JP2000135853A - Apparatus and method for rotatably printing and method for converting image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a disc printing medium without distorting an image expressed in an orthogonal coordinate type by providing an image converting means for converting orthogonal coordinate type image data into rotational coordinate type image date. SOLUTION: In order to take out rotational coordinate type image data necessary to print a disc printing medium from image region Q, a circular image region U is disposed. The region U has a radius corresponding to the number of pixels from a rotating center O (Xo, Yo) to a first sub-operation line of an outermost periphery. Then, an orthogonal coordinates (Y, Y) of the pixel including a rotational coordinate point (r, c) is obtained from a numeric value L expressing a radius from the center O to the pixel P by number of pixels and an angle counterclockwise around the pixel P from an X-axis direction. Image data of the pixel specified by the coordinates (X, Y) is taken out as image data Pixel Data (c, r). This operation is conducted as to all or part of the radius coordinate c and the angle coordinate r, and converted into rotational coordinate type image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a CD-R (Compac
The present invention relates to a rotary printing apparatus and a method for printing on a disk printing medium such as a disk-recordable medium. Further, the present invention relates to an image conversion method for converting rectangular coordinate type image data into rotational coordinate type image data.

[0002]

2. Description of the Related Art CD-R (Compact Disk-Recordable)
Is a read-only CD and CD-ROM (Read Only)
Memory) is a write-once optical disc on which data can be recorded only once. CD-R with recorded data
Can be played back by the playback device, just like CDs and CD-ROMs. Due to its low cost, easy handling, and large storage capacity, it is often used to publish about 100 small-scale software.

One side of a CD and a CD-ROM is used as a recording side for recording and reading data, and the other side is generally used as a printing side for printing a title or the like. In the case of CDs and CD-ROMs, printing is generally performed by a large printing device in order to publish a large volume of the same design, whereas in the case of CD-Rs, it is used for small volume publishing and personal use. There has been a demand for a small and inexpensive printer that can easily create and change print contents for each sheet.

[0004]

Such a printer is disclosed in JP-A-5-238005 and JP-A-6-31906.
Some are described in. These information recording devices record information on a recording surface of an optical disk from a pickup, and perform ink-jet printing on a printing surface. Printing on the optical disc is performed while moving the inkjet nozzle in the radial direction of the optical disc and rotating the optical disc.

[0005] Such an information recording apparatus is provided with an ink cartridge, a mechanism for guiding ink to an ink jet head, and a pickup for information recording for ink jet printing, and the apparatus is large and complicated. . Further, since the ink jet head and the pickup are provided in the same device, ink scattered from the ink jet head may adhere to the pickup and prevent recording of information. Further, maintenance work such as replacement of the ink cartridge and cleaning around the ink jet head is troublesome.

Further, the radial direction of the optical disk is the main scanning direction, and the circumferential direction of the optical disk is the sub-scanning direction.
When the image data of the row-by-N-column rectangular coordinate type is used as it is as the print data, the print area is curved in a fan shape along the circumference of the optical disk, the inner side shrinks in the circumferential direction, and the outer side is the circumferential direction. The image becomes distorted and stretched.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotary printing apparatus and method capable of forming an image represented in a rectangular coordinate format on a disk printing medium without distortion.

Another object of the present invention is to provide an image conversion method capable of faithfully converting an image in a rectangular coordinate format into an image in a rotational coordinate format.

[0009]

SUMMARY OF THE INVENTION The present invention provides a print head for printing in the main scanning direction along the radial direction of a disk print medium, and the disk in a sub-scan direction along the circumferential direction of the disk print medium. A medium rotating means for rotating the printing medium, and a rotating coordinate type constituted by a plurality of pixels arranged in a main scanning direction and a sub-scanning direction of the disk printing medium in a rectangular coordinate type image data supplied from an external host device. A rotary printing apparatus comprising: an image conversion unit configured to convert the image data into image data.

According to the present invention, by providing image conversion means for converting the rectangular coordinate type image data into the rotational coordinate type image data, even if the arrangement pattern of the printing pixels is changed, it is expressed in the rectangular coordinate format. An image having the same appearance as that of the printed image can be formed on the disk print medium. Therefore, it is possible to eliminate the curvature and expansion / contraction of the print image as in the related art, and to realize a high-quality image.

