JP3691324B2 - Double thermal printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing apparatus and a multiple printing apparatus capable of printing on a plurality of sheets, and relates to a technique effective for use in, for example, a thermal printing apparatus (so-called thermal printer) having a thermal head.
[0002]
[Prior art]
Printers used as information output devices include an impact method such as a wire dot printer and a non-impact method. Further, non-impact printers include laser printers and thermal printers. Of these, impact type printers are noisy and have poor print quality, so in recent years non-impact type printers have become widely used. Among non-impact printers, thermal printers are suitable for miniaturization, and are therefore used in a wide range of fields.
[0003]
In particular, in a POS (Point Of Sales) terminal, it is necessary to print two sheets of output paper for a receipt to be handed over to a customer and output paper for a journal to be left as a copy of a store at the same time. The installed printer and the duplex printer having two heads have been put into practical use. However, since the cost of a print head is considerably high in a printer, a multiple printer having a head corresponding to each sheet can achieve downsizing to some extent, but a sufficient effect in terms of cost has not been obtained.
[0004]
In view of this, an invention relating to a double thermal printer has been proposed in which a thermal head is shared and two paper feed units are provided side by side with respect to the common thermal head, thereby reducing the size and improving the economy. (Patent No. 2819595).
[0005]
[Problems to be solved by the invention]
However, although the thermal printer according to the invention of the prior application has an advantage that it is an inexpensive device capable of simultaneously printing on two sheets of paper, the drive roller and the motor are one and the sheet feed mechanism is Since the guide part is fixed, the width of the paper to be printed is fixed, and the printing speed must be the same in the two systems, which reveals that there is a problem of low versatility. .
[0006]
In particular, in a POS terminal, there are many cases where it is desired to change the information to be output and the amount of the output paper for receipts to be handed over to customers and the output paper for journals to be kept at the store. Therefore, when the thermal printer according to the above-mentioned prior application is used for a POS terminal, two types of printers having different size ratios of the two sheets must be prepared, and a significant cost reduction cannot be achieved. .
[0007]
Moreover, since the thermal printer according to the above-mentioned prior application patent invention has one drive roller and one motor, the printing speed for two sheets cannot be changed. For this reason, it has been found that when the difference in the amount of output information is large, that is, when the amount of information is extremely different, there is a problem that the paper with the smaller amount of information has a larger margin and is wasted.
[0008]
An object of the present invention is to provide a double thermal printer that can change the size ratio of the paper to be used, thereby reducing the total cost.
[0009]
Another object of the present invention is to make it possible to change the printing speed for two sheets of paper, so that even if there is a large difference in the amount of output information, it is possible to cope with two series without changing the size ratio of the sheets so much. It is to provide a thermal printer of the type.
[0010]
Still another object of the present invention is to provide a double-type thermal printer that can avoid the occurrence of waste due to an increase in margins on a sheet having a smaller amount of information.
[0011]
[Means for Solving the Problems]
The present invention has been made paying attention to the above-described problems, and is two platen rollers that are positioned on the same axis and opposed to one thermal head, and are independently rotatably supported. And a paper feed means for separately transferring the thermal paper inserted between the platen roller and the thermal head, and holding the thermal head and at both ends of the thermal paper. And a movable frame that includes a regulating piece that regulates the movement of the platen roller and is slidable in the axial direction of the platen roller.
[0012]
In the above configuration, the platen shape is preferably a roller platen, but may be another already proposed shape. For example, it may be convex in the platen direction, non-cylindrical and non-rotating, or flat. In this case, the platens are juxtaposed with the thermal head, and are arranged side by side in the line direction in which the heat generating elements of the thermal head are arranged. The movable frame is also slidably attached in this line direction.
[0013]
Further, the regulating piece for regulating the edge of the thermal paper is preferably provided on the movable frame, but may be provided on another member. In this case, it is preferable to provide the restriction piece so that it can slide in the same direction as the sliding direction of the movable frame.
[0014]
The movable frame is preferably slid to the end on the side wall side of the main body frame and fixed at this position, but it is slid to an arbitrary position according to the width of the thermal paper to be used and fixed to be fixed at that position. Means may be provided. The fixing means may be a convex portion provided on the movable frame and a slit structure provided on the main body frame side so as to be opposed thereto, or in a gap formed between the movable frame and the side wall portion of the main body frame. The stopper may be inserted. In this case, the stopper is made of a conductive material and grounded to the reference potential on the main body frame side, so that the static electricity generated by friction between the head and the thermal paper is released to the ground. You may comprise as follows.
