JP2009232001A - Image processing method, image processing program and image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing method of simulating a density value even by a printer having no density sensor by effectively utilizing a simulation result. <P>SOLUTION: In the image processing method, a density correcting process is performed based upon a full simulation result when a first simple simulation result and the full simulation result match each other. Further, when a second simple simulation result and the full simulation result match each other, the full simulation result is corrected and the density correcting process is performed based upon the corrected full simulation result. When the second simple simulation result and the full simulation result do not match each other, or when a user does not satisfy a print result, full simulation is performed again. Based upon a result of the full simulation which is performed again, a density correcting process is carried out. When the user does not satisfy the density correcting process (printing process) based upon the full simulation result, a simulation coefficient is updated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing method for effectively using simulation values for image correction.

  Conventionally, various techniques for correcting image density have been proposed. For example, Patent Document 1 below discloses that a patch image is formed, the density of the formed patch image is measured, and a density correction value is calculated based on the measurement result.

Japanese Patent Laid-Open No. 11-157131

  In Patent Document 1, toner is consumed to form a patch image, and an intermediate transfer member on which the patch image is formed deteriorates. In addition, processing time is also required for patch image formation. Moreover, in the said patent document 1, it is necessary to provide a temperature sensor, a humidity sensor, and a density | concentration sensor. However, even in a printer that includes a temperature sensor and a humidity sensor but does not include a density sensor, a parameter for density correction may be generated by simulation. For example, information on the density change (for example, temperature value, humidity value) is used to simulate how the desired density value changes, and the density correction value is determined based on the result. However, when a simulation (full simulation) is performed for all density values, processing capacity such as a CPU is required, and processing time is also required.

  The present invention has been made to solve the above-described problems, and an image processing method for simulating density values by effectively utilizing already existing simulation values even in a printer that does not include a density sensor. The purpose is to provide.

  The invention according to claim 1, which is an aspect of the present invention, is an image processing method, wherein a first predetermined number of all density values is based on a simulation parameter stored in a first storage means. The simulation value of the density value is calculated, and among the full simulation values of the all density values calculated based on the simulation parameters stored in the first storage unit, the first predetermined number of density values are calculated. The corresponding simulation value is acquired from the second storage means, and the calculated simulation value is compared with the acquired simulation value. If they match, the full simulation value stored in the second storage means is obtained. Based on the simulation parameters stored in the first storage means, if the print data is corrected and does not match, the total density values are corrected. Calculating a simulation value of a second predetermined number of density values greater than the first predetermined number, correcting the full simulation value based on the calculated simulation value, and based on the corrected full simulation value. The printing data is corrected.

  According to the image processing method, the simulation values of the first predetermined number (for example, two) of density values (for example, density values of 10% and 90%) are compared and matched. In this case, the density value correction is performed using the full simulation value. This eliminates the need for a new full simulation. If they do not match, the second predetermined number (for example, four) density values (for example, 20%, 40%, 60%, and 80% density values) of simulation values and full simulation values are obtained. The full simulation value is corrected based on the comparison result, and density correction is performed using the corrected full simulation value. Thereby, the existing full simulation value can be used effectively, and it is not necessary to perform a full simulation. The image processing method can be executed by a computer connected to a printer.

  The invention according to claim 2 which is an aspect of the present invention is the image processing method according to claim 1, wherein the simulation parameter stored in the first storage means is stored when a predetermined condition is satisfied. Based on this, a full simulation value of all concentration values is calculated, and the second storage means is updated based on the calculated full simulation value.

  According to the image processing method, when a predetermined condition is satisfied, a full simulation value of all density values is calculated and newly stored in the second storage unit. Accordingly, a full simulation can be executed and a new full simulation value can be acquired as required by the user. Further, the new full simulation value is used as a comparison target between the simulation value of the first predetermined number of density values and the simulation value of the second predetermined number of density values in the subsequent processing.

  The invention according to claim 3, which is an aspect of the present invention, is the image processing method according to claim 2, wherein the predetermined condition includes a simulation value of the second predetermined number of density values and the acquired simulation value. And / or an input related to a full simulation value calculation instruction for all density values has been received.

  According to the image processing method, a predetermined condition is satisfied (the simulation value of the second predetermined number of density values does not match the acquired simulation value and / or a full simulation of all density values. When an input relating to a value calculation instruction is received), a full simulation value of all density values is calculated and newly stored in the second storage means. Accordingly, a full simulation can be executed and a new full simulation value can be acquired as required by the user. Further, the new full simulation value is used as a comparison target between the simulation value of the first predetermined number of density values and the simulation value of the second predetermined number of density values in the subsequent processing.

