JP2011257669A - Image forming apparatus, image forming control method, image forming control program and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for effectively executing a color material saving mode and color material forcible consumption processing while suppressing deterioration of image quality.SOLUTION: In a color complex apparatus 1, a color conversion processing section 21 converts RGB image data into CMYK image data. If a print mode selection section 23 determines that a color material saving mode is selected for the converted CMYK image data based on print set data, a color material saving section 24 determines whether toner consumption for forming an image is less than a predetermined threshold value. If the toner consumption is less than the threshold value, when forcible toner consumption processing is carried out in which an amount of a color material corresponding to the difference between the toner consumption and the threshold value is forcibly consumed, the color material saving section 24 generates, from the CMYK image data, toner-reducing CMYK image data for reducing the toner consumption and toner-reducing CMYK image data for reducing the toner consumption within a range of the toner consumption greater than or equal to the threshold value.

Description

  The present invention relates to an image forming apparatus, an image forming control method, an image forming control program, and a recording medium, and more specifically, an image that effectively performs a color material save mode and a color material forced consumption processing function while suppressing deterioration in image quality. The present invention relates to a forming apparatus, an image forming control method, an image forming control program, and a recording medium.

  In an electrophotographic image forming apparatus such as a copying apparatus, a printer apparatus, a facsimile apparatus, a composite apparatus, etc., in a development process for visualizing an electrostatic latent image formed on a latent image carrier such as a photosensitive member, Development is performed using a two-component developer composed of a carrier and a toner (coloring material) adhering to the carrier, or a one-component developer composed of only a toner without a carrier. As a developing system for supplying these developers to the electrostatic latent image, a contact system in which the developer is brought into contact with the surface of the latent image carrier and the toner is adsorbed by electrostatic force between the electrostatic latent image and a toner are used. There is a non-contact method in which the electrostatic latent image is caused to fly by an electric field effect formed by a developing bias. In any of the methods, the image forming apparatus, when developing processing, balances the charge amount of the toner with the electrostatic amount of the electrostatic latent image due to the electrostatic relationship generated between the latent image and the electrostatic latent image. Is collected in the developing unit in a so-called unused state without being attached to the electrostatic latent image.

  The toner collected in the developing unit may cause the following problems. That is, the toner is agitated and mixed in the developing unit until it is supplied to the electrostatic latent image, or the toner is arranged in the vicinity of the developing roller surface and the developing roller surface that are arranged to face the latent image carrier in the developing unit. Friction occurs between the blades being charged and charging occurs. In particular, in a developing system using a one-component developer, the toner layer is formed into a uniform thin layer on the surface of the developing roller constituted by a metal roller or the like, and the thin-film toner is allowed to fly to the electrostatic latent image. Is done. In this case, the characteristics of the toner, particularly the charging characteristics, deteriorate due to friction between the toner generated on the surface of the blade or the developing roller for thinning or mixing during the conveyance / stirring process. Sometimes. The deterioration of the toner characteristics, particularly the charging characteristics, is caused by the external additives contained in the developer, that is, the additives used for improving the fluidity, triboelectric charge adjustment, and cleaning properties. It is considered that the toner is buried in the toner by friction or stirring.

  When the image forming apparatus includes a toner replenishing tank, when the developing density decreases, new toner is replenished from the toner replenishing tank to the developing unit in order to optimize the density. When mixed with unconsumed toner (hereinafter referred to as residual toner) that is introduced into the developing unit and remains in the developing unit, the residual toner is charged to a reverse polarity due to friction between the new toner and the residual toner. The new toner and the residual toner may be combined and attracted by the background potential of the latent image carrier to cause background contamination.

  In the non-contact development method using toner flying, the amount of charge of the residual toner increases due to friction and stirring over time, and the residual toner remains adsorbed on the surface of the developing roller. Gets worse. As a result, the image quality of the formed image is degraded.

  Therefore, conventionally, in an image forming apparatus, an image having a forced toner consumption function (forced color material consumption function) for forcibly consuming residual toner in order to prevent such a decrease in image density due to toner deterioration. There is a forming device. This forced toner consumption function calculates the printing rate for each image formation, and when the printing rate is smaller than the predetermined printing rate, that is, when the toner consumption is small and the residual toner is large, A predetermined image (for example, a checkered pattern image) that can obtain a toner consumption amount corresponding to the printing rate is formed on the latent image carrier before the next image formation, and the latent image is formed by the cleaning unit without performing the transfer process. This function collects the toner on the carrier and forcibly consumes the toner.

  On the other hand, in recent years, in image forming apparatuses, in order to reduce running costs and improve resource saving, the amount of color material such as toner and ink (hereinafter simply referred to as toner) is suppressed. An image forming apparatus having a color material save mode (hereinafter referred to as toner save mode) for performing image output has appeared. As a method for saving this toner, a method of thinning out pixels every other pixel, There are various methods such as a method of uniformly reducing the density (gradation value). In such a toner save mode, toner can be saved. However, in any method, the image quality such as density reduction is deteriorated. Therefore, when the user wants to prioritize the cost over the image quality, the toner save mode is used. The mode is selected.

  However, when a large amount of originals with a small image area ratio are printed using the toner save processing function, the toner save processing function is used for an original with a small image area ratio. The amount is further reduced. Therefore, toner deterioration is severe, and in the toner save mode, the above-described forced toner consumption is performed. As a result, although the toner saving effect is insufficient, the amount of toner used for the formed image is reduced, so that there is a problem that the image quality level deteriorates to the same extent as normal toner saving. .

