JP2014035468A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress uneven consumption of color materials and suppress dilution of images.SOLUTION: An image forming apparatus includes: image forming means for forming an image on a recording medium by using color materials in respective hues on the basis of image data representing an image having a plurality of hues; and hue adjustment means for detecting the remaining amount of color materials to grasp a color material with the least remaining amount and a color material with the largest remaining amount, and correcting the image data according to an adjustment level designated by a user, so as to adjust hue of an area in the image formed on the recording medium for which the color material with the least remaining amount is to be used gradually in a hue direction toward the color material with the largest remaining amount.

Description

 The present invention relates to an image forming apparatus such as a printer, a copier, or a multifunction peripheral.

  A general digital color multifunction peripheral reproduces a full-color image by adjusting, for example, the gradations of four colors of cyan, magenta, yellow, and black. When printing an image, the amount of toner used in most images is not uniform for each color, so that the toner consumption speed is also biased. If the toner of any color falls below a predetermined amount, color reproduction that deviates from the user's intention may occur. Further, when the toner of any color is completely exhausted, there is a problem that printing cannot be performed even though the remaining amount of toner of other colors is sufficient.

  In order to solve such a problem, a method has been developed in which the remaining amount of toner is detected and toner consumption is prevented from being biased for each color. In Patent Document 1 below, for example, when the color of the toner having the smallest remaining amount is yellow, the color component B (blue) of the input image signal is emphasized, and the color of the toner having the smallest remaining amount is magenta. Discloses a method for suppressing the bias in toner consumption for each color by emphasizing G (green) and emphasizing R (red) when the toner color with the least remaining amount is cyan. . Patent Document 1 below also describes a method of reducing toner output by reducing the output value of toner with a small remaining amount.

JP 2009-126096 A

  However, in the former method described in Patent Document 1, it is possible to suppress toner consumption for the toner with the least remaining amount, but the consumption of the second least toner may increase. For example, when the remaining amounts of cyan, magenta, and yellow toners are 10%, 15%, and 70%, respectively, the input image of R (red) that is the color of the opposite hue to cyan that has the least remaining amount in the former method Emphasize the signal. In this case, cyan toner consumption can be suppressed, but magenta and yellow consumption are increased, and magenta (15%), which has the second smallest remaining amount, is also consumed. It will not be resolved.

  Further, in the latter method described in Patent Document 1, since the toner consumption is suppressed by simply reducing the output value of the least remaining toner, the image may become thin, and in some cases, the image may disappear. is there. Furthermore, when the remaining amount of black toner is the smallest, only the latter method can be used, and as a result, it becomes difficult to suppress the consumption of black toner.

 The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an image forming apparatus capable of suppressing uneven consumption of color materials and suppressing image thinning.

  In order to solve the above-described problem, in the present invention, as a first solving means according to an image forming apparatus, the image is recorded on a recording medium using color materials of each hue based on image data representing an image composed of a plurality of hues. The image forming means to be formed on top and the remaining amount of each color material are detected to grasp the least remaining color material and the most remaining color material, and the image data according to the adjustment level designated by the user By correcting the hue, the hue of the area where the least remaining color material should be used in the image formed on the recording medium is adjusted stepwise in the direction of the hue of the most remaining color material. A means of providing a hue adjusting means is employed.

  In the present invention, as the second solving means relating to the image forming apparatus, in the first solving means, the hue adjusting means detects the remaining amount of each color material and selects the most remaining amount when selecting the specific mode. A method is adopted in which the color material with the least amount of color and the color material with the largest remaining amount are grasped and the image data is corrected according to the adjustment level designated by the user.

  In the present invention, as a third solving means relating to the image forming apparatus, a means is used in which the plurality of hues are cyan, magenta and yellow in the first or second solving means.

  In the present invention, as a fourth solving means relating to the image forming apparatus, in the third solving means, the hue adjusting means grasps the color material having the least remaining amount and the color material having the most remaining amount. Based on the result, means for presenting the adjustable range and direction of hue to the user, and presenting the user with a plurality of adjustment levels prepared in stages as selection candidates to prompt the user to select the adjustment level Is adopted.

  In the present invention, as a fifth solving means relating to the image forming apparatus, in the third or fourth solving means, when the plurality of hues include black in addition to the cyan, magenta and yellow. The hue adjusting means corrects the image data according to the adjustment level designated by the user when the color material with the least remaining amount is the black, thereby correcting the image data formed on the recording medium. The method of adjusting the mixing ratio of the black and all other hues in an area where the original black color material should be used is adopted.

