JPH061037A - Line thermal printer - Google Patents

Abstract

PURPOSE:To provide a line thermal printer free from maintenance the degree of parallelization of a printing head and a platen can be automatically adjusted without troubling the operator and printing quality is improved. CONSTITUTION:A main body frame 1 having a paper feed path, the platen 10 arranged to the feed path and the printing head 28 opposed to the platen and having a heating pattern provided to the leading end surface 29a pressed to the platen under a specified pressure thereof are provided. A support mechanism 35 supporting the printing head in the vicinity of the central part thereof in the longitudinal direction thereof in such a manner as to rotate the same around the axis crossing the axial line of the platen is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line thermal printer having a thermal transfer type print head, and more particularly to a structure for keeping the print head in an appropriate position with respect to a platen.

[0002]

2. Description of the Related Art A line thermal printer of this type includes a platen arranged on a sheet conveying path and a print head arranged above the platen. The print head extends along the axial direction of the platen. By pressing the front end surface of the print head, which has a heat generation pattern, against the platen, printing is performed on the paper fed on the platen.

By the way, in such a printer, in order to improve the print quality, it is necessary to dispose the print head in parallel with the platen without causing an inclination.
Therefore, in the conventional printer, the head mounting plate that supports the print head is arranged above the platen,
The left and right ends along the longitudinal direction of this head mounting plate,
Each of them is supported by a main body frame of the printer via a support shaft, and one of these support shafts is used as an eccentric shaft.

According to this structure, when the eccentric shaft is rotated, one end side along the longitudinal direction of the print head is moved up and down through the head mounting plate, so that the front end surface of this print head becomes parallel to the platen. Moreover, the posture of the print head can be adjusted.

[0005]

However, in the conventional printer, the mounting posture of the print head is finely adjusted by hand so as to follow the inclination of the platen.
It was necessary to work on the actual product. For this reason, there is a problem that the adjustment work requires a lot of time and that the posture of the print head after the adjustment tends to vary because it is a human work.

Moreover, when the adjustment is completed, even if the parallelism between the front surface of the print head and the platen is maintained normally, the platen and other members expand due to the subsequent changes in the ambient temperature of the printer and the operating conditions. When contracted, the mounting postures of the platen and the print head may individually change. Therefore, the parallelism between the print head and the platen is gradually lost over time,
There was still room for improvement in improving print quality.

The present invention has been made in view of the above circumstances, and the parallelism between the print head and the platen can be automatically adjusted without any manual labor, and the print head can be pressed against the platen. It is an object of the present invention to provide a line thermal printer which can prevent the occurrence of the above and can improve the printing quality and can realize maintenance-free.

Another object of the present invention is to eliminate the mechanism for pressing the print head against the platen from the periphery of the print head, and to open the circumference of the print head widely to simplify the structure. To obtain a line thermal printer that can

Still another object of the present invention is to eliminate the mechanism for separating the print head from the platen from the periphery of the print head, and simplify the structure around the conveying path including the print head. The purpose of the present invention is to obtain a line thermal printer in which the work of taking in and out the ink ribbon for thermal transfer can be performed easily.

[0010]

Therefore, according to a first aspect of the present invention, a main body frame having a sheet conveying path, a platen arranged in the conveying path, and a heat generation pattern on a surface facing the platen are provided. Assuming a line thermal printer having a print head whose facing surface is pressed against the platen with a predetermined pressure, the platen is provided on the main body frame in the vicinity of the central portion along the length direction of the print head. It is characterized in that a support mechanism is provided which is pivotally supported in a direction around an axis intersecting the axis line of.

According to a second aspect of the present invention, the support mechanism includes a rotating arm extending in the axial direction of the platen. One end of the rotating arm opposes the platen and the other end of the rotating arm is opposite to the platen. The platen is extended to a position outside the platen in the axial direction, and a central part along the length direction of the print head is provided at one end of the rotating arm via a pivot shaft extending in a direction intersecting with the axis of the platen. The other end of the rotating arm is rotatably connected to the main body frame while the vicinity thereof is rotatably connected, and the above-mentioned rotation is provided between the other end of the rotating arm and the main body frame. It is characterized in that a spring for pressing the facing surface of the print head against the platen is interposed by urging one end of the arm toward the platen.