  The invention according to Claim 4 which is one aspect of the present invention is the image processing method according to Claims 1 to 3, wherein when a predetermined user input is received, a measurement image is printed and the printed The density of the measurement image is measured, the simulation parameter is calculated based on the measured density, and the first storage unit is updated based on the calculated simulation parameter.

  According to the image processing method, when a predetermined condition is satisfied (a predetermined input is made by the user), a simulation parameter is calculated based on the measurement result of the density value of the patch image, and a new Store in one storage means. As a result, a new simulation parameter can be acquired as required by the user. Further, the density value of the patch image may be measured by an external measuring device. In this case, it is not necessary to provide a density sensor in the printer. Further, the simulation parameter is used in the calculation of the simulation value after the next time.

  The invention according to claim 5, which is an aspect of the present invention, is an image processing program, wherein a first of all density values is stored in a computer based on a simulation parameter stored in a first storage unit. Calculating a simulation value of a predetermined number of density values; out of the full simulation values of all the density values calculated based on the simulation parameters stored in the first storage means, the first predetermined number A step of obtaining a simulation value corresponding to the density value of the second storage means from the second storage means, a step of comparing the calculated simulation value with the obtained simulation value, and if they match, the simulation values are stored in the second storage means. Correcting the print data based on the full simulation value, the first storage means if they do not match Based on the stored simulation parameters, a step of calculating a simulation value of a second predetermined number of density values larger than the first predetermined number among all density values, and based on the calculated simulation value And correcting the full simulation value and correcting the print data based on the corrected full simulation value.

  According to the image processing program, the first predetermined number (for example, two) density values (for example, 10% and 90% density values) of the simulation values are compared with the full simulation values, and they match. In this case, the density value correction is performed using the full simulation value. This eliminates the need for a new full simulation. If they do not match, the simulation values and full simulation values of the second predetermined number (for example, four) of density values (for example, density values of 20%, 40%, 60%, and 80%) are obtained. The full simulation value is corrected based on the comparison result, and density correction is performed using the corrected full simulation value. Thereby, the existing full simulation value can be used effectively, and it is not necessary to perform a full simulation.

  The invention according to claim 6 which is one aspect of the present invention is the image processing program according to claim 5, wherein the simulation parameter stored in the first storage means when the predetermined condition is satisfied. Based on this, the computer is caused to execute a step of calculating a full simulation value of all concentration values and a step of updating the second storage means based on the calculated full simulation value.

  According to the image processing program, when a predetermined condition is satisfied, a full simulation value of all density values is calculated and newly stored in the second storage unit. Thereby, according to a user's need, a full simulation can be performed and a new full simulation value can be acquired. Further, the new full simulation value is used as a comparison target between the simulation value of the first predetermined number of density values and the simulation value of the second predetermined number of density values in the subsequent processing.

  The invention according to claim 7 which is an aspect of the present invention is the image processing program according to claim 6, wherein the predetermined condition includes a simulation value of the second predetermined number of density values and the acquired simulation value. And / or an input related to a full simulation value calculation instruction for all density values has been received.

  According to the image processing program, a predetermined condition is satisfied (the simulation value of the second predetermined number of density values does not match the acquired simulation value and / or a full simulation of all density values When an input relating to a value calculation instruction is received), a full simulation value of all density values is calculated and newly stored in the second storage means. Accordingly, a full simulation can be executed and a new full simulation value can be acquired as required by the user. Further, the new full simulation value is used as a comparison target between the simulation value of the first predetermined number of density values and the simulation value of the second predetermined number of density values in the subsequent image processing.

  The invention according to claim 8 which is one aspect of the present invention is the image processing program according to claims 5 to 7, wherein when a predetermined user input is received, a step of printing an image for measurement, the printing Measuring the density of the measured image, calculating the simulation parameter based on the measured density, and updating the first storage unit based on the calculated simulation parameter. The computer is executed.

  According to the image processing program, when a predetermined condition is satisfied (a predetermined input is made by the user), a simulation parameter is calculated based on the measurement result of the density value of the patch image, and a new Store in one storage means. As a result, a new simulation parameter can be acquired as required by the user. Further, the density value of the patch image may be measured by an external measuring device. In this case, it is not necessary to provide a density sensor in the printer. Further, the simulation parameters are used in the simulation value calculation from the next time.

