JP2013123885A - Thermal printer and method for cleaning thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal printer dispensing with manual cleaning work of a thermal head, and properly removing deposits possibly depositing around a heating element of the thermal head without using an exclusive cleaning ribbon and a special ink ribbon.SOLUTION: The thermal printer is provided with a cleaning function of executing both a backward feeding process of pressing the thermal head in a non-excited state to the platen side to position the thermal head at a press-contact position where the heating element contacts the ink ribbon, moving the ink ribbon by a predetermined distance to the reverse direction B of the conveying direction in thermal transfer process A, and making the deposits deposited on the upstream side in the conveying direction in thermal transfer process around the heating element depart from the heating element, and a forward feeding process of moving the ink ribbon to the conveying direction in thermal transfer process longer than the moving distance in the backward feeding process, and moving the deposits to the downstream side in the conveying direction in thermal transfer process around the heating element.

Description

  The present invention relates to a thermal printer provided with a thermal head and a method for cleaning the thermal head in the thermal printer.

  2. Description of the Related Art Conventionally, there is known a thermal printer that uses the heat of a thermal head to transfer and print sublimation ink or melt ink applied to an ink ribbon onto a sheet. In this type of thermal printer, the thermal head is pressed against the platen roller side against the paper and the ink ribbon superimposed in the thickness direction on the platen, and the thermal head is heated with the ink ribbon in close contact with the paper. Thus, a desired image or the like can be printed on the paper by thermally transferring the ink onto the paper. This type of thermal printer is set so that the thermal transfer printing process can be performed efficiently by bringing the heating element of the thermal head in an energized state into direct contact with the ink ribbon. The ink ribbon conveyed in the same direction as the paper while in contact with the heating element in the heat generation state passes between the thermal head and the platen and is then peeled off from the paper by an appropriate means and wound around the take-up ribbon core. Taken.

  By the way, in a thermal printer equipped with such a thermal head, ink ribbon waste generated when a part of the base film of the ink ribbon melts with heat from the heating element, or dust in the printer causes ink in the heating element. If unnecessary streaks appear on the paper that has been subjected to the thermal transfer printing process due to such deposits accumulated on the upstream side of the ribbon conveyance direction, the print quality naturally decreases.

  As a means for preventing such problems, there can be mentioned a mode in which the thermal head is taken out from the printer by periodic maintenance and deposits are removed using a cotton swab or cloth, but such work is troublesome. There is also a risk of damage to the therma head itself if it is not done carefully and carefully.

  Therefore, for example, a cleaning ribbon is used in place of the ink ribbon, and the cleaning head and the paper are conveyed while the cleaning ribbon and the paper are sandwiched between the thermal head and the platen roller, thereby cleaning the thermal head. When the foreign matter removing part passes through the thermal head using the ink ribbon in which the foreign matter removing part for removing the deposit on the thermal head is formed at predetermined intervals, the thermal head is used in the foreign matter removing part. A mode (for example, Patent Document 2) for removing the attached matter is considered.

JP-A-2005-212251 JP 2008-246905 A

  However, the ribbon for exclusive use for cleaning as described above and the special ink ribbon formed with the foreign substance removing portion are disadvantageous in that the manufacturing cost is higher than that of a normal ink ribbon, and it takes time and effort for the user. End up.

  The present invention has been made paying attention to such problems, and the main purpose is that manual thermal head cleaning work is unnecessary, and without applying a dedicated cleaning ribbon or special ink ribbon, It is an object of the present invention to provide a thermal printer and a thermal head cleaning method capable of suitably removing deposits that can accumulate around the heating element of the thermal head.

  That is, according to the present invention, with the ink ribbon and the paper superimposed on the platen in the thickness direction, the thermal head is pressed against the platen side, and the surface of the ink ribbon that contacts the paper by the heat from the heating element of the thermal head. The present invention relates to a thermal printer that can thermally transfer a formed thermal transfer layer to a sheet. Here, the platen may be either configured using a rotatable roller or configured using a plate. The “thermal transfer layer” of the present invention is not only a layer using a dye (ink) such as yellow, magenta, cyan, and black, but also a layer using a material that contributes to improving the quality of a print screen (such as a protective layer or Includes specially processed layers). In addition, “deposits” include dust in the printer, or a part of the ink ribbon that has been released from the integrity of the ink ribbon (for example, anti-friction melted by the heat of the heating element). And a back material such as a material, or a material peeled off from an ink ribbon by friction with a heating element).

