JPH10119324A - Thermal line printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with a space which is otherwise necessary for accommodating a shaft having a cam portion disposed between a head support member and a head pressing spring and for accommodating a groove, by providing a stopper on a chassis of a thermal printer main body, said stopper being adapted to prevent the head support member from displacing an excessive amount, with the use of a special contacting portion. SOLUTION: A central projection 1a is provided on a chassis 1 to form a support section for freely pivotally supporting a a head supporting member 6. A first stopper 1b is provided above a plurality of exothermic elements 7a of the central projection 1a and above the chassis 1 which is substantially parallel to the exothermic elements 7a, so as to prevent the support member 6a from moving up an excessive height when the head moves up. With the use of the above structure, it is possible not only to use merely a very small space to form a head-up mechanism capable of releasing a pressure contact between the thermal head 7 and the platen roller 2, but also to reduce the number of elements required to form the thermal printer and thus simplify assembling operation because of a simplified structure. Further, it is possible to alleviate a possible difference between left and right rising amounts of the head of the head support member 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small thermal line printer used as an output terminal of a POS, ECR, handy terminal, measuring instrument, or the like.

[0002]

2. Description of the Related Art FIG. 9 is a perspective view showing the overall structure of a conventional thermal line printer, and FIG. 10 is a cross-sectional view showing the conventional thermal head press-contact and press-release operations.

In FIG. 9, reference numeral 101 denotes a chassis of a thermal line printer main body, 102 denotes a cylindrical platen roller, 103 denotes a bearing of the platen roller 102, 104 denotes a motor serving as a driving source for rotating the platen roller 102, 105a and 105b. Is a gear train for transmitting the rotational driving force of the motor 104 to the platen roller 102.

Reference numeral 107 denotes a thermal head, and 106 holds the thermal head 107. The bearings 103 are fitted to both ends of the thermal head 107 and guide grooves 106a and 106b for positioning the heating element row 107a of the thermal head 107 and the axis of the platen roller 102.
(Not shown) and a head supporting member provided with locking portions 106d and 106e, and 109a and 109b are used to move the thermal head 107 to the platen roller 1 via the thermal recording paper 108.
A torsion coil spring 110 for pressing against the reference numeral 02 is a lever 111 rotatably attached to the chassis 101,
Rotates in conjunction with the lever 110, and the torsion coil spring 1
The shaft is provided with a cam-shaped portion attached so as to penetrate between the head supporting members 106 and 09a and 109b.

[0005] A chassis 101a is provided as a fulcrum for swingably supporting the head support member 106.
It is a central projection provided in.

The printing mechanism and the head-up mechanism of the conventional thermal line printer configured as described above will be described.
This will be described with reference to FIG.

FIG. 10A is a cross-sectional view showing the state of pressure contact between the thermal head 107 and the platen roller 102. First, the printing mechanism will be described.

In FIG. 10A, the thermal head 1
Reference numeral 07 is in pressure contact with the platen roller 102 via thermal recording paper 108 by torsion coil springs 109a and 109b.
At 06, the heating element row 107a is aligned and fixed to a line connecting the centers of the guide grooves 106a and 106b provided at both ends of the head support member 106, and thus provided at both ends during pressure contact. Guide grooves 106a and 10
6b is fitted to the bearing 103 of the platen roller, so that the positional relationship where the heating element array 107a and the platen roller 102 can perform normal printing is maintained, and the timing of heat generation of the heating element array 107a by driving and energizing the motor 104 is controlled. Thus, the thermal head 107 and the platen roller 102
The printing is performed on the thermosensitive recording paper 108 sandwiched between them.

Next, a mechanism for pressing the thermal head 107 and the platen roller 102 will be described.

As shown in FIG. 10A, in a head-down state in which the printable thermal head 107 and the platen roller 102 are in pressure contact with each other, the head support member 106 to which the thermal head 107 is fixed is in contact with the central projection 101a. pressure portion of the first contact portions one portion of the Z ₀ point and the platen roller 102 and the heating element column 107a, namely the platen roller 1
02, which has a linear contact portion with the axial surface of the torsion coil spring 109 for pressing against the platen roller 102.
The points of action X (Y) of the a and 109b correspond to the pressure contact portion between the heating element row 107a and the platen roller 102 and the central projection 101.
located between positions a, it is always supported by the linear contact portion between the heating element row 107a and Z ₀ point and the platen roller 102.

