JP2016032263A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation apparatus capable of automatically determining whether or not two-color printing is carried out, when reading a document as a color image and printing that image.SOLUTION: A document reading unit 200 reads a document as a color image, and generates image data representing the image of the document. A first calculation unit 501 calculates the size of the color area of the document, on the basis of the image data generated by the document reading unit 200. A first determination unit 503 determines whether or not the size of the color area, calculated by the first calculation unit 501, is smaller than a predetermined first threshold. When a determination is made by the first determination unit 503 that the size of the color area, calculated by the first calculation unit 501, is smaller than the first threshold, a control unit 500 controls a print section 100 to carry out a print job by two-color printing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus having a two-color printing function.

  In two-color printing, an image is printed by selecting two colors (for example, one color other than black and black) from a plurality of colors (for example, cyan, magenta, yellow, and black) that constitute the color. It is. Two-color printing can reduce the amount of toner consumed as compared with full-color printing, and can improve appeal and expressive power compared with monochrome printing. In many cases, the user of the image forming apparatus has a support contract charged for the number of printed sheets. The charge per sheet for two-color printing is usually set lower than that for full-color printing. For this reason, the two-color printing is beneficial to the user because it can reduce the cost.

  The two-color copy is a copy using two-color printing, in which an original is read as a color image and the image is printed in two colors.

  As a technology relating to two-color copying, a reading unit that reads an image of a document and outputs image data, and color information of the image data output from the reading unit determines whether a full-color document, a black document, or a two-color document. An image forming apparatus is proposed that includes a determination unit that performs switching, and a control unit that controls switching between image processing and printing operation of the image data in accordance with a determination result of the determination unit (for example, a patent). Reference 1).

JP 2007-97169 A

  The user has selected a two-color copy, but the printed image is uncomfortable (in other words, the image looks worse than expected), so the same document may be full-color copied. In particular, if the user has little knowledge of two-color copying, the possibility is high. As described above, the user may make a mistake in selecting between the two-color copy and the full-color copy, and thus may be at a loss in selecting between the two-color copy and the full-color copy.

  Further, when the user selects the two-color copy and the full-color copy, the user wants to select the two-color copy in order to reduce the toner consumption and the cost, but forgets to select the two-color copy and the full-color copy is made. Sometimes.

  An object of the present invention is to provide an image forming apparatus that can automatically determine whether or not two-color printing is performed when a document is read as a color image and the image is printed.

  An image forming apparatus according to the present invention that achieves the above object reads a document as a color image and generates image data indicating an image of the document, and the image data generated by the document reading unit. The first calculation unit that calculates the size of the color area of the document, and the size of the color area calculated by the first calculation unit is based on a predetermined first threshold value. A first determination unit that determines whether the image is small; a printing unit that executes a print job for printing an image of the document indicated by the image data generated by the document reading unit; and the first determination unit And a control unit that causes the printing unit to execute the print job by two-color printing when it is determined that the size of the color area is smaller than the first threshold value.

  The present invention focuses on the fact that if the color area of the original is small, even if the original image is printed in two colors, the image is less uncomfortable and the appearance of the image is not much different from full color printing. The color area is a portion expressed in a chromatic color in the document. According to the image forming apparatus of the present invention, when the size of the color area of the document is smaller than the predetermined first threshold value, the image of the document is printed in two colors. Therefore, when the original is read as a color image and the image is printed, it can be automatically determined whether or not to print two colors. The first threshold value is determined from the above viewpoint. For example, when an A4 document has a color area smaller than 30 mm square, two-color printing is performed.

