JPH07137315A - Thermal line printer - Google Patents

Abstract

PURPOSE:To simplify and miniaturize a structure and to enable the use of plain paper by providing a means applying the printing data corresponding to one row in the lateral direction of paper to an ink ribbon by a thermal line head to perform printing. CONSTITUTION:Paper 20 is inserted in the paper insertion port 13 of a printer main body case 11 along with the ink ribbon 33 drawn out of the ink ribbon outlet 34 of an ink ribbon cassette 30. Next, a platen roller is slightly rotated and driven in a forward direction to bring the paper 20 and the ink ribbon 33 to a close contact state to bond the leading end part of the ink ribbon 33 and the paper by an adhesive layer. When the platen roller is rotationally driven at a predetermined speed while printing data is applied to the thermal line head 15 in this state, the ink layer of the ink ribbon 33 to which printing data is applied is selectively melted to be transferred to the paper 20. The paper 20 and the ink ribbon 33 after the completion of printing are discharged out of a paper and ink ribbon outlet 17.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermal line printer.

[0002]

2. Description of the Related Art A thermal line printer for simultaneously providing a line of printing information requires a thermal line head having a length corresponding to the width of a sheet, but it is not necessary to move the head mechanically. There is. However, in the conventional thermal line printer, when used in the thermal transfer system, it is necessary to wind both ends of the ink ribbon into the ink ribbon cassettes on the supply side and the winding side, respectively, and feed the ink ribbon in synchronization with the feeding of the paper. Therefore, there is a problem in that the feeding mechanism of the ink ribbon becomes complicated and the entire apparatus becomes large. Further, if the feeding speed of the ink ribbon and the feeding speed of the paper are not synchronized, the print quality is deteriorated. Furthermore, it is necessary to prepare special paper such as thermal paper and peel-off paper, and plain paper cannot be used. In addition, when using cut paper such as thermal paper or peel-off paper without using an ink ribbon in a conventional thermal line printer, it is necessary to prepare a mechanism such as a separate roller or separation rubber when performing automatic paper feeding. However, there is a problem that the device becomes larger.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermal line printer using a thermal line head and an ink ribbon, which has a simple structure, is small in size, and can use plain paper.

[0004]

SUMMARY OF THE INVENTION The present invention, as a result of re-examination of the conventional common general knowledge that an ink ribbon cassette is indispensable on the supply side and the winding side, respectively
It was concluded that the mechanism can be simplified and the entire device can be miniaturized if the used parts are sequentially discarded.

The thermal line printer of the present invention includes a holding portion for a one-sided ink ribbon cassette wound with an ink ribbon; an insertion port for a sheet to be printed; a sheet inserted through this insertion port; and a one-sided ink ribbon cassette. A means for superposing the ink ribbon pulled out from the set; a platen roller for sending the paper and the ink ribbon in a superposed state, and a thermal line head for the ink ribbon sent by the platen roller and superposed on the paper. And a means for printing by simultaneously giving print information for one line in the width direction of the paper.

The ink ribbon may be coated with an adhesive for adhering the paper. It is preferable that this adhesive has the strongest adhesive force at the central portion in the width direction of the ink ribbon and becomes weaker toward the peripheral portion.

The means for superposing the paper and the ink ribbon may be provided separately from the platen roller and the thermal line head, but both can be used in common. It is preferable that the platen roller is provided with a winding prevention claw for preventing the ink ribbon cut by the cutting means from winding around the platen roller.

The present invention is also characterized by a specific element arrangement for realizing a miniaturized thermal line printer based on the above concept. That is, according to another aspect of the present invention, a casing having a substantially rectangular parallelepiped shape; a platen roller rotatably arranged along an inner side of one ridge line at an upper portion of the casing; A motor for rotating and driving the platen roller and its drive gear train are provided; a thermal line head elastically contacting the platen roller from below; and a thermal line head elastically formed on the upper wall and side wall of the casing along the platen roller. Further, it is characterized in that it has an insertion port and a discharge port for printing paper.

In the thermal line printer of the present invention, the platen roller also has the functions of feeding paper, adhering the paper to the head, feeding the paper, and ejecting the paper. The thermal line head is swingably supported about a swing shaft and has at least 2
Preferably, two spaced leaf springs bias the platen roller.

