Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
  • B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
  • B41J2/35—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads providing current or voltage to the thermal head
  • B41J2/355—Control circuits for heating-element selection
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
  • B41J2202/30—Embodiments of or processes related to thermal heads
  • B41J2202/33—Thermal printer with pre-coating or post-coating ribbon system

Definitions

• FIG. 5 is a block diagram of a controller for providing the various signals operating on the thermal printhead of Fig. 3 in accordance with the invention
• Fig. 6 is a circuit for enabling each recording element of the printhead in accordance with the invention
• Fig. 7A and 7B are timing diagrams illustrating various signals for operating the printhead of Fig. 3 and their relative relationship in the time domain in accordance with the invention
• Fig. 8 is a timing diagram illustrating a high-level strobe signal (HSTR) that is used to determine duration of enablement of a thermal recording element on the printhead of Fig. 3 and in accordance with the invention
• Fig. 9 is a timing diagram similar to that of Fig.
• the cyan dye transfer to the dye receiver sheet is in exactly the same area on the receiver sheet as was subjected to the yellow and magenta dye transfers and at pixel locations corresponding to where cyan dye is to be transferred to the receiver sheet. In many instances, cyan dye will be deposited directly over the yellow dye, the magenta dye or on pixel locations that include both the yellow dye and magenta dye at certain pixel locations as is well-known for creating different colors. 6. Once the cyan dye transfer is completed, the platen roller is retracted from adjacent the printhead to allow the dye receiver sheet to be returned rearward in preparation for exiting the printer. 7. Then, the pair of pinch and drive rollers advance the dye receiver sheet forward to an exit tray.
• the thermal printhead 52 comprises a series of heating elements arranged in a row directed in the main-scan direction of printing.
• the receiver and dye-donor film during printing are moved incrementally, line by line, in the slow-scan direction.
• the printer controller 40 is coupled by first, second and third outputs to the motors 42 and 44 and to the printhead 22, respectively.
• the motor 42 rotates the transport platen 24 to advance the receiver 28.
• the motor 44 rotates a drive roller 36 to advance the dye-donor film or ribbon 34.
• the thermal printer 20 functions under the direction of the printer controller 40.
• the printer controller 40 is a microprocessor-based control system.
• the printer controller 40 receives an image data signal from a conventional digital image source, such as a computer, workstation, digital camera or other source of digital data, and generates instructions for the printhead 22 in response to the image data. Additionally, the printer controller 40 has inputs 16 for receiving signals from various conventional detectors (not shown) in the thermal printer 20 which provide routine administrative information, such as a position of the receiver 28 a position of the dye-donor film 34, and the beginning and end of a print cycle, etc. The printer controller 40 generates operating signals for the motors 42 and 44 in response to said information.
• the printhead 22 performs a printing operation by selectively heating and thereby transferring spots of dye from the dye-donor film 34 onto the receiver 28.
• a receiver 28 and a portion of the dye-donor film 34 in a series of schematic relative positions to illustrate certain features of the thermal printer 20 of Fig. 1.
• the portion of the dye-donor film 34 is shown in the series of positions, Position A through Position F, with each position illustrating how the dye-donor film 34 is oriented relative to the receiver 28 in order to produce a particular portion of a desired image.
• the dye patches 50, 52 and 54 are coated on to the dye-donor film 34 in a gravure process that produces the dye patches each with a length Lp as is predetermined based on the nominal size of the expected regular prints to be produced by the thermal printer.
• the film 34 comprises a repeating sequence of yellow, magenta and cyan dye patches 50, 52 and 54 respectively which are each separated by a non-color portion or nontransferable separation of film 34a. If we assume for example that the nominal size of a print to be produced by the printer 20 is 3 1/2 by 5 inches, then the printhead 22 can be made five inches long and be the full width of the patch material and the length Lp of each patch in this example would be 3 1/2 inches long or slightly longer.
• the receiver 28 has a length Lr in the slow scan direction that is greater than the length Lp of the dye patches 50, 52 and 54 on the dye donor film 34.
• the receiver 28 is comprised of two regions Rl and R2 a portion of which regions overlap and the overlap region is shown as being between the dashed lines.
• Each of the regions Rl and R2 has a length that is no longer than the length Lp of one of the dye patches 50, 52 and 54.
