EP0648608A1 - Compensation de résistance parasite pour imprimantes thermiques - Google Patents

Compensation de résistance parasite pour imprimantes thermiques Download PDF

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Publication number
EP0648608A1
EP0648608A1 EP94114525A EP94114525A EP0648608A1 EP 0648608 A1 EP0648608 A1 EP 0648608A1 EP 94114525 A EP94114525 A EP 94114525A EP 94114525 A EP94114525 A EP 94114525A EP 0648608 A1 EP0648608 A1 EP 0648608A1
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EP
European Patent Office
Prior art keywords
resistive heat
heat elements
voltage
level
power supply
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94114525A
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German (de)
English (en)
Inventor
Young C/O Eastman Kodak Company No
David Louis C/O Eastman Kodak Company Jeanmaire
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Eastman Kodak Co
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Eastman Kodak Co
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Filing date
Publication date
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Publication of EP0648608A1 publication Critical patent/EP0648608A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • B41J2/36—Print density control

Definitions

  • the invention relates to thermal printers and more particularly to circuitry for supplying energy to thermal printhead resistive heat elements.
  • a thermal printhead utilizes a row of closely spaced resistive heat generating elements which are selectively energized to record data in hard copy form.
  • the data may comprise stored digital information related to text, bar codes, pictorial, or graphical images.
  • the thermal printhead resistive heat elements receive energy from a power supply through driver circuits in response to the stored digital information.
  • the heat from each energized element may be applied directly to thermal sensitive material or may be applied to a dye coated web to cause transfer of the dye by diffusion to paper or other receiver material.
  • each resistive heat element is a function of a number of factors including the voltage applied to the element, the thermal state of the element and the thermal states of the surrounding elements.
  • the structure of the system is such that unwanted voltage drops occur between the power supply and the resistive heat elements.
  • This "parasitic resistance" voltage drop varies as a function of the number of simultaneously energized resistive elements. If a large number of elements are energized, the effective voltage across the resistive heat elements decreases, and correspondingly, the optical density of the printed image decreases. Thus, the optical density of a single pixel becomes dependent on the number of heat elements energized and the corresponding system parasitic resistance.
  • U.S. Patent No. 4,736,089 (issued to Victor D. Hair on April 5, 1988) discloses a switching regulator for a thermal printhead in which the printhead temperature is sensed by a voltage generating diode incorporated in the printhead. The diode voltage is fed back to control the reference voltage of a switching regulator power supply that provides power to the printhead.
  • U.S. Patent No. 4,724,336 (issued to Takashu Ichikawa et al. on February 9, 1988) discloses a power circuit for a thermal printhead in which the head resistance values are stored and the reference voltage of printhead power supply is selected from memory for each printhead element resistance. In this way, compensation is provided for the variations in the individual printhead element resistances. The arrangement, however, requires that the value of individual printhead resistances be measured and does not compensate for voltage or temperature variations.
  • U.S. Patent No. 4,531,134 (issued to Frank J. Horlander on July 23, 1985) discloses a regulated voltage circuit for a thermal printhead in which the voltage at one electrode of each resistive heat element is monitored and the lowest voltage is fed back to determine the current in a resistive ribbon printer via a differential amplifier control circuit. In this way, the energy to the resistive heat elements is maintained above a predetermined minimum.
  • U.S. Patent No. 4,434,356 (issued to Timothy P. Craig et al. on February 28, 1984) discloses a current drive circuit for a thermal ribbon printer in which the voltage at each ribbon resistance is monitored and used as a control input to a voltage regulator circuit that produces a head resistance drive voltage.
  • thermal printheads incorporate driver and other circuitry that control printhead operation so that it is difficult to obtain access to the electrodes of individual printhead resistive heating elements. It is relatively easy, however, to determine the voltage at the terminals of the printhead connectors. But the voltage across the printhead includes parasitic drops across power supply lines, interconnections and other wiring internal to the printhead. These parasitic voltage drops are proportional to the number of resistive heat elements turned on for a print line. As a result, the parasitic voltage drops vary considerably as the number of selected heating elements changes. The varying resistive heat element voltage produces noticeable variations in the density of the imprinted picture elements or pixels.
