JP2006035745A - Optimum value acquiring device, optimum value acquiring program, optimum value acquiring method, calibration device, calibration program and calibration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable positively and effectively setting a plurality kinds of parameters affecting noise to an optimum value. <P>SOLUTION: In acquiring an optimum parameter value for operating a printer, one kind of parameter is successively changed to set the parameter for printing a patch, relative to the printer for which at least two or more kinds of parameters are set to drive, to acquire distribution information showing the distribution of a recording material in relation to the patch. In a process for acquiring a parameter value to be set as a kind of parameter which is successively changed so as to suppress noise based on the acquired distribution information, a kind of parameter relatively largely affecting the noise generation degree is processed prior to the kind of parameter relatively less affecting the noise generation degree. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for acquiring a parameter for suppressing noise.

In a printing apparatus such as an ink jet printer, calibration is performed by a process before product shipment or an end user operation so that printing can be executed with the least noise. In order to carry out calibration, it is necessary to detect the state of noise generation and to understand what kind of setting can drive the noise most. As such a noise detection technique, for example, a technique for detecting banding noise generated with some periodicity in the main scanning direction (direction perpendicular to the paper feed) is known. (For example, see Patent Document 1)
JP 2003-219158 A

In the conventional technology described above, it has been difficult to reliably and efficiently set a plurality of types of parameters that affect noise to optimal values.
That is, in the above technique, banding noise at a certain parameter value can be evaluated, but when there are multiple types of parameters that affect noise, each parameter is set to an optimal value reliably and efficiently. I can't. More specifically, even if the parameter value is changed to a dark cloud for multiple types of parameters, the noise is most affected, for example, by changing one type of parameter, the set parameter values for other types of parameters may not be optimal. It was difficult to obtain combinations of parameter values to be suppressed.
The present invention has been made in view of the above problems. An optimum value acquisition device, an optimum value acquisition program, an optimum value acquisition method, a calibration device, and a calibration device that reliably and efficiently set multiple types of parameters to optimum values. The purpose is to provide a calibration program and a calibration method.

  In order to achieve the above object, the present invention is configured so that the parameter value of a certain type of parameter can be changed, and a patch is printed by each parameter value. As a result, a patch printed with a plurality of parameter values is obtained. In the obtained patch, since the recording material is recorded in a distribution reflecting each parameter value, the degree of noise generation in each patch can be evaluated by referring to the distribution information indicating this distribution. Therefore, according to this evaluation, it is possible to obtain a parameter value to be set in order to suppress noise most.

  The printing apparatus according to the present invention can be driven by setting at least two types of parameters. If the patch is printed for each of a plurality of types of parameters, the set values (parameter values) of the types of parameters are set. Can be obtained by sequentially changing. Therefore, by repeating the processing by the printing unit and the parameter value acquisition unit, it is possible to acquire a parameter value that can suppress noise most in each type of parameter.

  However, in the present invention, a parameter value to be set for a certain type of parameter is acquired by the processing by the printing unit and the parameter value acquiring unit, and another type of parameter is set in a state in which the parameter value is set. In obtaining the parameters to be set, the types of parameters to be set first are specified. Thereby, a plurality of types of parameters can be set to optimum values reliably and efficiently.

  In other words, the degree of noise generation usually changes depending on the parameter value change, but when the degree of influence on the degree of noise generation is compared for each type of parameter, the degree of influence that the change of the parameter value has on the degree of noise occurrence differs. Therefore, for each parameter type, it is possible to define whether the parameter has a relatively large effect on the degree of noise generation or a relatively small effect. If there are two types of parameters, they are relatively large and small, but if there are two or more types of parameters, the order of influence is given.

  In any case, it is possible to define the degree of influence on the degree of noise generation for each parameter type, and for types of parameters that have a relatively large influence on the degree of noise generation, the types that have a relatively small influence The processing by the printing unit and the parameter value acquisition unit is performed prior to the parameters. If a parameter value that suppresses noise is obtained for a type of parameter (called type A) that has a relatively large effect on the degree of noise generation and is fixed to this value, noise that may be generated due to the type A parameter Can be as small as possible.

  Therefore, after that, even if the parameter value that suppresses noise is changed for a parameter of a kind that has a relatively small effect (called kind B), a large noise fluctuation that can occur due to the kind A parameter is Does not occur. In addition, the noise that can be generated due to the type B parameter can be reduced to the smallest level. As a result, in the situation where the parameter values of type A and type B are combined, it is possible to set so that the degree of noise generation is substantially minimized.

  Incidentally, noise is formed by reading with banding noise (noise periodically generated in the sub-scanning direction) generated substantially parallel to the main scanning direction and noise caused by dust adhering to the patch (with dust attached). Noise), noise at the time of reading, and noise recorded at the time of patch printing. The distribution information indicates the distribution of the recording material, and the distribution information is affected by noise included in the patch and noise when acquiring the distribution information. Therefore, if the distribution information is acquired, the noise for each patch can be evaluated, and the parameters to be set for suppressing the noise can be acquired.

  When acquiring the distribution information, it is only necessary to acquire data reflecting the distribution of the recording material recorded in the printed patch. Therefore, it is possible to employ a configuration in which the patch is scanned by the optical reader. When acquiring the distribution information indicating the distribution of the recording material, it is difficult to acquire data that accurately indicates only the distribution of the recording material, and the recording material is accurately recorded as intended before calibration. It is not easy to generate a patch. Therefore, the above-mentioned noise is included in the distribution information.

  The printing means only needs to be able to set a parameter value and drive the printing apparatus with the parameter value to print a patch. Therefore, the printing unit can be configured by a print control module such as a printer driver for controlling the printing apparatus. The parameter may be a variable value that affects the degree of noise generation and may be a setting value for driving the printing apparatus, or a setting used by a computer or the like that controls the printing apparatus. It may be a value and various configurations can be adopted. Of course, it is not essential that the parameter value be any numerical value, and there is a variable situation when the printing apparatus is driven, and it is sufficient that the situation can be specified.

  Further, the parameter may be a parameter that is set when the printing apparatus is driven, and may be a parameter that can vary the degree of noise generation by changing its value. For example, a setting value that affects the position in the sub-scanning direction of the recording material to be recorded by the printing apparatus can be adopted as a parameter. If this parameter is changed, the position in the sub-scanning direction on which the recording material is recorded can vary, so that the occurrence of a line (banding noise) extending in the main scanning direction perpendicular to the sub-scanning direction varies. Therefore, it is possible to acquire a parameter for suppressing banding noise by sequentially changing this parameter and printing a patch.

  More specifically, the feed amount when feeding the print medium in the printing apparatus can be used as a parameter in the present invention. In other words, if the paper feed amount is changed, the distance between rasters parallel to the main scanning direction may change, so the degree of occurrence of banding noise parallel to the main scanning direction may change. For example, banding noise caused by the distance between rasters can be suppressed.

  Further, in a printing apparatus that ejects ink from a plurality of nozzles, when configured to be able to set a nozzle to be used among the plurality of nozzles, information indicating the setting of the nozzle to be used can be the above parameter. In other words, the ink flying characteristics from a plurality of nozzles (such as the direction and speed of ink flying) are manufactured to be substantially the same for all nozzles, but some of them have different flying characteristics from other nozzles. There are also nozzles. In this case, since the ink recorded by this nozzle is shifted from the ideal position, it may cause noise such as banding noise parallel to the main scanning direction. Therefore, if the nozzles to be used are made variable according to the parameters, noise caused by the ink flying characteristics can be suppressed.

  When the above two parameters are compared, in general, the parameter for specifying the feed amount when the recording medium is fed in the printing apparatus is a plurality of nozzles formed on the print head of the printing apparatus. This greatly contributes to the degree of noise generation than the parameters for specifying the nozzles in use. That is, the noise caused by the former change is more noticeable than the noise caused by the latter change.

  Of course, other types of parameters may be employed. For example, it is possible to adopt a parameter for specifying the feed speed when feeding the recording medium in the printing apparatus. That is, in a printing apparatus, a recording medium is usually conveyed by a predetermined path using a pinch roller or the like, but the recording medium has the same driving force when the friction coefficient of the pinch roller differs for each machine of the printing apparatus. Even if is sent, the feed amount may be different. That is, even if the parameter is not a parameter that directly specifies the feed amount but is a parameter that specifies the feed rate, the feed amount can be changed by changing the setting.

  Therefore, there is a case where the recording medium feeding speed can be adjusted by adjusting the torque transmitted to the pinch roller or the rotational speed of the motor. In this case, the feeding speed of the recording medium is specified by a parameter, and this parameter is a parameter in the present invention. As described above, if the feed speed can be adjusted by the parameter, this parameter can be used as a parameter of the present invention, and a parameter value to be set to suppress noise can be acquired. In general, when the friction coefficient of the pinch roller is relatively small, the feeding speed tends to increase, and when the friction coefficient of the pinch roller is relatively large, the feeding speed tends to decrease.

