JP2005017562A - Image forming apparatus and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and an image forming system having a mode for saving toner consumed in a photographic area by discriminating the photographic area without lowering the density of a character part being a main information source in the case of outputting an image. <P>SOLUTION: The image forming apparatus where the image is formed and printed with the toner based on image data has a photographic area detection means 26 detecting the photographic area included in the image data by receiving toner saving designation for saving the toner, and an image processing means 24 performing image processing based on an image processing method for roughly dividing the contrast of a photograph in the photographic area detected by the detection means 26 to states where the toner is stuck/is not stuck. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus and an image forming system having an eco mode for suppressing toner consumption.
[0002]
[Prior art]
Examples of the image forming apparatus include a black and white or color copying machine, a printer, a facsimile, or a multifunction machine in which a plurality of these functions are combined. Recently, most of such image forming apparatuses are digital, and it has become possible to faithfully output images of various originals. For this reason, since it is possible to easily output a high-quality image from a document having a continuous tone characteristic such as a photograph, the output from such a document is performed more frequently than before.
[0003]
In the case of a normal character document, for example, even if characters are written on almost the entire area of an A4 size paper, the toner portion (image portion) occupies about several percent of the paper area. However, even if, for example, an area about 1/4 of the A4 size is a photograph and the remaining area is a character, the toner consumption may be about ten times that when the entire area is a character. Therefore, when reading and copying magazines and catalogs containing photos with an image forming device, or when printing manuals with photos etc. from an information processing device to the image forming device, a large amount of text is included for the photos. Of toner will be consumed.
[0004]
Therefore, in Patent Document 1, in the image forming apparatus, when it is detected that the toner saving mode is selected and the remaining amount of toner is low, the exposure amount by the laser is reduced or the photosensitive member is made uniform. It has been proposed to reduce the density of the entire image by lowering the voltage of the main charger that is charged at a low voltage. Further, it has been proposed to save toner consumption by printing a toner-saving character having a smaller number of dots than a normal print character.
[0005]
Patent Document 2 discloses a printer that sets a developing bias value so as to suppress toner consumption or reduces the exposure amount by a laser when the toner saving mode is selected.
[0006]
[Patent Document 1]
JP 10-319789 A [Patent Document 2]
Japanese Patent Application Laid-Open No. 6-14167
[Problems to be solved by the invention]
However, the methods proposed in Patent Document 1 and Patent Document 2 decrease the total toner density in order to reduce the charge amount, development bias value, or exposure amount by the main charger, and read the output character part. The problem of becoming difficult occurs. In Patent Document 1, since the dots constituting the character are further thinned out, the character becomes more difficult to judge. As described above, according to the conventional technique, although the amount of toner consumed by the output image can be saved, there is a problem that it is difficult to read the character portion which is a main information source. Further, even if the density of the entire image to be output can be suppressed to some extent, for example, if the photographic part has a size that cannot be ignored as described above, even if the toner consumption by the photographic part is suppressed to some extent, There are not always enough savings.
[0008]
The present invention has been made for such a situation, and at the time of outputting an image, the photographic area is determined and consumed in the photographic area without reducing the density of the character part which is the main information source. An object of the present invention is to provide an image forming apparatus and an image forming system having a mode for saving toner.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in an image forming apparatus that forms and prints an image with toner based on image data, a photographic area included in the image data is received in response to a toner saving instruction for saving toner. Photographic area detecting means for detecting, and image processing means for performing image processing based on an image processing method for roughly classifying the shade of the photograph of the photographic area detected by the photographic area detecting means into a state where toner is attached or not. Have.
[0010]
The image processing method includes a photographic area blanking process in which the photographic area is blanked so as not to be printed with toner.
[0011]
The image processing method includes photo contour processing for extracting the contour (edge) of photographic image data in a photographic area and converting the shading of the photograph into a contour.
[0012]
When a photographic area is detected, a toner saving amount calculating means for calculating a toner saving amount based on the image processing method is further provided.
