JP2012143884A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent uneven density of an output image by stably cooling a platen roller which receives heat from a thermal head during operation of a thermal transfer printer.SOLUTION: The thermal transfer printer 1 comprises a thermal head 21 which transfers an image from an ink sheet 3 to a recording paper 4 by heating the ink sheet 3 holding an ink, and a platen roller 22 which rotates while holding the recording paper 4 between the thermal head 21 and the platen roller 22. The thermal transfer printer 1 further comprises a heat radiation plate 41 which is in contact with the peripheral surface of the platen roller 22 and moves in accordance with rotation of the platen roller 22, and a main support roller 42 which abuts against the heat radiation plate 41 and supports the heat radiation plate 41 by pressing it against the platen roller 22.

Description

  The present invention relates to a thermal transfer printer including a thermal head, and more particularly to a thermal transfer printer excellent in heat dissipation performance of a thermal head.

  A thermal transfer printer includes a thermal head that sequentially heats each portion of each color ink in an ink sheet that holds a plurality of color inks, and a surface sequential that includes a platen roller that rotates while sandwiching a recording sheet between the thermal heads. Printer.

  A thermal transfer printer that uses an ink sheet that holds sublimable dye inks of a plurality of colors is referred to as a sublimation thermal transfer printer. A sublimation thermal transfer printer is known as an image forming apparatus capable of outputting a high-quality image comparable to a silver salt photograph image.

  In addition, the ink sheet holds a plurality of sublimable dye inks and a protective material, and the sublimation thermal transfer printer sequentially heats each ink portion and the protective material portion of the ink sheet, whereby the ink sheet In some cases, the image and the overcoat layer are transferred onto the recording paper in an overlapping manner. The overcoat layer is a protective layer covered with a protective material.

  By the way, the density of the image transferred to the recording paper changes depending on the thermal energy applied to the ink sheet, and the thermal head adjusts the image density by adjusting the thermal energy applied to the ink sheet. Further, since the platen roller is disposed close to the thermal head via a thin ink sheet and recording paper, the temperature is likely to fluctuate greatly depending on the heat generation state of the thermal head. The platen roller is particularly hot during continuous printing jobs in which recording paper is transported and the thermal head generates heat continuously.

  Variations in the temperature of the platen roller act as noise of thermal energy applied to the ink sheet, causing density unevenness in the output image. Therefore, in the thermal transfer printer, it is important to improve the quality of the output image by suppressing the temperature fluctuation of the platen roller by cooling the platen roller.

  For example, the printer disclosed in Patent Document 1 includes a platen roller that rotates with a heat-sensitive recording paper sandwiched between the thermal head and an auxiliary platen roller that rotates with the recording paper sandwiched between the platen rollers. . The auxiliary platen roller shown in Patent Document 1 functions as a heat radiating member that dissipates heat energy transmitted from the platen roller.

Japanese Patent Laid-Open No. 2004-108551

  However, the thermal energy of the platen roller disclosed in Patent Document 1 is transmitted to the auxiliary platen roller via the recording paper having a low thermal conductivity during the conveyance of the recording paper. For this reason, the printer disclosed in Patent Document 1 has a problem that the cooling performance of the platen roller during conveyance of the recording paper is not sufficient, and the density unevenness of the output image is not sufficiently eliminated. In particular, when a continuous print job is executed, the problem of density unevenness in the output image in the printer disclosed in Patent Document 1 becomes significant.

  In addition, when the auxiliary platen roller disclosed in Patent Document 1 is applied to a thermal transfer printer, the thermal energy of the platen roller is transmitted to the auxiliary platen roller via both the ink sheet and the recording paper during the conveyance of the recording paper. The Therefore, the problem of uneven density in the output image becomes more prominent.

  Further, as disclosed in Patent Document 1, when the heat radiating member is a member that directly contacts the recording paper and conveys the recording paper, it is necessary to satisfy both prevention of the recording paper from being damaged and ensuring sufficient heat dissipation. There are significant restrictions in the selection of the material for the heat dissipation member. That is, a relatively soft material such as rubber or resin has a merit that it does not easily damage the surface of soft recording paper, but has a low thermal conductivity and poor heat dissipation. On the other hand, a material having a high thermal conductivity such as a metal is excellent in heat dissipation, but easily damages the recording paper.

  An object of the present invention is to stably cool a platen roller that receives heat from a thermal head during operation of a thermal transfer printer and prevent density unevenness of an output image.

The thermal transfer printer according to the present invention that achieves the above object includes the following components.
(1) The first component is a thermal head that transfers an image from a developing member to a transfer target member by heating the developing member holding the developer.
(2) The second component is a platen roller that rotates with the transfer medium sandwiched between the thermal head.
(3) The third component is a heat radiating plate that contacts the peripheral surface of the platen roller and moves according to the rotation of the platen roller.
(4) The fourth component is a heat radiating plate support portion that contacts the heat radiating plate and supports the heat radiating plate against the platen roller.

