Abstract: A non-impact printer apparatus includes a printhead having a plurality of recording elements. Nonuniformities in emission characteristics of the recording elements are corrected using look-up tables (LUT) assemblages that include a first LUT wherein the recording elements are binned in accordance with bin values associated with their emission characteristics and a second LUT wherein bin values, output from the first LUT are used to address various tables providing exposure correction. The first and second LUTs are advantageously dual port RAM devices that allow operation during printing while simultaneously allowing loading of data into the tables for use for subsequent printing. Thus, process conditions may be continually monitored and correction data updated without delaying of current printing which may occur using correction data already stored in the LUT assemblages.

Abstract: Higher quality printing is difficult in implementation in spatial light modulator printers. The two major problems are accomplishing gray scale within the line time constraints, and eliminating staircasing artifacts within the images printed (81). It can be improved by using an alternate way of resetting cells on the spatial light modulator when data is being loaded onto the cells, timing delay (86), horizontal offset (84), and differently sized pixels (80, 82).

Abstract: A radiation beam is generated by a radiation source such as laser. An optical system focuses the radiation beam at a recording layer (in a disc-shaped carrier) of a type in which an optically detectable change is caused to take place if the recording layer is heated to above a write temperature. The recording layer is scanned by the radiation beam by means of a motor. A control circuit feeds the radiation source with electric power which is converted in the radiation source partly into heat and partly into radiation for the radiation beam. The control circuit operates in a read mode in which the power supplied to the radiation source has a value at which the rise in temperature of the recording layer caused by the radiation beam is insufficient to cause an optically detectable change to take place.

Abstract: A copier/printer system includes an image scanner for scanning a document and providing, after a compression step, digital image scanning signals, P.sub.1, that may be communicated to a computer system for display and editing or alternatively communicated to a grey level printer having a magnetic tape memory. The computer system may be used to display the scanned image for editing by an operator and is coupled to the printer so that the edited image signals, P.sub.2, which may be the scanned signals and a common page description language to modify its usage, may be printed by the printer. The edited image signals, P.sub.2, may be sent to the printer over a suitable network. The printer includes image processing electronics for transforming the edited data, P.sub.2, into device independent data signals, P.sub.3. Such signals may be received by printers of the same type; i.e., those employing similar process and halftone algorithms. The signals, P.sub.

Abstract: A method for producing a calibrated printhead having a plurality of light-emitting recording elements such as LEDs includes the steps of (a) burning-in the recording elements until a further aging characteristic of the recording elements is in a generally linear range; (b) measuring a light intensity emitted by each recording element after the burning-in in step (a); (c) establishing a target value for additional burning-in of at least those recording elements having measured light intensities above a minimum measured light intensity for a recording element; and (d) respectively providing additional burning-in to those recording elements towards the target value. An apparatus including the calibrated printhead has no data provided to the printhead which is corrected for relative non-uniformity of the recording elements to each other.

Abstract: This invention relates to a laser marking method which comprises heating a base article having on its surface a thin film of a laser marking composition containing a color former and a color developer having a melting point of 200.degree. C. or above, and then applying laser light to the thin film. The method of this invention is capable of no-break marking with vivid color development by application of laser light, without causing discoloration of the ground even under a condition of 120.degree. C. or above.

Abstract: An imaging apparatus modulates or gates pluralities of light beams through individual light valves, thereby providing a greater number and finer resolution of modulated light beams without increasing the number of light valves or decreasing the spacing between adjacent light valves. A two-step modulation process is used, the first step being performed by a light generator incorporating a polygon mirror that selectively illuminates selected bundles of fiber optic strands. One strand from each bundle is routed to illuminate one of the cells in a light valve array, such that when a bundle is illuminated, every cell is illuminated by a strand from the illuminated bundle. The second step of the modulation process involves controlling the light valve array to modulate the light beams formed by the illuminated strands at each cell.

