JPH08187901A - Thermal head compression roller - Google Patents

Abstract

PURPOSE: To enable a thinned thermal head and a small diameter platen roller to be used for, in particular, reducing the size and weight of the apparatus by unifying compression forces between the recording paper or film wand the thermal head for printing in use of a thermosensible paper or heat transfer film. CONSTITUTION: The apparatus includes a thermal head 3 equipped with a folk for positioning a platen roller to the thermal head, the platen roller and a plurality of small-sized ancillary rollers 7 for compressing the platen roller 2 to be disposed In front and the rear at the displaced position of 30 deg. to 45 deg. with respect to the shaft of the platen roller not to be displaced in its center from the heater. In addition, it includes a folk having an elastic structure for compressing the ancillary rollers 7 via the platen roller 2 to the thermal head 1 and positioning the platen roller 2 and thermal head base 3, and an auxiliary roller base 8 having a stopper to be fitted in a lock part provided on the thermal head base 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure roller device for closely contacting a thermal head with a recording paper or film for printing on a thermal recording paper or a thermal transfer film in a low-priced facsimile or printer. The present invention relates to a structure of a pressure roller device using a thin thermal head and a plurality of auxiliary rollers that enable the use of a small-diameter platen roller to reduce the size and weight of the device.

[0002]

2. Description of the Related Art FIG. 8 is a schematic view of a conventional thermal head pressure roller device ((a) is a front view and (b) is a side view). A conventional thermal head pressure roller device is attached to a thermal head 1 ', and a platen shaft 4'having a central axis common to the central axis of the platen roller 2'is attached to a heater line 1a' of the thermal head 1 '(see FIG. (see c)) and shaft receiving metal fittings 20 composed of shaft receiving metal fittings 20a and 20b that are freely aligned in the height direction and are aligned so that the central axis 2a 'of the platen roller coincides with each other.
The platen roller 2 ′ is attached to the shaft receiving member 20, and the thermal head 1 ′ is pressed against the platen roller 2 ′ from the back of the thermal head 1 ′ by two to three springs.

Further, as shown in, for example, Japanese Patent Laid-Open No. 61-290072, a method called a backup roller is arranged on the platen roller to prevent the platen roller from warping as shown in FIG. 9B, or 61-
The thermal head shown in Japanese Patent No. 191237 has a proposal to obtain a uniform pressing force by increasing the number of springs in FIG. 9A on the assumption that the head has elasticity and warps in the pressing direction.

Further, as disclosed in Japanese Utility Model Laid-Open No. 05-013756, a backup roller is provided on a platen roller, and the backup roller is line-contacted at two points so as not to be displaced. Proposals have been made to have a positioning roller that holds the platen roller and the backup roller in a position where they make line contact.

[0005]

However, in the conventional thermal head pressure roller device shown in FIG. 8, the platen roller 2'and the thermal head 1'via the thermal recording paper.
The force for pressing is about 100 gf / 1 cm for the length of contact between the platen roller 2'and the thermal head 1 ', and about 3 Kg for the width of B4 and A4 size recording paper.
f is required. It is desired to use a thin thermal head and a small platen roller for low-priced facsimiles and printers in order to reduce the size and weight. However, when 3 kgf is applied to the thermal head, the thermal head 1'is warped as shown in FIG. Or, the platen roller 2'is bent.

In FIG. 9A, the thermal head 1'is thin and warps against pressure, the central pressing force is strong and both ends are weak, and the heat of the heater line 1a 'is transferred to the thermal recording paper at both ends. However, the heat-sensitive agent does not react sufficiently with heat and does not become black, resulting in large unevenness of black.

In FIG. 9 (b), the platen roller 2'is thin and warps against pressure, the pressing force at both ends is strong and the pressing force at the center is weak, causing similar deterioration of recorded image quality at the center.

Further, in FIG. 9 (c), the platen roller 2'is thin, and when the recording paper is rotated to feed it in the sub-scanning direction, the central portion bends to the opposite side in the sub-scanning direction due to the reaction to push out the recording paper, and the heater The line 1a 'and the central axis 2a' of the platen roller are deviated from each other, and the heat of the heater line 1a 'is not transferred to the thermal recording paper at the center, which causes similar deterioration of the recording image quality.

Further, the method disclosed in Japanese Patent Laid-Open No. 61-290072 requires a backup roller on the platen roller, which is not suitable for downsizing.

