JP4854254B2 - Thermal transfer recording apparatus and control method thereof - Google Patents

Description

  The present invention relates to a thermal transfer recording apparatus that records color images in a frame sequential manner and a control method thereof.

  Thermal printers have a thermal recording system in which the thermal recording paper is heated directly by the thermal head and the color is directly developed, and thermal transfer is performed by heating the ink ribbon superimposed on the recording paper with the thermal head and transferring the ink to the recording paper. There is a recording method. The thermal transfer recording method is roughly classified into a melt type thermal transfer type in which the ink is melted and transferred by the heat of the head and a sublimation type thermal transfer type in which the ink is vaporized and transferred. In the thermal head, a large number of heating elements (resistors) are formed in a line on a ceramic substrate, and the amount of heat generated can be controlled by the power supplied to these elements. The sublimation thermal transfer type can control the amount of ink transferred by controlling the amount of heat applied to the ink by controlling the amount of heat generation, which is superior in terms of gradation expression compared to the melt type transfer type. ing.

  As described above, in the thermal printer, since the image is stored by the heat generated by driving the heating element, a high-quality image can be obtained simply by driving each heating element of the thermal head according to the input image data. I can't.

  This is because the image quality deteriorates due to heat storage of the head itself. For example, a trailing phenomenon is known in which a portion that is not originally required to be printed is printed. In addition, at the start and end of image printing, even if the heating element is driven with the same image data, the recording density at the end of printing is higher than the recording density at the start, resulting in lower image quality. There are things to do. Such a phenomenon is caused by storing a part of the heat energy generated from each heating element in the glaze layer of the thermal head. The stored thermal energy depends on the past heat generation state of the heating element.

In order to avoid such a phenomenon, a method of controlling the heat generation driving of the pixel of interest according to the heat generation state of the pixel existing around the pixel of interest is known. For this purpose, for example, a filtering operation is performed on 3 × 3 or 7 × 7 pixel data to correct the pixel data of the pixel of interest. Patent Documents 1 and 2 describe adding image data up to the (N−1) th line by each heating element when recording an image of the Nth line. According to Patent Documents 1 and 2, a method is proposed in which the heat storage correction amount of each element in the line is obtained and corrected based on the value obtained by addition.
JP 59-098878 JP 09-052382 A

  In such a conventional method, it is possible to correct the influence of heat storage in each plane to be printed. However, in a color thermal transfer printer that performs surface sequential printing using ink ribbons to which a plurality of colors of ink are applied, heat storage due to previous printing is not sufficiently considered when printing on each surface is started. In other words, heat storage in the preceding color printing is not taken into consideration when printing is performed in a frame sequential manner using ink ribbons that can be printed in yellow, magenta, and cyan colors. For this reason, for example, when color printing is performed in the order of the Y plane, M plane, and C plane, the heat accumulated in the thermal head during printing on the Y plane may affect the subsequent printing on the M plane. In such a case, there is a problem that an area in which a magenta image is printed is generated although magenta image data does not originally exist. Such a problem becomes more prominent when the time from the end of printing on the Y side to the start of printing on the M side (and M side to C side) is shortened by increasing the printing speed to shorten the printing time. It becomes.

  An object of the present invention is to solve the problems of the conventional example.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal transfer recording apparatus and a control method therefor that prevent image degradation due to heat accumulation in image recording in a frame sequential manner. In addition, the feature of the present invention is that, when recording images in the surface sequential manner, the heat storage control at the time of image recording on the surface to be recorded is executed in consideration of the effect of heat storage by image recording on the immediately preceding surface. .

In order to achieve the above object, a thermal transfer recording apparatus according to an aspect of the present invention has the following configuration. That is,
A thermal transfer recording apparatus that records color images in a surface sequential manner using a thermal head ,
A heat storage amount coefficient calculating means for calculating a heat storage amount coefficient for each line;
A heat storage compensation amount calculating means that to calculate the accumulated-heat correction amount based on the quantity of thermal storage coefficient calculated in the previous SL stored heat quantity coefficient calculating means,
And a correcting means for correcting the image data of the record object in response to the accumulated-heat correction amount calculated by the previous SL accumulated-heat correction amount calculating means,
The heat storage amount coefficient calculating means includes:
The heat storage coefficient Hy (i) for the second and subsequent lines on the same surface is set to y as the number of lines, i as the i-th pixel data in one line, and Ly (i) as the i-th pixel data in the y-line, When K is a coefficient determined by the thermal storage characteristics of the thermal head,
Hy (i) = Ly (i) + K × Hy-1 (i) (y ≧ 2)
Calculated by
The heat storage coefficient H (i) for the first line on the first surface is set to H (i) = 0,
Heat storage coefficient Hy (i) of the first line after the second surface is Hy-1 (i) as the heat storage coefficient of the last line of the previous surface, and R is a heat dissipation coefficient (0 ≦ R ≦ 1.0) When
Hy (i) = Ly (i) + K × Hy−1 (i) × R (y = 1)
It is characterized by calculating by .

