JPS63209868A - Serial thermal printer - Google Patents

Abstract

PURPOSE:To prevent rotation of a platen at the time of setting a priting medium by forming a protrusion jutting out toward a thermal head provided at one end of the platen and the corresponding arm on a carriage. CONSTITUTION:When a thermal head 44 is located at a normal printing position (a) with the first carriage 54 and the second carriage 59, the thermal head 44 is in close contact with an elastomer 38 of the platen 37. If the carriage is moved to a home position (b) side by guidance of a lower guide shaft 51 for setting a printing medium, an arm 63 provided on the carriage 59 gradually climbs up a protrusion 39 provided on a fulcrum 42 of the platen 37. Then if the arm 63 is set to the end of a climbing action on the protrusion 39, the thermal head 44 is separated by a fixed value of distance from the elastomer 38 and the platen 37 is retained in a state where it cannot rotate, by the pressing force of the protrusion 39 and arm 63. Consequently, the printing medium is stabilized and thereby paper can be loaded between the platen and thermal head.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a serial thermal printer used as an output mechanism for various information processing devices, etc. In particular, the present invention relates to a serial thermal printer used as an output mechanism for various information processing devices. This invention relates to a serial thermal printer having a structure in which printing media are loaded at a distance.

[Conventional technology]

As is well known, a serial thermal printer presses a thermal head against a printing medium such as thermal paper whose back side is supported by a platen when printing, and prints on the printing medium while moving this thermal head together with a carriage. The structure for setting the print medium in such a serial printer is to separate the thermal head from the platen at a desired position using an opening mechanism consisting of a release lever and a link mechanism, and to close the gap created by this (platen gap). ) is used to load the print medium between the two.

However, in cases where it is not possible to have the above-mentioned platen opening mechanism due to space constraints, such as in a built-in ultra-compact serial thermal printer, the thermal head is always in pressure contact with the platen in the normal printing area. By returning the thermal head to the home position together with the carriage when setting the print medium, the thermal head is automatically separated from the platen by a mechanical structure, and the print medium can be loaded between the thermal head and the platen. has been adopted.

9 is a side sectional view showing a conventional serial thermal printer having the above-described structure, FIG. 10 is an enlarged perspective view of the carriage in FIG. 9, and FIG. 11 is an enlarged perspective view of the thermal head in FIG. 9, FIG. 12 is a plan view of the main part of FIG. 9.

In the figure, 1 is the printer frame, 2 is the platen,
The front of this platen 2 is a flat elastic body 3 made of heat-resistant rubber, etc.
The frame 1 is formed with mounting holes provided at both ends, and by fitting the support bins 4 press-fitted from both sides of the upper part of the frame 1 into the respective mounting holes, the support bins 4 can be placed at the center. It rotates at a constant angle as shown in FIG.

5 is a thermal head, a flexible cable 6 is connected to this thermal head 5, and the flexible cheese flavor 6-? Drive energy is transmitted from a control means (not shown) through the intermediary 1.

- Also, the thermal head 5 is adhered to the heat sink 7 using a projection 8 provided on one side of the heat sink 7 as a positioning reference, and two types of projections 9 and 10 are provided on both sides of the heat sink T. It is located in the positional relationship of

11 is an upper guide shaft, 12 is a lower guide shaft, and both ends of the shafts 11 and 12 are supported on both sides of the frame 1 so as to be parallel to each other.

Reference numeral 13 denotes a drive shaft located between the upper guide shaft 11 and the lower guide shaft 12, which has a spiral groove 14 on its outer peripheral surface, and is supported on both sides of the frame 1. It is rotated by a space motor (not shown).

Reference numeral 15 denotes a first carriage, and the first carriage 15 is provided with three holes, through which the guide shaft 11, 12 and the drive shaft 13 pass, and the upper guide shaft 11 is inserted into each hole. The hole 16 through which it passes is vertically long.

Reference numeral 17 denotes a feed pin attached to the first carriage 15. The tip of the feed pin 17 protrudes in the direction through which the drive shaft 13 passes, and engages with the groove 14 of the drive shaft 13, thereby causing the drive shaft. When the shaft 13 rotates, the feed pin 1
7 and the groove 14 allows the first carriage 15 to move on the drive shaft 13.

