JPS61241169A - Thermal recorder - Google Patents

Abstract

PURPOSE:To enable high-speed recording and image recording to be performed with uniform density and high quality, by correcting driving time or driving power for heating elements of a recording head on the basis of the total number of recording dots in one section. CONSTITUTION:The thermal recorder performs recording in a line by selectively driving at a predetermined interval a plurality of heating elements for recording a predetermined dots in a row in a sub-scanning direction while moving the elements in a main scanning direction. In the recorder, for each of sections formed by dividing a line on the basis of a predetermined dot rows in the sub- scanning direction, data for correcting heating pulse width for the heating elements of the recording head 4 are formed, and are outputted to a comparing part 107. In this case, dividing of a line is conducted through a row-counting part 104. Data thus inputted are compared with a reference value for correction inputted from a reference-generating part 108 by the comparing part 107, and according to the results of comparison, the heating pulse width for the heating elements of the head 4 is corrected by a pulse width controlling part 109 through a head driver 110.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal recording device, and more specifically, the present invention relates to a thermal recording device, and more specifically, a thermal recording device that records a predetermined number of dots in one row in the sub-scanning direction while moving a plurality of heating elements in the main scanning direction. The present invention relates to a thermal recording device that records one line by selectively driving at predetermined intervals.

[Summary of the Disclosure] This specification and the drawings describe a means for dividing one line into a plurality of sections, and a method for determining the drive time of a heating element or By providing means for obtaining data for correcting driving power and means for performing the correction according to the data, and performing the correction according to the data, it is possible to record images at high speed and with uniform density and high quality. This paper discloses a technology that enables

[Prior Art] In a recording device of the type described in the industrial application field, such as a thermal printer of a heat-sensitive type or a thermal transfer type, a voltage is applied to a heating element equivalent to a resistance provided in a thermal head of a recording head. Since recording is performed using the heat generated by the head's heat generating elements, overheating of the head's heat generating elements poses the greatest problem in order to perform high quality recording with uniform density.

To deal with this, conventional recording devices of this type use a temperature sensor such as a thermistor to detect the ambient temperature, and depending on the detection result, pulses of voltage (hereinafter referred to as heat pulses) are applied to the heating element of the head. Arrangements for controlling width are known.

Another known configuration is that when dots are recorded successively in the paper width direction (main scanning direction), the heat pulse width is narrowed by a certain amount for the second and subsequent dot recordings.

Furthermore, as another configuration, especially in the case of image recording, a configuration is known in which the number of heated (recorded) dots is counted for each recording of one row in the sub-scanning direction, and the heat pulse width is controlled according to the counting result. There is.

[Problems to be Solved by the Invention] In the first conventional configuration described above, since the response speed of the temperature sensor is slow, there is a problem in that it is difficult to cope with the speed of heat storage in the heating element.

Further, the second configuration has a problem in that when a large number of dots to be recorded are consecutive in the main scanning direction, the heat storage of the heating element is too large to cope with this.

Although these problems are true even in the case of character recording with a relatively low dot duty, they become particularly serious problems in the case of image recording with a relatively high dot duty.

On the other hand, the third configuration can handle image recording, but this configuration requires a lot of control time because it counts the number of heat dots for each row of recording and controls the heat pulse width according to the counting results. Unable to respond to high-speed carriage movement. Also, the heat pulse width is not changed every time one column is counted, but the counting results are stored in memory.
Since the pulse width is corrected at a certain point in time, there is a problem in that there is a time loss.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a thermal recording device of this type that can record images at high speed and with uniform density and high quality. The purpose is to

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a plurality of heating elements for recording a predetermined number of dots in one row in the sub-scanning direction are moved in the main scanning direction and selectively driven at intervals of 1
In a thermal recording device for recording rows, means for dividing the one row into a plurality of sections, and means for obtaining data for correcting the driving time or driving power of the heating element from the total number of recorded dots within one of the sections; A configuration is adopted in which a means for performing the correction according to the data is provided.

[Operation] In the configuration of the control circuit of the thermal printer shown in FIG. 1, print data is input to the control unit 10 from an external host system (not shown) one column at a time in the sub-scanning direction via the interface 100. The recorded data is then stored in the control unit lO.
The recording head 4 is guided directly to the head driver 110, which drives the recording pad 4 and is also guided to the dot number counting section 102. And dot number counting section 102
, vertical weighting is in section 103. Column number counting section 104. The lateral weighting is performed by dividing one row into a predetermined number of dot rows in the sub-scanning direction through the section 105 and the data integration section 106, and calculates the heat pulse width of the heat generating element of the rad 4 from the total number of recording dots in each section. Data is created to correct the
It is output to comparison section 107. In this case, the above-mentioned one-row division is performed via the column number counting section 104.

