JPH09207417A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid wasteful use of an ink ribbon due to ineffective feeding by providing a thermal head support member that freely comes in contact with and leaves away from a platen and faces the platen, and a driver that moves the thermal head supporting member to let the thermal head come close to the platen. SOLUTION: Before printing, a recording medium 14 is transferred and located between a platen 4 and a pinch roller 17 by a driving roller 15 and a driven roller 16 that are driven by a motor 13 and then positioned at a specified printing position by detecting the front end of the recording medium 14 by a sensor 29. A cam 6 of a thermal head driver rotates clockwise by the operation of a motor and a thermal head 14 comes close to the platen 4 with swing motion of the thermal head support member 24 due to the tensile force of a spring 5. In this state, the cam 6 continues to rotate clockwise to let the thermal head 3 come in press contact with the recording medium 14, and the engagement of a click 25c of a detent 25 with a ratchet wheel 28 is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer in which a recording medium such as a tube or a label tape is conveyed and a roll film-shaped ink ribbon is wound by a motor, and more specifically, the ink ribbon is wound. Regarding improvement of means.

[0002]

2. Description of the Related Art Conventionally, an apparatus of this type having a structure shown in FIG. 4 has been known, and its details will be described. Reference numeral 1 denotes a thermal head support member, and this thermal head support member 1 is provided so that one end portion 1a thereof can be swung about an axis 2, and a thermal head 3 is opposed to a platen 4 at a substantially central portion thereof. It is provided at a position where the platen 4 is provided and is biased toward the platen 4 by the spring 5. The convex portion 1c of the other end portion 1b of the thermal head support member 1 is adapted to engage with the cam 6 by the bias of the spring 5. Reference numeral 7 denotes an ink ribbon. The ink ribbon 7 is supplied from an ink ribbon supply roll 8 and sent in the direction of arrow A, passes between the thermal head 3 and the platen 4, and is taken up by an ink ribbon take-up roll 9. . The ink ribbon take-up roll 9 is driven by a motor 13 via gears 10, 11a, 11b and 12. The ink ribbon supply roll 8 is provided with a brake mechanism (not shown) to prevent the slack of the ink ribbon 7, and the ink ribbon take-up roll 9 is provided with a torque limiter 9a so that the take-up force is increased. It does not exceed the specified value.

A recording medium 14 such as a tube or a label tape has a driving roller 15 and a driven roller 16, a thermal head 3 and a platen 4, and a platen 4 and a pinch roller 17.
It is sent in the direction of arrow B through the space. Platen 4 is gear 1
The drive roller 15 is driven by the motor 13 via 0, 11a, 11b, 18a, 18b, 19 and further via gears 20, 21, 22.

The operation of the conventional example will be described. When performing thermal printing on the recording medium 14, the thermal head 3 is separated from the platen 4 by sliding the cam 6 and the convex portion 1c of the thermal head supporting member 1 by rotation of the cam 6 in the counterclockwise direction, and the driving roller is driven. The recording medium 14 is fed to the print start position by the reference numeral 15 and the driven roller 16 and the platen 4 and the pinch roller 17. Next, the cam 6 rotates in the clockwise direction, the thermal head 3 is brought into close contact with the recording medium 14 along the platen 4 by the tension of the spring 5, and the thermal printing is performed with the rotation of the platen 4 in the clockwise direction by the drive of the motor 13. I do.

[0005]

However, since the same motor 13 is used as a drive source for the conveyance of the recording medium 14 and the winding of the ink ribbon 7 in the above-mentioned thermal printer, the thermal head 3 is separated from the platen 4. However, even if the recording medium 14 is not printed, the ink ribbon 7 is also wound up when the recording medium 14 is conveyed, which causes a problem of waste of the ink ribbon 7.