  In the present invention, as a sixth solving means relating to the image forming apparatus, in the fifth solving means, the hue adjusting means is stepwise as a selection candidate when the color material with the least remaining amount is black. A means of presenting a plurality of prepared adjustment levels to the user and prompting selection of the adjustment level is adopted.

  According to the present invention, as a seventh solving means relating to the image forming apparatus, in any one of the first to sixth solving means, the hue adjusting means includes the image data corrected by the image forming means. Before forming an image based on the image on the recording medium, a means for previewing the image based on the corrected image data is employed.

 In the present invention, the remaining amount of each color material is detected, the color material with the least remaining amount and the color material with the most remaining amount are grasped, and the image data is corrected according to the adjustment level designated by the user. The hue of the area where the color material with the least remaining amount in the image formed on the recording medium should be used is adjusted stepwise in the direction of the hue of the color material with the most remaining amount. As a result, the consumption of the coloring material with the least remaining amount is suppressed, and the consumption of the coloring material with the most remaining amount increases, so that it is possible to suppress the uneven consumption of the coloring material and to suppress the thinning of the image. .

 According to the present invention, the hue of the area in the image where the least remaining color material should be used is adjusted in the direction of the hue of the most remaining color material. The color of the formed image may be different from what was originally expected, but the degree of adjustment can be changed arbitrarily by the user by specifying the adjustment level, so user convenience is good It is.

1 is a front perspective view illustrating a configuration of main parts of a multifunction peripheral 100 according to an embodiment. 2 is a functional block diagram of a multifunction peripheral 100 according to the present embodiment. FIG. It is the flowchart which showed each process performed in order that the control part 60 implement | achieves a hue adjustment function. It is an example of an adjustment level selection screen for color toners (when the relationship of CMY toner remaining amount is Y <M <C). It is an example of an adjustment level selection screen for color toners (when the relationship of CMY toner remaining amount is C <Y <M). It is an example of an adjustment level selection screen for color toner (when the magnitude relationship between the CMY toner remaining amounts is M <C <Y). FIG. 6 is an example of an adjustment level selection screen for color toner (when the relationship of CMY toner remaining amount is Y <C <M). FIG. FIG. 10 is an example of an adjustment level selection screen for color toner (when the relationship between the CMY toner remaining amounts is M <Y <C). FIG. FIG. 6 is an example of an adjustment level selection screen for color toners (when the relationship of CMY toner remaining amount is C <M <Y). FIG. It is an example of the adjustment level selection screen for black toner.

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Hereinafter, as an image forming apparatus according to the present invention, an electrophotographic multifunction machine having functions such as a copier, a printer, and a facsimile will be described as an example.

 FIG. 1 is a front perspective view illustrating a configuration of a main part of the multifunction peripheral 100 according to the present embodiment. As shown in FIG. 1, a multifunction peripheral 100 reads a document and generates document image data (hereinafter referred to as document image data) of the document, and a document image obtained from the document reading device 1. And a multifunction device main body 2 that forms an image on a printing paper (recording medium) based on data or image data received from an external device via a communication line (hereinafter referred to as received image data).

  The document reading apparatus 1 includes a scanner 10 and an ADF (Auto Document Feeder) 20. The scanner 10 reads a document set on the platen glass 11 or a document automatically fed by the ADF 20, and includes a platen glass 11, a white reference plate 12, a full rate carriage 13, a half rate carriage 14, An optical lens 15 and a CCD (Charge Coupled Devices) sensor 16 are provided.

  The platen glass 11 is a glass plate for setting originals to be read one by one. The white reference plate 12 is a white plate for acquiring white reference data for shading correction. The full-rate carriage 13 is provided below the platen glass 11 so as to be reciprocally movable in the left-right direction (scanning direction) along the platen glass 11 by a carriage transport mechanism (not shown), and emits illumination light obliquely upward. And a mirror 13b that reflects the reflected light of the illumination light toward a half-rate carriage 14 to be described later.

  Similar to the full-rate carriage 13, the half-rate carriage 14 is provided so as to be reciprocally movable in the left-right direction along the platen glass 11 by a carriage conveyance mechanism (not shown), and the incident light from the mirror 13 b of the full-rate carriage 13 is moved downward. And a mirror 14b that reflects incident light from the mirror 14a toward a condenser lens 15 to be described later. The carriage transport mechanism controls the ratio of the movement amount of the full rate carriage 13 and the movement amount of the half rate carriage 14 to 1: 0.5. Thereby, the optical path length of the illumination light until reaching the condenser lens 15 is controlled to be constant.

