JP5402382B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an ink jet system such as a printer, a copier, and a FAX.

  Composite black printing using color ink has been proposed (see, for example, Patent Document 1). Composite black printing is to express black color by combining color inks. Therefore, even if monochrome printing continues without performing color printing, the color ink recording head discharges color ink by performing composite black printing. As a result, the nozzles of the color ink recording head are not clogged by drying.

While composite black printing can prevent clogging of the nozzles of the color ink recording head, it has a larger amount of processing data than printing using only black ink (black printing). Therefore, there is a problem that the productivity of composite black printing is lower than the productivity of black printing. Therefore, an item (for example, a check box) that can select whether or not to apply composite black printing is provided in the user interface so that the user can freely select whether or not to perform composite black printing.
With this configuration, the user must periodically select to perform composite black printing in order to prevent drying of the nozzles of the color ink recording head. However, if a user who frequently performs monochrome printing continues to be in a state where composite black printing is not selected due to an error of the user or the like, there is a problem that the nozzles of the recording head for color ink are clogged.
Therefore, an object of the present invention is to prevent clogging of nozzles of a recording head for color ink even when the user does not select composite black printing.

To achieve the above object, an image forming apparatus having an image forming unit that forms an image on a recording medium based on input image data using black ink and color ink capable of generating composite black. An input unit for inputting whether or not to perform printing with the composite black is input, and the image forming unit inputs to the input unit that the printing is not performed with the composite black, and images on a recording medium for each predetermined number of copies. Provided is an image forming apparatus for forming an image on the gray scale image data with the composite black when the image data in the formation is gray scale .

  The image forming apparatus of the present invention does not cause clogging of the nozzles of the recording head for color ink even when the user does not select composite black printing.

It is the figure which showed the function structural example of the control part of the present Example 1. FIG. (A) of a present Example is the figure which showed an example of the 1st user interface and (B) the 2nd user interface. It is the figure which showed the function structural example of CPU of a present Example. It is the figure which showed the flow of the main processes of CPU of a present Example. It is the figure which showed typically the sheet | seat etc. of a present Example. It is the figure which showed the function structural example of CPU of another Example. It is the figure which showed the flow of the main processes of CPU of another Example. It is the figure which showed typically the paper of another Example. It is the figure which showed the flow of the main processes of CPU of another Example. It is the figure which showed typically the job of another Example. It is the figure which showed the flow of the main processes of CPU of another Example. It is the figure which showed typically the job of another Example. It is the figure which showed the function structural example of CPU of another Example. It is the figure which showed the flow of the main processes of CPU of another Example. It is the figure which showed the function structural example of CPU of another Example. It is the figure which showed the first half part of the main process flow of CPU of another Example. It is the figure which showed the latter half part of FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, the same number is attached | subjected to the process which performs the same process in the structure part and flowchart figure which have the same function in a block diagram, and duplication description is abbreviate | omitted.

  The image forming apparatus of this embodiment is, for example, an ink jet printer. Examples of the image forming apparatus include a printer, a facsimile, a copying apparatus, a plotter, and a complex machine of these.

  FIG. 1 illustrates a functional configuration example of the control unit 60 of the image forming apparatus according to the present exemplary embodiment. The control unit 60 includes a transmission / reception unit 41 for transmitting and receiving data between a microcomputer (hereinafter referred to as “CPU”) 40 that controls the image forming apparatus and an external terminal (for example, a PC), and a control. From a ROM 43 storing necessary fixed information such as a program, an address decoder 44 that outputs a select signal corresponding to an address input from the CPU 41, a printer controller 45 for sending image data to the image memory 42, and a printer controller 45 It has an image memory 42 for storing and storing sent image data, a RAM 46 used as a working memory, etc., and a drive unit 47 for driving each recording head. In the following description, the drive unit 47 and the recording head 6 are collectively referred to as an image forming unit 50.

