JPH0437789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a printing method for a multi-head dot printer, and more particularly to a printing method when the head generates heat.

(Background technology) Conventionally, multi-head dot printers (hereinafter referred to as
When printing continues with a high print duty (called an LP), the print head used in the LP starts to generate heat. If the heat generation temperature becomes high, the excitation coil for driving the printing element used in the print head may burn out, so set a certain temperature T ₁ °C and reduce the printing speed.
The actual printing duty is lowered. If the print head continues to generate heat even when the printing speed is reduced, a limit temperature T ₂ ℃ is set (T ₂ > T ₁ ), and when the temperature reaches T ₂ ℃, printing is stopped and the print head is It waits for the head to cool down and then starts printing again when the head temperature falls below T ₂ °C. However, if the printing speed is reduced, Figure 5 a and b
As shown in the figure, there is a delay time from the print command pulse to printing, and this time is approximately 370 μs with conventional equipment.
This time is constant regardless of printing speed. As shown in Figure 5a, when the printing command pulse interval in the normal case is 740μs, the printing delay time is 1/2, so the printing speed is normal as shown in Figure 5c, b. It is printed at almost the same position whether the direction is the forward direction or the reverse direction (in Figure 5 c, the upper side shows the forward direction printing and the lower side shows the reverse direction printing. (A in Fig. 5c indicates the printing position.) On the other hand, when the printing speed decreases as shown in Figure 5b, the ratio of the printing command pulse to the printing delay time decreases to 1/3 or 1/4 in proportion to the decrease in printing speed. , the apparent printing delay decreases, and as in the case of the decrease in printing speed shown in Figure 5c, a difference δ between actual printing occurs between forward direction and reverse direction printing, and the difference δ is There was a drawback that the printing speed increased in proportion to the decrease in printing speed (in c of Fig. 5,
The upper side is when printing in the forward direction, and the lower side is when printing in the reverse direction. ).

Also, as a second drawback, considering printing quality,
When considering printing under conditions where the difference δ does not change significantly compared to normal printing, the limit for the reduction in printing speed is about 80% of the normal printing speed, and this does not mean that the temperature of the print head can be reduced by that much. Another drawback was that the printing temperature reached the point where printing should be stopped without being able to do so.

(Object of the Invention) The object of the present invention is to eliminate such conventional drawbacks, and to provide a multi-head dot printer that can continue printing while maintaining print quality even when high print duty continues and the print head temperature rises. The purpose is to provide a printing method.

(Summary of the Invention) The printing method of the multi-head dot line printer of the present invention includes: a print head having a plurality of printing elements; a carriage on which the print heads are mounted at regular intervals; and the carriage prints according to the printing. It has a space motor that moves the paper to the left or right, and a line field motor that moves the printing paper to create a line feed, and prints one line using the plurality of print heads, and each printing a detection means for detecting the temperature of the head; and a print head to be used for printing from among the plurality of print heads is selected based on the temperature of each of the print heads detected by the detection means, and the space motor and the print head are selected from among the plurality of print heads. and control means for controlling the line field motor, and the control means controls all the print heads to perform printing when the temperature of all the print heads is below a predetermined first temperature (T1°C). the temperature of one of the print heads is within the predetermined first temperature range;
When the temperature exceeds , the first print head for printing is selected while the carriage is moving to the right, and the second print head is selected for printing while the carriage is moving to the left. The present invention is characterized in that a head is selected and control is performed so that one line of printing is performed using the selected first and second print heads.

Hereinafter, the present invention will be explained based on embodiments with reference to the drawings.

(Example) Figure 3 has four print heads as an example.
FIG. 3 is a plan view of the printing mechanism section of the LP, in which figure a shows the time when printing for one line starts, and figure b shows the time when printing ends. 1 is the platen, 2 is the space motor (hereinafter referred to as
It is called an SP motor. Note that the SP motor is not shown. )
Carriage moving left and right, 3-1, 3-
2, 3-3, 3-4 are print heads fixed to the carriage 2 at regular intervals, 4 is printing paper, A ₁ ,
A ₂ , A ₃ , and A ₄ are print heads 3-1 and 3-, respectively.
2, 3-3, and 3-4 printing ranges are shown. here,
If the number of characters printed for one line is 88 characters, there are four character heads (3-1, 3-2, 3-3, 3-4), so each head prints 22 characters in one printing operation. I will do it.

FIG. 1 is a block diagram of an LP showing an embodiment of the present invention. 11 is the printing head 3-1, 3-
2, 3-3, and 3-4 temperature sensing units that sense the temperature; 12 is an SP motor that moves the carriage 2 in Figure 3 left and right; 13 is an LF motor that feeds the printing paper 4 in Figure 3; 14 -1,14-2,14-
3, 14-4 are the corresponding print heads 3-1, 3
-15 is the SP motor 12 and LF
Motor 13 and head driver 14-1, 14-
2, 14-3, 14-4, etc.

2a to 2c are operation timing diagrams of the LP shown in FIG. 1.

