JP2011167849A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer in which such a phenomenon can be prevented/suppressed that a printing position on printing paper is shifted owing to the errors of assembled positions of thermal heads. <P>SOLUTION: The printer includes detection parts 34M, 34C, 34L for detecting marks m1, m2, m3 and the printing paper edge Se, which are printed by a plurality of thermal heads, respectively; and a control part for specifying the positional shift amount of each thermal head in the width direction with respect to the printing paper on the basis of the marks m1, m2, m3 and printing paper edge Se which are detected by the detection parts 34M, 34C, 34L and correcting the printing position when printing is performed next time by each thermal head on the basis of the specified positional shift of each thermal head in the width direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printer that performs thermal transfer printing processing with a thermal head.

  2. Description of the Related Art Conventionally, printers that perform thermal transfer print processing on paper with a thermal head having a plurality of heating elements arranged in the width direction of the paper are known. This type of printer is configured to thermally transfer ink of an ink ribbon heated by a heating element to a sheet sandwiched between a thermal head and a platen in a state where ink ribbons are overlapped.

  Here, if there is an error in the assembly position of the thermal head, specifically, if the assembly position of the thermal head is shifted in the paper width direction, the print image formed on the paper is the thermal head. This shifts toward the end in the sheet width direction (the end of the sheet) by an error in the assembling position, which can lead to a decrease in print quality. In particular, in a so-called multi-head type printer in which a plurality of thermal heads are arranged in the paper transport direction, if the thermal head assembly position deviates from the normal assembly position in the paper width direction, There is a problem in that the print positions do not match and so-called misregistration (color misregistration) occurs, and a beautiful image print cannot be output.

  Accordingly, the applicant of the present invention provides an imaging unit that captures the paper and acquires the imaging data corresponding to each thermal head, and obtains the image data based on the displacement in the width direction of the paper with respect to the thermal head calculated from the imaging data. A printer configured to be corrected has been devised (see Patent Document 1).

JP 2007-331345 A

  The present applicant uses an approach different from the technique disclosed in Patent Document 1 described above to perform appropriate print processing even when the thermal head assembly position is shifted from the predetermined assembly position in the paper width direction. We came up with a printer that could do that.

  That is, the present invention relates to a printer provided with at least one or more thermal heads having a plurality of heating elements arranged in the width direction of a sheet on which printing processing is performed, and a control unit that controls thermal transfer printing processing by the thermal head. Is. The printer according to the present invention further includes a head position detection mark subjected to thermal transfer printing processing by at least one thermal head, and at least one detection unit that detects a reference position of the paper. The relative position of the one or more thermal heads with respect to the paper is specified based on the head position detection mark and the paper reference position detected in Step 1, and the print position by the thermal head based on the relative position of the specified one or more thermal heads or It is characterized by being configured to correct the position of the thermal head itself.

  Here, the printer of the present invention may be a so-called multi-head type printer having a plurality of thermal heads or a so-called single head type printer having a single thermal head. The “head position detection mark” is a mark formed on the paper by the print processing of the thermal head itself in order to grasp the position of the thermal head itself (actual assembly position of the thermal head) assembled in the printer. The “head position detection mark” may be, for example, a straight line extending in the paper conveyance direction, a line such as a dotted line or a chain line, a shape such as a circle or a polygon, or a character or a symbol. The “paper reference position” may be any position on the paper, and the side edge of the paper itself is adopted as the “paper reference position”, or the line or shape printed on the paper, or Holes (regardless of size and shape) formed on the paper can be adopted as the “paper reference position”.

  In such a printer, a thermal position in which the detection unit detects the head position detection mark and the paper reference position, and the control unit prints the head position detection mark from the head position detection mark and the paper reference position. Since the displacement amount (deviation amount) of the head in the paper width direction is calculated, the relative position between the thermal head actually assembled in the printer and the paper facing the thermal head in the printer is calculated. Accurately grasp. The printer of the present invention prints the head position detection mark based on the thermal head displacement calculated by the control unit even when the thermal head assembly position is shifted in the paper width direction. It is configured to correct the print position at the next and subsequent print processing by the thermal head, or to correct the position of the thermal head itself that has been printed with the head position detection mark. Can be formed.

  In particular, when the printer of the present invention is applied to a multi-head type printer, the print processing by each thermal head is prevented from shifting in the paper width direction, and a beautiful print image free from misregistration (color shift). Can be output. Further, when the printer of the present invention is applied to a single head type printer, the print processing area by the single thermal head is prevented from shifting in the paper width direction, and the print processing is suitably performed at the regular print position. be able to.

