JP2008207381A - Printer and scanning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To configure a printer which realizes the setting of correction data by unerringly detecting a primary color exposure area formed by three primary color exposure in a test chart. <P>SOLUTION: In discriminating three kinds of primary color exposure areas corresponding to three primary colors as line indexes 43 in the position adjacent to a chart area CA of a test chart, a hue decision means decides on a highest density color from among three kinds of density values of C (cyan), M (magenta), and Y (yellow) from the data of an area 43E from among the data of the test chart, where the line index should be present as a hue of the primary color exposure area. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes an exposure head in which a plurality of light quantity control units that perform light emission control of the three primary colors are arranged along the main scanning direction, and the exposure head and the recording medium are relative to each other in the sub-scanning direction orthogonal to the main scanning direction. A test chart creation unit that exposes a test chart to the recording medium by light emission control in the light amount control unit while being moved, and by scanning a test chart generated by exposure in the test chart creation unit with a scanner The present invention relates to a printing apparatus including a correction data setting unit that obtains densities of pixel line regions corresponding to the plurality of light quantity control units and sets correction data for the plurality of light quantity control units based on the densities.

  As a photographic printing apparatus configured as described above, exposure in the main scanning direction is performed by sending light rays of the three primary colors R (red), G (green), and B (blue) downward to the exposure head. A fluorescent light emitting tube (light quantity control unit of the present invention) is provided, and the chart light is exposed to the photographic paper while controlling the light quantity of the three primary colors with this fluorescent light emitting tube, and from the test chart created by this exposure Obtained as data separated into three primary colors of C (cyan), M (magenta), and Y (yellow) by a flatbed scanner, and obtained the density of each pixel line area from this data. There exist some which set a processing form so that correction data may be set based on it (for example, refer patent document 1).

JP-A-2006-301001 (paragraph numbers [0019] to [0062], FIGS. 1 to 10)

  In Patent Document 1, when a plurality of light emitting elements arranged along the main scanning direction are given consecutive numbers and a test chart is created, one of the end positions that sandwich the region of the chart body in the sub scanning direction. The end of the pixel line corresponding to the light emitting element to which the odd number is given is formed so as to protrude, and the light emission having the even number is given to the other of the end positions sandwiching the area of the chart body in the sub-scanning direction The end of the pixel line corresponding to the element is formed so as to protrude, and the density of the pixel line in the sub-scanning direction can be acquired with the end of the protruding pixel line as the reference.

  In this type of printing apparatus, exposure of the three primary colors is controlled corresponding to one pixel of the exposure head, and the exposure position by the light emitting elements of the three primary colors corresponding to one pixel is along the main scanning direction. There are slight differences. Although this difference is an extremely small value, when setting correction data based on the density of the exposure line, it is necessary to specify a pixel line corresponding to each of the three primary colors.

  Therefore, assuming that an exposure area corresponding to the three primary colors is formed by independently performing exposure corresponding to the three primary colors on the protruding portion of the pixel line, main scanning of each area corresponding to the three primary colors is assumed. In order to accurately specify the position in the direction, it is necessary to determine areas corresponding to the three primary colors (C (cyan), M (magenta), and Y (yellow) areas) from the data acquired by the flatbed scanner. . In order to make this determination, for example, a threshold value corresponding to the density of the color of the exposure region corresponding to the three primary colors is set in the test chart, and a density exceeding the threshold value is specified as a pixel line of the hue. Conceivable.

  However, setting a threshold value suppresses false detection caused by dust or the like adhering to the test chart. However, depending on the coloring characteristics of the photographic paper used for the test chart, it is caused by insufficient density. Thus, it was considered that it was difficult to specify a region corresponding to the three primary colors of the projecting portion. In particular, in printing devices that use many types of photographic paper, the color of the photographic paper to be used is often not fixed. In some aspects, it is difficult to set an appropriate threshold value for specifying a pixel line. Incidentally, when using a plurality of types of photographic paper, it may be possible to set a threshold value for each type of photographic paper, but setting a plurality of threshold values takes time and labor, and is not effective.

  An object of the present invention is to rationally configure a printing apparatus that reliably detects a primary color exposure area formed by exposure of three primary colors in a test chart and realizes setting of correction data.