  In addition, a parameter for specifying the amount of recording material to be recorded per unit dot in the printing apparatus can be adopted as the parameter of the present invention. For example, it is possible to adjust the force applied to ink when ejecting ink droplets in an ink jet printer, or to adjust the laser irradiation timing so that the amount of toner per dot can be changed in a laser printer. Sometimes. If the amount of recording material to be recorded per unit dot is reduced, noise due to unintentional exposure of the background color of the recording medium is likely to occur, and if the amount of recording material is increased, the recording materials are not intended to each other Noise is likely to occur due to overlapping. Therefore, if the configuration is such that the amount of the recording material can be adjusted by a parameter, this parameter can be used as a parameter of the present invention, and a parameter value to be set to suppress noise can be acquired.

  Furthermore, a parameter for specifying the suction force when sucking the recording medium to the platen in the printing apparatus can be adopted as the parameter of the present invention. That is, when the recording medium is a large sheet, a printing sheet suction portion may be formed on the platen in order to stabilize the sheet posture. For example, a hole is formed in the platen, and a negative pressure is applied by a fan or the like to attract the printing paper to the platen. In this case, when the suction force is increased, the frictional force between the platen and the printing paper increases. As a result, the printing paper feed speed and feed amount may vary. Therefore, if the negative pressure can be adjusted by the parameter, this parameter can be used as a parameter of the present invention, and a parameter value to be set to suppress noise can be acquired.

  In the above parameters for specifying the feed speed, the parameter for specifying the amount of the recording material, and the parameter for specifying the suction force, generally, the parameter of the feed speed, the recording material, The effect on the noise becomes smaller in the order of the parameter and the suction force parameter. In comparison with these parameters, in general, the parameter that directly specifies the feed amount and the parameter that specifies the used nozzle have a greater influence on noise.

  The above parameters are parameters that change some state in the printing apparatus. However, when there are options as processing in a print control module such as a printer driver, a parameter for specifying a selection result is adopted as a parameter of the present invention. Also good. For example, a parameter for specifying a profile to be referred to when converting a color system of image data indicating an image to be printed can be used as a parameter of the present invention.

  That is, in a printing apparatus, in order to express an image to be printed in a color system that uses the color of a recording material used in the printing apparatus as a color component, the color system of image data representing the image to be printed is converted. . At this time, a plurality of profiles can be prepared and configured to be selectable according to printing conditions and the like. Therefore, if any one of the selectable profiles is specified by a parameter, this parameter can be used as a parameter of the present invention, and a parameter value to be set to suppress noise can be acquired.

  Further, in the printing apparatus, there are cases where the recording material per unit dot is variably configured. For example, there is a case in which the recording weight of the recording material for one dot can be changed to four levels of large / medium / small and no recording. In this case, normally, the gradation value that specifies the gradation for each color of the unit dot is converted to the gradation value that specifies the gradation for each large, medium, and small dot. At this time, the conversion is performed with reference to a profile that defines the correspondence between the former gradation value and the latter gradation value.

  In this profile, various correspondences can be adopted as options, such as different correspondences for each printing medium, or changing the correspondences in consideration of the graininess and the maximum recording amount of the recording material with respect to the recording medium. Therefore, if a plurality of selectable profiles are prepared and one of them is specified by a parameter, this parameter can be used as a parameter of the present invention, and a parameter value to be set to suppress noise is obtained. can do.

  Furthermore, the image data indicating the image to be printed has multiple gradations (usually 256 gradations), and the gradations that can be expressed by the unit dots of the printing apparatus are small gradations (usually 2 gradations or 4 gradations). It is. Therefore, in general, gradation number conversion processing for reducing the number of gradations is performed, and various algorithms such as error diffusion and dithering exist in the gradation number conversion processing. Various values can be adopted as thresholds that can be selected in various algorithms. Therefore, if the algorithm type and selectable threshold value are specified by parameters, this parameter can be used as a parameter of the present invention, and a parameter value to be set to suppress noise can be acquired.

  Needless to say, in addition to this, if the configuration is such that the option is specified by a parameter for a process in which the option can exist, this parameter can be used as the parameter of the present invention. For example, when using dark and light inks together for a recording material of a certain hue, a gradation value of a certain color can be converted to a dark and light ink gradation value by referring to a profile. At this time, if a plurality of profiles are prepared and can be selected, a parameter for specifying this option can be used as a parameter of the present invention. As described above, when there are choices in parameter types as processing in the print control module, if the influence of various parameters on noise is measured in advance, the processing targets can be processed in descending order of influence.

  In the present invention, since noise is detected by grasping the distribution state of the recording material in the patch, this patch is preferably a patch that can easily detect noise. For example, if banding noise that occurs parallel to the main scanning direction and occurs in a certain period in the sub-scanning direction is detected, the main scanning direction and the sub-scanning noise are so large as to be sufficient to detect this noise. The number of pixels in the scanning direction may be determined. In order to evaluate banding noise under various conditions, it is preferable to arrange a plurality of patches printed under a plurality of conditions in the main scanning direction. For example, it is possible to employ a configuration in which patches are printed for each of a plurality of colors while the parameter values are fixed, and these patches are arranged in the main scanning direction.

  Furthermore, as a configuration suitable as a patch arranged in the main scanning direction, a configuration in which patches are arranged at substantially symmetrical positions across the center position of the main scanning in the printing apparatus may be adopted. That is, the main scanning is normally in a direction perpendicular to the feeding direction of the printing medium, and it is ideal that the feeding amount is constant in the main scanning range, but the feeding amount is not constant in the main scanning range. This can cause noise. Therefore, it is possible to easily detect whether the feed amount is appropriate or not by printing a patch at a symmetrical position across the center position of the main scanning and comparing the noise generation states of the two. As a matter of course, various causes other than the feeding amount of the recording medium are assumed as causes for generating different levels of noise at both ends in the main scanning direction.

  In the present invention, it is preferable that one patch is configured to be uniform in color and uniform in order to make noise clearly appear. Further, in order to reliably compare whether or not the degree of noise generation differs depending on the position of main scanning, it is preferable that the colors of patches to be compared are the same color (that is, patches printed based on the same image data). . In addition, the patch may be arranged at a substantially symmetrical position across the center position of the main scanning, but if it is considered that the difference in noise generation level occurs most at both ends of the main scanning, the patch is located as close to the end as possible. It is preferred to print the patch. Of course, the degree of noise generation may vary depending on the color of the patch. Therefore, in order to make the difference due to the color obvious, the number of colors is not limited to one, but the patch is printed with a plurality of colors. preferable. A configuration in which one color patch is arranged at both ends in the main scanning direction and another color patch is added may be employed.

  Furthermore, it is preferable that the patch includes a color in which noise is easily recognized by human eyes. The colors recognized by the human eye vary from person to person, but in general, achromatic colors are easier to recognize color differences (color differences) than chromatic colors. Therefore, if an achromatic color is included in the patch and noise is detected by the achromatic color, it is possible to detect noise corresponding to the perception by human eyes. Of course, it is preferable to include a color other than an achromatic color in the patch if it is a color in which noise is easily recognized.

  Moreover, you may employ | adopt other than a human as a reference | standard which judges whether noise is conspicuous. That is, depending on the type of printing apparatus and the type of recording material mounted on the printing apparatus, noise may be noticeable in a specific color. In such a case, a patch of a different color is printed for each printer type and each recording material type. As a result, it is possible to reliably detect noise regardless of the type of printing apparatus and the type of recording material. In determining this color, a plurality of colors may be printed for each printer type and each type of recording material, and a color that generates noise relatively frequently among them may be selected.

  Further, when printing a patch, it is preferable to use recording materials of all colors that can be used in the printing apparatus. For example, all colors may be used for printing one color patch, or a recording material of all colors may be included in any one of two or more patches. That is, a specific color can greatly affect noise generation, so if you print a patch using all colors in a situation where such noise can occur, the noise will be reduced in any patch. Can be detected. Therefore, the generation of noise is not overlooked. Further, since recording materials of all colors can be used when actually operating the printing apparatus, it is not sufficient to evaluate the degree of noise generation using only a single color or only a part of colors. Therefore, by printing patches using recording materials of all colors, it is possible to evaluate noise that may occur during actual operation.

  As an example where a specific color greatly affects noise generation, the flying direction of an ink droplet flying from a specific nozzle for ejecting a specific color in an inkjet printer is different from the flying direction of an ink droplet from another nozzle. For example, there may be a case where one of the nozzles ejecting ink of a certain color has a different pitch from the other nozzles due to nozzle manufacturing errors. Of course, not only an ink jet printer but also a laser printer or the like, a specific color can greatly contribute to the generation of noise as long as it is configured to express multiple colors by combining a plurality of colors.

  Furthermore, it is possible to employ a configuration in which a patch including two colors, a color having a predetermined brightness and a color having a lower brightness, is printed. That is, a part that becomes unintentionally low in the high brightness color becomes noise, and a part that becomes unintentionally high in the low brightness color becomes noise. Therefore, if a high-lightness patch and a low-lightness patch are employed as the above-described patches, any noise can be detected. Here, as an example in which a part having a low lightness unintentionally occurs in a high lightness color, there is a case where recording materials are unintentionally overlapped and recorded. On the contrary, as an example in which a part having a high lightness unintentionally occurs with a low lightness color, the recording material is unintentionally recorded away and the ground color (usually white) of the recording medium is exposed. There are cases.

