JP2010115862A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer that has increased printing speed by uniformizing the ability of a cooling device of a liquid cooling system to cool a plurality of thermal heads when cooling the thermal heads by use of the cooling device. <P>SOLUTION: The printer conveys recording media placed in a housing, in a predetermined direction along the plurality of thermal heads successively and prints on them. In the printer, the cooling device for cooling the plurality of thermal heads includes: a plurality of heat receiving jackets which are thermally connected to the corresponding thermal heads, receive heat from them, and are disposed in serial relative to one another to form a circulation passage for a coolant; a heat dissipating section comprising a fan and radiator; a pump for driving the coolant in a circulative manner; and a means maintaining the recording medium placed in the housing, at a low temperature. The plurality of thermal heads and the heat receiving jackets thereof are disposed so that order in which the thermal heads record on each conveyed medium is reverse to order in which the cooling liquid circulates into the jackets. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing machine that performs printing with a plurality of thermal heads, and more particularly, to a printing machine that achieves higher printing speed by cooling a thermal head with a liquid cooling type cooling device.

  Typical devices that perform printing using heat generation include an ink ribbon and a thermal recording paper. Particularly, in the case of a printing apparatus using an ink ribbon capable of color printing, a plurality of thermal heads are provided because a plurality of colors are used. On the other hand, in a printing apparatus using an ink ribbon, color printing is usually performed by using a plurality of ribbons to which inks of three or more colors are applied.

  Such a thermal head is disposed so as to face the recording paper with the ink ribbon interposed therebetween, and printing is performed by transferring the ink on the ink ribbon onto the recording paper by the heat of the thermal head. The thermal heads are arranged at predetermined intervals along the recording paper conveyance path. For example, in the case of a printing apparatus having three thermal heads, these three thermal heads are respectively a yellow thermal head, a magenta thermal head, and a cyan thermal head along the recording paper conveyance path. At predetermined intervals, the recording paper is arranged in order from the upstream side in the conveyance direction. Therefore, printing on the recording paper is performed by first printing a yellow color image by the thermal head for yellow as described above while conveying the recording paper, and then printing sequentially in magenta and cyan. To print a full color image.

  On the other hand, in a printing apparatus using a color thermosensitive recording paper, a full color image is printed using a color thermosensitive recording paper having at least three thermosensitive coloring layers that develop color when heated. This color thermosensitive recording paper is provided with, for example, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer, respectively. The thermal sensitivity of will be different. Each thermosensitive coloring layer is provided in a laminated manner. Generally, since the cyan thermosensitive coloring layer has the lowest thermal sensitivity, it is provided in the lowermost layer. Sensitivity is high, so it is provided on the top layer. On the other hand, when recording a thermosensitive coloring layer with high thermal sensitivity in the upper layer, the recorded thermosensitive coloring layer is irradiated with a specific electromagnetic ray so that the recorded thermosensitive coloring layer in the lower layer does not recolor. A method of photofixing the recorded color is used.

  In a printing apparatus using such color thermal recording paper, for example, when the number of thermal heads is 3, from the upstream side in the recording paper conveyance direction at a predetermined interval along the thermal recording paper conveyance path. , A thermal head for yellow, a thermal head for magenta, and a thermal head for cyan are arranged. For printing, while transporting the color thermal recording paper, first, a yellow thermal head is used to print a yellow color image on the uppermost yellow thermal coloring layer, and after the yellow color image is printed, the yellow ultraviolet lamp is used for ultraviolet rays. To fix the yellow thermosensitive coloring layer. Similarly, magenta and cyan are sequentially printed and light-fixed to print a full color image.

  However, in the case of a printing apparatus that performs printing using heat as described above, since a thermal head is used as a heating element, the heat generated by the thermal head is stored in the head particularly when performing continuous printing. Therefore, the temperature will rise. This increase in temperature may cause malfunction such as reactive color development or transfer of ink even when the thermal head is not energized, and there is a concern that print quality may be significantly reduced.