Further, in the present invention, the print head is a line type head in which a plurality of recording elements are arranged in a line at a predetermined pitch, and the main scanning direction intersects the radial direction of the disk print medium at a predetermined angle. It is characterized by doing.

According to the present invention, the printing lines in the main scanning direction intersect at a predetermined angle with the radial direction of the disk print medium, so that the intervals of the printing lines in the sub-scanning direction formed by the respective recording elements are set to the intersection angle Can be shortened by minutes. further,
By appropriately setting the length and the crossing angle of the print pixels formed by the recording elements in the sub-scanning direction, the gap between the print lines in the sub-scanning direction can be set to zero.

[0013] Therefore, a high-density printing can be performed by reducing a plain area, and a pixel density higher than the resolution of the print head can be realized. Further, since the contact length between the line-type head and the disk printing medium is increased, the warpage or deformation of the medium due to the head pressing can be suppressed.

According to the present invention, a plurality of pixels which arrange rectangular coordinate type image data supplied from an external host device in a main scanning direction along a radial direction of a disk printing medium and a sub-scanning direction along a circumferential direction are used. The image is formed on the disk printing medium by converting the image into the rotating coordinate type image data and printing in the main scanning direction of the disk printing medium based on the rotating coordinate type image data while rotating the disk printing medium. This is a rotary printing method characterized in that:

According to the present invention, by converting the rectangular coordinate type image data into the rotational coordinate type image data, even if the arrangement pattern of the print pixels is changed, the same appearance as the image represented in the rectangular coordinate format is obtained. The held image can be formed on the disk print medium. Therefore, it is possible to eliminate the curvature and expansion / contraction of the print image as in the related art, and to realize a high-quality image.

Further, according to the present invention, printing is performed in the main scanning direction using a line-type head in which a plurality of recording elements are arranged in a line at a predetermined pitch, and the main scanning direction is aligned with the radial direction of the disk printing medium. It is characterized by crossing at a predetermined angle.

According to the present invention, the print lines in the main scanning direction intersect at a predetermined angle with respect to the radial direction of the disk print medium. Can be shortened by minutes. further,
By appropriately setting the length and the crossing angle of the print pixels formed by the recording elements in the sub-scanning direction, the gap between the print lines in the sub-scanning direction can be set to zero.

Therefore, the printing can be performed at a high density with a reduced solid area, and a pixel density higher than the resolution of the print head can be realized. Further, since the contact length between the line-type head and the disk printing medium is increased, the warpage or deformation of the medium due to the head pressing can be suppressed.

The present invention also provides an image conversion method for converting rectangular coordinate type image data into rotational coordinate type image data,
The image area of the rotational coordinate type image data is arranged in the image area of the rectangular coordinate type image data, and the radial coordinate c defining the pixel position in the radial direction from the center of the rotational coordinate and the pixel position in the circumferential direction from the rectangular coordinate axis are defined. The rotation coordinate point (r, c) is designated using the angle coordinate r, the orthogonal coordinates of the pixel including the rotation coordinate point among the pixels in the rectangular coordinate system are obtained, and the image data of the rectangular coordinate is converted to the rotation coordinates (r , C) are extracted as image data.

According to the present invention, a circular image area in a rotational coordinate format is arranged in a rectangular image area expressed in a rectangular coordinate format, and rectangular coordinates of a pixel including a desired rotational coordinate point (r, c) are set. Is calculated, the image data of the rectangular coordinates is extracted as image data of the rotational coordinates (r, c), and such an operation is performed over all or a part of the range of the radial coordinates c and the angular coordinates r, thereby obtaining the rotation. Can be converted to coordinate type image data.

Further, by rotating and printing the rotational coordinate type image data obtained by such data conversion on a disk printing medium, an image having the same appearance as the image expressed in the rectangular coordinate format can be formed on the medium.

