JP2007178489A - Image forming apparatus, image forming method, image adjusting method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of keeping the consistency of basic image quality. <P>SOLUTION: In the image forming apparatus 10, first, the difference between printing results by the former apparatus and printing results by the replaced image forming apparatus 10 is received. Next, the exposure amount and parameters of a developing unit are adjusted based on the difference, then positive letter/line image quality as basic image quality is adjusted. Thereafter, negative letter/line image quality is adjusted by image processings, based on the difference. Further, as necessary, gradation correction data and color conversion data are adjusted. When an input image is received by the image forming apparatus 10, the image is plotted under the adjusted image processing, and the color conversion and the gradation correction are performed, by using the adjusted color conversion data and the adjusted gradation correction data, and then the image is formed on a sheet by the adjusted image forming processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer, a facsimile machine, and a copying machine.

  In many cases, a plurality of image forming apparatuses are connected to a network. Among the plurality of image forming apparatuses, the difference and variation in the basic image quality of the image forming apparatuses is a big problem.

Patent Document 1 discloses a technique for reducing image quality degradation by judging the structure of an object in a page description language and overdefining definition operations for characters and line drawings in a color background that deteriorate due to marking engine characteristics. ing.
Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique of printing an image quality adjustment pattern and reading and controlling an image on a photoconductor with a CCD in order to control subtle changes in line width.
Patent Document 3 discloses a method of reading an image on a photoconductor with a light amount sensor and controlling it with a pulse width modulation unit in order to adjust the machine difference and the line width over time.

  However, in any of these methods, the character / line image quality greatly depends on the technology used in the marking engine and differs depending on the printers and printing apparatuses of each company. When new products and printers are introduced for speeding up, high image quality, and low cost, the difference in image quality between the predecessor and the attached printer may be more important than improving the image quality of one printer. is there. In this case, the challenge is to maintain consistency in document quality between the old and new printers and the attached printer in the workflow.

JP 2000-137794 A Japanese Patent Laid-Open No. 2004-341055 JP 2003-287931 A

  The present invention has been made from the above-described background, and an object thereof is to provide an image forming apparatus capable of maintaining the consistency of the basic image quality.

  In order to achieve the above object, an image forming apparatus according to the present invention includes at least one device that forms an image, a generation unit that selectively generates a positive image and a negative image with respect to an input image, and the generation A first adjusting unit that adjusts the output of the device with respect to one of a positive image and a negative image by the unit; and a second adjusting unit that adjusts the other of the positive image and the negative image by the generating unit by image processing. 2 adjustment means.

Preferably, the device includes an exposure apparatus, and the first adjustment unit adjusts an exposure amount of the exposure apparatus.
Preferably, the device includes a developing device, and the first adjusting unit adjusts a parameter of the developing device.

Preferably, the second adjusting means adjusts the thickness of a line included in the image.
Preferably, the second adjusting means adjusts an edge region included in the image.

Preferably, based on the color conversion data adjusted by the color conversion adjustment means, the color conversion data adjustment means for adjusting the color conversion data based on the adjustment results by the first adjustment means and the second adjustment means. And color conversion means for color-converting the image.
Preferably, gradation correction data adjustment means for adjusting gradation correction data based on the adjustment results by the first adjustment means and the second adjustment means, and the level adjusted by the gradation correction data adjustment means. The image processing apparatus further includes gradation correction means for correcting the gradation of the image based on the tone correction data.

Preferably, the image processing apparatus further includes a difference extraction unit that extracts a difference between a plurality of output images output based on one image data, and the first adjustment unit is based on the difference extracted by the difference extraction unit. To adjust the output of the device.
Preferably, the image processing apparatus further includes a difference receiving unit that receives a difference between a plurality of output images output based on one image data, and the first adjustment unit is based on the difference received by the difference receiving unit. Adjust the output of the device.

  In the image forming method according to the present invention, in an image forming apparatus having at least one device for forming an image, a positive image and a negative image are selectively generated with respect to an input image, and the generated positive image and negative image are generated. The output of the device is adjusted for one of the images, and the other of the generated positive image and negative image is adjusted by image processing.

  Further, the image adjustment method according to the present invention adjusts the device output in the image forming apparatus so as to match one of a positive image and a negative image output from another image forming apparatus, Corresponding to one of the negative images, the positive image and the other of the negative images are adjusted by image processing.

  Also, a first program according to the present invention is a generation step of selectively generating a positive image and a negative image with respect to an input image in an image forming apparatus having a computer and at least one device for forming an image. A first adjustment step of adjusting the output of the device with respect to one of the generated positive image and negative image; and image processing of the other of the generated positive image and negative image And causing the computer of the image forming apparatus to execute a second adjustment step to be adjusted.

  Further, the second program according to the present invention adjusts the device output in the image forming apparatus so as to match one of the positive image and the negative image output from the other image forming apparatus in the image forming apparatus including the computer. The first adjustment step and the second adjustment step of adjusting the other of the positive image and the negative image by image processing corresponding to one of the positive image and the negative image in the image forming apparatus are performed by the image forming apparatus. Let the computer run.

  The image forming apparatus according to the present invention can maintain the consistency of basic image quality.

