JPS60210467A - Thermal printer - Google Patents

Abstract

PURPOSE:To eliminate deviation in the printing position at the border upon printing the printing area dividedly by allowing other thermal heads to be corrected freely in the printing position with at least one thermal head as reference. CONSTITUTION:A thermal head 17 handles the first half of an area in the printing operation while a thermal head 18 the latter half thereof. A horizontal fine adjusting mechanism 23 for fine adjusting the thermal head 18 vertically and horizontally has a tilting member 21 tilting on a pin 212 while finely moving horizontally with the forward or backward turn of a screw rod 213. A vertical fine adjusting mechanism 22 finely moves vertically by turning a screw rod 218 forward or backward with a screw rod 217 drawn out. When there is a vertical deviation by a fixed amount l1 at the border C between the printing areas A and B, respectively corresponding to first and second halves of one line, adjustment can be done by turning the screw rod 218 forward or backward while to adjust deviation in the printing pitch l2 at the border C, the screw rod 213 is turned likewise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal printer capable of printing the same line using a plurality of thermal heads.

[Conventional technology]

Generally, a thermal printer has a thermal head mounted on a carriage that moves in a direction perpendicular to the feeding direction of the recording paper, and as the carriage moves, the thermal head is tilted by an electric signal to press the ink ribbon onto the recording paper.
Printing is performed by selectively applying voltage to heating elements arranged on the head surface, and if this printing operation is performed with one thermal head, it takes a lot of time to print. -In order to increase the printing speed of the thermal head, it is possible to increase the power applied to the heating element on the head surface or to lengthen the applied pulse width, but this is not recommended as it may shorten the life of the head. do not have.

Therefore, as described in Japanese Patent Application Laid-Open No. 55-156080, a configuration was used in which the same line could be printed using two thermal heads, and the printing time for one line was 1/2 without changing the printing speed.
There was a known method that could shorten the number to /2, but it had the following first-order problem.

■Due to variations in the precision of parts of each head, there was a risk that the printing position would shift vertically and horizontally at the boundaries of the printing area, resulting in a decline in printing quality.

■Since the mechanism for crimping and releasing each thermal head from the platen is common, even if you want to print with only one thermal head, all heads will be crimped to the platen.
The head wore quickly, shortening its lifespan, and fogging occurred due to rubbing of the ink ribbon.

- Since the ink ribbon is common to each thermal head, the ink ribbon is wound up even when it is desired to print with only one thermal head, resulting in wasted ink ribbon.

[Purpose of the invention]

This invention eliminates misalignment of printing positions at boundaries when printing the same line using multiple thermal heads in separate print areas, and also reduces the lifespan of the thermal heads and wastes ink ribbon. The purpose of the present invention is to provide a thermal printer that does not cause any damage.

[Structure of the invention]

The present invention is a thermal printer capable of printing the same line with a plurality of thermal heads, which is configured so that the printing position of other thermal heads can be freely corrected with reference to at least one of the thermal heads. .

〔Example〕

Next, the present invention will be described based on embodiments shown in the accompanying drawings.

In the figure, reference numeral 1 indicates a platen, and a recording paper 2 is pressed against the surface of the platen 1 by a presser roll 3. A carriage 4 runs along the axial direction of the platen 1, and is slidably supported by a guide shaft 5.
It is moored to a timing belt 7 stretched between a driving wheel 6 and a driven wheel 6'.

8 indicates a cassette that is detachably attached to the upper surface of the carriage 4 and houses two sets of ink ribbons a and b;
Both ends of the ink ribbons a and b in the cassette 8 are hung on the original winding core 9.9' and the first winding core 10.10', respectively, and the intermediate portions are formed in recesses 11 provided at symmetrical positions on one side of the cassette 8. , 11' are exposed to the outside through through holes on both sides. The winding cores 9 and 9' of the ink ribbons a and b are the winding shafts 12.1 that project the cassette 8 onto the upper surface of the carriage 4.
The six take-up shafts 12 and 12', which can be integrally rotatably connected to the winding roller 2', are each independently driven in conjunction with the travel of the carriage 4. The driving means is not particularly limited, but in the example shown in the second figure, a driving gear 13.13' is fixed to the lower end of the winding shaft 12.12', and the driving gear 13.13' is connected to the traveling path of the carriage 4. It is connected via an intermediate gear 16.16' to a pinion 15.15' that meshes with a rack 14 attached in parallel. This intermediate gear 16.16' is connected to a lever 150. which rotates around the axis of the pinion 15, 15'.
150', and when the carriage 4 moves forward (rightward in the figure), =5- follows the rotation of the pinion 15.15' and the drive gear 13
．． It meshes with 13' and transmits two rotations.

Conversely, when the carriage 4 returns, it is urged to rotate in the direction of the arrow by the pinion 15.degree. 15', and is separated from the drive gear 13, 13'. Further, even when the carriage 4 is moving back and forth, the intermediate gear 16.16' is connected to the rear end of the plunger of a solenoid 19.19' that operates the thermal head 17.18, which will be described later, when the thermal head 17.18 is not pressed toward the platen l side. It is pushed by and separated from the drive gear.