Now, the comparison unit 107 compares the input data with the correction reference value input from the reference generation unit 108,
In accordance with this comparison result, the pulse width controller 109 corrects the heat pulse width of the heating element of the recording head 4 via the head driver 110.

[Embodiments] Hereinafter, details of embodiments of the present invention will be described with reference to the attached drawings. Here, a thermal printer that performs thermal recording using thermal recording paper is used as an embodiment, and the following description assumes that image recording is performed.

FIG. 2 shows an outline of the mechanical configuration of this embodiment.

As shown in the figure, a carriage 3 is slidably provided on a guide shaft 2 installed on the printer main body l, and a recording head 4 configured as, for example, a known thermal head is mounted on the carriage 3. It is mounted and faces the recording surface of a recording medium (thermal recording paper) set in the printer main body l in contact with a platen (not shown).

During recording, after the thermal head 4 is brought into pressure contact with the recording medium 5 by driving of a driving means (not shown), the carriage 2 is similarly driven in the main scanning direction shown by the arrow S by the driving means (not shown), and at the same time, the thermal head 4 is driven by the driving means (not shown). Heat pulses are selectively applied to a predetermined number of heating elements arranged in a row in the sub-scanning direction indicated by the arrow F on the front surface, and heat pulses are selectively applied every time the heating elements are moved at a predetermined interval, thereby generating heat, as shown in FIGS. 3 and 4, for example. Recording is performed in a dot matrix pattern.

In FIGS. 3 and 4, the dots 6 recorded are shown as black circles, and the dots 7 that are not recorded are shown as white circles. 24
Dots are selectively recorded in multiple rows at a predetermined pitch in the main scanning direction, thereby recording an image in a dot pattern.

Next, the configuration of the control circuit of this embodiment is shown in FIG.

In the figure, reference numeral 100 indicates an interface, and via this interface, a control section indicated as a whole by reference numeral 10 is connected to a host device such as a computer (not shown).

The control unit IO is a known CP that controls the entire printer.
It is composed of a microcomputer consisting of a central processing unit (U), a ROM (read only memory), and a random access memory (RAM), and controls the recording head 4 via a head driver 110. Although omitted, the driving means for the carriage 2, the feeding means for the recording medium 5, the operation panel section, etc. are controlled through other drivers, and the control section 10 has the following components indicated by reference numerals 101 to 109. It is composed of microcomputer hardware or software.

Reference numeral 101 denotes a printer control unit, which controls the drive means for the carriage 2, the feeding means for the recording medium 3, the operation panel unit, etc., and receives data input from the host device via the interface lOO. All control data other than recording data is stored in this printer control unit 1.
01, and the printer control unit 101 controls each of the above-mentioned units accordingly.

On the other hand, among the input data, print data is input one column at a time in the vertical direction (sub-scanning direction), is directly guided by the head driver 110 via a latch (not shown), etc., and is recorded by the head driver 110 in accordance with this. As the head 4 is driven, it is guided to a vertical heat dot number counting section (hereinafter abbreviated as the dot number counting section) indicated by the reference numeral 102,
Heat pulse width control related to the present invention is performed by the configuration below this dot number culnt member.

The dot number counting section 102 counts the number of heat dots (the number of recorded dots) n based on the input recording data for one column, and outputs the result to the vertical weighting section 103. Furthermore, every time one column is counted, data necessary for counting the number of recording columns is output to the column number counting section 104.

The vertical weighting unit 103 uses the input heat dot an
The weighting, which is set in stages in relation to the size of the number n of heat dots, is done by multiplying the coefficient by the corresponding one to obtain the @ k n. The M! 1k n is output to section 105 for horizontal weighting.

Here, the relationship between n and k is set, for example, as shown in the table in FIG.
is divided into 13 categories according to their size, and a coefficient k is set for weighting each category. For example, if n = 5, then = -2
If n=21, then n=8.

On the other hand, the previously mentioned column number counting section 1-04 cyclically counts the number of counts of the dot number counting section 102 up to a predetermined number, in this case up to 8, thereby converting one row into the number of dot columns in the sub-scanning direction. The ordinal number of the column is divided into a predetermined number (in this case, 8 columns) and indicates the number of the record column in which the number of heat dots was counted by the dot number counting unit 102 in one section;
It is used to count. Here, one division mentioned above is called one box, and the column number counting section 104 outputs the above counted data to the horizontal weighting section 105, and at the same time,
When the counted value reaches the aforementioned predetermined number, in this case 8, data indicating this is output to the data integration section 106.

