JP7700554B2 - Image processing device, image processing program, and image forming device - Google Patents

Description

The present invention relates to an image processing device, an image processing program, and an image forming device.

When reading a printed document image, image reading devices have a problem in that the light irradiated on the document is reflected randomly within the image reading device, and the signal level of the pixel of interest increases depending on the surrounding pixel structure in the imaging area (white flare phenomenon). For this reason, a technique is known that prevents the white flare phenomenon by determining a correction value for the amplified signal based on the read image.

Patent document 1 (JP Patent Publication 11-355636A) discloses an imaging device that electrically corrects and reduces flare to make the image easier to see. In the case of this imaging device, a reference flare that occurs with a light source that results in a predetermined brightness in the captured image according to the aperture value and focal length parameters of the optical system is stored in advance in a flare data memory. A state setting circuit then detects from the video signal an image portion that has a value greater than a predetermined value to estimate the brightness, and uses the reference flare to artificially generate a predicted flare that would occur if a light source with the estimated brightness were present, and subtracts this from the video signal using a subtractor. This reduces the flare.

However, in conventional image reading devices, the amount of variation in the read value is calculated from the read image. The read image is given both the amount of variation that occurs in the image reading device and the amount of variation that occurs in the image forming device. If the amount of read variation is estimated from such a read image and a correction value for the color variation is calculated, the correction value is calculated in a state that includes unnecessary variation caused by the image forming device. As a result, the color variation of the image is corrected with an inaccurate correction value, which causes a problem that affects image quality.

The present invention has been made in consideration of the above-mentioned problems, and aims to provide an image processing device, an image processing program, and an image forming device that can calculate an accurate correction value for color fluctuations and correct the color fluctuations of an image with this correction value, thereby improving image quality.

In order to solve the above-mentioned problems and achieve the object, the present invention has an image formation control unit that controls the image formation unit to form an image based on drawing data, a reading control unit that controls the reading unit to read the image formed by the image formation control unit, a reading variation amount generation unit that generates a reading variation amount of a reference image corresponding to the ratio between the reading value of a maximum reference image, which is an image of the maximum pixel value among the images of the drawing data, and the reading value of the reference image, which is an image of the drawing data, an additive image generation unit that generates an additive image by adding the reading variation amount of the reference image to the reference image, and a color variation correction amount generation unit that generates a color variation correction amount used for color variation correction during image formation by subtracting the additive image from the read image formed by the image formation unit and read by the reading unit, and supplies the color variation correction amount to the image formation control unit.

The present invention has the advantage that it is possible to calculate an accurate correction value for color variation, and by correcting the color variation of an image with this correction value, it is possible to improve image quality.

FIG. 1 is a diagram showing a system configuration of a printing system according to a first embodiment. FIG. 2 is a diagram showing a hardware configuration of the image forming apparatus. FIG. 3 is a diagram showing a schematic configuration and positional relationship of an image forming unit and a reading unit in the image forming apparatus. FIG. 4 is a functional block diagram of each function realized by the CPU of the image forming apparatus executing the read variation correction program stored in the storage unit. FIG. 5 is a flowchart showing the flow of the read variation generating operation in the read variation generating unit in FIG. FIG. 6 is a schematic diagram for explaining the operation of generating a reference image in a state in which the reading fluctuation amount is superimposed. FIG. 7 is a diagram showing the relationship between the position (main scanning position) of each pixel of the in-line sensor and the amount of flare. FIG. 8 is a diagram for explaining the relationship between the amount of read variation of the maximum read image superimposed on the white portion of a predetermined paper and the amount of read variation superimposed on the paper white portion of the reference image. FIG. 9 is a diagram for explaining the relationship between the amount of reading variation of the maximum read image superimposed on the white portion of a predetermined paper and the amount of reading variation superimposed on the reference image. FIG. 10 is a diagram for explaining the operation of calculating the read variation amount of the reference image based on the maximum read variation amount of the reference image, the read value of the reference image, and the read value of the maximum reference image. FIG. 11 is a functional block diagram of each function for storing the read variation amount corresponding to the paper type, which is realized by the CPU of the image forming apparatus executing the read variation amount correction program stored in the HDD. FIG. 12 is a flowchart showing the flow of a storage operation (reading characteristic acquisition mode) of the reading variation amount (reading characteristic) corresponding to the paper type, which is executed by the CPU of the image forming apparatus based on the reading variation amount correction program stored in the HDD. FIG. 13 is a schematic diagram of the reading characteristics table. FIG. 14 is a functional block diagram of each function realized by the CPU of the image forming apparatus executing a read variation correction program stored in a storage unit such as an HDD. FIG. 15 is a flowchart showing the flow of a color variation correction operation performed by the CPU of the image forming apparatus by executing a reading variation correction program using a reading characteristics table. FIG. 16 is a cross-sectional view of an inkjet type image forming apparatus provided in a printing system according to the third embodiment.

The printing system according to the embodiment will be described below with reference to the attached drawings.

[First embodiment]
(System Configuration)
Fig. 1 is a diagram showing the system configuration of a printing system according to a first embodiment of the present invention. In Fig. 1, the printing system according to the first embodiment of the present invention includes a client personal computer device (client PC) 101, a digital front end (DFE) 102, an image forming device 103, and a management server 104.

