JP2009086578A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that avoids interruption of service provision due to decrease of toner. <P>SOLUTION: The image forming apparatus includes: an area division means for dividing image data comprising a plurality of pixels into a character area and a non-character area; a residual amount detection means for detecting a residual amount of two or more of toner for every toner; a character color changing means for changing a color pixel to another change color when the residual amount of the predetermined kind of toner is equal to or less a predetermined amount and the toner whose amount is equal to or less the predetermined amount is toner constituting the color pixel of partial image data corresponding to the character area out of the image data; and a printing means for printing the image data after change. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a digital copying machine, a printer, and a scanner, and more particularly to an image forming apparatus that avoids interruption of service provision due to toner reduction.

  An image processing apparatus that supports output of a color image uses a plurality of types of toner, and outputs a color image by changing the combination of the plurality of types of toner according to the color of each pixel constituting the document. ing.

  Since a plurality of types of toners are used in this way, the amount of reduction of each toner varies depending on, for example, the characteristics and number of color images to be output. As a result, only the predetermined toner becomes empty, and the original image may not be expressed. In such a case, the amount of toner is detected in advance, and a warning such as a message prompting replacement (addition) of the toner is output when the remaining amount of toner is low.

Japanese Patent Application Laid-Open No. 2000-356873 (Patent Document 1) uses another alternative toner when the amount of priority color toner decreases (near-end state) or becomes empty (end state). Thus, a technique for continuing the printing process is disclosed.
JP 2000-356873 A

  By the way, the purpose of outputting a color image is to obtain the expressive power of the color image. That is, for the output of a character, the content that the character means is important, but in the color image, the expression by the color is important.

  On the other hand, in the above prior art, when the toner is reduced, all colors of the printed matter are changed to other colors. That is, when the toner is in the end state or near-end state, the color other than characters, for example, the image region (halftone dot region) is changed to an alternative color, that is, a printed matter that is not intended by the user for the image region is output. The output of such printed matter is eventually discarded, resulting in wasteful consumption of toner. In addition, a user who places emphasis on expression in the image area needs to wait for toner replenishment, that is, service provision interruption (downtime) due to toner reduction occurs.

  SUMMARY An advantage of some aspects of the invention is to provide an image forming apparatus capable of obtaining a printed material that maintains a quality acceptable by the user even when the amount of toner is reduced, and that avoids interruption of service provision. For the purpose.

  The present invention employs the following means in order to achieve the above object. That is, in the image forming apparatus according to the present invention, an area dividing unit that divides image data composed of a plurality of pixels into a character area and a non-character area, and a remaining amount of a plurality of types of toner is detected for each toner. The remaining amount detecting means and the toner that has reached the predetermined amount or less of the predetermined amount of toner constitute the colored pixels of the partial image data corresponding to the character area in the image data. In the case of the toner to be used, a character color conversion unit that converts the colored pixel into another change color and a printing unit that prints image data converted by the character color conversion unit are provided.

  In addition, there are a configuration in which the changed color is a color that can be configured with other toners excluding the toner that is less than or equal to a predetermined amount, and a configuration in which the changed color is configured with a mixing ratio that is the same as the remaining amount ratio of each toner.

  The plurality of types of toner may be cyan, magenta, yellow, and black.

  By converting the image data so that the toner with less remaining amount is not used only for the character area, the color area of the original image is maintained even when using the toner with less remaining amount for the non-character area. Keeps only the meaning of the characters, ignoring the color representation. As a result, even when the predetermined toner is reduced, it is possible to output a printed matter that maintains a quality acceptable by the user, that is, it is possible to avoid interruption of service provision due to toner reduction.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: It is not the thing of the character which limits the technical scope of this invention.

  The image forming apparatus according to the present invention will be described below.

  FIG. 1 is a schematic diagram of the image forming apparatus 100. However, details of each part not directly related to the present invention are omitted.

  The image forming apparatus 100 according to the present invention corresponds to, for example, a printer, a single scanner, or a multifunction machine including a printer, a copy, a scanner, a fax machine, and the like.

  As an example, the operation of the image forming apparatus when copying a document using a multifunction machine will be briefly described.