Subsequently, the thermal head 1 necessary for inserting the thermal recording paper 108 and cleaning the heating element array 107a is required.
A head-up mechanism for releasing the pressure contact between the platen roller 07 and the platen roller 102 will be described with reference to FIG.

In FIG. 10A, when the shaft 111 provided with the cam-shaped portion is rotated by the lever 110 shown in FIG. 9, the torsion coil springs 109a and 109b are rotated as shown in FIGS. 10B and 10C. Is pushed up by the lift amount of the cam of the shaft 111, and at the same time, the spring 109
a, 106e, which locks 109a, 109b
, The head support member 106 is lifted up, and the thermal head 107 is detached from the platen roller 102 to release the pressed state.

[0013]

However, in the above-described head-up mechanism of the thermal head and the platen roller in the conventional thermal line printer, a shaft having a cam-shaped portion is provided between the head supporting member and the spring for pressing the thermal head. By doing so, the center projection on the thermal line printer main body, which is also a fulcrum of rotation even when the head is raised, suppresses the swing of the head support member even at one point, and it is possible to uniformly remove both ends and the entire head support member from the platen roller. Although it was possible, it was necessary to secure a space for arranging the shaft, and it was difficult to reduce the size of the thermal line printer main body with a strong market demand, and a shaft having the cam-shaped portion as a part was required. In addition, the assembly method is to install the shaft after installing the torsion coil spring. Improved reduction and assemblability had the problem that was difficult.

The present invention solves such a conventional problem,
It is an object of the present invention to reduce the size of a thermal line printer and to provide an inexpensive thermal line printer by realizing a mechanism for pressing and releasing a thermal head and a platen roller in a small space with a simple structure. .

[0015]

SUMMARY OF THE INVENTION In order to solve this problem, a thermal line printer according to the present invention comprises a head support member holding a thermal head at a lower end center portion, a side upper portion, and a lower end side portion, respectively. A cam, which is provided with a second contact portion on a bottom portion of the chassis, and a protrusion serving as a fulcrum portion for contacting with the first contact portion and swingably supporting the head support member. A lever for releasing the head support member by providing a part on the axis of the platen roller,
In this configuration, a stopper is provided on the chassis to abut on the third contact portion and regulate the detachment of the head support member.

According to the present invention, the mechanism for pressing and releasing the thermal head and the platen roller can be realized in a smaller space than before, the number of parts of the thermal line printer can be reduced, and the assembly is simplified. Become.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to a first aspect of the present invention is directed to a platen roller rotatably supported by a chassis serving as a main body for conveying recording paper, and a drive for rotating the platen roller. And a line-type thermal head for performing printing on the recording paper, and first, second, and third contact portions are provided at the center of the lower side, above the side, and at the end of the lower side, respectively, and are parallel to the platen roller. A head support member, an elastic body that presses the line type thermal head against a platen roller via recording paper, and a first contact portion provided on the head support member to contact the head support member. A projection provided on the bottom of the chassis so as to be a fulcrum for swingably supporting, and a cam contacting a second contact portion provided on the head support member are provided. A lever rotatably mounted on the line, and provided on the chassis so as to contact a third contact portion of a head support member which is pushed up by a cam portion by the rotation of the lever and moves away from the platen roller. The mechanism consists of a stopper provided, and not only can the pressure contact and release mechanism between the thermal head and the platen roller be realized in a small space, but also the number of parts of the thermal line printer can be reduced and assembly can be simplified. Has an action.

According to a second aspect of the present invention, in the first aspect of the present invention, third lower ends of the head support member are provided at both ends.
Are provided on the chassis, and stoppers for respectively contacting the two third contact portions are provided on the chassis, so that a mechanism for pressing and releasing the thermal head and the platen roller can be realized in a small space. In addition, the number of parts of the thermal line printer can be reduced and the assembling can be simplified, and the difference between the right and left head-up amounts of the head support member can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a perspective view showing an overall configuration of a thermal line printer according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a thermal head press-contact state of the thermal line printer according to the embodiment. FIGS. 3 to 5 are cross-sectional views for explaining the thermal head press-contact and press-release operations of the thermal line printer according to the embodiment.