The client PC 101 is equipped with a display unit such as an LCD display, as well as input devices such as a mouse and a keyboard. The client PC 101 creates a print job for an image to be printed, and transmits it to the DFE 102 or the management server 104.

The DFE 102 receives a print job from the client PC 101 or the management server 104, creates drawing data using a RIP (Raster Image Processor) engine based on the received print job, and transmits the data to the image forming device 103.

The image forming device 103 performs image forming operations based on the drawing data received from the DFE 102.

The management server 104 manages print jobs received from the client PC 101. It also transmits print jobs to the DFE 102 upon request from the DFE 102.

(Hardware configuration of image forming apparatus)
Fig. 2 is a diagram showing a hardware configuration of the image forming apparatus 103. As shown in Fig. 2, the image forming apparatus 103 includes a CPU (Central Processing Unit) 301, a ROM (Read Only Memory) 302, a RAM (Random Access Memory) 303, a HDD (Hard Disc Drive) 304, an interface (I/F) 305, an image forming unit 306, and a reading unit 307. The HDD 304 may be another storage device such as an SSD (Solid State Drive).

The CPU 301 uses the RAM 303 as a working area and executes the programs stored in the ROM 302. The HDD (or SSD) 304 is used as a storage unit and stores predetermined settings and programs. As an example, in the case of the printing system of the first embodiment, a reading variation correction program is stored in this HDD 304. By executing this reading variation correction program, the CPU 301 calculates correction values for color variation correction and performs color variation correction of the image.

The I/F 305 is connected to the DFE 102, the client PC 101, and the management server 104. The I/F 305 is an interface that enables communication between the DFE 102, the client PC 101, and the management server 104 and the image forming device 103.

(Configuration of Image Forming Unit)
3 is a diagram showing a schematic configuration and positional relationship of an image forming unit 306 and a reading unit 307 in an image forming apparatus. As an example, in the case of the printing system of the first embodiment, a so-called electronic type image forming apparatus is provided as the image forming apparatus 103. In this electronic type image forming apparatus, the image forming unit 306 has a configuration in which photoconductor drums 403Y (yellow), 403M (magenta), 403C (cyan), and 403K (black) of each color are arranged along an intermediate transfer belt 402 as shown in FIG. Such an image forming unit 306 is a so-called tandem type image forming unit (hereinafter, collectively referred to as photoconductor drums 403).

That is, photoconductor drums 403Y, 403M, 403C, and 403K are arranged in order from the upstream side of the transport direction of intermediate transfer belt 402 along intermediate transfer belt 402, on which an intermediate transfer image is formed to be transferred to paper fed from paper feed tray 400 and transported by transport rollers 401.

A full-color image is formed by superimposing and transferring the images of each color developed with toner on the surface of the photosensitive drums 403 of each color onto the intermediate transfer belt 402. The full-color image thus formed on the intermediate transfer belt 402 is transferred, by the function of the transfer roller 404, onto the surface of the paper that has been transported along the path at the position closest to the paper transport path indicated by the dashed line in the figure.

The paper with the image formed on its surface is transported further, and the image is fixed (image formed) by the fixing roller 405. When performing double-sided printing, after the image is formed on the front side, the paper is transported to the reversal path 407 in the transport path, inverted, and then transported again to the position of the transfer roller 404.

The reading unit 307 is composed of in-line sensors 406a and 406b (hereinafter collectively referred to as in-line sensor 406). The in-line sensor 406 reads both sides of the paper by the fixing roller 405, and obtains read image data of the image fixed on the paper. Note that two in-line sensors 406 (406a, 406b) are not necessarily required, and either one will suffice. For example, if only one sensor 406a is provided, the sensor 406a reads when the front side is printed, and then the back side is printed and printed as is.

(Software configuration of image forming apparatus)
4 is a functional block diagram of each function realized by CPU 301 of image forming apparatus 103 executing a reading variation amount correction program stored in a storage unit such as HDD 304. By executing the reading variation amount correction program, CPU 301 realizes each function of printer control unit 601, reference image generation unit 602, reading variation amount generation unit 603, image formation control unit 604, print image reading unit 605, image comparison unit 606, and color variation correction amount generation unit 607, as shown in FIG.

The printer control unit 601 to the color variation correction amount generation unit 607 shown in FIG. 4 are realized in software using a reading variation amount correction program. However, all or part of these may be realized in hardware such as an integrated circuit (IC).

The reading variation correction program may be provided by recording it in the form of file information in an installable or executable format on a recording medium that can be read by a computer device, such as a CD-ROM or a flexible disk (FD). The reading variation correction program may be provided by recording it on a recording medium that can be read by a computer device, such as a CD-R, a DVD (Digital Versatile Disk), a Blu-ray (registered trademark) disk, or a semiconductor memory. The reading variation correction program may be provided by installing it via a network such as the Internet. The reading variation correction program may be provided by being pre-installed in a ROM or the like within the device.