First, the background and outline of the present invention will be described in order to facilitate understanding of the present invention.
FIG. 1 shows an image forming system 1 including an image forming apparatus 10 according to an embodiment of the present invention. As shown in FIG. 1, the image forming system 1 includes a plurality of image forming apparatuses 10-1 and 10-2 connected via a network 3 and a terminal device 2 such as a personal computer (PC).
In the case where any one of a plurality of components such as the image forming apparatuses 10-1 and 10-2 is indicated without being specified, the image forming apparatus 10 or the like may be simply abbreviated.

The terminal device 2 displays an image on a CRT display device or a liquid crystal display device, and transmits the image data to the image forming device 10 to request printing. The terminal device 2 may be a terminal other than a PC having a control device such as an MCU (Micro Controller Unit), an input / output device such as a touch panel, and a communication device that transmits and receives signals via the network 3.
The network 3 may be wired or wireless. A plurality of terminal devices 2 may be connected to the network 3.

The user replaces or adds an image forming apparatus for reasons of machine life, productivity improvement, and improvement of image quality such as photographs.
FIG. 2 is a diagram for explaining replacement of the plurality of image forming apparatuses 10-1 and 10-2 connected via the network 3. The image forming apparatuses 10-1 and 10-2 are a printer and a multifunction machine manufactured by A company, respectively.
As shown in FIG. 2, the image forming apparatus 10-1 is replaced with an image forming apparatus 10-3 (for example, a printer) manufactured by B company, and the image forming apparatus 10-2 is also an image forming apparatus 10-4 manufactured by B company. (For example, a multifunction device).

  In this case, the basic image quality is obtained when the technologies adopted for the engine and the controller in the image forming apparatuses before and after replacement (for example, the image forming apparatus 10-1 and the image forming apparatus 10-3) differ regardless of the manufacturer. Positive characters and line image quality will be different. For example, in an engine, the line reproduction performance varies depending on the wavelength of the laser exposure device, the beam diameter and light amount, the sensitivity of the photosensitive member, the developing method, the toner diameter and shape, the transfer method, the fixing method, and the like. In the controller, the character and line drawing quality differ depending on the drawing resolution, font shape, weight parameters, and the like.

FIG. 3 is a diagram illustrating the difference in image quality in the image forming apparatus before and after replacement. FIG. 3A illustrates an image printed by the image forming apparatus before replacement, and FIG. An example of an image printed by the replaced image forming apparatus is illustrated.
As illustrated in FIG. 3A, this image includes areas C and D including positive characters / line drawings, regions E and F including negative characters / line drawings, and gradation and color adjustment for calibration. Region G is included. For example, positive characters / line drawings included in the regions C ′ and D ′ illustrated in FIG. 3B have different line thicknesses from those included in the regions C and D in FIG.

  This basic image quality adjustment must be performed. However, when positive character / line drawing adjustment, which is the basic image quality by the engine, is performed, the current situation of dot gain or dotless occurs, and as a secondary obstacle, the quality of the negative character / line drawing and the change in gradation and color reproduction are changed. It will occur. For example, the image quality changes in the negative image areas E ′ and F ′ and the area G ′ illustrated in FIG.

FIG. 4 is a diagram for explaining an image quality adjustment method in the image forming apparatus 10 according to the present invention.
As shown in FIG. 4, when the image forming apparatuses 10-1 and 10-2 that are the preceding machines are replaced with the image forming apparatuses 10-3 and 10-4, the image forming apparatuses 10-1 and 10-that are the preceding machines. 2 is compared with the print result (print 1) of the original (target chart) by 2 and the print results (print 2) of the original by the image forming apparatuses 10-3 and 10-4. More specifically, these printing results are read by a scanner provided in the image forming apparatus 10 or a scanner connected via a network, and a difference between the print 1 and the print 2 is extracted. Based on the extracted difference, the target value is set in the image forming apparatuses 10-3 and 10-4 and used for image quality adjustment.
The difference may be extracted by visual comparison or the like. In this case, the user inputs the difference or target value to the image forming apparatuses 10-3 and 10-4.

  After the adjustment, the image forming apparatuses 10-3 and 10-4 output the same print result (print 1) as the image forming apparatuses 10-1 and 10-2 that are the predecessors. More specifically, when the positive character / line image on the print 2 is narrower than that on the print 1, the image forming apparatuses 10-3 and 10-4 increase and adjust the light quantity of the exposure unit of the marking engine. Conversely, when the positive character / line drawing on the print 2 is thick, the image forming apparatuses 10-3 and 10-4 reduce the amount of light. When further adjustment is required, the image forming apparatuses 10-3 and 10-4 change and adjust the parameters (development bias, applied electric energy, and frequency) of the developing device.

  If there is a difference in image quality before and after replacement despite the adjustment by the marking engine, the image forming apparatuses 10-3 and 10-4 perform adjustment by image processing. More specifically, the image forming apparatuses 10-3 and 10-4 perform negative character / line drawing adjustment by image processing, and perform gradation and color adjustment.

