image data to an optical system of a printer engine synchronizing with a clock frequency which is four times a normal clock frequency so as to form an image. As a result, the recording density in the horizontal scanning direction is not converted so as to be equal to the recording density in the vertical scanning direction in a conventional way, but is converted so as to have higher resolution. Therefore, an image with more improved printing quality than a conventional one can be formed by using a laser printer which can be arranged at a comparatively low price.

Abstract: An image forming apparatus converts image data with recording density of 600 dpi which have been created in a host computer so that recording density in a vertical scanning direction is 300 dpi and recording density in a horizontal scanning direction is 1200 dpi, and outputs the converted image data to an optical system of a printer engine synchronizing with a clock frequency which is four times a normal clock frequency so as to form an image. As a result, the recording density in the horizontal scanning direction is not converted so as to be equal to the recording density in the vertical scanning direction in a conventional way, but is converted so as to have higher resolution. Therefore, an image with more improved printing quality than a conventional one can be formed by using a laser printer which can be arranged at a comparatively low price.

Abstract: A method for achieving multiple exposure levels for IOI (IMAGE-ON-IMAGE) xerography when imaging a second color through a first toner layer previously developed on the photoreceptive member. In the example illustrated the data from the previous image paths (magenta and yellow) is analyzed. If the signal indicates that a magenta or yellow bit is present, the cyan output bit information passes to the ROS unchanged, or at full intensity. If however, the magenta and yellow are not present, a modified pattern providing an appropriate reduced exposure signal is sent to the ROS. The process of laser attenuation is blended with halftoning logic to avoid image degradation due to the attenuation.

Abstract: Compensation for the effects of duty cycle on the output level of an imaging device, and for the effects of periodically varying distance between the output of the imaging device and its target, is accomplished electronically. An exemplary apparatus includes a source of radiation (generally a laser) having an output level that varies both with an input power level and, undesirably, with the duty cycle. The radiation source is operated to produce, on the recording surface, an imagewise pattern of spots, and an adjustment facility compensates for output-level variations resulting from duty cycle--that is, from the recent pattern of laser activity.

Abstract: An image forming method and apparatus use a multi-beam light source in a way that enables changes in writing density to be quickly made. A rotating mechanism that has the multi-beam light source rotates about an optical axis of a light beam from the multi-beam light source. A driving mechanism is included for driving the rotating mechanism, and a detecting mechanism is included for detecting a rotating position of the rotating mechanism. A controller controls the driving mechanism in either a reference mode or a positioning mode of operation. In the reference mode, the rotating mechanism is rotated to first position, which is determined by the detecting mechanism. In the positioning mode, the rotating mechanism is rotated to another position relative to the first position according to the reference mode.

Abstract: A method and apparatus for processing a plurality of bits stored in a memory, where the plurality of bits represent a cumulative pattern to be printed by reproducing the stored bits in a fast scan direction. Each bit stored in memory has a state (e.g., binary 0 or 1). As an example, the method selects a first subset of the plurality of bits, wherein the first subset forms a first pattern and has a center bit. Further, the method selects a second subset of the plurality of bits, wherein the second subset forms a second pattern and has a center bit coextensive with the center bit of the first subset. Next, the method determines, based on the states of the bits of the first pattern, whether the state of the center bit should be printed in the same state as it is stored in the memory. In addition, the method determines, based on the states of the bits of the second pattern, whether the state of the center bit should be printed in the same state as it is stored in the memory.

Abstract: An electrophotographic printing device using a light source for emitting predetermined light and a photosensitive material on which an electrostatic latent image is formed by the light from the light source. The electrophotographic printing device has a memory for storing density control information on light intensity of the light source and density of an image formed on a printing medium, and a light intensity controller for controlling the light intensity of the light source based on the information in the memory. The density control information stored in the memory is determined from a relationship between the density of the image to be formed and potential of the electrostatic latent image, and a relationship between the potential of the electrostatic latent image and the light source.