  When reading an original set on the platen glass 11, the original is scanned by moving the full rate carriage 13 and the half rate carriage 14 in the scanning direction. However, when the original is automatically fed by the ADF 20 described later, The full-rate carriage 13 and the half-rate carriage 14 are placed on standby at a predetermined document reading position, and the document set is moved (conveyed) to continuously scan a plurality of documents.

  The condensing lens 15 condenses incident light from the mirror 14 b of the half-rate carriage 14 and forms an image on the light receiving surface of the CCD sensor 16. The CCD sensor 16 operates in synchronization with a timing signal supplied from a CCD driving unit (not shown), and photoelectrically converts the light received on the light receiving surface to generate an analog voltage signal corresponding to the read document image. Generate and output to AFE (analog front end: not shown). The AFE amplifies the analog voltage signal with a predetermined gain setting value, and then digitally converts the analog voltage signal to generate document image data representing the read document image. Output to the control unit 60 of the main body 2.

  The ADF 20 automatically and continuously feeds a plurality of documents set on the document placement tray 22 one by one, and includes a platen cover 21, a document placement tray 22, a pickup roller 23, a registration roller 24, a platen It comprises a roller 25, a paper discharge roller 26, and the like. The platen cover 21 is provided so as to be openable and closable with respect to the upper surface of the scanner 10. The platen cover 21 serves as a document pressing cover when a document is set on the platen glass 11 for reading, and a pickup roller 23 and a registration roller 24. The platen roller 25 and the paper discharge roller 26 serve as housing cases for members used in the automatic paper feeding mechanism. FIG. 1 shows a state where the platen cover 21 is closed.

  The document placing tray 22 is a tray for setting a document to be read. The pickup roller 23 is a roller for picking up documents set on the document placing tray 22 one by one and carrying them out to the registration roller 24. The registration roller 24 is a roller for conveying the document to the platen roller 25 at a predetermined timing. The platen roller 25 is a roller for transporting the document to the paper discharge roller 26 via a predetermined document reading position. The paper discharge roller 26 is a roller for discharging the original after reading to the outside. The rotation operation of each roller is controlled by the control unit 60 of the multifunction machine main body 2.

  When the image data obtained from the document reading device 1 or received image data received from an external device via a communication line is RGB color space data, the multi-function device body 2 converts the image data into CMYK colors. It has a function of converting it into image data for printing that is spatial data (function of the control unit 60 described later). As is well known, the RGB color space data is a gradation value of a pixel (minimum unit constituting an image) corresponding to each hue of R (red), G (green), and B (blue) which are the three primary colors. The digital data shown.

  The CMYK color space data is a color material for K (key plate: black) for the three primary colors of C (cyan), M (magenta), and Y (yellow) for printing (toner in the multifunction peripheral 100). Is a data that expresses an image by subtractive mixing. In the electrophotographic multifunction peripheral 100, a single toner image is formed by superimposing the developed toner images on the surface of the photoreceptor for each color of CMYK. The toner image of each hue is constituted by a two-dimensional array of toner arrangement points called dots. In other words, the CMYK color space data is digital data that shows in binary values at which position the toner is arranged in the toner image of each hue.

  The MFP main body 2 includes a toner image forming unit 3 that forms a toner image based on the printing image data on the printing paper, and a fixing unit 4 that fixes the toner image on the printing paper to obtain a completed image. A paper transport mechanism 5 for transporting printing paper, and paper feed cassettes 6, 7, and 8 for storing printing paper of various sizes. Further, the multifunction device main body 2 is provided with a manually accessible tray 9 that can be freely opened and closed on the front side, so that the printing paper placed on the manual tray 9 can be transported by the paper transport mechanism 5.

  The toner image forming unit 3 includes an intermediate transfer belt 31, a toner image forming unit F (FY, FM, FC, FK) corresponding to each color of CMYK, a driving roller 32, a tension roller 33, and a secondary transfer. The roller 34 and the cleaner 35 are comprised. The intermediate transfer belt 31 is an intermediate transfer body for primary transfer of toner images of respective hues formed (developed) by the toner image forming units F (FY, FM, FC, FK) one after another. It is stretched around the roller 32 and the tension roller 33, and is configured to rotate clockwise in FIG.

