JP2011062947A - Thermal transfer printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer printing device enabling making a high-resolution printing compatible with a high-speed printing by way of using a pixel extended in the sub-scanning direction. <P>SOLUTION: The thermal transfer printing device includes a thermal head consisting of a plurality of heating elements arranged in the main scanning direction, an ink ribbon for holding an ink dissolved by overheating of the heating element, a conveying means for conveying a printing medium in the sub-scanning direction, and a control means for controlling the thermal head and the conveying means. The control means perform the individual controlling of a voltage applying period per unit pixel for each heating element of the thermal head together with the conveying speed in the sub-scanning direction of the printing medium with the conveying means in accordance with a plurality of different printing modes with the first printing mode for performing the printing by making the size for one element of the heating element composing the thermal head as a pixel unit and the second printing mode for performing the printing by making the magnitude obtained by extending one element of the heating elements in the sub-scanning direction as a pixel unit. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermal transfer printing apparatus that directly or indirectly thermally transfers and prints information such as images and characters on a recording medium such as paper or plastic, and in particular, for resolution printing and image printing for printing characters or symbols. The present invention relates to a thermal transfer printing apparatus capable of gradation printing.

  As a thermal transfer printing apparatus, black or color ink applied to an ink ribbon is dissolved or sublimated (herein simply referred to as “dissolving”) by selective heating of a thermal head composed of a plurality of heating elements and dissolved. Devices that print necessary characters or symbols and images on a print medium by directly transferring the ink onto a print medium such as paper or plastic are widely known.

  Furthermore, as another printing method by such thermal transfer, a card such as a credit card, a cash card, a license card, an ID card, etc., in which a data recording medium such as a magnetic stripe or an IC chip is provided on a card made of plastic or thick paper As a technique for printing images such as graphics, characters and symbols on a recording medium, the image is temporarily printed on a film-like intermediate transfer medium (referred to as “primary transfer” in the present application), and this primary transferred image There is also known a transfer type card printing apparatus that finally transfers a card onto a card-like recording medium (referred to as “secondary transfer” in the present application) (see, for example, Patent Document 1).

  In any of the above-described thermal transfer printing apparatuses, for example, in the case of a thermal transfer printing apparatus capable of printing at 600 dpi (dot per inch), the selective heating element of the thermal head in which about 24 heating elements are arranged per millimeter in the main scanning direction. Due to overheating, it is transferred directly or indirectly onto the print medium. In the conventional ink-dissolving thermal transfer apparatus, it is difficult to adjust the amount of ink transferred to the printing medium according to the amount of heat generated by each thermal head heating element. If necessary, the dot density (the number of dots per unit area) on the print medium is adjusted (see, for example, Patent Document 2).

  That is, in such a conventional thermal transfer printing apparatus, when printing a binary image such as a character or a symbol, for example, high resolution printing with a smaller pixel pitch is performed and an image such as a photograph (tone image) is printed. In this case, gradation printing is performed by increasing the pixel pitch.

Japanese Patent No. 3737037 Japanese Patent No. 3130096

  However, in the case of card printing, for example, an image is often printed together with characters and symbols on the same print medium. In the case of printing characters and symbols, a certain degree of resolution is required. However, since gradation is more important than resolution in gradation image printing, it is not always necessary to print at high resolution as described above. However, when it is necessary to express fine portions such as human hair, it is required to print at a high resolution by reducing the pixel pitch.

  Furthermore, when printing is performed with a large pixel pitch, the printing speed can theoretically be increased. However, density unevenness in gradation printing must be avoided.

  For this reason, the present invention is a thermal transfer apparatus capable of high-resolution printing for character or symbol printing and gradation printing for image printing, for example, and can achieve both high-resolution printing and high-speed printing. An object is to provide an apparatus.