  For this reason, in a printing apparatus that performs printing using heat, it is important to cool the thermal head in order to increase the printing speed. On the other hand, conventionally, as a method for cooling a thermal head, a forced air cooling method in which a thermal head is cooled by attaching a fan and a heat sink is generally used. However, in the limited space around the thermal head, there is a limit to the improvement of the cooling capacity by the forced air cooling method. Instead, a cooling device by the liquid cooling method has been studied. In this liquid cooling type cooling device, the heat of the thermal head is moved to a wide space and can be cooled by a large radiator there, so that a significant improvement in cooling performance can be realized.

Techniques for cooling a thermal head by such a liquid example method are disclosed in Patent Documents 1 to 3 below.
JP-A-6-31957 JP 2006-218701 A JP 2006-327143 A

  However, a printing apparatus equipped with a thermal head equipped with a liquid cooling type cooling device as described above has the technical problem to be solved as described below.

  First, in the thermal print head described in Patent Document 1, the heat of the thermal print head is transferred to a support member having a cavity through which a coolant flows and a heat transfer surface, thereby generating heat of the thermal print head. It is configured to cool. However, in the technique described in Patent Document 1, there is no description regarding a cooling method between a plurality of thermal heads, thermal effects, and the like.

  In the thermal printer cooling device described in Patent Document 2, cooling pipes of adjacent recording units are connected in series with each other, and cooling water is sequentially supplied from the uppermost recording unit to the lower recording units. . However, in the technique described in Patent Document 2, since the cooling water received and heated on the upstream side is passed to the downstream side, the heat conversion performance of the cooling water in the recording unit located on the downstream side is gradually increased. Has the problem of lowering.

  Further, in the printer described in Patent Document 3, a plurality of recording units are arranged along a recording medium conveyance path, and a heat sink having a cooling liquid passage is provided between the cooling liquid passages. Connected in parallel to form a cooling device. According to this, when printing is performed by each recording unit, the line thermal head is cooled so as not to store heat above a predetermined temperature. However, in the technique described in Patent Document 3, there is still a concern in increasing the size and complexity of the apparatus, such as requiring a plurality of pipes for discharging cooling water from each heat sink and transferring it to the manifold. .

  Accordingly, the present invention has been made in view of the above-described problems in the prior art, and provides a printing machine capable of achieving a higher printing speed by leveling the cooling capacity between a plurality of thermal heads. That is the purpose.

  In order to achieve the above object, according to the present invention, first, a means for transporting a recording medium placed inside a housing in a predetermined direction, and a transport direction of the recording medium transported by the means are arranged. A plurality of thermal heads arranged in the housing, and a cooling device for cooling the plurality of thermal heads, and sequentially transporting the recording medium along the plurality of thermal head units. In the printing machine that performs printing, the cooling device is thermally connected to each of the plurality of thermal heads to receive the heat of the thermal heads, and is arranged serially with each other to circulate the refrigerant liquid. A plurality of heat receiving members forming a path; at least a fan; and disposed in the vicinity of the housing, for radiating heat from the plurality of heat receiving members via a radiator; and A pump that circulates the liquid, and a piping member that is arranged to circulate the refrigerant liquid between the plurality of heat receiving members, the heat radiating unit, and the pump, and further, Means for holding the recording medium placed on the recording medium at a low temperature, the order of recording by the plurality of thermal heads on the transported recording medium, and the order in which the refrigerant liquid circulates to the plurality of heat receiving members; A printing press that is arranged so that it is reversed.

  According to the present invention, in the printing press described above, the means for holding the recording medium constituting the cooling device at a low temperature includes the fan of the heat radiating unit disposed in the vicinity of the casing. And the recording medium placed inside the casing are preferably arranged at positions facing both of them, and the cooling device further includes the plurality of heat receiving members. It is preferable that the gap is connected using a polymer tube having flexibility, and a gas-liquid separation means is provided in the circulation path of the refrigerant liquid.

  Further, in the present invention, in the printing press described above, each of the plurality of heat receiving members constituting the cooling device includes a plate-like member thermally bonded to the thermal head and a U-shaped pipe. Preferably, the gas-liquid separation means uses a tank that stores the refrigerant liquid therein, and the tank is part of the circulation flow path and is located upstream of the pump. It is preferable to provide it. Further, the number of the plurality of thermal heads is three, and the number of the plurality of heat receiving members that receive the heat of the thermal head is also three.