  • U.S. Patent No. 4,774,528 (issued to Nobuhisa Kato on September 27, 1988) discloses thermal recording apparatus in which the black density of pixels to be recorded by thermal recording elements are compared to reference density levels.
  • a counter accumulates a value representing the number of pixels having density levels in certain ranges as a result of the comparison. The counter value is used to adjust the pulse width of energizing pulses to compensate for voltage fluctuations at the printhead resistive heat elements due to the number of recording elements energized at one time. Adjustment of energizing pulse widths, however, is complex and does not yield sufficiently precise energy control to compensate for resistive heat element voltage variations.
  • the number of selected resistive heat elements is sensed by generating a signal representative of the current coupled from the voltage source to the printhead, or by counting the sequence of data bits applied to the printhead and forming a signal representative of the number of selected resistive heat elements in response to the data bit count.
  • the voltage coupled to the printhead is modified in response to the number of selected resistive heat elements to maintain the prescribed voltage across the selected resistive heat elements substantially constant and independent of the number of selected resistive heat elements.
  • U.S. Patent No. 4,442,342 (issued to Shigeo Yoneda on April 10, 1984) discloses a voltage-to-frequency converter with an output frequency determined by the value of the voltage applied to the print head. The print head enabling voltage is applied to the print head until a count characteristic of the frequency output of the voltage-to-frequency converter reaches a predetermined value.
  • a fixed voltage is applied across the printhead.
  • the structure of the system is such that unwanted voltage drops occur between the power supply and the resistive heat elements, such as for example by parasitic resistance voltage drop.
  • Parasitic resistance voltage drop varies as a function of the number of simultaneously energized resistive heat elements. If a large number of resistive heat elements are energized, the effective voltage across the resistive heat elements decreases.
  • the optical density of the printed image drops. The optical density of a single pixel becomes dependent on the number of resistive heat elements energized and on the corresponding system parasitic resistance. These density variations due to the system parasitic resistance produce significant image artifacts. Excessive loading of the power supply due to a large number of resistive heat elements being energized simultaneously causes the effective voltage drop across the resistive heat element to fluctuate during the energizing period, creating an additional image artifact.
  • the present invention is directed to thermal printing apparatus in which a thermal printhead receives electrical current from a voltage source and directs the current to selected ones of a plurality of resistive heat elements under control of a sequence of data bits.
  • the duration of the energizing current is controlled by an enable pulse.
  • the level of the supply voltage to the print head is compared to a reference value, and the difference is used to control the duration of the enable pulse in response to variations in the supply voltage.
  • the thermal energy supplied by the selected resistive heat elements remains substantially constant and independent of the number of selected resistive heat elements.
  • real time parasitic resistance compensation is achieved by continuously monitoring the power supply voltage and adding a compensation energy pulse to the main heat element energizing pulse using the accumulated difference between a reference normal operating voltage and the pixel power supply voltage over the entire energizing time period.
  • a preset reference voltage determined solely by the average heat element resistance and the desired maximum density level, and by varying the energy pulse width with the accumulated power difference of the voltages over the entire pixel energizing time period, the desired energy level can be achieved independent of the incident power supply level shift and the fluctuation. Since the minimum parasitic resistance effect would occur when only one heat element in the head is energized, the main element energizing pulse used in the scheme is predeterminable to produce desired maximum density when one heat element is energized with normal operating head voltage.
  • a thermal printer in an illustrative embodiment of the invention, includes a printhead comprising first and second terminals and a plurality of resistive heat elements. Each resistive heat element has first and second electrodes.
  • a voltage source having positive and negative terminals supplies current to the printhead.
  • a bus couples the positive terminal of the voltage source to the first terminal of the printhead.
  • the first terminal of the printhead is coupled to the first electrode of each resistive heat element.