  Here, it is only necessary to print the patch with two different types of lightness, but it is preferable that the lightness of the two be separated from each other to some extent in order to make noise clearly appear for the colors of different lightness. For example, when the brightness value range is 0 to 100, it is possible to employ an example in which a patch having a brightness of 55 and a patch having a brightness of 35 are printed.

  The parameter value acquisition unit only needs to be able to evaluate the degree of noise generation in each patch based on the distribution information and acquire the parameter value to be set in order to minimize the noise. For this purpose, various configurations can be adopted, and a distribution characteristic value indicating a characteristic in which the recording material is distributed is calculated, and a value indicating the degree of noise generation is calculated for each patch based on the distribution characteristic value. A configuration can be adopted. The distribution characteristic value may be an index value that evaluates the degree of noise generation. For example, an index value that increases as more noise is generated can be employed. More specifically, a configuration using a value obtained by converting distribution information into a spectrum with respect to a spatial frequency can be employed. Since the spectral value obtained by the conversion to the spatial frequency forms a peak when periodic noise is included, the degree of occurrence of the periodic noise can be evaluated. Of course, the spectrum may be integrated.

  If a value capable of evaluating the degree of occurrence of noise is calculated, a parameter value that suppresses noise can be acquired by selecting a parameter value having the smallest value indicating the degree of occurrence of periodic noise. In addition, since banding noise is generated in a certain period in the sub-scanning direction, if the banding noise is evaluated, a change in the main scanning direction of each patch is averaged and the like is distributed in one dimension (sub-scanning direction). Noise can be evaluated using information.

  In the parameter value acquisition means, it is possible to introduce additional processing for reliably detecting noise. For example, a patch printed on a recording medium may be divided into smaller areas, and the degree of noise generation may be acquired for each area. As described above, when the processing is advanced for each divided region, it is possible to evaluate the noise for each divided region, not for the patch as a whole. Therefore, by comparing the distribution information for each divided region and extracting / removing a region having a unique distribution, it is possible to previously remove noise included only in the specific divided region. In addition, preprocessing for emphasizing a part affected by noise in the distribution information in advance may be introduced. According to this processing, it is possible to make noise more obvious and to more reliably evaluate the degree of noise generation.

  When printing a plurality of patches with one parameter value, a parameter value that suppresses noise most can be grasped by adding a value indicating the degree of noise generation for each parameter value. That is, when a plurality of patches are printed with different conditions such as patch color for one parameter value, the degree of noise generation may be different for each patch. Therefore, by performing the summation as described above, by comparing the summed values, noise generation based on a plurality of patches can be performed as a whole (a plurality of conditions under which the patch is printed). It can be easily determined whether it can be suppressed.

  It should be noted that before the value indicating the degree of noise generation is calculated by the parameter value acquisition means, if additional preprocessing (patch division or noise enhancement processing) is performed as described above, A configuration may be adopted in which a relative value is calculated as a value indicating the degree of occurrence, and the total value of the relative values is compared. That is, when performing the pre-processing, different pre-processing may be performed for different patches. For example, even if noise is emphasized, the degree of enhancement may be changed depending on the color of the patch and the printing conditions. In such a case, normalization can be performed by calculating a relative value between patches that have been subjected to the same preprocessing without directly comparing values indicating the degree of noise generation between patches having different enhancement levels. it can. If it is the value after this normalization, it can be added and compared for each parameter. The same preprocessing corresponds to a case where the degree of enhancement (coefficient) and the conditions for determining the degree of enhancement are the same.

  Furthermore, if the degree of noise generation can be evaluated as described above, it can be determined whether or not the adjustment is insufficient to select the best parameter. For example, it may be determined whether or not a value indicating the degree of noise generation satisfies a predetermined criterion. If the standard is not met, various actions can be taken, but it is necessary to redo the adjustment in the printing device because the printing device is defective, or to select a parameter value that minimizes noise by referring to the printed patch. This is possible.

  As in the present invention, when there are a plurality of types of parameters that have different effects on the degree of noise generation, different measures can be taken depending on the level of noise generation. For example, it is possible to determine whether or not a patch that can suppress noise is included in a printed patch depending on whether or not the above criterion is satisfied. However, there is a type of parameter that has a relatively large influence on the degree of noise generation. If the standard is not satisfied, it is preferable that the printing apparatus is defective.

  That is, it is possible to largely adjust the degree of noise generation by changing this type of parameter, but if this parameter change does not satisfy the criteria, it is preferable to perform readjustment considering that the printing apparatus is defective. . For example, when the printing mechanism (carriage height, etc.) in the printing apparatus is not sufficiently adjusted, it is often the case that the degree of noise generation cannot be made sufficiently small only by changing parameter values. Therefore, the printing mechanism is readjusted. Since the readjustment of the printing mechanism is often a manual operation, the optimum value acquisition device displays a message indicating that the printing device is defective on a predetermined display device in order to prompt readjustment.

  Even if the type of parameter that has a relatively small effect on the degree of noise generation does not meet the above criteria, the parameter value that suppresses noise has already been set for the type of parameter that has a relatively large effect, The degree of noise generation is not large. Therefore, it is preferable to select a parameter value that can suppress noise as much as possible based on the printed patch. For this reason, it is configured so that any one of the parameter values set when the patch is printed by a predetermined input device can be designated and input, and the parameter value for suppressing noise is acquired by receiving this designation. Of course, in order to select a parameter, it may be devised such that a value indicating the degree of noise generation in each patch is output by a predetermined output device.

  The predetermined criterion may be a criterion for determining whether or not the noise generation level is within the allowable range. For example, when the noise generation level is expressed by a numerical value, the allowable range is set. The threshold value to be shown may be determined in advance. It is possible to determine whether or not there is a large difference in the level of noise generation between the left and right of the main scan, and it is possible to determine whether or not it is a defective aircraft, and various configurations are adopted. Is possible. Of course, it is possible to define different criteria for each parameter type, for example, different threshold values.

  Further, as a configuration example suitable for acquiring the distribution information of the recording material in the patch by the optical reading device, a configuration in which the light source emits light prior to the acquisition of the distribution information can be adopted to stabilize the light source. At this time, the light source may simply be emitted, or a preview scan (simple scan at a lower resolution than the main scan) normally provided in the optical reader may be performed. Of course, preview scanning and light emission from the light source may be performed a plurality of times. Furthermore, in order to reduce the influence of the reading variation of the optical reader as much as possible when acquiring the distribution information, averaging is performed by performing multiple readings, or the last or the last multiple reading results by performing multiple readings. It is possible to adopt a configuration for acquiring distribution information based on the above. Alternatively, reading may be performed a plurality of times, and a value for evaluating the noise may be calculated and averaged.

  In addition, as described above, a configuration in which processing is performed before parameters of a type that has a relatively small effect on types of parameters that have a relatively large effect on the degree of noise generation can be used during calibration. It is. That is, setting is performed so that the printing apparatus is driven with the acquired optimum value. According to this setting, the printing apparatus can be driven with a parameter that minimizes the generation of noise. Of course, when there are two or more types of parameters, pay attention to the two types of parameters, one is the first parameter, the other is the second parameter, and the first parameter is changed to print the patch. It is possible to implement the present invention by using a configuration in which a parameter that suppresses noise most is set, a second parameter is changed, a patch is printed, and a parameter that suppresses noise most is set. it can. That is, the parameter is defined so that the change of the first parameter has a greater influence on the degree of noise generation than the change of the second parameter.

  By the way, such an apparatus may exist as a single apparatus, or may be used in a state of being incorporated in a certain device, but the idea of the invention is not limited to this and includes various aspects. It is a waste. Therefore, it can be changed as appropriate, such as software or hardware. The invention according to claims 14 and 15 may be adopted as an example in which the software of the apparatus is realized as an embodiment of the idea of the invention.

  Of course, the recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium that will be developed in the future. The same is true for the replication stage of the primary replica and secondary replica. In addition, even when a part is software and a part is realized by hardware, the idea of the invention is not completely different, and a part is stored on a recording medium and is appropriately changed as necessary. It may be in the form of being read.

  Further, in such an apparatus, when proceeding with the process according to the control procedure, it is natural that the invention exists at the basis of the procedure, and the method can also be applied. Therefore, the inventions according to claims 16 and 17 basically have the same action. Of course, it is also possible to adopt configurations corresponding to the above-mentioned claims 2 to 11 and claim 13 in the above program and method.

Here, embodiments of the present invention will be described in the following order.
(1) General configuration of the present invention:
(2) Configuration of calibration system:
(2-1) Computer configuration:
(2-2) Configuration of adjustment pattern:
(2-3) Configuration of calibration module:
(2-4) Printer configuration:
(3) Calibration process:
(3-1) Adjustment pattern printing process:
(3-2) Scan processing:
(3-3) Best value extraction process:
(4) Banding noise value calculation example:
(5) Other embodiments:

(1) General configuration of the present invention:
FIG. 1 is an explanatory diagram for explaining the outline of the present invention. In the figure, a printer 40 is an ink jet printer that can perform printing using a printing paper having a large size such as A2 size, and ejects ink droplets from a plurality of nozzles to record an image on the printing paper. In this embodiment, the feeding amount of printing paper and the nozzles used in the printer 40 are adjusted to suppress the occurrence of unintentional linear noise (banding noise) in the main scanning direction.