[0022]

FIG. 1 is a perspective view illustrating a thermal recording system according to the present invention. The rotary printing apparatus 10 includes a thermal head 11, a backup roller 12, and cathode tubes 13, 14, and performs printing on a disk print medium M. The disc printing medium M is a disc-shaped printing medium having a thermosensitive coloring layer that develops a color when heat is applied. The thermal head 11 is a line type thermal head extending in the radial direction of the disk print medium M. The stepping motor 15 drives the disk print medium M to rotate around its axis. The backup roller 12 is a roller whose surface is covered with rubber and which supports the disk printing medium M from the back side in response to pressure from the surface by the thermal head 11, and rotates with the rotation of the disk printing medium M. The cathode tubes 13 and 14 emit ultraviolet rays having a wavelength for fixing the coloring layer of the disk print medium M.

Such a rotary printing apparatus 10 uses the radial direction of the disk print medium M as the main scanning direction, the circumferential direction of the disk print medium M as the sub-scan direction, and the radial direction and the circumferential direction of the disk print medium M. The printing is performed by selectively supplying heat to the pixel regions arranged in a color and causing the color to develop.

Incidentally, the thermal head 11 in FIG. 1 may be constituted by a serial head which can scan in the radial direction of the disk print medium M. Further, a turntable can be used instead of the backup roller 12 in FIG.

FIG. 2A is a cross-sectional view showing the structure of a thermal printing sheet 21 used as the disk print medium M in FIG. 1, and FIG. FIG. 2 is a cross-sectional view illustrating the structure of a medium 19 in which the present invention has been performed.

The thermal printing sheet 21 shown in FIG. 2A has the same cross-sectional structure as the multicolor thermal recording sheet described in JP-A-3-43293 and JP-A-5-69566. A printing method in which heat is applied to the multicolor heat-sensitive recording sheet to form a color and print is called a TA (Thermo-Auto Chrome) method. The rotary printing apparatus 10 of the present embodiment is also a TA printing apparatus.

The thermal printing sheet 21 is made of a substrate 22 such as paper.
Is formed with a thermosensitive coloring layer 23 on the surface thereof, and its planar shape is a disk shape. The thermosensitive coloring layer 23 includes a yellow coloring layer 23a, a magenta coloring layer 23b, and a cyan coloring layer 23c.

The yellow coloring layer 23a contains a yellow dye material and a coupler encapsulated in microcapsules,
When a heat energy of 20 mJ / mm ² or more is applied, the two pass through the microcapsules and react to form a color. The yellow coloring layer 23a has a wavelength of 420
Irradiation with ultraviolet light of nm causes the unreacted yellow dye material to be decomposed and no longer develops color.

The magenta coloring layer 23b contains a magenta coloring material and a coupler encapsulated in microcapsules,
When a thermal energy of 40 mJ / mm ² or more is applied, the two pass through the microcapsules and react to form a color. The magenta coloring layer 23b has a wavelength of 365.
Irradiation with ultraviolet light of nm causes the unreacted magenta dye material to be decomposed and no longer develops color.

The cyan coloring layer 23c contains a dye encapsulated in microcapsules and develops a color when heat energy of about 80 mJ / mm ² or more is applied.

The thermal head 11 shown in FIG.
mJ / mm ² ~40mJ / mm ² of the heat energy, 40m
J / mm ² -80 mJ / mm ² of heat energy and 80
It can be supplied either thermal energy of the thermal energy of ^{mJ / mm 2 ~120mJ / mm 2} . The cathode tube 13
In order to fix the yellow coloring layer 23a, a wavelength of 420 n
m ultraviolet rays. The cathode tube 14 includes the magenta coloring layer 2.
In order to fix 3b, an ultraviolet ray having a wavelength of 365 nm is emitted.

The medium 19 shown in FIG. 2B is a medium in which a thermal printing sheet 21 is adhered to a printing surface 20a of an optical disk 20 such as a CD-R via an adhesive layer 24.

The optical disk 20 is formed by laminating an organic dye layer 25, a reflective layer 26 made of metal, and a protective layer 27 on a polycarbonate substrate 30 in this order. In the optical disk 20, data is recorded by irradiating a laser beam from the recording surface 20b to change the phase of the organic dye layer 25. The optical disc 20 that can be used in the rotary printing apparatus 10 includes:
Not limited to such a configuration, for example, CD, CD
-ROM, CD-RW (ReWritable), etc. DVD (Digital Video Disk) -ROM, DVD-R
AM (Random Access Memory), DVD-R, DVD-
RW or the like may be used.