A feature of the present invention is that it includes an exposure head in which a plurality of light quantity control units that perform light emission control of three primary colors are arranged along the main scanning direction, and the exposure head and the recording medium are arranged in a sub-scanning direction orthogonal to the main scanning direction. A test chart creation unit that exposes the chart to the recording medium by light emission control in the light amount control unit while being relatively moved, and scanning the test chart generated by the exposure in the test chart creation unit with a scanner A printing apparatus including a correction data setting unit that obtains the density of a pixel line region corresponding to the plurality of light quantity control units and sets correction data for the plurality of light quantity control units from the density,
The test chart creating unit continuously performs at least one exposure of the three primary colors under the control of the light amount control unit, thereby forming the pixel line region, and the control of the light amount control unit. Line index forming means for forming three primary color exposure areas corresponding to the three primary colors as line indices at the end of the pixel line area in the sub-scanning direction by exposing the three primary colors at different timings;
The correction data setting unit specifies line index specifying means for specifying the position of the line index from the information of the test chart acquired by the scanner, and the pixel line based on the position of the line index specified by the line index specifying means. A density acquisition unit that acquires the density of the region; and a correction data setting unit that sets the correction data based on the density acquired by the density acquisition unit;
When the line index specifying unit specifies the line index from the test chart, it compares the densities of the three primary color exposure areas, and determines the color with the highest density as the hue of the primary color exposure area. The hue determination means is provided.

  According to this configuration, when the test chart is created, the pixel line area creating unit of the test chart creating unit performs pixel line exposure, and the line index forming unit sets the three primary color exposure areas corresponding to the three primary colors. Form as an indicator. Thereafter, when the pixel line area is specified by scanning the test chart with a scanner, the line index specifying means determines the color having the highest density among the three primary color exposure areas as the hue of the primary color exposure area. Thus, the density acquisition unit acquires the density of the pixel line corresponding to the hue, and the correction data setting unit can set the correction data for each of the three primary colors based on the density. In other words, even when the density of the primary color exposure areas constituting the line index is generally low for the three primary colors, the highest density of the primary color exposure areas is set as the hue of the primary color exposure area so that it cannot be detected. The inconvenience that falls is eliminated. As a result, a printing apparatus that can detect the primary color exposure areas formed by the exposure of the three primary colors in the test chart and can set the correction data is rationally configured.

  In the present invention, the line index specifying unit specifies the position of the primary color exposure area in the main scanning direction for each hue, and the area in the sub-scanning direction based on the primary color exposure area thus specified May be set as the pixel line area, and in such a configuration, an area in the sub-scanning direction with reference to the position of the primary color exposure area in the main scanning direction is set as the pixel line, and the density is set. By acquiring, correction data corresponding to light emission control of the three primary colors can be set.

  According to the present invention, the line index specifying unit specifies a central position in the main scanning direction of the primary color exposure region of each hue, and the density acquisition unit is configured to determine a region corresponding to the central position in the pixel line region. In this configuration, the central position of the primary color exposure area of each hue in the main scanning direction is set, and the density of the area corresponding to the central position is acquired from the pixel line area. Therefore, the correction data can be set with high accuracy by eliminating the influence of the pixel line adjacent to the pixel line area (the influence of the light beam at the time of exposure of the adjacent pixel line).

  According to the present invention, the line index specifying unit allows a process of comparing the density of the primary color exposure area with a preset threshold value and determining a value exceeding the threshold value as a hue of the primary color exposure area. With this configuration, the hue of the primary color exposure area can be determined in a state where the density of all three primary colors is excluded with the density being too low by comparing the highest density with the threshold value. In addition, erroneous processing due to the influence of dust or the like attached to the test chart can be eliminated.

According to the present invention, the exposure head and the recording medium are moved relative to each other in the sub-scanning direction orthogonal to the main scanning direction, and the test chart prepared by exposing the chart with the exposure head is scanned with the scanner, thereby In the scanning method of setting correction data for the light amount control unit arranged along the main scanning direction,
When the chart is exposed, a pixel line area is formed on the test chart by the light amount control by the light amount control unit, and the exposure of the three primary colors is performed at different timings by the light amount control unit. The primary color exposure area of the seed is formed as a line index,
At the time of scanning, the position of the pixel line area in the main scanning direction is specified based on the line index, the correction data is set based on the density of the specified pixel line area, and the three primary color exposure areas May be determined as the hue of the primary color exposure region.

