Image forming apparatus

Abstract

To provide a technique that can reduce a time for calibration during initial installation.SOLUTION: An image forming apparatus comprises: receiving means that receives user input as to whether to execute first calibration or second calibration as calibration; and control means that, when executing the first calibration, forms a first test pattern on a recording material in a first image forming mode, generates first correction information associated with the first image forming mode, and generates second correction information associated with a second image forming mode based on the first correction information, and when executing the second calibration, forms the first test pattern on the recording material in an image forming mode designated by a user, and generates correction information associated with the designated image forming mode. When not executing the first calibration, the control means configures the receiving means to receive only the user input to execute the first calibration.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present disclosure relates to calibration technology in an image forming apparatus.

Background Art

[0002] The density (tone) of an image formed by an image forming apparatus may change due to environmental changes, changes over time, etc. In order to bring the density of the formed image closer to the target density, the image forming apparatus performs density calibration (hereinafter simply referred to as calibration). Patent Document 1 discloses a configuration for generating correction information for correcting image forming conditions related to density by reading a tone pattern formed on a recording material. Patent Document 2 discloses a configuration for forming color patches at regular intervals while performing image formation based on a job and determining correction information based on the detection results of the color patches.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Calibration must be performed for each type of image formation. Specifically, the image forming apparatus performs image formation at a process speed corresponding to the type of recording material. Here, correction information obtained from calibration performed at the first process speed can be used for image formation at the first process speed, but may not be usable for image formation at a second process speed different from the first process speed. Similarly, correction information obtained from calibration using the first type of halftone processing can be used for image formation using the first type of halftone processing, but may not be usable for image formation using a second type of halftone processing different from the first type. Furthermore, correction information obtained from calibration performed at the first resolution can be used for image formation at the first resolution, but may not be usable for image formation at a second resolution different from the first resolution.

[0005] Thus, image formation types are distinguished by factors such as the image formation process speed, resolution, and halftone processing, and are also referred to as "image formation modes" below. When an image forming apparatus has multiple image formation modes, it requires correction information for each image formation mode. For example, during the initial setup of an image forming apparatus, it is common to generate correction information for each of the multiple image formation modes. For this reason, performing calibration for each of the multiple image formation modes increases the time required for calibration.

[0006] This disclosure provides a technology that can shorten the calibration time during initial installation. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, an image forming apparatus includes: a conversion means for converting image data based on conversion conditions; an image forming means for forming an image on a recording material based on the image data converted by the conversion means; a first detection means for detecting the image formed on the recording material by the image forming means; and a control means that performs a first calibration for generating a first conversion condition used for forming an image at a first image forming speed based on the detection result of the first detection means of a first test pattern formed by the image forming means at a first image forming speed, and a second conversion condition used for forming an image at a second image forming speed different from the first image forming speed; and a second calibration for generating a second conversion condition used for forming an image at a second image forming speed based on the detection result of the first detection means of a second test pattern formed by the image forming means at a second image forming speed. A receiving means for receiving user instruction information that instructs the execution of calibration, Equipped with, If the first calibration has not been performed, the receiving means does not accept the user instruction information instructing the execution of the second calibration. The control means is characterized in that it does not perform the second calibration during initial installation. [Effects of the Invention]

[0008] According to this disclosure, the calibration time during initial setup can be shortened. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic cross-sectional view of an image forming apparatus according to one embodiment. [Figure 2] A diagram showing an example of the relationship between concentration sensor output and concentration. [Figure 3] A flowchart of a first type of calibration according to one embodiment. [Figure 4] A diagram illustrating an example of the relationship between detected concentration, first target concentration, and grayscale correction table. [Figure 5] An explanatory diagram of a method for determining the second target concentration according to one embodiment. [Figure 6] This diagram shows an example of the screen displayed when performing the second calibration. [Figure 7] This diagram shows an example of the screen displayed when performing the second calibration. [Figure 8] This figure shows an example of the screen displayed when performing the first calibration. [Figure 9] A flowchart of the first calibration according to one embodiment. [Figure 10] A flowchart of the first calibration according to one embodiment. [Figure 11] A figure showing coefficient information used to determine the second target concentration according to one embodiment. [Modes for carrying out the invention]

[0010] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0011] In the following, each embodiment will be described based on an electrophotographic image forming apparatus. However, the contents of this disclosure are also applicable to other types of image forming apparatuses, such as inkjet and dye-sublimation types.