As the disk printing medium M, the thermal printing sheet 21 shown in FIG.
The medium 19 of (b) may be used. Thermal printing sheet 2
When 1 is used as it is, the thermal printing sheet 21 can be attached to the optical disc 20 after printing. Also,
The thermosensitive coloring layer 23 may be formed directly on the optical disc 20 by vapor deposition or the like.

FIG. 3 is a block diagram showing an electrical configuration of the rotary printing apparatus 10. Interface (I / F) 6
Reference numeral 4 denotes data transmission with an external host such as a personal computer through parallel communication or serial communication, for example, receiving image data to be printed from the external host, or transmitting status data indicating the operation status of the apparatus 10. I do. The CPU (Central Processing Unit) 61
It operates according to a predetermined program stored in an M (read only memory) 62 or the like, and controls signal processing for the thermal head 11 and overall operations such as the operation of the stepping motor 15 and the cathode tubes 13 and 14. The ROM 62 includes a CPU 61
This is a non-volatile memory for storing programs and various data.

The RAM 63 is a volatile memory for storing print data and various data, and also functions as a buffer memory for continuously developing image data. Also,
The function of the buffer memory for data expansion may be performed by the memory of the external host, so that the memory capacity of the device 10 may be reduced.

FIG. 4 is a timing chart showing the operation of the rotary printing apparatus 10. FIGS. 5 (a) to 5 (f) are diagrams showing the printing state of the disk printing medium M in a stepwise manner. When printing is started, print image data created by an external host is transmitted to the thermal head 11 via the I / F 64 and the CPU 61. At the same time, energization of the stepping motor 15 starts, and the stepping motor 1
Numeral 5 rotates the disk print medium M at a constant rotation speed.

First, in FIG. 5A, energization of the thermal head 11 is started, and thermal energy of the minimum thermosensitive coloring level is applied to the disk print medium M. As a result, the yellow coloring layer 23a develops a color. Next, as shown in FIG. 5B, when the leading line 73 of the colored region 75 of the yellow coloring layer 23a reaches the last portion 71b of the light irradiation region 71, the current supply to the cathode tube 13 is started. . As a result, the light from the cathode tube 13 is applied to the disk print medium M. The light irradiation area 71 is an area where light from the cathode tube 13 is irradiated. Next, when the head line 73 reaches the thermal head 11 again, the energization of the thermal head 11 is terminated, and the coloring of the yellow coloring layer 23a is terminated.

Next, as shown in FIG. 5C, when the leading line 74 of the fixed area 77 in which the yellow coloring layer 23a has been fixed reaches the thermal head 11, energization to the thermal head 11 is started. Then, the thermal energy of the second lowest thermosensitive coloring level is applied to the disk print medium M. As a result, coloring of the magenta coloring layer 23b starts from the first line 74. Next, the top line 73 of the yellow-colored area is again the last part 71 of the light irradiation area 71.
When the current reaches b, the power supply to the cathode tube 13 is terminated,
The fixing of the yellow coloring layer 23a ends.

Next, as shown in FIG. 5D, the first line 7 of the colored area 79 in which the magenta coloring layer 23b is colored.
When 4 reaches the rear end 72 b of the light irradiation area 72, energization of the cathode tube 14 is started. As a result, the light from the cathode tube 14 is irradiated on the disk print medium M, and the magenta coloring layer 23b is fixed. The light irradiation area 72 is an area where light from the cathode tube 14 is irradiated. Next, when the head line 74 reaches the thermal head 11, the energization of the thermal head 11 is terminated, and the magenta coloring layer 23 is turned off.
The coloring of b ends.

Next, as shown in FIG. 5E, when the leading line 78 of the fixed area 81 where the magenta coloring layer 23b has been fixed reaches the thermal head 11, the thermal head 11 is energized. Starting, the thermal energy of the maximum thermosensitive coloring level is applied to the disk print medium M. As a result, coloring of the cyan coloring layer 23c is started from the first line 78. Next, when the leading line 74 of the magenta-colored area reaches the rear end 72b of the light irradiation area 72 again, the power supply to the cathode tube 14 is terminated, and the fixing of the magenta coloring layer 23b is terminated.