  In order to efficiently assemble the thermal head and the detection unit inside the printer, the thermal head and the detection unit may be unitized, and a plurality of such unitized print units may be arranged in the paper transport direction. When configuring a multi-head type printer arranged side by side, the head position detection mark that has been subjected to thermal transfer printing with the thermal head of the print unit that is relatively upstream is detected by the print unit that is relatively downstream. Can be set to be detected by the unit. In such a printer, by utilizing the fact that the relative positional relationship between the thermal head and the detection unit in each print unit is uniform, a relatively downstream print unit (hereinafter abbreviated as “downstream print unit”). ) By detecting a head position detection mark and a paper reference position printed by a thermal head of a relatively upstream print unit (hereinafter sometimes referred to as “upstream print unit”). The relative positional relationship between the thermal head of the upstream print unit and the paper and the thermal head of the downstream print unit (the amount of displacement of the thermal print head of the upstream print unit in the paper width direction) can be grasped at a time, which is preferable.

  Furthermore, in a printer that performs thermal transfer print processing with a thermal head on one side (for example, the front side) of a sheet, a thermal head or an ink ribbon must be disposed at a position facing the front side of the sheet. In such a printer, since there is a space limitation if the detection unit is further arranged at a position facing the front side of the sheet, the detection unit is positioned at a position facing the back side of the sheet (the other side of the sheet). It is preferable to arrange. In this case, the detection of the head position detection mark formed on the front side of the paper is performed by watermarking the paper from the back side of the paper.

  In the printer of the present invention, the back side printing is performed on the back side of the paper (not limited to thermal transfer printing) on the upstream side of the thermal head (on the upstream side of the thermal head on the most upstream side of the multi-head type printer). A head may be further provided, and a mark printed by the back surface print head may be employed as the paper reference position. With such a printer, the paper reference position can be formed on the paper by using a back surface print head capable of performing printing processing on the back surface of the paper and printing information, a destination, and the like.

  According to the present invention, it is possible to accurately grasp the relative position between the thermal head assembled in the printer and the paper, and even if the thermal head assembly position is shifted in the paper width direction, the control unit By correcting the print position by the thermal head that has printed the head position detection mark based on the displacement amount of the thermal head calculated by the above, or by correcting the position of the thermal head itself that has printed the head position detection mark Thus, it is possible to output a paper on which a clean print image in which the print position is not shifted is formed on the paper.

1 is a schematic diagram of an internal configuration of a printer according to an embodiment of the present invention. The partially expanded view of FIG. FIG. 2 is a simplified internal configuration diagram of the printer according to the embodiment. 6 is a flowchart at the time of test print processing of the printer according to the embodiment. The schematic diagram which looked at the paper which passes above the detection part of M unit from the front side. The schematic diagram which looked at the paper which passes above the detection part of C unit from the front side. The schematic diagram which looked at the paper which passes above the detection part of L unit from the front side. FIG. 3 is a view corresponding to FIG. 3 of a printer according to a modification (first modification) of the embodiment. FIG. 7 is a view corresponding to FIG. 7 of the printer according to the first modification. FIG. 1 is a diagram corresponding to FIG. 1 of a printer according to another modified example (second modified example) of the embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The printer 1 according to the present embodiment is a multi-head printer in which a plurality of print units 3 are arranged along the conveyance direction A of the paper S as shown in FIGS. The printer 1 of the present embodiment has a plurality of print units 3 arranged in an arc as shown in FIG. 1, but in FIG. 3, the plurality of print units 3 are shown in a straight line for convenience of explanation. The arrangement mode of the print unit 3 can be changed as appropriate according to the transport path of the paper S.

  As shown in FIG. 1, the printer 1 includes a paper feeding unit 2 that can store a long paper S wound in a roll shape, and a plurality of thermal transfer printing processes performed on the paper S delivered from the paper feeding unit 2. The printing unit 3 includes a cut unit 5 provided on the paper discharge port 4 side, and a control unit (not shown) that controls the operation of each unit. In the following description, “upstream side” and “downstream side” mean the upstream side and the downstream side in the conveyance direction A of the paper S, respectively.

  Each print unit 3 includes a thermal head 31 that performs thermal transfer printing processing on the paper S, a paper transport mechanism 32, and an ink ribbon 33, as shown in FIG. 2 which is a partially enlarged view of FIGS. Is.

  The thermal head 31 arranges a large number of heating elements (not shown) in the width direction of the paper S in an area larger than the width dimension of the paper S in one or a plurality of rows, and heats the heating elements based on image data or the like. In this case, the heat transfer printing process is performed on the paper S.

  The sheet transport mechanism 32 includes a platen roller 321 that presses and sandwiches the sheet S with the thermal head 31, a set of a feed roller 322 and a pinch roller 323 arranged on the upstream side of the platen roller 321, and a platen roller 321. Also, it is configured using a set of a feed roller 322 and a pinch roller 323 arranged on the downstream side. Each pinch roller 323 can pinch the sheet S between the nipping position where the sheet S can be nipped with each opposing feed roller 322 and the feed roller 322 spaced apart from each nesting feed roller 322. It is provided so as to be movable between a non-clamping position (not shown). Each feed roller 322 rotates synchronously, and the platen roller 321 rotates in synchronization with or following the feed roller 322.