  For this reason, an adjustment system is formed by the printer 40, the computer 10 that controls the printer 40, and the scanner 30 at the time of adjustment. That is, the adjustment pattern including a plurality of patches is printed on the printing paper by the printer 40, the adjustment pattern is scanned by the scanner 30, and the banding noise is evaluated based on the scan result, thereby suppressing the banding noise. Get possible adjustment values.

  Here, in order to adjust to the optimum state with respect to the feeding amount of the printing paper and the selection of the nozzle to be used, which are factors that affect the banding noise, an adjustment pattern for each adjustment is used. That is, first, in order to adjust the feed amount first, the feed amount is changed in the printer 40 and the same adjustment pattern is printed a plurality of times. If these adjustment patterns are captured by the scanner 30 and the banding noise states are compared between different feed amounts, the feed amount that can suppress the banding noise most can be acquired. Therefore, if the feed amount is set to the printer 40 so that the printing paper is fed with the optimum feed amount, the printer 40 can be driven with the feed amount that can suppress the banding noise most.

  Further, in order to grasp the optimum use nozzle in a state where the feed amount is set, the same adjustment pattern is printed a plurality of times by changing the nozzle used at the time of printing. If a similar analysis process is performed on the print result, a set of used nozzles that can suppress the banding noise most can be acquired. Therefore, if the printer 40 is set to execute printing using the obtained set of used nozzles, the printer 40 can be driven using the set of nozzles that can suppress the banding noise most. The present invention may be performed by the manufacturer of the printer 40 before shipping, or by the user of the printer 40.

  In the present embodiment, the feed amount that affects the banding noise and the combination of the nozzles used can be changed, and the feed amount that greatly affects the degree of occurrence of the banding noise is adjusted first. That is, if a factor that has a relatively small influence on the degree of occurrence of banding noise is adjusted first, the degree of occurrence of banding noise may vary greatly when adjustments are made later on other factors.

  As a result, the adjustment of the factor having the relatively small effect is substantially meaningless, and this factor may need to be adjusted again. However, in the present invention, the factors that have a relatively large influence on the degree of occurrence of banding noise are adjusted first, so even if other factors are adjusted after this adjustment, the factors that have already been adjusted are adjusted. There will be no effect to the extent that changes. Therefore, by adjusting the factors that have a relatively large influence in advance, it is possible to reliably and efficiently set a plurality of factors to the optimum state.

(2) Configuration of calibration system:
(2-1) Computer configuration:
Next, a configuration for realizing the above-described invention will be described in detail. FIG. 2 is a block diagram showing functions of the computer 10 by hardware and software. The computer 10 includes a program execution environment such as a CPU 11, a RAM 12, and a ROM 13, and can read various programs recorded in the ROM 13 and the HDD (hard disk drive) 14 into the RAM 12 and execute them. In this embodiment, the program includes an OS (not shown), a PRTDRV (printer driver) 20, a scanner DRV (driver) 30a, and the like, and various programs can be activated under the execution of the OS.

  The computer 10 is connected to the scanner 30 and the printer 40 via the USB I / F 15, and is connected to the display 17, the keyboard 16 a, the mouse 16 b, and the scanner 30 via an I / F (not shown). That is, a predetermined image can be output to the display 17 and various input operations can be accepted via the keyboard 16a and the mouse 16b. As described above, the computer 10 can implement the present invention by using hardware generally provided in a general-purpose computer and executing software described later.

  The PRTDRV 20 is a program that generates data for causing the printer 40 to print an image or characters to be printed. In the present embodiment, the PRTDRV 20 includes a module for calibration. That is, the PRTDRV 20 includes an image processing unit 21 and a calibration module 22. The image processing unit 21 acquires image data indicating an image to be printed, and performs predetermined image processing to generate print data.

  That is, the image data is subjected to resolution conversion processing, color conversion processing, halftone processing, and the like, and print data for causing the printer 40 to execute printing is generated. The generated print data is delivered to the printer 40 via the USB I / F 15. The printer 40 performs printing based on the print data as described later. At this time, the image processing unit 21 performs the above-described image processing according to the printing conditions. For example, resolution conversion processing is performed in order to execute printing at the instructed resolution, and color conversion is performed with reference to a color conversion table corresponding to the instructed printing paper.

  In the present embodiment, in order to print an adjustment pattern to be measured at the time of calibration, adjustment pattern data 14a indicating an image of the adjustment pattern and print condition data 14b indicating a print condition set at the time of adjustment are stored in the HDD 14 in advance. It is recorded. That is, the image processing unit 21 refers to the printing condition data 14b and performs image processing on the image data indicated by the adjustment pattern data 14a under the conditions. By outputting this result to the printer 40, the printer 40 prints the adjustment pattern.

  The print condition data 14b only needs to indicate the print condition to be adjusted, and various print conditions that can be set when applying the calibration result can be adopted as the print condition data 14b. For example, when applying a calibration result for each printing paper used at the time of printing, data indicating a plurality of printing paper types is included in the printing condition data 14b, and when a calibration result is applied for each resolution. The print condition data 14b includes data indicating a plurality of print resolutions.

(2-2) Configuration of adjustment pattern:
FIG. 3 is a diagram showing an adjustment pattern employed in the present embodiment. This pattern includes a plurality of rectangular patterns P _{1 to} P ₅ that are long along the longitudinal direction (main scanning direction) of the printing paper. In each of the rectangular patterns P _{1 to} P ₅ , a set value (parameter value) to be calibrated is set. ) Are different (in FIG. 3, the parameters are different as # 1 to # 5). Further, the left and right ends of each of the rectangular patterns P _{1 to} P ₅ are formed by gray (Gr) patches, and are printed by image data for uniformly printing gray of a predetermined brightness.

Violet (V) patches are arranged side by side for each of the gray patches. This patch is printed with image data for uniformly printing violet having a predetermined brightness. In the present embodiment, the gray patch and the violet patch have different brightness, the former having a higher brightness and the latter having a lower brightness. Each of the rectangular patterns P _{1 to} P ₅ includes two gray patches and two violet patches, and four patches are arranged in the main scanning direction as shown in FIG. Also, patches of the same color are arranged in the sub-scanning direction. That is, the patches in the rows A and D arranged in the sub-scanning direction are gray patches, and the patches in the rows B and C are gray patches.

  In addition, gray is the easiest color change for human eyes, and in this sense, gray is a preferred color for analyzing the occurrence of banding noise. Violet is a color in which banding noise is likely to be generated by the printer 40. In this sense, violet is a preferable color for analyzing the occurrence of banding noise. Of course, the color of the patch employed as the adjustment pattern may be any color that is preferable for detecting banding noise, and various other colors can be employed.

  Further, in the present embodiment, as described later, a plurality of colors of ink can be mounted on the printer 40, and all of the plurality of colors are used at least once by a gray patch and a violet patch. That is, any color ink is included in one or both of the gray patch and the violet patch. In this embodiment, patches used for banding noise analysis are not printed between violet patches, but other patches may be printed and used for banding noise detection. In addition, since the ink flying state can be stabilized by continuing to eject ink from the print head, some patches are printed throughout the main scanning direction even when not used for banding noise analysis. Is preferred.

In each of the rectangular patterns P _{1 to} P ₅ , since the set parameter values are different, the occurrence of banding noise may be different for each pattern. In addition, since the degree of banding noise conspicuous varies depending on the color, it can be said that the degree of occurrence of banding noise can be different for each patch. Therefore, if the degree of noise generation is evaluated for each patch, it is possible to determine which parameter value of # 1 to # 5 is desirable. The numerical values shown in FIG. 3 are values for evaluating banding noise, and details will be described later.

  Note that the adjustment pattern in this embodiment is printed for each parameter type. That is, the parameter value for specifying the feed amount is changed, the adjustment pattern for adjusting the feed amount is printed while the other parameter values are fixed, the parameter value for specifying the nozzle used is changed, and the other parameters The adjustment pattern for adjusting the nozzle used is printed with the value fixed.

(2-3) Configuration of calibration module:
As shown in FIG. 2, the calibration module 22 includes a parameter setting unit 22a and a parameter value acquisition unit 22b. The parameters are set based on these, and the occurrence of banding noise is analyzed, and the best parameter value for suppressing noise is obtained from the analysis result.

  The parameter setting unit 22a is a module that changes and sets various parameters for the printer 40 by outputting predetermined control signals via the USB I / F 15. That is, in the present embodiment, an image based on the same adjustment pattern data 14a is printed while changing the parameter value, and the best parameter value is set according to the banding noise state of the obtained printed matter. Therefore, data indicating the parameter type and data indicating the changed value are recorded in the HDD 14 as the parameter data 14c.

