JPH07288704A - Picture processor, picture processing method and color data communication method - Google Patents

Abstract

PURPOSE:To measure the color reproduction characteristics of a printer at any time as needed and to change a color correction processing corresponding to the characteristics of the printer. CONSTITUTION:A printer driver 201 and a communication part 202 are provided on the side of a host computer 207 and a printing execution part 204, a color measurement device 205, a printing color measurement control part 206 and the communication part 203 are provided on the side of the printer 208. The printer 208 performs printing with the binarized data {(c,) (y,) (m) and (k)} of cyan, magenta, yellow and black as input values. Thus, the printer driver 201 is in charge of a conversion processing from RGB multilevel data to (c,) (m,) (y) and (k) binary data and the color correction processing is included in the process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, an image processing method and a color data communication method suitable for performing color image printing.

[0002]

2. Description of the Related Art A conventional color reproduction method in the case where data specifying a color is supplied from a host computer to a printer and the color is reproduced more faithfully according to the data will be described below.

The color data (image data) on the host computer is composed of RGB multi-valued data designating the three primary colors, and is usually a standard color system (CIE RG).
B color system, NTSC RGB color system, etc.). Then, in order to faithfully reproduce the color of the original color data by color printing by the printer, the tristimulus values of the printed matter output by the printer must have the same values as the tristimulus values of the original color data. .

For this purpose, the original color data, namely R
In the process of converting the GB data into data for driving the printer (data for controlling the output amount of ink, toner, etc.), it is necessary to perform an appropriate color correction process. The process of converting the data and the conventional method for the color correction process will be described below with reference to FIG.

As shown in FIG. 1, (Process 1) 101 to (Process 3) 103, and (Process 4) 10 as required.
Data conversion is performed via 4. Each of these processes will be described in order.

(Processing 1): Multivalued luminance data (R,
G, B) is converted into multi-valued density data (C, M, Y) of ink, toner, etc., which have a complementary color relationship with this. The following (formula 1) is usually used for this conversion.

[0007]

[Number 1] luminance-density conversion formula _{C = C c × logR M =} C m × logG Y = C y × logB (C c, C m, C y is a constant) ... (Equation 1) (process 2): Ink Ya In order to correct the absorption characteristic of toner and the like, that is, the output characteristic of the printer, as shown in (Equation 2), a primary matrix operation is performed on the (C, M, Y) data and converted into (C′M′Y ′). To do. This method is well known as a masking process. The matrix m _{i, j} used here (Formula 2) is determined so as to optimize the color reproducibility of the printer, and this calculation method is also known.

[0008]

## EQU2 ## C '= m ₁₁ C + m ₁₂ M + m ₁₃ Y M' = m ₂₁ C + m ₂₂ M + m ₂₃ Y Y '= m ₃₁ C + m ₃₂ M + m ₃₃ Y (Equation 2) (Processing 3): A black component from the above CMY Generation (black generation) and subtraction (UCR) of each CMY component corresponding to this black component are performed to obtain C ″ M ″ Y ″ K ″. When the print engine of the printer has a function of outputting multi-valued data, this C "M" Y "K" becomes the data for driving the print engine of the printer, and in the printer, ink, toner, etc. are printed according to this data. The amount of output is controlled. Further, the methods of black generation and UCR (undercolor removal) are known.

(Process 4): When the print engine of the printer can output only binary data, halftone processing for expressing multivalued color data by binary dots is performed.
By this halftone process, binarized data cmyk is generated. Methods such as a dither method and an error diffusion method are well known for this halftone processing.

There is also a method of using color correction by a lookup table in the above (Processing 2) part.

In the conventional method described above, focusing on which of the printer and the host computer takes charge of the color correction processing of (Processing 2), it is classified into the following two types.

(Method A) When color correction is performed in the image processing unit inside the printer.

(Method B) When color correction is performed by software on the host computer side.

First, the above (Method A) will be described. When the printer prints using CMYK multi-valued data as input values, that is, on the printer side (process 2) in FIG.
In the case of performing (1) to (Process 4), the color correction process is borne by the image processing unit inside the printer. It is also conceivable that the printer performs printing by using RGB multi-valued data as an input value, and the printer performs (Process 1) to (Process 4) in FIG.