  As shown in FIG. 2, the ink ribbon 33 detachably mounted on each print unit 3 is unwound from the supply side ribbon core 331, guided to the thermal head 31 side by the supply side guide roller 332, and adhered to the paper S. In this state, after passing through the thermal head 31, the sheet is peeled off from the paper S by the peeling guide roller 333, and is taken up on the winding side ribbon core 334. In this embodiment, the supply-side ribbon core 331 and the supply-side guide roller 332 are arranged on the upstream side of the thermal head 31, and the peeling guide roller 333 and the take-up-side ribbon core 334 are arranged on the upstream side of the thermal head 31. .

  In the thermal transfer printer 1 according to the present embodiment, a plurality of such print units 3 are arranged at predetermined pitches along the transport direction A of the paper S. Each print unit 3 is set with an ink ribbon 33 in which different color inks are applied to the ribbon, and the thermal transfer printing process is sequentially performed on the front side of the paper S conveyed in a predetermined direction. In the following description, “Y unit 3Y”, “M unit 3M” are arranged in order from the upstream side corresponding to the ink colors (Yellow, Magenta, Cyan) of the ink ribbon 33 mounted on each print unit 3. ”Or“ C unit 3C ”, or the thermal head 31 of each print unit 3 may be referred to as“ Y head 31Y ”,“ M head 31M ”, or“ C head 31C ”. The print unit 3 arranged on the most downstream side is for overprinting in which a protective layer is formed on the print surface (front surface) of the paper S printed by the Y head 31Y, M head 31M, and C head 31C. In the following description, it may be referred to as “L unit 3L”, or the thermal head 31 of this print unit 3 (L unit 3L) may be referred to as “L head 31”.

  Further, the control unit is configured by a CPU (not shown) or the like that is communicably connected to each unit (for example, the thermal head 31 or the like) constituting each print unit 3, and the width of each thermal head 31 is controlled by this control unit. A heating element region (energization element) to be energized among the heating elements arranged in the direction is set, the sheet S is transported by the sheet transport mechanism 32, the head-up operation and the head-down operation of each thermal head 31, and the sheet feeding unit. The overall operation of the printer 1 is controlled, such as the sheet S supply operation by No. 2 and the cutting operation by the cutting unit 5.

  In such a thermal transfer printer 1, each feed roller 322 constituting the paper transport mechanism 32 of the print unit 3 on the most upstream side of each print unit 3 is rotated in the transport direction A and wound in a roll shape in the paper feed unit 2. The sheet S being conveyed is conveyed while passing between each feed roller 322 and each pinch roller 323 at the nipping position. In the printer 1 according to the present embodiment, when the paper S is transported without performing the sublimation printing process by the thermal head 31, the thermal head 31 cannot be sandwiched between the platen roller 321 and the position ( Although the paper S is smoothly transported by waiting at the head up position, the position where the paper S can be sandwiched between the thermal head 31 and the platen roller 321 in FIGS. 1 to 3 (head down position). The state moved to is shown.

  In the printer 1 of the present embodiment, the heating elements of the thermal heads 31 are appropriately arranged on the print surface (front surface) of the paper S sequentially sent out from the paper supply unit 2 in accordance with a print processing command from the control unit. The ink is energized and the ink of each ink ribbon 33 is printed on the paper S by thermal transfer. The print processing command is, for example, a command for instructing whether or not to transfer the ink on the ink ribbon 33 to the paper S based on print image input information that is information about a print image input before the start of the print processing. (Print pattern). The front side of the paper S is colored by sequentially performing thermal transfer printing processing by the thermal head 31 (Y head 31Y, M head 31M, C head 31C) of each print unit 3 (Y unit 3Y, M head 31M, C head 31C). A print image can be formed, and the paper S on which the color print image is formed can be discharged from the paper discharge port 4 after being cut into a predetermined size by the cutting unit 5.

  By the way, there is an error in the assembly position of the thermal head 31 (Y head 31Y, M head 31M, C head 31C, L head 31L) in each print unit 3 (Y unit 3Y, M unit 3M, C unit 3C, L unit 3L). Yes, when the relative position of each thermal head 31 (Y head 31Y, M head 31M, C head 31C, L head 31L) with respect to the sheet S is shifted in the width direction of the sheet S from the normal relative position, The thermal transfer print position by the thermal head 31 (Y head 31Y, M head 31M, C head 31C, L head 31L) is shifted in the paper width direction, so-called misregistration (color shift) is caused, resulting in a decrease in print quality. To do.

  Therefore, the printer 1 according to the present embodiment specifies the assembly position of each thermal head 31 with respect to the paper S by using a print process at the time of test printing performed at an appropriate timing such as before shipment or before use. The print position from the next time on by the head 31 can be corrected.