  In the thermal transfer printer according to the present invention, the heat radiating plate is supported while being pressed against the platen roller, and moves according to the rotation of the platen roller while being in contact with the peripheral surface of the platen roller. Therefore, the thermal energy of the platen roller is directly transmitted to the heat radiating plate during the conveyance of the transfer medium such as the recording paper and the operation including other states. Therefore, if the heat radiating plate is a member made of a material having a high thermal conductivity such as a metal, the platen roller is always efficiently cooled during various operations including execution of a continuous print job. As a result, density unevenness in the output image is prevented. Moreover, since the heat radiating plate moves according to the rotation of the platen roller, the surface of the platen roller is not damaged by rubbing.

1 is a schematic diagram of an image forming unit in a first state in a thermal transfer printer 1 according to a first embodiment of the present invention. 2 is a perspective view of a part of an image forming unit in the thermal transfer printer 1. FIG. 2 is a block diagram of control-related equipment in the thermal transfer printer 1. FIG. FIG. 3 is a schematic diagram of an image forming unit in a second state in the thermal transfer printer 1. FIG. 4 is a schematic diagram of an image forming unit in a third state in the thermal transfer printer 1. FIG. 6 is a schematic diagram of an image forming unit in a fourth state in the thermal transfer printer 1. It is the schematic of the image formation part of the 1st state in 1 A of thermal transfer printers which concern on 2nd Embodiment of this invention. FIG. 3 is a schematic diagram of an image forming unit in a second state in the thermal transfer printer 1A. It is the schematic of the image formation part of the 1st state in the thermal transfer printer 1B which concerns on 3rd Embodiment of this invention. FIG. 6 is a schematic diagram of an image forming unit in a second state in the thermal transfer printer 1B. It is the schematic of the image formation part in 1 C of thermal transfer printers which concern on 4th Embodiment of this invention. FIG. 10 is a schematic diagram of an image forming unit in a thermal transfer printer 1D according to a fifth embodiment of the present invention. It is the schematic of the image formation part in the thermal transfer printer 1E which concerns on 6th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiment is an example embodying the present invention, and is not an example of limiting the technical scope of the present invention.

  The thermal transfer printers 1, 1 </ b> A, 1 </ b> B, 1 </ b> C, 1 </ b> D, and 1 </ b> E according to the embodiments of the present invention are sublimation type thermal transfer printers and are surface sequential printers having a thermal head.

<First Embodiment>
First, the configuration of the image forming unit in the thermal transfer printer 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. As shown in FIGS. 1 and 2, the thermal transfer printer 1 includes a thermal head 21, a first displacement device 210, a platen roller 22, a platen roller drive motor 220, a pinch roller mechanism 24, a pinch roller drive motor 240, and an ink sheet unit. 30, a heat radiation plate 41, a main support roller 42, auxiliary support rollers 44 and 45, a pressing mechanism 43, a second displacement device 420, and a heat radiation plate detection sensor 50.

  In FIG. 2, only the thermal head 21, the platen roller 22, the ink sheet unit 30, the heat radiating plate 41, and the main support roller 42 are shown. In FIG. 2, the ink sheet unit 30 is indicated by a two-dot chain line.

  Furthermore, as shown in FIG. 3, the thermal transfer printer 1 includes a communication interface 11, a microcomputer 12, a memory controller 13, a frame memory 14, an actuator drive circuit 15, a memory 16, an image processing circuit 17, and a thermal head controller 18. . The communication interface 11, the microcomputer 12, the memory controller 13, the image processing circuit 17, and the thermal head controller 18 can exchange data with each other via, for example, a bus.

<Basic configuration of image forming unit>
The ink sheet unit 30 includes a feeding portion 31 that is a portion in which the belt-shaped ink sheet 3 is wound in a roll shape, and a winding portion 32 that is a portion in which the ink sheet 3 fed from the feeding portion 31 is wound. Prepare. Further, the ink sheet 3 includes an ink forming portion which is a portion in which a sublimable dye ink layer of a plurality of colors is formed on the surface of a base material layer made of a belt-like film, and a transparent protection on the surface of the base material layer. And a protective material forming portion which is a portion where the material layer is formed. Each of the ink forming portions and the protective material forming portion is repeatedly arranged in a predetermined order in the longitudinal direction of the strip-shaped ink sheet 3.

  The ink forming portion of the ink sheet includes, for example, a yellow ink layer portion, a magenta ink layer portion, and a cyan ink layer portion. The ink forming unit may include a black ink layer portion.