[0015]
According to the above-described means, the paper size to be used can be changed simply by sliding the movable frame. Further, since the paper feeding means for separately feeding the two platens (preferably the platen roller) and the thermal paper is provided, the paper feeding speed of the two thermal papers can be changed.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the drawings.
[0017]
1 is a perspective view showing an embodiment of a thermal printer according to the present invention, FIG. 2 is a sectional side view showing a state in which the thermal head is separated from a platen roller, and FIG. 3 is a state in which the thermal head is pressed against the platen roller. FIG.
[0018]
In FIG. 1, 100 is a printer, 1 is a main body frame of the printer, 2a and 2b are platen rollers mounted on the front end of the main body frame 1, and 3 is a main body that can be moved toward and away from the platen rollers 2a and 2b. A lined-dod thermal head 4 attached to the frame 1 is a rotation pressing member for moving the thermal head 3 toward and away from the platen roller 2. The rotary pressing member 4 has a pressing piece 4a located on the back surface of the thermal head 3 and an operating lever 4b provided on one side so as to protrude upward. The main body frame 1 is made of plastic, and the platen rollers 2a and 2b have outer peripheral surfaces covered with an elastic material.
[0019]
As shown in FIG. 2, the thermal head 3 is fixed between a pair of left and right head support pieces 6a and 6b fitted to a head support shaft 5 disposed at the lower center of the main body frame 1, and the head support shaft. 5 is held so as to be rotatable about the center. 2, the thermal head 3 is separated from the platen roller 2 as shown in FIG. 2, and is pushed by the platen rollers 2a and 2b by tilting the operation lever 4b forward as shown by an arrow B in FIG. It is configured as follows.
[0020]
Although not particularly limited, in this embodiment, a plurality of leaf springs 7 are fixed to the back surface of the thermal head 3, and the front end side of the leaf springs 7 is a rear wall of a movable frame 20 described later. 25. Accordingly, when the operating lever 4b is pushed forward, the pressing piece 4a is rotated while the leaf spring 7 is pushed forward while being bent as shown in FIG. The platen roller 2 is configured to be pressed with a predetermined pressure by an elastic force.
[0021]
Further, as shown in FIG. 2, a push-up piece 4c is provided at the lower end of the operation lever 4b, and an engagement pin 3a is provided on one side of the thermal head 3 so as to protrude sideways. When the operation lever 4b is rotated rearward as indicated by an arrow A, immediately after the pressing piece 4a is separated from the leaf spring 7, the pushing piece 4c comes into contact with the engaging pin 3a and lifts it up. Thus, the thermal head 3 is forcibly separated from the platen roller 2.
[0022]
In this embodiment, as shown in FIG. 1, the platen roller 2 is supported by a rotary shaft 8a between a side wall 1a of the main body frame 1 and a support wall 1c erected at the center of the front end of the frame. One platen roller 2a, and a second platen roller 2b supported by a rotating shaft 8b between the side wall 1b and the support wall 1c are divided into two. Although not particularly limited, in this embodiment, the platen roller 2a is formed shorter than 2b.
[0023]
Drive motors 9a and 9b are attached to the rear end portions on both sides of the main body frame 1 in accordance with the two divided platen rollers 2a and 2b. The rotational driving force of the drive motors 9a and 9b is configured to be transmitted to the platen rollers 2a and 2b by gear reduction mechanisms built in the side walls 1a and 1b of the main body frame 1, respectively.
[0024]
Note that a pin 10 laid horizontally above the platen roller 2a between the side wall portion 1a and the support wall 1c of the main body frame 1 slightly above is a stopper for restricting the front position of the operation lever 4b. It is a pin for. The pin 10 also has a function of guiding the printed paper at a desired angle with respect to the cutter when the cutter is attached in front of the platen roller 2b. The reason why the pins 10 are provided only on the platen roller 2a side is that the left-side paper is used for a journal that is left as a record in the store when used in a POS terminal, and the right-side paper is delivered to the customer. This is because it is assumed that the cutter is attached only on the right side for use in the receipt.
