JP2009002977A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain printable state for a long time, while avoiding the printing disabled state due to run-out of toner of only certain colors and keeping the tone of original image. <P>SOLUTION: This image forming apparatus includes an image read part 7 for obtaining a printing object data; a printing object image generating part 91 for obtaining overlay data of an overlay image, and combining the printing object data and the overlay data to generate a printing object image; an image forming part 30 for performing printing in toner of two or more colors; sensors SY, SM, SC for detecting the toner residual quantities of the respective colors of the image forming part 30; and a printing control part 93 for causing the image forming part 30 to print the printing object image, wherein the printing object image generating part 91 generates a printing object image by using the ratio of toner residual quantities of toner of the respective colors detected by the sensors SY, SM, SC as the ratio of toner quantities of toner of the respective colors used for the image formation of the overlay image. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a printing unit that performs printing with toners of a plurality of colors.

2. Description of the Related Art Conventionally, color printing using a plurality of colors of toner has been performed in image forming apparatuses such as printers, copiers, fax machines, and multifunction machines. As such an image forming apparatus, as shown in Patent Document 1 below, when printing an image to be printed, toner of a color whose remaining amount is in a near-end state is not used, and only toner of a color whose remaining amount is not in a near-end state is used. The one using is proposed. This image forming apparatus preferentially consumes a toner having a large remaining amount so that it is difficult to generate a toner that is out of toner. In other words, it is possible to prevent printing from becoming impossible due to the loss of only the toner, and to maintain a printable state for a long time.
JP 2000-356873 A

  In the image forming apparatus described in Patent Document 1, although the printable state can be maintained by preferentially using the toner having a large remaining amount, the color of the entire area of the image to be printed changes uniformly. There has been a problem that the color of an image printed on paper differs from the color of the original image.

  The present invention has been made in view of this point, and avoids a situation in which only one color of toner is lost and printing becomes impossible, and the printable state is maintained while maintaining the hue of the original image. The purpose is to maintain for a long time.

The invention according to claim 1 is a print target data acquisition unit that acquires print target data;
Overlay data acquisition means for acquiring overlay data of an overlay image to be superimposed on an image composed of print target data acquired by the print target acquisition means;
A print target image generating unit configured to generate a print target image by combining the print target data acquired by the print target data acquiring unit and the overlay data acquired by the overlay data acquiring unit;
Printing means for printing with toner of a plurality of colors;
Toner remaining amount detecting means for detecting the remaining amount of toner of each color toner of the printing means;
A printing control unit that causes the printing unit to print the printing target image generated by the printing target image generation unit;
The print target image generating means uses the ratio of the toner remaining amount of each color toner detected by the toner remaining amount detecting means as the ratio of the amount of each color toner used for image formation of an overlay image composed of the overlay data An image forming apparatus that generates an image.

  According to this configuration, the print target image generation unit generates the print target image by using the ratio of the toner remaining amount of each color toner detected by the toner remaining amount detection unit as the ratio of the amount of each color toner used for image formation of the overlay image. By doing so, each color toner is used for printing the overlay image at the same ratio as the ratio of the remaining amount of toner. As a result, the amount of toner used in a color that tends to run out of toner is reduced because the remaining amount of toner is low, and the toner of another color is substituted, so that printing becomes impossible due to the loss of any one color of toner. Thus, the printable state with the remaining amount of toner when the remaining amount of toner is detected can be maintained for a long time. Furthermore, according to the generation of the print target image, only the color of the overlay image added to the original image composed of the print target data changes, and the printable state is lengthened without changing the hue of the original image. Can be maintained.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the print target image generating unit determines in advance the ratio of the toner remaining amount of each color toner detected by the toner remaining amount detecting unit. The value of the difficult-to-view color is converted to a predetermined small value, and the toner remaining ratio after the conversion is used as the ratio of the amount of each color toner used for image formation of the overlay image.

  When the plurality of color toners are, for example, cyan, magenta, and yellow, yellow is difficult for humans to visually recognize compared to other colors. Therefore, when the ratio of yellow toner in the overlay image increases, the user visually recognizes the overlay image. However, in the invention according to claim 2, for example, if yellow or the like is determined in advance as a difficult-to-view color, the ratio of the difficult-to-view color is set in the ratio of the amount of each color toner used for image formation of the overlay image. It is possible to keep the image low and to print an overlay image that is easy for the user to see.