  Therefore, the present invention transports a print head in the sub-scanning direction, a thermal head composed of a plurality of heating elements arranged in the main scanning direction, an ink ribbon that holds ink that is thermally dissolved by overheating of the heating elements, and the printing medium. And a control unit that controls the thermal head and the transport unit, and the control unit prints the size of one heating element constituting the thermal head as a pixel unit. Corresponding to a plurality of different printing modes, a first printing mode and a second printing mode in which a size obtained by extending one element of the heating element in the sub-scanning direction is used as a pixel unit, The voltage application time per unit pixel for each heating element of the thermal head is individually controlled together with the conveyance speed of the print medium in the sub-scanning direction. There is provided a copy printing device.

  As described above, in the thermal transfer printing apparatus of the present invention, the voltage application time per unit pixel for each heating element of the thermal head is set in accordance with the conveyance speed in the sub-scanning direction of the printing medium according to the printing mode. Since it is controlled individually, high-resolution printing and high-speed printing are possible.

  Here, in the first printing mode, the control unit controls the conveyance speed of the printing medium by the conveyance unit to a first conveyance speed, and in the second printing mode, the conveyance unit The transport speed of the print medium is controlled to a second transport speed that is faster than the first transport speed. Then, when the transport speed of the print medium is controlled to the second transport speed in the second print mode, the drive time of the thermal head is made to correspond to the transport speed of the print medium and the thermal head is moved to the thermal head. The voltage application time is lengthened.

  In the thermal transfer printing apparatus, when printing characters on the printing medium, printing is performed in the first printing mode. When printing an image on the printing medium, the printing is performed according to the second printing mode. Printing is performed.

  Further, the thermal transfer printing apparatus is also compatible with color printing. In this case, the ink ribbon has at least one color band and one single color band (colorless color or a color system different from the color band). And a plurality of different bands are formed in a frame sequential manner, and the control unit is configured to perform the first printing mode in monochrome printing using only the monochrome band and color printing using the color band. And the transfer speed of the print medium by the transfer means and the voltage application time to the thermal head in the second print mode are changed.

  In the thermal transfer printing apparatus, the thermal head primarily transfers characters or images to a film-like intermediate transfer medium, and presses the primary-transferred film-like intermediate transfer medium against the print medium, thereby The present invention is also applicable to a thermal transfer printing apparatus that prints an image on the printing medium.

  As described above, in the thermal transfer printing apparatus according to the present invention, the first print mode in which the size of one heating element constituting the thermal head is printed in units of pixels and one heating element is arranged in the sub-scanning direction. Corresponding to a plurality of different printing modes of the second printing mode for printing in a pixel unit with the size extended to the pixel unit, the voltage for each heating element of the thermal head corresponding to the conveyance speed of the print medium in the sub-scanning direction Since the application time is individually controlled, high resolution printing and high speed printing are possible.

1 is a side view showing a schematic configuration of a card printing apparatus to which a thermal transfer printing apparatus according to an embodiment of the present invention is applied. It is a schematic diagram which shows the outline of the control part of the card printing apparatus to which the thermal transfer printing apparatus which concerns on one Embodiment of this invention is applied. It is a schematic diagram for demonstrating the printing mode in this thermal transfer printing apparatus which concerns on one Embodiment of this invention. FIG. 4 is a schematic diagram showing dot states actually printed in the “high-definition mode” and “intermediate mode” shown in FIG. 3 and the heat generation change of the thermal head. FIG. 4 is a schematic diagram showing one pixel area and voltage application time to a heating element in the “high definition mode” and the “intermediate mode” shown in FIG. 3. It is a side view at the time of performing a hologram process in the card printing apparatus to which the thermal transfer printing apparatus which concerns on one Embodiment of this invention is applied. It is explanatory drawing of a thermal transfer sheet and an intermediate transfer sheet, (A) is a front view which shows typically a thermal transfer sheet, (B) is sectional drawing which shows an intermediate transfer sheet typically.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which an embodiment of the present thermal transfer printing apparatus is applied to a card printing apparatus that often prints images together with character symbols. The present thermal transfer printing apparatus can be applied to an apparatus for directly transferring information such as images and characters on a recording medium such as paper or plastic. A thermal transfer printing apparatus that performs primary transfer of characters or images onto a transfer medium and presses the primary transfer film-like intermediate transfer medium against the print medium, thereby printing the characters or images on the print medium. I decided to.