Next, as shown in FIG. 5 (f), when the head line 78 reaches the thermal head 11 again, the power supply to the thermal head 11 is terminated and the cyan coloring layer 23c is turned off.
The coloring of is ended. At this time, the disk printing medium M is entirely covered with the colored area 82 in which the cyan coloring layer 23c has developed color, and printing is completed.

As described above, the coloring and fixing of the yellow coloring layer 23a, the coloring and fixing of the magenta coloring layer 23b,
In addition, by sequentially coloring the cyan coloring layer 23c,
Full color printing can be performed.

FIG. 6 is an explanatory diagram showing a first embodiment of the present invention. The thermal head 11 has a plurality of heating elements arranged in a line, and is arranged along the radial direction of the disk printing medium M. The printing operation is performed while the disk printing medium M rotates clockwise around the rotation center O. Perform

When printing is started, the thermal head 11 moves the outermost pixels P along the first main scanning line (r = 1).
A total of HDN pixels from (1, 1) to the innermost pixel P (HDN, 1) are printed. Next, the disk print medium M is rotated by the sub-scanning pitch of the pixels, and the thermal head 11 is rotated.
Is the outermost pixel P along the second main scanning line (r = 2)
Pixels from (1, 2) to the innermost pixel P (HDN, 2) are printed. By repeating the main scanning printing and the step rotation in this manner, the outermost pixel P (1, SLN) along the last main scanning line (r = SLN) is shifted from the innermost pixel P (H
When the pixels up to DN, SLN) are printed, printing for one round is completed. When performing the above-described full-color printing, printing for three rounds is performed corresponding to the three primary colors.

Here, the pixel P (c, r) means a pixel specified by the rotational coordinates of the r-th main scanning line and the c-th sub-scanning line, and HDN is the effective printing width in the annular printable area. Is a numerical value represented by the number of pixels, and DIN is a numerical value representing the invalid printing width inside the innermost circumference by the number of pixels.
SLN is the number of sub-scan lines for one round of the disk print medium M. Therefore, HDN ×
A print image consisting of SLN pixels is formed. For example, if the pitch of the printing pixels in the main scanning direction is 200 dpi, HDN = 320 pixels and SLN = 2940 lines.

FIG. 7 is an explanatory diagram showing an image conversion method for converting rectangular coordinate type image data into rotational coordinate type image data. A rectangular image area Q indicating the arrangement of the rectangular coordinate type image data is represented by X in the right direction with the origin (0, 0) at the upper left corner of the image.
It is expressed in an orthogonal coordinate format having an axis and a Y axis in a downward direction. Such rectangular coordinate type image data is supplied from an external host device.

In order to extract rotational coordinate type image data necessary for printing the disk printing medium M from the image area Q,
A circular image area U is arranged. The image area U has a radius corresponding to the number of pixels (= HDN + DIN) from the rotation center O (Xo, Yo) to the outermost first sub-scanning line.
The square area circumscribing the image area U is defined by points P1 (X1, Y1) and P2 (X2, Y2) of the rectangular coordinates. The area corresponding to the invalid print width on the inner side is unnecessary for printing on the disk print medium M, and may be excluded.

Next, the image data Pixel of the pixel P (c, r)
A method for extracting lData (c, r) will be described. The image data PixelData (c, r) can be expressed by the following equation using the rectangular coordinates X and Y.

[0050]

(Equation 1)

Here, L is a numerical value representing the radius from the rotation center O to the pixel P by the number of pixels, θ is the counterclockwise angle from the X-axis direction to the pixel P, and INT is the calculation result. It is a function that rounds down the decimal point and converts it to an integer.

First, when obtaining image data of the pixel P (c, r), L is calculated by substituting the radial coordinate c into the equation (4), and substituting the angle coordinate r into the equation (5) to obtain θ. calculate. Next, L and θ are substituted into the equations (1) and (2) to obtain the orthogonal coordinates (X, Y) of the pixel including the rotational coordinate point (r, c). Then, the image data of the pixel specified by the rectangular coordinates (X, Y) is extracted as image data PixelData (c, r). These operations are performed by using radial coordinates c and angular coordinates r.
By doing over all or part of the
It can be converted to rotation coordinate type image data.