  In the above configuration, when the size of the color area is determined to be greater than or equal to the first threshold by the first determination unit, the size of the color area is larger than the first threshold. A second determination unit configured to determine whether or not the second threshold value is greater than a predetermined second threshold value; and the control unit is configured so that the size of the color area is determined by the second determination unit. When it is determined that the value is larger than the threshold value, the printing unit is caused to execute the print job by the full-color printing, and the image of the document is configured based on the image data generated by the document reading unit. When the second calculation unit that calculates the number of colors and the second determination unit determine that the size of the color area is equal to or less than the second threshold value, the number of colors is determined in advance. Greater than the third threshold A third determination unit that determines whether the number of colors is greater than the third threshold value by the third determination unit, and the printing unit When the print job is executed in the full color printing and the number of the colors is determined to be equal to or less than the third threshold value by the third determination unit, Run a print job.

  In this configuration, attention is paid to the fact that the number of colors constituting the image of the document in addition to the area of the color area of the document causes a sense of incongruity in the image in two-color printing. If the color area is small, the sense of incongruity of the image is small even with two-color printing, regardless of the number of colors that make up the image of the document. On the other hand, if the color area is large, two-color printing will cause the image to be uncomfortable regardless of the number of colors constituting the original image. Also, if the color area is not small and not large, if the number of colors constituting the original image is small, the sense of incongruity of the image is small even with two-color printing, and the color constituting the original image is small. If the number is large, the image feels uncomfortable when two-color printing is performed.

  Therefore, according to this configuration, when the color area is small, two-color printing is executed regardless of the number of colors constituting the original image, and when the color area is large, the number of colors constituting the original image. Regardless of whether or not full-color printing is performed. When the color area is neither small nor large, two-color printing is executed if the number of colors constituting the original image is small, and full color printing is performed if the number of colors constituting the original image is large. Run.

  In the above configuration, the second calculation unit divides each gradation range of a plurality of colors representing a color into a plurality of parts, regards gradations belonging to the same division range as the same, and each of the plurality of colors. A setting unit that sets a plurality of areas defined by the division range, and a count of which of the plurality of areas each of the pixels constituting the image of the document belongs to, and the plurality of areas A creation unit that creates a histogram indicating the number of pixels belonging to each of the first region, a first region having a smaller number of pixels than a predetermined number of the plurality of regions, with reference to the histogram, and an achromatic color The number of pixels in the second region indicating 0 is regarded as 0, the remaining regions other than the first region and the second region are compared with each other, and the number of pixels in the continuous region is one. More areas than Considers the number of pixels in the region between 0 comprises, a determination unit that the number of regions the number of pixels is not zero, it is determined that the number of the color among the plurality of regions.

  This configuration is an example of a method for calculating the number of colors composing the document image.

  In the configuration described above, an operation for setting a mode for automatically selecting either the full-color printing or the two-color printing is performed on the image of the document indicated by the image data generated by the document reading unit. An operation unit is further provided, and the first calculation unit calculates the size of the color area on the condition that the mode is set, and the first determination unit calculates the size of the color area. Is determined to be smaller than the first threshold, the second calculation unit calculates the number of colors, and the second determination unit determines that the size of the color area is the It is determined whether or not it is greater than a second threshold value, and the third determination unit determines whether or not the number of colors is greater than the third threshold value.

  According to this configuration, when the user performs an operation of selecting a mode for automatically selecting either full-color printing or two-color printing, either full-color printing or two-color printing is automatically performed. Selected.

  According to the present invention, it is possible to provide an image forming apparatus that can automatically determine whether or not two-color printing is performed when a document is read as a color image and the image is printed.

1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. 3 is a first flowchart for explaining the operation of the image forming apparatus according to the embodiment. 6 is a second flowchart illustrating the operation of the image forming apparatus according to the present embodiment. In the first axis, the second axis, and the third axis orthogonal to each other, the cyan gradation is the first axis, the magenta gradation is the second axis, and the yellow gradation is the third axis. It is explanatory drawing explaining a color model. It is a schematic diagram which shows the outline | summary of an example of the histogram which the 2nd calculation part produced | generated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 will be described by taking a digital multifunction machine having functions of a copy, a printer, a scanner, and a facsimile as an example. The image forming apparatus 1 may be an apparatus having a color copy function, and is not limited to a digital multifunction peripheral. For example, a color copier may be used as the image forming apparatus 1. The image forming apparatus 1 includes a printing unit 100, a document reading unit 200, a document feeding unit 300, an operation unit 400, a control unit 500, and a communication unit 600.