(Configuration of the present invention)
FIG. 1 is a side view showing a schematic configuration of a card printing apparatus to which a thermal transfer printing apparatus according to an embodiment of the present invention is applied. As shown in FIG. 1, the printing apparatus 1 according to this embodiment includes a third card conveyance path serving as a card conveyance path for recording information on a card C serving as a card-like recording medium in a housing 2 serving as a housing. P ₃ , first card transport path P ₁ that is a card transport path for forming (printing) an image on the card C by a direct transfer method, and temporarily held on an intermediate transfer sheet F as a film-like intermediate transfer medium and a second card transport path P ₂ to be a card transport path for transferring the card C by the indirect transfer method the images are. The second card transport path P ₂ and the third card transport path P ₃ are substantially arranged in a horizontal direction, the first card transport path P ₁ is substantially arranged in a vertical direction. The second card transport path P ₂ are arranged substantially parallel to the third card transport path P ₃ from the third card transport path P ₃ on the upper side (arrow U side in FIG. 1), the conveyance path P ₂ and a second card a third card transport path P ₃ from the first card transport path P ₁ intersect each substantially perpendicularly at an intersection X ₁ and X _2.

On the third card transport path P _3, the card supply unit 3 for feeding the third card transport path P ₃ are separated one by one (the previous magnetically recording processing and printing processing is performed) card C blank , cleaner 4, the first card transport path rotates to invert while nipping the card C as the center of rotation of the intersection X ₂ on the downstream side of the cleaner 4 P ₁ to clean the surface of the blank card C at the downstream side of the card supply section 3 The second reversing unit 5 capable of switching the conveyance path of the card C in the direction orthogonal to the direction, and the magnetism formed on the card surface (back surface) seen on, for example, a credit card on the downstream side of the second reversing unit 5 Information recording sections 8 for performing processing such as data writing and reading to the stripe are provided.

On the first card transport path P ₁ , the card C is rotated or reversed with the intersection point X ₁ as the center of rotation, and the transport path is set to either the first card transport path P _{1 or} the second card transport path P _2. A first inversion unit 6 that selectively switches is arranged. Incidentally, before and after the second reversing unit 5 in the third card transport path on P _3, also between the second inverting section 5 according to the first card transport path P on _a first inverting unit 6, and the first reversing portion 6 for detecting the presence of the card C between the first reversing unit 6 and the horizontal conveyance roller pair 11 (described later) in the second card conveyance path P ₂ . Integrated transmission sensors are respectively provided.

On the first card transport path P _1, on the downstream side of the first reversing unit 6 (the arrow U side in FIG. 1), the thermal transfer ink is used on the card C or an intermediate transfer sheet to be described later according to image information such as images and characters An image forming unit 9 as a printing unit for forming an image is arranged. The image forming unit 9 adopts a thermal transfer printer configuration, and a platen roller 21 that supports the card C when printing on one surface of the card C and a thermal head 20 that is disposed so as to be movable back and forth with respect to the platen roller 21. Have. A thermal transfer sheet (ink ribbon) R is interposed between the platen roller 21 and the thermal head 20.

  As shown in FIG. 7A, the thermal transfer sheet R has a width slightly longer than the length in the longitudinal direction of the card C on the film, for example, Y (yellow), M (magenta), C (cyan), and Bk ( (Black) ink is applied in order, and after Bk (black), the protective layer region T that protects the surface of the card C on which the image is formed has a belt-like shape that is repeated in the surface order. .

  As shown in FIG. 1, the thermal transfer sheet R is supplied from a thermal transfer sheet supply unit 14 obtained by winding the thermal transfer sheet R in a roll shape. The film is wound around a thermal transfer sheet winding unit 15 that is wound into a roll. The thermal transfer sheet supply unit 14 and the thermal transfer sheet take-up unit 15 are disposed at positions on both sides of the thermal head 20, and the central portions are respectively loaded on the spool shafts.