The printer control unit 601 acquires an original image (RIP image: CMYK values) from the DFE 102. The reference image generating unit 602 generates a reference image (FIG. 6(a)) by converting the original image supplied in CMYK values into RGB values of R (red), G (green), and B (blue) based on a predetermined conversion table. The reference image generating unit 602 also supplies the read values (RGB values) of the maximum reference image generated by reading an unprinted portion (white portion of the paper) of a dedicated chart or the like with the reading unit 307 to the read variation generating unit 603.

The maximum read image that is the maximum observed value can be calculated based on the characteristics of the image forming device 103. The read variation amount generation unit 603 calculates the read variation amount to be added to the maximum reference image from the read variation amount correction calculation of the maximum read image. The read variation amount generation unit 603 calculates the read variation amount of the reference image by reflecting the difference (ratio) between the read value of the maximum reference image and the read value of the reference image supplied from the reference image generation unit 602 to the read variation amount of the maximum reference image (FIG. 6(d)). The read variation amount generation unit 603 also generates a reference image (FIG. 6(e)) to which this read variation amount has been added. The reference image to which the read variation amount has been added is an example of an added image. The read variation amount generation unit 603 is also an example of a read variation amount generation unit and an added image generation unit.

The image formation control unit 604 controls the image forming unit 306 to form a print image (FIG. 6B) based on the drawing data (RIP image: CMYK values) from the DFE 102 acquired by the printer control unit 601. The print image has the fluctuation amount from the image formation side superimposed on it. The print image reading unit 605 controls the inline sensor 406 described above to read the print image on which the fluctuation amount from the image formation side is superimposed. This generates a read image of the RGB values (FIG. 6C). The fluctuation amount from the image reading side is further superimposed on this read image. Therefore, the read image has both the fluctuation amount from the image formation side and the fluctuation amount from the image reading side superimposed on it.

The image comparison unit 606 subtracts a reference image onto which the read variation amount generated by the read variation amount generation unit 603 is superimposed from a read image onto which both the image formation side variation amount and the image reading side variation amount are superimposed, thereby generating an image formation side variation amount to be superimposed when a print image is formed by the image formation control unit 604.

The color variation correction amount generation unit 607 converts the image formation side variation amount supplied from the image comparison unit 606 in RGB values into CMYK values and supplies them to the image formation control unit 604 as color variation correction amounts. The image formation control unit 604 performs color correction based on this color variation correction amount, and then prints the original image from the printer control unit 601. This prevents the inconvenience of correcting even the image reading side variation amount that was not originally superimposed, and makes it possible to print the image by correcting only the variation amount superimposed on the image formation side. This makes it possible to improve image quality.

(Reading Fluctuation Amount Generation Operation)
Fig. 5 is a flowchart showing a flow of a generating operation of the reading variation amount in the reading variation amount generating unit 603 in Fig. 4. In step S1, the printer control unit 601 acquires an original image from the DFE 102 and supplies it to the reference image generating unit 602 and the image formation control unit 604.

In step S2, the reference image generating unit 602 converts the document image supplied in CMYK values into a reference image in RGB values based on a predetermined conversion table. Also in step S2, the reference image generating unit 602 generates a paper white value, which is the RGB value of the paper white part of the document image, and supplies it to the reading variation generating unit 603.

In step S3, the read variation amount generating unit 603 determines whether the maximum read variation amount, which is the read variation amount of the paper white portion, has been calculated. If the maximum read variation amount has not been calculated (step S3: No), in step S4, the read variation amount generating unit 603 calculates the maximum read variation amount based on the paper white value.

In Figure 7, the horizontal axis indicates the position of each pixel in the main scanning direction (main scanning position), which is the direction in which the pixels of the inline sensor 406 are arranged, and the vertical axis indicates the amount of flare. In other words, the vertical axis indicates the amount of reading variation for each main scanning position. In Figure 7, if the pixel located in the center of the pixels arranged in the main scanning direction is taken as the pixel of interest, it can be seen that the amount of reading variation for this pixel of interest is the largest, followed by pixels closer to the pixel of interest with larger amounts of reading variation.

Next, FIG. 8(a) shows the read value (white level) of the maximum read image, which is the maximum observed value, calculated based on the characteristics of the reading unit 307. Also, FIG. 8(b) shows the read variation amount superimposed on the maximum read image, calculated based on the read value of the maximum read image. In contrast, FIG. 8(c) shows the read value (white level) of the maximum reference image, which is the read value of the paper white part of the reference image generated by the reference image generating unit 602, and FIG. 8(d) shows the read variation amount superimposed on this maximum reference image.

The read value of the maximum read image shown in FIG. 8(a) and the read value of the maximum reference image shown in FIG. 8(c) are the white level read values (maximum read values). Therefore, the read fluctuation amounts (FIGS. 8(b) and 8(d)) superimposed on the maximum read image shown in FIG. 8(a) and the maximum reference image shown in FIG. 8(c) should match.

