JPH0969945A - Image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a desired optimum image and to improve the usability of image formation by converting image density information according to half- tone reproduction characteristics of an image forming device when a half-tone image is formed, and displaying the covnerted image information. SOLUTION: When a multilevel half-tone image is printed, a user freely sets conditions required for thresholding such as the number of lines, a screen angle, a dot shape or γ correction. Or default values are set unless the user sets the condtions required for thresholding. Once the condtions are set, a host computer explodes (thresholding) the data and the original half-tone image is saved. Then image density information is converted according to the γcharacteristics of the printer so that the user can confirm an actually printed binary image (output image of the printer). Even when the image density information is the same, there is a visual density difference of a paper surface from a display screen, so visual sensation corrections are made so as to correct the difference, and the corrected image is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming system for forming an image according to a command from an image information processing device and image information.

[0002]

2. Description of the Related Art In a conventional printer, when a halftone image having multivalued density data displayed on a display is printed, a host computer converts the multivalued halftone image into a binary image and the host computer The binary image data is transferred from the computer to the printer for printing, or the multivalued halftone image data is sent from the host computer to the printer formatter, and the printer formatter converts the multivalued halftone image into a binary image. I was printing. Further, when a halftone image having multi-value density data is converted into a binary image and the binary image displayed on the display is printed, the binary image data is transferred from the host computer to the printer and printed. .

In any case, once printing is started, the print monitor showing the print status displayed on the display only shows that printing is in progress and printing is completed. In other words, the user can perform image processing such as density conversion and gradation conversion on the host computer, but it is only after printing that the user can understand how the converted image appears in the print result. .

[0004]

However, in the above-mentioned conventional example, when a halftone image having multivalued density data is printed by the printer, a binary image is printed even if it is printed in the state of multivalued halftone image. Even if the image is printed in this state, since it has the conversion characteristic of the display and the γ characteristic of the printer, it is not a multi-valued halftone image or binary image with high gradation desired by the user as displayed on the display. Different images are printed. Here, the conversion characteristic of the display is a characteristic that, when the input image data is displayed on the display, conversion is performed so that each input image data value corresponds to a certain luminance and a grayscale image is displayed. .

The inventor of the present invention has set the number of lines to 2 in an actual machine (printer) having a resolution of 600 dpi and a spot diameter of 80 μm.
12 lines / inch, a screen angle of 45 degrees, and a halftone dot shape of a circle were set, and a multivalued intermediate image was printed by setting conditions for binarization.

FIG. 13 is a diagram showing the relationship between the density and the brightness of the input image data on the display of the host computer. The horizontal axis represents the density of the input image data, and the larger the number, the darker the image.

FIG. 14 is a diagram showing the relationship between the density information of 0 (white) and 255 (black) of the input image data of the display of the host computer and the density of the image data converted by the characteristics of the display. It is assumed that the density changes linearly with the image information.

FIG. 15 is a diagram showing the relationship between the density information of 0 (white) and 255 (black) of the input image data on the display of the host computer and the density of the output image of the printer. Similarly, it is assumed that the density changes linearly with the image information.

Comparing FIG. 14 and FIG. 15, there is a difference between the density of the input image data of the display of the host computer and the density of the image data converted by the characteristics of the display and the density of the output image of the printer, and ,
As the density of the image information 255 (black), the density of the image data converted according to the characteristics of the display is higher than the density of the output image of the printer, so a multivalued halftone image (image data) is displayed on the display. This is an image with less smooth gradation and lower density than a multi-valued halftone image (grayscale image on the display).

The .gamma. Characteristic of the printer is the input-output density characteristic of the printer body, as shown in FIG. FIG. 7 is a diagram showing a density histogram of image data obtained from an image input device or the like by the γ characteristic of an actual machine (printer) and a printer output image converted by the γ characteristic of the printer.

In the case of printing with an actual machine, since the γ characteristic of the printer stands as shown in FIG. 6, the output image of the printer is not smoother in gradation than the multivalued halftone image (image data), and γ It is a standing image.

As described above, due to the conversion characteristic of the display and the γ characteristic of the printer, the image has a high gradation and is a beautiful image, but the output image of the printer has almost no toner developed in the small density area. From the density area to the high density area, it is crushed in black, the gradation is not smooth and the image becomes γ, and the output image of the printer can be imagined by the user from the multi-value halftone image displayed on the display. An image with poor gradation is printed.

