JP2012030537A - Image forming apparatus, charging rate calculation method, and charging rate calculation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proper rate even when a gray component replacement is performed.SOLUTION: An image forming apparatus includes: an RGB to CMYK conversion unit 2211 that replaces part or all of archromatic pixel in target images into monochroic pixel and generates monochroic pixel images; a transfer toner amount conversion unit 2213 that calculates a monochroic toner usage used for printing the monochroic replacement image and a toner usage used for the other color toners based on associating information regarding the toner used for any color value of the monochroic toners and the other color toners and the toner used per unit region; and a charging calculation unit 23 that calculates a multiplication value where the usage of the monochroic toner is multiplied by a rate per unit quantity of the monochroic toner usage and a multiplication value where the usage of the other colors' toner is multiplied by a rate per unit quantity of the other colors' toner.

Description

  The present invention relates to an electrophotographic image forming apparatus that performs image forming processing using toner, and in particular, an image forming apparatus capable of calculating a charge amount based on a toner usage amount, a charge amount calculation method, and a charge amount It relates to a calculation program.

Some image forming apparatuses that use toner to print images and characters, such as printers, copiers, facsimile machines, and multifunction machines, have a function of suppressing the total amount of toner used while generally retaining color values. is there.
For example, according to an image forming apparatus having a gray component replacement (GCR) processing function, after the CMYK separation, the gray components of the portions where the three colors of the CMY plates are spatially overlapped at a predetermined ratio By substituting with Bk toner, the total amount of toner used can be suppressed while substantially maintaining the chromaticity value (color tone) of the original image.
By the way, as a charging method in such an image forming apparatus, there is a method of determining a charging configuration according to the number of color pixels in image data.
For example, Patent Document 1 discloses a charging method in which color page charging is performed when the number of color pixels exceeds a threshold value, and monochrome page charging is performed when the number of color pixels does not exceed the threshold value.

JP 2002-174929 A

However, according to the above-described charging method, the following problem has occurred when calculating the charging amount of a print image subjected to gray replacement processing.
For example, even if processing is performed with the gray replacement ratio set to the maximum, the gray replacement processing is originally processing that suppresses the amount of color toner used while substantially maintaining the color of the full-color original image. For this reason, although the amount of color toner used is reduced by this process, the amount of reduction is limited. Therefore, when the number of color pixel counts exceeds a prescribed threshold value, the charge amount of the color page is applied.
That is, in this case, even though black toner, which is cheaper than color toner and has a lower image quality, is used preferentially, the color page charge that is higher than the monochrome page charge is still charged at the same amount.
For this reason, there is a strong demerit for the user, and there has been a demand for a new billing method that can present an appropriate fee even when performing gray replacement processing.

  The present invention has been proposed in order to solve the problems of the conventional techniques as described above. That is, the present invention provides an image forming apparatus, a charge amount calculation method, and a charge amount calculation program that calculate a toner usage amount for each toner color when performing gray replacement processing, and calculate a fee based on the calculated toner usage amount. To do.

  In order to achieve the above object, an image forming apparatus of the present invention includes a black replacement unit that generates a black replacement image by replacing part or all of a portion of a target image that can be replaced with black toner with a black pixel; And the amount of black toner used for printing the black replacement image and the amount of the other color toner based on the association information between each color value and the amount of toner used per unit area for the other color toners. A toner usage amount calculating means for calculating a usage amount, a multiplication value obtained by multiplying the usage amount of the black toner by a charge per unit amount of the black toner, and a usage amount of the other color to the usage amount of the other color. And charging means for calculating a multiplication value obtained by multiplying a charge per unit amount of toner as a print charge for the black ink replacement image.

  The charge amount calculation method of the present invention includes a step of generating a black ink image by replacing a part or all of a portion of the target image that can be replaced with black toner with black pixels, and black toner and other color toners. The amount of black toner used for printing the black replacement image and the amount of toner used for the other colors are calculated based on the association information between the arbitrary color value and the toner amount used per unit area. A multiplication value obtained by multiplying the usage amount of the black toner by a charge per unit amount of the black toner, and a charge amount per unit amount of the other color toner to the usage amount of the other color toner And a step of calculating the multiplied value as a printing charge of the black replacement image.

