JPH05338215A - Driving method for print head of wire dot printer - Google Patents

Abstract

PURPOSE:To equalize the load of each pin of a print head by shifting the selective ranges of the pins of the print head at every line-feed printing when printing data satisfying specific conditions continue in two lines or more. CONSTITUTION:Transmission data from a host device 6 are received by a printer 1 through an interface circuit 7. A CPU 2 stores data received in a RAM 8 once, reads the data, analyzes the code of the data, and discriminates whether or not the data are the data of a character to be printed. When the data are character data, font data corresponding to said character are generated from a font ROM 9, in which font data corresponding to various characters are stored previously, by a character generating circuit 10 on the basis of the code read, and written to a buffer 11. When the character written are collected in a printing-line unit section, the characters are transferred to a print-head control circuit 12, the wire of a print head 13 is driven through a driver, an electromagnet is conducted selectively, and printing is conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a print head of a wire dot printer.

[0002]

2. Description of the Related Art In a wire dot printer, for example, every time data of a printing line unit, for example, one line of data is given from a high-order data processing device or a text creating device, that data is analyzed, and the data is analyzed as character data. In this case, this is replaced with the specified font data, each bit that makes up the font data is given to the print head control circuit, and the print head control circuit selectively drives the driver corresponding to one row of wire pins of the print head. Then, the driver operates the wire pin via the solenoid to print a character (character, number, symbol, or the like) in a predetermined typeface.

By the way, as for various characters, the font uses all pins of the print head (for example, from the first pin to the 24th pin in a 24-pin wire dot printer) like the Chinese character (hereinafter, Characters of the first kind) and characters that use only a part of the pins of the print head (for example, from the 7th pin to the 24th pin in a 24-pin wire dot printer) such as letters, numbers, or symbols (hereinafter referred to as the There are two kinds of characters).

However, in the conventional method of driving the print head in the wire dot printer, the correspondence between each bit forming the font data and each pin of the print head is constant regardless of the type of character. That is, when printing the first type character,
Within the range from the pin to the 24th pin, a specific pin determined by a font configuration preset for the first type character is selected and driven, and when the second type character is printed, for example, the 7th pin Similarly, within the range from the 24th pin to the 24th pin, a specific pin determined by the font configuration preset for the second type character is selected and driven. Further, in general, the paper conveyance amount at the time of line feed of the printer is determined by the initially set line pitch during a series of printing operations and is always constant.

[0005]

Therefore, depending on the type of document, in many cases only the second character is printed on each line, for example, accounting documents, statistical documents, European documents, etc., only numbers or only European characters. Is printed, or when the hex dump list is printed with a mixture of numbers and Latin letters in order to investigate the cause of printer malfunction, the load tends to be unevenly distributed on specific pins. Looking at the head as a whole, the print head replacement time is shortened due to uneven wear of the pins, and due to the same reason, the ink ribbon is also unevenly consumed in the width direction, so the replacement time is shortened. there were.

In view of the above points, the present invention checks the font configuration of print data for a print line unit (one line) to be received, and when there is no one that uses all of the pins constituting the print head (printing is performed). If the character to be printed is only the above-mentioned type 2 character), the load on each pin of the print head is made uniform by shifting the selection range of the pins of the print head each time a line feed is printed, and thus the life of the print head is shortened. It is an object of the present invention to provide a method for driving a print head, which can prolong the printing time.

[0007]

In order to solve the above-mentioned problems, the method for driving a print head according to the present invention is a method for receiving a print job.
Check whether there is a font size character that uses all the pins of the print head in the print data for a line,
When the print data satisfying the condition of no is continuous for two or more lines, the pin selection range of the print head is shifted each time a line feed is printed, and the paper conveyance amount at the time of line feed is changed according to the number of shifts of the pins. It is characterized in that the apparent line pitch of each print line is corrected to be equal.

In addition, it is checked whether or not the received print data for one line includes a character having a font size that uses all of the pins of the print head, and print data satisfying the condition of no is continued for two or more lines. In this case, the pin selection range of the print head is shifted each time line feed printing is performed, and the apparent line pitch of the print lines is made equal according to the number of shifts of the pin during the line feed. Whether or not there is a font size character that uses all of the pins of the print head in the received print data for one line and whether it has changed to a certain state When the change occurs, the stored correction amount is used to reversely correct the paper conveyance amount at the time of line feed so that the apparent line pitch becomes equal.