Assuming that the thermal head disclosed in Japanese Utility Model Laid-Open No. 61-191237 has elasticity and warps in the pressing direction, the number of springs in FIG. 9 (a) is increased to provide a uniform pressing force. The proposal sought requires that the platen roller have a resistance to this or an elasticity similar to that of a thermal head. Further, when the thermal head and the platen roller are similarly warped, it is unavoidable that the heater line 1a 'and the platen roller central axis 2a' are deviated during operation as shown in FIG.

Also, in the method disclosed in Japanese Utility Model Laid-Open No. 05-013756, in which the backup roller is provided with a positioning roller so as not to shift, the platen roller bends during operation, and the heater line 1a 'and the platen roller central shaft 2 are used.
It is unavoidable that a'is deviated and the recorded image quality is deteriorated.

The present invention has been made in view of the above-mentioned conventional circumstances. Therefore, the object of the present invention is to eliminate the above-mentioned drawbacks inherent in the prior art and to use a platen roller for a heater line of a thermal head. It is to provide a novel thermal head pressure roller device which makes it possible to make the applied pressure uniform and to prevent the pressurization centers of the heater line and the platen roller from deviating from each other, thereby improving the recording image quality. It is possible.

[0013]

In order to achieve the above object, a thermal head pressure roller device according to the present invention is a thermal recording apparatus having a thermal head and a platen roller, wherein a platen roller is provided in a heater line of the thermal head. The platen roller and platen roller are added together with the thermal head base that keeps the thermal head flat and has a platen shaft receiving part that can be freely aligned in the height direction and a lock part that fits into the stopper part of the auxiliary roller base. 30 ° to 45 ° to the axis of the platen roller so that the center of the platen roller is not displaced from the heater line
A plurality of small auxiliary rollers are arranged in front and rear of the recording paper feed direction at offset positions, and an auxiliary roller mounting portion having an elastic structure for pressing the auxiliary rollers to the thermal head via the platen roller is provided, and the platen roller and It comprises a platen shaft receiver for aligning the thermal head base and an auxiliary roller base having a stopper portion fitted to a lock portion provided on the thermal head base (corresponding to claim 1).

In the thermal head pressure roller device, the auxiliary roller is arranged in an auxiliary roller unit, and the auxiliary roller unit is attached to the auxiliary roller base via an elastic member such as rubber, cushion, leaf spring or the like. 2).

In the thermal head pressure roller device according to any one of claims 1 and 2, the thermal head base and / or the auxiliary roller base has a reinforcing bent portion in parallel to the recording width direction (corresponding to claim 3). .

In the thermal head pressure roller device according to claim 2, the auxiliary roller unit is positioned in the auxiliary roller base and / or the auxiliary roller unit at a position such that the auxiliary roller unit does not shift back and forth in the recording paper feeding direction. It has a claw (corresponding to claim 4).

In the thermal head pressure roller device according to any one of claims 1 to 4, the roller portion of the thermal head base and the stopper portion of the auxiliary roller base may be a recording paper of a thermal head application device such as a facsimile or a printer. It also serves as an opening / closing lock mechanism of the cover mold that opens and closes when mounted (corresponding to claim 7).

[0018]

In the present invention constructed as described above, the heater line of the thermal head and the central axis of the platen roller are accurately aligned by the platen shaft receiving portions provided in the thermal head base and the auxiliary roller base.
The lock part provided on the thermal head base and the stopper part provided on the auxiliary roller base maintain the aligned state, and by fitting, the repulsive force of the elastic structure part applied to the heater line of the platen roller and the thermal head Hold the pressure.

Since the plurality of auxiliary rollers press each auxiliary roller against the platen roller by the elastic structure, the platen roller is pressed with a uniform pressure. By providing a plurality of auxiliary rollers provided in front of and behind the axis of the platen roller in the feeding direction of the recording sheet, it is possible to prevent the axis of the platen roller from bending during the sub-scan feeding operation of the recording sheet.

The use of elastic members such as rubber, cushions and leaf springs instead of the elastic structure provided on the auxiliary roller base makes no difference in the action of pressing the platen roller against the thermal head.

The reinforcing bending portion provided in the thermal head base and / or the auxiliary roller base in parallel in the recording width direction receives a repulsive force against the pressure applied to the platen roller and the thermal head, and the thermal head base and / or the auxiliary roller. Prevent the base from warping.

