JP2013105106A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can limit consumption of color developer to a desired consumption or lower with high accuracy.SOLUTION: When monochrome printing or color printing is performed on the basis of image data after gamma correction that is output from a gamma correction processing unit 451 for applying gamma correction on image data on the basis of gamma correction information, a toner counter 47 calculates consumption of color toner during color printing on the basis of image data before the gamma correction by the gamma correction processing unit 451. When the calculated consumption of the color toner is equal to or larger than an upper limit value set in advance, the toner counter 47 limits performing the color printing.

Description

  The present invention relates to an image forming apparatus that executes monochrome printing or color printing based on image data, and more particularly to a technique for limiting consumption of a color developer.

  In an image forming apparatus such as a printer, a copier, a facsimile machine, or a multifunction machine, monochrome printing or color printing is executed based on input image data. In this image forming apparatus, an image is formed with black toner in monochrome printing, and an image is formed with a plurality of color toners in color printing. Here, color printing using a plurality of color toners has a higher printing cost than monochrome printing. Therefore, it is desirable to suppress the execution of color printing from the viewpoint of cost reduction. In this regard, for example, Patent Document 1 discloses a technique for reducing the cost by accumulating and counting the number of printed color originals and limiting the color printing so that the number of printed sheets does not exceed the upper limit number. Yes.

JP 2007-240836 A

Incidentally, the amount of color toner actually consumed by color printing in the image forming apparatus varies greatly depending on the contents of the color document. Therefore, when the color printing is limited by the upper limit number as in the technique according to Patent Document 1, the following problem occurs.
Specifically, when only a color original having a small color image forming area is printed, actual color toner consumption is small. For this reason, when color printing is restricted by the upper limit number, there arises a problem that color printing is unnecessarily restricted. On the other hand, when only a color original having a large color image forming area is printed, actual color toner consumption increases. For this reason, when color printing is restricted by the upper limit number, there is a problem that color toner is consumed more than expected.
Therefore, after the number of dots of CMYK in the image data is counted by the dot counter, the color toner consumption is calculated according to the count value, and the color printing restriction is calculated according to the calculated color toner consumption. It may be possible to determine the presence or absence. Here, the conventional dot counter counts the number of CMYK dots in the image data after performing gradation correction such as gamma correction. However, the image data after gradation correction such as gamma correction changes depending on the content of the gradation correction. Specifically, even if the input image data is the same, the counter value by the dot counter varies depending on the content of correction data such as a gamma correction table used for gradation correction. For example, since the gradation characteristics of an image forming unit change after the image forming unit changes over time or under different usage environments, the image forming apparatus always keeps the print density corresponding to the same image data constant. The content of the gamma correction may be changed depending on the result of calibration performed. Therefore, conventionally, the actual color toner consumption cannot be accurately calculated from the counter value of the dot counter, and the color toner consumption cannot be limited to a desired consumption or less with high accuracy.
Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus capable of limiting the consumption of a color developer to a desired consumption or less with high accuracy. It is in.

In order to achieve the above object, the present invention is configured as an image forming apparatus including the following (1) to (4).
(1) Image data correction means for correcting input image data.
(2) Image formation for executing monochrome printing for forming an image with a black developer based on the image data corrected by the image data correcting unit or color printing for forming an image with a color developer based on the image data means.
(3) Consumption amount calculating means for calculating the consumption amount of the color developer at the time of color printing by the image forming means based on the image data before correction by the image data correcting means.
(4) Print restriction means for restricting execution of the color printing when the consumption amount of the color developer calculated by the consumption amount calculation means is greater than or equal to a preset upper limit value.
According to the present invention, the actual consumption amount of the color developer is accurately calculated based on the image data before correction by the image data correction unit. Specifically, even if the correction content (gamma correction curve or the like) by the image data correction unit changes, if the input image data is the same, the color developer calculated by the consumption calculation unit The amount of consumption is always constant. Therefore, by setting the upper limit value to a desired consumption amount, the color developer consumption in the image forming apparatus can be limited to the desired consumption amount or less with high accuracy.
For example, when the image data correction unit corrects the image data so that the print density by the image forming unit is always constant when the same image data is input, after the correction by the image data correction unit The present invention is suitable because the image data changes appropriately.