  • Data supplied to printhead selectively couples the second electrodes of the resistive heat elements to the second terminal of the printhead for a duration of time equal to the duration of an enable pulse, which duration is adjusted in accordance with the difference between the mathematical squares of the level of a predetermined reference voltage level and the level of the voltage source.
  • Thermal printer apparatus 10 comprises a rotatable drum 12, a receiver member 14 in the form of a sheet, drive mechanisms 22 and 24, a carrier member which may be a sheet, but preferably is in the form of a web 16, a supply roller 20, a take-up roller 18, a thermal printhead 26 and a printhead control circuit 28.
  • the printhead control circuit comprises a power supply, an image data source and a control pulse generator.
  • Drive mechanism 22 comprises a motor (not shown) mechanically coupled to take-up roller 18.
  • Carrier member 16 is disposed between supply roller 20 and take-up roller 18 and passes between printhead 26 and receiver member 14.
  • Drive mechanism 24 comprises a motor (not shown) that is mechanically coupled to rotatable drum 12. Receiver member 14 is secured to drum 12. Thermal printhead 26 comprises a plurality of resistive heat elements. Printhead control circuit 28 is electrically coupled via conductors 30 to thermal printhead 26.
  • Printhead 26 is pivotally mounted and its resistive heat elements normally press against carrier member web 16.
  • Drive mechanisms 22 and 24 cause take-up roller 18 and drum 12 to rotate and thereby advance carrier member web 16 and receiver member 14.
  • the resistive heat elements of printhead 26 are selectively energized in accordance with data from printhead control circuit 28 as drum 12 and take-up roller 18 are continuously advanced.
  • the image defined by the data from printhead control circuit 28 is placed on receiver member 14.
  • the arrangement of Figure 1 is similar to that described and illustrated in U.S. Patent No. 4,786,917 (issued to Edward A. Hauschild et al. on November 22, 1988).
  • Figure 2 comprises printhead 26, power supply 32, a power supply bus 34, a power return bus 36, and power supply connection terminals 38 and 40.
  • Printhead 26 comprises a power supply line 42, resistive heat elements 44-1, 44-2,..., 44-N, switches 46-1, 46-2,..., 46-N, a power return line 48, latches 50-1, 50-2,..., 50-N, an N-stage shift register 52, an enable line 54 from an enable pulse generator 55, a latch line 56, a data line 58 and a clock line 60.
  • the control terminals of switches 46-1 through 46-N are coupled to the output terminals of latches 50-1 through 50-N, respectively.
  • the input terminals of latches 50-1 through 50-N are coupled to successive stages of shift register 52.
  • the latch terminals of latches 50-1 through 50-N are coupled to latch line 56 and the enable terminals of latches 50-1 through 50-N are coupled to enable line 54.
  • a first input of shift register 52 is coupled to data line 58 and a second input of shift register 52 is coupled to clock line 60.
  • the data codes are used to form a sequence of data bits which are transferred from printhead control circuit 28 to printhead 26 to energize printhead heat elements 44-1 through 44-N.
  • Each printhead resistive heat element is energized by the number of data bits needed to produce the print density required at the corresponding pixel.
  • the number of data bits may vary from zero to 255 for an 8-bit data code.
  • the data bits DATA are serially shifted into shift register 52 of Figure 2 via data line 58.
  • a clock source (not shown) in printhead control circuit 28 of a design well known in the art supplies signals CLK to shift register 52 on line 60 to control the shifting of the data bits into the shift register at a predetermined rate.
  • the N-data bits are received by shift register 52, they are transferred to latches 50-1 through 50-N by latch pulse LA from line 56 in a manner well known in the art.
  • Switches 46-1 through 46-N are closed responsive to the data bits in the corresponding latches and an enable pulse EN on the enable terminals of latches 50-1 through 50-N so that resistive heat elements 44-1 through 44-N selectively receive current from power line 42 for the duration of enable pulse EN.
  • Shift register 52 successively receives 256 sets of data bits which control printhead resistive heat elements 44-1 through 44-N so that the print density at each pixel of a print line corresponds to the data code stored in printhead control circuit 28 for that pixel and the duration of enable pulse EN.
