JP2020192785A - Image formation device and correction method - Google Patents

Abstract

To provide an image formation device that can determine a suitable discharge condition corresponding to a state and an environment of the image formation device.SOLUTION: An image formation device 100 comprises an image formation part 20, a first calculation part 11, a second calculation part 12 and a correction part 15. The image formation part 20 forms an image on a sheet Pa by discharging ink In. The first calculation part 11 calculates a predicted content percentage S of the ink In with respect to the sheet Pa on the basis of a diffusion coefficient D of the ink In. The second calculation part 12 calculates a predicted physical quantity Qcalc indicating a predicted color density of an image to be formed on the sheet Pa on the basis of the predicted content percentage S. A measurement part 30 measures an actual physical quantity Qexp indicating a color density of the image formed on the sheet Pa. The correction part 15 corrects the diffusion coefficient D on the basis of a ratio of the predicted physical quantity Qcalc to the actual physical quantity Qexp.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus and a correction method.

An image forming apparatus is known that ejects ink onto a sheet to form an image. The inkjet recording apparatus described in Patent Document 1 prints a bleeding check pattern at a preset color boundary. Next, the inkjet recording device captures a printed image and calculates the type and degree of defect. Then, the inkjet recording device feeds back the countermeasures to the optimum printing conditions for actual printing.

JP-A-2016-221880

However, the printing conditions depend on the state and environment of the inkjet recording device. Therefore, in the inkjet recording device described in Patent Document 1, the calculated optimum printing conditions (ejection conditions) may not be optimal depending on the state and environment of the inkjet recording device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus and a correction method capable of determining suitable ejection conditions according to the state and environment of the image forming apparatus.

According to the first aspect of the present invention, the image forming apparatus includes an image forming unit, a first calculation unit, a second calculation unit, and a correction unit. The image forming unit ejects ink to form an image on the sheet. The first calculation unit calculates the predicted content of ink with respect to the sheet based on the diffusion coefficient of ink. The second calculation unit calculates a predicted physical quantity indicating a predicted color density of an image formed on a sheet based on the predicted content rate. The measuring unit measures an actual physical quantity indicating the color density of the image formed on the sheet. The correction unit corrects the diffusion coefficient based on the ratio of the predicted physical quantity and the actual physical quantity.

According to the second aspect of the present invention, the correction method includes a procedure of ejecting ink to form an image on the sheet, a procedure of calculating the predicted content of ink with respect to the sheet based on the diffusion coefficient of ink, and a procedure of calculating the predicted content of ink with respect to the sheet. A procedure for calculating a predicted physical quantity indicating a predicted color density of an image formed on a sheet based on the predicted content, a procedure for measuring an actual physical quantity indicating a color density of the image formed on the sheet, and the above. It includes a procedure for correcting the diffusion coefficient based on the ratio of the predicted physical quantity to the actual physical quantity.

According to the present invention, suitable ejection conditions can be determined according to the state of the image forming apparatus and the environment.

It is a figure which shows the image forming apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the image forming apparatus which concerns on embodiment of this invention. (A) is a figure which shows ink at the time of starting penetration into a sheet. (B) is a figure which shows ink in the process of permeating into a sheet. (C) is a diagram showing a state in which the ink has completed permeation into the sheet. It is a flowchart which shows the image formation method which the image formation apparatus which concerns on embodiment of this invention executes. It is a flowchart which shows the correction method which the correction part which concerns on embodiment of this invention executes. It is a flowchart which shows the discharge condition determination method executed by the 1st determination part which concerns on embodiment of this invention. It is a figure which shows the image forming apparatus which concerns on the modification of this invention. It is a flowchart which shows the discharge condition determination method executed by the 1st determination part which concerns on the modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. In the figure, the same or corresponding parts are designated by the same reference numerals and the description is not repeated.

The image forming apparatus 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing an image forming apparatus 100. FIG. 2 is a schematic view showing the configuration of the image forming apparatus 100 according to the present embodiment. In the present embodiment, the image forming apparatus 100 is, for example, an inkjet recording apparatus. As shown in FIG. 1, the image forming apparatus 100 includes a control unit 10, an image forming unit 20, a measuring unit 30, a notification unit 40, and a storage unit 50. Further, as shown in FIG. 2, the image forming apparatus 100 includes a paper feeding unit 110, a sheet conveying unit 120, a discharging unit 130, and a maintenance unit 140.

The paper feeding unit 110 feeds the sheet Pa to the sheet conveying unit 120. The paper feed unit 110 of the present embodiment has a paper feed cassette 111 and a paper feed roller 112. The paper feed cassette 111 accommodates at least one sheet Pa. The paper feed roller 112 feeds the sheet Pa from the paper feed cassette 111 to the sheet transport unit 120. The sheet Pa is an example of a recording medium.

The sheet transport unit 120 transports the sheet Pa to the discharge unit 130. Specifically, the sheet transport unit 120 has a plurality of transport guides 121, a plurality of transport roller pairs 122, and a resist roller pair 123. The transport guide 121 constitutes a transport path for the sheet Pa. The transport roller pair 122 transports the sheet Pa along the transport path. The resist roller pair 123 adjusts the transfer timing of the sheet Pa to the regions facing the four head assemblies 21 to 24.

The sheet transport unit 120 of the present embodiment has a first transport unit 124 and a second transport unit 125. The first transport unit 124 faces the four head assemblies 21-24. The first transport unit 124 transports the sheet Pa in the region directly below the four head assemblies 21 to 24. The second transport unit 125 transports the sheet Pa sent out from the first transport unit 124 toward the discharge unit 130.