Further, according to a third aspect of the present invention, a cam receiving portion is provided at the other end portion of the rotating arm, and the main body frame is brought into contact with the cam receiving portion to move the rotating arm to the spring. A cam member having a cam surface for rotating in the direction away from the platen against the urging force of the plate, and a motor for rotating the cam member to bring the cam surface into contact with the cam receiving portion. Is characterized by.

[0013]

According to the configuration described in claim 1, since the print head is held in a floating state in which the print head can freely rotate with respect to the platen, when the platen is tilted, the print head does not move to the platen. The print head is automatically rotated about the axis so as to follow the inclination, and the parallelism between the print head and the platen is secured.

Therefore, it is possible to obviate the need for manual adjustment work and to prevent the parallelism between the print head and the platen from varying.

According to the second aspect of the present invention, the rotating arm is rotationally biased by the spring located outside the platen and the print head in the axial direction, and the biasing force presses the print head against the platen. Therefore, of the mechanism for pressing the print head, only the rotating arm extending in the axial direction of the platen is arranged around the print head.
Moreover, since the rotational force of the rotating arm is transmitted to the print head via the pivot, the pivot point of the print head and the input point of the force for pressing the print head toward the platen can be made common, and the printing can be performed. It is possible to make the area around the support portion of the head compact.

For this reason, the periphery of the print head can be widely opened, and the press mechanism does not become an obstacle when performing maintenance and inspection of the print head.

In the structure according to the third aspect, when the cam member is rotated by the motor, the cam surface of the cam member comes into contact with the cam receiving portion of the rotating arm, and the cam receiving portion is biased by the spring. Since the pressing arm is pressed against, the rotating arm is forcibly rotated in the direction in which the print head is separated from the platen. These cam members and motors are arranged on the opposite side of the pivot arm from the pivotal fulcrum of the print head, and since they are out of the transport path facing the print head or platen, the print head itself separates from the platen. It is not necessary to add a mechanism for generating a force in the direction.

Therefore, it is possible to widely open around the conveying path including the print head and the platen, and there is no restriction on the arrangement of the print head and the platen, and an ink ribbon for thermal transfer is put in and taken out between them. Also when doing, the work can be easily performed.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings.

1 and 3, reference numeral 1 is a main frame of the line thermal printer. The main body frame 1 includes a support wall 2 which is vertically erected.

A platen support frame 3 is attached to the support wall 2. As shown in FIGS. 4 and 8, the platen support frame 3 includes a pair of left and right side walls 4a and 4b and an upper wall 5 extending between the upper ends of the side walls 4a and 4b. The upper wall 5 constitutes a transport path 6 for feeding a sheet (not shown) on the platen support frame 3, and the transport path 6 extends in the front-rear direction along the support wall 2. Further, the platen support frame 3 is attached to the paper guide wall 7
Is equipped with. The paper guide wall 7 is located on the front side (left side in FIG. 4) of the paper in the paper feeding direction with respect to the upper wall 5, and the side walls 4a, 4
It extends over the upper end portion of b, and between the paper guide wall 7 and the upper wall 5, an elongated opening 8 extending between the side walls 4a and 4b is formed.

A platen roller 10 is rotatably supported on the platen support frame 3. The platen roller 10 is horizontally arranged along a direction orthogonal to the sheet feeding direction, and its rotation shaft 11 is provided between the side walls 4a and 4b. The rotary shaft 11 is driven to rotate by a stepping motor (not shown). The upper part of the platen roller 10 is exposed to the transport path 6 through the opening 8 and is in contact with the lower surface of the sheet fed through the transport path 6.

The side wall 4 of the platen support frame 3
A guide shaft 12 is installed between a and 4b, and the guide shaft 12 is located below the platen roller 10.

A movable frame 13 is provided on the platen support frame 3 so as to be movable in the paper feeding direction.
As shown in FIG. 8, the movable frame 13 includes a pair of left and right side walls 14a and 14b, and a guide wall 15 extending between upper end portions of the side walls 14a and 14b. The side wall 14a,
14 b is located inside the side walls 4 a, 4 b of the platen support frame 3, and the guide wall 15 is located in the opening 8. As shown in FIG. 4, the guide wall 15 is provided flush with the upper wall 5 and the paper guide wall 7. Tongue pieces 16a and 16b extending toward the upper wall 5 are integrally formed at both left and right ends of the guide wall 15. The tongues 16a and 16b are placed on the upper edges of the side walls 4a and 4b, and are located on the left and right sides of the platen roller 10 which are separated from each other in the axial direction.