  The charge amount calculation program of the present invention replaces a part or all of a portion of a target image that can be replaced with black toner with a black pixel in a target image, and prints the black replacement image. Based on the association information between the arbitrary color value relating to the generated black replacement means, black toner and other color toners and the amount of toner used per unit area, the black toner used for printing the black replacement image A toner usage amount calculating means for calculating a usage amount and a usage amount of the other color toner, a multiplication value obtained by multiplying the usage amount of the black toner by a charge per unit amount of the black toner, and the other color And a charge unit for calculating a printing fee for the black ink replacement image by multiplying the usage amount of the toner by a charge per unit amount of the other color toners That.

  According to the image forming apparatus, the charge amount calculation method, and the charge amount calculation program of the present invention, the print fee is calculated based on the toner usage amount obtained for each toner color. Can be presented.

1 is a block diagram illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a calculation unit of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a toner usage amount prediction unit of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a weight calculation parameter storage unit of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a block diagram illustrating a configuration of a charging calculation unit of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a block diagram illustrating a configuration of a charging calculation parameter storage unit of the image forming apparatus according to the first embodiment of the present invention. FIG. 6 is a block diagram illustrating a configuration of a toner usage amount prediction unit of an image forming apparatus according to a second embodiment of the present invention. It is a block diagram which shows the structure of the toner usage-amount prediction part of the image forming apparatus which concerns on 3rd embodiment of this invention. It is a block diagram which shows the structure of the charge calculating part of the image forming apparatus which concerns on 3rd embodiment of this invention. It is a block diagram which shows the structure of the toner usage-amount prediction part of the image forming apparatus which concerns on 4th embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First embodiment>
FIG. 1 is a block diagram showing a schematic configuration of an image forming apparatus according to the first embodiment of the present invention.
As shown in FIG. 1, the image forming apparatus 1 performs a receiving unit 3 that receives image data, an image processing unit 4 that rasterizes image data, and image processing such as color conversion based on the rasterized image data. The image forming unit 5 includes an engine unit 6 that performs a printing process, an operation unit 7 that is operated by a user, and a control unit 2 that includes a computer.

The receiving unit 3 receives document or image data (hereinafter referred to as image data) transmitted from a client PC (personal computer) (not shown) via a network such as a LAN (Local Area Network), and performs image processing. This is a network interface to be transferred to the unit 4.
The image processing unit 4 is a rasterizer that performs rasterization processing on image data and decomposes the image data into pixels corresponding to the resolution.
Further, the image processing unit 4 outputs the image subjected to the rasterizing process to the image forming unit 5 and also outputs it to the calculation unit 21 (described later) of the control unit 2.
In this way, by outputting the image data of the target image to the image forming unit 5 that forms an image for printing and the calculation unit 21 that calculates the toner usage amount, the printing process and the toner usage amount calculation process are performed. It can be carried out independently.

The image forming unit 5 is an image processor that converts color values (RGB) of a rasterized image into color values (CMYK) that can be output via the first color conversion table. The image forming unit 5 separates the rasterized image into C, M, Y, and K channels, performs gamma correction processing and screen processing as necessary, and outputs the result to the engine unit 6.
The engine unit 6 forms a toner image on the photosensitive drum based on the image data output from the image forming unit 5, and temporarily transfers the toner image to the transfer belt. Next, the engine unit 6 performs a printing process by transferring the toner image on the transfer belt onto a sheet and fixing the toner image on the sheet with a fixing roller (the photosensitive drum, the transfer belt, and the fixing roller are not shown).

  The operation unit 7 includes a touch panel unit that combines a touch panel and a color LCD (Liquid Crystal Display). The operation unit 7 displays various operation screens and operation keys for inputting an operation command corresponding to a user's touch operation.

The control unit 2 includes a microcomputer such as a CPU, a ROM that stores control programs and data, a RAM that functions as a work memory, and an I / O port. The control unit 2 executes the stored control program and controls each unit constituting the image forming apparatus 1.
Moreover, the control part 2 functions as the calculating part 21 by running a control program. The calculation unit 21 calculates a toner usage amount and calculates a charge amount based on the calculated toner usage amount.
As shown in FIG. 2, the calculation unit 21 includes a toner usage amount prediction unit 22 that predicts a toner usage amount based on the weight calculation parameter stored in the weight calculation parameter storage unit 24, and a charging calculation parameter storage unit 25. A charging calculation unit 23 for calculating a charge based on the stored charging calculation parameter. The weight calculation parameter and the charge calculation parameter will be described later.

