JPS6328664A - Printer - Google Patents

Abstract

PURPOSE:To simplify an entire configuration and improve a printing rate by mounting one set of thermal head and ink ribbon cassette for printing action on a carriage when it moves in a forward travel and another set of the same components for printing action when the carriage moves in a backward travel along the axial direction of a platen. CONSTITUTION:When a carriage 3 moves in a forward travel, one set of thermal head 7 and ink ribbon cassette 9 perform a printing. On the other hand, when the carriage moves in a backward travel, another set of thermal head 8 and ink ribbon cassette 10 do the same job. In this case, two ink ribbon cassettes 9, 10, arranged along the axial direction of a platen 1, do not have to be moved in a forward and a backward carriage travel as does those of a conventional printer. Therefore, the selection of a printing direction can be made smoothly, thus improving a printing speed rate. Further, a cassette elevator mechanism for the vertical movement of an ink ribbon cassette is not required, contributing to the simplification of the entire configuration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called serial type printer that prints while moving a carriage carrying a thermal head and an ink ribbon in the axial direction of a platen. This invention relates to a printer that is capable of printing not only when moving but also when moving backwards.

In the L-pulling J and JL serial printers, printing is performed both during forward and backward movement of the carriage (hereinafter referred to as bidirectional printing).

) is extremely convenient as it leads to a significant improvement in printing speed.

However, serial type printers press the thermal head against the platen with the relative speed to the recording paper reduced to zero by winding the ink ribbon in the opposite direction to the carriage movement speed at a speed equal to the carriage movement speed. Since this is a device that performs printing, if you try to print while the carriage is moving backwards, you have to wind up the ink ribbon in the opposite direction to when the carriage is moving forward, and the ink ribbon used for printing during the forward movement must be wound up. The print quality deteriorates dramatically as the area has to be used again.

Therefore, conventionally, as seen in Japanese Patent Application Laid-Open No. 59-218887, ink ribbon cassettes are stacked in two layers, upper and lower, and both ink ribbon cassettes are moved upward or downward by one ink ribbon cassette when the carriage moves forward and backward. This enables bidirectional printing without deteriorating printing quality by switching and using the printer.

However, according to the above-mentioned conventional technology, two ink ribbon cassettes are stacked one on top of the other, so in order to switch between use when the carriage moves forward and back, the cassette must be moved up and down. An electric heater mechanism is required, and the structure on the carriage is complicated and expensive, and a moving space equivalent to one cassette is required as a dead space above or below, and when changing the direction of carriage movement. The disadvantage is that the cassette must be moved upward or downward, which requires time, and the printing speed is reduced accordingly.

An object of the present invention is to provide a useful printer that can perform bidirectional printing without causing such problems.

In order to achieve the above object, the present invention includes a set of a thermal head and an ink ribbon cassette, which perform a printing operation when the carriage moves forward, on a carriage that reciprocates in the axial direction of the platen. , a set of a thermal head 8 and an ink ribbon cassette, which perform a printing operation when the carriage moves backward, is mounted and arranged along the axial direction of the platen.

Operation According to the above configuration, printing can be performed using one set of thermal head and ink ribbon cassette when the carriage is moving forward, and printing can be performed using the other set of thermal head and ink ribbon cassette during forward movement.

In this case, since the two ink ribbon cassettes are arranged along the axial direction of the platen, there is no need to move the ink ribbon cassettes when the carriage moves forward and backward, unlike in the conventional case. Switching can be done smoothly and printing speed can be improved.

Figure 1 shows a schematic diagram of a printer as an embodiment of the present invention, where ■ is a platen around which the recording paper 2 is wound, and the carriage 3 is moved forward by a line feed means (not shown). Or, it is intermittently rotated in the sub-scanning direction P every time it moves backward. The carriage 3 is slidably supported by two shafts 4.5 installed in the axial direction of the platen 1, and is driven via a timing heald 6 by forward and reverse rotation of a pulse motor (not shown) to reciprocate. Two sets of thermal heads 7.8 and ink ribbon cassettes 9 and 10 are mounted on the carriage 3 along the axial direction of the platen 1.