Here, when the consumption amount of the color developer calculated by the consumption amount calculation unit is greater than or equal to the upper limit value, the printing restriction unit causes the monochrome printing, the color printing, and the two color developers to be discharged. One or a plurality of two-color printings that are used to form an image are displayed as selection candidates, and the monochrome printing, the color printing, or the two-color printing selected by the operation input according to the display is used as the image data. It is conceivable that the image forming unit is caused to execute the printing. Further, the print restriction unit receives a plurality of image data corresponding to a plurality of documents, and there are a plurality of image data in which the consumption amount of the color developer calculated by the consumption amount calculation unit is equal to or more than the upper limit value. When displaying, each of the image data is displayed, and one or more of the monochrome printing, the color printing, and the two-color printing are displayed as selection candidates, and each image data is displayed by an operation input according to the display. It is also conceivable that the image forming unit is caused to execute printing of each of the image data by the monochrome printing, the color printing, or the two-color printing selected. According to these configurations, the color printing is executed only when the color printing is selected, and when the monochrome printing or the two-color printing is selected, the monochrome printing or the color printing is performed instead of the color printing. Two-color printing is performed. For this reason, when the consumption amount of the color developer is likely to increase, it is possible to select, according to the user's intention, whether to give priority to the execution of the color printing or the restriction on the consumption amount of the color developer.
On the other hand, the printing restriction unit may prohibit the execution of the color printing when the consumption amount of the color developer calculated by the consumption amount calculation unit is equal to or more than the upper limit value. Further, the printing restriction unit performs image formation using the monochrome printing or the two-color developer when the consumption amount of the color developer calculated by the consumption amount calculation unit is equal to or more than the upper limit value. It is conceivable that two-color printing is executed. Thereby, the consumption of the color developer can be limited by automatically prohibiting the execution of the color printing regardless of the intention of the user, or substituting the monochrome printing or the two-color printing.
By the way, the present invention further includes an image reading unit that reads image data from a document, and a document determination unit that automatically determines whether the document read by the image reading unit is a monochrome document or a color document. Therefore, it is preferable that the image forming unit executes the monochrome printing or the color printing in accordance with a determination result by the document determination unit. In other words, according to the present invention, even when the color determination is automatically selected by the document determination unit, it is possible to limit the color printing when the consumption amount of the color developer is excessive. Therefore, the user can use the function of the document determination means without hesitation.
The image data correction means performs gamma correction of the image data based on, for example, gamma correction information (gamma correction curve or the like).

  According to the present invention, the consumption amount of the color developer can be accurately calculated, and the consumption amount of the color developer can be limited to a desired consumption amount or less with high accuracy.

1 is a schematic diagram showing a schematic configuration of a copying machine X according to an embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a control unit 4 in a copying machine X according to an embodiment of the present invention. 6 is a flowchart showing an example of a procedure of image forming processing executed by the copying machine X according to the embodiment of the present invention. 10 is a flowchart showing another example of the procedure of the image forming process executed by the copying machine X according to the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not.
First, a schematic configuration of a copying machine X (an example of an image forming apparatus) according to an embodiment of the present invention will be described with reference to FIG. The present invention is not limited to a copying machine, but can also be applied to an image forming apparatus such as a printer device, a facsimile device, or a multifunction device that executes image formation based on image data.
As shown in FIG. 1, the copying machine X includes an image forming unit 1 (corresponding to an image forming unit), an image reading unit 2 (corresponding to an image reading device), an ADF 3, a control unit 4, and the like. The copying machine X also includes an operation display unit (not shown) for performing various operation inputs and information display.

<Image forming unit 1>
The image forming unit 1 includes two optical scanning devices 10, four image forming units 11, an intermediate transfer belt 12, a secondary transfer device 13, a paper feeding device 14, a fixing device 15, and a paper discharge unit 16. It is configured.
The four image forming units 11 are general electrophotographic image forming units corresponding to four colors of black (K), yellow (Y), cyan (C), and magenta (M) in order from the left in FIG. It is. Each of the image forming units 11 includes a photosensitive drum 111, a charging device 112, a developing device 113, a primary transfer roller 114, a cleaning device 115, and the like.
In the image forming unit 11 configured in this way, the photosensitive drum 111 is uniformly charged to a predetermined potential by the charging device 112. Next, the surface of the photosensitive drum 111 is irradiated with light based on image data by the optical scanning device 10, and an electrostatic latent image is formed on the surface. Then, the electrostatic latent image on the photosensitive drum 111 is developed (visualized) as a toner image by the developing device 113. Subsequently, the toner image on the photosensitive drum 111 is transferred by the primary transfer roller 114 to the intermediate transfer belt 12 traveling in the direction of the arrow shown in the drawing. Note that after the toner image is transferred to the intermediate transfer belt 12, the photosensitive drum 111 is cleaned by the cleaning device 115. The toner image on the intermediate transfer belt 12 is transferred to the recording paper supplied by the paper feeding device 14 by the secondary transfer device 13. Thereafter, the toner image on the recording paper is fused and fixed by the fixing device 15, and the recording paper is discharged to the paper discharge unit 16.