At the bottom of the casing, a printer control board can be arranged avoiding the leaf spring and the thermal line head.

Further, in order to uniformly press the thermal line head against the platen roller and eliminate uneven printing, the swing axis of the thermal line head parallel to the platen roller is urged toward the platen roller side. It is desirable to movably support it in a direction against the force of the biasing means.

Further, when a plurality of cut sheets such as thermal paper and peel-off paper are superposed and supplied without using an ink ribbon, a special separating member has a separating action for feeding only the sheet on the platen roller side. Can be given as follows without using. That is, between the platen roller and the thermal line head, the first,
When the second sheet is supplied, a force F1 is applied to the first sheet that contacts the platen roller in the feeding direction by the platen roller, and a feeding direction is applied to the second sheet by friction with the first sheet. Is F2, a force acting between the paper and the head in the direction opposite to the feed direction is F3S, a force acting between the second paper and the casing in the direction opposite to the feed direction is FG, and The wedge effect force for preventing the paper from entering the gap between the first paper and the thermal line head is F3.
K, F3S + F3K + FG = F3 ′, F3 ′ is a resistance force in the direction opposite to the feed direction that acts on the second sheet, and if F1> F3 ′> F2 is satisfied, no special separating member is required. Paper can be sorted.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a diagram showing the basic configuration of a thermal line printer according to the present invention. A holding portion 12 for the ink ribbon cassette 30 is formed on the top of the printer body case 11. In front of the holding portion 12, the paper insertion slot 1
3 is opened, and inside the printer body case 11,
A platen roller 14 and a thermal line head 15 are arranged above and below the sheet conveyance path through the sheet insertion port 13. Thermal line head 15
As is well known, has a column-shaped thermal head aligned in the axial direction of the platen roller 14 (direction perpendicular to the paper surface), and can print one line of character information at the same time. This thermal line head 15 uses a compression spring 16
It is pressed against the platen roller 14 side.

A paper and ink ribbon outlet 17 is opened in the printer body case 11 at the rear side of the conveying path by the platen roller 14 and the thermal line head 15, and a cutter 18 is provided at the paper and ink ribbon outlet 17. Is provided. The cutter 18 may be a fixed type that lifts and cuts the ink ribbon,
As shown by the arrow, the paper and ink ribbon outlet 17 may be movable in the opening / closing direction, and the ink ribbon (and the paper) may be cut when the outlet 17 is moved in the closing direction. On the contrary, the continuous ink ribbon may be directly stored in the discharge box without providing the cutter 18.

The printer body case 11 is located between the platen roller 14 and the outlet 17, and the cutter 1
A winding prevention claw 19 that prevents the ink ribbon cut at 8 from winding around the platen roller 14 is fixed. The winding prevention claw 19 can be positioned by adhering the ink ribbon that is lifted and cut to the cutter 18 side.

The ink ribbon cassette 30 is a cassette case 31 in which an ink ribbon 33 wound around a winding core 32 is rotatably housed. The ink ribbon 33 pulled out from the winding core 32 is discharged from an ink ribbon outlet 34. It is guided into the paper insertion slot 13. As shown in FIG. 2, one end of a leaf spring 35 for pressing the ink ribbon 33 against the winding core 32 is fixed in the cassette case 31.
5 prevents loosening of the ink ribbon 33, and a predetermined tension is applied to pulling out the ink ribbon 33. The leaf spring 35 is preferably provided in the center portion of the ink ribbon 33 in the width direction in order to prevent skew of the ink ribbon 33 (inclination of the ink ribbon). Further, even if the bearing portion of the winding core 32 is provided with means for giving resistance to the rotation of the winding core 32, a predetermined tension can be given to the ink ribbon 33. Furthermore, on the shaft of the winding core 32,
It is possible to positively provide a torsion spring to give tension to the ink ribbon 33.

The ink ribbon 33, as shown in FIG.
An ink layer 33b and an adhesive layer 33c are sequentially laminated on a base material 33a. The adhesive layer 33c has the strongest adhesive force in the central portion in the width direction, and as it goes to the peripheral portion,
It is preferable that the adhesive strength is weak. By increasing the adhesive force at the center, the paper and the ink ribbon 3
3 and 3 can be prevented from tilting after bonding. Of course,
The adhesive force of the adhesive layer 33c here is such that the ink ribbon 33 can be easily separated from the paper after printing. Instead of the adhesive, the direct frictional resistance between the ink layer and the paper, the suction action by static electricity or air, or the viscosity generated by heating and slightly melting the ink layer 33b of the ink ribbon 33 can be used.

