JPS60240473A - Printer apparatus - Google Patents

Abstract

PURPOSE:To eliminate variable density spots in printing generated between different printing heads, by setting different exciting times to a setting means and changing over the the same by a change-over indication means to impart different exciting times to a plurality of printing heads. CONSTITUTION:When density variation is generated in printing in a manufacturing process or a printing test in maintenance, an exciting time is changed over to a long exciting time t+ when low density printing is converted to high density one or changed over to a short one t- when high density printing is converted to low density one by changing over either one of change-over switches 20a, 20b. By this mechanism, the set exciting time of either one of exciting width control circuits 21a, 21b is changed over. The exciting width control circuits 21a, 21b excite printing heads 1a, 1b in different exciting times on the basis of the printing driving orders of printing control circuits 9a, 9b to apply printing driving to said heads. By this mechanism, density variation is adjusted by the change-over of the change-over switches 20a, 20b when there is left and right density variation in the printing by the printing heads 1a, 1b to eliminate the density variation in printing and printing quality can be enhanced.

Description

[Detailed description of the invention] [Industrial application field] The present invention can be applied to multiple printheads having multiple printheads.

The present invention relates to a RAD printer device, and more particularly to a multi-head printer device that can eliminate printing shading between print heads.

In recent years, serial printers such as wire tod printers have been developed and put into practical use as print output devices for various computer terminals and word processors. As one method, a multi-head printer has been developed which is equipped with a plurality of print heads, divides one line, and prints each part using each print head.

In this case, it is necessary that the shading of the prints printed by each print head be uniform.

[Conventional technology]

FIG. 2 is a perspective view illustrating the outline of a multi-head printer device, FIG. 3 is a side view showing a part of the print head of FIG. 2, and FIG. 4 is a control block diagram showing a conventional method.

As shown in FIG. 1, two print heads la and lb mounted on a carrier 4 face the platen 2 via a print paper 3 set on the platen 2. As shown in FIG. The printing paper 3 is transported in the direction of arrow A in the figure by a paper transport mechanism (not shown).

The carrier 4 is slidably fitted into a guide shaft 5 disposed parallel to the platen 1, and is also screwed into a feed screw 6 parallel to the platen 2. The feed screw 6 is connected to a motor via a pulley (not shown), and by rotating the motor forward and backward, the print heads la and lb are moved as indicated by arrows B in the figure.
It can be moved back and forth in the C direction.

When the printing head 1a is located at the left end of the printing paper 3 in the figure, the printing head lb is located approximately at the center of the printing paper 3, and each is on the left half of the center.

Shares the printing on the right half.

The print heads la, lti are composed of a plurality of print magnets having print wires, which will be described later, in order to form prints using dots.

That is, FIG. 2 shows the printing magnet 10 of the printing heads Ia and Ib, and the printing magnet 10 has a core 12 . Armachia 13 arranged so as to be in contact with the core 12. Printing wire 14 fixed to the tip of the armature 13 Drive spring 15 on which the armature 13 is elastically supported Magnetic path portions 16a to 16C9 Permanent magnet 17
．． A presser plate 18 that presses down the drive spring 15. and a wire guide 19 having a guide hole 19a for guiding the tip of the printing wire 14. An ink ribbon 7 is placed between the wire guide 19 and the printing paper 3.

Further, a block diagram of the drive control of the print heads la and lb is shown in FIG. It has a function of selectively exciting the IO for a predetermined period of time to perform a printing operation.

Since it has this semi-uniform configuration and function, the printing control circuit 8
When the print head 1a+Ib is activated by commands from a and 8b, when the print magnet 10 is energized so that the NS pole of the permanent magnet 17 and the pole of the core 12 are opposite, the core 12
acts as an electromagnet to cancel the attractive force of the permanent magnet 17, and the energy stored by the drive spring 15 causes the armature 13 to fly in the direction of the arrow in FIG.

Then, the printing wire 14 also protrudes in the same direction, and the platen 2
Printing is performed by colliding with the printing paper 3 set in the ink ribbon 7 via the ink ribbon 7.

When the printing magnet 10 is de-energized, the i of the core 12
lt[The force also dies out, and the armature I3 moves in the direction of arrow E in the figure due to the attractive force of the permanent magnet 17, is attracted to the core 12, and returns to the standby position.

In this way, the plurality of printing wires 14 are selectively driven,
Printing is performed on the printing paper 3 on the platen 2, and the print heads la and lb move in the direction of arrow B together with the carrier 4, and print each half of one line on the printing paper 3.

When printing for one line is completed, the paper transport mechanism is driven and the printing paper 3 is fed line feed in the direction of the arrow, and the print head la
, lb continue printing in the direction of arrow C.

In this way, the left and right halves of the printing paper 3 are simultaneously printed by the two print heads la and lb, and in this case, printing is performed at twice the speed compared to when there is only one print head. .

[Problem that the invention seeks to solve]

According to the above-mentioned conventional method, when printing is performed on the printing paper 3 by the two printing pads 1a+1b, the printing may have shading and become mottled on the left and right halves. That is, even though the excitation time of the electromagnet is exactly the same for the print heads la and lb, manufacturing variations such as dimensional errors and adjustment errors of the print heads la and lb during the manufacturing of the printer device. This causes variations in the characteristics of the print head. For this reason, during printing, the strength of the protruding force of the printing wire 14 to the platen 2 varies, resulting in uneven printing.
Print quality deteriorates. 7 dollars for printing.