  In the present embodiment, the calibration target is the feed amount and the used nozzle, and the feed amount is recorded with data indicating a plurality of feed amounts as changed values. The data indicating the used nozzle is data for designating a set of a plurality of nozzles. FIG. 4 is an explanatory diagram for explaining the parameter data for the nozzles used in the present embodiment. This figure schematically shows the arrangement of nozzles formed on the nozzle surface of a print head 47a mounted on the printer 40. FIG. The print head 47a shown in the figure is reciprocated in the main scanning direction shown in the figure by the main scanning during printing, and the printing paper relatively moves in the sub-scanning direction shown in the figure by paper feed. A plurality of (for example, 180) nozzles Nz for ejecting ink of the same color are arranged in the sub-scanning direction on the nozzle surface of the print head 47a, and this nozzle row corresponds to 7 ink colors. A line is formed.

  The parameter data in the present embodiment is data that specifies that the number of nozzles used in each column is fixed and nozzles at different positions in the sub-scanning direction are used. For example, as in the example shown in the figure, a set of 140 nozzles is used, and a set in which the number of nozzles is shifted by 10 in the sub-scanning direction is used, and nozzles such as parameters # 1 to # 5 are designated. . In any case, the parameter setting unit 22a specifies the calibration target and sets the parameter value. Thereby, the same image data is set to be printed with different parameters.

In the present embodiment, the parameter setting unit 22a sets a parameter to a certain value, the image processing unit 21 prints an adjustment pattern, and the parameter setting unit 22a changes the parameter value to change the image. The rectangular patterns P _{1 to} P ₅ shown in FIG. 3 are printed by repeating the processing by the processing unit 21. In addition, when the adjustment pattern is printed, there are two methods, that is, when only the parameter relating to the feed amount is changed and when only the parameter relating to the nozzle used is changed.

  The scanner DRV 30a is a driver that controls the capturing in the scanner 30. The scanner DRV 30a reads the reading target placed on the document table in accordance with the reading conditions such as the resolution set by the keyboard 16a and the like, and acquires the image data 14d. . In the present embodiment, the image data 14d is data in which an image is expressed by a plurality of images and the color of each image is expressed by gradation values for each color component of RGB (red, green, blue).

  In this embodiment, when the calibration of the printer 40 is performed by the calibration module 22, the scanner DRV 30a is activated, and scanning is performed by setting a reading condition corresponding to the printing condition for printing the adjustment pattern. For example, it is set to a reading resolution preferable for scanning adjustment pattern data printed under each printing condition. That is, in order to increase the accuracy of detecting banding noise, it is preferable to perform high-resolution reading. However, if the resolution is excessively high, the amount of data is excessively increased and the processing speed is decreased.

  If the reading resolution is close to the printing resolution (for example, within a range of ± 10 dpi), moire may occur. Therefore, it is preferable to set a preferable reading resolution in consideration of accuracy and processing speed, or to set the reading resolution to prevent the occurrence of moire. When reading is performed with a CCD, one pixel is often generated from the reading results of a plurality of CCDs. However, one pixel is generated from an integer number or (integer / 2) number of CCDs. Is preferred. For example, a configuration in which the reading resolution is set so that image data for two pixels is generated from five CCDs may be employed.

  In the above example, when analyzing the image data 14d, a configuration for accurately grasping the calibration target is adopted. That is, in the adjustment pattern shown in FIG. 3, information indicating a change target (feed amount or used nozzle in this example) when the adjustment pattern is printed is described at the upper left of the adjustment pattern. More specifically, these pieces of information are indicated by the position and number of the character “I”, and the scanner DRV 30a refers to the portion corresponding to these characters in the image data 14d to acquire the calibration target. Information indicating the calibration target is transferred to the calibration module 22 and is referred to when setting the best parameter value. Further, in the present embodiment, in order to eliminate reading variations by the scanner 30, a plurality of scans are performed as described later.

  The parameter value acquisition unit 22b extracts the patch for each color based on the image data 14d read as described above, and calculates a banding noise value for evaluating the degree of occurrence of banding noise in each patch. If the banding noise value is obtained, add the banding noise value of each patch for each parameter value, or compare the banding noise values of the patches existing on the left and right in the main scanning direction. It can be determined whether it exists.

  That is, the calibration target in the present embodiment is the feed amount and the used nozzle, and the calibration target parameter cannot be changed within one main scan when the printer 40 is driven. Therefore, in the present embodiment, different parameters cannot be set on the left and right sides of the main scan, and parameters that suppress the banding noise as a whole should be set in view of the banding noise values on the left and right sides of the main scan. . Also, it is impossible to set different parameters for each color, and parameters for which banding noise is suppressed as a whole in each color patch should be set.

For example, in the rectangular patterns P _{1 to} P ₅ shown in FIG. 3, even if patches in different rectangular patterns on the left and right of the main scanning have the best banding noise value, parameter # 1 and main scanning It is not possible to drive the printer 40 by setting parameters # 2 on the right. Therefore, the parameter value acquisition unit 22b compares the banding noise for the left and right of the main scanning and for each color, and selects the parameter with the lowest banding noise.

  When the best parameter value is acquired, the parameter value acquisition unit 22b passes the value to the parameter setting unit 22a. Then, the parameter setting unit 22a sets the best parameter value for the printer 40 via the USB I / F 15. As a result, in the printer 40, printing can be executed using the best parameter value, and printing can be executed in a state where generation of banding noise is suppressed. Of course, in the present embodiment, the above processing is performed for each of the feed amount and the used nozzle.

  In this process, it is only necessary to obtain the best parameter value by evaluating the degree of noise generation in each patch, and various processes can be employed. Needless to say, when adjusting each calibration target, the parameter fluctuation range may be increased and coarsely adjusted for the first time, and after the coarse adjustment, the fluctuation range may be reduced and adjustment may be performed. An example of this process will be described later.

(2-4) Printer configuration:
FIG. 5 is a block diagram showing functions of the printer 40 by hardware and software. The printer 40 includes a program execution environment such as a CPU 41, a RAM 42, a ROM 43, and an EEPROM 44, and controls each unit via the I / Fs 45a to 45d according to a predetermined program. The USB I / F 45a is an I / F that acquires control data for setting the print data, the feed amount, and the nozzles used that are output from the computer 10.

  A carriage mechanism 46, a print head unit 47, and a paper feed mechanism 48 are connected to the I / Fs 45b to 45d, respectively. The print head unit 47 includes a mechanism for supplying the ink filled in the print head 47a and the ink cartridge to the ink chamber, and the like, and a piezo element for discharging ink to each ink nozzle in the print head 47a. Is provided. Each piezo element is controlled via the I / F 45c. As a result of this control, ink is recorded or not recorded for each pixel. Of course, this configuration is merely an example, and various other configurations such as a configuration for controlling ejection / non-ejection of ink by bubbles and a configuration for controlling the ejection amount of ink droplets in several stages can be employed. .

  The carriage mechanism 46 includes the print head unit 47 and includes a portion that can be driven in the main scanning direction (substantially perpendicular to the paper feed direction). The print head is synchronized with the ejection / non-ejection of the ink under the control of the CPU 41. The unit 47 is main-scanned. The paper feed mechanism 48 is provided with a mechanism for conveying the printing paper accumulated in an accumulation unit (not shown) one by one, and this mechanism conveys the printing paper to a site for recording ink. Then, sub-scanning is performed in synchronization with the ink ejection / non-ejection.

  In the printer 40 having such a configuration, in the present embodiment, processing by the print execution unit 41a and the parameter setting unit 41b can be executed under the control of the CPU 41 and the like. The print execution unit 41a acquires print data via the USB I / F 15, and executes printing by driving each unit based on the print data. That is, since the print data indicates ink recording / non-recording for each pixel, the print head unit 47, the carriage mechanism 46, and the paper feed mechanism 48 are controlled so that ink is recorded according to this data. To do. At this time, the paper feed mechanism 48 is controlled so that the print paper is fed at the set feed amount by referring to the feed amount set value and the used nozzle set value recorded in the EEPROM 44, The print head unit 47 and the carriage mechanism 46 are controlled so that ink droplets are ejected using the used nozzles.

The parameter setting unit 41 b is a module that records the feed amount setting value and the used nozzle setting value in the EEPROM 44. The parameter setting unit 41 b acquires the parameter setting value transmitted from the computer 10 via the USB I / F 15 and records it in the EEPROM 44. To do. Therefore, when the adjustment pattern data is printed as described above, the parameter set value is written to the EEPROM 44 each time the rectangular patterns P _{1 to} P ₅ are printed, and each rectangular pattern P _{1 to} P ₅ has a different parameter. Control to be printed. After the best parameter is extracted, the best parameter is written into the EEPROM 44, and thereafter, the printer 40 is controlled to print using this parameter.

(3) Calibration process:
6 to 9 are flowcharts showing the procedure of the calibration process in the present embodiment. The schematic flow of the calibration process is as shown in FIG. 6. First, in step S100, the paper feed amount is changed and the adjustment pattern is printed.