In this apparatus having the above-described structure, the paper 20 to be printed is inserted from the paper insertion opening 13 of the printer body case 11 together with the ink ribbon 33 pulled out from the ink ribbon outlet 34 of the ink ribbon cassette 30, and the platen roller 14 is slightly moved. The paper 20 and the ink ribbon 33 are brought into close contact with each other by being rotationally driven in the positive direction. Then, the leading end of the ink ribbon 33 and the paper 20 are bonded by the adhesive layer 33c. In this state, when the platen roller 14 is rotationally driven at a predetermined speed while giving the print information to the thermal line head 15, the ink ribbon 3 to which the print information is given.
The third ink layer 33b is selectively melted and transferred to the paper 20. That is, in this embodiment, the operation of superposing the paper 20 and the ink ribbon 33 and the thermal transfer printing simultaneously proceed.

The printed paper 20 and the ink ribbon 3
3 is ejected from the paper and ink ribbon outlet 17.
The platen roller 14 rotates by the number of rotations corresponding to the size of the sheet 20 and stops. Therefore, the paper 20 can be separated from the ink ribbon 33 and taken out. on the other hand,
The ink ribbon 33 is cut by the cutter 18,
The tip of the cut ink ribbon 33 is prevented from being wound around the platen roller 14 by the winding prevention claw 19. At this time, the adhesive layer 33c of the ink ribbon 33 can bond the ink ribbon to the anti-wrapping claw 19, so that the cutting position of the ink ribbon 33 is the reference position when the ink ribbon 33 is initially set. be able to. Thereafter, the paper 20 can be continuously printed by sequentially inserting the paper 20 from the paper insertion port 13.
In the above description, the control of the thermal line head 15 is not mentioned, but the information such as the paper size is given to the control device of the thermal line head 15.

In order to prevent the skew between the paper 20 and the ink ribbon 33, the platen roller 14 may have the largest diameter in the central portion in the lengthwise direction and may be gradually reduced in diameter toward the peripheral portion. Adhesive layer 33 of ink ribbon 33
Increasing the adhesive force of c toward the center is more effective in combination with the platen roller 14 of this shape. Further, when the sheet 20 is inserted, the platen roller 14 is slightly rotated in the reverse direction and then is rotated in the normal direction to prevent the inclination.

Although the above embodiment is an embodiment in which the operation of superposing the paper 20 and the ink ribbon 33 and the thermal transfer printing are carried out at the same time, the paper 20 is preceded by the thermal transfer printing.
The ink ribbon 33 and the ink ribbon 33 may be superposed.

When the paper 20 is an irregularly shaped paper, the cutter 18 is used to remove the ink ribbon 33 and the paper 2 from each other.
Cut 0 at the same time. As for the irregular-shaped paper, as shown in FIG. 5, the ink ribbon cassette 30 may be removed from the printer body case 11 and the ink ribbon 33 may be pre-bonded to the irregular-shaped paper 20 ′ placed on the flat plate 21. Since this paper to which the ink ribbon 33 is attached in advance is a so-called peel-off paper, it can be directly transferred between the platen roller 14 and the thermal line head 15 for thermal transfer printing.

The cutter 18 is a straight-moving type, but a rotary type cutter may be used, or perforations, breakage openings, etc. may be provided on the ink ribbon 33 at predetermined intervals. Further, the ink ribbon 33 can be cut by heat using a heating element of the line head or a heating wire.

Next, FIG. 4 shows another embodiment of the ink ribbon cassette 30A according to the present invention. This ink ribbon cassette 30A is provided with a mechanism for superposing it on the paper 20 and a cutting mechanism.
A paper insertion port 36 is provided in the paper. Paper insertion slot 3
A roller 37 and a leaf spring 38 that comes into contact with the roller 37 are provided in the insertion path of 6, and the sheet insertion port 36
The paper 20 inserted through the paper passes between the roller 37 and the leaf spring 38 together with the ink ribbon 33, is bonded to the ink ribbon 33 while passing, and is discharged from the discharge port 39. The discharge port 39 is further provided with a cutter 40. The cutter 40 cuts only the ink ribbon 33 or the paper 20 and the ink ribbon 33.