Although it is possible to strictly control the dimensional error of 1b or to perform precise adjustment, it is not only costly but also has a limit on the accuracy that can be obtained. Therefore, a method has been used to prevent printing shading by selectively combining print heads la and lb with similar characteristics, but this method of selecting and combining also has the disadvantage of being costly, and furthermore, if only one print head breaks down, it can be assembled. This method has the drawback that it is necessary to replace the two pieces together, resulting in a lot of waste.

[Means for solving problems]

The present invention provides a printer apparatus including a switching instruction means for instructing switching of the excitation time length of each of a plurality of printing heads, and a setting means for setting different excitation times for the print head based on instructions from the instruction means. In this way, the above problem can be solved.

[Effect]

According to the present invention, instead of the conventional method of selectively combining a plurality of print heads with similar characteristics and installing them in a printer, different excitation times are set in the setting means, and this is switched off by the switching instruction means. In other words, by giving different excitation times to multiple print heads, it is possible to eliminate unevenness in print that occurs between different print heads, improving print quality, and also to improve print quality when one print head fails. This eliminates the waste of occasionally replacing even other non-faulty print heads in combination.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. FIG. 1 is a block diagram showing an embodiment according to the present invention, and FIG. 5 is a timing chart of FIG. 1. The same reference numerals indicate the same objects throughout the figures.

In FIG. 1, the print control circuits 9a and 9b selectively excite the plurality of print wires 14 of the print wires 1a+1b based on input print data a to perform a printing operation, and the excitation time is Excitation width control circuit 21a, 21b
A specified excitation time is given.

The changeover switches 20a, 20b are switching means for switching and specifying different excitation times. In this case, the excitation time is long 1+ compared to the standard excitation time to.

and short excitation time (-), and is initially set to the position of standard excitation time to.

The excitation width control circuits 21a and 21b have different excitation times set, and as shown in FIG. 5, (1) standard excitation time to, (2) short excitation time 1-, and (3) long excitation time. Three stages of t+ are set, and selector switch 2Q
It has a function of executing the driving commanded by the printing control circuits 9a, 9b according to the corresponding excitation time in accordance with the switching instruction of a, 20b.

That is, if the excitation time is increased, the driving time of the printing wire 14 becomes longer, and the force with which it collides with the platen 2 becomes larger, resulting in darker printing. On the other hand, if the excitation time is shortened, the print becomes lighter.

With such a configuration and function, if shading occurs in printing during printing tests during the manufacturing process or maintenance, the excitation time can be changed to + when the lighter printing is made darker, or the longer excitation time is increased. To make the dark one thinner, switch either the changeover switch 20a or 20b to a short excitation time t-.

Then, the set excitation time of either of the excitation width control circuits 21a, 21b is switched, and the excitation width control circuits 21a, 21b operate the print heads la, lb at different excitation times according to the print drive commands of the print control circuits 9a, 9b. Excite and drive printing.

In this way, if the printing by the print heads la and lb has shading on the left and right sides, it is possible to adjust by switching the changeover switch 20a20b to eliminate the shading in the printing.
Print quality can be improved.

Therefore, it is no longer necessary to select and combine two print heads with similar characteristics from among print heads with variations, and costs can be reduced.

In the above example, an example was explained in which different excitation times were set in three stages, but it is of course possible to increase the number of excitation times, and in fact, the more the excitation time is, the more convenient it is to eliminate the shading as it allows finer switching adjustment. .

Further, in the above example, the multi-printer has two print heads, but the present invention can also be applied to other numbers of print heads, and the same effect can be obtained even when applied to a shuttle printer.

〔Effect of the invention〕

As explained above, according to the present invention, (1) it is possible to easily eliminate unevenness in printing by a plurality of print heads, and it is possible to improve printing quality.

-Cost can be improved because it is not necessary to select and combine print heads with similar characteristics.

There is an effect.

[Brief explanation of drawings]

1 is a control block diagram showing an embodiment according to the present invention; FIG. 2 is a perspective view illustrating an overview of a multi-head printer; FIG. 3 is a side view showing a part of the print head in FIG. 2; Figure 4 is a control block diagram showing the conventional method, and Figure 5 is the control block diagram of the conventional method.
3 is a timing chart of the figure. In the figure, la and lb are print heads, 2 is a platen, 3 is printing paper, 7 is an ink ribbon, and 8a, 8b, 9a. 9b is a printing control circuit, 10 is a printing magnet, 1 is a core, 12 is a coil, 13 is an armature, 14 is a printing wire, 20a and 20b are changeover switches, and 21a and 21b are excitation width control circuits. Hayabusa/2 Ne2z

Claims (1)

[Claims] In an apparatus for printing on a printing medium placed on the platen member, the apparatus includes a platen member and a printing unit including a plurality of print heads having printing magnets arranged opposite to the platen member, A printer apparatus comprising: an instruction means for instructing switching of the excitation time length of each head; and a setting means for setting different excitation times for the print head based on instructions from the instruction means.