FIG. 5 is a diagram showing a configuration of the tandem type image forming apparatus 10 according to the present invention.
As shown in FIG. 5, the image forming apparatus 10 includes an image reading unit 12, an image forming unit 14, an intermediate transfer belt 16, a paper tray 17, a paper conveyance path 18, a fixing device 19, an image processing device 20, and an image formation control device. 21, an image detection sensor 22 and a user interface (UI) device 23. The image forming apparatus 10 has a function as a full-color copying machine using the image reading unit 12 and a function as a facsimile in addition to a printer function for printing image data received from a personal computer (not shown). It may be a multifunction machine.

  First, the outline of the image forming apparatus 10 will be described. In the upper part of the image forming apparatus 10, an image reading unit 12, an image processing apparatus 20, and an image forming control apparatus 21 are arranged. The image reading unit 12 reads an image displayed on the document 30 and outputs it to the image processing apparatus 20. The image processing apparatus 20 performs color conversion processing and correction processing described later on image data input from the image reading unit 12 or image data input from a personal computer or the like via a network line such as a LAN. Image processing is performed and output to the image formation control device 21. The image forming control device 21 controls the image forming unit 14 based on the image data subjected to image processing. Note that the image formation control device 21 may be included in the image processing device 20 as a part of the image processing device 20.

  A UI device 23 such as a touch panel is provided on the upper surface of the image forming apparatus 10. The UI device 23 displays control information and instruction information of the image forming apparatus 10 and accepts input by the user such as instruction information. That is, the user can operate the image forming apparatus 10 via the UI device 23. Note that the UI device 23 may accept only an input such as a switch, may perform only an output such as a display, or may be a combination of these.

  Below the image reading unit 12, a plurality of image forming units 14 are arranged corresponding to the colors constituting the color image. In this example, the first image forming unit 14K, the second image forming unit 14Y, and the third image forming corresponding to each color of black (K), yellow (Y), magenta (M), and cyan (C). The unit 14M and the fourth image forming unit 14C are arranged horizontally along the intermediate transfer belt 16 with a certain interval. The intermediate transfer belt 16 rotates as an intermediate transfer member in the direction of an arrow A in the figure, and these four image forming units 14K, 14Y, 14M, and 14C are configured based on the image data input from the image processing apparatus 20. The toner images are sequentially formed and transferred (primary transfer) to the intermediate transfer belt 16 at a timing at which the plurality of toner images are superimposed on each other. The order of the colors of the image forming units 14K, 14Y, 14M, and 14C is not limited to the order of black (K), yellow (Y), magenta (M), and cyan (C). ), Magenta (M), cyan (C), black (K), and the like.

  The sheet conveyance path 18 is disposed below the intermediate transfer belt 16. The recording paper 32 supplied from the paper tray 17 is transported on the paper transport path 18, and the toner images of each color transferred onto the intermediate transfer belt 16 are collectively transferred (secondary transfer). The transferred toner image is fixed by the fixing device 19 and discharged to the outside along the arrow B.

Next, each configuration of the image forming apparatus 10 will be described in detail.
As shown in FIG. 5, the image reading unit 12 includes a platen glass 124 on which the document 30 is placed, a platen cover 122 that presses the document 30 onto the platen glass 124, and a document 30 placed on the platen glass 124. And an image reading unit 130 for reading an image. The image reading unit 130 illuminates the original 30 placed on the platen glass 124 with a light source 132, and displays a reflected light image from the original 30 as a full rate mirror 134, a first half rate mirror 135, and a second half half. Scanning exposure is performed on an image reading element 138 made of a CCD or the like through a reduction optical system including a rate mirror 136 and an imaging lens 137, and the color material reflected light image of the document 30 is transferred to predetermined dots by the image reading element 138. It is configured to read by density.

  The image processing device 20 performs predetermined image processing such as color conversion on image data read by the image reading unit 12 or image data input via a network line. The color material reflected light image of the document 30 read by the image reading unit 12 is, for example, document reflectance data of three colors of red (R), green (G), and blue (B). By the image processing by 20, the original color material gradation data of four colors of yellow (Y), magenta (M), cyan (C), and black (K) is converted.

  The image formation control device 21 generates a pulse signal according to the image data (YMCK) input from the image processing device 20 and outputs the pulse signal to the optical scanning device 140. More specifically, the image formation control device 21 performs a first optical scanning device 140K, a second optical scanning device 140Y, a third optical scanning device 140M, and a fourth optical scanning, which will be described later, based on the image data. A pulse signal is output to the device 140C to form an image.

The first image forming unit 14K, the second image forming unit 14Y, the third image forming unit 14M, and the fourth image forming unit 14C are arranged and formed in parallel at a certain interval in the horizontal direction. The configuration is almost the same except that the color of the image is different. Accordingly, the first image forming unit 14K will be described below. The configuration of each image forming unit 14 is distinguished by adding K, Y, M, or C.
The image forming unit 14K forms an electrostatic latent image by an optical scanning device 140K that scans a laser beam in accordance with image data input from the image processing device 20, and a laser beam scanned by the optical scanning device 140K. And an image forming apparatus 150K. Here, the exposure amount of the laser beam is an exposure amount after an adjustment process described later is performed.