  According to this configuration, when the chart is exposed, the pixel line area is formed by the light amount control by the light amount control unit, and the three primary colors corresponding to the three primary colors are exposed by performing the exposure of the three primary colors at different timings by the light amount control unit. A region is formed as a line index. In the subsequent scanning, the position of the pixel line area in the main scanning direction is specified based on the line index, correction data is set based on the density of the pixel line area, and the densities of the three primary color exposure areas are set. A comparison is made and the one with the highest density is determined as the hue of the primary color exposure region. In other words, even when the densities of the primary color exposure areas constituting the line index are generally low for the three primary colors, the highest density among the primary color exposure areas is set as the hue of the primary color exposure area. Can be eliminated. As a result, a method for realizing the setting of the correction data by reliably detecting the primary color exposure areas formed by the exposure of the three primary colors in the test chart has been constructed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Configuration of printing device]
As shown in FIG. 1, a printing apparatus is configured to include an operating unit A and a print processing unit B. The operating section A includes a film scanner 2 that captures the image information of the photographic film F as a digital signal on the upper surface of the table 1, a display 3 that displays processing information, and a keyboard 4, and a flat bed scanner 5 on the side. I have. A processing device 6 composed of a general-purpose computer is provided below the table 1, and this processing device 6 stores image data recorded on a CD-R, DVD-R, or the like, or image data recorded on a semiconductor medium. A media drive 7 is provided.

  The flat bed scanner 5 is formed with a scanning table 5B made of a transparent glass plate or resin plate on the upper surface of the main body 5A, and an openable / closable platen cover 5C that covers the scanning table 5B, and a parallel movement within the main body 5A. And a free scanner unit 5D.

  The scanner unit 5D emits a light source (not shown) in a state where a scanning object is set on the scanning table 5B, and operates the scanner unit 5D in the sub-scanning direction orthogonal to the main scanning direction. A photoelectric conversion element (not shown) acquires an image of the scanning target set in the table 5B at every predetermined timing synchronized with the operation in the sub-scanning direction. As a result, C (cyan), M ( Bit map data having a gradation of at least 8 bits for each of the three primary colors of magenta and Y (yellow) is acquired. The flatbed scanner 5 has a pixel line area Q formed in a line in the sub-scanning direction when scanning is performed using a photographic paper P (an example of a recording medium) as a scanning object by light emission of a light emitting element 18 described later. (See FIG. 6) is divided into five or more areas in the main scanning direction and has a resolution capable of acquiring the density of each area.

[Print processing section]
The print processing section B cuts the photographic paper P as a recording medium into a print size in the exposure section EX, and then exposes the image data. After this exposure, the photographic paper P is reversed in the vertical conveyance device CV. Then, the paper is transported upward with the front and back sides thereof exchanged and sent to the development processing unit DE, and the photographic paper P developed by the development processing unit DE is dried by the drying processing unit DR and then laterally placed on the transport belt 10. Further, it is sent out from the conveyor belt 10 to a sorter (not shown).

  The exposure unit EX feeds the photographic paper P from the photographic paper magazine M with the pressure supply roller 11, cuts it into a print size with the cutter 12, feeds it horizontally with the chucker 13, and feeds it from the chucker 13 to the exposure position. At this exposure position, the image data is exposed by light rays from the exposure head H while conveying the photographic paper P in the horizontal sub-scanning direction. In addition, a control unit 14 is provided inside the exposure unit EX.

  The exposure head H includes a fluorescent light emitting tube 15 that sends light beams of three primary colors of R (red), G (green), and B (blue) downward, and conveys the photographic paper P based on the exposure position. A pair of exposure transport rollers 16 disposed on the upper side and the lower transport side, and a driven roller 17 corresponding to the exposure transport roller 16 are provided. The fluorescent tube 15 is a general term for a fluorescent tube 15R that emits light in R (red), a fluorescent tube 15G that emits light in G (green), and a fluorescent tube 15B that emits light in B (blue).

  In this exposure head H, the three types of fluorescent tubes 15R, 15G, and 15B corresponding to the three primary colors of R (red), G (green), and B (blue) are in a vacuum state that allows light to pass through, such as transparent glass. 2 has a structure in which a plurality of light emitting elements 18 (an example of a light amount control unit) are arranged in a linear array type in the main scanning direction as shown in FIG. In this exposure head H, light of the three primary colors is obtained by transmitting the light from the light emitting element 18 through filters (not shown) corresponding to R (red), G (green), and B (blue). These light emitting elements 18 control the luminance of the light emitting elements 18 by adjusting the voltage applied to the electrodes corresponding to the respective light emitting elements 18.

  As shown in FIG. 2, the plurality of light emitting elements 18 are arranged in the fluorescent light emitting tube 15 in a positional relationship in which a light emitting element 18 </ b> A assigned with an odd number as an element number and a light emitting element 18 </ b> B given an even number are parallel to each other. It is arranged in a row inside.