  The image forming apparatus also includes a black ink carriage that stores black ink and a color ink carriage that stores color (yellow (Y), magenta (M), and cyan (C)) ink. Hereinafter, the black ink may be referred to as K ink, and the color ink may be collectively referred to as CMY ink. The image forming apparatus also includes a recording head that ejects K ink and a recording head that ejects CMY ink. Hereinafter, the recording head for ejecting K ink is referred to as black ink recording head 6K, and the recording heads for ejecting CMY ink are collectively referred to as color ink recording head 6CMY. The black discharge head 6k and the color discharge head 6CMY are collectively referred to as a recording head 6.

Further, the image forming unit 50 of the image forming apparatus of the present embodiment forms an image on a recording medium with black ink or composite black. Examples of the recording medium include paper, thread, fiber, leather, metal, plastic, glass, wood, ceramics, and the like.
The image formation also means that an image such as a character, a figure, or a pattern is applied to the recording medium, or that ink is simply landed on the recording medium. In the following description, “recording medium” is “paper” and “image formation” is “printing”. The “number of pages” of the paper is synonymous with the “number of copies” of the recording medium.

Next, composite black will be briefly described. Black ink is basically used for black reproduction, but black can be reproduced in a pseudo manner by combining cyan dots, magenta dots, and yellow dots (these are also referred to as “CMY dots”). This pseudo black reproduction is due to the characteristics of the subtractive color mixing method in which the brightness and saturation decrease each time the colors are overlapped.
In other words, “composite black” is black reproduced using a combination of CMY dots (using each ink of CMY). Hereinafter, black reproduced using only K ink is referred to as “real black”, and black reproduced by adding CMY ink to K ink in four colors is referred to as “four-color mixed black”.

2A and 2B show a first user interface 70 (User interface) and a second user interface 80, which are the input unit 70, respectively. The first user interface 70 is provided in the image forming apparatus so as to be visible to the user. The second user interface 80 is displayed on a monitor of an external terminal (for example, PC) connected to the image forming apparatus.
The first user interface 70 includes an operation unit 72 configured by predetermined operation buttons (enclosed by a broken line), and a display unit 74 on which various information is electronically displayed. The first user interface 70 is input by the user as to whether or not to perform a gray scale printing method (hereinafter referred to as “gray printing method”) with composite black. Gray scale is to express an image with only light and dark colors from white to black.
On the display unit 74 of the first user interface 70, for example, option (A) “print according to the printer driver” or option (B) “composite black print” is electronically displayed as a gray printing method. . The operation unit 72 includes a pair of push buttons 702 and 704, an enter button 706, and the like. Here, the option (A) “print according to the printer driver” is a default setting, and means that printing is performed according to the determination items of the second user interface 80 described later.
The user selects either option (A) or (B). The selection method is determined, for example, by the user selecting option (A) or option (B) by pressing a pair of vertical movement push buttons 702 and 704 and pressing a determination button 706.
In addition, the second user interface 80 includes an option (C) “gray printing method in K single color (ie, real black)” or option (D) “gray printing method in CMYK four colors (ie, 4) ”is displayed. Option (C) is a default setting. In FIG. 2B, option (C) “K single color” and option (D) “CMYK four colors” are simply shown. The user selects and determines the choice (C) or (D) by, for example, clicking the mouse.

In the image forming apparatus according to the present exemplary embodiment, the first user interface (input unit) 70 is input unless grayscale printing is performed with composite black (hereinafter, referred to as a first predetermined condition), and the predetermined condition (hereinafter, referred to as a first predetermined condition). When the second predetermined condition is satisfied, the image forming unit 50 forcibly performs composite printing on the paper. When the first predetermined condition and the second predetermined condition are satisfied, the user needs to set the image forming apparatus to perform composite black printing.
Although there are various second predetermined conditions, in the first embodiment, the second predetermined condition is “image data is grayscale data on (another) sheet for each predetermined page”. That is, the image forming unit 50 according to the first exemplary embodiment is grayscale data for a sheet that satisfies the first predetermined condition and has a total number of pages corresponding to a multiple of p (p is a natural number of 2 or more). Print with composite black. The total number of pages means the total number of pages when the sheet printed by the image forming apparatus for the first time (for example, for the first time after factory shipment) is one page. Also, when the image data is grayscale data, the image data is color data, but when the user selects to perform grayscale printing through a third user interface described later, the image data is grayscale. Including the case of scale data.