  The recording paper 4 for a sublimation thermal transfer printer has a structure in which a receiving layer is formed on the surface of a sheet-like base material layer. The receiving layer is a resin layer having high affinity with the dye ink, and the ink of the ink sheet 3 is transferred to the receiving layer of the recording paper 4.

  The pinch roller mechanism 24 is a mechanism for transporting the recording paper 4 in the first direction and the second direction opposite thereto, and includes a pinch roller 241 and a grip roller 242 that rotate while sandwiching the recording paper 4. The pinch roller drive motor 240 is a motor that rotates the pinch roller 241 forward and backward.

  The platen roller 22 is a roller that rotates while sandwiching the recording sheet 4 as a transfer target and the ink sheet 3 as a developer between the thermal head 21. The platen roller drive motor 220 is a motor that rotates the platen roller 22 forward and backward.

  The thermal head 21 is a device that sequentially heats each ink forming portion and the protective material forming portion in the ink sheet 3. A heater 211 is provided at a contact portion of the thermal head 21 with the ink sheet 3. The thermal head 21 can adjust the heating energy of the ink sheet 3 in pixel units of the image.

  The first displacement device 210 is an actuator that supports the thermal head 21 so as to be movable. The thermal head 21 can be moved between the recording position where the ink sheet 3 is sandwiched between the thermal head 21 and the platen roller 22 by the first displacement device 210 and the retracted position away from the platen roller 22. It is supported. The first displacement device 210 is, for example, a solenoid.

  FIG. 1 shows a state where the thermal head 21 is present at the recording position, and FIG. 5 described later shows a state where the thermal head 21 is present at the retracted position.

  In a state where the thermal head 21 exists at the recording position, the recording paper 4 is conveyed in the first direction by the pinch roller mechanism 24 and the platen roller 22 that rotate in the first direction. At that time, the ink sheet 3 moves from the feeding unit 31 to the winding unit 32 in a state of being in close contact with the recording paper 4. Further, the thermal head 21 heats the moving ink sheet 3 to transfer the image or the overcoat layer from the ink sheet 3 to the recording paper 4. At that time, the thermal head 21 heats the ink forming portion of the ink sheet 3 with heating energy corresponding to the density of each pixel in the image data.

  On the other hand, the recording paper 4 is conveyed between the platen roller 22 and the ink sheet 3 by the pinch roller mechanism 24 that rotates in the second direction in a state where the thermal head 21 exists at the retracted position. At that time, the ink sheet 3 is stopped in a state of being separated from the recording paper 4 as shown in FIG.

  The thermal transfer printer 1 moves the thermal head 21 to the recording position, heats the ink sheet 3 and transports the recording paper 4 in the first direction, and moves the thermal head 21 to the retracted position. Then, the operation of returning the position of the recording paper 4 in the second direction by one page is sequentially repeated. Such an operation is controlled by the microcomputer 12.

  By the operation of the thermal transfer printer 1 described above, the ink images of the respective colors are sequentially transferred from the ink sheet 3 to the recording paper 4. Further, the overcoat layer is transferred from the ink sheet 3 to the recording paper 4 so as to cover the color image on the recording paper 4.

  The overcoat layer is a protective layer that improves the light resistance and fingerprint resistance of the image formed on the recording paper 4, and also plays a role of improving the smoothness of the surface of the recording paper 4 and improving the glossiness.

<Basic configuration of control-related equipment>
The communication interface 11 is a device that relays data communication between the microcomputer 12 and the external host device 5.

  The microcomputer 12 is a processor that performs data communication with the host device 5 through the communication interface 11 and controls the image processing circuit 17, the thermal head controller 18, and the actuator drive circuit 15.

  The frame memory 14 is a high-speed memory that temporarily stores image data, that is, gradation data of each pixel of the image.

  The memory controller 13 is a device that relays data transfer between the frame memory 14 and other devices connected by a bus at high speed. The microcomputer 12, the image processing circuit 17, and the thermal head controller 18 read and write image data to and from the frame memory 14 through the memory controller 13.

  The memory 16 is a non-volatile memory that stores a control program executed by the microcomputer 12 and various parameters referred to by the microcomputer 12.

  The image processing circuit 17 is a circuit that executes calculations for performing various image correction processes such as sharpness calculation and gamma conversion on the image data when a process start command is received from the microcomputer 12.

  The thermal head controller 18 is a circuit that adjusts the heating energy of the thermal head 21 for each pixel based on the image data corrected by the image processing circuit 17.

  The actuator drive circuit 15 sends a drive signal and a stop signal to the actuator including the first displacement device 210, the platen roller drive motor 220, the pinch roller drive motor 240, and the second displacement device 420 in accordance with a control command from the microcomputer 12. It is a circuit to output. The microcomputer 12 controls the operations of the first displacement device 210, the platen roller drive motor 220, the pinch roller drive motor 240, and the second displacement device 420 through the actuator drive circuit 15.