  When a single document is placed on the document placement unit provided in the document feed unit 300, the document feed unit 300 sends the document to the document reading unit 200, and a plurality of documents are placed on the document placement unit. When an original is placed, a plurality of originals are continuously sent to the original reading unit 200.

  The document reading unit 200 reads a document placed on a document table or a document fed from the document feeding unit 300 and outputs image data of the document. The document reading unit 200 has a color scanning function, reads a document as a color image, and generates image data indicating an image of the document.

  The printing unit 100 executes a print job. A print job refers to an image indicated by data indicating data (for example, image data output from the document reading unit 200, print data transmitted from a personal computer (not shown), image data received by facsimile). This is a job for generating a printed matter.

  The operation unit 400 includes an operation key unit 401 and a display unit 403. The display unit 403 has a touch panel function, and displays a screen including soft keys. The user operates the soft key while viewing the screen to make settings necessary for executing functions such as copying.

  The operation key unit 401 is provided with operation keys including hard keys. The operation key is, for example, a function switching key for switching between a start key, a numeric keypad, a reset key, a copy, a printer, a scanner, and a facsimile.

  The control unit 500 includes a CPU, a ROM, and a RAM. The CPU executes control necessary for operating the image forming apparatus 1 on the above-described components (for example, the printing unit 100) of the image forming apparatus 1. The ROM stores software necessary for controlling the operation of the image forming apparatus 1. The RAM is used for temporary storage of data generated during execution of software, storage of application software, and the like.

  The control unit 500 includes a first calculation unit 501, a first determination unit 503, a second calculation unit 505, a second determination unit 507, and a third determination unit 509 as functional blocks. Details of these blocks will be described later.

  The communication unit 600 includes a facsimile communication unit 601 and a network I / F unit 603. The facsimile communication unit 601 includes an NCU (Network Control Unit) that controls connection of a telephone line with a destination facsimile and a modulation / demodulation circuit that modulates / demodulates a signal for facsimile communication. The facsimile communication unit 601 is connected to the telephone line 605.

  The network I / F unit 603 is connected to a LAN (Local Area Network) 607. A network I / F unit 603 is a communication interface circuit for executing communication with a terminal device such as a personal computer connected to the LAN 607.

  The originals to be copied include originals expressed only with achromatic colors and other originals. The former is called a monochrome manuscript. The latter is called a color manuscript and is a manuscript including a color area (that is, a portion expressed in chromatic colors).

  Even if it is a color manuscript, if the number of colors constituting the manuscript image is small (for example, a manuscript containing a red imprint in a monochrome document, a manuscript containing a blue corporate mark in the header or footer, or a monochrome document) Documents containing characters highlighted in red) Even if two-color copying is performed, the image is less uncomfortable and the appearance of the image is not much different from that of a full-color copy. Such a document is useful for the user because if the two-color copy is made without performing the full-color copy, the toner consumption is small and the charge is small.

  However, even a color document with a small number of colors constituting an image of the document, if the area of the color area is large, if two-color copying is performed, the image is uncomfortable and the appearance of the image is significantly different from the expected one. There is. For example, when a two-color copy of a document that is mostly a blue photograph is copied, the blue photograph is expressed in a color other than blue, so that the image becomes uncomfortable.

  Even if a color manuscript with a large number of colors composing the original image, if the area of the color area is small, even if two-color copying is performed, the image does not feel uncomfortable, and the appearance of the image is much different from a full-color copy. Absent. For example, if a document is mainly composed of a monochrome document and part of a color region composed of a large number of colors, even if two-color copying is performed, the image does not feel strange.

  As described above, two-color copying is performed without performing full-color copying according to the size of the color area in the document and the number of colors constituting the image of the document (in other words, the colors constituting the color area). There are cases where it is acceptable and cases where full color copying is required. The image forming apparatus 1 according to the present embodiment automatically determines whether or not to perform two-color copying based on the size of the color area of the document and the number of colors constituting the document image.