  Other second predetermined conditions will be described in Examples 2 to 5.

FIG. 3 shows a block diagram of a functional configuration example of the CPU 40 in the image forming apparatus according to the first embodiment. FIG. 4 shows a flowchart of processing of the CPU 40 of the first embodiment. FIG. 5 schematically shows a sheet to be printed. In the following description, it is assumed that the natural number p = 5. That is, as shown in FIG. 5, the total number of pages is 5th page, 10th page, 15th page, 20th page,..., 100th page, 105th page, 110th page,. When the image data is grayscale data on a certain sheet, the image forming unit 50 performs composite black printing. Details will be described below.
Information about the option (A) or (B) selected by the first user interface 70 is stored in the storage unit 102 in advance. The information is, for example, a flag. For example, when the option (A) is selected, a first flag indicating “print according to the printer driver” is stored in the storage unit 102. When the option (B) is selected, “composite” is selected. A first flag indicating that “black printing is to be performed” may be stored in the storage unit 102. In this example, it is assumed that the option (A) “print according to the printer driver” continues to be selected due to a user error. That is, a flag indicating the option (A) is stored in the storage unit 102 and satisfies the first predetermined condition.
Further, the storage unit 102 stores information on the option (C) “gray printing method is performed in K single color” or the option (D) “gray printing method is performed in CMYK four colors” selected in the second user interface 80. Is remembered. The information is, for example, a flag (hereinafter referred to as a second flag). For example, when the option (C) is selected, a second flag indicating that “gray printing is performed in K single color” is stored in the storage unit 102, and when the option (D) is selected, A second flag indicating that “the gray printing method is performed in four colors of CMYK” may be stored in the storage unit 102.

  First, in step S <b> 2, the acquisition unit 104 acquires a first flag for the gray printing method (that is, the option (A) or (B)) set by the user from the storage unit 102. In step S <b> 4, the acquisition unit 104 acquires the total page total number Q from the storage unit 102. Here, the total number of pages is the total number of pages printed by all past jobs (that is, jobs before the current job). In this example, the total number Q of pages is described as “104”.

  The authorization unit 106 authorizes the total number of pages R of the current sheet in the current job. That is, the authorization unit 106 authorizes how many pages the current total page number R is. In this example, as shown in FIG. 5, the current number of pages is R = 104 + 1 = 105. In step S6, the first determination unit 108 determines whether or not the current total page number R (= 105) is a multiple of the natural number p (= 5). Since the current total page number R is a multiple of p, the answer is Yes in step S6, and the process proceeds to the next step S8.

  In step S8, the setting unit 110 sets the first flag of the gray printing method in the storage unit 102 to the composite black method. In this example, since the option (A) “print according to the printer driver” is selected by the user, the setting unit 110 forcibly sets the first flag as a flag indicating “composite black printing”. Set to. After step S8 ends, the process proceeds to step S10.

  Next, in step S10, the second determination unit 112 determines whether the input image data is color data or grayscale data in the current job. In FIG. 4, grayscale data is simply referred to as gray data.

  Here, the grayscale data is image data that is not color data, that is, image data in which the yellow element, the magenta element, and the cyan element are all zero. Whether the color data is grayscale data or not is determined by the second determination unit 112 when the yellow element, magenta element, and cyan element are all 0, the second determination unit 112 determines that the data is grayscale data. Otherwise, the second determination unit 112 may determine that the data is color data.

  If No in step S10, that is, if the second determination unit 112 determines that the image data is color data, the process proceeds to step S12, and the data generation unit 114 generates color data from the CMYK ink data. To do.