  The optical scanning device 140K modulates the semiconductor laser 142K according to the black (K) image data, and emits the laser light LB (K) from the semiconductor laser 142K according to the image data. The laser beam LB (K) emitted from the semiconductor laser 142K is applied to the rotary polygon mirror 146K via the first reflection mirror 143K and the second reflection mirror 144K, and is deflected and scanned by the rotation polygon mirror 146K. The light is irradiated onto the photosensitive drum 152K of the image forming apparatus 150K through the second reflecting mirror 144K, the third reflecting mirror 148K, and the fourth reflecting mirror 149K.

The image forming apparatus 150K includes a photosensitive drum 152K as an image carrier that rotates at a predetermined rotational speed in the direction of arrow A, and primary charging as a charging unit that uniformly charges the surface of the photosensitive drum 152K. And a developing device 156K for developing the electrostatic latent image formed on the photosensitive drum 152K, and a cleaning device 158K. The photosensitive drum 152K is uniformly charged by the scorotron 154K, and an electrostatic latent image is formed by the laser beam LB (K) irradiated by the optical scanning device 140K. The electrostatic latent image formed on the photosensitive drum 152K is developed with black (K) toner by the developing device 156K and transferred to the intermediate transfer belt 16. Residual toner, paper dust, and the like adhering to the photosensitive drum 152K after the toner image transfer process are removed by the cleaning device 158K. Here, the developing device 156K operates based on the adjusted parameters (developing bias, applied electric energy, and frequency).
The other image forming units 14Y, 14M, and 14C also form yellow (Y), magenta (M), and cyan (C) toner images in the same manner as described above, and intermediately transfer the formed toner images of the respective colors. Transfer to belt 16.

  The intermediate transfer belt 16 has a constant tension between the drive roll 164, the first idle roll 165, the steering roll 166, the second idle roll 167, the backup roll 168, and the third idle roll 169. The drive roll 164 is rotationally driven by a drive motor (not shown), and is circulated at a predetermined speed in the direction of arrow A. The intermediate transfer belt 16 is formed into an endless belt shape by, for example, forming a flexible synthetic resin film such as polyimide in a band shape and connecting both ends of the synthetic resin film formed in the band shape by welding or the like. It has been done.

  Further, the intermediate transfer belt 16 includes a first primary transfer roll 162K, a second primary transfer roll 162Y, a third primary transfer roll 162M, and a position facing the image forming units 14K, 14Y, 14M, and 14C, respectively. A fourth primary transfer roll 162C is provided, and the toner images of the respective colors formed on the photosensitive drums 152K, 152Y, 152M, and 152C are transferred onto the intermediate transfer belt 16 in a multiple manner by these primary transfer rolls 162. The The residual toner adhering to the intermediate transfer belt 16 is removed by a cleaning blade or brush of a belt cleaning device 189 provided downstream of the secondary transfer position.

In the paper transport path 18, a paper feed roller 180 for taking out the recording paper 32 from the paper tray 17, a first roller pair 181, a second roller pair 182 and a third roller pair 183 for paper transport, and a recording paper A registration roll 184 is provided that conveys 32 to the secondary transfer position at a predetermined timing.
In addition, a secondary transfer roll 185 that is in pressure contact with the backup roll 168 is disposed at the secondary transfer position on the paper transport path 18, and each color toner image transferred onto the intermediate transfer belt 16 is Secondary transfer is performed on the recording paper 32 by the pressing force and electrostatic force of the secondary transfer roll 185. The recording paper 32 onto which the toner image of each color is transferred is conveyed to the fixing device 19 by the first conveyance belt 186 and the second conveyance belt 187.
The fixing device 19 melts and fixes the toner to the recording paper 32 by performing heat treatment and pressure treatment on the recording paper 32 to which the toner images of the respective colors are transferred.

  An image detection sensor 22 is provided in the paper transport path 18. The image detection sensor 22 reads an image from the recording paper 32 conveyed along the paper conveyance path 18 and measures the feature amount of the image. The feature quantity measured by the image detection sensor 22 is color data such as the density, saturation, hue, and color distribution of each color, for example. The image detection sensor 22 outputs data relating to the read image (read image) to the image processing device 20.

FIG. 6 is a block diagram showing functional configurations of the image processing apparatus 20 and the image formation control apparatus 21. As shown in FIG.
As shown in FIG. 6, the image processing apparatus 20 includes an image drawing unit 200, a color conversion unit 202, a gradation correction unit 204, a positive image output unit 206, a negative image output unit 208, a color conversion data storage unit 210, a gradation The image forming control device 21 includes a device adjustment unit 220. The image formation control device 21 includes a correction data storage unit 212, a color conversion data adjustment unit 214, a gradation correction data adjustment unit 216, and a difference reception unit 218.
Each of the above components included in the image processing device 20 and the image formation control device 21 may be realized in software by a CPU, a memory, a program, or the like, or may be realized in hardware by an ASIC or the like. Further, the image processing apparatus 20 may be included not only in the image forming apparatus 10 but also in a personal computer, for example.

  In the image processing device 20, the image drawing unit 200 receives input image data in a page description language (PDL) format generated by the driver of the terminal device 2 and draws an image based on the PDL of this image. At this time, the image drawing unit 200 adjusts the line thickness of the image element (character, graphic, etc.) included in the image. More specifically, the image drawing unit 200 adjusts the font weight and line width, that is, the width value of the stroke portion describing the line in the language and the width value of the fill for drawing the rectangle, thereby Change the width.