  As shown in FIG. 1, when an image is formed on the card C by indirect transfer, an intermediate transfer sheet F is stretched around the platen roller 21. As shown in FIG. 7B, the intermediate transfer sheet F protects the base film Fa, the back coat layer Fb formed on the back side of the base film Fa, the receiving layer Fe that receives ink, and the surface of the receiving layer Fe. An overcoat layer Fd that is formed on the surface side of the base film Fa, and a release layer Fc that promotes the peeling from the base film Fa by heating the overcoat layer Fd and the receiving layer Fe as a unit. The base film Fa, the release layer Fc, the overcoat layer Fd, and the receiving layer Fe are laminated in this order. The intermediate transfer sheet F is stretched so that the receiving layer Fe side faces the thermal transfer sheet R and the back coat layer Fb side contacts the platen roller 21.

As shown in FIG. 1, on the second card transport path P ₂ is the downstream side of the first inversion section 6 (arrow L side), horizontal conveyor roller pair 11 for conveying the card C horizontally, the image forming unit 9, the image formed on the intermediate transfer sheet F is transferred to the card C. The transfer unit 10 serving as transfer means has a plurality of conveying roller pairs and conveys the card C to the arrow L side. The horizontal conveyance part 12 which has the discharge roller pair discharged | emitted to the exterior of 2 is arrange | positioned in order.

  The transfer unit 10 includes a platen roller 50 that supports the card C during transfer of an intermediate transfer sheet F or a hologram sheet H to be described later to the card C, and a heat roller 45 that is disposed so as to be movable back and forth with respect to the platen roller 50. ing. The heat roller 45 incorporates a heat generation lamp 46 for heating the intermediate transfer sheet F or the hologram sheet H. An intermediate transfer sheet F or a hologram sheet H is interposed between the platen roller 50 and the heat roller 45.

  The forward / backward movement of the heat roller 45 with respect to the platen roller 50 is performed with a holder 49 that detachably holds the heat roller 45, a driven roller 43 fixed to the holder 49, and a cam shaft 52 centered around the driven roller 43. A lifting / lowering drive unit having a non-circular heat roller raising / lowering cam 51 rotating in the direction (arrow A direction in FIG. 1) and a spring (not shown) that is built in the holder 49 and presses the upper surface of the holder 49 against the heat roller raising / lowering cam 51. Executed.

The intermediate transfer sheet F is supplied from an intermediate transfer sheet supply unit 16 obtained by winding the intermediate transfer sheet F in a roll shape, and is fixed to a frame constituting the transfer unit 10 disposed on both sides of various rollers and the heat roller 45. guided by the guide plate 47 or the like, when the sandwiched between the platen roller 50 and the heat roller 45 on the second card transport path P ₂ through the card C transferred, the intermediate transfer for winding the intermediate transfer sheet F in a roll The sheet is wound around the sheet winding unit 17. Further, the transfer unit 10, the second card transport path P ₂ interposed therebetween arrow L direction permits the conveyance of the conveying roller pair 48 in FIG. 1 the card C mutually pressed on the second card transport path P ₂ is a horizontal It is disposed downstream of the conveying roller pair 11 and upstream of the platen roller 50.

Although not shown, the housing 2 shown in FIG. 1, the region defined by the first card transport path P ₁ and the second card transport path P _2, drives the pulse motors M1, M2 can be normal and reverse rotation A drive mechanism serving as a power source is provided.

  As shown in FIG. 6, the printing apparatus 1 of the present embodiment can manually mount a hologram sheet H instead of the intermediate transfer sheet F. In this case, the roll-shaped intermediate transfer sheet supply unit 16 and the intermediate transfer sheet take-up unit 17 are removed, and the roll-shaped hologram sheet supply unit 29 and the hologram sheet take-up unit are respectively attached to the supply spool shaft 120 and the take-up spool shaft 110. The taker 30 is loaded and the hologram sheet H is passed over. The hologram sheet H has a layer configuration similar to that of the intermediate transfer sheet F shown in FIG. 7B, but differs in that it has a hologram layer in which a hologram is formed in advance instead of the receiving layer. ing.