[0006]

In a thermal printer in which the conveyance of a recording medium and the winding of an ink ribbon are driven by the same motor, and a torque limiter is provided on an ink ribbon winding roll, the thermal printer is brought into contact with and separated from a platen. A thermal head support member that freely supports the thermal head that faces the platen and a thermal head driving unit that moves the thermal head support member to move the thermal head closer to the platen are provided, and the thermal head is separated from the platen when not printing. The means for restraining the rotation of the ink ribbon take-up roll is driven in association with the operation of the thermal head driving means when moving the thermal head support member.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION When printing is performed in the present invention, first, the thermal head is moved together with the thermal head support member toward the platen by the thermal head driving means to bring the thermal head into close contact with the recording medium along the platen. Next, the platen and the ink ribbon take-up roller are rotated by driving the motor, and printing is sequentially performed. When the recording medium is conveyed after printing is completed, the thermal head driving means moves the thermal head together with the thermal head supporting member away from the platen, and in conjunction with the operation of the thermal head driving means, the ink ribbon take-up roll is moved. The means for restraining the rotation of is driven. At this time, the drive of the ink ribbon take-up roll from the motor is released by the torque limiter, so that the rotation of the ink ribbon take-up roll is stopped, the ink ribbon is not taken up, and only the recording medium is conveyed. It will be.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 and FIG. 2 are embodiments of the present invention. FIG. 1 is a plan view when restraining winding of an ink ribbon of a thermal printer, and FIG. It is a plan view when performing printing. Hereinafter, the same components as those in the conventional example are denoted by the same reference numerals.

Reference numeral 24 denotes a thermal head supporting member, and in addition to the shape of the conventional thermal head supporting member 1, the thermal head supporting member 24 has a protrusion 24a protruding upward (in the paper surface direction). Axis 2, thermal head 3,
Platen 4, spring 5, cam 6, ink ribbon 7,
Ink ribbon supply roll 8, ink ribbon take-up roll 9, torque limiter 9a, gears 10, 11a, 11b,
12, 18a, 18b, 19, 20, 21, 22, motor 13, recording medium 14, drive roller 15, driven roller 1
6. The pinch roller 17 is the same as the conventional one.

Reference numeral 25 denotes a stop claw, and a projection 25a is provided on the stop claw 25 so that the inner side surface 25b has the projection 2
4a, a claw portion 25c is provided, and the claw portion 25c is provided so as to be swingable around a shaft 26 and is biased in the clockwise direction by the tension of a spring 27. The tension of the spring 5 that swings the thermal head support member 24 is larger than the tension of the spring 27 that swings the stop claw 25. When the thermal head support member 24 swings in the platen 4 direction, the protrusion 24
The engagement between the a and the projection 25a resists the tension of the spring 27, and the stop claw 25 is also interlocked and swings.

28 is a ratchet wheel of a gear,
The ratchet wheel 28 has teeth that engage with the claw portions 25c of the stop claw 25, and are provided on the ink ribbon take-up roll 9.

FIG. 1 shows a state before printing. The thermal head 3 is located away from the platen 4, and the stop claw 2
The claw portion 25c of No. 5 meshes with the teeth of the ratchet wheel 28 and restrains the rotation of the ink ribbon take-up roll 9. The recording medium 14 is conveyed by the driving roller 15 and the driven roller 16 by the driving of the motor 13, and is then positioned between the platen 4 and the pinch roller 17, and further conveyed and the leading edge is detected by the sensor 29 to be positioned at a predetermined print position. To be done. The cam 6 of the thermal head drive device rotates in the clockwise direction by driving a motor (not shown), and the tension of the spring 5 causes the thermal head support member 24 to swing and the thermal head 3 to start approaching the platen 4.

From this state, as shown in FIG. 2, when the cam 6 continues to rotate in the clockwise direction and the thermal head 3 is in pressure contact with the recording medium 14, the claw portion 25c of the stop claw 25 and the teeth of the ratchet wheel 28 are connected. The meshing is released and the ink ribbon 7 is ready to be fed. As in the conventional example, the motor 1
The thermal printing is sequentially performed as the platen 4 is rotated by the driving of 3.