  Specifically, as shown in FIGS. 1 to 3, each print unit 3 (Y unit 3Y, M unit 3M, C unit 3C, L unit 3L) is provided with a thermal head 31 (Y head 31Y, M head 31M, C). A head position detection mark (for example, a straight line extending in the transport direction A of the sheet S and parallel to the side edge Se of the sheet S) printed by the head 31C and the L head 31L is abbreviated as “mark” in the following description. ) Is detected (detection unit 34Y, detection unit 34M, detection unit 34C, detection unit 34L). Each detector 34 (detector 34Y, detector 34M, detector 34C, detector 34L) is communicably connected to the controller. In the present embodiment, each detection unit 34 (detection unit 34Y, detection unit 34M, detection unit 34C, detection unit 34L) is configured using, for example, a known CIS (contact image sensor). Note that various detection devices (CCD, CMOS, etc.) other than the CIS may be employed as the detection unit 34.

  Further, the thermal head 31 (Y head 31Y, M head 31M, C head 31C, L head 31L) and detection unit 34 (detection unit) in each print unit 3 (Y unit 3Y, M unit 3M, C unit 3C, L unit 3L). 34Y, the detection unit 34M, the detection unit 34C, and the detection unit 34L) are constant, and the detection unit 34 is disposed upstream of the thermal head 31. Further, in the present embodiment, each detection unit 34 (detection unit 34Y, detection unit 34M, detection unit 34C, detection unit 34L) is arranged on the back side of the paper S, and the paper S is marked through the back side of the paper S. Is configured to read. Although not shown, an illuminator such as an LED is disposed at a position facing the detection unit 34 with the paper S interposed therebetween, and the detection unit 34 uses the irradiation light from the illuminator as auxiliary light. Increases detection accuracy. Of course, it is also possible to detect the mark only by the reflected light of the light irradiated on the paper S from the detection unit 34 itself without providing an illuminator. In the present embodiment, the thermal head 31 of the print unit 3 (for example, the Y unit 3Y) disposed relatively upstream in the print unit 3 (for example, the Y unit 3Y and the M unit 3M) adjacent in the transport direction A of the paper S. A mark (Y mark m1 to be described later) that has been subjected to thermal transfer printing processing by the (Y head 31Y) is detected by the detection unit 34 (detection unit 34M) of the print unit 3 (for example, M unit 3M) that is disposed relatively downstream. (See FIG. 5).

  Further, in the thermal transfer printer 1 of the present embodiment, the detection unit 34 causes the reference position in the width direction of the sheet S, specifically, the side edge Se of the sheet S, that is, the end on the width direction end side, to be detected. The detection unit 34 having a width dimension larger than the width dimension of the sheet S is used so that the section (hereinafter referred to as “sheet end Se”) can also be detected.

  In the thermal transfer printer 1 of the present embodiment, the control unit controls the relative position of the thermal head 31 with respect to the paper S based on the mark detected by the detection unit 34 and the paper edge Se, in other words, the thermal head 31 in the paper width direction. The displacement amount (deviation amount) is specified, and the print position by the thermal head 31 is corrected based on the specified relative position (displacement amount: deviation amount) of the thermal head 31.

  In the control unit, the detection unit 34 detects the mark printed by the thermal head 31 of the print unit 3 disposed on the relatively upstream side. The relative position between the print-processed thermal head 31 and the print unit 3 to which the detection unit 34 belongs is specified, and the paper end Se is detected by the detection unit 34, whereby the detection unit 34 and the paper S, that is, the print unit to which the detection unit 34 belongs. 3 and the relative position of the paper S are specified. Accordingly, the mutual positional relationship between the thermal head 31 of the print unit 3 disposed relatively upstream, the thermal head 31 of the print unit 3 disposed relatively downstream, and the paper S can be specified. Specifically, among the plurality of heating elements arranged in the width direction in each thermal head 31, heat is applied to one or more preset heating elements, and a straight line (mark) on the front side of the sheet S parallel to the sheet edge Se is marked. ) Is set to be formed by a thermal transfer printing process. Then, the detection unit 34 detects the mark and the sheet edge Se to identify the distance from the sheet edge Se to the mark, and the relative relationship between the thermal head 31 and the sheet S on which the mark is printed based on the identified distance. A position (a displacement amount in the width direction of the thermal head 31 and a displacement amount in the width direction of the thermal head 31) is calculated. The control unit calculates the relative position between each thermal head 31 and the sheet S by such a processing procedure, and based on the calculated relative position so that the thermal transfer print position from the next time on each thermal head 31 does not shift. The thermal transfer print position by the thermal head 31 is corrected. In this embodiment, based on the displacement amount in the width direction of each thermal head 31 calculated by the control unit, the heating element region (energization element) to be energized among the heating elements arranged in the width direction in each thermal head 31 is changed. Thus, the thermal transfer print position by each thermal head 31 is corrected.

  Next, the operation and action of the thermal transfer printer 1 during test printing will be described with reference to FIGS. 5 to 7 are diagrams schematically illustrating a state where the sheet S passing above the detection units 34M, 34C, and 34L is viewed from the front side.