  Further, the light emission timing of the light emitting element 18A to which the odd number is assigned as the element number and the light emitting element 18B to which the even number is assigned as the element number is controlled to form a line shape in the main scanning direction with respect to the photographic paper P. When exposure is performed, as shown as an exposure dot pattern in FIG. 3, an exposure region in which numbers surrounded by exposure dots () formed by light emission of the light emitting elements 18 </ b> A to which odd numbers are given are odd numbers ( Pixel))) and the exposure dot (exposure region (pixel) in which the number surrounded by () is an even number) formed by light emission of the light emitting element 18B to which the even number is assigned slightly overlap in the main scanning direction.

  In the present invention, as the exposure head H, for example, only red may be replaced with a light emitting diode, or all may be replaced with a light emitting diode (an example of a light amount control unit). Furthermore, in the present invention, the exposure head H is provided with a plurality of liquid crystal type shutters (an example of a light amount control unit) along the main scanning direction in the path for guiding the light beam from the light source to the photographic paper P, and the shutters are used to form pixels. What controls the light quantity for every may be used.

  The vertical conveyance device CV includes a conveyance system that receives the photographic paper P exposed by the exposure head H with a pressure-bonding roller, moves it upward in a reversed form, and sends it to the development processing unit DE. In the processing unit DE, development processing is performed by sequentially feeding the fed photographic paper P to a plurality of development processing tanks by a roller having a pressure roller. Further, in the drying processing section DR, the photographic paper P is dried by heat from the infrared heater and drying air from a blower (not shown).

[Printer control system]
A control system of the printing apparatus is shown in FIG. That is, the processing device 6 includes a microprocessor (CPU) and an input / output interface 20 for inputting / outputting information to / from the microprocessor (CPU). The film scanner 2 is connected to the input / output interface 20. , An input / output system for accessing information among the display 3, the keyboard 4, the flatbed scanner 5, the media drive 7 and the hard disk HD. Further, an input / output system for accessing information is formed among the operating system 21, the normal print unit 22, the test chart creating unit 23, the scanner control unit 24, and the correction data setting unit 25 with respect to the data bus of the microprocessor CPU. is doing.

  The operating system 21 displays information necessary for the processing device 6 on the display 3, and in the state where the information is displayed on the display 3, for example, when normal print processing is performed according to the order information, the image to be printed is displayed. It functions as an interface that realizes processing for acquiring data and order data and transferring them to the normal print unit 22.

  The normal print unit 22 transmits the image data acquired from the film scanner 2 or the media drive 7 and the order information acquired via the keyboard 4 or the like to the print processing unit B to realize the printing process.

  The test chart creating unit 23 transmits exposure data corresponding to the chart and control data for executing print processing to the print processing unit B, so that the print processing unit B exposes the chart on the photographic paper P. And a test chart TC shown in FIG. 5 is obtained.

  The test chart creation unit 23 continuously performs at least one exposure of three primary colors to form the pixel line region Q, and performs the exposure of three primary colors at different timings. Line index forming means for forming three primary color exposure areas corresponding to the three primary colors as line indices (a superordinate concept of the front line index 43 and the rear line index 44) at the end of the pixel line area Q in the sub-scanning direction. 23B.

  The scanner control unit 24 realizes a process of acquiring scanning data from a set scanning object (test chart, photographic paper P, etc.) and loading it into the processing device 6 by controlling the flatbed scanner 5.

  The correction data setting unit 25 generates correction data from the scanning data acquired by scanning the test chart TC with the flatbed scanner 5, transmits the correction data to the print processing unit B, and updates the correction table 35. (Set).

  The correction data setting unit 25 includes a line index specifying unit 25A, a density acquisition unit 25B, a correction data setting unit 25C, and a hue determination unit 25X.

  The line index specifying unit 25A specifies the position of the line index from the data of the test chart TC acquired by the flatbed scanner 5. The density acquisition unit 25B acquires the density of the pixel line region based on the position of the line index specified by the line index specification unit 25A. The correction data setting unit 25C sets the correction data based on the density acquired by the density acquisition unit 25B. The hue determining unit 25X compares the color densities of the three primary color exposure areas when the line index specifying unit 25A specifies the line index from the test chart TC, and the color having the highest density is exposed to the primary color. Processing to determine the hue of the region is performed.

  The control unit 14 includes a microprocessor (CPU) and an input / output interface 30 for inputting / outputting information to / from the microprocessor (CPU). With respect to the input / output interface 30, the temperature of the developing processing liquid in the plurality of developing processing tanks of the transport unit, the exposure head H, and the developing processing unit DE that transports the photographic paper P in each part of the print processing unit B A development processing unit that performs liquid level management and an input / output system for each of the magazine sensors MS that specify the type of the photographic paper magazine M are provided. Also, an input / output system for accessing information is formed among the operating system 31, the conveyance control unit 32, the exposure control unit 33, the development control unit 34, and the correction table 35 with respect to the data bus of the microprocessor (CPU). ing.

