Abstract: A head driver for thermal printing drives plural heating elements in a heating element array according to heating data for respectively the plural heating elements, to record dots of one line thermally by heating color thermosensitive recording material. A first data train is output, including gradation level data of gradation levels 0, 2, 4, . . . , 510. One-line image data for plural pixels in the one line is serially compared with the gradation level data in the first data train, so as to create even number gradation heating data in a serial signal form. Simultaneously with the first data train, a second data train is output, including gradation level data of gradation levels 1, 3, 5, . . . , 511. The one-line image data is serially compared with the gradation level data in the second data train, so as to create odd number gradation heating data in a serial signal form. After transfer to the head driver, the even number gradation heating data is converted into a parallel signal form.

Abstract: In an image forming method in which a dither matrix comprised of a plurality of dots are used to record one pixel and an image having multistage gradations is recorded by changing the diameter of this dot, a threshold value of a dither matrix in one pixel is arranged such that each dot is sequentially plotted in the scanning direction of a thermal head. Further, in response to gradations, an image is recorded without using a dither matrix of a threshold value in which an energization time of a thermal head becomes discontinuous.

Abstract: A multi-gradation recording method wherein the recording energy in high density region can be reduced, and the rough appearance in low density region or high density region and notchy appearance in profile or line of the image can be reduced while maintaining the level of reproduction of intermediate tones obtained by the conventional recording method using the zigzag pattern or the stripe pattern is provided which comprises: using a printer of the type wherein each one pixel is formed by using each one recording element and the optical density of the pixel formed is represented by the magnitude of the area of the pixel, dividing input data into two or more groups with respect to the data corresponding to pixels to be arranged in principal scanning direction, correcting the data of each group on the basis of the corresponding &ggr; correction data, the &ggr; correction data for the respective groups being different from each other, and performing recording on the basis of the corrected data wherein the pixels

Abstract: In a non-impact recording apparatus that includes a plurality of recording elements, there is provided a source of first data signals representing for each of plural pixels density, size or percentage of coverage for recording. A first look-up table memory is responsive to the first data signals for adjusting the density, size or percentage coverage of each of the pixels with a gamma adjustment related to density development by the apparatus and generates multibit gamma adjusted second data signals. A second look-up table memory generates a third signal related to a characteristic of the recording elements such as for nonuniformity correction. A process look-up table memory is responsive to the gamma adjusted second data signals and the third signals for generating fourth multibit signals relating to exposure on-times for recording pixels by the recording elements. The use of the three look-up table memories results in substantial saving in memory requirements.

Abstract: A variable speed print apparatus and method provide for adjustment of the effective print speed for each print line being printed on the work piece by determining a maximum shade value to be printed on each print line and adjusting the print speed for each line accordingly. When there is no printing on a given line of the work piece, that print line may be effectively skipped altogether.

Abstract: In image recording, density correction is performed by an improved method in which the image densities on a density correcting reference chart that have known densities which are associated with a visual density are measured with a densitometer for setting the density correcting conditions, the correcting conditions for correcting the values of measurement with the densitometer such that they coincide with the image densities on the reference chart are constructed from the image densities on the reference chart and the values of measurement with the densitometer, and the density correcting conditions are set in accordance with the constructed density correcting conditions. Alternatively, the density correcting conditions are set in consideration of a threshold for color formation to occur in the thermal recording material or the maximum heating time in thermal recording is controlled.

Abstract: In the improved shading compensation method applied to thermal recording for recording on a thermal recording material by using a thermal head having a glaze in which heat-generating elements are arranged in one direction, and by relatively moving the glaze and the thermal recording material in a direction perpendicular to the direction in which the heat-generating elements are arranged, with the thermal recording material being kept in contact with the glaze, a plurality of shading compensation tables corresponding to different recording densities are used and the weights of the plurality of shading compensation tables are changed in accordance with the recording densities, to thereby calculate conditions for shading compensation.

Abstract: A recording sheet is fed two times for recording of one line. Two recording operations corresponding to the respective sheet feeding operations are performed in a dispersive manner based on gradation data that are different for the respective sheet feeding operations. For example, binary data for the first and second recording operations are generated by comparing the gradation data with odd-numbered and even-numbered gradation reference values, respectively.