<Configuration specific to thermal transfer printer 1>
The heat radiating plate 41, the main support roller 42, the auxiliary support rollers 44 and 45, the pressing mechanism 43, the second displacement device 420, and the heat radiating plate detection sensor 50 are components unique to the thermal transfer printer 1 that is not included in the conventional thermal transfer printer. .

  The heat radiating plate 41 is a plate-like member that contacts the peripheral surface of the platen roller 22 and moves according to the rotation of the platen roller 22. The heat sink 41 is a member having high thermal conductivity, and is a metal member such as aluminum, for example. The heat sink 41 in this embodiment is a flat member.

  The main support roller 42 is a driven roller that abuts on the heat radiating plate 41 and rotates according to the movement of the heat radiating plate 41 while pressing and supporting the heat radiating plate 41 against the platen roller 22. In order to prevent the main support roller 42 from slipping and spinning with respect to the surface of the heat radiating plate 41, at least the surface layer portion of the main support roller 42 is made of a material having a high frictional resistance such as urethane resin or rubber. It is desirable.

  The pressing mechanism 43 is a mechanism that elastically biases the main support roller 42 against the heat radiating plate 41. The pressing mechanism 43 is, for example, a spring mechanism. The main support roller 42 is an example of a heat dissipation plate support that supports the heat dissipation plate 41.

  The second displacement device 420 includes an operating position for holding the heat sink 41 at a position where the main support roller 42 is pressed against the platen roller 22, and a retreat position for holding the heat sink 41 at a position spaced apart from the platen roller 22. It is an actuator that is displaced between. The second displacement device 420 is, for example, a solenoid.

  The auxiliary support rollers 44 and 45 are rotating bodies that support the heat radiating plate 41 together with the main support roller 42. In the present embodiment, the auxiliary support rollers 44 and 45 support the heat radiating plate 41 together with the main support roller 42 only when the main support roller 42 is in the retracted position. The auxiliary support rollers 44 and 45 are not necessarily rotary bodies, and may be rod-shaped members, for example.

  The heat radiating plate detection sensor 50 is a sensor that detects the arrival of the heat radiating plate 41 at positions at both ends in the moving range of the heat radiating plate 41. Hereinafter, one of the two heat sink detection sensors 50 is referred to as a first heat sink detection sensor 51 and the other is referred to as a second heat sink detection sensor 52.

  The heat sink detection sensor 50 is, for example, a non-contact sensor disposed in the vicinity of both end positions in the moving range of the heat sink 41, or a micro switch in which contact ends are disposed at both end positions in the moving range of the heat sink 41. It is. The non-contact sensor is, for example, an inductive proximity switch, a capacitive proximity switch, an ultrasonic proximity switch, or a photoelectric proximity switch.

  The microcomputer 12 controls the second displacement device 420 according to the detection result of the heat sink detection sensor 50 and the rotation direction of the platen roller 22.

<Image transfer processing>
After the correction processing by the image processing circuit 17 is executed on the image data received from the host device 5, the microcomputer 12 executes the image transfer processing. Then, in the image transfer process, the microcomputer 12 changes the control state of the image forming unit to the first control state shown in FIG. 1, the second control state shown in FIG. 4, the third control state shown in FIG. Switching to the four states of the fourth control state shown in FIG.

  As shown in FIG. 1, in the first control state, the microcomputer 12 controls the first displacement device 210 and the second displacement device 420 to hold the thermal head 21 at the recording position, and the main support roller 42. Is held in the operating position. Further, the microcomputer 12 rotates the platen roller 22 and the pinch roller 241 in the first rotation direction. 1, 4, 5, and 6, the first rotation direction is a clockwise direction.

<First control state>
In the first control state, the recording paper 4 is conveyed in the first movement direction, and each ink forming portion and the protective material forming portion of the ink sheet 3 pass through the position of the thermal head 21 in a state of overlapping the recording paper 4. . Further, the heat radiating plate 41 is supported by the main support roller 42 while being pressed against the platen roller 22. At this time, the heat radiating plate 41 moves in the second moving direction opposite to the first moving direction as the platen roller 22 rotates. In FIGS. 1, 4, 5, and 6, the first movement direction is the right direction, and the second movement direction is the left direction.

  Further, in the first control state, when the first heat radiation plate detection sensor 51 detects that the heat radiation plate 41 has reached one end of the movement range, the microcomputer 12 changes the control state to the first control state (FIG. Switch from 1) to the second control state (FIG. 4).

<Second control state>
As shown in FIG. 4, in the second control state, the microcomputer 12 controls the first displacement device 210 and the second displacement device 420 to hold the thermal head 21 at the recording position, and the main support roller 42. Is moved to the retracted position. Further, the microcomputer 12 keeps the platen roller 22 and the pinch roller 241 rotated in the first rotation direction.