Abstract: In an electrophotographic printing apparatus for printing using a three level printing method, there are provided a first color data memory and a second color data memory which memorize the pixel data of every color sent from host equipment, such as a computer connected to an electrophotographic printing apparatus, and by the use of image recognition equipment for judging whether pixel information is part of what image, exposure information with exposure equipment is determined so that the electric current flowing into electric current source and electric current source is changed. With such an arrangement, the exposure data for every color to be printed is created on the basis of the recognized result the part of a particular image that the pixel data shows, and the color image of the line-width in accordance with data sent from the host equipment to the electrophotographic printing apparatus can be actually printed by controlling the exposure beam diameter.

Abstract: An image forming apparatus stores a plurality of patterns, each pattern defines at least an irradiation energy amount and irradiation position(s), which facilitate the irradiation of a photosensitive member in accordance with image data. Irradiation of a photosensitive member effects the formation of latent images along the surface of the photosensitive member. The latent images are developed using a toner carrying member which includes a thin film developing sleeve which confronts the photosensitive member and carries toner.

Abstract: A color image forming method, including the steps of: charging a front surface of a photoreceptor; conducting image wise exposure onto the charged front surface from a rear surface of the photoreceptor so that a latent image is formed on the front surface; developing the latent image with a color toner so that a color toner image is formed on the front surface; and repeating the steps of charging, conducting image wise exposure and developing so that a multicolor toner image is formed on the front surface; in which a secondary color of the multicolor toner image, which consists of two color toner images, is formed in a manner that the two color toner images are formed by conducting the image wise exposure at a same exposure amount; and the first one of the two color toner images is formed by conducting the image wise exposure at an exposure amount which creates a potential smaller than that of already formed primary color of the multicolor toner image, which consists of single color toner image.

Abstract: This invention concerns an image processing device for adjusting the density of an image and an image reading device incorporating the image processing device and aims to enhance the repeatability of pseudo-gradient without reference to density distribution of the image. The image processing device which fulfills the purpose of compensating the gradient of image data consisting of multivalue digital signals comprises means ME1 to ME3 for storing a plurality of gradient compensation data T1 to T3 having mutually different contents of compensation, means for detecting a contrast of an image on the basis of a group of image data conforming to one image, and means for switching the contents of compensation for the image data by selecting one of the three gradient compensation data T1 to T3 in conformity with the contrast.

Abstract: An image processor includes an input device for inputting image signals, and a correcting device for correcting the image signals. A generating device generates a pulse-width modulation signal responsive to an image signal corrected by the correcting device, and a light emitting device emits light on the basis of the pulse-width modulation signal. A detecting device detects the pulse width of light emitted from the light emitting device, and a setting device sets correction conditions of the correcting device on the basis of the pulse width detected by the detecting device when a predetermined signal is supplied to the generating device.

Abstract: A laser printer includes at least three laser beams for simultaneously scanning a rotatable recording medium. The laser beams have their centers spaced uniform or non-uniform distances from each other. The centers of the laser beams are spaced predetermined distances from each other so that the print resolution may be 300, 400, 600, or 1,200 dpi depending upon the laser beams selected for use with at least two laser beams always being selected.

Abstract: A method is described to control the maximum density and the pixel profile of microdots produced by a binary or multilevel electrophotographic device. In various embodiments, from the maximum development potential. The working point of the device is established by imposing a relation between charge level, discharge level and saturation voltage level of the photosensitive element. This allows to achieve consistent output densities, irrespective of the environmental parameters, such as relative humidity and temperature.

Abstract: A high resolution continuous tone medical image printer is capable of printing a high resolution image on a plurality of different sized media. In a normal resolution mode, a medical image of m.times.n pixels is printed on a first sized media with a variable pixel clock operating at a first pixel clock rate, and in a second resolution mode where the medical image of m.times.n pixels is printed on a second sized media larger than the first sized media in either or both the line scan direction and the page scan direction, the pixel clock is operated at a pixel clock rate less than the first pixel clock rate such that m pixels are printed per line with the pixel size being larger in the line scan direction and such that lines of pixels are added so that more than n lines of pixels are printed in the page scan direction and such that the beam of light size, the scanner speed and the page scan speed are held constant no matter what sized media is being printed.

