JP2005079750A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the printing of an image quite different from an image imagined by a user on a sheet of recording paper in the case of converting a color original into a monochromatic image. <P>SOLUTION: An image forming apparatus is provided with a character area extraction part 11 for extracting a character area from an original image read out by an original reading part 500, a color determination part 12 for judging the colors of respective characters constituting the character area, a color conversion part 13 for converting the colors of emphasized characters in accordance with the toner residues of respective colors, a monochromatic image conversion part 14 for converting the character area into a monochromatic image, a display image preparation part 15 for preparing a first original monochromatic image which is a monochromatic image of the original image, a second original monochromatic image which is a monochromatic image of the original image obtained by applying emphasis processing to emphasized characters, a first original color image, and a second original color image and displaying the thumbnail images of respective images on a touch panel 401, and an exposure control part 16 for receiving a selection command from the user through the touch panel 401 and printing the selected image. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that converts a color image into a monochrome image.

In color manuscripts mainly composed of sentences, in order to distinguish important characters in sentences from other characters, they are often displayed with emphasis using colors such as red. When a color original image is converted into a monochrome image using a conventional image forming apparatus, characters displayed with emphasis in red or the like (emphasized characters) are converted into gray shades and printed. . Therefore, depending on the relationship between the color of the emphasized character and the color of the background portion of the character, there is a problem in that the density of the two portions is close to each other and the visibility of the emphasized character is lowered. Therefore, in order to prevent a reduction in the visibility of the emphasized character converted into a monochrome image, the emphasized character is outlined or represented by black which is the maximum density, or the outline portion of the emphasized character is eliminated or A method of expressing the maximum density in black is disclosed (Patent Document 1).
JP 2002-252773 A (FIG. 3)

  However, according to the technique of Patent Document 1, a monochrome image that has been subjected to processing for preventing a reduction in visibility is printed without being presented to the user in advance, and thus is an image that is far from what the user imagines. Could be printed. Also, in an image forming apparatus capable of printing a color image, it may be better from the viewpoint of visibility or user preference to print the read color original image as it is than to print it as a monochrome image. Further, in the conventional apparatus, when a monochrome image that is far from what the user imagines is printed, it is necessary to print again, which is troublesome and wastes recording paper. It was.

  The present invention has been made to solve the above-described problem, and an image far from what a user imagines while preventing a decrease in the visibility of emphasized characters due to the conversion of a color document into a monochrome image. An object of the present invention is to provide an image forming apparatus that prevents printing on recording paper.

  In order to solve the above problems, an image forming apparatus according to the present invention is an image forming apparatus that forms a color image on recording paper using a plurality of toners each having a different color, and obtains an original image. Means, character area extracting means for extracting, as a character area, an area composed of pixels constituting a character based on the luminance of each pixel of the original image, and whether the character area is composed of characters of two or more colors A color determination unit that determines whether the character region is composed of characters of two or more colors, and a monochrome conversion unit that converts the character region into a monochrome image; Based on the monochrome image converted by the monochrome conversion means, a first original monochrome image that is a monochrome image of the original image is created, and the created original original monochrome image and the monochrome image are created. Image display means for displaying a first original color image, which is an original image that has not been converted into an image, on a display device, and printing either the first original monochrome image or the first original color image A selection receiving unit that receives the selection command, and a printing unit that prints an image defined by the selection command received by the selection receiving unit on a recording sheet.

  Further, the monochrome conversion means performs an emphasis process for notifying the conversion of characters converted to a monochrome image by a color different from the original color, and the image display means A second original monochrome image is created based on the monochrome image subjected to the enhancement processing by the conversion means, the created second original monochrome image is further displayed on the display device, and the selection receiving means It is preferable to accept selection of any one of the first original monochrome image, the second original monochrome image, and the first original color image to be printed.

  Moreover, it is preferable that the said emphasis process is a process which converts the character converted into the color different from the original color into a hollow character.

  Further, a toner remaining amount determining unit that determines whether or not the remaining amount of toner of each color is within a specified value, and the toner remaining amount determining unit among the characters constituting the character area extracted by the character region extracting unit Color conversion means for converting the color of a character printed by toner of a color determined to be equal to or less than a specified value by the toner into a color based on toner of a color determined to be larger than a specified value by the toner remaining amount determining means; The image display means creates a second original color image based on the character area converted by the color conversion means, and further displays the created second original color image on the display device. The selection receiving unit prints any one of the first original monochrome image, the second original monochrome image, the first original color image, and the second original color image. It is preferable to accept the selection.

