JP3710224B2 - Image processing apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus capable of correcting variations in image output characteristics of an image output apparatus.
[0002]
[Prior art]
Recently, a system for outputting color image data sent from a host computer to a color printer via a controller connected on a network is provided. For example, a user who has a host computer and a color copying machine prints out a color image created on the host computer by using a controller connected to the network by using the color copying machine as a printer. It becomes possible.
[0003]
[Problems to be solved by the invention]
However, due to differences in printer characteristics of individual color printers, there is often a problem that a color different from the color intended by the user is printed out. Recently, a PostScript Printer Description file (hereinafter referred to as a PPD file) has been provided in order to eliminate the difference in color reproducibility due to the engine characteristics of the printer. Simply speaking, this PPD file absorbs differences in color reproducibility between the display of the host computer and the color printer, and differences in printer characteristics depending on the type of color printer, realizing faithful color reproducibility independent of the device. It is a file to be enabled. Although this PPD file can correct the difference in color reproducibility depending on the type of printer engine, there are actually individual differences in the print engine of the same model, and the user intended because of subtle differences in color reproducibility. The color is not always reproduced faithfully.
[0004]
Accordingly, the present invention provides individual differences in output characteristics in order to eliminate differences in color reproducibility due to individual differences in output characteristics that occur when an image from an information processing apparatus such as a host computer is output to an image output apparatus such as a printer. An object of the present invention is to provide an image processing apparatus and method capable of correcting the above.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is an image processing apparatus connectable to a plurality of image output apparatuses,
Storage means capable of storing correction data corresponding to the image output device in association with identification information of the image output device;
When one of the plurality of image output apparatuses is selected, the identification number of the selected image forming apparatus is read, and it is determined whether there is a correction table corresponding to the read identification number in the storage unit. Determination means,
If there is no determination result correction table, inquiry means for inquiring whether to output a test pattern to the user,
And a control unit that outputs the test pattern when a test pattern output request is made as a result of the inquiry and creates correction data corresponding to the selected image output apparatus .
[0006]
An image processing method for an image processing device connectable to a plurality of image output devices,
Storing correction data corresponding to the image output device in a storage unit that can be stored in association with identification information of the image output device;
When one of the plurality of image output apparatuses is selected, the identification number of the selected image forming apparatus is read, and it is determined whether there is a correction table corresponding to the read identification number in the storage unit. ,
If there is no determination result correction table, the user is asked whether to output a test pattern,
When a test pattern output request is made as a result of the inquiry, the test pattern is output, and correction data corresponding to the selected image output device is created .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment of the present invention, in order to invent the above problem, in an image processing system including an information processing device, an image processing device, and an image output device, the image processing device includes:
First input means for inputting image data from the information processing apparatus;
A second input means for inputting data from the image output device;
Expansion means for expanding the image data input to the first input means into raster image data;
Storage means for storing raster image data expanded by the expansion means and data input to the second input means;
Correction means for performing correction when raster image data developed by the development means is written to the storage means based on the data input to the second input means;
The image forming apparatus reads out image data read from the storage means and outputs the information to the information processing apparatus and the image output apparatus.
[0008]
By using the image processing apparatus as described above, it is possible to eliminate differences in color reproducibility due to individual differences in output characteristics of image output apparatuses such as printers. Therefore, when color image data created by a host computer or the like is output to a printer, an image faithful to the color intended by the user can be output, and the color reproducibility change due to aging of the image output device can be reduced. It can also be resolved.
[0009]
The preferred embodiments of the present invention will be specifically described below.
[0010]
(Example 1)
The first embodiment of the present invention will be described below. In the following embodiments, system examples of a host computer (information processing apparatus), an image processing apparatus, and an image forming apparatus are shown. However, the present invention is not limited to this and can be applied to various other apparatuses. In this embodiment, the image processing apparatus includes a plurality of host computers connected to the network, an image processing apparatus, a digital image reading unit for color / grayscale images, and an image forming unit for printing out the color / grayscale digital images. An image forming apparatus is used.
[0011]
FIG. 1 is a block diagram illustrating an image processing system including a host computer 10, an image processing apparatus 20, and an image forming apparatus 30. The image forming apparatus 30 is composed of two upper and lower parts. The upper image reading unit 31 is a part that reads a document at a resolution of 400 dpi (dot / inch) and performs digital signal processing. The lower image forming unit 32 is an image corresponding to the document image read by the image reading unit 31. This is a part for outputting an image sent from the host computer 10 in a color or gray scale to a recording medium at a resolution of 400 dpi.
