JP2023062309A - Image forming apparatus, image forming system, and image forming method - Google Patents

Abstract

To provide an image forming apparatus, an image forming system, and an image forming method with which highly accurate density correction and tone correction can be simultaneously achieved by using information acquired by an in-line sensor mounted inside an image forming unit.SOLUTION: An image forming apparatus comprises: a read image processing unit that, when performing tone correction processing, converts information on a pattern for tone correction read by an in-line sensor into density values; a maximum density control unit that, on the basis of, the maximum density value of the density values and a target maximum density value, calculates a correction amount for the maximum density value, and according to the correction amount, changes maximum density settings included in paper settings for which correction is executed; and a paper maximum density setting control unit that, after the change of the maximum density settings, updates the maximum density settings included in the paper settings. After the update of the maximum density settings, an image correction processing control unit executes both density correction and tone correction for an image forming unit again by using the pattern for tone correction.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus, an image forming system, and an image forming method.

In the digital equipment used in the commercial printing business, there is a growing movement toward automating each function. Color matching (color correction technology), which is important in digital devices, is also being automated so as not to bother the user. In order to achieve automation of color matching in digital equipment, it is necessary to stabilize density and perform color correction using sensor information installed in the digital equipment.

In Patent Document 1, for the purpose of adjusting the maximum density value of an image forming apparatus such as a printer to a target maximum density value, the contrast voltage of the printer is adjusted until the target maximum density value is obtained, and then calibration is performed. Techniques for performing tone correction have been disclosed.

However, with high-precision color correction technology, it is essential to print a chart to adjust the maximum density value each time. No consideration is given to page-to-page unevenness of the maximum density value chart.

In the technique of Patent Document 1, chart printing for adjusting the maximum density value is essential in order to perform highly accurate calibration color correction, and a chart for maximum density adjustment different from the chart for calibration correction is printed. Requires multiple prints. Further, in the technique of Patent Document 1, the target value of the maximum density value, the set value of the maximum density value, the calibration data, and the paper information are not linked, and it is necessary to print a chart for adjusting the maximum density each time. . Furthermore, when obtaining the maximum density value, density unevenness within a page is considered, but inter-page unevenness of the maximum density value is not considered.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an image forming apparatus capable of simultaneously performing highly accurate density correction and gradation correction using information obtained by an in-line sensor mounted inside an image forming unit. An object of the present invention is to provide a forming apparatus, an image forming system, and an image forming method.

In order to solve the above-described problems and achieve the object, the present invention provides an image forming section, an in-line sensor mounted inside the image forming section, and a gradation correcting sensor that controls the image forming section. An image formation control unit for forming an image of a pattern, an image correction processing control unit for performing both density correction and gradation correction of the image forming unit using the gradation correction pattern, and the in-line sensor. a reading control unit for reading the gradation correction pattern; a read image processing unit for converting information read from the gradation correction pattern by the in-line sensor into a density value when the gradation correction process is performed; A correction amount for the maximum density value is calculated based on the maximum density value and the target maximum density value among the density values, and the maximum density setting included in the paper settings to be corrected is changed according to the correction amount. a density control unit; and a maximum paper density setting control unit for updating the maximum density setting included in the paper setting after changing the maximum density setting, wherein the image correction processing control unit updates the maximum density setting. Thereafter, both the density correction and the gradation correction of the image forming section are executed again using the gradation correction pattern.

According to the present invention, it is possible to achieve high-precision density correction and gradation correction at the same time using information acquired by an in-line sensor mounted inside an image forming section.

FIG. 1 is a diagram showing an example of the configuration of an image forming system according to this embodiment. FIG. 2 is a block diagram showing an example of the hardware configuration of the DFE according to this embodiment. FIG. 3 is a diagram showing an example of the hardware configuration of the image forming apparatus according to this embodiment. FIG. 4 is a diagram showing an example of the functional configuration of the DFE and the image forming apparatus according to this embodiment. FIG. 5 is a flowchart showing an example of the flow of maximum density value adjustment processing and automatic calibration executed in the image forming system according to the present embodiment. FIG. 6 is a diagram showing an example of a chart for automatic calibration printed when automatic calibration of the image forming apparatus according to the present embodiment is performed. FIG. 7 is a diagram for explaining an example of a display screen including results of performing automatic calibration and obtaining results of maximum density values in the image forming system according to the present embodiment. FIG. 8 is a diagram for explaining another example of the display screen including the result of automatic calibration and the result of obtaining the maximum density value in the image forming system according to the present embodiment. FIG. 9 is a diagram for explaining an example of the relationship between maximum density setting, target maximum density value, and read information (maximum density value) in the image forming system according to the present embodiment.