  If Yes in step S10, that is, if the second determination unit 112 determines that the image data is grayscale data, the process proceeds to step S14. In step S14, the third determination unit 113 determines whether the gray printing method is a method using composite black or a method according to the printer driver. Specifically, the third determination unit 113 acquires the content indicated by the first flag stored in the storage unit 102. In this example, since the gray printing method is set to the composite black method in step S8, the third determination unit 113 determines that the gray printing method is the composite black method. That is, Yes in step S14, and the process proceeds to step S16.

  In step S16, the data generation unit 114 generates composite black ink data. When the data generation unit 114 generates ink data in step S16 or step S12 described above, the process proceeds to the next step S18.

  In step S <b> 18, the fifth determination unit 116 determines whether the printing process for the current page has ended. If No in step S18, that is, if the image forming process (printing process) has not been completed for the current page, the process returns to step S10 until the determination in step S18 is Yes (that is, the current page). The process is repeated until all the ink data has been generated.

  If Yes in step S18, that is, if the fifth determination unit 116 determines that the generation of ink data for the current page has ended, the process proceeds to step S20. In step S20, the image forming unit 50 performs printing on the current page based on the ink data for the current page. In step S22, the updating unit 117 updates the total page count Q (= 104) in the storage unit 102 to the current total page number R (= 105).

  The process for the next page starts again from the start, and the contents of the first flag are reset. After step S2, in step S4, the acquisition unit 104 acquires the total page count Q (= 105) from the storage unit 102. The authorization unit 106 authorizes the total number of pages R in the current job. In this example, as shown in FIG. 5, the current total page number R is R = Q + 1 = 106. In step S <b> 6, the first determination unit 108 determines whether or not the current total page number R (= 106) is a multiple of p (= 5). Since the current total page number R is not a multiple of the natural number p (= 5), the answer is No in step S6, and the process proceeds to step S10 without proceeding to step S8. Here, in the gray printing method, as described above, since the user has selected the option (A) “print according to the printer driver”, the first flag in the storage unit 102 is “print according to the printer driver”. To perform ".

It progresses to step S12 or step S14 mentioned above through step S10. When the process proceeds to step S14, the third determination unit 113 determines whether or not the gray printing method is a composite black method. Since the process has not proceeded to step S8, the gray printing method is “print according to the printer driver”. Accordingly, the third determination unit 113 determines that the gray printing method is not the composite black method, No in step S14, and proceeds to step S24.
In step S24, the fourth determination unit 115 determines whether the gray printing method set in the second user interface 80 (printer driver) is K single color (real black) or four color mixed black. Determine. Specifically, the fourth determination unit 115 may acquire and refer to the second flag in the storage unit 102.
If Yes in step S24, that is, if the fourth determination unit 115 determines that the gray printing method is real black, the process proceeds to step S26. In step S <b> 26, the data generation unit 114 generates black monochrome ink data by black monochrome image information processing.

  In the case of No in step S24, that is, if the fourth determination unit 115 determines that the gray printing method is four-color mixed black, the process proceeds to step S12. In step S12, the data generation unit 114 generates CMYK ink data using a color image processing method. And the process of step S18, S20, S22 is performed.

In the above description, the case where the user inputs the option (A) “print according to the printer driver” from the input unit 70 has been described. Next, a case where option (B) “Perform with composite black” is input from the input unit 70 by the user will be described. In this case, in short, when the image data is gray data, composite black printing is performed even if the second predetermined condition is not satisfied. Details will be described below.
First, a first flag indicating that the option (B) “perform with composite black” is stored in the storage unit 102 in advance. In step S <b> 2, the acquisition unit 104 acquires information (first flag) indicating that the option (B) “performed with composite black” set by the user is obtained, and proceeds to step S <b> 6. In step S6, Yes or No is determined. If Yes, the process proceeds to step S8.
In step S8, the setting unit 110 changes the gray printing method to the composite black method. However, the storage unit 102 stores a first flag indicating that the option (B) “perform with composite black”. Therefore, the gray printing method remains unchanged as the composite black method (the first flag is not changed), and the process proceeds to step S10. That is, in step S6, regardless of whether or not the first determination unit 108 determines that the current total page number R is a multiple of the natural number p, the gray printing method is the composite black method. Therefore, when the option (B) is selected by the user and the image data is gray data, the image forming unit 50 performs composite black printing even if the second predetermined condition is not satisfied.