Therefore, the ratio of the read value of the maximum reference image shown in FIG. 9(a) to the read value of the reference image shown in FIG. 9(c) is equivalent to the ratio of the read variation of the maximum reference image shown in FIG. 9(b) to the read variation of the reference image shown in FIG. 9(d). That is, in the example shown in FIG. 9(a) and FIG. 9(c), between the read value of the maximum reference image and the read value of the reference image, there exists a rectangular recessed portion (= black level portion) shown in FIG. 9(c) as the "difference" between the two. In this case, there exists a "difference" in the read variation amount corresponding to the rectangular recessed portion (see FIG. 9(c)) between the read variation amount of the maximum reference image shown in FIG. 9(b) and FIG. 9(d) and the read variation amount of the reference image.

For this reason, in step S5 of the flowchart in FIG. 5, the read variation generating unit 603 multiplies the read variation of the maximum reference image shown in FIG. 10(b) by the ratio between the read value of the maximum reference image and the read value of the reference image, as shown in FIG. 10(c) and FIG. 10(d). This makes it possible to calculate the read variation (FIG. 10(a)) superimposed on the reference image.

In step S6, the read variation generating unit 603 adds the read variation superimposed on the reference image thus calculated to the reference image and supplies it to the image comparing unit 606. This completes the read variation generating operation shown in the flowchart of FIG. 5.

The image comparison unit 606 subtracts the reference image, on which the read fluctuation amount calculated as described above is superimposed, from the read image, on which both the fluctuation amount on the image formation side and the fluctuation amount at the time of image reading are superimposed, by being printed by the image formation control unit 604 and read by the print image reading unit 605. This makes it possible to calculate the color fluctuation correction amount, which is the fluctuation amount superimposed at the time of image formation. This color fluctuation correction amount is calculated for each print image and supplied to the image formation control unit 604. This makes it possible to accurately correct the color fluctuation amount superimposed at the time of printing for each print image, and to obtain a print image of good quality.

(Effects of the First Embodiment)
As is clear from the above description, the printing system of the first embodiment calculates the read fluctuation amount of the reference image by multiplying the ratio between the read value of the maximum reference image (white part of the paper) and the read value of the reference image to be printed by the read fluctuation amount of the maximum reference image. Then, the calculated read fluctuation amount of the reference image is added to the reference image. The reference image to which this read fluctuation amount is added is printed by the image formation control unit 604 and read by the print image reading unit 605, and is subtracted from the read image in which both the fluctuation amount during image formation and the fluctuation amount during image reading are superimposed, thereby generating a color fluctuation correction amount that extracts only the fluctuation amount during image formation. Then, the color fluctuation correction amount is used to correct the color fluctuation of the print image printed by the image formation control unit 604. This makes it possible to accurately correct the color fluctuation amount superimposed during printing, and to obtain a print image with good image quality.

[Second embodiment]
Next, a printing system according to a second embodiment will be described. The printing system according to the first embodiment performs a reading variation correction process on a read image obtained by printing and reading an original image in the image forming apparatus 103. When performing the reading variation correction process, the reading variation is detected based on a read image of a reference chart printed in advance in order to grasp the reading variation tendency.

Here, the amount of reading variation on the read image differs for each image forming device 103 and each paper type. For this reason, in the printing system of the second embodiment, the amount of reading variation and paper type information are associated and stored in a storage unit such as the HDD 304. Then, when printing is performed using the same image forming device and the same paper type, the amount of reading variation detected previously is reused. This makes it possible to avoid the troublesome task of obtaining the amount of reading variation again when printing again on paper of the same paper type. Note that this is the only difference between the first embodiment described above and the second embodiment described below. For this reason, only the differences between the two will be explained below, and duplicate explanations will be omitted.

(Storage operation of reading fluctuation amount corresponding to paper type)
In the case of the second embodiment, in the image forming apparatus 103, the reading variation amount for each paper type is detected in advance and stored in a storage unit such as the HDD 304. Fig. 11 is a functional block diagram of each function that stores the reading variation amount corresponding to the paper type, which is realized by the CPU 301 of the image forming apparatus 103 executing the reading variation amount correction program stored in the HDD 304. Fig. 12 is a flowchart showing the flow of the storage operation (reading variation amount acquisition mode) of the reading variation amount corresponding to the paper type, which is executed by the CPU 301 of the image forming apparatus 103 based on the reading variation amount correction program stored in the HDD 304.

In FIG. 11 and FIG. 12, when the user selects the "reading variation acquisition mode", in step S11, the DFE 102 supplies a chart image for printing a specific chart to the printer control unit 601. The printer control unit 601 controls the printing of this chart image via the image formation control unit 604.

In step S12, the print image reading unit 605 reads the printed chart image, and the reading characteristic generating unit 650 detects the reading variation amount (reading characteristic) based on the read image of the chart image and supplies it to the reading characteristic storage control unit 651.

In step S13, the reading characteristics storage control unit 651 acquires paper type information indicating the type of paper on which the chart image is printed from the printer control unit 601. The reading characteristics storage control unit 651 then stores the paper type information and the reading variation amount corresponding to that paper type in a storage unit such as the HDD 304 in association with each other. The operation of storing the reading variation amount corresponding to such a paper type is performed for each paper type. As a result, a reading characteristics table 350 is formed in the HDD 304 that is dedicated to the image forming device 103 and records the reading variation amount (reading characteristics) for each paper.