<Image Reading Unit 2>
The image reading unit 2 includes a contact glass 21, a light source unit 23, mirrors 26 and 27, an optical lens 28, a CCD (Charge Coupled Device) 29, and the like, and from an original set on the contact glass 21 or the ADF 3. Read image data.
The contact glass 21 is a transparent document table that is provided on the upper surface of the image reading unit 2 and on which a document P to be scanned is placed.
The reading unit 23 includes an LED light source 24 and a mirror 25, and is configured to be movable in the left-right direction (sub-scanning direction) in FIG. 1 by a motor (not shown). The LED light source 24 includes a large number of white LEDs arranged in the depth direction (main scanning direction) in FIG. 1, and irradiates the reading position 22 on the contact glass 21 with white light for one line. . The mirror 25 reflects the light reflected by the original P at the reading position 22 or the original presser 33 described later toward the mirror 26. The light reflected by the mirror 25 is guided to the optical lens 28 by the mirrors 26 and 27. The optical lens 28 collects incident light and makes it incident on the CCD 29. The CCD 29 inputs an image signal corresponding to the amount of light incident from the optical lens 45 as image data for one line of the original P to the control unit 4.
The color image data reading process performed by the image reading unit 2 configured as described above is not different from the conventional one, and the description thereof is omitted. In the present embodiment, an example in which the CCD 29 is used as an imaging device will be described. However, a contact image sensor (CIS: Contact Image Sensor) having a shorter focal length than the CCD 29 may be used.

<ADF3>
On the other hand, the ADF 3 includes a document setting unit 31, a plurality of transport rollers 32, a document pressing member 33, a paper discharge unit 34, and the like. The ADF 3 drives each of the transport rollers 32 with a motor (not shown), and sequentially sets one or a plurality of documents P set on the document setting unit 31 to set the reading position 22 on the contact glass 21. The paper is passed through and conveyed to the paper discharge unit 34.
The document presser 33 is provided at a position above the reading position 22 on the contact glass 21 at an interval through which the document P can pass. The document presser 33 has a long shape in the left-right direction in FIG. 1, and a white sheet is attached to the lower surface (the surface on the contact glass 21 side). The sheet is used when white reference data is calculated in the image reading unit 2.

<Control unit 4>
Next, the control unit 4 will be described with reference to the block diagram of FIG.
As shown in FIG. 2, the control unit 4 includes a CDS 41, an AGC 42, an ADC 43, a DSP 44, an ASIC 45, an image memory 46, a toner counter 47, a CPU 48, a ROM 49, a RAM 50, and the like. The entire control unit 4 may be composed of an electronic circuit such as an integrated circuit (ASIC).
The CDS 41 is an electric circuit that performs noise removal processing based on a correlated double sampling method on the image data input from the CCD 29. The image data from which noise has been removed by the CDS 41 is input to the AGC 42.
The AGC 42 is a gain control amplifier that amplifies the image data input from the CDS 41 in accordance with a preset amplification factor (gain). The image data amplified by the AGC 42 is input to the ADC 43.
The ADC 43 is an AD converter that converts image data of an analog signal input from the AGC 42 into a digital signal. The image data digitized by the ADC 43 is input to the DSP 44.
The DSP 44 executes a signal conversion process for converting RGB format image data input from the ADC 43 into CMYK format image data. The image data after the signal conversion processing by the DSP 44 is input to the ASIC 45.

