JPH03253355A - Recorder - Google Patents

Abstract

PURPOSE:To remove variation in recording density by heat accumulation of an element or the like by a method wherein a relation between an image data and recording pixel density by the element is corrected successively by a calculation result of a thermal influence calculation means, a stored data of a memory means, and a calculation result of a simultaneously driving element number calculating means. CONSTITUTION:A first and last transient correction part 12 corrects a pulse number data from an adjacent history correcting part 11 by a mean value of the pulse number data to a noticed element and elements around that in order to correct influences on the noticed element of heat accumulation temperature of a thermal head base due to heating by past tens lines content image data of the noticed element and due to heating of tens elements around the noticed element. The pulse number data from this first and last transient correction part 12 is corrected by a resistant value data independently measured of each element of the thermal head preliminarily stored in the memory with a resistance correcting part 13, is converted to a pulse form data suitable for the thermal head 15 with a head driving part 14, and is transmitted to the thermal head 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording apparatus that thermally records an image using a head such as a thermal head or an energized recording head.

[Conventional technology]

Conventionally, in this type of recording apparatus, in a recording apparatus in which a thermal head having an element consisting of a plurality of heating resistors arranged in a line is driven by binary image data, the heat storage state of each of the elements is As shown in Figure 29, the element (hereinafter referred to as the attention element)
A plurality of pixels D1 to D2□ around the pixel Do recorded by (hereinafter referred to as the pixel of interest) Do, that is, the pixel of interest. From line Ll containing
Each pixel D1 around the pixel of interest in the range up to 6
~D21 is calculated by weighting and adding data according to the position of each pixel D~D21, and by correcting the image data of the pixel of interest with the result, the density of the pixel of interest due to the heat storage state of the element is calculated. A method for correcting the influence is known from Japanese Patent Laid-Open No. 131262/1983.

[Problem to be solved by the invention]

In the recording apparatus described above, the heat storage state of each element of interest is determined by adding the image data of each of the pixels D to D21 surrounding the pixel of interest D0 with weighting according to the position of each pixel D□ to D21.

If the image data is binary data, pixel D1
The amount of information in the image data of ~D21 is small and the heat storage state of the element can be calculated, but if the image data is multi-valued and a multi-gradation image is to be recorded, the image data of pixels D2-D2□ Not only that but also line L
Since the image data of pixels in front of 6 affects the density of the pixel of interest, it becomes necessary to calculate the heat storage state of the element from these image data, and the amount of information increases considerably, making the device larger and more expensive. It is almost impossible to implement.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and to provide a recording apparatus that has a simple configuration and is capable of recording multi-tone images without fluctuations in recording density due to heat accumulation in each element.

[Means to solve the problem]

To achieve the above object, the present invention makes the plurality of elements in a head having a plurality of elements arranged in a line generate heat in accordance with binary image data to record pixels line by line. In the recording device, a thermal influence calculation for calculating the influence on the recording pixel density due to the thermal influence of surrounding elements on the element that records a pixel among the plurality of elements and the heat accumulation of the element that records two pixels. storage means for storing data of the measured resistance values of each of the plurality of elements or recording density correction data of each recording position corresponding to the random positions of the plurality of elements; a simultaneously driven element number calculation means for calculating the number of simultaneously driven elements in the plurality of elements; and a calculation result of the thermal influence calculation means that sequentially calculates the relationship between the image data and the recorded pixel density by the elements; Stored data in the storage means.

and a correction means for correcting based on the calculation result of the simultaneously driven element number calculation means.

[For production]

Thermal influence of surrounding elements on the element that records pixels among multiple elements.

The influence on the recorded pixel density due to the heat accumulation of the element that records the pixels is calculated by the thermal influence calculation means, and corresponds to the data of the individual measured resistance values of the plurality of elements or the individual positions of the plurality of elements. The recording density correction data for each recording position is stored in the storage means. The simultaneously driven element number calculation means calculates the number of simultaneously driven elements in a plurality of elements from the image data, and the correction means sequentially calculates the relationship between the image data and the recorded pixel density by the elements by the thermal influence calculation means. The result is corrected using the data stored in the storage means and the calculation result of the simultaneously driven element number calculation means.

〔Example〕

FIG. 1 shows an embodiment of the invention.