  For example, when a user prints a document using the multifunction device, the document is placed on the document table 103 or the table 105 shown in FIG. 1, and a print instruction is given to the operation panel provided near the document table. Do. When the instruction is given, printing is performed by operating the following units (drive units).

  That is, as shown in FIG. 1, the image forming apparatus 100 according to the present embodiment includes a main body 101 and a platen cover 102 attached above the main body 101. A document table 103 is provided on the upper surface of the main body 101, and the document table 103 is opened and closed by a platen cover 102. The platen cover 102 is provided with an automatic document feeder 104, a placing table 105, and a sheet discharging table 109.

  The automatic document feeder 104 includes a document conveyance path 108 formed inside the platen cover 102, a pickup roller 106 and a conveyance roller 107 provided inside the platen cover 102, and the like. The document conveyance path 108 is a document conveyance path that leads from the placement table 105 to the sheet discharge table 109 via a reading position P where reading is performed by the reading unit 110 provided in the main body 101.

  The automatic document feeder 104 pulls out each document placed on the placing table 105 to the inside of the transport path 108 by the pickup roller 106 and passes the document pulled out by the transport roller 107 and the like through the reading position P. The paper is discharged onto the paper base 109. When the document passes the reading position P, the document is read by the reading unit 110.

  The reading unit 110 is provided below the document table 103, and its details are shown in FIG. The reading unit 110 includes a first light source 111 that illuminates the document table 103 in the main scanning direction, a slit 116 that selectively passes light from the document table, and a mirror 112 that guides light from the document table. The movable carriage 117, the second movable carriage 118 including mirrors 113A and 113B that reflect the reflected light from the first movable carriage 117 again, and the lens group 119 that optically corrects the light guided by the mirror, An image sensor 115 that receives the light corrected by the lens group 119, and an image data generation unit 114 that converts the light received by the image sensor into an electrical signal and performs correction / correction as necessary. .

  When reading a document on the automatic document feeder 104, the light source 111 moves to a position where the reading position P can be irradiated and emits light. Light from the light source 111 is reflected by a document that passes through the document table 103 and passes through the reading position P, and is guided to the image sensor 115 by the slit 116, mirrors 112, 113A, and 113B, and the lens group 119. The image sensor 115 converts the received light into an electrical signal and transmits it to the image data generation unit 114. The light received by the image sensor 115 is input to the image data generator 114 as analog electrical signals of R (red), G (green), and B (blue), where analog-to-digital conversion is performed. Digitized. Further, the image data generation unit 114 uses the sequentially converted digital signal as unit data, and corrects and corrects the unit data as necessary to generate image data including a plurality of unit data. Store in the storage unit 114B.

  The reading unit 110 can read not only the document conveyed by the automatic document feeder 104 but also the document placed on the document table 103. When reading a document placed on the document table 103, the first carriage 112 moves in the sub-scanning direction while emitting light from the light source 111, so that the optical path length from the light source 111 to the image sensor 115 is constant. The second moving carriage 118 moves in the direction of the image sensor 115 at a half speed of the first moving carriage 117.

  The image sensor 115 electrically outputs light from the document placed on the document table 103 based on the light guided to the mirrors 112, 113 </ b> A, 113 </ b> B, as in the case of the document conveyed to the automatic document feeder 104. The signal is converted into a signal, and based on this, the image data generation unit 114 generates image data and stores it in the first storage unit 114B. In addition, each part which comprises the said reading part 110 operate | moves as a reading means 401 mentioned later by performing a series of processes.

  A printing unit 120 that prints image data is provided below the reading unit 110 of the main body 101. The image data that can be printed by the printing unit 120 is generated by the image data generation unit 114 as described above, or from other terminals such as a personal computer connected to the image forming apparatus 100 and a network such as a LAN. Is received via.

  As a printing method performed by the printing unit 120, an electrophotographic method is used. That is, the photosensitive drum 121 is uniformly charged by the charger 122, and then the photosensitive drum 121 is irradiated by the laser 123 to form a latent image on the photosensitive drum 121, and toner is attached to the latent image by the developing device 124. In this method, a visual image is formed and the visible image is transferred onto a sheet by a transfer roller.

