JPH10817A - Calibration adjusting method of color printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically reduce the time for adjusting calibration by correcting testing image data only with printer condition correction data, and outputting the corrected testing image data from a color printer without having color correction by a synthetic table. SOLUTION: A printer condition correction data number K is set to be 1 by an editing device (200). Test chart data for calibration is read out on a RAM by the CPU of the editing device (202), and the printer condition correction data k are read out on the RAM by the CPU (204). The test chart data are corrected by the printer condition correction data k (206). The corrected test chart data are sent to the color printer (208), and the color printer outputs by printing the inputted test chart data without conducting the color conversion by a synthetic LUT (210). Accordingly, the time for adjusting calibration can be drastically reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the calibration of a color printer, and more particularly, to a method for calibrating a color printer including a halftone image before producing a color print using a color printer using a rotary press or the like. The present invention relates to a calibration adjustment method for a color printer that prints a print proof image.

[0002]

2. Description of the Related Art In a color printing machine using a rotary press or the like,
A color print using a so-called halftone image is created. Before creating the color print, a color print proof image (also referred to as a color print proof) is created in advance by a color printer having a simple configuration, and the image is created. Based on this, proofreading of color printing is performed. By using this color printer, it is not necessary to make a plate making film and a printing plate (PS plate) for a color printing machine at the time of proofreading, and an image is easily formed on a sheet several times in a short time. A hard copy can be made, and the proofreading work can be made much more efficient.

By the way, before a color print proof image for proofreading is created, a density difference between a print output and a color print resulting from a printer condition such as a machine difference of a color printer or a change over time is corrected in advance. It is necessary (called calibration adjustment).

For example, as shown in FIG. 13A, the relationship between the output density and the printer signal input to the output unit is designed to be an output density curve 140 of a reference gradation indicated by a dashed line. Also, in the printer, an output density curve whose characteristics are different from the output density curve 140 with the individual difference of the apparatus or the passage of time, for example, the output density curve 1 shown by a solid line
It changes to 42. In this case, even if a printer signal P ₁ or P ₂ then inputted to the output unit of the printer as to obtain the output density D ₁ or D _2, concentrations that are actually output D ₁ 'or D _2', and this remains Cannot output a proper color print proof image.

Therefore, for example, the printer signal P is converted into a signal P 'according to the conversion curve 150 shown in FIG. 13B, and the corrected signal is input to the output unit of the printer, thereby obtaining the output density of the reference gradation. I'm going to get In this conversion curve 150, the printer signals P ₁ and P ₂ before correction become signals P ₁ ′ and P ₂ ′ after correction, and as shown in FIG. However, by inputting the corrected printer signals P ₁ ′ and P ₂ ′, appropriate output densities D ₁ and D ₂ can be obtained.

In this calibration adjustment, theoretically, as the image data, four halftone dot area ratio data (halftone) for each of C (cyan), M (magenta), Y (yellow), and K (black) are used. % Data) is converted by a 4D (4D) conversion table for color correction built in the color printer, and then the data converted by a 1D (1D) conversion table for calibration is printed out.
By comparing with a reference calibration chart (color patch), the calibration 1D
The conversion table is adjusted. That is, in theory, as shown in FIG. 11A, image data is converted using a two-stage table.

However, the actual processing is as shown in FIG.
As shown in (b), the 4D conversion table for color correction and the 1D conversion table for calibration are synthesized into a one-stage table (synthesis table) by the synthesizing means, and the image data is converted by the synthesizing table. As a result, the number of tables is reduced to one, which is advantageous in terms of processing speed of color conversion and saving of memory as compared with the method of performing color correction using the two-stage table.

A calibration adjustment method using such a one-stage synthesis table will be described with reference to the flowchart of FIG.

As shown in FIG. 12, first, the test chart output from the color printer by the combination table and the reference chart indicating the reference gradation are visually compared (step 270). In this comparison, it is determined whether correction is necessary (step 272). If the correction is necessary (Yes at Step 272), the calibration 1D table is corrected (Step 274), and the calibration table corrected by the combining unit and the color correction 4D conversion table are combined (Step 276). ).
Then, the test chart is color-converted by the combined table and output (step 280).
Returning to 0, comparison with the reference chart is performed, and the same processing is repeated. On the other hand, if it is determined in step 272 that correction is not necessary, the color printer prints a color print proof image for calibration based on the synthesis table (step 282). Then, color calibration is performed based on the color print proof image.

[0010]

However, the above-described conventional method of performing calibration adjustment using a one-stage table has the following problems.

In other words, the 1D table for calibration requires a capacity of 256 × 4 = 1024 bytes because the unit of each gradation data (256 gradations) of four colors of CMYK is 1 byte because it is a one-dimensional table.

[0012] In contrast, the color correction 4D conversion table, also the number of gradations of the gradation data as thinned to 33 points, for the 4-dimensional table, 33 ⁴ × 4 ≒ 4.5 M bytes, and the very It will be a large capacity. As a result, much time is spent generating the combination table in step 276 of FIG. 12, and it takes time to adjust the calibration of the color printer.