In this embodiment, pixels are recorded one line at a time by heating the plurality of elements in a thermal head head having elements made up of a plurality of heating resistors arranged in a line in accordance with multivalued image data. It is a recording device that can be used to record images. When multivalued image data is sent, the adjacent history correction unit 11 calculates the thermal influence of a plurality of nearby elements surrounding the element of interest (the element that records pixels) and the past lines of the element of interest. Calculate the effect on the recorded pixel density due to heat accumulation due to the image data of The fall correction unit 12 calculates the influence of the heat storage temperature at the base of the thermal head on the element of interest due to the heat generated by the past several dozen lines of image data of the element of interest and the heat generation of several dozen elements surrounding the element of interest. In order to perform the correction, the pulse number data from the adjacent history correction unit 11 is corrected using the average value of the pulse number data for the element of interest and its surrounding elements. This pulse number data from the rising/falling correction section 12 is corrected in the resistance correction section 13 using the data of the individually measured resistance value of each element of the thermal head, which is stored in advance in the memory. The data is converted into pulse-form data DATA suitable for the head 15 and transferred to the thermal head 15. In addition, the element number correction section 16 is connected to the resistance correction section 13.
The number of elements of the thermal head that are simultaneously driven is calculated from the pulse number data from , and the width of the strobe pulse STH from the strobe circuit 17 to the thermal head 15 is changed based on the calculation result.

FIG. 2 shows the configuration of the adjacent history correction section 11.

The adjacent correction unit 18 includes a shift register 19 and a correction amount ROM2.
0, an adjacent correction ROM 21 and a γ correction ROM 22, and the history correction section 23 consists of a heat storage calculation section 24 and a history correction ROM 25.

The adjacent correction unit 18 receives multivalued image data from the outside in synchronization with the synchronization clock CLK, and latches this image data into the first stage of the shift register 19. When the next multi-gradation image data is input, the shift register 19 shifts the image data latched in the first stage to the second stage, and latches the external image data in the first stage. Similarly, each time multi-gradation image data is input from the outside, the image data is latched into the first stage of the shift register 19, and the image data latched into the first stage of the shift register 19 is transferred to the shift register. The image data latched in the second stage of the shift register 19 is shifted to the third stage of the shift register 19, and the image data latched in the third stage of the shift register 19 is shifted to the second stage of the shift register 19. The image data is shifted to the fourth stage of the shift register 19, and the image data latched in the fourth stage of the shift register 19 is shifted to the fifth stage of the shift register 19.

The image data X latched in the third stage of the shift register 19 is converted by the γ correction ROM 22 into pulse number data P indicating the density level as the number of pulses.

The first stage, second stage, and fourth stage of the shift register 19.

The image data latched in the fifth stage, that is, two image data before and after the image data X latched in the third stage of the shift register 19, are stored in the correction amount ROM 20 constituting the calculation means, and the two before and after the image data X latched in the third stage of the shift register 19 are stored in the correction amount ROM 20 constituting the calculation means. The pulse number data P from the γ correction ROM 22, which is converted into data H of the amount of thermal influence by each element, is converted into correction amount RO by the adjacent correction ROM 21 constituting the correction means.
It is corrected by the magnitude of the thermal influence amount data H from M20, and converted into appropriate pulse number data R such that the thermal influence of the two elements before and after the element of interest is eliminated.

The heat storage calculation unit 24 calculates data on the amount of heat storage of the element of interest and the elements before and after it as correction data from the pulse number data R from the adjacent correction ROM 21. In the history correction ROM 25 constituting the correction means, appropriate pulse number data for the heat storage amount of the element of interest and the elements before and after it is written in advance as a table.
The pulse number data R from the adjacent correction ROM 21 is corrected in the history correction ROM 25 by the correction data from the heat storage calculation unit 24, so that the thermal influence of the heat storage amount of the element of interest and the elements before and after it on the element of interest is eliminated. corrected (converted) to pulse number data.

FIG. 3 shows the configuration of the heat storage calculation section 24.

The pulse number data R from the adjacent correction ROM 21 is alternately written line by line into the line memories 26 and 27 constituting the delay means. The line memories 26 and 27 perform a toggle operation for each line, so that write operations and read operations are switched, and when one is performing a write operation, the other is performing a read operation. In the read operation, the line memories 26 and 27 read out the pulse number data Xj of the pixel of interest one line before, and the pulse number data Xj-3 to Xj-1, Xj+1 to Xj+3 of three pixels before and after that, and these pulse number data are respectively multiplied by weighting coefficients a-3 to a+3 in the calculation unit 28 and added. Here, a. is a weighting coefficient for the pulse number data of the pixel of interest one line before, a-3 to a-1 is a weighting coefficient for the pulse number data of a pixel 3 to 1 before the pixel of interest one line before, al"a3 is the weighting coefficient for the pulse number data of the pixel 1 to 3 after the pixel of interest l lines before, and is Σ ai = 1 1 knee 3. The data AD from the calculation unit 28 is AD = Σ ai
XXj+i i;-3, which is the heat storage amount data based on the pulse number data of one line before for the element of interest and three elements before and after it. This data AD is summed with the data GD from the attenuation ROM 30 in an adder 29 which constitutes a calculation means, and the line memory 31.3 which constitutes a delay means.
2, one line at a time is written alternately. The line memories 31 and 32 perform a toggle operation for each line, so that write operations and read operations are switched, and when one is performing a write operation, the other is performing a read operation. In the read operation, the line memories 31 and 32 read out the calculation data Xj+i' of one line before and the calculation data Xj+i'-1 and Xj+i'+1 before and after it, and these calculation data are weighted in the calculation unit 33. The coefficients a-1' to al' are respectively multiplied and added.