  • latch 50-1 controls switch 46-1 so that a number of predetermined width pulses corresponding to the data code in printhead control circuit 28 are coupled to the control terminal of switch 46-1.
  • Switch 46-1 is closed in response to enable pulse EN and the state of latch 50-1.
  • a predetermined width enable pulse EN closes switch 46-1.
  • resistive heat element 44-1 is energized by power supply 32 in accordance with the density defined by the image pixel data code in printhead control circuit 28 and the width of enable pulse EN.
  • latches 50-2 through 50-N control the operations of switches 46-2 through 46-N to determine the heat generated by resistive heat elements 44-2 through 44-N, respectively.
  • pulse waveforms (volts) as a function of time (microseconds) illustrating the data bits supplied to shift register 52, the clock signals used to insert the data bits into shift register 52, the latch pulse used to insert the data bits into latches 50-1 through 50-N, and the enable pulse used to transfer the data bits in the latches to control switches 46-1 through 46-N, respectively.
  • a waveform 62 shows clock pulses CLK which control the insertion of data bits into shift register 52.
  • a waveform 63 shows a portion of the data bit stream DATA on line 58 corresponding to the data bits for one of the 256 sets of data bits transferred to shift register 52 for a print line.
  • a waveform 64 shows latch pulse used to insert the set of data bits shown in waveform 63 into latches 50-1 through 50-N.
  • a waveform 65 shows an enable pulse EN that transfers the data bits in latches 50-1 through 50-N to the control inputs of switches 46-1 through 46-N.
  • a latch pulse occurs at the end of the transfer of each set of data bits into shift register 52.
  • the data stream DATA on line 58 shown in waveform 63 is shifted into shift register 52 by clock signals CLK shown in waveform 62 that each data bit is positioned to control a specified resistive heat element.
  • a data bit may be a ZERO (i.e., LOW level) bit or a ONE (i.e., HIGH level) bit.
  • Heat elements 44-1 through 44-N are energized by data bits that are ONEs. For example, the data bit labeled 1 of waveform 63 (a ONE data bit) is positioned so that it is transferred to latch 50-1 when the N-data bit set for a print line are aligned in shift register 52.
  • the data bit labeled N (a ONE data bit) is positioned so that it is transferred to latch 50-N.
  • a latch pulse LA on line 56 a one data bit is transferred from shift register 52 into latch 50-1 and the ONE data bit N is transferred into latch 50-N.
  • Enable pulse EN then provides a predetermined width pulse to the control input of each switch of switches 46-1 through 46-N for each latch that stores a one data bit.
  • the data bits in latches 50-1 and 50-N cause predetermined width pulses to be applied to switches 46-1 and 46-N so that the heat energy in the corresponding resistive heat elements 44-1 and 44-N are precisely controlled.
  • each print line varies in accordance with the data supplied to printhead 26.
  • all, some, or none of resistive heat elements 44-1 through 44-N may be selected concurrently.
  • Each selected resistive heat element is coupled to power supply 32 through power supply bus 34, connection terminal 38, power supply line 42, power return line 48, connection terminal 40, and power return bus 36.
  • a fixed voltage is applied across the printhead.
  • the structure of the system is such that unwanted voltage drops occur between the power supply and the resistive heat elements, such as for example by parasitic voltage drop.
  • Parasitic voltage drop varies as a function of the number of simultaneously energized resistive heat elements. If a large number of resistive heat elements are energized, the effective voltage across the resistive heat elements decreases.
  • the optical density of the printed image drops. The optical density of a single pixel becomes dependent on the number of resistive heat elements energized and on the corresponding system parasitic resistance. These density variations due to the system parasitic resistance produce significant image artifacts. Excessive loading of the power supply due to a large number of resistive heat elements being energized simultaneously causes the effective voltage drop across the resistive heat element to fluctuate during the energizing period, creating an additional image artifact.
  • FIG. 4 there is shown a graph that illustrates the voltage variations resulting from the aforementioned "parasitic resistance" within printhead 26.