    The operating system 31 performs a process of acquiring a signal from a sensor system (not shown) and a basic process of outputting a control signal to various control systems, as well as the transport control unit 32, the exposure control unit 33, The processing of each development control unit 34 is realized. The conveyance control unit 32 controls the conveyance unit to realize conveyance of the photographic paper P. The exposure control unit 33 controls the exposure head H to realize processing for exposing image data onto the photographic paper P. The development control unit 34 realizes processing for managing the liquid temperature and the liquid level of the processing liquid in the development processing unit DE. The magazine sensor MS outputs information specifying the type of photographic paper P by specifying the photographic paper magazine M.

  The correction table 35 has three primary colors of R (red), G (green), and B (blue) so as to set the luminance of the light emitting elements 18 of the respective fluorescent light emitting tubes 15R, 15G, and 15B in the exposure head H. The correction data group includes three types of correction data groups, and correction data composed of coefficients associated with the element numbers for identifying the light emitting elements are stored in the correction data groups.

  The normal printing unit 22, the test chart creating unit 23, the scanner control unit 24, the correction data setting unit 25, and the conveyance control unit 32, the exposure control unit 33, and the development control unit 34 in the control unit 14 are respectively included in the processing device 6. Although it is assumed that the software is developed on a semiconductor memory (not shown), it can be configured by hardware such as logic, or may be configured by combination with hardware. The control system requires a control bus, an address bus, etc. in addition to the data bus in order to realize control. In order to avoid complication, the control bus, address bus, and interfaces are shown in the drawing. Not.

  In this printing apparatus, a test chart TC shown in FIG. 5 is created by exposing the preset chart to the photographic paper P by the test chart creating unit 23, and the test chart TC is created by the flatbed scanner. In step S5, the correction data setting unit 25 sets correction data and updates the correction data in the correction table 35.

[Test chart structure]
As shown in FIG. 5, the test chart TC has a chart area CA formed in an area sandwiched between a start bar 40 functioning as an index indicating the front side of the chart and an end bar 41 indicating the rear side of the chart. Yes. A front line index 43 corresponding to the light emitting element 18A to which the odd number is assigned is formed on the front side of the chart area CA, and light emission to which the even number is assigned is provided on the rear side of the chart area CA. A rear line index 44 corresponding to the element 18B is formed. Further, a center index 42 is formed at the center position in the main scanning direction between the front side and the rear side of the chart area CA.

  FIG. 6 shows an enlarged view of the front line index 43 and the rear line index 44. As shown in FIG. 6, the front line index 43 and the rear line index 44 are located at a position sandwiching the chart area CA. It is formed in a comb-teeth shape in a parallel posture. Note that the width of the front line index 43 in the main scanning direction coincides with the width in the main scanning direction of the exposure region by the light emitting element 18A to which the odd number is assigned, and the main scanning of the rear line index 44 is similarly performed. The width in the direction matches the width in the main scanning direction of the exposure region by the light emitting element 18B to which the even number is assigned. From such a structure, it is possible to identify the front line index 43 or the rear line index 44 corresponding to the element number on the basis of the center index 42 and obtain the density of the pixel line region Q corresponding to the element number. .

  The chart area CA has yellow (Y), magenta by exposure that causes the three light emitting elements 15B, 15G, and 15R of B (blue), G (green), and R (red) to independently emit light. (M) and three primary color regions 45 developed for cyan (C), an illegal color development region 46 for confirming the color development of the photographic paper P by exposure by light emission of a specific color during this exposure, and B (blue) , G (green), and R (red), the three types of fluorescent light-emitting tubes 15B, 15G, and 15R were exposed to light at the same time by changing the amount of emitted light to develop a different gray color 7 It is composed of a gray coloring region 47 of seeds.

  In the chart area CA, the light emitting elements 18 are exposed at the same position of the photographic paper P by light emission of the light emitting elements 18 (with odd numbers and even numbers) arranged in the main scanning direction of the exposure head H. Is formed along the sub-scanning direction with a width equal to the exposure width of the light emitting element 18 in the main scanning direction.

  In particular, since the three types of fluorescent light emitting tubes 15R, 15G, and 15B are each provided with the light emitting element 18, there are three light emitting elements 18 having the same element number. Therefore, even if there are three light emitting elements 18 having the same element number, there are cases where the exposure positions are slightly different in the main scanning direction, and thus the light emitting elements 18 having different exposure positions perform exposure. In this case, for example, the positions of the C (cyan) pixel line area Q and the M (magenta) pixel line area Q are slightly different in the main scanning direction.

