JP3234685B2 - Printer printing duty control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer for printing output data from a computer or the like in a dot matrix format, and more particularly to a print duty control device for suppressing overload of a print head.

[0002]

2. Description of the Related Art Conventionally, a printer that prints in a dot matrix format, for example, a dot impact printer, counts the number of print dots in each line for each print line in order to prevent print head print defects due to heat generation and damage to driver elements and the like. If the count exceeds the limit , the print head
Printing operation for cooling, for example, to print a plurality of times, or by a Printout operation such as stopping the printing, it was cooled to print head and the driver device.

Further, in consideration of the fact that only a specific printing element is used repeatedly for a long time, there has been a type in which a counter is provided for each printing element and the same control is performed.

[0004]

However, in a print head for printing with a print wire, the print wire repeats reciprocating motion at a very high speed in response to a demand for high-speed printing. There is a problem that the resin-made wire guide is melted when dense. This can occur in about 20 seconds in time. In order to avoid such a situation, printing cannot be stopped within a safe range unless the limit value is set sufficiently low. But,
If the limit value is set by paying attention only to the problem, printing is immediately stopped even in a print pattern in which the total number of print dots is not so large.

For example, in a print pattern such as a vertical line,
Although the number of print dots per print wire is small, all print wires have the same number of print dots. However, in a print pattern such as a horizontal line, only a specific print wire has a higher print ratio, but the remaining print wires do not print at all. Even if only the total number of dots in each line is judged, the two cannot be distinguished.
Printing is stopped early. That is, the processing capacity is reduced.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and makes it possible to continue printing without wasting the processing capacity and without causing printing failure or damage.

[0007]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention provides a printer for printing in a dot matrix format while moving a print head having a plurality of dot printing elements in a printing line direction. A plurality of first counting means for counting the number of print dots, a determination means for determining whether or not the number of dots counted by each counting means is equal to or more than a reference value, and counting the total number of print dots of each print line Second
Counting means, the third counting means for comparing the number of dots counted by the second counting means with each other, and counting the number of printed lines having the same number of dots, and the printing counted by the third counting means. When the number of rows is equal to or greater than a predetermined value, fourth counting means for counting the number of printing elements determined to be equal to or greater than the reference value by the determining means, and the number of printing elements counted by the fourth counting means. Print control means for executing a print operation for cooling the print head in accordance with the print condition.

[0008]

According to the above construction, when it is determined from the counting result of the third counting means that the number of printing lines whose total number of printing dots is close to each other is equal to or more than the predetermined value, the printing element which has printed the number of dots equal to or more than the reference value To cool the print head , depending on the number of
The printing operation, for example, executes Printout operations such as insertion or split printing operation downtime. That is, since the printing lines of the same or similar printing pattern are repeated and only a specific printing element is frequently used, the protection operation is performed. Even if a print line with a total number of dots that is close is repeated, if the specific print element does not print the number of dots equal to or greater than the reference value, then even if the same total number of dots is printed as in the above case, Only since the temperature does not rise, no protection operation is performed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments.

FIG. 1 shows a control configuration of the printer.
A central processing unit (hereinafter referred to as a CPU) 60 is connected to an external device (not shown) such as a host computer by an interface 6.
1 are connected. Various data such as character data to be printed and control data input from the external device are stored in a CPU.
The data is stored in an input buffer area 68 of a readable / writable memory (RAM) 63 by the controller 60. Among the stored data, the CPU 60 reads out a corresponding dot pattern from the character generator area 64 of the read-only memory (ROM) 62 by the CPU 60 and stores it in the print buffer area 69 of the RAM 63 as a dot pattern for one line. Is done. The CPU 60 sequentially reads out the dot patterns,
A plurality of printing elements of the print head 84 are supplied via a driver 85 via a driver 85, and a carriage (CR) motor 86 is driven via a driver 87 to print one line while moving the print head 84 in the print line direction. In a dot matrix format. After printing of one line is completed, the CPU 60 drives a paper feed (LF) motor 88 via a driver 89,
Feed printing paper at right angles to the printing line.

These controls are performed based on a program stored in a program memory area 65 of the ROM 62.
This is executed by the print control unit 81 of the PU 60.

After the power is turned on, the printer is initialized, as is well known. Particularly, according to the present invention, the print dot number memory area 70 of the RAM 63 is reset, and the timer section 78 of the CPU 60 starts (step 1 in FIG. 2). Print dot number memory area 70
Is provided for each print element of the print head, and adds and stores the number of print dots for each print element as described later. The timer section 78 counts the predetermined time in order to subtract a constant value from the value of the print dot number memory area 70 every predetermined time as described later.