When the ink ribbon cassette 9.10 is mounted on the carriage 3, the take-up reel 12 and supply reel 13 are placed in a rectangular cassette case 11 in a direction perpendicular to the axial direction of the platen, as shown in FIG. 2.3. It has a so-called vertical structure. By adopting such a vertical structure, two ink ribbon cassettes 9 can be stored in a small space.
, 10 can be arranged. A black ink ribbon 14 is wound between the take-up reel 12 and the supply reel 13 via a plurality of rollers 15 . . . and a thermal head 7 or 8. In addition, thermal head 7 (8
) The portion of the cassette case 11 at which the ink ribbon 14 is wound is cut out as shown by 16.

2 sets of ink ribbon cassettes9. The one on the left side 9 is a cassette used for printing when the carriage moves forward, and the one on the right side 10 is a cassette used for printing when the carriage moves forward. Both 9 and 10 have symmetrical structures. There is. Usually, cassettes with the same structure are used, with 9 facing up on one side and 10 facing up on the other.
Use it face down.

Each ink ribbon cassette 9.10 has a carry.

When the take-up reel 1 is mounted on the reel 3,
2 is a drive shaft 17.1 projecting upward from the carriage 3.
8. The supply reel 13 is connected to a rotatable shaft (not shown) protruding from the carriage. The lower end of the drive shaft 17.18 is fixed within the carriage to a gear 19.20 with a one-way clutch 19a and 2Oa, as shown in FIG. 4.5.

Each gear 19, 20 meshes with a gear 22 attached to the shaft of a single rotary drive source 21, such as a motor, capable of forward and reverse rotation. When the rotary drive fQ21 is rotated in the C direction by the action of the one-way clutches 19a and 20a, one of the drive shafts 17
When the rotary drive source 21 is rotated in the d direction, only the other drive shaft 18 is driven in the b direction. The rotation drive source 21 is controlled by a control circuit (not shown) so that it rotates in the C direction when the carriage 3 moves forward and in the d direction when the carriage moves backward. The ink ribbon in the left cassette 9 is wound up in the direction of arrow A, and when the carriage 3 moves back, the ink ribbon in the right cassette 10 is taken up in the direction of arrow B.
It will be wound in the direction.

The thermal head 7.8 is mounted on a carriage so as to be freely movable in the direction toward and away from the platen, similar to the mounting structure in known printers, and is biased by a spring 25 in a direction away from the platen 1. A mechanism for press-contacting the platen 1 is provided behind each thermal head 7.8, but in this embodiment, a single press-contact driving mechanism 26 is used to connect the two thermal heads to the nozzle 7.
．． 8 are pressed against each other alternately when the carriage moves forward and when it moves backward. This single pressure contact drive mechanism 26
．． As shown in Figure 3, a pinion 27 attached to a forward/reverse motor, etc., and two ranks 2 that mesh with the pinion 27.
8.29. The forward and backward movement of each rank 28 and 29 is guided and regulated by a rank guide 30 and a guide bin 31. Here, forward movement means a direction approaching the platen, and backward movement means a direction away from the platen. One rank 28 is located behind one of the thermal heads 7, the other rack 29 is located behind the other thermal head 8, and one of the ranks 28 is located behind the other thermal head 8 with respect to the pinion 21 as shown in the figure.
When (29) is in the forward position, the other (29) (28) is in the retracted position and meshes with each other. Therefore, by rotating the motor in the forward direction for printing when the carriage 3 moves forward, and in the reverse direction for printing when the carriage 3 moves backward, the two thermal heads 7
8 can be alternately pressed against the platen 1 when the carriage 3 moves forward and backward as described above.

According to the above configuration, when the carriage 3 moves forward, the rotary drive rA21 is rotated in the C direction to generate the ink ribbon cassette 9.
With the relative speed of the side ink film and the recording paper wound around the platen 1 set to zero, the head pressure contact drive mechanism 26 is driven to press the thermal head 7 against the platen to perform printing.

On the other hand, when the carriage 3 moves backward, the rotational drive source 21 is
With the ink film on the ink ribbon cassette 10 side being rotated in the direction B and the ink film on the ink ribbon cassette 10 side being wound in the direction B, the relative speed with respect to the recording paper is reduced to zero, the head pressure contact drive mechanism 26 is driven to press the thermal head 8 against the platen for printing. I do.