[0012]
First, the image reading unit 31 will be described with reference to FIGS. 1 and 2. In FIG. 2, a document table glass (not shown) is fixed on the upper surface of the document table 44 of the image reading unit 31, and the document set on the document table glass is an exposure lamp and mirror of the document illumination unit 43. (Not shown) is reciprocated along the lower surface of the platen glass to be exposed and scanned during the forward movement. The reflected light is sent to the light receiving unit 45 through a lens and a mirror (not shown). In the light receiving section 45, full color information of red (R), green (G), and blue (B) components is converted into an electrical signal (analog signal) corresponding to the density of each pixel by a CCD line sensor (not shown). This electrical signal is sent to the image processing unit 46, and is subjected to A / D conversion for each of R, G, and B colors by the image processing unit 46 and then electrically processed to obtain cyan (C), magenta (M), yellow ( Y) and black (K) components are separated and sent to the image forming unit 32. These operations are controlled by the control circuit unit 42 in accordance with data input from the operation unit 41. In addition, the image data scanned by the image reading unit 31 can be sent to the host computer 10 or the like via the image processing apparatus 20. At this time, the image signal (digital signal converted by the image processing unit 46 described above) Signal) is sent to the image processing apparatus 20 via the signal line 3.
[0013]
Next, the image forming unit will be described with reference to FIGS. The C, M, Y, and K image signals sent from the image reading unit 40 are sent to the laser driving unit 51. The laser driver 51 modulates and drives the semiconductor laser in accordance with each transmitted image signal. The laser light is passed through a polygon mirror, a lens, and a mirror (not shown), on the photosensitive drum (not shown) whose surface charge is uniformly charged by the primary charging unit 53 after the surface charge is removed by the pre-exposure unit 52. Scan. In the laser exposure unit 54, an electrostatic latent image is formed on a photosensitive drum scanned with a laser, and the electrostatic latent image is constituted by a magenta developing unit, a cyan developing unit, a yellow developing unit, and a black developing unit (not shown). When the toner is attached at the developing unit 55, a visible image is formed.
[0014]
The recording medium supplied from the paper supply unit 60 temporarily stands by in the registration unit 61 and is conveyed to the transfer unit 56 in accordance with the timing of rotation of the photosensitive drum. The recording medium is wound around a transfer drum (not shown) by the transfer unit 56, and an image formed on the photosensitive drum is transferred onto the recording medium. In this way, after the four colors C, M, Y, and K are sequentially transferred, the recording medium is separated by the separation unit 57, the recording medium is conveyed to the fixing unit 58, and the toner is fixed on the recording medium. Later, the paper is conveyed to a paper discharge unit 59 and discharged.
[0015]
An image signal input from an external device such as the host computer 10 via the image processing device 20 is sent to the laser driving unit 51 and printed in the same manner as described above.
[0016]
In this manner, the image forming apparatus 30 reads a document image on the document table of the image reading unit 31 to generate digital image data, and forms an image with the image forming unit 32, and an external input Has a remote print function to print the image data.
[0017]
The control unit 33 controls the entire image forming apparatus 30 and executes the above-described local copy function and remote print function according to the contents of communication with an operation unit (not shown) and the image processing apparatus 20.
[0018]
Next, the image processing apparatus will be described with reference to FIG. PDL (Page Description Language) image data sent from the host computer 10 via the interface 1 and the external interface 25 is temporarily stored in the PDL buffer 27-2 via the CPU bus. The CPU 21 develops the PDL image data stored in the PDL buffer 27-2 into raster image data using the font data stored in the ROM 22 or the built-in HDD 24, and writes the raster image data in the frame memory 27-1. At this time, the ROM 22 is used to hold a program, the HDD controller 24 controls the built-in HD, and the RAM is also used as a work RAM (not shown) for work.
[0019]
The image forming apparatus 30 is an electrophotographic color copying machine that performs image formation in a frame sequential manner for a plurality of output components C, M, Y, and K. The read address of each frame memory 27-1 is generated based on the figure. Then, raster image data is sent to the color conversion processing unit 29 via the CPU bus and the FIFO 28, and color conversion processing is performed. This color conversion processing unit 29 converts R, G, and B raster image data into C, M, Y, and K raster image data that can be printed by a color copying machine. The converted raster image data is sent to the image forming apparatus 30 as a forming signal 4, and image formation is performed based on the signal. The image processing apparatus 20 and the image forming apparatus 30 can perform various communications via the interface 2.
