JP2002248800A - Line printer and method of printing therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of inability, when a few print dot elements are broken and the other print dot elements are good, to adequately print so that a print head have to be replaced as the end of the life and the term of the life is reduced when the printing data is concentrated to a certain dot and to extend the life of the head. SOLUTION: In an adequate printing (1) by original print data, when 10th and 31st heating elements are broken, the printed result becomes one shown by (2) in the drawing as it is. Data '0' is inputted to the 10th and 31st elements. Data to be inputted to the 10th element is inputted to the 11th element and after that the data is shifted by one in the same manner. As the data '0' is already inputted to 31st element, the data is inputted to the 32nd element. As a result, it is possible to obtain the converted result without a trouble and the desired printed result shown by (3) when the adequate content of the original printed pattern (1) is confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer which is mounted on a POS or an ECR and prints data on a recording paper such as a receipt. More specifically, the present invention relates to a fixed printer such as a line thermal printer. The present invention relates to a printing control method for a printer that performs printing for each dot line using a line head.

[0002]

2. Description of the Related Art In the case of a thermal line printer, a thermal head is composed of a plurality of heating elements arranged linearly, a driver IC for controlling the heating of these heating elements, and the like. It has shift register cells and switching elements that correspond one-to-one, and the shift register cells are connected in series to form a shift register.

As a conventional printing method using a thermal head as described above, when print data for one dot line is input to a driver IC from a printer main body, a shift register in the driver IC is shifted to a first shift register cell. Are input in order one bit at a time, and this is serially transferred between shift register cells, so that each cell has 1 bit.
The print data for the dot line is stored. Then, in synchronization with the clock signal, the switching element controls energization to each heating element based on the print data stored in each shift register cell. As a result, a predetermined heating element is selectively heated for each dot line, and the heat is transmitted to the thermal paper as a recording medium, so that the heat-sensitive paper portion corresponding to the heated thermal element is colored, and printing is performed. It is formed.

In the printing method described above, for example, in a printing including a ruled line or the like, a specific heating element generates heat more frequently, and as a result, its life may be destroyed in a short time. Therefore, various printing methods have been proposed for suppressing concentration on a specific heating element during printing. For example, JP-A-8-34135, JP-A-8-174
No. 953, Japanese Patent Application Laid-Open No. 10-166638,
By periodically shifting the printing start position of one dot line, the frequency of use of the heating elements is leveled, thereby preventing heat generation from being concentrated on a specific heating element. Also, Japanese Patent Application Laid-Open
In Japanese Patent Application Laid-Open No. 0-272798, a selection circuit for periodically shifting print data by several bits is provided inside the thermal head.

[0005]

However, in the printing method of the prior art as described above, only the concentration on the specific heating element is reduced, and the life of the specific heating element is quickly destroyed. Although it can be prevented, it has no effect on irregular heating element destruction caused by scratching the surface of the head due to entrapment of foreign matter or the like.

FIG. 2 shows an example of printing when a heating element is destroyed.
It will be explained in. FIG. 2A shows a correct print pattern to be printed. Here, if the heating element numbers 10 and 31 are destroyed, printing will be as shown in FIG. In such a case, the correct character cannot be determined,
Misreading occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printing method capable of performing printing without erroneous reading even when a specific heating element is broken.

[0008]

According to a first aspect of the present invention, there is provided a line head having a plurality of print dot elements arranged in a straight line, wherein one line head is provided based on a reference clock. In a line printer that performs printing for each dot line, before or after the printing operation of the line printer, a normal or abnormal state of the printing dot element is measured for each printing dot element, and data creation means for creating printing dot element data, and printing. Element data storage means for storing dot element data, determination means for determining the presence or absence of abnormal dot elements in element data, and original printing for printing by a line printer when there is an abnormal dot in element data Data conversion means for converting data into converted print data based on element data, and output means for outputting converted print data It is characterized in.

