JP4413162B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer or a copying machine, and more particularly to an image forming apparatus having an image forming function for adjusting the amount of a color material, that is, a printing paint such as toner or ink.

  In recent years, with the development of the technical field of image forming apparatuses such as printers and copiers, particularly color image forming apparatuses, it has become possible to output high-quality printed matter at high speed, and the frequency of use of color image forming apparatuses has increased, and documents and drawings The amount of output in printed materials such as photographs and photographs has increased remarkably. Such an increase in the output amount of the printed matter promotes wasteful use of color materials such as printing paints, and therefore there has been a problem of an increase in running cost of the color materials that are consumables.

  In order to solve such a problem, various image forming apparatuses having a printing function in a so-called economy mode that perform printing while suppressing consumption of color materials have been proposed. For example, the following Patent Document 1 (Japanese Patent Laid-Open No. 10-278349) discloses an optimum print density for a print control apparatus (image forming apparatus) capable of switching the print density by controlling the amount of color material such as printing paint. Has been disclosed, and a printing control apparatus capable of reducing the amount of color material is disclosed.

  According to the printing control device disclosed in Patent Document 1, in the printing at the time of economy instruction, the printing mechanism unit is used in both the first and second printing process mechanism units than the printing at the time of normal instruction. Since the first and second printing process mechanism units are controlled so as to reduce the amount of color material attached to the print medium, the amount of color material can be greatly reduced without increasing the cost of the apparatus. Can be saved.

  Further, in the following Patent Document 2 (Japanese Patent Laid-Open No. 8-183203), an image forming method and apparatus for forming an image by reducing the number of recording members, the amount of color material only in the interior while leaving the outline of a predetermined object image is disclosed. There has been disclosed an image forming method and apparatus capable of forming an easy-to-view image by reducing the amount and efficiently reducing the amount of color material while maintaining the image quality of other regions.

  According to the image forming method disclosed in Japanese Patent Application Laid-Open No. H10-228707, the image of the portion where the color material amount is reduced is formed so as not to be noticeable, thereby minimizing the deterioration of the image appearance, Identification can be facilitated.

  Furthermore, according to the image forming apparatus described in the following Patent Document 3 (Japanese Patent Application No. 2005-018979) relating to the application of the present applicant, a function capable of adjusting the amount of the color material is provided in order to solve the above problems. An image forming apparatus that counts the number of colors of object image data, determines whether to reduce the amount of color material based on the counted number of colors data and a predetermined threshold, and the number of colors exceeds the threshold An image forming apparatus in which the amount of color material is reduced only when there is no image is shown.

  According to the image forming apparatus described in Patent Document 3, by using a simple determination method of counting the number of colors, it is possible to meet general user requirements for output image quality without increasing the processing time and cost of the image forming apparatus. can do.

JP 10-278349 A (Claim 1, paragraphs [0009] and [0010]) JP-A-8-183203 (claims 21, 34, 35, paragraphs [0004], [0009] to [0011], [0015] to [0017]) Japanese Patent Application No. 2005-018979

  However, according to the print control apparatus described in Patent Document 1, when the economy instruction is set, the color material amount is reduced for the entire page of the image to be printed, and the quality of the entire page is reduced. Inviting, the overall image quality deteriorates. For this reason, when there is an object (image data) that does not want to reduce image quality in the page, the image quality of the object naturally deteriorates.

  Further, in the image forming method described in Patent Document 2, it is necessary to take an image processing time for the process of extracting an object region whose color material amount should be reduced from the image data, which requires an output time and smooth output. Was not obtained.

  Furthermore, in the image forming apparatus disclosed in Patent Document 3, the entire object image data is an analysis target, and whether or not to reduce the color material amount is determined after analyzing the entire object image data. Therefore, the processing time is relatively long.

  On the other hand, the user desires high image quality for predetermined image data and desires to save the cost such as the amount of color material for other image data, but also desires image output in a short time at the same time. It is normal.

Accordingly, the inventors of the present application have made various investigations to solve the above-described problems, and as a result, the present invention aims to shorten the determination processing time for reducing the amount of color material and not deteriorate user-friendliness. Has been completed.