  First, the sheet S is transported along the transport direction A by the rotation operation of each feed roller 322 and each pinch roller 323 as in the normal print processing. When the sheet S passes through the Y unit 3Y which is the most upstream side print unit 3, the Y head 31Y of the Y unit 3Y attaches the Y head position detection mark (hereinafter referred to as "Y mark m1") to the sheet S. ) Is printed (Y mark printing step S1: see FIG. 4). Next, in the printer 1 of the present embodiment, the M unit 3M, which is the print unit 3 to which the paper S arrives following the printing process of the Y mark m1, as shown in FIG. 5, is detected by the detection unit 34M of the M unit 3M. The edge Se is detected (paper edge detection step S2: see FIG. 4) and the Y mark m1 printed by the Y head 31Y is detected (Y mark detection step S3: see FIG. 4). Thereby, the relative position between the sheet S and the detection unit 34M of the M unit 3M and the relative position between the Y head 31Y and the detection unit 34M of the M unit 3M can be grasped. The printer 1 of the present embodiment detects the sheet end Se corresponding to the sheet reference position in the present invention and the Y mark m1 printed by the Y head 31Y by the detection unit 34M of the M unit 3M, and the detected data is M By transmitting from the unit 3M to the control unit, the control unit specifies (calculates) the distance from the side edge (paper end Se) of the paper S passing through the M unit 3M to the Y mark m1, and the Y head 31Y with respect to the paper S Can be specified (calculated) (Y head displacement amount specifying step S4: see FIG. 4).

  Subsequently, when the sheet S passes through the M head 31M of the M unit 3M, the printer 1 according to the present embodiment uses the M head 31M to mark the position of the M head 31M (hereinafter, “M mark m2”). Is printed) (M mark printing step S5: see FIG. 5). Next, in the C unit 3C, which is the print unit 3 to which the paper S arrives following the printing process of the M mark m2, the printer 1 according to the present embodiment uses the detection unit 34C of the C unit 3C to detect the end of the paper as shown in FIG. Se is detected (sheet end detection step S6: see FIG. 4) and the M mark m2 printed by the M head 31M is detected (M mark detection step S7: see FIG. 4). Thereby, the relative position between the sheet S and the detection unit 34C of the C unit 3C and the relative position between the M head 31M and the detection unit 34C of the C unit 3C can be grasped. The printer 1 according to the present embodiment detects the sheet end Se and the M mark m2 printed by the M head 31M by the detection unit 34C of the C unit 3C, and transmits the detection data from the C unit 3C to the control unit. Thus, the control unit specifies (calculates) the distance from the side edge (sheet end Se) of the sheet S passing through the C unit 3C to the M mark m2, and specifies the displacement amount in the width direction of the M head 31M relative to the sheet S ( (M head displacement amount specifying step S8: see FIG. 4).

  Next, when the sheet S passes through the C head 31C of the C unit 3C, the printer 1 of the present embodiment uses the C head 31C to detect the position detection mark (hereinafter, “C mark m3”) of the C head 31C. (Referred to as C mark printing step S9: see FIG. 4). Next, as shown in FIG. 7, the printer 1 according to the present embodiment uses the detection unit 34L of the L unit 3L to detect the sheet in the L unit 3L that is the print unit 3 to which the sheet S arrives following the printing process of the C mark m3. The edge Se is detected (paper edge detection step S10: see FIG. 4) and the C mark m3 printed by the C head 31C is detected (C mark detection step S11: see FIG. 4). Thereby, the relative position between the sheet S and the detection unit 34L of the L unit 3L and the relative position between the C head 31C and the detection unit 34L of the L unit 3L can be grasped. The printer 1 according to the present embodiment detects the sheet end Se and the C mark m3 printed by the C head 31C by the detection unit 34L of the L unit 3L, and transmits the detection data from the L unit 3L to the control unit. As a result, the control unit specifies (calculates) the distance from the side edge (sheet end Se) of the sheet S passing through the L unit 3L to the C mark m3, and specifies the amount of displacement in the width direction of the C head 31C relative to the sheet S ( (C head displacement amount specifying step S12: see FIG. 4).

  In the present embodiment, each mark (Y mark m1, M mark m2, C mark m3) among a plurality of heating elements arranged in the width direction in each thermal head 31 (Y head 31Y, M head 31M, C head 31C) is marked. A heating element that gives heat when printing is set in advance. Specifically, if the assembly position of each thermal head 31 (Y head 31Y, M head 31M, C head 31C) is a normal position, each thermal head 31 (Y head 31Y, M head 31M, C head 31C). ), Each thermal head 31 is formed so that the marks (Y mark m1, M mark m2, C mark m3) are formed at equal pitches in the paper width direction without overlapping each other as shown in FIG. In the (Y head 31Y, M head 31M, and C head 31C), heating elements that give heat are appropriately set.