  In the thermal printer of the present invention, the thermal head in a non-energized state is pressed to the platen side to be positioned at a pressure contact position where the heating element contacts the ink ribbon, and the ink ribbon is transported in the thermal transfer process (hereinafter, A reverse feeding process in which the deposit accumulated on the upstream side of the heating direction of the ink ribbon in the heat transfer process is moved away from the heating element by moving a predetermined distance in the opposite direction to the "transfer direction during the thermal transfer process"); Cleaning function that moves the ink ribbon in the transport direction during the thermal transfer process longer than the distance traveled during the reverse transfer process, and moves the deposit to the downstream side in the transport direction during the thermal transfer process of the ink ribbon. It is characterized by having.

  As described above, in the printer of the present invention, the thermal transfer process in the heating element of the thermal head at the time before the reverse feeding process is performed by positioning the non-energized thermal head at the pressure contact position and performing the reverse feeding process in that state. Deposits that may exist on the upstream side in the transport direction can be forcibly separated from the heating element, and if forward feeding is performed in this state, the ink ribbon is moved longer than the distance traveled during reverse feeding during thermal transfer processing. As the ink ribbon is moved, the above-described deposit can be moved further to the downstream side in the conveyance direction during the thermal transfer process than the heating element. In the thermal printer of the present invention, since the thermal head is set in a non-energized state at the time of reverse feeding processing and normal feeding processing, for example, even if the ink ribbon contains an antifriction material or the like, In addition, the antifriction material and the like are not melted by the heat from the heating element and adhered to the heating element during the forward feeding process.

  Therefore, the thermal printer of the present invention starts the cleaning process by temporarily moving the ink ribbon in the direction opposite to the conveyance direction during thermal transfer and then moving the ink ribbon in the conveyance direction during thermal transfer longer than the reverse feed distance. Prior to this, deposits that may exist on the upstream side in the thermal transfer conveyance direction of the heating element of the thermal head can be forcibly moved to the downstream side in the thermal transfer conveyance direction from the heating element. Therefore, compared with the mode in which the user accesses the printer directly and cleans the thermal head, it does not require precise work, and in comparison with the mode in which a dedicated cleaning ribbon or special ink ribbon is used. Thus, it is possible to reduce the cost required for the cleaning process of the head to obtain the therma.

  In the thermal head cleaning method of the present invention, the ink ribbon and paper are superposed in the thickness direction on the platen, the thermal head is pressed against the platen side, and the heat from the heating element of the thermal head is used to heat the ink ribbon. Thermal head that removes deposits accumulated on the upstream side in the transport direction during thermal transfer processing of the ink ribbon of the thermal head heating element in a thermal printer that can thermally transfer the thermal transfer layer formed on the surface in contact with the paper to the paper. The present invention relates to a cleaning method.

  In the thermal head cleaning method of the present invention, the thermal head in a non-energized state is pressed to the platen side so as to be positioned at a pressure contact position where the heating element contacts the ink ribbon, and the ink ribbon is conveyed during the thermal transfer process. Next to the reverse feed processing step, the deposit is moved away from the heating element by moving a predetermined distance in the direction opposite to the direction, and the deposit accumulated on the upstream side in the transport direction during the thermal transfer process of the ink ribbon in the heating element, The ink ribbon is moved in the transport direction during the thermal transfer process longer than the moving distance during the reverse feed process, and the deposit is moved to the downstream side in the transport direction during the thermal transfer process of the ink ribbon in the heating element. It is characterized by. Here, the “platen” and “thermal transfer layer” in the present invention have the same meanings as those mentioned in the above thermal printer.

  With such a thermal head cleaning method, the thermal head is de-energized and the ink ribbon is conveyed in the forward and reverse directions according to the above-described procedure. No cleaning work is required, deposits can be removed from the vicinity of the heating element without incurring a significant increase in cost, and deterioration in print quality due to the presence of deposits can be prevented / suppressed.