  Therefore, conventionally, the toner consumption amount in the toner save mode is suppressed by determining the toner consumption amount in the forced toner consumption processing function based on the toner consumption amount in the normal mode before performing the toner save mode processing. On the other hand, an image forming apparatus that effectively consumes toner has been proposed (see Patent Document 1).

  However, in the prior art described in the above publication, the toner consumption in the forced toner consumption processing function performed to prevent the color material (toner) deterioration is determined based on the toner consumption in the normal mode. Therefore, in the case of the electrophotographic method, in the toner save mode, only a part of the toner that is a deteriorated color material can be consumed by the forced toner consumption processing function, and the forced toner consumption processing may be insufficient. It was. In other words, the toner saving that is the purpose of the toner save mode can be reliably achieved, but the forced toner consumption processing function is limited, and it is necessary to improve the toner deterioration preventing effect.

  Therefore, the present invention performs color material reduction processing that reduces the amount of color material used within a range in which the operation of forced color material consumption processing does not occur, and improves the color material reduction effect while preventing image quality deterioration. An object is to provide a forming apparatus, an image forming control method, an image forming control program, and a recording medium.

  In order to achieve the above object, the present invention provides a predetermined amount of color material used for image formation with respect to output color image data obtained by converting input color image data to form an image using a color material. If the color material usage amount is less than the threshold value, the forced color material consumption process for forcibly consuming the color material difference amount between the color material usage amount and the threshold value is performed. Generating color material reduction output image data for reducing the color material usage amount from the output image data, and reducing the color material usage amount in a range where the color material usage amount is not less than the threshold value The output image data is generated.

  In addition, the present invention acquires the color material reduction degree set for the color material reduction image processing for the input color image data, performs the color material reduction image processing according to the color material reduction degree, When the color material usage amount is less than the threshold value, the color material reduction amount range in which the color material usage amount is greater than or equal to the threshold value is calculated as a corrected color material reduction extent range. It may be characterized in that notification that prompts a change in the degree of color material reduction is made by presenting the fact that it is less than the threshold and the range of correction color material reduction.

  According to the present invention, it is possible to perform color material reduction processing that reduces the amount of color material used within the range in which the operation of forced color material consumption processing does not occur, improving the color material reduction effect while preventing image quality deterioration. Can be.

1 is a block configuration diagram of a color composite apparatus to which a first embodiment of the present invention is applied. FIG. The functional block block diagram of the image processing system of a color composite apparatus. Explanatory drawing of the memory map interpolation in a color conversion process. 6 is a flowchart showing forced toner consumption processing. The flowchart which shows an image process. 6 is a flowchart illustrating forced toner consumption processing in units of copies. The functional block block diagram of the image processing system | strain in the color composite apparatus of 2nd Example. 10 is a flowchart illustrating image processing according to the second embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The range of this invention is unduly limited by the following description. However, not all the configurations described in the present embodiment are essential constituent elements of the present invention.

  1 to 6 are diagrams illustrating a first embodiment of an image forming apparatus, an image forming control method, an image forming control program, and a recording medium according to the present invention. FIG. 1 illustrates the image forming apparatus and the image forming according to the present invention. FIG. 2 is a block diagram of a main part of a color composite apparatus 1 to which a control method, an image formation control program, and a recording medium according to a first embodiment are applied.

  In FIG. 1, a color composite apparatus 1 includes a CPU (Central Processing Unit) 2, an NVRAM (Non-Volatile Random Access Memory) 3, a program ROM (Read Only Memory) 4, a RAM (Random Access Memory) 5, an engine interface 6, The engine 7, the panel interface 8, the operation panel 9, the host interface 10, the disk interface 11, the disk unit 12, the scanner interface 13, the scanner 14, etc. are provided, and the CPU 2, NVRAM 3, program ROM 4, RAM 5, engine interface 6, panel The interface 8, host interface 10, disk interface 11, and scanner interface 13 are connected to the bus 15. The color composite apparatus 1 is connected to a computer PC, which is an external apparatus, via a host interface 10, and exchanges print data, print settings, print results, and the like with the computer PC.

  The program ROM 4 stores a basic program as the color composite apparatus 1, the image formation control program of the present invention, and necessary system data. The CPU 2 uses the RAM 5 as a work memory based on the program in the program ROM 4. Then, each part of the color composite apparatus 1 is controlled to execute basic processing as the color composite apparatus 1, and to execute the image formation control method of the present invention.

  That is, the color composite apparatus 1 includes ROM, EEPROM (Electrically Erasable and Programmable Read Only Memory), EPROM, flash memory, flexible disk, CD-ROM (Compact Disc Read Only Memory), CD-RW (Compact Disc Rewritable), DVD. An image formation control program for executing the image formation control method of the present invention recorded on a computer-readable recording medium such as a (Digital Versatile Disk), an SD (Secure Digital) card, or an MO (Magneto-Optical Disc) is read. The image forming control method for effectively executing forced toner consumption processing (forced color material consumption processing) while appropriately performing toner save mode processing (color material reduction image processing) described later by being introduced into the program ROM 4 or the like. It is constructed as an image forming apparatus provided with an image processing unit for executing the above. This image formation control program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark), an object-oriented programming language, or the like, and is stored in the recording medium. And can be distributed.

  The NVRAM 3 is a non-volatile memory that stores data such as the contents of operation instructions from the operation panel 9. The RAM 5 is used as a work memory for the CPU 2, an input buffer for input data, a page buffer for print data, and a memory for download fonts.

  An engine 7 is connected to the engine interface 6 and communicates with the engine 7 such as commands, status information, and print data.