FIG. 3 is a block diagram showing a detailed configuration of the toner usage amount prediction unit according to the first embodiment of the present invention.
As shown in FIG. 3, the toner usage amount prediction unit 22 includes an RGB to CMYK conversion unit 2211, a CMYK separation unit 2212, a transfer toner amount conversion unit 2213, a paper toner amount calculation unit 2214, and a temporary ink amount color table selection. A unit 2215 and a black color conversion table storage unit 2216.
The RGB to CMYK conversion unit 2211 (color conversion unit) performs color conversion processing of the target image input from the image processing unit 4. Specifically, the RGB to CMYK conversion unit 2211 selects the color of the target image via one black color conversion table selected from the color table group previously stored in the black color conversion table storage unit 2216 by the temporary ink amount color table selection unit 2215. Perform the conversion process. Here, the black color conversion table is based on a normal color conversion table in which the correspondence between RGB values and CMYK values is configured in a grid pattern at equal intervals or unequal intervals, and among these, for achromatic RGB values The table has a configuration in which black (K) is associated. The black color conversion table storage unit 2216 can store two or more black color conversion tables with different black amount replacement rates determined according to the range of color values.

For example, after CMYK separation, the minimum value among the CMY values at each arbitrary point of the image is obtained, the predetermined value is multiplied by a predetermined ratio, and the amount is replaced with the black amount. Reduce the total amount of toner used. This setting can be changed to an arbitrary range.
By this color conversion processing, for example, after CMYK color separation, there may be a case where all the achromatic parts that are expressed by CMYK mixing can be expressed by only black (K) toner.
Note that if the necessary association information does not exist in the color tables having different ink content ratios, a calculation process using the association information existing on the table is performed. For example, each piece of association information is regarded as a grid point, and the color value can be obtained by interpolation calculation (octahedral interpolation, tetrahedral interpolation, etc.) using some grid points close to the necessary color value.

The CMYK separation unit 2212 (separation processing unit) obtains cyan, magenta, yellow, and black plate images by separating each pixel of the target image into C, M, Y, and K channels.
Thereby, a plate image can be acquired for each color of toner used for printing.

The transfer toner amount conversion unit 2213 calculates the toner weight used for the image to be actually printed based on the weight calculation parameter. The weight calculation parameter is a value indicating the transfer toner weight per unit area corresponding to each color value. The weight calculation parameters are stored in the color value versus weight table 241 of the weight calculation parameter storage unit 24 shown in FIG.
The transfer toner amount conversion unit 2213 obtains the toner weight necessary for printing the target image using the color value versus weight table 241 (see A in FIGS. 3 and 4).

  For example, when determining the weight of black toner, the transfer toner amount conversion unit 2213 sequentially reads the color value assigned to each pixel in the black plate image. The transfer toner amount conversion unit 2213 extracts the transfer toner weight corresponding to each read color value from the color value / weight table 241 and accumulates the extracted weights to obtain the toner use amount of black. Similarly, the color values assigned to the pixels in the cyan, magenta, and yellow plate images are sequentially read, and the transfer toner weights corresponding to the read cyan, magenta, and yellow color values are read from the color value / weight table 241. By extracting and accumulating the extracted weights, the toner usage for all toners is obtained.

The on-paper toner amount calculation unit 2214 performs a process of multiplying the transfer toner weight obtained by the transfer toner amount conversion unit 2213 by the transfer efficiency 242 stored in the weight calculation parameter unit 24 (see B in FIGS. 3 and 4).
As a result, when the target image is printed, the weight (toner usage amount) of each toner of cyan, magenta, yellow, and black that is expected to be used for the printed image on paper can be obtained.

