JP4640246B2 - Calibration support device - Google Patents

Description

  The present invention relates to a calibration support apparatus that supports calibration work in an image forming apparatus such as a color printer.

  In an image forming apparatus such as a color printer, it is desirable to form the same image on a medium such as paper if the given image data is the same. However, in reality, not only long-term fluctuations due to deterioration of members related to image formation such as a developing unit and a drum, but density fluctuations may occur for each page to be formed.

Patent Document 1 discloses a technique for optimizing gradation characteristics at the time of use so that an external correction request can be issued.
JP-A-8-251414

  As described above, in the technology related to the conventional color printer and the like, as shown in Patent Document 1, consideration is given to the gradation characteristics at the time of use. However, no consideration has been given to whether or not a calibration sheet used in a calibration process for adjusting an image forming apparatus such as a color printer to a standard state is subjected to such a density fluctuation for each page. For this reason, the calibration is performed based on the calibration sheet output in a state where the density fluctuation is large, and the calibration accuracy may be lowered.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a calibration support apparatus capable of maintaining and improving the accuracy of calibration in consideration of density fluctuation between pages in a calibration sheet. I will.

  The present invention for solving the problems of the above-described conventional example is a calibration support apparatus, and causes a calibration target image forming apparatus to form a plurality of calibration sheets including a plurality of color patches. Forming instruction means and at least a part of the color patches formed on the plurality of calibration sheets as a variation confirmation patch group, the density patch color density formed on each calibration sheet based on the variation confirmation patch group; Using the fluctuation estimating means for estimating the time fluctuation and the estimated time fluctuation of the inter-page density, the number of pages to be formed until a calibration sheet that satisfies a predetermined condition is formed is estimated as the required number of pages. Means for storing, the information on the required number of pages is formed of a calibration sheet It is characterized by being used to sense.

  Here, the variation confirmation patch group may be formed separately from the calibration patch group used for calibration, and the variation confirmation patch group is used by the image forming apparatus to be calibrated for image formation. You may form separately for every coloring material.

  Another embodiment of the present invention is a calibration support method, wherein a plurality of calibration sheets including a plurality of color patches are formed on an image forming apparatus to be calibrated, and the plurality of calibration sheets is formed. Using at least a part of the color patches formed above as a variation confirmation patch group, the variation of the color patch density formed on each calibration sheet is estimated based on the variation confirmation patch group, and the estimated page The number of pages to be formed until a calibration sheet that satisfies a predetermined condition is formed using the time variation of the inter-density, and stored as the required number of pages. It is characterized by being used for a calibration sheet forming process. This calibration support method may be realized using a computer.

  According to another aspect of the present invention, there is provided a program for causing a computer to form a plurality of calibration sheets including a plurality of color patches for an image forming apparatus to be calibrated. A procedure for estimating at least a part of the color patches formed on the calibration sheet as a variation confirmation patch group, and estimating a temporal variation in the density of the color patch formed on each calibration sheet based on the variation confirmation patch group; Using the estimated time variation of inter-page density, estimating the number of pages to be formed until a calibration sheet that satisfies a predetermined condition is formed, and storing the number of pages as a necessary page, Information on the required number of pages is used for the calibration sheet formation process. .

  Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a calibration support apparatus 1 according to an embodiment of the present invention is connected to a printer 2 as an image forming apparatus, for example. As shown in FIG. 1, the calibration support apparatus 1 according to the present embodiment includes a control unit 11, a storage unit 12, an operation unit 13, a display unit 14, an interface unit 15, and a reading unit 16.

  The control unit 11 is a program control device such as a CPU, and operates according to a program stored in the storage unit 12. In response to an instruction to calibrate the printer 2, the control unit 11 causes the printer 2 to output a plurality of calibration sheets.