  The operation of the image forming apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 to 3 mainly using a single-sided copy of one original as an example. 2 and 3 are flowcharts for explaining the operation.

  The user sets a document on the document reading unit 200 or the document table (not shown), and operates the operation unit 400 to make settings necessary for copying (step S1). This includes a setting for selecting one of a color copy mode, a monochrome copy mode, and an ACS (Auto Color Select) mode in addition to the setting of the number of copies and the paper size.

  In the ACS mode, the control unit 500 determines whether or not a document to be copied is a color document. If the document is determined to be a color document, the color copy mode is selected. If the document is determined not to be a color document, the monochrome copy mode is set. .

  In the color copy mode, full-color copy or two-color copy is executed. In the monochrome copy mode, monochrome copy is executed.

  The full color copy is to copy a document using a plurality of colors (for example, cyan, magenta, yellow, and black) constituting the color. The two-color copy is to copy a document by selecting two colors (for example, one color other than black and black) from a plurality of colors constituting the color. Monochrome copying is copying a document using black.

  The control unit 500 determines whether the start key of the operation key unit 401 is pressed in a state where the document is set on the document reading unit 200 or the document table (not shown) (step S2). When control unit 500 determines that the start key is not pressed (No in step S2), the process of step S2 is repeated.

  When the control unit 500 determines that the start key has been pressed (Yes in step S2), the control unit 500 causes the document reading unit 200 to read the document as a color image, and the document reading unit 200 displays the image of the document. Image data is generated (step S3). Since one-sided copy of one original, one page of image data is generated.

  The controller 500 determines whether or not the color copy mode is selected in step S1 (step S4). When the control unit 500 determines that the color copy mode is not selected (No in step S4), the control unit 500 determines whether the ACS mode is selected in step S1 (step S5).

  When the control unit 500 determines that the ACS mode is not selected (No in step S5), that is, when it is determined that the monochrome copy mode is selected in step S1, the control unit 500 generates in step S3. The print unit 100 is caused to execute a print job for monochrome printing the image indicated by the image data (step S6).

  When the control unit 500 determines that the ACS mode is selected (Yes in step S5), the control unit 500 uses the image data generated in step S3 to determine that the document to be copied is a color document. It is determined whether the document is a document (step S7). The control unit 500 makes the determination using a general ACS method.

  When the control unit 500 determines that the document to be copied is not a color document (No in step S7), the control unit 500 enters a monochrome copy mode. Thereby, the control unit 500 causes the printing unit 100 to execute a print job for monochrome printing the image indicated by the image data generated in step S3 (step S6).

  When the control unit 500 determines that the document to be copied is a color document (Yes in step S7), or when it is determined that the color copy mode is selected in step S1 (Yes in step S4), the control is performed. The unit 500 determines whether or not the saving copy mode is set (step S8). In the saving copy mode, in the color copy mode, two-color copying is executed if the original to be copied satisfies a predetermined condition, and full-color copying is executed if the predetermined condition is not satisfied.

  In the saving copy mode, the user can set and cancel the setting by operating the operation unit 400. If the user is requested to set the saving copy mode for each copy, the user may forget to set the copy mode. For this reason, in this embodiment, the saving copy mode is set by default.

  The saving copy mode is a mode in which either full-color printing or two-color printing is automatically selected for the document image indicated by the image data generated by the document reading unit 200. The user can set the mode by operating the operation unit 400.

  When the control unit 500 determines that the copy mode is not the saving copy mode (No in step S8), the control unit 500 executes a print job for performing full color printing on the image indicated by the image data generated in step S3. (Step S9).

  When the control unit 500 determines that the copy mode is the saving copy mode (Yes in step S8), the first calculation unit 501 determines the size of the color area of the document based on the image data generated in step S3. Calculate (step S10). This will be described in detail.