When a print command is read out of the control data stored in the input buffer area 68 of the RAM 63 (step 2), the character data is converted into a dot pattern and expanded in the print buffer area 69, and the printing operation is started. Done. In parallel with this, the processing of step 3 and thereafter, which will be described later, is performed. If the read control data is other than the print command, other processing is performed according to the control data (step 20), and a subtraction processing (step 21) described later is also performed.

A print command is issued (step 2), and the control waits for a cooling time TP to be described later (step 3). The subtraction process (step 22) is also performed during this waiting time. Since the time required for cooling is 0 immediately after the power is turned on, the next process is immediately performed.

Prior to printing one line, the total dot number memory area 71 of the RAM 63 is reset (step 4).
The total dot number memory area 71 is for adding and storing the total number of print dots of one line. When the dot data is read from the print buffer area 69 and supplied to each printing element at the time of the printing operation, the adding unit 77 of the CPU 60 is used.
Indicates that the number of dots to be printed for each print element J is added to the print dot number memory area 70 and stored (steps 5, 6,
7) Also, the total dot number memory area 7
1 is also added and stored (step 8). The same process is repeated for all 24 print elements of the print head (step 9), and the same process is repeated for each dot digit as the printing of one line progresses until the end of the line (step 11).

During this printing, a subtraction process (step 10) from the print dot number memory area 70 is performed for each time counted by the timer section 78. In this process, as shown in FIG. 3, when the timer unit 78 counts a predetermined time (S23),
The subtracting unit 79 of the CPU 60 stores a constant value (ROM 6) from the corresponding print dot number memory area 70 for each print element J.
2 stored in the second area 66) (steps 24 to 26). This process is performed for all print elements (step 27).

The addition of the number of dots in step 7 is for estimating a temperature rise due to printing, and the subtraction in step 26 is for estimating a temperature drop due to natural heat radiation.

The printing of one line is completed (step 11).
And the same pattern determination unit 83 of the CPU 60 compares the count value of the total dot count memory area 71 with the count value stored in the previous row total dot count memory area 71B (step 1).
2). Then, the count value stored in the total dot count memory area 71B of the previous row is rewritten with a new value of the total dot count memory area 71.

If the difference between the total number of dots of the newly printed line and the total number of dots of the previous line is within the range of the value stored in the area 76 of the ROM 62, one is stored in the same line number memory area 72 of the RAM 63. Is added and stored (step 13).
If the difference between them is large, the same line number memory area 72
Is reset (step 14). Since the difference between the two lines is determined to determine whether printing of substantially the same or similar pattern is repeated, the range of the difference is set relatively small.

The comparing unit 80 of the CPU 60 determines whether the number of rows stored in the same line number memory area 72 exceeds the limit value of the area 74 of the ROM 62 (step 15). If the number of lines exceeds the limit value, the number of printing elements that are printing beyond the reference value among the printing elements is counted (step 16). That is, first, as shown in FIG. 4, the element number memory area 73 of the RAM 63 is reset (step 28). And the judgment unit 80B of the CPU 60
Is a reference value memory area 67 of the ROM for each printing element J.
It is determined whether or not the reference value is exceeded (step 29).
31), the element number counting unit 82 of the CPU 60 adds the number of printing elements exceeding the number to the element number memory area 73 of the RAM (step 32). This is repeated for a total of 24 printing elements. Next, regardless of whether the number of lines having substantially the same number of dots exceeds the limit value, the total unit 80C of the CPU 60
As a result, the values in the print dot number memory area 70 are summed up for all print elements and stored in the total value memory area 71C (step 17). The difference between this total value and the value of the total dot number memory area 71 is that the former sums up the values after the subtraction processing and sums over the number of lines, whereas the latter sums up the subtraction processing. This is the point that is the dot number obtained by adding only one line without performing. Note that the total value may be obtained by summing the number of print dots of each print element and then subtracting a fixed value at predetermined time intervals.