  Each of the toner image forming units F (FY, FM, FC, FK) includes a photosensitive drum Fa, a charging unit Fb, an exposure unit Fc, a developing unit Fd, and a primary transfer roller Fe. A cleaning device and a static eliminator. The photosensitive drum Fa is set in a cylindrical shape, and an electrostatic latent image and a toner image based on the electrostatic latent image are formed on a peripheral surface thereof. The charging unit Fb is disposed so as to face the photosensitive drum Fa and charges the peripheral surface of the photosensitive drum Fa.

  The exposure unit Fc scans the peripheral surface of the charged photosensitive drum Fa to form an electrostatic latent image, and more specifically, the photosensitive drum corresponding to the dot position where the toner is to be disposed. Laser light is applied to the position on Fa. The developing unit Fd develops a toner image based on the electrostatic latent image on the circumferential surface of the photosensitive drum Fa by attaching toner to the circumferential surface of the photosensitive drum Fa.

  The primary transfer roller Fe is disposed to face the photosensitive drum Fa with the intermediate transfer belt 31 interposed therebetween, and primarily transfers the toner image developed on the photosensitive drum Fa to the intermediate transfer belt 31. The secondary transfer roller 34 is disposed so as to face the driving roller 32 with the intermediate transfer belt 31 interposed therebetween, and the toner image transferred on the surface of the intermediate transfer belt 31 (the toner images of the respective colors are superimposed) Secondary transfer is performed from any one of the paper feed cassettes 6, 7, 8 to the printing paper conveyed by the paper conveyance mechanism 5. The cleaner 35 includes a cleaning roller, a cleaning blade, and the like, and removes residual toner from the intermediate transfer belt 31.

  The fixing unit 4 fixes the toner image secondarily transferred onto the printing paper to obtain a completed image, and includes a heating roller 41 that fixes the toner image by applying pressure and heating. The paper transport mechanism 5 includes pick-up rollers 51, 52, and 53 for carrying out the print paper one by one from the paper feed cassettes 6, 7, and 8, and the picked-up print paper in the toner image forming unit 3 (drive rollers 32 and 2). The paper feed rollers 54, 55, and 56 for transporting to the nip portion of the next transfer roller 34), the paper discharge roller 57 for discharging the printing paper after the fixing process by the fixing unit 4 to the outside, and the like. ing. The paper feed cassettes 6, 7, and 8 are attached to the multifunction device main body 2 so as to be freely drawable, and accommodate sheets of various sizes.

  FIG. 2 is a functional block diagram of the multifunction peripheral 100. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 2, reference numeral 60 is a control unit, 61 is an image data memory, 62 is an operation display unit, 63 is a communication I / F, and 64 is a density sensor. Reference numeral 200 denotes an external device (for example, a personal computer or a facsimile machine) that transmits image data to the multifunction peripheral 100.

  The control unit 60 is a microcontroller in which, for example, a CPU (Central Processing Unit) core, a ROM (Read Only Memory), a memory (RAM) such as a RAM (Random Access Memory), an input / output interface, and the like are integrated, and an operation display Based on the operation signal input from the unit 62, the document image data obtained from the document reading apparatus 1, and the received image data received from the external device 200 via the communication I / F 63, the overall operation of the multifunction peripheral 100 (document A document reading operation by the reading device 1, a toner image forming operation by the toner image forming unit 3, a fixing operation by the fixing unit 4, a paper transporting operation by the paper transporting mechanism 5, and the like are controlled.

  Further, as described above, the control unit 60, when the document image data obtained from the document reading device 1 or the received image data received from the external device 200 via the communication line is RGB color space data. The image data also has a function of converting into print image data which is CMYK color space data.

  The image data memory 61 is a rewritable nonvolatile memory such as a flash memory, for example, and the original image data obtained from the image reading device 1 under the control of the control unit 60 or the received image data received from the external device 200. And image data such as the above-described image data for printing.

  The operation display unit 62 includes an operation key unit 62a and a display unit 62b. The operation display unit 62 inputs an instruction according to a user operation and displays various types of information such as information indicating the state of the multifunction device 100. The operation key unit 62a includes hard keys such as a start key, a stop / clear key, a power key, a numeric keypad (numerical value input key), and a function switching key. The function switching key is used to switch the multifunction device 100 to the operation mode of each function when the user uses each of the copy function, print function, scan function, and facsimile function realized by the multifunction device 100. Key. The display unit 62b has a touch panel function, and displays a screen including soft keys.

  The communication I / F 63 is an interface for performing communication between the MFP 100 (specifically, the control unit 60) and the external device 200, and can communicate with the external device 200 via a network such as a LAN (Local Area Network). It is connected.