Since the auxiliary roller base is attached to the cover mold of the main body of the thermal head application device and the thermal head base is attached to the base mold of the main body of the thermal head application device, the auxiliary roller base is opened when the cover mold is opened. Is separated from the thermal head together with the platen roller. When the cover mold is closed, the platen roller is aligned by the platen shaft receiving portion of the auxiliary roller base and the thermal head base, the lock portion of the thermal head base and the stopper portion of the auxiliary roller base are fitted, and the thermal head application device It can also function as an opening / closing lock mechanism for the cover mold of the main body.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described with reference to the drawings for each of its preferred embodiments.

FIG. 1 is a schematic structural view (front view) showing a first embodiment of a thermal head pressure roller device according to the present invention. 2A and 2B are structural explanatory views of the thermal head pressure roller device according to the present invention. FIG. 3 (a),
(B) is a structural diagram of an auxiliary roller base in the embodiment of the present invention. FIG. 4 is an operation explanatory view of the thermal head pressure roller device according to the present invention. 5A to 5D are explanatory views of the arrangement of the auxiliary roller according to the present invention. Figure 6
(A), (b) is a schematic structure figure when the thermal head pressure roller device concerning the present invention is built in a device.

As shown in FIG. 1, the first embodiment of the thermal head pressure roller device according to the present invention is a thermal recording apparatus having a thermal head 1 and a platen roller 2 and a heater line of the thermal head 1. A platen shaft receiving portion 3a and an auxiliary roller base 8 formed so as to be vertically movable in a height direction for aligning the platen roller 2 with 1a.
The thermal head base 3 has a lock portion 3b that fits or engages with the stopper portion 8e of FIG.

Further, the platen roller 2 and the platen roller 2 are pressurized so that the center of the platen roller 2 is the heater line 1.
a to the axis of the platen roller 2 so that
A plurality of small auxiliary rollers 7 are arranged in the feeding direction of the recording paper at positions deviated from 45 ° by 45 °. An auxiliary roller base 8 having an elastic structure portion for pressing the auxiliary roller 7 to the thermal head 1 via the platen roller 2, that is, a roller spring 8b, and an auxiliary roller mounting portion 8a for mounting the auxiliary roller 7 is provided. There is. The auxiliary roller base 8 further includes a platen shaft receiving portion 8d that aligns the platen roller 2 and the thermal head base 3 with each other, and a stopper portion that fits (engages) with a lock portion 3b provided on the thermal head base 3. 8e, and the reinforcing bending portion 8c is provided in parallel in the recording width direction.

The platen roller 2 has a metal platen shaft 4 having a high rigidity as an outer member made of silicon rubber, and the rotation is transmitted by a drive motor 6 via a platen gear 5 attached to the platen shaft 4 so that the platen roller 4 is thermally driven. A thermosensitive recording paper (see FIG. 6A) such as a roll thermosensitive paper 11 (not shown) which is pressed and sandwiched between the head 1 and the head 1 is fed in the sub-scanning direction. At this time, it is necessary to sufficiently press the thermal recording paper to the heater line 1a at about 100 gf / cm.

According to FIG. 2A, the platen roller 2 is pressed against the heater line 1a of the thermal head 1 from two directions by a plurality of auxiliary rollers 7, and FIG.
As shown in (b), the platen shaft receiving portion 3a of the thermal head base 3 and the platen shaft receiving portion 8d of the auxiliary roller base 8 position the platen shaft 4 relative to each other, and the lock portion 3b of the thermal head base 3 and the auxiliary portion Since the positioning is also performed by the stopper portion 8e of the roller base 8, the heater line 1a and the platen roller center shaft 2a can be accurately and reliably aligned.

The lock portion 3b and the stopper portion 8e also have a function of holding the pressure applied by the repulsive force of the elastic structure portion applied to the platen roller 2 and the heater line 1a of the thermal head 1.

Next, referring to FIGS. 3 (a) and 3 (b), in the elastic structure portion (roller spring 8b), a part of the auxiliary roller base 8 formed by sheet metal processing having high elasticity is used as an auxiliary roller mounting portion 8a. Roller spring 8 obtained as a leaf spring integrally configured
b can be used. The auxiliary roller base 8 has a reinforcing bent portion 8c for preventing warpage.

According to FIG. 4, the operation of the thermal head pressure roller device of the present invention constructed as described above is such that the pressure applied by the platen roller 2 to the thermal head 1 is P1,
When the platen roller 2 rotates, a feed output F1 that pushes out the thermosensitive recording paper is generated. The pressing force P1 is supported by the auxiliary roller base 8 via the auxiliary roller 7, and the platen roller 2
To prevent bending. The auxiliary roller base 8 disperses the pressing force of the platen roller 2 by the plurality of auxiliary rollers 7,
Since the auxiliary roller base 8 receives the entire width of the auxiliary roller base 8, a reinforcing bent portion 8c is provided to prevent warpage. Also the transmission output F1
At both ends is F by platen shaft receiver 3a
However, since it is added to the auxiliary roller 7 as F2 in the middle, it is fixed to the auxiliary roller base 8 so that the platen roller 2 is prevented from bending without being displaced.