According to the second aspect of the present invention, the converted print data is created by inserting data at positions shifted one dot at a time from the data at the position of the abnormal print dot element in the original print data. It is characterized by being performed.

According to the third aspect of the present invention, the converted print data is a combination of the data at the position of the abnormal print dot element and the next data in the original print data. It is created by being inserted in the position next to the position of the printing dot element.

Further, according to the present invention, a counter for counting the printing operation is provided, and when the value of the counter reaches a predetermined value, it is set so as to measure whether the printing dot element is normal or abnormal. It is characterized by the following.

In addition, the invention according to claim 5 is characterized in that it is possible to selectively switch between outputting the signal of the original print data to the print head and outputting the signal of the converted print data to the print head.

According to a sixth aspect of the present invention, a thermal head is used as a print head, and the resistance value of the heating element is measured to determine whether the print dot element is normal or abnormal.

According to a seventh aspect of the present invention, there is provided a notifying means for notifying an operator when the number of abnormal print dot elements in the print element data is equal to or more than a predetermined number or when there are consecutive abnormal print dot elements. And

[0015]

According to the first aspect of the present invention, even if several print dot elements of the head are destroyed, the print pattern can be converted and printed correspondingly.

In the second or third aspect of the present invention, a specific method for converting print data is described, and print data without erroneous reading can be created.

According to the fourth aspect of the present invention, the print dot element can be measured periodically.

According to the fifth aspect of the present invention, optimal printing can be performed when printing characters or when printing graphics.

The invention of claim 6 shows that the present invention is applied to the most effective thermal printer, and it is possible to easily determine whether or not the printing dot element is normal or abnormal.

According to the seventh aspect of the present invention, the timing of head replacement can be notified to the operator in advance.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A printing control method according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a thermal head used for printing control of the present invention and a control circuit thereof. In the thermal head 1, resistors R1 to Rn are connected to a common electrode 2, and each of the resistors R serves as a heating element. Each resistor R is individually connected to the switching elements A1 to An in the driver IC 4 via the individual electrode 3. The output terminal of each switching element A is connected to the STROBE signal of the control circuit 8.
L1 to Ln are latch circuits corresponding to the respective resistors R, and are connected to the LATCH signal. Also, from S1 to S
n is a shift register cell corresponding to each resistor R, and is connected in series to form a shift register. The shift register uses the CLOCK signal and DATA IN
Connected to signal.

The common electrode 2 of the thermal head 1 is connected to a Vh terminal of the circuit section, and is connected to a head power supply 6 via an ammeter 5. The output of the ammeter 5 is an A / D converter 7
Is converted into a digital signal and sent to the control circuit 8. The print control method shown in this example is characterized in that whether or not each heating element operates normally is determined from the resistance value measurement, and print control is performed according to the situation. I do.

First, a constant voltage is applied to only one of the resistors R so as not to generate heat, and the current value is read by an ammeter 5 to determine the resistance value of each resistor R. Ask. When the heating element is destroyed, the resistance value rapidly increases. Therefore, it is possible to determine whether or not the resistance value converted into a digital signal by the A / D converter 7 is larger than a predetermined threshold value. The threshold value is set slightly before the heating element is completely destroyed. If each resistor R does not have a resistance value larger than the threshold value, it is determined that the element is a normal heating element, and “1” is stored in the resistance data memory 9 from the control circuit 8. If the resistance value is larger than the threshold value, it is determined that the heating element is to be destroyed soon, and “0” is stored.

When the above measurement is performed in order from the resistors R 1 to Rn, “1” or “0” becomes n consecutive data which is the total number of the heating elements, and the sequence of the numbers is stored in the resistance data memory 9. You. When all the heating elements can operate normally, the data becomes n consecutive data of "1". If there is at least one "0" in the resistance data, printing is continued. If there is print data in that part, a dot is missing. This example will be described with reference to FIG.