Figure 13 is a schematic diagram of the reading characteristics table 350. Of these, Figure 13(a) is a diagram showing an overview of the reading characteristics table 350, and Figure 13(b) is a diagram showing an example of the data storage format of the reading characteristics table 350. First, as shown in Figure 13(a), the reading characteristics table 350 stores paper type information for each paper type (first paper type information, second paper type information, etc.) and the reading variation amount information corresponding to that paper type (first reading characteristic, second reading characteristic, etc.), each associated with the other.

As the paper type information, as shown in FIG. 13(b), paper identification information (paper ID) uniquely assigned to the paper type, such as Y0001 or Y0002, and information indicating the paper type, such as plain paper, glossy paper, or matte paper, are stored in the reading characteristics table 350. As the reading variation amount (reading characteristics), as shown in FIG. 13(b), for example, the reading value of an 8-bit read image, such as 255, is stored in the reading characteristics table 350.

When the reading variation acquisition mode is executed again for the same paper type, the paper type information and reading variation information obtained thereby are overwritten in the reading characteristics table 350 (the previous reading variation information is updated with the new reading variation information).

The system may also manage the paper type name or job name, etc., for each paper ID. This allows the reading characteristics table 350 to store the paper ID and the read value of the scanned image, and eliminates the need to store the paper type name or job name, etc., in the reading characteristics table 350.

(Color Fluctuation Correction Operation)
Next, a description will be given of the color variation correction operation of the printing system of the second embodiment, which is performed using such a reading characteristics table 350. Fig. 14 is a functional block diagram of each function realized by the CPU 301 of the image forming apparatus 103 executing a reading variation amount correction program stored in a storage unit such as the HDD 304. Fig. 15 is a flowchart showing the flow of the color variation correction operation performed by the CPU 301 of the image forming apparatus 103 using the reading characteristics table 350 by executing the reading variation amount correction program.

In Fig. 14 and Fig. 15, in step S21, the printer control unit 601 acquires an RIP image of the document to be printed from the DFE 102. In step S22, the printer control unit 601 instructs the image formation control unit 604 to print the RIP image. As a result, in step S23, printing control of the RIP image is performed by the image formation control unit 604.

Next, in step S24, the reference image generating unit 602 obtains from the printer control unit 601 the RIP image and paper type information indicating the type of paper to be used for the upcoming printing. The reference image generating unit 602 then converts the PIP image into a reference image expressed in RGB space, and supplies this, together with the paper type information, to the reading variation correction unit 603a.

Next, in step S25, the print image reading unit 605 reads the print image printed under the control of the image formation control unit 604 and supplies the read image to the reading variation correction unit 603b.

In step S26, the reading characteristic storage control unit 651 acquires the reading variation amount information associated with the paper type information supplied from the reading variation amount correction unit 603a from the reading characteristic table 350 (see Figures 11 to 13). Then, the reading characteristic storage control unit 651 supplies the reading variation amount information associated with the acquired paper type information to the reading variation amount correction unit 603a and the reading variation amount correction unit 603b.

In step S27, the reading variation correction unit 603a generates a corrected reference image by correcting the reading variation of the reference image based on the reading variation information corresponding to the paper type information supplied from the reading characteristics storage control unit 651, and supplies the corrected reference image to the image comparison unit 606. Also in step S27, the reading variation correction unit 603b generates a corrected read image in which the reading variation of the read image is corrected based on the reading variation information corresponding to the paper type information supplied from the reading characteristics storage control unit 651, and supplies the corrected read image to the image comparison unit 606. In step S28, the image comparison unit 606 compares the reference image in which the reading variation has been corrected according to the paper type with the read image in which the reading variation has been corrected according to the paper type to detect color variation.

In step S29, the color variation correction amount generation unit 607 generates a correction amount (color variation correction amount) for the amount of adhered toner. In step S30, the image formation control unit 604 performs color correction processing of the RIP image from the printer control unit 601 based on the color variation correction amount generated by the color variation correction amount generation unit, and then performs printing. This prevents the inconvenience of correcting the variation amount on the image reading side that was not originally superimposed, and makes it possible to print the image by correcting only the variation amount superimposed on the image formation side.

(Effects of the Second Embodiment)
As is clear from the above description, in the printing system of the second embodiment, the amount of reading variation on the read image differs for each image forming device 103 and for each paper type, so the amount of reading variation and paper type information are associated and stored in a storage unit such as the HDD 304. Then, when printing is performed using the same image forming device 103 and the same paper type, the amount of reading variation detected previously is reused. This makes it possible to omit the troublesome task of acquiring the amount of reading variation again when printing again on paper of the same paper type, and also to obtain the same effects as in the first embodiment described above.

[Third embodiment]
Next, a printing system according to a third embodiment will be described. The printing systems according to the above-mentioned embodiments are examples in which an electrophotographic image forming apparatus is provided, but the printing system according to the third embodiment is an example in which an inkjet image forming apparatus is provided. Note that this is the only point that differs between the above-mentioned embodiments and the third embodiment described below. Therefore, hereinafter, only the differences between the two will be described, and duplicated explanations will be omitted.