• the regions Rl and R2 are shown overlapping by a distance Dl.
• the printer controller 40 of Fig. 1 first directs the motor 42 of Fig. 1 to advance the receiver 28 to a starting location. Typically, this starting location is determined as a point where a conventional sensor (not shown) senses a blocking of light from a light source (not shown) by presence of a leading edge of the receiver 28.
• the motor 42 then advances the receiver 28 a predetermined number of steps beyond the starting location.
• the dye-donor film 34 advances the dye-donor film 34 so the leading edge of the first one of the yellow dye patches 50 is positioned adjacent a leading edge of the receiver 28 (shown schematically as position A in Fig. 2). Then a first line of printing begins.
• the printing takes place on a line-by-line basis with the motor 42 advancing the receiver 28 and the dye-donor film 34 a predetermined incremental distance between successive lines of printing.
• the motor 42 incrementally advances the receiver 28 and the dye- donor film 34 throughout the generation of a first color (yellow) image on the first region Rl of the receiver 28.
• a constant tension is maintained on the dye-donor film 34 by the rollers 36 and 38 and the motor 44.
• motor 42 reverses and rotates the transport platen 24 in a counterclockwise direction until the leading edge of the receiver 28 has been withdrawn beyond the starting position.
• the motor 42 is then driven in the forward or clockwise direction until the leading edge of the receiver 28 is advanced to a position where printing of a second color image is to begin.
• the motor 44 advances the dye-donor film 34 so that a leading edge of a first one of magenta dye patches 52 is positioned (Position B) adjacent the leading edge of the receiver 28.
• the printing process is repeated to replace a second color (magenta) image on to the first region Rl of the receiver 28.
• a third color (cyan) image is printed onto the first region Rl of the receiver 28 (Position C).
• a first full-color composite sub-image (first sub-image) has been produced on the first region Rl of the receiver 28.
• the leading edge of the receiver 28 is returned to the starting position.
• the receiver 28 is then advanced so that a leading edge of the region R2 of the receiver 28 is aligned with the printhead 22.
• a leading edge of a second one of the yellow dye patches 50 is advanced to the printhead 22.
• the relative position of the receiver 28 and the dye-donor film 34 at this point is shown in Position D. Printing of a first color (yellow) of a second sub-image in region R2 then begins.
• the printing of the second sub-image begins in a region of the receiver 28 on which a partially complete segment of the first sub-image is already formed.
• a partially complete segment of the first sub-image is already formed.
• This process is repeated for each of the two remaining colors, magenta and cyan (see Positions E and F).
• a complete image is present on the receiver 28.
• it is necessary to accurately align the first and second sub-images.
• reference 100 denotes a strobe pulse table which defines a pulse pattern of the strobe signal HLSTR serving as a reference signal according to which the energization of thermal head heaters R 1 to R 1536 are controlled depending upon the printing mode.
• a strobe pulse table outputs a pulse pattern in response to a print mode signal MODE specifying the printing mode in which one of colors of yellow, magenta, cyan and optionally a transparent overcoat (where a quad patch is used). In the enlarged print mode the print mode signal MODE also is changed in accordance with the line number being printed as will be discussed further below.
• a microcomputer 90 controls the various motors, generators, converters and tables forming printer controller 40 which may be integrated on the microcomputer or comprises separate integrated circuit components.
• a microcomputer would be programmed to provide the various signals as required in accordance with routine programming skills.
• each printer driver IC (DR1...DR24) and with reference now to Fig. 6, there may be provided associated with each recording element an exposure counter 200 into which data lines D0-7 are input.
• LOADb the count value established by the image data signals on lines D0-7 are stored in a first register in the counter.
• the count value in the first register is compared with a count in a second register that counts clock signals input on the line DCLK.
• the control of transmission of data through the drivers and latching thereof is controlled by the signals DCLK, SETb and LOADb signals as is well known.
• the high-level strobe signal HLSTR is shown to have a duty cycle represented by a delay subsequent to ending of the data transfer period.
• the period represented by the data transfer signal is of sufficient duration to allo w data to be serially transferred to all the count registers on the print head so that within each count register there is established a count number representing the time for recording the respective image data by that recording element during that particular line period.
• a delay is established between the start of the high-level strobe signal HLSTR and the end of the data transfer period. The length of this delay establishes a duty cycle for the exposure period.