  According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the print target image generating unit is configured to display only the color having the largest toner remaining amount detected by the toner remaining amount detecting unit. In order to form an image of an image, the ratio of the amount of each color toner used to form an image of the overlay image is generated.

  According to this configuration, toner of a color having a large amount of remaining toner is preferentially used for generating an overlay image, so that the remaining amount of toner of each color can be made uniform, and the toner of any one color can be eliminated. The printing impossible state is avoided and the printing possible state is maintained for a long time.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the print target image generating unit is configured such that the color with the largest toner remaining amount detected by the toner remaining amount detecting unit is difficult to visually recognize. When the color is not a color, the ratio of the amount of each color toner used for image formation of the overlay image is generated so that only the color having the largest toner remaining amount is used for image formation of the overlay image.

  When the plurality of color toners are, for example, cyan, magenta, and yellow, yellow is difficult for humans to visually recognize compared to other colors. Therefore, when the ratio of yellow toner in the overlay image increases, the user visually recognizes the overlay image. However, in the invention described in claim 4, for example, if yellow or the like is determined in advance as a difficult-to-view color, the overlay image is prevented from being printed only with a color that is difficult for the user to see, such as yellow. An overlay image that can be easily viewed by the user can be printed.

  According to the present invention, it is possible to maintain a printable state for a long time while maintaining the color tone of the original image while avoiding the case where only a certain color of toner is lost and printing becomes impossible.

  Hereinafter, a copying machine 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing an internal configuration of a copying machine 1 according to an embodiment of the present invention. The copying machine 1 is an example of an “image forming apparatus” in the claims.

  The copying machine 1 is a tandem type digital color copying machine. The copying machine 1 discharges an image reading unit 7 that reads an original image, a main body 2 that transfers the original image read by the image reading unit 7 to a recording paper, and a recording paper on which the original image is transferred by the main body 2 The recording paper discharge unit 6 is provided.

  The image reading unit 7 includes a scanner 71 configured by a CCD (Charge Coupled Device) or the like. The image reading unit 7 reads an image of a document placed on the first contact glass 72 by the scanner 71, while sequentially scanning a plurality of documents stacked on the document placement unit 73 to the second contact glass. The image of the original passing through the second contact glass 74 is read at the position of the second contact glass 74.

  The main body unit 2 includes a paper feeding unit 10, an image forming unit 30, a transfer conveyance unit 40, a fixing unit 50, a recording paper conveyance unit 20, and a control unit 9.

  The image forming unit 30 is an example of a “printing unit” in the claims.

  The paper feeding unit 10 has a stack of recording papers P stacked on a paper feeding cassette. The recording paper P stacked on the paper feeding cassettes is fed one by one from the uppermost recording paper P to the recording paper transport unit 20. Paper is fed to the most downstream part of the paper.

  The recording paper transport unit 20 passes the recording paper P fed from the paper feeding unit 10 to the most downstream portion through the image forming unit 30 and the transfer transport unit 40 and the fixing unit 50 in this order by various roller pairs. Then, the recording paper is conveyed to the recording paper discharge unit 6 provided in the vicinity of the most downstream portion of the recording paper conveyance unit 20.

  The image forming unit 30 multiplexly forms a plurality of toner images on the recording paper passed by the recording paper transport unit 20. The image forming unit 30 includes a first image forming unit 30Y that forms a yellow toner image, a second image forming unit 30M that forms a magenta toner image, and a third image forming unit that forms a cyan toner image. A unit 30C and a fourth image forming unit 30K that forms a black toner image are provided. The image forming units 30K, 30C, 30M, and 30Y are arranged in this order in the image forming unit 30 at a predetermined interval along the recording paper conveyance direction.

