JP2005096168A - Head cleaning method and thermal printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply remove stains of a thermal head without using a cleaning sheet. <P>SOLUTION: The thermal printer feeds a recording paper 3 in a printing direction by a capstan roller 5 and performs thermal recording on the recording paper 3 supported by a platen roller 11 by the heating element array 12 of a thermal head 6. The thermal recording is performed by developing thermal coloring layers of yellow, magenta and cyan colors. Immediately after thermal recording of yellow, magenta and cyan, by making fixing lamps 21 and 22 emit light, the thermal developing layers of yellow and magenta are fixed. When the recording paper is fed in the direction opposite to the printing direction after the thermal recording of cyan, the recording paper 3 is pinched and transported by the heating element array 12 and the platen roller 11. The pinching transport makes a pressure distribution on the heating element array opposite to that during thermal recording, applies a higher pressure to a site to which stains adheres and removes the stains. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a head cleaning method and a thermal printer.

  Some color thermal printers print a full color image by three-color surface sequential recording by heating on a thermal head while conveying color thermal recording paper. In color thermal recording paper, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, a yellow thermosensitive coloring layer, and a transparent protective layer are sequentially formed on a support. These color development layers have different color development sensitivities depending on the depth of each color development layer, and are designed to develop color with different color development thermal energy. The thermal head performs thermal recording by increasing the coloring thermal energy applied in the order of the yellow thermal coloring layer, the magenta thermal coloring layer, and the cyan thermal coloring layer, and forms yellow, magenta, and cyan images sequentially. Note that after thermally recording the yellow image and the magenta image, a light fixing process is performed to decompose the uncolored components.

  During thermal recording of the cyan thermosensitive recording layer, the coloring heat energy becomes the largest. Thereby, the components of the transparent protective layer are softened and adhere as dirt on the thermal head. This dirt may burn and stick as it is.

  Dirt adhering to the thermal head causes problems such as deterioration of print image quality by inhibiting heat transfer from the thermal head to the recording paper, and thus the thermal head is cleaned (for example, patent documents). 1 and 2).

  In Patent Document 1, a cleaning member is disposed at a portion facing the thermal head outside the recording range so that the surface of the thermal head is in sliding contact. Dirt is removed by moving the thermal head and bringing it into contact with the cleaning member. Patent Document 2 relates to a thermal transfer printer that transfers ink on an ink ribbon onto a recording sheet by controlling the temperature of a thermal head to heat the ink ribbon. A cleaning sheet is prepared instead of the ink ribbon, and the cleaning sheet and the thermal head are brought into contact with each other to remove dirt.

JP-A-10-109445 Japanese Patent Laid-Open No. 10-839

  However, in Patent Document 1, since only the thermal head and the cleaning member are brought into contact with each other and no pressure is applied to the contact surface from the normal direction, only dirt with weak adhesion can be removed. In Patent Document 2, it is necessary to prepare a dedicated cleaning sheet, which imposes an economic burden on the user. In addition, the cleaning sheet must be set in the printer, and extra effort is put on the user.

  The present invention has been made in consideration of the above-described problems, and provides a head cleaning method and a thermal printer that can reliably remove the contamination of the thermal head without burdening the user with labor and cost. Objective.

  The present invention feeds a recording material provided with a plurality of heat-sensitive coloring layers that emit different colors, and the recording material is sandwiched between a heating element and a platen member during the feeding to perform thermal recording by the heating element. The present invention relates to a head cleaning method for a thermal printer. The recording material is pressed against the heating element by the platen member when the recording material is fed in the opposite direction to the thermal recording by the heating element of the thermal head.

  When feeding the recording material in the direction opposite to that during thermal recording, the pressing of the recording material to the heating element is preferably performed when feeding the recording paper or immediately after recording of the thermosensitive coloring layer having low coloring sensitivity, Further, it is preferable to carry out every predetermined number of prints. When the predetermined number of sheets is set to one sheet, for each printing range in which the recording material is formed by a cut sheet for each sheet, and when the recording material is formed by a roll sheet, the sheet is cut for one sheet when cut. It is good to do. In addition, when the predetermined number of sheets is set to a plurality of sheets, when the recording material is formed by a cut sheet, the printing range becomes a plurality of sheets when the recording material is formed by a roll sheet and when the recording material is formed by a roll sheet. It is good to carry out every time or every roll sheet exchange.

  The present invention relates to a thermal printer that feeds a recording material provided with a thermosensitive coloring layer, and that records the recording material between a heating element of a thermal head and a platen member during the feeding and performs thermal recording with the heating element. . Means for feeding the recording material in a direction opposite to that during thermal recording by the heating element of the thermal head, and pressing means for pressing the recording paper against the heating element by the platen member during feeding of the recording paper by the feeding means. Features.