[0009]

When the print data for one line is received, the print data is stored in the buffer RAM. The print data is sequentially read, and the font data corresponding to the print data is called from the font ROM (font expansion processing is performed) and stored in the buffer. In the received print data for one line,
If the print data that does not include the type 1 character that uses all the pins of the print head is continuous on two or more lines, the font is expanded according to the conditions specified by the shift counter when the font is expanded from the print data on the second and subsequent lines. Shift the data. Each pin of the print head is driven via the print head control circuit based on the shifted font data. Therefore, when the print data is expanded into a font, the selection range of each pin of the print head corresponding to each bit forming the font data is shifted.

Instead of the method of shifting the driving range of each pin of the print head by expanding the font from the print data under the condition specified by the shift counter,
The same effect can be obtained by a method in which font expansion is performed in the conventional manner and the expanded font is shifted at the time of transfer from the buffer to the print head control circuit.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the print head driving method of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing a data processing unit, a movable unit, and a control unit of a general printer.

In FIG. 1, the CPU 2 of the printer 1 is R
Read the system program stored in OM3,
By executing it, the overall control of the operation as shown in FIG. 4 is performed. The operation panel 4 has indicator lamps and switches (not shown), and the input / output control is performed by the I / O port 5
Via the CPU2. The CPU 2 can also set valid or invalid of communication with the host device 6 which is a host computer. If the communication is valid, the transmission data from the host device 6 is received by the printer 1 through the interface circuit 7. CPU2 uses the received data as R
After the data is once stored in the AM8, it is read and the code of the data is analyzed to determine whether it is the data of the character to be printed or other data. For character data, as conceptually shown in FIG. 2, font data corresponding to various characters is stored in advance by the character font generation circuit 10 based on the read codes CC1, CC2, CC3, .... Font ROM9
To generate font data corresponding to the character and write it to the buffer 11. When the characters written in the buffer 11 are collected in print line units (one line), the CPU 2 transfers the characters to the print head control circuit 12, and the print head 1 via the drivers DR1, DR2, DR3 ,.
Electromagnets MG1, MG2, MG for driving the wire No. 3
Printing is performed by selectively energizing 3, ...
At the same time, the CPU 2 gives a command to the space control circuit 14 to drive the space motor 15 to drive the print head 1
Perform the spacing operation of the carriage on which No. 3 is mounted. Also, a terminator (line feed command) added to the end of the print data for one line received from the host device 6.
Based on the above, a line feed command is given to the line feed control circuit 16 to rotate the line feed motor 17 by a predetermined angle to convey the paper by a predetermined amount and perform a line feed.

The font data corresponding to the character data read from the RAM 8 which is generated by the character font generation circuit 10 by font expansion is composed of 24 bits because the print head 13 is composed of 24 wire pins as an example. And the buffer 11
As shown in FIG. 2, the font data of one character is divided into units of 1 byte (8 bits) and written in 3 bytes. When printing a character, if the character is a first type character that uses all the pins of the print head, 3 bytes of data is read from the buffer 11 and is read as one component of the print head control circuit 12. To the respective latch circuits 121, and the parallel output from the latch circuits 121 to the drivers DR1 to DR24 of the driver circuit 122, which is another component of the print head control circuit, to select to the electromagnets MG1 to MG24 of the print head. It is designed to be electrically energized. This point is not different from the print head driving method in the conventional wire dot printer.

However, in the method of the present invention, the CPU 2
Performs additional processing other than the above. That is,
The character data for one line of the RAM 8 received and stored by the printer 1 is only a character (the second type character such as a numeral, a Latin character or a symbol) that does not use all the pins (for example, all the 24 pins) of the print head. Check if there is,
If there is only the second type character, the CPU 2
As shown in, the CPU 2 causes the character font generation circuit 1
When the font is expanded by 0, or when the font data is transferred from the buffer 11 to the latch circuit 121 of the print head control circuit 12 as shown in FIG. Processing for shifting the entire 24 bits to the upper level is performed.

A specific example of the shift condition and the shift of the font data when the character font generating circuit 10 develops the font will be described below. CP
As conceptually shown in FIG. 3, the U2 includes a shift counter 21, a correction value storage unit 22, and a carry amount calculation unit 23.