As shown in FIG. 1, the extension of the second card arrow L direction of the transport path P ₂ of the housing 2, the outlet process such as printing to eject the card C has been completed to the outside of the housing 2 27 Is formed. A stacker 13 for stacking and stocking cards C is detachably attached to the housing 2 below the discharge port 27. An integral transmission sensor (not shown) is disposed between the horizontal conveyance unit 12 and the discharge port 27. Further, the defective card C in which the data writing defect in the information recording unit 8 is found out, the defective card C in which the defect has occurred in the image forming unit 9 or the transfer unit 10, and the second reversing unit 5 as indicated by the arrow D in FIG. An ejection port 28 that is rotated in the tilt direction, which is an intermediate position of R, and ejects downward in the tilt direction is formed. A defective card holder or the like that temporarily holds the defective card C may be attached to the eject port 28.

  The printing apparatus 1 also includes a power supply unit 18 that converts a commercial AC power source into a DC power source that can drive / activate each mechanism unit, control unit, and the like in the housing 2 and a control unit that controls the operation of the entire printing apparatus 1. 19. Furthermore, the printing apparatus 1 has a touch panel (not shown) that displays the state of the printing apparatus 1 and the like on the upper part of the housing 2 according to information from the control unit 19 and can instruct operation commands to the control unit 19 by an operation by an operator. is doing.

  The control unit 19 includes a CPU block 101 that performs control processing of the printing apparatus 1. FIG. 2 shows an outline of the control unit 19 of the printing apparatus 1. The CPU block 101 includes a CPU 102 that operates as a central processing unit with a high-speed clock, a ROM 103 that stores control operations of the printing apparatus 1, a RAM 104 that functions as a work area for the CPU 102, and an internal bus 105 that connects these components. . Further, an external bus 106 is connected to the CPU block 101, and a touch panel display operation control unit 107 that controls display and operation commands on the touch panel, a sensor control unit 108 that controls signals from various sensors, and a drive pulse is sent to each motor. An actuator control unit 109 for controlling a motor driver, an electromagnetic clutch, etc., a thermal head control unit 110 for controlling the thermal energy of the thermal head 20 and a voltage application time per unit pixel, and an external for communicating between the external computer and the printing apparatus 1 An input / output interface 111 and a RAM 112 for storing image information to be printed on the card C are connected. The touch panel display operation control unit 107, the sensor control unit 108, the actuator control unit 109, and the thermal head control unit 110 are connected to the touch panel, sensor, motor driver, electromagnetic clutch, and thermal head 20, respectively.

(Operation of this printer)
The printing apparatus 1 configured as described above operates as follows. Here, an operation when performing indirect transfer on the surface of the card C will be described.

First, the blank card C of the card supply unit 3 is conveyed in the direction of arrow L in FIG. As a result, the blank card C is sent out onto the third card transport path P ₃ , both surfaces are cleaned by the cleaning roller 34 of the cleaner 4, and reaches the information recording unit 8 from the second reversing unit 5. The information recording unit 8 performs processing such as writing of magnetic data and / or IC data on the blank card C using the recording information sent from the control unit 19. If the writing is defective after the process is completed, the card C is ejected to the ejection port 28 described above. In the case of good writing, the card C is conveyed from the second reversing unit 5 to the first reversing unit 6 in the direction of arrow U in FIG.

  Next, the CPU 102 heats the ink of the thermal transfer sheet R with the thermal head 20 to form an image on the receiving layer Fe of the intermediate transfer sheet F. During image formation, the platen roller 21 is rotated counterclockwise, the intermediate transfer sheet F is wound around the intermediate transfer sheet supply unit 16, and the thermal transfer sheet R is wound around the thermal transfer sheet winding unit 15 in synchronization. Is called. The CPU 102 sequentially repeats this process to form an image with the YMC dye on the intermediate transfer sheet F, and then retracts the thermal head 20 with respect to the platen roller 21.