FIG. 2 shows an example in which the word "abcd" is printed by a conventional printing method. FIG. 2A shows an example in which all the heating elements can perform normal printing. FIG. 2B shows an example in which the 10th and 31st heating elements are broken. In the case of the line thermal printer as in this example, the rows of the destroyed heating elements are all missing dots, and the correct word “abcd” cannot be determined. In such a case, an erroneous reading is performed, and therefore, in the related art, it is necessary to replace the head in terms of the head life.

The present invention is intended to prevent such erroneous reading in the related art. After the print data is converted by the DATA conversion circuit 10 using the data stored in the print data memory described above, the DATA IN terminal is used. From the printer to the thermal head 1 to realize printing without erroneous reading.

This method will be described with reference to the flowchart of FIG. When the printer is turned on in Step 1, the printer performs an initialization (initial setting) operation. In the initial stage of the printer, even if all the heat generating elements of the thermal head 1 are normal, if the thermal head 1 is used for a long time, the surface of the thermal head 1 may be scratched or the applied pulse may exceed the withstand pulse number. In some cases, a specific heating element has been destroyed. Therefore, it is determined in Step 2 whether or not a certain timing has been reached, and when the resistance value measurement timing has been reached, the total resistance value of each resistor R is measured in Step 3. The resistance value measuring method is as described above.

After the resistance value is measured, in Step 4, resistance data, which is a sequence data of the total number n of the heating elements, is created. This resistance data is recorded and stored in the resistance data memory 9 in Step 5. At this time, the old data is rewritten to the new data. Thereafter, the counter value is returned to 0 in Step 6. This is because it takes time if the resistance value is measured every time the initialization operation is performed, and the load on the heating element of the thermal head 1 is increased. ing. Once the resistance value is measured and the data becomes new, the counter is reset to measure the next timing.

In Step 7, it is determined whether or not the resistance data in the resistance data memory 9 has "0". "0"
If there is, it means that there is a destroyed heating element.
, It may be erroneously read.
Then, the print data is converted by the DATA conversion circuit.
The converted print data is returned to the head control circuit 8 again. This data conversion will be described later with reference to FIG.

Then, in Step 9, the print data is DA
Output from the TA IN terminal. When a series of printing operations is completed in Step 10, the counter value for determining the next timing of measuring the resistance value is increased by 1 in Step 11.

Data conversion by the data conversion circuit 10 will be described with reference to FIG. The print data is converted by the DATA conversion circuit 10 when the resistance value data is “0”.
If there is. The figure shows resistance value data when the 10th and 31st heating elements are broken. The original print data 100 is data D of "1" or "0".
Is sequence data in which m pieces of the total number of prints are arranged. Here, the value of D when there is a print dot is “1”, and the value of D when there is no print dot is “0”.

In the resistance value data, the 10th and 31st are "0". At this time, in the converted print data 101, “0” is inserted into the 10th and 31st data, regardless of the value of D. Therefore, the data D10 that should be originally placed in the tenth is placed in the eleventh as the next data. Similarly, the eleventh and subsequent data are shifted as data of the converted print data 101 by one. Since the data D30 already has "0" in the 31st, it is entered as the next 32nd data. In this way, the converted print data 101 is sequentially created from the original print data 100 up to the data Dm based on the information of the resistance value data. The total number of converted print data is increased from m to m + X. X is the number of “0” in the resistance value data.

An example of printing the converted print data 101 will be described with reference to FIG. Assuming that the print pattern for printing the original print data 100 is as shown in FIG. 2B, the print pattern for printing the converted print data 101 is as shown in FIG.
(3). There may be a case where a character such as the character "d" has a slightly different shape from that of FIG. 2A, which is an original correct print pattern, but there is no problem in confirming the content. At least, fatal problems such as misreading characters are prevented. Thus, even if several heating elements are destroyed, it is not necessary to replace the head immediately, and the same thermal head can be used for a long time.

As described above, an example of the present invention has been described. However, as a method of converting print data, various methods other than those described above can be considered. An example of another method will be described with reference to FIG.