[Correction table setting]
FIG. 11 is a flowchart illustrating an operation sequence (an example of a scanning method) when setting (updating) the correction table 35 in the printing apparatus. In this order of work, as described above, the test chart creation unit 23 creates the test chart TC by transmitting the image data corresponding to the chart and the control data for executing the printing process to the printing apparatus. Specifically, the image data corresponding to the chart is exposed on the photographic paper P, developed after this exposure by the development processing unit DE, and then dried by the drying processing unit DR and sent out. A TC is created (step #a).

  In this process, a pixel line area Q corresponding to each light emitting element 18 is formed by the process of the pixel line area forming unit 23A constituting the test chart creating section 23, and a line index constituting the test chart creating section 23 is formed. A line index is formed at the end of the pixel line region Q by the processing by the forming unit 23B. Even when exposure data corresponding to the chart is exposed as described above, the image data is corrected by the correction table 35 when the image data is transmitted to the exposure head H or before the transmission. The corrected test chart TC reflects the correction by the correction table 35.

  Next, scanning data is acquired by artificially setting the test chart TC on the flatbed scanner 5 and performing scanning (step #b). In this process, the scanner control unit 24 controls the flatbed scanner 5 so that the three primary colors of C (cyan), M (magenta), and Y (yellow) have a bitmap format having a gradation of at least 8 bits. Get scanning data.

  In this process, it is assumed that the exposure paper H is exposed to a length longer than the dimension of the exposure head H in the main scanning direction. However, the length of the printing paper slightly shorter than the dimension of the exposure head H in the main scanning direction is assumed. Two Ps are used and distributed in the main scanning direction. The image data of the same chart is exposed twice to create two test charts, and the two test charts are scanned for 2 A process of generating one piece of chart data may be performed by acquiring the chart data of one sheet and synthesizing these chart data.

  Next, processing for setting correction data from the scanning data is performed (step #c). This process is realized by the correction data setting unit 25. In this process, in particular, the line index specifying unit 25A specifies the front line index 43 and the rear line index 44, and the density acquisition unit 25B is used for the pixel line. The density of the region Q is acquired, and the correction data setting means 25C performs processing for setting correction data for each element number based on this density.

  The correction data set in this way is transmitted to the correction table 35 of the control unit 14 and automatically updated (#d step).

[Correction data generation routine]
It is possible to show the above-described process of step #c as a correction data generation routine, particularly as shown in the flowchart of FIG.

  In this routine, when the chart can be recognized from the scanning data, the coordinates of the data are converted based on the attitude of the chart (steps # 01 and # 02).

  Since the scanning data in the bitmap format has a structure in which pixels are aligned in the vertical direction and the horizontal direction, processing is performed by regarding the position of each pixel as an XY coordinate. If one of the directions does not coincide with the main scanning direction of the chart, coordinate conversion is performed so as to make them coincide with each other, thereby simplifying the subsequent processing. In this process, the posture of the line in the main scanning direction of the start bar 40 or the end bar 41 is discriminated, and scanning data is rotated so that the direction of this line is parallel to one of the XY directions. Coordinate conversion is performed by the above calculation.

  Next, a process of determining the position of the line index (front line index 43 and rear line index 44) is performed (step # 03). When the front line index 43 and the rear line index 44 are formed by exposure, the light emitting element 18 corresponding to R (red) alone is exposed and the light emitting element 18 corresponding to G (green) is exposed. By switching between the single exposure and the single exposure of the light emitting element 18 corresponding to B (blue), the front line index 43 has a C (cyan) primary color exposure region 43C as shown in FIG. Then, an M (magenta) primary color exposure region 43M and a Y (yellow) primary color exposure region 43Y are formed in parallel in the sub-scanning direction. As shown in FIG. 8, the primary line exposure area 44C, the primary color exposure area 44M, and the primary color exposure area 44Y are formed in parallel in the rear line index 44 as well.

  The formation positions of the primary color exposure areas 43C, 43M, and 43Y and the primary color exposure areas 44C, 44M, and 44Y in the sub-scanning direction are easily determined from the positions of the start bar 40, the end bar 41, or the chart area CA. When the position of the line index is specified, the hue determination unit 25X acquires data of the areas 43E and 44E where the line index should exist from the scanning data, and in this area 43E and 44E, C ( Cyan), M (magenta), and Y (yellow) densities are compared to determine the area with the highest density. Further, the color of the area where the density of the determined area exceeds a preset threshold TH The primary color exposure areas 43C, 43M, and 43Y corresponding to this color or primary color exposure areas 44C, 44M, and 44Y , It acquires the information of the primary exposure area.