Abstract: In an LED head operated on a time sharing basis, a multiplexer switches resistances for determining LED currents on LED arrays and assigns appropriate resistance to each array. The multiplexer is operated by block select signals of a block select circuit for time sharing operation, where the number of resistances corresponds to the number of blocks. The multiplexer capacity may also be less than the number of blocks, where the number of resistances less than the number of blocks and the same resistances correspond to more than one block. Output dispersions between arrays are adjusted by appropriate assignment of the resistances. sharing operation. Capacity of the multiplexer correspond to the number of blocks required for time. Gray scale printing is achieved by switching the current determining resistances in accordance with shading degree of image with the multiplexer.

Abstract: A CPU calculates an optimum inclination angle, an optimum movingspeed (V.sub.X) and an optimum displacement time of delay timing on the basis of input signals commanding resolution, a rotation cycle (T) and the number of beams, supplied from an operating part, and outputs a control signal (V.sub.CONT4) providing the inclination angle to a motor (9). As the result, an LED holder (30) rotates with respect to a central axis (37) at the inclination angle and stops. A zoom lens (24) is adjusted by a control signal (V.sub.CONT3) providing a magnification which is responsive to the resolution. A motor (7) is driven by a control signal (V.sub.CONT2), to drive an exposure head (20) at the moving speed (V.sub.X). A cylinder (36) rotates by a control signal (V.sub.CONT1) in a subscanning direction (Y) at the rotation cycle (T). As the result, an image forming region (34) is inclined with respect to the central axis (37) at the inclination angle.

Abstract: A method and apparatus for calibrating a gray level recording printhead having a plurality of light-emitting recording elements is described. In the calibrating method a light intensity of each recording element is measured. The light intensities measured are quantized into M first cells. For each cell an exposure time t (i, j) is determined wherein i is a number representing number of cells and varies from i=1, . . . M and j is a number greater than one representing a number of gray levels. The set of exposure times {t (i, j)} is sorted to remove duplicate times and define a subset of exposure times {t (k)}. A non-uniformity constant value u is associated with each exposure time t (k). Boundaries for plural second cells are defined wherein exposure times, t (k), within a cell are spaced within substantially about the value u from a time b (n) that is calculated from a cell boundary and also falls within the boundaries of each cell.

Abstract: A method and apparatus for grey level printing includes a plurality of recording elements which are enabled for variable periods of time during a cycle of recording grey level pixels. For each recording element a comparator compares the count in a time-changing exposure counter with a multibit grey level data signal. The exposure counter is decremented/incremented by exposure clock pulses from a programmable exposure clock. The exposure clock includes a master clock and an address counter that provides an incremented address signal in response to each set of N pulses from the master clock. The address signal identifies a location in memory of a set of signals used to generate exposure clock pulses. The set of signals is output in parallel to a serial shift register and shifted out serially to form the exposure clock pulses for decrementing/incrementing the exposure counter.

Abstract: A circuit for driving an LED print head so as to be capable of printing a variety of gray levels, comprises a print controller for generating synchronizing signals and latch clock pulses to be applied to the LED print head, a video clock signal generator means for generating a predetermined number of video clock pulses in response to the sub-synchronizing signals, a video data generating means operated by the sub-synchronizing signals for generating a number of sub-data representing the contrast of one line data in response to the video clock pulses, a contrast mode decoding means for counting the latch clock pulses in one period of the sub-synchronizing signals to generate first, second, third and fourth enable signals, a contrast strobe pulse generating means for generating first, second and third strobe pulses of different periods in response to the first enable signal, and a drive circuit for logically combining the second, third and fourth signals and the first, second and third strobe pulses so as to dr

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 first signal is transmitted to the LED head in the form of a real printing data signal that is to be printed on a basic raster line in synchronism with a line timing signal. 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, and then stored in a line buffer. The second signal stored in the line buffer is transmitted to the LED head in the form of a real printing data signal that is to be printed on an additional raster line in synchronism with an additional line timing signal. The LED head drive energy with which the basic raster lines are printed and another LED head drive energy with which the additional raster lines are printed are set independently of each other.