Based on the image data, the image forming unit 20 ejects ink In, which will be described later, with reference to FIGS. 3A to 3C, and forms an image on the sheet Pa. Specifically, the image forming unit 20 ejects the ink In based on the ink In ejection conditions determined based on the image data, and forms an image on the sheet Pa. The ink In ejection condition includes, for example, at least one of the amount of the ink In and the time for ejecting the ink In. The amount of ink In is, for example, the amount of ink In ejected by the image forming unit 20 per unit time. The amount of ink In ejected by the image forming unit 20 per unit time is, for example, the mass of the ink In ejected by the image forming unit 20 per unit time and the amount of ink In ejected by the image forming unit 20 per unit time. Includes at least one with volume.

The image forming unit 20 includes four head assemblies 21, 22, 23, and 24. The four head assemblies 21 to 24 include a first head assembly 21, a second head assembly 22, a third head assembly 23, and a fourth head assembly 24.

The recording heads provided in each of the four head assemblies 21 to 24 eject ink In toward the sheet Pa transported by the first transport unit 124. Specifically, each recording head of the four head assemblies 21 to 24 ejects ink In of different colors from each other. For example, the recording head of the first head assembly 21 ejects black ink In. The recording head of the second head assembly 22 ejects cyan-colored ink In. The recording head of the third head assembly 23 ejects magenta ink In. The recording head of the fourth head assembly 24 ejects yellow ink In.

The measuring unit 30 measures the actual physical quantity Qexp, which indicates the color density of the ink In discharged onto the sheet Pa. That is, the measuring unit 30 measures the actual physical quantity Qexp, which indicates the color density of the image formed on the sheet Pa. The measuring unit 30 includes four measuring units 31, 32, 33, and 34. The four measuring units 31 to 34 include a first measuring unit 31, a second measuring unit 32, a third measuring unit 33, and a fourth measuring unit 34. In the present embodiment, the larger the actual physical quantity Qexp, the larger the color density of the image.

The first measurement unit 31 is located downstream of the first head assembly 21 and upstream of the second head assembly 22 in the transport direction of the sheet Pa. The second measurement unit 32 is located downstream of the second head assembly 22 and upstream of the third head assembly 23 in the transport direction of the sheet Pa. The third measurement unit 33 is located downstream of the third head assembly 23 and upstream of the fourth head assembly 24 in the transport direction of the sheet Pa. The fourth measurement unit 34 is located downstream of the fourth head assembly 24 in the transport direction of the sheet Pa.

The four measuring units 31 to 34 include, for example, a reflective light sensor, a transmissive light sensor, or an ultrasonic sensor. When the four measuring units 31 to 34 are reflection type optical sensors, the four measuring units 31 to 34 have, for example, a light emitting unit and a light receiving unit. When the four measuring units 31 to 34 are reflection type optical sensors, the light emitting unit and the light receiving unit are arranged on the same side of the pair of surfaces of the sheet Pa. When the four measuring units 31 to 34 are transmissive optical sensors, the four measuring units 31 to 34 have, for example, a light emitting unit and a light receiving unit. When the four measuring units 31 to 34 are transmissive optical sensors, the light emitting unit and the light receiving unit are arranged on different surfaces of the pair of surfaces of the sheet Pa, respectively. That is, the light emitting unit and the light receiving unit are arranged so as to pass through the sheet Pa. Further, when the four measuring units 31 to 34 are ultrasonic sensors, the four measuring units 31 to 34 have, for example, a transmitting unit and a receiving unit. When the four measuring units 31 to 34 are ultrasonic sensors, the light emitting unit and the light receiving unit are arranged on the same side of the pair of sheets Pa.

The first measurement unit 31 measures the actual physical quantity Qexp, which indicates the color density of the ink In ejected by the recording head of the first head assembly 21 with respect to the sheet Pa. The second measurement unit 32 measures the actual physical quantity Qexp, which indicates the color density of the ink In ejected by the recording head of the second head assembly 22 with respect to the sheet Pa. The third measurement unit 33 measures the actual physical quantity Qexp, which indicates the color density of the ink In ejected by the recording head of the third head assembly 23 with respect to the sheet Pa. The fourth measurement unit 34 measures the actual physical quantity Qexp, which indicates the color density of the ink In ejected by the recording head of the fourth head assembly 24 with respect to the sheet Pa.

The discharge unit 130 discharges the sheet Pa to the outside of the apparatus main body. The discharge unit 130 of the present embodiment has a discharge tray 131 and a discharge roller pair 132. The discharge roller pair 132 sends the sheet Pa to the discharge tray 131.

The maintenance unit 140 maintains the recording heads of the four head assemblies 21 to 24. The maintenance unit 140 is located below the second transport unit 125 when recording an image on the sheet Pa, and moves to a position directly below the four head assemblies 21 to 24 during maintenance of the recording head. During maintenance of the recording head, the first transport unit 124 is moved to the retracted position. The retracted position is a position where the first transport unit 124 does not collide with the maintenance unit 140.

The maintenance unit 140 of the present embodiment has a cap portion 141 and a cleaning portion 142. The recording head has a nozzle surface. A plurality of nozzles for ejecting ink are arranged on the nozzle surface. The cap portion 141 has a capping member 141a. The capping member 141a caps the nozzle surface of the recording head to provide an environment in which the ink does not easily dry.