FIG. 8A is a flowchart showing an image conversion method, and FIG. 8B is a flowchart showing the entire process of rotary printing. First, step a1 in FIG.
In, the buffer address Buf_ADRS is set to the top address TOP_ADRS of the empty memory area in order to secure a buffer area for storing rotational coordinate type image data. Next, in steps a2 and a3, the angle coordinate r is set to 1 as a sub-scanning counter, and the radial coordinate c is set to 1 as a main scanning counter. Next, in step a4, the rotational coordinates (r, c) are converted into rectangular coordinates (X, Y) using equations (2) to (5), and in step a5, the pixel specified by the rectangular coordinates (X, Y) Image data to image data
Extracted as PixelData (1,1) and buffer address Buf_
Store in the ADRS memory area. Next, in step a6, the buffer address Buf_ADRS is increased by one, and
Increases the radius coordinate c by one. In step a8, it is determined whether or not the radial coordinate c has exceeded the effective print width HDN, that is, whether or not the conversion for one main scanning line has been completed.
At present, since c = 2, the flow returns to step a4, where the image data PixelData (2,1) is extracted and the buffer address Bu is read.
Store in f_ADRS. Pixels for the first main scanning line
Image data from lData (1,1) to PixelData (HDN, 1) is extracted and stored in a buffer.

Next, in step a9, the angle coordinate r is incremented by one, and in step a10, it is determined whether or not the angle coordinate r has exceeded the number of sub-scanning lines SLN for one rotation, that is, whether or not all conversions have been completed. judge. Currently, because r = 2,
Returning to step a3, PixelDat for the second main scanning line
Image data from a (1,2) to PixelData (HDN, 2) is extracted and stored in a buffer.

In this way, the pixels for all the main scanning lines
When the image data from lData (1,1) to PixelData (HDN, SLN) is stored in the buffer, the image conversion for one round ends.

The image conversion described above corresponds to the processing in step b1 in FIG. 8B, and in step b2, the gradation level of the converted rotational coordinate type image data matches the gradation characteristic of the printing process. Therefore, gamma correction is performed on the image data. In step b3, the density unevenness caused by the inner and outer peripheral speed difference of the disk print medium M is corrected. This is to eliminate the density unevenness in which the peripheral speed of the disk print medium M increases from the inner periphery to the outer periphery, so that the print density on the inner peripheral side is high and the print density on the outer peripheral side is reduced. In step b4, the density unevenness caused by the thermal history before starting the printing operation of the thermal head 11 is corrected. This is because when printing is started in a state where the temperature of the thermal head 11 is high, excessive heat is applied to the recording medium, or conversely, when printing is started in a state where the thermal head 11 is cooled, the heat applied to the recording medium is reduced. This is to eliminate uneven density such as lack of density.

Thus, the rectangular coordinate type image data supplied from the external host device is converted into rotational coordinate type image data, and after various data corrections, the image represented in rectangular coordinate format by rotational printing of the thermal head 11 is output. An image having the same appearance can be formed on the disk print medium M.

FIGS. 9 and 10 are explanatory diagrams showing a second embodiment of the present invention. The thermal head 11 has a plurality of heating elements arranged in a line, and is disposed obliquely so as to intersect at a predetermined angle with respect to the radial direction of the disk print medium M. The printing operation is performed while rotating clockwise.

As shown in FIG. 9A, for example, when the heating elements 11a of the thermal head 11 are arranged at 200 dpi, the pitch of the heating elements 11a is 0.125 mm (= 2 mm).
(5.4 mm / 200). The heating element 11a has a main scanning dimension of 0.105 mm and a sub scanning dimension of 0.175 mm.
In the case of forming a rectangle, the gap between the heating elements 11a is 0.0
2 mm. Therefore, when the thermal head 11 is arranged in parallel with the radial direction of the disk print medium M, a gap of about 0.02 mm also occurs in the print line in the sub-scanning direction.

