JP2013110465A - Image forming apparatus, image processing method, program, and recording medium - Google Patents

Abstract

To reduce the amount of color material used for forming a full-color image so as to maintain the image quality as a full-color image.
A reduction target amount is calculated from the total amount of toner used at the time of normal full color printing and existing toner save (low cost printing) by non-full color printing such as monochrome printing and two-color printing (S101), and K reduction method The reduction amount is reflected on the image data used for full-color toner save printing by the method selected by the user (S102) among the color equalization reduction methods (S103 to S106). Both reduction methods use a change in the gamma table.
[Selection] Figure 11

Description

  The present invention relates to an image forming apparatus such as a printer or a multi-function peripheral that forms an image on recording paper using output image data generated based on print data, and a color obtained by reducing a predetermined amount from an appropriate amount in accordance with an instruction of a saving condition. The present invention relates to an image forming apparatus capable of forming an image with a material usage amount, an image processing method in the image forming apparatus, a program for executing the image processing, and a recording medium on which the program is recorded.

2. Description of the Related Art Conventionally, image forming apparatuses such as printers and multifunction peripherals that form images on recording paper based on print data may be used by a method of charging a usage fee for print output.
At this time, as for the charge amount of the usage fee, the charge amount is mainly calculated from the number of printed sheets and a preset unit price per sheet, and the unit price is different for monochrome printing and full color printing. .
In such a usage fee charging method, if any color information is included in the document to be printed, it is counted as a full color print, so the user saves a fee in such a color document. Choose monochrome printing that reduces the amount of color material used, or choose a two-color printing (printing with only two colors) that costs the same as monochrome printing.

Further, in the image forming apparatus that operates the above-described charging method, a function for showing a user a printing method that can be used in accordance with the charging amount has been proposed. 2002-268861 gazette).
Japanese Patent Application Laid-Open No. 2004-151561 describes means for allowing a user to input a desired amount of money, displaying a printing method that can be selected by the user within the desired amount of money, and allowing the user to select a desired printing method. Here, it is shown that it is possible to instruct whether or not to select a toner saving that reduces toner consumption as a selectable method.

By the way, in monochrome printing and two-color printing, which reduce the printing fee by reducing the amount of color material used, the printed matter has only one or two colors, so it is difficult to understand the boundary between regions that can be distinguished by full-color printing. There arises a problem that the output image quality deteriorates.
FIG. 12 is a diagram showing images of full-color printing (A) and two-color printing (B) for reducing the amount of color material used in the prior art.
Each image shown in the figure is printed based on print data for drawing the same pie chart. In the image of full color printing (A), the boundary between the sectors of the pie chart composed of the sectors S1, S2, S3,..., S11 can be recognized by the difference in color. On the other hand, each image of the two-color printing (B) has a sector S11 (originally dark yellow) and a sector S1 (originally dark blue), or a sector S3 (originally light yellow) and a sector S4 (originally light yellow). The boundary between the sky blue) becomes the same color, and the boundary is not understood.

As shown in the example of FIG. 12, if the boundary between the sectors of the pie chart is not known, information as a pie chart is lost, resulting in a defective image. That is, there arises a problem that the image quality as a full-color image is impaired.
Note that the toner-saving described in the above-mentioned Patent Document 1 only shows that the toner consumption can be selected to be reduced, and there is no place to show the condition considering the image quality of the full-color image.

  An object of the present invention is to reduce the amount of color material used for forming a full-color image so as to maintain the image quality as a full-color image in an image forming apparatus that forms a full-color image on recording paper based on print data. is there.

  In the present invention, when an image is formed based on print data, a normal operation for forming a full-color image with an appropriate amount of color material used is performed, and the color in the normal operation according to a saving condition added to the print data. An image forming apparatus that performs a color material saving operation for forming an image with a color material usage amount obtained by reducing a predetermined amount from the material usage amount, and a total color material usage amount in print data to be processed according to the instructed saving conditions The reduction amount calculated by the reduction amount calculation means is reflected in the total amount of color material used for each pixel on the condition that the reduction amount calculation means for calculating the reduction amount of each pixel and the full color image are maintained. And an image processing unit that generates image output data based on the print data to be processed.

  According to the present invention, when a full color image is formed based on print data, it is possible to reduce the amount of color material used while maintaining the image quality as a full color image.