Abstract: An image can be outputted with a high sharpness without deteriorating a resolution. In order to output an image of a high picture quality while suppressing the occurrence of a moire, an exposure amount is modulated in accordance with pixel density information of the image divided into pixels of a predetermined size by an exposure amount modulating unit in a light scanning unit, thereby expressing an image dark/light state. In this case, in a highlight density region in which a pixel density is equal to or less than 1/3 of the maximum image density, the density data of two adjoining pixels is modulated by one pixel and the other pixel is not recorded. In a density region in which the image density lies within a range from 1/3 to 1/2 of the maximum image density, a part of the density data of one of the two adjoining pixels is transposed to the other pixel. In a density region in which the image density is equal to or larger than 1/2 of the maximum density, the pixel transposition is not performed.

Abstract: A contact electrostatic printing (CEP) apparatus and method provide custom color capabilities. Custom colors can be provided by combining two or more toner layers of different color. Correction of custom color toner patches can also be performed by combining toner layers. Controllable toner applicators apply toner patches in any desired size, shape or density on a support.

Abstract: A method of decreasing toner in solid area development to improve the latitude of a xerographic process in a machine having a projecting system for modulating a beam and projecting an image onto an imaging surface by specifying pixels defining solid image areas and selectively modulating the beam with regard to the specified pixels to change the state of the pixels from black to gray or partial white.

Abstract: An image forming apparatus and an image forming method in which a latent image is formed by scanning the surface of an image bearing body with a laser light blinking in accordance with pulse-width modulation based on an image signal. Output-control-wave generating device generates an output control wave having a peak for a write time of each picture element. The output control wave is turned on and off by a gate circuit with timing determined by an exposure control signal generated by exposure control device. A signal output by the gate circuit is converted by a V/I converter into a driving current wave for controlling radiation of a laser light by an exposure unit. In this way, exposure energy produced by the exposure unit can be concentrated on an exposure time duration of each picture element, allowing the amount of mutual interference among picture elements to be reduced.

Abstract: For input image data (`A`) before conversion, each pixel is converted into N (=3) parts. In this case, the three sub-pixels of data corresponding to a recording pixel (black pixel) are converted into recording sub-pixels on both sides of the three (`B`). This eliminates the density variation within a single pixel. Therefore, it is possible to reduce the dot spacing at slanted area, for example, and hence eliminate jaggies, providing a reproduced image easily recognized.

Abstract: An LED printer includes a printing control unit and an LED head. When a video signal received at the control unit has a higher resolution than the LED head, the control unit carries out the logical AND between successive bit data of the video signal to convert the video signal to a first signal. Corresponding to a line timing signal, this first signal is transferred as a head data signal to the LED head and is then printed on a basic raster scanning line. Further, the control unit also carries out the exclusive-OR between the successive bit data of the video signal so that the video signal is converted to a second signal and outputted to a line buffer. Corresponding to an additional line timing signal, the second signal is transferred as another head data signal to the LED head and is printed on an additional raster scanning line. The LED head drive energy for performing printing along the basic raster scanning line is set independently.

Abstract: Disclosed is a laser scanning unit for emitting a laser beam which scans on a surface to be scanned within a predetermined scanning range. The laser scanning unit has a laser diode, and a laser diode controller for controlling the laser diode to emit the laser beam. The laser beam has an intensity corresponding to one of a predetermined graduation steps within a intensity range defined by a first intensity and a second intensity greater than the first intensity in accordance with an image data. The laser scanning unit is further provided with a controller which is capable of shifting the intensity range by changing the first and second intensities.

Abstract: An image forming apparatus for reproducing an image corresponding to a digitized image signal includes; an imaging member; a halftone image forming device for reproducing a latent image composed of a plurality of pixels on the imaging member, and for developing the latent image so that coloring particles are adhered in each pixel being put together as an island, the halftone image including a relatively low density halftone image; and a transfixing device for simultaneously transferring the halftone image and fixing the halftone image onto a recording sheet. The image forming apparatus may further includes an intermediate transfer medium. The island-like toner image reproduces the halftone image clearly.