Figure 16 is a schematic cross-sectional view of an inkjet image forming device provided in the printing system of this third embodiment. As shown in Figure 16, the inkjet image forming device includes a paper feed unit 501, an image forming unit 506, a drying unit 502, and a paper discharge unit 503.

In the image forming device 103, an image is formed on paper P, which is a recording material as a sheet material fed from a paper feed section 501, in an image forming section 506 using ink, which is a liquid for image formation. Then, after the ink adhering to the paper is dried in a drying section 502, the paper is discharged from a paper discharge section 503.

(Paper feed section)
The paper feed section 501 includes a paper feed tray 511 on which a plurality of papers P are stacked, a feed device 512 that separates and sends out the papers P one by one from the paper feed tray 511 , and a pair of registration rollers 513 that sends the papers P to the image forming section 506 .

The feeding device 512 can be any feeding device, such as a device using rollers and rollers, or a device using air suction. After the leading edge of the paper sent out from the paper feed tray 511 by the feeding device 512 reaches the pair of registration rollers 513, the pair of registration rollers 513 are driven at a predetermined timing to feed the paper to the image forming unit 506. There are no limitations on the configuration of the paper feed unit 501, so long as it sends out paper P to the image forming unit 506.

(Image forming section)
The image forming section 506 includes a receiving drum 561 that receives fed paper P, a paper carrying drum 562 that carries the paper P transported by the receiving drum 561 on its outer surface and transports it, an ink ejection section 564 that ejects ink toward the paper P carried on the paper carrying drum 562, and a transfer drum 565 that transfers the paper P transported by the paper carrying drum 562 to the drying section 502.

The paper P transported from the paper feed unit 501 to the image forming unit 506 has its leading edge gripped by a paper gripper provided on the surface of the receiving cylinder 561, and is transported as the surface of the receiving cylinder 561 moves. The paper P transported by the receiving cylinder 561 is handed over to the paper carrying drum 562 at a position opposite the paper carrying drum 562.

A paper gripper is also provided on the surface of the paper carrying drum 562, and the leading edge of the paper is gripped by the paper gripper. In addition, multiple suction holes are formed in a distributed manner on the surface of the paper carrying drum 562, and a suction device 563 generates a suction air current in the direction toward the inside of the paper carrying drum 562 at each suction hole. The leading edge of the paper P transferred from the receiving cylinder 561 to the paper carrying drum 562 is gripped by the paper gripper, and the paper P is adsorbed to the surface of the paper carrying drum 562 by the suction air current, and is transported as the surface of the paper carrying drum 562 moves.

The ink ejection unit 564 ejects four colors of ink, C (cyan), M (magenta), Y (yellow), and K (black), to form an image, and is provided with individual liquid ejection heads 564C, 564M, 564Y, and 564K for each ink. There are no limitations on the configuration of the liquid ejection heads 564C, 564M, 564Y, and 564K, and any configuration may be used as long as they eject liquid. If necessary, liquid ejection heads that eject special inks such as white, gold, and silver inks, or liquid ejection heads that eject liquids that do not form an image, such as surface coating liquids, may be provided.

The liquid ejection heads 564C, 564M, 564Y, and 564K of the ink ejection unit 364 each have an ejection operation controlled by a drive signal corresponding to image information. When the paper P held on the paper carrying drum 562 passes through an area facing the ink ejection unit 564, each color of ink is ejected from the liquid ejection heads 564C, 564M, 564Y, and 564K, and an image corresponding to the image information is formed. Note that there are no limitations on the configuration of the image forming unit 506, so long as it deposits liquid on the paper P to form an image.

(Drying section)
The drying section 502 includes a drying mechanism 521 for drying the ink attached to the paper P in the image forming section 506, and a transport mechanism 522 for transporting the paper P transported from the image forming section 506. The paper P transported from the image forming section 506 is received by the transport mechanism 522, then transported to pass through the drying mechanism 521, and delivered to the paper discharge section 503. When passing through the drying mechanism 521, the ink on the paper P is subjected to a drying process, whereby liquid components such as water in the ink evaporate, the ink is fixed on the paper P, and curling of the paper P is suppressed.

(Paper ejection section)
The paper discharge unit 503 includes a paper discharge tray 531 on which a plurality of sheets of paper P are stacked. The sheets of paper P transported from the drying unit 502 are sequentially stacked and held on the paper discharge tray 531. There are no limitations on the configuration of the paper discharge unit 503 as long as it can discharge the sheets of paper P.

(Other functional parts)
The image forming apparatus 103 includes a paper feed unit 501, an image forming unit 506, a drying unit 502, and a paper discharge unit 503, but other functional units may be added as appropriate. For example, a pre-processing unit that performs pre-processing of the image formation may be added between the paper feed unit 501 and the image forming unit 506. Also, a post-processing unit that performs post-processing of the image formation may be added between the drying unit 502 and the paper discharge unit 503.

Examples of the pre-processing section include a processing liquid application process that applies a processing liquid to the paper P to react with the ink and suppress bleeding, but there are no particular limitations on the content of the pre-processing. Examples of the post-processing section include a paper inversion and transport process that inverts the paper on which an image has been formed in the image forming section 506 and transports it again to the image forming section 506 to form images on both sides of the paper P, a process of binding multiple sheets of paper P on which images have been formed, a correction mechanism that corrects paper deformation, or a cooling mechanism that cools the paper, but there are no particular limitations on the content of the post-processing.