Of the tongue pieces 16a and 16b, the other tongue piece 16b located on the support wall 2 side is provided with an upward shaft portion 17 so as to project. Fitting holes 18a and 18b are formed in the one tongue piece 16a located on the opposite side of the shaft portion 17 and the upper end surface of the shaft portion 17, respectively. Each of the fitting holes 18a and 18b has a long hole shape extending in a direction orthogonal to the sheet feeding direction, that is, in the left-right direction of the movable frame 13, and the other fitting hole 18b is one fitting hole. It is located above 18a.

Guide holes 20a, 20b are formed in the side walls 14a, 14b of the movable frame 13. The guide holes 20a and 20b are elongated holes extending in the sheet feeding direction, and the guide shaft 12 is inserted into the guide holes 20a and 20b. Therefore, the movable frame 13
Is configured to be moved in the sheet feeding direction with the guide shaft 12 and the upper edges of the side walls 4a and 4b as guides. The side walls 14a and 14b of the movable frame 13 are respectively attached to the side walls 4a and 4b of the platen support frame 3 via the screws 21.
Left and right adjusting mechanisms 22a and 22b using screws for individually moving the side walls 14a and 14b in the sheet feeding direction are fixed between the side walls 14a and 14b and the platen support frame 3. It is provided.

A print head device 25 is arranged above the platen roller 10. As shown in FIG. 9, the print head device 25 includes a head mounting plate 26 made of metal and a print head 28 supported by the head mounting plate 26 via a base 27. The print head 28 of this embodiment is an end surface type line thermal head, and has a head body 29 in the form of an elongated box extending in the axial direction of the platen roller 10. Head body 2
9 has a front end surface 29a facing the platen roller 10, and a heat generating pattern (not shown) is provided on the front end surface 29a.

The head mounting plate 26 has a flat base portion 31 extending in the axial direction of the platen roller 10. An upward joint portion 32 is projectingly provided at a central portion along the length direction of the upper edge of the base portion 31. The joint portion 32 is supported by the support wall 2 of the main body frame 1 via a support mechanism 35. The support mechanism 35 includes a head pressing arm 33 as a rotating arm. The head pressing arm 33 is for moving the print head device 25 up and down with respect to the platen roller 10, and extends along the axial direction of the platen roller 10.

That is, one end 33a of the head pressing arm 33 has the platen roller 10 and the print head device 2.
5, the head pressing arm 33 is led out.
A pivot 34 is provided at the lead-out end of the. As shown in FIGS. 1 and 4, the pivot 34 is horizontally arranged along a direction orthogonal to the axis X ₁ of the platen roller 10, and the pivot 34 connects the joint portion 3 of the head mounting plate 26.
It penetrates 2. Therefore, the head mounting plate 26
Is movable in the axial direction of the pivot shaft 34, and is pivotally supported in the axial direction of the pivot shaft 34 so as to be rotatable.

The other end 33b of the head pressing arm 33 is
Through the through hole 36 opened in the support wall 2 of the main body frame 1, the conveyance path 6 is led out to the opposite side of the support wall 2. A bracket 37 is attached to the support wall 2 in the vicinity of the through hole 36.
The other end 33b of the head pressing arm 33 is pivotally supported by a pivot shaft 38 so as to be vertically rotatable. The pivot shaft 38 is parallel to the pivot shaft 34, and when the head pressing arm 33 rotates about the pivot shaft 38, the print head device 25 is brought into contact with and separated from the platen roller 10 from above.

In this case, the head mounting plate 26 of the print head device 25 has a pair of positioning pins 40.
a and 40b are provided. Positioning pins 40a, 4
0b is located on both left and right sides of the print head 28,
In this embodiment, as shown in FIG. 9, the head mounting plate 2
It is sandwiched between the inner surfaces of the corners at the left and right ends of 6 and a holding piece 41 provided by cutting and raising a part of the corners inward. The lower ends of the positioning pins 40a, 40b are removably fitted into the fitting holes 18a, 18b of the movable frame 13, and the fitting holes 18a, 18b and the positioning pin 4 are inserted.
A gap 42 is formed along the axial direction of the platen roller 10 between 0a and 40b, as shown in FIGS.