[0013]
The toner saving amount calculated by the toner saving amount calculating means is output for display.
[0014]
The image processing method is determined and set based on the displayed toner saving amount.
[0015]
In an image forming apparatus that forms and prints an image with toner based on image data, a toner saving instruction means for saving toner, and a photo area included in the image data in response to the toner saving instruction by the toner saving instruction means Photographic area detecting means for detecting, image processing means for performing image processing for roughly classifying the shade of the photograph of the photographic area detected by the photographic area detecting means into a state where toner is attached or not, and a plurality of image processing methods A toner saving amount calculating means for calculating a toner saving amount when the image processing is performed based on the image processing, and a toner saving amount for each image processing method calculated by the toner saving amount calculating means, Image processing method selection means for selecting one image processing method.
[0016]
The image processing method includes a photographic area blanking process in which the photographic area is blanked so as not to be printed with toner.
[0017]
The image processing method includes photo contour processing for extracting the contour (edge) of photographic image data in a photographic region and converting the shading of the photograph into a contour.
[0018]
To save toner in an image forming system comprising an information processing apparatus connected via a communication medium and an image forming apparatus that forms and prints an image with toner based on image data output from the information processing apparatus A toner saving instruction means; a photograph area detecting means for detecting a photographic area included in the image data in response to the toner saving instruction by the toner saving instruction means; and a density of a photograph in the photographic area detected by the photographic area detecting means. Image processing means for performing image processing for roughly classifying the toner into a state where toner is not attached or not, and a toner saving amount for calculating a toner saving amount when printing is performed by image processing based on a plurality of image processing methods Displaying a toner saving amount for each image processing method calculated by the calculating unit and the toner saving amount calculating unit, and selecting one image processing method. And an image processing method selection unit.
[0019]
The image processing method includes a photographic area blanking process in which the photographic area is blanked so as not to be printed with toner.
[0020]
The image processing method includes photo contour processing for extracting the contour (edge) of photographic image data in a photographic region and converting the shading of the photograph into a contour.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the details of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an example of a digital image forming apparatus to which the present invention is applied. The image forming apparatus 1 includes an automatic document feeder 2 that feeds a bundle of documents set on a document feeding table 2a one by one, a document reading unit 4 that converts a fed document into read image data, The operation unit 3 includes a display unit 3a and an operation input unit 3b, a printing unit 8, and a control unit 20 that performs all these controls. The printing unit 8 further stores the paper P and feeds the paper P to the paper P by forming an image on the photosensitive member and the paper feeding unit 5 including the first paper feeding unit 5a and the second paper feeding unit 5b. The image forming unit 6 to be performed, the registration roller 16 that temporarily stops and bends the sheet P fed from the sheet feeding unit 5 and feeds it to the image forming unit 6, and the fixing unit that fixes the image to the sheet P 7 and a discharge tray 9 that receives the paper P discharged via the discharge roller 22 and accumulates and stores the paper P.
[0022]
Further, the image forming unit 6 exposes the photosensitive member 10 that rotates clockwise in the drawing, a charging unit 11 that charges the surface of the photosensitive member 10, and the charged photosensitive member 10 to form an electrostatic latent image. An exposure unit 12; a developing unit 13 that develops the electrostatic latent image as a visible image with toner via a developing roller 13a; a transfer unit 14 that transfers the visible image of the toner onto the paper P; And a cleaning unit 15 that removes residual toner not transferred to the surface of the photoconductor 10.
[0023]
The above configuration will be specifically described with reference to a block diagram. FIG. 2 is a block diagram showing the main part of the image forming apparatus 1 according to the present invention. The main control unit 20a constituting a part of the control unit 20 described with reference to FIG. 1 includes an operation unit 3 including a display unit 3a and an operation input unit 3b, a document reading unit 4, and read image data. An image memory 23 for temporarily storing image data, a photo area detecting means for detecting a photo area of the image data, an image processing unit 24 for performing image processing on the image data and the photo area, a paper feeding unit 5, and an image forming unit 6 and the fixing unit 7 are connected. As another component, the automatic document feeder 2 is connected via an automatic document feeder I / F (interface) 2b, and has a printer function for printing by receiving print data from an information processing device (not shown). The printer controllers 25 are connected to each other.