  In the second control state, the recording paper 4 is continuously conveyed in the first movement direction from the first control state, and each ink forming portion and the protective material forming portion in the ink sheet 3 are in a state where they overlap with the recording paper 4. Passes through the position of the head 21. On the other hand, the heat radiating plate 41 is supported by the main support roller 42 and the auxiliary support roller 44 in a state of being stopped at a position away from the platen roller 22.

  Further, in the second control state, the microcomputer 12 changes the control state from the second control state (FIG. 4) to the third state when the process of transferring the image of one color ink or the overcoat layer to the recording paper 4 is completed. Switch to the control state (FIG. 5).

<Third control state>
As shown in FIG. 5, in the third control state, the microcomputer 12 controls the first displacement device 210 and the second displacement device 420 to hold the thermal head 21 in the retracted position, and the main support roller 42. Is moved to the operating position. Further, the microcomputer 12 rotates the platen roller 22 and the pinch roller 241 in the second rotation direction opposite to the first rotation direction.

  In the third control state, the recording paper 4 is conveyed in the second movement direction, and the ink sheet 3 is held in a state of being stopped away from the recording paper 4. Further, the heat radiating plate 41 is supported by the main support roller 42 while being pressed against the platen roller 22. At this time, the heat radiating plate 41 moves in the first moving direction according to the rotation of the platen roller 22.

  Further, in the third control state, when the second heat radiating plate detection sensor 52 detects that the heat radiating plate 41 has reached the other end of the moving range, the microcomputer 12 changes the control state to the third control state (FIG. Switching from 5) to the fourth control state (FIG. 6).

<4th control state>
As shown in FIG. 6, in the fourth control state, the microcomputer 12 controls the first displacement device 210 and the second displacement device 420 to hold the thermal head 21 at the recording position, and the main support roller 42. Is moved to the retracted position. Further, the microcomputer 12 keeps the platen roller 22 and the pinch roller 241 rotated in the second rotation direction.

  In the fourth control state, the recording paper 4 is continuously conveyed in the second movement direction from the third control state, and the ink sheet 3 is held in a state of being stopped away from the recording paper 4 and continuing from the third control state. Is done. On the other hand, the heat radiating plate 41 is supported by the main support roller 42 and the auxiliary support roller 45 while being stopped at a position away from the platen roller 22.

  Further, in the fourth control state, the microcomputer 12 changes the control state from the fourth control state (FIG. 6) when the recording paper 4 is conveyed by an amount corresponding to the length of the image forming range of one page. Switch to the first control state (FIG. 1). Further, the microcomputer 12 switches the color of the image to be transferred to the recording paper 4 or switches from the transfer of the image to the transfer of the overcoat layer. However, the microcomputer 12 performs control to discharge the recording paper 4 from the image forming unit when the transfer of the overcoat layer is completed in the fourth control state.

  As described above, the microcomputer 12 controls the position of the main support roller 42 by controlling the second displacement device 420 according to the detection result of the heat radiating plate detection sensor 50 and the rotation direction of the platen roller 22. Displace to the operating position and the retracted position. Note that controlling the second displacement device 420 according to the rotation direction of the platen roller 22 is synonymous with controlling the second displacement device 420 according to the moving direction of the heat sink 41.

<Effect>
In the thermal transfer printer 1, the heat radiating plate 41 is supported while being pressed against the platen roller 22, and moves according to the rotation of the platen roller 22 while contacting the peripheral surface of the platen roller 22. Accordingly, the heat energy of the platen roller 22 is directly transmitted to the heat radiating plate 41 during the conveyance of the recording paper 4 and the operation including other states. Therefore, if the heat radiating plate 41 is a member made of a material having high thermal conductivity such as metal, the platen roller 22 is always efficiently cooled during various operations including execution of a continuous print job. . As a result, density unevenness in the output image is prevented. Moreover, since the heat radiating plate 41 moves according to the rotation of the platen roller 22, the surface of the platen roller 22 is not damaged by rubbing.

  In the thermal transfer printer 1, a main support roller 42 that is a driven roller that rotates in accordance with the movement of the heat radiating plate 41 is employed as a member that supports the heat radiating plate 41. Therefore, for the purpose of smooth movement of the heat radiating plate 41, it is not necessary to supply a lubricant such as grease between the heat radiating plate 41 and a member supporting the heat radiating plate 41, and the structure is simplified.

  In the thermal transfer printer 1, the microcomputer 12 controls the second displacement device 420 according to the detection result of the heat radiating plate detection sensor 50 and the rotation direction of the platen roller 22, whereby the main support roller 42 operates. Displace between position and retracted position. Therefore, the heat radiating plate 41 shorter than the recording paper 4 can be employed, and the heat radiating mechanism can be made compact.