18 is a protrusion provided on the back surface of the first carriage 15;
9 is a cable clamp.

Reference numeral 20 denotes a second carriage, which has two legs 21 at its lower part. Each leg 21 is provided with mounting holes facing each other, and the lower part of the first carriage 15 is held between the two legs 21. By passing the lower guide shaft 12 through the mounting hole in such a manner that it can move together with the first carriage 15 and rotate around the lower guide shaft 12.

A rotation hole 22 parallel to the upper guide shaft 11 etc. is provided on the back side of the second carriage 20, and a recess 23 and a mounting hole are provided on the front side, that is, the side facing the platen 2. Grooves 24 and 25 are formed, and the heat sink T is inserted into the recess 23, and the protrusion 9 is inserted into the recess 23.
, 10 are fitted into the mounting grooves 24, 25, respectively, so that the thermal head 5 is held by the second carriage 20 so as to face the platen 2.

Here, the projection 10 and the mounting groove 25 are fitted together using the elasticity of the portion where the mounting groove 25 is formed, and the heat sink 177 is detachable from the second carriage 20. It becomes.

Further, the flexible cable 21 connected to the thermal head 151 is led to the back surface of the first carriage 15 via the lower part thereof, and is locked to the protrusion 18 and fixed by a cable clamp 19.

Reference numeral 26 denotes a spring as a biasing means passed between the front side of the first carriage 15 and the back side of the second carriage 20.
0 is always pressed in the direction of the platen 2, so that the thermal head 5 comes into close contact with the elastic body 3 of the platen 2.

A rotation pin 27 corresponds to the rotation hole 22 of the second carriage 20, and the tip thereof is conical (see FIG. 12).

This rotation pin 27 is press-fitted and fixed from one side of the frame 1 toward the rotation hole 22, but when the thermal head 5 is pressed against the elastic body 3 of the platen 2, the center part is pressed into the rotation hole 22. The position is set to be a certain amount closer to the first carriage 15 than the center of the hole 22.

A feed roller 28 is arranged below the platen 2, and its central shaft 29 is rotatably supported on both sides of the frame 1, and is connected to a line feed motor, also not shown, via a reduction gear train, not shown. ing.

30 is a paper chute arranged along the outer periphery of the feed roller 28, and this paper chute 30 is equipped with a leaf spring 3.
1 is fixed by welding or the like, and a print medium 32 supplied from outside the frame 1 is pressed against the feed roller 28 by a plate spring 31.

Next, the operation of the above-described configuration will be explained.

Now, as shown in Fig. 12 (4), the first carriage 15
When the thermal head 5 and the second carriage 20 are at the normal printing stop position a, the thermal head 5 is in close contact with the elastic body 3 of the platen 2.

Therefore, when setting the print medium 32, the drive shaft 13 is first rotated in a predetermined direction by a space motor (not shown), and then guided by the upper guide shaft 11 and the lower guide shaft 12 to the left, that is, to the home position b.
As the second carriage 20 is moved to the side, the rotation hole 22 provided in the second carriage 20 gradually fits into the rotation pin 27 fixed to the frame 1.

As the two are fitted together, the second carriage 20 rotates around the lower guide shaft 12 so as to separate the thermal head 5 from the elastic body 3 of the platen 2, and the thermal head 5 returns to the home position b. When the rotation of the drive shaft 15 is reached, the rotation of the drive shaft 15 is stopped, and the thermal head 5 is stopped together with the first carriage 15 and the second carriage 20.

At this time, the tip of the rotation pin 27 is completely fitted into the rotation hole 22 as shown in FIG.

In this state, the printing medium 32 shown in FIG. 9 is inserted between the feed roller 28 and the paper chute 30, and pushed until the leading end of the printing medium 32 is pressed against the feed roller 28 by the leaf spring 31.

Thereafter, by driving a line feed motor (not shown) to rotate the feed roller 28 together with its center shaft 29 in a predetermined direction, the print medium 32 is loaded between the platen 2 and the thermal head 5, and a fixed amount of the print medium 32 is loaded between the platen 2 and the thermal head 5. Once loaded, the rotation of the feed roller 28 is stopped.

After completing the setting of the print medium 32 in this way,
When printing, the space motor rotates the drive shaft 13 in the opposite direction.