[0024]
As described above, the image forming apparatus 1 according to the present embodiment includes a copy function of performing image processing on the image data of the document read by the document reading unit 4 by the image processing unit 24 and then printing by the printing unit 8 (FIG. 1). A printer function that performs image processing on image data of print data composed of image data input from an information processing apparatus and a print command via a network control circuit (not shown) and a print command; Have.
[0025]
Next, a case where a photographic image is included in the image data read by the document reading unit 4 and stored in the image memory 23 or the image data stored in the image memory 23 via the printer controller 25 will be described. FIG. 3 is a histogram showing the density (0 to 255) of each pixel constituting the image data of the photograph and the frequency (number) for each density on the horizontal axis and the vertical axis, respectively, and (a) is an example. , (B) is another example.
[0026]
Usually, since image data of a photograph shows continuous gradation, a histogram that draws a gentle curve as shown in FIG. Depending on the type of photograph, there is a histogram in which the peak of the curve is biased from the center as shown in FIG. In addition, some histograms have two or three peaks. As described above, although the number and position of the peaks vary depending on the type of photograph, the pixels of the photograph are widely distributed over a range of density 0 to 255. However, a histogram of a certain region including black or gray characters, lines, or area portions has a frequency of 0 in a wide density range, and has a sharp mountain only near a specific density, for example, near 0 and 255.
[0027]
A photograph in which each pixel is distributed in such a wide density range is a portion that consumes a large amount of toner. In general, in the case of a general manuscript composed of photographs and characters, the main information source is characters. In many cases, the contents of information can be understood even if there is no photograph or only the outline of the photograph contents. In the present invention, in the case of a general manuscript in which such characters and photographs are mixed, a photograph portion is detected, and the portion is blanked so as not to be printed at all, or the photograph is processed to be represented by an outline. That is, printing is performed after image processing for roughly classifying the shade of a photograph into a state in which toner is attached or not, thereby suppressing toner consumption.
[0028]
For this reason, if the image area detection means 26 (FIG. 2) divides the entire image data into a plurality of areas and analyzes the histogram, the photograph area where the photograph is located can be easily detected based on the characteristics of the histogram of the photograph. It becomes possible. When the detection of the photographic area is completed, the portion may be replaced with a blank, or the image processing unit 24 (FIG. 2) may perform image processing so that the content of the photographic image becomes a line drawing with a contour.
[0029]
Next, an image processing method for making the image data in the photographic area blank and an image processing method for expressing the contents of the photograph with outlines will be described with reference to FIG. FIG. 4 is a diagram for explaining the outline of the spatial filtering process using a 3 × 3 neighborhood area in the image processing. FIG. 4A shows the density of the pixel to be processed, and FIG. 4B shows its multiplier. (Operator) is shown, and (c) is an expression for obtaining a new density f ′ (x, y) of the target pixel. When such a spatial filtering process is performed, the new density f ′ (x, y) of the target pixel is multiplied by the values at the same positions in FIGS. 4A and 4B, and the sum is obtained. That method is given by the equation shown in FIG.
[0030]
FIG. 5A shows an operator's value for blanking the detected photo area using this spatial filtering. In addition, FIG. 5B shows operator values for contouring the contents of the photograph in the extracted photograph area. In FIG. 5A, since the values of all operators are 0, the new density value of the target pixel is 0 where no toner adheres. That is, the new density of all pixels in the photographic area is 0 (blank).