Second Embodiment
Next, a thermal transfer printer 1A according to a second embodiment of the present invention will be described with reference to schematic diagrams shown in FIGS. The thermal transfer printer 1A has a configuration in which only some components are different from those of the thermal transfer printer 1 shown in FIGS. 7 and 8, the same components as those shown in FIGS. 1 to 6 are denoted by the same reference numerals. Hereinafter, only the differences of the thermal transfer printer 1A from the thermal transfer printer 1 will be described.

  The thermal transfer printer 1 </ b> A is different from the thermal transfer printer 1 in that it includes a direction changing mechanism that changes the traveling direction of the moving heat sink 41 in accordance with the rotation of the platen roller 22 in one direction. That is, the thermal transfer printer 1A has a mechanism for changing the traveling direction of the heat radiating plate 41 moving in the first direction or the second direction in the first control state and the third control state shown in FIGS. I have. Hereinafter, an example of the direction change mechanism of the heat sink 41 will be described. FIG. 7 shows the image forming unit in the first control state corresponding to the control state shown in FIG.

  7 and 8, the thermal transfer printer 1A includes a second displacement device 420A that displaces the main support roller 42, and two third displacement devices 440 and 450 that displace the two auxiliary support rollers 44, respectively. It has. The microcomputer 12 controls the second displacement device 420A and the third displacement devices 440 and 450 through the actuator drive circuit 15.

  In the thermal transfer printer 1 </ b> A, the heat radiating plate 41 is always supported by the main support roller 42 and one of the two auxiliary support rollers 44 and 45.

  The third displacement devices 440 and 450 are devices that displace the height at which the auxiliary support rollers 44 and 45 support the heat radiating plate 41 to an arbitrary height within a predetermined range. Similarly, the second displacement device 420A is a device that displaces the height at which the main support roller 42 supports the heat radiating plate 41 to an arbitrary height within a predetermined range. The second displacement device 420A and the third displacement devices 440 and 450 are, for example, a device in which a servo motor and a link mechanism are combined, or an electric cylinder.

  The microcomputer 12 executes control to displace the auxiliary support rollers 44 and 45 through the third displacement devices 440 and 450. Similarly, the microcomputer 12 performs control to displace the main support roller 42 through the second displacement device 420A.

  When the first heat sink detection sensor 51 detects that the microcomputer 12 has reached one end of the horizontal movement range of the heat sink 41 in the first control state shown in FIG. The support roller 44 and the main support roller 42 are displaced. At that time, the microcomputer 12 gradually displaces the position of one auxiliary support roller 44 downward. Thereby, as shown in FIG. 8, the heat radiating plate 41 shifts from a horizontally held state to an inclinedly held state.

  When the heat radiating plate 41 is inclined, the distance between the main support roller 42 and the platen roller 22 required to maintain the state where the heat radiating plate 41 is sandwiched between the main support roller 42 and the platen roller 22 changes. Therefore, in parallel with the displacement of the auxiliary support roller 44, the microcomputer 12 maintains the state in which the heat radiating plate 41 is sandwiched between the main support roller 42 and the platen roller 22. The main support roller 42 is displaced downward at a speed slower than the displacement speed. In addition, since the inclination speed of the heat sink 41 is known, the microcomputer 12 displaces the main support roller 42 downward at a predetermined speed.

  When the microcomputer 12 performs the control described above, the traveling direction of the heat radiating plate 41 that is moving according to the rotation of the platen roller 22 in the first rotation direction is shown in FIG. 8 from the horizontal direction shown in FIG. Turn diagonally downward. That is, in the thermal transfer printer 1A, the flat heat sink 41 moves two-dimensionally.

  Although illustration is saved, the microcomputer 12 performs the same control in the third control state corresponding to the control state shown in FIG.

  That is, in the third control state corresponding to the state shown in FIG. 5, the microcomputer 12 detects that the other end of the horizontal movement range of the heat sink 41 has been detected by the second heat sink detection sensor 52. In this case, the other auxiliary support roller 45 and the main support roller 42 are displaced. At that time, the microcomputer 12 gradually displaces the position of the other auxiliary support roller 45 and displaces the main support roller 42 downward at a speed slower than the displacement speed of the auxiliary support roller 44. Thereby, the heat sink 41 shifts from a state of being held horizontally to a state of being held obliquely.

  1 A of thermal transfer printers can move the heat sink 41 two-dimensionally by providing the direction change mechanism of the heat sink 41. In this case, compared with the case where the heat sink 41 moves only in the one-dimensional direction, the width of the space to be secured for the movement of the heat sink 41 can be reduced. As a result, the installation area of the apparatus can be reduced.