  The invention according to claim 9 which is an aspect of the present invention is an image processing apparatus, comprising: a first storage unit for storing simulation parameters; and a simulation parameter stored in the first storage unit. Second storage means for storing the full simulation value of all the concentration values calculated in step S1 and a first predetermined number of all concentration values based on the simulation parameters stored in the first storage means. Out of the full simulation values of all the concentration values calculated based on the simulation parameters stored in the first storage means; A first acquisition means for acquiring a simulation value corresponding to one predetermined number of density values from the second storage means; the calculated simulation value; And the comparison means for comparing the calibration value with the means for correcting the print data based on the full simulation value stored in the second storage means when they match. A second simulation for calculating a simulation value of a second predetermined number of density values larger than the first predetermined number among all density values based on the simulation parameters stored in the first storage means If the value does not match the value calculation means, the full simulation value correction means corrects the full simulation value based on the calculated simulation value. If the value calculation means does not match, the value calculation means based on the corrected full simulation value. And print data correction means for correcting the print data.

  According to the image processing apparatus, the simulation values of the first predetermined number (for example, two) of density values (for example, 10% and 90% density values) are compared and matched. In this case, the density value correction is performed using the full simulation value. This eliminates the need for a new full simulation. If they do not match, the second predetermined number (for example, four) density values (for example, 20%, 40%, 60%, and 80% density values) of simulation values and full simulation values are obtained. The full simulation value is corrected based on the comparison result, and density correction is performed using the corrected full simulation value. Thereby, the existing full simulation value can be used effectively, and it is not necessary to perform a full simulation.

  The invention according to claim 10 which is an aspect of the present invention is the image processing apparatus according to claim 9, wherein the simulation parameter stored in the first storage means when the predetermined condition is satisfied. A full simulation value calculating unit that calculates a full simulation value of all concentration values; and an updating unit that updates the second storage unit based on the calculated full simulation value when a predetermined condition is satisfied. It is characterized by having.

  According to the image processing apparatus, when a predetermined condition is satisfied, a full simulation value of all density values is calculated and newly stored in the second storage unit. Accordingly, a full simulation can be executed and a new full simulation value can be acquired as required by the user. Further, the new full simulation value is used as a comparison target between the simulation value of the first predetermined number of density values and the simulation value of the second predetermined number of density values in the subsequent processing.

  The invention according to claim 11 which is an aspect of the present invention is the image processing apparatus according to claim 10, wherein the predetermined condition includes a simulation value of the second predetermined number of density values and the acquired simulation value. And / or an input related to a full simulation value calculation instruction for all density values has been received.

  According to the image processing apparatus, a predetermined condition is satisfied (the simulation value of the second predetermined number of density values does not match the acquired simulation value, and / or a full simulation of all density values. When an input relating to a value calculation instruction is received), a full simulation value of all density values is calculated and newly stored in the second storage means. Accordingly, a full simulation can be executed and a new full simulation value can be acquired as required by the user. Further, the new full simulation value is used as a comparison target between the simulation value of the first predetermined number of density values and the simulation value of the second predetermined number of density values in the subsequent image processing.

  The invention according to Claim 12 which is one aspect of the present invention is the image processing apparatus according to Claims 9 to 11, wherein the image for measurement is printed when a predetermined user input is received. Means for measuring the density of the printed measurement image when a predetermined user input is received, and for the simulation based on the measured density when the predetermined user input is received. Simulating parameter calculating means for calculating parameters, and first storage means updating means for updating the first storage means based on the calculated simulation parameters when a predetermined user input is received. It is characterized by.

  According to the image processing apparatus, when a predetermined condition is satisfied (a predetermined input is made by the user), a simulation parameter is calculated based on the measurement result of the density value of the patch image, and a new Store in one storage means. As a result, a new simulation parameter can be acquired as required by the user. Further, the density value of the patch image may be measured by an external measuring device. In this case, it is not necessary to provide a density sensor in the printer. Further, the simulation parameter is used in the calculation of the simulation value after the next time.

  According to the present invention, based on simulation values of a predetermined number of density values, already existing simulation values can be used effectively.

  A system for realizing an image processing method according to an embodiment of the present invention will be described below. The present invention can also be realized as an image processing program for causing a computer to execute an image processing method described below. Furthermore, the present invention can be realized as an image processing apparatus that executes an image processing method described below.

  FIG. 1 is an example of a system configuration for realizing the image processing method of the present embodiment. As shown in FIG. 1, this system includes a computer 100, a printer 200, and a relay device 300.

The computer 100 and the printer 200 are connected via the relay device 300. The computer 100 and the printer 200 exchange various information. The printer 200 performs printing in response to an instruction from the computer 100. The computer 100 and the printer 200 have identification information (for example, an IP address). The computer 100 executes various programs described later.
Even if the computer 100 and the printer 200 are directly connected using a connection technology such as USB (Universal Serial Bus) without using the relay device 300, various types of information can be similarly transmitted and received.