Next, the above (Method B) will be described. In a computer system, drawing data created by an application program is usually output to a printer by basic software called a printer driver. At this time, the printer driver performs data conversion from (Processing 1) to (Processing 4) according to the characteristics of the printer, and the printer driver bears the color correction processing.

[0016]

When the color reproduction is performed by the conventional method, the following points become problems.

In the case of (method A) described in the section of the prior art,
The correction method must be changed for each printer characteristic. That is, a masking coefficient, a look-up table, and the like must be created according to the color output characteristics of the printer, and incorporated into the image processing unit of each printer as data. Therefore, every time a printer having different characteristics is developed, it is necessary to change the masking coefficient, the look-up table, and the like to newly design the image processing unit of the printer, and it costs much to develop the image processing unit of the printer. In addition, if there are variations in the color output characteristics after the printer is manufactured, it is not possible to deal with this, and it is also not possible to deal with the case where the color of the paper used for printing changes.

In the case of (method B) described in the section of the prior art, as in the case of (method A) above, a masking coefficient, a look-up table, etc. are created in accordance with the color output characteristics of the printer, and the printer is Must be included in the driver program. Therefore, on the host computer side, printer drivers corresponding to each printer must be prepared for each type of printer.

The problems in the case of realizing the color reproduction by the method according to the prior art are summarized as follows.

(Problem): When the printer or the printer driver is provided with a mechanism for fixing the data used for the color correction and always performing the color correction in the same method, fluctuations in the output characteristics of the printer and the color of the paper Can not cope with the fluctuation of.

Therefore, the first object of the present invention is not only to solve the problems of the prior art to realize more faithful color reproduction of a printer, but also to improve the characteristics of the printer over time. An object is to provide a color processing device that can deal with the problem.

A second object of the present invention is to define a protocol between a printer and a host computer at the time of a color correction process changing operation, so that even for a plurality of printers having different color output characteristics according to this protocol. It is an object of the present invention to provide a color data communication method capable of realizing color reproduction with a single printer driver complying with a protocol.

[0023]

In order to achieve the first object, a color processing apparatus according to the present invention includes a transmitting means for transmitting patch data to an output device and an output device based on the patch data. It is provided with receiving means for receiving the data obtained by reading the output data, and generating means for generating color correction data in consideration of the output characteristics of the output device from the patch data and the data received by the receiving means. is there. Further, storage means for storing the color correction data generated by the generating means, input means for inputting the original image data, and the stored color correction data for the original image data input by the input means It is preferable to include color correction means for performing color correction using the color correction means and second transmission means for transmitting the image data color-corrected by the color correction means to the output device.

Further, the color processing apparatus according to the present invention is the first communication for transmitting the color measurement data obtained by the color measurement means and the color measurement means for measuring the color of the recording material on which the image is to be formed. Second means for exchanging data and a procedure control signal between the means and the first communication procedure according to a predetermined protocol.
Communication means and color correction means for inputting the colorimetric data via the second communication means and determining color data based on the colorimetric data. Means for transmitting to the first communication means.
Here, it is preferable that the color measurement unit and the first communication unit are provided on the printer side, and the second communication unit and the color correction unit are provided on the host computer side.

In the color processing method according to the present invention, the patch data is transmitted to the output device, the data read by the output device based on the patch data is received, and the patch data and the received data are received. To generate color correction data in consideration of the output characteristics of the output device. Further, the generated color correction data is stored, color correction is performed on the input original image data using the stored color correction data, and the color corrected image data is transmitted to the output device. Is preferred.

In order to achieve the above-mentioned second object, the color data communication method according to the present invention measures the color of the recording material placed on the printer side, and measures the color measurement data of the recording material. Is supplied to the external device according to the first procedure, and the color data corrected based on the colorimetric data is supplied from the external device to the printer according to the second procedure.

[0027]

According to the present invention, not only the problems of the prior art can be solved and more faithful color reproduction of the printer can be realized, but also the secular change of the characteristics of the printer can be coped with. (Corresponding to items 1 to 6).

Further, according to another aspect of the present invention, by defining a protocol between the printer and the host computer during the color correction process changing operation, even for a plurality of printers having different color output characteristics according to this protocol. The color reproduction corresponding to one printer driver according to this protocol can be realized (corresponding to claim 7).