  The engine 7 uses an electrophotographic engine that uses toner as a color material. Although not shown, the engine 7 is a component necessary for performing color image forming processing on paper based on color drawing data in the electrophotographic system. For example, in the case of the tandem type, a photoconductor, an optical writing unit, a developing unit, a charging unit, a cleaning unit, and the like are provided for each CMYK color along a conveyance path of a sheet as an image forming medium. The engine 7 operates the optical writing unit for each color based on the color drawing data and control signals sent from the engine interface 6 to form an electrostatic latent image for each color on the photoconductor for each color, and develop A toner image of each color is formed by supplying the toner as the color material of each color onto the photoconductor and developing it by the unit. The engine 7 feeds a sheet from the sheet feeding unit between the photoreceptor and the transfer unit, and sequentially superimposes and transfers the toner images on the photoreceptors of the respective colors onto the sheet to form a color toner image. The sheet on which the toner image is transferred is conveyed to a fixing unit, and heated and pressed by the fixing unit to fix the toner image on the sheet, thereby performing an image forming process for a color image.

  An operation panel 9 is connected to the panel interface 8, and the operation panel 9 performs various operations such as a mode of the color composite apparatus 1 and a font switching operation, particularly a toner save mode setting operation (toner save mode setting). Various operation keys for performing on / off, toner save rate setting operation, and the like, and a display (for example, a liquid crystal display) for displaying the state of the color composite apparatus 1 and contents input by the user. Yes. The operation panel 9 may be a touch panel. Panel I / F 14 exchanges signals between CPU 2 and operation panel 9.

  As the host interface 10, Centronics, RS232C, or a network interface is used, and a host device such as a computer PC is connected by a cable or a network. The host interface 10 receives control signals and data sent from the computer PC to the color composite apparatus 1 and sends out status signals from the color composite apparatus 1 to the computer PC.

  A disk unit 12 is connected to the disk interface 11, and the disk interface 11 performs an interface with the disk unit 12 to write data to the disk unit 12 and read data from the disk unit 12.

  The disk unit 12 is, for example, a hard disk, a CD-R (Compact Disc Recordable), a flexible disk, or the like, and stores various data such as font data, programs, and print data under the control of the CPU 2.

  A scanner 14 is connected to the scanner interface 13, and the scanner interface 13 interfaces with the scanner 14. As the scanner 14, for example, an image scanner using a CCD (Charge Coupled Device) is used. The scanner 14 scans a document and reads a color document image with a predetermined resolution.

  When the user inputs a print command in the computer PC, the color composite apparatus 1 determines whether or not to perform image formation (toner save mode processing) in which RGB image data and toner are saved (reduced) and the toner save rate (color material). The print setting data including the setting operation of the degree of reduction), that is, the setting operation of the toner save mode is sent from the computer PC. Input RGB image data (input image data, input color image data) sent from the computer PC through the host interface 10 is divided into three types of objects: characters, graphics, and images, and can be interpreted by the color composite device 1. Therefore, the color composite apparatus 1 performs image processing according to the image formation control program on the RGB object data and converts the RGB object data into object data including CMYK signals. The print setting data includes information regarding various printing conditions designated by the user of the computer PC or automatically set, in particular, the toner save request and the like, and the color composite apparatus 1 performs image processing. At this time, the processing contents are switched with reference to the print setting data. Next, the color composite apparatus 1 interprets the data format of each object, develops them collectively into a CMYK bitmap image of one page, and stores the CMYK bitmap image in the RAM 5 as a page buffer. The color composite apparatus 1 performs the above data processing under the control of the CPU 2, performs halftone processing corresponding to the engine 7 on the processed CMYK bitmap image, and sends it to the engine 7 via the engine interface 6. send.

  The color composite apparatus 1 reads the image formation control program, introduces it into the program ROM 4 and the like, and executes it by the CPU 2 to construct a functional block of the image processing system as shown in FIG. 21, a rasterization process 22, a print mode selection unit 23, a color material saving unit 24, a halftone processing unit 25, and the like are constructed. Therefore, each of these units is a function executed by the CPU 2.

  The RGB color conversion processing unit 21 receives RGB image data, and the color conversion processing unit 21 converts the RGB signal (RGB image data) into a CMYK signal (CMYK image data) that is a color material signal of the engine 7. And output to the rasterization processing unit 22. That is, the RGB color conversion processing unit 21 converts RGB object data into CMYK object data. That is, the RGB color conversion processing unit 21 converts the RGB color signals of the respective object data constituting the RGB image data into CMYK color signals, thereby converting them into CMYK image data constituted by CMYK object data. The RGB color conversion processing unit 21 may switch the color conversion parameters depending on the type of object. The RGB color signals are often 8 bits each, and in this embodiment, the converted CMYK color signals are 8 bits each.

  As a specific color conversion method, the RGB color conversion processing unit 21 uses a memory map interpolation as shown in FIG. 3 to tabulate CMYK signals corresponding to the points obtained by equally dividing the RGB signal, and to create a disk unit 12. Alternatively, an arbitrary RGB signal is converted into a CMYK signal by performing an interpolation process with reference to a color conversion table stored in the NVRAM 3.

  The rasterization processing unit 22 interprets the data format of the object data and collectively converts it into one page of CMYK bitmap image data (output image data, output color image data).

  The halftone processing unit 25 converts the multivalued CMYK bitmap image into a binary or small value CMYK bitmap image that can be output by the engine 7.

  In the image processing, the color multifunction apparatus 1 switches the processing content with reference to the print setting data, and the print setting data includes information on various print conditions designated or automatically set by the user as described above. Is included. This print setting data includes a selection result (toner save mode on / off) as to whether or not to execute the toner save mode.