  In the example shown in FIG. 1, the number of computers 100 is one, but it goes without saying that a configuration including a plurality of computers 100 may be used. In the example illustrated in FIG. 1, the number of printers 200 is one, but a configuration including a plurality of printers 200 may be used.

  Further, the printer 200 may perform some or all of various processes executed by the computer 100. That is, it goes without saying that any computer having a processor that can execute a predetermined program and storage means that can temporarily and permanently store various information can be used as a computer in this embodiment. Moreover, you may comprise so that the one part or all part of the various processes demonstrated below may be performed in the external apparatus connected with the network.

  Of course, this embodiment may be realized by distributed processing by a plurality of computers. Further, a specialized processor and / or memory may be used to execute this embodiment.

The computer 100 basically includes a processor, first storage means, and second storage means. Needless to say, various elements may be added as necessary.
The first storage means is constituted by, for example, a nonvolatile memory. The first storage means stores various programs including programs necessary for realizing the present invention. Various data necessary for realizing the present invention are also stored in the first storage means.
The second storage means is composed of, for example, a volatile memory. The second storage means is loaded with a program or data stored in the first storage means.
The processor executes various processes using data stored in the first storage unit and the second storage unit. It also controls the operation and signal flow of various devices connected to the processor.

  FIG. 2 is a block diagram illustrating an example of the internal configuration of the computer 100. As illustrated in FIG. 2, the computer 100 includes a CPU 11, a ROM 12, a RAM 13, an input / output I / F 14, and a communication I / F 15. The CPU 11 executes various programs (described later) in order to realize the present invention. These programs are stored in the ROM 12. These programs can function as drivers. In executing the program, various data are read / written to / from the RAM 13. Display control of a display (not shown) and transmission / reception of information to / from the input device are performed via the input / output I / F 14. The computer 100 transmits binarized data to the printer 200 via the communication I / F 15. Further, each of the above elements is connected to each other by a signal line. The internal configuration shown in FIG. 2 is merely an example. For example, various programs may be stored in an auxiliary storage unit such as an HDD (not shown) instead of the ROM 12. Needless to say, it is not limited to the one having this internal configuration.

FIG. 3 shows a processing flow in the computer 100 and the printer 200 during printing.
When there is a print request in a predetermined application, the computer 100 acquires print data corresponding to the print request and performs color matching processing on the print data.
The color matching process is performed in order to minimize the difference between the color that can be reproduced by the printer and the color that can be reproduced on the display screen. In the color matching process, the color gamut is replaced by the color profile.

  The computer 100 performs color conversion processing on the pixel density values (RGB) on which color matching processing has been performed. In the color conversion process, the correspondence between the color space on the computer 100 and the color space of the printer 200 is determined using a color profile. Further, for example, RGB values are converted into CMYK values (for example, pixel values of RGB = (255, 0, 0) are converted into CMYK = (0, 220, 133, 0)).

  The computer 100 performs density correction processing on the pixel density values (CMYK) that have undergone color conversion. In the density correction process, density correction parameters are used. Details of the density correction parameter will be described later.

  The density correction parameter is generated by the simulation unit. The simulation unit generates a density correction parameter based on the simulation coefficient and the simulation data. The simulation coefficient is stored in auxiliary storage means (for example, ROM 12) of the computer 100. The simulation coefficient is a numerical value used in a calculation formula for obtaining a concentration value by simulation. In this calculation formula, simulation data (values such as temperature, humidity, and toner usage status in the printer) are used as variables. The simulation coefficient can change the influence of the variable on the calculation result.

  The simulation data is, for example, the temperature, humidity, and toner usage status in the printer 200. The temperature and humidity in the printer 200 are measured by a sensor (not shown). The toner usage status is stored in a predetermined storage unit in the printer 200. The toner usage status is updated every time printing is performed.

The computer 100 performs binarization processing on the pixel density value subjected to density correction. In the binarization process, the gradation value of each color is converted into binary data of area gradation. That is, data is generated in which the dot density is high in the region where the density value is high and the dot density is low in the region where the density value is low. The generated binarized data is transmitted to the printer 200.
When receiving the binarized data, the printer 200 performs printing based on the binarized data.

(Generation of density correction parameters)
The generation of the density correction parameter will be described.
FIG. 4A shows a dither pattern with an input level 128 (at 256 gradations). The dither pattern is data transmitted to the printer 200 as binary data. FIG. 4B shows a printing result by simulation of the input level 128. As shown in FIGS. 4A and 4B, the density value of the simulation result is different from the density value of the dither pattern. Similarly, although not shown, the density value of the actual printing result is different from the density value of the dither pattern.