[0012] <First Embodiment> Figure 1 is a schematic cross-sectional view of the image forming apparatus 100. The image forming apparatus 100 includes a printer unit B and an image reading unit A. The image reading unit A reads the image of the original document and outputs image data representing the image of the original document to the printer control unit 109 of the printer unit B. The printer unit B forms an image on the recording material P based on the image data from the image reading unit A or image data received from an external device via a network (not shown). The configuration of the printer unit B will be described below.

[0013] The image forming units PY, PM, PC, and PK respectively form yellow, magenta, cyan, and black toner images and transfer them to the intermediate transfer belt 6. Although the colors of the toners used by the image forming units PY, PM, PC, and PK for image formation are different, their configurations are the same. In FIG. 1, at the end of the reference signs indicating the members constituting the image forming units PY, PM, PC, and PK, the letters "Y", "M", "C", and "K" are respectively assigned. However, when there is no need to distinguish colors in the following description, reference signs with the letters "Y", "M", "C", and "K" at the end omitted are used.

[0014] The photoreceptor 1 is an image carrier and is rotationally driven in the counterclockwise direction in the figure during image formation. The charging device 2 charges the surface of the photoreceptor 1 to a uniform potential. The exposure device 3 exposes the photoreceptor 1 based on the image signal from the printer control unit 109 and forms an electrostatic latent image on the photoreceptor 1. The developing device 4 outputs a developing voltage to attach toner to the electrostatic latent image of the photoreceptor 1 and forms a toner image on the photoreceptor 1. The primary transfer roller 7 outputs a primary transfer voltage to transfer the toner image of the photoreceptor 1 to the intermediate transfer belt 6. By overlapping the toner images of each photoreceptor 1 and transferring them to the intermediate transfer belt 6, various colors can be reproduced.

[0015] The intermediate transfer belt 6 is an image carrier and is rotationally driven in the clockwise direction in the figure during image formation. Thereby, the toner image on the intermediate transfer belt 6 is conveyed to the opposing position of the secondary transfer roller 64. On the other hand, the recording material (sheet) P stored in the cassette 65 is conveyed to the opposing position of the secondary transfer roller 64 by the rollers 66 and 67. The secondary transfer roller 64 outputs a secondary transfer voltage to transfer the toner image on the intermediate transfer belt 6 to the recording material P. The recording material P with the toner image transferred is conveyed to the fixing device 11. The fixing device 11 fixes the toner image to the recording material P by heating and pressurizing the recording material P. After the toner image is fixed, the recording material P is discharged to the outside of the image forming apparatus 100.

[0016] The control unit 110 comprehensively controls the image forming operation of the image forming apparatus 100. The control unit 110 includes a CPU 111, a RAM 112, and a ROM 113. The ROM 113 is a non-volatile memory, and stores, for example, control programs and various data used in image formation. Note that the ROM 113 may be a rewritable non-volatile memory. The CPU 111 controls the image forming operation by executing the control program stored in the ROM 113. At that time, the CPU 111 uses various data stored in the ROM 113 and uses the RAM 112 as a work area. The control unit 110 generates and updates a tone correction table (LUT), which is correction information, by executing calibration described later. Then, the printer control unit 109 performs tone correction on the image data received from the image reading unit A or an external device using the LUT, and outputs an image signal based on the tone-corrected image data to the exposure device 3 to perform image formation.

[0017] The operation unit 20 includes a touch display 218 and provides a user interface. The user can operate the image forming apparatus 100 by inputting user input to the image forming apparatus 100 via the touch display 218. That is, the operation unit 20 functions as a reception unit for user input by the user. Also, the user can determine the state of the image forming apparatus 100 based on the screen displayed on the touch display 218.

[0018] The printer unit B may have a sensor 122 that detects the density of the toner image after fixing by the fixing device 11. The CPU 111 can detect the density of the toner image formed on the recording material P based on the detection result of the sensor 122. Also, the image forming units PY, PM, PC, and PK each have a density sensor 12 that detects the density of the toner image formed on the photoreceptor 1. The density sensor 12 includes a light emitting element such as an LED and a light receiving element such as a photodiode (PD). The light receiving element is arranged to receive the light emitted by the light emitting element and specularly reflected by the photoreceptor 1. The density sensor 12 outputs a signal indicating the amount of light received by the light receiving element to the CPU 111.