  Each of the image forming units 30Y, 30M, 30C, and 30K includes a photosensitive drum 31, a charging unit 32, a developing unit 34, and a cleaning unit 35. The charging unit 32, the developing unit 34, and the cleaning unit 35 are all disposed so as to face the peripheral surface of the photosensitive drum 31. The charging unit 32 charges the photosensitive drum 31. The exposure unit 33 forms an electrostatic latent image on the charged photosensitive drum 31. The developing unit 34 develops the formed electrostatic latent image and creates a toner image on the photosensitive drum 31. The toner image thus formed is transferred from the photosensitive drum 31 to the recording paper that is conveyed to the transfer conveying unit 40 and passed to the position of the photosensitive drum 31.

  The developing unit 34 includes a toner storage unit 341. The toner storage portions 341 of the image forming units 30Y, 30M, 30C, and 30K store yellow, magenta, cyan, and black toners, respectively. The developing unit 34 of each of the image forming units 30Y, 30M, 30C, and 30K uses the yellow, magenta, cyan, and black toners stored in its own toner storage unit 341, and is formed on the photosensitive drum 31. Develop the latent image. As a result, each developing unit 34 forms a toner image of each color of yellow, magenta, cyan, and black on each photoconductive drum 31 and eventually transfers the toner image of each color onto a recording sheet.

  The transfer conveyance unit 40 includes a driven roller 42, a driving roller 43, a transfer belt 41 that is an endless image carrier disposed between the driven roller 42 and the driving roller 43, and four transfer rollers 44. Is provided. Each of the four transfer rollers 44 is provided in the vicinity of the photosensitive drum 31 of each of the image forming units 30Y, 30M, 30C, and 30K, and is provided to face each of the photosensitive drums 31.

  In the transfer conveyance unit 40, the recording paper carried into the most downstream portion of the recording paper conveyance unit 20 by the paper supply unit 10 is conveyed by the recording paper conveyance unit 20, and the transfer conveyance unit 40 from the recording paper conveyance unit 20. In the vicinity of the drive roller 43 in the most upstream part. The transfer conveyance unit 40 conveys the recording paper carried in the vicinity of the driving roller 43 to the vicinity of the driven roller 42 on the downstream side of the transfer conveyance unit 40 by the transfer belt 41. The transfer conveyance unit 40 thus conveys the recording paper and passes the recording paper through the four image forming units 30K, 30C, 30M, and 30Y in this order. The transfer conveyance unit 40 is a fixing unit 50 provided in the vicinity of the driving roller 43 on the recording paper on which toner images are formed from the four image forming units 30K, 30C, 30M, and 30Y. To be brought in.

  The fixing unit 50 heats the recording paper carried in by the transfer conveyance unit 40, whereby the toner images previously transferred to the recording paper by the four image forming units 30K, 30C, 30M, and 30Y are applied to the recording paper. Let it settle.

  The toner storage units 341 of the image forming units 30Y, 30M, and 30C include sensors SY, SM, and SC that detect the remaining amount of toner stored in the toner storage unit 341, respectively. The sensors SY, SM, and SC are examples of the “toner remaining amount detecting means” described in the claims, and yellow, magenta, and magenta stored in the toner storage portion 341 provided in each of the sensors SY, SM, and SC. The remaining amount of cyan toner is detected. The sensors SY, SM, and SC are, for example, a light emitting unit provided at a plurality of height positions on the inner wall of the toner storage unit 341 and an inner wall on the side facing the inner wall to which the light emitting unit is attached. The light emitting unit and the light receiving unit are attached depending on whether the light emitted from the light emitting unit is received by the light receiving unit. By determining whether toner is present up to the position, the toner amount in the toner storage unit 341 is detected. The “toner remaining amount detecting means” in the claims is not limited to the sensors SY, SM, and SC. For example, in the control unit 9 described later, the amount of toner used by each of the image forming units 30Y, 30M, and 30C is changed to the full toner amount, the color toner usage information during printing, the density information of each color, and the dot number information. Or the like, and the toner amount calculation unit may be a “detection unit” in the claims.

  The control unit 9 is an information processing apparatus and controls the operation of each unit of the copying machine 1. Based on the remaining amounts of toner detected by the sensors SY, SM, and SC, the control unit 9 forms an overlay image included in the print target image R2 (FIG. 2) that the image forming units 30Y, 30M, and 30C form on the recording paper. The color component of O3 (FIG. 2) is changed.