[0020]
Next, a method for creating a correction table will be described with reference to FIGS. The built-in HDD 24 of the image processing apparatus 20 holds test pattern data necessary for creating a correction table in advance. This test pattern data is R, G, B full-color image data in which all the gradations of 256 gradations exist. First, the test pattern data is sent to the image forming unit 32 of the image forming apparatus 30 and printed out (S41). Next, the printed out image is placed on the platen glass of the image reading unit 31 (S42) and scanned (S43). Image data (scanned image data) generated by scanning is held in the frame memory 27-1 of the image processing apparatus 20 via the signal line 3, the FIFO 28, and the CPU bus. Next, a correction program for creating a correction table is stored in advance in the built-in HDD 24. The density value of the scanned image data is read by this correction program, and the relationship between the density value as a reference and the read density value is determined. A correction table is created (S44) and stored in the built-in HDD 24 (S45). As described above, the correction table creation method has been described. However, the test pattern data stored in advance in the built-in HDD 24 does not necessarily have to have all 256 gradations. Just be fine.
[0021]
The image data correction method will be described below with reference to FIG. PDL image data sent from the host computer 10 via the interface 1 and the external interface 25 is temporarily stored in the PDL buffer 27-2 via the CPU bus. The CPU 21 expands the PDL image data stored in the PDL buffer 27-2 into raster image data using font data or the like stored in the ROM 22 or the built-in HDD 24. The developed raster image data is corrected by the CPU 21 using the correction table stored in the built-in HDD 24 created in advance as described above, and the corrected data is written in the frame memory 27-1.
[0022]
The address generation unit 26 generates a read address of each frame memory 27-1 based on a synchronization signal from the image forming apparatus 30, sends raster image data to the color conversion processing unit 29 via the CPU bus and the FIFO 28, and performs color conversion. Apply processing. This color conversion processing unit 29 converts R, G, and B raster image data into C, M, Y, and K raster image data that can be printed by a color copying machine. The converted raster image data is sent to the image forming apparatus 30 via the signal line 4 and image formation is performed.
[0023]
In the above description, the correction table creation method and the correction method for one image forming apparatus 30 connected to the image processing apparatus 20 have been described. However, when the image forming apparatus 30 is switched to another image forming apparatus, the image formation is performed. A correction table for the device must be created. First, a method for creating a correction table by identifying an image forming apparatus connected to the image processing apparatus will be described with reference to FIGS.
[0024]
The image forming apparatus 30 has an identification number for each individual, which is, for example, a barcode (outside the area used when the image reading unit 31 reads a document placed on the document table glass of the document table 44). (Not shown). When notifying the image processing apparatus 20 of the identification number of the image forming apparatus 30, the identification number data can be sent to the image processing apparatus 20 via the signal line 3 by scanning this barcode. The image processing apparatus 20 holds this identification number data in the built-in HDD 24.
[0025]
Further, after obtaining the identification number of the image forming apparatus 30 as described above, a correction table for the image forming apparatus 30 is created, so that the correction table created corresponding to the identification number of the image forming apparatus 30 is saved. It can be kept.
[0026]
Further, when the image forming apparatus 30 connected to the image processing apparatus 20 is connected to another image forming apparatus, a correction table for the newly connected image forming apparatus is required. Accordingly, a method for creating a correction table in the case of switching to another image forming apparatus will be described below with reference to FIGS.
[0027]
First, an image forming apparatus is selected (S50), and when another image forming apparatus is connected (S51), the image processing apparatus 20 reads the identification number of the connected image forming apparatus as described above. (S52), it is searched whether the correction table corresponding to the identification number is stored in the internal HDD 24 (S53). If there is no correction table corresponding to the identification number, the user is asked whether or not to output test pattern data (S54). When the user requests the output of the test pattern data, the test pattern data is output as described above (S55), and is set on the document table 44 (S56) and scanned (S57). And a correction table is created (S58). The created correction table is stored in the built-in HDD 24 in correspondence with the identification number of the image forming apparatus read earlier (S59).
[0028]
(Example 2)
First, differences from the first embodiment will be described. In the first embodiment, PDL image data sent from the host computer 10 is temporarily stored in the PDL buffer 27-2, and the PDL image data is developed into raster image data and written into the frame memory 27-1. At this time, the image data is corrected using the correction table stored in the built-in HDD 24. In this embodiment, the PDL image data sent from the host computer 10 is temporarily held in the PDL buffer 27-2. When the PDL image data is expanded into raster image data, the data is corrected. The correction method will be described below with reference to FIGS.