  The thermal printer includes a rotation control unit that rotates a platen member, and the rotation control unit is used during recording paper feeding by the feeding unit.

  According to the present invention, when the recording material is fed in the opposite direction to that during thermal recording, the recording material is pressed against the heating element of the thermal head by the platen member, so that the pressure distribution on the heating element is in the opposite direction to that during thermal recording. When the feed is reversed and high pressure is also applied to the soiled part, the dirt on the heating element is surely removed. Since this cleaning operation does not require a cleaning sheet, it does not put extra labor or economic burden on the user.

  If the cleaning operation is performed when the recording paper is fed, the head cleaning is always performed, and printing with less image quality deterioration is possible. Further, if it is performed immediately after recording of the thermosensitive coloring layer having a low coloring sensitivity, dirt on the heating element is removed immediately after adhering, so that efficient head cleaning becomes possible.

  The cleaning operation is performed for each predetermined number of prints. For example, when the predetermined number of sheets is set to one, the dirt is removed immediately after adhering, and it is not necessary to use an extra sheet for cleaning. For example, when the predetermined number of sheets is set to a plurality of sheets, the number of cleaning operations can be reduced, and the printing time can be shortened.

  By using a pressing unit that presses the recording paper against the heating element by the platen member and a rotation control unit that rotates the platen member, a cleaning operation can be performed. During the thermal recording, the rotation control means is not used and the platen member is left free. Thus, an unstable tension is not applied to the recording material during thermal recording, and the occurrence of color misregistration can be suppressed.

  As shown in FIG. 1, the thermal printer 2 is provided with a recording paper roll 4 in which a long color thermal recording paper 3 is wound in a roll shape. The capstan roller 5 conveys the color thermal recording paper 3 toward the thermal head 6 by rotating in the forward direction, and conveys the color thermal recording paper 3 toward the recording paper roll 4 by rotating in the reverse direction. Hereinafter, the conveyance direction toward the thermal head 6 is referred to as a paper feeding direction, and the conveyance direction toward the recording paper roll 4 is referred to as a printing direction because printing is performed simultaneously with conveyance.

  A thermal head 6 is provided on the conveyance path 10 of the color thermal recording paper 3, and a platen roller 11 is provided to face the thermal head 6. The thermal head 6 includes a heating element array 12 in which a large number of heating elements are arranged in a line along the main scanning direction. Heat is applied to the color thermal recording paper 3 by the heating element array 12. The thermal head 6 moves between a printing position where the color thermal recording paper 3 is pressed against the peripheral surface of the platen roller 11 and a retracted position away from the peripheral surface of the platen roller 11. By moving the thermal head 6 to the printing position, the color thermal recording paper 3 can be pressed from both sides by the platen roller 11 and the heating element array 12.

  Instead of moving the thermal head 6, a platen roller 11, which will be described later, can be moved so that the peripheral surface of the platen roller 11 is in contact with the color thermal recording paper 3 and a position away from the color thermal recording paper 3. May be moved.

  The platen roller 11 is provided with a gear 13. When the pulse motor 14 is driven by a system controller (not shown), the driving force is transmitted through the gears 15 and 16 and is transmitted to the gear 13 so that the platen roller 11 is rotated. The gear 16 moves between a driving position where the driving force is transmitted to the platen roller 11 and a retracted position where the driving force is not transmitted. These positions are represented by a solid line and a broken line in the figure, respectively. The platen roller 11 is driven by the rotation control means as described above.

  An optical fixing device 20 is provided downstream of the thermal head 6 in the paper feeding direction. The optical fixing device 20 includes a yellow fixing lamp 21 and a magenta fixing lamp 22. The yellow fixing lamp 21 emits near-ultraviolet light having a wavelength peak around 420 nm. The magenta fixing lamp 22 emits ultraviolet light having a wavelength peak near 365 nm.

  As shown in FIG. 2, the color thermosensitive recording paper 3 is composed of a support 23, a cyan thermosensitive coloring layer 25, a magenta coloring layer 26, a yellow thermosensitive coloring layer 27, and a transparent protective layer 28 formed on the support. . Each coloring layer is designed to develop a color when a predetermined coloring thermal energy is applied. As shown in FIG. 3, the color development heat energy required for color development varies depending on the color development layer. The yellow heat-sensitive color development layer 27 develops color with the smallest color development heat energy, and the cyan heat-sensitive color development layer 25 produces color with the largest color development heat energy. To do. Further, the yellow thermosensitive coloring layer 27 loses the coloring ability of the uncolored portion by irradiation of the yellow fixing lamp 21. Similarly, the magenta thermosensitive coloring layer 26 loses the coloring ability of the uncolored portion by irradiation of the magenta fixing lamp 22.