Therefore, since there is no means for the user to know what kind of image is output from the printer, it is not possible to know what kind of image will be output unless the user prints it, and the paper is wasted. , It often happened that the time wasted wasted because it had to be retaken.

Further, from now on, there is a demand for outputting a high-resolution image having a high number of lines and gradation, and the higher the number of lines, the more the γ characteristic becomes less linear, and the γ curve has a multi-value gradation. Since the image quality becomes low, the difference between the image displayed on the display and the output image of the printer becomes remarkable, and there is a tendency that it is far from the halftone image or the binary image having the gradation that the user desires.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an image forming system capable of obtaining an optimum image desired by a user and improving the convenience of the image forming apparatus. To aim.

[0016]

To achieve the above object, the present invention provides an image forming system for forming an image according to a command from an image information processing device and image information,
When forming a halftone image, the image density information is converted according to the halftone reproduction characteristics of the image forming apparatus, and the image information of the converted density is output and displayed on the display device of the image information processing device. And

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a diagram showing a system composed of a host device and a printer device.
In the figure, reference numeral 1 is a printer device using an electrophotographic method. Reference numeral 2 is a host device such as a mini computer, a workstation or a personal computer, which is connected by a communication cable 3. And the communication cable 3
Signals and image information relating to the operation of the printer device 1 are exchanged via the. In the example shown in FIG. 1, one-to-one connection is made, but a plurality of host devices and a plurality of printer devices may be connected on the network. In that case, an arbitrary combination of the host device and the printer device can be selected and operated on the network.

FIG. 2 is a view showing the control panel of the printer device 1 displayed on the display device of the host device 2. As shown in the figure, the control panel has paper size, reduction ratio, enlargement ratio, print direction, number of copies,
Information 4 such as paper feed and print pattern, and a printout image desired by the user such as the number of lines, screen angle, halftone dot shape or γ correction for binarization when printing out a multi-valued graphic image are displayed. It includes information 5 that is essential for obtaining.

Further, the symbol ⊚ shown in the information 4 indicates the selected one, and if these pieces of information are not set by the user, they are set to default. Then, the information set on the control panel is sent to the printer device 1 through the communication cable 3.

FIG. 3 is a diagram showing the flow of processing according to the first embodiment. As shown in the figure, when printing the input image (halftone image) data, the image density information is converted according to the γ characteristic of the printer contained in the printer driver installed in the host computer, and the same image information 255 Since the density of (black) is different on the display and on the paper, the image density information is converted according to the characteristics of the display, and the visually corrected image is displayed on the display.

In FIG. 4, when printing a multi-valued halftone image in the first embodiment, the host computer performs two operations such as halftone screen and transfer function correction.
It is a flowchart when performing a value conversion. Also, FIG.
6 is a flowchart for printing a binary image according to the first embodiment.

The inventor of the present invention used a real machine (printer) having a resolution of 600 dpi and a spot diameter of 80 μm to print a multivalued halftone image. In this embodiment, when printing a multi-value halftone image, the user freely sets the conditions necessary for binarization such as the number of lines, screen angle, halftone dot shape or γ correction (step S101). . Here, the number of lines is 212 lines / inch, the screen angle is 45 degrees, the halftone dot shape is a circle, and the conditions for binarization are set. Also,
If the user does not set the conditions required for binarization, the default is set. Then, when the conditions are set, the data is developed (binarized) by the host computer, and the original multi-valued halftone image is stored (step S102).

Next, the image density information is converted according to the γ characteristic of the printer so that the user can confirm the binary image (printer output image) that is actually printed out. Further, even if the image density information is the same, since there is a difference in the apparent densities on the display and on the paper, visual correction for correcting the difference is performed, and the corrected image is displayed on the display (step S103). However, the information of the γ characteristic for each line number of the printer is stored in the printer driver. Here, the printer driver is driver software for the host computer to control printing.

That is, at the time of printing, conversion is performed according to the characteristics of the display, image density information is converted according to the γ characteristics of the printer, and an image visually corrected so that the apparent density difference between the display and the paper is eliminated is displayed on the display. indicate. At times other than printing, an image in which density information has been converted according to the conversion characteristics of the display is displayed on the display as usual.

FIG. 6 shows the γ characteristic of the actual machine (printer), which is the input image of the printer main body-the output image density characteristic of the printer. FIG. 7 shows a density histogram of the image data obtained from the image input device and the output image of the printer.