[0025]
On the other hand, as shown in FIG. 1, the thermal head 3 is formed as a single body so as to face the platen rollers 2a and 2b, but the length thereof is the width of the platen roller 2a and the width of 2b. It is designed to be slightly shorter than the total length of the platen rollers 2a and 2b. The difference between the length of the thermal head 3 and the total length of the platen roller is determined according to the thermal head slide amount described later. In other words, the length of the thermal head 3 may be a length obtained by subtracting the sliding amount of the thermal head from the entire length of the platen roller.
[0026]
Next, the slide mechanism of the thermal head 3 will be described.
[0027]
In this embodiment, a movable frame 20 made of a conductive material is attached to the lower surface of the front end of the main body frame 1, and the movable frame 20 has a pair of holding pieces bent upward at both ends as shown in FIG. 21a and 21b are formed, and through holes 22a and 22b formed in the lower portions of the holding pieces 21a and 21b are fitted to the head support shaft 5 so that the body frame 1 can slide in the left-right direction. It is configured. Further, a support pin 11 that supports the rotation pressing member 4 so as to be rotatable is horizontally placed between engagement holes 23a and 23b formed at the distal ends of the holding pieces 21a and 21b.
[0028]
The pair of left and right head support pieces 6a and 6b that support the thermal head 3 are fitted to the head support shaft 5 inside the holding pieces 21a and 21b at both ends of the movable frame 20, and the operation lever 4b. When the movable frame 20 is moved along the head support shaft 5 in the state shown in FIG. 2, the holding pieces 21a and 21b push the head support pieces 6a and 6b laterally to bring the thermal head 3 together. It is configured to slide.
[0029]
Further, the movable frame 20 is provided with restricting pieces 24a and 24b for restricting the end of the sheet, and the sheet used is determined by the distance between the restricting pieces 24a and 24b and the support wall 1c at the front end of the main body frame 1. The width is determined. Accordingly, when the movable frame 20 is slid, the intervals between the regulating pieces 24a and 24b and the support wall 1c change simultaneously, so that the width of the sheet fed by the platen rollers 2a and 2b is changed.
[0030]
Specifically, when the movable frame 20 is moved to the left side in FIG. 1, the distance between the regulating pieces 24a and 24b and the support wall 1c is the same, and the thermal paper for printing having the same width between the platen rollers 2a and 2b. In a state where the movable frame 20 is moved to the right side in FIG. 1, the interval between the restricting piece 24a and the support wall 1c is narrowed, and the interval between the restricting piece 24b and the support wall 1c is widened, and the platen roller 2a. Is configured to feed a thermal paper for printing having a narrow width, and the platen roller 2b is configured to feed a thermal paper for printing having a width wider than that of the platen roller 2a. That is, by sliding the movable frame 20 to the left or right, the combination of the widths of the thermal paper to be used can be changed.
[0031]
Moreover, in this embodiment, the restricting pieces 24 a and 24 b are formed so that the lower ends thereof are in contact with the guide wall 1 d provided at the front end of the main body frame 1. Further, at the front end of the movable frame 20, guide pieces 25 a and 25 b facing the side front walls 1 e and 1 f of the main body frame 1 are erected. As a result, the rotation of the movable frame 20 around the head support shaft 5 is restricted, and the movable frame 20 can slide to the left and right in a stable posture.
[0032]
Although not particularly limited, in this embodiment, a gap formed between the movable frame 20 and the inner surface of the side wall of the main body frame 1 in a state where the movable frame 20 is moved to either one end. A stopper / conduction member 30 having a shape as shown in FIG. 5 made of a conductive metal plate or the like at C2 (or C1) is detachably inserted from below the main body frame 1. The gap formed between the movable frame 20 and the inner surface of the side wall of the main body frame 1 is indicated by reference numeral C2 in FIG. 1, but the movable frame 20 is slid to the right end as opposed to FIG. Then, such a gap C1 is generated on the opposite side (left side), and the stopper / conduction member 30 has a symmetrical shape that can be inserted into either the left or right gap.