Note that the color value versus weight table 241 can be generated based on the measured value of the toner weight. For example, some known color values based on a predetermined color value interval are selected. Output (draw) a sample image composed of each selected color value (for example, an image having a shape such as a square or a circle whose shape can be easily obtained), and measure the weight of the toner adhering on the transfer belt to obtain the transfer toner weight. .
The weight of the adhered toner can be actually measured by collecting the adhered toner and using a scale.
Further, the paper weight before printing (with no toner attached) can be obtained in advance, the paper weight after printing the sample image can be measured, and the difference between these weights can be obtained as the transfer toner weight. . In this case, it is not necessary to perform a process of multiplying the transfer toner weight of the original image by the transfer efficiency 242 in order to obtain the toner usage amount.

By dividing the measured transfer toner weight by the area of the sample image, the transfer toner weight per unit area can be obtained for each color value in each of cyan, magenta, yellow, and black.
The color value / weight table 241 can be generated by associating the obtained toner weight per unit area with the corresponding color value.
In addition, when adding a color value (for example, intermediate value) other than the measured value to the table configuration, it can be calculated and added by interpolation or the like.
Further, at the time of generating the table, the transfer efficiency in each processing step or the like may be obtained as a correction coefficient for the toner adhesion amount, and correction may be performed using this correction coefficient in a subsequent process.

Incidentally, the image forming apparatus 1 of the present embodiment includes a calibration processing unit 243 as shown in FIG.
Calibration is a correction of input / output characteristics (gamma correction) so that the density (or brightness) at the time of image output when a constant color value is input remains constant even under the influence of environmental changes and changes over time. ). Specifically, the number of print dots is increased or decreased so that a characteristic with a constant input / output characteristic (for example, a prescribed curve shape) is obtained.
In other words, as long as the color value is unchanged, the density corresponding to the color value is also unchanged, and the toner weight corresponding to the color value is maintained at substantially the same value. For this reason, when the calibration functions effectively, the relationship between the color value in the color value versus weight table 241 and the toner weight per unit area is also kept constant.
Therefore, unlike the conventional dot count method, the image forming apparatus 1 of the present embodiment can calculate the toner usage amount at any time without being affected by the increase / decrease of the print dots accompanying the calibration process (density correction). .

Next, billing processing according to the present embodiment will be described with reference to the drawings.
FIG. 5 is a block diagram showing the configuration of the charging calculation unit according to the first embodiment of the present invention. FIG. 6 is a block diagram showing the configuration of the accounting calculation parameter storage unit according to the first embodiment of the present invention.
As shown in FIG. 5, the billing calculation unit 23 includes a billing calculation unit 231, a billing amount display unit 232, and a black amount replacement rate setting unit 233. Further, as shown in FIG. 6, the billing calculation parameter storage unit 25 stores a weight-to-billing table 251 in which charges per unit weight of cyan, magenta, yellow, and black toners are associated with each other.
The charge calculating unit 231 calculates the charge amount of the target image by multiplying the charges per unit toner weight stored in the weight-to-charge table 251 by the toner usage amount of the corresponding color and adding up the charges (FIG. 3, 5 C).
The display unit 232 can display the calculated charge amount on an operation panel or the like. Further, the display unit 232 can display information related to the image quality together with the charge amount. As information about image quality, for example, a thumbnail image after gray replacement processing can be displayed, and the number and ratio of pixels replaced with black by gray replacement processing can be displayed.
If the user accepts the displayed charge amount, the target image that has been color-converted using a color table with a different ink content ratio at that time is printed, while the user accepts the displayed charge amount. If not, the black amount replacement rate setting unit 233 sets a different black amount replacement rate according to the user's operation.
When a new black amount replacement rate is set, the black amount replacement rate is notified to the temporary black amount color table selection unit 2215 (see D in FIG. 5), and the temporary black amount color table selection unit 2215 performs the corresponding black color conversion. A table is selected from the black color table storage unit 2216. The RGB to CMYK conversion unit 2211 performs color conversion processing via the selected black color conversion table (see D in FIG. 3), and the color-converted image is separated into each plate image by the CMYK color separation unit 2212. The charge amount and the like are displayed again. The above-described flow is repeated until the user accepts the displayed charge amount.
In this way, instead of sequentially calculating and displaying the charge amount or the like and asking for the user's judgment, the display unit 232 uses each black color conversion table stored in the black color conversion table storage unit 226. Information on the charge amount and image quality in the case is displayed in a list on the operation panel, the user selects a desired view from the list, and a black color conversion table that realizes the charge amount and image quality related to the selected view is displayed as a temporary ink amount color table The selection unit 2215 may make a selection.