The cleaning unit 142 cleans the nozzle surface of the recording head. Specifically, the cleaning unit 142 has a wipe blade 142a. The wipe blade 142a contains, for example, a resin as a material. The wipe blade 142a is a cleaning member that cleans the nozzle surface.

The storage unit 50 includes semiconductor memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory), for example. Further, the storage unit 50 includes a storage device such as an HDD (Hard Disk Drive). The storage unit 50 stores a computer program executed by the control unit 10. Further, the storage unit 50 stores the first table 51, the plurality of second tables 52, and the third table 53. The first table 51, the second table 52, and the third table 53 will be described later.

The control unit 10 includes a processor. The processor includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 10 controls each element of the image forming apparatus 1. Specifically, the control unit 10 controls the image forming unit 20, the measuring unit 30, the notification unit 40, and the storage unit 50 by executing a computer program stored in the storage unit 50.

Further, the control unit 10 executes the computer program stored in the storage unit 50 to execute the first calculation unit 11, the second calculation unit 12, the third calculation unit 13, the correction unit 15, the first determination unit 16, and the like. It functions as a second decision unit 17 and a learning unit 18. That is, the control unit 10 includes a first calculation unit 11, a second calculation unit 12, a third calculation unit 13, a correction unit 15, a first determination unit 16, a second determination unit 17, and a learning unit 18. The first calculation unit 11, the second calculation unit 12, the third calculation unit 13, the correction unit 15, the first determination unit 16, the second determination unit 17, and the learning unit 18 will be described later.

The notification unit 40 is, for example, a display unit. The notification unit 40 is controlled by the control unit 10 to display a message. The message indicates, for example, the type of sheet Pa that meets the ejection conditions of ink In.

Next, the ink In that permeates the sheet Pa will be described with reference to FIGS. 3A to 3C. FIG. 3A is a diagram showing the ink In when the permeation into the sheet Pa is started. FIG. 3B is a diagram showing ink In in the process of penetrating into the sheet Pa. First, as shown in FIG. 3A, immediately after the ink In is ejected to the sheet Pa, the ink In stays on the front side surface of the sheet Pa. Then, as shown in FIG. 3B, the ink In permeates the inside of the sheet Pa toward the back side surface of the sheet Pa with the passage of time. Specifically, the ink In permeates the back side surface of the sheet Pa in the thickness direction L of the sheet Pa with the passage of time. FIG. 3C is a diagram showing a state in which the ink In has completed permeation into the sheet Pa.

The penetrance of the ink In into the sheet Pa changes based on at least one of the components of the ink In, the type of the sheet Pa, and the state and environment of the image forming apparatus 100. Therefore, the image forming apparatus 100 according to the present embodiment compares the predicted physical quantity Qcalc based on the predicted penetration n of the ink In into the sheet Pa with the actual physical quantity Qexp of the ink In into the sheet Pa. Then, the image forming apparatus 100 calculates the predicted physical quantity Qcalc more accurately based on the comparison result, and determines the ink In ejection condition based on the calculation result. As a result, the ink In ejection conditions can be determined according to the state and environment of the image forming apparatus 100. Hereinafter, a specific description will be given with reference to FIGS. 1 and 3.

First, the first calculation unit 11 calculates the predicted content rate S of ink In with respect to the sheet Pa based on the diffusion coefficient D of ink In. The predicted content rate S indicates the ratio of ink In contained in the sheet Pa. Specifically, the predicted content rate S indicates, for example, the ratio of the volume of ink In to the sum of the volume of sheet Pa and the volume of ink In.

In the present embodiment, the predicted content S of the ink In is calculated based on, for example, the elapsed time t, the coordinates x in the thickness direction L of the sheet Pa, and the diffusion coefficient D. The elapsed time t indicates, for example, the elapsed time from the time when the ink In is ejected to the sheet Pa. The coordinate x indicates the position of the sheet Pa in the thickness direction L. The predicted content S of ink In is calculated by, for example, a one-dimensional diffusion equation. However, the one-dimensional diffusion equation is an example of calculating the predicted content rate S of ink In, and the calculation of the predicted content rate S of ink In is not limited to the one-dimensional diffusion equation. The predicted content rate S of the ink In is calculated based on, for example, the predicted content rate calculation model represented by the following formula (1).

The diffusion coefficient D is calculated based on, for example, a diffusion coefficient D0, a temperature T, a reference temperature T0, a humidity W, a reference humidity W0, and a correction value P. The diffusion coefficient D0 indicates a reference diffusion coefficient determined for each type of ink In. The diffusion coefficient D0 includes, for example, information indicating the ejection conditions of the ink In. The first calculation unit 11 obtains the diffusion coefficient D0 with reference to, for example, the first table 51. The first table 51 stores the ejection conditions of the ink In and the diffusion coefficient D0 in association with each other. The first calculation unit 11 may calculate the diffusion coefficient D0 based on the ejection conditions of the ink In and the predetermined diffusion coefficient calculation model.

The temperature T indicates the temperature of the installation environment of the image forming apparatus 1. The reference temperature T0 indicates a reference temperature. Humidity W indicates the humidity of the installation environment of the image forming apparatus 1. Reference humidity W0 indicates the reference humidity. The correction value P is changed according to the type of sheet Pa. The user can arbitrarily set the diffusion coefficient D0, the reference temperature T0, the reference humidity W0, and the correction value P. The diffusion coefficient D is calculated based on, for example, the following equation (2).