  FIG. 2 is a block diagram illustrating a schematic configuration of the control unit 9. The control unit 9 includes a print target image generation unit 91, a hard disk drive 92, and a print control unit 93.

  The print target image generation unit 91 acquires overlay data of the original overlay image O1 from the hard disk drive 92, and applies color conversion processing to the acquired overlay data, thereby adding a part of the print target image to the original image R1. A suitable color overlay image O2 is generated. The print target image generation unit 91 acquires the data of the document image R1 read from the document by the image reading unit 7 from the image reading unit 7. The print target image generation unit 91 generates, on the built-in memory 912, a print target image R2 in which an appropriate color overlay image O2 is superimposed on a part of the original image R1 based on the acquired original image R1 data. To do.

  The hard disk drive 92 may be a simple RAM or a simple ROM as long as it has a storage function described below. The memory 912 can also take a variety of forms as well.

  The print control unit 93 controls the operation of the image forming unit 30 to cause the image forming unit 30 to print the print target image R2 formed on the memory 912 on the recording paper P.

  The hard disk drive 92 is a storage unit in which the original overlay image O1 is stored in advance. The original overlay image O1 is an image showing characters such as “confidential”, “copy”, “confidential”, “extra secret”, and is represented by, for example, a monochrome binary gradation. The original overlay image O1 is an additional image that is printed in addition to the original image R1. Note that images such as ruled lines and form frames, and images such as page numbers and headers / footers may be handled as the original overlay image O1.

  FIG. 3 is a diagram illustrating a configuration of the print target image generation unit 91. The print target image generation unit 91 includes a toner amount ratio storage unit 93m in addition to the memory 912 described above. The toner amount ratio storage unit 93m stores a correspondence relationship between the remaining amount of toner of each color toner and the ratio of each color toner amount used for image formation of the overlay image (appropriate color overlay image O2). The left side of the table in the toner amount ratio storage unit 93m in FIG. 3 shows the remaining amount of toner of each color detected by the sensors SY, SM, and SC (FIG. 1) for detecting the remaining amount of toner for each color. On the right side, the ratios of the toner amounts of yellow, magenta, and cyan used to form an overlay image corresponding to the toner remaining amount are shown. In the table of FIG. 3, combinations of the remaining amount of toner and the ratio of the amount of each color toner used for image formation of the corresponding overlay image are shown by arrows.

  Based on the correspondence stored in the toner amount ratio storage unit 93m, the print target image generation unit 91 determines the remaining toner amount of each color from the remaining toner amounts of yellow, magenta, and cyan detected by the sensors SY, SM, and SC. The ratio of each color toner used for image formation of the overlay image corresponding to the amount is specified, and the ratio of the color of the original overlay image O1 composed of a monochrome binary image is converted by the specified each color toner amount ratio to obtain an appropriate color. An overlay image O2 is generated.

  The correspondence relationship between the remaining amount of toner of each color stored in the toner amount ratio storage unit 93m and the amount of toner of each color used for image formation of an overlay image will be described in detail. For example, the remaining amount of toner is detected by the sensors SY, SM, and SC at eight levels indicated by values of 0 to 7. Level 0 is a level indicating that the remaining amount of toner is minimum, and level 7 is a level indicating that the amount of remaining toner is maximum. The toner amount ratio storage unit 93m stores the remaining amount of toner of each color at the level of 0 to 7. On the other hand, the toner amount of each color used for image formation of the overlay image is also stored in the toner amount ratio storage unit 93m at eight levels (0 level is the minimum level and 7 level is the maximum level). The amount of toner remaining in each color and the value of each color indicated as the level of the amount of each color toner used for image formation of the overlay image are the ratio of the amount of toner remaining for each color and the ratio of the amount of each color toner used for image formation of the overlay image. It shows. Further, as shown in FIG. 3, the correspondence between the ratio of the remaining amount of toner of each color stored in the toner amount ratio storage unit 93m and the ratio of the amount of each color toner used for image formation of the overlay image is as follows. They are set the same.