Abstract: A non-impact printer is described for forming an image on a medium. The printer having:a linear array of recording sources for forming a multi-gradation latent image on a receptor surface, the linear array comprising a plurality of sub-sets of recording sources;an element for developing the latent image into a visual image;an element for transferring said visual image onto the medium;an element for generating and storing first correction factors derived from measurements of the non-uniformity of average energy output of each of the sub-sets of recording sources;first correction element for applying, for each sub-set of recording sources, the first correction factors;an element for generating and storing second correction factors derived from measurements of the non-uniformity of each individual one of the recording sources; andsecond correction element for applying said second correction factors after applying the first correction factors.

Abstract: Disclosed is a recording system in which an operation performed on the side of a printer unit in order to change over recording density is delayed while a recording operation is in progress. When a recording density changeover command is received during a recording operation, the density changeover is performed after the recording operation ends. A control unit which controls the printer unit is informed of the fact that the measures for changing over the recording density have been completed on the printer unit side.

Abstract: Higher quality printing is difficult in implementation in spatial light modulator printers. The two major problems are accomplishing gray scale within the line time constraints, and eliminating staircasing artifacts within the images printed (81). It can be improved by using an alternate way of resetting cells on the spatial light modulator when data is being loaded onto the cells, timing delay (86), horizontal offset (84), and differently sized pixels (80, 82).

Abstract: A print head for reproducing a multi-level image is an provided. In the print head, a light-emitting array comprises a linear line of light-emitting elements. A D/A converter converts a multi-level image data to an analog signal, and an analog shift register shifts and latches the analog signals of a line received from the D/A converter. An analog latch register latches the analog signals held by the analog shift register. A driver controls the quantity of light of the light-emitting elements according to the analog signals latched by the analog latch register. In one embodiment, the print head includes a second analog shift register, an A/D converter a line memory and a divider which divides the image data by a signal from the line memory to produce corrected data which is provided to the driver to control driving of the light-emitting elements.

Abstract: A LED printer utilizing a low resolution print engine for forming high resolution images is disclosed, in which a virtual 2N dpi high density image (latent image) is formed on a photosensitive medium by effectively turn-on controlling an array of LED elements arranged at a pitch of N dpi on a line in the main scanning direction.For each scanning line, a plurality of divisional exposure lines are produced for turning on the LED elements 2 m times (for instance 2.times.4 times) in the auxiliary scanning direction. For the turn-on control of the LED elements, weighted arithmetic operation values are obtained by multiplying the center bit and one or more adjacent bits thereto in the main scanning direction of the 2N dpi high density image data by respectively corresponding constants, and they are summed up to obtain sum data. According to the sum data the number of times of turning on the LED elements on the divisional exposure lines is controlled to form 2N dpi high density image on the photosensitive medium.

Abstract: An image smoothing apparatus which forms dot images on a matrix array and smooths images of curvatures or diagonals included in the dot images. The apparatus includes a shifting unit which shifts a specific pixel to generate first smoothing video data, thereby selecting a divided video data for defining a time interval and timing of the specific pixel, and a masking unit which subjects divided video data to a Boolean conjunction operation with a mask pattern to generate second smoothing video data. Smoothed video data for the specific pixel is formed by selecting suitable operations from among the shifting and masking according to the arrangement of reference pixels adjoining to the specific pixel.

Abstract: Higher quality printing is difficult in implementation in spatial light modulator printers. The two major problems are accomplishing gray scale within the line time constraints, and eliminating staircasing artifacts within the images printed (81). It can be improved by using an alternate way of resetting cells on the spatial light modulator when data is being loaded onto the cells, timing delay (86), horizontal offset (84), and differently sized pixels (80, 82).