Exemplary embodiments of an image forming apparatus, an image forming system, and an image forming method will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram showing an example of the configuration of an image forming system according to this embodiment. The image forming system 1 according to the present embodiment has a client PC (Personal Computer) 101, a DFE (Digital Front End) 102, an image forming apparatus 103, and a management server 104, as shown in FIG.

The client PC 101 creates a print job that the user wants to print, and transmits the print job to the DFE 102 or management server 104 . The client PC 101 includes a display unit such as a liquid crystal display, an input device including a mouse and a keyboard.

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

The image forming apparatus 103 forms an image based on the drawing data received from the DFE 102 . Further, the image forming apparatus 103 reads an image using an in-line sensor mounted inside the image forming apparatus 103 when a reading instruction is given.

The management server 104 manages print jobs received from the client PC 101 . Also, the management server 104 transmits a print job to the DFE 102 in response to a request from the DFE 102 .

FIG. 2 is a block diagram showing an example of the hardware configuration of the DFE according to this embodiment. As shown in FIG. 2, the DFE 102 according to the present embodiment includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, an HDD (Hard Disk Drive)/SSD (Solid State Drive) 204 and I/F 205 .

The CPU 201 uses the RAM 203 as a work area and executes programs stored in the ROM 202 . The HDD/SSD 204 is used as a storage unit and stores preset setting values. Information stored in the HDD/SSD 204 may be used by the CPU 201 when executing a read program. An I/F 205 is an interface that enables communication between the DFE 102, the client PC 101, the image forming apparatus 103, and the management server 104. FIG.

FIG. 3 is a diagram showing an example of the hardware configuration of the image forming apparatus according to this embodiment. The image forming apparatus 103 according to this embodiment has a CPU 301, a ROM 302, a RAM 303, an HDD/SSD 304, an I/F 305, an image forming section 306, and a reading section 307, as shown in FIG.

The CPU 301 uses the RAM 303 as a work area and executes programs stored in the ROM 302 to control the overall operation of the image forming apparatus 103 . The HDD/SSD 304 is used as a storage unit and stores preset setting values. Information stored in the HDD/SSD 304 may be used by the CPU 301 when executing the read program.

The I/F 305 is an interface that enables communication between the image forming apparatus 103, the DFE 102, the client PC 101, and the management server 104. FIG. An image forming unit 306 is a print engine that forms a print image on a print sheet (an example of a recording medium). A reading unit 307 is a reading device (an example of an in-line sensor) that reads a print image formed on printing paper, and is mounted inside the image forming unit 206 . The paper supply unit 500 is an example of a supply unit capable of supplying printing paper to the image forming unit 306 .

FIG. 4 is a diagram showing an example of the functional configuration of the DFE and the image forming apparatus according to this embodiment. The DFE 102 according to this embodiment has an image processing unit 401, a maximum density control unit 402, an image correction processing control unit 403, a maximum paper density setting control unit 404, and a read image processing unit 408, as shown in FIG. .

The image processing unit 401 performs start notification when starting an image processing function and image processing when executing a print job.

The maximum density control unit 402 is a control unit that calculates information about the maximum density value and determines whether to change the calculated maximum density value when the image forming system 1 is executed. Specifically, the maximum density control unit 402 determines the correction amount of the maximum density value based on the maximum density value and the target maximum density value among the density values converted from the patch information by the read image processing unit 408, which will be described later. calculate. Next, the maximum density control unit 402 changes the maximum density setting included in the paper setting to be corrected according to the calculated correction amount.

Then, when the maximum density setting is changed, the maximum density control unit 402 notifies the maximum paper density setting control unit 404 of the maximum density setting. Thus, the color information (patch information) obtained by reading the gradation correction pattern is used to calculate the data necessary for correcting the maximum density value, and the gradation correction pattern is used to perform density correction and gradation correction. can be implemented. As a result, using the patch information acquired by the reading unit 307 mounted inside the image forming unit 306, highly accurate density correction and gradation correction can be realized at the same time.