[0031]
In FIG. 5B, the operator value of the pixel of interest is 4, and the operator values of the pixels on the two diagonal lines are -1. Therefore, the new density of the region having the same density becomes 0, and at the same time, the density of the portion where the density has changed is further increased. That is, only a portion where the density change is abrupt and large is extracted as a new pixel. Therefore, the content of the photograph looks like a line drawing represented by an outline (edge). As can be seen from this explanation, the toner is not consumed when the photo portion is blank. Further, when the contour process is performed, the photograph is drawn as if it were a line, so that the consumption of toner can be greatly suppressed.
[0032]
When the image forming apparatus 1 of the present embodiment is used as a copier, a printer installed in an information processing apparatus (not shown) is set according to settings from the operation unit 3 (FIG. 1) or when used as a printer. The process related to the eco mode can be performed by setting via the screen provided by the driver software. An example of this will be described by taking printer driver software on the information processing apparatus as an example.
[0033]
FIG. 6 is a print setting screen by printer driver software for the image forming apparatus 1 installed in the information processing apparatus. When a document is opened from predetermined application software and a printing procedure is executed, a print screen 30 is displayed on the information processing apparatus. In the device selection box 31 of the print screen 30, the image forming apparatus 1 is selected as an output destination, the output range and the number of output copies are set as desired, and the “eco mode” is selected in the mode selection box 32. If image processing for saving toner is not performed on the photo portion, “normal” is selected.
[0034]
When the “eco mode” is selected and the “OK” button is pressed, the print data of the document is sent from the information processing apparatus to the image forming apparatus 1. The print data is read into the image forming apparatus 1 and processing described later is performed. 7 ends, the screen shown in Fig. 7 is displayed on the information processing apparatus, and Fig. 7 is a processing selection screen that is displayed when a photo area is detected when the eco mode is selected.
[0035]
The processing selection screen 40 includes a device display box 41, a toner saving amount display box 42, and a processing method selection box 43. The apparatus display box 41 shows the image forming apparatus 1 that has already been selected. When the eco mode is selected, the image forming apparatus 1 has the number of dots (the number of pixels) of the entire image data sent from the information processing apparatus, the number of dots in the photographic area, and the dots when the photographic area is contoured. The amount of toner saved when performing blank processing and the amount of toner saved when performing contour processing are displayed as percentages, respectively, as compared to the case where the number is calculated and the photograph portion is printed as it is. To display.
[0036]
The user compares the toner saving amount displayed in the toner saving amount display box 42 and, in the processing method selection box 43, “prints the photo with blank processing”, “prints the photo with contour processing”, or Select either “Print photo as it is”. When the “OK” button is pressed, the selection is transmitted from the information processing apparatus to the image forming apparatus 1, and the image forming apparatus 1 performs printing based on the selected processing method. The “Cancel” button is pressed. Then, all processing related to the printing is stopped.
[0037]
The screens shown in FIGS. 6 and 7 and the display and setting via those screens are the same as those of the display unit 3a of the operation unit 3 (FIG. 1) when the image forming apparatus 1 is used as a copying machine. This is performed via the operation input unit 3b. In this case, the document is read by the document reading unit 4 and converted into image data.
[0038]
Next, the process flow described so far will be described with reference to FIG. FIG. 8 is a flowchart showing a toner consumption saving procedure based on the present embodiment. When the image forming apparatus 1 is used as a copying machine, in S1 (step 1), settings relating to the copying work are performed, and at the same time, the document is read by the document reading unit 4 and converted into image feed data. When the printer is used as a printer, document image data and a print command are input from the information processing apparatus. In S2, a check is made as to whether or not the eco mode is selected according to the setting relating to copying and the print command. If the eco mode is not selected, normal copying or printing is performed in S3 and the process is terminated.
[0039]
If the eco mode is selected, the process branches to S10, and the total number of dots of the read or input image data is counted as D0. Thereafter, in S11, a photographic part is detected from the image data, and in S12, the number of dots in the photographic part is counted as D1. In S13, the contour processing of the photograph content is performed, and in S14, the number of dots in the photograph portion after the contour processing is counted to be D2.