  Note that in the image forming apparatus corresponding to the full-color image, the developing device (rotary developing device) 124 is rotated in the circumferential direction around a rotation axis configured in a direction perpendicular to the paper surface of FIG. A developing unit in which color toner is stored is disposed at a position facing the photosensitive drum 121. In this state, the latent image on the photosensitive drum 121 is developed with toner stored in the developing device 124 and transferred to the intermediate transfer belt 125A. The developing device 124 includes four developing units 124 (Y), (C), (M), and yellow (Y), cyan (C), magenta (M), and black (K). (K). By repeating the transfer to the intermediate transfer belt 125A for each color, a full color image is formed on the intermediate transfer belt 125A.

  The print medium on which the visible image is printed, that is, the paper, is placed on a paper feed tray such as the manual feed tray 131 and the paper feed cassettes 132, 133, and 134.

  When the printing unit 120 performs printing, one sheet of paper is pulled out from any one of the paper feed trays by using the pickup roller 135, and the pulled-out paper is transported by the transport roller 137 (if the manual tray 131 is used) Roller 136) or registration roller 138 feeds between intermediate transfer belt 125A and transfer roller 125B.

  When the visible image on the intermediate transfer belt 125 is transferred onto the sheet fed between the intermediate transfer belt 125 and the transfer roller 125, the printing unit 120 uses the conveying belt 126 to fix the visible image. Send paper to 127. The fixing device 127 includes a heating roller 128 with a built-in heater and a pressure roller 129 pressed against the heating roller 128 with a predetermined pressure. When the sheet passes between the heating roller 128 and the pressure roller 129, the visible image is fixed to the sheet by heat and the pressing force to the sheet. The printing unit 120 discharges the sheet that has passed through the fixing device 127 to the discharge tray 130.

  The basic copy service processing in the image forming apparatus 100 has been described above.

  In the image forming apparatus 100, as shown in the schematic configuration diagram of FIG. 3, a central processing unit (CPU) 301, a random access memory (RAM) 302, a read only memory (ROM) 303, and a hard disk drive (HDD). 304 and a driver 305 corresponding to each drive unit in the printing process are connected via an internal bus 306. The CPU 301 uses, for example, the RAM 302 as a work area, executes a program stored in the ROM 303, the HDD 304, and the like, and exchanges data and commands with the driver 305 based on the execution result, thereby performing the above-described FIG. 2 controls the operation of each driving unit 307 shown in FIG.

  Next, details of the printing process of the image forming apparatus according to the present invention will be described with reference to FIGS.

  The procedure in which image data is generated from the original by the image data generation unit 401 (image data generation unit 114 in FIG. 2) and stored in the first storage unit 402 (first storage unit 114B in FIG. 2) is as described above. It is.

  In such a state, during the printing process, the remaining amount detection means 404 is always or appropriately provided with a plurality of types of toner tanks 406 (yellow toner tank 406Y, cyan toner tank 406C, magenta toner tank). The remaining amount of toner in each of the types (colors) is detected and transmitted to the character color conversion means 405.

  The character color conversion unit 405 appropriately compares each remaining toner amount with a threshold value provided for each toner to determine whether the remaining toner amount is equal to or greater than the threshold value (FIG. 5: S501).

  If it is determined that the remaining amount of all toners is sufficient (greater than the threshold value), the image data stored in the first storage unit 402 is printed by the printing unit 407 (printing unit 120 in FIG. 1). (FIG. 5: S501 No → S503 → END).

  On the other hand, when it is determined that the remaining amount of at least one toner (hereinafter referred to as toner A) is less than a predetermined amount, the image data stored in the first storage unit 402 is divided into regions. The area is divided into a character area and a non-character area by the means 403 (FIG. 5: S502). Various methods are known for the region division. For example, a method of smoothing halftone dots with an integration filter and then separating by lifting an edge portion with a differential filter may be used. Further, the image data is divided into a plurality of sub-blocks, and the difference between the maximum density and the minimum density in the sub-block is obtained, so that the non-character area 603 (halftone area or image area) and other areas (characters) It may be separated into an area 602 and a blank area. In the area dividing process by the area dividing unit 403, the image data is divided into a character area 602 and a non-character area 603, and the area information 601 is transmitted to the character color converting unit 405.