(3-1) Adjustment pattern printing process:
FIG. 7 is a detailed flowchart showing the adjustment pattern printing process. In step S200, the counter n corresponding to the parameter number is initialized to “1”. In step S210, the parameter setting unit 22a refers to the parameter data 14c and performs setting for the printer 40. That is, referring to the parameter data 14c, the set value of the parameter number n is acquired, the control data is transmitted to the printer 40, and the set value is stored in the EEPROM 44. The flowchart shown in FIG. 7 is a common flow for changing the feed amount and changing the used nozzle. Of course, when changing the feed amount, the feed amount parameter n is set in the printer in step S210. If the used nozzle is changed, the parameter n of the used nozzle is set in the printer in step S210.

  In step S220, the image processing unit 21 acquires the adjustment pattern data 14a, and generates print data for printing under one of the printing conditions instructed in the printing condition data 14b in step S230. The generated print data is output to the printer 40 in step S240. As a result, the adjustment pattern (one of the rectangular patterns) is printed with the parameter to be calibrated set to a certain parameter n.

  In step S250, it is determined whether or not the counter n has exceeded a predetermined parameter number α (α = 5 in the example shown in FIG. 3). In step S250, it is determined that the counter n has exceeded the parameter number α. If not, the counter n is incremented at step S260, and the processing after step S210 is repeated. If it is determined in step S250 that the counter n has exceeded the parameter number α, printing of the adjustment pattern is completed while changing the parameter within a predetermined range, and the process returns to the process of FIG. .

(3-2) Scan processing:
When returning to the processing of FIG. 6, the printed adjustment pattern is scanned in step S <b> 110 and the image data is recorded in the HDD 14. FIG. 8 is a detailed flowchart showing the adjustment pattern scanning process. In step S300, the adjustment pattern printed in the flow shown in FIG. 7 is placed on the document table of the scanner 30. In step S310, the scanner DRV 30a controls the scanner 30 to perform a predetermined number of dummy scans in order to stabilize the light source that projects the document. Of course, it is only necessary to stabilize the amount of light from the light source here, so a standard preview may be implemented as a function of the scanner DRV 30a, or a predetermined time may be allowed to elapse while the light source is turned on. Various configurations such as turning on the light source can be employed.

  In step S320, the scanner DRV 30a sets a reading resolution suitable for the printing conditions when the adjustment pattern is printed. In step S330, scanning is performed twice based on the reading resolution. In step S340, image data based on the results of the two scans is recorded in the HDD 14, and the process returns to the process shown in FIG. In this scan, in order to reduce the variation in the measurement variation of the scan as much as possible, the average of the banding noise values calculated by each of the two scans is calculated. Of course, it is only necessary to suppress variation in measurement here, and the number of scans is not limited to two. If the scan result is sufficiently stabilized by the dummy scan in step S310, the scan may be performed once. However, it is preferable that the scan is performed twice or more, for example, when the scan is performed by a so-called consumer scanner.

  After returning to the processing of FIG. 6, a banding noise value is acquired in step S120 based on the image data 14d recorded in the HDD 14 in step S340. In FIG. 3, a numerical value is added to each patch. This numerical value is an example of a banding noise value. An example of processing for acquiring the banding noise value will be described later. When the banding noise value is acquired, it is stored in the RAM 12, and the best value extraction process is performed in step S130.

(3-3) Best value extraction process:
FIG. 9 is a detailed flowchart showing a process for selecting the best parameter. The parameter value acquisition unit 22b adds the banding noise values for each parameter in step S400. That is, the banding noise values are added for a certain parameter in step S400, and step S400 is repeated until it is determined in step S405 that the processing has been performed for all parameters. For example, in the example shown in FIG. 3, the banding noise values calculated for the parameter # 1 are “25, 22, 26, 30” for the columns A to D, respectively, and these are added together to obtain the value “103”. Is calculated. The similarly calculated values for parameters # 2 to # 5 are “83, 72, 92, 104”.

  In step S410, the minimum value is extracted from the total values for each parameter calculated as described above. In the present embodiment, the banding noise value is assumed so that the value increases as the frequency and intensity of banding increase. Therefore, it can be said that by extracting a value having the minimum total value, a state in which banding does not occur as much as possible is extracted in printing each patch. That is, the occurrence of banding noise differs in each of the plurality of patches, and it can be said that the smallest banding noise is the smallest banding noise when the patches are compared for each column.

  However, since it is necessary to set a certain parameter for the printer 40 and perform printing, when a patch having a minimum banding noise value exists in different parameters (for example, parameter # 3 in column A and parameter # 3 in column B). Even if parameter # 2 is the minimum), one of the parameters must be selected. Therefore, in the present embodiment, the best parameter is selected by adding the banding noise value for each parameter and comparing the total value. As a result, the best parameter (the lowest frequency of banding noise as a whole) can be extracted.

  Furthermore, in this embodiment, in order to perform the best setting more reliably, it is determined whether or not it is a defective aircraft. That is, even if the best parameter is selected as described above, in rare cases, there may be a defective aircraft that is insufficient to complete the calibration. For example, if the banding noise values for all the parameters exceed the allowable value, it cannot be said that the calibration is completed even if the best parameter is selected with the minimum total value. Further, if there is a large difference in banding noise values at both ends of the main scanning even if the total value is the smallest, it is considered that the main scanning direction and the sub-scanning direction are inclined at right angles. Therefore, even in this case, the calibration should not be completed.

Therefore, in the present embodiment, it is determined in step S415 whether or not the banding noise value at the best parameter is equal to or less than a predetermined threshold value. That is, the threshold value T ₁ for the Gr patch and the threshold value ₂ for the V patch are set in advance and recorded in the HDD 14, and the banding noise values of the two Gr patches at the best parameters are compared with the threshold value ₁ . Compare the banding noise value with threshold ₂ . Each of the threshold values ₁ and ₂ is a banding noise value corresponding to the limit value of the allowable banding noise.

If it is determined in step S415 that the banding noise value at the best parameter is equal to or smaller than the threshold value, the difference between the banding noise values of the patches at both ends is calculated in step S420. At this time, the same color, that is, the difference between the Gr patches and between the V patches is calculated. In step S425, it is determined whether or not the difference is a predetermined threshold value ₃ or less. Here, the threshold ₃ is an allowable value as a difference between banding noise values in the patches at both ends, and is determined in advance.

If it is determined in step S425 that the difference is equal to or smaller than the predetermined threshold ₃ , banding noise can be suppressed by the best parameter extracted in step S410, and it may be appropriate as a setting value for the printer 40. It has been confirmed. Therefore, the parameter setting unit 22a sets the parameter in the printer 40 in step S430. When the process of step S430 is completed, the process corresponding to step S130 in FIG. 6 is completed, and as a result of this process, the paper feed amount in which the banding noise is minimized is set in the printer 40.

In the present embodiment, after the adjustment of the paper feed amount, adjustment of the used nozzle is also performed, and the process for adjusting the used nozzle is performed in steps S140 to S170 of FIG. carry out. This processing is the same as the processing shown in FIGS. 7 to 9 except that the processing target is the nozzle to be used. That is, the parameter value is changed as shown in FIG. 4, the adjustment pattern is printed, the banding noise value is analyzed, and the setting is made so as to be the best parameter. As a result of this processing, printing is set to be performed using a set of nozzles in which banding noise is most suppressed. Of course, the change in the feed amount has a greater effect on the banding noise, so the values of the above threshold ₁ to threshold _3, etc. are different values for the paper feed amount adjustment and the adjustment of the nozzle used. It is a big value.

If it is not determined in step S415 that the banding noise value at the best parameter is less than or equal to a predetermined threshold value, and if the difference is not determined to be less than or equal to the predetermined threshold value _{3 in} step S425, a response is encouraged. Perform the process. In the present embodiment, when the feed amount having a large influence on the banding noise is the processing target parameter, a re-investigation is prompted, and when the used nozzle having a small influence on the banding noise is the processing target parameter, the printed adjustment The user is prompted to select the best pattern from the patterns.

  That is, since the flow shown in FIG. 9 is applied to step S130 and step S170, the type of parameter to be processed is determined in step S435. If it is determined in step S435 that the parameter type is a parameter for specifying the feed amount, the display 17 is controlled in step S440 to display that the printer 40 is defective. When this display is made, manual adjustment such as carriage height adjustment is performed. For this reason, the process by the calibration module 22 is complete | finished.

  If it is determined in step S435 that the parameter type is a parameter for specifying the nozzle to be used, the display 17 is controlled in step S445 to display that the banding noise value exceeds the threshold value. . Further, the user selects and inputs the most preferable parameter value with reference to the displayed and printed adjustment pattern. In step S450, the parameter value input via the keyboard 16a, the mouse 16b, or the like. Accept. In step S455, the parameter setting unit 22a sets the parameter in the printer 40.

  That is, before setting the best parameter value for the parameter for specifying the nozzle to be used, the parameter value for specifying the feed amount is set to the best parameter value, and as a result, no large banding noise occurs. Have been adjusted so that. Therefore, in the present embodiment, it is assumed that a parameter value for suppressing noise can be obtained even if the banding noise value exceeds the threshold value by changing the parameter for specifying the nozzle to be used. To decide.