The auxiliary roller 7 of the present invention is intended to disperse the pressing force and prevent the platen roller 2 from bending back and forth in the feeding direction as described above.
Similar effects can be obtained by disposing them facing each other or staggered as shown in (a), (b) and (c), (d).

Next, FIGS. 6A and 6B show examples in which the thermal head pressure roller device according to the present invention is mounted on a thermal head application device such as a facsimile or a printer.

Referring to FIG. 6, the auxiliary roller base 8 is attached to the cover mold 12 of the main body of the thermal head application device, and the thermal head base 3 is attached to the base mold 10 of the main body of the thermal head application device. The lock portion 3b of the head base 3 and the stopper portion 8e of the auxiliary roller base 8 also serve as an opening / closing lock mechanism of the cover mold 12 that opens and closes when the recording paper of the main body of the thermal head application device such as a facsimile or a printer is mounted. Has been done.

In FIG. 6A, the cover mold 12
When is opened, the auxiliary roller base 8 is separated from the thermal head 1 together with the platen roller 2. When the cover mold 12 is closed, the platen roller 2 is aligned with the auxiliary roller base 8 and the platen shaft receiving portions 3a and 8d of the thermal head base 3, and the lock portion 3b of the thermal head base 3 and the stopper of the auxiliary roller base 8 are aligned. The portion 8e is fitted (engaged), and the cover mold 12 is held in a closed state.

Referring to FIG. 6B, a release lever 13 for releasing the stopper portion 8e of the auxiliary roller base 8 from the lock portion 3b of the thermal head base 3 is provided on the side surface of the main body of the thermal head application device, and this opening. The lever 13 has an opening knob 14 which is connected to and operates the lever 13. When the opening knob 14 is lowered, the opening lever 13 opens the stopper portion 8e to release it from the lock portion 3b and pressurizes the platen roller 2. The pressure is released and the cover mold 12 is released.

FIG. 7 is a schematic view showing a second embodiment according to the present invention, and is an explanatory view of another pressurizing method of the auxiliary roller.

Referring to FIG. 7, the second embodiment of the present invention is an embodiment in which the means for pressurizing the platen roller 2 does not depend on the roller spring 8b. In the thermal head pressure roller device, the plurality of auxiliary rollers 7 are arranged in the auxiliary roller unit 16 and the auxiliary roller unit 16
Is attached to the auxiliary roller base 8 via a cushion sheet 17 which is an elastic member.
In addition, the auxiliary roller unit 16 has an auxiliary roller unit positioning claw 18 at a position where the auxiliary roller unit 16 does not shift back and forth in the recording paper feeding direction.
The operation and effect are the same as those of the first embodiment described above, and therefore the description thereof is omitted.

[0039]

As described above, according to the present invention,
In a small, thin, lightweight, low-priced facsimile and printer, a thermal head pressure roller device that equalizes the pressure applied by the platen roller to the heater line of the thermal head and does not deviate the center of pressure between the heater line and the platen roller. Is provided, which significantly improves recorded image quality.

Further, according to the present invention, the following various effects are specifically generated.

Since a small-diameter roller can be used, the device can be made compact and lightweight.

A uniform pressure is applied and the heat of the thermal head is evenly applied to the thermal paper, so that the printing performance is improved.

The connection between the pressure fitting and the positioning fitting also serves as an opening / closing lock mechanism for the cover of the apparatus and does not increase the cost.

It is possible to reduce the increase in assembly cost by eliminating the need for a pressure spring.

[Brief description of drawings]

FIG. 1 is a schematic structural view (front view) showing a first embodiment of a thermal head pressure roller device according to the present invention.

FIG. 2 is an explanatory view for explaining the structure of the first embodiment of the thermal head pressure roller device according to the present invention, in which (a) is a cross-sectional view showing the relationship between the thermal head, the auxiliary roller, and the platen roller; (B) is a side view showing the alignment of the heater and the platen roller.

3A and 3B are explanatory views of a structure of an auxiliary roller base according to the first embodiment of the present invention, FIG. 3A is an elevation view showing a part of the auxiliary roller base when viewed from below, and FIG. It is a side sectional view showing a part of auxiliary roller base.