  An object of the present invention is to solve the above-described problems, and uses a simple determination method of an image dividing unit and a color number counting unit and an image processing method for performing the same processing on a plurality of objects in parallel. .

The invention according to claim 1 of the present application performs the color number counting process of the object image data (for example, in the color number counting unit) and reduces the color material amount based on the counted color number (for example, the color material amount reduction determination). The image forming apparatus includes an image processing unit that can perform adjustment of the color material amount (for example, in the color material amount reduction execution unit) based on the determination result. The image processing unit includes object image data Based on the detection result of the image size detection means, the division determination means for determining whether or not to divide the object image data into a predetermined number based on the detection result by the image size detection means, and the determination result by the division determination means Image data dividing means for dividing object image data into a predetermined number, and image data divided by the image data dividing means Parallel example Bei and a parallel processing means for performing the color number count processing for each, the image processing section, when the number of counted color after the count is determined to exceed the predetermined number of colors threshold Is characterized by not reducing the amount of color material .

  Here, as a method for extracting the number of colors, a known RGB method, luminance / color difference signal method, chromaticity coordinate method, and HSV method can be used. The RGB method is a method in which a range is provided for each signal of R (red), G (green), and B (blue), and colors that fall within the range are extracted. The luminance / color difference signal method is a method in which a RGB signal is converted into a luminance signal Y, a color difference signal RY, and a color difference signal BY to provide a range, and colors within the range are extracted. According to the chromaticity coordinate system, RGB signals are approximately converted into chromaticity coordinate x-value y values in the XYZ color system, a range is provided for each x-value y value, and colors within that range are extracted. It is a method. In the HSV system, RGB signals are converted into H (Hue), S (Saturation), and V (Value (Brightness)) to provide a range, and the colors within the range are set. This is a method of extracting.

  Further, as a method of counting the number of colors, for example, a method of counting the number of colors of received image data according to the extracted contour can be considered. Specifically, first, the value of the counter memory in the color number counting unit is initialized to zero. For example, in the case of 24-bit color, each RGB maximum luminance value L of the object image data is 255, and each luminance value l is represented by R (x, y), G (x, y), B (x, y). If so, each time the color is counted, these values are incremented by one. The main scanning direction size is m, the sub-scanning direction size is n, x is incremented by 1 when x <m, and y is incremented by 1 when y <n.

  Further, the “image size detecting means” detects the size of the effective image of the object, and the document size, the sub-scanning direction (corresponding to the paper feeding direction) size and the main scanning direction (paper width) of the effective image. This can be done by detecting a colored area of the same size as the direction. That is, the image size is obtained from the density difference by setting the output level to MAX for colored (for example, black) and MIN for the colorless.

  Furthermore, the “image data dividing means” is a means for speeding up the image processing, that is, the color count, and prints out each divided image or prints out the boundaries of the divided images. It is not something to do. Therefore, in order to perform image division processing, a coordinate region is defined for object image data to create a divided region, and parallel processing is performed along such coordinates.

  The invention according to claim 2 of the present application is the image forming apparatus according to claim 1, wherein the image processing unit calculates the number of colors for each of the divided image data to be counted using the parallel processing unit. It is characterized by comprising color number calculation means for adding up to the count color number of the entire image.

  The invention according to claim 3 of the present application is the image forming apparatus according to claim 1 or 2, wherein the image data dividing unit detects the image size detected by the image size detecting unit in the division determining unit. Is determined to exceed the preset image size threshold, the object image data is divided into a predetermined number.

  An invention according to claim 4 of the present application is the image forming apparatus according to any one of claims 1 to 3, wherein the image data dividing unit is based on an image size detected by the image size detecting unit. The number of image divisions is changed.

  The invention according to claim 5 of the present application is the image forming apparatus according to any one of claims 1 to 4, wherein the image processing unit is detected by the image size detection unit in the division determination unit. When it is determined that the image size does not exceed the image size threshold, the number of colors of the object image data is counted without dividing the object image data.

In addition, the invention according to claim 6 of the present application is the image forming apparatus according to any one of claims 1 to 5 , wherein the image processing unit has exceeded the preset color number threshold when the number of counted colors exceeds the preset value. The color number counting operation is interrupted at the time.