Next, the CPU 102 conveys the intermediate transfer sheet F to the position of the heat roller 45 that is previously separated from the platen roller 50. Also during this time, the card C from the first reversing portion 6 is positioned on the second card transport path P _2, to convey the direction of arrow L in FIG.

  Next, when the leading end of the card C reaches a position where it abuts against the heat roller 45, the heat roller raising / lowering cam 51 is rotated in the direction of arrow A, and the heat roller 45 is separated from the platen roller 50. , The rotation operation of the heat roller lifting cam 51 is stopped. At this time, the back side of the front end of the card C is supported by the platen roller 50 and the front side is pressed against the heat roller 45 via the intermediate transfer sheet F. The card C is supported by a platen roller 50 whose back side rotates counterclockwise, and its front side is pressed against the heat roller 45 via the intermediate transfer sheet F, and is conveyed in the direction of arrow L in FIG. The peeling layer Fc of the intermediate transfer sheet F is peeled from the base film Fa by the heat of the heat generating lamp 46, and the receiving layer Fe on which an image is formed on the surface of the card C and the overcoat layer Fd are integrally transferred. In synchronization with this transfer, the intermediate transfer sheet F is wound around the intermediate transfer sheet winding unit 17.

  When the transfer of the intermediate transfer sheet F to the front side of the card C is completed according to the size size of the card C, the heat roller raising / lowering cam 51 rotates again and the heat roller 45 rises with respect to the platen roller 50. The card C passes through the horizontal conveyance unit 12 and is discharged to the stacker 13 through the discharge port 27.

(Print mode of this machine)
Next, each printing mode in the thermal transfer printing apparatus of the present invention will be described. FIG. 3 is a schematic diagram for explaining a printing mode in the thermal transfer printing apparatus. Here, as an example, “high-definition mode” [first printing mode; FIG. 3A], “intermediate mode” [second printing mode; FIG. 3B], “high-speed mode” [second A case where three modes of the printing mode; FIG. 3 (C)] are provided will be described. In FIG. 3, an arrow M indicates the main scanning direction, and an arrow S indicates the sub-scanning direction.

  Printing by the thermal transfer method is performed by subdividing the entire image into a mesh. One dot, which is the minimum unit of the printing area, is printed on one pixel, which is a finely divided mesh. Usually, the pixels are divided into squares, and the smaller the pixels, the higher the resolution and the higher the resolution of the image.

  FIG. 3A shows an image area (print area) 200 and a pixel 201a in the “high definition mode”. As an example, 600 dpi is assumed here. In such a high resolution mode, it is suitable for printing a character or symbol image, and details of complex images can be expressed precisely, but the printing speed is slow.

  FIG. 3C shows an image area (print area) 200 and a pixel 201c in the “high-speed mode”. As shown in the figure, the pixel 201c is a square having a size obtained by doubling the pixel 201a of FIG. 3A in both the main scanning direction and the sub-scanning direction (that is, 300 dpi). In other words, two adjacent heating elements in the main scanning direction of the thermal head 20 print the same print data to form a pseudo 300 dpi. As described above, when printing a gradation image such as a photograph, what is important is gradation, and high resolution is not particularly required in many cases. Instead of requiring high resolution, the printing speed can be increased. Therefore, the “high-speed mode” as described above is mainly used for printing gradation images. In the “high speed mode”, it is possible to set the conveyance speed of the print medium (here, the card C) to a speed higher than that in the “high definition mode”.