Therefore, due to the existence of the gap 42,
The print head device 25 is allowed to rotate about the axis of the pivot 34. Further, even though the print head device 25 can freely rotate as described above by fitting the positioning pins 40a and 40b into the fitting holes 18a and 18b, the print head device 25 can be moved in the front-back direction. Arbitrary movement is blocked.

As shown in FIGS. 3, 6 and 7, the other end portion 33b of the head pressing arm 33 is provided with a pair of plate-shaped bracket portions 44a and 44b. The bracket portions 44a and 44b are arranged at intervals in the axial direction of the pivot shaft 38. These bracket parts 44a, 4
4b extends from around the pivot shaft 38 of the head pressing arm 33 toward the side opposite to the print head device 25,
A locking shaft 45 is installed between the ends.

Above the bracket portions 44a and 44b,
A motor bracket 46 is arranged. The motor bracket 46 is attached to the surface of the support wall 2 opposite to the conveyance path 6, and the motor bracket 46 has a locking piece 47 that extends above the locking shaft 45. A tension coil spring 48 is stretched between the locking piece 47 and the locking shaft 45. The coil spring 48 includes hook portions 48b and 48c at both ends of the coil portion 48a, and the hook portions 48b and 48c are hooked on the locking piece 47 and the locking shaft 45.

Therefore, as shown in FIGS. 1 and 6, the other end 33b of the head pressing arm 33 is pulled upward by the coil spring 48, which causes the head pressing arm 33 to pivot. The tip end surface 29a of the print head 28 is pressed against the peripheral surface of the platen roller 10 by being urged to rotate in a clockwise direction with the fulcrum 38 as a fulcrum.

The bracket portion 44 of the head pressing arm 33
A roller 51 is provided between a and 44b via a roller shaft 50.
Is rotatably supported. The roller shaft 50 is parallel to the pivot shaft 38 and the locking shaft 45, and the roller 51 including the roller shaft 50 includes the pivot shaft 38 and the locking shaft 4.
It is housed in the space between 5 and. The roller 51 causes the head pressing arm 3 to move against the print head device 25.
It is located on the opposite side of the pivot shaft 38, which serves as the fulcrum of rotation of No. 3.

A rotating shaft 53 is supported by the motor bracket 46. The rotary shaft 53 is arranged above the roller shaft 50 in parallel with the roller shaft 50, and a cam member 54 is mounted on the rotary shaft 53. The cam member 54 is rotated integrally with the rotating shaft 53 and is positioned right above the roller 51. And
A cam surface 55 is formed on the peripheral surface of the cam member 54 so as to come into contact with and separate from the peripheral surface of the roller 51. The cam surface 55 is the roller 51
Of the bracket 4 of the head pressing arm 33 against the biasing force of the coil spring 48 when contacted with the peripheral surface of the head pressing arm 33.
4a and 44b are pressed downward, and this pressing causes the head pressing arm 33 to move the print head device 25.
Is rotated in a direction of separating the platen roller 10 from the platen roller 10. From this, in the case of this embodiment,
The roller 51 constitutes a cam receiving portion in contact with the cam surface 55.

The roller shaft 50 of the roller 51 is a motor 57.
Is linked to. The motor 57 is the motor bracket 4
When the roller shaft 50 is rotated by this motor 46, the cam member 54 rotates integrally,
The cam surface 55 contacts the peripheral surface of the roller 51 and presses the bracket portions 44a and 44b of the head pressing arm 33 downward.

In one embodiment of such a construction, the print head device 2 located above the platen roller 10
The head 5 is supported by the head pressing arm 33 so as to be freely rotatable around the axis of the pivot 34. Therefore, as shown by the chain double-dashed line in FIG. 2, when the platen roller 10 is attached to the platen support frame 3 in an inclined state with respect to the horizontal line, the head main body 29 of the print head device 25 presses the head. When it is pressed against the platen roller 10 via the arm 33, first, the head main body 2
One end of 9 contacts one end of the platen roller 10.

Due to this contact, one end of the platen roller 10 apparently pushes up one end of the head main body 29, so that the print head device 25 is naturally rotated about the pivot 34, and the other end of the head main body 29 is reversed. Be lowered.