(Effects of the Third Embodiment)
Even when such an inkjet type image forming apparatus is provided, the same effects as those of the above-described embodiments can be obtained.

Finally, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. This novel embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention.

For example, "paper" is not limited to paper, but can include overhead projector film (polyester film), cloth, glass, substrates, etc., and can be anything onto which ink droplets or other liquids can adhere. Also, "paper" includes things called recording media, recording media, recording paper, recording paper, etc. Also, image formation, recording, printing, copying, and printing are all synonymous.

The "inkjet printer device" may form an image by ejecting liquid onto a medium such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc. Furthermore, "image formation" includes not only the formation of images such as characters or figures on a medium, but also the formation of meaningless images such as patterns on a medium (simply causing liquid (droplets) to land on the medium).

In addition, unless otherwise specified, the term "ink" is used as a general term for all liquids that can form images, including but not limited to those called ink, recording liquid, fixing liquid, liquid, etc. For example, "ink" includes DNA (Deoxyribonucleic Acid) samples, resists, pattern materials, resins, etc., as well as water-based latex inks for sign graphics.

In addition, "images" are not limited to flat objects, but also include images formed in a three-dimensional form or three-dimensional objects.

The present invention can also be applied to single-function machines such as printers, facsimile machines, and copiers, or to multifunction machines that incorporate these functions.

In addition, the device for ejecting liquid may be not only a device capable of ejecting liquid onto an object to which the liquid can adhere, but also a device that ejects liquid into air or liquid.

This "liquid ejecting device" may include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as other pre-processing devices and post-processing devices.

In addition, a "liquid ejecting device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves.

In addition, "something to which liquid can adhere" means something to which liquid can adhere at least temporarily, and something to which the liquid adheres and sticks, or something to which the liquid adheres and penetrates. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all things to which liquid can adhere.

Materials that can receive liquid include paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc., as long as the liquid can be attached even temporarily.

The "liquid" is not particularly limited as long as it has a viscosity and surface tension that allows it to be discharged from the head, but it is preferable that the viscosity is 30 mPa·s or less at room temperature and pressure, or by heating or cooling. More specifically, it is a solution, suspension, emulsion, etc. that contains a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural dye, etc. These can be used for applications such as inkjet ink, surface treatment liquid, components of electronic elements or light-emitting elements, and liquids for forming electronic circuit resist patterns.

In addition, the "liquid ejection device" may be a device in which a liquid ejection head and an object to which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which the liquid ejection head moves, and a line type device in which the liquid ejection head does not move.

Other examples of "liquid ejecting devices" include treatment liquid application devices that eject treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and spray granulation devices that spray a composition liquid in which raw materials are dispersed through a nozzle to granulate the raw material into fine particles.

The "liquid ejection head 564" is not limited in the pressure generating means used. For example, in addition to a piezoelectric actuator (which may use a laminated piezoelectric element), it may also be a thermal actuator that uses an electrothermal conversion element such as a heating resistor, or an electrostatic actuator that consists of a vibration plate and an opposing electrode.

In addition, in the present application, the terms image formation, recording, printing, imprinting, printing, modeling, and the like are all synonymous.

The "liquid ejection head 564" is housed in a "liquid ejection unit." This liquid ejection unit is an assembly of components related to the ejection of liquid, in which functional parts and mechanisms are integrated with the liquid ejection head 564. For example, the "liquid ejection unit" includes a combination of at least one of the following components with the liquid ejection head: head tank, carriage, supply mechanism, maintenance and recovery mechanism, and main scanning movement mechanism.

Here, integration includes, for example, the liquid ejection head, functional parts, and mechanism being fixed to each other by fastening, bonding, engagement, etc., and one being held movably relative to the other. The liquid ejection head, functional parts, and mechanism may also be configured to be detachable from each other.

For example, some liquid ejection units have a liquid ejection head and a head tank integrated together. Others have a liquid ejection head and a head tank integrated together by connecting them to each other with a tube or the like. Here, a unit including a filter can be added between the head tank and the liquid ejection head of these liquid ejection units.

There are also liquid ejection units in which the liquid ejection head and carriage are integrated.

In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated. In other liquid ejection units, the liquid ejection head, carriage, and main scanning movement mechanism are integrated.

In some liquid ejection units, a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which the liquid ejection head is attached, integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

In addition, some liquid ejection units have a tube connected to a head tank or a liquid ejection head to which a flow path component is attached, integrating the liquid ejection head with a supply mechanism. Liquid from a liquid storage source is supplied to the liquid ejection head via this tube.

The main scanning movement mechanism includes the guide member alone. The supply mechanism also includes the tube alone and the loading section alone.

Such embodiments and variations of the embodiments are within the scope and spirit of the invention, and are also within the scope of the invention and its equivalents as set forth in the claims.