Abstract: A method of recording an image in which a multicolor image is recorded by moving in a subscanning direction a head having recording elements arrayed in a main scanning direction to make variable the density or area ratio of each pixel in correspondence with an image density, and by combining the colors of yellow, magenta, cyan, and black, wherein each color is recorded by dots arranged at a fractional dot cycle in the sub canning direction, so as to prevent color moire due to misregistration.

Abstract: The improved thermal recording apparatus for forming an image in accordance with image data on a thermal recording material using a thermal head comprises a correction data storage unit for holding shading correction data for the image data and at least one of weighting functions for performing weighting on a coefficient of shading correction of the image data, and an image processing unit that weights the shading correction data on the basis of at least one of the weighting functions, that calculates the coefficient of the shading correction and which then performs at least the shading correction on the image data. The correction data storage unit holds at least one of the respective weighting functions of shading correction coefficient associated with a recording density of the image data, a temperature of the thermal head, a recording speed of the image, temperature and humidity of the thermal recording material and a gradient of the thermal recording material.

Abstract: A light-amount correction dynamic range expanding device that can increase the number of exposure gray levels without increasing the memory capacity of the storage section for light-amount correction. Input data is formed of (n+k) bits to increase exposure gray-scale level. A first look-up table stores the output densities to the number of exposure gray levels for photosensitive substances classified by photosensitivity. Of (n+k) bits output from the first table, a first selector selectively outputs only effective n bits to a second table 2 to use m bits needed for a photosensitive substance. The second look-up table stores brightness information to correct variations in brightness between luminous dots of a print head, with a memory capacity of n bits. A FIFO memory temporarily stores the brightness information. A selector 2 again converts the output from the FIFO memory into a (n+k)-bit form and ten it to a gray-scale control means.

Abstract: A method for processing a digitized continuous tone image so that such processed image is adapted to be applied to an image rendering device which prints dots from a set of two or more possible dot-areas and from a set of colorants having different colorant concentrations is disclosed. The method includes selecting a set of N dot-area and colorant concentration combinations, each of said combinations producing a different integrated optical density value and multilevel halftone processing the digitized continuous tone image to produce an output image having a set of output levels wherein one member of the set of N dot-area and colorant concentration combinations is associated with each of the possible output levels.

Abstract: A multilevel image recording method is provided which can reproduce high resolution images with high quality and at a linear gradation. One pixel is formed by a left dot and a right dot, and a density of the pixel is expressed by a sum total of surface areas of each dot. The density of the pixel is distributed to the left dot and the right dot in accordance with curve A or curve B. At least dots expressing maximum densities at respective pixels in halftone regions are right dots.

Abstract: An image receiving sheet comprises a paper substrate, a foamed layer formed on a paper substrate and a color receptor layer formed on the foamed layer. The image receiving sheet and an ink sheet are attached to each other in an overlapped fashion so that a printing energy from the thermal head is applied to all printing area at a time of image forming, the printing energy including an image-wise energy corresponding to image data and a background energy being applied to all printing area of the image receiving sheet and being defined in a look-up table, the image data is controlled by the look-up table.According to a thermal transfer recording method of the present invention, a good quality image can be formed on the image receiving sheet.

Abstract: A thermal head has a heating element array with a plurality of heating elements disposed in line and a head driver. The head driver drives the heating elements at the same time in accordance with each set of heating data of 8 bits to record dots of one line on a recording sheet. In printing dots by using heating data of 9 bits, a heating data divider circuit divides the 9-bit heating data into two series of 8-bit converted heating data. By using these two series of the 8-bit converted heating data, two heating sequences are continuously executed. Each heating element is heated by the two heating sequences as many times as that corresponding to the heating data.

Abstract: In the improved thermal recording method in which image data supplied from an image data supply source are subjected to specified image processing jobs and in which a thermal head is driven in accordance with the processed image data so as to perform thermal recording, image processing jobs are performed in a specified order such that sharpness correction and tone correction are followed by shading correction and correction of resistance values which, in turn are followed by compensation for temperature elevation, provided that calculation treatment of respective values of the image data for the compensation for temperature elevation is performed either prior to or after either one of the corrections that are performed subsequent to the tone correction. It is preferred that black ratio correction and/or load variation correction are also performed after the shading correction and the correction of resistance values, and prior to the compensation for temperature elevation.