  According to the above-described printing machine according to the present invention, a plurality of heat receiving members (jackets) that are attached in thermal connection to a plurality of thermal heads are serially connected to simplify piping, and the temperature is lowered in the housing. Considering the temperature change associated with the printing of the recording medium that is kept and transported sequentially, in the printing order of each thermal head, the lower temperature side of the recording medium is the downstream side through which the refrigerant liquid flows, That is, by reversing the order of recording by the plurality of thermal heads and the order in which the refrigerant liquid circulates to the plurality of heat receiving members, the cooling capacity by the plurality of heat receiving members (jackets) is leveled, thereby enabling printing. It achieves a practically excellent effect of achieving high speed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that FIG. 1 attached is a diagram showing a schematic configuration of the printing press according to the present invention, and FIG. 2 is a partially enlarged view showing a jacket peripheral portion constituting the cooling device in the printing press according to the present invention. It is a perspective view.

  First, as shown in FIG. 1, a recording medium (rolled recording paper) 2 formed in a roll form is placed inside the casing of the printing press 1. As shown in the figure, the recording paper 2 is sandwiched between a pair of pinch rollers 3 and is conveyed in the direction of the white arrow by the rotation of the pinch rollers 3. The conveyance speed of the recording paper 2 is appropriately set by controlling the rotation speed of the pinch roller 3 by the control circuit 4. The recording paper 2 conveyed by these pinch rollers 3 is printed by a plurality of thermal heads arranged in the order of thermal head C, thermal head B, and thermal head A in the conveyance direction. Each of the thermal heads A, B, and C includes a plurality of heating elements 20 arranged in the width direction of the recording paper 2, and each heating element 20 is based on print data input to the printing machine. Driven by heating.

  Here, heat receiving jackets 5A, 5B, and 5C for cooling are thermally bonded to the thermal heads A, B, and C, respectively. Further, ink ribbons 6A, 6B, 6C for transferring ink to the recording paper 2 are provided in a state of being wound in a roll shape so as to face the thermal heads A, B, C. The ink ribbons 6A, 6B, and 6C of each thermal head are divided into, for example, yellow, magenta, and cyan. Each of the ink ribbons 6A, 6B, and 6C is used by the take-up roll 7 so that the unused portion is disposed at a position facing the thermal heads A, B, and C at the time of printing. Is wound in a direction opposite to the conveying direction. The platen roller 8 moves to the thermal heads A, B, and C during printing, that is, the thermal heads A, B, and C, the ink ribbons 6A, 6B, and 6C, and the recording paper 2 are in close contact with each other. Thus, the ink of the ink ribbons 6A, 6B, 6C melted by the heat of the thermal heads A, B, C is reliably transferred to the recording paper 2.

  Subsequently, the recording paper 2 printed by each of the thermal heads A, B, and C is further conveyed to the position of the cutter 9, where it is cut to a desired length by the action of the cutter 9, and then cut. The recording sheet 2 is discharged onto the tray 10.

  Here, the configuration and operation of the cooling device for the thermal heads A, B, and C will be described below. The cooling device 100 is a liquid cooling type cooling device that circulates and drives a refrigerant liquid, and includes heat receiving jackets 5A, 5B, and 5C for receiving heat from the thermal heads A, B, and C, and a radiator 11 for radiating heat. A fan 12 for applying cooling air (air) to the radiator 11, a pump 13 for circulating the refrigerant liquid, and a tank 14 for storing the refrigerant liquid and preventing the air from circulating inside the circulation path. It is comprised by.

  A thermal sheet (not shown) for efficiently conducting heat is sandwiched between each thermal head A, B, C and its jacket 5A, 5B, 5C. Both of these are thermally connected. Note that these thermal heads A, B, and C are components having a predetermined life in order to obtain a predetermined performance, and therefore need to be periodically replaced. Therefore, in the present embodiment, in consideration of the ease of replacement of these thermal heads, the surface of the thermal sheet that is in close contact with the thermal head is subjected to a matting process for reducing the adhesiveness.