As described above, according to the image forming apparatus 1 according to the present embodiment, the black replacement process for converting the achromatic color pixel into black is performed by color conversion via the black color conversion table. Thus, the amount of use for each toner after the black replacement process performed as described above is obtained.
Further, the toner fee for each color is calculated based on the calculated usage amount for each toner.
For this reason, it is possible to prevent the occurrence of a disadvantage due to the fact that the printing fee for the image subjected to the gray replacement process is not appropriate as in the prior art.
Further, although the number of K pixels is increased by the gray replacement process, the number of C, M, and Y pixels is decreased, so that the toner usage amount and the charge amount can be obtained quickly.

In addition, since the toner usage is not calculated based on the toner weight per unit dot as in the dot count method, the gamma correction processing and the screen processing that perform necessary adjustments by increasing or decreasing the number of printed dots can also be used. The amount of toner used can be calculated.
For this reason, it is possible to quickly determine the amount of toner used regardless of before and after the gamma correction process and the screen process, and it is not necessary to increase the hardware for improving the processing speed unlike the dot count method, and the cost is reduced. Therefore, it is possible to realize the image forming apparatus 1 having excellent properties.
Therefore, according to the image forming apparatus 1 according to the present embodiment, it is possible to calculate the toner usage amount quickly and accurately with a simple configuration.
Further, since the charge amount is calculated according to the toner usage amount thus obtained, an appropriate charge amount can be presented quickly.

<Second embodiment>
Next, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 7 is a block diagram illustrating a configuration of a toner usage amount prediction unit of the image forming apparatus according to the second embodiment of the present invention.
As illustrated in FIG. 7, the toner usage amount prediction unit 22 according to the present embodiment is different from the first embodiment in that a histogram generation unit 2217 is provided.
By holding the histogram, it is possible to easily calculate the amount of toner used, and for some applications (for example, when printing the same image later (including reprinting), gamma correction, etc.) This can be used immediately, for example, when the toner usage is required for the original image after the value fluctuates. Other configurations are the same as those of the first embodiment. For this reason, the same code | symbol is attached | subjected about the same structure and the description is abbreviate | omitted.

In the previous process, the histogram generation unit 2217 according to the present embodiment performs gray replacement processing by the RGB to CMYK conversion unit 2211 performing color conversion via the black color conversion table, and each channel separated by the CMYK color separation unit 2212. Based on the plate image of (C, M, Y, K), a histogram indicating the relationship between the color value and the pixel frequency is generated for each channel.
For example, the histogram can show the correspondence between the color value and the pixel frequency for each plate image by taking the color value on the horizontal axis and the pixel frequency on the vertical axis.
The transfer toner amount conversion unit 2213 can use this histogram and the color value vs. weight table 241 to determine the amount of toner used when printing the image after the gray replacement process.

  The color value versus weight table 241 is an information group in which color values are associated with transfer toner weights per unit area. The histogram is an information group in which color values are associated with the number of pixels. Therefore, the transfer toner amount conversion unit 2213 performs an area correction process for matching the unit area used as a reference for generating the color value / weight table 241 with the area of the unit pixel used for generating the histogram. Even when the transfer toner weight per unit area is obtained by dividing the transfer toner weight of the sample image by the area of the sample image when the color value versus weight table 241 is generated, the pixel resolution (for example, This is because the case of 300 dpi or 600 dpi varies. The area per pixel of images with different pixel resolutions is different. For this reason, the transfer toner amount conversion unit 2213 calculates the transfer toner weight after converting the toner adhesion weight corresponding to one pixel area in accordance with the pixel resolution. In addition, the transfer toner amount conversion unit 2213 calculates the transfer toner weight for each color value by taking the product of the transfer toner weight per unit area corresponding to the same color value and the area corresponding to the pixel frequency. The transfer toner amount conversion unit 2213 can calculate the amount of toner used when printing the image after the gray replacement process, based on the sum of the transfer toner weights corresponding to all the color values.

  In the calculation of the transfer toner weight, when there is no color value corresponding to either the histogram or the color value vs. weight table 241, the corresponding color value or the corresponding color value is obtained by interpolation. The integration is performed.