An example of the printing operation will be described below with reference to FIGS. 1 and 2. Each print head 3-1, 3-
The temperatures detected from the printheads 2, 3-3, and 3-4 are detected by the temperature sensor section 11, and depending on the detection level, the temperatures detected from the printheads 3-1, 3-2, 3-3, and 3-4 are selected.
Head drivers 14-1, 14- corresponding to 4
All or any of 2, 14-3, and 14-4 are selected, and then the SP motor 12 is driven,
Print data is given to the selected head driver from a control device (not shown) via the printing mechanism control unit 15, and one line can be moved one time to the left or right of the head carriage 2, or moved several times (for example, by forward movement). Printing is performed by two movements (travel and reverse travel). For example, if the temperature detection level of all print heads is below T ₁ °C, the second
As shown in Figure a, all the print heads 3- are printed at once when the carriage 2 in Figure 3 is running forward or reverse.
Head drivers 14-1, 14-2, 14-3, 14-4 corresponding to 1, 3-2, 3-3, 3-4
Select and print one line. Therefore, at this time, one line is printed in the forward run, and one line is printed in the next reverse run. In each of FIGS. 2a to 2c, when a pulse exists (on), the component corresponding to the pulse is in the on state,
When there is no pulse (off), it is in the off state. Next, the temperature detection level of one print head is
If the temperature is higher than T ₁ °C and lower than T ₂ °C, the head drivers 14-1 and 14-2 corresponding to the print heads 3-1 and 3-2 are selected in forward running as shown in Fig. 2b, and printing is performed. Without performing a line feed (LF), the head drivers 14-3 and 14-4 corresponding to the print heads 3-3 and 3-4 are selected in reverse running and printing is performed to print one line. Therefore, in this case, one line is printed and a line feed is performed by running the machine twice, the forward run and the reverse run, at the same printing speed as in the case of FIG. 2a. Next, if the print duty is high and the head temperature rises even if printing is done in two times, and one of the four heads reaches the limit temperature of T ₂ °C, the temperature detection level will rise to T _{2 °} C.
℃ or more. In this case, as an example, if the second print head 3-2 reaches the limit temperature, the fourth print head 3-2
As shown in the figure. In this case, print head 3-2 cannot print, so print head 3-1 can print instead.
An additional 22 characters, which is the printing range of print head 3-2, are printed. Therefore, print head 3-1 prints a total of 44 characters. Figure 2c is an example of this.First, in the first half of forward printing, print head 3-
Select the head driver 14-1 corresponding to 1 and print, then continue with a space and select print head 3.
-1 is spaced to the reverse printing start position of print head 3-2. After that, without performing a line feed, during the first half of reverse travel, the head driver 14-1 corresponding to the print head 3-1 is selected and the print head 3-1 is moved to the print head 3-1.
2 performs printing within the range that should be in charge. Thereafter, the head drivers 14-3 and 14-4 corresponding to the print heads 3-3 and 3-4 are selected to perform printing. Therefore, in this case, one line is printed by forward running twice the normal distance and reverse running twice the normal distance, and then a line feed is performed.

As explained above, according to this embodiment, when the temperature detection level T ₁ °C and T ₂ °C of the print head is used, the printing speed is reduced to 1/2 of the normal printing processing speed when the temperature detection level T ₁ °C is reached, and Temperature detection level T ₂ ℃
When , the carriage running speed can be changed to 1/4 of the normal printing processing speed while keeping it constant, so there is no deterioration in printing quality. In addition, the effective printing processing speed can be significantly reduced to 50% at 1/2 and 25% at 1/4 compared to the conventional 80%, so the situation where the LP stops due to an alarm due to temperature rise is extremely limited to high printing duty. This occurs only when the lag continues, and does not normally occur, causing the LP to stop and cause the so-called "dummari".
The condition no longer occurs.

(Effects of the Invention) As explained above, according to the present invention, there is provided a printing method for a multi-head dot printer that can continue printing while maintaining print quality even if high print duty continues and the temperature of the print head rises. can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIGS. 2 a to 2 c are operation timing diagrams of the apparatus shown in FIG.
Figure 3 a and b are Kanji characters with four printing heads.
A plan view of the printing mechanism section of the LP, FIGS. 4a and 4b are plan views of the printing operation of an embodiment of the present invention, and
Figures a to c are diagrams showing printing states when the printing speed is constant and when the printing speed is decreased. 1...Platen, 2...Carriage, 3-1,
3-2, 3-3, 3-4...Print head, 4...
Printing paper, 11...Temperature sensing section, 12...SP
Motor, 13...LF motor, 14-1, 14-
2, 14-3, 14-4...Head driver, 1
5...Print mechanism control unit, _A1 to _A4 ...Print head printing range.

Claims (1)

[Scope of Claims] 1. A printing head having a plurality of printing elements, a carriage on which the printing head is mounted at regular intervals, and a space motor for moving the carriage to the left or right with respect to the printing paper according to printing. and a line field motor that moves the printing paper to perform a line feed, and prints one line using the plurality of printing heads. a detection means for detecting, and a print head to be used for printing from among the plurality of print heads is selected based on the temperature of each print head detected by the detection means, and the space motor and the line field motor are selected from among the plurality of print heads. and a control means for controlling all the print heads for printing when the temperature of all the print heads is below a predetermined first temperature (T1°C). , the temperature of one of the print heads is within the predetermined first temperature range.
When the temperature exceeds , the first print head for printing is selected while the carriage is moving to the right, and the second print head for printing is selected while the carriage is moving to the left. A printing system for a multi-head dot line printer, characterized in that a print head is selected and the selected first and second print heads are controlled to print one line. 2. The control means further includes a second temperature control means for controlling any of the print heads to have a second temperature higher than the first predetermined temperature.
When the temperature reaches a predetermined temperature (T2°C), a plurality of print heads including the print head adjacent to the print head are selected for the rightward movement and leftward movement of the carriage, and Claim 1, characterized in that during the rightward movement and the leftward movement, the selected printing head is controlled to print one line.
The printing method of the multi-head dot line printer described in .