Here, a01 is a weighting coefficient for the calculation data one line before, a-1', a◆1' is a weighting coefficient for the calculation data one line before and after the calculation data one line before, and Σ ai '=1 i=-1, the data from the calculation unit 33 becomes Σ a i'
) is multiplied and input to the adder 29. The data AD from the calculation unit 28 is the heat storage amount data based on the pulse number data of the l line before for the element of interest and three elements before and after it.
is inputted to the attenuation ROM 30 through the line buffer 31 or line buffer 32 and the arithmetic unit 33.
Data on the amount of heat storage can be obtained based on the pulse number data of two lines before each element. Furthermore, this data passes through the adder 29 and is input to the attenuation ROM 30 through the line buffer 31 or line buffer 32 and the arithmetic unit 33, so that the attenuation ROM 30 receives pulse number data three lines before for the element of interest and five elements before and after it. Similarly, the data from the attenuation ROM 30 circulates through the adder 29, line buffer 31 or line buffer 32, arithmetic unit 33, and attenuation ROM 30, thereby determining the amount of heat stored according to the previous pulse number data for each element. data is obtained. As a result, the data from the adder 29 is input to the history correction ROM 25 as correction data, and the adjacent correction RO
The pulse number data R from M21 is corrected by the amount of heat storage according to the previous pulse number data for each element, and the element of interest records pixels without being affected by its own heat storage and heat storage of other elements. In this case, the element of interest will no longer be affected by the heat storage of other elements, but the heat storage of other elements will expand by two each time the previous line is reached, and the previous heat storage will be included infinitely. It will be.

FIG. 4 shows the configuration of the rising/falling correction section 12.

The pulse number data D from the adjacent history correction section 11 is added to the calculation data D' from the A-1 multiplication circuit 34 by an adder 35, and divided by 1/A by a 1/A calculation ROM 36.

Here, A is a predetermined coefficient. ROM3 for 1/A calculation
The data AV from 6 is subtracted by the subtraction unit 37 from the pulse number data D from the adjacent history correction unit 11, resulting in C=D−A.
V, and the pulse number data D from the adjacent history compensator 11
is corrected by the rising/falling correction ROM 38 using the data C from the subtractor 37, and becomes appropriate pulse number data E. In this rising/falling correction ROM 3g, appropriate pulse number data for the data C from the subtraction section 37 is written in advance as a table, and the pulse number data D from the adjacent history correction section 11 is stored in the form of a table, for example, E=D- Convert to F-C data. Here, F is a predetermined coefficient.

In the line memories 39 and 40, the data AV from the 1/A operation ROM 36 is written alternately for each line, and if one is in the writing operation, the other is in the reading operation, and the pulse number data D becomes 1. The data Yj before the line and the adjacent data Yj-1 and Yj+1 before and after it are read out alternately. The data YJ-LYj+Yj+1 alternately read from the line memories 39 and 40 is sent to the adder circuit 41.
Then, the weighting coefficient b-2°bO+b+ is multiplied by vignetting and added, resulting in X b 1-xj+i. However, Σb
i=1. The data from the adder circuit 41 is multiplied by A-1 by the A-1 multiplier circuit 34 to become calculation data D'.

Therefore, the data C from the subtractor 37 is data obtained by smoothing the pulse number data D, and the data E from the rising/falling correction ROM 38 is such that, for example, in the case of a solid part, the rising part is reduced from a large positive value. It is corrected so that the falling part increases by more than O or a small value.

Therefore, the pulse number data D is corrected for tens to hundreds of lines, making it possible to correct density fluctuations of about a hundred lines. As a result, the solid portion recorded by the thermal head 15 will have an appropriate density from the beginning, and the trailing phenomenon of density will not occur even in the falling density portion, improving image quality.

FIG. 5 shows the configuration of the resistance correction section 13.

The resistance correction section 13 includes a resistance value detection section 42, an analog/digital (A/D) conversion section 43, a memory 44, and a data correction section 45. When the power is turned on, the resistance value of each element of the thermal head 15 is detected by the resistance value detection unit 4.
2, is A/D converted by the A/D converter 43, and is stored in the memory 44. This data is in memory 4
4 is read out corresponding to the pulse number data from the rising/falling correction section 12, and the pulse number data from the rising/falling correction section 12 is corrected by the data correcting section 45 using the data from the memory 44. , correction is made so that fluctuations in recorded pixel density due to variations in resistance values of each element in the thermal head 15 are eliminated.

FIG. 19 shows the circuit configuration of the thermal head 15.

The thermal head 15 has 2560 elements R1 to R.
2560 are arranged in a row, and this element R1~
Image recording is performed one line at a time using R2560.