The invention according to claim 7 of the present application is the image forming apparatus according to any one of claims 1 to 6 , wherein the image processing unit is configured to set a color number threshold value in which a count color number after counting is set in advance. If it is determined that the value does not exceed the color material amount, the color material amount is reduced.

According to the invention of claim 1 of the present application, the image processing unit having the color material amount reduction determination unit determines whether to divide the object image data into a predetermined number based on the detection result of the size of the object image data. However, when the object image data is divided into a predetermined number from the determination result, the color number counting process is performed in parallel for each divided image data, and therefore, more efficient processing than counting the number of colors of the entire image is obtained. Therefore, it is possible to maintain the user's request for the output image with higher speed processing, or to reduce the cost.
In addition, the image processing unit does not reduce the color material amount when it is determined that the counted number of colors after the count exceeds a preset color number threshold value. Through the determination, the user's request for the output image can be maintained after waiting for more appropriate processing.

  According to the second aspect of the present invention, since the image processing unit sums the number of colors for each divided image data to obtain the count color number of the entire image, it is easy to obtain the number of colors of the entire image. Thus, the number of colors of the entire image can be obtained by such means, and image processing can be easily performed.

  According to the invention of claim 3 of the present application, the image processing unit divides the object image data into a predetermined number when it is determined that the detected image size exceeds a preset image size threshold. Therefore, the desired high-speed image processing can be realized by performing the division processing only on the image data having a large image size and requiring the division processing.

  According to the invention of claim 4 of the present application, the image processing unit changes the number of image divisions based on the detected image size, so that high-speed image processing according to the size of the image size can be realized.

  According to the invention of claim 5 of the present application, the image processing unit does not divide the object image data when it is determined that the detected image size does not exceed a preset image size threshold. Since the number of colors of the object image data is counted, it is possible to perform image processing after waiting for more appropriate processing without performing wasteful image division on image data having a small image size and that does not require division processing.

According to the invention of claim 6 of the present application, the image processing unit interrupts the color number counting operation when the number of counted colors exceeds the preset color number threshold. The processing time can be shortened without counting, and the user's request for the output image can be maintained with appropriate and high-speed processing.

According to the seventh aspect of the present invention, when the image processing unit determines that the number of counted colors after counting does not exceed a preset color number threshold, the color material amount is reduced. By determining whether to divide the image data, it is possible to reduce the cost of the color material amount after waiting for more appropriate processing.

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to the present invention, FIG. 2 is a diagram showing object image data received by the image forming apparatus according to the present invention, and FIG. 3 is a diagram of FIGS. FIG. 4 is a flowchart showing the image processing procedure of the image forming apparatus according to the present invention.

  As shown in FIG. 1, an image forming apparatus 1 according to the present invention is connected to an image input device 2 such as a host computer, and includes an image processing unit 10, a CPU 30, a hard disk drive (HDD) 40, a RAM 50, A ROM 60, an operation panel 70, and an image output unit 80 are provided.

  Except for the image processing unit 10, the configuration is the same as the normal configuration. The input result received from the image input device 2, that is, the image processing unit 10 performs image processing on the object image data via the CPU 30, and then the image output unit 80 Print out. Here, the image processing unit 10 describes position information such as characters and graphics, format information, and the like in PDL (page description language), creates a bitmap image, and performs image processing. Image processing is performed in the PDL state. May be converted to a bitmap image at the time of output. As PDL, Post Script (registered trademark name) is typical, but other PDL may be used. In this embodiment, the image forming apparatus 1 is described as a printer connected to a personal computer or the like, but may be a copying machine.

  The image processing unit 10 includes an image data receiving unit 11, an image size detecting unit 12, a division determining unit 13, an image data dividing unit 14, a parallel processing unit 15, a color number counting unit 16, and a color number calculating unit. 17, a message transmission unit 18, a color material amount reduction determination unit 19, a color conversion processing unit 20, a color material amount reduction execution unit 21, and a BMP (bitmap) image conversion unit 22.