Thus, bidirectional printing is possible.

In this case, the print start position when the carriage moves forward is
When the carriage is at the left end of the platen as shown in Fig. 2, set the thermal head 8 on the right side or a position to the right of it, and when the carriage moves backward, the printing start position is set as shown in Fig. 3. Carriage 3 is placed on the right edge of the platen.
If the position is set to the position of the left thermal head 7 when , or a position to the left thereof, the left end and right end of each line on the recording paper will be aligned.

In addition to the head pressure contact drive mechanism 26 shown in FIG. 2, for example, as shown in FIG. 6(a), eccentric cams 35, 3
6 can also be used. Eccentric cams 35 and 36 in the diagram
are attached to the shaft 37 with a phase difference of 180 degrees, and each time the shaft 37 makes a half rotation, one of the cams comes into contact with the thermal head 7 or 8 and is pressed against the platen. The illustrated state shows that the thermal head 8 is in pressure contact with the platen. The shaft 37 is connected via a one-way clutch 38 to a lever 40 that swings depending on whether a solenoid 39 is energized or de-energized. When the solenoid 39 is energized, the lever 40 swings in the direction of the arrow mark, and the cams 35 and 36 accordingly rotate in the direction of the arrow M. solenoid 39
When the lever 40 is de-energized, the lever 40 swings in the opposite direction to the L direction, but the shaft 37 and the cams 35 and 36 do not rotate due to the action of the one-way clutch 38. Therefore, solenoid 39
By repeatedly controlling energization and de-energization, the thermal heads 7.8 can be alternately pressed against the platen. 4゜ again,
The eccentric cam that alternately presses the head against the platen is shown in Figure (b).
As shown in 41.42, it may be attached to a driven gear 44.45 that meshes with the drive gear 43. In the figure, 46 is a motor that rotationally drives the drive gear 43.

Nuwoq (7) Bujikou As explained above, according to the present invention, there are two
Since the set of thermal head 8 and ink ribbon cassette are mounted in the axial direction of the platen, bidirectional printing is possible by selectively using each set of thermal head 8 and ink ribbon cassette when the carriage moves forward and backward. At the same time, the ink ribbon cassette does not have to be moved up and down like in the past (but can remain mounted and fixed on the carriage, so the overall configuration is simplified as there is no need for a cassette elevator mechanism, etc.). It has many advantages, such as increasing the printing speed by not having to move the cassette, and eliminating the need for dead space for moving the cassette.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view of a printer as an embodiment of the present invention, Fig. 2 is a plan view showing the state when the carriage is moving forward, Fig. 3 is a plan view showing the state when the carriage is moving backward, and Fig. 4 is an ink ribbon. 5 is a side view thereof, and FIG. 6 (al (bl) is a diagram showing other possible configurations as the head pressure contact drive mechanism, respectively. 1. ...Platen, 3...Carriage, 7.8...
Thermal head8. 9.10... Ink ribbon cassette. Figure 1 Figure 4 Figure 5 Figure 2 Figure 3 Figure 6 (G) Figure 6 (b)

Claims (4)

[Claims] (1) Two sets of thermal heads and ink ribbon cassettes are mounted along the axial direction of the platen on a carriage that reciprocates in the axial direction of the platen, and each set of thermal heads is moved when the carriage moves forward and backward. A printer equipped with a pressure drive mechanism that alternately presses against the platen. (2) Claim (1) characterized in that the pressure contact drive mechanism is shared by the two sets of thermal heads.
Printers listed in section. (3) Each set of ink ribbon cassettes is connected to a single rotary drive source via a one-way clutch, and the direction of rotation of the rotary drive source is switched between forward and reverse when the carriage moves forward and backward. The printer according to claim 1 or 2, wherein the printer is configured to alternately wind up sets of ink ribbons. (4) Claims (1) to (3) characterized in that the ink ribbon cassette has a vertical structure in which a take-up reel and a supply reel are arranged in a direction perpendicular to the moving direction of the carriage. ) Printer listed in any of the above.