The ASIC 45 is a signal processor that performs various types of image processing on the image data input from the DSP 44. Specifically, the ASIC 45 includes a gamma correction processing unit 451 (an example of an image data correction unit) that performs gamma correction, a screen processing unit 452 that performs screen processing, and the like.
The gamma correction processing unit 451 executes gamma correction of image data based on gamma correction information such as a preset gamma correction curve or gamma correction table. The gamma correction is a process for correcting the input / output characteristics of the image data and maintaining the gradation characteristics in the image forming unit 1 constant. By this gamma correction, the image forming unit 1 always forms an image with the same print density if the input image data is the same. The gamma correction information is set in advance according to, for example, each model of the copying machine X or a gamma characteristic unique to the copying machine X. However, the gradation characteristics of the image forming unit 1 of the copying machine X change after the image forming unit 1 changes over time or under different usage environments. Therefore, in the copying machine X, the CPU 48 performs calibration in a timely manner so that the print density by the image forming unit 1 is always kept constant when the same image data is input, and the result of the calibration. The gamma correction information is changed accordingly. As described above, since the gamma correction information is appropriately changed according to the result of the calibration, the image data corrected by the gamma correction processing unit 451 is the gamma even when the same image data is input. It will change as the correction information changes. In this embodiment, the case where the gamma correction is performed on the image data by the gamma correction processing unit 451 is described as an example. However, the present invention is not limited to gamma correction, and various correction processes are performed on the image data. The present invention can also be applied to the applied configuration.
Then, the image data after the gamma correction is input to the screen processing unit 452.

The screen processing unit 452 executes screen processing for realizing gradation expression with halftone dots based on a preset screen pattern or the like. Note that the screen processing unit 452 may execute halftone processing such as dithering and error diffusion. The image data after the screen processing is performed by the screen processing unit 452 is input to the image memory 46.
The image memory 46 is a storage means such as a hard disk or semiconductor memory for accumulating and storing image data read by the copying machine X. In the copying machine X, an image forming process based on the image data stored in the image memory 46 is executed in the image forming unit 1.
Specifically, the image forming unit 1 supplies black toner based on image data read by the image reading unit 2 and subjected to gamma correction by the gamma correction processing unit 451 in the control unit 4. Use monochrome printing to form an image, color printing to form an image using yellow, cyan, and magenta color toners in addition to black, or two-color printing to form an image using only two color toners Is selectively executed.

The toner counter 47 determines the amount of CMYK toner consumed during color printing by the image forming unit 1 based on image data before being input to the gamma correction processing unit 451, that is, image data before gamma correction. calculate. Here, the toner counter 47 used to calculate the color toner consumption amounts of at least CMY colors corresponds to the consumption amount calculation means.
As described above, the toner counter 47 calculates the consumption amount of the color toner based on the image data before the gamma correction processing unit 451 performs the gamma correction. Therefore, as described above, even when the gamma correction information is changed according to the result of the calibration so as to keep the print density corresponding to the same image data constant, the toner counter 47 can accurately consume the toner. Can be calculated. Specifically, the actual color toner consumption can be calculated with higher accuracy than when the color toner consumption is calculated based on the image data after the gamma correction.

Specifically, the toner counter 47 calculates the sum of CMYK gradation values for all pixels included in the image data. The toner counter 47 calculates the amount of toner consumed by each of the image forming units 11 corresponding to each of CMYK according to the total of the gradation values of each of CMYK. For example, the toner counter 47 calculates the toner consumption by multiplying the sum of the gradation values of CMYK by a preset toner consumption constant. The toner consumption constant is a value set for each copying machine X according to the results of experiments and simulations performed in advance. For example, the toner consumption constant corresponding to K is set to 1.5, and the toner consumption constant corresponding to each of CMY is set to 1.35. Of course, the toner consumption constant may be set individually for each CMYK.
Further, for example, the toner consumption constant is individually set for the character part and the other part of the image data, or the toner consumption constant is determined depending on whether the print mode is the normal mode or the photo mode. It is also possible to change. Specifically, the K toner consumption constant is 1.5, the CMY toner consumption constant is 1.35 for the character portion, and the CMYK toner consumption constant is 1.0 for the other portions. It is possible that there is. Further, if the print mode is the normal mode, the CMYK toner consumption constant is 1.0, and if the print mode is the CMYK, the CMYK toner consumption constant is 1.5. Further, in the toner counter 47, table information in which the relationship between the content of gamma correction information (gamma correction table and gamma correction curve type) used in the gamma correction processing unit 451 and the toner consumption constant is determined in advance. Alternatively, the toner consumption constant may be set each time based on the conversion formula as another embodiment.