  Subsequently, when the character color conversion means 405 receives the region information 601 and the image data, the character color conversion unit 405 corresponds to the character region 602 in the image data, and among the partial image data composed of a plurality of pixels, It is determined whether the color requires the toner A (FIG. 5: S504). “Whether or not to request toner A” means whether or not toner A is necessary when the colored pixels are embodied on the paper.

  Here, when the toner A is not requested, the image data is printed by the printing unit 407 (FIG. 5: S504 No → S503 → END).

  On the other hand, when it is determined that the color pixel constituting the character area requires the toner A, the character color conversion unit 405 converts the color component constituting the color pixel into a color component (excluding the toner A element) ( Change color). For example, assuming that yellow (Y) is toner A, the Y component of all the color components (Y, C, M, K) constituting the character area is converted to “0 (none)” (FIG. 5: S505). Then, the converted image data is transmitted to the printing unit 407 and printed by the above-described procedure (FIG. 5: S506).

  As described above, by converting the image data so as not to use the toner with a small remaining amount only for the character region, the non-character region can be expressed by the color of the original image even using the toner with a small remaining amount. The character area retains only the meaning of the character, ignoring the color expression. As a result, even when the predetermined toner is reduced, it is possible to output a printed matter that maintains a quality acceptable by the user, that is, it is possible to avoid interruption of service provision due to toner reduction.

  In the above description, the Y component is set to “0”, that is, it is converted into a color that can be composed of other toners except the toner A, but is not limited thereto. That is, for example, the changed color may be configured with the same mixing ratio as the remaining amount ratio acquired by the remaining amount detecting unit 404. For example, a black system is usually used as the color constituting the character area. Therefore, when black corresponds to the toner A and the remaining amount ratio is Y: M: C: K = 5: 7: 6: 1, the element of the character region (Y: M: C: K) = (0: 0: 0: 10) is converted to (5: 7: 6: 0). As a result, it is possible to output characters in black color based on subtractive color mixing, and it is possible to suppress consumption of toner with a small remaining amount. When the remaining amount ratio is Y: M: C = 5: 7: 1, the character area element (Y: M: C) is converted into a ratio of (5: 7: 1). This also makes it possible to suppress consumption of toner with a small remaining amount.

  The image forming apparatus according to the present invention can output a printed material maintaining a quality acceptable by the user even when the predetermined toner is reduced, that is, an image in which service provision interruption due to toner reduction is avoided. Useful as a forming device.

1 is a schematic diagram of an image forming apparatus according to the present invention. The enlarged view of a reading part. 1 is a schematic configuration diagram of an image forming apparatus according to the present invention. 1 is a schematic functional block diagram of an image forming apparatus according to the present invention. The flowchart which shows the process sequence which concerns on this invention. The figure explaining the structure of area | region information.

Explanation of symbols

401 Image data generating means 402 First storage means 403 Area dividing means 404 Remaining amount detecting means 405 Character color converting means 406Y Yellow toner tank (Y)
406C Cyan Toner Tank (C)
406M Magenta toner tank (M)
406K Black Toner Tank (K)
407 printing means

Claims (4)

Area dividing means for dividing image data composed of a plurality of pixels into character areas and non-character areas;
A remaining amount detecting means for detecting a remaining amount of a plurality of types of toner for each toner;
When the remaining amount of the predetermined type of toner is equal to or less than a predetermined amount, and the toner that is equal to or less than the predetermined amount is the toner constituting the colored pixel of the partial image data corresponding to the character area in the image data, A character color conversion means for converting the colored pixel into another change color;
Printing means for printing the image data after being converted by the character color conversion means;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the changed color is a color that can be constituted by other toners excluding the toner that is equal to or less than the predetermined amount.   The image forming apparatus according to claim 1, wherein the change color is a color having a mixing ratio that is the same as a remaining amount ratio of the toners.   The image forming apparatus according to claim 1, wherein the plurality of types of toner are cyan, magenta, yellow, and black.

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