1 is a diagram illustrating an outline of a configuration of a printer according to an embodiment of the present invention. FIG. 6 is a diagram illustrating toner usage during normal printing in the printer according to the embodiment of the present invention. FIG. 6 is a diagram illustrating toner usage during two-color printing in the printer according to the embodiment of the present invention. FIG. 5 is a diagram illustrating toner usage during full-color toner save printing in the printer according to the embodiment of the present invention. FIG. 5 is a diagram for explaining a gamma table used for processing of an equal reduction method during full-color toner save printing (see FIG. 4). FIG. 6 is a diagram illustrating toner usage during normal printing in the printer according to the embodiment of the present invention. FIG. 6 is a diagram illustrating toner usage during two-color printing in the printer according to the embodiment of the present invention. FIG. 5 is a diagram illustrating toner usage during full-color toner save printing in the printer according to the embodiment of the present invention. FIG. 10 is a diagram illustrating transition of an operation screen for instructing full-color toner save printing from an operation panel. FIG. 10 is a diagram illustrating a combo box on an operation screen that instructs toner save printing created by a printer driver. 6 is a flowchart of output image data processing during printing in full-color toner save printing in the printer according to the embodiment of the present invention. It is a figure which shows each image of two-color printing (B) which reduces full color printing (A) and a coloring material usage-amount in a prior art.

Embodiments of the present invention will be described with reference to the accompanying drawings.
Hereinafter, the image forming apparatus of the present invention will be described by taking as an example a printer that is an embodiment thereof, that is, a printer that forms a full-color image with output image data (pixel signals) drawn based on print data.
When this output image data is processed, the output image data reflecting the reduction amount of the total color material use amount determined for each pixel corresponding to the saving condition added to the original print data is processed. Generate.

The output image data reflecting the reduction amount of the total color material use amount will be described in detail later, but the data value after the reduction of each color component is obtained for each pixel on the condition that the full color image is maintained, An image formed using this output image data suppresses deterioration in image quality as a full-color image that occurs in monochrome printing or two-color printing, which is used in place of full-color printing in the prior art to save color materials. And keep the image quality.
In the following description, a printer is exemplified as an embodiment of the present invention. However, output image data that reflects the reduction amount of the total amount of color material used determined for each pixel corresponding to the saving condition is generated and generated. Any device that forms an image using output image data is not limited to a printer.

[Printer configuration]
FIG. 1 is a diagram showing an outline of the configuration of a printer according to an embodiment of the present invention.
The printer 20 includes a controller 10 that controls the entire printer 20, a printer engine 23 that forms an image on recording paper based on rendered output image data, and an operation unit such as a display unit and input keys. An operation panel 24 that provides a function as an interface is provided.

  The controller 10 includes a CPU (Central Processing Unit) 11 for executing instructions of the software program, and a ROM (Read Only Memory) 12 for storing a control program and control data used by the CPU 11 for operating the controller. RAM (Random Access) used as a page (frame) memory for temporarily storing rendered output image data generated by the control program or a work memory for storing data necessary for the operation of the software program The configuration element includes a memory (RAM) 13 and an NVRAM (Non Volatile RAM) 14 that is a non-volatile memory for storing setting data such as processing conditions depending on the device, management information of the apparatus (printer 20), and the like. That is, the main part of the controller 10 is configured by a computer including the CPU 11, the ROM 12, the RAM 13, and the NVRAM 14.

Further, the controller 10 includes an engine I / F (interface) 16 for exchanging data with the printer engine 23, an operation panel I / F 17 for exchanging data with the operation panel 24, a network A network I / F 15 for exchanging data with a PC (hereinafter referred to as a “host PC”) 40 as a host device equipped with a means for creating print data such as a printer driver connected above is configured. Have as an element.
Note that the above-described elements constituting the controller 10 are connected via an internal bus 19.

  The host PC 40 uses a predetermined printer driver to convert a document, web page, or the like created or processed by an application into print data describing drawing conditions including various drawing commands. And request printout. The print data is expressed by data described in PDL such as PostScript (registered trademark).

The controller 10 performs drawing processing including various conversion processes based on print data received from the host PC 40, generates output image data used for printing, and causes the printer engine 23 to perform printing (image output). The procedure is managed, the operation is controlled according to the operation procedure, and data processing such as image data is executed.
At this time, the CPU 11 of the controller 10 reads the control and processing programs stored in the storage device such as the ROM 12 and the NVRAM 14 and setting information relating to the operating conditions, expands them in the memory area of the RAM 13, and controls and processes the RAM 13. By using it as a work area for execution, the print data received from the host PC 40 and the control and processing operating conditions instructed from the operation panel 24 (including instructions for executing the color material saving execution and saving conditions described later) ), Intermediate data format image data, raster format pixel data, and output image data used for full-color printing by the printer engine 23 are generated.