Abstract: A resolution enhancement apparatus and method of a laser printer using a modulated laser beam is adapted to an image forming apparatus of the laser printer, and includes a memory for storing sequentially input image data in a sequential scanning method, rearranging a scanning line order and generating an M.times.M sample window, M being an integer, a first processor for producing (M-2).sup.2 3.times.3 sample windows using the M.times.M sample window, determining which mask pattern among a plurality of mask patterns is coincident with each of the produced 3.times.

Abstract: The temperature and humidity around a photoreceptor drum and the total number of copied sheets of the photoreceptor drum are detected. Data LDATA for setting the intensity of a laser beam and data BDATA for setting the beam diameter according to the detected results are provided from an image control circuit to a laser drive circuit and a collimator lens drive circuit. The laser drive circuit corrects the intensity of the laser beam output from an LD package according to LDATA, and the collimator lens drive circuit controls the position of the collimator lens according to BDATA to correct the beam diameter of the laser beam.

Abstract: In a digital full color copying machine, one pixel on a photoconductor is divided into four subdivided small pixels. Functions a-d are assigned to each subdivided small pixel. Functions a-d are linear functions with density data as a parameter. The slope of functions a-d becomes smaller in sequential order. Exposure data of the four subdivided small pixels is calculated according to the density data of a pixel and functions a-d to expose each subdivided small pixel. A peak can be established in the exposure amount distribution to form a deeper latent image. Accordingly, resolution and graininess of the halftone area are improved.

Abstract: An electrostatographic reproduction method and apparatus includes an electrostatic recording member moving in a process direction. A plurality of recording elements on a writer imagewise expose the recording member to form electrostatic latent images on the recording member. The writer includes driver circuitry for actuating selected recording elements. The exposed recording member is then moved through a development station to develop the latent images. The developed images are transferred to a record member. An operator selectable adjustment controller is manually adjusted for generating adjustments in operation of the recording elements to compensate for a misalignment of a process station in the apparatus.

Abstract: An electrophotographic image forming apparatus has a photosensitive drum; a charging device for charging a surface of the photosensitive drum; an LED array for projecting a light beam on the surface of the photosensitive drum, thereby forming irradiated spots constituting an electrostatic latent image. The irradiated spots are formed on intersections of a grid which is composed of a plurality of first lines extending in a main-scanning direction and arranged at equal first intervals and a plurality of second lines extending in a sub-scanning direction and arranged at equal second intervals. The apparatus also has a developing device for attaching a toner particle extending to each of the irradiated spots, a transfer device for transferring the toner particle to a transfer material, and a fixing device for fixing the toner particle on the transfer material.

Abstract: An apparatus for developing an electrostatic latent image in a liquid developing material-based electrostatographic printing machine including a control system for controlling an amount of marking particles, carrier liquid and/or charge director added to a supply of liquid developing material utilized for developing a latent electrostatic image such that the concentration of marking particles and or charge director can be maintained at an optimal value. The amount of marking particles, carrier liquid and/or charge director in a supply of liquid developing material is maintained at a predetermined optimal value in response to the amount of marking particles and/or charge director depleted from the supply of liquid developing material with each development cycle. A supply reservoir is maintained with a substantially constant amount of liquid carrier to which is added marking particles and/or charge director to provide an operative solution of liquid developing material.

Abstract: An optical writing device by which an image with desired tone can be obtained. The optical writing device includes a write head and a modulation unit. A time for scanning of one picture element is divided into some periods by the modulation unit. The modulation unit judges whether the picture element will be in an imaged region or in a blank region and whether the picture element must be provided with a supplementary exposure value. The picture element will be provided with an accumulated exposure value corresponding to a desired level of tone by being provided with the supplementary exposure value by order of the modulation unit.