  The positive image output unit 206 generates raster data (color component image) of each color component of the image based on the PDL and outputs a positive image. The negative image output unit 208 outputs a negative image in the same manner. The positive image output unit 206 and the negative image output unit 208 selectively generate a positive image and a negative image with respect to the input image to constitute a generation unit.

Further, the image drawing unit 200 adjusts an edge region included in the image. More specifically, in the case of a negative character / line drawing rasterized in advance, such as image data optically read by the image reading unit 12 or the like, the image drawing unit 200 performs edge extraction processing to obtain an edge portion image. The line width is adjusted by expanding or contracting the region.
Note that the image drawing unit 200 may be provided as pre-processing or post-processing of a color conversion unit 202 and a gradation correction unit 204 described later.

  In this way, the image drawing unit 200 displays the other image of the positive image and the negative image in response to the device adjustment for one of the positive image and the negative image performed by the device adjustment unit 220 described later. A second adjusting means for adjusting by processing is configured. For example, the image drawing unit 200 adjusts the line width of the negative image.

The color conversion unit 202 uses the three-dimensional color conversion table (three-dimensional LUT; LookUp Table) stored in the color conversion data storage unit 210 to convert the RGB color space image input from the image drawing unit 200 into The image data is converted into image data of a color system CMYK color space suitable for printing processing, and output to the gradation correction unit 204.
The color conversion data storage unit 210 stores a three-dimensional LUT indicating the correspondence between the RGB color space data and the CMYK color space data. This three-dimensional LUT is adjusted by a color conversion data adjustment unit 214 described later, and is referred to by the color conversion unit 202.

The gradation correction unit 204 uses the one-dimensional gradation correction table (one-dimensional LUT) stored in the gradation correction data storage unit 212 to input the primary colors of CMYK input from the color conversion unit 202. The gradation is corrected and output to the image formation control device 21.
The gradation correction data storage unit 212 stores a one-dimensional LUT for correcting the gradation of each color of CMYK. This one-dimensional LUT is adjusted by a gradation correction data adjustment unit 216 described later, and is referred to by the gradation correction unit 204.

  The difference receiving unit 218 receives the difference between the printing result by the predecessor and the printing result by the replaced image forming apparatus 10 input by the user via the UI device 23 or the like, and the image drawing unit 200, color conversion The data is output to the data adjustment unit 214, the gradation correction data adjustment unit 216, and the device adjustment unit 220 of the image formation control device 21. The difference receiving unit 218 may receive a difference transmitted from the terminal device 2 via the network 3. Further, the difference receiving unit 218 may receive image data obtained by reading these print results by the image reading unit 12 or the like, and compare these images to extract a difference.

  The color conversion data adjustment unit 214 adjusts the color conversion data based on the adjustment results by the device adjustment unit 220 and the image drawing unit 200. More specifically, the color conversion data adjustment unit 214 has been adjusted by the device adjustment unit 220 and the image drawing unit 200 and then needs to be calibrated for color reproduction (for example, the maximum density has changed). The color correction table parameter value in the three-dimensional LUT stored in the color conversion data storage unit 210 is changed based on the difference input from the difference receiving unit 218.

The gradation correction data adjustment unit 216 adjusts the gradation correction data based on the adjustment results from the device adjustment unit 220 and the image drawing unit 200. More specifically, the gradation correction data adjustment unit 216 makes adjustments for gradation reproduction after adjustment by the device adjustment unit 220 or the like (for example, gradation reproduction in a halftone area). Only the change), the one-dimensional LUT stored in the gradation correction data storage unit 212 is adjusted based on the difference input from the difference receiving unit 218.
In particular, when the difference is large, the color conversion data adjustment unit 214 adjusts the color conversion data, and when the difference is small, the gradation correction data adjustment unit 216 adjusts the gradation correction data.

The image formation control device 21 forms an image on a sheet based on CMYK color space image data input from the image processing device 20.
In the image formation control device 21, the device adjustment unit 220 adjusts the output of the exposure device or the development device with respect to either the positive image or the negative image. More specifically, the device adjustment unit 220 controls the exposure amount of the optical scanning device 140 (exposure device), and if further adjustment is required in addition to the adjustment of the optical scanning device 140, the parameter (development) of the developing device 156 Bias, applied energy, frequency, etc.) are controlled.

  The device adjustment unit 220 receives the difference from the difference reception unit 218 of the image processing apparatus 20 and adjusts these devices so that the positive character / line image quality is equivalent to that of the predecessor. For example, the device adjustment unit 220 increases the exposure amount of the optical scanning device 140 when the positive character / line drawing is thin, and decreases the exposure amount of the optical scanning device 140 when the positive character / line drawing is thick.

FIG. 7 is a flowchart showing device adjustment processing (S10) by the device adjustment unit 220.
As shown in FIG. 7, in step 100 (S100), the device adjustment unit 220 uses the difference received from the difference reception unit 218 so that the replaced character / line width of the image forming apparatus 10 is that of the preceding machine. It is judged whether it is thin compared with. If the positive character / line width is narrow, the device adjustment unit 220 proceeds to the process of S102, and otherwise proceeds to the process of S110.