  In addition, the control unit 11 receives the input of the result of reading at least a part of the color patch group previously determined as the variation confirmation patch group from among the color patches on the calibration sheet from the reading unit 16, and performs each calibration. Check the time change of the density of the color patch on the sheet, and the number of calibration sheets formed until the predetermined condition for judging whether or not it can be used for calibration is determined from the state of the time change. Perform the estimation process. Details of the processing of these control units 11 will be described later.

  The storage unit 12 includes a storage element such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The storage unit 12 stores a program executed by the control unit 11. Further, the storage unit 12 also operates as a work memory for the control unit 11.

  The operation unit 13 is a mouse, a keyboard, or the like, and outputs the content of the user's instruction operation to the control unit 11. The display unit 14 is a display or the like, and presents information to the user according to an instruction input from the control unit 11.

  The interface unit 15 is an interface such as a USB (Universal Serial Bus) connected to the printer 2, and transmits and outputs instructions, image data, and the like input from the control unit 11 to the printer 2. The reading unit 16 is a scanner or the like that reads a color patch on a calibration sheet formed by the printer 2, and outputs image data obtained by reading to the control unit 11. The reading unit 16 may be a colorimeter, a flat bed scanner, a handy scanner, or the like.

  Here, the content of the process of the control part 11 is demonstrated. The control unit 11 receives an instruction from the operation unit 13 to start calibration of the printer 2 as an instruction operation by the user, and serves as a basis for a calibration sheet for the printer 2 to be calibrated. The image data is transmitted, and a forming instruction for forming an image based on the image data of the calibration sheet a plurality of times (that is, continuously over a plurality of pages) is transmitted and output via the interface unit 15.

  Here, the number of times of image formation (number of pages to be formed) is a value stored in advance in the storage unit 12 as necessary page number information. This necessary page number information is updated by a process described later.

  Here, the image data serving as the basis of the calibration sheet includes an instruction to form a plurality of figures (color patches) filled with a single color, which are read during the calibration process. As an example, the primary color (single color of each color material) of C (cyan), M (magenta), Y (yellow), and K (black) color materials used by the printer 2 for image formation is changed from 0% to 100%, respectively. %, An instruction for forming a plurality of color patches each filled with a color corresponding to a value incremented by a predetermined ratio (for example, 5%) is included. Thus, for example, for each color of C, M, Y, and K, each color patch colored while changing by 5%, 0%, 5%, 10%... 95%, 100%, is formed (FIG. 2). A).

  One characteristic of the present embodiment is that an instruction to form a calibration patch group (corresponding to A in FIG. 2) actually used for calibration is included in the image serving as the basis of the calibration sheet. Separately, it includes an instruction to form a variation confirmation patch group used for measurement of inter-page density variation.

  Although an example in which the patch group actually used in the calibration sheet and the variation confirmation patch group are separately formed will be described here, a part of the patch group used in the calibration sheet is used as the variation confirmation patch group. It may be used as

  The change confirmation patch group formation instruction is also a filled figure (for example, a rectangle) formed with primary colors (single colors of the respective color materials) of the C, M, Y, and K color materials used by the printer 2 for image formation. Yes, each color material includes instructions for forming a plurality of color patches formed with at least three different densities. As a result, for example, as shown in FIG. 2B, three color patches (total of 12 color patches) formed at different densities for each of the four types of color materials C, M, Y, and K are formed. . Here, for each color of C, M, Y, and K, a color patch having a relatively low density, a color patch having a relatively high density, and a color patch having a density between them are formed. .

  In the printer 2, a plurality of calibration sheets illustrated in FIG. 2 are continuously formed and output. At this time, due to the characteristics of the printer 2, even if the page is output continuously, the color of the color patch formed corresponding to the formation instruction at the same density is not necessarily reproduced as the same color and may fluctuate.

  The user reads the color patches of the variation confirmation patch group formed on each calibration sheet in a predetermined order (hereinafter, for example, the formation order) for the plurality of calibration sheets. Then, the control unit 11 stores information on the reading result (color value (for example, value in RGB color space)) of the color patch of the variation confirmation patch group formed on each calibration sheet. Are stored in sequence.

