JPH0115386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a line printer using a dot print head.

A line printer using dot print heads, in which multiple print heads are arranged in parallel at equal intervals in the width direction of the print medium, and dot printing is performed while the print head carrier is moved in the width direction of the print medium. is proposed. The present invention is aimed at increasing the printing speed of such a dot line printer, suppressing vibrations occurring during printing operations, and improving the visibility of printing. A detailed explanation will be given below with reference to the drawings.

1 to 3 show one embodiment of the present invention, in which 1 carries a plurality of print heads 2 at equal intervals in the width direction of print paper 3, that is, in a direction parallel to the central axis of platen 4. A first carriage bar 5 is a second carriage bar that carries the same plurality of print heads 6 at regular intervals in the direction, and these two carriage bars 1 and 5 are arranged along guide shafts 7 and 8 provided parallel to the platen 4. It is supported so that it can be moved back and forth. The print heads 2 and 6 on the two carriage bars are held equidistant from each other from the central axis of the platen 4, and the distance between them along the outer circumference of the platen is an odd multiple of the line pitch. . In this embodiment, the central axes of the print heads 2 and 6 are arranged to be orthogonal to each other, but the arrangement is not limited to this arrangement.

As shown in FIG. 3, a timing belt 9 is looped between the drive pulley 11a and the pulley 11b of the motor 10, and is moved parallel to the platen 4 as the motor 10 rotates. This timing belt 9 is mounted parallel to the platen 4, and has leg portions 1a and 5a extending from the bottom of each of the first and second carriage bars 1 and 5 by clamp means 12 and 13 at a part thereof.
These joints move in opposite directions when the timing belt 9 runs. Further, the distance between the driving pulley 11a and the pulley 11b is sufficiently longer than the reciprocating stroke of the first carriage bar 1 and the second carriage bar 5. Reference numeral 14 denotes a tractor that feeds the print paper 3 between the two print head rows and the outer periphery of the platen.

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

When the motor 10 rotates in the direction of arrow A in FIG. 2, the first carriage bar 1 connected to the timing belt 9 moves in the direction of mark B, and the second carriage bar 5 moves in the opposite direction of arrow C. When the motor 10 reverses, the first carriage bar 1
rotates in the direction of arrow C, and the second carriage bar 5
moves in the direction of arrow B. The motor 10 has a connecting portion between the first carriage bar 1 and the second carriage bar 5 and the timing belt 9, which is connected to the pulleys 11a and 1.
The direction of rotation is switched before reaching 1b. That is, by rotating the motor 10 alternately by a predetermined amount in the forward and reverse directions, the first carriage bar 1 and the second carriage bar 5 are alternately moved in the directions of arrows B and C, resulting in reciprocating motion over a fixed section. 1st
Since the carriage bar 1 and the second carriage bar 5 are equipped with a plurality of printing heads as described above, they have a considerable mass. For this reason, it is expected that vibrations will occur due to the reciprocating motion, but since the directions of movement of the first and second carriage bars 1 and 5 are opposite to each other at the same time, the vibrations that would otherwise occur due to this motion are canceled out by each other. Ru. As a result, the occurrence of vibrations in the printer as a whole is suppressed.

The printing operation is performed while the carriage bars 1 and 5 are reciprocating. The print heads 2 and 6 have a single print element, for example a print pin, which is selectively driven during the movement of the carriage bars 1 and 5, so that one print head prints multiple prints on the same line. A dot is printed. The printing of the dot pattern 2 of characters, symbols, etc. is carried out using this operation as a main scanning and the feeding operation of the printing paper 4 as a sub-scanning, whereby a plurality of dots such as characters, symbols, etc. are printed in a matrix at the same time.

This printing operation has two operation modes depending on the above configuration. That is, since two rows of print heads are provided, there is a first operation mode in which printing is performed using these two print head rows, and a second operation mode in which printing is performed using only one of the print head rows.

In the first operating mode, for example, the print head column on the second carriage bar 5 prints odd-numbered lines, and the print head column on the first carriage bar 1 prints even-numbered lines. Lines of the printing paper 3 are fed at two-line pitches. FIG. 4 shows an example of printing in this mode of operation.As mentioned above, the distance along the outer periphery of the platen 4 between the two print head rows is an odd multiple of the row pitch P. When the print head rows of the first carriage bar 1 are opposite the fifth row, the print head rows of the first carriage bar 1 are opposite the second row. If a line break is made at a two-line pitch 2P, the even numbered rows will always be opposed to the print head columns of the first carriage bar 1, and the odd numbered rows will be opposed to the print head columns of the second carriage bar 5. As a result, for example, the 2nd, 4th, .
...The (2n-1)th line will be printed by the print head 6 on the second carriage bar 5, and two lines will be printed at the same time. Therefore, high-speed printing is possible in this operating mode.

The second operation mode is suitable when the print data transfer speed is slow, and in particular, printing is performed only with the print head row on the first carriage bar 1 side so that the print information comes to a visible position quickly. In this case, the line feed pitch of the printing paper 3 is one line pitch. Switching from the first operation mode to the second operation mode may be performed manually, but it is also possible to use a control means that monitors the storage status of print data in the print data buffer and switches when the print data accumulation is low. May be provided.

In this embodiment, the printing heads 2 and 6 are equipped with a single printing element, but a printing head in which a plurality of printing elements are arranged in a direction perpendicular to the direction of movement of the carrier bar may also be used. .
When this print head is used, printing can be performed even faster.

In another embodiment, the print heads 2 and 6 are detachably attached to the carriage bars 1 and 5, and the number of print heads is changed, for example, from 8 to 4, depending on the print data transfer speed, printing speed, and paper width. The number of print heads may be selected as appropriate, and the reciprocating stroke of the carriage bars 1 and 5 may be lengthened depending on the number of print heads to provide flexibility in the performance of the printer. Such flexibility can be achieved by simply changing the amount of rotation of the motor, by connecting the carrier bar and the belt as described above, and transferring this belt by forward and reverse rotation of the motor to cause the carrier bar to reciprocate. Therefore, it can be carried very easily.

As explained above, according to the present invention, it is possible to prevent vibration of the printer during printing operation, and to achieve the effect of increasing printing speed, and when the transfer speed of print data is slow, emphasis is placed on the visibility of print data. This has the advantage that it can also be used to improve printing operations.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing essential parts of an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. The figure is a diagram showing an example of printing in the first operation mode. 1...First carriage bar, 2, 6...Print head, 3...Print paper, 4...Platen, 5...
2nd carriage bar, 7, 8...Guide shaft, 9...Timing belt, 10...Motor,
11a, 11b...drive pulley, 12, 13...
Clamping means.

Claims (1)

[Scope of Claims] 1. In a dot line printer that prints dots while reciprocating a print head carrier in which a plurality of print heads are attached at equal intervals in the width direction of a print medium in the width direction of the print medium, Two sets of print head supports arranged along the outer periphery are connected to respective belts mounted parallel to the platen and moving in opposite directions, and supported by the same guide shaft. 1. A dot line printer characterized in that a plurality of print heads attached to a dot line are arranged so that the driving directions of the print elements are orthogonal between each set. 2 The print heads attached to the two print head carriers are spaced apart along the outer periphery of the platen by an odd number of row pitches, with one set of print heads printing the odd number rows and the other set of print heads printing the even number rows. A dot line printer according to claim 1, which prints lines.