  The outline of this process will be described based on a histogram of density values (density values) in the primary color exposure areas 43C, 43M, and 43Y. As shown in FIG. 10, C (cyan), M (magenta), and Y (yellow). The primary color exposure area is specified based on the one having the highest density value for the three primary colors and the density value exceeding the threshold value TH. In (a) at the left end of the figure, the density value of C (cyan) is the highest compared to the others and exceeds the threshold value TH, so that the hue of this primary color exposure region 43C is determined to be C (cyan). Then, the position of the primary color exposure area 43C is determined, and information indicating the area is acquired. In the middle (b) of the figure, the density value of M (magenta) is the highest compared to the others, and exceeds the threshold value TH. In the right (c) of the figure, the density value of Y (yellow). Is higher than the others and exceeds the threshold value TH. Thus, the color having the highest density value is determined as the hue of the primary color exposure region.

  As a process for determining the hue of the primary color exposure area by the hue determination unit 25X in this way, for example, a belt shape in the main scanning direction corresponding to the primary color exposure areas 43C, 43M, and 43Y and the primary color exposure areas 44C, 44M, and 44Y. May be set (six areas are set), and the processing form may be set so as to determine the density value of the corresponding color in each area.

  Next, only when the primary color exposure area can be specified, the sampling line SL parallel to the main scanning direction is set based on the primary color exposure areas 43C, 43M, and 43Y and the primary color exposure areas 44C, 44M, and 44Y. An area on the sampling line SL in the chart area CA is set as the sampling area QS (steps # 04 and # 05).

  More specifically, for example, when the positional deviation in the main scanning direction is very small as in the primary color exposure areas 43C, 43M, and 43Y as shown in FIG. 7, or when there is no positional deviation, FIG. As shown in FIG. 1, a single sampling line SL is set, and one sampling area QS is set. The sampling area QS is formed at a position included in the seven types of gray coloring areas 47 on one sampling line SL.

  As described above, since the scanning data has data that can decompose the pixel line area Q into five areas in the main scanning direction, when the minimum area that can be decomposed in this way is a data pixel, The sampling area QS includes a data pixel existing on the sampling line SL in the pixel line area Q and a data pixel adjacent to the data pixel in the main scanning direction, and a plurality of data pixels existing in the sub-scanning direction. The size of each sampling area QS is set to include.

  However, as described above, even in the same element number, the position in the main scanning direction is slightly different for each light emitting element 18 corresponding to R (red), G (green), and B (blue) (there is a deviation in the main scanning direction). There is also something to do. When exaggerating such a case and showing in the drawing, as shown in FIG. 9, three sampling lines SL are set, and one kind of gray color development region 47 corresponding to these sampling lines SL is set. By setting the sampling area QS, three sampling areas QS corresponding to C (cyan), M (magenta), and Y (yellow) are set for one type of gray coloring area 47.

  Next, the density value of the sampling area QS is acquired, the acquired density value is compared with the average density value of the area where the sampling area QS is formed, a density difference is obtained, and a density that compensates for this density difference is obtained. A coefficient for obtaining is set in the correction data (step # 06). If the sampling area QS cannot be specified, or if the chart cannot be recognized in step # 01, an error is output to the display 3 (step # 07) and the correction data setting routine is terminated.

  Since the sampling area QS includes a plurality of data pixels, an average value of the density values of the plurality of data pixels is set as the density value of the sampling area QS.

  When acquiring the density value (density value), the information of the sampling area QS of the gray color development area 47 is color-separated to obtain the densities of the three primary colors C (cyan), M (magenta), and Y (yellow). Processing to acquire a value is performed. By performing the same process for other pixel line regions Q, the average value of the density values for the three primary colors in the plurality of sampling regions QS is obtained, and the average value of the density values thus obtained is calculated. The correction data described above is set by obtaining the density difference from each sampling region QS.

  Since the correction data set in this way is given by a coefficient associated with the element number, the correction table 35 is updated by performing a process of multiplying this coefficient by the correction data of the element number already existing in the correction table 35. It will be realized.

[Concept of the Invention]
Thus, according to the present invention, the line index formed at a position adjacent to the chart area CA of the test chart TC (the superordinate concept of the front line index 43 and the rear line index 44) corresponds to 3 primary colors. Although it is composed of various primary color exposure areas (43C, 43M, 43Y, and 44C, 44M, 44Y), C (cyan), M (magenta), Y ( The color corresponding to the color having the highest density value by comparing the three density values of yellow) and exceeding the set threshold value is used as the primary color exposure area of the color, and the hue of the primary color exposure area The position of the primary color exposure area can be easily determined even if the density value is low due to, for example, the color development characteristic being different from that assumed in advance. By eliminating the influence of wear, etc. are those that can eliminate the wrong treatment. After determining the position of the primary color exposure region in this way, the correction data can be set by acquiring the density value of the sampling region QS.