  FIG. 4 is a flowchart showing print processing by the copying machine 1. In S1, the sensors SY, SM, and SC (FIGS. 1 and 2) detect the remaining amounts of yellow, magenta, and cyan toners stored in the toner storage units 341 of the image forming units 30Y, 30M, and 30C, respectively. To do. In S2, the print target image generation unit 91 reads from the toner amount ratio storage unit 93m the ratio of each color toner amount used for image formation of the overlay image corresponding to the ratio of each color toner remaining amount detected in S1.

  In S3, the print target image generation unit 91 acquires the overlay data of the original overlay image O1 from the hard disk drive 92, and uses the ratio of the amount of each color toner used for image formation of the overlay image read in S2, to use the original overlay image O1. The appropriate color overlay image O2 is generated by converting the ratio of the colors constituting the image.

  In S4, the print target image generation unit 91 expands the appropriate color overlay image O2 generated in S3 in the memory 912. In S <b> 5, the print target image generation unit 91 acquires document image data from the image reading unit 7.

  In S6, the print target image generation unit 91 stores the document image R1 including the document image data acquired in S5 in an area of the memory 912 different from the development area of the appropriate color overlay image O2.

  In S <b> 7, the print target image generation unit 91 specifies a synthesis region in the original image R <b> 1 stored in the memory 912 in S <b> 6 for combining the appropriate color overlay image O <b> 2 and combines the appropriate color overlay image O <b> 2 with the original image R <b> 1. That is, the print target image generation unit 91 specifies the start address of the synthesis area, the size in the main scanning direction, and the size in the sub scanning direction in the memory 912 based on the development area of the appropriate color overlay image O2. The print target image generation unit 91 stores the original image R1 synthesis area in the memory 912, which is specified by the head address, the size in the main scanning direction, and the size in the sub scanning direction, in the memory 912 in S4. The appropriate overlay image O2 is written. Note that the print target image generation unit 91 may perform the writing by so-called DMA (Direct Memory Access). In this way, the print target image generation unit 91 combines the appropriate color overlay image O2 with the document image R1 to generate the print target image R2.

  In S <b> 8, the print control unit 93 causes the image forming unit 30 to print the print target image R <b> 2 on the recording paper P. At this time, the image forming unit 30 generates an appropriate color overlay image O2 using each color toner having a ratio of each color toner amount used for image formation of the overlay image corresponding to the ratio of the remaining amount of each color toner detected in S1. Try to print. The amounts of cyan, magenta, and yellow toners used by the image forming unit 30 to print the appropriate color overlay image O2 included in the print target image R2 are yellow and magenta detected by the sensors SY, SM, and SC in S1. The level of the toner remaining amount for each of the cyan colors is the same. For this reason, the amount of toner used for printing the appropriate color overlay image O3 included in the print target image R2 increases as the remaining amount of toner detected by the sensors SY, SM, and SC increases.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. Hereinafter, a second embodiment of the present invention will be described. FIG. 5 is a diagram illustrating a correspondence relationship between the toner remaining amount of each color toner applied in the second embodiment and the ratio of the amount of each color toner used for image formation of the overlay image. In the second embodiment, among yellow, cyan, and magenta, yellow that is difficult for humans to visually recognize is set as a difficult-to-view color, and the ratio of the amount of each color toner used to generate the appropriate color overlay image O3 is yellow. A ratio whose value is smaller than that of the first embodiment is adopted.

  For example, as shown in FIG. 5 as a toner amount ratio 93mc, the yellow value in the ratio of each color toner amount at the time of printing is made smaller than the value in the remaining toner ratio of each color detected by the sensors SY, SM, and SC. .

  In the example shown in FIG. 5 as a toner amount ratio 93 mb, the ratio of the toner amount of each color at the time of printing is not the same as the toner remaining amount ratio of each color detected by the sensors SY, SM, and SC. By increasing the value of magenta in this ratio, the ratio of the amount of yellow used in each toner amount is reduced. Further, in the example shown as the toner amount ratio 93ma in FIG. 5, the ratio of the amount of yellow used in each color toner amount is increased by increasing the ratio of cyan and magenta to yellow in the ratio of each color toner amount used for image formation of the overlay image. Is made smaller. Note that, in the toner remaining ratio of each color corresponding to the toner amount ratio 93 ma, the remaining toner levels of cyan and magenta are “0”. However, as described above, the “0” is the remaining level of 8 only. It is shown in stages, and the “0” does not only indicate that there is no remaining toner.

