JP2595808Y2 - Printing structure of thermal head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing structure of a thermal head for printing on paper by a thermal head.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 7, a printing structure of a thermal head of this type includes a platen roller 29 in contact with a printing surface of a thermal head 28, and a platen roller 2 as shown in FIG.
9 is provided with a pinch roller 26 which presses a thermal head 28 against the thermal head 2.
8 and is sent out, and printing is performed on the printing surface of the thermal head 28. As a means for pressing the pinch roller 26, the rotating shaft of the pinch roller 26 is supported by a bracket, and the entire bracket is pressed upward by a spring to move the pinch roller 26 from the position shown by the two-dot chain line in the drawing to the thermal head 28 side. They are pressed against each other.

[0003]

However, in the above-described conventional thermal head printing structure, the pinch roller 26 is inclined at an angle α with respect to the axial direction of the thermal head 28 due to a manufacturing error or an assembly error. The thermal head 28 with the pinch roller 26 tilted at the angle α.
, The pressing force between the printing surface of the thermal head 28 and the platen roller 29 fluctuates along the axial direction, causing a problem such as blurred characters and degraded printing quality. Was.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a printing structure of a thermal head with improved printing quality.

[0005]

In order to achieve this object, a printing structure of a thermal head according to the present invention is configured such that a printing surface of a thermal head is pressed against a platen and a sheet is inserted between the pressing surfaces. a printing structure of the thermal head for printing, comprising a roller for pressing the said thermal head printing surface and the platen, is provided a pair of brackets for supporting the rotation shaft of the roller at both ends of the rollers, the pair
Bracket can be rotated by one support shaft
One torsion coil wound around the support shaft
The pair of brackets are individually biased by an il spring
You .

[0006]

According to the present invention, since so as to support both ends of the roller in separate brackets, the case where the axial line direction of the thermal head rollers are tilted, superfluous is larger brackets of the slope Move to to correct the tilt.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a card reader employing a printing structure of a thermal head according to the present invention, and FIG.
3 is a plan view of the printing structure of the thermal head according to the present invention, FIG. 4 is a side view thereof, and FIG. 5 is an exploded perspective view thereof. In these figures, 1 is an opposing frame 1a,
1b, a card reader, 2 a card insertion slot for inserting and returning the magnetic card 3, 4 a card transport path communicated rearward from the card slot 3, and 5 and 6 a card transport path 4.
, The upper and lower drive rollers for stretching the transport belts 5 and 6 together with driven rollers (not shown), 9 for the drive motor, and 11 for the motor pulley 10 and the transmission pulley 12. It is the installed drive belt.

The drive roller 8 and the transmission gear 13 are axially mounted on the shaft 12a of the transmission pulley 12, and rotate integrally therewith. The transmission gear 13 is meshed with the drive gear 14.
A platen roller 29, which will be described later, is mounted on the shaft 14 a of the drive gear 14 to form a drive system from the motor 9. 16 is a punch unit, 17 and 18 are upper and lower card guides disposed at the rear end of the card transport path 4,
Reference numeral 20 denotes a printing unit which is a feature of the present invention.

Next, details of the printing unit 20 will be described. The printing unit 20 is generally composed of an electromagnetic solenoid 21, a drive lever 22, a pressure bracket 23, a pair of support brackets 24, 24, a coil spring 25, a pinch roller 26, a drive shaft 27, a thermal head 28, and a platen roller 29. I have. The electromagnetic solenoid 21 has a retractable plunger 21 having a hole 21b at the tip.
a is provided. A hole 2 is provided at one end of the drive lever 22.
2a, and a bent piece 22b having an L-shaped cross section is provided on the other end side.
Are protruded, and opposed D-shaped fitting holes 22c and mounting holes 22d are formed.