The on-paper toner amount calculation unit 2214 performs a process of multiplying the toner weight obtained by the transfer toner amount conversion unit 2213 by the transfer efficiency 242 stored in the weight calculation parameter unit 24.
As a result, it is possible to obtain the weight of each toner of cyan (C), magenta (M), yellow (Y), and black (K) that is expected to be used when the target image is printed on paper.

As described above, according to the image forming apparatus 1 according to the present embodiment, the amount of toner used when printing the image after the gray replacement process is represented by a histogram formed by associating the color value with the pixel frequency. It can be obtained smoothly by using it.
Also, by holding the histogram, the toner usage can be recalculated or used immediately if there are other uses.
Further, since the number of pixels of the color value constituting the target image can be reduced, not only the color value vs. weight table but also a histogram can be easily configured, and as a result, toner usage can be calculated quickly. it can.
Further, since the charge amount is calculated according to the toner usage amount thus obtained, an appropriate charge amount can be presented quickly.

<Third embodiment>
Next, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 8 is a block diagram illustrating a configuration of a toner usage amount prediction unit of the image forming apparatus according to the third embodiment of the present invention. FIG. 9 is a block diagram showing the configuration of the accounting unit of the image forming apparatus according to the third embodiment of the present invention.

As illustrated in FIG. 8, the toner usage amount prediction unit 22 according to the present embodiment is different from the above-described embodiments in that a second color conversion table selection unit 2218 and a second color conversion table storage unit 2219 are provided.
Further, as shown in FIG. 9, the billing calculation unit 23 according to the present embodiment is different from the above-described embodiments in that it includes a toner consumption amount setting unit 234.
In other words, the image forming apparatus 1 according to the present embodiment calculates a toner usage amount and a charge amount when a user performs a so-called draft mode in which printing is performed with an output density lighter than a normal output density. is there. Other configurations are the same as those of the above-described embodiments. For this reason, the same code | symbol is attached | subjected about the same structure and the description is abbreviate | omitted.

The second color conversion table selection unit 2218 of the toner usage amount prediction unit 22 according to the present embodiment has a plurality of color conversion tables (hereinafter, second color conversion tables) having different density setting rates stored in the second color conversion table storage unit 2219. A second color conversion table is selected from the color conversion table.
Therefore, the user can change the set color conversion table to an arbitrary second color conversion table, and can change the second color conversion table once selected to another second color conversion table. Is also possible.
The draft color table of this embodiment is obtained by replacing the output color value in the above-described black color conversion table with a color value having a lighter density. For this reason, when color conversion is performed via the second color conversion table of the present embodiment, an image in which both the gray replacement process and the light color reduction process in the draft mode are performed is formed.
That is, according to the present embodiment, not only the effects shown in the first embodiment and the second embodiment, but also the density of the output image can be suppressed, so that the toner usage amount and the charge amount can be further reduced. Can do.

The second color conversion table selection unit 2218 performs an operation of selecting a predetermined second color conversion draft color table in response to a request from a toner consumption setting unit 234 described later.
Specifically, as shown in FIG. 9, when the user does not accept the charge amount calculated for the target image by the charge calculation unit 231, the toner consumption amount setting unit 234 displays the currently set color conversion table (black color conversion). A density setting rate of an output density lighter than that (including a table and a second color conversion table) is set, and this is notified to the second color conversion table selection unit 2218 (see D in FIG. 9).
Receiving the notification of the density setting rate, the second color conversion table selection unit 2218 takes out the second color conversion table corresponding to the density setting rate from the second color conversion table storage unit 2219 and replaces it with the current color conversion table ( (See D in FIG. 8).
Then, the toner usage amount prediction unit 22 calculates the toner usage amount based on the color value obtained by the color conversion process via the new second color conversion table after the change.
When the user approves the charge amount at the time of printing the target image calculated by the charge calculation unit 231, the charge amount is output, for example, stored in a storage medium, recorded on a recording medium, or by a display unit Is displayed.