In view of the above facts, the present invention provides a color printer calibration adjustment method in which the color conversion processing speed is improved by using a one-stage synthesis table and the calibration adjustment time is greatly reduced. The purpose is to provide.

[0014]

In order to achieve the above object, according to the present invention, there is provided at least two types of correction of color correction data for color calibration and printer condition correction data for correcting printer conditions. A calibration adjustment method for a color printer, comprising data and using a one-stage synthesis table obtained by synthesizing the correction data, wherein the correction is performed by correcting test image data only with the printer condition correction data. And an output step of outputting the test image data corrected in the correction step from a color printer without performing color correction by the synthesis table,
It is characterized by consisting of.

According to the first aspect of the present invention, the test image data is corrected only by the printer condition correction data, and the test image data is output by the color printer without performing the color conversion using the synthesis table. The operator determines whether or not the test image output from the color printer is appropriate. If the operator determines that the test image is not appropriate, the operator adjusts the printer condition correction data, and adjusts the adjusted printer condition. The correction process and the output process are repeated for the correction data. When it is determined that the test image is appropriate, at least the printer condition correction data obtained by correcting the test image and the color correction data are synthesized to create the synthesis table. As described above, according to the present invention, while the printer condition correction data is being adjusted, the test image data is corrected using only the printer condition correction data, and the synthesis table is not created. In general, since it takes a long time to create a synthesis table, compared with the related art in which a synthesis table is created every time printer conditions are adjusted, advantages such as saving memory and improving color conversion speed by using a single-stage synthesis table are maintained. The time for calibration adjustment can be greatly reduced without changing the calibration. The color printer outputs a color print proof image for color calibration based on the synthesis table obtained by the calibration adjustment.

According to a second aspect of the present invention, there is provided a color printer according to the first aspect, wherein the color image of the input image data is corrected by the synthesizing table and output, and the input image data is synthesized. And a second output path for outputting without performing color correction using a table, wherein the test image data corrected in the correction step is output through the second output path.

According to the second aspect of the present invention, the color printer includes:
The test image data corrected in the correction step is output through a second output path. Note that, in a normal case where the adjustment is not calibration adjustment, the color printer performs color correction on the input image data using the synthesis table and outputs the corrected image data. That is, the image data is output through the first output path. As described above, in the present invention, the color printer is provided with two output paths, so that the calibration adjustment can be easily performed without reducing the versatility of the color printer. For example, the color printer may be provided with a means for switching between the first output path and the second output path in accordance with the instruction of the operator or the type of data.

According to a third aspect of the present invention, there is provided the first or second aspect.
The invention is characterized in that the correction step is performed by an editing device connected to a color printer.

According to the third aspect of the present invention, the editing device connected to the color printer corrects the test image data based on the printer condition correction data, and inputs the data to the color printer. Then, the test image data is output by the color printer without performing the color conversion using the combination table. By correcting the test image data by the editing device outside the color printer, the color printer can be simplified and downsized. If the first output path and the second output path of the color printer are switched by switching the connection between the editing device and the color printer, it is not necessary to provide a switching means in the color printer, and the color printer can be downsized. , Can be simplified.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) An embodiment according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a system configuration for producing a color print proof image and a color print. As shown in FIG. 1, a system for creating a color print proof image includes a color printer 12 that outputs a color print proof image 14 for proofing, an editing device 10 that functions as a higher-level device of the color printer 12, and Is provided. As the color printer 12, as described later,
A small-sized printer having a simple configuration such as a so-called thermal printer can be used.

The editing device 10 can be composed of, for example, a personal computer, and controls calibration adjustment of the color printer 12 by sending test chart data, which will be described later, to a color printer 12 connected to the editing device 10. . That is, at the time of calibration adjustment, the color printer 12 generates a test chart 16 for correcting a difference between the color print proof image 14 and the color print 26 which is caused by printer conditions such as machine differences between the color printers. Output. Then, the operator visually compares the test chart 16 with the reference chart 18 printed at the reference gradation, and adjusts printer conditions via the editing device 10 when correction is necessary.

Further, the editing apparatus 10 can be connected to a color printer 20 for outputting a plate making film 22 of layout data subjected to printing conditions and color correction conversion by the editing apparatus. This plate making film 22 is used as a printing plate (PS
By passing through the plate / printing device 24, a color print 26 to be finally obtained is created.

Next, a detailed circuit configuration example of the editing apparatus 10 will be described with reference to FIG. As shown in FIG.
0 is a CPU 30 that controls and manages the entire apparatus based on a predetermined program, a program memory 32 in which the predetermined program is stored, and a work area of the CPU 30 and a storage location of input image data and bitmap data. A RAM 34 to be used, a data memory 42 composed of a nonvolatile memory for storing data, a keyboard (or mouse) 36 as an input means of an operator, a display 38 for displaying processing results and the like, an external input / output And an input / output interface circuit 40 for controlling an input / output interface with a device, each of which is connected to a system bus 46 for transmitting data and instructions.

The data memory 42 stores the color printer 1
Printer condition correction data 44 for correcting printer conditions such as a difference between two devices and a change with time are stored. The printer condition correction data 44 includes data 1,
2,. . . , N, respectively, and each data is the printer condition correction data 1, 2,. . Is set to exactly the same data.