  Note that the printing process by the L head 31L of the L unit 3L may be omitted at the time of test printing, and each mark (Y mark m1, M mark m2, C mark m3) is printed on the paper S that has passed through the L unit 3L. When the entire area has passed through the cut portion 5, it is cut by the cut portion 5 and discharged from the paper discharge port 4. Note that the operator and the user visually observe the arrangement of the marks (Y mark m1, M mark m2, and C mark m3) printed on the discharged paper S so that each thermal head 31 (Y head 31Y, M It is possible to visually grasp whether or not the assembly position of the head 31M and the C head 31C) is appropriate.

  In this embodiment, the print unit 3 including the thermal head 31 (L head 31L) that performs overprint processing (processing to form a protective layer) is disposed on the most downstream side. However, the thermal head 31 (L Even if there is a slight error in the assembly position of the head 31L), this error is unlikely to be a direct factor in the occurrence of so-called misregistration (color misregistration). Therefore, the thermal head 31 (L head 31L) is assembled. The position error can be ignored unless it is very large. That is, in the printer 1 having the plurality of thermal heads 31 as in the present embodiment, the thermal head that can be corrected by the control unit (correction target thermal head) is directly affected by misregistration. It is a thermal head that can be a factor. In this embodiment, thermal heads (Y heads 31Y, M) other than the thermal head (L head 31L) that performs overcoat printing processing among all thermal heads (Y head 31Y, M head 31M, C head 31C, L head 31L). The head 31M and the C head 31C) are correction target thermal heads.

  In the printer 1 of this embodiment, the amount of displacement in the width direction of each thermal head 31 (Y head 31Y, M head 31M, C head 31C) with respect to the paper S specified (calculated) by the control unit is set in advance. If it does not match the value or exceeds a preset allowable range (S13Y: see FIG. 4), it is determined that the assembly position of the thermal head 31 is not a regular assembly position, and is specified (calculated). ), The thermal heads 31 (Y head 31Y, M head) in the subsequent thermal transfer printing process based on the displacements in the width direction of the thermal heads 31 (Y head 31Y, M head 31M, C head 31C) with respect to the sheet S. The thermal transfer print position (thermal transfer print area) by 31M, C head 31C) is corrected (correction step S14: see FIG. 4). Specifically, the thermal head 31 (the thermal transfer print area) by the thermal heads 31 (the Y head 31Y, the M head 31M, and the C head 31C) in the subsequent and subsequent thermal transfer printing processes is matched. In the Y head 31Y, the M head 31M, and the C head 31C), a heating element range (energizing element) to be energized when printing is set among a plurality of heating elements arranged in the width direction is set.

  In the printer 1 of the present embodiment, the energization of each thermal head 31 according to the width direction displacement amount (deviation amount) of each thermal head 31 (Y head 31Y, M head 31M, C head 31C) with respect to the paper S is performed by the above procedure. The element can be corrected. As a result, in the present printer 1, the sheet S is the thermal head 31 (Y head 31Y, M head 31M, C) of each print unit 3 (Y unit 3Y, M unit 3M, C unit 3C) in the next and subsequent thermal transfer printing processes. When passing between the head 31C) and the platen roller 321, the heating elements of the thermal heads 31 (Y head 31Y, M head 31M, C head 31C) are energized based on the energizing elements corrected by the control unit. The respective color inks applied to the respective ink ribbons 33 in accordance with a print processing command (print pattern) are subjected to thermal transfer printing on the paper S, whereby the print areas by the thermal heads 31 (Y head 31Y, M head 31M, C head 31C) are printed. Misregistration that shifts from each other does not occur, beautiful color It is possible to form an image printed on the paper S.

  As described above, the printer 1 according to the present embodiment uses the head position detection mark (Y) based on the amount of displacement in the width direction of each thermal head 31 (Y head 31Y, M head 31M, C head 31C) calculated by the control unit. Since the thermal head 31 (the Y head 31Y, the M head 31M, and the C head 31C) that has printed the mark m1, the M mark m2, and the C mark m3) is configured to correct the print position at the next print processing, During the next printing process, it is possible to output a sheet S on which a print image in which the print positions of these thermal heads 31 (Y head 31Y, M head 31M, and C head 31C) match is formed.