  The first calculation unit 501 obtains the saturation of each pixel constituting the color image indicated by one page of image data generated in step S3 using, for example, Expression 1 shown below.

Saturation: MAX (C, M, Y) −MIN (C, M, Y)... Formula 1
When the saturation is greater than a predetermined threshold value T1, the first calculation unit 501 determines that the pixel is a color pixel. For each pixel, for example, it is assumed that cyan, magenta, and yellow are each expressed with 8-bit gradation. The threshold value T1 is, for example, any value in the range of 20 to 30, but is not limited thereto.

  For example, in a certain pixel, the gradation of cyan is 0, the gradation of magenta is 30, and the gradation of yellow is 150. MAX (0, 30, 150) is 150, and MIN (0, 30, 150) is 0. Therefore, the saturation of the pixel is 150. Since the saturation of this pixel is greater than the threshold value T1, this pixel is a color pixel.

  The first calculation unit 501 determines whether or not all of the pixels constituting the color image indicated by the image data of one page are color pixels, and then counts the number of color pixels to obtain the total number of color pixels. The value is the size of the color area of the document.

  The size of the color area will be specifically described by taking the document size as A4 and the resolution as 600 dpi as an example. When the document size is A4 and the resolution is 600 dpi, the number of pixels is 35000000 (= about 7000 × about 5000). When the total value of the color pixels is 518400, the size of the color area of the document is about 30 mm square. When the total value of the color pixels is 17500000, the size of the color area of the document is half that of the document.

  The first determination unit 503 determines whether the size of the color area calculated in step S10 is smaller than a predetermined threshold value T2 (step S11). The threshold value T2 is a first threshold value. If the area of the color area of the original is small, even if two-color copying is performed, the image does not feel strange, and the appearance of the image is not much different from the full-color copying. It is determined from. In the present embodiment, the above-mentioned 518400 is set as the threshold value T2, but the threshold value T2 is not limited thereto.

  When the first determination unit 503 determines that the size of the color area is smaller than the threshold T2 (Yes in step S11), the control unit 500 performs two-color printing of the image indicated by the image data generated in step S3. The print unit 100 is caused to execute a print job to be performed (step S12).

  When the first determination unit 503 determines that the size of the color area is equal to or greater than the threshold value T2 (No in step S11), the second determination unit 507 determines that the size of the color area calculated in step S10 is It is determined whether or not the threshold value is greater than T3. The threshold value T3 is a second threshold value and is larger than the threshold value T2. Since the area of the color area of the document is relatively large, the threshold value T3 is determined from the viewpoint of increasing the uncomfortable feeling of the image when performing two-color copying. In the present embodiment, the threshold value T3 is a value at which half of the original is the color area, but the threshold value T3 is not limited to this.

  When the second determination unit 507 determines that the size of the color area is larger than the threshold value T3 (Yes in step S13), the control unit 500 displays the image indicated by the image data generated in step S3. The printing unit 100 is caused to execute a print job for performing full color printing (step S9).

  When the second determination unit 507 determines that the size of the color area is equal to or less than the threshold value T3 (No in step S13), the second calculation unit 505 generates the one-page image generated in step S3. Based on the data, the number of colors (chromatic colors) constituting the image of the document to be copied is calculated (step S14). This will be described in detail.

  For example, if cyan, yellow, and magenta are expressed by, for example, 8-bit gradation, cyan, yellow, and magenta can be represented by information of 0 to 255, respectively. Therefore, there are about 16.77 million color combinations (= 256 × 256 × 256). However, since there are too many color combinations, 0 to 255 are equally divided into, for example, 16 in this embodiment, and the number of color combinations is 4096 (= 16 × 16 × 16).