Abstract: An image forming apparatus includes an exposure unit forming a latent image using a light from a light source, a developing unit forming a toner image by visualizing the latent image using a toner, a detector outputting a detection signal by optically detecting an amount of toner of the toner image, a memory storing an optimum value of the detection signal output from the detector with respect to a light emission time of the light source, with respect to a plurality of light emission times of the light source to thereby store a plurality optimum values, and a control unit controlling the light emission time of the light source by calculating a light emission time corresponding to a value of the detection signal output from the detector based on the plurality of light emission times stored in the memory.

Abstract: A method for generating a screened reproduction of a multiple tone image comprises the steps of autotypical or amplitude modulation screening the multiple tone image to obtain screened data representing tones of the multiple tone image in terms of halftone dots; reproducing the halftone dots on an imaging element by means of a scan-wise exposure by means of a laser or a LED, wherein in extreme regions of the tone scale the shape of the halftone dots is compact, characterized in that the halftone dots have a ratio of peripheral length to surface area which is minimal.

Abstract: An improved method for estimating toner usage in digital xerographic printers and copiers. The method is characterized by taking into account digital image dot spreading which results in the area of a pixel not being developed fully and some areas outside of the pixel being developed. Thus, the improved method takes into account the departure of a developed image from an ideal shape (i.e. square). To this end, the improved method compensates for departure of a developed image from an ideal shape. In carrying out the method estimated toner usage is based on pixel groupings rather than simple pixel counting.

Abstract: A method of adjusting imaging apparatus including: (a) charging a photoreceptor surface to a first voltage; (b) selectively discharging portions of the charged photoreceptor surface, with a beam of electromagnetic energy such as a laser beam or LED output, having a controllable power, to form a predefined electrostatic latent test image on the photoreceptor surface; (c) developing, using a second voltage different from the first voltage, a layer of charged toner particles onto the selectively discharged portions of the photoreceptor surface, thereby providing a developed test image corresponding to the latent test image; (d) measuring the apparent optical density of portions of the developed test image, including a solid print portion and a predetermined gray level portion; (e) comparing the measured solid and gray level optical densities with predetermined, desired, solid and gray level optical densities; and (f) adjusting the second voltage and the power of the laser beam based on the comparison between the

Abstract: Method and apparatus for forming halftone images which enables image recording on a process film without reducing the size of the recording area beyond that which is necessary. The method and apparatus is preferred particularly in the preparation of a master printing plate such as a printing plate which includes a photosensitive member having an organic silver salt. According to the method and apparatus, an image recording apparatus propagates error data when there exists a restriction on the minimum recording size and thereby preserves halftone concentration and reproduces intermediate gradation of darkness with stability.

Abstract: A pixel matrix preferably containing nine pixels is analyzed to determine whether or not all of the image values for the pixels in the pixel matrix correspond to a full saturation level. If the image values do correspond to full saturation level, preferably the center pixel is produced using a variably reduced toner output. If all of the image values do not correspond to full saturation level, the center pixel is produced using conventional methods. The system of the preferred embodiment is comprised of an input buffer for storing the image values, a comparator for comparing the image values with a toner modification value to determine if the pixel or pixels should be produced using a variably reduced toner output. The pixels are then preferably stored temporarily in an output buffer and then sent to a memory to be produced.

Abstract: A halftoning method characterized by two nonaligned halftone screens, one for black and the other for the subtractive primary colors cyan, magenta, and yellow, produces multi-color images on a color laser printer. The black screen is the inverse of, i.e., in reverse fill order to, the subtractive primary colors screen. The halftone pattern is a vertical line screen. In a preferred embodiment, the cells are grouped on hexagonal centers and aligned along X and Y coordinate axes. The dots are grouped in the linear direction of print medium motion. The grouping of dots reduces the effect of halftone screen misregistration, and the cell alignment in X and Y results in fewer high frequency artifacts. Inverting the black screen increases the number of possible chromatic mixed colors that include black, increases color uniformity and reduces the frequency of white "holes" in the printed images.