[Image output processing according to instructions to save color materials]
Next, an operation performed by the printer 20 in response to an instruction when printing is performed while reducing the amount of color material used by the user will be described. In the following description, the printer 20 is a printer that forms an image by an electrophotographic method, and an operation using toner as a color material is taken as an example, and the operation of performing printing while reducing the amount of toner used is referred to as “toner”. This is called "save" action.
The color material usage amount is instructed by a method of accepting an operation for instructing toner save performed by the user from the operation panel 24, or a function for instructing this to a printer driver installed in the host PC 40. This is based on a method of describing data for instructing toner save in a part of print data.

The instruction for saving in the toner save indicates whether or not to reduce the color material usage amount, and when further saving, the saving condition related to the execution of the saving is instructed.
In other words, the conditions for saving are as follows:
Saving condition 1: Target amount of saving of color material usage Saving condition 2: The application method of saving to full color printing is a condition.
Next, each of the saving conditions 1 and 2 will be described.

<Target amount of color material usage reduction>
The saving condition 1 is a condition that indicates how much or how much color material usage is to be saved and a target amount of saving.
Since the user is instructed to reduce the amount of color material used, the user can specify the conditions that are easy to understand for the user and that are expressed in the printing state such as “light” or “slightly thin” depending on the result of saving. (Refer to FIGS. 9 and 10 to be described later).
Further, in this printer 20, in order to reduce the amount of color material used, the same amount of use can be saved by non-full-color printing such as monochrome printing and two-color printing, which has been adopted instead of full-color printing. Since it is realized by an image, it is possible to instruct a target amount of reduction in the amount of color material used that is determined on the assumption of these conditions (see FIGS. 9 and 10 to be described later).

Therefore, in order to perform full-color printing that reflects the target amount of reduction in the amount of color material used that is indicated by the user with expressions such as “thin” and “slightly thin”, and expressions such as monochrome and two-color printing. Therefore, it is necessary to obtain the color material usage amount to be reduced in pixel units. Further, the total amount of color material used for each pixel is grasped based on the obtained result.
Note that the process of calculating the total color material usage amount in units of pixels determined according to the instructed target amount of reduction of the color material usage amount will be further described in an embodiment described later.

<How to apply savings to full-color printing>
The color material usage to be reduced is determined according to the color material usage target of the saving condition 1, and the output image data to be used for full color printing based on the total color material usage per pixel grasped according to this reduction amount. Is generated.
Here, the output image data generated by reflecting the reduction amount is on condition that a full color image is maintained, and full color printing is performed under these restrictions.

When full-color printing is performed under these restrictions, the image quality of the printing result varies depending on how the output image data is generated by reducing each color component.
Thus, two examples will be described in which the reduction amount is reflected and a full-color image can be maintained and can be employed as means for generating output image data by different methods.
One of them is based on a method of achieving the target reduction amount by equalizing the reduction rate of each color component (hereinafter also referred to as “equal reduction method”).
The other is based on a method of reducing only the black (K) component to achieve a target reduction amount (hereinafter also referred to as “K reduction method”).
The above two methods will be described more specifically in the following first and second embodiments.

<Embodiment 1>
Here, the above-mentioned saving condition 1 is set as a target amount of reduction in use amount of the color material (toner) equivalent to the two-color printing, and the saving condition 2 is set as the reduction amount of each color material (toner) by the uniform reduction method. A toner save operation performed by the printer 20 that generates data will be described.
FIG. 2 is a diagram illustrating the amount of toner used during normal printing in the printer 20 according to the embodiment of the present invention.
FIG. 2A shows a result of normal printing in which toner save is not instructed, that is, when printing is performed using output image data obtained through appropriate processing without changing the print data to be processed. The result of printing is shown.

FIG. 2B is a graph showing the toner usage of each color component (C: cyan, M: magenta, Y: yellow, K: black) of a certain pixel in the output image of FIG. 2A. The total toner usage amount of the pixels shown in the graph of FIG. 2B is calculated from the toner usage amount of each color component, and a total “190” is obtained.
The output image of FIG. 2A is output by full-color printing, as can be seen from the graph of FIG. 2B. Therefore, when the print result is charged, it is charged as full-color printing.