As described above, according to the image forming apparatus 1 of the present embodiment, the charge amount is obtained based on the amount of toner used during color printing in the draft mode with gray replacement processing.
Therefore, even when an image subjected to the gray replacement process is further printed in the draft mode, the same operation and effect as those of the above-described embodiments can be obtained, and the toner usage amount and the charge amount can be obtained more quickly.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 10 is a block diagram illustrating a toner usage amount prediction unit of the image forming apparatus according to the fourth embodiment of the present invention.

As illustrated in FIG. 10, the toner usage amount prediction unit 22 according to the present embodiment is different from the third embodiment in that a draft mode processing unit 2220 is provided.
In other words, the image forming apparatus 1 according to the present embodiment is the same as the third embodiment in that the amount of toner used and the amount of charge at the time of draft mode printing are obtained, but the process associated with lightening in the draft mode is color-converted. It differs in that it is performed in the previous process. Further, the second embodiment is different from the third embodiment in that color conversion processing is performed via the black color conversion table without using the second color conversion table. Other configurations are the same as those of the third embodiment. For this reason, the same code | symbol is attached | subjected about the same structure and the description is abbreviate | omitted.

The draft mode processing unit 2220 can obtain an output color value (CMYK) having a lighter density than the output color value of the target image output from the image processing unit 4 via the black color conversion table. RGB).
Specifically, the arithmetic processing of the following expression (1) is performed on the RGB values of each pixel constituting the target image.
(R ′, g ′, b ′) = (255,255,255) − {(255,255,255) −ρ (r, g, b)}
(1)
(However, (r, g, b) is the RGB value before processing, (r ′, g ′, b ′) is the RGB value after processing, the number of gradations is 256 gradations, and the set density ratio ρ (0 ≦ ρ ≦ 1))

The draft mode processing unit 2220 outputs the color values (r ′, g ′, b ′) acquired by the processing to the RGB to CMYK conversion unit 2211. The RGB to CMYK conversion unit 2211 performs color conversion processing using the black color conversion table. As a result, the toner usage amount required when the image subjected to the gray replacement process is printed in the draft mode is calculated.
In addition, the charging calculation unit 23 calculates a charging amount based on the calculated toner usage amount.

As in the third embodiment, when the user does not accept the charge amount calculated by the charge calculation unit 231, the toner consumption amount setting unit 234 sets the density setting rate of the output lighter than the currently set density setting rate. This is set, and this is notified to the draft mode processing unit 2220 (see D in FIG. 9).
Receiving the notification of the density setting rate, the draft mode processing unit 2220 performs image processing based on the above-described formula (1) using the draft mode rate (see D in FIG. 10).
Then, the toner usage amount prediction unit 22 calculates the toner usage amount based on each color value of the processed image.

As described above, according to the image forming apparatus 1 according to the present embodiment, the toner usage amount and the charging amount at the time of the draft mode printing accompanied with the gray replacement process are obtained.
Specifically, without using the second color conversion table, the pixels before the color conversion are drafted, and then the toner at the time of the draft color printing of the image after the color conversion through the black color conversion table The usage amount and the billing amount are calculated.
For this reason, the same operations and effects as those in the fourth embodiment can be achieved during draft mode printing.

Further, in the present embodiment, the lightening process in the draft mode printing is performed in the previous process of the color conversion process, and the toner usage amount and the charge amount are calculated based on the image acquired through the color conversion process based on the normal color conversion table. I am trying to calculate.
For this reason, the number of channels to be processed (three channels of R, G, and B) is smaller than the number of channels after the color conversion processing (four channels of C, M, Y, and K). The processing load can be reduced, and as a result, the amount of toner used can be quickly obtained.

Further, compared with the case where draft mode printing is performed by selecting from a plurality of second color conversion tables, the density setting rate can be set more finely and there is no limit on the capacity to be held, so the degree of freedom is large.
Further, when draft mode printing is performed, the influence upon conversion to an ink type or output format (CMYK value) dependent on the apparatus is less than that in the case of performing draft mode processing after color conversion.
For this reason, according to the present embodiment, it is possible to perform the draft mode printing without affecting the output characteristics, and it is possible to accurately and quickly calculate the toner usage amount and the charging amount at that time.