  • line 66 is a plot of the desired voltage (volts) at the output of power supply 32 in volts as a function of the printhead current in amperes
  • line 68 is a plot of the actual voltage (volts) at the output of power supply 32 in volts as a function of the printhead current (amperes).
  • Line 66 is horizontal corresponding to a constant voltage over the full range of the printhead current.
  • Line 68 slopes downward as the printhead current increases due to the voltage drop in the "parasitic resistance". Consequently, there may be significant variation in the density of successive print lines.
  • a print line that results from a relatively small number of selected resistive heat elements has densities corresponding to a higher resistive heat element voltage than a print line resulting from a large number of selected resistive heat elements.
  • Such variations in print density are generally not noticeable in text-type prints, where only black and white pixels are used.
  • density variations greater than one percent may be discernible.
  • FIG. 5 there is shown a block diagram of a voltage compensated thermal printhead power supply arrangement in accordance with the present invention.
  • the voltage compensated thermal printhead power supply arrangement of Figure 5 comprises printhead 26, power supply 32, and a voltage compensator 70.
  • Printhead 26, power supply 32, and enable pulse generator 55 are the same as shown in Figure 2.
  • Printhead 26 is connected as described with respect to Figure 2.
  • Power supply bus 34 in Figure 5 is connected between a positive output of power supply 32 and connection terminal 38.
  • Power return bus 36 in Figure 5 is connected between a negative output of power supply 32 and connection terminal 40 via bus 36.
  • Voltage compensator 70 is adapted to sense the voltage supplied from power source 32 and to modify the width of enable pulse EN so that the energy supplied to each printhead resistive heat element is maintained at a constant level substantially independent of the number of selected resistive heat elements. In this way, the aforementioned "parasitic resistance" voltage drop is offset to prevent variations of print density.
  • Thermal printers according to the present invention incorporate a real time compensation method for the system parasitic resistance and the power supply loading.
  • the compensation is achieved by continuously monitoring the power supply voltage and adding a compensation energy pulse of adjustable duration to the main resistive heat element enable pulse in accordance with the accumulated difference between the square of the a reference voltage V R and the square of the printhead power supply voltage V S over the entire printhead energizing time period.
  • Reference voltage V R is predetermined as a function of the average resistance of the resistive heat elements and the desired maximum printed density level.
  • FIG. 6 there is shown a graph that illustrates the enable pulse of Figure 5.
  • Enable pulse generator 55 of Figure 5 produces a main enable pulse illustrated in Figure 6 as extending from time t1 to time t2, for time period t2-t1. Time period t2-t1 is fixed.
  • a compensation enable pulse of adjustable duration is added to the main enable pulse by voltage compensator 70 of Figure 5.
  • the compensation enable pulse starts at time t2 of Figure 6, and extends to time t3 if the main power supply voltage V S on power supply bus 34 is equal to the reference value V R applied to voltage compensator 70.
  • the duration of the compensation enable pulse is automatically adjusted toward time t2 or time t4 if the main power supply voltage V S differs from the reference value V R , as will now be explained with reference to Figure 7.
  • FIG. 7 there is shown a schematic and block diagram of one type of voltage compensator 70 arrangement of Figure 5 in accordance with the invention.
  • the inputs to voltage compensator 70 include main power supply voltage V S , reference value V R , and the main enable pulse.
  • a multiplier/comparator 74 takes the difference between the squares of main power supply voltage V S and reference value V R , and inputs the difference value to inverting inputs of a voltage-to-frequency converter 76, such as for example, a voltage controlled oscillator.
  • the frequency of voltage-to-frequency converter 76 increases with the increasing input voltage from multiplier/comparator 74, which indicates a smaller number of heat elements are turned on simultaneously.
  • the system experiences minimum parasitic resistance power supply loading, and a minimum width compensation energy pulse is required.
  • the frequency output from voltage-to-frequency converter 76 is logically ANDed with the inverted enable pulse and input to an UP count enable 78.