101 Client personal computer device 102 Digital front end (DFE)
103 Image forming apparatus 104 Management server 301 CPU of image forming apparatus
304 HDD or SSD
306 Image forming unit 307 Reading unit 350 Reading characteristic table 406 In-line sensor 601 Printer control unit 602 Reference image generating unit 603 Reading variation amount generating unit 603a Reading variation amount generating unit 603b Reading variation amount generating unit 604 Image forming control unit 605 Printed image reading unit 606 Image comparison unit 607 Color variation correction amount generating unit 650 Reading characteristic generating unit 651 Reading characteristic storage control unit

Japanese Patent Application Publication No. 11-355636

Claims (8)

an image forming control unit that controls the image forming unit to form an image based on the drawing data;
a reading control unit that controls a reading unit to read the image formed by the image forming control unit;
a read variation amount generating unit that generates a read variation amount of the reference image corresponding to a ratio between a read value of a maximum reference image, which is an image of the drawing data and a read value of the reference image, which is an image of the drawing data;
an added image generating unit that generates an added image by adding the reading variation amount of the reference image to the reference image;
a color variation correction amount generation unit that generates a color variation correction amount used for color variation correction during image formation by subtracting the added image from a read image formed by the image forming unit and read by the reading unit, and supplies the generated color variation correction amount to the image formation control unit;
An image processing device comprising: 2. The image processing device according to claim 1, wherein the read variation generating unit calculates, as the read variation of the reference image, a value obtained by multiplying a ratio between a read value of a maximum reference image, which is an image of a maximum pixel value among the images of the drawing data, and a read value of a reference image, which is an image of the drawing data, by the read variation amount superimposed on the maximum reference image. 3. The image processing device according to claim 1, wherein the read variation generating unit uses a read value of a paper white portion, which is a portion on the paper on which printing based on the drawing data has been performed, as the read value of the maximum reference image. a reference image generating unit that generates a reference image based on drawing data;
a print image reading unit that generates a read image by reading a print image of the drawing data printed on a storage medium by an image forming control unit;
a read variation amount correction unit that acquires read variation amount information corresponding to the type of the storage medium on which the drawing data is printed from a storage unit in which read variation amount information generated based on a read image of a chart image printed on the storage medium is stored for each type of the storage medium, and generates a corrected reference image by correcting the read variation amount of the reference image from the reference image generation unit ;
a color variation correction amount generating unit that compares the corrected reference image with the read image to generate a color variation correction amount used for color variation correction during image formation, and supplies the color variation correction amount to the image formation control unit;
An image processing device comprising: Computer,
an image forming control unit that controls the image forming unit to form an image based on the drawing data;
a reading control unit that controls a reading unit to read the image formed by the image forming control unit;
a read variation amount generating unit that generates an added image by adding a read variation amount of the reference image corresponding to a ratio between a read value of a maximum reference image, which is an image of the drawing data, and a read value of the reference image, which is an image of the drawing data; and
an image processing program that functions as a color variation correction amount generation unit that generates a color variation correction amount used for color variation correction during image formation and supplies the color variation correction amount to the image formation control unit by subtracting the added image from the read image formed by the image forming unit and read by the reading unit. Computer,
a reference image generating unit that generates a reference image based on drawing data;
a print image reading unit that generates a read image by reading a print image of the drawing data printed on a storage medium by an image forming control unit;
a read variation amount correction unit that acquires read variation amount information corresponding to the type of the storage medium on which the drawing data is printed from a storage unit in which read variation amount information generated based on a read image of a chart image printed on the storage medium is stored for each type of the storage medium, and generates a corrected reference image by correcting the read variation amount of the reference image from the reference image generation unit ;
and functioning as a color variation correction amount generation unit that compares the corrected reference image and the read image, generates a color variation correction amount used for color variation correction during image formation, and supplies the color variation correction amount to the image formation control unit. an image forming unit that forms an image;
an image forming control unit that controls the image forming unit so as to form an image corresponding to drawing data;
a reading control unit that controls a reading unit to read the image formed by the image forming control unit;
a read variation amount generating unit that generates an added image by adding a read variation amount of the reference image corresponding to a ratio between a read value of a maximum reference image, which is an image of the drawing data, and a read value of the reference image, which is an image of the drawing data; and
a color variation correction amount generation unit that generates a color variation correction amount used for color variation correction during image formation by subtracting the added image from a read image formed by the image forming unit and read by the reading unit, and supplies the generated color variation correction amount to the image formation control unit;
An image forming apparatus comprising: an image forming unit that forms an image;
a reference image generating unit that controls the image forming unit to generate a reference image based on drawing data;
a print image reading unit that generates a read image by reading a print image of the drawing data printed on a storage medium by an image forming control unit that controls the image forming unit;
a read variation amount correction unit that acquires read variation amount information corresponding to the type of the storage medium on which the drawing data is printed from a storage unit in which read variation amount information generated based on a read image of a chart image printed on the storage medium is stored for each type of the storage medium, and generates a corrected reference image by correcting the read variation amount of the reference image from the reference image generation unit ;
a color variation correction amount generating unit that compares the corrected reference image with the read image to generate a color variation correction amount used for color variation correction during image formation, and supplies the color variation correction amount to the image formation control unit;
An image forming apparatus comprising:

Images