The thermal heads 17 and 18 include a tilting member 20 whose lower end is pivotally connected to the surface of the carriage 4 facing the platen, as shown in the third figure.
．． It is detachably attached to 21. Thermal head 17.18 (7) QJ% body attachment part is recess 1 of cassette 8
1,11'.

It is inserted between the ink ribbons a and b. The tilting member 20.21 is tilted independently by a plunger of a solenoid 19.19' which is actuated upon receiving an electric signal such as character information, and presses the thermal head 17.18 against the platen 1 when tilted. By pressing this thermal head 17.18, the ink ribbon a,
b is brought into close contact with the recording paper on the platen 1, and printing is performed by the heat generated by the heating elements of the respective thermal heads 17 and 18. In this printing operation, the thermal head 17 is in charge of the first half of the same line, and the thermal head 18 is in charge of the second half.

Reference numerals 22 and 23 indicate fine adjustment mechanisms for finely adjusting the thermal head 18, which is responsible for the printing area in the latter half of one line, vertically and horizontally.The fine adjustment mechanisms 22 and 23 are detailed in FIGS. 4 and 5. It is shown. The left and right fine adjustment mechanism 23 includes a tilting member 21. U-shaped frame 210 and bearing member 211 of carriage 4
Insert the pin 212 into the U-shaped frame 210. A threaded rod 213 is screwed into the bearing member 211 of the carriage 4. That is,
The tilting member 21 tilts around the bin 212, and
It is designed to move slightly from side to side by rotating the screw rod 213 in the forward and reverse directions.

In addition, the vertical fine adjustment mechanism 22 includes a receiving member 214 for the thermal head 18 on the tilting member 21, and the tips of two threaded rods 21B screwed into the protrusion 215 of the receiving member 214 are connected to the protrusion 216 of the tilting member 21. It abuts against the upper surface and a threaded rod 217 is screwed between both protrusions 215 and 216. That is, the thermal head 18 is slightly moved in the vertical direction by removing the screw rod 217 and rotating the screw rod 218 forward and backward. After this adjustment using the screw rod 218, the position of the receiving member 214 can be fixed using the screw rod 217.

Said! l [Adjustment mechanisms 22 and 23 are used, for example, as shown in FIG.

If the boundary C of B is shifted by a certain amount z1 in the vertical direction, adjust the screw rod 217, and if the printing pinch 12 is incorrect at the boundary C, adjust the screw rod 213 by rotating it in the forward or reverse direction. I'm trying to make it possible.

Note that there are cases where only one of the fine adjustment mechanisms 22 and 23 is employed. In addition, if there is an appropriate means (other mechanical means or electrical means) other than the above, it may be used. In other words, the thermal head may be adjusted either vertically or horizontally by mechanical means. Adjustment in other directions may be done by electrical means, or may be done both vertically and horizontally. - Figure 7 shows a second embodiment, in which cassettes 8 and 8', each housing ink ribbons a and b separately, are removably mounted on a carriage 4, and a single winding mechanism is used. The thermal head mounting mechanism and the thermal head fine adjustment mechanism on the cassette 8' side can be constructed in the same manner as in the first embodiment.

〔Effect of the invention〕

As described above, the present invention provides a thermal printer capable of printing the same line using multiple thermal heads.
Since at least one of the plurality of thermal heads is fixed and the other thermal heads can be finely adjusted vertically and horizontally, it is possible to prevent the printing position at the boundary of the printing area due to variations in component accuracy of each head. Problems can be easily corrected. Therefore, it is possible to improve printing quality.

Furthermore, in the present invention, when the mechanism for pressing on and releasing the pressure from the platen is made independent for each thermal head, it is possible to print with only one thermal head, and in this case, the other heads may be separated from the platen. This not only prevents the inactive heads from being worn out and extends their lifespan, but also allows the ink ribbon supplied to each thermal head to run using its own winding mechanism, allowing the inactive thermal heads to The ink ribbon is not wound up and has various excellent effects such as not wasting the ink ribbon.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a first embodiment of the invention, and FIG. 2 is a schematic plan view of the inside of the carriage. FIG. 3 is a side sectional view of the tilting member attachment part of the thermal head, and FIG. 4 is a perspective view showing the fine adjustment mechanism of the thermal head.
FIG. 5 is an exploded perspective view, FIG. 6-10 is a diagram showing the printing area, and FIG. 7 is a plan view showing the second embodiment. 1-Platen 2--Recording paper 4-Carriage 8-Cassette 17.18-Thermal head 20.21-Tilt member 2
2.23-・-Fine adjustment mechanism 213.217- Screw rod 214-Receiving member A, B・-
Printing area c - Boundaries a, b - Ink ribbon patent Applicant Konishi Roku Photo Industry Co., Ltd. 2

Claims (1)

[Claims] (11) A thermal printer capable of printing the same line with a plurality of thermal heads. At least one of the plurality of thermal heads is fixed, and the other thermal heads are arranged vertically and/or horizontally. A thermal printer according to claim 1, characterized in that the thermal printer is provided so as to be finely adjustable. (2) The thermal printer according to claim 1, wherein each of the thermal heads has an independent mechanism for pressing and releasing the pressure on the platen. The thermal printer according to claim 1 or 2, wherein each thermal head is provided with an ink ribbon winding mechanism.