The press-contact bracket 23 includes a mounting portion 23a having mounting holes 23b disposed at both ends, and a mounting portion 23a.
and upper and lower connecting portions 23c and 23d for connecting a.
The support bracket 24 is formed with a pair of sandwiching pieces 24a, 24a facing each other at an interval, and a pair of large-diameter support holes 24b, 24b and a small-diameter support hole 24c penetrating both the sandwiching pieces 24a are provided. Have been. The coil spring 25 includes a pair of coil portions 25a, 25a and these coil portions 25a.
And a connecting portion 25b for connecting the coil portion 25a, and a distal end portion of the coil portion 25a is formed with an engaging portion 25c protruding outward. At the center of the pinch roller 26, a through hole 26a is provided. At both ends of the drive shaft 27, a pair of screw holes 27a, 27a penetrating the side surface are provided, and projecting ends 27b, 27c are formed at both end surfaces, and one projecting end 27c is extended. The extended portion 27d is formed in a D-cut cross section, and is provided with a screw hole 27e. 31 is a support shaft, 32 is an E-ring, and 33 is a bracket.

Next, a method of assembling the printing section 20 having such a configuration will be described. First, the thermal head 2
The bracket 33 to which the bracket 8 is attached is swingably supported by the frames 1a and 1b about the fulcrum 32a. Next, the support shaft 31 is connected to the support hole 24 of one support bracket 24.
c, the pinch roller 26 is inserted through the through hole 26a of the pinch roller 26 and the support hole 24c of the other support bracket 24, and the E-rings 32 are fastened to both ends to rotatably support the pinch roller 26 on both support brackets 24. Then, the coil portions 25a of the coil spring 25 are hooked between the holding pieces 24a of the support bracket 24 , and the hook portions 25c are fitted so as to engage with the lower ends of the outer holding pieces 24a.
Thereafter, the protruding end portion 27c of the drive shaft 27 is inserted into the support hole 24b of each of the support brackets 24, and is also inserted into the coil portion 25a of the coil spring 25.

Next, the connecting portion 23d of the pressure welding bracket 23
So as to insert the connecting portions 25b of the coil spring 25 to the lower end, the screw 3 6 inserted through the mounting hole 23b, by screwing the screw hole 27a, pressure bracket 23
Is fixed to the peripheral surface of the drive shaft 27. At this time, the support bracket 24 is moved by the spring force of the coil spring 25.
The upper surface 24d of the support bracket 24 is in contact with the lower end of the connecting portion 23c while being urged to rotate clockwise in FIG. 5 around the drive shaft 27. Next, the protruding ends 27b and 27c of the drive shaft 27 are rotatably supported by the frames 1a and 1b.

Thereafter, the fitting hole 22 of the drive lever 22 is
c is fitted into the extending portion 27d of the drive shaft 27, the screw 34 is inserted into the mounting hole 22d, and screwed into the screw hole 27e, thereby fixing the driving lever 22 to the extending portion 27d of the drive shaft 27 and integrally forming the same. To Then, the hole 22a of the drive lever 22 and the hole 21b of the plunger 21a are aligned and connected by the pin 35.

Next, the printing operation of the printing section having such a configuration will be described. When the magnetic card 3 is inserted from the card insertion slot 2, the insertion of the card is detected by detecting means (not shown), and the motor 9 is driven. The rotational drive of the motor 9 is transmitted to the drive roller 8 via the belt 11, moves the two conveyor belts 5 and 6, takes the card 3 into the reader 1, and conveys the card 3 on the card conveyance path 4. Card 3 transported
The magnetic information of the card 3 is read by a conventionally known magnetic head (not shown) provided in the reader 1,
Thereafter, new magnetic information is written.

The card 3 on which the new magnetic information is written is further conveyed, and when it reaches a predetermined position, the electromagnetic solenoid 21 is energized, the plunger 21a is retracted, and the support bracket 24 is moved by the urging force of the coil spring 25 4, the drive shaft 27 is rotated clockwise about the rotation center, and the thermal head 28
To the thermal head 2
8 is pressed against the platen roller 29. The platen roller 29 is rotationally driven by the motor 9 in the same manner as the drive roller 8.
, The magnetic card 3 is nipped between the platen roller 29 and the thermal head 28,
7 and is simultaneously printed by the thermal head.