Although such a gap is not particularly noticeable depending on the type of the image, it is necessary to eliminate the gap when a higher quality image is required. As a countermeasure against this, the thermal head 11 is arranged obliquely,
The sub-scanning dimension of a is set to 0.125 mm. As shown in FIG. 9C, the diagonal line (length: 0.204 mm) of the heating element 11a is shifted from 59 degrees to 52.
By inclining at 4 degrees, the projected size of the diagonal is 0.125 mm (= 0.204 mm × cos 52.4).
°).

As shown in FIG. 10, when printing is started,
The thermal head 11 moves from the outermost pixel P (1,1) to the innermost pixel P (HD) along the first main scanning line (r = 1) obliquely intersecting the radial direction of the disk print medium M.
Print a total of HDN pixels up to N, 1). Next, the disk print medium M rotates by the sub-scanning pitch of the pixels, and the thermal head 11 moves from the outermost pixel P (1,2) to the innermost pixel along the second main scanning line (r = 2). Pixel P (HD
The pixels up to N, 2) are printed. By repeating the main scanning printing and the step rotation in this manner, the last main scanning line (r =
When the pixels from the outermost peripheral pixel P (1, SLN) to the innermost peripheral pixel P (HDN, SLN) along the SLN) are printed, one round of printing is completed. When performing the above-described full-color printing, printing for three rounds is performed corresponding to the three primary colors.

Here, the pixel P (c, r) means a pixel specified by the rotational coordinates of the r-th main scanning line and the c-th sub-scanning line, and HDN is the heating element 1 of the thermal head 11.
1a, DN is a numerical value representing the effective print width in the annular printable area by the number of pixels, DIN is a numerical value representing the invalid print width inside the innermost circumference by the number of pixels, and SLN Is the number of sub-scanning lines for one round of the disk print medium M. Therefore, on one side of the disk print medium M, HD
A print image consisting of N × SLN pixels is formed.

FIG. 11 is an explanatory diagram showing an image conversion method for converting rectangular coordinate type image data into rotational coordinate type image data when the thermal head 11 is arranged obliquely. FIG.
2 is an explanatory diagram of parameters appearing in the calculation formula. A rectangular image area Q indicating the arrangement of the rectangular coordinate type image data is represented in a rectangular coordinate format having an X axis in the right direction and a Y axis in the downward direction with the upper left corner of the image as the origin (0, 0). Such rectangular coordinate type image data is supplied from an external host device.

In order to extract rotational coordinate type image data necessary for printing the disk printing medium M from the image area Q,
A circular image area U is arranged. The image area U has a radius corresponding to the number of pixels (= HDN + DIN) from the rotation center O (Xo, Yo) to the outermost first sub-scanning line.
The square area circumscribing the image area U is defined by points P1 (X1, Y1) and P2 (X2, Y2) of the rectangular coordinates. The area corresponding to the invalid print width on the inner side is unnecessary for printing on the disk print medium M, and may be excluded.

Next, the image data Pixel of the pixel P (c, r)
A method for extracting lData (c, r) will be described. The image data PixelData (c, r) can be expressed by the following equation using the rectangular coordinates X and Y.

[0066]

(Equation 2)

Here, L1 to L4 are parameters shown in FIG. 12, θ is a counterclockwise angle from the X-axis direction to the pixel P, and α is the outermost pixel P and the innermost pixel P Is the angle formed by the rotation center O, and INT is a function that rounds off the decimal part of the operation result to convert it into an integer.

First, when obtaining the image data of the pixel P (c, r), L1 to L4 are calculated by substituting the radial coordinate c into the equations (15) to (18), and the angle coordinate r is calculated according to the equation (14). To calculate θ. Next, L1 to L4 and θ are expressed by the formula (1).
2) and (13), the orthogonal coordinates (X, Y) of the pixel including the rotation coordinate point (r, c) are obtained. Then, the image data of the pixel specified by the rectangular coordinates (X, Y) is extracted as image data PixelData (c, r). By performing such an operation over all or a part of the range of the radial coordinate c and the angular coordinate r, the image data can be converted into rotational coordinate type image data.

The image conversion method described above may be executed by the CPU 61 of the rotary printing apparatus.
It is also possible to configure so that an external host device such as a personal computer having a U and a large-capacity memory takes charge of image conversion and transmits the obtained rotational coordinate type image data to the rotary printing device.