Abstract: The present invention provides an image forming apparatus comprising a conversion circuit for receiving an image signal indicating the density of a pixel in an image formed from a plurality of the pixels arranged in a matrix of a main scanning direction and a sub scanning direction crossing at right angles and for converting the image signal into a signal indicating a coloring pattern corresponding to the density; and a printing device for receiving the signal indicating the coloring pattern and for printing the image on a medium by coloring each of the plurality of the pixels in accordance with the coloring pattern. In this image forming apparatus, each of the plurality of the pixels is divided into N sub-pixels in the sub scanning direction, wherein N is an integer larger than 1, and the conversion circuit generates, as the signal indicating the coloring pattern of each pixel, a signal indicating one of L patterns selected in accordance with the image signal, wherein L is an integer larger than N+1.

Abstract: An improved method for time delay and integration printing for gray scale. A gray scale represented by a bit pattern is provided for time delay and integration printing onto a photosensitive substrate. The pattern (12) is rotated about the light intensity cycle of the light source such that microbands in the final image are minimized or eliminated and sent to a spatial light modulator (10) for transfer to a printing substrate.

Abstract: A color printing system including thin film electroluminescent (TFEL) edge emitter devices and an electronic interface for driving the TFEL devices. The TFEL edge emitter devices form a multi-color TFEL edge emitter structure operable for emitting a plurality of different colors of light onto a media. The electronic interface receives gray scale data for pixels and converts it into a serial data stream used to drive pixels in the TFEL edge emitter structure. The electronic interface further includes a compensation memory for compensating for pixel variations in the TFEL structure. The compensation memory can be periodically recalibrated "in place" during the life of the printing apparatus.

Abstract: A non-impact recording apparatus for recording grey level exposures, the recording apparatus includes one or more recording elements such as LEDs. Image data signals of a predetermined multibits per pixel bit-depth dimension are generated by a data source along with a signal representing the predetermined bit-depth dimension. An exposure clock counter counts exposure clock pulses and outputs a count signal in response to clock pulses. The count signal represents a count value. A comparator compares a multibits-per-pixel image data signal with the count signal from the counter and generates a signal. A current driver is responsive to the signal from the comparator and controls a recording duration. Counting in the counter is adjusted in accordance with the multibits per pixel bit-depth dimension of the image data signal.

Abstract: A low-cost, high-speed system for converting high-grayscale-resolution image data to a grayscale resolution optimized for a particular output device, such as an LED bar or ink-jet printhead. A static random-access memory accepts at its address port a full image datum. The most significant digits of the datum relate to a look-up table selected for optimum performance in a given situation. The least significant digits of the datum represent the actual image datum. When the full image datum is applied to the address port, the address location identical to the full image datum outputs an output value which has been pre-loaded into the memory.

Abstract: A set of thinned halftone dot patterns useful in inkjet printing comprises a plurality of halftone cells corresponding to respective shade values. Each of the halftone cells includes a plurality of addressable points, with at least some of the points being turned "on" to define a halftone dot pattern, and at least some of the "on" points defining a core component of the halftone dot pattern being selectively turned "off", thereby producing a thinned halftone dot pattern. The thinned halftone dot patterns enable the use of higher addressability in an inkjet printing system to achieve a wider range of shade values while avoiding undesirable over-inking of printed halftone dot patterns due to excessive overlap between printed ink spots.

Abstract: A color image-forming apparatus comprises an electrophotoconductive imaging member moving in a first direction. A first corona charger forms an electrostatic charge on the imaging member. A first exposure device such as a laser or LED printhead imagewise modulates the electrostatic charge on an area of the member comprising an image frame. A first developer station develops a first visible image on the image frame with a pigmented toner of a first color. A second corona charger electrostatically charges the image frame having the visible image. A second exposure device such as a laser or LED device imagewise modulates the electrostatic charge on the image frame that was formed by the second charger. A second visible image is then formed on the image frame with a pigmented toner of a second color. The first and second visible images are transferred to a surface of a receiver sheet to form a two-colored image thereon.