The shift register consisting of D flip-flops FFI to FF2560 transfers image data one line at a time and captures it by lock, and the latch circuit RTI to RT2560 sequentially latches the image data in shift registers FFI to FF2560 one line at a time by a latch signal. do.

Gates G1-G2560 are connected to latch circuits RTI to RT2 by strobe pulses from strobe circuit 17.
The image data from 560 is passed one line at a time in the order of odd-numbered dot data and even-numbered dot data, and is passed through transistors Tll to T12560. T21~
T22560 divides elements R1 to R2560 into two blocks, odd and even blocks, and connects them to gate 0.
Image recording is performed by sequentially energizing with image data from 1 to 02560. In this case, as shown in FIG.
Transferred to I~FF2560 and latch circuit RTl-RT
After being latched at 2560, the odd-numbered gate Gl,
When the strobe pulse from the strobe circuit 17 for G3...G 2559 becomes active, the odd-numbered gate Gl opens, and when the strobe pulse turns off, the odd-numbered gate Gl opens.

G3...G 2559 closes. Next, even-numbered gate G2. G4...G The strobe pulse from the strobe circuit 17 for G2560 becomes active and the even-numbered gate G2. G4...G
2560 opens, and when the strobe pulse turns off, the even numbered gate G2゜G4...G 2560 closes 0 Next, the second level H image data is transferred to the shift register FFI~F
Transferred to F2560 and latch circuit RTI~RT256
After being latched at 0, the odd numbered gates G1 . G3・
When the strobe pulse from the strobe circuit 17 to G2559 becomes active, the odd-numbered gates Gl, G3...G2559 open, and when the strobe pulse turns off, the odd-numbered gates Gl, G3.
...G 2559 closes. Next, even-numbered gate G2. G4...G The strobe pulse from the strobe circuit 17 for G2560 becomes active and the even-numbered gate G2. G4...G256
0 opens, and with the strobe pulse off, even-numbered gates G2. G4...G 2560 closes. Thereafter, similar operations are repeated from the third level image data to the 255th level image data.

FIG. 6 shows the configuration of the resistance value detection section, FIG. 8 shows the timing of its reference voltage setting mode, and FIG. 9 shows the normal thermal head drive timing.

When the power is turned on or the re-measurement switch is turned on, the microcomputer (CPU) (not shown) starts the thermal head 15.
Image data, latch signals, and strobe pulses are transferred to shift registers FF1 to FF2560 so that a plurality of elements R1 to R2560 are sequentially driven one by one.
, latch circuit RTI-RT2560, gate circuit 01~
Give to G 2560. Elements R1 to R2 560 are connected to a power supply via a resistor 46, and when only one element is driven, its driving voltage Vx is applied to a differential amplifier 5 consisting of an operational amplifier 47 and resistors 48 to 51.
At step 2, the voltage is compared with the reference voltage Vref, and the difference voltage is amplified. Here, the reference voltage Vref is the reference data from the CPU that is digital/analog (D/A
) D/A converted by the converter 53 and transferred to the transistor 54
and a resistor 55, and the amplification factor of the differential amplifier 52 is equal to the element R1.
~Differential amplifier 5 with the maximum and minimum resistance values of R2560
The output voltage Vout of No. 2 is set so as not to exceed the measurable range. The output voltage Vout of the differential amplifier 52 is converted from analog to digital by an analog/digital converter and input to the CPU. First of all, the CPU
As shown in FIG. 10, set so that only the first element R1 is driven by the input of image data, and vary the reference data so that the output voltage Vout of the differential amplifier 52 at that time becomes IV. The reference voltage V ref is varied by. And the CPU is a differential amplifier 5
When the output voltage Vout of 2 becomes IV, it is determined from the reference data at this time whether or not element R1 is disconnected and whether its resistance value is an abnormal resistance value. If the resistance value is abnormal, the display section displays an abnormality.

If element R1 is normal, the CPU determines whether the reference data is the minimum value, and sequentially performs the above operations for all elements R1 to R2560. however,
If the dot portions on both ends of the thermal head 15 are not driven as a print margin, the above operations can be performed sequentially for each element within the actual printing range.The CPU will then process the reference data obtained through the above operations. From the minimum value, as shown in FIG. 12, the time tl from the start of the element application pulse to the color development of the 1st level in multi-gradation recording, and the change in each time to the development of each color at the 2nd...64th level. The minutes and the remaining time t2 are calculated and set based on the relationship determined in advance through experiments.

Next, as shown in FIGS. 7 and 11, the CPU sets the reference data to the minimum value obtained in the above operation and drives the first element R1, and then the differential amplifier 52
Output voltage Vout (= (Vx −Vref)XA)
is converted into analog/digital data by an analog/digital converter, which is taken in as resistance value data of element R1 and stored in memory.

The CPU sequentially performs such operations on all elements.

FIG. 13 shows the configuration of the element number correction section 16.