The user performs conversion according to the characteristics of the display displayed on the display, converts the image density information according to the γ characteristics of the printer, and is visually corrected to eliminate the apparent density difference between the display and the paper. It is determined whether the image can be printed (step S10).
4) If it is judged to be good, the binary image data is transferred to the printer and printed out. However, if the user decides that he / she does not want to print the image displayed on the display, the multi-valued halftone image data stored in the host computer is read (step S105), and the number of lines, the screen angle, and the halftone dot are again displayed. Necessary conditions for binarization such as point shape or γ correction are set, and halftone image data is developed.

Also, when printing a binary image, as in the case of printing a multi-valued halftone image, the binary image actually printed out is displayed on the display so that the user can confirm it before printing. To do. That is, conversion is performed according to the characteristics of the display, density information is converted according to the γ characteristics of the printer, and an image visually corrected so that there is no apparent density difference between the display and the paper is displayed on the display (step S201). ). Then, when the user determines that the image displayed on the display may be printed (Yes in step S202), the image data is transferred from the host computer to the printer and printed out. However, if the user decides that he does not want to print the image displayed on the display (step S
No of 202), the multi-valued halftone image data stored in the host computer is read (step S20).
3), the number of lines, screen angle, halftone dot shape, γ correction, and other necessary conditions for binarization are reset (step S
204), the host computer expands the halftone data (step S205).

As described above, according to the first embodiment, although it takes a little longer than the conventional printing, the user does not redo the printing by the above-described method. The time is shorter than when printing is restarted without obtaining the desired image, waste of paper and toner can be prevented, and higher definition (high resolution, high gradation) images can be printed. Therefore, the optimum image desired by the user can be obtained more reliably.

(Second Embodiment) FIG. 8 is a diagram showing the flow of processing according to the second embodiment. As shown
When printing a halftone image, it is converted according to the display characteristics that were used when the application was used on the host computer, and according to the γ characteristics of the printer contained in the printer driver transferred from the host computer to the printer. Even if the image density information is converted by using the display and the conversion characteristic of the display is canceled, the density of the same image information 255 (black) is different on the display and on the paper, so the visually corrected image is displayed on the display. is there.

FIG. 9 is a flow chart in the case of performing a binarization such as a correction by a halftone screen or a transfer function in the printer when printing a multivalued halftone image in the second embodiment.

In the present embodiment, the inventor also printed a multi-valued halftone image on an actual machine (printer) having a resolution of 600 dpi and a spot diameter of 80 μm.
In the present embodiment, when printing a halftone image, first, multi-valued image data is transferred to the printer (step S30).
1). Next, the number of lines, screen angle, halftone dot shape, or γ
A user freely sets conditions necessary for binarization such as correction. Here, the number of lines is 212 lines / inch, the screen angle is 45 degrees, the halftone dot shape is a circle, and the conditions for binarization are set. If the user does not set the condition required for binarization, the default condition is set (step S302). Next, the printer expands (binarizes) the data (step S303). Then, the binary image data expanded from the printer is transferred to the host (step S304). The binary image (printed image output from the printer) that is actually printed is converted according to the characteristics of the display so that the user can check it before printing.
Further, since the printer has the γ characteristic, the image density information is converted according to the characteristic. Furthermore, even if the image density information is the same, since there is a difference in density between the appearance on the display and the appearance on the paper, visual correction is performed to correct the difference, and the corrected image is displayed on the display (step S305). However, the information on the γ characteristic for each line number of the printer is installed in the host computer by the printer driver and transferred from the host computer to the printer.

That is, at the time of printing, the image is converted according to the characteristics of the display, the density information is converted according to the γ characteristics of the printer, and the image visually corrected so that the apparent density difference between the display and the paper is eliminated is displayed on the display. The image is displayed and the image in which the density information is converted according to the conversion characteristic of the display is displayed on the display as usual except when printing.

The user performs conversion according to the characteristics of the display displayed on the display, converts image density information according to the γ characteristics of the printer, and is visually corrected so that there is no apparent density difference between the display and the paper. It is determined whether the image can be printed (step S30).
6) If it is judged to be good, print out. When the user decides that he / she does not want to print the image displayed on the display, the original multi-valued image data stored in the host computer is read (step S307), transferred to the printer, and the number of lines and the screen angle are re-established. , Set the conditions necessary for binarization such as halftone dot shape or γ correction,
Expand the halftone image data on the printer.