  In particular, even if the formation positions of the three primary color exposure areas (43C, 43M, 43Y, and 44C, 44M, 44Y) are set to positions slightly displaced in the main scanning direction, the corresponding light emission Since the position of the pixel line area Q exposed by the element 18 is set with high accuracy and the density value of the corresponding sampling area QS is acquired, the light emitting elements 18 of R (red), G (green), and B (blue) are obtained. Correction data can be set accurately.

The figure which shows the constitution of the photograph printing device typically The figure which shows arrangement | positioning of a light emitting element typically. Diagram showing exposure dot pattern Block diagram of control system Diagram showing test chart Enlarged view showing test chart structure Diagram showing the relationship between front line index and sampling area Diagram showing the relationship between rear line index and sampling area Enlarged view showing the primary color exposure area in the misalignment state The figure which shows the histogram and threshold value of the density value of a primary color exposure area | region Flow chart showing the sequence when setting the correction table Flow chart of correction data setting routine

Explanation of symbols

5 Scanner (Flatbed scanner)
18 Light intensity control unit (light emitting element)
23 Test chart creation unit 23A Pixel line area formation unit 23B Line index formation unit 25 Correction data setting unit 25A Line index identification unit 25B Density acquisition unit 25C Correction data setting unit 25X Hue determination unit 43 Line index (front line index)
44 Line indicator (rear line indicator)
H Exposure head P Recording medium (photographic paper)
Q Pixel line area TC Test chart

Claims (5)

An exposure head having a plurality of light quantity control units that perform light emission control of the three primary colors is arranged in the main scanning direction, and the exposure head and the recording medium are moved relative to each other in the sub-scanning direction orthogonal to the main scanning direction. A plurality of light quantity controls are provided by scanning a test chart generated by exposure in the test chart creating section with a test chart creating section that exposes a chart on the recording medium by light emission control in the light quantity control section. A printing apparatus including a correction data setting unit that obtains the density of a pixel line region corresponding to a portion and sets correction data for the plurality of light quantity control units based on the density,
The test chart creating unit continuously performs at least one exposure of the three primary colors under the control of the light amount control unit, thereby forming the pixel line region, and the control of the light amount control unit. Line index forming means for forming three primary color exposure areas corresponding to the three primary colors as line indices at the end of the pixel line area in the sub-scanning direction by exposing the three primary colors at different timings;
The correction data setting unit specifies line index specifying means for specifying the position of the line index from the information of the test chart acquired by the scanner, and the pixel line based on the position of the line index specified by the line index specifying means. A density acquisition unit that acquires the density of the region; and a correction data setting unit that sets the correction data based on the density acquired by the density acquisition unit;
When the line index specifying unit specifies the line index from the test chart, it compares the densities of the three primary color exposure areas, and determines the color with the highest density as the hue of the primary color exposure area. A printing apparatus provided with hue determination means.   The line index specifying means specifies the position of the primary color exposure area in the main scanning direction for each hue, and sets the area in the sub-scanning direction based on the primary color exposure area specified in this way as the pixel line. The printing apparatus according to claim 1, wherein the printing apparatus sets the area.   The line index specifying means specifies a central position in the main scanning direction of the primary color exposure area of each hue, and the density acquisition means acquires the density of an area corresponding to the central position in the pixel line area. The printing apparatus according to claim 2.   The line index specifying unit compares the density of the primary color exposure area with a preset threshold value, and permits a process of determining a hue exceeding the threshold value as a hue of the primary color exposure area. The printing apparatus according to any one of the above. By exposing the chart with the exposure head while relatively moving the exposure head and the recording medium in the sub-scanning direction orthogonal to the main scanning direction, and scanning the created test chart with the scanner, the exposure head is moved in the main scanning direction. A scanning method for setting correction data for a light amount control unit arranged along a line,
When the chart is exposed, a pixel line area is formed on the test chart by the light amount control by the light amount control unit, and the exposure of the three primary colors is performed at different timings by the light amount control unit. The primary color exposure area of the seed is formed as a line index,
At the time of scanning, the position of the pixel line area in the main scanning direction is specified based on the line index, the correction data is set based on the density of the specified pixel line area, and the three primary color exposure areas Is a scanning method in which the density of the primary color is compared and the highest density is determined as the hue of the primary color exposure area.

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