  Thus, even when the composite black printing method is not selected as the gray printing method from the input unit (first user interface) 70 due to a user error, every predetermined page (5 pages in the above example). If the image data is grayscale data, printing is performed with composite black. Therefore, even if the composite black printing is not selected due to a user's error, the nozzles of the color ink recording head are not clogged.

  In addition, even when the image data is color data on the paper for each predetermined page, the color ink recording head ejects the color ink, so that the nozzles of the color ink recording head are clogged. There is no.

FIG. 6 shows a functional configuration example of the CPU 40 of the second embodiment. FIG. 7 shows a flowchart of the CPU 40 of the second embodiment. FIG. 8 schematically shows a sheet to be printed. In FIG. 8, a color printed sheet is indicated by a broken line, and a gray scale printed sheet is indicated by a solid line. Further, the rightmost column shows the number of pages of the paper on which gray scale printing has been performed, and the left side thereof shows the number of pages of the paper on which gray scale printing and color printing have been performed.
In the second embodiment, the second predetermined condition is “a recording medium printed in gray scale for every predetermined number of pages p”. That is, if the first predetermined condition is satisfied, the image forming unit 50 according to the second exemplary embodiment performs composite black printing on a sheet of a predetermined number of pages on a sheet printed in gray scale. For example, as shown in FIG. 8, when p = 5, the image forming apparatus performs composite black printing every five pages on a recording medium printed in gray scale.
6 is different from FIG. 3 in that the arrangement positions of the first determination unit 108, the second determination unit 112, and the certification unit 106 are switched. FIG. 7 differs from FIG. 4 in that step S4 and step S22 are replaced with step S54 and step S72, respectively, and that step S6 and step S10 are interchanged.
In this example, as in the first embodiment, it is assumed that the option (A) “print according to the printer driver” continues to be selected due to a user error. That is, the first flag that satisfies the first predetermined condition and indicates the option (A) is stored in the storage unit 102.
When the processing of step S2 is completed, in step S54, the acquisition unit 104 acquires the total page count Q of the grayscale printed paper from the storage unit 102. In this example, the total number of pages Q of grayscale printed paper is assumed to be “9”. Next, the process proceeds to step S10.
Next, in step S10, the second determination unit 112 determines whether the input image data is color data or gray data in the current job.
If No in step S10, that is, if the second determination unit 112 determines that the image data is color data, the process proceeds to step S12, and the data generation unit 114 generates color data from the CMYK ink data. To do.
In the case of Yes in step S10, that is, if the second determination unit 112 determines that the image data is grayscale data, the process proceeds to step S6. The fact that the second determination unit 112 determines that the image data is grayscale data means that the paper currently being printed is subjected to grayscale printing. The certification unit 106 authorizes the total number of pages R of the paper on which grayscale printing is to be performed on the paper that is currently being printed. In this example, as shown in FIG. 8, the current number of pages is R = 9 + 1 = 10.

In step S <b> 6, the first determination unit 108 determines whether or not the total page number R (= 10) for the current grayscale printing is a multiple of the natural number p (= 5). The first determination unit 108 determines Yes in step S6 because the page number R is a multiple of p, and proceeds to the next step S8.
In step S8, the setting unit 110 sets the gray printing method flag in the storage unit 102 to the composite black method. In this example, since the option (A) “print according to the printer driver” is selected by the user, the setting unit 110 forcibly sets the first flag as a flag indicating “composite black printing”. Set to. After step S8 ends, the process proceeds to step S14.

  In step S14, the second determination unit 112 determines whether the gray printing method is a method using composite black or a method according to the printer driver. In this example, the second determination unit 112 determines that the gray printing method is the composite black method (that is, Yes in step S14). In step S16, the data generation unit 114 generates composite black ink data.