As described above, according to the second embodiment,
Since the data is expanded by the printer, the host computer can be operated even in the printer during the data expansion. Also, in the present embodiment, as in the first embodiment, although it takes more time than the conventional printing, the above-described method prevents the user from reprinting the print. It is possible to prevent waste of paper and toner, and to print higher-definition (high-resolution, high-gradation) images, because the time is slightly shorter than when printing is restarted without obtaining the desired image. Therefore, the optimum image desired by the user can be obtained more reliably.

(Third Embodiment) FIG. 10 is a diagram showing the flow of processing according to the third embodiment. As shown in the figure, when printing a halftone image, it is converted according to the characteristics of the display that was used when the application was used on the host computer, and the γ of the printer included in the printer driver installed on the host computer. The image density information is converted according to the characteristics, at the same time, the image forming conditions contained in the printer driver installed in the host computer are changed to create a plurality of image density information, and the same image information 255 (black) Since the densities are different on the display and on the paper, a plurality of visually corrected images are displayed on the display.

FIG. 11 shows a case of performing binarization such as correction by a halftone screen or a transfer function when printing a multivalued halftone image in the third embodiment.
7 is a flow chart for displaying a plurality of images with different image forming conditions on a display. In the present embodiment, the inventor of the present invention also has a resolution of 600 dpi and a spot diameter of 80 μm.
The multi-valued halftone image was printed on the actual machine (printer) of. However, in this embodiment, a printer that can change the image forming conditions is used. When printing a multivalued halftone image, the user freely sets conditions necessary for binarization such as the number of lines, screen angle, halftone dot shape, or γ correction (step S401). Here, the number of lines is 212 lines / inch and the screen angle is 45.
The degree and the dot shape are circles, and the conditions for binarization were set.
If the user does not set the conditions required for binarization,
Set default conditions. Next, the host computer expands (binarizes) the data (step S40).
2). The binary image actually printed out (output image of the printer) is converted in accordance with the characteristics of the display at the time of printing so that the user can check it before printing. Then, since the printer has the γ characteristic, the image density information is converted according to the characteristic, and at the same time, the image forming condition is changed to create a plurality of image density information (step S40).
3). Further, even if the image density information is the same, since there is a density difference between the appearance on the display and the appearance on the paper, visual correction is performed to correct the difference, and the corrected image is displayed on the display. However, the information of the γ characteristic for each line number of the printer and the information of the variable image forming conditions are entered in the printer driver.

That is, at the time of printing, conversion is performed according to the characteristics of the display, image density information is converted according to the γ characteristics of the printer, image forming conditions are changed, and a plurality of pieces of image density information are created to make the appearance on the display and on paper. A plurality of images that have been visually corrected to eliminate the difference in density are displayed on the display, and the image in which the density information has been converted according to the conversion characteristics of the display is displayed on the display as usual, except during printing (step S404).

In the present embodiment, the image forming conditions of the dark portion potential on the drum and the DC component of the developing bias are changed. FIG. 12 is a diagram showing the image forming conditions of the printer, showing the normal image forming condition (F5), the image forming condition (F1) that is darker than the normal image, and the image forming condition (F9) that is lighter than the normal image. ing.

The user converts according to the characteristics of the display, converts the latitude information of the brain according to the γ characteristics of the printer, and at the same time creates three pieces of image density information with different image forming conditions, and looks them on the display and on paper. Judging from the three images displayed on the display that have been visually corrected to eliminate the difference in density, if any one of the images is judged to be good (Yes in step S405), data expansion is started in the host computer. , The binary image data is transferred to the printer, and is printed out under the image forming conditions when it is determined to be good. Further, the user does not want to print any of the three display images in which the conversion is performed according to the characteristics of the display displayed on the display, the density information is converted according to the γ characteristics of the printer, and the image forming conditions are changed. If it is determined (No in step S405), the multivalued halftone image data stored in the host computer is read (step S406), and the simple binary value such as the number of lines, the screen angle, the halftone dot shape, or the γ correction is read. Reconfigure the conditions necessary for data conversion and expand the data on the host computer.

As described above, according to this embodiment, although it takes a little longer than the conventional printing, the user does not redo the printing, so that the image desired by the user cannot be obtained by the conventional printing method. The time is shortened compared to the case of re-printing, the waste of paper and toner can be prevented, and multiple images with different image forming conditions are displayed on the display. It is possible to more reliably obtain an image by reducing the number of times of binarization.