  The density sensor 64 detects the density of the toner adhering to each photosensitive drum Fa, and outputs the detected density value to the control unit 60. Since there is a correlation between the density of the toner adhering to the photosensitive drum Fa and the remaining amount of toner, by measuring this correlation in advance, each hue can be determined from the output signal (density detection value) of the density sensor 64. It is possible to detect (estimate) the remaining amount of toner (refer to Patent Document 1 for details).

  In other words, in the present embodiment, the control unit 60 stores in advance the correlation data between the density of the toner adhering to the photosensitive drum Fa and the remaining amount of toner in the built-in ROM, and the correlation data and the density sensor 64. And a function for detecting the remaining amount of toner for each hue based on the output signal (density detection value).

  Furthermore, the control unit 60 of the present embodiment detects the remaining amount of each toner, grasps the toner with the least remaining amount and the toner with the most remaining amount, and prints images according to the adjustment level designated by the user. By correcting the data (CMYK color space data), the hue of the area in the image formed on the printing paper where the least remaining toner should be used is shifted in the direction of the hue of the most remaining toner. It has a function as a hue adjustment means (hereinafter referred to as “hue adjustment function”).

Next, the operation of the multifunction device 100 configured as described above will be described.
FIG. 3 is a flowchart showing each process executed by the control unit 60 to realize the above-described hue adjustment function. As shown in FIG. 3, the control unit 60 first determines whether or not the toner deviation suppression mode is selected as the specific mode (step S1).

  Here, for example, in the case of the copy mode, the control unit 60 starts the process of step S1 when it is detected that the document is set on the platen glass 11 or the ADF 20. For example, in the case of the print mode, the control unit 60 When the image data (RGB color space data) is received together with the print instruction signal from the device 200, the process of step S1 is started.

  Further, for example, in the case of the copy mode, the user can arbitrarily set the toner bias suppression mode by pressing a specific soft key displayed on the display unit 62b or a specific hard key provided on the operation key unit 62a. For example, in the case of the print mode, the toner bias suppression mode can be arbitrarily selected by remote operation using the external device 200.

  If “Yes” is selected in step S1 (when the toner bias suppression mode is selected), the control unit 60 detects the remaining amount of toner for each hue of CMYK, and the toner with the least remaining amount and the remaining amount of remaining toner are detected. The toner having a large amount is grasped (step S2). Specifically, the control unit 60 controls the toner image forming unit 3 to attach the toner of each hue to each photosensitive drum Fa, and at this time, the density detection value obtained from the density sensor 64 and the built-in ROM in advance. The toner remaining amount of each hue is detected (estimated) based on the correlation data between the toner density and the toner remaining amount stored in the.

  Subsequently, the control unit 60 determines whether or not the remaining amount of black toner is the smallest (step S3). In the case of “No”, that is, when the remaining amount of any one of the CMY color toners is the smallest. The adjustment level selection screen for color toner is displayed on the display unit 62b in the copy mode, for example, and is displayed on the external device 200 in the print mode, for example (step S4).

  4 to 9 are examples of adjustment level selection screens for color toner. When the remaining amount of any of the CMY color toners is the smallest, the control unit 60 displays an adjustment level selection screen for the color toner based on the result of grasping the toner having the least remaining amount and the toner having the most remaining amount. By displaying, the range and direction in which the hue can be adjusted are presented to the user, and a plurality of adjustment levels prepared in stages as selection candidates are presented to the user to prompt the user to select the adjustment level.

  FIG. 4 is an adjustment level selection screen in a case where the magnitude relationship between the CMY toner remaining amounts is Y <M <C (when the remaining amount of yellow toner is the smallest and the remaining amount of cyan toner is the largest). As shown in FIG. 4, when the magnitude relationship between the remaining amounts of CMY toners is Y <M <C, a range from yellow Y to cyan C is presented as an adjustable hue range on the CMY space. The direction from yellow Y to cyan C is presented as the direction in which the hue can be adjusted. The adjustment levels are presented in five levels from Lv.1 to Lv.5 in ascending order of adjustment. That is, the adjustment level is the largest at Lv.5.

  FIG. 5 is an adjustment level selection screen when the CMY toner remaining amount relationship is C <Y <M (when the cyan toner remaining amount is the smallest and the magenta toner remaining amount is the most). As shown in FIG. 5, when the magnitude relationship between the CMY toner remaining amounts is C <Y <M, a range from cyan C to magenta M is presented as a hue adjustable range in the CMY space. The direction from cyan C to magenta M is presented as the direction in which the hue can be adjusted. Similarly to FIG. 4, the adjustment levels are presented in five levels from Lv.1 to Lv.5 in ascending order of adjustment.