FIG. 3 is a diagram illustrating the amount of toner used during two-color printing in the printer 20 according to the embodiment of the present invention.
FIG. 3A shows output image data used for two-color printing of M and K based on the printing result when toner saving of two-color printing is instructed, that is, the same print data as in the full-color printing of FIG. 2A. The printing result when printing is performed using the output image data generated and obtained is shown.

FIG. 3B is a graph showing the amount of toner used for each of the M and K color components in a certain pixel in the output image of two-color printing (FIG. 3A). 3B represents the toner usage of the same pixel as the pixel shown in FIG. 2B. The total toner use amount of the pixels shown in the graph of FIG. 3B is calculated from the toner use amounts of the respective color components of M and K, and a total “140” is obtained, and the toner use amount is reduced compared to “190” of FIG. 2B. doing.
The output image in FIG. 3A is an example of a case where charging less expensive than full-color printing may be set when charging the printing result because the amount of toner used is reduced. However, the image quality is lower than the result of the full-color printing shown in FIG. 2A, and the boundary between colors is not known depending on the color (see the description with reference to FIG. 12 in the [Background Art] above).

Therefore, this printer 20 aims to reduce the amount of toner equivalent to two-color printing, and reduces toner for each color by the uniform reduction method to reduce the total amount of toner used (hereinafter referred to as “full-color toner save”). Can be performed).
FIG. 4 is a diagram illustrating the amount of toner used during full-color toner save printing in the printer 20 according to the embodiment of the present invention.
FIG. 4A shows the amount of toner used for each color of C, M, Y, and K in a uniform reduction method based on the printing result when full color toner save is instructed, that is, the same print data as in the full color printing of FIG. 2A. The output image data is generated by reducing the same amount as the two-color printing, and the print result when printing is performed using the obtained output image data is shown.

FIG. 4B is a graph showing the amount of toner used for each of the C, M, Y, and K color components in a pixel in the output image of full-color toner save printing (FIG. 4A). 4B represents the toner usage amount of the same pixel as the pixels shown in FIGS. 2B and 3B.
In the graph of FIG. 4B, as indicated by arrows in the figure, the amount of toner used for each color of C, M, Y, and K is reduced, and the total amount of toner used for this pixel is C, M, The total amount of toner used for each of the Y and K color components is “140”, which is equivalent to the two-color printing shown in FIG. 3B.

According to full-color toner save printing (FIG. 4A), the entire image becomes thinner by the amount of toner used for each of the C, M, Y, and K color components reduced, but a full-color image can be maintained. In this two-color printing, it is possible to suppress the disadvantage that the color boundary is not known depending on the color (see the description with reference to FIG. 12 in the above [Background Art]).
In addition, since the amount of toner used is reduced, it is possible to operate a charging system that sets a lower charge than normal full-color printing without applying toner save when charging the printing result. .

“Equal reduction method”
Here, the above-described equal reduction method employed when generating output image data with reduced toner usage will be described in more detail.
In the full-color toner save printing performed by the printer 20, the amount of toner to be used is as described with reference to FIGS. Depends on the print data, calculate the total amount of toner used during normal full-color printing and the total amount of toner used during two-color printing, and reduce the difference between the calculated total amounts of toner used to reduce the total amount of toner used in full-color toner save printing Get as a quantity. Further, the amount of toner used for each color component that achieves the target reduction amount thus obtained is determined in units of pixels.

One of the methods for determining the reduction amount of each color component with respect to the toner usage amount that achieves the target reduction amount of the total toner usage amount is the “uniform reduction method”.
The uniform reduction method is a method in which the reduction rate for each color component is made constant and the target reduction amount of the total amount of toner used is achieved.
In order to perform printing with the amount of toner used for each color determined by the uniform reduction method, it is necessary to generate image data used for this print output. The processing for generating the output image data is performed by the image processing means included in the controller 10.

Specifically, the controller 10 first obtains the total toner use amount in full-color toner save printing from the target reduction amount of the total toner use amount and the total toner use amount when the toner save is not applied.
Further, output image data in which the toner usage amount of each color component is determined at a constant reduction rate so as to be the total toner usage amount obtained by the above processing is generated. At this time, the reason why the reduction rate is constant for each color is to maintain the color balance in the image obtained by the toner save printing.
By performing the above processing, intended full color toner save printing can be performed.

Generation of output image data that determines the amount of toner used for each color component at a fixed reduction rate. For example, the gamma table data used for gamma correction processing that corrects and outputs input data is changed according to the reduction rate of toner usage. This can be done. Note that the reduction rate of the toner usage amount is targeted when the reduction amount of the two-color printing taken in the above example is targeted.
This is a numerical value obtained as the total amount of toner used during two-color printing / the total amount of toner used during normal full-color printing.