[0019] Figure 2 shows the relationship between the density of the toner image formed on the photoreceptor 1 and the output of the density sensor 12. The control unit 110 stores information for each color showing the relationship between the density of the toner image on the photoreceptor 1 and the output of the density sensor 12, as shown in Figure 2. Therefore, the CPU 111 can determine the density of the toner image formed on the photoreceptor 1 based on the output of the density sensor 12.

[0020] As described above, the image forming apparatus 100 performs calibration so that the density of the image to be formed approaches the target density. In this embodiment, calibration is classified into a first type of calibration and a second type of calibration. The first type of calibration is performed by forming a test pattern on the recording material P and detecting the test pattern formed on the recording material P with a sensor 122 or an image reading unit A. The second type of calibration is performed by forming a test pattern on the photoreceptor 1 and detecting the test pattern formed on the photoreceptor 1 with a density sensor 12. Figure 3 is a flowchart of the first type of calibration.

[0021] When a user instructs, for example, via the operation unit 20, to perform a first type of calibration, the control unit 110 forms a first test pattern on the recording material P in S10. The first test pattern includes multiple grayscale patch images for each color. For example, the first test pattern includes 64 different grayscale patch images for each color. In S11, the control unit 110 detects the density of each patch image of the first test pattern formed on the recording material P. For example, the density of each patch image of the first test pattern is detected by the image reading unit A reading each patch image of the first test pattern. In this case, the user sets the recording material P on which the first test pattern output by the image forming apparatus 100 has been formed into the image reading unit A and instructs the image forming apparatus 100 to read the recording material P via the operation unit 20. Alternatively, for example, the density of each patch image of the first test pattern can be detected by the sensor 122. In this case, the image forming apparatus 100 detects the density of each patch image of the first test pattern downstream of the fixing device 11.

[0022] In S12, the control unit 110 generates a LUT for each color based on the gradation value and detected density of each patch image, and the first target density corresponding to the gradation value of each patch image. The first target density is stored in the control unit 110 in advance. Figure 4 shows the relationship between the detected density, the first target density, and the generated LUT. The LUT is used to convert the gradation value (input gradation value) shown by the image data received from the image reading unit A or an external device during image formation to obtain the gradation value (output gradation value) used for image formation. By converting the gradation value shown by the image data using the LUT, the density of the image formed on the recording material P can be brought closer to the first target density.

[0023] Next, in S13 to S15, the control unit 110 performs a process to determine the second target density in the second type of calibration. First, in S13, the control unit 110 forms a second test pattern on each photoreceptor 1 using a plurality of different predetermined gradation values. In this example, the control unit 110 forms the second test pattern on each photoreceptor 1 using five different gradation values. In forming the second test pattern in S13, the control unit 110 uses the LUT generated in S12. That is, the control unit 110 converts the five predetermined gradation values ​​with the LUT and forms a second test pattern containing five patch images on each photoreceptor 1 based on the five converted gradation values. In S14, the control unit 110 uses each density sensor 12 to detect the density of each patch image of the second test pattern formed on each photoreceptor 1. The patch images of the second test pattern are transferred to the recording material P and fixed to become a patch image of the first target density. Therefore, the density detected by the density sensor 12 of the second test pattern in S14 is the density in the photoreceptor 1, with the density in the recording material P being the first target density. Accordingly, in S15, the control unit 110 stores the detected density of the patch image in S14 as the second target density of the gradation value (before conversion by LUT) used to form the patch image, for example, in RAM 112.

[0024] Figure 5 shows a specific example of the processing in S13-S15. In Figure 5, a second test pattern containing five patch images is formed on the photoreceptor 1 using five tonal values ​​48, 96, 144, 192, and 255. The detected densities by the density sensor 12 of the patch images formed with tonal values ​​48, 96, 144, 192, and 255 are D#1, D#2, D#3, D#4, and D5, respectively. In this case, the second target densities of the images formed on the photoreceptor 1 with tonal values ​​48, 96, 144, 192, and 255 are D#1, D#2, D#3, D#4, and D#5, respectively.

[0025] The image forming apparatus 100 then performs a second type of calibration when predetermined conditions are met. Specifically, a second test pattern is formed on each photoreceptor 1, and the density of each patch image of the second test pattern is detected by the density sensor 12. The LUT is then corrected so that the density of each patch image of the second test pattern approaches the second target density. In this way, a LUT is created in the first type of calibration, and the second target density is determined in the second type of calibration. The LUT is then updated in the second type of calibration. This makes it possible to bring the density of the image formed on the recording material P closer to the first target density.