  The color composite apparatus 1 outputs the binary or small-value CMYK bitmap image subjected to the final image processing to the engine 7 via the engine interface 6.

  Then, the color multifunction apparatus 1 determines whether the toner save mode is selected in the print mode selection unit 23 with reference to the print setting data. In other words, the CMYK image data processed by the writerization processing unit 22 and the print setting data are input to the print mode selection unit 23. The print mode selection unit 23 refers to the print data setting data and sets the toner save mode. Determine whether it is set. The print mode selection unit 23 outputs the CMYK image data passed from the rasterization processing unit 22 to the color material saving unit 24 when the toner save mode is selected, and rasterize when the toner save mode is not selected. The CMYK image data passed from the processing 22 is output to the halftone processing unit 25.

  The color material saving unit 24 performs a normal toner save process (color material save process) and also performs a save amount adjustment process. In other words, the color material saving unit 24 multiplies each 8-bit signal of CMYK by a toner save intensity coefficient of less than 1, thereby reducing each signal value and the amount of toner (color material used for image formation output). Amount).

  Assuming that the signal before the toner save process is C1M1Y1K1, the signal after the toner save process is C2M2Y2K2, and the toner save rate (color material reduction degree) is α (0 <α <1), the toner save is expressed by the following equation (1). The signal before processing can be obtained from C1M1Y1K1, and the signal after toner saving processing can be obtained as C2M2Y2K2.

C2 = (1-α) C1
M2 = (1-α) M1
Y2 = (1-α) Y1
K2 = (1-α) K1 (1)
For example, when the toner save rate is 30%, α = 0.3 is set. The toner save rate α may be a fixed value or may be set as appropriate by the user as will be described later.

  The toner save processing method in the color material saving unit 24 is not limited to the above method, and other methods may be used.

  Further, the color material saving unit 23 determines whether or not the CMYK signal (C2M2Y2K2) after the toner saving process is below the forced toner consumption threshold (threshold). As the forced toner consumption threshold, a minimum toner consumption amount that does not require the forced toner consumption process is set in advance. In other words, in the image formation, if toner exceeding the forced toner consumption threshold is consumed, the toner does not deteriorate. This forced toner consumption threshold is set to P × L, where P is the pixel amount corresponding to the unit paper length, and L is the paper length. In addition, the color material saving unit 23 adds the signal values for each pixel for each color toner to the CMYK signal after the toner save to obtain the toner usage amount for the entire page, and compares it with the forced toner consumption threshold for each color toner. To do. When any one of the CMYK colors is below the forced toner consumption threshold, the color material saving unit 23 performs the toner saving process again, and when all the CMYK colors are above the forced toner consumption threshold. Then, the toner saving process is ended, and the CMYK image data as the processing result is output to the halftone processing unit 25. Note that the pixel amount P corresponding to the unit paper length for determining the forced toner consumption threshold may be set to a different value for each toner when the toner deterioration characteristics differ depending on the toner.

  In the re-processing of the toner save process, the color material saving unit 23 performs toner save processing (for toner save processing) so that the CMYK signal that is below the forced toner consumption threshold does not fall below the forced toner consumption threshold. Redo image processing). Specifically, the color material saving unit 23 lowers the toner saving rate α to a level that does not fall below the forced toner consumption threshold, and redoes the toner saving process. For example, for the sake of clarity, only the C signal will be described. When the C toner usage amount before the toner saving process is Ct1, the toner saving rate is α, and the forced toner consumption threshold is PL, the C toner after the toner saving process is performed. The amount used is Ct2 = (1-α) Ct1. When Ct2 = (1−α) Ct1 <PL, the toner save rate α is changed to a modified toner save rate αk that satisfies (1−αk) Ct1 = PL, that is, αk = 1−PL / Ct1. By performing the save process again, the toner save process is performed so as not to fall below the forced toner consumption threshold.

  Actually, there is at least CMYK4 toner in addition to the C signal. In this case, the toner save rate αk is obtained for all colors, for example, CMYK colors, and the largest one is adopted for all colors. Redo the save process.

  For example, assuming that the amount of C-color toner used before toner save processing is 100%, the toner save rate α is 30%, and the forced toner consumption threshold is 80%, the amount of C-color toner used after toner save processing is 70%, which is below the forced toner consumption threshold of 80%. Here, in order not to fall below the forced toner consumption threshold, it is necessary to make the amount of C-color toner used after toner save processing 80%, and the toner save rate α is set to 100% -80% = 20%. Change to, and redo the toner save process.

  Here, if the image is output without redoing the toner saving process, the C toner usage amount becomes 70%, but then the forced toner consumption function operates and 10% of the toner is consumed. Therefore, although the actual toner saving effect is 20%, an image saved with 70% toner is output. That is, although the toner saving effect is insufficient, an image with a low image quality level due to toner saving is output.

  Therefore, the color material saving unit 24 of the color composite apparatus 1 of the present embodiment performs toner save processing with the toner save rate lowered to 20%, thereby achieving image formation with good image quality while achieving the toner save effect. Do.

  However, when the corrected toner save rate αk is less than 0, the color material saving unit 24 cannot save the toner if the toner save process is executed as it is, and instead increases the toner. The corrected toner save rate αk is set to 0 (αk = 0). That is, in this case, the toner save is not performed, but the forced toner consumption threshold is not reached. In this case, no correction is performed.

  Then, the halftone processing unit 25 converts the multi-valued CMYK bitmap image into a binary or small-value CMYK bitmap image that can be output by the engine 7 and the engine 7 via the engine interface 6. Output to.

  Next, the operation of this embodiment will be described. The color multifunction apparatus 1 according to the present exemplary embodiment performs image formation control processing for saving toner while effectively performing the forced toner consumption processing operation.