Next, the first calculation unit 11 predicts the distribution of the predicted content rate S of ink In in the thickness direction L of the sheet Pa based on the diffusion coefficient D. Then, the first calculation unit 11 calculates the predicted penetration degree n of the ink In into the sheet Pa based on the distribution of the predicted content rate S of the ink In. Specifically, in the present embodiment, for example, in the first calculation unit 11, as shown in FIG. 3C, from the coordinates x where the predicted content rate S is equal to or less than a certain value to the front surface surface of the sheet Pa. The length is calculated as the predicted penetration n of the ink In into the sheet Pa. The predicted penetrance n of the ink In changes based on at least one of the components of the ink In, the type of the sheet Pa, and the state and environment of the image forming apparatus 100. Therefore, the predicted penetrance n of the ink In into the sheet Pa can be calculated more accurately according to the state and environment of the image forming apparatus 100.

Next, the second calculation unit 12 predicts the predicted color density of the image formed on the sheet Pa based on the predicted penetrability n of the ink In calculated based on the distribution of the predicted content rate S of the ink In. Calculate the physical quantity Qcalc. The predicted physical quantity Qcalc correlates with the predicted color density of the image formed on the sheet Pa. The predicted physical quantity Qcalc indicates, for example, the reflectance of light or sound indicating the predicted color density of the image formed on the sheet Pa, or the transmittance of light or sound. In the present embodiment, for example, the larger the predicted physical quantity Qcalc, the larger the predicted color density. Therefore, the predicted physical quantity Qcalc can be calculated according to the type of the measuring unit 30.

In the present embodiment, the predicted physical quantity Qcalc is calculated based on, for example, the printing rate u, the attenuation coefficient τ, the physical quantity Ru0, the physical quantity Ru1, and the predicted penetrance n. The print ratio u indicates, for example, the ratio of the area where the image is formed to the area of the sheet Pa, or the ratio of the area of the area where the image is formed to the area of the area where the image can be formed in the sheet Pa. .. That is, the print rate u changes according to the image formed on the sheet Pa. When the print rate u is 0, the sheet Pa is blank. When the print rate u is 1, an image is formed on the entire surface of the sheet Pa. The attenuation coefficient τ indicates a coefficient related to the attenuation of the predicted physical quantity Qcalc. The physical quantity Ru0 indicates the physical quantity of the sheet Pa when the printing rate u is 0. The physical quantity Ru0 changes, for example, based on the type of sheet Pa. The physical quantity Ru1 indicates the physical quantity of the image formed on the sheet Pa when the printing rate u is 1. The physical quantity Ru1 changes based on, for example, at least one of the type of sheet Pa and the component of ink In. The predicted physical quantity Qcalc is calculated based on, for example, the physical quantity prediction model represented by the following equation (3).

The correction unit 15 determines whether or not the evaluation time of the diffusion coefficient D has arrived. The evaluation time of the diffusion coefficient D is, for example, when a predetermined period elapses from the time when the image forming unit 20 forms an image on the sheet Pa, or when the image forming unit 20 forms an image on a predetermined number of sheets Pa, the image is formed. When the time when the device 100 is not operating reaches the first predetermined time, and when the total time for the image forming unit 20 to eject the ink In to the sheet Pa reaches the second predetermined time, the image forming device 100 is installed. When the difference between the environment temperature T and the reference temperature T0 of the image forming apparatus 100 is equal to or greater than the first predetermined value, or the difference between the humidity W of the installation environment of the image forming apparatus 100 and the reference humidity W0 of the image forming apparatus 100. Is equal to or greater than the second predetermined value. The predetermined period is, for example, 6 months. The user can arbitrarily set the predetermined period, the predetermined number of sheets, the first predetermined time, the second predetermined time, the first predetermined value, and the second predetermined value. Therefore, it is possible to prevent the diffusion coefficient D from being unnecessarily evaluated. As a result, the time for executing the process for evaluating the diffusion coefficient D can be reduced, and the convenience of the user is improved.

The correction unit 15 evaluates the diffusion coefficient D in response to the determination by the correction unit 15 that the evaluation time of the diffusion coefficient D has arrived. The correction unit 15 corrects the diffusion coefficient D based on the evaluation result of the diffusion coefficient D. Specifically, in response to the correction unit 15 determining that the evaluation time of the diffusion coefficient D has arrived, the correction unit 15 acquires the difference between the predicted physical quantity Qcalc and the actual physical quantity Qexp. Then, the correction unit 15 determines whether or not the difference between the predicted physical quantity Qcalc and the actual physical quantity Qexp is equal to or greater than the threshold value. When the correction unit 15 determines that the difference between the predicted physical quantity Qcalc and the actual physical quantity Qexp is less than the threshold value, the correction unit 15 does not correct the diffusion coefficient D. Therefore, the time for executing the process for correcting the diffusion coefficient D can be reduced, and the convenience of the user is improved.

On the other hand, when the correction unit 15 determines that the difference between the predicted physical quantity Qcalc and the actual physical quantity Qexp is equal to or greater than the threshold value, the correction unit 15 uses the predicted physical quantity Qcalc calculated by the second calculation unit 12 and the actual measured by the measurement unit 30. The diffusion coefficient D is corrected based on the ratio with the physical quantity Qexp. Therefore, the diffusion coefficient D can be corrected according to the state and environment of the image forming apparatus 100. As a result, the predicted content rate S according to the state and environment of the image forming apparatus 100 can be calculated. If the predicted content rate S according to the state and environment of the image forming apparatus 100 can be calculated, suitable ink In ejection conditions can be determined.