The input / output interface circuit 40 is connected to a color scanner 50 as an external input device and a color printer 12 and a color printer 20 as external output devices.

The color scanner 50 scans an image original 140 as shown in FIG.
The image data is converted into image data for each of the colors (red), G (green), and B (blue), and the data is input to the editing device 10 via the input / output interface circuit 40. The input image data is interpreted by an interpreter (not shown) and is stored in the RAM 34 as layout data in which character data 144, line drawing data 146, and gradation image data 142 are laid out in a print image as shown in FIG. .
The image data may be read from a recording medium such as a magneto-optical disk or a CD-ROM.

The program memory 32 stores, in addition to the control main program, image data R, G, and B read by the color scanner 50 into halftone dot area ratio data Y, M, C, and K. , A subroutine for converting test chart data with the printer condition correction data 44, and the like. Editing device 10
Converts the image data (RGB) sent from the color scanner 50 into halftone dot area ratio data Y, M, C, and K, and outputs it to the color printer 12.

Next, a functional block diagram of the color printer 12 is shown in FIG. As shown in FIG.
2 is provided with a data switching unit 52 for switching the output path of the dot area ratio data Y, M, C, K sent from the editing device 10. The data switching unit 52 identifies the type of the input data based on the header part of the data or an instruction from the operator, outputs the image data of the image document to the first output path 45, and outputs the test chart data to the first output path 45. 2 to the output path 47. Here, the first output path 45 is connected to a color correction calculation unit 58 described later.
Is an output path to a data output unit 62 that prints out image data through the second output path 47.
The output path directly leads to the data output unit 62.

The color correction calculator 58 provided on the first output path 45 combines the dot area ratio data Y, M, C, and K into a composite L
The color is corrected based on the UT 60 and output to the data output unit 62. The synthesis LUT 60 is a four-dimensional table for converting Y, M, C, and K data prepared in advance in a readable / writable nonvolatile memory of the color printer 12, and takes into account an improvement in processing speed of color correction conversion. It is a single-stage table.

In the synthetic LUT 60, if data is prepared for all the gradations (for example, 256 gradations) of the input data, the data becomes extremely large. Therefore, a table corresponding to a smaller number of gradations (for example, 33) is usually used. Has been decimated. In this case, the color correction calculation unit 58
An interpolation operation is performed on intermediate data not prepared at T60.

Further, printing condition correction data 66 for correcting Y, M, C, and K data in accordance with printing conditions for color printing, standard color conversion data 68 for correcting and calibrating image data, And printer condition correction data 70 for correcting printer conditions such as machine differences between color printers
Are data 1, 2, 3,. . . . . A plurality of table formats such as N are prepared in the memory, and the synthesis operation unit 64 can access the memory. The printing condition correction data is, for example, a color printing material type (coated paper, mat coated paper, uncoated paper, etc.) of the color print finally obtained, and a color difference due to a difference in the type of ink used for printing. This is data for correcting the difference.

The synthesizing operation unit 64 selects one of a plurality of data of the printing condition correction data 66, the standard color conversion data 68, and the printer condition correction data 70 based on a command from the editing device 10, respectively. The selected three data are combined in the order of data 66, 68, and 70 to form a combined L
The UT 60 is created.

Here, the conversion based on the data 66, 68, and 70 when Y, M, C, and K are input is set as follows, for example. The outputs of the conversion are Y ', M',
C 'and K'.

[0035] In the printing condition correction data 66, performs Y translation _{'= I y (Y) M} ' = I m (M) C '= I c (C) K' = I k (K). That is, the converted dot area ratio data of each color is a function of only the dot area ratio data of the corresponding color.

[0036] In standard color transformation data _{68, Y '= SM y (} Y, M, C, K) M' = SM m (Y, M, C, K) C '= SM c (Y, M, C, K) Conversion of K ′ = SM _k (Y, M, C, K) is performed. That is, the converted dot area ratio data of each color is a function of the dot area ratio data of all colors.

In the printer condition correction data 70, the following conversion is performed: Y '= _Py (Y) M' = _Pm (M) C '= _Pc (C) K' = _Pk (K) That is, the converted dot area ratio data of each color is a function of only the dot area ratio data of the corresponding color. This functional relationship is represented by the conversion curve 150 in FIG.
It corresponds to.

When the above-described conversion is synthesized by the synthesis operation unit 64, the conversion by the synthesis LUT 60 is as follows.

Y ′ = CM _y (Y, M, C, K) = P _y (SM _y (I _y (Y), M, C, K)) M ′ = CM _m (Y, M, C, K) ) = P _m (SM _m (Y, _Im (M), C, K)) C ′ = CM _c (Y, M, C, K) = P _c (SM _c (Y, M, I _c (C ), K)) K '= CM _k (Y, M, C, K) = P _k (SM _k (Y, M, C, I _k (K))) In the color printer 12 of FIG. Although only color correction and print output of toned image data are shown, character data and line drawing data are also interpreted from the original image data by an interpreter (not shown) and output by the data output unit 62.