  That is, the color composite apparatus 1 forms and outputs image data sent from an external computer PC or image data of a document read by the scanner 14 on a sheet by the engine 7. At this time, the operation on the computer PC Alternatively, it is possible to select an image forming output that saves toner as a toner by an operation on the operation panel 9, and when the amount of toner used is below a predetermined forced toner consumption threshold, toner as a color material is removed. A forced toner consumption process for forcibly consuming is executed.

  That is, when the image forming operation is completed, the CPU 2 acquires the image amount Pi of the color image as shown in FIG. 4 (step S101). The image amount Pi is calculated by counting output image data (output CMYK image data, CMYK bitmap data) sent to the engine interface 6 for each pixel at the end of the image forming operation.

  Next, the CPU 2 acquires the paper length L (step S102). The image amount Pi corresponds to a value in an image forming operation for the sheet length L.

  The CPU 2 calculates a toner consumption amount (forced toner consumption amount) Pc to be consumed in the forced toner consumption process by the following equation (2), where P is a pixel amount to be consumed per unit sheet length.

Pc = P × L-Pi (2)
The CPU 2 determines whether or not the calculated forced toner consumption amount Pc is larger than 0, that is, whether or not the forced toner consumption processing operation needs to be performed (step S104), and the forced toner consumption amount Pc is 0 or less. If there is, it is determined that it is not necessary to perform the forced toner consumption processing operation, and the processing is ended as it is.

  In step S104, if the forced toner consumption amount Pc is larger than 0, the CPU 2 determines that the forced toner consumption operation is necessary, and creates a consumption pattern for consuming the forced toner consumption amount Pc. Step S105), after forming the electrostatic latent image of the created consumption pattern on the photosensitive member and supplying toner from the developing unit to form a toner image, the toner image is not transferred on the cleaning unit without transferring it. The forced toner consumption processing operation to be removed is performed (step S106).

  With this forced toner consumption processing operation, if the amount of toner consumed in the output image is small with respect to the specified consumption (forced toner consumption Pc), the toner of the difference amount from the specified consumption is forced. It is possible to suppress the generation of deteriorated toner in the developing unit.

  Then, when RGB image data (input image data) is input from the computer PC or the scanner 14, the color composite apparatus 1 performs image processing as shown in FIG. 5 to obtain CMYK image data (output image data). The image is output to the engine 7 via the engine interface 6, and the engine 7 is caused to form an image based on the CMYK image data after the image processing. In the following description, the processing of the functional block shown in FIG. 1 will be described, but the hardware is executed by the CPU 2.

  That is, in the color composite apparatus 1, first, the color conversion processing unit 21 converts RGB image data into CMYK image data, and outputs the converted data to the rasterization processing unit 22 (step S201).

  The rasterization processing unit 22 interprets the data format of the object data constituting the CMYK image data and collectively converts it into a one-page CMYK bitmap image (step S202). At this time, the rasterization processing unit 22 interprets the font information and bitmaps it if it is a character object, and interprets vector data and bitmaps it if it is a graphics object. Also, the rasterization processing unit 22 creates a CMYK bitmap image for one page by executing a process of aligning the positions in the page and pasting them as they are for image data, for all objects.

  Next, the print mode selection unit 23 checks the print setting data to determine whether or not the toner save mode is set (step S203). When the toner mode is the toner save mode, the CMYK image data is stored in the color material save unit 23. Output to.

  As described above, the color material saving unit 23 multiplies each CMYK 8-bit signal by a toner save rate α of less than 1, thereby reducing each signal value and reducing the amount of toner used for output. Toner save processing is performed (step S204).

  When performing the toner saving process, the color material saving unit 23 compares the toner usage amount of each color of the entire page with the forced toner consumption threshold of the corresponding color, and the toner usage amount of each color used for image formation corresponds. It is determined whether the color toner is below the forced toner consumption threshold (step S205), and if there is no toner usage amount of the color below the forced toner consumption threshold, the CMYK image data after the toner save process is performed in the halftone processing unit 25. Is output. The halftone processing unit 25 performs a halftone process for converting a multi-value CMYK bitmap image into a binary or small-value CMYK bitmap image that can be output by an engine or the like. 7 to finish the process (step S207).

  In step S205, when there is at least one toner usage amount of the color that is below the forced toner consumption threshold, the color material saving unit 23 sets the forced toner consumption threshold for the CMYK signal that is below the forced toner consumption threshold. Redo the toner save process so that it does not fall below. Specifically, the toner save process is performed again using the modified toner save rate αk in which the toner save rate α is lowered to a level not lower than the forced toner consumption threshold (step S206).

  When the color material saving unit 23 completes the toner saving process, the color material saving unit 23 outputs the CMYK image data after the toner saving process to the halftone processing unit 25, and the halftone processing unit 25 converts the multivalued CMYK bitmap image into the engine or the Then, halftone processing is performed to convert the image to a binary or small CMYK bitmap image that can be output, and the image is output to the engine 7 via the engine interface 6 to end the processing (step S207).

  When the toner save mode is not set in step S203, the print mode selection unit 23 passes the CMYK image data received from the rasterization processing unit 22 to the halftone processing unit 25 without performing the toner save processing in the color material saving unit 24. The halftone processing unit 25 performs halftone processing for converting a multi-value CMYK bitmap image into a binary or small-value CMYK bitmap image that can be output by an engine or the like, via the engine interface 6. It outputs to the engine 7, and a process is complete | finished (step S207).