  Of course, this process is merely an example, and various other processes can be employed. For example, in order to perform the adjustment again, the parameters for specifying the nozzles to be used may be further changed to print the adjustment pattern, and the same processing may be performed. Further, the banding noise value calculated for each parameter may be displayed on the display 17 for reference at the time of display in step S445.

(4) Banding noise value calculation example:
FIG. 10 is a diagram for explaining an example of processing for calculating a banding noise value. Typical banding noise is an unintentional linear part parallel to the main scanning direction in the print result, and different colors (bright or dark parts) in the main scanning direction compared to the surrounding image. Generated by being continuous. Therefore, banding noise can be analyzed by extracting brightness information from the distribution information of the print result. In addition, since banding noise is generated with some periodicity in the sub-scanning direction, if the brightness change in the sub-scanning direction is Fourier-transformed, an image in which banding noise is generated has a power spectrum at a predetermined spatial frequency. The value is thought to increase.

Therefore, if the brightness change in the sub-scanning direction is extracted from the patch distribution information and a one-dimensional FFT is used, it is possible to evaluate the degree of occurrence of banding noise that occurs periodically in the sub-scanning direction. In the upper part of FIG. 10, the change in the lightness of the patch is shown with the horizontal axis being the position (unit 0.1 mm) and the vertical axis being the lightness L ^* . That is, the brightness value for each position in the sub-scanning direction is plotted. If such a one-dimensional brightness change can be obtained, a power spectrum as shown in the lower part of FIG. 10 can be obtained by performing a Fourier transform on the data by FFT or the like.

  In this power spectrum, if the brightness change indicating some periodicity is large, the spectrum value has a peak shape. Therefore, if banding noise occurs, the number of peaks in the power spectrum and the spectrum value at the peak increase. Therefore, if the power spectrum value is integrated, the degree of noise generation can be evaluated. Therefore, if the FFT result as shown in the lower part of FIG. 10 is integrated in the spatial frequency direction, a banding noise value for evaluating the banding noise of the patch can be obtained. The banding noise value can be acquired.

  In order to acquire the banding noise value, various processes are possible, and even in the above-described process, various devices can be added to evaluate noise with higher accuracy. For example, the patch may be divided into a plurality of areas that are long in the sub-scanning direction, and banding noise values may be acquired by acquiring one-dimensional brightness distribution information for each of the divided areas. If distribution information or a banding noise value is acquired for each divided region, a unique region different from other regions can be extracted by comparing them with each divided region. Since it is considered that this area includes noise that is not included in other areas, banding noise is generated with high accuracy if information on this area is removed in advance and banding noise is evaluated only in the remaining area. The degree can be evaluated.

  In addition, if the analysis is performed by dividing the patch into a plurality of regions, the period of noise generated in the sub-scanning direction can be clearly realized, and high-precision analysis is possible. That is, if the printing paper is tilted when the patch distribution information is read by an optical reader or the like, the sub-scanning direction at the time of reading differs from the sub-scanning direction at the time of printing the patch. Therefore, in the sub-scanning direction of the read result, banding noise exists over a width wider than the banding noise width on the patch. In this situation, if the lightness is averaged in the main scanning direction at the time of reading for the entire patch, it becomes difficult to understand the lightness change caused by noise periodically generated in the subscanning direction at the time of printing.

  However, if averaging is performed for each divided area, the length of each divided area in the main scanning direction is shorter than the entire patch, so that the banding noise exists in the sub-scanning direction due to the inclination. Becomes shorter. As a result, the period of banding noise can be reliably detected. In the analysis by Fourier transform, it is impossible to analyze with high accuracy unless the periodicity of noise is reliably detected, but if divided as described above, a Fourier transform result that reliably reflects the periodicity can be obtained. It can be analyzed accurately.

Moreover, you may perform correction | amendment for making noise appear more prominent with respect to the said distribution information. For example, in the case of a high-lightness patch (Gr in FIG. 3), when the lightness L ^* is smaller than a predetermined reference, the difference between the lightness and the reference is further increased under the insight that the low-lightness line is likely to be banding noise. Make corrections to emphasize. Similarly, in the low-lightness patch (V in FIG. 3), when the lightness L ^* is larger than a predetermined reference, the difference between the lightness and the reference is further increased with the insight that the high-lightness line is likely to be banding noise. Make corrections to emphasize.

  The predetermined standard may be a typical brightness value of each patch. For example, a change tendency value of the brightness L can be adopted. That is, the change in the lightness L reflects the banding noise, but the banding noise is detected based on whether or not the lightness L has changed compared to the surrounding images. A value indicating the change tendency is adopted. Since the patches in this embodiment are printed with print data for printing in a uniform color, the reference brightness should be almost constant, but in reality, a change tendency (low frequency undulation) is observed. It is done.

  Therefore, it is preferable to calculate the change tendency value by applying a low-pass filter to the change in brightness with respect to the position. For example, the change tendency value of a certain point can be calculated by acquiring brightness values in the range of 2 mm in the front and rear direction in the sub-scanning direction (pixels corresponding thereto) and averaging the points. As another example, a change tendency value of a point is obtained by obtaining a brightness value in a range of 2 mm in front and back in the sub-scanning direction around the point (corresponding to a pixel), and obtaining a median value by a median filter or the like. Can also be calculated by, for example, approximating. Of course, the change tendency may be a value indicating the tendency of the overall change in brightness, and the range for calculating the average is not limited to 2 mm, and can be calculated by various other methods.

  Furthermore, when calculating the banding noise value, the background of the power spectrum may be removed in advance. That is, since banding noise is periodically generated as described above, in the power spectrum as shown in the lower part of FIG. 10, it is considered that each peak is a spectrum caused by banding noise. Therefore, if the background that exists over the entire spatial frequency is calculated and removed from the spectrum value, the banding noise can be evaluated more accurately. The background can be calculated by various methods. For example, the background can be calculated by applying a median filter to the power spectrum value and fitting the obtained result with a sixth-order function.

  Furthermore, the banding noise value may be calculated in consideration of the visual characteristics of the human eye. That is, since there exist spatial frequencies that are easy to recognize for human vision and spatial frequencies that cannot be recognized, filter processing based on visual characteristics is performed in order to more reliably analyze banding noise perceived by humans. As the filter based on visual characteristics, various filters reflecting human visual characteristics can be adopted. For example, a visual transfer function (VTF) may be used, or only a fixed spatial frequency (for example, 0). .2 mm to 4 mm) may be left.

  Further, when different emphasis is performed for each color of the patch as described above, the banding noise value may be normalized in advance when evaluating the sum of the banding noise. For example, in the pattern shown in FIG. 3, the banding noise value for the patch of the same color is acquired for each column, and the process of dividing by the minimum value is performed, thereby normalizing. In the column A in FIG. 9, the minimum banding noise value is the value 15 of parameter # 3, and the banding noise values “25, 21, 15, 22, 28” of parameters # 1 to # 5 are set to “15”. Normalize by dividing by.

(5) Other embodiments:
The above embodiment is an example for realizing the present invention, and it is possible to adopt other configurations and processing procedures. For example, the present invention may be applied to a laser printer instead of an ink jet printer. In this case, as factors for generating banding noise, attention can be paid to various factors such as laser output as well as the paper feed amount. Also, the arrangement of the nozzles is not limited to the arrangement shown in FIG. 4, and two rows of nozzles may be formed for one color of ink, and the number of ink colors is not limited to seven.

  Furthermore, when changing the use nozzle, the structure which fixes the number of use nozzles as shown in FIG. 4 is not necessarily required. In this case, a set of a plurality of nozzles obtained by changing the number of used nozzles is specified by the parameter data 14c, and these are appropriately changed by the setting in the parameter setting unit 22a to print the adjustment pattern. Regardless of how the number of nozzles used and the position of the nozzles used are changed, a parameter that reliably suppresses the banding noise can be obtained by calculating the banding noise value in the adjustment pattern described above.

  Further, the adjustment pattern is not limited to the above-described pattern. For example, patches composed only of ink droplets ejected from each of a plurality of ink colors may be arranged in the main scanning direction. As a result, it is possible to detect whether banding noise can be generated individually for each color. Of course, for example, a gray patch may be added at a symmetrical position at the end in the main scanning direction with respect to this pattern, and various configurations can be adopted. In addition, it is not essential to print a plurality of patches according to each parameter in the sense that a factor that easily affects noise is adjusted first.

  Furthermore, the types of parameters are not limited to the parameters for specifying the feed amount and the parameters for specifying the nozzles to be used as described above. For example, it is possible to employ a parameter that specifies the feed speed when the printing paper is conveyed in the printer. In this case, the setting value of the feed speed can be stored in the EEPROM 44 shown in FIG. 5, and the parameter setting unit 41b of the CPU 41 sets the feed speed in the paper feed mechanism 48 with reference to the set value of the feed speed. To do.