Then, the CPU 2, as shown in FIG.
When the execution of the system program is started by turning on the power of the printer, first, the shift counter 21 is cleared (S1). Next, when communication with the host device 6 is enabled and data is received (Y in S2), the code of the received data is analyzed and stored in the RAM 8 (S3). When the character data for one line is received, whether or not the character data is only ANK (the second type character), that is, all 24 pins of the print head are used in the received character data. It is determined whether or not there is a character of the type (the first type character) by analyzing the received code (S4). When the character data for one line is only the second type character, the CPU 2 checks the value of the shift counter 21 at that time and shifts the font data as a whole by the same bit number as the value of the shift counter at the time of font development. (S
5).

Here, the concept of shifting the font data when the font is developed will be described with reference to FIGS. 5 and 6. 6A is a "new" font as a representative of Chinese characters stored in the font ROM 9, and B is a standard font of "H" as a representative of European characters. Then, FIG. 5A is a schematic diagram showing a storage state of 24-bit data in the first column of the standard font of the Latin character “H” in the font ROM 9. FIG. 3B shows a state in which the font data is shifted upward by 1 bit according to the value 1 of the shift counter 21 and stored in the buffer 11. In this way, the second
The data of the standard font of the seed character is 1 in 3 byte units by the shift processing when the font is expanded by the CPU.
The data "0" of the dot is erased, and the data "0" of the second dot is written in the first bit of the buffer 11.
Similarly, the 24th dot data “1” of the standard font is written into the buffer 11 at the 23rd bit. Data "0" is inevitably written in the 24th bit of the buffer 11.

The number of times font data can be shifted (maximum number of shifts) is set within a range in which fonts such as Western characters are not damaged by shifting. In the example of the standard font of the European character “H” in FIG. 4, the 7th of 24 bits (3 bytes) is used.
Since the bits up to the 24th bit are used, the maximum number of shifts is 6 corresponding to 6 bits.
The shift counter 21 has a count value of 6 as described later.
It is supposed to be cleared when it exceeds.

After the font development by the character font character generation circuit 10 (S5), the CPU 2 uses the carry amount calculation unit 23 to calculate the paper carry amount for determining the print position of the character whose font has just been developed on the paper. (S6). This calculation is based on the value of the shift counter 21 and the minimum unit transport amount by the sheet transport means (line feed motor 17
Using the transport amount per one rotation = ΔL), the standard transport amount,
That is, the standard line pitch (amount obtained by multiplying the minimum unit carry amount by the default rotation number T of the line feed motor = ΔL × T) is stored in the correction value storage unit 22 for correcting the printing position of the character whose font has just been developed on the paper. This is done by adding the line feed correction values that have been set. The line feed correction value is obtained by multiplying the minimum unit carry amount ΔL by the value C of the shift counter 21 (ΔL × C). For example, when the minimum unit carry amount ΔL per one rotation of the line feed motor 17 is 1/120 inch, the default number of rotations T of the line feed motor 17 is 24 and the standard line pitch is generally 1/5 inch. The minimum value of the line feed correction value in this case is 1/120 inch.

In step S6, if the paper transport amount is calculated, this correction value is stored in the correction value storage unit 22 (S7), and then the value of the shift counter 21 is incremented by 1 (S8). Next, it is determined whether or not the value of the shift counter 21 exceeds the maximum value, that is, the maximum number of shifts (6 in the case of the Latin character shown in FIG. 6) (S9). If it does not exceed the maximum value, the process proceeds to step S11 to control the line feed control circuit 16 based on the value of the result of the carry amount calculation to rotate the line feed motor 17 by a predetermined amount to feed the line. The character data which has been font-decompressed and written in the buffer 11 is given to the latch circuit 121 of the print head control circuit 12, and the drivers DR1, DR2, D of the driver circuit 122 are collectively operated based on the next clock.
Output to R3, ..., electromagnet MG1 of print head 13
.. are selectively energized to drive the pins to print on a predetermined line of the paper (S11).

In step S9, the shift counter 21
If the value of exceeds the maximum value, as described above, the shift counter 11 is cleared (S10), and then the line feed and the printing are executed (S11). The steps S4 to S6 are the font expansion and the carry amount calculation for printing the print data just received, while the steps S7 to S10 are the preparatory operation for printing the print data to be received next.