  FIG. 6 is an adjustment level selection screen in a case where the magnitude relationship between the remaining amounts of CMY toners is M <C <Y (when the remaining amount of magenta toner is the smallest and the remaining amount of yellow toner is the largest). As shown in FIG. 6, when the magnitude relationship between the remaining amounts of CMY toners is M <C <Y, a range from magenta M to yellow Y is presented as an adjustable hue range in the CMY space. The direction from magenta M to yellow Y is presented as the direction in which the hue can be adjusted. Similarly to FIG. 4, the adjustment levels are presented in five levels from Lv.1 to Lv.5 in ascending order of adjustment.

  FIG. 7 is an adjustment level selection screen when the relationship between the CMY toner remaining amounts is Y <C <M (when the yellow toner remaining amount is the smallest and the magenta toner remaining amount is the largest). As shown in FIG. 7, when the magnitude relationship between the remaining amounts of CMY toners is Y <C <M, a range from yellow Y to magenta M is presented as an adjustable hue range in the CMY space. The direction from yellow Y to magenta M is presented as the direction in which the hue can be adjusted. Similarly to FIG. 4, the adjustment levels are presented in five levels from Lv.1 to Lv.5 in ascending order of adjustment.

  FIG. 8 is an adjustment level selection screen in a case where the magnitude relationship of CMY toner remaining amounts is M <Y <C (when the remaining amount of magenta toner is the smallest and the remaining amount of cyan toner is the largest). As shown in FIG. 8, when the magnitude relationship of the CMY toner remaining amount is M <Y <C, a range from magenta M to cyan C is presented as an adjustable hue range in the CMY space. The direction from magenta M to cyan C is presented as the direction in which the hue can be adjusted. Similarly to FIG. 4, the adjustment levels are presented in five levels from Lv.1 to Lv.5 in ascending order of adjustment.

  FIG. 9 is an adjustment level selection screen when the CMY toner remaining amount relationship is C <M <Y (when the cyan toner remaining amount is the smallest and the yellow toner remaining amount is the most). As shown in FIG. 9, when the CMY toner remaining amount relationship is C <M <Y, a range from cyan C to yellow Y is presented as an adjustable hue range in the CMY space. A direction from cyan C to yellow Y is presented as a direction in which the hue can be adjusted. Similarly to FIG. 4, the adjustment levels are presented in five levels from Lv.1 to Lv.5 in ascending order of adjustment.

  On the other hand, when “Yes” is determined in step S3 (when the remaining amount of black toner is the smallest), the control unit 60 displays an adjustment level selection screen for black toner, for example, a display unit in the copy mode. For example, in the print mode, it is displayed on the external device 200 (step S5).

  FIG. 10 is an example of an adjustment level selection screen for black toner. When the remaining amount of black toner is the smallest, the control unit 60 displays an adjustment level selection screen for black toner as shown in FIG. 10 so that a plurality of adjustment levels prepared in stages as selection candidates can be displayed to the user. Present and prompt selection of adjustment level. The black toner adjustment level is also presented in five levels from Lv.1 to Lv.5 in ascending order of adjustment.

  After the adjustment level selection screen is displayed by the processing in step S4 or S5, the control unit 60 stores the specified adjustment level in a memory such as a built-in RAM when the adjustment level is specified by the user. (Step S6). For example, in the copy mode, the user arbitrarily selects an adjustment level by pressing a specific soft key displayed on the display unit 62b or a specific hard key provided on the operation key unit 62a. For example, in the print mode, the adjustment level can be arbitrarily selected by remote operation using the external device 200.

  Then, after storing the adjustment level designated by the user in the memory as described above, the control unit 60 starts the printing process in the toner deviation suppression mode (step S7). Specifically, for example, in the copy mode, when the control unit 60 detects that the copy start key is pressed, the control unit 60 instructs the document reading apparatus 1 to read the document set on the platen glass 11 or the ADF 20. As a result, the document reading device 1 reads the document, generates document image data (RGB color space data) representing an image of the read document, and outputs the document image data to the control unit 60.

  The control unit 60 stores the document image data acquired from the document reading device 1 in the image data memory 61 as described above, while converting the document image data into image data for printing which is CMYK color space data, and the printing. The image data is also stored in the image data memory 61. Then, the control unit 60 reads the print image data from the image data memory 61 and corrects the print image data in accordance with the adjustment level designated by the user, so that the control unit 60 originally corrects the most in the image formed on the print paper. The hue of the region where the toner with the least remaining amount should be used is adjusted stepwise in the direction of the hue of the toner with the most remaining amount.