In order to compensate for this difference in density value, a density correction parameter is required.
FIG. 5 is a graph showing the relationship between input density and density value. In the graph of FIG. 5, the relationship between the input density and the density value in the actual measurement value (hereinafter sometimes referred to as “density curve”) is shown on the right side of the center. Further, the relationship between the input density and the density value at the target value is shown on the left side from the center.

By interpolating the measured values actually measured (for example, spline interpolation), the density values for all numerical values with the input density of 0 to 100% are determined.
Then, the target value and the actual measurement value at the same input density are compared, and a look table is created based on the comparison result. The created lookup table becomes a density correction parameter. A lookup table is created for each color of toner.

  A case will be described as an example where the target value of the density value is 0.8 when the input density is 50 (%). As shown in FIG. 5, in the actual measurement value, the density value is 0.8 when the input density is 70 (%). Therefore, when 50 (%) is set as the input density, it is converted to 70 (%), and the lookup table is configured to instruct the printer 200.

  In FIG. 5, in order to simplify the description, the input density is described as a numerical value of 0 to 100%. However, in a general personal computer, the density is a numerical value of 0 to 255 for each color of RGB. Expressed. Further, in a general printer, the density is expressed as a numerical value of 0 to 255 for each color of CMYK.

  FIG. 6 is an example of a lookup table for density value conversion. In FIG. 6, the density (%) after conversion is defined in increments of 1 (%) with respect to the input density. The same can be defined when the input density is expressed by a numerical value of 0-255. The step size can be set as appropriate. Further, the converted density of the input density not defined in the lookup table is calculated by interpolation processing.

  FIG. 7A shows a dither pattern at an input level 128 (same as FIG. 4A). FIG. 7B shows a printing result by simulation of the input level 128 corrected by the density correction parameter. As shown in FIGS. 7A and 7B, the density value of the simulation result subjected to density correction is equal to the density value of the dither pattern.

(Printing process)
A printing process executed by the computer 100 will be described. FIG. 8 is a flowchart of the printing process. It is assumed that a program for causing the computer 100 to execute the printing process is stored in auxiliary storage means (for example, the ROM 12). The print process is executed when a print execution instruction is issued from a predetermined application. The printing process is performed for each toner color.

  In S1, it is determined whether or not a full simulation result (density correction parameter) exists. This determination is made based on, for example, whether or not the full simulation result is stored in the auxiliary storage means (for example, the ROM 12). At the time of the first printing after installing the printer driver, there is no full simulation result. Further, even after replacement of consumables such as toner and drums, the full simulation result does not exist (that is, the full simulation result is cleared).

When it is determined that a full simulation result exists (S1: YES), the process proceeds to S2. In S2, normal printing processing is executed. Details of the normal printing process will be described later.
On the other hand, when it is determined that there is no full simulation result (S1: NO), the process proceeds to S3.

In S3, the printer 200 is requested for simulation data.
In S4, simulation data is received.
FIG. 9 is an example of simulation data. As shown in FIG. 9, the simulation data includes the temperature in the printer, the humidity in the printer, and the usage status of each toner.

In S5, a full simulation is executed using the simulation data. A density curve (see FIG. 5) is calculated by the full simulation.
In S6, a density correction parameter (see FIG. 6) is calculated based on the density curve calculated in S5. The calculated density correction curve and density correction parameter are stored, for example, in auxiliary storage means (for example, ROM 12).

  In S7, printing is performed using the density correction parameter calculated in S6 (see FIG. 3).

(Normal printing process)
Next, normal printing processing will be described. 10 and 11 are flowcharts of the normal printing process.
In S11, the printer 200 is requested for simulation data.
In S12, simulation data is received.

  In S13, a first simple simulation is performed. Specifically, for example, the simulation is performed at density values of 10% and 90%. That is, the simulation is performed at locations where there are fewer density values (for example, 1% increments of 1 to 100%) to be simulated during the full simulation.

  In S14, the result of the first simple simulation and the result of the full simulation are compared. Specifically, the 10% density value of the density curve obtained as a result of the full simulation is compared with the 10% density value obtained as a result of the first simple simulation, and the 90% density value of the density curve obtained as a result of the full simulation. The 90% density values of the result of the first simple simulation are compared with each other.

  In S15, it is determined whether or not the difference between the density values compared in S14 is within a predetermined range. If the difference between the density values is within a predetermined range, it is determined that the result of the first simple simulation and the result of the full simulation match. If the difference between at least one of the 10% density value and the 90% density value is not within the predetermined range, it is determined that the simulation results do not match (that is, “NO”). The numerical value within the predetermined range can be set as appropriate.

When it is determined that the density value difference is within the predetermined range (S15: YES), the process proceeds to S22 (FIG. 11).
On the other hand, if it is determined that the density value difference is not within the predetermined range (S15: NO), the process proceeds to S16.