When it is determined in step S4 that the received data for one line is not only ANK, that is, when the print data including the first type character is received, whether or not the stored content of the correction value storage unit 22 is 0 or not. (S1
2). That is, the correction value storage unit 22 stores the correction value of the carry amount performed until the immediately preceding printing. If the correction value is not 0, a negative value of the stored correction value is added to the standard carry amount as an inverse correction value. That is, when the print data for one line received this time includes the type 1 character, the line feed from the print line of the preceding type 2 character at the standard line pitch (ΔL × T) is not enough. Since the standard font data of the seed character is shifted based on the value of the shift counter 21, the next line pitch is opened by the shifted amount. Therefore, when the method of the present invention is implemented, in step S13, a negative value of the correction value (ΔL × C) in the correction value storage unit 22 is added as an inverse correction value to the standard carry amount (ΔL × T) ( That is, it is subtracted), and the carry amount at line feed is obtained.

After the carry amount is calculated based on the reception of the print data including the first type character (S13), the correction value in the correction value storage unit 22 is cleared, and then line feed and printing are executed. When the correction value after receiving the data including the first type character is 0, that is, when the data including the first type charactor after the reverse correction of the transport amount is already received, the standard line pitch transport is performed. After setting the amount (S15), line feed printing is executed (S11).

As a specific example of the control according to the flowchart shown in FIG. 4 based on FIG. 7, a specific example of the correction of the carry amount when print data including various characters for several lines is sent from the host device 2 An example will be described.

In FIG. 7, the received print data D1
1, D12, ... D1n and terminator CR
It is determined that the print data for the first line has been sent.
Then, in this example, this print data is determined to be not only ANK by the determination in S4 of FIG. 4, and at this time, the correction value in the correction value storage unit is still 0, so CP
U2 calculates the standard carry amount (ΔL × T) in the case of the standard line pitch (S6 in FIG. 4), and supplies this to the line feed control circuit 16 to rotate the line feed motor 17 for a predetermined number of revolutions to execute line feed ( Because of S11), the character is printed at the center of the first line.

Next received print data D2 for the second line
If it is determined that 1, 2, 22, D2n are not only ANK, the correction value is 0, as in the case of the first row.
Since the carry amount calculated by the CPU 2 is ΔL × T, line feed is performed at the standard line pitch and printing is performed at the center of the second line.

Received data D31, D32 for the third line,
When D3n is first determined to be only ANK, the value of the shift counter 21 at that time is 0, so the carry amount calculated by the carry amount calculation unit 23 in this case is (ΔL × T) +
(ΔL × 0), and, as a result, as in the case of the second line,
The standard line pitch is fed from the first line, and only the second type character is printed on the third line. However, the shift counter is incremented by 1 before the line feed of the third line is printed, and the value becomes 1.

Next, the print data D41 for the fourth line,
If D42, ... D4n are also determined to be only ANK, then the shift counter is already 1 at this time, and therefore, when the font is expanded by the character font generating circuit 10, each character data of one line is shifted by one bit. At the same time, the carry amount calculated by the carry amount calculation unit is obtained by adding a correction value to the standard carry amount, that is, (ΔL × T) + (ΔL
X1), and after the line feed is performed from the print position of the third line with a line pitch obtained by adding the correction amount to the standard line pitch, only the second type character is printed on the fourth line. Although the carry amount is larger than the standard carry amount by the correction amount (ΔL × 1), since the character data given to the print head is moved upward by 1 bit, the characters printed on the third line and the fourth line The apparent line pitch between the characters printed on the eye is the same as the standard line pitch. Also at this time, the shift counter is incremented by 1 before the line feed of the fourth line is printed, and the value becomes 2, and the correction value (ΔL × 1) is stored in the correction value storage unit.

Similarly, print data D5 for the next fifth line
If it is determined that 1, D52, ... D5n are also ANK, the shift counter 21 has a value of 2 at this time, so that the font is expanded by 2 bits and the calculated carry amount is the standard carry amount (ΔL × After the line feed is performed at a line pitch obtained by adding the correction amount (ΔL × 2) to T), only the second type character is printed on the fifth line. The apparent row pitch between the fourth row and the fifth row is the same as the standard row pitch. Also, the shift counter is incremented by 1 and its value becomes 3,
Further, the correction value (ΔL × 2) is stored in the correction value storage unit.