  As described above, the color composite apparatus 1 according to the present embodiment converts the RGB image data (input image data, input color image data) by the color conversion processing unit 21 in order to form an image using the toner that is the color material. When the print mode selection unit 23 determines that the toner save mode is selected from the print setting data for the CMYK image data (output image data, output color image data), the color material save unit 24 performs image formation. It is determined whether or not the amount of toner used is less than a predetermined threshold (forced toner consumption threshold). If the amount of toner used is less than the forced toner consumption threshold, When the forced toner consumption process for forcibly consuming the difference amount of toner is performed, the color material saving unit 24 reduces the toner usage amount from the CMYK image data. Generates the CMYK image data, the toner usage is generating CMYK image data for toner reduction to reduce the toner usage in a range of more forcible toner consumption threshold.

  Therefore, when the toner save mode is used, the forced toner consumption processing function is not limited, and it is possible to prevent the image deterioration from being increased although the toner save effect is insufficient. That is, when the toner save mode is selected, the toner in the toner save mode is used so that the toner amount used for the image forming output does not fall below the minimum toner amount (forced toner consumption threshold) that does not require forced toner consumption processing. By adjusting the save rate, when using the toner save mode in the color composite apparatus 1 having the forced toner consumption processing function, the image quality is improved while improving the toner save effect without restricting the forced toner consumption function. Can be prevented.

  In the above description, the forced toner consumption process and the toner save rate adjustment process are performed for each page of input image data or output image data. However, these processes are not limited to the process performed for each page. For example, it may be performed in units of copies, daily units, or the like. For example, when 10 copies of a document consisting of 5 pages are printed out, the forced toner consumption processing and toner save rate adjustment processing are executed in units of 5 pages.

  A case where forced toner consumption processing and toner save rate adjustment processing are performed in units of copies will be described below. First, a case where forced toner consumption processing is performed in units of copies will be described with reference to FIG. In FIG. 6, the same step numbers are assigned to the same processing steps as the processing steps of FIG. 4, and the description thereof is simplified.

  In the forced toner consumption processing for each copy, the CPU 2 first initializes a consumption amount (forced toner consumption amount) Pc for forced toner consumption (Pc = 0) (step S301), and sets the color image amount Pi. Obtain (step S101).

  Next, the CPU 2 acquires the paper length L (step S102), and calculates the forced toner consumption amount Pc, where P is the pixel amount to be consumed per unit paper length. However, the value of the forced toner consumption amount Pc is updated by adding the obtained value to the original value of the forced toner consumption amount Pc (step S302). That is, the forced toner consumption amount Pc is calculated by the following equation (3).

Pc = Pc + PxL-Pi (3)
When the forced toner consumption amount Pc is calculated, the CPU 2 determines whether or not the color image data to be processed is the image data of the last page in one copy (step S303). Returning to FIG. 5, the same processing as described above is performed from the acquisition of the image amount Pi (steps S101, S102, S302, S303).

  In step S303, if the color image data to be processed is the last page in one copy, the CPU 2 determines whether or not the calculated forced toner consumption Pc is greater than 0 (step S104). If the forced toner consumption amount Pc is 0 or less, it is determined that it is not necessary to perform the forced toner consumption process, and the process ends.

  If the forced toner consumption amount Pc is greater than 0 in step S104, the CPU 2 determines that the forced toner consumption process is necessary, and creates a consumption pattern for consuming the forced toner consumption amount Pc. (Step S105) After forming the electrostatic latent image of the created consumption pattern on the photosensitive member and supplying toner from the developing unit to form a toner image, the cleaning unit does not transfer the toner image. The forced toner consumption operation to be removed in step S106 is performed (step S106).

  With this forced toner consumption processing operation, when the consumption amount of toner consumed in one image output process is smaller than the prescribed consumption amount (forced toner consumption amount Pc), the forced toner consumption amount Pc It is possible to forcibly consume the difference amount of toner and suppress the generation of deteriorated toner in the developing unit.

  Corresponding to the forced toner consumption processing operation, image processing including toner save processing is performed in units of copies. Since the image processing in units is the same as that in FIG. 5, the image processing in units is not shown. However, in order to adjust the toner save rate α in units, each step is performed in units. In the following, the image processing when it is performed in units of copies will be described with reference to FIG.

  In the image processing for each copy, steps S201 to S204 in FIG. 5 are the same processing. In step S205, the CPU 2 determines the pixel amount P to be consumed per unit sheet length, the sheet length L, and one copy. The forced toner consumption threshold is set by P × L × n, where n is the number of pages per page. Further, as for the toner usage amount, the CPU 2 calculates the toner usage amount for the entire copy by summing the values for each pixel for each color toner for the CMYK signal after the toner save.

  In step S205, when any one of the CMYK colors is below the forced toner consumption threshold, the CPU 2 performs the toner save process again in step S206 so as not to fall below the forced toner consumption threshold.

  In this way, it is possible to determine whether or not forced toner consumption processing is necessary for the entire copy. As a result, when image output is performed in toner save mode, even if the toner consumption is reduced to the extent that forced toner consumption processing is required on a specific page in one copy, the toner consumption on other pages is moderately generated. Then, it is not necessary to perform forced toner consumption processing for the entire copy, and wasteful toner consumption can be suppressed. That is, in actual image formation, generally, there are not so many color images that have a toner amount that is small enough to require forced toner consumption processing, and it is determined whether or not forced toner consumption processing is necessary for one copy as a whole. , Wasteful toner consumption can be suppressed.

  7 and 8 are diagrams showing a second embodiment of the image forming apparatus, the image forming control method, the image forming control program, and the recording medium of the present invention, and FIG. 7 is the image forming apparatus and the image forming of the present invention. It is a functional block block diagram of the image processing system of the color composite apparatus 30 to which the second embodiment of the control method, the image formation control program, and the recording medium is applied.