In step 102 (S102), the device adjustment unit 220 controls to increase the exposure amount of the optical scanning device 140 so that the positive character / line width is printed thick.
In step 104 (S104), the device adjustment unit 220 further receives a difference between the printing result by the predecessor and the printing result by the image forming apparatus 10 after adjusting the exposure amount, and the exposure amount is adjusted based on this difference. It is determined whether the positive character / line width of the image forming apparatus 10 is narrower than that of the predecessor. If the positive character / line width is narrow, the device adjustment unit 220 proceeds to the process of S106, and if not, ends the device adjustment process.

In step 106 (S106), the device adjustment unit 220 adjusts the parameters of the developing unit 156 to control printing so that the positive character / line width is printed thick.
In step 108 (S108), the device adjustment unit 220 further accepts a difference between the printing result by the predecessor and the printing result by the image forming apparatus 10 after adjusting the exposure amount and the development parameter, and based on this difference, these adjustments are made. It is determined whether or not the positive character / line width of the image forming apparatus 10 subjected to is narrower than that of the predecessor. The device adjustment unit 220 returns to the process of S102 if the positive character / line width is thin, and ends the device adjustment process otherwise.

In step 110 (S110), the device adjustment unit 220 controls the optical scanning device 140 so that the exposure amount of the optical scanning device 140 is reduced and the positive character / line width is printed thin.
In step 112 (S112), the device adjustment unit 220 further receives a difference between the printing result by the predecessor and the printing result by the image forming apparatus 10 after adjusting the exposure amount, and the exposure amount is adjusted based on this difference. It is determined whether the positive character / line width of the image forming apparatus 10 is thicker than that of the predecessor. The device adjustment unit 220 proceeds to the process of S114 when the positive character / line width is thick, and ends the device adjustment process otherwise.

In step 114 (S114), the device adjustment unit 220 adjusts the parameters of the developing device 156 and controls the printing so that the positive character / line width is printed thin.
In step 116 (S116), the device adjustment unit 220 further accepts a difference between the printing result by the predecessor and the printing result by the image forming apparatus 10 after adjusting the exposure amount and the development parameter, and based on this difference, these adjustments are made. It is determined whether or not the positive character / line width of the image forming apparatus 10 subjected to is thicker than that of the predecessor. The device adjustment unit 220 returns to the process of S110 if the positive character / line width is thick, and ends the device adjustment process otherwise.

  In this way, the device adjustment unit 220 can ensure the consistency of the positive character / line image quality of the predecessor and the replaced image forming apparatus 10. For this reason, the print quality can be maintained at a level expected by a user familiar with the predecessor.

FIG. 8 is a flowchart showing image drawing adjustment processing (S20) by the image drawing unit 200.
As shown in FIG. 8, in step 200 (S <b> 200), the image drawing unit 200 determines that the negative character / line width of the replaced image forming apparatus 10 is based on the difference received from the difference receiving unit 218. It is judged whether it is thin compared with. The image drawing unit 200 proceeds to the process of S202 when the negative character / line width is thin, and proceeds to the process of S210 otherwise.

In step 202 (S202), the image drawing unit 200, based on the PDL, the font weight and the line width (that is, the width value of the stroke part describing the line in the language and the width value of the fill for drawing a rectangle). Adjust so that negative characters and line widths are printed thicker.
In step 204 (S204), the image drawing unit 200 further accepts a difference between the printing result by the predecessor and the printing result by the image forming apparatus 10 after adjustment of the line width and the like, and the line width and the like are adjusted based on this difference. It is determined whether the negative character / line width of the image forming apparatus 10 is narrower than that of the predecessor. The image drawing unit 200 proceeds to the process of S206 when the negative character / line width is thin, and ends the image drawing adjustment process otherwise.

In step 206 (S206), the image drawing unit 200 performs edge extraction processing, expands the edge image area, and adjusts so that the negative character / line width is printed thick.
In step 208 (S208), the image drawing unit 200 further accepts a difference between the print result by the predecessor and the print result by the image forming apparatus 10 after adjustment by edge processing or the like, and based on this difference, these adjustments are performed. It is determined whether the negative character / line width of the image forming apparatus 10 made is narrower than that of the predecessor. The image drawing unit 200 returns to the process of S202 when the negative character / line width is thin, and ends the image drawing adjustment process otherwise.

In step 210 (S210), the image drawing unit 200 adjusts the font weight and the line width based on the PDL so that the negative character / line width is printed thinly.
In step 212 (S212), the image drawing unit 200 further accepts a difference between the printing result by the predecessor and the printing result by the image forming apparatus 10 after adjustment of the line width and the like, and the line width and the like are adjusted based on this difference. It is determined whether the negative character / line width of the image forming apparatus 10 is thicker than that of the predecessor. The image drawing unit 200 proceeds to the process of S214 when the negative character / line width is thick, and ends the image drawing adjustment process otherwise.

In step 214 (S214), the image drawing unit 200 performs edge extraction processing, shrinks the edge image area, and adjusts so that the negative character / line width is printed thin.
In step 216 (S216), the image drawing unit 200 further receives a difference between the printing result by the predecessor and the printing result by the image forming apparatus 10 after the adjustment by the edge processing or the like, and based on this difference, these adjustments are performed. It is determined whether the negative character / line width of the image forming apparatus 10 made is thicker than that of the predecessor. The image drawing unit 200 returns to the process of S210 if the negative character / line width is thick, and ends the image drawing adjustment process otherwise.