<Third Embodiment>
Next, a thermal transfer printer 1B according to a third embodiment of the present invention will be described with reference to schematic diagrams shown in FIGS. The thermal transfer printer 1B has a configuration in which only some components are different from those of the thermal transfer printer 1 shown in FIGS. 9 and 10, the same components as those shown in FIGS. 1 to 6 are given the same reference numerals. Hereinafter, only different points of the thermal transfer printer 1B from the thermal transfer printer 1 will be described.

  The thermal transfer printer 1B is different from the thermal transfer printer 1 in that it includes a direction changing mechanism that changes the traveling direction of the moving heat radiation plate 41 in accordance with the rotation of the platen roller 22 in one direction. However, the direction changing mechanism of the thermal transfer printer 1B is different from the direction changing mechanism of the thermal transfer printer 1A.

  The direction changing mechanism of the thermal transfer printer 1B includes guide pins 441 and 442 formed on the side surface of the heat radiating plate 41 and guide rails 44B and 45B for guiding the traveling directions of the guide pins 441 and 442 along a curved path. And. Furthermore, the thermal transfer printer 1B includes a second displacement device 420A that displaces the height at which the main support roller 42 supports the heat radiating plate 41 to an arbitrary height within a predetermined range, similarly to the thermal transfer printer 1A. ing. The microcomputer 12 executes control to displace the main support roller 42 through the second displacement device 420A.

  In the thermal transfer printer 1B, the traveling direction of the moving heat sink 41 is changed from the horizontal direction shown in FIG. 9 to the obliquely downward direction shown in FIG. 10 according to the rotation of the platen roller 22 in the first rotation direction. That is, in the thermal transfer printer 1B, the flat heat sink 41 moves two-dimensionally.

  Further, when the heat radiating plate 41 is inclined, the distance between the main support roller 42 and the platen roller 22 required to maintain the state where the heat radiating plate 41 is sandwiched between the main support roller 42 and the platen roller 22 changes. Therefore, the microcomputer 12 moves the main support roller 42 downward at a speed corresponding to the inclination speed of the heat sink 41 so that the heat sink 41 is sandwiched between the main support roller 42 and the platen roller 22. Displace to In addition, since the inclination speed of the heat sink 41 is known, the microcomputer 12 displaces the main support roller 42 downward at a predetermined speed.

  Further, in the thermal transfer printer 1B, a heat radiating plate detection sensor 50B that detects the arrival of the heat radiating plate 41 at each of the both ends of the curvilinear movement range of the heat radiating plate 41 is provided. A first heat radiating plate detection sensor 51B is disposed at one end in the curved movement range of the heat radiating plate 41, and a second heat radiating plate detection sensor 52B is disposed at the other end. 9 and 10 is a contact type micro switch or the like.

  The thermal transfer printer 1 </ b> B can move the heat radiating plate 41 two-dimensionally by including the direction changing mechanism of the heat radiating plate 41. In this case, compared with the case where the heat sink 41 moves only in the one-dimensional direction, the width of the space to be secured for the movement of the heat sink 41 can be reduced. As a result, the installation area of the apparatus can be reduced.

<Fourth embodiment>
Next, a thermal transfer printer 1C according to a fourth embodiment of the present invention will be described with reference to the schematic diagram shown in FIG. The thermal transfer printer 1C has a configuration in which only the shape of the heat radiating plate is different from that of the thermal transfer printer 1 shown in FIGS. 11, the same components as those shown in FIGS. 1 to 6 are given the same reference numerals. Hereinafter, only different points of the thermal transfer printer 1C from the thermal transfer printer 1 will be described.

  As shown in FIG. 11, the heat radiating plate 41C provided in the thermal transfer printer 1C is a curved plate-like member. Therefore, when the heat radiating plate 41C is moved between the main support roller 42 and the platen roller 22 according to the rotation of the platen roller, the heat radiating plate 41C moves two-dimensionally even without a direction changing mechanism.

  In the thermal transfer printer 1 </ b> C, the heat sink detection sensor 50 detects the arrival of the heat sink 41 </ b> C at both ends in the curved movement range of the heat sink 41. Also in the thermal transfer printer 1 </ b> C, the microcomputer 12 switches the four control states as in the case of the thermal transfer printer 1.

  The thermal transfer printer 1 </ b> C includes the curved plate-like heat sink 41 </ b> C, so that the heat sink 41 can be moved two-dimensionally without providing a special mechanism. In this case, compared with the case where the heat sink 41 moves only linearly, the width of the space to be secured for the movement of the heat sink 41C can be reduced. As a result, the installation area of the apparatus can be reduced.

<Fifth Embodiment>
Next, a thermal transfer printer 1D according to a fifth embodiment of the invention will be described with reference to the schematic diagram shown in FIG. Compared with the thermal transfer printer 1 shown in FIGS. 1 to 6, the thermal transfer printer 1 </ b> D has a configuration in which only a member that supports the heat radiating plate 41 is different. In FIG. 12, the same components as those shown in FIGS. 1 to 6 are given the same reference numerals. Hereinafter, only different points of the thermal transfer printer 1D from the thermal transfer printer 1 will be described.