[0040]
In S15, D1 / D0 is calculated, and the toner saving amount when the photograph is blanked in the eco mode is displayed in%. Further, (D1-D2) / D0 is calculated, and the toner saving amount when the contour processing of the photograph is performed in the eco mode is displayed in%. The display in this case is performed on the operation unit 3 or the information processing apparatus. An example of the display is as shown in FIG. Based on the amount of toner saved by each displayed image processing, the user selects an image processing method in S16. An example thereof is as shown in FIG.
[0041]
If the user selects not to perform the toner saving process in S16, the process branches to S3, and the normal printing is completed. If the processing for blanking the photographic part is selected in S16, the process branches to S17, and the photographic part of the already detected image data is converted into an image using the spatial filtering operator shown in FIG. Process. Thereafter, printing is performed in S18 based on the processed image data, and the process ends. When the contour processing of the photographic part is selected in S16, the process branches to S20, based on the image data that has already undergone the contour image processing in S13, or using the spatial filtering operator shown in FIG. New contour image processing is performed on the photograph portion of the original image data. Thereafter, printing is performed in S21 based on the processed image data, and the process is terminated.
[0042]
The above description is based on the image forming apparatus 1 shown in FIG. 1, but for example, even if the image forming apparatus 1 is a color image forming apparatus, the toner is basically processed in the same procedure. It is possible to reduce consumption. In that case, if a histogram of density is similarly analyzed for RGB composite image data or YMCK composite image data, a photo portion can be extracted. Further, each operator shown in FIG. 5 may be applied to each color pixel of YMCK.
[0043]
In addition, when making a photo part blank, it may be more preferable to perform a process of enclosing with a thin frame line in order to indicate that there is a picture in that part. If necessary, you can add “Process the photo part blank and enclose it with a frame line” in the selection method of the processing method selection box in FIG. Good.
[0044]
【The invention's effect】
As is apparent from the above description, according to the present invention, image processing for toner saving is performed on the photographic part of the extracted image data, so that the character information as the main information source is not difficult to read and the toner consumption is reduced. It has an excellent effect that it is possible to suppress this.
[0045]
In addition, since the blanking process and the outline process can be performed on a photographic part occupying a large part of toner consumption, a significant toner saving effect can be expected as compared with the conventional technique in which an image is thinned as a whole. Even in that case, it is possible to select a selection branch in which the photograph is represented by an outline and the photograph information is left so as not to cause complete loss of the photograph information.
[0046]
Further, the present invention can also be used for a color image forming apparatus. In this case, since there is a great saving effect for each color toner of YMCK, a remarkable toner saving effect can be realized as a whole.
[Brief description of the drawings]
FIG. 1 shows an example of a digital image forming apparatus to which the present invention is applied.
FIG. 2 is a block diagram showing a main part of the image forming apparatus 1 according to the present invention.
FIG. 3 is a histogram showing the density (0 to 255) of each pixel constituting the image data of the photograph and the frequency for each density on the horizontal axis and the vertical axis, respectively. ) Is another example.
FIGS. 4A and 4B are diagrams for explaining an overview of spatial filtering processing using a 3 × 3 neighborhood area in image processing, where FIG. 4A shows the density of a pixel to be processed, and FIG. 4B shows its multiplier; (Operator) is shown, and (c) is an expression for obtaining a new density f ′ (x, y) of the target pixel.
FIGS. 5A and 5B are values of an operator for spatial filtering according to the present embodiment, where FIG. 5A is an operator value for making the entire photo area blank, and FIG. 5B is an outline of the photo content in the photo area. The value of the operator.
FIG. 6 is a print setting screen by printer driver software for the image forming apparatus 1 installed in the information processing apparatus.
FIG. 7 is a processing selection screen displayed when a photo area is detected when the eco mode is selected.