In order to achieve the above object, a method for controlling a thermal transfer recording apparatus according to an aspect of the present invention includes the following steps. That is,
A method for controlling a thermal transfer recording apparatus that records color images in a surface sequence using a thermal head ,
A heat storage amount coefficient calculating step for calculating a heat storage amount coefficient for each line;
A heat storage correction amount calculating step that to calculate the accumulated-heat correction amount based on the quantity of thermal storage coefficient calculated in the previous SL stored heat quantity coefficient calculation step,
And a correction step of correcting the image data of the record object in response to the accumulated-heat correction amount calculated in the previous SL accumulated-heat correction amount calculating step,
The heat storage coefficient calculation step includes
The heat storage coefficient Hy (i) for the second and subsequent lines on the same surface is set to y as the number of lines, i as the i-th pixel data in one line, and Ly (i) as the i-th pixel data in the y-line, When K is a coefficient determined by the thermal storage characteristics of the thermal head,
Hy (i) = Ly (i) + K × Hy-1 (i) (y ≧ 2)
Calculated by
The heat storage coefficient H (i) for the first line on the first surface is set to H (i) = 0,
Heat storage coefficient Hy (i) of the first line after the second surface is Hy-1 (i) as the heat storage coefficient of the last line of the previous surface, and R is a heat dissipation coefficient (0 ≦ R ≦ 1.0) When
Hy (i) = Ly (i) + K × Hy−1 (i) × R (y = 1)
It is characterized by calculating by .

According to the present invention, there is an effect that it is possible to prevent image deterioration due to heat accumulation in frame sequential image recording.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention according to the claims, and all combinations of features described in the present embodiments are essential to the solution means of the present invention. Not exclusively.

  FIG. 1 is a block diagram illustrating a schematic configuration of a thermal transfer printer according to an embodiment of the present invention. In this embodiment, the printer thermal head uses a fixed line type thermal head as an example. The printer of this embodiment prints a color image in the order of the Y side, M side, and C side using yellow, magenta, and cyan ink sheets while conveying the recording paper (transfer sheet). And In this embodiment, a sublimation type thermal transfer printer will be described as an example.

  This printer performs printing based on image data transmitted from the host computer 103. The control unit 100 controls the operation of the entire printer under the control of the CPU 120. The receiving unit 101 receives image data transmitted from the host computer 103. The receiving unit 101 has an interface such as USB, IEEE1394, Centronics, or wireless. The image processing unit 102 has the configuration shown in FIGS. 2 and 3, converts the image data received by the receiving unit 101 to create thermal head drive data (print data), and outputs the thermal head drive data to the head driver 104. . The image processing unit 102 may be realized by hardware or may be realized by a program executed by the CPU 120.

  The thermal head 105 is a fixed line-type thermal head, and has a heating element array having a length corresponding to the recordable width of a printable recording sheet (transfer sheet). The head driver 104 heats and drives each heating element of the thermal head 105 according to the print data supplied from the control unit 100. The LF motor 107 is a motor that drives and conveys the transfer sheet, and is rotationally driven via a motor driver 106 by a drive signal from the control unit 100. The sheet conveying motor 109 is a motor for conveying an ink sheet in accordance with the above-described surface sequential printing, and is rotationally driven via a motor driver 108 by a drive signal from the control unit 100. Here, the ink surface of the ink sheet having a size corresponding to one page is repeatedly formed in the order of YMC, and when the printing on the Y surface is completed, the ink sheet on the next M surface is positioned at the printing position. Be transported. Similarly, the ink sheets are positioned in the order of YMC, and the ink melted by heating by the thermal head 105 is transferred to the transfer sheet to record a color image.