Abstract: A thermal printer head (TPH) heating method for minimizing the change of temperature and voltage of the TPH and an apparatus adopting the same, including the steps of: generating successive gradation values which oscillate between the minimum and the maximum gradation values and converges on a medium value M; comparing the gradation value generated in the gradation value generating step with the pixel value; and providing the result of the comparing step to the TPH. Therefore, the heat accumulation phenomenon is reduced by uniformly distributing the heat amount of the TPH over the time and space axes so that the TPH function is improved.

Abstract: A method of activating a binary controllable element of a thermal head in correspondence with an N-bit data value representing a density value D by converting a digital signal representative of said N-bit value into a binary signal that, when applied to said transducer under control of a strobe signal, causes said physical value D to be generated. The binary signal is composed so that it is active during a period t.sub.on, wherein t.sub.on is equal to the sum of a number of time steps being selected from at least two different predefined time steps.

Abstract: A method and apparatus are described for employing non-uniform quantization to avoid marking dots within a region where there is inadequate control of marking density or color. The techniques are typically applied to dye transfer media used in thermal printers where the dye transfer media has a potential variance among lots. Dithering modifications are described for use with non-uniform quantization to provide control of color marking in areas where the energy input into a dye transfer medium results in an output that can vary between different lots of the transfer medium. Error diffusion may also be used with such non-uniform quantization.

Abstract: A printer apparatus in which a multi-nozzle print head can be produced at low cost and which can deal with changes caused with lapse of time. With the printer apparatus, effective resolution can be improved and a more accurate gradation level in picture printing can be achieved for assuring uniform printing quality. The printer apparatus has a shading correction unit 14 for correcting the picture printing data signal for printing using shading correction data previously found and stored in the EE-PROM 10 and shading correction data entered from a man/machine interfacing unit 2 and for generating a head impression signal for driving a print head 16 based on the corrected picture printing data.

Abstract: A method and a printer are provided for printing on a thermosensitive paper by using a thermal head which has a plurality of heating dots arranged along a line extending in a primary scanning direction. The heating dots are selectively actuated according to sets of printing data for heat generation to form printing dots on the paper. The paper is fed pitch by pitch in a secondary scanning direction substantially perpendicular to the primary scanning direction. Each of the heating dots has a heating length in the primary scanning direction and an effective heating width in the secondary scanning direction, the effective heating width being smaller than the heating length.

Abstract: An ink jet recording apparatus and method for forming an image including a text region and a halftone region. The text region contains at least a part of a character and/or a thin line thinner than a predetermined thickness, and the halftone region contains a dot image on a recording medium. An image is formed by ejecting ink from recording heads in response to an input signal. The apparatus or method identifies the text region and the halftone region of an image on the basis of the input signal, expels black ink onto a recording area on the recording medium so as to form at least a part of the text region in a first scanning of the recording heads, expels a plurality of inks including the black ink onto the recording area so as to form at least a part of the text and the halftone regions in a second scanning, and repeating the first scanning and the second scanning on the next recording area after incrementing the recording medium.

Abstract: An apparatus and method for generating all of the print levels represented by an image data signal using a parallel input print head which has an input data bus which is narrower than the image data signal involves processing and printing image data multiple times. Each time the image data is processed, it is reduced from its original width down to the width which the print head can accept. The process includes the steps of determining the minimum number of times L.sub.min that the print head must be loaded to accomplish printing using the full width of the image data signal; processing the image data L times, where L.gtoreq.L.sub.min, to produce L output signals that (1) are no wider than the width of the input data bus and (2) have values such that the sum of the values of the L output signals equals the value of the input data signal; and using the L output signals to drive the print head.

Abstract: A gradation control method in a color thermal transfer printer is adapted to express one pixel by a dot matrix with two rows and two coles, control a density value of one dot with a time for energizing a heating element of a thermal head, and carry out mask patterning for plotting only one of four dots when the gradation of each color for one pixel is not more than a prescribed value while plotting only two of the four dots when the gradation is in excess of the prescribed value. At this time, employed is a mask pattern of necessarily plotting cyan and magenta on dots which are different from each other. A picture quality improving method in a staggered printing system is adapted to plot a noted dot when at least one of such conditions that density data of the noted dot is in excess of a prescribed density value and that density data of any of four dots most approximate to the noted dot is not more than a prescribed low density value is satisfied, even if the noted dot corresponds to that to be masked.