The level frequency counter 57 counts the level frequency of the pulse number signal from the resistance correction unit 13 line by line, that is, how the pulse number signal is distributed at each level is counted line by line. Count the level frequency of each line. The element number calculation section 58 calculates the number of operating elements (the number of elements driven simultaneously) at each gradation level based on the level frequency counted by the level frequency counter 57, and the pulse width control section 59 calculates the number of operating elements (the number of elements driven simultaneously) at each gradation level. By accumulating the number of operating elements at each gradation level calculated by 58 and changing the energy application time to the thermal head 15 based on the number of operating elements at each gradation level, the recording density can be simultaneously operated. Control to be constant without being affected by the number of elements.

FIG. 14 shows the structure of the level frequency counter 11.

Random access memory (RAM) 60.61 has a capacity of 256 bits x 2 each as a frequency RAM6
2 and is used alternately for each level frequency measurement of the pulse number signal for one line, and is used alternately with the pulse number signal.

A select signal for selecting odd-numbered and even-numbered elements is input to the address line. And RAM60.6
1 is an odd count part E ven which counts the level frequency by the pulse number signal of odd numbered dots for one line as shown in FIG. 15 by inputting the select signal to the most significant bit of the address line; The even count portion Odd, in which the level frequency is counted based on the pulse number signal of the even numbered dots for one line, is switched and used each time the pulse number signal of each dot is input.

This is because when driving a plurality of elements in the thermal head 15, the plurality of elements are divided into two blocks, odd-numbered blocks and even-numbered blocks, and driven at different timings. Further, in the RAM 60.61, when the pulse number signal of each dot is input to the address line, 1 is added to the content of the address corresponding to the pulse number signal by the adding means 63 and saved at that address. R
It goes without saying that the contents of AM60.61 should be set to zero in advance. The RAM 60.61 has an address structure as shown in FIG. 15, in which the pulse number signal and the address correspond to each other, and the value obtained by counting the frequency of each gradation level becomes the content of each address. These two RAM6
0.61 toggles every time a 1″ line pulse number signal is input, and while one side is counting the level frequency for one line, the other side sends the count data to the next element number calculation unit 58 to an odd number. Transfer from the multi-gradation O level to the 254 level for the element, and then transfer from the multi-gradation O level to the 254 level for the even-numbered element.
Transfer to level.

FIG. 16 shows the configuration of the element number calculation section 58.

The gate 64 is opened by the first level enable signal, and the O level (first gradation level) data A0 from the level frequency counter 57 is subtracted from 1280, which is the maximum number of elements to which energy can be simultaneously applied, in the subtracter 65, and the result is The signal is transferred to the pulse width control section 59 of. Here, by subtracting O level data A0 from 1280, which is the maximum number of elements to which energy can be simultaneously applied, the number of odd-numbered elements to be simultaneously driven in the 1st level is determined. The latch circuit 66 operates when the first rubel enable signal is applied via the inverter 67 and the second rubel enable signal is turned off. The subtraction result of the subtracter 65 is latched by a latch circuit 66, and the gate 64 is closed when the first rubel enable signal is turned off. Lebel's data A1 from the level frequency counter 57 is subtracted from the value of the latch circuit 66 in a subtracter 65, and the number of odd-numbered elements simultaneously driven at the second level (second gradation level) is calculated by the next pulse. The signal is transferred to the width control section 59 and latched by the latch circuit 66 . Thereafter, the second level to the 254th level (second to second level)
The number of odd-numbered elements that are simultaneously driven at each gradation level (54 gradation levels) is determined and transferred to the pulse width control unit 59, and the number of odd-numbered elements that are simultaneously driven at each gradation level is similarly calculated for even-numbered elements. The number of pulse width controllers 59 is determined and transferred to the pulse width controller 59.

FIG. 17 shows the configuration of the pulse width control section 59.

The data transferred from the element number calculation section 58 is stored in the pulse width RAM 68. RAM6 for pulse width
8 consists of two RAMs 69.70, and toggles every time one extra inch of data is input. This R.A.
In the M69.70, when one side stores the data transferred from the element number calculating section 58, the other side stores the stored data in synchronization with the strobe signal, the data of the 1st level for odd-numbered elements, and the 1st level of data for even-numbered elements. data, second for odd elements
Lead for pulse width conversion in the following order: level data, second level data for even numbered elements, 255th level data for odd numbered elements, 255th level data for even numbered elements. Output to only memory (ROM) 71.

The pulse width conversion ROM 68 receives the input data as an address signal, reads out the data, and converts the input data into a timer value that eliminates recording density fluctuations due to the number of simultaneously driven elements. The timer 72 and the strobe generator 73 constitute the strobe circuit 17, and the timer 72 generates a timer from the pulse width conversion ROM 71 when odd-numbered elements and even-numbered elements are driven at each gradation level. The value is set and triggered by the timer start signal.

The strobe pulse generator 73 generates strobe pulses and applies them to the thermal head 15 after the timer start signal is input until the timer 72 times up.