  Next, the control unit 100 will be described. The CPU 120 controls the operation of the entire printer according to a control program stored in the ROM 121. The RAM 122 stores image data received by the receiving unit 101 and print data created by the image processing unit 102, and is also used as a work area for temporarily storing various data during control processing of the CPU 120.

  FIG. 2 is a block diagram showing a functional configuration of the image processing unit 102 of the thermal transfer printer according to the present embodiment.

  In FIG. 2, a color conversion circuit 200 converts an RGB signal received and input by the receiving unit 101 into a CMY signal that is a color space for printing. Here, RGB 8-bit signals are received and converted into 8-bit CMY signals by matrix operation as shown in Equation (1).

| Cm | | M11 M21 M31 | | 255-R |
| Mm | = | M12 M22 M23 | × | 255-G |
| Ym | | M13 M23 M33 | | 255-B |
Here, M11 to M are 33, conversion coefficients.

  The CMY signal converted by the equation (1) is converted by the gradation conversion circuit 201 into the number of pulses for driving the heat generating elements of the thermal head 105 according to the values of the CMY signal. The conversion here is executed using a lookup table prepared in advance for each of C, M, and Y. In the present embodiment, the input CMY 8-bit data is converted into 10-bit data.

Ct = LookUPTableC [Cm] ... Formula (2)
Mt = LookUPTableM [Mm] ... Formula (3)
Yt = LookUPTableY [Ym] ... Formula (4)
The 10-bit data of Ct, Mt, and Yt converted using the look-up table is stored in the memory area 204 of the RAM 122. Thus, the RAM 122 stores print data for one page of each CMY.

  Next, the operation in the heat storage correction circuit 202 will be described.

  First, the Y plane data to be printed is sent to the heat storage correction circuit 202.

  The heat storage amount coefficient calculation circuit 210 has a main scanning direction X when the arrangement direction of the heating elements of the thermal head 105 is the main scanning direction X and the direction in which the transfer sheet moves relative to the thermal head 105 is the sub scanning direction Y. A heat storage coefficient is calculated for each line of data.

  The pulse signal corrected by the heat storage correction circuit 202 is output to the head driver 104 to drive the thermal head 105.

  FIG. 3 is a block diagram showing a configuration of the heat storage amount coefficient calculation circuit 210 according to the present embodiment.

  When the data L for one line on the printing surface is sent to the heat storage amount coefficient calculation circuit 210, the delay data one line before stored in the one line delay 302 (heat storage amount coefficient one line before) is read out. . The read delay data is multiplied by the coefficient K in the gain calculation circuit 301 and output to the adder 305. The adder 305 adds the input current line data L and the value obtained by multiplying the heat storage amount coefficient H of the previous line by the coefficient K, and outputs the result as a heat storage amount coefficient H.

  Here, K is determined by the heat storage characteristic of the thermal head 105 and is a value from 0 to 1.0. The one-line delay 302 is composed of a memory for one line of main scanning in the RAM 122 described above. When the calculation of the heat storage coefficient H is expressed by an equation, the following equation (5) is obtained. However, here, the i-th pixel data of the current one-line data Ly is expressed as Ly (i). In the present embodiment, since the number of pixels (the number of heating elements) of the thermal head 105 is “1280”, i takes a value of 1 to 1280 (i = 1 to 1280). Further, y is the printing position in the sub-scanning direction within the printing surface of each color, that is, the number of lines, and y = 1 to 2000 when one page is composed of, for example, 2000 lines.

  Therefore, the heat storage coefficient H of each heating element in the y line is expressed by the following equation.

Hy (i) = Ly (i) + K × Hy-1 (i) (y ≧ 2 ) (5)
However, in the first line when printing on the Y side, H (i) (i = 1 to 1280) is all “0”.

In the second line when printing on the Y side,
H2 (i) = L2 (i ) + K × H 1 (i) (y = 2) ... formula (5 ')
It becomes.

  Thus, the heat storage amount coefficient H for each heating element is obtained for each line.

  The initial value setting circuit 303 sets the heat storage amount coefficient obtained for the last line of the previous surface in the 1-line delay 302 when the first line of each color surface is processed. However, as described above, “0” is set in the first line of the Y plane where printing is performed first.