FIG. 4 is an explanatory diagram illustrating an operation of the thermal head pressure roller device according to the present invention.

5A and 5B are explanatory views of the arrangement of auxiliary rollers according to the present invention, in which FIG. 5A is a front view showing a first arrangement example, FIG. 5B is a side view of FIG. 5A, and FIG. Front view showing an example of arrangement,
(D) is a side view of (c).

FIG. 6 is a schematic structural portion inside the apparatus when the thermal head pressure roller apparatus according to the present invention is incorporated into the apparatus,
(A) is a side sectional view of the apparatus, and (b) is an explanatory view of an opening mechanism of an auxiliary roller base and a thermal head base.

FIG. 7 is a schematic structural diagram of a main part showing a second embodiment of the thermal head pressure roller device according to the present invention.

FIG. 8 is a schematic configuration diagram of a conventional thermal head pressure roller device, in which (a) is a front view and (b) is a side view.

FIG. 9 is an operation explanatory view of a thermal head pressure roller device in a conventional example, (a) and (b) are explanatory views of a warp,
(C) is an explanatory view of bending.

[Explanation of Codes] 1, 1 '... Thermal head 1a, 1a' ... Heater line 2, 2 '... Platen roller 2a, 2a' ... Platen roller central shaft 3 ... Thermal head base 3a ... Platen shaft receiving portion 3b ... Lock portion 4, 4 '... Platen shaft 5, 5' ... Platen gear 6, 6 '... Drive motor 7 ... Auxiliary roller 8 ... Auxiliary roller base 8a ... Auxiliary roller mounting portion 8b ... Roller spring 8c ... Reinforcing bent portion 8d ... Platen shaft receiving portion 8e ... Stopper part 10 ... Base mold 11 ... Roll thermal paper 12 ... Cover mold 13 ... Opening lever 14 ... Opening knob 15 ... Housing mold 16 ... Auxiliary roller unit 17 ... Cushion sheet 18 ... Auxiliary roller unit positioning claw 20 ... Shaft receiving metal fitting 20a, 20b ... Shaft receiving metal fitting 21 ... Spring

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B41J 11/04 13/00

Claims (7)

[Claims] 1. A thermal recording device having a thermal head and a platen roller, which is fitted to a platen shaft receiving portion and a stopper portion of an auxiliary roller base which are freely movable in a height direction for aligning the platen roller with a heater line of the thermal head. A thermal head base having a lock portion for maintaining and holding the thermal head flat, the platen roller and the platen roller are pressed by 30 ° with respect to the axis of the platen roller so that the center of the platen roller is not displaced from the heater line. A plurality of small auxiliary rollers are arranged in front of and behind the recording paper in the feeding direction of the recording paper at a position deviated by 45 ° from each other, and an auxiliary roller mounting portion having an elastic structure for pressing the auxiliary rollers to the thermal head via the platen roller is provided. Is provided for aligning the platen roller with the thermal head base. A thermal head pressure roller device comprising: a Latin shaft receiver; and an auxiliary roller base having a stopper portion that fits into a lock portion provided on the thermal head base. 2. The auxiliary roller is arranged in an auxiliary roller unit, and the auxiliary roller unit is made of rubber, a cushion,
The thermal head pressure roller device according to claim 1, further characterized in that the thermal head pressure roller device is attached to the auxiliary roller base via an elastic member such as a leaf spring. 3. The thermal head additive according to claim 1, further comprising a reinforcing bent portion in parallel with the recording width direction in the thermal head base and / or the auxiliary roller base. Pressure roller device. 4. The auxiliary roller unit positioning claw is further provided on the auxiliary roller base or on the auxiliary roller unit at a position where the auxiliary roller unit does not shift back and forth in a recording paper feeding direction. 2. The thermal head pressure roller device according to 2. 5. The thermal head pressure roller according to claim 1, wherein the plurality of auxiliary rollers are arranged so as to face each other in the rotation direction of the platen roller. apparatus. 6. The thermal head pressure roller device according to claim 1, wherein the plurality of auxiliary rollers are arranged alternately with respect to the rotation direction of the platen roller. . 7. The auxiliary roller base is a facsimile,
The thermal head application device such as a printer is attached to a cover mold that opens and closes when the recording paper is mounted, the thermal head base is attached to the base mold of the thermal head application device body, and the lock portion of the thermal head base and the thermal head base are attached. The thermal head pressure roller device according to any one of claims 1 to 4, wherein the stopper portion of the auxiliary roller base is an opening / closing lock mechanism of a cover mold of the main body of the thermal head application device.