  In the printer 1 of this embodiment, the print unit 3 (Y unit 3Y, M unit 3M, C unit 3C, and L unit 3L) in which the thermal head 31 and the detection unit 34 are unitized is used. The thermal head 31 and the detection unit 34 can be efficiently assembled and the thermal head 31 (Y head 31Y, M head 31M, C) in each print unit 3 (Y unit 3Y, M unit 3M, C unit 3C, L unit 3L). The head 31C, the L head 31L) and the detection unit 34 (the detection unit 34Y, the detection unit 34M, the detection unit 34C, the detection unit 34L) take advantage of the uniform relative positional relationship, for example, the Y head 31Y and the M head 31) in relation to the print unit 3 (M 3M) detects the mark (Y mark m1) and the sheet edge Se printed by the thermal head 31 (Y head 31Y) of the print unit 3 (Y unit 3Y) disposed relatively upstream. Thus, the relative positional relationship between the thermal head 31 (Y head 31Y) of the upstream print unit 3 (Y unit 3Y), the paper S, and the thermal head 31 (M head 31M) of the downstream print unit 3 (M unit 3M) is once set. Can grasp. In the present embodiment, in each print unit 3, the detection unit 34 is disposed upstream of the thermal head 31 along the paper conveyance direction during print processing, and each detection unit 34 is disposed relatively upstream. Since the mark printed by the thermal head 31 of the unit 3 is detected, there is no detection process by the detection unit 34Y of the Y unit 3Y which is the most upstream print unit 3, and the detection unit 34Y is omitted. be able to.

  The present invention is not limited to the embodiment described above. For example, the order of the print units arranged in the paper transport direction (the order of the ink colors to be printed) may be changed as appropriate, and an overcoat for forming a protective layer on the print surface (front surface) of the paper. Instead of or in addition to the printing unit for printing, a printing unit capable of printing a special color (for example, gold or the like) can be used.

  In the above-described embodiment, an example in which the sheet edge is adopted as the sheet reference position is illustrated. However, as the sheet reference position, as illustrated in FIGS. 8 (corresponding to FIG. 3) and FIG. 9 (corresponding to FIG. 7), A mark mb that has been subjected to print processing (not limited to thermal transfer printing) on the back surface of the paper S by the back surface print head 31B may be applied (first modification). In FIGS. 8 and 9, the same reference numerals are given to the portions corresponding to FIGS. 3 and 7, respectively. The back surface print head 31B belongs to, for example, the back surface print unit 3B having a configuration according to each of the print units 3 described above (the print unit 3 that performs print processing on the front surface of the paper S). The back surface print unit 3B is arranged on the most upstream side, the mark mb is printed by the back surface print head 31B on the back surface of the paper S that has reached the back surface print unit 3B, and then the print units 3 (Y unit 3Y, When marks (Y mark m1, M mark m2, C mark m3) are printed by each head (Y head 31Y, M head 31M, C head 31C) of M head 31M, C unit 3C), as shown in FIG. It becomes possible to specify the relative position between the back surface mark mb and each mark (Y mark m1, M mark m2, C mark m3), and each thermal head (Y head 31Y, M head 31M, C head 31C) with respect to the sheet S. ) In the width direction can be specified. With such a printer 1, the paper reference position can be formed on the paper S by using the back surface print head 31B capable of performing printing processing on the back surface of the paper S, printing information, a destination, and the like. is there.

  Further, in the printer described in the above-described embodiment and the first modification, the detection unit is disposed in the print unit on the upstream side in the paper transport direction from the thermal head. However, the detection unit is disposed in the print unit. May be set downstream of the thermal head in the paper conveyance direction. When such a layout is adopted, the paper reference position and the mark printed by the thermal head of the print unit disposed on the upstream side are detected by the detection unit of the print unit disposed on the relatively downstream side. In addition, it is also possible to detect marks printed by the thermal head of the print unit (print unit arranged relatively downstream), and the relative positional relationship between the paper and the thermal head of each print unit Can be grasped accurately.

  Further, in a multi-head type printer in which a plurality of print units are arranged in the paper conveyance direction, a detection unit is provided corresponding to at least the most downstream print unit without providing a detection unit corresponding to all the print units. The detection unit detects the paper reference position and a mark printed by the thermal heads of all print units, or is arranged upstream of the print unit (the most downstream print unit) having the paper reference position and the detection unit. You may set so that the mark printed by the thermal head of the printing unit may be detected.

  Also, as shown in FIGS. 7 and 9, the marks printed by the thermal heads can be set so that they do not overlap on the paper if the thermal head assembly position is the normal assembly position. Although it is preferable, the marks to be printed by the thermal heads can be set so as to overlap on the paper if the assembly positions of the thermal heads are normal assembly positions. In this case, the control unit determines whether or not the marks detected by the detection unit overlap each other, and if they do not overlap, specifies which color of the mark does not overlap, Thermal heads that are not assembled in position can be identified.