  As described above, the printer according to the present embodiment prints the Y plane, the M plane, and the C plane in the order of frames. At the time of processing the first line of the first Y plane, the initial heat storage amount coefficient determination circuit 304 generates an initial value “0” signal and sends it to the initial value setting circuit 303. Therefore, the delay data H (i) output from the one-line delay 302 is all “0” on the first line of the first Y plane. In the second line, the delay data H1 (i) output from the first line delay 302 is a heat storage amount coefficient H based on the data in the first line, and the heat storage amount of the second line is calculated by the above equation (5 ′). A coefficient H2 (i) is obtained.

  Thereafter, printing of the Y surface is sequentially executed in the same manner, and when the (final line) of the Y surface is printed, the heat storage amount coefficient Hy (i) for the final line stored in the one-line delay 302 is the initial heat storage amount. It is sent to the coefficient determination circuit 304.

  At the time of printing the first line on the next surface (here, M surface), the initial heat storage amount coefficient determination circuit 304 multiplies the heat storage amount coefficient Hy (i) for the last line on the Y surface by the heat dissipation coefficient R, and this is initialized. It is determined as the heat storage coefficient IHp (i). This is expressed by equation (6).

IHp (i) = Hy (i) × R (6)
The heat dissipation coefficient R here is set according to each time from the end of printing on the Y side to the start of printing on the M side, and from the end of printing on the M side to the start of printing on the C side. The heat dissipation coefficient R is a coefficient set by the printer, and is set to any value from “0” to “1.0”.

  In this way, the initial heat storage amount coefficient IHp (i) determined by the initial heat storage amount coefficient determination circuit 304 after the end of printing of the final line on the Y plane is sent to the initial value setting circuit 303 and set. Then, at the time of printing the first line on the next M plane, the initial value set in the initial value setting circuit 303 is set in the 1-line delay 302, and the printing process for the first line on the M plane is performed.

  The heat storage amount coefficient H of the first line on the M plane is expressed by the following equation (7).

H1 (i) = L1 (i) + K × IHp (i) (y = 1) (7)
And after the 2nd line, the heat storage coefficient H is calculated | required by the following formula | equation (8).

Hy (i) = Ly (i) + K × Hy-1 (i) (y ≧ 2) (8)
Thereafter, the same processing is performed when the C side is printed.

  When the heat storage amount coefficient Hy (i) is thus obtained for each line, the heat storage correction amount Sy (i) is obtained from the heat storage amount coefficient Hy (i) by calculation in the heat storage correction amount calculation circuit 211. The calculation here is obtained by dividing by a constant D. This is expressed by equation (9).

Sy (i) = − 1 × Hy (i) / D (9)
The heat storage correction amount Sy (i) thus obtained and the number of pulses output from the gradation conversion circuit 201 are added by the adder 212 to obtain a correction signal. This correction signal is output to the head driver 104, and the thermal head 105 is driven to generate heat to perform printing.

  In this embodiment, the gain calculation circuit 301 performs multiplication by a constant K. However, since the heat storage state in the thermal head 105 changes depending on the temperature inside the printer, the gain coefficient K may be obtained by the following equation (10). In this equation (10), the internal temperature of the printer may be obtained as a function of temp and multiplied.

K = FKtemp (temp) ... Formula (10)
Similarly, in the initial heat storage coefficient determination circuit 304, multiplication is performed by a constant R. However, it may be obtained by a function of the printer internal temperature and multiplied.

R = FRtemp (temp) ... Formula (11)
A case where the above-described processing is performed by a program executed by the CPU 120 of the control unit 100 will be described.

  4 and 5 are flowcharts for explaining a printing process for one color image page in the printer according to the present embodiment. Note that a program for executing this processing is stored in the ROM 121 and executed under the control of the CPU 120.

  First, when RGB image data is input from the host computer 103 in step S1, the image data is converted into CMY data according to equation (1) in step S2. Then, it is converted into a pulse signal (Ct, Mt, Yt) for driving the thermal head 105 according to the aforementioned equations (2) to (4).

  Next, in step S3, the rotation of the LF motor 107 is started and conveyance of the transfer sheet (recording sheet) is started. In step S4, the ink sheet conveying motor 109 is driven to rotate, and the Y ink sheet to be printed first is positioned corresponding to the printing surface.