  And it progresses to step S72 through the process of step S18, S20. In step S <b> 72, the update unit 116 updates the current total number Q (= 9) of grayscale printing in the storage unit 102 to the current number of pages R (= 10) subjected to grayscale printing.

  Further, the processing in step S24 and step S26 is the same as that in the first embodiment, and will be omitted. Even the image forming apparatus including the CPU 40 of the second embodiment can achieve the same effects as the first embodiment.

In the third embodiment, the second predetermined condition is “image data is grayscale data in a job for each predetermined number (= natural number p)”. In short, “recording medium” in the second predetermined condition of the first embodiment is replaced with “job”. That is, if the first predetermined condition is satisfied, the image forming unit 50 according to the third exemplary embodiment has the image data for the paper in the job whose total number of jobs is a multiple of p (p is a natural number of 2 or more). If it is grayscale data, composite black printing is performed.
FIG. 9 shows a flowchart of processing of the CPU 40 of the third embodiment. FIG. 10 schematically shows a job input to the image forming apparatus. Further, the functional configuration example of the CPU 40 of the third embodiment is the same as that of FIG. In the following description, it is assumed that p = 5. That is, as shown in FIG. 10, for all sheets in the fifth, tenth, fifteenth, twentieth ... 100th, 105th, 110th ... If the image data is grayscale data, the image forming means 50 performs composite black printing. Further, it is assumed that option (A) “print according to the printer driver” continues to be selected from the first user interface 70 due to a user error. That is, it is assumed that the first predetermined condition is satisfied. Details will be described below.
9 differs from FIG. 4 in that step S4, step S6, step S18, and step S22 are replaced with step S104, step S106, step S118, and step S122, respectively.
In step S <b> 104, the acquisition unit 104 acquires the total number of jobs from the storage unit 102. Here, the total number of jobs refers to the total number of jobs from the first job (for example, for the first time after factory shipment) to the previous job. In step S104, the acquisition unit 104 acquires the total job number Q, and the certification unit 106 authorizes the current total job number R (= Q + 1), that is, what number of jobs the current job is. .
In step S106, the first determination unit 108 determines whether or not the current job number R is a multiple of the natural number p. If Yes in step S106, the process proceeds to step S8, and if No, the process proceeds to step S10.
In step S118, the fifth determination unit 116 determines whether or not the current job has been processed. If Yes in step S118, the process proceeds to step S20. If No, the process proceeds to step S10.
In step S122, the update unit 117 updates the total job total number Q in the storage unit 102 to the current total job number R.
Even in the image forming apparatus including the CPU 40 of the third embodiment, the same effects as those of the first embodiment can be obtained.

In the fourth embodiment, the second predetermined condition is “every predetermined number (= natural number p) of jobs printed in gray scale”. In short, the “recording medium” in the predetermined conditions of the first embodiment is replaced with a “job”. That is, if the first predetermined condition is satisfied, the image forming unit 50 according to the fourth exemplary embodiment performs a composite for all sheets in the job every predetermined number of jobs (= natural number p) in a job printed in gray scale. Perform black printing.
FIG. 11 is a flowchart of the CPU 40 of the fourth embodiment. FIG. 12 schematically shows jobs and the like. The functional configuration example of the CPU 40 of the fourth embodiment is the same as that of FIG. In FIG. 12, a job that has been printed in color is indicated by a broken line, and a job that has been printed in gray scale is indicated by a solid line. In the rightmost column, the number of jobs that have been subjected to gray scale printing is shown, and the number on the left is the number of jobs that have been subjected to gray scale printing and color printing.
When p = 5, the image forming unit 50 according to the fourth exemplary embodiment performs composite black printing for every five jobs in a job printed in gray scale.
FIG. 11 differs from FIG. 9 in that step S104 and step S122 are replaced with step S154 and step S172, respectively, and that step S106 and step S10 are interchanged. In this example, as in the first embodiment, it is assumed that the option (A) “print according to the printer driver” continues to be selected due to a user error. That is, a flag that satisfies the first predetermined condition and indicates the option (A) is stored in the storage unit 102.
When the process of step S2 is completed, in step S154, the acquisition unit 104 acquires the total job number Q of grayscale printed jobs from the storage unit 102.