  FIG. 3B shows an image area (print area) 200 and a pixel 201b in the “intermediate mode”. As shown in the figure, the pixel 201b is a rectangle having a size obtained by doubling the pixel 201a in FIG. 3A in the sub-scanning direction. That is, here, it becomes 600 dpi in the main scanning direction and 300 dpi in the sub-scanning direction. In this mode, the pixel 201b has a rectangular shape extending only in the sub-scanning direction, thereby realizing high resolution in the main scanning direction and suppressing the resolution in the sub-scanning direction in order to shorten the printing time. By doing so, it is possible to achieve both moderate print quality and high-speed printing. This intermediate mode is preferably used for an image that requires a particularly precise expression among gradation images. In the “intermediate mode”, it is possible to set the conveyance speed of the printing medium (here, the card C) to a higher speed than in the “high definition mode”.

(Operation control of the present invention)
Next, control for realizing the print mode as described above will be described.

  FIG. 4 is a schematic diagram showing the state of dots actually printed in the “high-definition mode” and the “intermediate mode” shown in FIG. 3 and the heat generation change of the thermal head. FIG. 4A shows the case of “high definition mode”, and FIG. 4B shows the case of “intermediate mode”.

  In FIG. 4A, the dot 202a is printed on the square pixel 201a, and in FIG. 4B, the dot 202b is printed on the rectangular pixel 201b. As can be seen from this figure, two dots in the “high definition mode” are expressed by one dot in the “intermediate mode”.

  For this purpose, as shown in FIG. 5, in the mode for printing at a higher speed than in the “high-definition mode”, it is necessary to make the voltage application time to the thermal head 20 (heating element) in one pixel area longer than in the “high-definition mode”. There is. FIG. 5A is a diagram showing the area of one pixel and the voltage application time to the heating element in the “high-definition mode”, and FIG. 5B is the voltage application time to one pixel area and the heating element in the “intermediate mode”. It is a figure which shows time. Here, the voltage application time to the heating element in one pixel area in the “high definition mode” (FIG. 5A) is t1, and the voltage application time to the heating element in one pixel area in the “intermediate mode” [FIG. B)] is t2, it is necessary to satisfy t2> t1. In the “intermediate mode”, the conveyance speed of the printing medium (here, card C) is higher than that in the “high definition mode”, so that the voltage application time to the heating element is substantially “intermediate mode” than in the “high definition mode”. However, when the voltage application time per unit pixel is considered as shown in FIG. 5, t2 is set longer than t1 in order to make the printing density in one pixel the same.

  Here, as shown in FIG. 4A, when printing is performed for each dot, it is necessary to cool the thermal head 20 once after the printing for one dot is completed until the next dot is printed. . On the other hand, in FIG. 4B, since the dot 201b is one dot, it is not necessary to cool the thermal head 20. Therefore, since the time to heat the thermal head 20 once and then generate heat again can be omitted, the print medium can be conveyed faster in the “intermediate mode” than in the “high-definition mode”.

  At this time, the voltage application time per unit pixel is calculated by the thermal head control unit 110 according to the conveyance speed of the printing medium and the area of one pixel.

  By the way, as described above, “high-definition mode” (first print mode) is used when printing characters or symbols, and “intermediate mode” or “high-speed mode” (when printing images such as photographs). It is preferable to set the second printing mode). Usually, characters or symbols are mostly black and white binary images, and images such as photographs are often color gradation images. Therefore, when using the single color band [for example, Bk (black)] of the thermal transfer sheet (ink ribbon) R and using the color bands other than black [Y (yellow), M (magenta), C (cyan)]. Thus, the mode of the thermal transfer printing apparatus may be automatically set / changed. That is, it may be possible to set in advance such that the “high accuracy mode” is used when the single color band of the thermal transfer sheet (ink ribbon) R is used, and the “intermediate mode” or the “high speed mode” is used when the color band is used.

  As described above, in the thermal transfer printing apparatus according to the present invention, the first printing mode in which the size of one heating element constituting the thermal head is printed in units of pixels and one heating element is extended in the sub-scanning direction. Corresponding to a plurality of different printing modes of the second printing mode for printing in the pixel size as a unit of pixel, corresponding to the transport speed of the print medium in the sub-scanning direction, and applying voltage to each heating element of the thermal head Since each is controlled individually, high-resolution printing and high-speed printing are possible.