When this ink ribbon cassette 30A is used, the paper 2 is inserted into the paper insertion opening 13 of the printer body case 11.
Before inserting 0, the paper can be processed into a peel-off paper. Therefore, printing can be easily performed by passing the sheet from the sheet insertion port 13 between the platen roller 14 and the thermal line head 15.
In other words, the ink ribbon cassette 30A is a peel-off paper manufacturing apparatus, and by mounting it on the printer body case 11, a very simple thermal line printer can be constructed. In the ink ribbon cassette 30A, the ink ribbon 33 can be cut by the cutter 40 before the printing by the thermal line head 15 or at the same time as the printing. In short, from the ink ribbon 33 to the platen roller 1
The cutting timing may be set in accordance with the sheet conveyance distance to reach 4 (thermal line head 15).

6 to 10 show a more specific embodiment of the thermal line printer according to the present invention. The casing 50 has a substantially rectangular parallelepiped shape having a width larger than a printing paper width (for example, A4), and has an upper wall 50a, both side walls 50b,
It has 50c, a bottom wall 50d, and both end walls 50e, 50f. A pair of ridge lines formed by the upper wall 50a and the side wall 50b and the upper wall 50a and the side wall 50c are present on the upper portion of the casing 50.
The platen roller 14 is rotatably supported along the inner side of the ridge line formed by. A thermal line head 15 is disposed below the platen roller 14 so as to be swingable around a swing shaft 15a. Between the thermal line head 15 and the bottom wall 50d of the casing 50, a thermal line head 15 is provided.
A leaf spring 51 that urges the thermal line head 15 toward the platen roller 14 is provided. This leaf spring 5
The pair 1 is provided in such a manner as to be spaced apart from each other, and is formed in a substantially V shape having fixed leg portions 51a on the bottom wall 50d and elastic leg portions 51b contacting the lower surface of the thermal line head 15, respectively. ing. The elastic leg portion 51b comes into surface contact with the thermal line head 15 to bring it into close contact with the platen roller 14.

A paper insertion opening 52 corresponding to the width of the paper is opened in the upper wall 50a of the casing 50, and a paper discharge opening 53 is opened in the side wall 50b. The sheet insertion port 52 and the sheet ejection port 53 are both formed along the platen roller 14, and the stacked sheet 20 and the ink ribbon 33 are placed inside the sheet insertion port 52, and the platen roller 14 and the thermal line. A lower guide wall 52a for guiding between the heads 15 and an upper guide wall 52b are formed. In addition, in the empty space formed by the platen roller 14 and the thermal line head 15, a sensor 54 for paper detection is provided.
Are arranged. The paper detection sensor 54 can be composed of, for example, a reflection type photo interrupter.

End wall 50e and end wall 50f of casing 50
As shown in FIG. 7, a pair of support frames 55 and 56 for supporting the platen roller 14 and the thermal line head 15 are arranged inside each of the platen rollers 14. The drive motor 57 of is fixed. The output pinion 57a of the drive motor 57 meshes with a driven gear 14b provided on the shaft of the platen roller 14 via a gear train 58, as shown in FIGS. The platen roller 14 is rotationally driven by a drive system including the drive motor 57 and the gear train 58,
The superposed paper 20 and ink ribbon 33 can be drawn between the platen roller 14 and the thermal line head 15 and sent at a predetermined speed to be ejected from the paper ejection port 53.

12 and 13 show how the swing shaft 15a of the thermal line head 15 is supported. The support frames 55 and 56 are provided with elongated holes 55a and 56a in a substantially vertical direction.
Is formed, and the swing shaft 15a is fitted in the elongated holes 55a and 56a so as to be rotatable and movable.
When the swing shaft 15a is rigidly supported so as to be rotatable only, four points A, B, C, D on the head 15 shown in FIG.
Is not located in one plane, the vicinity of the point C or the point D is separated from the platen roller 14 and uneven printing occurs. On the other hand, when the swing shaft 15a is movably supported as described above, the head 15 is moved by the leaf spring 51.
Is pressed against the platen roller 14, and the plane of the head 15 is always determined by the three points A, C, D or B, C, D, so that such printing unevenness does not occur.

