JPS60210468A - Thermal printer - Google Patents

Abstract

PURPOSE:To eliminate deviation in the printing position at the boarder when one line is printed being divided into printing areas with a plurality of thermal heads by arranging the printing position of each thermal head to be correctable freely. CONSTITUTION:For example when there is a vertical deviation by a fixed amount l1 at the border C between the first and second half printing areas A and B of one line, by operating a screw rod 222 of a fine sdjusting mechanism 22, a mark 25 given on the side rim of the heads of thermal heads 17 and 18 is matched with the same position on a graduation 28 given at a fixed interval along the side rim of the heads of a tilting members 20 and 21 or one is matched with the other made as reference. When the printing pitch l2 is deviated at the border C, a driving gear 215 for a screw rod 213 of a fine adjusting mechanism 23 is turned to match a mark 24 given at the top end of the head of the respective thermal heads 17 and 18 with the graduation at the same distance L1 from the reference point of a plate body 26.

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 made so that the same line could be printed using two thermal heads, and the printing time for one line was reduced to 1/2 without changing the printing speed. There was a known method that enabled this, but it had the following secondary problems.

■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]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal printer that eliminates misalignment of printing positions at boundaries when printing the same line using a plurality of thermal heads in separate print areas.

[Structure of the invention]

The present invention is a thermal printer in which the same line can be printed by a plurality of thermal heads, and is configured so that the printing position of each thermal head can be freely corrected.

〔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 10 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, and is moored to a timing belt 7 stretched between a driving wheel 6 and a driven wheel 6'. ing.

Reference numeral 8 indicates a cassette which 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 second 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 core 9.9' of the ink ribbons a and b is a winding shaft 12.1 that projects the cassette 8 onto the upper surface of the carriage 4.
The nine take-up shafts 12 and 12', which can be integrally rotatably connected to the winder 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 a pinion 15.15'.
150', and when the carriage 4 moves forward (rightward in the figure), it follows the rotation of the pinion 15.15' and engages with the drive gear 13.13', transmitting nine 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'. Furthermore, even when the carriage 4 is moving back and forth, the intermediate gear 16.16' is a plunger of a solenoid 19.19' that operates the thermal head 17.18, which will be described later, when it is not pressed toward the platen 1. It is pushed by the rear end of the drive gear 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 FIG.
．． It is detachably attached to 21. The heating element attached portions of the thermal heads 17 and 18 are located in the recesses 11 and 1 of the cassette 8.
1' and.

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 operated upon receiving an electric signal such as character information, and presses the thermal head 17.18 against the platen 1 when tilted. The ink ribbons a and b are brought into close contact with the recording paper on the platen 1 by the pressure of the thermal heads 17 and 18, 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.
is now in charge.

6-22.23 move the thermal heads 17.18 up and down, which are responsible for the printing areas in the first and second half of one line.

Since the fine adjustment mechanisms 22 and 23, which are fine adjustment mechanisms for fine adjustment left and right, are common to both thermal heads, only the thermal head 18 side is shown in detail in FIGS. 3 and 4. The left and right fine adjustment mechanism 23 includes a tilting member 21. U-shaped frame 210 and bearing member 211 of carriage 4
is inserted with the pin 212, and 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.

Note that the forward and reverse rotation of the screw rod 213 is as shown in the figure.
A gear 214 is fixed to one end, a drive gear 215 that meshes with the gear 214 is pivotally supported on the side of the carriage 4, and the upper end of the drive gear 215 is made to protrude from the upper surface of the carriage 4, so that it can be easily operated manually at any time. Reference numeral 216 in Figure 1 is a locking member that can be operated.

The vertical fine adjustment mechanism 22 also has a gate-shaped receiving member 218 on the back surface of the tilting member 21, which has two arm pieces 217 that can hold both shoulders and both ends of the lower edge of the thermal head 18 on the front surface of the tilting member 21. The tips of two threaded rods 222, which are provided to be movable up and down and are screwed into the rear protrusion 219 of the receiving member 218, are brought into contact with the upper surface of the rear protrusion 220 of the tilting member 21, and between the nine protrusions 219 and 220. It is formed by screwing in a screw rod 221. That is, the thermal head 18 is slightly moved in the vertical direction by removing the screw rod 221 and rotating the screw rod 222 forward and backward. After adjustment using the threaded rod 222, the position of the receiving member 218 can be fixed using the screw 221.

24 is a mark marked on the top end of the head of the thermal head 17, 18, and 25 is a mark marked on the side end of the head. Mark 2
Reference numeral 4 indicates a scale 27 that is graduated at regular intervals along the upper edge of a plate 26 that is erected on the cover of the carriage 4 so as to face the thermal head 17. This serves as an indicator for a scale 28 marked at regular intervals along the side edge of the section (see Fig. 6).

Note that only one of the fine adjustment mechanisms 22 and 23 may be employed. In addition, if there is an appropriate means other than the above (other mechanical means or electrical means), it may be possible to use it. The adjustment may be done by electrical means, or may be done both vertically and horizontally.

Next, the operation of the above embodiment will be explained.

When the same line is printed by the thermal heads 17 and 18, the printing position of each thermal head is, for example, vertically at the boundary C between the printing areas A and B in the first and second half of the - line, as shown in Figure 7. When the deviation is a certain amount of Nl, operate the screw rod 222 of the fine adjustment mechanism 22 to move the mark 25 marked on the side edge of the head of each thermal head 17, 18 to the tilting member 2.
Do you match it to the same position on the scale 28 marked at regular intervals along the side edge of the head of 0.21?

9- It is done by taking one as a reference and adjusting the other to it. Also, in the boundary portion C.

When the printing pitch 12 is out of order, the threaded rod 213 of the fine adjustment mechanism 23 is operated by rotating the drive gear 215. In this case, since the distance S between the reference points of the plate 26, which is erected on the cover of the carriage 4 facing each thermal head 17, 18 and has scales 27 marked at regular intervals along the upper edge, is constant. , each thermal head 17°18
The mark 24 marked on the top of the head of the plate 26 is aligned with the scale located at the same distance L1 from the reference point of the plate body 26.

〔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 the present invention is characterized by the provision of an adjustment mechanism for adjusting the position of each thermal head, it is possible to easily correct deviations in printing position at the boundaries of printing areas due to variations in component accuracy of each head. Therefore, it is possible to improve printing quality.

Further, in the present invention, when each thermal head and its opposing member are provided with marks and scales, various excellent effects such as easier adjustment can be achieved.

[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 perspective view showing the fine adjustment mechanism of the thermal head, Fig. 4 is an exploded perspective view of the same, Fig. 5 is a partial sectional view of the same side, and Fig. 6
The figure is a perspective view showing marks and scales, and FIG. 7 is a view showing a printing area. 1-Platen 2-Recording paper 4-Carriage 8-Cassette 17, I8-Thermal head 20, 21-Tilt member 2
2.23-Fine adjustment mechanism 213.217-screw rod 214--receiving member ^, B-printing area C-border a, b-ink ribbon 11 = Fig. 1 Fig. 2

Claims (2)

[Claims] (1) In a thermal printer that can print the same line using multiple thermal heads. A thermal printer comprising an adjustment mechanism for adjusting the position of each thermal head. (2) The thermal printer according to claim 1, wherein each thermal head and its opposing member are marked.