  Each of the jackets 5A, 5B, and 5C includes a base plate 21 and a U-shaped pipe 22, as shown in FIG. 2 attached thereto. It is joined by attaching. The base plate 21 and the U pipe 22 are made of, for example, an aluminum material having good heat conduction characteristics. Furthermore, each jacket 5A, 5B, 5C is connected by a rubber tube 23 made of a polymer having a low moisture permeability and excellent adhesion to a metal pipe. Since the rubber tube 23 has flexibility, it is easy to remove the jackets 5A, 5B, and 5C when replacing the thermal heads A, B, and C. Although the rubber tube 23 is formed of a member having a low moisture permeability, the refrigerant liquid slightly evaporates from the surface thereof, so that the refrigerant liquid is a sufficient liquid in anticipation of this evaporation. The quantity is stored and held in the tank 14. Further, the tank 14 has a structure in which the suction-side port 141 is disposed at a position lower than the liquid level 142 inside the tank, thereby preventing air from accumulating inside the refrigerant liquid circulation path.

  Here, in the liquid cooling type cooling device having a plurality of jackets, there are cases where the flow paths of the refrigerant liquid to the jackets are connected in parallel (parallel) and in series (serial). It is done. However, in the present invention, the flow direction of the refrigerant liquid flows from the pump 13 in the order of the jacket 5A, the jacket 5B, and the jacket 5C, and then to the tank 14 and the radiator 11, so-called serial flow paths. Is configured. In this way, the connection between the jackets 5A, 5B, and 5C is made serial (in series), thereby simplifying the connection by the tube and thereby shortening the tube length. The shorter the tube length is, the more the amount of refrigerant liquid evaporated from the surface thereof can be suppressed, whereby the tank 14 can be reduced in size and cost. However, when the connection between the jackets 5A, 5B, and 5C is made serial (in series), the flow path resistance increases. However, in response to this, in the present embodiment, the pump 13 has a piston type with a high discharge pressure. Is used. The pump may be a pump having a high discharge pressure, and is not necessarily limited to the piston type. For example, a gear type, vane type, or vortex type pump may be used.

  Further, as will be described in detail later, in the present invention, a plurality (three) of the jackets are arranged in the order of the jacket 5A, the jacket 5B, and the jacket 5C from the upstream side with respect to the direction in which the refrigerant liquid flows. On the other hand, these jackets are arranged in the order of thermal head C, thermal head B, and thermal head A in the conveyance direction of the recording paper 2. That is, the relationship between these plural (three) thermal heads and the plural (three) jackets for cooling them is the order in which the refrigerant liquid flows, in other words, the order in which the refrigerant liquid flows through the plurality of jackets. The order of the recording paper 2 in the transport direction, in other words, the order of recording on the recording medium by a plurality of thermal heads is arranged to be reversed.

  Further, by arranging the tank 14 on the upstream side of the pump 13, air is prevented from entering the pump 13, thereby avoiding the performance of the pump being reduced. That is, when the refrigerant liquid evaporates from the rubber tube 23, air enters and accumulates inside the tube, and the accumulated air flows into the tank 14 as the refrigerant liquid circulates and is stored in the tank 14. become. Therefore, air does not enter the pump 13, and therefore the pump performance is not deteriorated. Further, since the radiator 11 is arranged on the upstream side of the pump 13, the refrigerant liquid cooled by the radiator 11 flows through the pump 13, and the pump can be kept at a low temperature. And is advantageous in terms of reliability.

  Next, in the printing machine according to the present invention, the cooling of the thermal heads A, B, and C by the cooling device 100 will be described in detail with reference to FIGS. FIG. 3 is a partially enlarged side view for illustrating the configuration around the jacket in the printing press according to the present invention. In particular, a state in which the heat of the heating element 20 constituting the thermal head is transmitted to the recording paper 2 is shown. In FIG. 3, as in FIG. 2, the description of the ink ribbon is omitted for ease of explanation, and a roll shape among a plurality (three) of thermal heads A, B, and C is used. Two thermal heads B and C close to the recording paper 2 are typically shown.