  First, the image processing unit 10 receives object image data input from the image input device 2 at the image data receiving unit 11 and starts reading image data to be printed. As this starting means, a start button or the like in the operation unit 71 of the operation panel 70 can be considered, but it may be provided in the program of the image input apparatus 2. In addition to photographic images taken with a digital camera, the image data is various such as an office document read by a copying machine, a figure or the like pasted on the document data in an image format such as a bitmap. The object image data is not limited to image data, and may be vector data such as characters and figures.

  After the image data receiving unit 11 receives the object image data, the image size detecting unit 12 detects the image size in order to determine whether to divide the image data. The division determination unit 13 determines whether the image should be divided from the detected image size and a predetermined image size threshold, and the image data division unit 14 divides the image. The predetermined image size threshold value may be recorded in the HDD 40 as variable by the user, or may be stored in the ROM 60 as unchanged.

  For example, in color bitmap data, the object image data shown in FIGS. 2A and 2B is 507 KB (kilobytes), respectively, while shown in FIGS. 2C and 2D. It is assumed that each object image data is 1,110 KB (= 1.11 MB (megabyte)). Here, if the image size threshold is defined as 1,000 KB (= 1 MB), FIGS. 2A and 2B are smaller than the threshold, and FIGS. 2C and 2D exceed the threshold. Will be. Therefore, it is determined that the image is not divided in FIGS. 2A and 2B which are lower than the image size threshold, and conversely, FIGS. 2C and 2B which are higher than the image size threshold. In d), it is determined to divide the image.

  In the sizes shown in FIGS. 2C and 2D, since it is determined that the image is to be divided, the image data is divided. FIG. 3A shows a diagram obtained by dividing FIG. 2C into four parts, and FIG. 3B shows a diagram obtained by dividing FIG. 2D into four parts. Although the number of divisions is four in FIG. 3, the number of divisions is not limited to four, and other division numbers are also conceivable, and the number of image divisions can be changed according to the image size. Furthermore, the form of division may be equally divided vertically or horizontally, and the form is not limited to that shown in FIG.

  The divided image data is detected by the parallel processing unit 15 in units of divided images. Each detected divided image counts the number of colors in parallel by the color number counting unit 16. 3A and 3B show the divided image units (1) to (4), and parallel image processing, that is, the number of colors, as processing 1, processing 2, processing 3 and processing 4, respectively. Count.

  Note that the color number counting unit 16 can stop counting the number of colors when a predetermined color number threshold is exceeded, but the color of each divided image is being counted even when the number of colors for each divided image unit is being counted. It may be in the process of obtaining the sum of the numbers by the color number calculation unit 17. As a result, it is possible to stop counting the number of colors when the color number threshold is exceeded in the color number count for each divided image unit, and it is possible to stop the image processing without going through the color number calculation process. Image processing can be realized. In such a case, when the color number threshold is exceeded, the message transmission unit 18 transmits a color count stop message to the CPU 30, and the CPU 30 performs color number counting or color number calculation to the color number counting unit 16 or the color number calculation unit 17. Send a stop command. For example, when the color number threshold is set to 1,000 colors, even if the number of colors in processes 1 to 3 is 800 in FIG. 3A, the number of colors in process 4 exceeds the color number threshold. When the 1,001th color is counted, the count of process 4 is stopped. Note that a message to stop counting the number of colors may be displayed on the display unit 72.

  The number-of-colors calculation unit 17 calculates the total number of colors of each divided image. In this case, overlapping colors may exist in the area of each divided image unit. In this case, the overlap of colors may be ignored and the total sum may be simply obtained, but a certain color in one divided area is a processable range, and an overlapping color in another divided area is an unprocessable range, It is also possible to avoid duplication calculation by not counting the unprocessable range of colors or excluding them from the total number of colors.

  The color material amount reduction determination unit 19 determines whether the color material amount should be reduced from the color number threshold value recorded in the HDD 40 or the ROM 60 and the color number counted by the color number count unit 16. Such determination may be performed based on the number of colors for each divided image unit, or may be performed based on the number of colors of the entire image after the total number of colors of each divided image is obtained by the color number calculation unit 17. As a result, when it is determined that at least one of the color number counts for each divided image unit has already exceeded the color number threshold value, the number of colors is calculated without waiting for processing in other units. It is possible to determine whether or not to reduce the color material amount without going through the above, and it is possible to realize faster image processing. The color number threshold may be recorded in the HDD 40 as variable by the user, or may be stored in the ROM 60 as unchanged.