The above total value estimates the temperature of the entire print head in consideration of natural heat radiation. The CPU 60
The print head cooling time, that is, the stop time T1 corresponding to the total value is read from the stop time memory area 75 of the ROM 62 (step 18). Further, the stop time T2 corresponding to the number of printing elements exceeding the reference value counted in step 16 is also read. If the number of excess printing elements is zero, T2 is zero. Then, the CPU 60 calculates the actual stop time TP based on the both stop times T1 and T2 (step 1).
9). This stop time TP is determined by the print control unit 81 of the CPU 60 in step 3 where printing is stopped for a predetermined time in accordance with the temperature of the print head and the number of printing elements used frequently, and cooling is performed. This starts the line printing operation. During this stop time, the carriage may be driven by driving the CR motor 86 to promote cooling of the print head.

Instead of stopping the printing, it is also effective to divide the printing elements into a plurality of groups and print the same print line in a plurality of times for each group to cool the print head.
In this case, the printing elements used frequently are assigned to groups to be printed later. The printing program for this is stored in the ROM 62 instead of the stop time memory area 75.

As described above, when the printing lines whose total dot numbers are close to each other are repeated a predetermined number of times (step 15), and there are printing elements that have been used more frequently than the reference value (step 6), a large number of printing elements are used. As in the case of the horizontal line pattern, even if the total number of dots is small, only a specific printing element group is at a high temperature. Even if a print line having the same total number of dots is repeated as in the case of a vertical line pattern, only a specific print element is not used frequently, so protection is performed unless the value of the total memory area 71C becomes excessive. Does not work. That is, unnecessary stop and divided printing are not performed.

[0024]

The present invention as described above, according to the present invention, when the total number of dots is the number of print line closer to each other than the limit value, depending on the number of print elements that print the number of dots than the reference value, the print heads
Performs a printing operation to cool the card. In other words, even if the total number of dots is small, the protection operation is performed when printing lines of the same or similar pattern are repeated and only a specific printing element is frequently used. However, even if a printing line having a total number of dots is repeated, if a specific printing element does not print the number of dots equal to or larger than the reference value, only a specific portion does not become hot, so that no protection operation is performed. Therefore, unnecessary stop operations are reduced, and printing can be continued without wasting the processing capacity and without causing printing failure or damage due to heat generation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration for controlling a printer according to the present invention.

FIG. 2 is a flowchart of a control process.

FIG. 3 is a flowchart of a subtraction process.

FIG. 4 is a flowchart of a process for counting the number of excess printing elements.

[Explanation of symbols]

77, 70 First counting means (adding section, print dot number memory area) 80B, 67 Judging means (judging section, reference value memory area) 77, 71 Second counting means (adding section, total dot number memory area) 83, 76, 72 Third counting means (same pattern determining unit, range memory area, same line number memory area) 73, 82 Fourth counting means (element number memory area, element number counting unit) 81, 75 Print control Means (print control unit, stop time memory area)

Claims (7)

(57) [Claims] 1. A printer for printing in a dot matrix format while moving a print head having a plurality of dot printing elements in a printing line direction, wherein a plurality of first counting means for counting the number of printing dots for each printing element are provided. Determining means for determining whether or not the number of dots counted by each counting means is equal to or greater than a reference value; second counting means for counting the total number of printing dots in each printing line; and counting by the second counting means. A third counting means for comparing the number of printed lines with each other and counting the number of printed lines having a similar number of dots; and when the number of printed lines counted by the third counting means is equal to or more than a predetermined value, the determining means mark in accordance with the number of printing elements and a fourth counting means for counting the number of has been printed elements determined to be equal to or larger than the reference value, its fourth counting means has counted by
And a print control unit for executing a print operation for cooling the character head . 2. The apparatus according to claim 1, further comprising: means for subtracting a fixed value from the number of dots counted by said first counting means at predetermined time intervals. A print duty control device for a printer that determines the number. 3. The printing control means according to claim 1, further comprising means for subtracting the number of dots counted by said first counting means by a predetermined value at predetermined time intervals and summing up all the printing elements. , According to the total value of the summing means and the number of printing elements counted by the fourth counting means,
A print duty control device of a printer that executes a print operation for cooling a print head . 4. The printing duty control device according to claim 1, wherein said first counting means sequentially adds the number of dots to be printed for each printing element in accordance with a printing operation of a printing head. 5. The print control device according to claim 1, wherein the print control unit performs a print operation including a pause time corresponding to the number of print elements counted by the fourth counting unit , as a print operation for cooling a print head. The print duty control device of the printer to be executed. 6. The print duty control device according to claim 5, wherein the print control unit moves the print head along a print line without printing during the pause time. 7. The method of claim 1, wherein the print control means, as a printing operation for cooling the print head, dividing the print elements into a plurality of groups, is printed separately by the same print line per the group operation The printer's print duty control device that executes .