Abstract: A method and apparatus proecsses a dot image formed of a plurality dots, each dot having a density level. In the method and appratus, a dot pattern is extracted from the dot image, which dot pattern being formed of an observation dot and dots surrounding the observation dot, it is tdetermining, based on comparison between the extracted dot pattern and predetermined reference patterns, whether or not the observation dot in the dot pattern is either a dropout dot or a projection dot, a density level of the observation dot is changed to a first density level corresponding to the dropout dot when it is determined that the observation dot is the dropout dot, and a density level of the observation dot is changed to a second density level corresponding to the projection dot when it is determined that the observation dot is the projection dot.

Abstract: The present invention is made to effectively prevents the occurrence of undesirable dot patterns in the process of FM screening. Threshold values in an M1.times.M2 threshold matrix are determined using a plurality of fundamental tiles of 2.times.2 dots in size. The method of the invention arranges the plurality of fundamental tiles in the M1.times.M2 threshold matrix region, while not allowing the fundamental tiles to have preset forbidden arrangements. This gives a 50% dot pattern including 50% black dots and 50% white dots. The values `0` and `1` are assigned as the upper-most paired bits of digital data representing a threshold value to the positions of two black dots in each fundamental tile, and the values `2` and `3` are assigned as the upper-most paired bits to the positions of two white dots. The values of the other paired bits included in the digital data representing a threshold value are determined by successively dividing the M1.times.

Abstract: Disclosed is a method for forming an image in a recording material and transferring said image from said recording material to an image receiving material in order to produce a transferred image in said image receiving material, comprising the steps of: exposing said recording material, wherein said recording material comprises a support, a colorant layer containing a colorant, and a colorant barrier layer containing a light-absorbable substance in this order, said exposing causes to produce an ablated hole in said colorant barrier layer to form said image and said exposing is held with controlling means for exposing said recording material based on an image signal so that a size of said ablated hole in said colorant barrier layer is subject to change based on said image signal, said exposing means producing a light which is absorbed by said light-absorbable substance; and transferring said colorant from said colorant layer to said image receiving material through said ablated hole to produce said transferred

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 thermal transfer recording medium 2, used for a hot-melting-type thermal transfer print system using a hot-melting-type ink, comprises a substrate 2b, and a multi-grooved layer 2a formed on this substrate 2b. A plurality of thin grooves 2a1 are formed on a surface of the multi-grooved layer 2a. Each thin groove 2a1 has a width of 1-10 .mu.m and a length longer than a pixel at least in an auxiliary scanning direction. When a hot-melting-type ink 1a is transferred onto the thermal transfer recording medium 2, the ink 1a smoothly permeates into the thin groove 2a1 and extends along the elongated recess thereof, thereby providing an excellent multi-gradational image with excellent resolution and quality.

Abstract: An image printing device includes a latent image charge keeping medium including a pyroelectric layer, a thermal head for selectively heating the charge keeping medium according to a signal, and an electrically conductive film disposed to be brought into contact with or to be in the vicinity of a surface of the pyroelectric layer of the medium for being heated by the thermal head, thereby neutralizing charge appearing on the medium due to pyroelectric effect. The device further includes a developer for visualizing with a charged coloring medium an electrostatic latent image formed on the medium, a transfer roller for transferring the developed image onto a sheet of printing paper, and a fixing device for fixing the transferred image on the printing sheet. The conductive layer is applied with a bias voltage from a power source such that a strong absorbing force acts upon charge, thereby efficiently neutralizing the charge.

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: Thermosensitive color recording paper includes a support and three thermosensitive coloring layers formed thereon for yellow, magenta and cyan colors. The uppermost yellow coloring layer has the highest heat sensitivity. The undermost cyan coloring layer has the lowest heat sensitivity. When the yellow or magenta coloring layer is colored at high density, the next-underlying coloring layer is inevitably colored at a small amount. A thermal head has heating elements which are respectively driven by a pulse train constituted of a bias pulse and gradation pulses. The bias pulse raises the temperature up to coloring temperature to record one pixel in each coloring layer. The number of the gradation pulses represents the density of recording on the pixel. The bias pulse is divided into two. The gradation pulses are grouped into two groups.

Abstract: For tone control of a thermal transfer type color printer, an image data of red (R), green (G) and blue (B) is converted by a color conversion circuit into an image data of yellow (Y), magenta (M) and cyan (C). The respective 8-bit Y, M and C image data from the color conversion circuit are converted to 12-bit image data by a look-up table. A converter circuit divides 256 tone levels represented by the upper 8 bits of the 12-bit image data as an integer portion and the lower 4 bits thereof as a decimal portion to a first region whose tone level is equal to or lower than a predetermined tone level and a second region whose tone level is equal to or higher than the predetermined tone level.