[0070]

As described above in detail, according to the present invention, even if the arrangement pattern of the print pixels changes from the rectangular coordinate format to the rotational coordinate format, an image having the same appearance as the image represented in the rectangular coordinate format is obtained. It can be formed on a disk print medium. Therefore, it is possible to eliminate the curvature and expansion / contraction of the print image as in the related art, and to realize a high-quality image.

Further, since the printing lines in the main scanning direction intersect at a predetermined angle with the radial direction of the disk printing medium, the interval between the printing lines in the sub-scanning direction can be set to zero. High density printing is possible, and a pixel density higher than the resolution of the print head can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a thermal recording system according to the present invention.

FIG. 2A is a cross-sectional view showing a structure of a thermal printing sheet 21 used as a disc printing medium M in FIG. 1, and FIG.
FIG. 3 is a cross-sectional view illustrating a structure of a medium 19 attached to the medium 0.

FIG. 3 is a block diagram illustrating an electrical configuration of the rotary printing apparatus 10;

FIG. 4 is a timing chart showing the operation of the rotary printing apparatus 10.

FIG. 5 is a diagram showing a printing state of the disk print medium M in a stepwise manner.

FIG. 6 is an explanatory diagram showing the first embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an image conversion method for converting rectangular coordinate type image data into rotational coordinate type image data.

8A is a flowchart illustrating an image conversion method, and FIG. 8B is a flowchart illustrating an entire process of rotary printing.

FIG. 9 is an explanatory diagram showing a second embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a second embodiment of the present invention.

FIG. 11 is an explanatory diagram showing an image conversion method for converting orthogonal coordinate type image data into rotational coordinate type image data when the thermal head 11 is arranged obliquely.

FIG. 12 is an explanatory diagram of parameters appearing in a calculation formula.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotary printing apparatus 11 Thermal head 12 Backup roller 13, 14 Cathode tube 15 Stepping motor 20 Optical disk 21 Thermal printing sheet M Disk printing medium

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Norihiro Sawamoto 20-10 Nakayoshida, Shizuoka City, Shizuoka Prefecture Star Precision Co., Ltd. F-term (reference) BB22 BB32 BC03 CA23 DA43 DA58 EA01 FA03 FA09 FA35 FA43

Claims (5)

[Claims] 1. A print head for printing in a main scanning direction along a radial direction of a disk print medium, and a medium for rotating the disk print medium in a sub-scan direction along a circumferential direction of the disk print medium. A rotating unit, and an image for converting the orthogonal coordinate type image data supplied from the external host device into rotational coordinate type image data composed of a plurality of pixels arranged in the main scanning direction and the sub-scanning direction of the disk print medium. A rotary printing apparatus comprising: a conversion unit. 2. The print head is a line type head in which a plurality of recording elements are arranged in a line at a predetermined pitch, and a main scanning direction intersects a radial direction of a disk print medium at a predetermined angle. The rotary printing apparatus according to claim 1, wherein: 3. A plurality of pixels arranged in a main scanning direction along a radial direction of a disk printing medium and a sub-scanning direction along a circumferential direction of rectangular coordinate type image data supplied from an external host device. Convert to rotating coordinate type image data,
A rotating printing method characterized in that an image is formed on a disk print medium by printing in the main scanning direction of the disk print medium based on the rotating coordinate type image data while rotating the disk print medium. 4. A printing apparatus in which printing is performed in a main scanning direction using a line type head in which a plurality of recording elements are arranged in a line at a predetermined pitch, and wherein the main scanning direction is formed at a predetermined angle with respect to a radial direction of a disk print medium. 4. The rotary printing method according to claim 3, wherein the prints intersect. 5. An image conversion method for converting rectangular coordinate type image data into rotational coordinate type image data, comprising: arranging an image region of rotational coordinate type image data in an image region of rectangular coordinate type image data; A rotation coordinate point (r, c) is designated by using a radial coordinate c defining a pixel position in a radial direction from the center and an angular coordinate r defining a pixel position in a circumferential direction from an orthogonal coordinate axis, and specifying a pixel in a rectangular coordinate system. An image conversion method comprising: obtaining orthogonal coordinates of a pixel including the rotation coordinate point; and extracting image data of the orthogonal coordinates as image data of rotation coordinates (r, c).