FIG. 5A shows the original print data 100.
Is normal printing. Here, if the 10th and 31st heating elements are destroyed, the converted print data 102 puts the 10th and 11th data of the original print data 100 into the 11th of the converted print data 102. Similarly, the 31st and 32nd print data of the original print data 100 are entered as the 32nd of the converted print data 102. As a result, the printing is as shown in FIG. 5 (2), and even in this case, printing can be performed to prevent erroneous reading. Further, this method has an advantage that the total number of original print data and the total number of converted print data become the same.

FIG. 5C is an explanatory diagram for explaining a method of converting print data. In the original print data 100, a position where a heating element of a printer is destroyed and printing cannot be performed normally, that is, a position of an abnormal dot element. Is indicated by D10. The converted print data 102 indicates that the data D10 and the data D11 corresponding to the next position of the data D10 are created in the position next to the position of the abnormal dot element. In the above description,
The print control method for automatically converting the print data when the resistance value data has “0” has been described. This is effective from the viewpoint of preventing erroneous reading when printing characters such as "abcd" shown in FIG. 2, but in the case of graphic printing, the graphic shape itself is important, and the shape is changed even if there is a missing dot. Sometimes it is better not to do it. In consideration of such a case, the printer is configured so that the operator can select and print the original print data 100 using a switch or the like even if the resistance value data has “0”.

Measurement of the resistance value of the thermal head heating element is as follows.
Although an example is shown in which a counter for measuring at a certain timing is provided, an operator may manually measure the resistance value at an arbitrary time without providing a counter. For example, ECR
If the printer suddenly enters resistance measurement,
The receipt issuance operation may be interrupted, causing an adverse effect such as making the customer wait. In such a case, the measurement may be performed by a manual switch at a preparation time or the like before the store is opened.

Further, by using the resistance value measurement of the heating element shown in this embodiment, it is possible to notify the operator of the time for replacing the thermal head. For example, the number of "0" in the resistance data is counted, and when "0" is larger than a predetermined number or "0" is continuous, a display prompting to replace the thermal head is performed. it can.

As described above, the embodiments of the present invention have been described as applied to a thermal printer. In the case of a line thermal printer, once a printed dot element is destroyed, it cannot be recovered by cleaning or the like. For this reason, the present invention is more effective for two reasons that determination of normal or abnormal can be made extremely easily only by measuring the resistance value. However, the present invention is not necessarily limited to thermal printers, and can be widely applied to various printers such as laser printers and line inkjet printers as long as the normal / abnormal of the print dot elements of the printer can be determined for each element. it can.

[0040]

As described above, according to the present invention, according to the first aspect of the present invention, the print data is converted when the print dot element has an abnormality. Even if several elements are destroyed, the printing pattern can be converted and printing can be performed correspondingly, and the printer can be used continuously without replacing the expensive head in the printer immediately. The product life can be extended significantly. Further, even if the printing dot element is destroyed before the end of the product life due to irregular causes such as scratches, it is possible to print without erroneous reading.

Further, if the print data is converted by the method described in claim 2 or 3, a print pattern free from erroneous reading can be easily created.

It may take time to measure the state of the print dot element every time, but if the counter is set to measure the print dot element periodically at a certain timing, There is no delay in normal printing operation.

Further, if there is a means for selecting output data as described in claim 5, optimal printing can be performed in any case of printing characters and graphics.

The present invention is particularly effective when applied to the thermal printer according to the sixth aspect. Claim 7
If the notification means described above is provided, the timing of head replacement can be notified to the operator in advance. Even in this case, the head can be used even if the head is broken by several dots in the present invention, so the head replacement timing is longer than in the conventional printer.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a thermal head and a control circuit thereof according to the present invention.

FIG. 2 is a print pattern diagram showing a conventional print example and a print example of a print control method according to the present invention.

FIG. 3 is a flowchart of a print control method according to the present invention.

FIG. 4 is an explanatory diagram showing data conversion by the data conversion circuit of the present invention.