The image correction processing control unit 403 creates a gradation correction curve for performing color correction such as gradation correction based on target values and colorimetric values (data of the read image processing unit 408) for performing color correction processing. , etc., and applies the calculated correction curve to the print job. Specifically, the image correction processing control unit 403 performs both density correction and tone correction of the image forming unit 306 using the tone correction pattern. After updating the maximum density setting included in the paper setting by the maximum paper density setting control unit 404 (to be described later), the image correction processing control unit 403 again uses the gradation correction pattern to correct the density of the image forming unit 306 and Perform both tonal corrections.

The image correction processing control unit 403 also includes a storage unit that stores gradation correction target values and gradation correction data (gradation correction curves) for each recording medium such as paper for special colors in addition to process colors. Further, in the present embodiment, when the color used in the image forming unit 306 is switched to a special color, the image correction processing control unit 403 sets the gradation correction data corresponding to the special color to the special color to be used for gradation correction. A toner determination control unit is provided.

A maximum paper density setting control unit 404 is a control unit that stores paper settings and changes and saves the paper settings. Further, when the maximum density setting is changed, the maximum paper density setting control unit 404 saves the changed maximum density setting in the paper setting. That is, the maximum paper density setting control unit 404 updates the maximum density setting included in the paper setting after the maximum density setting is changed. Further, the maximum paper density setting control unit 404 associates and manages (for example, stores) the maximum density target value, maximum density setting, tone correction data, and recording medium such as paper.

A read image processing unit 408 converts patch information read by a read control unit 406, which will be described later, into density values, and performs data processing that can be used for determination and color correction processing. Specifically, when performing tone correction processing, the read image processing unit 408 converts patch information (an example of read information) of the pattern for tone correction by the reading unit 307 into a density value.

The image forming apparatus 103 according to this embodiment has an image formation control unit 405, a read control unit 406, and a read image acquisition unit 407, as shown in FIG.

The image formation control unit 405 is a control unit that forms images of print jobs and charts. Specifically, the image formation control unit 405 performs image formation using the maximum density setting included in the paper settings.

When performing automatic calibration, the reading control unit 406 controls the reading unit 307 while the printing paper is being conveyed, and reads an image-formed automatic calibration chart (an example of a gradation correction pattern).

A read image acquisition unit 407 acquires patch information while the printing paper is being conveyed. Here, the patch information is patch information included in the automatic calibration chart read by the reading unit 307 . Also, the patch information is used for color correction processing. Therefore, the read image acquisition unit 407 collectively stores the patch information and transfers the patch information to the read image processing unit 408 .

In the present embodiment, the DFE 102 and the image forming apparatus 103 cooperate to function as an example of the image forming apparatus, but the present invention is not limited to this, and only the image forming apparatus 103 functions as an example of the image forming apparatus. It is also possible to

FIG. 5 is a flowchart showing an example of the flow of maximum density value adjustment processing and automatic calibration executed in the image forming system according to the present embodiment.

When automatic calibration is instructed in order to perform color correction processing of the image forming apparatus 103, the image forming control unit 405 of the image forming apparatus 103 controls the image forming unit 306 to perform calibration on printing paper. Then, an automatic calibration pattern including a chart for automatic calibration is printed (image formation) (step S501).

When performing automatic calibration, the reading control unit 406 of the image forming apparatus 103 controls the reading unit 307 mounted inside the image forming apparatus 103 to read the image output pattern being printed (chart for automatic calibration). ) is read (step S502). Next, the read image acquisition unit 407 of the image forming apparatus 103 acquires patch information of the read image output pattern while the printing paper is being conveyed. Further, the read image acquisition unit 407 converts the acquired patch information (sensor information) into density values (step S503).

Next, the maximum density control unit 402 of the DFE 102 determines whether or not to adjust the maximum density value based on the difference information between the converted density value and the target maximum density value (step S504). If the maximum density value among the converted density values has reached the target maximum density value, the maximum density control unit 402 determines that adjustment of the target maximum density value is unnecessary (step S504: No).

In this case, the image correction processing control unit 403 of the DFE 102 generates a gradation correction curve, which is a correction curve for gradation correction, based on the patch information obtained by reading the image output pattern (step S505). Further, the image correction processing control unit 403 applies the generated gradation correction curve to the print job (step S506). After that, the image forming control unit 405 of the image forming apparatus 103 performs image output (printing) of the print image on the print paper according to the print job (step S507).