FIG. 8 is a flowchart showing a toner consumption saving procedure according to the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Automatic document feeder 2a Original feeding stand 2b Automatic document feeder I / F
3 Operation unit 3a Display unit 3b Operation input unit 4 Document reading unit 5 Paper feed unit 5a, 5b Paper feed unit 6 Image forming unit 7 Fixing unit 8 Printing unit 9 Discharge tray 10 Photoconductor 11 Charging unit 12 Exposure unit 13 Development unit 13a Developing roller 14 Transfer section 15 Cleaning section 16 Registration roller 20 Control section 20a Main control section 22 Discharge roller 23 Image memory 24 Image processing section 25 Printer controller 26 Photo area detection means 30 Print screen 31 Device selection box 32 Mode selection box 40 Process selection Screen 41 Device display box 42 Toner saving amount display box 43 Processing method selection box

Claims (12)

In an image forming apparatus that forms and prints an image with toner based on image data,
Upon receipt of a toner saving instruction for saving toner, the toner adheres to the photographic area detecting means for detecting the photographic area included in the image data, and the density of the photograph in the photographic area detected by the photographic area detecting means. An image forming apparatus comprising: an image processing unit that performs image processing based on an image processing method that is broadly classified into a state of not performing. The image forming apparatus according to claim 1, wherein the image processing method includes a photographic area blanking process in which the photographic area is blanked so as not to be printed with toner. 3. The image processing method according to claim 1, wherein the image processing method includes a photographic contour process that extracts a contour (edge) of photographic image data in the photographic region and converts the density of the photograph into a contour. Image forming apparatus. 4. The image according to claim 1, further comprising toner saving amount calculation means for calculating a toner saving amount based on the image processing method when the photographic area is detected. Forming equipment. The image forming apparatus according to claim 1, wherein the toner saving amount calculated by the toner saving amount calculating unit is output for display. 6. The image forming apparatus according to claim 5, wherein the image processing method is determined and set based on the displayed toner saving amount. In an image forming apparatus that forms and prints an image with toner based on image data,
A toner saving instruction means for saving toner, a photo area detecting means for detecting a photographic area included in the image data in response to a toner saving instruction by the toner saving instruction means, and a detection by the photographic area detecting means. Image processing means for performing image processing for roughly classifying the shade of a photograph in a photograph area into a state where toner is attached or not, and toner saving when image processing is performed based on the plurality of image processing methods and printing is performed A toner saving amount calculating means for calculating the respective amounts, an image processing method selecting means for displaying a toner saving amount for each of the image processing methods calculated by the toner saving amount calculating means, and selecting one image processing method. An image forming apparatus comprising: The image forming apparatus according to claim 7, wherein the image processing method includes a photographic area blanking process for blanking the photographic area so as not to be printed with toner. 9. The image processing method according to claim 7, wherein the image processing method includes a photographic contour process that extracts a contour (edge) of photographic image data in the photographic region and converts a shading of the photographic image into a contour. Image forming apparatus. In an image forming system comprising an information processing apparatus connected via a communication medium and an image forming apparatus that forms and prints an image with toner based on image data output from the information processing apparatus.
A toner saving instruction means for saving toner, a photo area detecting means for detecting a photographic area included in the image data in response to a toner saving instruction by the toner saving instruction means, and a detection by the photographic area detecting means. Image processing means for performing image processing for roughly classifying the shade of a photograph in a photograph area into a state where toner is attached or not, and toner saving when image processing is performed based on the plurality of image processing methods and printing is performed A toner saving amount calculating means for calculating the respective amounts, an image processing method selecting means for displaying a toner saving amount for each of the image processing methods calculated by the toner saving amount calculating means, and selecting one image processing method. An image forming system comprising: The image forming system according to claim 10, wherein the image processing method includes a photographic area blanking process for blanking the photographic area so as not to be printed with toner. 12. The image processing method according to claim 10, wherein the image processing method includes a photo contour process for extracting a contour (edge) of photographic image data in the photographic region and converting a shading of the photograph into a contour. Image forming system.

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