More specifically, by implementing the present invention, the printer driver is provided with a changeable color correction function, while the printer is provided with a color measurement function. Can be solved.

[0030]

EXAMPLES First, the outline of the examples described in detail below will be described.

In constructing a system for printing color images, a printer having means (P) shown below,
A host computer having the means (S) shown below is provided, and the protocol (PS) shown below is defined between the printer and the host computer.

(P): Printer having the following two means: Means for measuring the color of printed matter or paper. Means for transmitting color measurement data to the host computer (S): Host computer having means-For the purpose of optimizing color reproduction, "color information A of the image data to be output" and "information about the difference between the color data input to the printer and the color data actually output. Means for determining color data to be input to the printer based on "B" -means for receiving colorimetric data from the printer-means for updating information B based on the colorimetric data obtained from the printer (PS): printer The following two rules are defined between the host computer and the host computer.

A communication procedure for the printer and the host computer to perform a special cooperative operation (coordination operation) of changing the color correction data. The color data sample sent from the host computer to the printer and the measurement data sent from the printer to the software. Data Format of Color Data In one embodiment to which the present invention is applied, (1) as basic software on the host computer side, the following (1.1) to (1.
It has basic software that realizes the means of 5), and (2)
The printer has the following means (2.1) and (2.2), and (3) the following (3.1) and (3.2) defined between the basic software and the printer. It has a protocol shown in.

(1.1) means for transferring data to a printer, (1.2) means for calculating color correction data used for color correction calculation based on patch data and colorimetric data, (1.
3) Means for receiving colorimetric data from the printer, (1.
4) means for performing color correction processing on the color data to be printed to create new color data, and (1.5) means for accepting an instruction to activate normal printing processing and color correction processing change processing from other software. .

(2.1) Means for measuring the color of printed matter, (2.
2) A means for transferring colorimetric data to a host computer.

(3.1) A communication protocol for the host computer to control the printer during normal printing,
(3.2) A communication protocol for the host computer and the printer to perform a series of color correction process changing operations in order to change the color correction coefficient.

With the above arrangement, color printing can be realized by correcting the color reproduction characteristics of the printer and faithfully reproducing the color data on the host computer. When the color reproduction characteristics of the printer change, the basic software on the host computer and the printer are caused to perform a special operation, and the color correction processing of the basic software is changed. This makes it possible to perform color correction that matches the new color reproduction characteristics.
Color reproducibility can be secured.

An embodiment of the present invention will be described in detail below with reference to FIGS.

In this embodiment, as shown in FIG. 2, a printer driver 201 and a communication unit 202 are provided on the host computer 207 side, a print execution unit 204, a color measurement device 205, and a print color measurement control unit on the printer side. 206 and the communication unit 203
Take the configuration that has. In this embodiment, the printer prints using binarized cyan, magenta, yellow, and black data (c, m, y, k in FIG. 1) as input values. Therefore, the printer driver bears the conversion from RGB multi-valued data to c, m, y, k binary data (process 1 to process 4 in FIG. 1), and includes a color correction process in this process.

FIG. 3 is a block diagram showing processing functions executed by the printer driver 201. The processing function shown in FIG.
Is executed by the basic software for causing the printer 208 to perform printing. Generally, such basic software is called a printer driver. The operation of this printer driver will be described below.

During normal printing, the image data (RGB in FIG. 3) 301, 302, 3 transferred from the application program via the communication unit 202 of the host computer.
The processing of 03 and 304 is performed to generate print data, and this data is transferred to the printer. In the processing performed at this time, the color correction processing 302 is performed, and in this embodiment, the masking method is used as the color correction processing.

During the color measurement operation, print data of patch data is sent to the printer and color measurement data is received from the printer. Then, the color correction data is calculated based on the color measurement data, and the color correction data, that is, the masking coefficient 30 is calculated.
Update 6

FIG. 4 shows the detailed construction of the print execution unit 204. The operation of the print execution unit shown in this figure is as follows.

Input stage paper feed mechanism 404 during printing
Sends the paper to the print engine 403, and the print engine 4
03 prints according to the print data in the print data buffer 406. The print engine may be an inkjet / heat-sensitive line printer or a page printer such as an electrophotographic printer, and the mechanism by which these devices perform printing is known. The output stage paper feed mechanism 405 has a mechanism that enables two types of conveyance methods, that is, continuous movement of the paper and intermittent movement of the paper. Switching between these two operations is performed by the print color measurement control unit 408. Done by signal.