Next, the structure of a thermal printer as an example of the color printer 12 is shown in FIG. This thermal printer employs a two-component color developing system using two sheets, an intermediate sheet and an image receiving sheet.

As shown in FIG. 4, the color printer 12
Is covered by a housing 72, and a paper tray 98 on which thermal paper before printing is set is disposed at the bottom of the housing 72. The paper tray 9
The bottom surface of the sheet 8 has a gentle slope that becomes higher in the drawing direction R, and has a constant height near the paper drawing port. A spring 99 for pressing the thermal paper upward is provided at a lower portion of the upper bottom surface.

Further, a semicircular pull-out roller 101 for pulling out the set thermal paper is disposed above the paper tray 98 in the paper pull-out direction R. The drawer roller 101 is normally disposed at a position where the bottom surface is substantially parallel to the sheet surface as shown in the figure, and rotates in the Q direction when the thermal paper is drawn. Due to this rotation, the heat-sensitive paper is successively pinched between the arc-shaped portion of the pull-out roller 101 and the bottom surface of the paper tray 98 pressed by the spring 99 for each sheet, and moves in the pull-out direction R with the rotation of the roller 101.

At the drawer of the paper tray 98, a transport roller 102 for transporting the drawn thermal paper is disposed. At the transport exit side of the roller 102, the thermal paper is guided to the upper right side. An arcuate paper path 103 is provided. A transport roller 104 for further transporting the paper is disposed at the end of the paper path 103, and a transport exit side of the transport roller 104 is an arc-shaped paper path for guiding the thermal paper to the upper left side. 105 is provided. The paper path 105 is disposed so that the position in the lateral direction is substantially the same as the position of the transport roller 102. The heat-sensitive paper pulled out from the paper tray 98 in this manner is drawn from the end of the paper path 105 in a direction opposite to the pull-out direction R in a semicircle.

Near the end of the paper path 105, a guide lever 90 for switching the transport direction of the thermal paper is arranged. The guide lever 90 is rotatable in a P direction around a base shaft 91 by a driving means (not shown), and is normally set to a position 90a when the thermal paper exits from the end of the paper path 105. When the heat starts,
The guide lever 90 is rotated to move from the position 90a to the position 90b.
Is switched to.

On the left side of the guide lever 90, a bottom plate 87 having a gentle inclination substantially at the same height as the base shaft 91 is arranged, and the thermal paper exiting from the paper passage 105 is set at the position 90a. The guide lever 90 guides the bottom plate 87.

A belt drive pulley 8 is provided on the bottom plate 87.
0, a platen roller 82, and a transport belt 92 stretched by the roller 84. The belt driving pulley 80 is supplied with torque by a driving unit (not shown) so as to rotate in the direction T at the time of drawing out the sheet and to rotate in the direction T 'at the start of heat sensing. In response to the rotation of the belt driving pulley 80 in the T and T 'directions,
Rotate in the S and S ′ directions, respectively.

The portion of the transport belt 92 between the belt drive pulley 80 and the rollers 84 forms a paper path together with the bottom plate 87 when the paper is pulled out. A roller 88 is provided. The heat-sensitive paper guided to the bottom plate 87 is nipped by the transport belt 92 and the feed roller 88, and moves with the rotation of the transport belt.

In a portion of the transport belt 92 between the platen roller 82 and the belt driving pulley 80, two feed rollers 86 that are in contact with the transport belt 92 are disposed. , And are moved in the U direction or the U ′ direction by being sandwiched between the feed roller 86 and the transport belt 92 rotating in the S direction or the S ′ direction.

A storage section 105 for storing the upper part of the thermal paper in the middle of thermal recording is disposed at an extension of the transport belt 92 in the U direction. Into the storage part 105,
A drive roller 106 for discharging the toner from the storage unit 105 is provided.

It should be noted that the bottom plate 87 is
Is shaped to draw an arc along the shape of the pulley in the vicinity of
A discharge passage 10 serving as a passage for discharging the thermal paper on which an image is recorded is provided at an upper portion where the end of the arc-shaped bottom plate 87 is extended.
7 are arranged. A discharge roller 108 driven by a driving unit (not shown) is disposed at the end of the discharge passage. The discharge roller 108 draws in the heat-sensitive paper in the discharge passage 107 and discharges the heat-sensitive paper provided in the upper portion of the color printer 12. Discharge to tray 100.

A support arm 76 is disposed below the discharge tray 100. At the tip of the support arm 76, a heating element (not shown) is mounted with an image recording element (not shown) in the main scanning direction (image recording perpendicular to the plane of the drawing). ) Are provided.

Below the support arm 76, a supply roll 74 for supplying a long ink sheet 110 coated with ink for thermal copying for each color is arranged. As shown in FIG. 5B, this ink sheet 110 has
Inks C, M, Y, and C for thermal copying are provided in areas having substantially the same shape and size as the recordable image area of the thermal paper.
K,. . . . Are applied in this order.

Further, a collecting roll 96 for collecting the ink sheet 110 is disposed at the lower end of the discharge tray 100 opposite to the supply roll 74. When the collection roll 96 is rotated in the V direction by a driving unit (not shown), the ink sheets wound around the supply roll 74 are sequentially taken up by the collection roll 96. In the course of collecting the ink sheet 110, a feed roller 94 for arranging the ink sheet 110 at a preferable position is arranged.