In FIG. 1, 1 is a chassis of a thermal line printer main body, 2 is a cylindrical platen roller, 3 is a bearing of the platen roller 2, 4 is a motor serving as a driving source for driving the platen roller 2 to rotate, 5a and 5b. Is a gear train for transmitting the driving force of the motor 4 to the platen roller 2. 7
Is a thermal head, 6 is a guide groove 6a, 6b (6a) for holding the thermal head 7 and engaging the bearings 3 at both ends to position the heating element row 7a of the thermal head 7 at the axis of the platen roller 2. A head supporting member 9a, 9b provided on the other end side, not shown), is a torsion coil spring for pressing the thermal head 7 against the platen roller 2 via the thermal recording paper 8, and 10 is a platen roller shaft. This is a lever having a cam-shaped portion rotatably mounted.

Reference numeral 1a denotes a central projection provided on the chassis 1 so as to serve as a fulcrum for swingably supporting the head support member 6, and 1b extends in a direction substantially parallel to the heating element row 7a of the central projection 1a. This is a first stopper provided on the chassis 1 so as to restrict a certain amount or more of the head supporting member 6 from rising when the head is raised.

The press-contact state of the thermal head 7 and the platen roller 2 of the thermal line printer configured as described above will be described with reference to FIG.

In FIG. 2, the head support member 6 to which the thermal head 7 is fixed is attached to the center projection 1 of the chassis 1.
pressure portion between the one location and the platen roller 2 and the heating element row 7a of the contact portions Z ₀ point with a, i.e. has a linear contact portion between the axial direction of the surface of the platen roller 2, the thermal head 7 platen roller 2 Torsion coil spring 9 for pressing against
a, since the working point X (Y) point 9b is located between the heating element row 7a and pressure portion and the central projection 1a of the platen roller 2, always Z ₀ point when pressure is and the platen roller 2 and the heating element It is supported so that a surface is formed by a linear contact portion with the row 7a, that is, one point and a straight line.

Next, the thermal head 7 and the platen roller 2
About the detailed mechanism to release the pressure contact from the pressure contact state of
This will be described with reference to FIGS.

FIGS. 3A to 3C are a front view, a side view, and a bottom view showing a state in which the thermal head 7 is in pressure contact with the platen roller 2. In FIGS. 3A to 3C, FIG. Points A ₀ and B ₀ indicate both end positions of the linear contact portion between the heating element row 7 a and the platen roller 2, and point Z ₀ indicates a first contact portion between the head support member 6 and the central protrusion 1 a provided on the chassis 1. , the points X, Y is a torsion coil spring 9a, the point where the spring force acts in 9b, the point C ₀ platen roller head support member 6 is cam-shaped portion of the lever 10 when to release the pressure contact of the thermal head 7 and the platen roller 2 The point D ₀ is a second contact portion between the cam-shaped portion of the lever 10 and the head support member 6 that are pushed up in the direction of detaching from the head 2, and a point D ₀ is a certain amount or more when the cam-shaped portion of the lever 10 pushes up the head support member 6 Regulate A third contact portion between the first stopper 1b and the head support member 6 provided on earthenware pots.

In this state where the thermal head 7 is in pressure contact with the platen roller 2, the points X,
The spring force acting on Y is a straight line connecting point Z ₀ and points A ₀ and B ₀ ,
That is, it is supported by the central projection 1a and the surface of the platen roller 2. In this state, both the point C ₀ and the point D ₀
Does not contact the first stopper portion 1b or the cam-shaped portion of the lever 10.

FIGS. 4A to 4C are a front view, a side view, and a bottom view showing a transition period of the head release. A point D ₀ on the head support member 6 holding the thermal head 7 is the first. 1 shows the operation immediately before contact with the stopper 1b. When the head is released, when the lever 10 is rotated, the cam-shaped portion thereof comes into contact at a point C ₀ , and when the lever 10 is further rotated, the head supporting member 6 is pushed up using a line connecting the points A ₀ and Z ₀ as a rotation axis.