  In this way, the image drawing unit 200 can suppress the influence on the negative character / line width due to the device adjustment process (FIG. 7; S10). For this reason, the image drawing unit 200 can ensure the consistency of the negative character / line image quality of the predecessor and the replaced image forming apparatus 10.

FIG. 9 is a flowchart showing the correction data adjustment process (S30) by the color conversion data adjustment unit 214 and the gradation correction data adjustment unit 216.
As shown in FIG. 9, in step 300 (S300), the gradation correction data adjustment unit 216 determines that the primary color (CMYK) of the replaced image forming apparatus 10 is based on the difference received from the difference reception unit 218. It is judged whether or not it is deviated from that of the previous aircraft. The gradation correction data adjustment unit 216 proceeds to the process of S302 when the primary color is shifted, and ends the correction data adjustment process otherwise.
In step 302 (S302), the gradation correction data adjustment unit 216 adjusts the one-dimensional LUT stored in the gradation correction data storage unit 212, and the gradation correction unit 204 eliminates the primary color shift. To be.

In step 304 (S304), the color conversion data adjustment unit 214 determines that the replaced secondary color (RGB) or tertiary color of the image forming apparatus 10 is based on the difference received from the difference reception unit 218. It is determined whether or not it is shifted. The color conversion data adjustment unit 214 proceeds to the process of S306 if the secondary color or the like is shifted, and ends the correction data adjustment process otherwise.
In step 306 (S306), the color conversion data adjustment unit 214 adjusts the three-dimensional LUT stored in the color conversion data storage unit 210, and the color conversion unit 202 eliminates the shift of the secondary color or the like. Like that.

  In this way, the color conversion data adjustment unit 214 and the gradation correction data adjustment unit 216 are affected by the positive line drawing being thickened (for example, the gradation reproduction of the halftone region that is in the dot gain state is increased, The highlight reproduction becomes stronger, the maximum density increases, etc.). In addition, the color conversion data adjustment unit 214 and the gradation correction data adjustment unit 216 adjust the influence (for example, dotless state, reduction in highlight reproduction, reduction in maximum density, etc.) caused by making the positive line drawing thinner. Can do.

FIG. 10 is a flowchart showing the adjustment process (S40) of the image forming apparatus 10 according to the present invention.
As shown in FIG. 10, in step 400 (S400), the image forming apparatus 10 accepts a difference between a printing result by the predecessor and a printing result by the replaced image forming apparatus 10. In the process of S10, the image forming apparatus 10 adjusts the positive character / line image quality, which is the basic image quality, based on the difference, and then adjusts the negative character / line image quality in the process of S20. Further, if necessary, the image forming apparatus 10 adjusts the gradation correction data and the color conversion data in the process of S30.

FIG. 11 is a flowchart showing the overall operation (S50) of the image forming apparatus 10 according to the present invention.
As shown in FIG. 11, in step 500, the image processing device 20 receives image data requested to be printed by the user from the terminal device 2 via the network 3. The image processing apparatus 20 may accept image data (raster image) read via the image reading unit 12.

  In step 502 (S502), the image drawing unit 200 of the image processing apparatus 20 analyzes the PDL and draws an image. At this time, the image drawing unit 200 draws an image by switching the font weight and line width of the negative character / line drawing to adjusted values. Further, in the case of a rasterized negative character / line drawing, the image drawing unit 200 performs edge extraction processing and adjusts the line width by expanding or contracting the edge portion image area. The image drawing unit 200 outputs the image data drawn to the adjusted value to the color conversion unit 202.

In step 504 (S504), the color conversion unit 202 converts the input RGB color space data into image data in the CMYK color space using the adjusted three-dimensional LUT stored in the color conversion data storage unit 210. Convert. The color conversion unit 202 outputs the image data after color conversion to the gradation correction unit 204.
Note that the color space handled by the color conversion unit 202 is not particularly limited, and the color conversion unit 202 may perform color conversion between arbitrary color spaces.

In step 506 (S506), the gradation correction unit 204 corrects the gradation of each input color of CMYK using the adjusted one-dimensional LUT stored in the gradation correction data storage unit 212. The gradation correction unit 204 outputs the image data after gradation correction to the image formation control device 21.
In step 508 (S508), the image formation control device 21 forms an image of the image data input from the image processing device 20 on a sheet under the adjusted exposure amount and developing device parameters.

  As described above, the image forming apparatus 10 according to the present invention includes at least one device that forms an image, a generation unit that selectively generates a positive image and a negative image with respect to an input image, and the generation unit. A first adjustment unit (device adjustment unit 220) that adjusts the output of the device with respect to one of a positive image and a negative image by the image, and the other image of the positive image and the negative image by the generation unit. And a second adjusting unit (image drawing unit 200) that adjusts by processing. Thereby, according to the image forming apparatus 10, the consistency of the basic image quality can be maintained even when the image forming apparatus such as a multifunction peripheral is replaced.