  Further, in the above-described embodiment and the first modification, a multi-head type printer in which a plurality of thermal heads are arranged in the sheet conveyance direction is illustrated. However, as shown in FIG. 10 (corresponding to FIG. 1), one thermal head is used. A single head type printer including a head may be used (second modification). In FIG. 10, the same reference numerals are given to the portions corresponding to FIG. In the printer 1, an ink ribbon 33 in which a plurality of colors of ink are applied at predetermined pitches in the longitudinal direction is applied so that a single thermal head 31 can perform color print processing. Then, the printer 1 prints a color (for example, yellow) which is the thermal head 31 while sending the paper S toward the paper discharge port 4 (in the direction of arrow A in FIG. 10), and then only the print processing. The paper S is temporarily returned to the paper feed unit 2 side (in the direction of arrow B in FIG. 10), and the print process of the next ink color (for example, magenta) is performed by the thermal head 31 while being fed again toward the paper discharge port 4 side. The operation is repeated according to the number of ink colors (which may include ink for forming an overcoat layer), and the paper S on which all ink colors have been printed is cut into a predetermined size by the cut unit 5 and the paper discharge port 4 It is what is discharged from. In such a printer 1, the detection unit 34 is disposed upstream of the thermal head 31 in the paper transport direction (transport direction A during print processing), and the thermal head 31 is transported toward the paper discharge port 4 side. After the mark is printed with an arbitrary ink color (for example, yellow) by the thermal head 31 on the passing paper S or before the mark is printed, the detection unit 34 detects the paper reference position, and the arbitrary ink color is used. When the paper S is sent back to the paper feeding unit 2 after the printing process, the detection unit 34 detects the mark, and the control unit detects the relative position of the thermal head 31 with respect to the paper S based on the detected paper reference position and mark ( The amount of misalignment) is specified, and the print position by the thermal head 31 is compensated based on the relative position (deviation amount) of the identified thermal head 31. It suffices to be. Note that the printer may be configured such that the paper conveyance direction during the printing process is set to return the paper to the paper feeding unit, and the paper conveyance direction other than during the printing process is set to the direction of sending the paper to the paper discharge port side. .

  Thus, when the printer of the present invention is applied to a single head type printer, the print position (print processing area) by a single thermal head is prevented from shifting in the paper width direction, and the normal print position is set. The printing process can be suitably performed. A detection unit is arranged downstream of the thermal head in the paper transport direction (transport direction A during print processing), and the detection unit detects the paper reference position and the mark printed by the thermal head. Also good. In particular, in the case of a printer that performs a single color print process with a single thermal head, the process of feeding back the paper is unnecessary. Therefore, a detection unit is arranged downstream of the thermal head in the paper transport direction. The sheet reference position and the mark printed by the thermal head may be set to be detected.

  In the above-described embodiments and modifications, the control unit exemplifies a mode in which the print position by the thermal head is corrected based on the specified relative position of the thermal head. The position of the thermal head itself in the printer may be corrected based on the position.

  In addition, the detection unit may be disposed at a position facing a surface (a front surface of the paper in the above-described embodiment) on which a print process is performed by the thermal head. Furthermore, it is also possible to arrange the detection unit and the thermal head independently without unitizing them.

  In addition, a mark other than a straight line, for example, a figure such as a circle or a polygon, a character, a symbol, or the like is applied as a head position detection mark, or a hole or a slit formed in a sheet is applied as a sheet reference position. Can do.

  Further, the print unit may be one in which the feed roller and the pinch roller are arranged only on either the downstream side or the upstream side in the paper transport direction from the thermal head.

  In addition to a thermal printer that sublimates ink, a thermal printer that melts ink may be used.

  Further, as the paper, instead of the paper wound in a roll shape, a card-like one can be applied, or a thermal paper in which a color developing agent that causes a chemical reaction when heated can be applied. . When thermal paper is applied as the paper, a printer without an ink ribbon may be used.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

1 ... Printer 3 (3Y, 3M, 3C, 3L) ... Print unit (Y unit, M unit, C unit, L unit)
31 (31Y, 31M, 31C, 31L) ... thermal head (Y head, M head, C head, L head)
34 (34Y, 34M, 34C, 34L) ... detection unit S ... paper Se ... paper reference position (paper edge)
m1, m2, m3... head position detection marks (Y mark, M mark, C mark)

Claims (4)

A printer including at least one thermal head having a plurality of heating elements arranged in the width direction of a sheet to be printed, and a control unit that controls thermal transfer printing processing by the one or more thermal heads. There,
A head position detection mark subjected to thermal transfer printing with the at least one thermal head, and at least one detection unit for detecting a reference position of the paper;
The control unit specifies a relative position of the one or more thermal heads with respect to the paper based on the head position detection mark and the paper reference position detected by the detection unit, and the specified one or more thermal heads A printer which corrects a printing position by the thermal head or a position of the thermal head itself based on a relative position of the head. The head position detection mark that is formed by arranging a plurality of print units each including at least the thermal head and the detection unit in the paper transport direction and performing thermal transfer printing with the thermal head of the print unit disposed on the relatively upstream side. The printer according to claim 1, wherein the printer is configured to be detected by the detection unit of the print unit disposed relatively downstream. The thermal transfer printing process is performed on one surface of the sheet by the thermal head, and the detection unit is disposed at a position facing the other surface of the sheet. Printer. Further comprising a back surface print head for performing print processing on the back surface of the paper upstream of the thermal head,
4. The printer according to claim 1, wherein the sheet reference position is a mark printed by the back surface printing head.

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