The ink sheet 110 is sandwiched between the thermal print head 78 and the transport belt 92 stretched by the platen roller 82, and the thermal paper is transported to the transport belt 92 side of the sandwiched portion. Is done. That is, the ink sheet 110 is disposed between the thermal print head 78 and the thermal paper.

At the time of image recording, each heating element of the thermal print head 76 converts an electric signal corresponding to image data sent from a control unit (not shown) into a heat signal, and the thermal paper is conveyed in the U direction. . The thermal signal of the thermal print head 76 causes a chemical reaction between the ink applied to the ink sheet 110 and the thermal material applied to the thermal paper in accordance with the image, and an image corresponding to the image data is recorded on the thermal paper. .

The housing 7 of the color printer 12
An air cooling window 114 for taking in air for air cooling from the outside is provided at the back of the air conditioner 2, and an air cooling unit 112 having a built-in fan for device air cooling is arranged behind the air cooling window 114. .

FIG. 5A is a perspective view of the supply / recovery system of the ink sheet 110 and the thermal paper transport system.

As shown in FIG. 5 (a), the belt drive pulley 80 rotates in the direction T, and the rotation of the heat-sensitive paper 1
16 is transported in the U direction, and the thermal print head 78
It can be seen that the image is formed by the thermal transfer to the ink sheet 110 and the thermal paper 116 by the above. Further, since the image data is separately supplied as dot area ratio data C, M, Y, and K, the inks C, M shown in FIG.
The collection roll 96 is rotated in the V direction so that any one of M, Y, and K is thermally transferred to the thermal paper 116 in accordance with the dot area ratio data of the corresponding color, so that the collection roll 96 is always arranged at an appropriate position ( In the example of FIG. 5A, the ink sheet is “K”.

By the way, CMY is applied to one thermal paper 116.
In order to thermally transfer all of the K4 color inks, when one color is thermally transferred, the thermal paper 116 is returned to the position at the start of image recording, and the ink sheet 110 is arranged so that the next color is transferred. Therefore, a total of four image recordings are required, such as performing image recording again for the next color.
For this reason, the color printer 12 employs a transport system called a switchback system. Hereinafter, the transport path of the thermal paper in this transport format will be described with reference to FIGS. 6 (a) to 6 (e). In each of the drawings, the transport path of the thermal paper is indicated by a thick line.

As shown in FIG. 6A, first, the thermal paper set in the paper tray 98 is pulled out of the drawer roller 10.
1 and the transport rollers 102 and 104
With the rotation of, the paper reaches the guide lever 90 while drawing a semicircle via the paper passages 103 and 105. At this time, since the guide lever 90 is set at the position 90a, the paper path 1
05 is inserted into the passage between the bottom plate 87 and the conveyor belt 92, and the conveyor belt 9 rotating in the S direction is
2 advances in the I direction along the bottom plate 87.

When the heat-sensitive paper that has advanced in the direction I reaches the arc-shaped portion at the end of the bottom plate 87, it rises along the arc and is inserted into the discharge passage 107 disposed above it, as shown in FIG.
As shown in (2), the leading end stops at a position immediately before the discharge roller 108. At this time, the guide lever 90 is moved to the position 90a.
To the position 90b, and the transport belt 92 rotates in the opposite direction S ′.

The heat-sensitive paper set at the position shown in FIG. 6B advances in the direction I ', which is opposite to the direction of pulling out, along the conveyor belt 92 rotating in the direction S', and is switched to the position 90b. Ascending along the lever 90, the thermal recording is started when the leading end is inserted into a position sandwiched between the thermal print head 78 and the platen roller 82. At the start of recording, the position of the ink sheet 110 is arranged such that any ink area (for example, “C”) of the ink sheet 110 matches the recording area of the thermal paper.

As shown in FIG. 6C, the thermal paper during thermal recording advances in the J direction, and the ink sheet 110 is also supplied from the supply roller 74 in accordance with the advance. At this time, image data signals (C, M,
Y or K) is sent to the thermal print head 78, which converts the thermal print head 78 into a thermal signal corresponding to an image. The heat signal causes the ink sheet 1
A reaction occurs between the ink on 10 and the substance applied to the thermal paper, and an image of the corresponding color is recorded on the thermal paper as it proceeds in the J direction. As shown in FIG. 6C, the leading end of the thermal paper that has advanced in the J direction is
As a result, a part thereof is drawn into the housing portion 105.

When the image of the color is recorded in all of the image areas of the thermal paper, the transport belt 92 rotates in the S direction, whereby the thermal paper is reversed from the position of the thick line in FIG. It is stored at the position before the thermal recording indicated by the dotted line in FIG. Here, the position of the ink sheet 110 is reset so that the ink area of the color to be recorded next matches the recording area of the thermal paper. Then, in the same manner, the transport belt 92 rotates again in the S 'direction, the thermal print head 78 converts the image data of the next color into a heat signal, and the image of the color is recorded on the thermal paper. Thus, C of the ink sheet 110,
Thermal recording is repeated four times each for the M, Y, and K ink areas (switchback method).

When an image is recorded for the C, M, Y, and K image data, the transport belt 92 rotates in the S direction at the position before the image recording indicated by the dotted line in FIG. Rises through the discharge passage 107. And FIG.
As shown in (d), when the leading end reaches the discharge roller 108, the discharge roller
It is discharged at 00.

As shown in FIG. 6E, the discharge tray 10
When the ejection of the image-recorded thermal paper to 0 is completed, the guide lever 90 is switched from the position 90b to the position 90a.

Next, in the system shown in FIG.
The procedure for performing the calibration adjustment 2 will be described below with reference to the flowchart in FIG.

As shown in FIG. 7, first, the editing device 10
Sets the printer condition correction data number k to 1 (step 200). The printer condition correction data number k is a number (data 1, 2, 3,...) Sequentially assigned to the plurality of printer condition correction data 44 stored in the data memory 42 of the editing device 10. N), each of which corresponds to the number of the printer condition correction data 70 of the corresponding color printer 12. If the correction data of the optimum or near printer condition is known in advance, the number of the correction data may be initially set, and the number k may not necessarily be set to 1.

Next, the CPU 30 of the editing device 10
The test chart data for calibration is read out onto the memory 34 (step 202). This test chart data is data that becomes a test chart as shown in FIG. 14 at the time of printing, and K, C,
It consists of M and Y data. The test chart in FIG.
The dot area ratio (%) of each of K, C, M, and Y color data is 0%.
The printout is made in a square area from 5% to 100% in 5% steps. The test chart data is obtained by reading and inputting a test chart print prepared in advance by the color scanner 50. Of course, it may be stored in the data memory 42 in advance.

Next, as shown in FIG.
The printer condition correction data k is read out to the AM 34 (step 204). Here, since k is set to 1 in step 200, the printer condition correction data 1 is read. Although the printer condition correction data is stored in the data memory 42, the printer condition correction data 70 of the color printer 12 may be read.

Next, the test chart data read in step 202 is corrected by the printer condition correction data k read in step 204 (step 20).
6). This correction, Y correction before the test chart data, M, C, K _{data, TY = P y (Y)} TM = P m (M) TC = P c (C) TK = P k (K) and the correction Is done. The test chart data of FIG.
There are only 4 = 84, which can be corrected in a very short time.

Then, the corrected test chart data is sent to the color printer 12 via the input / output interface circuit 40 (step 208). Here, the fact that the test chart data is a test chart is described in the head portion of the test chart data to be transmitted, so that the color printer 12 can distinguish it from normal image data.

Next, the color printer 12 sets the composite LUT 6
The inputted test chart data is printed out without performing the color conversion by 0 (step 210). That is, the data switching unit 52 in FIG. 3 identifies that the input data is the test chart data TY, TM, TC, and TK, and sends the data directly to the data output unit 62 via the second output path 47. The data output unit 62 performs image recording for each color in the switchback format shown in each drawing of FIG. 6, and outputs the test chart of FIG.

Next, it is determined whether or not there is an input from the operator to the editing apparatus 10 (step 212). If there is no input (step 212 negative determination), the process waits without performing the next processing. Here, the operator checks the printed test chart and FIG.
Is visually compared with the reference data in the same format, and the next process based on the comparison result is instructed using the keyboard or mouse 36 of the editing device 10.

When there is an input from the operator (Yes at Step 212), the editing device 10 analyzes the input and determines whether or not the correction of the printer condition is requested (Step 214). .

If it is determined that the request is a correction request (Yes at step 214), that is, if the difference between the test chart and the output density of the reference data is equal to or more than a certain value,
Update printer condition correction data number k (step 2
16). In this update, other than simply incrementing the number, correction data to be tested next may be selected according to how much the output density of the test chart differs from that of the reference data. Then, the process returns to step 204, and the same processing is executed for the updated printer condition correction data of the number k.

On the other hand, if it is determined in step 214 that the request is not a correction request, that is, if the difference between the test chart and the output density of the reference data does not exceed a certain value,
A composite LUT 60 is created by synthesizing the print condition correction data for the color printer 20 that has already been specified, the standard color conversion data, and the printer condition correction data k determined in the above processing by the synthesis operation unit 64. Then, the calibration adjustment is completed (step 218).

As described above, in the calibration adjustment method according to the present embodiment, each time the printer condition correction data is updated, a large-capacity synthetic LUT 60 is not created as in the related art, but a very small-capacity data is created. Based on the test chart corrected only with the printer condition correction data, appropriate printer condition correction data is determined.
The UT 60 is created. Thereby, the calibration adjustment can be performed in a very short time.

When the calibration adjustment is completed, a color print proof image is created, color calibration is performed, and a color print by a color printing machine is created. The flow of this processing will be described with reference to the flowchart of FIG.

As shown in FIG. 8, when a color print proof image is created (Yes at step 230), the color scanner 50 reads an image original for the color print proof image and edits the image data R, G, and B into an editing device. 10 (step 232).

Next, the editing device 10 converts the image data R, G, and B into halftone dot area ratio data Y, M, C, and K and inputs the data to the color printer 12 (step 23).
4).

In the color printer 12, the data switching unit 52 in FIG. 3 identifies that the image data is for a color print proof image, and sends the input data to the color correction calculation unit 58 via the first output path 45. The color correction calculation unit 58 sends the print conditions, color correction for calibration, and color correction based on the composite LUT 60 created by the calibration adjustment in FIG.
Then, color correction is performed in consideration of the printer conditions (step 236). The color correction calculation unit 58 performs an interpolation calculation as needed (see FIG. 3).

Then, the data output section 62 of the color printer 12 outputs the color print proof image data color-corrected in step 236 (step 238). The data output unit 62 records an image on the thermal paper for each color in the switchback format shown in each drawing of FIG. 6, and outputs a color print proof image of the image document. Next, it is determined whether or not there is an input from the operator to the editing apparatus 10 (step 240). If there is no input (step 240 negative determination), the process waits without performing the next process. Here, the operator determines whether or not the color print proof image is output with an appropriate color density, and
The next process based on the determination result is instructed using the keyboard or mouse 36 of FIG.

In the above determination, the color print proof image is transferred from the thermal paper to plain paper used for actual color printing, and the operator determines the output density based on the image transferred on the plain paper. As shown in FIG. 16, this transfer is performed through a process of temporarily transferring a color print proof image from heat-sensitive paper to translucent laminated paper, and transferring the image transferred to the laminated paper to plain paper.

The transfer to plain paper is not limited to the method shown in FIG. 16, but the thermal paper 116 shown in FIG. To create a four-color back image, and thermally transfer the four-color back image to plain paper. Also, images of each color of K, C, M, and Y are printed one by one on a transparent film, and a four-color back image is created by transferring the image of the four-color transparent film one by one on laminated paper. A method of thermally transferring the four-color back image to plain paper can be adopted. The reason why the color print proof image is transferred to plain paper used for actual printing is that the thermal paper is coated with a heat-sensitive material, and the plain paper is also glossy or matte. This is to ensure fairness of the color proofing because the visual impression of the operator is different.

Next, as shown in FIG. 8, when there is an input from the operator (Yes at step 240), the editing device 10 analyzes the input and determines whether or not the editing is requested. Is determined (step 242).

If it is determined that color proofing is requested (Yes at step 242), the standard color conversion data 68 of the color printer 12 is changed (step 244). Then, the designated print condition correction data, the changed standard color conversion data, and the printer condition correction data obtained by the calibration adjustment in FIG. 7 are combined to create a new combined LUT 60 (step S1). 246), returning to step 232 to repeat the same processing. On the other hand, if it is determined that color proofing has not been requested (step 242, negative determination), the process ends.

In the case of producing a color print (step 23)
0 negative determination), the color printing machine 20 (see FIG. 1) combines the designated printing condition correction data, the standard color conversion data obtained by calibration, and the printer condition correction data obtained by calibration adjustment. , Create a composite LUT (step 248). It should be noted that the composite LUT may be transferred from the composite LUT created on the color printer 12 to the color printer 20 via the editing machine 10 by the calibration.

Next, the editing device 10 inputs the dot area ratio data Y, M, C, K of the color print 26 to the color printer 20. This data is obtained from the color scanner 50.

In the color printer 20, the input halftone dot area ratio data is color-corrected by the composite LUT obtained in step 248, and this image is output on a plate making film (step 252).

Then, the plate making film is subjected to plate printing by a plate printing apparatus to produce a color print finally obtained (step 254), and the process is terminated.

As described above, since the color calibration is performed after the calibration adjustment is performed using the small versatile thermal printer, the efficiency of the color calibration can be improved.

(Second Embodiment) Next, a second embodiment will be described below with reference to the block diagram of FIG. Note that the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 9, in the color printer 12 according to the second embodiment, an input terminal 53 of a first output path 55 is provided without providing a data switching unit unlike the first embodiment. And the input end 13 of the second output path 57 are provided. The editing device 10 is provided with an output end 11 for outputting test chart data and an output end 51 for outputting image data for a color print proof image. The output end 11 is connected to the input end 13. The output terminals 51 are connected to the input terminals 53, respectively.

With this connection, the image data for the color print proof image output from the editing device 10 passes through the first output path 55, is color-corrected by the color correction calculation section 58, and is directly output to the data output section. 62.
The test chart data output by the editing device 10 is
Are output directly from the data output unit 62 without being subjected to color correction by the color correction calculation unit 58. Note that even when the editing device 10 has one output terminal, the operator may connect the output terminal to either the input terminal 11 or the input terminal 53 according to the data to be output.

The flow of the calibration processing, the color print image creation processing, and the like are the same as those in the first embodiment, and a description thereof will be omitted.

As described above, in the second embodiment, the first
The switching between the output path and the second output path is performed by switching the connection with a device external to the color printer, so that it is not necessary to provide a means for switching the output path in the color printer, and the device can be downsized and simplified. can do.

The above is the calibration adjustment method for the color printer 12 according to the embodiment of the present invention, but is not limited to the above example. For example, although the synthesis LUT 60 for color correction is in a table format, the neural network 130 may be used for color correction instead of a table, for example.

As shown in FIG. 10, the neural network 130 has an input layer to which each data of Y, M, C, and K is input, one or more intermediate layers, and Y ′,
It has three or more output layers for outputting M ′, C ′, and K ′ data, and the neuron elements 132 of each layer are connected by synaptic connections 134. When this neural network is used for color correction, a so-called back-propagation learning method is used in step 218 in FIG. Retrain at.

In the color printer 12, color correction is performed on the dot area ratio data Y, M, C, and K.
The present invention can be applied to a case where color correction is performed on R, G, and B data. In this case, the composite LUT 60 is a three-dimensional table.

Also, the composite LUT 60 is created by synthesizing three types of correction data, ie, print condition correction data, standard color conversion data, and printer condition correction data. The present invention can also be applied to the case where the correction data of (1) is used.

[0102]

As described above, according to the first aspect of the present invention, while adjusting the printer condition correction data, the synthesis table is not created, and the test image data is prepared using only the printer condition correction data. Is corrected, and the color printer outputs the corrected test image without performing the conversion by the synthesis table. Therefore, the conventional calibration adjustment method in which the synthesis table is created for each adjustment of the printer condition is performed. In comparison, an advantage is obtained in that the time for calibration adjustment can be greatly reduced while maintaining the advantages of saving memory and improving the color conversion speed by the one-stage synthesis table.

According to the second aspect of the present invention, the first output path through which the test image data corrected in the correction step is output without color correction by the combination table, and the input image data is converted by the combination table Since the second output path for color-corrected output is provided in the color printer, a further effect is obtained that the calibration adjustment can be easily performed without reducing the versatility of the color printer.

According to the third aspect of the invention, since the test image data is corrected by the editing device connected to the color printer, the color printer can be simplified and downsized. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a system configuration for creating a color print proof image and a color print.

FIG. 2 is a circuit diagram of an editing device functioning as a higher-level device of the color printer according to the embodiment of the present invention.

FIG. 3 is a block diagram of the color printer according to the first embodiment of the present invention.

FIG. 4 shows a color printer according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a thermal printer as an example.

5A and 5B are partial views of the thermal printer according to the embodiment of the present invention, in which FIG. 5A is a perspective view of an ink sheet supply / recovery system and a thermal paper transport system in the thermal printer, and FIG.
FIG. 4 is a diagram showing each ink area of an ink sheet.

6A and 6B are diagrams showing a thermal paper transport path of the thermal printer according to the embodiment of the present invention, in which FIG. 6A is at the time of drawing out from a paper tray, FIG. FIG. 7D is a diagram illustrating a transport path when the switchback method is executed, FIG. 7D illustrates a sheet discharging path, and FIG.

FIG. 7 is a flowchart illustrating a flow of calibration adjustment of the color printer according to the embodiment of the present invention.

FIG. 8 is a flowchart illustrating a flow of a color proofing process for creating a color print proof image and a process of creating a color print by a color printing machine.

FIG. 9 is a block diagram of a color printer according to a second embodiment of the present invention.

FIG. 10 is a configuration diagram of a neural network used in place of a synthesis LUT for color correction of the color printer according to the embodiment of the present invention.

11A and 11B are diagrams illustrating a color correction table in a conventional calibration adjustment, in which FIG. 11A illustrates a case where a color correction table and a calibration table are divided into two stages, and FIG. FIG. 9 is a table diagram in a case where a calibration table and a calibration table are combined into a single-stage table.

FIG. 12 is a flowchart showing a flow of a conventional calibration adjustment.

13A and 13B are diagrams for explaining the necessity of correction using printer condition correction data, wherein FIG. 13A is a graph showing a relationship between a printer signal and an output density, and FIG. 6 is a graph showing a relationship with the printer signal of FIG.

FIG. 14 is a diagram showing a format of a test chart or a reference chart for comparison printed at the time of calibration adjustment.

FIG. 15 is a diagram illustrating an image document read by a color scanner.

FIG. 16 is a diagram illustrating a process when a color print proof image of a thermal paper is transferred to plain paper.

[Description of Signs] 10 Editing Device 12 Color Printer 44 Printer Condition Correction Data 52 Data Switching Unit 58 Color Correction Operation Unit 60 Synthetic LUT 62 Data Output Unit 64 Synthesis Operation Unit 68 Standard Color Conversion Data 70 Printer Condition Correction Data

Claims (3)

[Claims] 1. A one-stage combination table obtained by combining at least two types of correction data of color correction data for color calibration and printer condition correction data for correcting printer conditions. A calibration method for a color printer that performs data conversion using the correction table, wherein a correction step of correcting test image data only with the printer condition correction data, and the test image data corrected in the correction step is performed using the synthesis table. A color printer calibration adjustment method, comprising: an output step of outputting from a color printer without performing color correction. 2. The color printer according to claim 1, further comprising: a first output path for performing color correction on the input image data using the synthesis table and outputting the output image data; and outputting the input image data without performing color correction using the synthesis table. And a second output path for outputting the test image data corrected in the correction step through the second output path. 3. The calibration adjustment method for a color printer according to claim 1, wherein the correction step is performed by an editing device connected to the color printer.