The horizontal weighting part tOS is the vertical weighting part 103, and the plurality of weightings set in relation to the above-mentioned product kn inputted from the column number counting part 104 and the above-mentioned ordinal number inputted from the column number counting part 104 is a coefficient 1. Multiply the corresponding one of them, and the product jl
This is to obtain kn, and the weighting is made up of a storage means that holds a coefficient 1, and an arithmetic means that performs the multiplication.

In this case, the relationship between the column ordinal number and the weighting coefficient 1 is set as shown in the table of FIG. 6, for example.

Then, the lateral weighting section 105 converts the above product kn into correction data N,=J, of the m-th column for heat pulse width correction related to the present invention.

It is output to the data integration unit 106 as a.

The data integration unit 106 sequentially integrates the correction data N for one column input sequentially from the first column to the eighth column to obtain the correction data N for the l box.

The data N is output to the comparison unit 107 in response to the output from the column count unit 104 indicating that the number of boxes has been reached.

After this output, data N in the data integration section 106 is cleared.

The comparison unit 107 compares the input correction data N with a reference value NREF for correction.
F is input from the reference generation section 108.

The reference generation unit 108 includes a storage means for holding a plurality of reference values NREF, and an input means for selecting one of the plurality of reference values NREF and outputting it from the storage means. - Consists of switches etc. provided on the operation panel shown. In addition, the above reference value NRE
F is set, for example, as shown in FIG. 7 in accordance with the mode such as recording density. In this case of Fig. 7, mode No. 1 to 3
The reference values NREF are for dark, normal, and high recording densities, respectively.
Corresponding to the maximum value, standard value, and minimum value of the thin or heat pulse width, the reference value 8 days EF of mode NO4 corresponds to a special recording medium, and these were determined experimentally.

The reference value NRE F outputted to the comparator 107 is compared with the correction data N described above.
This is done by dividing by F and finding the integer quotient α,
Specifically, this is performed by repeatedly subtracting NREF from N until NREF cannot be subtracted from N (until the difference in the result of subtraction <N, . . . F), and counting the number of subtractions.

That is, (α+1)NREF>N≧αNREF or N
REF>N-αNRE Find α for which F≧0 holds true.

However, α is an integer of α≧1.

Then, the comparator 107 converts the obtained α into the pulse width controller 109.
At the same time, the remainder of the division mentioned above, that is, N
-αNREF is weighted by a predetermined one box by multiplying it by a coefficient.For example, if the coefficient is 1/2, then 1/
2(N-αNRIEF) and is carried over to the integration unit 10 for creating correction data in the next box.
Return to 6 and add.

Next, the pulse width control unit 1 receives α from the comparison unit 107.
09 controls the width of the heat pulse applied to each heating element of the recording head 111 via the driver 110. When α is input, the width of the heat pulse for the next 8 columns of boxes is shortened by αgs. .

Next, heat is generated by the configuration of the control unit IO as described above.

The pulse width correction operation will be explained with reference to FIG. Note that FIG. 8 is a flowchart showing the procedure of heat pulse width control by the control unit IO.

The control shown in FIG. 8 is started at the start of recording.

First, in step Sl, one row of heat (
Recording) Count the number of dots n.

Next, in step S2, the vertical weighting unit 103 performs vertical weighting, that is, multiplies the number n of heat dots by the weighting coefficient, and obtains the product kn.

Next, in step S3, the horizontal weighting unit 105 weights the result kn in the m-th column in the horizontal direction, that is, multiplies the product kn and the weighting coefficient 1, and the product N, = no kn is calculated, and this product N1 is integrated by the integration unit 106.

Next, in step S4, if the integration has reached 1 box via the column number counting section 104, the process returns to step 51 and repeats the operations from steps 51 to S4, and when it reaches 1 box, the process advances to step S5.

In step S5, the comparison unit 107 described above compares the correction data N with the reference value NRE F to determine whether or not to perform heat pulse width correction. That is, α is determined by the above-described division, and whether or not correction is to be performed is determined based on whether α is obtained.

If α is obtained and correction is to be performed, the process advances to step S6, and after the pulse width control unit 109 shortens the pulse width of the next box by αgs, the process advances to step S7, where α cannot be obtained and correction is to be performed. If not, the process directly advances to step S7.

In step S7, the comparator 107 multiplies the above-mentioned division remainder N-αNRE F by the weighting coefficient for one box, and this product is sent to the data integration unit 106 to create correction data for the next box. Return it as a carryover.