The ROM 49 stores a predetermined control program and various parameters. The CPU 48 comprehensively controls the copying machine X by executing processing according to a predetermined control program stored in the ROM 49.
Specifically, the CPU 48 controls each component of the copying machine X to read color or monochrome image data from the document P and to form an image based on the image data (FIG. 3). ) Is executed by the copying machine X. The RAM 50 is used as a primary storage area (work area) for various processes executed by the CPU 48.

<Image formation processing>
An example of the procedure of the image forming process executed by the CPU 48 in the copying machine X will be described below with reference to the flowchart of FIG. Here, steps S11, S12... Shown in FIG. 3 indicate processing procedure numbers.

(Steps S11 to S12)
First, in step S11, the CPU 48 waits for a copy process start request (No in S11). For example, when a copy process request operation is performed on an operation display unit (not shown), the CPU 48 determines that a copy process start request has been made (Yes in S11), and shifts the process to step S12.
In step S <b> 12, the CPU 48 executes image reading processing by the image reading unit 2. As a result, the image data read by the CCD 29 is input to the image memory 46 through the CDS 41, the AGC 42, the ADC 43, the DSP 44, and the ASIC 45 in order.
At this time, the toner counter 47 calculates the toner consumption amount of each of CMYK based on the image data input from the DSP 44 to the ASIC 45 as described above, and the calculation result is input to the CPU 48.
Here, the case where the image forming process is executed based on the image data read by the image reading unit 2 in the step S12 will be described. However, in the image forming apparatus such as a printer apparatus or a facsimile apparatus from the outside. The same applies to image forming processing executed based on input image data.

(Steps S13 to S14)
In step S13, the CPU 48 executes ACS determination for automatically determining whether the document read in step S12 is a monochrome document or a color document. Here, the CPU 48 when executing such processing corresponds to the document determination means. The ACS determination method may be a conventionally known technique. For example, it is conceivable that the CPU 48 determines whether the original is a color original or a monochrome original in accordance with a value obtained by counting the number of monochrome pixels or color pixels included in the image data, a ratio thereof, or the like. .
In step S14, the CPU 48 branches the process depending on whether the result of the ACS determination is a color original. Specifically, when the result of the ACS determination is a color document (Yes side in S14), the process proceeds to step S15 to execute color printing. If the result of the ACS determination is not a color document (a monochrome document) (No in S14), the process proceeds to step S141 to execute monochrome printing. However, as will be described later, even when the result of the ACS determination is a color document (Yes side in S14), if the consumption amount of the color toner is equal to or greater than the upper limit (Yes side in S15). ) Execution of color printing is limited.

(Step S141)
In step S141, the CPU 48 causes the image forming unit 1 to execute monochrome printing based on the image data read in step S12. As described above, when it is determined in step S14 that the document is not a color document, the monochrome printing is executed as determined by the ACS determination (S13).

(Step S15)
On the other hand, when the result of the ACS determination is a color document (Yes side of S14), in the subsequent step S15, the CPU 48 presets the total amount of CMY color toner consumption calculated by the toner counter 47. It is determined whether or not the upper limit value is exceeded. The upper limit value is a value set in advance to determine the upper limit amount of color toner consumed in color printing. In the copying machine X, as described later, color printing in which the consumption amount of the color toner exceeds the upper limit is restricted.
Specifically, when it is determined that the sum of the count values is equal to or greater than the upper limit value (Yes side of S15), the process proceeds to step S16, and it is determined that the sum of the count values is not equal to or greater than the upper limit value. Then (No in S15), the process proceeds to step S151.
In another embodiment, the color toner consumption calculated by the toner counter 47 is reset for each copy process. For example, when 10 originals are set in the ADF 3 at a time and copy processing is executed, in step S15, a cumulative value of the color toner consumption calculated for each of the 10 originals is predetermined. It is conceivable to determine whether or not the upper limit value is exceeded. At this time, the CPU 48 may change the upper limit value so that the upper limit value increases as the number of originals to be copied increases and the upper limit value decreases as the number of originals decreases. In addition, the CPU 48 calculates, for example, a cumulative value of the color toner consumption for each day, every month, each user, and each department, and determines whether the cumulative value has reached the upper limit value or more. It is also possible to do.