  For example, the control unit 11 stores the read value in the storage unit 12 in association with information for specifying the calibration sheet (for example, a serial number given in the order of formation) and information for specifying the color patch. (Figure 3). For example, when the reading unit 16 is a colorimeter, the information specifying the color patch may be a serial number indicating the order of color measurement. In this case, the user reads each color patch included in the variation confirmation patch group in a certain order. When scanning with a flatbed scanner, etc., serial number in the scan line order (the order of scanning one line from left to right and moving to the next lower line when reaching the right end). And the serial number may be recorded as information for specifying the color patch.

  Hereinafter, for the sake of explanation, the reading result of the j-th color patch read in the variation confirmation patch group formed on the i-th calibration sheet stored in the storage unit 12, It is described as C (i, j).

  As shown in FIG. 4, the control unit 11 rearranges the reading results of the color patches in the order of formation (ascending order of the serial number i indicating the formation order) (S1). The result of this rearrangement represents the temporal variation (time-series variation) of the density of the color patch formed on each calibration sheet by the printer 2. Then, the control unit 11 estimates the number of pages to be formed until a calibration sheet that satisfies a predetermined condition is formed based on the information indicating the time series change.

  That is, the control unit 11 starts a condition determination loop for each color patch included in the variation check patch group in order from i = 2 (second formed calibration sheet), and the i th calibration sheet , The color difference Δ (j) = C (i, j) −C (i−1, j) between the i−1th calibration sheet and the jth color patch formed on each is calculated (S2). ). Then, it is determined whether Δ (j) is less than a predetermined threshold value (S3). If it is not less than the threshold value, the condition determination loop is exited and i is incremented by “1” (S4). ) If i is equal to or less than the number N of sheets to be formed, the processing in the condition determination loop is performed again. Here, the threshold value may be set in advance as a different value for each color patch (for each j). The color difference may be a difference in brightness, or may be a Euclidean distance between coordinates represented by each color component (R, G, B components, etc.).

  At this time, if i exceeds the number N of sheets to be formed, the density variation of the color patch formed on the calibration sheet has not been stabilized until the current number N of sheets to be formed. Processing such as displaying an error for the unit 14 (error handling processing) is performed (S5), and the processing is terminated.

  If it is less than the threshold value in step S3, j is incremented by “1” (S6), and if j is less than or equal to the number of color patches included in the variation confirmation patch group, When the process is repeated and j exceeds the number of color patches included in the change confirmation patch group, the condition determination loop is exited, and the value of i at that time is used as the density change of the color patch formed on the calibration sheet. Represents the number of formations required until the image becomes stable, and is stored in the storage unit 12 as the required number of pages (S7).

  Thereafter, when receiving a calibration start instruction, the control unit 11 causes the printer 2 to form calibration sheets as many as the number of required pages. The user performs calibration using the calibration sheet formed last.

  In addition, the above-described process of updating the necessary number of pages may be performed at each calibration timing.

  Depending on the state of the printer 2, the number of sheets formed until the density fluctuation is stabilized (Δ (j) in the process S3 is less than the threshold value) may be considered. A display prompting re-output of the calibration sheet may be performed. At this time, the number of calibration sheets to be additionally output may be arbitrarily set. In this case, when the calibration sheet is output again and the density fluctuation is stable, the accumulated number of the previously output number and the re-output number is stored in the storage unit 12 as the required number of pages. .

  If the density fluctuation is not stable, calibration may be forcibly performed using the final output sheet. Also in this case, the cumulative number of the previously output number and the re-outputted number may be stored as the required number of pages.

  The update of the required number of pages may be determined in consideration of the past required number of sheets, not every time calibration is performed. In this case, the control unit 11 records a history of the required number of pages in the past multiple times, and a threshold value in which a difference between the average value of the required pages up to the previous time and the previous required number of pages is predetermined. The required number of pages may be updated when the number exceeds.