That is, the points C ₀ and B _{0 of the} head support member 6
Is pushed up in a direction to separate from the platen roller 2. At this time, the linear A ₀ Z ₀ only point D ₀ also the product of the ratio of the distance from a point D ₀ for the distance to the straight line A ₀ Z ₀ from the amount of movement and the point C ₀ up linearly A ₀ Z ₀ of the point C ₀ It is pushed up in the rotation direction until it comes into contact with the first stopper 1b as a rotation axis. In this state, the spring force acting on the points X and Y is the point C ₀ and the straight line A ₀ Z
₀ is supported in pressure contact with the heating element row 7a and the platen roller 2 at point B ₀ is released.

FIG. 5 (a) ~ (c) is a front view showing an operation state after the first stopper 1b the head supporting member 6 at the time of releasing the head pressure is in contact at point D _0, side view, in bottom view When the lever 10 is further rotated after the point D ₀ comes into contact with the first stopper 1b, the head supporting member 6 moves to the point Z ₀ ,
Point D ₀ and the point C ₀ and the rotation axis a line connecting, with the point B ₀ is pushed in a direction to further detached from the platen roller 2, the distance from the movement and the point C ₀ of the point C ₀ up straight Z ₀ D ₀ the point a ₀ only the product of the ratio of the distance from point a ₀ up straight Z ₀ D ₀ for is pushed straight Z ₀ D ₀ as a rotational axis.

In this state, the spring force acting on the points X and Y is supported by the point C ₀ and the straight line Z ₀ D ₀ , and the pressure contact at the point A ₀ is released. Therefore, the thermal head 7 can be detached from the surface of the platen roller 2, and the press contact state can be completely released.

As described above, the head-up mechanism for detaching the thermal head 7 from the platen roller 2 and releasing the pressure contact can be realized in a small space, and the structure is simple. The effect that the number of points can be reduced and the assembling can be simplified can be obtained.

(Embodiment 2) FIGS. 6 to 8 are cross-sectional views for explaining thermal head press-contact and press-release operations of a thermal line printer according to a second embodiment of the present invention. Is the same as that shown in FIGS. 3 to 5 except for the point E ₀ , and a detailed description thereof will be omitted below.

FIGS. 6A to 6C are a front view, a side view, and a bottom view showing a state in which the thermal head 7 is in pressure contact with the platen roller 2. In FIGS. 6A to 6C, FIG. The point E ₀ rotates the straight line A ₀ Z ₀ at a point on the head support member 6 which is substantially symmetrical with the point D ₀ with a line passing through the point Z ₀ and perpendicular to the straight line A ₀ B ₀ as the axis of line symmetry. Point C ₀ is the lever 10
When the head support member 6 is pushed up by the cam-shaped portion of
Is a point of contact with the second stopper 1c provided on the chassis 1 so as to restrict the displacement of a certain amount or more.

In this state, the spring forces acting on the points X and Y are supported by the point Z ₀ and the straight line A ₀ B ₀ , and the points C ₀ , D ₀ , and E ₀ are the cam-shaped portions of the lever 10. And the first stopper 1b and the second stopper 1c on the chassis 1 are not in contact with each other.

FIGS. 7A to 7C are a front view, a side view, and a bottom view showing a transition period of head release.
When the lever 10 is rotated, its cam-shaped portion comes into contact at a point C ₀ , and when the lever 10 is further rotated, the head supporting member 6 uses the line connecting the point A ₀ and the point Z ₀ as a rotation axis, and the point C ₀ and the point B ₀ It is pushed up in a direction to separate from the roller 2. At this time, the points D ₀ and E ₀ are defined by the first stopper 1 using the straight line A ₀ Z ₀ as the rotation axis as described with reference to FIGS.
b or the second stopper 1c.

Here, the point D _{0 corresponds} to the first stopper 1 b
For a description if the point E ₀ before the contact configured to contact a second stopper 1c to. In this state, the spring force acting on the points X and Y is the point C ₀ and the straight line A ₀
It is supported at Z ₀ , and the pressure contact at point B ₀ has been released.

FIG. 8 (a) ~ (c) is a front view showing an operation state after the second stopper 1c and the head supporting member 6 at the time of releasing the head pressure is in contact at point E _0, side view, in bottom view When the lever 10 is further rotated after the point E ₀ comes into contact with the second stopper 1c, the spring force acting on the points X and Y becomes supported by the point A ₀ and the straight line C ₀ E ₀ , With the movement of C ₀ , the point D ₀ moves around the straight line C ₀ E ₀ as a rotation axis until it contacts the first stopper 1b.