As a result, the thermal head 5 moves to the right in FIG. 14 together with the first carriage 15 and the second carriage 20, and as a result, the fitting between the rotation hole 22 and the rotation pin 27 is gradually released. Accordingly, the second carriage 20 is rotated by the spring 26 about the lower guide shaft 12 in the opposite direction.

When the position a is reached, the rotation hole 22 is completely removed from the rotation bin 27, and the thermal head 5 is brought into close contact with the elastic body 3 of the platen 2 via the printing medium 32, as shown in FIG. After that, the thermal head 5 moves further to the right together with the first carriage 15 and the second carriage 20, and after passing through the acceleration range shown in FIG. The printing medium 3
Print on 2.

When one line of printing is completed, the feed roller 28 is rotated again by the line feed motor, which causes the υ printing medium 3 to be rotated again.
2 line feed is performed, and this line feed is performed while the thermal head 5 is in close contact with the elastic body 3 of the platen 2 via the print medium 32.

The conventional serial thermal printer has been described above, but it has the following problems.

[Problem that the invention seeks to solve]

Figure 13 is a side view showing problems when setting print media.
As shown in this figure, when the thermal head 15bgc is separated from the platen 2 at the home position b and the printing medium 32 is coded, the platen 2 is in a state where it can freely rotate, so the printing is sent from below. When the leading edge of the medium 32 gets caught on the platen 2, the platen 2 rotates, and as a result, the gap between the platen 2 and the thermal head 5 narrows as shown in section A, causing the print medium 32 to become skewed. However, in some cases, there was a problem that loading could not be achieved.

In addition, when loading is performed with the platen 2 rotated, the thermal head 5 moves from the home position b for printing, and the front tab elastic body 3 of the platen 2 moves.
There is also the problem that when the printing medium 32 is pressed against the thermal head 5, the friction between the elastic body 3 and the printing medium 32 prevents the printing medium 2 from rotating back to its original position, making it impossible to obtain good adhesion between the thermal head 5 and the elastic body 3. there were.

Furthermore, FIGS. 14(A) and 14(B) are diagrams showing problems when moving the carriage, and as described above, the first carriage 15
The holes 16 provided in the first carriage 15 are vertically elongated, and this is done to absorb errors during carriage manufacture and assembly, and to allow smooth movement of the first carriage 15. - causes the first carriage 15 to tend to tilt as shown in ) in FIG. There was also the problem that it caused mobility problems.

The present invention was made in order to solve these problems, and an object of the present invention is to realize a serial thermal printer that can prevent rotation of the platen when setting print media and can perform good carriage movement. It is something to do.

[Failure to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a protrusion on one side of the platen that protrudes in a direction facing the thermal head, and an arm corresponding to the protrusion is formed on one side of the second carriage. In addition, two legs formed at the bottom of the second carriage are connected by a lip.

[For production]

According to the present invention having the above-described configuration, when the thermal head is returned to the home position together with the first carriage and the second carriage when setting the print medium, the arm part provided on the second carriage rides on the protrusion, and the arm part rides on the protrusion. Since the second carriage rotates as the firming part receives a pressing force from the protrusion, the thermal head is separated from the platen by a certain amount.

At this time, the platen is held unrotatable by the pressure of the arm portion and the protrusion.

Therefore, according to this, the printing medium can be stably loaded between the platen and the thermal head. - Not only does this prevent the thermal head from being unable to print, but also provides good adhesion between the thermal head and the platen when the thermal head is moved toward the printing area.

Furthermore, since the two legs of the second carriage are connected by a rib, even if the first carriage is tilted to some extent, the legs do not spread out as in the conventional case, and good carriage movement is possible. Become.

〔Example〕

An embodiment will be described below with reference to the drawings.

Fig. 1 is a plan view of essential parts showing an embodiment of a serial thermal printer according to the present invention, Fig. 2 is a side view corresponding to Fig. 1, Fig. 3 is a perspective view of the platen, and Fig. 4 is a diagram showing the embodiment. 5 is a perspective view of the carriage and thermal head in FIG. 4, FIG. 6 is an explanatory diagram showing an example of the elements of the thermal head, FIG. 7 is a side sectional view of the main part when printing media is set, FIG. 8 is a view taken along arrow E in FIG.