Abstract: A thermal head has a plurality of heating elements disposed in line. These heating elements are grouped into sets of four heating elements. Each set records one pixel which is constituted by 4.times.8 cells disposed in a matrix shape. Each cell is selectively recorded with an ink micro dot. A blank section record an nth pixel, and immediately before each heating element faces the first main micro line of an (n+1)th pixel. In the course of this blank section, each time the thermal head moves by a predetermined distance, each heating element is driven by drive data which does not make the heating element turn on. In a preferred embodiment, if an nth pixel has a low density, each heating element is selectively driven to the extent that an ink micro dot is not recorded, so as to preheat the selected heating element in the course of the blank section.

Abstract: A method and apparatus of recording an image by digital information on an analog record material, in which the image information is stored as gradation image data representing figure image and binary data representing character image. The binary data representing character image is stored as a state of micro lines representing the character image. The gradation image data of each pixel is converted to binary data representing a plurality of parallel micro lines forming the each pixel, gradation in each pixel being represented by the number of the micro lines. The image is recorded on the analog record material by means of the micro lines corresponding to the binary data of the gradation image and character image.

Abstract: A gradation data processing method for shortening printing time by processing a signal per bit column makes a heating element generate heat in the mid portion of one line printing time for a low gradation and makes the heating element repeatedly generate heat in all ranges during high gradation printing. The gradation data processing method includes steps for storing per line an N-bit picture data capable of expressing the 2.sup.N gradation, reading per predetermined bit column the N-bit picture data capable of expressing the 2.sup.N gradation and printing per the predetermined bit column the picture data read during the reading step while allowing the picture data to have respectively different heating time per the predetermined column.

Abstract: There is disclosed a driving device for a recording head such as a thermal head or an ink jet head driven in plural blocks, which is capable of avoiding formation of division lines, or low-density streaks, in the recorded image at the boundaries of the driving blocks of the head. In this driving device, the time difference between the start of pulse application to a heat generating element of the recording head and that of an adjacent element is maintained so as not to exceed the maximum pulse duration to the heat generating element. Also, a group of plural heat generating elements positioned at the boundary of two divided blocks is activated simultaneously with each of the two divided blocks.

Abstract: Ink is transferred to an image receiving paper by a thermal head having a plurality of heating elements. The tonal level of a half tone image is expressed by the size of an ink dot recorded in a print pixel. The pixel density is changed in accordance with a smoothness of the surface of an image receiving paper and an image density. The size of a print pixel becomes large as the image density becomes low. If a high quality image receiving paper having a smooth image receiving surface is used, one ink dot per one print pixel is recorded by driving one heating element independently from the image density. If a standard paper having a round image receiving surface is used, for a highlight image area, three consecutive heating elements are driven at the same time to record a large size ink dot in a large size print pixel so as to ensure a reliable ink dot transfer.

Abstract: A printer for recording a multitone image in which pulse width correction data is generated based on a temperature output of a thermistor for detecting the temperature of a head mount of a thermal head and an output of a data cumulating circuit for cumulating pulse width data inputted to the thermal head; and an adding circuit which adds the pulse width data to an output obtained by conversion, from inputted tone data, made by a .gamma. correcting circuit, thus accomplishing a temperature compensation. The temperature compensation constants necessary for calculating pulse width correction data are also determined.

Abstract: In a thermal recording method of recording an image on a recording medium and a thermal recording apparatus using this thermal recording method, image data is divided into blocks in units of a plurality of bits to convert the blocks into recording head drive data, and a pulse width of a strobe signal corresponding to each bit of the converted drive data and a count of drive data arrays applied to a head are controlled to perform halftone image recording.

Abstract: An image forming apparatus includes a dot forming unit responsive to a drive signal for forming a dot on a pixel when the drive signal is indicative of forming the dot to reproduce a halftone image. The apparatus further includes a drive signal generation circuit for generating the drive signal according to a video density signal, a deletion signal, an addition signal, and a directional signal. The deletion signal indicates that the video density signal of the pixel shows a shadow level and there is a first edge adjacent to the pixel in a first image around the pixel. The addition signal indicates that the video density signal of the pixel shows a highlight level and there is a second edge adjacent to the pixel in a second image around while the pixel, the directional signal indicates a direction of the first and second edges from the pixel. The drive signal is pulse-modulated by the video density signal.