At this time, as shown in FIG. 6, even if the thermal head 28 and the pinch roller 26 are inclined at an angle α with respect to the axial direction of the platen roller 29 as shown by a two-dot chain line in FIG. Rotation shaft 31 of pinch roller 26
Are supported by a pair of support brackets 24, 24 disposed at both ends of the pinch roller 26, and are individually imparted with the rotation behavior by the coil portion 25a of the coil spring 25, so that the one that is inclined is supported. Support bracket 24
Rotate more than the other support bracket 24, the inclination is corrected as shown by the solid line, and the pinch roller 26 uniformly presses the thermal head 28 along the axial direction. Platen roller 29
Is pressed uniformly along the axial direction,
Printing fading is prevented, and printing quality is improved.

When printing is completed, the motor 9 is driven to rotate in the reverse direction, the platen roller 29 also rotates in the reverse direction, the magnetic card 3 is transported to the card insertion slot 2 side, and the leading end of the magnetic card 3 is transported to the transport belts 7 and 8. When it reaches, the power supply to the electromagnetic solenoid 21 ends, the plunger 21a advances, and the drive shaft 27 is rotated counterclockwise in FIG. 4, and the support bracket 24 is opposed to the urging force of the coil spring 25. By rotating the pinch roller 31 away from the thermal head 28, the platen roller 2 of the thermal head 28 is rotated.
The pressure contact with 9 is released. The magnetic card 3 reversely fed by the conveyor belts 7 and 8 is punched in the punch unit 16 with punch holes corresponding to the newly written magnetic information, and is returned from the card insertion slot 2.

[0018]

As described above, according to the present invention, a roller for pressing the printing surface of the thermal head and the platen is provided, and a pair of brackets for supporting the rotating shaft of the roller are provided at both ends of the roller. Are supported by separate brackets, so even if the thermal head and the platen or the thermal head and the roller are inclined with respect to the axial direction of the thermal head, the bracket with the larger inclination can move extra. This corrects the inclination, so that printing defects such as blurred printing can be prevented, and the printing quality can be improved. Also,
The pair of brackets are rotated by one support shaft.
A single screw wound around this support shaft
Coil springs to urge a pair of brackets individually.
This makes it easy to assemble a pair of brackets.
You. In addition, the bias of the pair of brackets is
The number of parts can be reduced by using a spring.
Instead, assembly becomes easier.

[Brief description of the drawings]

FIG. 1 is a plan view of a card reader employing a printing structure of a thermal head according to the present invention.

FIG. 2 is a side view of the card reader employing the printing structure of the thermal head according to the present invention.

FIG. 3 is a plan view of a printing structure of the thermal head according to the present invention.

FIG. 4 is a side view of the printing structure of the thermal head according to the present invention.

FIG. 5 is an exploded perspective view of the printing structure of the thermal head according to the present invention.

FIG. 6 is a schematic front view showing an operation state in the printing structure of the thermal head according to the present invention.

FIG. 7 is a schematic front view showing an operation state in a printing structure of a conventional thermal head.

[Description of Signs] 1 Card reader 3 Magnetic card 4 Card transport path 9 Motor 20 Printing unit 21 Electromagnetic solenoid 22 Drive lever 23 Pressure contact bracket 24 Support bracket 25 Coil spring 26 Pinch roller 27 Drive shaft 28 Thermal head 29 Platen roller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 25/312 B41J 2/32 B41J 25/316

Claims (1)

(57) [Scope of request for utility model registration] In a printing structure of a thermal head for performing printing by pressing a printing surface of a thermal head and a platen and inserting a sheet between the pressing surfaces, a roller for pressing the printing surface of the thermal head and the platen is provided. A pair of brackets for supporting the rotating shaft of the roller are provided at both ends of the roller, and the pair of brackets is provided as one support shaft.
Rotatably supported by the
The one pair of brass is
A printing structure for a thermal head, characterized in that the brackets are individually urged .