FIG. 5 is an explanatory diagram illustrating data conversion according to another embodiment of the present invention, and a print pattern diagram illustrating a print example thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal head 4 Driver IC 5 Ammeter 7 A / D converter 8 Control circuit 9 Resistance data memory 10 DATA conversion circuit An Switching element Ln Latch circuit Sn Shift register cell 100 Original print data 101 Conversion print data

Claims (12)

[Claims] 1. A line printer equipped with a line head having a plurality of print dot elements arranged in a straight line and performing printing by using the line head for each dot line, wherein the line printer is used for printing. In advance, a normal or abnormal state of the print dot element is measured for each of the print dot elements, and data creating means for creating print dot element data; and an abnormality in the print element data created by the data creation means. Judgment means for determining whether or not a dot element is present, When the determination means determines that an abnormal dot exists in the print element data, original print data to be printed by the line printer, Data conversion means for converting the print element data into converted print data based on the print element data; Line printer, characterized in that it comprises an output means for outputting the converted print data to said line head. 2. The data conversion means according to claim 1, wherein said converted print data is shifted from the original print data to a position sequentially shifted by one dot from data corresponding to a position of an abnormal dot element in said print element data. 2. The line printer according to claim 1, wherein the line printer is created by inserting data. 3. The data conversion means converts the converted print data into data corresponding to a position of an abnormal dot element in the print element data and data corresponding to a position adjacent thereto in the original print data. 2. The line printer according to claim 1, wherein the data is created by putting data obtained by adding the data to a position next to the position of the abnormal dot element. 4. The printing apparatus according to claim 1, further comprising a counter for counting a printing operation, wherein when the value of the counter reaches a predetermined value, the data creation unit measures whether the printing dot element is normal or abnormal. The line printer according to any one of claims 1 to 3. 5. A switching means for selectively switching between output of the signal of the original print data to the line head and output of the signal of the converted print data to the line head. Item 5. The line printer according to any one of Items 1 to 4. 6. A notifying means for notifying an operator when the number of abnormal print dot elements in the print element data is equal to or more than a predetermined number, or when there is a continuation of abnormal print dot elements. The line printer according to claim 1, wherein: 7. A printing method for a line printer, comprising a line head having a plurality of print dot elements arranged in a straight line and performing printing using the line head for each dot line. Before printing, beforehand, the normal or abnormal of the print dot element is measured for each of the print dot elements, a data creation step of creating as print dot element data, and the print element data created by the data creation step A determining step of determining whether or not an abnormal dot element exists in the print data; an original print to be printed by the line printer when the determining step determines that an abnormal dot exists in the print element data; A data conversion step of converting data into converted print data based on the print element data; and the data conversion step. Thus converted printing method for a line printer, characterized in that and an output step of outputting the converted print data to the line head. 8. The data conversion step includes: converting the converted print data to a position in the original print data that is sequentially shifted by one dot from data corresponding to the position of the abnormal dot element in the print element data. 8. A printing method for a line printer according to claim 7, further comprising a step of creating by adding data. 9. The data conversion step includes converting the converted print data into data corresponding to a position of an abnormal dot element in the print element data in the original print data and data corresponding to a position adjacent thereto. 8. The line printer according to claim 7, further comprising a step of creating data by combining the data with the position of the abnormal dot element. 10. The data generating step includes a counter for counting a printing operation, and when the value of the counter reaches a predetermined value, measures whether the printing dot element is normal or abnormal. 10. The printing method of the line printer according to any one of items 7 to 9. 11. A switching step for selectively switching between outputting the signal of the original print data to the line head and outputting the signal of the converted print data to the line head. Item 11. The printing method of the line printer according to any one of Items 7 to 10. 12. A notifying step for notifying an operator when the number of abnormal print dot elements in the print element data is equal to or more than a predetermined number or when there is a continuous abnormal print dot element. The printing method of a line printer according to claim 7, wherein