  In the embodiment of the present thermal transfer printing apparatus, characters or images are primarily transferred to a film-like intermediate transfer medium by a thermal head, and the primary-transferred film-like intermediate transfer medium is pressed against the print medium, The thermal transfer printing apparatus that prints the character or image on the print medium has been described. The present invention is applied to an apparatus that directly transfers information such as an image / character on a recording medium such as paper or plastic. It goes without saying that it is possible.

  The present invention relates to a thermal transfer printing apparatus that directly or indirectly thermally transfers and prints information such as images and characters on a recording medium such as paper or plastic, and in particular, for resolution printing and image printing for printing characters or symbols. The present invention relates to a thermal transfer printing apparatus capable of gradation printing, and has industrial applicability.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 2 Case 3 Card supply part 4 Cleaner 5 2nd inversion part 6 1st inversion part 8 Information recording part 9 Image formation part 10 Transfer part 11 Horizontal conveyance roller pair 12 Horizontal conveyance part 13 Stacker 14 Thermal transfer sheet supply part 15 Thermal transfer sheet take-up unit 16 Intermediate transfer sheet supply unit 17 Intermediate transfer sheet take-up unit 18 Power supply unit 19 Control unit 20 Thermal head 21 Platen roller 27 Discharge port 28 Eject port 29 Hologram sheet supply unit 30 Hologram sheet take-up unit 34 Cleaning roller 43 driven roller 45 heat roller 46 heat generation lamp 47 guide plate 48 conveying roller pair 49 holder 50 platen roller 51 heat roller raising / lowering cam 52 cam shaft 101 CPU block 102 CPU
103 ROM
104 RAM
105 Internal bus 106 External bus 107 Touch panel display operation control unit 108 Sensor control unit 109 Actuator control unit 110 Thermal head control unit 111 External input / output interface 112 RAM
200 Image area (print area)
201a pixel 201b pixel 201c pixel 202a dot 202b dot

Claims (6)

A thermal head composed of a plurality of heating elements arranged in the main scanning direction;
An ink ribbon that holds ink that is thermally dissolved by overheating of the heating element;
Conveying means for conveying the print medium in the sub-scanning direction;
Control means for controlling the thermal head and the transport means,
The control means has a first printing mode for printing the size of one heating element constituting the thermal head as a pixel unit, and a size obtained by extending one heating element in the sub-scanning direction. Corresponding to a plurality of different printing modes with the second printing mode for printing as a pixel unit, along with the conveying speed of the print medium in the sub-scanning direction by the conveying means, the unit per pixel for each heating element of the thermal head A thermal transfer printing apparatus, wherein the voltage application time is individually controlled. The control means includes
In the first print mode, the transport speed of the print medium by the transport means is controlled to the first transport speed,
In the second printing mode, the transport speed of the print medium by the transport means is controlled to a second transport speed that is faster than the first transport speed.
The thermal transfer printing apparatus according to claim 1.   In the second printing mode, when the control unit controls the transport speed of the print medium to the second transport speed, the control unit associates the driving time of the thermal head with the transport speed of the print medium, and The thermal transfer printing apparatus according to claim 2, wherein the voltage application time is extended. When printing characters on the print medium, printing in the first print mode is performed,
When printing an image on the print medium, printing in the second print mode is performed.
The thermal transfer printing apparatus according to claim 3. In the ink ribbon, a plurality of different bands of at least one color band and one single-color band are formed in the surface order,
In the monochrome printing using only the single color band and the color printing using the color band, the control means transports the print medium by the transport means in the first print mode and the second print mode. The thermal transfer printing apparatus according to claim 4, wherein the voltage application time to the thermal head is changed.   The thermal head primarily transfers characters or images to a film-like intermediate transfer medium, and presses the primary-transferred film-like intermediate transfer medium against the print medium, thereby printing the characters or images on the print medium. The thermal transfer printing apparatus according to any one of claims 1 to 5, wherein:

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