The correction unit 15 corrects the diffusion coefficient D based on, for example, the following equation (4). The correction unit 15 may correct the diffusion coefficient D based on the predicted physical quantity Qcalc with respect to the actual physical quantity Qexp, or may correct the diffusion coefficient D based on the actual physical quantity Qexp with respect to the predicted physical quantity Qcalc. The diffusion coefficient Dnew indicates the corrected diffusion coefficient. The diffusion coefficient D indicates the diffusion coefficient before correction.

Next, the ejection conditions of the ink In will be described. The third calculation unit 13 calculates the target penetration ntv of the ink In into the sheet Pa based on the target physical quantity Qtv indicating the target color density of the image formed on the sheet Pa. The target color density is determined based on the image data and the type of sheet Pa. The third calculation unit 13 substitutes the target physical quantity Qtv into the Qcalc of the above physical quantity prediction model to calculate the target penetrance ntv. The target color density and the target physical quantity Qtv correlate with each other.

Then, the first determination unit 16 determines the ejection conditions of the ink In ejected by the image forming unit 20 based on the corrected diffusion coefficient Dnew and the target penetrance ntv calculated by the third calculation unit 13. In the present embodiment, specifically, the plurality of second tables 52 stored in the storage unit 50 correspond to a plurality of values of diffusion coefficients D, respectively. The first determination unit 16 corresponds to the target penetration ntv calculated by the third calculation unit 13, for example, with reference to the second table 52 corresponding to the corrected diffusion coefficient Dnew among the plurality of second tables 52. The ejection conditions of the ink In to be discharged are determined. The second table 52 stores the target penetrance ntv and the ejection conditions of the ink In in association with each other. Therefore, the ink ejection conditions can be determined according to the state of the image forming apparatus 100 and the environment. As a result, a higher quality image can be formed on the sheet Pa according to the state and environment of the image forming apparatus 100.

The image forming unit 20 forms an image on the sheet Pa by ejecting the ink In to the sheet Pa based on the determined ejection conditions of the ink In. Therefore, the predicted content rate S of ink In with respect to the sheet Pa can be calculated more accurately based on the diffusion coefficient Dnew corrected according to the state and environment of the image forming apparatus 100. As a result, the ejection conditions of the ink In ejected by the image forming unit 20 can be determined based on the predicted penetrance n based on the distribution of the predicted content rate S calculated according to the state and environment of the image forming apparatus 100. In other words, the ejection conditions can be determined according to the state and environment of the image forming apparatus 100. As a result, a high-quality image can be formed by the sheet Pa according to the state and environment of the image forming apparatus 100.

The second determination unit 17 determines the type of sheet Pa on which the image is formed by the image forming unit 20 based on the ink ejection conditions determined by the first determination unit 16. Specifically, the second determination unit 17 determines whether or not the type of sheet Pa housed in the paper feed cassette 111 conforms to the ink In ejection conditions determined by the first determination unit 16. When the second determination unit 17 determines that the type of sheet Pa housed in the paper feed cassette 111 conforms to the ink In ejection conditions determined by the first determination unit 16, the ink In is ejected based on the ejection conditions. The image forming unit 20 is controlled so as to form an image on the sheet Pa.

On the other hand, when the second determination unit 17 determines that the type of sheet Pa housed in the paper feed cassette 111 does not meet the ink In ejection conditions determined by the first determination unit 16, refer to the third table 53. Then, the type of the sheet Pa that matches the ejection conditions of the ink In determined by the first determination unit 16 is determined. The third table 53 stores the type of sheet Pa and the ejection condition of ink In in association with each other. Then, the second determination unit 17 controls the notification unit 40 so as to notify the type of the determined sheet Pa. Therefore, it is possible to determine the ink In ejection conditions and the type of sheet Pa according to the state and environment of the image forming apparatus 100. As a result, a higher quality image can be formed on the sheet Pa according to the state and environment of the image forming apparatus 100.

Next, the learning unit 18 will be described. The learning unit 18 shows information indicating the characteristics of the ink In, information indicating the temperature of the installation environment of the image forming apparatus 100, information indicating the humidity of the installation environment of the image forming apparatus 100, and the state of the image forming apparatus 20. At least one of the information is associated with the diffusion coefficient D for learning. Specifically, the learning unit 18 includes information indicating the characteristics of the ink In, information indicating the temperature of the environment of the image forming apparatus 100, information indicating the humidity of the environment of the image forming apparatus 100, and the image forming unit 20. Machine learning is performed by associating at least one of the information indicating the state with the diffusion coefficient D.

The information indicating the characteristics of the ink In includes, for example, information indicating the physical properties of the ink In. Specifically, the information indicating the characteristics of the ink In includes, for example, information indicating the viscosity of the ink In and / or information indicating the surface tension of the ink In. The information indicating the viscosity of the ink In and the information indicating the surface tension of the ink In are calculated based on the temperature and humidity of the environment of the image forming apparatus 100. Further, the information indicating the state of the image forming unit 20 includes, for example, at least one of information indicating a clogged state of the recording head and a state indicating deterioration of the recording head. Specifically, the information indicating the state of the image forming unit 20 is calculated based on, for example, an evaluation function including information indicating clogging and / or dirt of the recording head.

Learning includes machine learning. Machine learning includes, for example, supervised learning, unsupervised learning, and reinforcement learning. Machine learning is configured, for example, by a neural network (Neural Network) or a support vector machine (Support Vector Machine). The neural network has an input layer, a hidden layer (intermediate layer), and an output layer. The neural network uses an error backpropagation method to reduce the error between the output value and the optimum solution in the output layer.