That is, the print head device 25 automatically changes its posture by following the inclination of the platen roller 10.
The tip surface 29a of the head body 29 and the platen roller 1
The parallelism with 0 is secured. From this, it is possible to prevent a so-called one-sided contact phenomenon in which only one end portion of the head body 29 along the longitudinal direction of the front end surface 29a contacts the platen roller 10 and the other end portion on the opposite side floats up from the platen roller 10.

According to such an embodiment of the present invention, the parallelism between the tip surface 29a of the head main body 29 and the platen roller 10 can be automatically adjusted without any manual labor. Therefore, as in the conventional case, the head body 2
There is no fear that the parallelism between the front end surface 29a of the plate 9 and the platen roller 10 will vary, and the printing quality can be improved.

Moreover, even if the mounting postures of the platen roller 10 and the print head device 25 individually change due to, for example, changes in the ambient temperature of the printer and use conditions, the print head device 25 causes the platen roller 1 to change each time.
The platen roller 10 is rotated with 0 as a reference.
It is automatically adjusted to follow. Therefore, it is not necessary to frequently check the parallelism between the print head device 25 and the platen roller 10, and maintenance-free can be realized.

In the printer having the above structure, the head pressing arm 33 that pivotally supports the print head device 25 is
The platen roller 1 penetrates the support wall 2 of the main body frame 1
0 and the print head device 25 are guided to a position outside the transport path 6 and the head pressing arm 33 is pressed toward the platen roller 10 at the leading end of the head pressing arm 33. A tension coil spring 48 that urges the arm 33 to rotate is arranged.

Therefore, since only the head pressing arm 33 extending in the axial direction of the platen roller 10 is arranged in the vicinity of the print head device 25, the print head device is directly above the print head device 25. As compared with the case where a mechanism such as a cam device for pressing downward 25 and a support shaft thereof is provided, the upper side of the print head device 25 is widely opened.

Moreover, since the rotational force of the head pressing arm 33 is transmitted to the print head device 25 via the pivot 34 which is the pivot point of the print head device 25, the pivot point of the print head device 25 and the print head device 25 are The input point of the force for pressing the device 25 downward is made common, and also in this respect, the supporting portion of the print head device 25 can be formed compactly.

From the above, the periphery of the print head device 25 can be widely opened to simplify its structure.
When performing maintenance and inspection of the print head device 25, the pressing mechanism does not become an obstacle, and workability during maintenance and inspection is improved.

On the other hand, when the ink ribbon for thermal transfer is put in or taken out between the platen roller 10 and the print head device 25, the motor 57 is driven to rotate the cam member 54, and the cam surface 55 is moved to the head pressing arm. 33 roller 51 is brought into contact. Then, since the bracket portions 44a and 44b of the head pressing arm 33 are forcibly pushed down via the roller 51, the head pressing arm 33 resists the urging force of the tension coil spring 48 with the pivot shaft 38 as the fulcrum. It is rotated in the opposite direction. By this rotation, the entire print head device 25 rises and is separated from the platen roller 10. Therefore, the ink ribbon can be taken in and out between the platen roller 10 and the print head device 25.

In this case, one positioning pin 40a supported by the head mounting plate 26 of the print head device 25 is pulled out from the fitting hole 18a of the movable frame 13, while the other positioning pin 40b is fitted. Aperture 1
8b is kept in the fitted state, and rattling when the print head device 25 is raised is prevented.

According to this structure, the cam member 54 and the motor 57 for separating the print head device 25 from the platen roller 10 are opposite to the platen roller 10 and the print head device 25 with the support wall 2 interposed therebetween. Are arranged in the platen roller 10 and the print head device 2.
The periphery of the conveying path 6 facing 5 is wide open.

Therefore, the structure around the conveying path 6 including the print head device 25 and the platen roller 10 can be simplified, and the print head device 25 and the platen roller 1 can be provided.
The degree of freedom in arranging 0 is increased. With that,
Even when the ink ribbon is put in and taken out between the print head device 25 and the platen roller 10, the periphery of the print head device 25 is widely opened, so that there is an advantage that the ink ribbon can be put in and taken out easily.

In the above embodiment, the tension coil spring is used to urge the head pressing arm to rotate, but the present invention is not limited to this. For example, the other end of the head pressing arm is compressed. You may make it press down via a coil spring. In this case, it is needless to say that the compression coil spring needs to be arranged between the pivot shaft and the support wall, and the cam member and the motor need to be arranged below the roller.