Abstract: A recording apparatus has an array of recording elements arranged in a main scanning direction and having a predetermined dot pattern, and forms a dot image on a recording medium located opposite to the recording elements. Reception circuit receives image data of a predetermined dot density. A plurality of line buffers store one dot line of data of interest as a printing target among the image data and aligned in the main scanning direction, and plural dot lines of data preceding and following the one dot line with respect to a sub-scanning direction. A compensation data generating circuit converts the one dot line of data of interest as the printing target into N lines of compensation data, divided by N with respect to the sub-scanning direction, based on the plural dot lines of data preceding and following the one dot line. A control circuit controls the time for activating the recording elements based on the compensation data.

Abstract: In a printer head constituted by a large number of linearly arranged LEDs, a lighting time designator receives image data at a period corresponding to one scanning period, designates a lighting time of each LED within one scanning period in accordance with image data corresponding to each LED and the lighting capacity of each LED, and outputs lighting time data. A lighting mode designator determines a lighting mode for designating a timing, within one scanning period, at which each LED is caused to emit light, on the basis of image data, and outputs lighting mode designation data. A light timing controller divides one scanning period into a plurality of time intervals and supplies the lighting time data to the printer head a plurality of number of times within one scanning period at the time intervals on the basis of the lighting mode designation data, thereby selectively causing the respective LEDs to emit light.

Abstract: A method and apparatus for resequencing image data for a non-impact printer having a plurality of recording elements. A memory stores image data such that image data for plural recording elements are stored at one address location. The memory is sequentially addressed so that the data stored at successive addresses are sequentially output from the memory in a sequence suited for the type of printhead. A multiplexer controls the outputs from the memory so that only data in the correct sequence is output at each address location during a first empty cycle whereas other image data at each address location are output at subsequent empty cycles.

Abstract: A laser beam of a constant intensity is generated by a semiconductor laser and applied to a thermosensitive recording medium. The density of a colored recorded area of the thermosensitive recording medium is detected by a densitometer, and shading correcting data for making the density of the colored recorded area constant based on the detected density are stored in a shading data memory. A controller reads the stored shading correcting data and controls the intensity of the laser beam generated by the semiconductor laser based on the shading correcting data for thereby compensating for variations in the level of an image signal due, for example, to intensity irregularities of the laser beam applied to the thermosensitive recording medium and irregularities of the speed at which the thermosensitive recording medium is scanned with the laser beam.

Abstract: An electrophotographic printer uses plural recording elements such as LEDs for grey level recording. Redundant memory tables are provided that store redundant, but different, correction factors for correcting for nonuniformities of the LEDs at different grey levels. A nonlinear exposure clocking system is also provided for generating clock pulses at non-uniform intervals for use in controlling exposure durations for recording pixels. The clocking system includes a memory for storing binary signals that may be clocked out of a register and used as exposure clock pulses. The clock memory also includes redundant, but different, sets of possible clock pulses. As each new line of data is recorded, a signal is used to select one of the redundant sets of correction factors and a corresponding one of the redundant sets of exposure clock pulses.

Abstract: An image forming apparatus including an electrophotographic photosensitive member; a latent image forming device for forming an electrostatic latent image by charging the photosensitive member and exposing it to light information; a controller for controlling the latent image forming means to control tone reproducibility of the electrostatic latent image; an image forming device for forming an image having light, halftone and dark portions, for tone controls, a detector for detecting a state of the tone control image, and wherein the controller controls the electrostatic latent image forming device on the basis of a datum from the detector and predetermined tone correcting information.

Abstract: There is disclosed a printing apparatus implemented as a laser printer capable of changing the print format when outputting print data. When the operator changes the print format at the printer, the CPU changes the print data in a text buffer of a built-in RAM according to the changed print format, the data being converted into image data in a dot pattern for storage into an image buffer. The operator then pushes a reprint key, causing the CPU to read the pages of print data stored in the image buffer for outputting to a laser printer engine via a printer engine interface for reprinting. The printing apparatus allows the print format to be changed easily for efficient reprinting of the last print data in the new format without the need for the host computer to supply the same print data again.