(Step S151)
In step S151, the CPU 48 causes the image forming unit 1 to perform color printing based on the image data read in step S12. Thus, when it is determined in step S15 that the consumption amount of the color toner is not greater than or equal to the upper limit value, the color toner is not excessively consumed, and therefore the color toner is determined according to the determination result in the ACS determination (S13). Printing is executed.

(Step S16)
On the other hand, if it is determined in step S15 that the consumption amount of the color toner is greater than or equal to the upper limit value, the color toner may be excessively consumed. Therefore, in the subsequent step S16, the CPU 48 executes a print restriction process for restricting color printing based on the image data read in the step S12. Here, the CPU 48 when executing the print restriction process corresponds to a print restriction unit.
Specifically, in the print restriction process, it is considered that color printing based on the image data is prohibited. It is also conceivable that the CPU 48 automatically executes either monochrome printing or two-color printing after prohibiting color printing based on the image data. In this case, the CPU 48 converts the image data from a color image to a monochrome image or a two-color image, and causes the image forming unit 1 to execute a printing process based on the converted image data.
Further, as another example of the print restriction process, the CPU 48 displays a preview screen of the image data on an operation display unit (not shown), and includes the monochrome printing, the color printing, and the two-color printing. Can be displayed as a selection candidate. Then, the CPU 48 causes the image forming unit 1 to execute the monochrome printing, the color printing, or the two-color printing selected by an operation input to the operation display unit (not shown) by the user according to the display. It is possible to make it. Any two of the monochrome printing, the color printing, and the two-color printing may be displayed as selection candidates. In another embodiment, only one of the monochrome printing, the color printing, and the two-color printing is displayed as a selection candidate, that is, the user is allowed to approve execution of printing according to a preset printing type. Is considered.

(Step S17)
Thereafter, in step S17, when the CPU 48 determines that the image reading process for all the originals has been completed for the copy process requested in step S1 (Yes in S17), the series of copy processes is terminated. The process returns to step S11.
On the other hand, when the CPU 48 determines that the image reading process for all the originals has not been completed (No side of S17), the CPU 48 shifts the process to the step S12 and executes the same process for the next original. As a result, a copy process for a plurality of documents is requested, and a plurality of image data corresponding to the plurality of documents is input, and the consumption amount of color toner in the plurality of image data is the upper limit. If there are a plurality of image data that is equal to or greater than the value, the execution of color printing is restricted for each of the plurality of image data (S16).

  As described above, in the copying machine X, the consumption amount of the color toner is calculated by the toner counter 47 based on the image data before the gamma correction processing 451 performs the gamma correction. That is, even if the correction content (gamma correction curve or the like) by the gamma correction processing unit 451 changes, if the input image data is the same, the color toner consumption calculated by the toner counter 47 Is always constant. Therefore, since the actual color toner consumption can be accurately calculated, the color toner consumption is limited to the upper limit or less with high accuracy by limiting the color printing according to the consumption. Can do. When the color toner consumption is less than the upper limit, color printing is executed according to the ACS determination result, so that color printing for a color document with few color images is not unnecessarily restricted. .

<Other examples of image forming processing>
By the way, in the copying machine X, when a plurality of originals are continuously read by the image reading unit 2, the CPU 48 consumes color toner after reading all the image data of the plurality of originals. It is conceivable to individually set the printing type (monochrome printing, color printing, two-color printing, etc.) for each image data having a large amount. The configuration will be described below with reference to FIG.
FIG. 4 is a flowchart for explaining another example of the procedure of the image forming process executed by the copying machine X. Note that the same processing steps as those of the image forming processing shown in FIG.

As shown in FIG. 4, when it is determined in step S14 that the document is not a color document (No side in S14), in the subsequent step S142, the CPU 48 sets monochrome printing as the print type of the image data of the document. .
On the other hand, if it is determined in step S15 that the color toner consumption is not greater than or equal to the upper limit (No in S15), in the subsequent step S152, the CPU 48 performs color printing as the print type of the image data of the document. Set.
On the other hand, if it is determined in step S14 that the document is a color document (Yes in S14), and it is determined in step S15 that the color toner consumption is equal to or greater than the upper limit (Yes in S15), The process proceeds to step S16. In step S161, the CPU 48 suspends the setting of the print type (monochrome printing, color printing, two-color printing, etc.) of the image data of the document.