  According to the present invention, by temporarily moving the ink ribbon in the direction opposite to the conveyance direction during thermal transfer, and then moving the ink ribbon in the conveyance direction during thermal transfer longer than the reverse feed distance, the ink ribbon before the cleaning process is started. At this point, deposits that may exist on the upstream side in the thermal transfer conveyance direction of the thermal head heating element can be forcibly moved downstream of the heating element in the thermal transfer conveyance direction, eliminating the need for manual cleaning of the thermal head. It is possible to provide a thermal printer and a thermal head cleaning method capable of suitably removing deposits that can accumulate around the heating element of the thermal head without applying a dedicated cleaning ribbon or special ink ribbon. it can.

1 is a schematic diagram of the overall configuration of a thermal printer according to an embodiment of the present invention. The principal part enlarged view of FIG. The figure which shows the state in which the deposit exists in the heat generating body periphery in the thermal printer which concerns on the embodiment corresponding to FIG. 9 is a flowchart of thermal head cleaning processing in the embodiment. The figure which shows the state at the time of completion | finish of a reverse feed process in the thermal printer which concerns on the embodiment corresponding to FIG. FIG. 3 is a diagram showing a state during normal feeding processing in the thermal printer according to the embodiment corresponding to FIG. 2. FIG. 4 is a view corresponding to FIG. 4, showing a relationship between a thermal head cleaning process and a thermal transfer print process in the embodiment. FIG. 5 is a view corresponding to FIG. 4 showing another relationship between the thermal head cleaning process and the thermal transfer print process in the embodiment.

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

  As shown in FIG. 1, the printer P according to the present embodiment can press-contact each other in a state where the ink ribbon R in which thermal transferable ink is stuck (laminated) on the ribbon (base film) is stacked on the paper S. This is a thermal printer capable of printing a desired image or the like by thermally transferring the ink on the ink ribbon R onto the paper S by passing between the thermal head 21 and the platen 22 that are arranged to face each other.

  In the ink ribbon R applied in the present embodiment, an ink coating layer (corresponding to the “thermal transfer layer” of the present invention) is formed on the surface that can be in close contact with the paper S, and an antifriction material is applied on the surface that can contact the thermal head 21. It is set to a slip surface that can be included to exhibit the function of reducing the frictional resistance of the thermal head 21. The ink ribbon R is obtained by applying, for example, yellow, magenta, and cyan inks to a long base film, and each color ink is formed using a dye that sublimes by heat.

  As shown in FIG. 1, the thermal printer P includes a paper feed unit 1, a printing unit 2 that performs thermal transfer printing on the surface of the paper S supplied from the paper feed unit 1, and a discharge having a discharge port 31. Unit 3, a paper transport mechanism 4 that transports paper S along a paper transport path W (transport path) formed between paper feed unit 1 and discharge unit 3, and printing unit 2 on paper transport path W. And a transverse cutting portion 5 that is disposed closer to the discharge port 31 and can cut the sheet S in the sheet width direction. In this thermal printer P, at least the paper feeding unit 1, the printing unit 2, the paper transport mechanism 4 and the horizontal cutting unit 5 are provided in a common housing, and the discharge port 31 and the discharge tray 32 constituting the discharge unit 3 are provided in the housing. It is configured to be exposed outside the body.

  The paper feed unit 1 can accommodate the paper S wound in a roll shape with the surface (printing surface) to be thermally transferred facing inward.

  As shown in FIG. 1, the sheet transport mechanism 4 that transports the sheet S between the sheet feeding unit 1 and the discharge unit 3 is sequentially arranged from the sheet feeding unit 1 side to the discharge unit 3 side, for example. The sheet feeding side feed roller 41 and the first pinch roller 42, the feed roller 43 and the second pinch roller 44, and the discharge side feed roller 45 are used. It should be noted that the number of rollers themselves, or the number of rollers and pinch rollers, and the location of the rollers can be set as appropriate according to the specifications.