On the other hand, if the maximum density value among the converted density values has not reached the target maximum density value, the maximum density control unit 402 of the DFE 102 determines that the target maximum density value needs to be adjusted (step S504: Yes). In this case, the maximum density control unit 402 calculates the maximum density value correction amount for achieving the target maximum density value based on the maximum density value and the target maximum density value (step S508). Furthermore, the maximum density control unit 402 changes the maximum density value according to the calculated correction amount (step S509). Thereafter, the maximum paper density setting control unit 404 of the DFE 102 saves the maximum density setting corresponding to the changed maximum density value in the paper settings (step S510).

FIG. 6 is a diagram showing an example of a chart for automatic calibration printed when automatic calibration of the image forming apparatus according to the present embodiment is performed. In the present embodiment, as shown in FIG. 6, the chart for automatic calibration is such that patches (for example, patches C1 and M1) of the engine solid density (maximum density value) of toner of each color are aligned within the plane of the printing paper. It is a sparsely spaced and multi-page printed chart. As a result, it is possible to provide a chart capable of correcting unevenness in density values within the plane of the printing paper and unevenness in density values between pages.

In addition, by including the maximum density value patch in the chart for automatic calibration, there is no need to print a chart for adjusting the maximum density value separately from the chart for automatic calibration. can be used to obtain the maximum density value. In addition, it is possible to accurately correct the maximum density value in consideration of the unevenness of the density value within the surface of the printing paper in the image forming apparatus 103 and the unevenness of the density value between pages.

FIG. 7 is a diagram for explaining an example of a display screen including results of performing automatic calibration and obtaining results of maximum density values in the image forming system according to the present embodiment. In this embodiment, the chart for automatic calibration includes a plurality of patches for gradation correction in addition to the maximum density value patch. Therefore, the read image acquisition unit 407 of the image forming apparatus 103 acquires the patch information of the tone correction patch in addition to the patch information of the patch with the maximum density value. Therefore, according to the image forming system of this embodiment, a graph showing the relationship between the density value (measured value) converted from the patch information and the relative value (%) of the target density value can be obtained.

Therefore, in the present embodiment, the client PC 101 displays a target maximum density value, a density value (measured value), a notch setting (maximum density setting) and a determination item as to whether the maximum density value satisfies the target maximum density value.

Further, when there is a color plate (for example, black K) whose maximum density value does not satisfy the target maximum density value, the client PC 101 may include a message to the effect that the target maximum density value is not satisfied on the display screen. good. Furthermore, the client PC 101 may include a re-execution button for instructing re-execution of automatic calibration on the display screen. When the client PC 101 presses a rerun button included in the display screen, the image forming apparatus 103 prints the chart for automatic calibration with the updated maximum density setting. The user can instruct re-execution of the adjustment of the maximum density value by pressing a re-execution button.

FIG. 8 is a diagram for explaining another example of the display screen including the result of automatic calibration and the result of obtaining the maximum density value in the image forming system according to the present embodiment. If there is a color plate (for example, black K) whose maximum density value does not satisfy the target maximum density value, and automatic calibration is re-executed, and the maximum density value satisfies the target maximum density value for all color plates, the client The PC 101 displays a display screen including a determination item indicating that the maximum density values of all color plates satisfy the target maximum density value. In this case, since there is no need to re-execute the automatic calibration, the client PC 101 displays the re-execution button on the display screen in such a state that it cannot be pressed.

FIG. 9 is a diagram for explaining an example of the relationship between maximum density setting, target maximum density value, and read information (maximum density value) in the image forming system according to the present embodiment. The paper settings include maximum density settings for adjusting the maximum density value when the image forming apparatus 103 prints a print image. If the maximum density value of the print image printed according to the paper settings used for printing does not reach the target maximum density value, the maximum density control unit 402 of the DFE 102 changes the maximum density setting included in the paper settings to perform image formation. It is possible to increase or decrease the maximum density value when the print image is output by the device 103 .

Specifically, the maximum density control unit 402 of the DFE 102 determines the target maximum density value and the maximum density value for the color plate that needs to satisfy the target maximum density value based on the target maximum density value and the maximum density value. Difference information is calculated, and the maximum density setting included in the paper settings is updated based on the difference information. By updating the maximum density setting included in the paper settings, it is possible to perform automatic calibration in a state in which the target maximum density value is satisfied when correcting the maximum density value from the next time onwards. In addition, even if the maximum density value changes due to aging, it is possible to notice that the maximum density value has changed during automatic calibration, and automatic calibration can be performed with the optimum maximum density value. can be implemented.