FIG. 5 is a diagram for explaining a gamma table used for processing of the equal reduction method during full-color toner save printing (see FIG. 4). In the diagram shown in the figure, the horizontal axis is INPUT and the vertical axis is OUTPUT. One line Tb in the diagram represents the numerical value of the gamma table when the toner is not saved (normal printing), and the other line Ta represents the numerical value of the gamma table when the full color toner is saved.
The numerical value of the line Ta when the full color toner is saved is a value obtained by multiplying the numerical value of the line Tb when the toner is not saved and the toner use amount reduction rate.

In the example shown in FIG. 5, a line Ta when the reduction rate is 50% is shown. In the case of the example described with reference to FIGS. 2 to 4, the reduction rate is the total amount of toner used during two-color printing / the total amount of toner used during normal full-color printing = 140/190. It takes a value closer to the line Tb than the line Ta in FIG.
As described above, the gamma table value applied to each color is changed on a pixel-by-pixel basis, and the changed table value is applied in the image processing process for generating output image data used for full-color toner save printing. Is done.

<Embodiment 2>
Next, output image data for full-color printing is generated by the K-reduction method in which the above-mentioned saving condition 1 is set as a target amount of toner consumption equivalent to that of two-color printing, and the saving condition 2 is to reduce only the K (black) component. A toner save operation performed by the printer 20 will be described.
FIG. 6 is a diagram illustrating the amount of toner used during normal printing in the printer 20 according to the embodiment of the present invention.
FIG. 6A shows a printing result in normal printing in which toner save is not instructed, that is, when printing is performed using output image data obtained through appropriate processing without changing the print data to be processed. The result of printing is shown. In the illustrated image of FIG. 6A, only a small portion on which a graph is drawn is a color image.

FIG. 6B is a graph showing the amount of toner used for each color component of C, M, Y, and K of a certain pixel in the output image of FIG. 6A. The total toner usage amount of the pixels shown in the graph of FIG. 6B is calculated from the toner usage amount of each color component, and a total “125” is obtained.
The output image of FIG. 6A is output by full-color printing, as can be seen from the graph of FIG. 6B. Therefore, when the print result is charged, it is charged as full-color printing.

FIG. 7 is a diagram illustrating the amount of toner used during two-color printing in the printer 20 according to the embodiment of the present invention.
FIG. 7A shows output image data used for two-color printing of M and K based on the printing result when toner save of two-color printing is instructed, that is, the same print data as in the full-color printing of FIG. 6A. The printing result when printing is performed using the output image data generated and obtained is shown.

FIG. 7B is a graph showing the amount of toner used for each of the M and K color components in a certain pixel in the output image of two-color printing (FIG. 7A). 7B represents the toner usage amount of the same pixel as the pixel shown in FIG. 6B. The total toner use amount of the pixels shown in the graph of FIG. 7B is calculated from the toner use amounts of the respective color components of M and K, and the total “115” is obtained, and the toner use amount is reduced compared with “125” of FIG. 6B. doing.
The output image in FIG. 7A is an example of a case where charging less expensive than full-color printing may be set when charging the printing result because the amount of toner used is reduced. However, the image quality is lower than the result of full-color printing shown in FIG. 6A, and the boundary between colors is not known depending on the color (see the description with reference to FIG. 12 in the [Background Art] above).

Accordingly, the printer 20 aims to save the same amount of toner as in two-color printing, and can perform a full-color toner save operation for full-color printing by reducing the total amount of toner used by the K reduction method that reduces only K. .
FIG. 8 is a diagram illustrating the amount of toner used during full-color toner save printing in the printer 20 according to the embodiment of the present invention.
FIG. 8A shows the result of printing when full color toner save is instructed, that is, based on the same print data as in the full color printing of FIG. The output results when C, M, Y, and K output image data are generated by the same amount as the above, and printing is performed using the obtained output image data are shown.

FIG. 8B is a graph showing the amount of toner used for each of the C, M, Y, and K color components in a pixel in the output image of full-color toner save printing (FIG. 8A). Note that the pixel in FIG. 8B represents the toner usage of the same pixel as the pixel shown in FIGS. 6B and 7B.
In the graph of FIG. 8B, as indicated by an arrow in FIG. 8B, the usage amount of only K is reduced and C, M, and Y are not reduced. The total toner usage amount of this pixel is C, M, and Y. , K, the total amount of toner used for each color component is “115”, which is equivalent to the two-color printing in FIG.