  In S16, a second simple simulation is performed. Specifically, for example, the simulation is performed at density values of 20%, 40%, 60%, and 80%. That is, the simulation is performed at a location where there are fewer density values (for example, 1% increments of 1 to 100%) to be simulated at the time of the full simulation and more than the number of density values simulated at the first simple simulation. .

  In S17, the result of the second simple simulation and the result of the full simulation are compared. Specifically, the 20% density value of the density curve resulting from the full simulation is compared with the 20% density value resulting from the first simple simulation, and the 40% density value of the density curve resulting from the full simulation is 1 Compare the 40% density values of the simple simulation results, compare the 60% density values of the density curves of the full simulation results with the 60% density values of the first simple simulation results, and The 80% density value of the density curve is compared with the 80% density value of the result of the first simple simulation.

  In S18, it is determined whether or not the density value difference compared in S17 is within a predetermined range. If the difference between the density values is within a predetermined range, it is determined that the result of the second simple simulation and the result of the full simulation match. If the difference between at least one of the 20% density value, 40% density value, 60% density value, and 80% density value is not within a predetermined range, the simulation results do not match (that is, “NO” )). The numerical value within the predetermined range can be set as appropriate. Also, a numerical value different from the predetermined range in S15 may be used.

When it is determined that the density value difference is not within the predetermined range (S18: NO), the process proceeds to S24 (FIG. 11).
On the other hand, if it is determined that the difference between the density values is within the predetermined range (S18: YES), the process proceeds to S19.

  In S19, a correction coefficient for the density curve of the full simulation result is calculated. In S20, a density curve is calculated based on the correction coefficient calculated in S19.

The calculation of the correction coefficient and the density curve will be specifically described with reference to FIGS.
FIG. 12 shows the density curve of the full simulation result and the second simple simulation result (plots with input density values of 20%, 40%, 60%, and 80%).

  As shown in FIG. 12, at the input density values of 20%, 40%, 60%, and 80%, the density value of the full simulation result is different from the density value of the second simple simulation result. In order to compensate for this difference, a correction coefficient is required.

For example, it is assumed that the output density value at the input density value 20% in the full simulation is “30” and the output density value at the input density value 40% is “50”.
Further, it is assumed that the output density value at the input density value 20% in the second simple simulation is “36” and the output density value at the input density value 40% is “55”.
In this case, the correction coefficient is “1.2” at an input density value of 20% and “1.1” at 40%. As a result, when the input density value is 30%, it becomes “1.15” ({1.2 + 1.1} / 2) by linear interpolation.

  FIG. 13 shows the density curve of the full simulation result and the density curve of the full simulation result corrected by the correction coefficient.

Returning to FIG. After calculating the density curve in S20, the process proceeds to S21 (FIG. 11).
In S21, a density correction parameter is calculated based on the density curve calculated in S20. In S22, printing is performed using the density correction parameter calculated in S21.

In S23, the user determines whether or not the print result is satisfied. This determination is made based on a user input with respect to the print result.
If it is determined that the user is satisfied with the printing result (S23: YES), the normal printing process is terminated. On the other hand, when it is determined that the user is not satisfied with the print result (S23: NO), the process proceeds to S24.

In S24, a full simulation is performed.
In S25, a density correction parameter is calculated. At this time, a density curve based on the full simulation performed in S24 is used.
In S26, printing is performed using the density correction parameter calculated in S25 (see FIG. 3). The calculated density correction parameter and density curve are stored in auxiliary storage means (for example, ROM 12). The stored density curve is used as a full simulation result in subsequent printing processes.

In S27, the user determines whether or not the print result is satisfied. This determination is made based on a user input with respect to the print result.
If it is determined that the user is satisfied with the printing result (S27: YES), the normal printing process is terminated. On the other hand, when it is determined that the user is not satisfied with the print result (S27: NO), the process proceeds to S28.

In S28, a patch image is formed. Since the processing relating to the generation of the patch image is known, the description thereof is omitted. When the printer 200 has a density sensor, a patch image is formed on an intermediate transfer member, a conveyance belt, or the like. If the printer 200 does not have a density sensor, it is formed on a paper medium.
In S29, the patch image formed in S28 is measured. When the printer 200 does not have a density sensor, measurement is performed by an external measuring device.

In S30, a density curve based on the result measured in S29 is created.
In S31, the simulation coefficient is changed based on the density curve created in S30. The changed simulation coefficient is stored in auxiliary storage means (for example, ROM 12). The stored simulation coefficient is used in the simulation processing (full simulation, first simple simulation, second simple simulation) from the next time onward.