  • the output of UP count enable 78 is input to an UP/DOWN counter 80, which has been cleared to ZERO at the beginning of every main enable pulse.
  • Both voltage-to-frequency converter 76 and UP/DOWN counter 80 are synchronized with a clock generator 82.
  • a DOWN count enable 84 activates UP/DOWN counter 80 to supply compensation energy pulse to the thermal head.
  • the initial value of the DOWN counter is the accumulated sum of the UP counter.
  • the frequency output of voltage-to-frequency converter 76 is counted up during the main enable period, and the accumulated count of the frequency is used as the initial value of the Down Counter for compensation pulse width, a lower frequency output is required when smaller number of heat elements are turned on.
  • the sum of the count accumulated during the main enable period should be counted down before the next main enable pulse is asserted. Therefore, the relative run rates of UP count enable 78 and DOWN count enable 84 can be calculated from the maximum required compensation pulse width to keep the dead time between the enable pulses to a minimum to thereby decrease printing line times.
  • the maximum frequency output of voltage-to-frequency converter 76 used in the preferred embodiment of the present invention is 1/4 the input clock frequency.
  • a divide-by-two circuit 86 provides the necessary clock frequency to voltage-to-frequency converter 76 to ensure the UP counter runs at 1/8 of the frequency of the DOWN counter; as this is the relative run rates of UP counter in the illustrated embodiment.
  • the resolution step of the compensation pulse width is determined by the frequency of clock generator 82 and the number of resolution steps of the UP/DOWN counter used.
  • the circuit of the preferred embodiment has 256 steps of resolution, and requires a 16 MHz system clock for a 5msec. print line time.
  • a compensation energy pulse of adjustable duration according to the accumulated sum of the differences is then added to the main resistive heat element enable pulse.
  • the modified enable pulse is then sent to the thermal print head.
  • the duration of enable pulse 54 of Figure 5 is adjusted to account for changes main power supply voltage V S due to the varying number of selected resistive heat elements. In this way, the total energy applied to the selected resistive heat elements is maintained at a predetermined value.

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EP94114525A 1993-10-14 1994-09-15 Compensation de résistance parasite pour imprimantes thermiques Withdrawn EP0648608A1 (fr)

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US13731493A 1993-10-14 1993-10-14
US137314 1993-10-14

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017001639A1 (fr) * 2015-06-30 2017-01-05 Ingenico Group Procédé de gestion d'une imprimante thermique, dispositif et programme correspondant

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4442342A (en) * 1981-05-01 1984-04-10 Sharp Kabushiki Kaisha Thermal printer with print density control
EP0202922A2 (fr) * 1985-05-24 1986-11-26 Ncr Canada Ltd - Ncr Canada Ltee Système d'impression thermique
US4774528A (en) * 1986-04-30 1988-09-27 Fuji Xerox Co., Ltd. Thermal recording apparatus capable of gradation recording
US5053790A (en) * 1990-07-02 1991-10-01 Eastman Kodak Company Parasitic resistance compensation for thermal printers

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4442342A (en) * 1981-05-01 1984-04-10 Sharp Kabushiki Kaisha Thermal printer with print density control
EP0202922A2 (fr) * 1985-05-24 1986-11-26 Ncr Canada Ltd - Ncr Canada Ltee Système d'impression thermique
US4774528A (en) * 1986-04-30 1988-09-27 Fuji Xerox Co., Ltd. Thermal recording apparatus capable of gradation recording
US5053790A (en) * 1990-07-02 1991-10-01 Eastman Kodak Company Parasitic resistance compensation for thermal printers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017001639A1 (fr) * 2015-06-30 2017-01-05 Ingenico Group Procédé de gestion d'une imprimante thermique, dispositif et programme correspondant
FR3038255A1 (fr) * 2015-06-30 2017-01-06 Ingenico Group Procede de gestion d'une imprimante thermique, dispositif et programme correspondant
US10328716B2 (en) 2015-06-30 2019-06-25 Ingenico Group Method for managing a thermal printer, corresponding device and program

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