  As shown in FIGS. 1 and 2, the printing unit 2 is disposed at a position facing the thermal head 21 and the thermal head 21 and sandwiches the paper S between the thermal head 21 and functions as the paper transport mechanism 4. The platen 22 that bears a part, the ink ribbon transport mechanism 23 that transports the ink ribbon R between the thermal head 21 and the platen 22, and the thermal head 21 and the platen 22 are passed between and in close contact with each other. A separation unit 24 that separates a certain sheet S and the ink ribbon R is provided.

  The thermal head 21 is provided with a heating element 21a in a portion that can be directly pressed against the platen 22, and a head down position (the position of the thermal head 21 shown in FIGS. 1 and 2) that can be pressed against the platen 22 by the control unit. And a position corresponding to the “pressure contact position” of the present invention) and a head-up position (not shown) that is separated from the platen 22 and the heating element 21a cannot contact the ink ribbon R. Has been. A position where the heating element 21a of the thermal head 21 positioned at the head down position contacts the platen 22 is a thermal transfer position P1 where the ink ribbon R is thermally transferred to the paper S. In this embodiment, a platen roller that can rotate in the forward and reverse directions in synchronization with the rotation operation of the feed roller 43 is applied as the platen 22. In FIG. 2, for convenience of explanation, the heating element 21 a having a sharp tip is shown. However, in actuality, the contact surface with the ink ribbon R is increased, or the ink ribbon R and the paper S are pressed against each other. It is possible to use a heating element 21a whose tip is set in a partial arc shape in cross section so as not to be scratched. Of course, the printer P of the present invention does not exclude a mode in which the heating element 21a having a sharp tip is applied.

  The ink ribbon transport mechanism 23 also supplies a supply-side ribbon core 231 that can be held in a state where the ink ribbon R is wound in a roll shape, and the ink ribbon R that is wound around the supply-side ribbon core 231 to a paper transport path W (transport path). ) And the above-described thermal transfer position P1 (the thermal head 21 and the platen roller 22) in the transport direction A of the paper S during the thermal transfer process (hereinafter referred to as “the transport direction A during the thermal transfer process”). A winding side ribbon core 233 which is disposed downstream of the pressure contact position) and can hold the ink ribbon R subjected to the thermal transfer process in a wound state, and the ink ribbon R toward the winding side ribbon core 233. A take-up guide roller 234 is provided.

  The ink ribbon transport mechanism 23 causes the ink ribbon R to be unwound from the supply-side ribbon core 231 and guided toward the paper transport path W by the feeding guide roller 232 during the thermal transfer printing process, and is in close contact with the paper S. In this state, after passing through the thermal transfer position P1, it is peeled off from the paper S by passing through a peeling portion 24 described below, and is conveyed as it is toward the winding-side ribbon core 233 by the winding guide roller 234. It is wound around the side ribbon core 233. In the present embodiment, the conveyance direction A during the thermal transfer process is set to a direction opposite to the conveyance direction B from the paper feeding unit 1 toward the discharge unit 3 (this conveyance direction is referred to as “discharge conveyance direction B”). However, the printer P in which the conveyance direction A during the thermal transfer process is set to the same direction as the discharge conveyance direction B may be used.

  The peeling unit 24 is provided downstream of the thermal head 21 in the conveyance direction A during the thermal transfer process, and defines a peeling start position where the ink ribbon R that has passed between the thermal head 21 and the platen roller 22 is peeled from the paper S. Is. In the present embodiment, a peeling roller is used to press the paper S and the ink ribbon R, which overlap each other, from the ink ribbon side toward the platen roller 22 at a position downstream of the thermal transfer position P1 in the transport direction A during the thermal transfer process. The peeling part 24 is comprised. Here, the peeling unit 24 constitutes a part of the printing unit 2, but if it pays attention to the function of defining the transport path of the ink ribbon R, it constitutes a part of the ink ribbon transport mechanism 23. It can also be understood as a thing.

  As shown in FIG. 1, the discharge unit 3 includes a discharge port 31 and a discharge tray 32 that receives and stores the paper S discharged from the discharge port 31, and a desired print process is performed by the printing unit 2. The paper S can be discharged out of the housing as a cut paper (paper piece) cut into a predetermined size and placed on the discharge tray 32 in a stacked state.