  Next, in step S5, for the first line of Y data to be printed first, the heat storage correction amount S is obtained by setting the heat storage amount coefficient corresponding to each heating element of the thermal head 105 to “0”. Then, the addition result of the heat storage correction amount S and the first line Y data is output to the head driver 104, and the first line Y data is printed. Next, the process proceeds to step S6, and in the second line of the Y data and the subsequent lines, the heat storage correction amount S is obtained based on the heat storage amount coefficient corresponding to each heating element in the previous line. In step S7, the addition result of the heat storage correction amount S obtained in step S6 and the Y data of the current line is output to the head driver 104, and the Y data of the current line is printed. In step S8, it is checked whether printing based on Y data has been completed. If not, the process returns to step S6 to execute the above-described printing process for each line. When printing based on the Y data is thus completed, the process proceeds to step S9.

  In step S9, the LF motor 107 is reversely rotated to return the transfer sheet by the recording length (one page) for printing the next color (M). In step S10, the sheet conveying motor 109 is driven to rotate forward so that the M (magenta) ink sheet positioned after Y is associated with the printing position. Next, in step S11, in the first line of the M data, the heat storage correction amount S is obtained based on the heat storage amount coefficient corresponding to each heat generating element in the final line on the Y plane, and this and the M data in the first line The addition result is output to the head driver 104, and the M data of the first line is printed. Next, in step S12, in the same manner as in steps S6 and S7 described above, in the second line of the M data and subsequent lines, the heat storage correction amount S is based on the heat storage coefficient corresponding to each heating element in the previous line. Ask for. Then, the addition result of the obtained heat storage correction amount S and the current line M data is output to the head driver 104, and the current line M data is printed. Next, in step S13, it is checked whether or not printing based on the M data has been completed. If not, the process returns to step S12 to execute the printing process for each line described above. When the printing based on the M data is thus completed, the process proceeds to step S14 (FIG. 5).

  In step S14, the LF motor 107 is reversely rotated to return the transfer sheet by the recording length (one page) for the next color (C) printing. In step S15, the sheet conveying motor 109 is driven forward so that the C (cyan) ink sheet positioned next to M is associated with the printing position. Next, in step S16, in the first line of the C data, the heat storage correction amount S is obtained based on the heat storage amount coefficient corresponding to each heating element in the final line of the M plane, and this and the C data in the first line The addition result is output to the head driver 104, and the C data of the first line is printed. Next, in step S17, in the same manner as in steps S6 and S7 described above, in the second line of the C data and subsequent lines, the heat storage correction amount S is based on the heat storage coefficient corresponding to each heating element in the previous line. Ask for. Then, the addition result of the obtained heat storage correction amount S and the current line C data is output to the head driver 104, and the current line C data is printed. Next, in step S18, it is checked whether printing based on the C data has been completed. If not, the process returns to step S17 to execute the above-described printing process for each line. When printing based on the C data is thus completed, the process proceeds to step S19.

  In step S19, the LF motor 107 is driven to rotate, and the color-printed transfer sheet on which the three colors are overprinted is discharged out of the printer. In step S20, the sheet conveying motor 109 is rotationally driven to position the ink sheet so that the Y ink sheet used in the next printing comes to the printing position.

  As described above, according to the present embodiment, in the thermal head printer that performs surface sequential printing, the effect of heat storage during Y-side printing is reflected on the M-side, and the effect of heat storage during M-side printing is reflected on the C-side. This enables a good printout operation that eliminates the effects of heat storage.

  In the present embodiment, the case of printing with three YMC colors has been described. However, the present invention is not limited to this, and black, light magenta, and cyan ink sheets may be added. . Even in such a case, the point that heat storage in the previous color plane is taken into consideration at the start of printing of each color plane is performed in the same manner as in the previous embodiment.

  Further, in the present embodiment, a configuration in which an LF motor for transporting a transfer sheet (recording sheet) and a sheet transport motor for transporting an ink sheet are provided separately is described as an example. However, the present invention is not limited to this, and these may be constituted by a single motor and a clutch for switching and transmitting the rotation of the motor. Thereby, the manufacturing cost of an apparatus can be held down.

  Further, by separately providing the LF motor and the sheet conveying motor, the transfer sheet and the ink sheet can be simultaneously conveyed in parallel in the above-described steps S9, S10, S14, S15, and steps S19, S20. it can. This has the effect of increasing the printing speed.

  Further, the present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), or an apparatus composed of a single device (for example, a copier, a facsimile apparatus, etc.) It may be applied.