In the figure, reference numeral 33 denotes a frame of the printer. This frame 33 is made of elastic resin, and as shown in FIG. 35, and a support hole 36 corresponding to the other side of the platen is provided on the other side.

3T is a platen, and the front side is formed of a flat elastic body 38 such as heat-resistant rubber, which is the same as before, but on one side of this platen 37, there is a platen facing in the direction opposite to the thermal head described later. The protrusion 39 that protrudes from the
A support shaft 42 having seven flange 40.41 protruding in the opposite direction is formed, and a substantially columnar support shaft 43 is formed on the other side, and when this support shaft 43 is fitted into the support hole 36, By inserting the support shaft 42 through the insertion hole 34 and fitting it into the support hole 35, the platen 37 is supported so as to be rotatable at a certain angle so that it can come into surface contact with the thermal head described later on the surface of the elastic body 38. There is.

Note that the flanges 40, 41 prevent the platen 31 from moving in the left-right direction.

44 is a thermal head, and this thermal head 44 is connected to a flexible cable 4 as shown in FIGS. 5 and 6.
5 is connected so that driving energy is transmitted from a control means (not shown).

Reference numeral 46 denotes a heat sink with a roughly shaped cross-sectional shape, and a fixing protrusion 48 is formed in each of the two mounting grooves 47 formed by the above-mentioned shape, and the front side serves as a positioning reference. A protrusion 49 is formed, and the thermal head 44 is adhesively fixed to the heat sink 46 with one side aligned with the protrusion 49.

50 is an upper guide shaft, 51 is a lower guide shaft, and both ends of the shafts 50 and 51 are supported on both sides of the frame 33 so as to be parallel to each other.

Reference numeral 52 denotes a drive shaft located between the upper guide shaft 50 and the lower guide shaft 51, which has a spiral groove 53 on its outer peripheral surface, and this drive shaft 52 is supported on both sides of the frame 33. The trap is rotated by a space motor (not shown).

Reference numeral 54 denotes a first carriage made of elastic resin, and as shown in FIG. An engagement groove 55 is provided in the lower portion of the first carriage 54 passing through the cover.

Reference numeral 56 denotes a feed pin attached to the first carriage 54, and the tip of the feed pin 56 protrudes into the hole through which the drive shaft 52 passes and engages with the groove 53 of the drive shaft 52. When the shaft 52 rotates, the first gear ridge 54 can move on the drive shaft 52 due to the action of the feed pin 56 and the groove 53.

57 is the first carriage! The protrusion provided on the back of i4,
58 is a cable clamp.

A second carriage 59 is made of elastic resin like the first carriage 54, and has two legs 61 integrally connected to each other by a cylindrical lip 60 at the bottom. The lip 6 is arranged so that the portion 61 holds the lower part of the first carriage 54.
By engaging the o in the engagement groove 55 of the first carriage 54, there is almost no rattling in the left and right directions, and the first carriage 54 can be moved in the vertical direction. 61 through the lower guide shaft 51 in series, the platen 3 is integrated with the first carriage 54.
The platen 37 can reciprocate along the front surface of the platen 37 and rotate about the lower guide shaft 51 in a direction facing the front surface of the platen 37 .

Further, a notch 62 is formed in the center of the second carriage 59 and corresponds to the part between the mounting grooves 48 of the heat sink 46 and the fixing protrusion 49, and is fixed to the part from above the notch 62. By fitting the projection 49 into the notch 62 using elasticity, the thermal head 44 is fixedly held so as to face the elastic body 3'8 of the platen 37.

Here, the fixing protrusion 49 and the notch 62 are fitted together using the elasticity of the second carriage 59, but with this structure, the heat sink is 46, and 1st. Since the width of the second carriages 54 and 59 can be made small, it is possible to design them into an lJS type.

Further, as shown in FIG. 6, by taking advantage of the fact that the width of the heat sink 46 is wide, it is possible to mount thermal heads 44 of, for example, 16 elements and 26 elements on the heat sink 46 of the same size, and the center of the heat sink 46 and the thermal head 44 can be mounted. By keeping the dimension t with respect to the element section 44 constant, the first carriage 54, second carriage 59, and heat sink 46 can be used in common for two or more types of printers without having to correct the home position or printing position. It also becomes possible to use it as a component.