When the image reading process for all the originals is completed (Yes in S17), the process proceeds to step S18. In step S18, the CPU 48 displays a list (thumbnail display) of each of the image data for which the print type has been suspended in step S161 on the operation display unit (not shown), and as a print type selection candidate for the image data. Color printing, monochrome printing, and two-color printing are displayed. Then, the CPU 48 individually sets the print type of each of the image data according to the operation input to the operation display unit (not shown) by the user according to the display.
Thereafter, in step S19, the CPU 48 performs the printing process for each of the image data in accordance with the print type (color printing, monochrome printing, or two-color printing) set for each of the image data in any of steps S142, S152, or S161. Printing), the image forming unit 1 is executed.
According to such a configuration, the user can print each of the image data by color printing, monochrome printing, or two-color printing while referring to a list of image data displayed on the operation display unit (not shown). Can be set arbitrarily.

1: Image forming unit (corresponding to image forming means)
10: optical scanning device 11: image forming unit 12: intermediate transfer belt 13: secondary transfer device 14: paper feeding device 15: fixing device 16: paper discharge unit 2: image reading unit (corresponding to image reading means)
21: Contact glass 22: Reading position 23: Reading unit 24: LED light sources 25-27: Mirror 28: Optical lens 29: CCD
3: ADF
31: Document setting unit 32: Conveying roller 33: Document pressing unit 34: Paper discharge unit 4: Control unit 41: CDS
42: AGC
43: ADC
44: DSP
45: ASIC
46: Image memory 47: Toner counter 48: CPU
49: ROM
50: RAM
X: Copier (an example of an image forming apparatus)

Claims (8)

Image data correction means for correcting the input image data;
Image forming means for executing monochrome printing for forming an image with a black developer based on the image data after correction by the image data correcting means or color printing for forming an image with a color developer based on the image data;
Consumption calculation means for calculating the amount of color developer consumed during color printing by the image forming means based on the image data before correction by the image data correction means;
Print restriction means for restricting execution of the color printing when the consumption amount of the color developer calculated by the consumption amount calculation means is equal to or greater than a preset upper limit value;
An image forming apparatus comprising:   2. The image forming apparatus according to claim 1, wherein the image data correcting unit corrects the image data so that a print density by the image forming unit is always constant when the same image data is input.   The printing restriction unit uses the monochrome printing, the color printing, and the two-color developer when the consumption amount of the color developer calculated by the consumption amount calculation unit is equal to or greater than the upper limit value. One or more of the two-color prints to be formed are displayed as selection candidates, and the monochrome printing, the color printing, or the two-color printing selected by the operation input according to the display is used to print the image data. The image forming apparatus according to claim 1, wherein the image forming apparatus is executed by the image forming unit.   The print restriction unit receives a plurality of image data corresponding to a plurality of originals, and there are a plurality of image data in which the consumption amount of the color developer calculated by the consumption amount calculation unit is equal to or more than the upper limit value. Each of the image data is displayed, and at least one of the monochrome printing, the color printing, and the two-color printing is displayed as a selection candidate, and is selected for each image data by an operation input according to the display. The image forming apparatus according to claim 3, wherein the image forming unit is configured to cause the image forming unit to print each of the image data by the monochrome printing, the color printing, or the two-color printing performed.   The print restriction unit prohibits execution of the color printing when the consumption amount of the color developer calculated by the consumption amount calculation unit is equal to or more than the upper limit value. An image forming apparatus according to claim 1.   The printing restriction unit is configured to perform image formation using the monochrome printing or two-color developer when the consumption amount of the color developer calculated by the consumption amount calculation unit is equal to or more than the upper limit value. The image forming apparatus according to claim 5, wherein the image forming apparatus executes printing. Image reading means for reading image data from the document, and document determination means for automatically determining whether the document read by the image reading means is a monochrome document or a color document,
The image forming apparatus according to claim 1, wherein the image forming unit performs the monochrome printing or the color printing in accordance with a determination result by the document determination unit.   The image forming apparatus according to claim 1, wherein the image data correction unit performs gamma correction of the image data based on gamma correction information.

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