JPS6342874A - Printer - Google Patents

Abstract

PURPOSE:To ensure that electrical capacities of a printing head and a driving power source circuit for the head can be set to be low, by discriminating a limit of the number of dots capable of being printed in the current printing by a discriminating means based on the number of dots counted and a time count, and controlling the number of dots to be printed in the current printing on the basis of the result of discrimination. CONSTITUTION:A calculating and discriminating part 28d is a calculating and discriminating means which performs calculations based on the number N1 of dots printed in the previous printing, a time count T, the number N2 of dots to be printed in the current printing and a predetermined value N0 and discriminates a limit of the number of dots capable of being printed in the current printing. The part 28d calculates the limit (n) of the number of dots capable of being printed based on a heating level obtained by taking into account the progress of cooling from the previous printing to a moment immediately before the current printing, based on the number N1 of dots printed in the previous printing and the time count T, and compares the number (n) with the number N2 to be printed in the current printing. When N2 <= n, the part 28d directly commands a printing operation, whereas when N2 > n, the part 28d bisects images to be printed and then commands the printing operation. Thus, a printing load is restricted, whereby a printing head 1 can be protected against burning, and maximum ratings of the printing head 1 and a head-driving power source circuit can be appropriately set to be low. Accordingly, reductions in size and cost can be contrived.

Description

[Detailed Description of the Invention] [Summary] A serial printer that forms print by dots, which includes dot counting means for print data, time counting means from the end of the previous printing energization to the start of the current printing energization, and the counted dots. By providing a judgment means to judge the limit value of the number of dots that can be printed this time based on the number and time count value, it is possible to control the printing load and reduce the maximum rating of the print head and head drive power circuit, etc., thereby improving costs. can be achieved.

[Industrial application field]

The present invention relates to a serial printer such as a wired throat printer, and more particularly to a printer that can improve the cost of a print head, head drive power supply circuit, etc. by controlling printing load.

Recently, with the advancement of office automation, various computer terminals and word processors have been developed.

Wire tod printers and thermal printers have been developed and put into practical use as print output devices for facsimiles and the like.

These printers form prints in the form of dots by selectively energizing multiple printing elements, and the ratings of the print head, head drive power supply circuit, etc. are set based on the maximum energization value. A method that can optimize or protect against burnout is desired.

[Conventional technology]

A conventional example will be explained with reference to FIGS. 6 to 8.

The same reference numerals indicate the same objects throughout the figures.

As shown in FIG. 6, a print head 1 and a ribbon cassette 4 are mounted on a carrier 5, and a print head 1 is placed on a print paper 3 set on a platen 2 with a print ribbon 4a supplied from the ribbon cassette 4. are facing each other through.

The carrier 5 is slidably fitted into a guide shaft 6 arranged parallel to the platen 2 , and a feed screw 7 parallel to the platen 2 is also screwed into the carrier 5 .
The print head 1 is connected to the space motor h via the space motor h, and the print head 1 can be moved back and forth in the directions of arrows A and B in the figure by forward and reverse rotation of the space motor. Further, the printing paper 3 is transported in the direction of arrow C by the transport mechanism 9.

The print head 1 uses dots to form prints.
Equipped with multiple printing magnets.

As shown in Fig. 7, the printing magnet lO is the core 1)
a. Electromagnet 1) consisting of a coil llb. Armatier 13 with wire 12 at the tip. A drive spring 14 that elastically supports and drives the armature 13. York 15
a, 15b, and a permanent magnet 16 that normally attracts the armature 13 to the core lla.

Therefore, when a printing pulse is sent to the printing head 1 and a current is applied to the coil llb of the printing magnet 10 to cancel the magnetic flux of the permanent magnet 16 and the electromagnet 1) is excited, the electromagnet 1) is attracted to the electromagnet 1). The armature 13 is released and rebounds in the direction of arrow E due to the restoring force of the drive spring 14, and as a result, the printing wire 12 protrudes in the same direction.
The leading edge collides with the printing paper 3 via the printing ribbon 4a, dot printing is performed, and the excitation is immediately released to restore the printing state.

Further, in FIG. 8, the interface control unit 17 receives a print information signal a sent from a host device such as a computer (not shown), distinguishes between print data b and control data, and sends a space signal C2 to the space control unit 17. A line feed signal d is sent to the line feed control unit 19, and the print data b
It has a function of sending the data to the buffer 20.

The print control unit 21 has a function of causing the head drive circuit 22 to operate the print magnet of the print head 1 based on print pulses sent from the buffer 20 .