FIG. 20 shows the configuration of the head driving section 14.

The head driving section 14 includes a line buffer 74 and a data converting section 75. The line buffer 74 uses a line memory 76 and counters 77 and 78.
The line memory 76 has 2 areas 76A each having 4 bytes.

76B and switched by a line synchronization signal. The counters 77 and 78 are a write counter 77 and a read counter 78, and have an initial value of 2559.
When the counters 77 and 78, which count down each time image data is written or read from the memory 76, reach O or later, no image data is written to the memory 76. The output value of counter 77.78 is Read/Write
It is switched by the mode signal, and the output values of the counters 77 and 78 are output alternately. As shown in FIG. 21, image data is written to the memory 76 at 2559°2558,
. . , O, the image data is written to the lower memory addresses one by one in the memory 76, and the image data is read out at 2559, 2495, . ..., 63,2
558.2494. ...62. . . , O, the image data is read from every 64th memory address in the memory 76. This is because each element driving section of the thermal head 15 has a 64-bit structure.

The data converter 75 includes first stage latch circuits Lll to L14.
0, PNM (Pulse Nu
mber Module) circuit PNMI ~ PNM40
, head memories old to M5 are used, and the first stage latch circuits Lll to L140 first read addresses 2559, 2495 . . . , 40 image data sequentially read from 63 are latched. After latching these 40 pieces of image data, the first stage latch circuit L
The contents of ll-L140 are simultaneously transferred to the second stage latch circuit L2.
1-Latched to L240.

■The data in the second stage latch circuits L21-L240 is compared with the comparison data O' from the comparison data generation counter 79 in the next stage PNM circuits PNMI-PNM40, and if it is larger than the comparison data, it is 1', and if it is less than the comparison data, it is 1'. If so, it is binarized to 0' and written to the primary stage head memory old to M5.

Next, the data in the second stage latch circuits L21 to L240 are compared with the comparison data l' from the comparison data generation counter 79 in the next stage PNM circuits PNMI to PNM40, and if it is larger than the comparison data, the comparison data is 1'; 0 if less than or equal to
' and written to the next stage head memory old to M5.

Next, the data in the second stage latch circuit L21-L240 is compared with the comparison data 2' from the comparison data generation counter 79 in the next stage PNM circuit PNMI-PNM40, and if it is larger than the comparison data, the data is 1'; If it is less than the comparison data, it is binarized to 0' and written to the primary head memory old to M5. The comparison data from the comparison data generation counter 79 has a threshold level that increases sequentially, and similarly, the data from the second stage latch circuits L21 to L240 is sent from the comparison data generation counter 79 to the next stage PNM circuits PNMI to PNM40. Comparison data of ``3'', ``4''
5',...,'255' are compared one after another and 2
The data is converted into a value, and each of the binary data is written into the head memory old to N5. Through this operation, the data in the second stage latch circuits L21 to L240 is converted to 256-gradation data and written into the head memories A1 to M5.

The upper 6 bits of the address of head memory old ~ M5 indicate the dot number, and the lower 8 bits indicate the level number (gradation level number). At ', the level number changes from '0' to '255' depending on the comparison data (gradation level) of the comparison data generation counter 79.

During the work in steps (1) to (2) above, the next 40 image data are stored in the line memory 76 at addresses 2558, 2494. ...,
62 and the latch circuit Lll-L1 of the first stage.
40 and is on standby.

When the above steps ■ to ■ are completed, the first stage latch circuit L
The contents of ll to L140 are simultaneously transferred to the second stage latch circuit L2.
1 to L240, and the dot number is set to 1', and by performing the operations ① to ② above, the data in the second stage latch circuits L21 to L240 is converted to 256 gradation data, and the data is stored in the old head memory. ~Written to M5.

Similarly, 40 pieces of image data are read out from the line memory 76 at a time, converted into 256-gradation data, and written into the head memories old to M5. In this case, the dot number is switched from 2' to 63' in response to reading of image data in increments of 40.

Next, the head latch signal LD is output from the head memories 1 to M5.
In synchronization with , data is read out with level number ``O'' and dot numbers ``0'' to ``63'' and sent to the thermal head 15 as image data DI, and then with level number ``1'' and dot number ``0''. ~ '63', the data is read and sent to the thermal head 15 as image data DI, and in the same way, each level number '2' ~ '25'
At step 5', data is read out as dot numbers 0' to 63' and sent to the thermal head 15 as image data DI.

Head memories old to M5 are each divided into two areas of 64 x 256 bytes like the line memory 76, and these two areas are switched by a line synchronization signal.

FIG. 22 shows the configuration of a resistance correction section in another embodiment of the present invention.

In this embodiment, the resistance correction section 13 in the above embodiment is constructed as shown in FIG. 22, and the parts other than the resistance correction section are constructed in the same manner as in the above embodiment.