At this time, the point Z ₀ is no longer in contact with the central projection 1a, and when the rotation of the lever 10 is further continued,
The head support member 6 has a point C ₀ with the straight line D ₀ E ₀ as the axis of rotation.
The point A ₀ is displaced to the separating direction from the platen roller 2 along with the movement, to release the head pressure. In this state, the spring force acting point X, the Y is supported at point C ₀ and the straight line D ₀ E _0.

As described above, the head-up mechanism for detaching the thermal head 7 from the platen roller 2 and releasing the pressure contact can be realized in a small space, and the number of parts of the thermal line printer can be reduced due to the simple structure. In addition to the effect that the head support member 6 can be assembled easily, the difference between the right and left head-up amounts of the head support member 6 can be reduced.

In the above description, the elastic body has been described as a configuration using two torsion coil springs (9a, 9b). However, as another method, a similar effect can be obtained by using a leaf spring. It is.

Further, the configuration in which the lever 10 is rotatably mounted on the platen roller shaft has been described. However, as another method, the same effect can be obtained by a configuration in which the lever 10 is rotatably mounted on the chassis 1.

[0042]

As described above, in the thermal line printer according to the present invention, the displacement of the head support member over a certain distance caused by pushing up the second contact portion of the head support member with the cam-shaped portion of the lever is described. By forming the first stopper regulated by the third contact portion on the chassis of the thermal line printer main body, a cam-shaped portion is provided between the conventional head support member and the head pressure contact spring. No need for a shaft and space for the groove
The effect of easily realizing the miniaturization of the thermal line printer and the effect of realizing the cost reduction of the thermal line printer because the structure is simple and easy to assemble can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overall configuration of a thermal line printer according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the thermal head pressed state.

3A is a front view for explaining the thermal head press-contact and press-release operations, FIG. 3B is a side view, and FIG.

FIG. 4A is a front view for explaining the thermal head press-contact and press-release operations, FIG. 4B is a side view, and FIG.

5A is a front view for explaining the thermal head pressure contact and pressure contact release operation, FIG. 5B is a side view, and FIG.

FIG. 6A is a front view for explaining thermal head pressure contact and pressure contact release operations according to a second embodiment of the present invention; FIG. 6B is a side view;

7A is a front view for explaining the thermal head pressure contact and pressure contact release operation, FIG. 7B is a side view, and FIG.

8A is a front view for explaining the thermal head pressure contact and pressure contact release operation, FIG. 8B is a side view, and FIG.

FIG. 9 is a perspective view showing the overall configuration of a conventional thermal line printer.

FIG. 10 is a sectional view showing the thermal head press-contact and pressure-releasing operation of the conventional thermal head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Chassis 1a Central projection 1b First stopper 1c Second stopper 2 Platen roller 3 Bearing 4 Motor 5a, 5b Gear train 6 Head support member 6a Guide groove 6b Guide groove 7 Thermal head 7a Heating element array 8 Thermal recording paper 9a, 9b Torsion coil spring 10 Lever Z ₀ First contact part C ₀ Second contact part D ₀ Third contact part E ₀ Fourth contact part A ₀ Left end of linear contact part B ₀ Right end of linear contact part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Isamu Yukimatsu 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] A platen roller rotatably supported by a chassis serving as a main body to convey a recording sheet; a driving section for rotating the platen roller; and a line type thermal head for printing on the recording sheet And a head support member disposed in parallel with the platen roller by providing first, second, and third contact portions at the lower central portion, the upper side edge, and the lower edge portion, respectively, and the line type thermal head And an elastic body that presses the platen roller through the recording paper, and a fulcrum that contacts the first contact portion provided on the head support member and supports the head support member in a swingable manner. A lever provided rotatably on the axis of a platen roller with a projection provided at the bottom of the platen roller, and a cam portion contacting a second contact portion provided on the head support member. A thermal line printer comprising a stopper provided on the chassis so as to come into contact with a third contact portion of a head support member which is pushed up by a cam portion by the rotation of the lever and moves away from the platen roller. 2. A head support member having a third end on each lower end thereof.
2. The thermal line printer according to claim 1, wherein the contact portions are provided, and stoppers respectively contacting the two third contact portions are provided on the chassis.