  According to the first aspect of the present invention, when a character area is extracted from a document image and the character area is composed of characters of two or more colors, the character area is converted into a monochrome image, and the original image is based on the monochrome image. In addition, a first original monochrome image is created, and the first original monochrome image and the first original color image are displayed on the display device. Then, a selection command from the user as to which of the two images is to be printed is received, and the image determined by the selection command is printed on the recording paper. Accordingly, since the first original monochrome image and the first original color image are displayed on the display device and the user's selection is accepted and then printing is performed, an image that is far from what the user imagines can be obtained. It is possible to prevent printing on recording paper, and it is possible to select the image with higher visibility by comparing the original image converted to a monochrome image with the original color original, and as a result , It is possible to prevent the visibility of highlighted characters from being lowered. Furthermore, it is possible to save the trouble of printing again and prevent wasteful consumption of recording paper.

  According to the second aspect of the present invention, the second original monochrome image and the first original created based on the monochrome image obtained by performing the emphasis processing on the character converted into the color different from the original color Since the user can select and print any one of the monochrome image and the first color image, the room for selection is widened, and a more favorite image can be printed.

  According to the invention described in claim 3, since the character converted into a color different from the original color is a hollow character, the visibility of the character whose color has been converted is further improved.

  According to the fourth aspect of the present invention, the second original color image is created by performing color conversion on some characters in the character area in consideration of the remaining amount of toner, and the second original color image is Since the first and second original monochrome images and the first original color image are displayed on the display device and the image selected by the user is printed, only specific toner is biased while reflecting the user's preference. Inefficient situations that can be consumed are avoided.

  FIG. 1 is a schematic side view mainly showing a mechanical configuration of the copying machine when the image forming apparatus according to the present invention is applied to the copying machine. The image forming apparatus includes a main body unit 200, a sheet post-processing unit 300 disposed on the left side of the main body unit 200, an operation unit 400 for a user to input various operation commands and the like, and an upper part of the main body unit 200. The document reading unit 500 is disposed, and the document feeding unit 600 is disposed above the document reading unit 500.

  The operation unit 400 includes a touch panel 401, a start key 402, a numeric keypad 403, and the like. The touch panel 401 displays various operation screens and various operation buttons for the user to input various operation commands. The start key 402 is used for the user to input a print execution command and the like, and the ten key 403 is used for inputting the number of copies to be printed.

  The document feeding unit 600 includes a document placement unit 601, a document discharge unit 602, a paper feed roller 603, a document transport unit 604, and the like, and the document reading unit 500 includes a scanner 501 and the like. The paper feed roller 603 feeds out the original set on the original placement unit 601, and the original transport unit 604 transports the fed originals one by one on the scanner 501. The scanner 501 sequentially reads the conveyed document, and the read document is discharged to the document discharge unit 602.

  The main body 200 includes a plurality of paper feed cassettes 201, a plurality of paper feed rollers 202, a transfer roller 203, an intermediate transfer body roller 204, a photosensitive drum 205, an exposure device 206, and development for each color of yellow, magenta, cyan, and black. Devices 207Y, 207M, 207C, and 207K, a fixing roller 208, a discharge port 209, a discharge tray 210, and the like are provided.

  The photosensitive drum 205 is uniformly charged by a charging device (not shown) while rotating in the direction of the arrow. The exposure device 206 converts the modulation signal generated based on the image data of the original read by the original reading unit 500 into a laser beam and outputs it, and forms an electrostatic latent image on the photosensitive drum 205 for each color. The developing devices 207Y, 207M, 207C, and 207K supply each color developer to the photosensitive drum 205 to form a toner image for each color. Each pixel of the document image data is composed of R (red), G (green), and B (blue) color components, and each color component has a gradation of 0 to 255.

  Each of the developing devices 207Y, 207M, 207C, and 207K includes a toner tank (not shown) that stores toner of each color, and the toner tank has a toner sensor (not shown) for detecting the remaining amount of toner to be stored. It is attached. The toner sensor is composed of, for example, a known piezoelectric element, and is attached to, for example, a side wall of the toner tank. Since the pressure exerted by the toner on the side wall of the toner tank varies depending on the remaining amount of toner, the toner sensor generates a current or voltage signal at a level corresponding to the pressure as a detection signal for the remaining amount of toner, and will be described later. To the unit 10. Thereby, the remaining amount of toner can be detected.