A control board 60 of the printer is located on the bottom wall 50d of the casing 50, avoiding the leaf spring 51 and the thermal line head 15. That is, the plane shape of the control board 60 secures the maximum effective area by cutting out the portion of the leaf spring 51. FIG. 11 is a plan view of the substrate 60. In addition, the IC on the control board 60
The size and position of the electronic components 61 such as are determined so as not to interfere with the thermal line head 15 even when the thermal line head 15 is pushed down against the force of the leaf spring 51 as shown in FIG. There is. The casing 50
On the upper surface of the upper wall 50a, as shown in FIG.
A space for installing (attaching / detaching) the ink ribbon cassette 30 is secured on the side portion of 2.

A battery chamber 63 is formed on the side wall 50c side of the casing 50. This battery chamber 63 is at a position different from that of the drive motor 57 (FIG. 7), and the drive motor 5
When viewed from the axial direction of 7, the batteries 64 and the drive motor 57, which are housed in the battery chamber 63 in two upper and lower stages, are provided in a positional relationship where they overlap each other (see FIGS. 8 and 10).

The platen roller 14, the thermal head 15, the drive motor 57, the control board 60, and the electronic component 6 described above.
By arranging 1 and the battery chamber 63 (battery 64), the casing 50 can be made smaller.

The thermal line printer having the above structure is
Just like the printer whose basic principle is described with reference to FIGS. 1 to 3, the superposed paper 20 and the ink ribbon 33 are inserted from the paper insertion opening 52, and are fed by the rotational driving force of the platen roller 14, and this feeding is performed. By supplying print information to the thermal line head 15 in synchronization, the paper 2
Printing for 0 can be performed. When the thermal line head 15 is pushed down against the plate spring 51,
As described above, the platen roller 14 and the thermal line head 15 can be separated from the platen roller 14.
Maintenance around can be easily performed.

FIG. 14 shows a special treatment when cut paper 20 such as thermal paper or peel-off paper is fed between the platen roller 14 and the thermal line head 15 in a stacked manner when the ink ribbon is not used. It is a figure which analyzes the conditions for obtaining the loosening action which gives sending only to the sheet 20 of the platen roller 14 side, without using a member.

Now, when the overlapped first and second papers 20 are supplied between the platen roller 14 and the thermal line head 15, the platen roller is contacted with the first paper 20 contacting the platen roller 14. The force in the feed direction given by 14 is F1, and the force in the feed direction given to the second paper 20 by the frictional force of the first paper 20 is F2,
The force acting between the paper 20 and the head in the direction opposite to the feed direction is F3S, and the force acting between the second paper 20 and the casing in the direction opposite to the feed direction is FG, the second paper 2
The wedge effect force for preventing 0 from entering the gap between the first paper 20 and the thermal line head 15 is F3K, F3S + F3K + FG = F3 ′, and F3 ′ is the drag force acting on the second paper in the opposite direction. If F1> F3 '> F2 ... F3K>F2> F3S + FG ... is satisfied, the sheet 20 can be sorted without requiring a special sorting member. it can. The conditional expression of is a condition for surely separating the two sheets of paper, and the condition of is the second
This is a condition for surely conveying the paper of (1) to a position that satisfies the formula. In consideration of the properties of the paper 20 and the thermal line head 15, the material, hardness, diameter, etc. of the platen roller 14 may be determined so as to satisfy the above conditions. Also, even if there are third, fourth, ... Papers after the second paper,
Since the second sheet is stopped under the condition, the conveying force is not transmitted to the second and subsequent sheets.

[0036]

According to the present invention, a thermal line printer having a very simple structure and a small size can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a thermal line printer according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the ink ribbon cassette of FIG.

FIG. 3 is a cross-sectional view showing an example of an ink ribbon used in the present invention.

FIG. 4 is a sectional view showing another embodiment of the ink ribbon cassette according to the present invention.

FIG. 5 is a diagram showing another usage pattern of the ink ribbon cassette of the present invention.

FIG. 6 is a partial cross-sectional perspective view showing another embodiment of the thermal line printer according to the present invention.

FIG. 7 is a plan view of FIG.

FIG. 8 is a gear train showing the drive system of FIG.

9 is a sectional view taken along the line IX-IX in FIG.

10 is a cross-sectional view showing a state in which the thermal line head in FIG. 9 is pushed down.