The flexible cable 45 connected to the thermal head 44 is guided to the rear side of the first carriage 54 via the lower part thereof, is engaged with a protrusion 57, and is fixed by a cable clamp 58.

63 is the platen 37 from one side of the second carriage 59.
An arm portion is formed to protrude toward the protrusion 39 formed on the support shaft 42 of the arm portion 63. When the thermal head 44 comes into close contact with the elastic body 38 of the platen 37, the front surface of the arm portion 63 is formed to protrude toward the protrusion 39 formed on the support shaft 42 of the platen 37. The distal end surface is set to be close to the elastic body 38 side, and furthermore, the protruding length of this arm portion 63 is set to be close to the second carriage 59 together with the thermal head 44.
The length is such that the front portion rides on the tip surface of the protrusion 39 when the protrusion 39 is located at the home position b.

Reference numeral 64 denotes a spring as a biasing means passed between the front side of the first carriage 54 and the back side of the second carriage 59.
is constantly pressed in the direction of the platen 37 with an appropriate force, thereby causing the thermal head 44 to press against the elastic body 38 of the platen 37.
It is designed to be in close contact with the

Reference numeral 65 denotes a feed roller disposed below the platen 37, whose central shaft 66 is rotatably supported on both sides of the frame 33, and is connected to a line feed motor, also not shown, via a reduction gear train, not shown. There is.

A vapor chute 67 is arranged along the outer periphery of the feed roller 65 and is fixed to the frame 33.

A plate spring 68 is fixed to the lower surface of the vapor chute 67 in a pre-tensioned state by welding or the like, and as shown in FIGS. A shaft γ1 of a pressure roller 70 is rotatably held in a bearing portion 69 formed by bending a portion, and the pressure roller 70 is pressed against a feed roller 65 by a leaf spring 68 via this shaft 71. .

Note that the pressure roller 70 is disposed diagonally below the feed roller 65 at a position of about 45 degrees.

Next, the operation of the above-described configuration will be explained.

First, as shown in FIG. 1(4), when the thermal head 44 is in the normal printing position a together with the first carriage 54 and the second carriage 59, the thermal head 44 is in close contact with the elastic body 38 of the platen 37. It is in a state.

Therefore, when setting the printing medium 32, first, the drive shaft 52 is rotated in a predetermined direction by a space motor (not shown), and the upper guide shirt 50 and the lower guide shaft 510 guide the print medium 32 to the left (1) home position b.
As the second carriage 59 is moved to the side, the arm portion 63 provided on the second carriage 59 gradually rides up the protrusion 39 provided on the support shaft 42 of the platen 37 and located outside the medium passage range. go.

As the arm portion 63 is pushed by the protrusion 39 as a result of this climbing operation, the second carriage 59 rotates around the lower guide shaft 51 so as to separate the thermal head 44 from the elastic body 38 of the platen 37. death,
When the thermal head 44 reaches the home position b and is detected by a detection means such as a microswitch (not shown), the rotation of the drive shaft 52 is stopped, and the thermal head 44 is moved to the home position b along with the first carriage 54 and the second carriage 59. Stop at home position b.

At this time, the arm portion 63 completely rides on the protrusion 39 as shown in FIG. 1(B), thereby causing the thermal head 44 to
is spaced a certain amount from the elastic body 38 to provide a gap (platen gap) G shown in FIG. 7, and the platen 37 is held unrotatable by the mutual pressure of the protrusion 39 and the arm 63.

In this state, when the print medium 32 shown in FIG. 4 is inserted between the feed roller 65 and the paper chute 670 and pushed in, the leading edge of the print medium 32 will easily meet the feed roller 65 along the R of the paper chute 67. pressure roller 7
0 reaches the pressure contact part.

Thereafter, by driving a line feed motor (not shown) to rotate the foot roller 65 together with its center shaft 66 in a predetermined direction, the print medium 32 is loaded between the platen 37 and the thermal head 44, and a fixed amount of the print medium 32 is loaded between the platen 37 and the thermal head 44. After loading, the rotation of the feed roller 65 is stopped.

After completing the setting of the print medium 32 in this way,
When printing is performed, the drive shaft 52 is rotated in the opposite direction by the space motor.