According to the processing described above, if the first simple simulation result and the full simulation result match, the density correction processing is performed based on the full simulation result (hereinafter referred to as “level 1 processing”). .
If the second simple simulation result matches the full simulation result, the full simulation result is corrected, and density correction processing is performed based on the corrected full simulation result (hereinafter referred to as “level 2 processing”). ").
In addition, when the second simple simulation result and the full simulation result do not match, or when the user is not satisfied with the printing result, the full simulation is performed again. Then, density correction processing is performed based on the result of the full simulation performed again (hereinafter referred to as “level 3 processing”).
If the user is not satisfied with the density correction process (printing process) based on the full simulation result, the simulation coefficient is updated (hereinafter referred to as “level 4 process”).

FIG. 14 is a table showing differences in processing at each level.
In the level 1 processing, only the first simple simulation is executed, so that the existing full simulation result can be used. Therefore, it is not necessary to perform a new full simulation.

  In the level 2 processing, the second simple simulation is executed, the existing full simulation result is corrected based on the result, and the corrected full simulation result can be used. Therefore, it is not necessary to perform a new full simulation.

  In the level 3 processing, a new full simulation is newly performed, and the density correction parameter is updated based on the full simulation result. The updated density correction parameter and density curve are used in the next and subsequent simulation processes (full simulation, first simple simulation, and second simple simulation).

  In the level 4 processing, the simulation coefficient used in the full simulation is updated based on the measured value of the formed patch image. If the printer 200 does not have a density sensor, the density value of the patch image is measured by an external measuring device.

  According to the first embodiment described above, if the first simple simulation result and the full simulation result match, the density correction process is performed based on the full simulation result. If the second simple simulation result matches the full simulation result, the full simulation result is corrected, and density correction processing is performed based on the corrected full simulation result. In addition, when the second simple simulation result and the full simulation result do not match, or when the user is not satisfied with the printing result, the full simulation is performed again. Then, density correction processing is performed based on the result of the full simulation performed again. If the user is not satisfied with the density correction process (printing process) based on the full simulation result, the simulation coefficient is updated. Thereby, the existing full simulation result can be used effectively, and the number of execution times of the full simulation can be reduced.

[Second Embodiment]
A second embodiment of the present invention will be described. In the second embodiment, when the second simple simulation is performed, the comparison with the full simulation result is not performed.

FIG. 15 is a flowchart of normal printing processing in the second embodiment.
In S41, the process of S11-S14 (refer FIG. 10) is performed.
The processes of S42, S43, S44, S45, and S46 are the same as the processes of S15, S16, S19, S20, and S21, respectively. However, after the second simple simulation is executed (S43), the correction coefficient is calculated without comparing with the full simulation result.
The processing of S47 to S49 is the same as the processing of S22 to S31.

  According to the second embodiment described above, if the first simple simulation result and the full simulation result match, the density correction process is performed based on the full simulation result. If the second simple simulation result matches the full simulation result, the full simulation result is corrected, and density correction processing is performed based on the corrected full simulation result. In addition, when the second simple simulation result and the full simulation result do not match, or when the user is not satisfied with the printing result, the full simulation is performed again. Then, density correction processing is performed based on the result of the full simulation performed again. If the user is not satisfied with the density correction process (printing process) based on the full simulation result, the simulation coefficient is updated. Further, when the second simple simulation is performed, printing is performed without comparing with the full simulation result, and it is determined whether to perform the full simulation again based on the user input. Thereby, the frequency | count of execution of a full simulation can be reduced.

The present invention is not limited to the above-described embodiments, and it goes without saying that various improvements and modifications can be made without departing from the scope of the present invention.
Further, each flowchart described above is merely an example, and the processing may be realized by another flowchart as long as a result equivalent to the processing of each flowchart can be obtained.
Furthermore, some processes in the flowchart described above may be omitted or another process may be added.

It is the figure which showed an example of the structure of the system which implement | achieves this invention. It is the block diagram which showed an example of the internal structure of a computer. It is the figure which showed the flow of a process with a computer and a printer at the time of printing. It is the figure which showed the relationship between a dither pattern and a simulation result. 5 is a graph showing the relationship between input density and density value. It is the figure which showed an example of the look-up table for density value conversion. It is the figure which showed the relationship between a dither pattern and a simulation result. It is a flowchart of a printing process. It is an example of the data for simulation. It is a flowchart of a normal printing process. It is a flowchart of a normal printing process. It is the graph which showed the density curve and simple simulation result of full simulation. It is the graph which showed the density curve of the full simulation, and the corrected density curve. It is the table | surface which showed the difference of each process level. It is a flowchart of a normal printing process.