  For example, when the required number of pages in the past six times has changed to 10, 11, 10, 13, 11, 4, the average value until the previous time is “11”, and the difference from the previous time is “7”. Yes. At this time, when the threshold value is set to “5”, the required number of pages is updated.

  Here, a condition that the density difference with the color patch formed immediately before is less than a predetermined threshold is used as a determination condition that the density variation of the color patch formed on the calibration sheet is stable. Although an example has been described, in addition to this, a method that uses a method for determining convergence, such as a method using a moving average change amount, is used, and a value that indicates the order in which the calibration sheets are formed when it is determined to have converged is required. It may be the number of pages.

  Thus, according to the present embodiment, considering the density fluctuation between pages in the calibration sheet, the number of continuously formed sheets until the time change of the density fluctuation becomes stable is examined, Since the calibration is executed using the calibration sheet (when the required number of pages are formed), the accuracy can be maintained and improved.

It is a block diagram showing the example of a structure of the calibration assistance apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the calibration sheet | seat which the calibration assistance apparatus which concerns on embodiment of this invention uses. It is explanatory drawing showing the example of storage of the read value in the calibration assistance apparatus which concerns on embodiment of this invention. It is a flowchart figure showing an example of processing which a calibration support device concerning an embodiment of the invention performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Calibration support apparatus, 2 Printer, 11 Control part, 12 Storage part, 13 Operation part, 14 Display part, 15 Interface part, 16 Reading part

Claims (5)

The image forming apparatus to be calibrated includes a plurality of color patches, and forming means for a plurality of pages formed by continuing the calibration sheet,
A reading unit that reads at least a part of the color patches formed on the calibration sheet of a plurality of pages formed by the forming unit as a variation checking patch group, and reads the color density of the color patch included in the variation checking patch group; ,
Number of pages required until a calibration sheet satisfying a predetermined condition is formed based on information representing a time-series change in the density of the color patch formed on each calibration sheet read by the reading unit Estimating means for estimating
Storage means for storing the required number of pages estimated by the estimation means;
Including
A calibration support apparatus, wherein the information on the required number of pages stored in the storage means is used for a calibration sheet forming process. The calibration support apparatus according to claim 1,
The calibration support apparatus, wherein the variation confirmation patch group is formed separately from a calibration patch group used for calibration. The calibration support apparatus according to claim 1, wherein:
The calibration support apparatus, wherein the variation confirmation patch group is formed separately for each color material used by the image forming apparatus to be calibrated for image formation. For the image forming apparatus to be calibrated, a plurality of calibration sheets including a plurality of color patches are continuously formed, and a plurality of pages are formed.
As variation check patch group at least some of the color patches formed on the calibration sheet of a plurality of pages which are the form, reads the density of a color of the color patches included in the change confirmation patch group,
Based on the read information representing the time-series change in the density of the color patch formed on each calibration sheet, the number of pages required until a calibration sheet that satisfies a predetermined condition is formed is estimated. ,
Storing the estimated required number of pages ;
A calibration support method, wherein the stored information on the required number of pages is used for a calibration sheet forming process. The computer,
The image forming apparatus to be calibrated includes a plurality of color patches, and forming means for a plurality of pages formed by continuing the calibration sheet,
A reading unit that reads at least a part of the color patches formed on the plurality of calibration sheets formed by the forming unit as a variation confirmation patch group, and reads the color density of the color patch included in the variation confirmation patch group;
Number of pages required until a calibration sheet satisfying a predetermined condition is formed based on information representing a time-series change in the density of the color patch formed on each calibration sheet read by the reading unit Estimating means for estimating
Storage means for storing the required number of pages estimated by the estimation means ;
And the stored information on the necessary number of pages is provided to a calibration sheet forming process.

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