  Further, the image forming apparatus 10 according to the present invention adjusts positive characters and line drawings, which are basic image quality, so that the quality desired by the user can be maintained. Since the image forming apparatus 10 performs image processing such as adjustment of the line width and edge region, it is possible to provide the image quality of negative characters and line drawings while ensuring the basic image quality.

  Furthermore, according to the image forming apparatus 10 according to the present invention, for example, when a large number of image forming apparatuses are replaced, adjustment time and labor cost in factory shipment can be reduced, and no response in the market is required. It can be. This can also reduce the cost required for market engineers.

1 shows an image forming system 1 including an image forming apparatus 10 according to an embodiment of the present invention. FIG. 3 is a diagram illustrating replacement of a plurality of image forming apparatuses connected via a network. FIG. 3A illustrates an image quality difference in an image forming apparatus before and after replacement. FIG. 3A illustrates an image printed by the image forming apparatus before replacement, and FIG. 2 illustrates an image printed by an image forming apparatus. It is a figure explaining the adjustment method of the image quality in the image forming apparatus 10 which concerns on this invention. 1 is a diagram illustrating a configuration of a tandem type image forming apparatus 10 according to the present invention. 2 is a block diagram illustrating functional configurations of an image processing device 20 and an image formation control device 21. FIG. It is a flowchart which shows the device adjustment process (S10) by the device adjustment part 220. 5 is a flowchart showing image drawing adjustment processing (S20) by the image drawing unit 200. 10 is a flowchart showing correction data adjustment processing (S30) by the color conversion data adjustment unit 214 and the gradation correction data adjustment unit 216. 4 is a flowchart showing adjustment processing (S40) of the image forming apparatus 10 according to the present invention. 4 is a flowchart showing an overall operation (S50) of the image forming apparatus 10 according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image reading unit 14 Image forming unit 20 Image processing apparatus 21 Image formation control apparatus 22 Image detection sensor 140 Optical scanning device 156 Developer 200 Image drawing part 202 Color conversion part 204 Tone correction part 206 Positive image output part 208 Negative image output unit 210 Color conversion data storage unit 212 Tone correction data storage unit 214 Color conversion data adjustment unit 216 Tone correction data adjustment unit 218 Difference reception unit 220 Device adjustment unit

Claims (13)

At least one device for forming an image;
Generating means for selectively generating a positive image and a negative image with respect to an input image;
First adjusting means for adjusting the output of the device with respect to any one of a positive image and a negative image by the generating means;
An image forming apparatus comprising: a second adjusting unit that adjusts the other of the positive image and the negative image by the generating unit by image processing. The device has an exposure apparatus,
The image forming apparatus according to claim 1, wherein the first adjustment unit adjusts an exposure amount of the exposure apparatus. The device has a developing device,
The image forming apparatus according to claim 1, wherein the first adjusting unit adjusts a parameter of the developing device. The image forming apparatus according to claim 1, wherein the second adjustment unit adjusts a thickness of a line included in the image. The image forming apparatus according to claim 1, wherein the second adjustment unit adjusts an edge region included in the image. Color conversion data adjustment means for adjusting color conversion data based on the adjustment results by the first adjustment means and the second adjustment means;
The image forming apparatus according to claim 1, further comprising a color conversion unit that performs color conversion on an image based on the color conversion data adjusted by the color conversion adjustment unit. Gradation correction data adjustment means for adjusting gradation correction data based on the adjustment results by the first adjustment means and the second adjustment means;
The image forming apparatus according to claim 1, further comprising: a gradation correction unit that performs gradation correction on an image based on the gradation correction data adjusted by the gradation correction data adjustment unit. A difference extracting means for extracting differences between a plurality of output images output based on one image data;
The image forming apparatus according to claim 1, wherein the first adjustment unit adjusts an output of the device based on a difference extracted by the difference extraction unit. A difference receiving means for receiving a difference between a plurality of output images output based on one image data;
The image forming apparatus according to claim 1, wherein the first adjustment unit adjusts an output of the device based on a difference received by the difference reception unit. In an image forming apparatus having at least one device for forming an image,
Selectively generate positive and negative images for the input image,
Adjusting the output of the device with respect to any one of the generated positive image and negative image;
An image forming method for adjusting the other of the generated positive image and negative image by image processing. Adjusting the device output in the image forming apparatus to match one of the positive image and the negative image output from the other image forming apparatus,
An image adjustment method for adjusting the other of a positive image and a negative image by image processing corresponding to one of a positive image and a negative image in the image forming apparatus. In an image forming apparatus having a computer and at least one device for forming an image,
A generation step of selectively generating a positive image and a negative image with respect to the input image;
A first adjustment step of adjusting an output of the device with respect to any one of the generated positive image and negative image;
A program for causing a computer of the image forming apparatus to execute a second adjustment step of adjusting the other of the generated positive image and negative image by image processing. In an image forming apparatus including a computer,
A first adjustment step of adjusting a device output in the image forming apparatus so as to match one of a positive image and a negative image output from another image forming apparatus;
A program for causing the computer of the image forming apparatus to execute a second adjustment step of adjusting the other of the positive image and the negative image by image processing corresponding to one of the positive image and the negative image in the image forming apparatus.

Images