The image forming apparatus 1 according to the present invention has been described with reference to the preferred embodiments. However, the image forming apparatus 1 according to the present invention is not limited to the above-described embodiments, and may be variously within the scope of the present invention. Needless to say, it is possible to implement this change.
For example, in each embodiment, the toner usage amount is obtained using the color value vs. weight table 241. However, the toner usage amount is calculated based on a mathematical expression or a simulator corresponding to the association between the color value and the toner weight. You can also
Moreover, it is good also as a structure which combined 2nd embodiment which has a histogram production | generation part in structure, and 3rd embodiment and 4th embodiment which concern on draft mode printing.
In each of the above embodiments, the printer has been described as an example. However, the present invention can be widely applied to image forming apparatuses such as a copying machine or a multifunction machine having a copying function and a printing function.

  The present invention can be suitably used in an electrophotographic image forming apparatus that performs printing using toner.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 21 Calculation part 22 Toner usage-amount prediction part 23 Charge calculation part 231 Charge calculation part 232 Toner consumption setting part 24 Weight calculation parameter storage part 241 Color value vs. weight table 25 Charge calculation parameter storage part 251 Weight vs. charge table

Claims (7)

A black ink replacement unit that generates a black ink replacement image by replacing some or all of the achromatic pixels in the target image with black ink pixels;
Based on the association information between each color value relating to black toner and other color toners and the amount of toner used per unit area, the amount of black toner used for printing the black replacement image and the other color A toner usage calculation unit for calculating the toner usage;
A multiplication value obtained by multiplying the usage amount of the black toner by a charge per unit amount of the black toner, and a multiplication value obtained by multiplying the usage amount of the other color toner by a charge per unit amount of the other color toner. And an accounting unit that calculates a printing fee for the black ink replacement image. A black color conversion table storage unit that stores a black color conversion table in which part or all of the output color values associated with the achromatic color in the color conversion table in which the input color value and the output color value are associated with each other are replaced with black;
A color conversion unit that performs color conversion on the target image via the black color conversion table;
A color separation processing unit for forming a black plate image and the other color plate image based on the color-converted image;
Based on the black plate image and the plate image of the other color, a histogram of black that associates a color value with the number of pixels and a histogram generation unit that generates a histogram of the other color, and
The toner usage amount calculation unit
The usage amount of the black toner is calculated based on the black histogram and the association information, and the usage amount of the other color toner is calculated based on the other color histogram and the correlation information. Image forming apparatus. A black ink replacement rate setting unit that sets a black amount replacement rate determined according to the color value range is provided.
Two or more black color conversion tables in which the black color conversion table storage unit replaces some or all of the output color values associated with the achromatic color of the color conversion table with black according to two or more different black amount replacement rates. Store
The image forming apparatus according to claim 2, wherein the color conversion unit performs color conversion on the target image through a single black color conversion table selected based on the set black amount replacement rate. A draft color table storage unit that stores one or more draft color tables in which an output color value corresponding to an input color value is a value less than the density of the output color value in the black color conversion table;
The image forming apparatus according to claim 2, wherein the color conversion unit performs color conversion on the target image through a single draft color table selected according to a predetermined selection operation.   The draft color processing means for changing the color value of the target image so that the output color value corresponding to the input color value is less than the density of the output color value in the black color conversion table. The image forming apparatus according to claim 1. Replacing a part or all of the achromatic pixels in the target image with black pixels to generate a black ink replacement image;
Based on the association information between each color value relating to black toner and other color toners and the amount of toner used per unit area, the amount of black toner used for printing the black replacement image and the other color Calculating the amount of toner used;
A multiplication value obtained by multiplying the usage amount of the black toner by a charge per unit amount of the black toner, and a multiplication value obtained by multiplying the usage amount of the other color toner by a charge per unit amount of the other color toner. And calculating as a printing fee for the black ink replacement image. A computer that prints images
A black ink replacement unit that generates a black ink replacement image by replacing some or all of the achromatic pixels in the target image with black ink pixels;
Based on the association information between each color value relating to black toner and other color toners and the amount of toner used per unit area, the amount of black toner used for printing the black replacement image and the other color A toner usage amount calculation unit for calculating a toner usage amount, a multiplication value obtained by multiplying the usage amount of the black toner by a charge per unit amount of the black toner, and a usage amount of the other color toner. A charge amount calculation program for causing a multiplication value obtained by multiplying a charge per unit amount of color toner as a charge portion for calculating a print fee for the black ink replacement image.

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