  In step S10, the second determination unit 112 determines whether the input image data is color data or gray data in the current job. If No in step S10, that is, if the second determination unit 112 determines that the image data is color data, the process proceeds to step S12, and the data generation unit 114 generates color data from the CMYK ink data. To do.

  If Yes in step S10, that is, if the second determination unit 112 determines that the image data is grayscale data, the process proceeds to step S10. The authorization unit 106 authorizes the current number of jobs R for performing gray scale printing. Since it is determined in step S10 that the image data is grayscale data, the current job is a job for performing grayscale printing. Therefore, the authorization unit 106 authorizes the current number R of jobs for grayscale printing as R = Q + 1.

  In step S <b> 106, the first determination unit 108 determines whether or not the current number R of jobs for grayscale printing is a multiple of the natural number p. If the current number R of jobs for grayscale printing is a multiple of p, the result is Yes in step S106, and the process proceeds to the next step S8. Subsequent processing is the same as in the first embodiment and the like is omitted.

  When the drive unit 47 performs grayscale printing for the current job after the processing of step S20 is completed, the current job count Q for which grayscale printing is performed in the storage unit 102 is grayscale printed in step S172. Is updated to the number of jobs R. Even the image forming apparatus including the CPU 40 of the fourth embodiment can achieve the same effects as the first embodiment.

In the fifth embodiment, the predetermined condition is “sheets for each predetermined page in a monochrome job”. That is, the image forming apparatus according to the fifth exemplary embodiment performs composite black printing every predetermined page of the paper in the monochrome job if the first predetermined condition is satisfied. Here, the monochrome job refers to a job for printing a monochrome image even though the image data is color data or grayscale data. For each job, the user can select whether to make a monochrome job from a third user interface (not shown). The third user interface is displayed on the screen of the external terminal (for example, PC).
FIG. 13 shows a functional configuration example of the CPU 40 of the fifth embodiment. FIG. 14 shows a processing flow of the CPU 40 of the fifth embodiment. In FIG. 13, the acquisition unit 104 is replaced with the third determination unit 202 as compared to FIG. 3. Information (for example, the third flag) indicating whether or not to make a monochrome job input from the third user interface is stored in the storage 102 in advance.
In step S200, the sixth determination unit 202 determines whether or not the current job is a monochrome job. Specifically, the sixth determination unit 202 may determine whether or not the current job is a monochrome job with reference to the third flag.
If No in step S200, that is, if the sixth determination unit 202 determines that the current job is a color job, the process proceeds to step S12.
If YES in step S200, that is, if the sixth determination unit 202 determines that the current job is a monochrome job, the process proceeds to step S6. When the processing of step S6 or step S8 by the authorization unit 106, the first determination unit 108, and the setting unit 110 is completed, the process proceeds to step S10. In step S10, the second determination unit 112 determines whether the image data is gray data.
If No in step S10, that is, if the second determination unit 112 determines that the image data is color data, the process proceeds to step S206. In step S206, the data generation unit 114 converts the color data into gray data, and proceeds to step S14.
In Step S10, if Yes, that is, if the second determination unit 112 determines that the image data is gray data, the process proceeds to Step S14. The subsequent processing is the same as in the first embodiment.
Even in the image forming apparatus including the CPU 40 of the fifth embodiment, the same effects as those of the first embodiment can be obtained.