  For example, it is assumed that the remaining amount of each toner is cyan C = 80%, magenta M = 60%, yellow Y = 20%, and black K = 70%. In this case, when an image that consumes the same amount of CMYK is printed by normal processing, the yellow Y toner with the least remaining amount is the earliest. On the other hand, in this embodiment, since the magnitude relationship of the CMY toner remaining amount is Y <M <C, the color toner adjustment level selection screen shown in FIG. 4 is displayed.

  Here, for example, assuming that the adjustment level Lv.1 for color toner is designated by the user, the control unit 60 uses 95% of yellow toner in an area where the original yellow toner is used in the image at 100%. The printing image data is corrected so that the cyan toner is used at 5%, in other words, the mixing ratio of the yellow toner and the cyan toner is Y: C = 95: 5.

  Further, for example, if the adjustment level Lv.5 for color toner is designated by the user, the control unit 60 uses the yellow toner at 5% in the area where the original yellow toner is used at 100% in the image. The printing image data is corrected so that the cyan toner is used at 95%, in other words, the mixing ratio of the yellow toner and the cyan toner is Y: C = 5: 95. In this way, by changing the adjustment level, it is possible to adjust the ratio of use of the toner with the most remaining amount and the toner with the least remaining amount, and to suppress the deviation of the remaining amount for each toner color.

  Further, for example, assume that the remaining amount of each toner is cyan C = 80%, magenta M = 60%, yellow Y = 20%, and black K = 10%. In this case, when an image that consumes the same amount of CMYK is printed by a normal process, the black toner with the least remaining amount is the earliest. On the other hand, in this embodiment, since the remaining amount of black toner is the smallest, the adjustment level selection screen for black toner shown in FIG. 10 is displayed.

  Here, for example, assuming that the adjustment level Lv.1 for black toner is designated by the user, the control unit 60 uses the black toner at 95% in an area where the black toner is originally used at 100% in the image. The printing image data is corrected so that the CMY toner is used at 5%, in other words, the mixing ratio of the black toner and the other color toner is K: CMY = 95: 5.

  Further, for example, if the adjustment level Lv.5 for black toner is designated by the user, the control unit 60 causes the black toner to be used in an area where 100% of the original black toner is used in the image formed on the printing paper. It is used for printing so that the mixing ratio of black toner and all other color toners is K: CMY = 0: 100, so that it is used at 0% and CMY toner is used at 100%. Correct the image data. As a result, when the amount of black toner is the smallest, it is possible to reproduce black by suppressing the consumption of black toner and adjusting the CMY toner consumption accordingly.

  When the control unit 60 corrects the printing image data by the processing as described above, based on the corrected printing image data, the toner image forming operation by the toner image forming unit 3, the fixing operation by the fixing unit 4, and the paper conveyance By controlling the paper conveyance operation by the mechanism 5, an image based on the printing image data is printed on the printing paper.

  If “No” is determined in step S1 (when the toner bias suppression mode is not selected), the control unit 60 performs toner image formation based on normal printing processing, that is, uncorrected printing image data. By controlling the toner image forming operation by the unit 3, the fixing operation by the fixing unit 4, and the sheet conveying operation by the sheet conveying mechanism 5, an image based on the printing image data is printed on the printing sheet (step S8).

 As described above, in the present embodiment, the remaining amount of each toner is detected to grasp the toner with the least remaining amount and the toner with the most remaining amount, and the print image data according to the adjustment level designated by the user. Is corrected in a stepwise manner in the hue direction of the toner that has the least remaining amount in the image formed on the printing paper in the direction of the hue of the toner that has the most remaining amount. As a result, the consumption of the toner with the least remaining amount is suppressed and the consumption of the toner with the most remaining amount is increased, so that it is possible to suppress the uneven consumption of each toner and to suppress the thinning of the image.

  Further, according to the present embodiment, the hue of the area where the toner with the least remaining amount in the image should be used is adjusted in the direction of the hue of the toner with the most remaining amount, so that it is finally formed on the printing paper. The color of the generated image may be different from what was originally expected, but the degree of adjustment can be changed arbitrarily by the user by specifying the adjustment level. is there.

  The multifunction machine 100 according to the embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and can be freely changed within the scope of the present invention.