  As shown in FIG. 1, the horizontal cutting unit 5 includes a first cutter 51 disposed on the printing surface side of the paper S and a second cutter 52 fixedly disposed on the back surface (non-printing surface) side of the paper S. The sheet S is cut in the width direction by sliding the first cutter 51 on the second cutter 52 and scanning in the width direction of the sheet S in accordance with the control of the control unit.

  In the printer P according to the present embodiment, the operations of the paper feeding unit 1, the printing unit 2, the discharge unit 3, the paper transport mechanism 4, and the horizontal cutting unit 5 are controlled by a control unit (not shown).

  Next, the operation and action of the thermal printer P according to this embodiment will be described with reference to FIGS.

  The thermal printer P according to the present embodiment first specifies the print size on the print surface of the paper S by the control unit based on the print pattern data input by a user operation or the like, and according to the specified print size. The paper S wound in the form of a roll in the paper feed unit 1 is sequentially passed between the paper feed side feed roller 41 and the first pinch roller 42 and between the feed roller 43 and the second pinch roller 44. Transport to the printing unit 2. In the present embodiment, as described above, the transport direction of the paper S during the thermal transfer process (the transport direction A during the thermal transfer process) is opposite to the discharge transport direction B from the paper feed unit 1 toward the discharge unit 3. Before the thermal transfer printing process is performed, it is necessary to transport the paper S to the discharge unit 3 side from the thermal transfer position P1 according to the specified print size. This conveyance process is performed with the thermal head 21 positioned at the head-up position.

  Next, the printer P according to the present embodiment moves the thermal head 21 from the head-up position to the head-down position, and sandwiches the paper S and the ink ribbon R in the thickness direction between the thermal head 21 and the platen roller 22. In this state, by transporting the paper S and the ink ribbon R in the transport direction A during the thermal transfer process by the paper transport mechanism 4, the printer P of the present embodiment is a thermal transfer position that is the pressure contact position between the thermal head 21 and the platen roller 22. At the position P1, a color image can be printed (formed) on the print surface of the paper S by sublimating yellow, magenta, and cyan inks with heat from the heating element. At this time, it is possible to perform gradation printing in which the print density level is changed by adjusting the temperature of the heating element of the thermal head 21, and it is possible to print a high-quality color image on the print surface of the paper S. It is. The temperature adjustment and operation of the heating element 31 are controlled by the control unit.

  The thermal printer P according to the present embodiment transports the ink ribbon R and the paper S that have passed through the thermal transfer position P1 after the thermal transfer printing process to the peeling unit 24 along the transport direction A during the thermal transfer process in a state of being stacked in the thickness direction. Then, the ink ribbon R that has reached the peeling portion 24 is peeled from the paper S by the pressing action of the peeling portion 24.

  The printer 1 according to the present embodiment conveys the ink ribbon R that has passed through the separation unit 24 and separated from the paper S, toward the take-up side ribbon core 233 by the take-up guide roller 234 of the ink ribbon transport mechanism 23. While being wound around the take-up ribbon core 233, the paper S that has passed through the peeling unit 24 is conveyed to the discharge unit 3 side, and the horizontal cutting unit 5 performs a horizontal cutting process. Specifically, the sheet S is cut in the sheet width direction by scanning the first cutter 51 and the second cutter 52 of the transverse cutting unit 5 arranged opposite to each other in the thickness direction of the sheet S in the sheet width direction.

  Finally, when the thermal printer P of the present embodiment finishes the horizontal cutting process by the horizontal cutting unit 5, the paper separated from the roll-shaped paper S wound in a roll shape by the paper feeding unit 1 is discharged from the discharge port 31. And is stored on the discharge tray 32.

  In the thermal printer P of the present embodiment that performs the thermal transfer printing process according to such a procedure, the reduction contained in the slip surface of the ink ribbon R by the heat from the heating element 21a of the thermal head 21 that is energized during the thermal transfer printing process. As shown in FIG. 3, it is assumed that the friction material melts and accumulates on the upstream side in the conveyance direction A during heat transfer in the heat generating element 21a. Further, not only the antifriction material, but also the wear debris of the ink ribbon R generated due to strong contact with the heating element 21a at the thermal transfer position P1, or dust in the thermal printer P is also upstream of the heating element 21a in the transport direction A during thermal transfer. It is assumed that it accumulates on the side. When the subsequent thermal transfer printing process is performed in a state where the deposit T remains accumulated, unnecessary streaks and dots appear on the print surface of the paper S, and the print quality is deteriorated. In particular, the antifriction material has a characteristic of becoming a solidified body over time, and if such a solidified body is present around the thermal head 21, unnecessary streaks and spots are likely to appear on the print surface of the paper S. .