FIG. 11 is a plan view of a substrate.

FIG. 12 is a perspective view showing a support mode of a swing shaft of the thermal line head.

FIG. 13 is a side view of the same.

FIG. 14 is a diagram showing a sheet separating function by a platen roller and a thermal line head.

[Explanation of symbols]

 11 Printer Main Body Case 12 Ink Ribbon Cassette Holding Section 13 Paper Insert Port 14 Platen Roller 15 Thermal Line Head 15a Swing Shaft 18 Cutter 19 Winding Prevention Claw 20 Paper 20 'Irregular Paper 30 30A Ink Ribbon Cassette 31 Cassette Case 32 Core Core 33 Ink Ribbon 33a Base material 33b Ink layer 33c Adhesive layer 35 Leaf spring 36 Paper 20 insertion port 37 Roller 38 Leaf spring 39 Discharge port 40 Cutter 50 Casing 51 Leaf spring 52 Paper 20 insertion port 53 Paper 20 discharge port 55 56 Support frame 57 Drive motor 58 gear train 60 control board 61 electronic component 63 battery chamber 64 battery

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location B41J 17/30 BA 25/312 25/316 B41J 25/28 H (72) Inventor Kiyoshi Negishi Tokyo 2-36-9 Maenocho, Itabashi-ku, Tokyo Within Asahi Gaku Kogyo Co., Ltd. (72) Inventor Katsumi Kawamura 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Kogaku Co., Ltd. (72) Inventor Katsuyoshi Suzuki Asahi Kogaku Kogyo Co., Ltd. 2-36 Maenocho, Itabashi-ku, Tokyo (72) Inventor Toshinasa Yamanaka 2-39-9 Maeno-cho Maemachi, Itabashi-ku, Tokyo Asahi Kogaku Kogyo Co., Ltd. 2-36 Maeno-cho, Itabashi-ku, Tokyo Asahi Kogaku Kogyo Co., Ltd. (72) Inventor Mikio Horie 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Kogaku Kogyo Co., Ltd.

Claims (11)

[Claims] 1. A holding portion of a one-sided ink ribbon cassette around which an ink ribbon is wound; an insertion port for paper to be printed;
A means for superposing the paper inserted through the insertion port and the ink ribbon pulled out from the single-sided ink ribbon cassette; a platen roller for feeding the paper and the ink ribbon in a superposed state; A thermal line head that simultaneously applies printing information for one line in the width direction of the paper to the ink ribbon that is overlapped with the paper, and prints. 2. The thermal line printer according to claim 1, further comprising cutting means for cutting the ink ribbon on the downstream side of the platen roller. 3. The thermal line printer according to claim 1, wherein the ink ribbon is coated with an adhesive for adhering paper. 4. The thermal line printer according to claim 3, wherein the adhesive has the strongest adhesive force at the central portion in the width direction of the ink ribbon and becomes weaker toward the peripheral portion. 5. The thermal line printer according to claim 1, wherein the means for superposing the paper and the ink ribbon comprises a platen roller and a thermal line head. 6. The thermal system according to claim 1, wherein the platen roller is provided with a winding prevention claw for preventing the ink ribbon cut by the cutting means from winding around the platen roller. Line printer. 7. A substantially rectangular parallelepiped casing; a platen roller rotatably arranged along the inside of one ridgeline at the upper part of the casing; and a platen roller arranged at one end of the casing. A motor and a drive gear train for rotating the motor; a thermal line head elastically contacting the platen roller from below; a printing line formed on the upper wall and the side wall of the casing along the platen roller. A thermal line printer having an insertion port and an ejection port. 8. The thermal line printer according to claim 7, wherein the thermal line head is swingable about a swing shaft, and is biased toward the platen roller by at least two leaf springs spaced from each other. 9. The thermal line printer according to claim 8, wherein a printer control board is provided at the bottom of the casing, avoiding the leaf spring and the thermal line head. 10. The thermal line head according to claim 8, wherein the swing axis of the thermal line head is provided parallel to the platen roller, and a direction against the force of the biasing means for biasing the thermal line head toward the platen roller. The thermal line printer is movably supported by the. 11. The thermal line printer according to claim 7, wherein the platen roller and the thermal line head perform a peeling function of the sheets when a plurality of sheets of paper that are superposed on each other are supplied between the platen roller and the thermal line head.