Further, 23 and 24 indicate a motor drive circuit, and M2 indicates a line feed morph.

With such a configuration and function, when the space signal C to start printing is sent from the interface control unit 17, the space control unit 18 is activated, and the print data b sent from the buffer 20 is sent to the print control unit 21. The print pulse actuates the RAD 1 for printing. Printing is thus performed, and the space controller 18 causes the motor drive circuit 23 to rotate the space motor j, and the print head 1 prints on the print paper 3 while moving in the direction of arrow A together with the carrier 5.

When one line of printing is completed, a line feed signal d is sent to the line feed control unit 1.
9 and is sent to the line feed motor M2 by the motor drive circuit 24.
rotates, and the printing paper 3 is fed line feed in the direction of arrow C.

In this manner, dot printing is performed.

[Problem that the invention seeks to solve]

According to the above-mentioned conventional method, there are cases where the print head 1 uses part of a plurality of print wires 12 and cases where many print wires 12 are used at the same time. A plurality of printing magnets 10 are excited at the same time, and the amount of energization increases in proportion to the number of printing magnets, resulting in heavy duty and increased heat generation.

Furthermore, when printing a large number of dots in succession, the next dot will be printed with the printing pulse before it has cooled down, and the temperature of the printing pad 1 will gradually rise due to the so-called heat accumulation effect, causing overheating. It will eventually burn out. Similarly, the power supply circuit of the print drive circuit 22 is continuously loaded.

To deal with this, the design is designed with the maximum rating of t flow capacity that can withstand continuous maximum load, and therefore the difference between the maximum rating and the steady rating is significant, making it difficult to print.

There is also the problem that the capacity of power supply circuits, etc. is of excessive quality, increasing costs.

[Means for solving problems]

FIG. 1 is a block diagram of the principle of the present invention.

In the figure, 25 is a dot counting means for counting the number of dots in the print data, 26 is a time counting means for counting the time from the end of the previous printing energization to the start of the current printing energization, that is, the dot printing interval time, and 28 is the number of dots counted. This determination means determines the limit of the number of dots that can be printed this time based on the number of printed dots and the time count value.

Therefore, based on the determination result by the determination means 28, the driving of the printing element is controlled.

[Effect]

The number of dots in the print data is counted by the dot counting means 25, and on the other hand, the time from the end of the previous printing energization to the start of the current printing energization is counted by the time counting means 26.

Based on the counted number of dots and the time count value, the determining means 2
8, the limit of the number of dots that can be printed this time is determined, and the number of dots that can be printed this time is controlled based on this determination. In other words, by dividing the printing into multiple times to reduce the load of one printing, etc., by controlling the drive of the printing element so that the load current does not exceed a certain value, the printing head and printing speed are reduced. The electric capacity of the drive power supply circuit for the head can be set to a low value, and costs can be improved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 to 4. The same reference numerals indicate the same objects throughout the figures.

Figure 2 is a block diagram of the main parts, and the one corresponding to Figure 1 is 1.
It is shown surrounded by a dotted chain line.

In the figure, the counter 25a is dot counting means for counting the number N2 of dots in the print data b.

The timer 26a is a time counting means that counts the time from the end of the previous printing energization to the start of the current printing energization.

The previous dot number memory 27 is a memory that stores the previous printed dot number N.

The printable limit value table 28a is, for example, a ROM, and is a memory in which the limit value of the number of printable dots corresponding to the combination of the previous printed dot number N and the time count value T is stored.

The comparison/judgment section 28b compares the number of printable dots n and the number of dots N.
2 and sends the determination result to the print control section 21a.

Since it has such a configuration and function, the operation will be explained with reference to the flowchart in FIG. 3 and the timing chart in FIG.
starts and starts counting time.

(2) The current print data b sent from the interface control unit I7 is stored in the buffer 20 and sent to the print control unit 21a.

(2) Then, the timer 26a stops counting time at the timing of point (2) in FIG. 4, and sends the time count value T to the printable limit value table 28a. Timer 26a is cleared.

(2) Also, at the timing of point H in FIG. 4, the previous printed dot number N1 stored in the previous dot number memory 27 is read out and sent to the printable limit value table 28a.

(2) On the other hand, the number of printed dots of the print data b is counted by the counter 25a, and the current number of printed dots N2 is sent to the comparison/judgment section 28b at the timing of point (2) in FIG.