  Therefore, the thermal printer P of the present embodiment has a cleaning function capable of removing the deposit T that can collect around the heating element 21a. In the present embodiment, a cleaning function is exhibited by controlling the operation of the printing unit 2, particularly the operation of the thermal head 21 and the ink ribbon transport mechanism 23, by a control unit (controller) provided in the printer. The control unit can store in advance operation commands to the respective units according to the following cleaning process.

  Specifically, as shown in FIGS. 4 to 6, the cleaning function includes a thermal head down process (thermal head down process step S1) for positioning the thermal head 21a at the head down position, and a thermal transfer process for the ink ribbon R. The sheet T is moved by a predetermined distance in the direction B opposite to the transport direction A, and the deposit T deposited on the upstream side in the transport direction A during the thermal transfer process of the ink ribbon R in the heat generating element 21a is separated from the heat generating element 21a (reverse) And the ink ribbon R is moved in the transport direction A during the thermal transfer process longer than the moving distance during the reverse feed process, and the deposit T is thermally transferred to the ink ribbon R in the heating element 21a. The forward feeding process (reverse feeding process step S3, see FIG. 6) for moving to the downstream side in the time conveyance direction A and the thermal head 21 from the head down position to the downstream side. Exerted by performing the thermal head-up process of moving to the windup position (thermal head up processing step S4).

  When the thermal head 21 in the non-energized state is positioned at the thermal head down position by the thermal head down process and the reverse feeding process is performed in that state, the thermal head 21 exists near the heating element 21a of the thermal head 21 before the reverse feeding process. The deposit T can be physically separated from the heating element 21a. At this time, since the thermal head 21 is in a non-energized state, there is no situation where the antifriction material contained in the ink ribbon R adheres to the heating element 21a while being melted by the heat from the heating element 21a. Further, the moving distance of the ink ribbon R during the reverse feeding process can be appropriately set as long as the deposit T can be separated from the heating element 21a to the upstream side in the transport direction A during the thermal transfer process.

  When the forward transfer process is performed in a state in which the deposit T is forcibly moved to the upstream side in the transport direction A during the thermal transfer process from the heating element 21a of the thermal head 21 by the reverse transfer process, the thermal transfer process of the ink ribbon R is performed. Accompanying movement in the transport direction A, the deposit T also moves in the same direction, and the deposit T contacts the heating element 21a when it moves in the transport direction A during the thermal transfer process by the distance of the reverse transfer process. However, when the ink ribbon R is further moved in the conveyance direction A during the thermal transfer process, the deposit T also moves downstream from the heating element 21a in the conveyance direction A during the thermal transfer process. Since the thermal head 21 is in a non-energized state even during the normal feeding process, a situation occurs in which the anti-friction material contained in the ink ribbon R adheres to the heating element 21a while being melted by the heat from the heating element 21a. In addition, the anti-friction material in the deposit T does not adhere to the heating element 21a in a molten state, and due to the slight elasticity of the ink ribbon R itself, the heating element 21a of the thermal head 21 in the press contact state Passes smoothly between the platen roller 22 and the platen roller 22. The movement distance of the ink ribbon R during the forward feeding process is such that the deposit T existing on the upstream side in the transport direction A at the time of the thermal transfer process with respect to the heating element 21a of the thermal head 21 at the start of the forward feeding process is more thermally transferred than the heating element 21a. Any distance can be set as long as the distance can be moved to the downstream side in the time conveyance direction A. The deposit T on the ink ribbon R may be collected so as to be wound around the take-up ribbon core 233 together with the ink ribbon R, or a predetermined amount of time until the take-up ribbon core 233 is reached. You may make it collect | recover by an appropriate means in a position.