Further, the machine learning may be deep learning. Deep learning is composed of a neural network having an input layer, two or more hidden layers, and an output layer. Specifically, deep learning is composed of, for example, a convolutional neural network (Convolutional Neural Network), a recurrent neural network (Recurrent Neural Network), and a Boltzmann machine.

The learning unit 18 outputs a diffusion coefficient D suitable for the state and environment of the image forming apparatus 100 based on the learning result. Preferably, the learning unit 18 outputs the optimum diffusion coefficient D based on the learning result. Therefore, the first determination unit 16 can determine the ejection conditions of the ink In based on the diffusion coefficient D suitable for the state of the image forming apparatus 100 and the environment.

Next, with reference to FIG. 4, an image forming method executed by the image forming unit 20 of the image forming apparatus 100 according to the embodiment will be described. FIG. 4 is a flowchart showing an image forming method executed by the image forming apparatus 1 according to the embodiment.

In step S11, the first determination unit 16 determines the ink In ejection conditions based on the image data and the diffusion coefficient D.

In step S13, the control unit 10 controls the image forming unit 20 so as to eject the ink In and form an image on the sheet Pa based on the ink In ejection conditions determined in step S11. That is, the image forming unit 20 ejects the ink In based on the ejection conditions of the ink In, and forms an image on the sheet Pa.

In step S15, the control unit 10 controls the measurement unit 30 so as to measure the actual physical quantity Qexp indicating the color density of the image formed on the sheet Pa. That is, the measuring unit 30 measures the actual physical quantity Qexp, which indicates the color density of the image formed on the sheet Pa.

Next, with reference to FIG. 5, a method for correcting the diffusion coefficient D executed by the correction unit 15 according to the embodiment will be described. FIG. 5 is a flowchart showing a correction method of the diffusion coefficient D executed by the correction unit 15 according to the embodiment.

In step S21, the learning unit 18 includes information indicating the characteristics of the ink In, information indicating the temperature of the installation environment of the image forming apparatus 100, information indicating the humidity of the installation environment of the image forming apparatus 100, and the image forming unit 20. Machine learning is performed in association with at least one of the information indicating the state of and the diffusion coefficient D. Then, the learning unit 18 outputs a diffusion coefficient D suitable for the state and environment of the image forming apparatus 100 based on the learning result.

In step S23, the correction unit 15 determines whether or not the evaluation time of the diffusion coefficient D has arrived. If a negative determination (No) is made in step S23, the process proceeds to step S21 again. If a positive determination (Yes) is made in step S23, the process proceeds to step S25.

In step S25, the first calculation unit 11 acquires the ink In ejection conditions determined in step S11 of FIG. In step S27, the first calculation unit 11 calculates the predicted content rate S based on the diffusion coefficient D of the ink In output in step S21 and the ejection conditions acquired in step S25. In step S29, the first calculation unit 11 calculates the predicted penetration n of ink In into the sheet Pa based on the distribution of the predicted content rate S calculated in step S27.

In step S31, the second calculation unit 12 calculates the predicted physical quantity Qcalc based on the predicted penetrance n calculated in step S29.

In step S33, the correction unit 15 calculates the difference between the predicted physical quantity Qcalc calculated in step S31 and the actual physical quantity Qexp measured in step S15 of FIG.

In step S35, the correction unit 15 determines whether or not the difference between the predicted physical quantity Qcalc calculated in step S33 and the actual physical quantity Qexp is equal to or greater than the threshold value. If a negative determination is made in step S35, the process proceeds to step S21 again. If a positive determination (Yes) is made in step S35, the process proceeds to step S37.

In step S37, the correction unit 15 corrects the diffusion coefficient D based on the ratio of the predicted physical quantity Qcalc and the actual physical quantity Qexp. Then, the correction unit 15 acquires the corrected diffusion coefficient Dnew.

Next, the discharge condition determination method executed by the first determination unit 16 according to the embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing a discharge condition determination method executed by the first determination unit 16 according to the embodiment.

In step S41, the third calculation unit 13 calculates the target penetrance ntv based on the target physical quantity Qtv.

In step S43, the first determination unit 16 ejects the target penetration ntv calculated in step S41 and the corrected diffusion coefficient Dnew acquired in step S37 of FIG. 5 by the image forming unit 20. Determine the ink ejection conditions.

In step S45, the second determination unit 17 determines whether or not the type of sheet Pa housed in the paper feed cassette 111 conforms to the ink In ejection conditions determined in step S43. If a positive determination (Yes) is made in step S45, the process proceeds to step S51.

In step S51, the control unit 10 controls the image forming unit 20 so as to form an image on the sheet Pa housed in the paper feed cassette 111. That is, the image forming unit 20 ejects the ink In based on the ink In ejection conditions determined in step S43, and forms an image on the sheet Pa accommodated in the paper feed cassette 111.

On the other hand, if a negative determination (No) is made in step S45, the process proceeds to step S47. In step S47, the second determination unit 17 determines the type of the sheet Pa with reference to the third table 53, based on the ink In ejection conditions determined in step S43.

In step S49, the control unit 10 controls the notification unit 40 so as to notify the type of sheet Pa determined in step S47. That is, the notification unit 40 notifies the type of the sheet Pa determined in step S47.