“K reduction method”
Here, the process of generating output image data in which the amount of toner used is reduced by the K reduction method will be described in more detail.
In the full color toner save printing performed by the printer 20, the reduction amount of the used toner depends on the print data as described with reference to FIGS. The total amount of toner used during color printing is obtained, and the difference between the obtained total amounts of toner used is obtained as the target reduction amount of the total amount of toner used in full-color toner save printing. Further, the amount of toner used for each color component that achieves the target reduction amount thus obtained is determined in units of pixels.

One of the methods for determining the reduction amount of each color component for the toner usage amount that achieves the target reduction amount of the total toner usage amount is the “K reduction method”.
The K reduction method retains color information and does not reduce the C, M, and Y components, and reduces the usage amount of only the K component to achieve the target reduction amount of the total toner usage amount.
In order to perform full-color toner save printing by the K reduction method, it is necessary to generate image data used for this print output. The processing for generating the output image data is performed by the image processing means included in the controller 10.

Specifically, the controller 10 first obtains the total toner use amount in full-color toner save printing from the target reduction amount of the total toner use amount and the total toner use amount when the toner save is not applied.
In addition, a reduction rate to reduce only by the K component toner usage amount is determined so that it becomes the total toner usage amount in the full color toner save printing obtained by the above processing, and the output image data of the K component is generated at the predetermined reduction rate. To do. Therefore, the C, M, and Y components do not require additional processing for toner saving.
By performing the above processing, intended full color toner save printing can be performed.

For example, the K component output image data is generated with the reduction rate determined as described above. For example, the gamma table data used for the gamma correction processing for correcting and outputting the input data is changed according to the toner usage reduction rate. This can be done. The reduction rate of K toner usage is
(K-ΔQ) / K
(Where K is the amount of K used during normal full-color printing, ΔQ is the target reduction amount, that is, “total amount of toner used during normal full-color printing” − “total amount of toner used during two-color printing”)
Is the value to be obtained.
By multiplying the K gamma table value applied during normal printing by the toner use amount reduction rate obtained above, the K gamma table value applied during full color toner save printing can be obtained (see the description of FIG. 5).

K-reduction full-color toner save printing (FIG. 8A) is suitable for use with print data such as that shown in FIG. 6A, which contains little color information (C, M, Y). This is because if the print data contains even a small amount of color information, a charge system that sets a higher charge for monochrome printing than full-color printing for monochrome printing data with little color information and mostly monochrome printing data. For users who want to be expensive and want to keep color information even with a small amount of information, use the K save method toner save to get the desired print result at a low cost. Because it can be obtained.
Further, according to this full-color toner save printing, the entire image becomes thin as much as the amount of toner used for the K component is reduced, but the color information (C, M, Y) can be maintained. It is possible to suppress a defect that occurs in color printing such that the boundary between colors is not known depending on the color (see the description with reference to FIG. 12 in [Background Art]).

<Selecting user saving conditions>
When saving the use of toner by full-color toner save, the method of reducing the toner amount of each color to be used is the equal reduction method (see the first embodiment) or the K reduction method (see the second embodiment, see above). ), The image quality of the printed result also changes.
Therefore, on the premise that the printer 20 has means corresponding to both the uniform reduction method and the K reduction method, one of the above two methods can be selected and used for full color toner saving. Here, an instruction is given by an operation from the outside so that a user or a manager of the device can select a method that is determined to be desirable.
As the instruction, a method by an input operation using a key or the like from the operation panel 24 of the printer 20 and a method using a printing condition instruction function of a printer driver installed in the host PC 40 can be adopted.

When instructing from the operation panel 24 of the printer 20, a small display unit is normally used in the printer, and an operation screen for instructing operation conditions is displayed there, and a toner save selection is displayed on a part of the operation screen. The operation screen is displayed.
When a small display unit is used, a method in which a screen showing an operation condition or the like to be selected is sequentially changed by pressing a button is adopted, and this method is also adopted here.
When the displayed operating condition is selected, a function button such as “OK” is operated to confirm the instruction for selecting the displayed operating condition.

FIG. 9 is a diagram for explaining the transition of the operation screen for instructing full color toner save printing from the operation panel 24.
In the example shown in the figure, when a user calls an operation screen for full color toner save (hereinafter simply referred to as “toner save”) in an operation that is enabled by direct printing or the like, first, whether or not to save toner is determined. A screen D1 for selecting is displayed. Here, when the down (down) button for instructing the transition is pressed without pressing the “OK” button, a transition is made to the operation screen D2 for selecting the next toner save saving condition.
Hereinafter, the saving conditions selected when saving toner are sequentially displayed.
The first saving condition in the transition operation screen D2 is “thin”. Here, when the “OK” button is pressed, a saving condition for maintaining a full-color image and increasing toner save is selected.