  In the sixth embodiment, as a predetermined condition, “a non-use period of color ink is measured, and this non-use period is larger than a predetermined threshold value”. That is, the image forming apparatus according to the sixth embodiment measures the non-use period of the color ink while satisfying the first predetermined condition, and when the non-use period is larger than a predetermined threshold value, the composite printing is performed. I do. FIG. 15 shows a functional configuration example of the CPU 40 of the sixth embodiment, and FIGS. 16 and 17 show processing flows of the CPU 40 of the sixth embodiment. FIG. 15 differs from FIG. 3 in that the first determination unit 108 is replaced with a seventh determination unit 302 and an eighth determination unit 304 is added.

In step S302, similar to the process in step S2 described above, the acquisition unit 104 receives information (first flag) on the gray printing method (that is, the option (A) or (B)) set by the user from the storage unit 102. get. Acquisition unit 104 of the sixth embodiment, further, to get the current time _{T 1,} the process proceeds to step S304. For example, a time measurement unit (timer) (not shown) is provided in the image forming apparatus, and the acquisition unit 104 may acquire the current time from the time measurement unit.

  Further, as performed in step S310 described later, when color (CMY) ink is used in a job before the current job, the time when the color ink was used most recently is stored in the storage unit 102. Is done.

In step S <b> 304, the acquisition unit 104 acquires a time T < _b > ₂ when the color ink was used most recently in the storage unit 102. And the certification | authentication part 106 functions as a period measurement part which calculates | requires the non-use period of color ink. Specifically, the certification unit obtains a non-use period T of the color ink by T = T ₁ −T ₂ . Then, the process proceeds to step S306.

In step S306, the seventh determination unit 302 determines whether the non-use period T of the color ink is larger than a predetermined threshold value α, that is, whether T (= T ₁ −T ₂ )> threshold value α is satisfied. Determine whether or not. If Yes in step S306, that is, if the period T is greater than α than the threshold value, it means that the color ink has not been ejected from the color ink recording head for a long period of time. Therefore, if Yes in step S306, that is, if the seventh determination unit 302 determines that T> threshold α, the process proceeds to step S8. In step S8, the setting unit 110 sets the gray printing method to the composite black method. Since the subsequent processing is the same as that of the first embodiment, it is omitted.

  After the process of step S20 ends, the process proceeds to step S308. In step S308, the eighth determination unit 304 determines whether CMY ink has been used. The fact that CMY ink is used is not only when color ink is used by composite black printing in step S16 and step S18, but also when color ink is used by printing color ink in step S12 and step S18. Including.

In the case of Yes in step S308, that is, when the eighth determination unit 304 determines that the color ink is used, the acquisition unit 104 acquires the current time T ₂ ′ and stores the latest in the storage unit 102. The time T ₂ when the color ink is used is updated to the current time T ₂ ′. In the printing process for the next and subsequent pages, the updated time T ₂ ′ is used as the time T ₂ when the color ink was used most recently.

  Even the image forming apparatus including the CPU 40 of the fifth embodiment can achieve the same effects as the image forming apparatus of the first embodiment.

  Also, the predetermined conditions described in the first to fifth embodiments can be used in combination.

6 ... print head 40 ... CPU
41: Transmission / reception unit 42 ... Image memory 43 ... ROM
44: Address decoder 46: RAM
47 ... Drive unit 50 ... Image forming means 70 ... First user interface 80 ... Second user interface

JP 2008-162258 A

Claims (2)

In an image forming apparatus having an image forming means for forming an image on a recording medium based on input image data using a black ink and a color ink capable of generating composite black,
It has an input part for inputting whether or not to perform gray scale printing with the composite black,
The image forming means is inputted to the input unit not to perform the composite black, and when the image data in the image formation of the recording medium for each predetermined number of copies is in gray scale, the composite black in the gray scale is input . An image forming apparatus that forms an image on image data . In an image forming apparatus having an image forming means for forming an image on a recording medium based on input image data using a black ink and a color ink capable of generating composite black,
It has an input part for inputting whether or not to perform gray scale printing with the composite black,
The image forming means is input to the input unit not to perform the composite black, and when the image data in the image formation for each predetermined job is gray scale, the composite black is applied to the gray scale image data. An image forming apparatus that performs image formation.

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