  FIG. 4 shows a first axis, a second axis, and a third axis that are orthogonal to each other, the cyan gradation being the first axis, the magenta gradation being the second axis, and the yellow gradation being the third axis. It is explanatory drawing explaining the color model made into an axis | shaft. In the first axis, the gradation is C (1) for a range of 0-15, C (2) for a range of 16-31, C (3) for a range of 32-47, and C for a range of 48-63. (4), the range of 64-79 is C (5), the range of 80-95 is C (6), the range of 96-111 is C (7), the range of 112-127 is C (8), 128- The range of 143 is C (9), the range of 144 to 159 is C (10), the range of 160 to 175 is C (11), the range of 176 to 191 is C (12), the range of 192 to 207 is C ( 13), 208 to 223 is C (14), 224 to 239 is C (15), and 240 to 255 is C (16).

  Similarly, on the second axis, the gradation is M (1) in the range of 0-15, M (2) in the range of 16-31, M (3) in the range of 32-47, and 48-63. The range is M (4), the range from 64 to 79 is M (5), the range from 80 to 95 is M (6), the range from 96 to 111 is M (7), the range from 112 to 127 is M (8) The range of 128 to 143 is M (9), the range of 144 to 159 is M (10), the range of 160 to 175 is M (11), the range of 176 to 191 is M (12), the range of 192 to 207 Is M (13), 208-223 is M (14), 224-239 is M (15), and 240-255 is M (16).

  In the third axis, the gradation is Y (1) in the range from 0 to 15, Y (2) in the range from 16 to 31, Y (3) in the range from 32 to 47, and Y in the range from 48 to 63. (4), the range from 64 to 79 is Y (5), the range from 80 to 95 is Y (6), the range from 96 to 111 is Y (7), the range from 112 to 127 is Y (8), 128 ~ The range of 143 is Y (9), the range of 144 to 159 is Y (10), the range of 160 to 175 is Y (11), the range of 176 to 191 is Y (12), the range of 192 to 207 is Y ( 13), 208 to 223 is Y (14), 224 to 239 is Y (15), and 240 to 255 is Y (16).

  4096 regions R of region R1 to region R4096 are defined by combinations of C (1) to C (16), M (1) to M (16), and Y (1) to Y (16). For example, the region R1 is defined by C (1), M (1), and Y (1). The region R2 is defined by C (2), M (1), and Y (1). The region R4096 is defined by C (16), M (16), and Y (16). Pixels belonging to the same region R are regarded as the same color.

  The above processing is executed by the setting unit 511 included in the second calculation unit 505. That is, the setting unit 511 divides each gradation range of a plurality of colors representing a color into a plurality of parts, regards the gradations belonging to the same division range as the same, and is defined by each division range of the plurality of colors. A plurality of regions R are set. In the present embodiment, the plurality of colors representing the color are cyan, magenta, and yellow, the gradation range is 0 to 255, and the division is a plurality of 16 divisions. The same division range is, for example, C (1), and the plurality of regions R are 4096 regions R.

  Second calculation unit 505 further includes a creation unit 513 and a determination unit 515. The creation unit 513 includes a counter corresponding to each of the 4096 regions R, and each of all the pixels constituting the color image indicated by the image data of one page generated in step S3 includes 4096 regions. Counting which region of R belongs, a histogram indicating the number of pixels belonging to each of 4096 regions R is created. FIG. 5 is a schematic diagram showing an outline of an example of the histogram. The horizontal axis indicates the region R, and the vertical axis indicates the number of pixels.

  Of the 4096 regions R, the determination unit 515 sets the counter corresponding to the region R to 0 for the region R (first region) in which the number of pixels is smaller than a predetermined number (that is, the region). The number of pixels is assumed to be 0). In order to suppress the influence of noise or the like, a color with a small number of pixels is regarded as not a color.

  If the number of pixels belonging to the region R is smaller than a predetermined threshold value T4, the determining unit 515 determines that the region R has a small number of pixels. The threshold value T4 depends on the size of the document. For example, if the document size is A4 and the resolution is 600 dpi, the number of pixels constituting the color image indicated by the image data of one page generated in step S3 is 35000000 (= about 7000 × about 5000). The threshold value T4 is set to 1000, for example.

  Next, the determination unit 515 sets the counter corresponding to the region R to 0 (that is, sets the number of pixels in the region R to 0) for the region R (second region) indicating an achromatic color. Achromatic colors are considered not colors.