Abstract: A raster output scanning system is disclosed which utilizes two light beams to double scan two scan lines on a photoreceptor in order to generate three exposure levels required for a tri-level printing system. In the raster output scanner of this invention, the two light beams scan two separate scan lines. At the completion of the simultaneous scanning of two light beams when the first light beam starts to scan a new scan line, the second light beam start to scan the scan line that the first light beam just completed scanning. In this invention the first light beam generates two exposure levels and the second light beam adds additional exposure to the second exposure level in order to generate a third exposure level. The same method can be utilized to generate additional levels for printing systems with more xerographic levels than three.

Abstract: A method for gray scale printing combining row integration and pulse width modulation. A spatial light modulator (102) has one line (104) designated to perform PWM within a given line time. Another area of the modulator (106) has lines designated to perform row integration on the print image, allowing for more gray levels. An additional area (108) can be designated to correct for defects in the illumination profile and the printed images.

Abstract: Techniques for achieving high resolution, high-speed gray scale printing with binary spatial light modulators. A spatial light modulator array is divided into subarrays, and the subarrays are illuminated at various levels (510, 512, 514, 516) of a modulated light source. Additionally, each pixel (520) can be divided up into four phases and printed in phase pairs.

Abstract: An array of light-emitting elements is switched on and off to produce a graded-intensity image on a photosensitive medium. Each light-emitting element is controlled by M-bit data representing the intensity of one image pixel, where M is a fixed integer greater than one. M strobe signals are generated for non-overlapping time intervals of different lengths, to strobe the M data bits for each light-emitting element. When strobed, each data bit switches its corresponding light-emitting element on or off. Image intensity depends on the total amount of time for which each light-emitting element is switched on.

Abstract: This invention modifies printing information from a laser scanner to improve the appearance of printed matter. This improvement takes into account the image data of a target pixel to be printed and the image data of adjacent pixels located before and after the target pixel, the pulse position of the target pixel. An operator can select whether to shift the radiation timing of a laser beam to the left or the right within one pixel, and whether to squeeze the laser beam to reduce its beam size or broaden it to increase its beam size.

Abstract: In a digital image forming apparatus with use of electrophotographic process, an electrostatic latent image is formed by modulating the intensity of laser beam according to image data to expose a photoconductor in the raster scan to form an electrostatic latent image. A scan line is divided into groups of consecutive dots, and the exposure of the photoconductor with the beam is allowed only for a predetermined light-emitting time within the time needed to scan a predetermined period of consecutive dots in the scan line direction. Thus, the exposure is stopped periodically and the smoothness of a reproduced image is improved.

Abstract: A hybrid halftone cell selection method enables selection of gray levels in halftone printing algorithms to minimize the effects of noise resulting in nonuniformities, such as, for example, halftone banding. The method requires selection of hybrid halftone cells possessing structures wherein the total number of gray pixels are limited. The number of gray pixels having any given intermediate reflectance level in any halftone cell is also limited. The cell selection method thus reduces the number of TRC gray steps to some minimum required number by eliminating the most noise sensitive cells (i.e. those cells having the highest percentage of gray level pixels). The intermediate reflectance values of the gray pixels in the selected cells are then selected to produce uniform gray steps and reduce variability in the TRC.

Abstract: A laser recording recording apparatus including a semiconductor laser as a light source and enabling half-tone recording. The apparatus includes a recording medium moving in a sub-scanning direction, M semiconductor lasers arranged along the sub-scanning direction at a slight distance to one another and enabled to be independently modulated according to image signals, where M is an integral number of at least two, a deflector for deflecting M laser beams emitted from the M semiconductor lasers toward the recording medium and for scanning the beams in a main scanning direction, and an image forming optical system for imaging the deflected laser beams at a predetermined distance between one another along the sub-scanning direction. An exposure pattern on the recording medium is represented by a pixel matrix comprising N.times.