■Number of dots printed last time N1. Based on the time count value T, the printable limit value n is read out from the printable limit value table 28a, and is sent to the print control unit 21a at the timing of point 2 in FIG.

(2) The comparison/judgment unit 28b compares the number of dots to be printed this time N2 with the printable limit value n, and notifies the print control unit 21a of the determination result at the timing of point (2) in FIG. That is, if N2≦n, the printing control section 21a directly sends out the printing pulse and the printing operation is performed.

(2) If N2>n, the printing operation is performed by dividing the printing into upper and lower halves. That is, printing is divided into a plurality of times to lighten the load of one printing.

(2) When printing is completed, the number N2 of dots printed this time is sent from the counter 25a to the previous dot number memory 27, where it is updated and stored. That is, the number of dots printed this time will be Nl for the next printing. Thus, the count of the counter 25a is cleared.

A different embodiment is shown in FIG. The same symbols as in FIG. 2 indicate the same objects. Further, in FIG. 5, parts corresponding to those in FIG. 1 are surrounded by a chain line. The difference between the embodiment shown in FIG. 5 and the embodiment shown in FIG. 2 is that the printable limit value n is determined by calculation means rather than by searching from the printable limit value table 28a.

That is, in the figure, the setting section 28c is a memory in which a predetermined value of the number of dots is set.

The calculation/judgment unit 28d is a calculation/judgment means that performs calculations based on the previous print dots D, N+, the time count value T, the current print dot number NZ+, and a predetermined value N0, and determines the limit of the current printable dot number.

Therefore, from the number N of dots printed last time and the time count value T, the printable limit value n is calculated from the heating level that includes the cooling progress from the previous printing to just before printing this time, and this is compared with the number N2 of dots printed this time, If N2≦n, the printing operation is directly commanded, and if N,>n, the printing is divided into upper and lower halves and the printing operation is commanded.

By suppressing the printing load in this way, the print head 1 can be protected from burnout, and the print head 1. Since the maximum rating of the power supply circuit for driving the head and throat can be appropriately set to a low value, size reduction and cost improvement can be achieved.

In the above embodiment, the case of a wire tod printer has been described, but the present invention can also be applied to other printers that form prints in the form of dots by energizing a printing element, such as a thermal printer, and similar effects can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent excessive quality of the print head, head drive power supply circuit, etc., and it is possible to obtain a smaller, lower-priced printer.

[Brief explanation of the drawing]

Fig. 1 is a principle block diagram according to the present invention, Fig. 2 is a schematic diagram of main parts showing an embodiment according to the present invention, Fig. 3 is a flowchart of the embodiment, Fig. 4 is a timing chart of the embodiment, and Fig. 4 is a timing chart of the embodiment. Fig. 5 is a block diagram of main parts showing different embodiments of the present invention, Fig. 6 is a perspective view showing an outline of a wire tod printer, Fig. 7 is an explanatory diagram of a printing magnet, and Fig. 8 is a block diagram showing a conventional example. It is. In the figure, 1 is a print head, IO is a print magnet, 1) is an electromagnet, 12 is a print wire, 17 is an interface control unit, 18 is a space control unit, 19 is a line feed control unit, 20 is a buffer, 21 is a print control unit , 22 is a head drive circuit, 23.24 is a motor drive circuit, 25 is a dot counting means, 25a is a counter, 26 is a time counting means,
26a is a timer, 27 is a previous print dot memory, 28 is a determining means, 28a is a printable limit value table, 28b is a comparison/judgment section, 28c is a setting section, and 28d is a calculation/judgment section.゛・Dan No. 2 z Soku 7 mag rod /) 1st page ￥ 7 Kaku Z Jusen Ita゛

Claims (3)

[Claims] (1) In a device that prints dots on a printing medium by selectively energizing a plurality of printing elements facing the printing medium, a dot counting means (25
), a time counting means (26) for counting the time from the end of the previous printing energization to the start of the current printing energization, and determining the limit of the number of dots that can be printed this time based on the counted number of printed dots and the time count value. Judgment means (28)
A printer comprising the following: Driving and controlling a printing element based on a determination result by the determining means (28). (2) The determination means (28) includes printable limit value storage means in which a limit value of the current printable dot number corresponding to the combination of the counted dot number and the time count value is stored. A printer according to claim 1. (3) The determining means (28) includes a setting section in which a predetermined value of the number of print dots is set, and a limit value of the number of dots that can be printed this time based on the predetermined value, the counted number of dots, and the time count value. 2. The printer according to claim 1, further comprising calculation means for calculating.