  For example, when the value represented by Equation 2 below is smaller than a predetermined threshold value T5, the region R is determined to be an achromatic color. The threshold value T5 is set to 1 or 2, for example, but is not limited thereto.

MAX (Cnum, Mnum, Ynum) -MIN (Cnum, Mnum, Ynum) Formula 2
Here, “num” indicates any one of (1) to (16). For example, in the region R2, MAX (C (2), M (1), Y (1)) is 2, and MIN (C (2), M (1), Y (1)) is 1. is there. Therefore, MAX (C (2), M (1), Y (1)) − MIN (C (2), M (1), Y (1)) = 1. Further, for example, the region R defined by C (1), M (4), Y (15) is MAX (C (1), M (4), Y (15))-MIN (C (1) , M (4), Y (15)) = 15-1 = 14.

  Next, the determination unit 515 determines the continuous regions R for the remaining regions R other than the region R (first region) with a small number of pixels and the region R (second region) indicating an achromatic color. In comparison, for the region R other than the region R having the largest number of pixels in the continuous region R, the counter corresponding to the region R is set to 0 (that is, the number of pixels in the region R is set to 0). . The continuous regions R are regarded as the same color, and the region R having a small number of pixels is thinned out.

  For example, the number of pixels in the region R1999 and the region R2002 is 0. The number of pixels in the region R2000 and the number of pixels in the region R2001 are compared, and the number of pixels in the region R2000 with a small number of pixels is set to zero.

  The determination unit 515 counts the number of counters indicating one or more values among the counters corresponding to each of the regions R1 to R4096, and determines the value as the number of colors. For example, if the number of counters showing a value of 1 or more (that is, the number of regions R where the number of pixels is not 0) is 1, the number of colors (chromatic colors) constituting the document image is one. This corresponds to a manuscript in which one color is added to black and white.

  The third determination unit 509 determines whether or not the number of colors calculated in step S14 is greater than a predetermined threshold value T6 (step S15). The threshold value T6 is the third threshold value. When the area of the color region is not small and not large (No in step S11, No in step S13), even if two-color copying is performed, the image It is determined from the viewpoint of not feeling uncomfortable. In the present embodiment, the threshold value T6 is set to 3, but the threshold value T6 is not limited thereto.

  When it is determined that the number of colors calculated in step S14 is larger than the threshold value T6 (Yes in step S15), the control unit 500 performs printing for full-color printing of the image indicated by the image data generated in step S3. The job is executed by the printing unit 100 (step S9).

  When it is determined that the number of colors calculated in step S14 is equal to or less than the threshold value T6 (No in step S15), the control unit 500 prints the image indicated by the image data generated in step S3 in two colors. The job is executed by the printing unit 100 (step S12).

  The main effects of this embodiment will be described. The present embodiment focuses on the fact that if the color area of the document is small, even if the image of the document is printed in two colors, the image is less uncomfortable and the appearance of the image is not much different from full color printing. According to the present embodiment, when the size of the color area of the document is smaller than the threshold value T2 (first threshold value) (Yes in step S11), the image of the document is printed in two colors (step S12). . Therefore, when the original is read as a color image and the image is printed, it can be automatically determined whether or not to print two colors.

  In the present embodiment, attention is paid to the fact that, in addition to the area of the color area of the document, the number of colors constituting the image of the document causes a great sense of discomfort in the image in two-color printing. If the color area is small, the sense of incongruity of the image is small even with two-color printing, regardless of the number of colors that make up the image of the document. On the other hand, if the color area is large, two-color printing will cause the image to be uncomfortable regardless of the number of colors constituting the original image. Also, if the color area is not small and not large, if the number of colors constituting the original image is small, the sense of incongruity of the image is small even with two-color printing, and the color constituting the original image is small. If the number is large, the image feels uncomfortable when two-color printing is performed.