  Another object of the present invention is to mount a storage medium recording software program codes for realizing the functions of the above-described embodiments in a system or apparatus, and read and execute the installed program codes from the storage medium. Is also achieved. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, the functions of the above-described embodiment are realized by executing the program code read by the computer. In addition, the operating system (OS) running on the computer performs part or all of the actual processing based on the instruction of the program code, and the functions of the above-described embodiments are realized by the processing. It is.

  Furthermore, the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, and the CPU of the main body executes part or all of the processing. Thus, the functions of this embodiment may be realized.

  The storage medium for supplying the program includes, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, and nonvolatile memory. There are cards. Furthermore, ROM and DVD (DVD-ROM, DVD-R) are also included.

  Alternatively, the browser of the client computer may be used to connect to a homepage on the Internet, and the computer program itself of the present invention or a compressed file including an automatic installation function may be downloaded from the homepage to a storage medium. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the claims of the present invention.

  Although the present invention has been specifically described above based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

1 is a block diagram illustrating a schematic configuration of a thermal transfer printer according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a functional configuration of an image processing unit of the thermal transfer printer according to the present embodiment. It is a block diagram which shows the structure of the thermal storage amount coefficient calculation circuit which concerns on this Embodiment. , 6 is a flowchart for explaining a printing process for one page of a color image in the printer according to the present embodiment.

Claims (3)

A thermal transfer recording apparatus that records color images in a surface sequential manner using a thermal head ,
A heat storage amount coefficient calculating means for calculating a heat storage amount coefficient for each line;
A heat storage compensation amount calculating means that to calculate the accumulated-heat correction amount based on the quantity of thermal storage coefficient calculated in the previous SL stored heat quantity coefficient calculating means,
And a correcting means for correcting the image data of the record object depending on the heat storage correction amount calculated by the previous SL accumulated-heat correction amount calculating means,
The heat storage amount coefficient calculating means includes:
The heat storage coefficient Hy (i) for the second and subsequent lines on the same surface is set to y as the number of lines, i as the i-th pixel data in one line, and Ly (i) as the i-th pixel data in the y-line, When K is a coefficient determined by the thermal storage characteristics of the thermal head,
Hy (i) = Ly (i) + K × Hy-1 (i) (y ≧ 2)
Calculated by
The heat storage coefficient H (i) for the first line on the first surface is set to H (i) = 0,
Heat storage coefficient Hy (i) of the first line after the second surface is Hy-1 (i) as the heat storage coefficient of the last line of the previous surface, and R is a heat dissipation coefficient (0 ≦ R ≦ 1.0) When
Hy (i) = Ly (i) + K × Hy−1 (i) × R (y = 1)
The thermal transfer recording apparatus characterized by the above-mentioned calculation . 2. The thermal transfer recording apparatus according to claim 1, further comprising a gradation conversion circuit for converting into a number of pulses for driving each heating element of the thermal head in accordance with each value of the CMY signal of the image data . A method for controlling a thermal transfer recording apparatus that records color images in a surface sequence using a thermal head ,
A heat storage amount coefficient calculating step for calculating a heat storage amount coefficient for each line;
A heat storage correction amount calculating step that to calculate the accumulated-heat correction amount based on the quantity of thermal storage coefficient calculated in the previous SL stored heat quantity coefficient calculation step,
And a correction step of correcting the image data of the record object in response to the accumulated-heat correction amount calculated in the previous SL accumulated-heat correction amount calculating step,
The heat storage coefficient calculation step includes
The heat storage coefficient Hy (i) for the second and subsequent lines on the same surface is set to y as the number of lines, i as the i-th pixel data in one line, and Ly (i) as the i-th pixel data in the y-line, When K is a coefficient determined by the thermal storage characteristics of the thermal head,
Hy (i) = Ly (i) + K × Hy-1 (i) (y ≧ 2)
Calculated by
The heat storage coefficient H (i) for the first line on the first surface is set to H (i) = 0,
Heat storage coefficient Hy (i) of the first line after the second surface is Hy-1 (i) as the heat storage coefficient of the last line of the previous surface, and R is a heat dissipation coefficient (0 ≦ R ≦ 1.0) When
Hy (i) = Ly (i) + K × Hy−1 (i) × R (y = 1)
A method of controlling a thermal transfer recording apparatus, characterized in that

Images