  After the forward feeding process, the cleaning process can be completed by moving the thermal head 21 from the head down position to the head up position by the thermal head up process.

  As described above, the thermal printer P according to this embodiment temporarily moves the ink ribbon R in the direction opposite to the conveyance direction A during thermal transfer in a state where the thermal head 21 in the non-energized state is positioned at the head down position. By moving the ink ribbon R in the transport direction A during thermal transfer longer than the reverse feed distance, the ink ribbon R was present upstream of the heat transfer transport direction A in the heating element 21a of the thermal head 21 before the cleaning process was started. The deposit T can be forcibly moved to the downstream side in the thermal transfer conveyance direction A from the heating element 21a. Therefore, compared with the mode in which the user accesses the printer directly and cleans the thermal head, it does not require precise work, and in comparison with the mode in which a dedicated cleaning ribbon or special ink ribbon is used. Thus, the cost required for the cleaning process can be reduced. Further, the above-described cleaning process can be configured to be performed based on a predetermined operation by the user. However, if the cleaning process is automatically performed at a predetermined timing, the user is not conscious. In both cases, the thermal head cleaning process can be performed, and even when the conscious cleaning process by the user is not performed for a long period of time, a situation in which unnecessary streaks appear on the print screen due to the deposit T is avoided. Can do.

  In particular, in the thermal printer P of the present embodiment, the timing for performing the cleaning process can be set before the thermal transfer printing process or after the thermal transfer printing process. When the cleaning process is performed before thermal transfer printing, as shown in FIG. 7, after the thermal head down process (thermal head down process step), the reverse feed process (reverse feed process step), the forward feed process (normal feed process step). ) In order, and subsequently, the thermal head 21 that is not energized at this time is switched to the energized state to perform thermal transfer print processing (thermal transfer print processing step), and then thermal head up processing (thermal head up processing step). Can be set to do.

  On the other hand, when the cleaning process is performed after the thermal transfer printing, as shown in FIG. 8, the thermal head 21 is energized after the thermal head down process (thermal head down process step), and the thermal transfer print process (thermal transfer print process step). Subsequently, the thermal head is de-energized, and reverse feed processing (reverse feed processing step), forward feed processing (forward feed processing step), and thermal head up processing (thermal head up processing step) are sequentially performed. Should be set.

  The cleaning process can be performed every time the thermal transfer printing process is performed, but can be set to be performed once every several to several tens of thermal transfer printing processes. The cleaning process may be set to be performed immediately after the printer P is turned on or to be performed immediately before the printer is turned off.

  Further, in the thermal printer P of the present embodiment, the process of transporting the ink ribbon R in the transport direction A during the thermal transfer process or transporting the ink ribbon R in the direction B opposite to the transport direction A during the thermal transfer process is performed on the supply side ribbon core 231 and the winding side. This is performed based on the normal / reverse rotation of the ribbon core 233, and the normal / reverse rotation of the supply side ribbon core 231 and the take-up side ribbon core 233 is performed in synchronization with the normal / reverse rotation of the feed roller 43 of the paper transport mechanism 4. By setting, the ink ribbon R can be transported together with the paper S in the transport direction A during the thermal transfer process, or transported in the direction B opposite to the transport direction A during the thermal transfer process.

  Further, in the present embodiment, the sheet is in close contact with the sheet in a section including at least the thermal transfer printing position P1 (specifically, a section from the thermal transfer printing position P1 to the peeling position by the peeling unit 24) during the reverse feeding process and the forward feeding process. The thermal head cleaning process is performed by transporting the ink ribbon in a predetermined direction. However, since the thermal head 21 is in a non-energized state during the reverse feeding process and the forward feeding process, the ink ribbon R Is not thermally transferred to the paper S. However, there may be a case where pressure marks appear on the print surface of the paper S in the process of passing between the thermal head 21 and the platen roller 22 in the pressure contact state during the reverse feeding process and the normal feeding process. Therefore, for example, when performing borderless printing on a predetermined print screen size, the predetermined area on the upstream side of the upstream edge of the print screen size and the downstream side of the print screen size in the thermal transfer processing direction A of the paper S is usually used. The predetermined area on the downstream side of the side edge is set as a blank portion, and is finally discharged out of the printer as dust removed from the print screen. If the predetermined area of the ink ribbon R that can be in close contact with the margin portion is set as the movement distance during the reverse feeding process or the forward feeding process, the thermal head 21 is cleaned using the margin part of the paper S. It can be carried out.