When the recording medium 14 is conveyed again after printing is completed, the cam 6 rotates in the counterclockwise direction,
The thermal head 3 is separated from the recording medium 14 along the platen 4 together with the thermal head support member 1. In conjunction with the operation of the thermal head support member 1, a means for restraining the rotation of the ink ribbon take-up roll 9, that is, the claw portion 25c of the stopping claw 25 and the teeth of the ratchet wheel 28 mesh with each other, and the motor 13 is driven. , Ink ribbon winding roll 9
Is stopped. At this time, since the ink ribbon take-up roll 9 is provided with the torque limiter 9a,
Even if the winding of the ink ribbon 7 is restricted, only the recording medium 14 is reliably conveyed.

FIG. 3 shows a schematic thermal printer 31.
FIG. 1 is a general view of the printer 31.
An input unit 33 using a keyboard and a printing unit 34 for printing characters and the like on a tube and a label tape are integrated, and a label tape cassette 35 and an ink ribbon cassette 36 are detachable. Further, by removing the label tape cassette 36 and inserting the tube in its place, it is possible to print on the tube. 41 is a tube insertion port, 42 is a means for half-cutting the printed tube and label tape, and 43 is a means for all-cutting. Although not shown, by adding another cam integrated with the cam 6 and engaging the means 42 for half-cutting the added cam,
The thermal head drive and the half cut can be synchronized.

[0016]

As described above, in the thermal printer in which the conveyance of the recording medium and the winding of the ink ribbon are driven by the same motor, the thermal head is used after the printing or during the space (margin) creating operation. At the time of non-printing away from the recording medium along with the support member along the platen, the means for restraining the rotation of the ink ribbon take-up roll is driven in conjunction with the operation of the thermal head driving means, so that the take-up roll is completely fixed. Since only the recording medium is conveyed, waste of the ink ribbon due to idling is eliminated, and the ink ribbon becomes much more economical than the conventional one. At this time, since the ink ribbon take-up roll is provided with the torque limiter, even if the take-up of the ink ribbon 7 is restricted, the ink ribbon is not hindered and only the recording medium is reliably conveyed. Further, when the ink ribbon supply roll is constrained, the thermal head pulls the ink ribbon toward the platen at the start of printing, so that the ink ribbon on the used side of the take-up roll is conveyed backward, which impairs print quality. Since the ink ribbon take-up roll is restrained, a new ink ribbon is supplied from the side of the ink ribbon supply roll, so that print quality is not hindered.

[Brief description of drawings]

FIG. 1 is a plan view of the thermal printer of the present invention in which winding of an ink ribbon is restricted.

FIG. 2 is a plan view when releasing the constraint of the ink ribbon winding and performing thermal printing.

FIG. 3 is a schematic plan view of the entire thermal printer.

FIG. 4 is a plan view when winding a conventional ink ribbon.

[Explanation of symbols]

 3 Thermal Head 4 Platen 6 Cam 7 Ink Ribbon 9 Ink Ribbon Winding Roll 9a Torque Limiter 13 Motor 14 Recording Medium 24 Thermal Head Support Member 25 Stop Claw 28 Gear (Ratchet Wheel) 31 Thermal Printer

Claims (1)

[Claims] 1. A thermal printer in which a recording medium is conveyed and an ink ribbon is wound by the same motor, and a torque limiter is provided on an ink ribbon winding roll. A thermal head supporting member for supporting the opposing thermal head and a thermal head driving means for moving the thermal head supporting member to bring the thermal head closer to the platen are provided, and the thermal head supporting member for separating the thermal head from the platen when not printing. A thermal printer characterized in that the means for restraining the rotation of the ink ribbon take-up roll is driven in synchronism with the operation of the thermal head driving means when moving the printer.