  Here, as clearly shown in FIG. 2, the heat generated in the thermal heads A, B, and C is transferred to the respective base plates 21 via the thermal sheet, and further transferred to the U pipe 22 so that the U Heat is transferred to the refrigerant liquid flowing in the pipe 22. The heat transferred to the refrigerant liquid reaches the radiator 11 by circulating and transferring the refrigerant liquid, and is radiated to the cooling air (air) there. In order to improve the heat dissipation performance, the radiator 11 has a flat tube (not shown) through which a refrigerant liquid flows, and a corrugated fin (not shown) around it. It is fixed by. Heat dissipation in the radiator 11 is performed by blowing air from the fan 12. The fan 12 that blows air to the heat radiating surface of the radiator 11 is disposed so as to face the radiator 11. The radiator 11 is attached to the inner wall surface of the casing of the printing press 1 and is arranged so that the ventilation by the fan 12 is directed from the inside of the apparatus to the outside. That is, the heat of each of the thermal heads A, B, and C is transferred to the radiator 11 and radiated from the radiator 11 to the outside of the housing by the ventilation of the fan 12, so that the heat of the thermal head is dissipated inside the device. It will never be done.

  A roll-shaped recording sheet 2 is disposed in the vicinity of the fan 12 inside the casing of the printing press 1 so as to face the fan 12. According to this, the low-temperature intake air generated by the fan 12 flows around the recording paper 2, so that the temperature of the recording paper 2 can be kept low.

  Next, the state of heat conversion between a plurality of (3) thermal heads arranged in series (in series) and the jacket will be specifically described below. As described above, for convenience of explanation, the relationship between the two thermal heads B and C and the jackets 5B and 5C will be described.

As shown in FIGS. 2 and 3 above, if the heat generation amounts of the heat generating elements of the thermal heads are W1 and W2, the heat generation amounts (W1, W2) of these heat generating elements are recorded on the recording paper 2 together with the jackets 5B and 5C. Since heat is transferred, the relationship between the heat transfer heat amounts (Ww1, Ww2) to the jackets 5B and 5C and the heat transfer heat amounts (Wp1, Wp2) to the recording paper is expressed by the following (Formula 1).
W1 = Ww1 + Wp1
W2 = Ww2 + Wp2 (Formula 1)

  Further, the temperature of the heating element of each thermal head is Th1, Th2, the temperature of the refrigerant liquid entering the upstream jacket 5B is Tw1, and the temperature of the refrigerant liquid entering the downstream jacket 5C is Tw2.

Here, the relationship between the temperature (Tw1) of the refrigerant liquid entering the upstream jacket 5B and the temperature (Tw2) of the refrigerant liquid entering the downstream jacket 5C is that the refrigerant liquid entering the downstream jacket 5C is only ΔTw compared to the upstream side. If it becomes high, it is shown by the following (Formula 2).
Tw2 = Tw1 + ΔTw (Formula 2)

The amount of heat received by each jacket (Ww1, Ww2) is expressed by the following (Equation 3).
Ww1 = (Tw1-Th1) / Rj
Ww2 = (Tw2-Th2) / Rj = (Tw1 + ΔTw-Th2) / Rj (Formula 3)
Here, Rj: thermal resistance value (constant) of the jacket.

  Here, if the amount of heat (Ww1, Ww2) received by each of the jackets 5B, 5C is the same (Ww1 = Ww2), in the above (Equation 3), Th2 = Th1 + ΔTw. That is, the temperature of the heating element in the downstream jacket increases by ΔTw.