• Several hundred low-level strobe pulses may be present within a single high-level strobe signal HLSTR at the 90 percent duty cycle for the high-level strobe signal.
• the duty cycle for the high-level strobe signal HLSTR during recording using the first triad of color patches reduces linearly as illustrated in Fig. 11 and thus the number of low-level strobe signals present within a single high-level strobe signal linearly decreases with the line number since the period and duty cycle for the low-level strobe signal LLSTR is not changed from line to line in this first embodiment.
• the duty cycle for the high-level strobe signal HLSTR is 0 percent for lines 1 through 922.
• the duty cycle for the high-level strobe signal HLSTR increases linearly and thus the number of low-level strobe signals LLSTR present within a single high-level strobe signal HSTR increases linearly with the line number again because the period and duty cycle for the low-level strobe signals LLSTR in this embodiment is not changed from line to line.
• Fig. 7B an example is provided of the signals during recording in the overlap region when recording the second triad of color patches.
• the data input to the exposure counter for this recording element is identical to that input for this line number and color patch when the first triad of color patches was printed.
• the duration of the high-level strobe signal HLSTR is essentially complementary to the duration of the high-level strobe signal used during recording of the same line number and color patch during recording of the first triad of color patches.
• complementary it is meant that where the duty cycle for a particular recording line is 90 - x for the high-level strobe signal during recording using a color patch, for example cyan, in the first triad of color patches the duty cycle will be x for the high-level strobe signal using the counterpart color patch, cyan, in the second triad of color patches.
• the heater on time will be relatively short due to the ANDing logic operation.
• Fig. 15 there are shown three pixels recorded by the printhead on the receiver sheet using the invention and for printing during the enlarged recording mode wherein two triads of color patches are used.
• the pixel to be formed at each of the three locations is to be formed in the cyan color.
• the pixels to be formed will each be of the same density, say for example 128 of a possible selectable range of 0 through 255.
• the printhead is capable of printing gray levels dependent upon the data to be recorded in a particular one of the gray levels from 0 through 255.
• Pixel number 300 will be recorded using the cyan color patch of the first triad only, i.e. this pixel is in the region of lines 1 through 922.
• the printhead recording element for recording this pixel will be driven with a predetermined high-level strobe signal HLSTR having a duty cycle of 90 percent.
• HLSTR high-level strobe signal
• LLSTR low-level strobe signals having a duty cycle of sixty percent.
• the duration of enablement of energy for recording pixel 300 will be dependent upon the density for recording the particular color at that location.
• the second triad of color patches will not be used at all for recording pixel 300.
• the printhead recording element for recording this pixel will be actuated for recording a portion of this pixel using the cyan color patch of the first triad of color patches and then subsequently used for recording the next portion of this pixel using the cyan color patch of the second triad of color patches.
• the density recorded for each portion of this pixel will be dependent upon the line number.
• the portion in terms of density of the pixel recorded by the color patch of the first triad will be greater for pixels on line numbers closer to 923 and thus there will be less dye transfened for such pixels from a color patch in the second triad of color patches.
• the portion in terms of density of the pixel recorded by the color patch of the first triad will be less for pixels on line numbers closer to 1006 as there will be more dye transfened for such pixels from a same color of color patch in the second triad of color patches.
• the high-level strobe signal changes from line to line for both the recording using the first triad of color patches and for recording using the second triad of color patches.
• the number of low-level strobe signals for recording the pixel 305 will be about the same as that for recording the pixel 300 except that the recording will be done at two different times using the two different color patches to provide the same density result of 128.
• a pixel such as pixel 310 of Fig. 15 in the non-overlap area of lines 1007 through 2101 of the receiver sheet this pixel will be recorded entirely using the cyan color patch of the second triad of color patches without any contribution at all from a color patch of the first triad of color patches.
• the overlap region has purposefully been defined as not passing through the center of the print.
• the overlap region is approximately slightly more than one-quarter of an inch long in the direction of the advancement of the receiver sheet.
• the low-level strobe signal LLSTR is modified on a line by line basis linearly so that in the non-overlap area the duty cycle for the low- level strobe signal LLSTR is sixty percent duty cycle, see Fig.