[0033]
The substantially rectangular notch 31 at the lower front portion of the stopper / conduction member 30 shown in FIG. 5 is formed so as to be engageable with the head support shaft 5, and is formed from both ends of the center toward the center. The notches 32 and 33 are for facilitating the flexure of the wing pieces 34 and 35 during attachment and detachment. Further, the stopper / conduction member 30 is provided with a contact piece 36 extending obliquely downward from the upper end, and locking pieces 37, 38 bent outward from the tip portions of both wing pieces 34, 35. Yes.
[0034]
Of these, the locking pieces 37 and 38 are engaged with engagement holes formed in the vicinity of the motor mounting portion on the inner surface of the side wall portion of the main body frame 1 to prevent displacement of the stopper / conduction member 30. On the other hand, the contact piece 36 is pressed into contact with the metallic housing of the drive motor 9a or 9b by the elasticity of the stopper / conduction member 30 in the state of being inserted into the gap C1 or C2.
[0035]
The blades 34 and 35 of the stopper / conduction member 30 are in contact with the holding pieces 21a and 21b at both ends of the movable frame 20, and when the thermal head 3 is pressed against the platen rollers 2a and 2b by the movable frame 20. Are assembled so that the tip of the leaf spring 7 on the back is in contact therewith. As a result, the housing of the drive motor 9a or 9b and the thermal head 3 are electrically set to the same potential. Further, as shown in FIG. 1, the inner wall inner surface of the side wall 1b (1a) of the main body frame 1 has a protrusion 51 whose front end protrudes from the side front wall 1f (1e) at the front end, A sheet metal 50 formed so as to reach the mounting position of the drive motor 9b (9a) is attached, and the drive motor 9b (9a) is fixed to the sheet metal 50 with a screw and the guide of the movable frame 20 The piece 25b (25a) is configured to be contactable. As a result, the drive motor 9a or 9b on the side where the stopper / conduction member 30 is not inserted and the movable frame Mu 20 and the same potential through the sheet metal 50. These are grounded by a ground wire (not shown) to prevent the thermal head from being damaged by static electricity.
[0036]
2 and 3, reference numeral 42 denotes a detector comprising a micro switch for detecting whether the thermal head 3 is in the up state or the pressed state.
[0037]
Next, a method for using the thermal printer of the above embodiment will be described.
[0038]
In the thermal printer of the embodiment, the movable frame 20 is moved to the left end and the stopper / conduction member 30 is inserted into the gap C2, and the movable frame 20 is moved to the right end and the gap on the opposite side. There are two setting states of the second setting state in which the stopper / conduction member 30 is inserted in (C1). Of these, in the second setting state, the effective printing width of the left platen roller 2a is narrower than in the first setting state, and conversely, the effective printing width of the right platen roller 2b is widened.
[0039]
Moreover, the thermal printer of this embodiment is provided with drive motors 9a and 9b for the platen rollers 2a and 2b, respectively. Therefore, the platen rollers 2a and 2b can independently control the paper feed amount, that is, the printing speed and the size of the printed characters. As a result, unlike the conventional thermal printer, it is not necessary to prepare two types of apparatuses having different ratios of the widths of two printing sheets, and a printer having a different ratio of the widths of two printing sheets in one unit. Can be provided, and the total cost can be reduced.
[0040]
In the embodiment, by inserting the stopper / conduction member 30 into the gap C1 or C2 generated between the movable frame 20 and the side wall portion of the main body frame 1 in a state where the movable frame 20 is slid to one end, Although the movable frame 20 is prevented from moving in the lateral direction during operation, the means for preventing movement of the movable frame 20 is not limited thereto.
[0041]
For example, in the embodiment shown in FIG. 1, when the movable frame 20 is moved to the left end or the right end, the engagement slit 1g is engaged with the front end surface of the main body frame 1 facing the restriction piece 24a or 24b (the right side slit is engaged with the restriction piece 24b). The movable frame 20 can be prevented from moving only by the engagement slit 1g. However, as in the embodiment, the movement of the movable frame 20 can be prevented more reliably by inserting the stopper / conduction member 30 into the gap C1 or C2 formed between the side wall of the main body frame 1 and the like. be able to.
[0042]
In the embodiment, the driving force of the driving motor is transmitted to the platen roller and rotated. However, a paper feed roller may be provided separately from the platen roller.
[0043]
In the embodiment shown in FIG. 1, the sheet size is changed by moving the movable frame 20 to either the left end or the right end, but the movable frame is configured to be fixed at an arbitrary position. May be.