  This embodiment is applied to a color composite apparatus 30 similar to the color composite apparatus 1 of the first embodiment. In the description of this embodiment, the color composite apparatus 1 shown in FIGS. The same constituent parts will be described using the same reference numerals, and the parts not shown will be described using the reference numerals used in FIGS. 1 and 2 as they are.

  In FIG. 7, a color composite device 30 has the same hardware configuration as that of the color composite device 1 of the first embodiment. As a functional block of the image processing system, a color conversion processing unit 21 and rasterization processing similar to those in FIG. And a color material saving unit 31, a user notification unit 32, and the like.

  The color composite apparatus 30 according to the present embodiment selects the toner save mode and performs the toner save process by operating the operation panel or the computer PC that transmits the image data to be formed. Toner save rate can be set.

  The color conversion processing unit 21, the rasterization processing unit 22, the print mode selection unit 23, and the halftone processing unit 25 of the color composite apparatus 1 according to the present embodiment are the same as those in the first embodiment, and description thereof is omitted.

  The color material saving unit 31 performs the same toner saving process as in the first embodiment, but determines whether or not the CMYK signal after the toner saving process is below the forced toner consumption threshold value. If any one of them is below the forced toner consumption threshold, a range of the toner save rate α that does not fall below the forced toner consumption threshold is obtained for the CMYK signal that is below the forced toner consumption threshold. Specifically, the color material saving unit 31 obtains a corrected toner save rate αk in which the amount of toner used in image formation is the same as the forced toner consumption threshold, and the corrected toner save rate αk or less is within the range of the toner save rate α. Asking. Then, the color material saving unit 31 notifies the user who has obtained the toner save rate change notification that urges the user to change the toner save rate α that clearly indicates the range of the toner save rate α that does not need to be executed. The message is displayed on the user notification unit 32, and the process ends. In this case, the color composite apparatus 30 stops the image forming operation process itself when the toner save rate change notification is sent to the user notification unit 32. That is, the user inputs the print command again, and at this time, the toner save rate is notified and the toner save rate α is set appropriately within the range.

  Next, the operation of this embodiment will be described. The color composite apparatus 30 of this embodiment can set the selection of the toner save mode and the toner save rate in the toner save process.

  That is, in the color composite apparatus 30, first, the color conversion processing unit 21 converts the RGB image data into CMYK image data, and outputs it to the rasterization processing unit 22 as in the case of the first embodiment (step S401). The rasterization processing unit 22 interprets the data format of the object data constituting the CMYK image data and converts them into a single page CMYK bitmap image in the same manner as in the first embodiment (step S402). .

  Next, the print mode selection unit 23 checks the print setting data and determines whether or not the toner save mode is set (step S403).

  If the toner save mode is not set in step S403, the print mode selection unit 23 passes the CMYK image data received from the rasterization processing unit 22 to the halftone processing unit 25 without performing the toner saving process in the color material saving unit 24. The halftone processing unit 25 performs halftone processing for converting the multi-value CMYK bitmap image into a binary or small-value CMYK bitmap image that can be output by the engine 7 or the like, via the engine interface 6. Output to the engine 7 (step S404). The engine 7 forms an image on a sheet based on the received CMYK bitmap image and ends the process (step S405).

  In step S403, when the toner save mode is selected, the print mode selection unit 23 outputs the CMYK image data passed from the rasterization processing unit 22 to the color material save unit 23, and the color material save unit 31 performs the above-described process. The CMYK 8-bit signals are multiplied by a toner save rate α of less than 1, thereby reducing each signal value and performing toner save processing for reducing the amount of toner used for output (step S406). Further, when the color material saving unit 31 performs the toner saving process, the toner usage amount of each color of the entire page is compared with the forced toner consumption threshold value of the corresponding color, and the toner usage amount of each color used for image formation is determined. It is determined whether or not the corresponding toner is below the forced toner consumption threshold (step S407), and if there is no toner usage amount of the color that is below the forced toner consumption threshold, the halftone processing unit 25 receives the CMYK after the toner save process. Output image data. The halftone processing unit 25 performs halftone processing for converting a multi-value CMYK bitmap image into a binary or small-value CMYK bitmap image that can be output by the engine 7 or the like, via the engine interface 6. The image is output to the engine 7 (step S404), and the engine 7 forms an image on a sheet based on the CMYK bitmap image and ends the process (step S405).

  In step S407, when there is even one toner usage amount of the color that is below the forced toner consumption threshold, the color material saving unit 31 sets the forced toner consumption threshold for the CMYK signal that is below the forced toner consumption threshold. The range of the toner save rate α that is not lower is obtained. Specifically, as in the first embodiment, the color material saving unit 31 obtains a corrected toner save rate αk in which the toner usage amount is the same as the forced toner consumption threshold, and forces the corrected toner save rate αk or less. It is obtained as a range of the toner save rate α that does not require execution of toner consumption processing.

  When the color material saving unit 31 obtains the range of the toner save rate α, the color saving unit 31 explicitly indicates the range of the toner save rate α that does not require execution of the forced toner consumption process to the user notification unit 32 and changes the toner save rate. An urging toner save rate change notification message is displayed (step S409), the image forming operation is stopped, and the process is terminated (step S410). This message displays the display of the user's computer PC as the user notification unit 32 or the display of the operation panel of the color composite apparatus 30 as the user notification unit 32 via the host interface. The user sees the toner save rate change notification message, inputs the print command again, and at this time, the range of the toner save rate α that does not require execution of the forced toner consumption process notified of the toner save rate. Set as appropriate.