Abstract: A method of reducing the effects of aliasing. Pixels are divided into phases, such that a phase or combination of phases may be printed to provide one of a number of dot shapes for each pixel. When a pixel is partly overlapped by an object to be printed, that pixel's dot shape is determined by determining which dot shape is the best geometrical match with the overlap. (FIGS. 3 and 7). Then, a greyscale value is determined for the selected dot shape by determining what greyscale will provide an effective greyscale that substantially corresponds to the percent of overlap by the object with the pixel. An alternative method selects a greyscale value for each phase rather than for the entire dot shape.

Abstract: A picture forming apparatus comprises a memory means for storing an inputted picture data, a picture data changing means for changing a stored data into a new picture data in order to save a recording material, and a picture printing means. The picture data changing means changes the stored picture data into a new picture data in order to save a recording material only when a saving command of a recording material is given. The new picture data includes smaller dots than the stored picture data and/or has a fewer picture dots than the stored picture dots. As a result, the new picture data enables the picture printing means to save a recording material.

Abstract: An image forming apparatus according to the present invention comprises image forming unit for forming an image from a plurality of first pixels having a predetermined size, and smoothing processing unit for executing a smoothing process by controlling the image forming unit so that picture elements situated near the outline of the image formed by unit of the image forming unit are composed of second pixels having a size larger than that of the first pixels.

Abstract: A tone image processing apparatus comprises a setting device and a generating device. The setting device sets a plurality of tone levels in accordance with image density of an original. For reproduction an image of the original, the generating device generates a plurality of density values corresponds to the tone levels. The difference between one density value and next density value is increased over all the tone levels as the tone level becomes higher.

Abstract: An image forming apparatus has an electrophotographic photosensitive member with a support, a photosensitive layer with a thickness (T), a charging subunit, an exposure subunit, a developing subunit, and a transfer subunit. The exposure subunit illuminates the charged photosensitive member with a light beam having a spot area (S), such that the product S.times.T is 5,000-12,000 .mu.m.sup.3.

Abstract: Bit data of a received video signal is partially converted into a first signal representing a data sequence corresponding to the resolution of an LED head. The remaining bit data of the received video signal, which are not converted into the first signal are converted into a second signal representing another data sequence corresponding to the resolution of an LED head. The LED head includes a resolution conversion circuit which converts the video data into the first signal and the second signal. The signals are stored in a shift register having a plurality of line buffers. The first signal is printed on a basic raster line and the second signal is printed on an additional raster line. An LED head drive energy with which basic raster lines are printed and another LED head drive energy with which additional raster lines are printed are set independently of each other.

Abstract: A method that changes the image length and width produced by a laser printer to bring the printer's printed output into exact dimensional accuracy with the data input. This is accomplished by first a measuring sample page produced by the printer in response to a known input. Errors, if any, are measured and fed back into the printer through a host computer, and the graphics controller uses this information to change the printed graphics in the vertical and horizontal dimensions. In one embodiment of the invention, the graphic depiction is scaled as it is converted from the display list to the dot image in the printers RAM. In another embodiment, the resolution of the controller is changed to compensate for errors.

Abstract: A line width controlling method for controlling a line width of a toner image includes adjusting pulse width signals for controlling light beam emission of a laser beam generator; forming a latent patch image, comprised of plural latent line images, on a photoreceptor by irradiating a light beam from the laser beam generator; and developing the latent patch image with toner so as to form a toner patch image comprised of toner line images. The steps of forming the latent patch image and of developing the latent patch image to form the toner patch image are both repeated for a plurality of times. The toner patch image at each time of forming has a different gradation from that at other times of forming, so that a series of toner patch images is formed on the photoreceptor.

Abstract: An image forming apparatus which automatically adjusts an image density when at least one of conditions of an optical writing operation, including a size of a dot image, a light strength of a laser beam, a mode of image resolution, and a scanning speed of the laser beam, is changed. When an instruction by an operator for changing the conditions of the optical writing operation is input, an optical writing controller executes a change of the conditions and a process controller then executes an operation of determining a development potential and associated bias potentials on the basis of the changed conditions of the optical writing operation. In the operation of determining a development potential and associated bias potentials, a predetermined reference dot image is written on a photoconductor by a laser beam under the changed condition of the optical writing operation and is developed with color toner under the determined development potential and associated bias potentials.