As a result, the thermal head 44 moves integrally with the first carriage 54 and the second carriage 59 to the right in FIG. The second carriage 59 has a spring 6
4 rotates about the lower guide shaft 51 in the opposite direction.

When the arm part 63 reaches the position a, the arm part 63 is completely separated from the protrusion part 39, and as shown in FIG. Thereafter, the thermal head 44 moves further to the right together with the first carriage 54 and the second carriage 59, and after passing through the acceleration range shown in FIG. Printing is performed on the print medium 32 according to the drive energy supplied through the cartridge, but even if the first carriage 54 is tilted, the two legs 61 of the second carriage 59 are united by the ribs 60. I won't open it because it's there.

When one line of printing is completed, the feed roller 65 is rotated again by the line feed motor, which causes the printing medium 3
2 line feed is performed, but this line feed is performed by the thermal head 44.
This is performed while the printing medium 32 is in close contact with the elastic body 38 of the platen 2.

In the embodiment described above, the thermal head 44 is spaced parallel to the platen 37 by the protrusion 39 and the arm 63, but the protrusion 39 and the arm 63
It is also possible to separate the thermal head 44 and the platen 3T so that they form a V-shape by changing the angle of the surfaces in pressure contact with each other.

〔Effect of the invention〕

As explained above, the present invention provides a protrusion on one side of the platen that protrudes in a direction facing the thermal head,
An arm corresponding to the protrusion is formed on the second carriage, and this arm is placed on the protrusion to rotate the second carriage and separate the thermal head from the platen. Since the printing medium is held unrotatable, the printing medium can be stably loaded between the platen and the thermal head.

Accordingly, this eliminates the problem of the printing medium getting caught in the thermal head and causing the thermal head to rotate as in the past, and it is possible to prevent the printing medium from skewing or being unable to load it due to this, and to prevent printing. This also has the effect of providing good adhesion between the thermal head and the platen.

In addition, since the two legs of the second carriage are fixed together with a lip, even if the first carriage is tilted during movement, the legs do not spread out like in the conventional case, and a good carriage is achieved. It also has the effect of making it possible to move.

[Brief explanation of the drawing]

Fig. 1 is a plan view of essential parts showing an embodiment of a serial thermal printer according to the present invention, Fig. 2 is a side view corresponding to Fig. 1, Fig. 3 is a perspective view of the platen, and Fig. 4 is a diagram showing the embodiment. 5 is a perspective view of the carriage and thermal head in FIG. 4, FIG. 6 is an explanatory diagram showing an example of the elements of the thermal head, FIG. 7 is a side sectional view of the main part when printing media is set, 8 is a view taken in the direction of arrow E in FIG. 7, FIG. 9 is a side sectional view showing a conventional serial thermal printer, FIG. 10 is an enlarged perspective view of the carriage in FIG. 9, and FIG. 12 is an enlarged perspective view of the thermal head in FIG. 9, FIG. 13 is a side/original view showing problems when setting print media in the conventional example, and FIG. 14 is a diagram when the carriage is moving. It is a figure showing a problem. 32... Print medium 37... Platen 38...
Elastic body 39... Projection 44... Thermal head
46...Heat sink 50...Upper guide shaft 51...Lower guide shaft 52...Drive shaft 54...First carriage 59...Second carriage 63...Arm portion 64...Spring Patent Applicant Oki Electric Industry Co., Ltd. Agent Patent Attorney Takashi Kanakura 2nd 57th P Vision A 3 l Fire 4 Ri IJ All 4 Flaws Tsurushu Sensuke 4 Rohemari Tsuji ° Soaked “Warmer” lrehe...／卜°、Ht2
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Claims (1)

[Scope of Claims] 1. A platen whose front part supporting a printing medium is a flat surface and whose both sides are rotatably supported; a thermal head that is fixedly held on the carriage and prints on the print medium; and biasing means that applies biasing force to the carriage so as to press the thermal head against the platen. In the serial thermal printer, a protrusion protruding in a direction facing the thermal head is provided on one side of the platen, an arm portion corresponding to the protrusion is formed on the carriage, and the arm portion is configured to When the carriage moves and rides on the tip surface of the protrusion, the carriage rotates and the thermal head is separated from the platen by a certain amount, and the platen is held unrotatable by mutual pressure contact between the arm part and the protrusion. A serial thermal printer featuring