  In this case, the toner save rate change notification message to the user notification unit 32 may include a message inquiring whether or not the toner save process can be executed with the specified toner save rate. In this case, when the color material saving unit 31 is instructed to execute the toner saving process at the designated toner saving rate, the color material saving unit 31 performs the toner saving process at the designated toner saving rate, and based on the CMYK after the toner saving processing. Image formation.

  As described above, the color composite device 30 according to the present exemplary embodiment acquires the toner save rate (the degree of color material reduction) set for the toner reduction image processing with respect to the input color image data, and the toner usage amount is the forced toner. If the toner consumption is less than the consumption threshold, the toner save rate range in which the toner usage is equal to or greater than the forced toner consumption threshold is calculated as the corrected toner save rate (corrected color material reduction) range. The notification that prompts the change of the toner save rate by presenting the fact that it is less than the forced toner consumption threshold and the corrected toner save rate range is provided.

  Therefore, if the user sets the toner save rate too large in the toner save mode, forced toner consumption processing is executed and the toner save effect can be prevented from becoming smaller than the set value, thereby preventing image quality deterioration. However, the toner reduction effect can be improved.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to that described in the above embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

  The present invention is used for an image forming apparatus, an image forming control method, an image forming control program, and a recording medium such as a printer, a copying machine, a facsimile machine, and a composite apparatus having a color material saving processing function and a forced color material consumption function. be able to.

1 Color compound device 2 CPU
3 NVRAM
4 Program ROM
5 RAM
6 Engine interface 7 Engine 8 Panel interface 9 Operation panel 10 Host interface 11 Disk interface 12 Disk unit 13 Scanner interface 14 Scanner 15 Bus 21 Color conversion processing unit 22 Rasterization processing 23 Print mode selection unit 24 Color material saving unit 25 Halftone processing unit 30 Color Compound Device 31 Color Material Saving Unit 32 User Notification Unit PC Computer

JP 2007-108623 A

Claims (7)

Image conversion means for converting input image data into output image data for forming an image using a color material;
Determination means for determining whether or not to perform color material reduction image processing for reducing the amount of color material used;
When the determination unit determines to perform the color material reduction image processing, the color material reduction processing for generating output material data for color material reduction that reduces the color material usage amount from the output image data converted by the image conversion unit. Means,
Color material usage amount determination means for determining whether or not the usage amount of the color material used in image formation based on the output image data is less than a predetermined threshold;
When the color material usage amount is less than the threshold value, forced color material consumption means for forcibly consuming a color material amount of difference between the color material usage amount and the threshold value;
With
The image forming apparatus, wherein the color material reduction processing unit generates the color material reduction output image data for reducing the color material use amount in a range where the color material use amount is equal to or greater than the threshold value. The image forming apparatus includes:
Color material reduction degree acquisition means for acquiring the color material reduction degree set for the color material reduction image processing for the input image data;
A predetermined notification means;
With
The color material reduction processing means includes
When the color material usage amount is less than the threshold value, the color material reduction amount range in which the color material usage amount is greater than or equal to the threshold value is calculated as a corrected color material reduction extent range. The image forming apparatus according to claim 1, wherein the notification unit is configured to output a notification prompting a change in the degree of color material reduction by presenting the fact that it is less than the threshold and the range of the corrected color material reduction. The color material reduction processing unit generates the output image data for color material reduction for reducing the color material usage amount in a range where the color material usage amount is equal to or more than the threshold for each page of the output image data.
The color material usage amount determining unit determines whether the color material usage amount is less than the threshold value for each page or part of the output image data,
The forced color material consumption means forcibly consumes a color material of a difference between the color material usage amount and the threshold when the color material usage amount for each page or each copy is less than the threshold value. The image forming apparatus according to claim 1 or 2.   The input image data and the output image data are color image data, and the image conversion means, the color material reduction processing means, the color material usage amount determination means, and the forced color material consumption means The image forming apparatus according to claim 1, wherein processing is performed for each color. An image conversion processing step for converting input image data into output image data for forming an image using a color material;
A determination processing step for determining whether or not to perform color material reduction image processing for reducing the amount of color material used; and
If it is determined in the determination processing step that the color material reduction image processing is performed, output image data for color material reduction that reduces the color material usage amount is generated from the output image data converted in the image conversion processing step. Color material reduction processing steps to be performed;
A color material usage amount determination processing step for determining whether or not the usage amount of the color material used in image formation based on the output image data is less than a predetermined threshold;
If the color material usage amount is less than the threshold value, a forced color material consumption processing step for forcibly consuming a color material amount of difference between the color material usage amount and the threshold value;
Have
The color material reduction processing step generates the color material reduction output image data for reducing the color material usage amount in a range where the color material usage amount is equal to or greater than the threshold value. On the computer,
Image conversion processing for converting input image data into output image data for image formation using color materials;
Determination processing for determining whether or not to perform color material reduction image processing for reducing the amount of color material used;
When it is determined that the color material reduction image processing is performed in the determination processing, a color that generates output material data for color material reduction that reduces the color material usage amount from the output image data converted by the image conversion processing Material reduction processing,
A color material usage amount determination process for determining whether or not the usage amount of the color material used in image formation based on the output image data is less than a predetermined threshold;
When the color material usage amount is less than the threshold value, a forced color material consumption process for forcibly consuming a color material difference amount between the color material usage amount and the threshold value;
As well as
In the color material reduction process, the image forming control program for generating the color material reduction output image data for reducing the color material usage amount in a range where the color material usage amount is equal to or more than the threshold value.   A computer-readable recording medium on which the image forming control program according to claim 6 is recorded.

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