  The intermediate transfer roller 204 transfers the color toner images from the photosensitive drum 205, and forms a color toner image on the intermediate transfer roller 204.

  On the other hand, the paper feed roller 202 pulls out the recording paper from the paper feed cassette 201 in which the recording paper is stored, and feeds the recording paper to the transfer roller 203. The transfer roller 203 transfers the toner image on the intermediate transfer body roller 204 onto the conveyed recording paper, and the fixing roller 208 heats and fixes the transferred toner image on the recording paper. Thereafter, the recording paper is carried into the paper post-processing section 300 from the discharge port 209 of the main body section 200. The recording paper is also discharged to the discharge tray 210 as necessary.

  The paper post-processing unit 300 includes a carry-in port 301, a recording paper transport unit 302, a carry-out port 303, a stack tray 304, and the like. The recording paper transport unit 302 sequentially transports the recording paper carried into the carry-in port 301 from the discharge port 209 and finally ejects the recording paper from the carry-out port 303 to the stack tray 304. The stack tray 304 is configured to move up and down in the direction of the arrow in accordance with the number of recording sheets stacked from the carry-out port 303.

  FIG. 2 is a block diagram showing an electrical configuration of the copying machine shown in FIG. The control unit 10 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The ROM stores a control program for controlling the image forming apparatus, and the CPU executes the control program so that the control unit 10 is changed to the character area extraction unit 11, the color determination unit 12, and the color conversion unit. 13, function as a monochrome image conversion unit 14, a display image creation unit 15, and an exposure control unit 16.

The character area extraction unit 11 extracts a character area, which is an area composed of pixels constituting a character, from the document image read by the document reading unit 500. Here, the character area extraction unit 11 calculates a difference value of luminance between the target pixel and eight neighboring pixels adjacent to the target pixel, and the difference value having a value larger than a predetermined threshold is equal to or greater than a certain number. If there are (for example, four or more), it is determined that the target pixel is a pixel constituting a character, and a character region is extracted. Here, the luminance is expressed by, for example, Expression (1).
Y = 0.299R + 0.587G + 0.114B Formula (1)
However, Y represents luminance, R represents the gradation of the red component, G represents the gradation of the green component, and B represents the gradation of the blue component. By using the luminance represented by the expression (1), it is possible to extract a character region in consideration of human vision. The extracted image of the character area and the image other than the character area are stored in the RAM.

  The color determination unit 12 determines that the color of each pixel in the character area extracted by the character area extraction unit 11 is R (red), G (green), B (blue), C (cyan), M (magenta), Y The color of each character is extracted by determining which color is close to (yellow), K (black), or W (white). Then, the character having the largest number of characters is determined to be the main character, the pixel determined to be white is determined to be the background of the document, and the characters having the other colors are determined to be emphasized characters. Further, as a result of determining the color of each pixel, the color determination unit 12 can extract only a total of two colors of any one color other than white and white (that is, the character region has one color). If it is composed of characters), it is determined that this document is not a color document. Note that when a document other than white is used, white pixels are not determined as background pixels. For example, when a yellow document is used, the document is determined so that yellow pixels are determined as background pixels. A pixel having the same color as the first color is determined as a background pixel.

  The color conversion unit 13 compares the detection value of the remaining amount of toner of each color of C, M, Y, and K detected by the toner sensors 2071C, M, Y, and K with a predetermined value provided for each color, and detects the detected value. Is below the specified value and the toner is a toner used for printing the emphasized character, color conversion is performed on the emphasized character so that the emphasized character is printed with a toner of a color different from the toner. Apply.

  For example, for a manuscript whose main character is black and whose emphasis character is red, if the magenta toner is less than the specified value, but the cyan and yellow toners are larger than the specified value, the emphasis character is cyan and yellow instead of magenta. Is converted into green obtained by mixing the toner, cyan, or yellow.

  The monochrome image conversion unit 14 performs the calculation of Expression (1) for each pixel in the character area, and converts the character area into a monochrome image.

  The display image creating unit 15 creates a first original monochrome image by combining the character area converted into the monochrome image and an image other than the character area. Further, the display image creating unit 15 performs an emphasis process on the emphasized characters in the character area converted into the monochrome image, and synthesizes the obtained image and an image other than the character area to generate the second original monochrome image. Create The display image creation unit 15 performs processing for converting an image other than the character area into a monochrome image before synthesis when creating the first and second original monochrome images.