The present invention may be applied to a system including a plurality of devices such as a host computer, an interface, and a printer, or may be applied to an apparatus including a single device such as a copying machine. Further, it goes without saying that the present invention can be applied to a case where the program stored in a storage medium is achieved by being supplied to a system or an apparatus.

[0043]

As described above, according to the present invention,
When printing a halftone image or a binary image, it is converted according to the characteristics of the display before being output by the printer, the density information is converted according to the γ characteristics of the printer, and the apparent density difference between the display and the paper is converted. By displaying the image that has been visually corrected so as to eliminate the problem on the display, the user can recognize what kind of image is output, and thus the optimum image desired by the user can be obtained with one print output. If the image desired by the user is not displayed on the display, the print output may be stopped and the image conversion may be performed again, so that there is no print failure and the waste of paper and toner can be prevented.

[0044]

[Brief description of drawings]

FIG. 1 is a diagram illustrating a system including a host device and a printer device.

FIG. 2 is a control panel of a printer device displayed on a host device.

FIG. 3 is a diagram showing a display process during printing of a halftone image according to the first embodiment.

FIG. 4 is a flowchart showing a display process of a halftone image according to the first embodiment.

FIG. 5 is a flowchart showing a display process of a binary image according to the first embodiment.

[FIG. 6] The resolution is 600 dpi and the number of lines is 212 lines / in.
It is a figure which shows the γ characteristic of the printer at the time of ch.

FIG. 7 is a diagram showing a density histogram of input image data and a density histogram of an output image of a printer.

FIG. 8 is a diagram showing a display process at the time of printing a halftone image according to the second embodiment.

FIG. 9 is a flowchart showing a display process of a halftone image according to the second embodiment.

FIG. 10 is a diagram showing a display process at the time of printing a halftone image according to the third embodiment.

FIG. 11 is a flowchart showing a display process of a halftone image according to the third embodiment.

FIG. 12 is a diagram showing image forming conditions of a printer used in the third embodiment.

FIG. 13 is a diagram showing the relationship between the density of image data input to the host computer and the brightness.

FIG. 14 is a diagram showing the relationship between the density of input image data of a host computer and the density of image data converted according to the characteristics of a display.

FIG. 15 is a diagram showing the relationship between the density of input image data on the display of the host computer and the density of the output image of the printer.

[Explanation of symbols]

 1 Printer 2 Host 3 Communication cable

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Claims (8)

[Claims] 1. An image forming system for forming an image according to a command from an image information processing device and image information, wherein when forming a halftone image, image density information is converted according to a halftone reproduction characteristic of the image forming apparatus. Then, the image forming system is characterized in that the converted image information of the density is outputted and displayed on the display device of the image information processing equipment. 2. The image forming system according to claim 1, wherein the halftone reproduction characteristic is previously input to an image information processing apparatus via a driver for controlling the operation of the image forming apparatus. 3. An image forming system for forming an image according to a command from an image information processing device and image information, wherein when forming a halftone image, the halftone image data is transferred to the image forming apparatus, Converting the image density information according to the halftone reproduction characteristics, transferring the converted density image information to the image information processing device, and outputting the transferred image information to the display device of the image information processing device for display. An image forming system characterized by. 4. An image forming system for forming an image according to a command from an image information processing device and image information, wherein when forming a halftone image, a plurality of image forming conditions are used to meet the halftone reproduction characteristics of the image forming apparatus. The image forming system is characterized in that the image density information is converted respectively and the converted image information of a plurality of densities is output and displayed on the display device of the image information processing device. 5. The image forming system according to claim 1, wherein when the image displayed on the display device is not the display desired by the user, the conversion condition can be newly set. . 6. An image forming system for forming an image according to a command from an image information processing device and image information, wherein when forming a halftone image, image density information is converted according to a halftone reproduction characteristic of the image forming apparatus. An image forming system, comprising: a conversion unit that performs the conversion, and a display unit that outputs and displays the image information of the density converted by the conversion unit on a display device of an image information processing device. 7. The image forming system according to claim 6, wherein the halftone reproduction characteristic is a γ characteristic of an image forming apparatus. 8. The image forming system according to claim 6, further comprising setting means for setting conditions for converting the halftone image into a binary image.