[0053]

According to the first aspect of the present invention, the print head is automatically rotationally displaced in accordance with the inclination of the platen, and the parallelism with the platen is secured. The parallelism with the platen can be adjusted without any human intervention. Therefore, unlike the conventional case, there is no fear that the parallelism between the print head and the platen will vary, and the print quality can be improved.

Further, even if the mounting postures of the platen and the print head are individually changed due to expansion and contraction of each part due to the ambient temperature of the printer, the posture of the print head is automatically adjusted so as to follow the platen each time. Since the adjustment is performed, it is not necessary to frequently check the parallelism between the print head and the platen, and maintenance-free can be realized.

According to the structure described in claim 2, since only the rotating arm extending in the axial direction of the platen is arranged in the vicinity of the print head, directly above the print head,
As compared with the case where a cam device or the like for pressing this toward the platen is provided, the upper side of the print head is widely opened. Moreover, since the turning force of the rotating arm is transmitted to the print head via the shaft that serves as the pivot point of the print head, the pivot point of the print head and the input point of the force for pressing the print head toward the platen are common. In this respect as well, it is possible to form a compact portion around the support portion of the print head.

Therefore, the periphery of the print head can be widely opened to simplify the structure, and when the maintenance and inspection of the print head is performed, the pressing mechanism does not become an obstacle, and the maintenance and inspection can be performed. Workability is improved.

According to the third aspect of the present invention, the mechanism for rotating the rotating arm in the opposite direction against the urging force of the spring is eliminated from the periphery of the conveying path facing the platen and the print head. Therefore, the structure around the conveying path including the print head and the platen is simplified. Therefore,
The degree of freedom in arranging the print head and platen is increased, and when the ink ribbon is put in and taken out between the print head and the platen, the circumference of the print head is widely opened, making it easy to put in and take out this ink ribbon. Can be done.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a print head device according to an embodiment of the present invention is pressed against a platen roller.

FIG. 2 is a diagram showing a state in which the posture of the print head device changes according to the inclination of the platen.

FIG. 3 is a view seen from the direction of the line A in FIG.

FIG. 4 is a sectional view showing a positional relationship between a print head device and a platen roller.

FIG. 5 is a cross-sectional view showing a state in which the print head device is separated from the platen roller.

FIG. 6 is a perspective view showing a mechanism for pressing the print head device against the platen roller and releasing the print head device from the platen roller;

FIG. 7 is a view as seen from the direction of the line B in FIG.

FIG. 8 is an exploded perspective view showing an attachment structure of a platen support frame and a movable frame.

FIG. 9 is a perspective view of a print head device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main body frame, 6 ... Conveyance path, 10 ... Platen (platen roller), 28 ... Print head, 29a ... Opposing surface (front end surface), 33 ... Rotating arm (head pressing arm), 34
... Axis, 35 ... Support mechanism, 48 ... Spring (tensile coil spring), 51 ... Cam receiver (roller), 54
... Cam member, 55 ... Cam surface, 57 ... Motor.

Claims (3)

[Claims] 1. A body frame having a sheet conveyance path, a platen disposed in the conveyance path, and a heat generation pattern on a surface facing the platen, and the facing surface applies a predetermined pressure to the platen. In a line thermal printer having a print head to be pressed, the main body frame is rotatable about a central portion along the length direction of the print head around an axis intersecting the axis of the platen. A line thermal printer having a supporting mechanism for pivoting. 2. The support mechanism according to claim 1, wherein the support mechanism includes a rotating arm extending in the axial direction of the platen, and one end of the rotating arm opposes the platen and the other end of the rotating arm is opposite to the platen. The platen is extended to a position outside the platen in the axial direction, and a central part along the length direction of the print head is provided at one end of the rotating arm via a pivot shaft extending in a direction intersecting the axis of the platen. The other end of the rotating arm is rotatably connected to the body frame, and the rotating arm is connected between the other end of the rotating arm and the body frame. A line thermal printer comprising a spring for pressing one end of an arm toward the platen so as to press the facing surface of the print head against the platen. 3. The cam receiving portion according to claim 2, wherein a cam receiving portion is provided at the other end of the rotating arm, and the main body frame is in contact with the cam receiving portion,
A cam member having a cam surface for rotating the rotating arm in the direction of separating from the platen against the urging force of the spring, and by rotating the cam member,
A line thermal printer having a motor for bringing the cam surface into contact with the cam receiving portion.