(Modification example)
Next, a modified example of the embodiment will be described with reference to FIGS. 7 and 8. The modified example differs from the embodiment in that the target content rate Stv is calculated based on the target penetrance ntv and the ink In ejection conditions are determined based on the target content rate Stv. Hereinafter, with respect to the modified example, matters different from the embodiment will be described, and the description of the portion overlapping with the embodiment will be omitted.

FIG. 7 shows an image forming apparatus 100a according to a modified example. The image forming apparatus 100a includes a control unit 10a. The control unit 10a further includes a fourth calculation unit 14. The fourth calculation unit 14 calculates the target content rate Stv of ink In with respect to the sheet Pa based on the corrected diffusion coefficient Dnew and the target penetrance ntv. Then, the first determination unit 16 determines the ejection conditions of the ink In ejected by the image forming unit 20 based on the corrected diffusion coefficient Dnew and the target content Stv. Therefore, the ink In ejection conditions can be determined according to the state of the image forming apparatus 100a and the environment. As a result, a higher quality image can be formed on the sheet Pa according to the state and environment of the image forming apparatus 100a.

Next, with reference to FIG. 8, the correction method executed by the first determination unit 16 according to the modified example will be described. FIG. 8 is a flowchart showing a correction method executed by the first determination unit 16 according to the modified example. Step S61 of FIG. 8 has the same processing content as step S41 of FIG. 6, and steps S67 to S73 of FIG. 8 have the same processing content as steps S45 to S51 of FIG. To do.

In step S63, the fourth calculation unit 14 calculates the target content rate Stv based on the target penetrance ntv and the corrected diffusion coefficient Dnew.

In step S65, the first determination unit 16 determines the ink In ejection conditions based on the target content Stv calculated in step S63 and the corrected diffusion coefficient Dnew.

The embodiments of the present invention have been described above with reference to the drawings (FIGS. 1 to 8). However, the present invention is not limited to the above-described embodiment, and can be implemented in various embodiments without departing from the gist thereof (for example, (1) to (7) shown below). The drawings are schematically shown mainly for each component for easy understanding, and the thickness, length, number, etc. of each component shown are different from the actual ones for the convenience of drawing creation. .. Further, the shape, dimensions, etc. of each component shown in the above embodiment are merely examples, and are not particularly limited, and various changes can be made without substantially deviating from the effects of the present invention.

(1) As described with reference to FIG. 2, the measuring unit 30 includes four measuring units 31 to 34. However, as long as the measuring unit 30 measures the actual physical quantity Qexp indicating the color density of the image formed on the sheet Pa, the measuring unit 30 may include one measuring unit 30. One measuring unit 30 is located, for example, downstream of the fourth head assembly 24. One measuring unit 30 measures, for example, an actual physical quantity Qexp indicating the color density of the ink In ejected by the four head assemblies 21 to 24. Then, the correction unit 15 corrects the diffusion coefficient D based on the ratio of, for example, the actual physical quantity Qexp of the four-color ink In and the predicted physical quantity Qcalc of the four-color ink In.

Further, the measuring unit 30 may include two or three measuring units 30. The two or three measuring units 30 measure the actual physical quantity Qexp, which indicates the color density of the ink In ejected by one or more head assemblies 21 to 24, respectively. For example, the two measuring units 30 may measure the actual physical quantity Qexp, which indicates the color density of the two colors of ink In, respectively. In this case, the correction unit 15 may correct the diffusion coefficient D for each of the two color inks In.

(2) The order of steps S21 to S37 in FIG. 5, the order of steps S41 to S51 in FIG. 6, and the order of steps S61 to S71 in FIG. 8 can be changed as appropriate.

(3) As described with reference to FIG. 3, the first calculation unit 11 transfers the length from the coordinate x at which the predicted content rate S is equal to or less than a certain value to the front side surface of the sheet Pa to the sheet Pa. It was calculated as the predicted penetrance n of ink In. However, when the predicted content rate S in the reference coordinate x0 in the thickness direction L of the sheet Pa is equal to or greater than the threshold value, the first calculation unit 11 sets the length from the reference coordinate x0 to the front side surface of the sheet Pa to the sheet Pa. It may be calculated as the predicted penetrance n of the ink In. The reference coordinate x0 and the threshold value can be arbitrarily set by the user.

(4) As described with reference to FIG. 1, the storage unit 50 stores a plurality of second tables 52. However, the storage unit 50 may store one second table 52.

(5) As described with reference to FIG. 3, the second determination unit 17 determines the type of sheet Pa that matches the ejection conditions of ink In. Then, the control unit 10 controlled the notification unit 40 so as to notify the type of the sheet Pa determined by the second determination unit 17. However, as long as the second determination unit 17 determines the type of sheet Pa that matches the ink In ejection conditions, the second determination unit 17 is a type of the plurality of paper cassettes 111 that matches the ink In ejection conditions. The paper feed cassette 111 in which the sheet Pa is housed may be determined. Then, the control unit 10 controls the paper feed roller 112 corresponding to the paper feed cassette 111 determined by the second determination unit 17, and the sheet Pa housed in the paper feed cassette 111 determined by the second determination unit 17. May be sent to the sheet transport unit 120.