  For example, before the toner image forming unit 3 forms an image based on the corrected printing image data on the printing paper, the control unit 60 is provided with a function of previewing the image based on the corrected printing image data. Also good. As a result, the user can know how the image changes before printing, and can avoid unnecessary printing. In the copy mode, the control unit 50 causes the display unit 62b to preview the image based on the corrected print image data. In the print mode, the control unit 50 displays the image based on the corrected print image data on the external device 200. To display a preview.

  In addition, when the adjustment level is presented, the control unit 60 may be provided with a function for presenting a recommended adjustment level with a small change in color tone and a high effect of suppressing bias in consumption of each toner based on the remaining amount of each toner. good. Since a general user cannot recognize what kind of image can be obtained immediately from the adjustment level, the user's usability is improved by presenting the recommended adjustment level to the user as described above.

  In the above embodiment, as a method for detecting the remaining amount of toner, toner of each hue is attached to each photosensitive drum Fa. At this time, the density detection value obtained from the density sensor 64 and the built-in ROM of the control unit 60 in advance. The method for detecting (estimating) the remaining amount of toner for each hue based on the toner density stored in FIG. 5 and the correlation data between the remaining amounts of toner is illustrated, but the method for detecting the remaining amount of toner is not limited to this. For example, as another method for detecting the remaining amount of toner, as described in Patent Document 1, prediction is made from a value obtained by cumulatively adding image data for printing (CMYK color space data) obtained from the time of toner replacement for each pixel. The method of doing is also mentioned.

  In the above embodiment, the case where the image forming apparatus according to the present invention is the multifunction peripheral 100 has been described as an example. However, the present invention is also applicable to other image forming apparatuses such as a printer, a copier, and a facsimile. can do. Further, as the image forming apparatus according to the present invention, the MFP 100 using the toner corresponding to each of the four hues CMYK is exemplified, but the present invention further forms an image using the toner corresponding to a plurality of hues. The present invention can also be applied to an image forming apparatus that uses ink or the like as an apparatus or a color material.

  DESCRIPTION OF SYMBOLS 100 ... MFP, 1 ... Document reader, 2 ... MFP body, 10 ... Scanner, 20 ... ADF (Auto Document Feeder), 3 ... Toner image forming unit (image forming means), 4 ... Fixing unit, 5 ... Paper Transport mechanism, 6, 7, 8 ... feed cassette, 60 ... control unit (hue adjusting means), 61 ... image data memory, 62 ... operation display unit, 63 ... communication I / F, 64 ... density sensor, 200 ... external machine

Claims (7)

Based on image data representing an image composed of a plurality of hues, an image forming means for forming the image on a recording medium using a color material of each hue;
By detecting the remaining amount of each color material, grasping the least remaining color material and the most remaining color material, and correcting the image data according to the adjustment level designated by the user, the recording medium Hue adjustment means for adjusting the hue of the area where the least remaining color material in the image formed above should be used in a stepwise manner toward the hue direction of the most remaining color material;
An image forming apparatus comprising:   The hue adjusting means detects the remaining amount of each color material when selecting a specific mode, grasps the least remaining color material and the most remaining color material, and according to the adjustment level specified by the user The image forming apparatus according to claim 1, wherein the image data is corrected.   The image forming apparatus according to claim 1, wherein the plurality of hues are cyan, magenta, and yellow.   The hue adjustment means presents a range and direction of hue adjustment to the user based on the result of grasping the color material with the least remaining amount and the color material with the most remaining amount, and stepwise as selection candidates. 4. The image forming apparatus according to claim 3, wherein a plurality of adjustment levels prepared in the first step are presented to the user to prompt selection of the adjustment level. 5. In the case where black is present in addition to the cyan, magenta and yellow as the plurality of hues,
When the color material with the least remaining amount is black, the hue adjustment unit corrects the image data in accordance with the adjustment level designated by the user, thereby correcting the image data in the image formed on the recording medium. 5. The image forming apparatus according to claim 3, wherein a mixing ratio of the black and all other hues in an area where the black color material should be originally used is adjusted in a stepwise manner.   The hue adjustment unit is configured to prompt the user to select an adjustment level by presenting a plurality of adjustment levels prepared in stages as selection candidates to the user when the color material with the smallest remaining amount is black. Item 6. The image forming apparatus according to Item 5.   The hue adjusting unit displays a preview of an image based on the corrected image data before the image forming unit forms an image based on the corrected image data on the recording medium. Item 7. The image forming apparatus according to any one of Items 1 to 6.

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