[0044]
FIG. 6 is a perspective view of a thermal printer 100 ′ according to another embodiment having such a configuration. In this embodiment, the movable frame 20 can be fixed at several positions in the width direction. Reference numeral 1g ′ denotes an engagement slit provided in the guide wall 1d ′, which is different from the above embodiment in that a plurality of slits are provided in the width direction. The movable frame 20 has restriction pieces 24a and 24b as in the above-described embodiment, and the movement in the lateral direction is fixed by the restriction pieces getting stuck in the engagement slit 1g ′. Since a plurality of engagement slits 1g ′ are provided, the movable frame 20 can be fixed at a desired position where the slits exist. According to this configuration, more combinations of sheets than the combinations of sheets that can be used in the above embodiment can be used, and the degree of freedom with respect to the sheet width can be further increased.
[0045]
Also in this configuration, in order to more reliably fix the movable frame 20, a gap C <b> 1 generated between a stopper and a conducting member (not shown) similar to that in the above embodiment and the side wall portion of the main body frame 1 is also provided. You may comprise so that it may insert in 'or C2'. In this case, since the width of the gap C1 ′ or C2 ′ varies depending on a plurality of positions where the movable frame 20 is fixed, a plurality of stopper / conduction members having a plurality of different widths are prepared. The thermal head 3 can be grounded by inserting this stopper / conducting member, as in the above embodiment.
[0046]
The movable frame 20 may be configured to be fixed at arbitrary positions in the width direction in addition to being configured to be fixed at discrete positions as in the above-described embodiment.
[0047]
In the above-described embodiment, the restricting piece for restricting the edge of the sheet is provided on the movable frame. However, the restricting piece may be provided on another part. FIG. 7 is a perspective view of a thermal printer 100 ″ according to another embodiment having such a configuration. In this embodiment, a slide hole 1h is provided in the guide wall 1d ″, and the restricting pieces 26a, 26b are provided here. It has a structure that fits in and can slide in the horizontal direction. The restricting pieces 26a and 26b are fixed at a position corresponding to the position at which the movable frame 20 ″ is fixed by a fixing mechanism (not shown).
[0048]
The movable frame 20 ″ is provided with a fixed piece 27, and the movable frame 20 ″ is fixed by being fitted into an engagement slit 1g ″ provided on the guide wall 1d ″. As in the previous embodiment, in order to more reliably fix the movable frame 20 ″, a stopper / conduction member (not shown) is configured to be inserted into a gap formed between the side wall of the main body frame. The configuration of the stopper / conduction member and the function of grounding the thermal head are the same as in the above embodiment.
[0049]
In the thermal printer described above, the platen has a structure that rotates in a roller shape, but the platen may have another structure. For example, the present invention can be applied even if the surface facing the thermal head is convex and non-cylindrical and does not rotate or is planar.
[0050]
【The invention's effect】
As described above, the thermal printer according to the first aspect of the present invention is arranged in parallel with the main body frame, one thermal head, and the thermal head, and is positioned on the same axis and can be independently rotated. The first and second platen rollers supported by the paper, paper feeding means capable of separately transferring two thermal papers inserted between the platen roller and the thermal head, and the thermal head. A movable frame that has a pair of regulating pieces for holding and regulating the end of the thermal paper at both ends and is slidably mounted in the axial direction of the platen roller. It is possible to change the paper size to be used and to change the feeding speed of the two papers.
[0051]
According to a second aspect of the present invention, a support wall is provided between the first platen roller and the second platen roller of the main body frame, and the support wall and one side wall portion of the main body frame are provided with the support wall. A support shaft of the first platen roller is horizontally mounted, a support shaft of the second platen roller is horizontally mounted between the support wall and the other side wall portion of the main body frame, and a side surface of the support wall is Since it is configured to form a guide surface that regulates the other end of the two thermal sheets inserted between the first and second platen rollers and the thermal head, the support wall of the platen roller and the thermal sheet Therefore, the structure can be simplified.
[0052]
The invention of claim 3 is provided with a stopper member that can be inserted into any gap formed between the movable frame and the side wall of the body frame in a state where the movable frame is slid to one end. The movement of the movable frame can be surely prevented, and since only one stopper member is required, the number of parts can be reduced.