  In this way, by reducing the ratio of the amount of yellow used in each color toner amount, the generation of the appropriate color overlay image O2 by the print target image generation unit 91 based on the toner amount ratio storage unit 93m makes it possible to achieve appropriate visibility with good visibility. The color overlay image O2 is reliably generated.

  Next, a third embodiment of the present invention will be described. For example, the print target image generation unit 91 replaces the generation process of the appropriate color overlay image O2 based on the toner amount ratio storage unit 93m with the color having the largest remaining amount of toner detected by the sensors SY, SM, and SC. The appropriate color overlay image O2 may be generated using only the toner. However, only when the color with the largest remaining amount of toner detected by the sensors SY, SM, and SC is not the difficult-to-view yellow color, the print target image generation unit 91 has the largest amount of remaining toner. The processing for generating the appropriate color overlay image O2 may be performed using only the toner.

  In the above embodiment, the image forming apparatus according to the present invention has been described as the copying machine 1. However, the image forming apparatus according to the present invention is not limited to the copying machine, and includes a printer, a facsimile machine, a printer function, a facsimile machine function, and a copy machine. A multifunction machine or the like having a function may be used. For example, when the image forming apparatus according to the present invention is a printer or a facsimile machine, an interface for acquiring print target data from a personal computer or the like connected to the image forming apparatus or receiving fax data from an external line facsimile machine The receiving unit is an example of a print target data acquiring unit in the scope of claims.

1 is a diagram schematically showing an internal configuration of a copying machine according to an embodiment of the present invention. It is a block diagram which shows schematic structure of a control part. It is a figure which shows the structure of a printing object image generation part. 6 is a flowchart showing printing processing by a copying machine. FIG. 9 is a diagram illustrating a correspondence relationship between the remaining amount of toner of each color toner applied in the second embodiment and the ratio of the amount of each color toner used for image formation of an overlay image.

Explanation of symbols

1 Copying machine (image forming device)
7 Image reading unit (printing target data acquisition means)
9 Control unit 30Y Image forming unit (printing means)
30M image forming unit (printing means)
30C image forming unit (printing means)
30K image forming unit (printing means)
30 Image forming unit (printing means)
91 Print target image generation unit (overlay data acquisition means, print target image generation means)
92 Hard disk drive (overlay data acquisition means)
93m toner amount ratio storage unit 93 print control unit SY, SM, SC sensor (toner remaining amount detecting means)

Claims (4)

Print target data acquisition means for acquiring print target data;
Overlay data acquisition means for acquiring overlay data of an overlay image to be superimposed on an image composed of print target data acquired by the print target acquisition means;
A print target image generating unit configured to generate a print target image by combining the print target data acquired by the print target data acquiring unit and the overlay data acquired by the overlay data acquiring unit;
Printing means for printing with toner of a plurality of colors;
Toner remaining amount detecting means for detecting the remaining amount of toner of each color toner of the printing means;
A printing control unit that causes the printing unit to print the printing target image generated by the printing target image generation unit;
The print target image generating means uses the ratio of the toner remaining amount of each color toner detected by the toner remaining amount detecting means as the ratio of the amount of each color toner used for image formation of an overlay image composed of the overlay data An image forming apparatus that generates an image.   The print target image generating means converts a predetermined difficult-to-view color value into a predetermined small value for the ratio of the toner remaining amount of each color toner detected by the toner remaining amount detecting means, The image forming apparatus according to claim 1, wherein the toner remaining amount ratio after conversion is a ratio of the amount of each color toner used for image formation of the overlay image.   The print target image generating means uses the amount of toner of each color used for image formation of the overlay image so that only the color having the largest toner remaining amount detected by the toner remaining amount detection means is used for image formation of the overlay image. The image forming apparatus according to claim 1, wherein the ratio is generated.   The print target image generation unit is configured to display only the color with the largest amount of remaining toner when the color with the largest amount of remaining toner detected by the remaining amount of toner detection unit is not the difficult-to-view color. The image forming apparatus according to claim 3, wherein a ratio of the amount of each color toner used for image formation of the overlay image is generated for use in formation.

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