When the determination result of the color material amount reduction determination unit 19 indicates that the color material amount is to be reduced, the message transmission unit 18 transmits a color material amount reduction execution message to the color conversion processing unit 20, Color conversion is performed using a reduction LUT (lookup table). Then, a required color material amount is calculated from the color conversion result of the color conversion processing unit 20, and transfer is performed based on the color material amount. Since the image data is thinned by the color conversion process, the amount of required color material is inevitably reduced, and as a result, the amount of color material is reduced. The degree of reduction of the color material amount may be arbitrarily changed by the user, or may be a preset amount.
On the other hand, when it is determined that the color material amount is not reduced, the message transmitting unit 18 transmits a message indicating that the color material amount is not reduced to the color conversion processing unit 20, and a normal LUT (Look Up Table). Use to convert the color. After the color conversion, the BMP image conversion unit 22 creates output data that has undergone bitmap development, and the image output unit 80 performs printing.

  Next, an image processing procedure of the image forming apparatus according to the embodiment will be described with reference to the flowchart of FIG.

  First, after the image processing is started, the object image data received by the image data receiving unit 11 is read, and in step S1, the BMP image converting unit 22 converts the PDL data into BMP image data. The object size of the BMP converted object image data is detected using the image size detection unit 12 in step S2. After detecting the image size, the division determination unit 13 determines whether the image size exceeds the image size threshold in step S3.

  If it is determined in step S3 that the image size threshold has been exceeded, image data is divided using the image data dividing unit 14 in step S4. When each of the divided image data is detected by the parallel processing unit 15, the number of colors is counted in parallel using the color number counting unit 16 in step S5 for each of the divided image data.

  In step S5, the number of colors of each divided image data is counted, and in step S6, it is determined whether even one of the divided areas of the image data exceeds the color number threshold. As a result of the determination, if any one exceeds the color number threshold value, the color number count in the other divided areas is stopped in step S7, and the message transmission unit 18 transmits a count stop message. The reduction determination unit 19 indicates that the color material amount is not reduced. In step S14, image data is output from the image output unit 80 without reducing the color material amount. After the output is completed, the image processing ends.

  If it is determined in step S6 whether any one of the divided areas of the image data exceeds the color number threshold value, and if none of the divided color areas exceeds the color number threshold value, all of the divided areas are determined in step S8. It is determined whether the color count has been completed.

  If it is determined in step S8 that all the counts have been completed, the total number of colors in each divided area is calculated by the color number calculation unit 17 in step S9. Then, it is determined whether the total number of colors obtained by calculation in step S10 exceeds the color number threshold.

  If it is determined in step S8 that all the counts have not been completed, the color number counting unit 16 continues to count the number of colors, and the process returns to step S6 again to check whether any color number threshold has been exceeded. Judgment is made.

  When it is determined in step S10 that the total number of colors exceeds the color number threshold, the color material amount reduction determination unit 19 determines that the color material amount is not reduced, and in step S14, the color material amount is not reduced. Image data is output from the image output unit 80 without reducing the amount of material. After the output is completed, the image processing ends.

  When it is determined in step S10 that the total number of colors does not exceed the color number threshold, the color material amount reduction determination unit 19 determines that the color material amount is reduced, and in step S13, the color material is determined. The amount of color material is reduced using the amount reduction execution unit 21. After the reduction of the color material amount, image data is output from the image output unit 80 in step S14. After the output is completed, the image processing ends.

  On the other hand, if it is determined in step S3 that the image size has not been exceeded, the image data is not divided, and the number of colors of the entire object image is counted using the color number counting unit 16 in step S11. The In step S12, it is determined whether the number of colors of the entire image exceeds the color number threshold.

  If it is determined in step S12 that the color number threshold has been exceeded, image data is output from the image output unit 80 without reducing the amount of color material in step S14. After the output is completed, the image processing ends.