On the contrary, in order to set the temperature of the heat generating element of the downstream thermal head to the same temperature as when not affected by the heat from the upstream jacket 5B, that is, (Th1 = Th2), the downstream jacket The amount of heat received by 5C (Ww2) must be less than the amount of heat received by upstream jacket 5B (Ww1). This is expressed by the following (Formula 4) by setting Th1 = Th2 in the above (Formula 3).
Ww2 = Ww1- △ Tw / Rj (Formula 4)

  As described above, when the amount of heat received by each jacket is equal, the temperature of the heating element of the downstream jacket 5C rises by ΔTw compared to the upstream side, and conversely, the temperature of each heating element is kept equal. In order to achieve this, it is necessary to reduce the amount of heat received by the downstream jacket 5C by ΔTw / Rj.

  Next, heat transfer to the recording paper 2 will be described. As shown in FIG. 3, the recording paper 2 is conveyed while receiving heat from the heat generating element of the thermal head. Therefore, the thermal head located on the downstream side in the conveyance direction of the recording paper 2 is the recording paper 2. Printing is performed on the recording paper 2 heated by the thermal head upstream in the transport direction.

Therefore, the relationship between the temperatures (Tp1, Tp2) of the recording paper 2 is expressed by the following (Equation 5), where ΔTp is the temperature rise due to the heating element of the thermal head upstream in the conveyance direction of the recording paper 2.
Tp1 = Tp2 + ΔTp (Formula 5)

Further, the heat transfer amounts (Wp1, Wp2) to the recording paper are expressed by the following (Equation 6).
Wp1 ＝ α ・ λ (Th1－Tp1)
Wp2 ＝ α ・ λ (Th2－Tp2)
= α ・ λ (Th2－Tp1) + α ・ λ ・ △ Tp (Formula 6)
Where α is a constant and λ is the thermal conductivity of the recording paper.

  The above (Equation 6) indicates that the lower the temperature (Tp1, Tp2) of the recording paper 2, the greater the amount of heat transfer to the recording paper 2 side.

Further, when the temperatures (Th1, Th2) of the respective heating elements are equal, the following (Expression 7) is obtained by setting Th2 = Th1 in (Expression 6).
Wp2 = Wp1 + α · λ · ΔTp (Formula 7)

  In the above (Equation 6), the amount of heat transfer to the recording paper 2 is larger by α · λ · ΔTp on the upstream side (Wp2) of the recording paper 2 than on the downstream side (Wp1). Indicates.

Here, in the present invention, the thermal head on the downstream side of the refrigerant liquid is positioned on the upstream side in the conveyance direction of the recording paper 2. As a result, the condition for equalizing the temperatures (Th1, Th2) of the heat generating elements of the thermal head, that is, reducing the amount of heat received by the downstream jacket 5C by ΔTw / Rj reduces the amount of heat transfer to the recording paper. It can be realized by increasing it. The condition for this is that, when the heat generation amounts (W1, W2) of the heat generating elements are substantially equal, the following (Formula 8) is obtained from the above (Formula 1), (Formula 4), and (Formula 7). Can be summarized as:
△ Tw / Rj = α ・ λ ・ △ Tp (Formula 8)

  As shown in the above (Expression 8), as the thermal conductivity λ of the recording paper 2 is higher, the amount of heat transfer to the recording paper 2 side increases, so the amount of heat received by the downstream jacket 5C is reduced. I can do it. That is, since the thermal conductivity of paper generally increases as the specific gravity increases, the amount of heat transferred to the recording paper 2 can be increased by using a paper having a high specific gravity, and thus the refrigerant It is possible to further reduce the amount of heat received by the downstream jacket 5C of the liquid.

In the present embodiment, for example, a paper having a high specific gravity (coated paper coated with paint on the surface) having a thickness of 0.1 mm or more and a weight of 104 g / m ² or more is used. As a result, in the present embodiment, the amount of heat released to the recording paper 2 side is 5 to 10 W greater in the downstream thermal head than in the upstream side. Further, as described above, the temperature of the recording paper 2 is kept low by the intake air from the fan, so that the amount of heat transfer to the recording paper 2 side is increased. Furthermore, in the above-described embodiment, the recording paper 2 has been described only as being rolled, but instead of this, a plurality of sheets may be stacked.