Explanation of symbols

11 CPU
12 ROM
13 RAM
14 Input I / F
15 Communication I / F
100 computer 200 printer

Claims (12)

Based on the simulation parameters stored in the first storage means, a simulation value of a first predetermined number of density values among all density values is calculated,
Of the full simulation values of all the density values calculated based on the simulation parameters stored in the first storage means, simulation values corresponding to the first predetermined number of density values are obtained from the second storage means. Acquired,
Compare the calculated simulation value and the acquired simulation value,
If it matches,
Correcting the print data based on the full simulation value stored in the second storage means;
If they do n’t match,
Based on the simulation parameters stored in the first storage means, a simulation value of a second predetermined number of density values larger than the first predetermined number among all density values is calculated,
Based on the calculated simulation value, the full simulation value is corrected,
Correcting the print data based on the corrected full simulation value;
Image processing method. When certain conditions are met,
Based on the simulation parameters stored in the first storage means, a full simulation value of all concentration values is calculated,
Updating the second storage means based on the calculated full simulation value;
The image processing method according to claim 1. The predetermined condition is:
The simulation value of the second predetermined number of density values does not match the acquired simulation value, and / or
Received input related to instructions to calculate full simulation values for all concentration values.
The image processing method according to claim 2. When a given user input is accepted,
Print a measurement image,
Measure the density of the printed measurement image,
Based on the measured concentration, calculate the simulation parameters,
Updating the first storage means based on the calculated simulation parameters;
The image processing method according to claim 1. On the computer,
Calculating a simulation value of a first predetermined number of density values out of all density values based on the simulation parameters stored in the first storage means;
Of the full simulation values of all the density values calculated based on the simulation parameters stored in the first storage means, simulation values corresponding to the first predetermined number of density values are obtained from the second storage means. Step to get,
Comparing the calculated simulation value with the acquired simulation value;
If it matches,
Correcting print data based on a full simulation value stored in the second storage means;
If they do n’t match,
Calculating a simulation value of a second predetermined number of density values greater than the first predetermined number among all density values based on the simulation parameters stored in the first storage means;
Correcting the full simulation value based on the calculated simulation value;
Correcting print data based on the corrected full simulation value;
An image processing program for executing When certain conditions are met,
Calculating a full simulation value of all concentration values based on the simulation parameters stored in the first storage means;
Updating the second storage means based on the calculated full simulation value;
An image processing program according to claim 5 for causing a computer to execute. The predetermined condition is:
The simulation value of the second predetermined number of density values does not match the acquired simulation value, and / or
Received input related to instructions to calculate full simulation values for all concentration values.
The image processing program according to claim 6. When a given user input is accepted,
Printing a measurement image;
Measuring the density of the printed measurement image;
Calculating the simulation parameter based on the measured concentration;
Updating the first storage means based on the calculated simulation parameters;
8. An image processing program according to claim 5, wherein the image processing program is executed by a computer. First storage means for storing simulation parameters;
Second storage means for storing full simulation values of all the concentration values calculated based on the simulation parameters stored in the first storage means;
First simulated value calculating means for calculating a simulation value of a first predetermined number of density values among all density values based on the simulation parameters stored in the first storage means;
Of the full simulation values of all the density values calculated based on the simulation parameters stored in the first storage means, simulation values corresponding to the first predetermined number of density values are obtained from the second storage means. First acquiring means for acquiring;
Comparison means for comparing the calculated simulation value with the acquired simulation value;
Means for correcting the print data based on the full simulation value stored in the second storage means if they match,
If they do not match, based on the simulation parameters stored in the first storage means, a second predetermined number of density values greater than the first predetermined number among all density values are simulated. A second simulated value calculating means for calculating a value;
A full simulation value correcting means for correcting the full simulation value based on the calculated simulation value when they do not match;
Print data correction means for correcting print data based on the corrected full simulation value if they do not match,
An image processing apparatus. Full simulation value calculation means for calculating full simulation values of all concentration values based on simulation parameters stored in the first storage means when a predetermined condition is satisfied;
Updating means for updating the second storage means based on the calculated full simulation value when a predetermined condition is satisfied;
The image processing apparatus according to claim 9. The predetermined condition is:
The simulation value of the second predetermined number of density values does not match the acquired simulation value, and / or
Received input related to instructions to calculate full simulation values for all concentration values.
The image processing apparatus according to claim 10. A measurement image printing means for printing a measurement image when a predetermined user input is received;
Measurement means for measuring the density of the printed measurement image when a predetermined user input is received;
A simulation parameter calculation means for calculating the simulation parameter based on the measured concentration when a predetermined user input is received;
First storage means updating means for updating the first storage means based on the calculated simulation parameter when a predetermined user input is received;
The image processing apparatus according to claim 9, further comprising: