Image forming apparatus, image forming method, and program

Abstract

The present invention provides an image forming apparatus, an image forming method, and a program that can detect cases where readjustment is necessary even after selecting the optimal amount of deposition to achieve the target color value, and can automatically proceed to readjustment. [Solution] The present invention comprises a target value acquisition means for acquiring a target color value, a sensor value acquisition means for acquiring the color value of a printed material with an internal sensor, and an adjustment means for changing the amount of toner to adhere to the printed material based on the difference between the target color value and the color value acquired by the sensor, wherein the adjustment means includes an update means for pre-holding a relationship formula between the amount of toner to adhere and the color value, and updating the relationship formula using the acquired color value.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, an image forming method, and a program.

Background Art

[0002] In a printing machine, it is difficult to adjust the transfer of a toner image. To obtain a desired image density, a large number of man-hours are required, resulting in a large burden on the operator and an increase in cost. In contrast, Patent Document 1 states that the burden on the operator can be significantly reduced by providing a system that automatically selects an optimal transfer voltage (adhesion amount) and can easily perform fine adjustments according to the user's preferences.

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, in the technique described in Patent Document 1, as a result of selecting an optimal transfer voltage, the corresponding density is not necessarily obtained, and there are cases where readjustment is required even after selecting the optimal transfer voltage. Patent Document 1 does not mention a configuration for automatically readjusting the transfer voltage in cases where readjustment is required.

[0004] The present invention has been made in view of the above, and an object thereof is to provide an image forming apparatus, an image forming method, and a program that can detect a case where readjustment is required even when selecting an optimal adhesion amount for obtaining a target color value and can automatically proceed to readjustment. [[ID=XX]]

Means for Solving the Problems

[0005] To solve the above-mentioned problems and achieve the objective, the present invention comprises: a target value acquisition means for acquiring a target color value; a sensor value acquisition means for acquiring the color value of a printed material using an internal sensor; and an adjustment means for changing the amount of toner to adhere to the printed material based on the difference between the target color value and the color value acquired by the sensor, wherein the adjustment means includes an update means for pre-holding a relationship formula between the amount of toner to adhere and the color value, and updating the relationship formula using the acquired color value. [Effects of the Invention]

[0006] According to the present invention, even when the optimal amount of coating to achieve the target color value is selected, the system can detect cases where readjustment is necessary and automatically proceed to readjustment. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of the system configuration of an image forming system including the image forming apparatus according to this embodiment. [Figure 2] Figure 2 shows an example of the hardware configuration of the image forming system according to this embodiment. [Figure 3] Figure 3 shows an example of the detailed configuration of the sensor in the image forming system according to this embodiment. [Figure 4-1] Figure 4-1 is a diagram illustrating an example of the mechanism for adjusting the target density in the image forming system according to this embodiment. [Figure 4-2] Figure 4-2 is a diagram illustrating an example of the mechanism for adjusting the target density in the image forming system according to this embodiment. [Figure 5-1] Figure 5-1 is a flowchart showing an example of the flow of initial adjustment to the highest density in the image forming system according to this embodiment. [Figure 5-2] Figure 5-2 is a flowchart showing an example of the flow of automatic adjustment of the maximum density in the image forming system according to this embodiment. [Figure 6]Figure 6 shows an example of the functional configuration of the control unit of the image forming system according to this embodiment. [Figure 7] Figure 7 is a flowchart showing an example of a detailed flow of automatic adjustment of the maximum density in the image forming system according to this embodiment. [Figure 8] Figure 8 is a flowchart showing an example of the flow of the process for calculating the amount of adhesion in the image forming system according to this embodiment. [Figure 9] Figure 9 is a diagram illustrating an example of the adhesion amount adjustment process in the image forming system according to this embodiment. [Figure 10] Figure 10 is a diagram illustrating an example of the process for adjusting the amount of adhesion in the image forming system according to the embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the image forming apparatus, image forming method, and program will be described in detail below with reference to the attached drawings.

[0009] Figure 1 shows an example of the system configuration of an image forming system including the image forming apparatus according to this embodiment. Figure 2 shows an example of the hardware configuration of the image forming system according to this embodiment. In this embodiment, the image forming apparatus 100 can receive print jobs from a PC (Personal Computer) via a network. The image forming apparatus 100 also has printing and copying functions as a digital color multifunction device.

[0010] The image forming apparatus 100 includes components such as a paper feeding unit 105, a transport unit 107, a control unit 101, a communication unit 110, an operation display unit 120, a scanner unit 130, and a printer unit 150. The image forming apparatus 100 is also connected to an intermediate device 200 and a post-processing device 300.

[0011] The communication unit 110 includes a communication control unit 111 and a communication I / F unit 112. The operation display unit 120 has an operation display control unit 121, an operation unit 122, and a display unit 123, and realizes various operation screens and information display functions. The scanner unit 130 has a scanner control unit 131 and a line image sensor 132, and realizes document reading function and image data generation function.

[0012] The printer unit 150 comprises a printer control unit 151 and a print engine 152, and realizes the image formation function. Specifically, the printer unit 150 forms an electrostatic latent image by exposure to a photoreceptor and transfers the image to paper with toner. The control unit 101 oversees the operation of the entire image forming apparatus 100 and consists of an image control CPU 1011, a DRAM (Dynamic Random Access Memory) control unit 1012, a storage unit 1013, an HDD (Hard Disk Drive) 1014, an image memory 1015, a read processing unit 1017, a write processing unit 1018, etc. The storage unit 1013 includes a ROM (Read Only Memory) 1013a, a RAM (Random Access Memory) 1013b, a non-volatile memory 1013c, etc.

[0013] Various data are stored in the non-volatile memory 1013c. Each control unit consists of a circuit including a CPU, ROM, and RAM. The printer unit 150 employs an electrophotographic method and is capable of monochrome and color printing.

[0014] The intermediate device 200 includes an intermediate processing control unit 201, an inversion unit 210, and a density sensor 220. The post-processing device 300 is a device equipped with various post-processing functions, such as folding recording paper, bundling multiple recording papers together and stapling them, and punching holes in them. The post-processing device 300 is configured to include a post-processing control unit 301 that controls each part of the post-processing device 300, a post-processing unit 310 that performs various post-processing, and an output unit 390 that ejects the paper. The post-processing control unit 301 controls the operation of the post-processing device 300 under the control of the control unit 101 by communicating with the control unit 101.

[0015] FIG. 3 is a diagram showing an example of the detailed configuration of a sensor included in the image forming system according to the present embodiment. In the present embodiment, the printer unit 150 includes a density sensor 220. The density sensor 220 irradiates light of a predetermined wavelength from a light emitting element 221 onto the sheet P being conveyed, receives the reflected light with a light receiving element 222, and detects color values (for example, toner density, RGB values) on the sheet P. When corresponding to a color image, the light emitting element 221 and the light receiving element 222 are configured to detect color values such as toner density and RGB values on the sheet P using light of wavelengths corresponding to each color toner.

[0016] FIGS. 4-1 and 4-2 are diagrams for explaining an example of the mechanism for adjusting the target density in the image forming system according to the present embodiment. In the present embodiment, as shown in FIG. 4-1, the nonvolatile memory 1013c included in the storage unit 1013 stores a paper profile 1013p, an adhesion amount adjustment value 1013d1, and the like. The paper profile 1013p is associated with the paper feeding unit 105 and recorded in the nonvolatile memory 1013c.

[0017] Each paper profile has a different identification number (for example, #1 to #500) and is recognized by the control unit 101. The paper profile includes setting information such as the type, name, basis weight, color, thickness, toner adhesion amount offset value, etc. of the paper. A specific number (for example, #500) is reserved as a target density corresponding paper profile and used for the highest density automatic adjustment at the time of new.

[0018] As shown in FIGS. 4-1(a) to (c), the image forming apparatus 100 performs two types of density adjustments: new highest density automatic adjustment and highest density automatic adjustment. The new highest density automatic adjustment corrects the characteristics of the process unit at the time of installation of the image forming apparatus 100 by performing process control (automatically adjusting the highest density from the toner amount on the belt using the P sensor), printing at the adjusted highest density, and registering the value read by the density sensor 220 for the RGB values on the printed paper as the highest density. The highest density automatic adjustment is performed by the printer unit 150 at the start of use of the image forming apparatus 100, detects the toner density of the density patch, and adjusts the highest density to match the target density 1013d2 (an example of the target color value). The adjustment value (adhesion amount adjustment value 1013d1) is a value used to control the highest density in the printer unit 150.

[0019] In the present embodiment, as shown in FIGS. 4-2(b) and (c), the nonvolatile memory 1013c included in the storage unit 1013 may store the target density 1013d2 (for example, the solid RGB value) in the ID (calibration ID) used for print color adjustment. Also, in the present embodiment, as shown in FIG. 4-2, in addition to the target density 1013d2, the paper type, date, calibration result, and adhesion amount adjustment value 1013d1 may be stored in the calibration ID.

[0020] FIG. 5-1 is a flowchart showing an example of the flow of the new highest density automatic adjustment in the image forming system according to the present embodiment. FIG. 5-2 is a flowchart showing an example of the flow of the highest density automatic adjustment in the image forming system according to the present embodiment. The new highest density automatic adjustment may take a pre-installed configuration at the time of process shipment for each paper type.

[0021] First, the control unit 101 adjusts the maximum density using process control (step S11). Specifically, the control unit 101 adjusts the maximum density of the print using process control. Here, the image forming apparatus 100 sets appropriate parameters to achieve the target density by reading the toner on the fuser belt with the P sensor. Next, the control unit 101 prints a maximum density adjustment chart (step S12). Specifically, the control unit 101 prints a dedicated chart, the maximum density adjustment chart, with the adjusted maximum density. Next, the control unit 101 acquires the current solid RGB values ​​with the line image sensor 132 (step S13). Specifically, the control unit 101 scans the printed maximum density adjustment chart with the line image sensor 132 to acquire the current solid RGB values. The RGB values ​​acquired at this stage are used as target values ​​for automatic maximum density adjustment during updates.

[0022] Next, the control unit 101 saves the current RGB value of the solid fill as the target RGB value of the solid fill (target value) to a storage device such as the non-volatile memory 1013c (step S14). By saving the target value to the storage device, the scanning can be started from the amount of coating at that time when it is updated, thus improving efficiency. Alternatively, the target value may be saved in the process that calls the maximum density automatic adjustment, rather than in step S14.

[0023] During automatic maximum density adjustment upon update, the control unit 101 reads the paper settings and target density of the paper used in the initial automatic maximum density adjustment from the non-volatile memory 1013c (step S1). Next, the control unit 101 outputs a calibration chart and detects the toner density with the density sensor 220 (step S2). Then, the control unit 101 adjusts the maximum density so that the density detection result on the calibration chart matches the target density (step S3).

[0024] Figure 6 shows an example of the functional configuration of the control unit 101 of the image forming system according to this embodiment. In this embodiment, the control unit 101 includes a target value acquisition unit 101a, a sensor value acquisition unit 101b, an adjustment unit 101c, etc., as shown in Figure 6.

[0025] The target value acquisition unit 101a is an example of a target value acquisition means for acquiring target color values ​​such as target density. The target value acquisition unit 101a may also function as an example of a color value storage means for storing multiple target color values ​​from the initial print run as different paper profiles for each type of paper. The target value acquisition unit 101a may also set the target color values ​​by applying a paper profile corresponding to the selected type of paper. This allows the image forming apparatus 100 to save a paper profile for each type of paper, and the user can easily save paper profiles for multiple paper types or thicknesses at any time.

[0026] The sensor value acquisition unit 101b is an example of a sensor value acquisition means that acquires toner density and color values ​​such as RGB values ​​of printed materials such as paper on which an image has been transferred using a density sensor 220 (an example of an internal sensor).

[0027] The adjustment unit 101c is an example of an adjustment means that changes the amount of toner deposited on the printed material based on the difference between the target color value acquired by the target value acquisition unit 101a and the color value acquired by the density sensor 220. The adjustment unit 101c also stores a relationship formula between the amount of toner deposited and the color value in advance. The adjustment unit 101c then functions as an example of an update means that updates this relationship formula using the color value acquired by the sensor value acquisition unit 101b. As a result, the relationship between the current amount of toner deposited and the color value can be grasped each time the amount of toner deposited is adjusted, and as a result the accuracy of the toner deposition adjustment can be improved.

[0028] Furthermore, the adjustment unit 101c functions as an example of a correction means that corrects the relational expression each time the sensor value acquisition unit 101b acquires a color value. In this case, the adjustment unit 101c modifies the relational expression to minimize the error between each color value and the relational expression. This allows the relational expression to be updated each time a color value is measured, and the current relationship between the amount of adhesion and the color value can be obtained.

[0029] Furthermore, the adjustment unit 101c reduces or maintains the amount of adhesion based on the difference between the target color value and the color value acquired by the sensor value acquisition unit 101b, and the number of updates to the relational expression. This reduces the impact of incorrect estimation of the optimal adhesion amount when variations in the image forming apparatus 100 occur when the color value is close to the target color value.

[0030] Furthermore, the adjustment unit 101c may identify the type of paper based on at least one of the paper weight and texture, or by using a color value measurement sensor or a paper type identification sensor, and select the optimal initial value for the amount of adhesion and the initial relational expression for the paper. This makes it possible to have parameters for each type of paper, and as a result, the image forming apparatus 100 can be given an optimal initial value as a selection.

[0031] Figure 7 is a flowchart illustrating a detailed example of the automatic adjustment of the maximum density in the image forming system according to this embodiment. Specifically, Figure 7 is a flowchart illustrating a detailed example of the steps in step S3 shown in Figure 5-2.

[0032] First, the control unit 101 prints a chart for adjusting the maximum density (step S701). Next, the sensor value acquisition unit 101b acquires the current solid RGB value (hereinafter also referred to as solid RGB value) using a density sensor 220 such as an inline sensor (step S702). Next, the adjustment unit 101c calculates the difference ΔGap between the current solid RGB value and the target solid RGB value (hereinafter also referred to as the target solid RGB value), which is an example of a target color value (step S703).

[0033] Then, the adjustment unit 101c determines whether the difference ΔGap is less than a specified termination threshold (for example, ±0.05 for density) (step S704). If the difference ΔGap is greater than or equal to the specified termination threshold (step S704: No), the adjustment unit 101c performs a process to calculate the amount of adhesion based on the difference ΔGap (step S705), and reflects the calculated amount of adhesion in the image forming apparatus 100 (step S706).

[0034] Figure 8 is a flowchart showing an example of the flow of the process for calculating the amount of toner deposited in the image forming system according to this embodiment. First, the adjustment unit 101c calculates the difference ΔGap (step S801). If it is the first adjustment of the amount of toner deposited (step S802: Yes), the adjustment unit 101c determines the addition or subtraction of the amount of toner deposited based on the results of past adjustments of the amount of toner deposited or the existing amount of toner deposited stored in the non-volatile memory 1013c for each type of paper, and a function (f(x)) which is an example of a relationship (amount of toner deposited characteristic) between the toner concentration and the existing amount of toner deposited (step S805).

[0035] On the other hand, in the case of adjusting the amount of adhesion for the second time or later (step S802: No), the adjustment unit 101c obtains f(x) using the color measurement point (color value corresponding to the number of color measurements from the first to the current number) and determines the adjustment of the amount of adhesion (step S803). Next, the adjustment unit 101c considers the possibility that the amount of adhesion obtained by f(x) is inappropriate and determines the adjustment of the determined amount of adhesion according to at least one of the number of adjustments with respect to the target color value and the difference amount (difference ΔGap) (step S804).

[0036] Figure 9 illustrates an example of the toner adhesion adjustment process in the image forming system according to this embodiment. In Figure 9, the vertical axis represents the color values ​​of the image on the paper, and the horizontal axis represents the amount of toner adhered. Essentially, this is a problem of solving the equation: Target color value (e.g., toner density, RGB value) = f(x: amount of adhesion). This target color value differs each time the maximum density is adjusted for the first time, and f(x) may also differ depending on the paper, as well as the adjustment timing and the machine. Therefore, automatic adjustment to the maximum density that is applicable to any paper is difficult.

[0037] Furthermore, y: current density value (current toner density) relative to x: amount of toner deposited is not necessarily uniquely determined, and fluctuates with each adjustment due to the state of the image forming apparatus 100 and external disturbances. Expressed mathematically, this becomes a problem of solving the equation: Target color value (for example, target toner density) = f(x: amount of toner deposited) + noise. Well-known methods used in numerical analysis to solve such problems include Newton's method and the secant method, which is an advanced version of the bisection method. The former (Newton's method) converges quickly but is sensitive to initial values ​​and susceptible to disturbances. The latter (secant method) is robust but has the problem of slow convergence.

[0038] While there are several methods that improve upon these, in this embodiment, the adjustment unit 101c uses the method best suited to the following case: The number of prints required to estimate the relation f(x) is limited. This is because users dislike the consumption of toner and paper. Under conditions where the state of f(x) is unknown, the best method to solve the target color value (e.g., toner density) = f(x: amount of toner deposited) + noise within a few measurements (e.g., within 5), is a method that reaches close to the target color value in the initial adjustment as much as possible, like Newton's method, and is also robust to fluctuations, like the bisection method.

[0039] Next, an example of the toner adhesion adjustment process in the image forming system according to this embodiment will be described using Figure 10. Figure 10 is a diagram illustrating an example of the toner adhesion adjustment process in the image forming system according to this embodiment. In Figure 10, the vertical axis represents the color values ​​of the image on the paper, and the horizontal axis represents the amount of toner adhered.

[0040] (Example 1) The simplest case: Linear regression of measurement points (1) The first color measurement value (color value) is obtained by printing using the amount of adhesion currently set in the image forming apparatus 100. (2) Initial function: Use f0(x) to determine the amount of adhesion that produces the target maximum density (an example of a target color value). (3) When printing and measuring with the amount of adhesion determined in (2), the following colorimetric values ​​(color values) are obtained. (4) A linear regression of the measurement points is performed using the colorimetric values ​​obtained in (3). (5) Repeat steps (3) and (4) until the target maximum concentration is reached. This method uses a pre-defined f(x) for each type of paper during the first print run, and updates f(x) based on the obtained colorimetric values ​​during subsequent print runs. In other words, the first run uses f(x) obtained under as general a condition as possible to reach a value close to the target color, and from the second run onward, as the number of measurement points increases, f(x) is updated and optimized, allowing for more precise adjustment. In the second run, linear regression of the measurement points is performed based on the function values ​​at the endpoints of the interval. In the third run, it is also possible to use an approximation curve of three points. Possible methods for updating f(x) include multiplying f(x) by α to match the measurement points, or finding the approximation line with the smallest error using the least squares method.

[0041] (Example 2) The simplest case: In addition to case 1, it has the following characteristics. The adjustment unit 101c reduces or maintains the amount of adhesion based on the difference (difference ΔGap) between the target color value and the acquired color value (sensor value), or the number of updates. (1) The first color measurement value is obtained by printing using the adhesion amount currently set in the image forming apparatus 100. (2) Using the initial function f0(x), determine the amount of adhesive that produces the target maximum density (an example of a target color value). (3) Read the range corresponding to the difference (difference ΔGap) from the target color value, and if the amount of adhesion that produces the highest target density calculated is outside that range, perform a correction. (4) Correction is a correction that sets the value to the maximum (minimum) value on the side that exceeds the range, or multiplies the original amount of change, etc. (5) When the amount of adhesion is printed and measured, the following colorimetric values ​​are obtained. (6) Linear regression is performed from the obtained colorimetric values. (7) Repeat steps (3) to (4) until the target concentration is reached. Example 1 is useful when noise is small (for example, when the amount of adhesion changed based on the difference ΔGap (the amount of adhesion calculated by the process shown in Figure 7), as shown in Figure 10, is within the range of threshold 1), but when noise is large (for example, when the amount of adhesion calculated by the process shown in Figure 7, as shown in Figure 10, is outside the range of threshold 1), the linear regression is affected by noise and may produce measurement points that deviate significantly from the ideal amount of adhesion.

[0042] Here, the adjustment unit 101c may determine whether the amount of toner deposited has deviated significantly from the ideal amount by whether or not it exceeds a reasonable adjustment range. Basically, the toner density fluctuates by about 0.05 for every 0.02 units of deposited amount. However, this value is 0.05 ± A, depending on the paper, environment, and amount of toner deposited. This A is the range. Therefore, by setting A as large as possible, the adjustment unit 101c can determine that the amount of toner deposited has deviated significantly from the ideal amount if it exceeds this range.

[0043] (Example 3) In Example 3, unlike Example 1, the secant method or Newton's method is used to estimate the relation f(x) instead of linear regression. If dynamic estimation of the relation f(x) fails as in Example 2, a more daring estimation method than linear regression may be used if there is a means to statically adjust it. Alternatively, one may choose the better method between linear regression and the secant method.

[0044] Thus, according to the image forming apparatus 100 of this embodiment, by confirming the adjustment results regarding toner image transfer and updating the relational formula, the relationship between the current amount of toner deposited and the color value can be grasped each time the number of adjustments regarding toner image transfer is increased, and as a result the accuracy of the adjustment of the amount of toner deposited can be improved. Therefore, even if the optimal transfer voltage (amount of toner deposited) for obtaining the target color value is selected, cases where readjustment is necessary can be detected and the system can automatically proceed to readjustment.

[0045] The program executed by the image forming apparatus 100 in this embodiment is provided pre-installed in ROM 1013a or the like. The program executed by the image forming apparatus 100 in this embodiment may also be configured to be provided as an installable or executable file recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, or DVD (Digital Versatile Disk).

[0046] Furthermore, the program executed by the image forming apparatus 100 of this embodiment may be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. Alternatively, the program executed by the image forming apparatus 100 of this embodiment may be provided or distributed via a network such as the Internet.

[0047] The program executed in the image forming apparatus 100 of this embodiment has a modular configuration that includes the above-described parts (target value acquisition unit 101a, sensor value acquisition unit 101b, and adjustment unit 101c). In actual hardware, an example of a processor such as a CPU reads the program from the ROM 1013a and executes it, thereby loading the above-described parts onto the main memory, and generating the target value acquisition unit 101a, sensor value acquisition unit 101b, and adjustment unit 101c on the main memory.

[0048] In the above embodiment, the image forming apparatus of the present invention is described using an example in which it is applied to a multifunction device having at least two functions from among a copy function, a printer function, a scanner function, and a facsimile function. However, it can be applied to any image forming apparatus such as a copier, printer, scanner, or facsimile device.