[0029]
As described in the first embodiment, the image forming apparatus 30 has an individual identification number, and when another image forming apparatus is connected (S61), the image processing apparatus 20 identifies the identification number. Is read (S62). Whether or not the read identification number is in the built-in HDD 24 is first searched (S63). If not, the user is asked whether or not to output test pattern data (S64), and an output request for test pattern data is made. If there is, the test pattern data is output (S65). The output test pattern data is set on the document table 44 (S66) and scanned (S67), the density value is read, and a correction parameter is created by a correction program stored in the built-in HDD 24 in advance (S68). Then, it is stored in the built-in HDD 24 in correspondence with the identification number of the image forming apparatus (S69).
[0030]
The PDL image data sent from the host computer 10 is temporarily held in the PDL buffer 27-2 via the CPU bus. The stored PDL image data is developed into raster image data by the CPU 21. At this time, the image data is corrected at the time of development by using the correction parameters described above, and the corrected raster image data is written into the frame memory 27-1. The address generation unit 26 generates a read address of each frame memory 27-1 based on the synchronization signal from the image forming apparatus 30, sends the raster image data to the color conversion processing unit 29 via the FIFO 28, and performs color conversion processing. . This color conversion processing unit 29 converts R, G, and B raster image data into C, M, Y, and K raster image data that can be printed by a color copying machine. The converted raster image data is sent to the image forming apparatus 30 via the signal line 4 and image formation is performed.
[0031]
Although the embodiments of the present invention have been described as described above, the image forming apparatus 30 and the image processing apparatus 20 are separated in each embodiment, but may be integrated. Further, the image forming apparatus 30 is configured by integrating the image reading unit 31 and the image forming unit 32, but these may be configured as separate devices. Further, although the correction program for creating the correction table is stored in the built-in HDD 24 in advance, various parameters for correction by the user may be set in order to take into account the characteristics of the scanner.
[0032]
As described above, according to the embodiment of the present invention, when color image data is output from the host computer to the image forming apparatus via the image processing apparatus, color reproducibility due to individual differences in printer characteristics of the printer. You can eliminate the difference. Therefore, when color image data created by the host computer is output from various types of image forming apparatuses, an image faithful to the color intended by the user can always be output, and color reproduction due to aging of the printer It can also eliminate changes in sex.
[0033]
【The invention's effect】
As described above, according to the present invention, differences in color reproducibility due to individual differences in output characteristics that occur when an image is output from an information processing apparatus such as a host computer to an image output apparatus such as a printer can be eliminated. .
[Brief description of the drawings]
FIG. 1 is a block diagram of an image processing system.
FIG. 2 is a block diagram of an image reading unit of the image forming apparatus.
FIG. 3 is a block diagram of an image forming unit of the image forming apparatus.
FIG. 4 is a flowchart showing a method for creating a correction table.
FIG. 5 is a flowchart illustrating a method for reading the identification number of the image forming apparatus and creating a correction table in the first embodiment.
FIG. 6 is a flowchart illustrating a method of creating a correction parameter by reading the identification number of the image forming apparatus in the second embodiment.
[Explanation of symbols]
10 host computer 20 image processing apparatus 30 image forming apparatus

Claims (3)

An image processing device connectable to a plurality of image output devices,
Storage means capable of storing correction data corresponding to the image output device in association with identification information of the image output device;
When one of the plurality of image output apparatuses is selected, the identification number of the selected image forming apparatus is read, and it is determined whether there is a correction table corresponding to the read identification number in the storage unit. Determination means,
If there is no determination result correction table, inquiry means for inquiring whether to output a test pattern to the user,
An image processing apparatus comprising: control means for outputting the test pattern when a test pattern output request is made as a result of the inquiry and creating correction data corresponding to the selected image output apparatus.   The image processing apparatus according to claim 1, wherein the identification information is transmitted from the image output apparatus. An image processing method for an image processing device connectable to a plurality of image output devices,
Storing correction data corresponding to the image output device in a storage unit that can be stored in association with identification information of the image output device;
When one of the plurality of image output apparatuses is selected, the identification number of the selected image forming apparatus is read, and it is determined whether there is a correction table corresponding to the read identification number in the storage unit. ,
If there is no determination result correction table, the user is asked whether to output a test pattern,
An image processing method comprising: outputting a test pattern when there is a test pattern output request as a result of the inquiry, and creating correction data corresponding to the selected image output device .

Images