  In addition, this invention is not limited to embodiment mentioned above. For example, a plate-shaped plastic template can be applied as the platen.

  Further, a thermal printer in which the conveyance direction during the thermal transfer process is set in a direction from the paper feeding unit to the discharge unit may be used. In this case, the transport direction at the time of reverse feed processing coincides with the direction from the discharge portion to the paper feed portion, and the transport direction at the time of forward feed processing coincides with the direction from the paper feed portion to the discharge portion.

  In the above-described embodiment, the ink ribbon transport mechanism is exemplified as having the take-up guide roller, but may be applied without the take-up guide roller.

  It is also possible to set so that the forward feeding process is performed in a state where the thermal head is separated from the platen and is positioned at a standby position where the heating element cannot contact the ink ribbon (head up position in the above-described embodiment). .

  Further, it is possible to perform the thermal head cleaning process in a state where no paper is set in the printer or in a state where no paper is present in the printing unit. In these cases, the reverse feeding process and the normal feeding process are performed with only the ink ribbon sandwiched between the thermal head and the platen.

  In the above-described embodiment, a printer including a control unit (controller) that controls hardware such as a printing unit for exerting a cleaning function is illustrated. However, an external device of the printer (wired or wirelessly connected to the printer) The operation of hardware such as a printing unit may be controlled based on a control command from a control unit provided in the computer.

  The printer according to the present invention may be a thermal printer that melts ink, in addition to a thermal transfer printer that sublimates ink. A thermal head cleaning function, which is a technical feature of the present invention, can also be imparted to a thermal printer capable of duplex printing.

  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.

21 ... Thermal head 21a ... Heating element 22 ... Platen (platen roller)
23: Ink ribbon transport mechanism A: Transport direction during thermal transfer process (transport direction during thermal transfer process)
P ... Thermal printer R ... Ink ribbon S ... Paper T ... Deposit

Claims (2)

With the ink ribbon and paper superimposed on the platen in the thickness direction, the thermal head is pressed to the platen side and formed on the surface of the ink ribbon that contacts the paper by the heat from the heating element of the thermal head. A thermal printer capable of thermally transferring the thermal transfer layer to the paper,
The thermal head in a non-energized state is pressed to the platen side and positioned at a pressure contact position where the heating element contacts the ink ribbon,
A reverse feed process in which the ink ribbon is moved by a predetermined distance in a direction opposite to the transport direction during the thermal transfer process, and the deposit accumulated on the upstream side of the ink ribbon in the transport direction is separated from the heat generator. ,
Cleaning in which the ink ribbon is moved in the transport direction longer than the moving distance during the reverse transport process, and the deposit is moved forward in the transport direction of the ink ribbon in the heating element. A thermal printer characterized by having a function. With the ink ribbon and paper superimposed on the platen in the thickness direction, the thermal head is pressed to the platen side and formed on the surface of the ink ribbon that contacts the paper by the heat from the heating element of the thermal head. In the thermal printer capable of thermally transferring the thermal transfer layer to the paper, the thermal head cleaning method is configured to remove deposits accumulated on the upstream side in the transport direction during thermal transfer processing of the ink ribbon on the heating element of the thermal head. And
The thermal head in a non-energized state is pressed to the platen side and positioned at a pressure contact position where the heating element contacts the ink ribbon,
A reverse feed processing step of moving the ink ribbon by a predetermined distance in a direction opposite to the transport direction at the time of thermal transfer processing, and separating the deposit accumulated on the upstream side of the ink ribbon in the transport direction from the heat generating body. When,
Subsequent to the reverse feed processing step, the ink ribbon is moved in the transport direction longer than the moving distance during the reverse feed processing, and the deposit is moved downstream in the transport direction of the ink ribbon in the heating element. A thermal head cleaning method comprising: a forward feed processing step for movement.

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