As described above, according to the image forming system 1 according to the present embodiment, the color information (patch information) obtained by reading the gradation correction pattern is used to calculate the data necessary for correcting the maximum density value. Density correction and tone correction can be performed using the tone correction pattern. As a result, using the patch information acquired by the reading unit 307 mounted inside the image forming unit 306, highly accurate density correction and gradation correction can be realized at the same time.

In the above embodiment, an example in which the image forming apparatus of the present invention is applied to a multifunctional machine having at least two functions out of a copy function, a printer function, a scanner function and a facsimile function will be described. , printers, scanners, facsimile machines, and other image forming apparatuses.

101 Client PC
102 DFEs
103 image forming apparatus 104 management server 401 image processing unit 402 maximum density control unit 403 image correction processing control unit 404 maximum paper density setting control unit 405 image formation control unit 406 reading control unit 407 read image acquisition unit 408 read image processing unit

Japanese Patent No. 3885058

Claims (6)

an image forming unit;
an in-line sensor mounted inside the image forming unit;
an image forming control unit that controls the image forming unit to form an image of a gradation correction pattern;
an image correction processing control unit that performs both density correction and gradation correction of the image forming unit using the gradation correction pattern;
a reading control unit that controls the inline sensor to read the gradation correction pattern;
a read image processing unit for converting read information of the gradation correction pattern read by the in-line sensor into a density value when performing gradation correction processing;
A correction amount for the maximum density value is calculated based on the maximum density value and the target maximum density value among the density values, and the maximum density setting included in the paper setting to be corrected is changed according to the correction amount. a maximum concentration control unit;
a maximum paper density setting control unit for updating the maximum density setting included in the paper setting after changing the maximum density setting;
The image forming apparatus, wherein the image correction processing control section executes both density correction and tone correction of the image forming section again using the tone correction pattern after updating the maximum density setting. 2. The image forming apparatus according to claim 1, wherein the gradation correction pattern is a pattern in which the patches having the maximum density values are sparsely arranged within a plane of the recording medium and printed on a plurality of recording mediums. 3. The maximum paper density setting control unit according to claim 1, wherein the target value of maximum density of the image forming unit, the maximum density setting, the gradation correction data, and the recording medium are linked and managed. Image forming device. The image correction processing control unit,
a storage unit that stores gradation correction target values and gradation correction data for each recording medium for special colors in addition to process colors;
a special color toner determination control unit that uses the gradation correction data corresponding to the special color for gradation correction when the color used in the image forming unit is switched to the special color;
The image forming apparatus according to any one of claims 1 to 3, comprising: an image forming unit;
an in-line sensor mounted inside the image forming unit;
an image forming control unit that controls the image forming unit to form an image of a gradation correction pattern;
an image correction processing control unit that performs both density correction and gradation correction of the image forming unit using the gradation correction pattern;
a reading control unit that controls the inline sensor to read the gradation correction pattern;
a read image processing unit for converting read information of the gradation correction pattern read by the in-line sensor into a density value when performing gradation correction processing;
A correction amount for the maximum density value is calculated based on the maximum density value and the target maximum density value among the density values, and the maximum density setting included in the paper setting to be corrected is changed according to the correction amount. a maximum concentration control unit;
a maximum paper density setting control unit for updating the maximum density setting included in the paper setting after changing the maximum density setting;
The image forming system, wherein the image correction processing control unit uses the tone correction pattern again to execute both the density correction and the tone correction of the image forming unit after updating the maximum density setting. An image forming method performed by an image forming apparatus comprising an image forming unit and an in-line sensor mounted inside the image forming unit,
an image forming control unit controlling the image forming unit to form an image of the gradation correction pattern;
an image correction processing control unit performing both density correction and tone correction of the image forming unit using the tone correction pattern;
a reading control unit reading the gradation correction pattern by controlling an in-line sensor mounted inside the image forming unit;
a step of converting the readout information of the pattern for tone correction by the in-line sensor into a density value when the image-reading processing unit performs the tone correction process;
A maximum density control unit calculates a correction amount for the maximum density value based on a maximum density value and a target maximum density value among the density values, and includes sheet settings for performing correction according to the correction amount. changing the maximum density setting;
a step of a maximum paper density setting control unit updating the maximum density setting included in the paper setting after changing the maximum density setting;
a step in which the image correction processing control unit performs both density correction and gradation correction of the image forming unit again using the gradation correction pattern after updating the maximum density setting;
An imaging method comprising:

Images