The resistance correction section includes a lens 80 and an image pickup device 81 . It is composed of a CCD drive section 82, a correction section 83, and the like.

The rolled sublimation ink sheet 84 is pulled out from the supply roller 85 and sent to the thermal head 15 and platen drum 86.
It is wound up by a winding roller 87 through the gap between the two. In the normal print mode, the recording paper 88 is inserted between the ink sheet 84 and the platen drum 86, and the platen drum 86 is inserted with the recording paper 88 and the ink sheet 84 sandwiched between the thermal head 15 and the platen drum 86. By rotating, the recording paper 88 and the ink sheet 84 move between the thermal head 15 and the platen drum 86, while the elements R1,
R2, R3, ..., the recording paper 88 is removed from the ink sheet 84 due to the heat generated according to the image data of R2560.
The ink is transferred to and the image is printed.

Element R1, R2, R3,..., R256
In the resistance value measurement mode that measures the resistance value of 0, the recording paper 88
is inserted between the ink sheet 84 and the platen drum 86.

The printing operation on the recording paper 88 is performed almost in the same way as the printing operation in the normal print mode. In this case, the head driving unit 14 transfers uniform solid data supplied from the data generation source to the thermal head 15, and the recording density of the recording paper 88 is adjusted to elements R1, R2, R3, .
..., varies depending on the variation in the resistance value of R2560, etc. FIG. 23 shows the relationship between the number of pulses of the pulse number signal input to the head drive section 14 and the recorded green density OD of the recording paper 88 when the sublimation ink sheet 84 is used. The recording density OD of the recording paper 88 changes non-linearly in the low-density part and high-density part with respect to the number of pulses of the pulse number signal, and in the middle density part changes linearly with the number of pulses in the pulse number signal6. The number of pulses of the pulse number signal is Pa, PL,
If Ph, the recording density OD of the recording paper 88 is ODm, OD
I.

Changes to ODh. Therefore, in the resistance value measurement mode, the head drive unit 14 receives pulse numbers Pl from the data generation source for intermediate density portions, for example, ODI and ODh.

Each pulse number signal of ph is supplied for a plurality of lines.

Here, the intermediate density portion OD+s is ○Dm=ODmax/2 with respect to the maximum recording density ODmax of the recording paper 88, Ph=Pm+ΔP, and PL=P+++−ΔP.

The pulse numbers PL and Ph are set so that the recording density of any element is lower than ODa+ for a pulse number signal of pulse number P1 and higher than OD+a for a pulse number signal of pulse number ph, as shown in FIG. Number margin ΔP
It is set by taking The recording density of the recording paper 88 is the second
As shown in Figure 6, there should be two levels of concentration ○Dh and ODl depending on the number of pulses PL and Ph of the pulse number signal, but
As shown in FIG. 25, each element R1, R2, R3,
..., Variation in the resistance value of R2560, each element R1, R2, R3, ..., variation in pressure between R2560 and recording paper 88, each element R1, R
2, R3,..., Due to variations in the amount of heat generated due to variations in the applied voltage of R2560, variations in wiring, etc., the recording density becomes ○Dh for the pulse number signal of the pulse number ph.
,,ODh2. The number of pulses Pi changes as ODh,...
For the pulse number signal of ODI, ○D1□, ○DI,
...and fluctuate. The recording density of this recording paper 88 is 0Dh1
．． ODh,, 0Dh3..., ○D1 engineering, 0DI2,0
For DI3..., the number of pulses ph and the recording density are linear, so...(1) is obtained. However, i indicates the number of the element.

The recording paper 88 is connected to the thermal head 15 and the platen drum 86
After passing between the recording paper 88 and the ink sheet 84, the recording paper 88 is separated and illuminated by a light source 89, and the reflected light is photoelectrically converted by a CCD 81 via a lens 80, and the recording density of the recording paper 88 is measured. The CCD 81 is driven by a CCD driving section 82 , and the output signal of the CCD 81 is sent to the correction section 83 via the CCDM moving section 82 . In this case, the CCD drive unit 82 uses the CCD 8 to drive the recording paper 88 before measuring the recording density.
The output signal of CCD 81 is stored in a memory as shading correction data, and when recording density is measured, the output signal of CCD 81 is subjected to shading correction using the shading correction data, A/D converted, and then sent to correction section 83.

As shown in FIG. 27, the correction unit 83 has a one-line OD memory 89. Arithmetic unit 90. It is composed of a line data memory 91 and a data converter 92. Recording density 0Dh1°0Dh2 according to the number of pulses ph from the CCD drive unit 82
．． The density signals for ODh, .
Recording density ODI according to the number of pulses P1 from the drive section 82
□, ODI□OD1. The above formula (1) is calculated for each element from the density signal for one line for . It is written into the line data memory 91 as . In normal print mode, information is read from the line data memory 91 based on the number (No) information of the element that records one pixel, and the data converter 92 converts the image data from the line data memory 91 to the image data from the resistance correction unit 13. By subtracting the density data, each element R1,
R2, R3,..., variation in resistance value of R2560, each element R1, R2, R3,...
There are no fluctuations in recording density due to variations in the pressure between R2560 and the recording paper 88, variations in the voltage applied to each element R1, R2, R3, etc., R2560, variations in heat generation due to variations in wiring, etc., and recording is possible. The image is corrected so that the density is uniform and output to the head driving section 14.