(6) As described with reference to FIG. 3, in the present embodiment, the first determination unit 16 refers to the second table 52 corresponding to the corrected diffusion coefficient Dnew among the plurality of second tables 52. Therefore, the ejection conditions of the ink In corresponding to the target penetrance ntv calculated by the third calculation unit 13 were determined. However, as long as the first determination unit 16 determines the ink In ejection conditions, the first determination unit 16 may determine the ink In ejection conditions based on the learning result of the learning unit 18. In this case, the learning unit 18 learns by associating the target penetrance ntv with the ejection conditions of the ink In. Then, based on the learning result of the learning unit 18, the first determination unit 16 determines the ink In ejection condition. Further, the learning unit 18 may determine the type of sheet Pa on which the image is formed by the image forming unit 20 based on the determined ink In ejection conditions.

In addition, as long as the first determination unit 16 determines the ink In ejection conditions, the first determination unit 16 changes the ink In ejection conditions, and the variable ink In ejection conditions, the predicted content rate calculation model, and the ink In ejection conditions. The optimum ink In ejection conditions may be determined based on the physical quantity prediction model.

(7) As described with reference to FIGS. 1 and 2, in the present embodiment, the measuring unit 30 measures the actual physical quantity Qexp indicating the color density of the image formed on the sheet Pa. The measuring unit 30 may measure the actual physical quantity Qexp each time an image is formed on the sheet Pa, or may measure the actual physical quantity Qexp at an arbitrary timing. The control unit 10 may monitor the state and environment of the image forming apparatus 100 based on, for example, the actual physical quantity Qexp measured by the measurement unit 30.

The present invention is available in the field of image forming apparatus and correction method, and has industrial applicability.

1 Image forming device 10 Control unit 11 1st calculation unit 12 2nd calculation unit 13 3rd calculation unit 14 4th calculation unit 15 Correction unit 16 1st determination unit 17 2nd determination unit 18 Learning unit 20 Image formation unit 30 Measurement unit 40 Notification unit D Diffusion coefficient In ink Pa sheet Qcal Predicted physical quantity Qexp Actual physical quantity Qtv Target physical quantity S Predicted content rate

Claims (9)

An image forming part that ejects ink to form an image on a sheet,
A first calculation unit that calculates the predicted content of the ink with respect to the sheet based on the diffusion coefficient of the ink.
A second calculation unit that calculates a predicted physical quantity indicating a predicted color density of an image formed on the sheet based on the predicted content rate.
A measuring unit that measures an actual physical quantity that indicates the color density of the image formed on the sheet,
An image forming apparatus including a correction unit that corrects the diffusion coefficient based on the ratio of the predicted physical quantity and the actual physical quantity. A third calculation unit that calculates the target penetration of the ink into the sheet based on a target physical quantity indicating the target color density of the image formed on the sheet.
The image forming apparatus according to claim 1, further comprising a first determining unit for determining the ejection conditions of the ink ejected by the image forming unit based on the corrected diffusion coefficient and the target penetrance. A third calculation unit that calculates the target penetration of ink into the sheet based on a target physical quantity that indicates the target color density of the image formed on the sheet.
A fourth calculation unit that calculates the target content of the ink with respect to the sheet based on the corrected diffusion coefficient and the target penetrance.
The image forming apparatus according to claim 1, further comprising a first determining unit for determining the ejection conditions of the ink ejected by the image forming unit based on the corrected diffusion coefficient and the target content rate. The image forming according to claim 2 or 3, further comprising a second determining unit that determines the type of sheet on which the image is formed by the image forming unit based on the ejection conditions determined by the first determining unit. apparatus. The correction unit
It is determined whether or not the difference between the predicted physical quantity and the actual physical quantity is equal to or greater than the threshold value.
The diffusion coefficient is corrected based on the ratio of the predicted physical quantity and the actual physical quantity when it is determined that the difference between the predicted physical quantity and the actual physical quantity is equal to or larger than the threshold value. The image forming apparatus according to any one item. The correction unit
It is determined whether or not the evaluation time of the diffusion coefficient has arrived, and
In response to the determination that the evaluation time has arrived, it is determined whether or not the difference between the predicted physical quantity and the actual physical quantity is equal to or greater than the threshold value.
The evaluation period is such that when a predetermined period elapses from the time when the image forming unit forms an image on the sheet, or when the image forming unit forms an image on a predetermined number of sheets, the image forming apparatus is operating. When the absence time reaches the first predetermined time, and when the total time for the image forming unit to eject the ink to the sheet reaches the second predetermined time, the temperature of the installation environment of the image forming apparatus and the image forming. When the difference from the reference temperature of the device is equal to or greater than the first predetermined value, or when the difference between the humidity of the installation environment of the image forming apparatus and the reference humidity of the image forming apparatus is equal to or greater than the second predetermined value. , The image forming apparatus according to claim 5. At least one of information indicating the characteristics of the ink, information indicating the temperature of the installation environment of the image forming apparatus, information indicating the humidity of the installation environment of the image forming apparatus, and information indicating the state of the image forming portion. The image forming apparatus according to any one of claims 1 to 6, further comprising a learning unit that learns in association with the diffusion coefficient. The image forming apparatus according to any one of claims 1 to 7, wherein the predicted physical quantity indicates the reflectance of light or sound indicating the predicted color density, or the transmittance of light or sound. The procedure for ejecting ink to form an image on a sheet,
A procedure for calculating the predicted content of the ink with respect to the sheet based on the diffusion coefficient of the ink, and
A procedure for calculating a predicted physical quantity indicating a predicted color density of an image formed on the sheet based on the predicted content rate, and a procedure for calculating the predicted physical quantity.
A procedure for measuring an actual physical quantity indicating the color density of the image formed on the sheet, and
A correction method including a procedure for correcting the diffusion coefficient based on the ratio of the predicted physical quantity to the actual physical quantity.

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