The second saving condition in the transition operation screen D3 is “slightly thin”. Here, when the “OK” button is pressed, a saving condition for keeping the full color image and weakening the toner save is selected. Note that “thin” on the operation screen D2 and “slightly thin” on the operation screen D3 are implemented by determining the amount of toner used for each color at a predetermined reduction rate in the same manner as in the above equal reduction method. obtain.
The third saving condition in the operation screen D4 to be transitioned next is “cost priority (equal reduction)”. Here, when the “OK” button is pressed, the operation of performing toner saving while maintaining the full-color image described in the first embodiment is selected.
The fourth saving condition on the operation screen D5 to be transitioned next is “cost priority (K reduction)”. Here, when the “OK” button is pressed, the operation of performing toner saving while maintaining the full-color image described in the second embodiment is selected.
In addition, the expression “cost” in the above “cost priority (equal reduction)” and “cost priority (K reduction)” is used for the user when operating in a billing system in which the billing amount is reduced when printing under this saving condition. This is a representation for easily recognizing the relationship with billing.

When instructing using the print condition instruction function of the printer driver installed in the host PC 40, a computer display is used. Therefore, the configuration of the operation screen for instructing the operation condition is compared with the operation panel of the printer described above. And become free.
The operation conditions and the like to be selected are basically the same as those of the above-described printer operation panel. In addition, the user can accept an operation of specifying an operation condition displayed on the screen and confirming the instruction of the displayed operation condition by operating a function button such as “OK”. Basically, it is not different from the above-described example of the printer operation panel. However, the printer driver needs to describe the operating conditions instructed by the user's operation in the print (PDL) data to be transmitted to the print request destination printer 20.

FIG. 10 is a diagram illustrating a combo box on the operation screen of the printer driver that instructs toner save printing.
In the example shown in the figure, a screen element 241 for setting toner save is provided as one element of a printer driver operation screen for the user to instruct printing conditions. In the screen element 241 for setting the toner save, all items to be selected are expanded in the combo box 242, and one of them is selected, and a function button such as “execute” is operated. To confirm the instruction.
In the combo box 242, all items to be selected “None”, “Thin”, “Slightly thin”, “Cost priority (equal reduction)” and “Cost priority (K reduction)” are the above-mentioned selection items ( Since this is the same as that shown in FIG. In addition, there is an item “user setting” at the bottom of the combo box 242. This is instructed by a method of inputting a toner saving saving condition desired by the user, for example, by a numerical value of a reduction rate. is there.

<Output image data processing flow>
As described above in <Selection of saving conditions by the user>, since the printer 20 has means corresponding to both the uniform reduction method and the K reduction method, the reduction method is selected by a user instruction. The controller 10 of the printer 20 needs to perform an operation according to the user's selection.
Next, a procedure of output image data processing used for full-color toner save printing performed by the controller 10 using a reduction method instructed by the user will be described based on a flow.

FIG. 11 is a flowchart of output image data processing during full-color toner save printing in the printer 20 according to the embodiment of the present invention.
The controller 10 is instructed to save full color toner (cost-priority toner save) in the print data received from the host PC 40, or saves full-color toner (cost-priority toner when a print request such as direct printing is performed through the operation panel 24. When “Save” is instructed, this flow is started and the processing is started.
When the processing is started, the controller 10 first uses the toner when not saving toner (normal printing) and when saving toner (low-cost printing) by non-full-color printing such as monochrome printing or two-color printing conventionally employed. The total amount is calculated (step S101). This calculation is described in FIGS. 2 and 3 of the first embodiment and FIGS. 6 and 7 of the second embodiment, and takes an example of two-color printing as low-cost printing.

However, there are various types of low-cost printing based on non-full-color printing, and it is conceivable that various charging amounts are adopted when operating in a system that charges the printing result, but the illustrated monochrome printing, two-color printing, etc. As described above, when the charging amount is the same when operating in the charging system, the total amount of toner used for low-cost printing with the largest total amount of toner used is used in the subsequent calculation for calculating the toner reduction amount.
By calculating the amount of toner reduction in consideration of such conditions, the rationality of the charge amount can be guaranteed.