〔Effect of the invention〕

As described above, according to the present invention, in a head having a plurality of elements arranged in a line, the plurality of elements are heated in accordance with multivalued image data, and pixels are recorded one line at a time. In the apparatus, a thermal influence calculation means for calculating the influence on the recorded pixel density due to the thermal influence of surrounding elements on the element that records pixels among the plurality of elements and the heat accumulation of the element that records nine pixels. a storage means for storing data of the measured resistance values of each of the plurality of elements or recording density correction data of each recording position corresponding to each position of the plurality of elements; simultaneously driven element number calculation means for calculating the number of simultaneously driven elements in the elements;

The relationship between the image data and the pixel density recorded by the element is sequentially computed by the thermal influence computing means;
Since it is equipped with a correction means that corrects the data stored in the storage means and the calculation results of the number calculation means of simultaneously driven elements, it is possible to perform multi-gradation correction with a simple configuration so that recording density fluctuations due to heat accumulation in each element, etc. do not occur. Image recording can be performed. Moreover, the relationship between the image data and the recorded pixel density by the element is corrected based on the calculation results of the thermal influence calculation means, and correction is performed using the data stored in the storage means.

Since the corrections are performed in the order of the calculation results of the simultaneously driven element number calculation means, these corrections can be performed efficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the adjacent history correction section in the same embodiment, and FIG. 3 is a block diagram showing the configuration of the heat storage calculation section in the adjacent history correction section. FIG. 4 is a block diagram showing the configuration of the rising/falling correction section in the above embodiment, FIG. 5 is a block diagram showing a part of the above embodiment, and FIG. 6 is a resistance value detection in the above embodiment. 7 to 9 are timing charts for explaining the operation of the resistance value detection section, and FIGS. 10 and 11 show the processing flow of the CPU in the resistance value detection section. Flowchart showing,
FIG. 12 is a diagram for explaining the operation of the resistance value detection section,
FIG. 13 is a block diagram showing the configuration of the element number correction section in the above embodiment, FIG. 14 is a block diagram showing the configuration of the level frequency counter in the element number correction section,
FIG. 15 is a block diagram showing the frequency RAM in the same level frequency counter, FIG. 16 is a block diagram showing the configuration of the element number calculation section in the element number correction section, and FIG. 17 is pulse width conversion in the element number correction section. FIG. 18 is a timing chart of the above embodiment, FIG. 19 is a block diagram showing the circuit structure of the thermal head in the above embodiment, and FIG. 20 is a structure of the head drive section in the above embodiment. FIG. 21 is a timing chart of the head driving section, and FIGS. 22(a) and 22(b) are a schematic diagram and a front view showing a part of another embodiment of the present invention. FIG. 23 is a characteristic curve diagram showing the pulse number vs. recording density characteristic of the pulse number signal in the same embodiment, FIGS. 24 to 26 are diagrams for explaining the same embodiment, and FIG. FIG. 3 is a block diagram showing the configuration of a correction section. FIG. 28 is a diagram for explaining the same embodiment, and FIG. 29 is a diagram for explaining a conventional recording apparatus. DESCRIPTION OF SYMBOLS 11... Adjacent history correction part, 12... Rising/falling correction part, 13... Resistance correction part, 16... Element number correction part. Process 7 ■ θV−−−−−−− −1−−−−−−Yafu start θ−−−−−−−−−−−−−−−−−−−−De°−Evening <D −−Bee)−−−−+I'm lazy
”-=7 clock Ju
Hee--Jlt- 䑑lθ 所16 ■ /7P)lq ■ B22Fig.

Claims (1)

[Claims] In a recording device that records pixels line by line by heating the plurality of elements in a head having a plurality of elements arranged in a line in accordance with multivalued image data, the plurality of elements a thermal influence calculation means for calculating the influence on the recorded pixel density due to the thermal influence of surrounding elements on the element that records the pixels and the heat accumulation of the element that records the pixels; storage means for storing resistance value data measured by the plurality of elements or recording density correction data for each recording position corresponding to the individual positions of the plurality of elements; and elements in the plurality of elements that are driven simultaneously based on the image data. a simultaneously driven element number calculation means for calculating the number of simultaneously driven elements; and a calculation result of the thermal influence calculation means, the data stored in the storage means, and the simultaneously driven elements, which sequentially calculate the relationship between the image data and the pixel density recorded by the elements. A recording device comprising: a correction means for correcting based on the calculation result of the numerical calculation means.