  As shown in FIG. 12, the thermal transfer printer 1D has a configuration in which the main support roller 42 in the thermal transfer printer 1 is replaced with a main support member 42D. The main support member 42 </ b> D is a member that abuts on the heat radiating plate 41 and supports the heat radiating plate 41 against the platen roller 22. However, the main support member 42 </ b> D supports the heat radiating plate 41 while being rubbed against the surface of the heat radiating plate 41 according to the movement of the heat radiating plate 41.

  Also in the thermal transfer printer 1D, the platen roller 22 is always efficiently cooled during various operations including execution of a continuous print job, and density unevenness of the output image is prevented. However, in the thermal transfer printer 1D, it is desirable to supply a lubricant such as grease between the heat radiating plate 41 and the main support member 42D that supports the heat radiating plate 41 for the purpose of smooth movement of the heat radiating plate 41.

<Sixth Embodiment>
Next, a thermal transfer printer 1E according to a sixth embodiment of the present invention will be described with reference to the schematic diagram shown in FIG. The thermal transfer printer 1E has a configuration in which a cooling fan 60 is added as compared with the thermal transfer printer 1 shown in FIGS. In FIG. 13, the same components as those shown in FIGS. 1 to 6 are given the same reference numerals. Hereinafter, only different points of the thermal transfer printer 1E from the thermal transfer printer 1 will be described.

  The thermal transfer printer 1 </ b> E includes a cooling fan 60 that forcibly cools the heat radiation plate 41. Thereby, cooling of the heat sink 41 is cooled more efficiently, and density unevenness of the output image is more reliably prevented.

<Others>
The cooling fan 60 of the thermal transfer printer 1E may be applied to the thermal transfer printers 1, 1A, 1B, 1C, and 1D shown as other embodiments. It is also conceivable that the curved plate-shaped heat radiation plate 41C is applied to the thermal transfer printers 1A, 1B, and 1D shown as other embodiments.

  Further, in the thermal transfer printers 1, 1 </ b> C, 1 </ b> D, and 1 </ b> E, when the heat radiation plates 41 and 41 </ b> C that are longer than the moving distance of the heat radiation plate 41 due to the platen roller 22 continuously rotating in the same direction are employed It is also conceivable that the two-displacement device 420 and the heat sink detection sensor 50 are omitted.

  1, 1A, 1B, 1C, 1D, 1E Thermal transfer printer, 3 ink sheet, 4 recording paper, 5 host device, 11 communication interface, 12 microcomputer, 13 memory controller, 14 frame memory, 15 actuator drive circuit, 16 memory, 17 Image processing circuit, 18 Thermal head controller, 21 Thermal head, 22 Platen roller, 24 Pinch roller mechanism, 30 Ink sheet unit, 41, 41C Heat radiation plate, 42 Main support roller, 42D Main support member, 43 Pressing mechanism, 44, 45 auxiliary support roller, 44B, 45B guide rail, 50, 50B heat sink detection sensor, 60 cooling fan, 210 first displacement device, 211 heater, 220 platen roller drive motor, 240 pinch roller drive motor Data, 420,420A second displacement device, 440, 450 third displacement device, 441, 442 guide pin.

Claims (6)

A thermal head that transfers an image from the developer to the transfer target by heating the developer holding the developer;
A thermal transfer printer comprising: a platen roller that rotates with the transfer medium sandwiched between the thermal head;
A heat sink that contacts the peripheral surface of the platen roller and moves according to the rotation of the platen roller;
A heat transfer printer comprising: a heat radiating plate support portion that abuts the heat radiating plate and supports the heat radiating plate against the platen roller.   The thermal transfer printer according to claim 1, wherein the heat radiating plate support is a driven roller that rotates according to the movement of the heat radiating plate. A sensor for detecting the arrival of the heat sink to each of the positions at both ends in the movement range of the heat sink;
Between the first position for holding the heat sink at a position pressed against the platen roller and the second position for holding the heat sink at a position spaced apart from the platen roller. A displacement device for displacing;
The thermal transfer printer according to claim 1, further comprising a control unit that controls the displacement device according to a detection result of the sensor and a rotation direction of the platen roller.   4. The thermal transfer printer according to claim 1, further comprising a direction changing mechanism that changes a traveling direction of the moving heat sink in accordance with rotation of the platen roller in one direction. 5.   The thermal transfer printer according to claim 1, wherein the heat radiating plate is a curved plate-like member.   The thermal transfer printer according to claim 1, further comprising a cooling unit that forcibly cools the heat radiating plate.

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