• This low-level strobe signal duty cycle decreases to zero at line 1006 during recording of the image using the first triad of color patches. Illustrated in Fig. 14 is the low-level strobe signal of the duty cycle of 30 percent whereas in Fig. 13 the low-level strobe signal has a duty cycle of sixty percent which is the case in the non-overlap area.
• the low-level strobe signal LLSTR starts out at zero percent duty cycle for line 923 and linearly increases from zero percent to sixty percent duty cycle at line 1006.
• the number of low-level strobe signals in a high-level strobe signal of a predetemiined remains the same for the embodiment of Figs. 12-14 since the duration of the on time of the heater element is related to the duty cycle of the low-level strobe signal multiplied by the number of such signals.
• density printed using each color patch from the two triads of color patches had adjustment of contribution in the overlap region by using changes in the duty cycles of the strobe signals; i.e. either the high-level strobe signal or the low-level strobe signal.
• adjustment of contribution is made through adjustment of the image data sent to the print head.
• Such setting can be accomplished by adjustment of conversion coefficients from table 102 or from the input of various corcection data input into the converter 103.
• the settings for such internal gradation converter 103 will be the same as for recording using the first triad of color patches, wherein the only difference is that the image data PDATA is likely to vary in accordance with the image.
• lines 923 through 1006 a different lookup table of values is provided to modify the image data in accordance with line number of the line being recorded.
• the density of the image data will be changed with line numbers so that for gray level pixels recorded using the first triad of color patches, and such pixels being located closer to line 923, the amount of contribution by the first set of color patches to record that pixel will be greater and the contribution by the second set of color patches will be less.
• the density of the images is adjusted for use of values from a lookup table so that the contribution to density of the resulting printed pixel is greater for the second triad of color patches for pixels that are closer to line 1006.
• the transparent overcoat forming a part of the first quad of color patches using the printhead and having all the recording elements thereof be at a constant heating level so that the transparent patch of the first quad is applied during recording lines 1 through 922 when the transparent patch is between the printhead and the receiver sheet. Only the first 922 lines are employed in recording using this first transparent patch since the remainder of the pixels in the overlap region need to be completed in their recording or printing using the second quad of color patches. After recording the complete image using the three color dye patches of the second quad the second transparent patch and forming a part of the second quad set of color patches is then used to be applied over lines 923 through 2101.
• step 350 data and strobe signals are output to the printhead and in step 360 the data for a line n is printed. After printing of this line the receiver and donor web are advanced by one line increment and the line counter is incremented as well.
• steps 330,340,350,360 and 370 of repeated until the line number count n N for that color patch.
• the next color patch is advanced to the printhead, step 375.
• a determination is made as to whether or not the yellow, magenta, cyan and optionally the transparent patch are completed for that triad or quad of color patches.
• step 385 a determination is made in step 385 as to whether or not printing with the second color patch set has been completed. If not, advancement is made of the second color patch set for printing, step 387.
• step 390 printing stops for that print.
• the printing of the two sub- images to form a composite image has the pixels in the overlap region formed by combining deposition of material from the color patches of each triad or quad of color patches.
• a gray level pixel in the overlap region is formed by material from both triads or both quads.
• the high-level strobe signal HLSTR and/or the low-level strobe signal LLSTR are modified on a changing line by line basis as described herein to adjust the contributions of the transference of colorants from each of the triads or quads to each gray level pixel.
• a gray level pixel is defined to have a density that can be made variable in accordance with image data to more than two levels of density including no density.
• the receiver sheet employed herein may be a discrete sheet of predetermined size or a continuous receiver sheet in which the composite image formed by the two sub- images are formed.
• the receiver sheet may have microperfs to define an image area so that the composite image is formed within the boundary defined by the microperfs and optionally the side edges of the receiver sheet.
• the microperfs may then be used to facilitate removal of the unprinted border of the receiver sheet from the printed portion having the composite image.

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• 2003
  • 2003-11-06 US US10/702,896 patent/US6961075B2/en not_active Expired - Lifetime
• 2004
  • 2004-10-21 DE DE602004013821T patent/DE602004013821D1/de not_active Expired - Lifetime
  • 2004-10-21 JP JP2006539528A patent/JP2007510562A/ja active Pending
  • 2004-10-21 EP EP04795812A patent/EP1682353B1/en not_active Expired - Lifetime
  • 2004-10-21 WO PCT/US2004/034702 patent/WO2005047004A2/en not_active Ceased

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