[0053]
According to a fourth aspect of the present invention, the paper feeding means includes two drive motors provided corresponding to the platen rollers, and two sets of gear reduction mechanisms that respectively transmit the drive force of the drive motors. Therefore, there is an effect that the printing speed for two sheets can be changed and the size of the printed characters can be changed for output.
[0054]
According to a fifth aspect of the present invention, the stopper member is formed of a conductive material, and a part of the stopper member is configured to be brought into contact with a conductive housing of a drive motor constituting the paper feeding means in an inserted state. Therefore, there is an effect that the movable frame and the housing of the drive motor are set to the same potential through the stopper member, and it is easy to take a ground for countermeasures against static electricity.
[0055]
According to a sixth aspect of the present invention, an elastic member that presses the thermal head against the platen roller is disposed on the back surface of the thermal head, and a part of the elastic member is in contact with the movable frame. Since it is configured, the thermal head, the movable frame, and the housing of the drive motor are at the same potential, and it is easy to ground.
[0056]
In the seventh aspect of the invention, the movable frame is configured to have a guide piece that abuts a surface parallel to the support shaft of the platen roller formed on the main body frame. There is an effect that it can be slid.
[0057]
According to an eighth aspect of the present invention, a head up / down mechanism for pressing the thermal head against the platen roller or moving the thermal head away from the platen roller by rotation of an operation lever is provided on the back portion of the thermal head. In the vicinity of the platen roller on the arrangement side, a position regulating pin is provided in parallel with the platen roller to regulate the rotational position of the operation lever, so that the pressing force of the thermal head against the platen roller is made constant. There is an effect that can be.
[0058]
In the ninth aspect of the invention, the operation lever and the position regulating pin are provided in parallel with the platen roller on the side where the width facing the thermal head becomes narrow when the movable frame is slid. The position regulating pin and the sheet guiding member can be used together, and the number of parts can be reduced.
[0059]
According to a tenth aspect of the present invention, since the length of the thermal head is set to be shorter than the length obtained by adding the widths of the first and second platen rollers and the arrangement interval of these platen rollers, the thermal head is minimized. There is an effect that the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a thermal printer according to the present invention.
2 is a cross-sectional side view showing a state in which a thermal head in the thermal printer of the embodiment of FIG. 1 is separated from a platen roller.
3 is a cross-sectional side view showing a state in which a thermal head in the thermal printer of the embodiment of FIG. 1 is pressed against a platen roller.
FIG. 4 is a perspective view showing a specific example of a movable frame.
FIG. 5 is a perspective view showing a specific example of a stopper / conduction member inserted into a gap formed between the movable frame and the main body frame.
FIG. 6 is a perspective view showing a second embodiment of the thermal printer according to the present invention.
FIG. 7 is a perspective view showing a third embodiment of the thermal printer according to the present invention.
[Explanation of symbols]
1 Body frame
1a, 1b side wall
1c Support wall
1d, 1d ', 1d "guide wall
1e, 1f Side wall
1g, 1g ', 1g "slit for engagement
1h Slide hole
2a, 2b Platen roller
3 Thermal head
3a engaging pin
4 Rotating pressing member (head up / down mechanism)
4a Pressing piece
4b Operation lever
4c Push-up piece
5 Head support shaft
6a, 6b Head support piece
7 leaf spring
8a, 8b Rotating shaft
9a, 9b Drive motor
10 pins
11 Support pin
20,20 "movable frame
21a, 21b Holding piece
22a, 22b Through hole
23a, 23b engagement hole
24a, 24b Restriction piece
25a, 25b Guide piece
26a, 26b Restriction piece
27 Fixed piece
30 Stopper and conductive member
31, 32, 33 Notch
34, 35 both wing pieces
36 Contact piece
37, 38 Locking piece
41 connector
42 Detector
50 sheet metal
51 protrusion
100, 100 ', 100 "printer

Claims (1)

  A main body frame, one thermal head, first and second platen rollers which are arranged in parallel with the thermal head and are rotatably supported independently of each other, and these platens A paper feeding means capable of separately transferring two thermal papers inserted between the roller and the thermal head, and a pair of regulations for holding the thermal head and regulating the ends of the thermal paper at both ends. A duplex thermal printer comprising: a movable frame having a piece and slidably mounted in the axial direction of the platen roller.

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