  Further, a parameter for specifying a voltage to be applied to the piezo element when ink is ejected from the nozzle in the print head unit 47 may be employed. That is, by adjusting this voltage, the ink weight per droplet of ejected ink can be adjusted. Therefore, the set value of the applied voltage can be stored in the EEPROM 44 shown in FIG. 5, and the parameter setting unit 41b of the CPU 41 refers to the set value of the applied voltage to drive the piezoelectric element drive voltage in the print head unit 47. Set.

  Further, a configuration may be adopted in which a printing paper suction mechanism (not shown) is formed on the platen of the printer 40, and the negative pressure (suction force) applied to the printing paper from the suction mechanism is variable depending on parameters. In this case, the setting value of the suction force can be stored in the EEPROM 44 shown in FIG. 5, and the parameter setting unit 41b of the CPU 41 sets the suction force in a suction mechanism (not shown) with reference to the setting value of the suction force. To do.

  Furthermore, an option may be provided in the PRTDRV20, and an option that suppresses noise most may be selected from each option by specifying the option by a parameter. Of course, also in this case, the calibration can be performed reliably and efficiently by adjusting the options that greatly affect the noise.

  An example of processing that can provide options is color conversion processing. That is, in the color conversion process, a profile is referred to, and a variety of profiles can be created according to printing conditions, creation ideas, and the like. Therefore, a plurality of profiles are created and recorded in the HDD 14. These profiles are specified by parameters, and the specified profile is referred to when the image processing unit 21 performs color conversion processing.

  In addition, in the printer 40 configured to be capable of ejecting a plurality of heavy ink droplets (for example, large, medium, and small) with one dot, a large profile is referred with reference to another profile (referred to as a large, medium, and small distribution profile) after the color conversion. The gradation value of each medium / small dot is determined. This large / medium / small distribution profile can also be created in a wide variety of profiles depending on the printing conditions and the concept of creation. Therefore, a plurality of large, medium, and small distribution profiles are created and recorded in the HDD 14. These large, medium, and small distribution profiles are specified by parameters, and the specified large, medium, and small distribution profiles are referred to when the image processing unit 21 performs large, medium, and small distributions.

  Further, in a normal printer, halftone processing is performed. Since various algorithms exist in this halftone processing, it is possible to configure so that an algorithm can be selected. In this case, the program is recorded in the HDD 14 so that a plurality of halftone algorithms can be executed. These halftone algorithms are specified by parameters, and when the image processing unit 21 executes the halftone algorithm, the specified halftone algorithm program is executed.

It is explanatory drawing for demonstrating the outline of this invention. It is a block diagram which shows the structure of a computer. It is a figure which shows the pattern for adjustment. It is explanatory drawing explaining the parameter data about a use nozzle. FIG. 2 is a block diagram illustrating a configuration of a printer. It is a schematic flowchart which shows the procedure of a calibration process. It is a flowchart which shows the printing process of the pattern for adjustment. It is a flowchart which shows a scanning process. It is a flowchart which shows the selection process of the best parameter. It is explanatory drawing of the process which calculates a banding noise value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Computer, 14a ... Adjustment pattern data, 14b ... Printing condition data, 14c ... Parameter data, 14d ... Image data, 21 ... Image processing part, 22 ... Calibration module, 22a ... Parameter setting part, 22b ... Parameter value acquisition , 30 ... scanner, 40 ... printer, 41a ... print execution unit, 41b ... parameter setting unit

Claims (17)

Printing means for printing a patch by setting one type of parameter to a printing apparatus that is driven by setting at least two or more types of parameters;
Parameter value acquisition means for acquiring distribution information indicating the distribution of the recording material for the patch, and acquiring a parameter value to be set as the parameter of the sequentially changed type in order to suppress noise based on the acquired distribution information; Comprising
When acquiring the parameter value to be set by executing the processing by the printing unit and the parameter value acquisition unit at least twice, the parameter of the type that has a relatively large influence on the degree of noise generation is relatively small. An optimum value acquisition apparatus characterized in that processing is performed before parameters of an affecting type. 2. The optimum value acquisition apparatus according to claim 1, wherein the parameter value is a setting value that affects a position in a sub-scanning direction of a recording material to be recorded by a printing apparatus. The two or more types of parameters are a parameter for specifying a feed amount when sending a recording medium in the printing apparatus, and a parameter for specifying a use nozzle among a plurality of nozzles formed on the print head of the printing apparatus. The optimum value acquiring apparatus according to claim 1, wherein the optimum value acquiring apparatus includes: The two or more types of parameters are a parameter for specifying the feed speed when the recording medium is fed in the printing apparatus, a parameter for specifying the amount of recording material to be recorded per unit dot in the printing apparatus, and a recording in the printing apparatus. The optimal value acquisition apparatus according to any one of claims 1 to 3, including any one or a combination with a parameter for specifying a suction force when the medium is sucked to the platen. The two or more types of parameters are variable for specifying a profile to be referred to when converting the color system of image data representing an image to be printed and the amount of recording material per unit dot in the printing apparatus. A parameter for specifying a profile to be referred to when determining the amount of the recording material, and a parameter for specifying an algorithm for changing the number of gradations per unit pixel in image data indicating an image to be printed. The optimal value acquisition apparatus according to any one of claims 1 to 4, further comprising any combination or combination with a meter. 6. The optimum value acquisition apparatus according to claim 1, wherein the patch includes a color in which the noise is easily recognized by human eyes. The optimal value acquisition apparatus according to any one of claims 1 to 6, wherein the patch includes a color in which the noise is frequently generated in a printing apparatus that prints the patch. 8. The optimum value acquisition apparatus according to claim 1, wherein the patch includes recording materials of all colors that can be used in a printing apparatus. The parameter value acquisition means acquires a value indicating the degree of noise generation for each patch based on the distribution characteristic value indicating the characteristic of the recording material distribution, and adds the value indicating the noise generation level for each parameter value. 9. The optimum value acquisition apparatus according to claim 1, wherein a parameter value for suppressing the noise is acquired based on the obtained value. The parameter value acquisition means determines whether or not a value indicating the degree of occurrence of noise satisfies a predetermined criterion, and a parameter of a type that has a relatively large influence on the degree of occurrence of noise satisfies the criterion. If not satisfied, a message indicating that the printing device is defective is displayed on a predetermined display device, and if the parameter of a type that has a relatively small effect on the degree of noise generation does not satisfy the standard, the patch is printed. 10. The optimum value acquisition apparatus according to claim 1, wherein an input designating any one of the parameter values set at the time of receiving is received via a predetermined input device. The distribution information is acquired by an optical reading device, and prior to acquisition of the distribution information, a preview scan or a process of causing a light source to emit light is performed for light source stabilization. The optimal value acquisition device according to crab. 12. A calibration apparatus comprising: parameter setting means for setting the printing apparatus to be driven with the parameter value acquired by the optimum value acquisition apparatus according to any one of claims 1 to 11. A first printing means for sequentially setting a variable first parameter in the printing apparatus to a plurality of parameter values and printing a patch for each parameter value;
First parameter value acquisition means for acquiring distribution information indicating the distribution of the recording material for the patch, and acquiring a parameter value to be set as the first parameter in order to suppress noise based on the acquired distribution information;
For the variable parameters in the printing apparatus, the first parameter is set to the acquired parameter value, the second parameter different from the first parameter is sequentially set to a plurality of parameter values, and a patch is printed for each parameter value. Two printing means;
Second parameter value acquisition means for acquiring distribution information indicating the distribution of the recording material for the patch and acquiring a parameter value to be set as the second parameter in order to suppress noise based on the acquired distribution information; An optimum value acquisition device comprising: An optimal value acquisition program for acquiring the optimal parameter value when driving a printing apparatus,
A printing function for printing patches by setting at least two types of parameters while sequentially changing one type of parameter to a printing apparatus that is driven and set;
A parameter value acquisition function for acquiring distribution information indicating the distribution of the recording material for the patch, and acquiring a parameter value to be set as the parameter of the sequentially changed type in order to suppress noise based on the acquired distribution information; In realizing the above on a computer,
When acquiring the parameter value to be set by executing the processing by the printing function and the parameter value acquiring function at least twice, the parameter of the type that has a relatively large influence on the noise generation level is relatively small. An optimum value acquisition program characterized in that processing is performed before parameters of an affecting type. 15. A calibration program for causing a computer to realize a parameter setting function for setting the printer to drive with the parameter value acquired by the optimum value acquisition program according to claim 14. An optimal value acquisition method for acquiring an optimal parameter value when driving a printing apparatus,
A printing process in which at least two types of parameters are set and driven, and a patch is printed by setting one type of parameters while sequentially changing the parameters;
A parameter value acquisition step of acquiring distribution information indicating the distribution of the recording material for the patch, and acquiring a parameter value to be set as the parameter of the type that has been sequentially changed in order to suppress noise based on the acquired distribution information; Comprising
When acquiring the parameter value to be set by performing the processing by the printing process and the parameter value acquisition process at least twice, the parameter of the type that has a relatively large influence on the degree of noise generation is relatively small. A method for obtaining an optimum value, characterized in that the processing is performed prior to the parameter of the affecting type. 17. A calibration method, comprising: a parameter setting step for setting the printing apparatus to be driven with the parameter value acquired by the optimum value acquisition method according to claim 16.

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