FIG. 5 shows the structure of the color measuring device 205. The colorimetric apparatus shown in this figure has a function for measuring the tristimulus values of a printed matter, and the operating principle thereof is already known, so it will be briefly described. The colorimetric apparatus includes a measurement control unit 502, a white light source 505, three sets of color filters 506, an optical sensor 507,
The amplification circuit 508 and the correction circuit 509 are used to measure the tristimulus value, which is the spectral reflectance of the object, according to the following (Equation 3).

[0046]

R = Kr∫S (λ) F (λ) Tr (λ) dλ G = Kg∫S (λ) F (λ) Tg (λ) dλ B = Kb∫S (λ) F (λ) Tb (λ) dλ (Equation 3) In (Equation 3), λ is the wavelength of light, S (λ) is the spectral energy distribution of the light source, F (λ) is the spectral reflectance of the object, and Tr is
(Λ), Tg (λ), and Tb (λ) are NTSC, respectively.
It represents the color matching function of the RGB color system. Also, Kr, Kg, K
b represents a standardization constant.

The colorimetric device in this embodiment outputs tristimulus value data according to the NTSC RGB color system as tristimulus values. In order to obtain the tristimulus values defined by the NTSC RGB color system, the transmittance of the color filter 506 placed in front of the optical sensor and the wavelength dependence of the sensitivity of the optical sensor 507 can be calculated using the NTSC-RGB color system. The color matching function of the system may be approximated to one value and the outputs from the three photosensors may be corrected by the correction circuit 509.

The white light source 505 has an NTSC R
The characteristics of the C light source specified by the GB color system are required,
The difference between the white light source actually used and the C light source is the color filter,
It can be easily corrected by the correction circuit.

The timing of the color measurement operation of this apparatus is controlled by the print color measurement control section. This apparatus causes the white light source 505 to emit light when receiving a color measurement trigger signal from the print color measurement control unit.
The color measurement data obtained from the color measurement unit 504 is sent back to the print color measurement control unit.

In this embodiment, as a color reproduction standard,
Although the NTSC RGB color system is used, it goes without saying that any other color system can be used.

The print color measurement control unit 206, the communication unit 203,
The interface between the print executing unit 204 and the color measuring device 205 is as shown in FIG. This print color measurement control unit 2
Reference numeral 06 analyzes data sent from the host computer via the communication unit 203 and controls the operation of the printer. During normal printing, print data from the host computer is sent to the print execution unit 204. When a command such as a color measurement request is received from the host computer, an operation switching signal is sent to the print execution unit so that the color measurement operation can be performed. During the color measurement operation, the print data of the patch data is sent to the print execution unit and the color measurement trigger signal is sent to the color measurement device to obtain the color measurement data from the color measurement device. The obtained color measurement data is sent back to the host computer through the communication unit.

Further, the host computer 207 and the printer 208 are provided with respective communication units 202 and 203 to realize data transfer between the host computer 207 and the printer 208. The communication method may be serial data transfer such as RS232C, or parallel data transfer such as Centronics or SCSI.

Next, the overall operation of this embodiment will be described.

The printer driver 201 and the printer 208 on the side of the host computer have an operation mode for performing normal printing and two operation modes for changing color correction data. Hereinafter, these two modes are referred to as a normal print mode and a color correction data change mode, respectively.

(Operation in Normal Print Mode) In the normal print mode, the following operation is performed.

When the application program sends the print request and the image data to be printed to the printer driver,
The printer driver generates print data through a series of processes shown in FIG. This series of processes will be described in detail.

(Process 1) 301: Using (Equation 1),
The brightness data (RGB) is converted into density data (CMY) of ink, toner, etc., which have a complementary color relationship with the brightness data.

(Processing 2) 302: In order to correct the absorption characteristics of ink and toner, that is, the output characteristics of the printer, the (CMY) data is subjected to the primary masking processing (Equation 2).
Is converted to (C ′, M ′, Y ′). The masking coefficient used here becomes the data updated in the color correction data change mode.

(Processing 3) 303: The black component is generated from the above C'M'Y '(black generation) and each CMY component corresponding to this black component is subtracted (UCR) to obtain C "M".
Y "K".

(Processing 4) 304: Multivalued color data
Performs halftone processing for expressing with binary dots.

When the printer drive data is generated by the above processing, the printer driver transfers this data to the printer.

When the printer receives the printer drive data from the printer driver, the print colorimetric control unit of the printer sends this data to the print executing unit to perform printing.

(Operation in Color Correction Data Change Mode) FIG. 6 shows the processing procedure and operation in the color correction data change operation mode.

When the color correction data change request 601 is generated in the normal print mode, the printer driver and the printer enter the color correction data change operation mode and execute the procedure shown in FIG. The procedure and operation will be described below.

The printer driver issues a color correction data change processing start command 602 to the printer in order to start the color correction data change processing, and has a response 604 indicating completion of preparation from the printer.

The printer receives the change processing start command and prepares for the next color measurement so that the color of the printed matter can be measured.

(Preparation for color measurement) First, as shown in FIG. 4, the print color measurement control unit 206 of the printer sends an operation switching signal to the print execution unit 204. When the print execution unit receives the color measurement operation transition signal, the print engine control unit 402 of the print execution unit
Switches the control mechanism so that the operation of the output stage paper feeding mechanism is intermittently moved. This switching can be easily realized as follows if the control of the paper feeding mechanism by the print engine control unit is performed by the microprocessor.

First, a subroutine (software) describing two operations of continuous movement and intermittent movement is prepared, and a flag for deciding which subroutine is executed is prepared, and the operation is switched from the print colorimetry control section. Rewrite the flag according to the signal. Then, when executing normal printing or patch data printing, this flag is determined,
Either one may be selectively executed.

When the above preparations are completed, the printer sends a preparation completion response 604 to the host computer, and the arrival of patch data.

When the printer driver receives a response indicating completion of preparation from the printer, as shown in FIG. 3, the patch data 308 has a luminance density conversion 301 and a black generation UCR 30.
3. The process of binarization 304 is performed to generate print data of patch data. At this time, the masking process 302 is not performed. Alternatively, the print data 309 of the patch data may be generated in advance and sent directly to the printer. When the print data of the patch data is sent to the printer, the printer driver has the arrival of the color measurement data. A broken line in FIG. 3 is a data path when print data of patch data is generated.

The number of patch data may be several. The color data of the patch portion is data NTSCRGB color system, (R ₁ in this order from the top of the sheet as shown in FIG. 7,
G ₂ , B ₃ ), (R ₂ , G ₂ , B ₂ ), (R ₃ , G ₃ ,
B ₃₎ ... are arranged with.

This data group is expressed as (R _i , G _i , B _i ) below.
Is written. i means an index for distinguishing patch data.

When the printer receives the print data of the patch data, it carries out the following color measurement operation.

Next, the color measurement operation will be described with reference to FIG.

When the printer receives the print data of the patch data, the print color measurement control unit 206 sends the print data of the patch data to the print execution unit 204, the first patch data is printed, and the color measurement position of the color measurement device 205 is printed. Wait to come to.

When the print execution unit 204 finishes printing the patch data and sets the paper so that the first patch data comes to the color measurement position, this print execution unit executes the print color measurement control unit 206.
Send a patch data set completion signal to. Upon receiving the patch data set completion signal, the print color measurement control unit 206 sends a color measurement trigger signal to the color measurement device 205. When the color measurement device 205 executes color measurement and obtains color measurement data, the print color measurement control unit 2
06 stores this one colorimetric data in the buffer 406.

The print execution unit 204 outputs a patch data set completion signal, then waits for a sufficient time to perform color measurement, sets the paper so that the next patch data will come to the color measurement position, and sets the patch data set again. Send a completion signal.

When the above operation is repeated and the color measurement of all patch data is completed, the print color measurement control unit 206 outputs all the color measurement data stored in the buffer 406 to the printer driver 2
Send to 01. In the above color measurement operation, the output stage paper feed mechanism 40 sets the patch data at the color measurement position.
It is realized by intermittent paper movement of 5. Further, the print color measurement control unit 206 may send one color measurement data to the printer driver while waiting for the patch data set completion signal from the print execution unit 204, without storing the color measurement data. When the above is completed, the printer transfers the colorimetric data to the host computer.

Here, the colorimetric data group is represented by (R ′ _i ,
_G'i , _B'i ).

When the printer driver 201 receives all the colorimetric data from the printer, the patch data group (R _i , G _i , B _i ) 3 sent to the printer is sent as shown in FIG.
08, and the color measurement data group (R '
_{Based on i} , G ′ _i , B ′ _i ) 307, the masking coefficient is calculated according to the following calculation process.

(Calculation Process) In this embodiment, a primary masking process is used for the color correction method, and a primary masking coefficient is used for the color correction data. The principle of the first-order masking process is that the color reproduction characteristics of the printer are linearly transformed, that is, approximated by a first-order matrix, the inverse matrix is obtained, and the data on which the inverse matrix is applied is input to the printer. This is a method of correcting the characteristics. However, in the actual calculation procedure, the inverse characteristic of the color reproduction characteristic of the printer, that is, the inverse matrix is directly obtained from the colorimetric data, and the inverse matrix is not calculated. The calculation procedure will be described below with reference to FIG.

A primary matrix representing the inverse characteristic of the color reproduction characteristic of the printer is obtained. This calculation is performed by the color correction data calculation unit 305. Since the masking calculation is performed on the density data CMY, it is necessary to represent the inverse characteristic of the color reproduction characteristic of the printer in the CMY space.

Therefore, first, as shown in FIG. 8, the color data (R _i , G _i , B _i ) input to the printer and the color data (R ′ _i , G ′ _i , B ′) output from the printer. _i )
According to (Equation 1), (C input _i , M input _i , Y input
_i ) and (C measurement _i , M measurement _i , Y measurement _i ). Then, the relationship of the following (formula 4) is processed between the data.

[0084]

[Equation 4] C input _i = m ₁₁ C measurement _i + m ₁₂ M measurement _i + m ₁₃ Y measurement _i M input _i = m ₂₁ C measurement _i + m ₂₂ M measurement _i + m ₂₃ Y measurement _i Y input _i = m ₃₁ C measurement _i + m ₃₂ M measurement _i + m ₃₃ Y measurement _i (Equation 4) m _{ij in} this (Equation 4) represents the inverse characteristic of the color reproduction characteristic of the printer. However, since the linear matrix used here is only an approximation, there is no _mij that satisfies (Equation 4) for all data. Therefore, the deviation D between the relationship determined by _mij and the relationship that the actual data follows is defined by the following (Equation 5), and the optimum m that minimizes this deviation is defined.
_The printer characteristics are approximated by finding _ij .

[0085]

[Equation 5]

This calculation method is well known as the least squares method, and the condition for determining the optimum m _ij is the following (formula 6), and the 3 × 3 equation in the following (formula 7) is derived from this condition. Get burned.

[0087]

[Equation 6]

[0088]

[Equation 7]

Above

[0090]

[Outer 1]

Further, X _pi and Y _{pi in} (Equation 8) and (Equation 9) are defined by the following (Equation 10).

[0092]

[Equation 8]

[0093]

[Equation 9]

[0094]

[Formula 10] Definition of X _pi Definition of Y _pi X _1i = C measurement _i Y _1i = C input _i X _2i = M measurement _i Y _2i = M input _i X _3i = Y measurement _i Y _3i = Y input _i p = 1,2,3 ... (equation 10) here, since (equation 7) are simultaneous equations defining uniquely the m _ij, m _ij, that is, the masking coefficient is determined by solving this. Further, N in (Equation 8) and (Equation 9) represents the total number of patch data.

Upon completion of the above calculation processing, as shown in FIG. 6, the printer driver should start the normal printing operation.
A normal print operation shift command 609 is sent to the printer, and the printer waits for a response 609 from the printer indicating that the normal print operation shift is completed.

Upon receipt of the normal print operation shift command, the printer undoes the change in the print execution unit made in the colorimetric preparation and returns to the printer driver a response 6 to the normal print operation shift completion.
Returns 09.

When the printer driver receives from the printer a response indicating that the normal print operation has been completed, the printer driver enters the normal print mode and waits for a print request.

In the above embodiment, the color correction processing of the printer driver may be changed to the processing using the LUT (lookup table) and the masking coefficient calculation processing portion may be changed to the LUT correction processing. Is.

Thus, according to the above embodiment, the color reproduction characteristics of the printer can be measured at any time and the color correction processing can be changed according to the characteristics of the printer.

[0100]

As described above, according to the present invention, not only the problems of the prior art can be solved to realize more faithful color reproduction of a printer, but also the characteristics of the printer can be prevented from aging. However, it is possible (corresponding to claims 1 to 6).

Further, according to another aspect of the present invention, by defining a protocol between the printer and the host computer at the time of the color correction process changing operation, even for a plurality of printers having different color output characteristics according to this protocol. The color reproduction corresponding to one printer driver according to this protocol can be realized (corresponding to claim 7).

Further, it is possible to generate color correction data in consideration of the output characteristics of the output device from the patch data and the data received by the receiving means (corresponding to claims 1 and 5).

Further, the original image data input by the input means is color-corrected using the stored color correction data, and the color-corrected image data can be transmitted to the output device. It corresponds to 2,6).

[0104]

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a general process of generating print data from image data.

FIG. 2 is a block diagram showing the overall configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing functions of a printer driver.

FIG. 4 is a diagram illustrating a configuration of a print execution unit and an interface between a print color measurement control unit and another block.

FIG. 5 is a diagram illustrating a structure of a color measuring device.

FIG. 6 is a diagram illustrating a sequence of a system when a color correction data changing operation is performed.

FIG. 7 is a diagram showing a color data arrangement of patch data.

FIG. 8 is a diagram illustrating correspondence between luminance data and density data at a stage of calculating a masking coefficient.

[Explanation of symbols]

 101 Luminance Density Conversion Processing Block 102 Color Correction Processing Block 103 Black Generation / UCR Processing Block 201 Printer Driver of Host Computer 202 Communication Unit of Host Computer 203 Communication Unit of Printer 204 Print Execution Unit of Printer 205 Color Measuring Device of Printer 206 Printer Print color measurement control unit 207 Host computer 208 Printer 301 Luminance density conversion unit 302 Color correction unit 303 Black generation / UCR unit 304 Binarization unit 305 Masking coefficient calculation unit 306 Masking coefficient 307 Color measurement data 308 Patch data 309 Patch data printing Data 402 Print engine control unit 403 Print engine 404 Input stage paper feed mechanism 405 Output stage paper feed mechanism 406 Print data buffer 502 Measurement control unit 503 Light emitting unit 504 Measurement Color part 505 White light source 506 Color filter 507 Optical sensor 508 Amplification circuit 509 Correction circuit 510 Irradiated light 511 Reflected light 512 Printed matter

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Claims (7)

[Claims] 1. A transmitting unit for transmitting patch data to an output device, a receiving unit for receiving data read by the output device based on the patch data, and a receiving unit for receiving the patch data and the receiving unit. An image processing apparatus comprising: a generation unit configured to generate color correction data in consideration of an output characteristic of the output apparatus from the generated data. 2. A storage unit for storing the color correction data generated by the generation unit, an input unit for inputting document image data, and the stored image data for the document image data input by the input unit. 2. A color correction unit that performs color correction using the color correction data, and a second transmission unit that transmits the image data color-corrected by the color correction unit to the output device. The image processing device according to item 1. 3. A colorimetric device for measuring the color of a recording material on which an image is to be formed, a first communication device for transmitting the colorimetric data obtained by the colorimetric device; Second communication means for exchanging data and procedure control signals with the first communication means, and inputting the colorimetric data via the second communication means,
An image processing apparatus comprising: a color correction unit that determines color data based on the colorimetric data, and transmitting the color data from the second communication unit to the first communication unit. 4. The color measuring means and the first communication means are provided on a printer side, and the second communication means and the color correcting means are provided on a host computer side according to claim 1. Image processing device. 5. Output data of the output device is transmitted from the patch data and the received data by transmitting patch data to the output device, receiving data read by the output device based on the patch data, and receiving the read data. An image processing method characterized by generating color correction data in consideration of the above. 6. The generated color correction data is further stored, color correction is performed on the input original image data using the stored color correction data, and the color corrected image data is stored in the color correction data. The image processing method according to claim 5, wherein the image is transmitted by an output device. 7. A color of a recording material placed on a printer side is measured, color measurement data of the recording material is supplied to an external device according to a first procedure, and correction is performed based on the color measurement data. The second color data
A color data communication method comprising supplying the printer from the external device in accordance with the procedure of 1.