After that, return to step St and repeat the above operation.
That is, in the next box, the sum of the data carried over from the previous box and the new correction data N is compared with the reference value NREF.

Next, as specific examples of the heat pulse width correction according to the present embodiment as described above, a case where the recording for 1 pox is as shown in FIG. 3 and a case as shown in FIG. 4 will be described.

In the case of Fig. 3, the correction data N, = j2kn for each column is in the 1st column LX 10 X24 = 2402nd column 2X 5 X20 = 2003rd column
3X 3 X16= 1444th column 4
X lX12= 485th column 5X(-
1)X 8=-406th column 9X(-2)X
5= -907th column 15X (-4)X
2= -1208th column 28X (-5)X O=
Correction data N = 1 box from 0 or more
It is 382. N is compared with a reference value NRE_F, and the pulse width is changed based on the result. For example, NRE F=
If it is 3212, α cannot be obtained, so the pulse width is not changed.Then, this N is multiplied by a correction coefficient for each box and carried over to create correction data for the next box.For example, the correction coefficient for each box is 0. If is 1/2, then l/
Carry 2N=191 to the next box.

On the other hand, in the case of Fig. 4, the correction data N in each column is 1st column IX (-5) X O = -52nd column
2X(-4)X 2=-163rd column 3
X(-2)X 5=-304th column 4X(-
1)X 8=-325th column 5X lX
12 = 606th row 9X 3 X16
= 4327th column 15X 5 X20=
15008th column 28X 10 X24= 6
Correction data for 1 box from 720 or more N = 8629
It is. Here, if NRεF=3212, N RE p
> N-αNRεF≧O holds true and α = 2, so set the heat pulse width when recording the next box to 2.
Shorten by 1Ls.

Also 1/2 (8829-3212X 2) = 110
11 for creating correction data in the next box from 2.5.
Carry forward 02.

As described above, in this embodiment, the total number of recorded dots for each l box, in which one row is divided into a predetermined number of dot rows in the sub-scanning direction, is processed by weighting in the main-scanning direction and the sub-scanning direction. The heat pulse width correction data is created using the heat pulse width correction data, and this data is compared with the correction base/preparation, and pulse width correction is performed for each box according to the comparison results. It can cope with the speed of heat accumulation in the heating element of the head, and it can also cope with the magnitude of heat accumulation when recording dots are continuous in the main scanning direction. Furthermore, since the correction process is performed for each box at once, the correction process time can be significantly shortened. Therefore, such correction processing allows high-quality image recording to be performed at high speed and with uniform recording density.

In the above description, the l-box has eight columns, but the number of columns of the l-box is of course not limited to this. In addition, the heat pulse width, that is, the driving time of the heating element was controlled by comparing the correction data of one box with the correction reference value.
The drive voltage or current may also be controlled. Further, in the above description, it is assumed that image recording is performed, but it goes without saying that character recording can also be performed with the above-described configuration.

[Effects of the Invention] As is clear from the above description, according to the thermal recording apparatus of the present invention, the recording head can be calculated based on the total number of recording dots in one division in which one row is divided into a predetermined number of dot rows in the sub-scanning direction. Data for correcting the driving time or driving power of the heating element is obtained, and the above correction is performed according to this data, which has the excellent effect of allowing high-speed recording of 9 images with uniform density and high quality. is obtained.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention, and FIG. 1 is a block diagram of a control circuit of a thermal printer according to the embodiment, FIG. 2 is a perspective view showing the mechanical configuration of the printer, and FIGS. Figure 4 is an explanatory diagram of dot recording, Figure 5 is a table of coefficients for vertical weighting, Figure 6 is a table of coefficients for horizontal weighting, Figure 7 is a table of correction reference values, FIG. 8 is a flowchart showing the control procedure for pulse width correction. l... Printer body 2... Guide shaft 3... Carriage 4... Recording head 5... Recording medium
lO...Control unit 102...Dot number counting unit 103...Vertical direction weighting unit 104...Column number counting unit 105...Horizontal direction weighting unit 106...Data integration unit 107 ...Comparison section 108...Reference generation section 10
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Claims (1)

[Claims] In a thermal recording device that records one row of a predetermined number of dots in the sub-scanning direction by selectively driving a plurality of heating elements at predetermined intervals while moving in the main-scanning direction to record one row. a) means for dividing said one row into a predetermined number of said columns; b) means for obtaining data for correcting the driving time or driving power of the heating element from the total number of recorded dots within one of said divisions; c) A thermal recording device characterized by comprising means for performing the correction according to the data.