  As shown in FIG. 1, a paper discharge roller 32, a cutting mechanism 33, and a discharge port 34 are provided on the downstream side in the paper feeding direction with respect to the optical fixing device 20. The paper discharge roller 32 conveys the color thermal recording paper 3 to the discharge port 34 during paper discharge. The cutting mechanism 33 cuts the color thermal recording paper 3 into a predetermined size.

  Hereinafter, the operation of the above configuration will be described with reference to the flowchart shown in FIG. When an instruction to start printing is issued by a system controller (not shown), the capstan roller 5 rotates forward and the color thermal recording paper 3 is conveyed in the paper feeding direction. The conveyance is continued until the printing range passes the contact position with the platen roller 11. During the conveyance, the thermal head 6 is moved to the retracted position. The platen roller 11 is in a free state because the gear 16 has moved to the retracted position. The above is the paper feeding operation.

  When the paper feeding operation is completed, the thermal head 6 moves to the printing position, and the heating element array 12 contacts the color thermal recording paper 3. When the capstan roller 5 rotates in the reverse direction, the color thermal recording paper 3 is conveyed in the printing direction while being sandwiched between the heating element array 12 and the platen roller 11. The thermal head 6 is driven in accordance with this conveyance, and the yellow thermosensitive coloring layer 27 of the color thermosensitive recording paper 3 is colored one line at a time. Here, the platen roller 11 is in a free state, and only the capstan roller applies tension to the color thermal recording paper. When the printing range passes the contact position with the platen roller 11, the capstan roller 5 stops rotating. The thermal head 6 also stops driving. Finally, a yellow image is recorded in the printing range of the color thermal recording paper 3. The above is the yellow printing operation.

  When the yellow printing operation is finished, the thermal head 6 moves to the retracted position. When the capstan roller 5 rotates forward, the color thermal recording paper 3 is conveyed in the paper feeding direction. When the printing range passes through the yellow fixing lamp 21, the yellow fixing lamp 21 is turned on to lightly fix the yellow image. When light fixing is performed on the entire printing range, the yellow fixing lamp 21 is turned off. The capstan roller 5 stops rotating. The above is the yellow light fixing operation.

  The magenta printing operation and the magenta light fixing operation are performed in the same manner as the yellow printing operation and the yellow light fixing operation. However, during the magenta light fixing operation, the magenta fixing lamp 22 is used instead of the yellow fixing lamp 21.

  The cyan printing operation is performed in the same manner as the yellow printing operation. During the cyan printing operation, the heating element array 12 becomes the highest temperature, and the components of the transparent protective layer 28 may soften and adhere to the heating element array as dirt. As shown in FIGS. 5A and 5B, dirt is likely to adhere to the downstream side in the printing direction (upstream side in the paper feeding direction) where the pressure is weakened. Note that the cyan image is not subjected to light fixing because it is unlikely to be exposed to a high temperature again.

  After completing the cyan printing operation, the thermal head 6 does not move to the retracted position but is in the printing position. The gear 16 moves from the retracted position to the driving position, so that the platen roller 11 can be driven.

  When these preparations are completed, the capstan roller 5 and the platen roller 11 rotate forward. The color thermal recording paper 3 is conveyed in the paper feeding direction while being pressed on both sides by the heating element array 12 and the platen roller of the thermal head 6. In this state, since the pressure distribution is opposite to that in FIG. 5B, a relatively high pressure is applied to the upstream side in the paper feeding direction (downstream in the printing direction) on the heating element array, and the stain is applied to the color thermal recording paper. Adhere to. In this way, cleaning for removing dirt from the thermal head 6 is performed. At the time of cleaning, the thermal head 6 is not driven, but may be driven at a temperature at which the cyan thermosensitive coloring layer does not develop color.

  The color thermal recording paper 3 is conveyed until the printing range passes the cutting position. During this conveyance, the paper discharge roller 32 is also driven. Cleaning may be performed throughout the conveyance, or may be performed by selecting an arbitrary time during the conveyance. When selecting an arbitrary time, the cleaning is completed by moving the thermal head 6 to the retracted position. The above is the cleaning operation.

  When the conveyance is stopped, the thermal head 6 stops driving and moves to the retracted position. Further, the gear 16 also moves to the retracted position, and the platen roller 11 becomes free. The color thermal recording paper 3 is divided by the cutting mechanism 33 at the boundary between the printing range where all printing has been completed and the range where printing has not been completed. Of the color thermal recording paper, the portion having the print range where all the prints have been completed is discharged from the discharge port. The above is the cutting operation and the paper discharge operation.