As described above, according to the present invention, by adopting a liquid cooling system cooling means that simplifies piping by connecting each jacket corresponding to a plurality of thermal heads in series (series), The heat of multiple (three) thermal heads, which is the main heat source inside the printing press, is released to the outside of the printing press without being scattered inside the casing of the device, and for radiator cooling. The temperature of the recording medium (paper) is kept low by the intake air of the fan, and the temperature of the recording medium (paper) kept at this low temperature tends to increase from its configuration and the downstream side of the refrigerant flow By conveying in order from the head, an increase in the temperature of the downstream thermal head is suppressed, thereby enabling an increase in printing speed.

  In the present embodiment, a roll-shaped recording sheet is arranged as a recording medium in the vicinity of the intake air of the fan. However, the present invention is not limited to this, and heat from other heat sources other than the thermal head is used. Therefore, any structure can be used as long as the temperature of the recording medium is kept low. In the above embodiment, the thermal transfer type printing apparatus using the ink ribbon has been described as an example of the printing apparatus. However, the present invention is not limited to this, and the printing of the type in which the recording medium itself reacts thermally. It may be a device.

1 is a diagram illustrating an overall schematic configuration of a printing press according to an embodiment of the present invention. It is a partially expanded perspective view which shows the structure of the jacket periphery in the said cooling device. It is a partially expanded side view which shows the structure of the jacket periphery in the said cooling device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printing machine, 2 ... Recording paper, 3 ... Pinch roller, 4 ... Control circuit, 5 ... Jacket, 6 ... Ink ribbon, 7 ... Ink ribbon winding roll, 8 ... Platen roller, 9 ... Cutter, 10 ... Tray, DESCRIPTION OF SYMBOLS 11 ... Radiator, 12 ... Fan, 13 ... Pump, 14 ... Tank, 141 ... Suction side port inside tank, 142 ... Liquid level inside tank, AC ... Thermal head, 15 ... Fan wind, 20 ... Thermal head Heating element, 21 ... base plate, 22 ... U pipe, 23 ... rubber tube, 100 ... cooling device.

Claims (6)

Means for transporting a recording medium placed inside the housing in a predetermined direction;
A plurality of thermal heads arranged along the conveyance direction of the recording medium conveyed by the means; and
In a printing machine that has a cooling device for cooling the plurality of thermal heads in a housing, and sequentially transports the recording medium along the plurality of thermal head portions to perform printing,
The cooling device is
A plurality of heat receiving members that are thermally connected to each of the plurality of thermal heads to receive the heat of the thermal heads and that are serially arranged to form a circulation path for the refrigerant liquid;
A heat dissipating part that has at least a fan, and is disposed in the vicinity of the casing, and dissipates heat from the plurality of heat receiving members via a radiator;
A pump for circulatingly driving the refrigerant liquid;
A piping member arranged to circulate the refrigerant liquid between the plurality of heat receiving members, the heat radiating portion, and the pump; and
Means for holding the recording medium placed inside the housing at a low temperature;
A printing machine, wherein an order of recording by the plurality of thermal heads on the recording medium being conveyed and an order in which the refrigerant liquid circulates to the plurality of heat receiving members are reversed.   2. The printing press according to claim 1, wherein the means for holding the recording medium constituting the cooling device at a low temperature includes the fan of the heat radiating unit, the radiator disposed in the vicinity of the casing, and the casing. A printing machine comprising a recording medium placed inside a body and disposed at a position facing both of the recording media.   3. The printing press according to claim 2, wherein in the cooling device, the plurality of heat receiving members are further connected using a polymer tube having flexibility, and a circulation path for the refrigerant liquid A printing machine characterized in that a gas-liquid separation means is provided.   4. The printing press according to claim 3, wherein each of the plurality of heat receiving members constituting the cooling device includes a plate-like member thermally bonded to the thermal head and a U-shaped pipe. A printing machine characterized by that.   5. The printing press according to claim 4, wherein a tank for storing the refrigerant liquid therein is used as the gas-liquid separation means, and the tank is a part of the circulation flow path and is upstream of the pump. A printing machine characterized by being provided on the side.   6. The printing press according to claim 5, wherein the plurality of thermal heads are three, and the plurality of heat receiving members that receive heat from the thermal head are also three.

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