  Further, the display image creating unit 15 converts the character area composed of R, G, B color components into an image composed of C, M, Y, K color components, and the obtained image and an image other than the character area Are combined to create a first original color image. Further, the display image creation unit 15 synthesizes the image of the character area whose color of the emphasized character is converted by the color conversion unit 13 and the image other than the character area, and creates a second original color image. When the first and second original color images are created, the display image creation unit 15 applies C, M, and Y from R, G, and B color components before synthesis to images other than the character area. , K color components are converted.

  Then, in order to present the obtained first and second original monochrome images and first and second original color images to the user before printing, thumbnail images are created and displayed on the touch panel 401.

  FIG. 3 is a table showing an example of the four types of images created by the display image creation unit 15 for a document composed of black main characters and red emphasis characters. In all the images, the black main character is reproduced in black as it is. In the first original monochrome image, the red emphasized character is converted to gray, and in the second original monochrome image, the red emphasized character is changed. In the first original color image, the red emphasized character is red as it is, and in the second original color image, the red emphasized character is It has been converted to green, cyan and yellow.

  The exposure control unit 16 shown in FIG. 2 selects which image to print between the first and second original monochrome images and the first and second original color images input by the user via the touch panel 401. By accepting the command and driving the image forming unit 20, the selected image is printed on the recording paper. The image forming unit 20 includes the transfer roller 203, the intermediate transfer member roller 204, the photosensitive drum 205, the exposure device 206, and the developing devices 207Y, 207M, 207C for yellow, magenta, cyan, and black shown in FIG. 207K corresponds to the fixing roller 208.

  Next, the process of the image forming apparatus will be described with reference to the flowchart shown in FIG. First, a document image is read by the image reading unit 500 (step S1), and a character region is extracted from the document image by the character region extraction unit 11 (step S2).

  In step S <b> 3, the color determination unit 12 determines which of the colors R, G, B, C, M, Y, K, and W is closest to each character constituting the character area. Details of this processing will be described later. In step S4, the color determination unit 12 determines whether or not the characters in the character area are composed of characters of two or more colors. If the characters are composed of characters of two or more colors (YES in step S4), step S5 is performed. Proceed to On the other hand, if the character area is composed of characters of less than two colors (NO in step S4), the process is terminated because this document is not a color document.

  In step S5, the color conversion unit 13, the monochrome image conversion unit 14, and the display image creation unit 15 create first and second original monochrome images and first and second original color images, and thumbnail images of the respective images. Is displayed on the touch panel 401. Details of this processing will be described later.

  FIG. 5 shows an example of the touch panel 401 on which thumbnail images are displayed. Thumbnail images for the first original monochrome image, the second original monochrome image, the first original color image, and the second original color image are displayed in order from the left.

Below the second thumbnail image from the left is for selecting any one second original monochrome image from among the second original monochrome images obtained by performing various enhancement processes on the emphasized characters. An “enhancement method change” button is displayed. Below the first thumbnail image from the right, any one of the second original color images obtained by performing various color conversions on the emphasized characters is displayed. A “color change” button for selecting the second original color image is displayed. In the present embodiment, various types of emphasis processing include, for example, processing for conversion to a hollow character and a bold character, and each time the “emphasis method change” button is pressed, The second original monochrome image converted into the character is cyclically displayed.
In addition, each time the “color change” button is touched, various color conversions are performed so that highlighted characters printed using toner of a specified value or less are represented by a toner color of a specified value or more. The second original color image is displayed cyclically.

  The exposure control unit 16 accepts a selection command for printing either the first or second original monochrome image or the first or second original color image (step S6). Printing is performed on the recording paper (step S7). In this case, the user issues a selection command by touching one of the four thumbnail images displayed on the touch panel 401 shown in FIG.

  FIG. 6 shows a subroutine of step S3 executed by the color determination unit 12. First, in step S31, | R−G |, | GB |, | B−R |, which are color component difference values, are calculated for each pixel in the first character area, and the difference values of the color components are calculated. Are compared with threshold 1 to threshold 3, respectively.

  In step S32, if there is at least one difference value of each color component that is larger than the threshold value (YES in step S32), the color component having the largest gradation size among the color components of the pixel. And the second largest color component are calculated (step S33), and if the difference value is larger than the threshold 4 (YES in step S34), the pixel is the R, G, B color of the pixel. Among the components, it is determined as a pixel having a color component having the highest gradation (step S35). For example, when the R gradation is the largest among the R, G, and B color components, the pixel is determined to be R (red).