  One series of printing is completed by a series of these operations. When printing is continued, the operation after the yellow printing operation is repeated.

  In the above-described embodiment, the cleaning operation is performed for each print. However, the cleaning operation may be performed for each of a plurality of prints, or when the recording paper roll is replaced or when the user is arbitrarily set. In these cases, since it is assumed that a relatively large amount of dirt is attached on the heating element array of the thermal head 6, the color thermal recording paper 3 used for the cleaning operation may be cut and discharged. For example, when the cleaning operation is performed for each of a plurality of prints, the operation flow is as shown in the flowchart of FIG. The counter in the flowchart calculates the number of prints in response to a signal from a photo sensor or the like provided on the conveyance path.

  The removed dirt adheres to the color thermosensitive recording paper 3, but it may be captured by an adhesive roller or the like. Further, instead of or in addition to the adhesive roller, a suction mechanism may be provided to suck dirt.

  In the above embodiment, roll paper is used as the color thermal recording paper. However, cut paper that has been cut in advance for each printing range may be used.

  In the above embodiment, the gear mechanism having the gear 16 that moves between the drive position and the retracted position is used for switching between rotating the platen roller 11 and making it free. Instead of this, as shown in FIG. 7, a rotatable roller 38 that moves between a driving position where the platen roller 11 is in contact with the peripheral surface and a retracted position away from the peripheral surface of the platen roller 11 may be used. Other known mechanisms may also be used.

  In the above embodiment, the color thermosensitive recording paper 3 is conveyed by the capstan roller 5 and the platen roller 11 during the cleaning operation. Alternatively, the color thermosensitive recording paper 3 may be conveyed by the capstan roller 5 and the paper discharge roller 32. Good. In this case, the cleaning operation can be performed without rotating the platen roller 11, and it is not necessary to prepare a mechanism for driving the platen roller 11.

  In the above-described embodiment, the cleaning operation is performed after the cyan printing operation and before the cutting / discharging operation. However, the cleaning operation may be performed during the yellow light fixing operation, the magenta light fixing operation, the paper feeding operation, and the like.

  In the above embodiment, the optical fixing device 20 is provided on the downstream side in the paper feeding direction with respect to the thermal head 6, but may be provided on the upstream side in the paper feeding direction with respect to the thermal head 6. In this case, the yellow printing operation and the yellow light fixing operation, and the magenta printing operation and the magenta light fixing operation are performed almost simultaneously.

It is the schematic of a thermal printer. It is explanatory drawing which shows the layer structure of a color thermal recording paper. It is a graph which shows the thermal sensitivity characteristic of a color thermal recording paper. It is a flowchart which shows the flow of various operation | movement when performing cleaning for every printing of 1 sheet. It is explanatory drawing which shows the adhesion state of the dirt on a heat generating element array. It is a flowchart which shows the flow of various operation | movement when performing cleaning for every printing of several sheets. It is explanatory drawing which shows the mechanism which drives the platen roller in another Example.

Explanation of symbols

2 Thermal Printer 3 Color Thermal Recording Paper 6 Thermal Head 11 Platen Roller 12 Heating Element Array 13 Gear 14 Pulse Motor 15 Gear 16 Movable Gear

Claims (5)

In a thermal printer that feeds a recording material provided with a plurality of heat-sensitive coloring layers that develop different colors, and in which the recording material is sandwiched between a heating element and a platen member of the thermal head and thermally recorded by the heating element. ,
A method for cleaning a head of a thermal printer, wherein the recording material is pressed against the heating element by a platen member when the recording material is fed in a direction opposite to that during thermal recording by the heating element of the thermal head.   2. The thermal printer head cleaning method according to claim 1, wherein the recording material is pressed against the heat generating element when the recording paper is fed or immediately after the recording of the thermal coloring layer having low coloring sensitivity.   3. The thermal printer head cleaning method according to claim 2, wherein the recording material is pressed against the heat generating element every predetermined number of prints. In a thermal printer that feeds a recording material provided with a thermosensitive coloring layer, and in which the recording material is sandwiched between a heat generating element of a thermal head and a platen member and thermally recorded by the heat generating element,
Means for feeding the recording material in a direction opposite to that during thermal recording by the heating element of the thermal head;
A thermal printer comprising pressing means for pressing the recording paper against the heating element by the platen member during feeding of the recording paper by the feeding means.   5. The thermal printer according to claim 4, further comprising a rotation control unit for rotating the platen member, wherein the rotation control unit is used during recording paper feeding by the feeding unit.

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