  After calculating the total amount of toner used for normal printing and monochrome printing or two-color printing in step S101, the controller 10 next determines whether or not to save the toner evenly for each color by using the uniform reduction method. That is, it is confirmed whether the uniform reduction method or the K reduction method is used (step S102). This procedure confirms the user's instructions described above in <Selecting user saving conditions>.

Next, the controller 10 branches the process according to the confirmation result of step S102, and when the K reduction method is selected (step S102-NO), calculates the reduction rate of the usage amount of K toner (step S103). The processing of this step is performed by executing the processing described in the above “K reduction method” by using the total toner usage for normal printing and monochrome printing or two-color printing calculated in step S101. Find the reduction rate.
Next, the controller 10 multiplies the numerical value of the K gamma table by the K toner usage reduction rate obtained in the previous step, and changes the table value to reflect it in the K output image data (Step S104). .

On the other hand, when the uniform reduction method is selected (step S102-YES), the controller 10 calculates the reduction rate of the usage amount of each color toner (step S105). The processing of this step is performed by executing the processing described in the above “equal reduction method” using the total amount of toner used for normal printing and monochrome printing or two-color printing calculated in step S101. The reduction rate of the toner usage of each color of Y and K is obtained.
Next, the controller 10 changes the table value by multiplying the numerical value of the gamma table for each color by the reduction rate of the toner usage amount for each color C, M, Y, and K obtained in the previous step, thereby changing the table value. This is reflected in the output image data for each color of Y and K (step S106).
By performing step S104 and step S106, when full-color toner save is instructed, the processing procedure that is additionally required in the processing of the output image data is terminated.

  10..Controller, 11..CPU, 12..ROM, 13..RAM, 14..NVRAM, 15..Network I / F, 16..Engine I / F, 17..Operation panel I / F, 20 .. Printer, 23 .. Printer engine, 24 .. Operation panel, 40 .. Host PC.

JP 2002-268861 A

Claims (10)

When forming an image based on print data, in addition to performing a normal operation of forming a full-color image with an appropriate color material usage amount, the color material usage amount in the normal operation is determined according to the saving conditions added to the print data. An image forming apparatus that performs a color material saving operation for forming an image with a color material usage amount reduced by a predetermined amount,
A reduction amount calculation means for calculating a reduction amount of the total amount of color material used in the print data to be processed in pixel units according to the instructed saving conditions;
Based on the print data to be processed, image output data in which the reduction amount calculated by the reduction amount calculation unit is reflected in the total color material usage amount in units of pixels is provided on condition that a full-color image is maintained. Image processing means,
An image forming apparatus. The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the saving condition is a condition for reducing the total amount of color material used when a non-full-color printing saving method including a monochrome printing saving method and a two-color printing saving method is applied. The image forming apparatus according to claim 2,
It is possible to select one of a plurality of saving methods included in the non-full-color printing saving method applied as the saving condition,
An image forming apparatus having means for selecting a method that uses a saving method in which the total amount of color material used is the largest after reduction among a plurality of saving methods included in a non-full-color printing saving method. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus generates the full-color image output data for reducing the total amount of color material used by equalizing the reduction rate of each color component. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus generates the full-color image output data for reducing the total amount of color material used by reducing only the black color component. The image forming apparatus according to any one of claims 1 to 3,
The image processing means generates the full-color image output data for reducing the total amount of color material used by using either a method of equalizing the reduction rate of each color component or reducing only the black color component. With
An image forming apparatus comprising: means for selecting the method for reducing the total amount of color material used in accordance with an instruction given by an external operation on print data to be processed. The image forming apparatus according to any one of claims 4 to 6,
The image processing unit is an image forming apparatus that reduces color components by gamma correction.   A program for causing a computer to function as the reduction amount calculation unit and the image processing unit included in the image forming apparatus according to any one of claims 1 to 7.   A computer-readable recording medium on which the program according to claim 8 is recorded. When forming an image based on print data, in addition to performing a normal operation of forming a full-color image with an appropriate color material usage amount, the color material usage amount in the normal operation is determined according to the saving conditions added to the print data. An image processing method in an image forming apparatus that performs a color material saving operation for forming an image with a color material usage amount reduced by a predetermined amount,
A reduction amount calculation step of calculating a reduction amount of the total amount of color material used in the print data to be processed in units of pixels according to the instructed saving conditions;
On the condition that a full-color image is maintained, image output data in which the reduction amount calculated in the reduction amount calculation step is reflected in the total color material usage amount in pixel units is based on the print data to be processed. An image processing step to be generated;
An image processing method.

Images