On the other hand, the print data D for the sixth line
When it is determined that 61, D62, ... D6n are not only ANK, the CPU does not shift the data when developing the font of the received data, and the correction value in the correction value storage unit at that time is 2. , Its negative value (-2)
, The reverse correction value (ΔL × T) is added to the standard carry amount (ΔL × T).
(-2) is added to calculate the carry amount for line feed to the print position of the character on the sixth line. However, when the print data is received, it is not shifted when the font is expanded, and the carry amount is inversely corrected.
The apparent line pitch up to the print character of the line is the same as the standard line pitch. Then, after clearing the correction value in the correction value storage unit, line feed and printing are executed.

B1 to B8 in FIG. 6 are shifts at the time of font development and deviation of the actual print position from the standard print position when the character data for one line are all the second type characters for up to eight lines. Is shown by taking the case of printing the Latin character “H” as an example. Since the value of the shift counter when the print data of the seventh line is received is 7, the shift counter 21 is cleared in step S10 of FIG. Therefore, the print data for the eighth line received next is not shifted in the font data,
Similar to the case of printing the line, the actual print position is returned to the standard print position.

In the above embodiment, the description has been made on the assumption that the font structure of the type 2 character uses only 18 bits out of 24 bits. Therefore, the maximum number of shifts is 6, but the maximum shift number is 6. The number of times depends on the font composition. Further, in the above example, for the conveyance amount correction value at the time of line feed, the minimum unit conveyance amount and the pin interval of the print head are equal, for example, 1/12 for the sake of simplicity
The case of 0 inch was assumed. However, when the distance between the pins of the print head is 1/180 inch, the shift amount (movement amount) of the pins of the print head driven by the font data shift does not match the correction amount at the time of line feed. There is. In this case, a program may be incorporated so that the correction amount at the time of line feed is selected to be closer to the shift amount of the pin of the print head due to the data shift.

Further, in view of the object of the present invention, the shift direction and order at the time of font development can be arbitrarily determined according to the type of font and print head, and are limited to the above-mentioned embodiment. is not.

[0034]

As described above, according to the method of the present invention,
When print data for a line is received, it is checked whether or not the data is only the character of the second kind. When the data of only the character of the second kind is continuous for two or more lines, the font data is shifted by 1 bit. Since the print head control circuit is driven to shift the pins to be driven by the print head, even when characters of the same or the same font are printed, the pins to which the print head is driven each time a line feed occurs. Therefore, the uneven wear of the pins and the uneven wear of the ink ribbon are prevented, and the life of the print head and the ink ribbon is significantly extended as compared with the conventional printer.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a wire dot printer.

FIG. 2 is a conceptual diagram illustrating data processing until the received print data is expanded into a font and each pin of the print head is driven, and control of the print unit.

FIG. 3 is a block diagram showing an additional configuration of a CPU for carrying out the method of the present invention.

FIG. 4 is a flowchart illustrating the operation of the CPU.

FIG. 5 is a schematic diagram illustrating the concept of font data shift.

FIG. 6 is a schematic diagram showing font configurations of a first type character and a second type character and a printing position of the second type character after shifting.

FIG. 7 is an explanatory diagram showing a specific example of the type of character data, the font shift, and the paper transport amount at the time of line feed when print data for several lines is received.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location B41J 19/76 9212-2C 9211-2C B41J 3/10 114 C 8804-2C 3/12 B

Claims (2)

[Claims] (A) It is checked whether or not the received print data in print line units includes a character having a font size that uses all of the pins constituting the print head, and (b) the condition of no is satisfied. When the print data is continuous on two or more lines, the pin selection range of the print head is shifted each time line feed printing is performed, and (c) the paper conveyance amount at line feed is changed according to the number of pin shifts. A method for driving a print head of a wire dot printer, characterized in that the apparent line pitch of the print lines is corrected to be equal. 2. (a) It is checked whether or not the received print data for each print line includes a character of a font size that uses all of the pins forming the print head, and (b) the condition of no is satisfied. When the print data is continuous on two or more lines, the pin selection range of the print head is shifted each time line feed printing is performed, and (c) the paper conveyance amount at line feed is changed according to the number of pin shifts. Correction is made so that the apparent line pitch of the print lines becomes equal, and the correction amount is stored, and (d) all the pins that make up the print head are used in the received print data for each print line. It is checked whether or not there is a font size character from a certain state, and if there is a change, the stored amount of correction is used to make the paper conveyance amount at line feed so that the apparent line pitch becomes equal. Reverse correction Print head driving method according to claim 1, wherein the wire dot printer according to claim.