  Therefore, when the color area is small (Yes in step S11), two-color printing is executed regardless of the number of colors constituting the original image (step S12), and when the color area is large (Yes in step S13). Then, full-color printing is executed regardless of the number of colors constituting the document image (step S9). When the color area is neither small nor large, if the number of colors constituting the document image is small (No in step S15), two-color printing is executed (step S12), and the document image is configured. If the number of colors is large (Yes in step S15), full-color printing is executed (step S9).

  As described above, according to the present embodiment, when copying a document including a color area (color document), either a full-color copy or a two-color copy is automatically selected according to the document. When the two-color copy is selected, it is possible to save toner consumption and billing while reducing the uncomfortable feeling of the copied image. When full-color copy is selected, the uncomfortable feeling of the copied image can be eliminated.

  Further, according to the present embodiment, as described in step S8, the saving copy mode is set by default. That is, the control unit 500 presets a mode for automatically selecting either full-color printing or two-color printing for the document image indicated by the image data generated by the document reading unit 200. Therefore, the user does not need to set the mode every time copying is performed.

1 Image forming apparatus R, R1, R2, R4096

Claims (4)

An original reading unit that reads an original as a color image and generates image data indicating the image of the original;
A first calculation unit that calculates the size of the color area of the document based on the image data generated by the document reading unit;
A first determination unit that determines whether the size of the color area calculated by the first calculation unit is smaller than a predetermined first threshold;
A printing unit that executes a print job for printing an image of the document indicated by the image data generated by the document reading unit;
A control unit that causes the printing unit to execute the print job by two-color printing when the size of the color area is determined to be smaller than the first threshold value by the first determination unit. Image forming apparatus. When the size of the color area is determined to be greater than or equal to the first threshold by the first determination unit, the size of the color area is determined in advance to be greater than the first threshold. A second determination unit that determines whether or not the second threshold value is greater than the second threshold;
The control unit causes the printing unit to execute the print job in the full-color printing when the second determination unit determines that the size of the color area is larger than the second threshold value.
A second calculating unit that calculates the number of colors constituting the image of the document based on the image data generated by the document reading unit;
When the second determination unit determines that the size of the color area is equal to or less than the second threshold value, it is determined whether the number of colors is greater than a predetermined third threshold value. And a third determination unit for determining,
When the third determination unit determines that the number of colors is greater than the third threshold, the control unit causes the printing unit to execute the print job in the full color printing, and 2. The image forming apparatus according to claim 1, wherein when the number of colors is determined to be equal to or smaller than the third threshold value by the three determination units, the print unit is caused to execute the print job by the two-color printing. The second calculation unit includes:
Dividing each gradation range of a plurality of colors representing a color into a plurality of areas, regarding gradations belonging to the same division range as the same, and defining a plurality of regions defined by each of the division ranges of the plurality of colors A setting section to be set;
A creation unit that counts which of the plurality of regions each of all pixels constituting the image of the document belongs to, and creates a histogram indicating the number of pixels belonging to each of the plurality of regions;
Referring to the histogram, among the plurality of regions, the first region having a number of pixels smaller than a predetermined number and the number of pixels in the second region showing an achromatic color are regarded as 0, and the first region And the remaining areas other than the second area are compared with each other, the number of pixels in the area other than the area with the largest number of pixels among the consecutive areas is regarded as 0, The image forming apparatus according to claim 2, further comprising: a determining unit that determines the number of areas in which the number of pixels is not 0 as the number of colors. An operation unit configured to perform an operation for setting a mode for automatically selecting either the full-color printing or the two-color printing for the image of the document indicated by the image data generated by the document reading unit; Prepared,
On condition that the mode is set, the first calculation unit calculates the size of the color area, and the first determination unit determines that the size of the color area is the first size. It is determined whether or not it is smaller than a threshold value, the second calculation unit calculates the number of colors, and the second determination unit determines that the size of the color area is the second threshold value. 4. The image forming apparatus according to claim 2, wherein the third determination unit determines whether or not the number of colors is larger than the third threshold value.

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