  On the other hand, if NO is determined in step S34, the pixel is determined to be a pixel having a complementary color of the color component having the smallest gradation among the R, G, and B color components (step S36). ). For example, when the R gradation is the smallest among the R, G, and B color components, the pixel is determined as a pixel having a C color that is a complementary color of R.

  If NO in step S32, it is determined in step S37 whether or not the gradation value of each of the R, G, and B color components of the pixel is greater than threshold 5, and if it is greater than threshold 5 (in step S37). YES), the pixel is determined to be white (step S39). On the other hand, if NO is determined in step S37, the pixel is determined to be black (step S38). In step S40, the color of each character is determined from the determination results of steps S35, S36, S38, and S39.

  FIG. 7 shows that the R, G, B color components are 12 pixels of (R, G, B) = (242, 60, 39) to (242, 240, 233) according to the flowchart shown in FIG. It is the table | surface which showed which color is determined, The color components of R, G, B of the illustrated pixel are described in the 1st-3rd column, respectively, The illustrated pixel is shown in the 4th-6th column The values of | R−G |, | GB− |, | B−R | and the determination results for the threshold values 1 to 3 are respectively described in the seventh column. The difference between the color component having the largest tone and the second largest color component and the determination result for the threshold value 4 are shown. The determination result for the threshold value 5 is shown in the eighth column, and the example is shown in the ninth column. The determination result of the color of the selected pixel is shown. Note that 20, 25, 30, 60, and 210 are set for the thresholds 1 to 5, respectively.

  Since the pixel (242, 60, 39) exemplified in the first row is | R−G | = 182 and is larger than the threshold value 1 (= 20), it is determined YES in step S32, and R, G, B Among the color components, the difference between the upper two color components (R and G) is 182 (242-60), which is larger than the threshold value 4 (= 60). Therefore, YES is determined in step S34, and R, G, B The color component R is determined to be R, which is the top color component.

  Further, the pixel (255, 251, 79) illustrated in the fourth row is determined as YES in step S32, and the difference between the upper two color components (R and G) out of the R, G, and B color components is 4. Since it is smaller than the threshold value 4 (= 60), it is determined NO in step S34, and it is determined that Y is the complementary color of the lowest color component (B) among the R, G, B color components.

  In the pixel (242, 240, 233) illustrated in the lowermost stage, the values of | RG |, | GB |, and | BR | are smaller than the threshold values 1 to 3, respectively. Since it is determined as NO and the values of the R, G, and B color components are all greater than the threshold value 5 (= 210), YES is determined in step S37 and W is determined.

  Further, the pixel (100, 88, 95) illustrated in the second row from the bottom is determined as NO in step S32, and the values of the R, G, B color components are all smaller than the threshold value 5 (= 210). Therefore, it is determined as K.

  Next, the subroutine of step S5 will be described using the flowchart of FIG. First, the monochrome image conversion unit 14 converts the character area into a monochrome image (step S51), and various types of enhancement processing are performed on the emphasized characters (step S52). Then, a second original monochrome image is created for each type of enhancement processing (step S54). In step S53, the character area converted into the monochrome image and the non-character area are combined to create a first original monochrome image.

  In step S55, the display image creation unit 15 converts the image data of the character area made up of R, G, B color components into image data made up of C, M, Y, K color components.

  In step S56, the character region converted into the C, M, Y, K color components in step S55 and the region other than the characters (this region is converted into the C, M, Y, K color components in advance). Are synthesized by the display image creation unit 15 to create a first original color image.

  In step S57, the emphasized character in the character area converted into the C, M, Y, and K color components in step S55 is color-converted by the color conversion unit 13 according to the remaining amount of toner of each color (step S57). The color-converted character area and the non-character area (this area has been converted into C, M, Y, and K color components in advance) are synthesized by the display image creation unit 15 to form the second original color image. It is created (step S58). In color originals, red is often used as an emphasized character. For this reason, when color printing is repeatedly performed on a color document including emphasized characters, the consumption of magenta toner becomes significantly larger than the consumption of cyan and yellow toner. Therefore, in this image forming apparatus, this problem is solved by changing the color of the emphasized character in accordance with the toner consumption.