[0049] Examples of the present invention are as follows: <1> A means for obtaining target color values, A sensor value acquisition means for acquiring the color values ​​of printed materials using an internal sensor, The system includes an adjustment means that changes the amount of toner deposited on the printed material based on the difference between the target color value and the color value obtained by the internal sensor. The aforementioned adjustment means is An image forming apparatus comprising: an update means for storing in advance a relational expression between the amount of adhesion and the color value, and updating the relational expression using the acquired color value. <2> The update means is, The sensor value acquisition means includes a correction means that corrects the relational expression each time it acquires the color value, The correction means modifies the relational expression so that the error between each color value and the relational expression is minimized. <1> The image forming apparatus described above. <3> The aforementioned adjustment means is Based on the difference between the target color value and the acquired color value, or the number of updates to the relational expression, the amount of adhesion is reduced or kept constant. <1> or <2> The image forming apparatus described above. <4> The aforementioned adjustment means is Based on at least one of the paper weight and texture, or using a color value measurement sensor or paper type identification sensor, the type of paper is identified, and the optimal initial adhesion amount and initial relational expression for the paper are selected. <1> from <3> An image forming apparatus as described in any one of the following. <5> The means for obtaining the target value is, It includes a color value storage means that stores multiple target color values ​​for the initial print as different profiles for each type of paper, The appropriate profile is applied according to the selected paper type to set the target color value. <1> from <4> An image forming apparatus as described in any one of the following. <6> An image forming method performed in an image forming apparatus, Steps to obtain the target color value, The steps include acquiring the color values ​​of the printed material using an internal sensor, The steps include changing the amount of toner applied to the printed material based on the difference between the target color value and the color value obtained by the internal sensor, The steps include updating the relationship between the amount of adhesion and the color value using the acquired color value, An image forming method including [specific details omitted]. <7> Computers, A means for obtaining target color values, A sensor value acquisition means for acquiring the color values ​​of printed materials using an internal sensor, Based on the difference between the target color value and the color value obtained by the internal sensor, it functions as an adjustment means to change the amount of toner deposited on the printed material. The aforementioned adjustment means is A program comprising: a program that pre-stores a relationship formula between the amount of adhesion and the color value, and an update means that updates the relationship formula using the acquired color value. [Explanation of Symbols]

[0050] 100 Image forming apparatus 101 Control Unit 101a Target value acquisition unit 101b Sensor value acquisition unit 101c Adjustment part 150 Printer Section 220 Concentration Sensor 221 Light-emitting element 222 Photodetector 1011 Image control CPU 1013 Storage section 1013a ROM 1013b RAM 1013c Non-volatile memory [Prior art documents] [Patent Documents]

[0051] [Patent Document 1] Japanese Patent Publication No. 2022-156245

Claims

1. A means for obtaining target color values, A sensor value acquisition means for acquiring the color values ​​of printed materials using an internal sensor, The system includes an adjustment means that changes the amount of toner deposited on the printed material based on the difference between the target color value and the color value obtained by the internal sensor. The aforementioned adjustment means is An image forming apparatus comprising: an update means for storing in advance a relational expression between the amount of adhesion and the color value, and updating the relational expression using the acquired color value.

2. The update means is, The sensor value acquisition means includes a correction means that corrects the relational expression each time it acquires the color value, The image forming apparatus according to claim 1, wherein the correction means modifies the relational expression so that the error between each color value and the relational expression is minimized.

3. The aforementioned adjustment means is The image forming apparatus according to claim 1 or 2, wherein the amount of adhesion is reduced or kept constant based on the difference between the target color value and the acquired color value, or the number of updates of the relational expression.

4. The aforementioned adjustment means is The image forming apparatus according to claim 1 or 2, which identifies the type of paper based on at least one of the paper weight and texture, or by using a color value measuring sensor or a paper type identification sensor, and selects the optimal initial adhesion amount and initial relational expression for the paper.

5. The means for obtaining the target value is, It includes a color value storage means that stores multiple target color values ​​for the initial print as different profiles for each type of paper, The image forming apparatus according to claim 1 or 2, wherein an appropriate profile is applied according to the type of paper selected to set the target color value.

6. An image forming method performed in an image forming apparatus, Steps to obtain the target color value, The steps include acquiring the color values ​​of the printed material using an internal sensor, The steps include changing the amount of toner applied to the printed material based on the difference between the target color value and the color value obtained by the internal sensor, The steps include updating the relationship between the amount of adhesion and the color value using the acquired color value, An image forming method including [specific details omitted].

7. Computers, A means for obtaining target color values, A sensor value acquisition means for acquiring the color values ​​of printed materials using an internal sensor, Based on the difference between the target color value and the color value obtained by the internal sensor, it functions as an adjustment means to change the amount of toner deposited on the printed material. The aforementioned adjustment means is A program comprising: a program that pre-stores a relationship formula between the amount of adhesion and the color value, and an update means that updates the relationship formula using the acquired color value.

Images