Abstract: A gradational printing method for performing a gradational printing by energizing a plurality of heat emitting elements arranged on a thermal head correspondingly to respective bits of digital gradation data representing a gray level. In case of this method, the plurality of heat emitting elements are divided into two or more blocks and the blocks are energized correspondingly to different bits of the digital gradation data. Thus, an energizing time, during which a maximum current should be supplied, can be reduced. Further, the weight of the printer can be light. Moreover, if the maximum electric current of a printer is equal to that of the conventional method, the duration thereof can be equal to the minimum duration of the energizing pulses corresponding to the bits of the gradation data. Consequently, the capacities of a power supply and a printer employing this method can be small. Further, the size and manufacturing cost of the power supply and the printer can be small.

Abstract: A fusion-type thermal transfer printing system using an ink ribbon having a thin film and a heat fusible ink applied on the thin film at an ink application rate of 2.5 g/m.sup.2 or less and a porous-surface recording medium having a substrate and a porous-surface layer formed on the substrate, diameters of pores in the porous-surface layer being from 1 to 10 .mu.m. The printing system has a thermal head provided with a plurality of heating resistors formed in a line at regular intervals of 8 dot/mm or less, temperature gradient of each of the heated heating resistors being such that temperature is the highest at a middle portion thereof and changes decreasingly toward ends thereof and a gradation control circuit for controlling ink fusion areas heated by the heating resistors by controlling intensity of current passed through the thermal head.

Abstract: A method of compensating for resistance tolerances in the printing of a multi-tone picture with a printing device which includes printing elements. Starting from a smaller number of required tone grades than the number of available tone grades, represented by energy values, printing is always effected with those available tone grades whose available optical density comes close to the required optical density. The differences between the required optical density and actually available optical density are added to form a mean deviation whose magnitude is minimized by selecting the corresponding available tone grade so that the created visual picture has the required optical density.

Abstract: Half-tone image data and character image data are discriminated from each other with reference to discrimination data, and are stored separately from each other. In accordance with the image to be printed, one of a character print table and a half-tone print table is selected. In accordance with the result of comparison of the character image data with comparison data read from the character print table, characters are recorded using two kinds of character dot print patterns for recording a dot in the whole area of an associated pixel and for recording no dot. Half-tone images are recorded in the area gradation method using half-tone dot print patterns in accordance with the result of comparison of the half-tone image data with comparison data read from the half-tone print table. One pixel is divided into a plurality of sub-lines. The recording of the characters is performed at intervals of N sub-lines, N is an integer. The recording of the half-tone images is performed at intervals of one sub-line.

Abstract: A medical image forming method including, the steps of superposing a three-primary-color thermal transfer sheet and an image receiving sheet, the thermal transfer sheet having a base film and three color dye layers of yellow, magenta, and cyan, each of the dye layer; being composed of a dye and a binder, the image receiving sheet having a dye accepting layer heating the rear surface of the thermal transfer sheet with a heating device in an image shape; and driving and controlling the heating device with a control unit so as to form a full color image on the image receiving sheet. The control unit is adapted to compensate tones of the image so that chromaticity values thereof formed on the image receiving sheet are in a region defined by four points of (a*=0, b*=0), (a*=20, b*=-5), (a*=18, b*=15), and (a*=0, b*=15) when an achromatic color signal is input and L*=80.

Abstract: An area gradation control device and method for a thermal printing thermosensitive recorder, such as a color video printer or a facsimile, performs a printing operation by converting color-corrected and gamma-corrected data into area gradation signals. One bit among 8-bit data is sequentially selected according to gradations and transmitted to a thermal printing head, and strobe pulses whose number corresponds to the weight value of each bit are provided to the thermal printing head for each time a selected significant bit is provided to the thermal printing head, so that dye deposition is uniformly performed over the overall area of a pixel with a high data processing speed.

Abstract: Image data representing one pixel line and supplied from a line memory are divided by a dividing circuit into three sets of image data which are stored in respective line memories. A switcher is controlled by a timing signal from a controller to successively supply the image data from the line memories to a thermal head driver. Based on the supplied image data, the thermal head driver enables a thermal head to record three lines on a thermosensitive recording medium. The thermosensitive recording medium now records thereon a high-quality image free of coarse image textures which has recorded image areas dispersed in one pixel interval in the direction in which the thermosensitive recording medium is fed.