  When it is determined in step S12 that the color number threshold is not exceeded, the color material amount reduction determination unit 19 determines that the color material amount is reduced, and in step S13, the color material amount reduction execution unit 21 The amount of color material is reduced by using. After the reduction of the color material amount, image data is output from the image output unit 80 in step S14. After the output is completed, the image processing ends.

  Although not shown in FIG. 4, when the user selects to cancel the image processing via the operation unit 71, the image processing ends without outputting the image data.

  Note that the method of determining whether to reduce the color material amount is based on the difference in the appeal of the image to the user depending on the number of colors. That is, for example, photographers photographed with a digital camera are generally output without degrading image quality, and there is a strong demand from photographers to increase appeal and impact to users. When the amount of color material is uniformly reduced as described above for such image data, the photographic image loses sharpness, the boundary line of each object becomes ambiguous, and the entire image is blurred. turn into. As described above, it can be said that the image data such as a photograph that is generally required to have a high image quality is not convenient for the user. On the other hand, objects such as graphics pasted on document data in the form of an image such as a bitmap, for example, an object such as a graph, need only have a minimum image quality that can distinguish colors as a graph. . Therefore, even if the color material amount is reduced and the color becomes slightly lighter, it cannot be said that it is not convenient for the user. However, the determination method of the color material amount reduction is not limited to this, and other determination methods can be included.

  Further, as described above, in the embodiments of the invention of the image forming apparatus according to the present invention, a printer connected to a personal computer or the like has been shown. However, this printer may be an ink jet type or a laser type, Such an image copying apparatus may be used. As the image detection means, the image division means, the number of colors counting means, and the color material amount reduction means, known means can be used.

1 is a block diagram showing a configuration of an image forming apparatus according to the present invention. FIG. 4 is a diagram showing object image data received by the image forming apparatus according to the present invention. The figure which shows the state which divided the image data in FIG.2 (c) and FIG.2 (d) into 4 parts. 3 is a flowchart showing an image processing procedure of the image forming apparatus according to the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image input device 10 Image processing part 11 Image data receiving part 12 Image size detection part 13 Division determination part 14 Image data division part 15 Parallel processing part 16 Color number counting part 17 Color number calculation part 18 Message transmission part 19 Color material amount reduction determination unit 20 Color conversion processing unit 21 Color material amount reduction execution unit 22 BMP image conversion unit 30 CPU
40 HDD
50 RAM
60 ROM
70 Operation panel 80 Image output section

Claims (7)

An image forming apparatus including an image processing unit that performs color number count processing of object image data and determines whether or not to reduce the color material amount based on the counted color number, and can perform adjustment of the color material amount.
The image processing unit
And an image size detecting means for detecting the size of the object image data,
Based on the detection result by the image size detecting means, and determining division decision unit configured to determine whether to split the object image data into a predetermined number,
Image data dividing means for dividing the object image data into a predetermined number from the determination result by the division determination unit,
The image data divided by the image data dividing means, and parallel processing means divided parallel to each of the image data performed the color number count process,
Bei to give a,
The image forming apparatus , wherein the image processing unit does not perform color material reduction when it is determined that the counted number of colors after counting exceeds a preset color number threshold .   The image processing unit includes color number calculation means that adds the number of colors for each of the divided image data to be counted using the parallel processing means to obtain the counted number of colors for the entire image. The image forming apparatus according to claim 1.   The image data dividing unit sets the object image data to a predetermined number when the division determining unit determines that the image size detected by the image size detecting unit exceeds a preset image size threshold. The image forming apparatus according to claim 1, wherein the image forming apparatus is divided.   The image forming apparatus according to claim 1, wherein the image data dividing unit changes the number of image divisions based on the image size detected by the image size detecting unit.   If the image processing unit determines that the image size detected by the image size detection unit does not exceed the image size threshold value, the image processing unit does not divide the object image data. The image forming apparatus according to claim 1, wherein the number of colors is counted. The image forming apparatus according to claim 1, wherein the image processing unit interrupts a color number counting operation when the counted number of colors being counted exceeds a preset color number threshold. .   7. The image processing unit according to claim 1, wherein the image processing unit executes a reduction in the amount of color material when it is determined that the counted number of colors after counting does not exceed a preset color number threshold. The image forming apparatus according to any one of the above.

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