  Next, a process for converting an emphasized character into a hollow character in step S52 shown in FIG. 8 will be described with reference to the flowchart shown in FIG. First, the average value of the luminance of each pixel constituting the main character is calculated (step S60), and the calculated average value is set as the luminance of the emphasized character (step S61). In this state, the emphasized character is represented with substantially the same luminance as the main character, and is difficult to distinguish. Next, for example, the outline of the emphasized character is extracted by a known edge extraction filter, the content of the outline is set to white, which is the background color of the document, and the highlighted character is subjected to a hollowing process (step S62). In this case, since the brightness of the outline of the emphasized character is the average brightness of the main character and the emphasized character is a hollow character, the emphasis degree of the emphasized character can be further increased.

  As described above, according to the image forming apparatus, the first and second original monochrome images and the first and second original color images are displayed on the touch panel 401 and a selection command from the user is received. Since printing on recording paper is executed, it is possible to prevent an image that is far from what the user imagines from being printed on the recording paper, and the visibility of highlighted characters from the four types of images By selecting and printing the image having the highest value, it is possible to prevent the visibility of highlighted characters from being lowered. Further, it is possible to save the trouble of printing again and prevent wasteful consumption of the recording paper.

  In the above embodiment, as the various emphasis processing, the processing for converting into a hollow character and a bold character has been shown, but the present invention is not limited to this, and a memo indicating that the emphasis character is surrounded by a square and is underlined. Processing such as adding between the lines of emphasized characters may be performed.

  Although not shown in the above embodiment, when all color toners are equal to or less than the specified value, the emphasized character may be represented by the color of the toner that is different from the main character and has the largest remaining amount.

FIG. 2 is a schematic side view mainly showing a mechanical configuration of the copying machine when the image forming apparatus according to the present invention is applied to the copying machine. FIG. 2 is a block diagram showing an electrical configuration of the copying machine shown in FIG. 1. A table showing an example of the first and second original monochrome images and the first and second original color images created by the display image creating unit for the original composed of black main characters and red emphasized characters. It is. 5 is a flowchart illustrating processing of the image forming apparatus. An example of a touch panel on which thumbnail images are displayed is shown. It is the flowchart which showed the subroutine of step S3 performed by the color determination part. It is the table | surface which showed an example of which color each pixel is determined by the flowchart shown in FIG. It is a flowchart which shows the subroutine of step S5. It is a flowchart which shows the process in which an emphasized character is converted into a hollow character.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control part 11 Character area extraction part 12 Color determination part 13 Color conversion part 14 Monochrome image conversion part 15 Display image creation part 16 Exposure control part 20 Image formation part 401 Touch panel 500 Original reading part

Claims (4)

An image forming apparatus for forming a color image on a recording paper using a plurality of toners each having a different color,
A document image acquisition means for acquiring a document image;
A character region extracting means for extracting, as a character region, a region composed of pixels constituting a character, based on the luminance of each pixel of the original image;
Color determination means for determining whether or not the character region is composed of characters of two or more colors;
Monochrome conversion means for converting the character area into a monochrome image when the color determination means determines that the character area is composed of characters of two or more colors;
A first original monochrome image that is a monochrome image of the original image is created based on the monochrome image converted by the monochrome conversion means, and the first original monochrome image that has been created and the original image that has not been converted into a monochrome image Image display means for displaying on the display device the first original color image,
Selection accepting means for accepting a selection command to print either the first original monochrome image or the first original color image;
An image forming apparatus comprising: a printing unit that prints an image defined by a selection command received by the selection receiving unit on a recording sheet. The monochrome conversion means performs an emphasis process for notifying the conversion of characters converted to a color different from the original color by converting to a monochrome image,
The image display means creates a second original monochrome image based on the monochrome image enhanced by the monochrome conversion means, and further displays the created second original monochrome image on the display device,
2. The selection accepting unit accepts selection of which of the first original monochrome image, the second original monochrome image, and the first original color image is to be printed. Image forming apparatus.   The image forming apparatus according to claim 2, wherein the enhancement process is a process of converting a character converted into a color different from an original color into a hollow character. Toner remaining amount determining means for determining whether or not the remaining amount of toner of each color is within a specified value;
Of the characters constituting the character region extracted by the character region extraction unit, the color of the character printed by the toner of the color determined to be equal to or less than a predetermined value by the toner remaining amount determination unit is set as the toner remaining amount determination unit. Color conversion means for converting to a color based on toner of a color determined to be larger than the specified value by
The image display means creates a second original color image based on the character region converted by the color conversion means, and further displays the created second original color image on the display device,
The selection accepting unit accepts selection of any one of the first original monochrome image, the second original monochrome image, the first original color image, and the second original color image to be printed. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus.

Images