[0026] However, as mentioned above, a LUT needs to be generated for each image forming mode. For example, the image forming apparatus 100 varies the process speed (such as the transport speed of the recording material P or the rotation speed of the photoreceptor 1) depending on the type of recording material P to be image formed. Therefore, if the image forming apparatus 100 uses multiple process speeds depending on the type of recording material P, it is necessary to create a LUT associated with each process speed. Similarly, if the image forming apparatus 100 uses multiple different resolutions, it is necessary to create a LUT associated with each resolution. Furthermore, if the image forming apparatus 100 uses multiple different types of halftone processing, it is necessary to create a LUT associated with each type of halftone processing.

[0027] Therefore, in this embodiment, the first type of calibration is provided with two modes: a first mode and a second mode. In the second mode, the user specifies the image formation mode for creating the LUT. On the other hand, in the first mode, calibration is performed using one predetermined image formation mode from among multiple image formation modes, and the user does not specify an image formation mode. Hereinafter, for the sake of simplicity, the first type of calibration performed in the first mode will also be referred to as "first calibration," and the first type of calibration performed in the second mode will also be referred to as "second calibration."

[0028] In the following description, as a specific example that does not limit the invention, the image forming modes are distinguished by process speed, and the image forming apparatus 100 has two process speeds: standard speed and low speed. The standard speed is used for the first type of recording material P, and the low speed is used for the second type of recording material P. Furthermore, for simplification of notation, the first type of recording material P will be referred to as "plain paper," and the second type of recording material P will be referred to as "cardboard."

[0029] <Second Calibration> For example, when a user instructs the operation unit 20 to perform the second calibration, the control unit 110 displays a screen on the touch display 218 of the operation unit 20 as shown in Figure 6. Based on the screen shown in Figure 6, the user selects either plain paper or cardboard as the recording material P to be used for the second calibration. This corresponds to specifying the image formation mode for the second calibration. For example, if the user selects plain paper, the control unit 110 displays the screen shown in Figure 7(A) on the touch display 218. When the user presses the "Start" button on the screen in Figure 7(A), the control unit 110 performs the second calibration at standard speed according to the flowchart in Figure 3. That is, the control unit 110 forms a first test pattern on plain paper to generate a LUT at standard speed and determines the second target density at standard speed.

[0030] On the other hand, when the user selects cardboard on the screen shown in Figure 6, the control unit 110 displays the screen shown in Figure 7(B) on the touch display 218. When the user presses the "Start" button on the screen in Figure 7(B), the control unit 110 performs a second calibration at low speed according to the flowchart in Figure 3. In other words, the control unit 110 forms a first test pattern on the cardboard to generate a low-speed LUT and determines the second target density at low speed. The first target density is the same regardless of the image formation mode (standard speed, low speed).

[0031] <First Calibration> In the first calibration, a first type of calibration is performed in a predetermined image formation mode to generate a LUT associated with that image formation mode and to determine a second target density for that image formation mode. Then, based on the LUT associated with the predetermined image formation mode, the LUTs and second target densities associated with each of the other image formation modes are determined. In the following description, the first calibration will be explained assuming that the predetermined image formation mode is a standard speed corresponding to plain paper. When the user instructs the execution of the first calibration via the operation unit 20, the control unit 110 displays a screen as shown in Figure 8 on the touch display 218 of the operation unit 20. When the user presses the "Start" button on the screen shown in Figure 8, the control unit 110 executes the first calibration according to the flowchart in Figure 9.

[0032] The processing steps S20 to S24 in Figure 9 are the same as the processing steps S10 to S14 in Figure 3, which are performed using plain paper. In S25, the control unit 110 stores the detected density of each patch image of the second test pattern in S24 as the second target density at standard speed and the second target density at low speed (target value) in, for example, RAM 112. Even if the density in the photoreceptor 1 is the same, the density trend in the recording material P differs depending on the process speed, but the difference is not large, so in this embodiment, the density detected in S24 is treated as the second target density in all image formation modes.

[0033] Next, in S26, the control unit 110 forms a second test pattern on the photoreceptor 1 at a low speed, and in S27, the density sensor 12 detects the density of each patch image of the second test pattern. Subsequently, in S28, the control unit 110 generates a low-speed LUT based on the second target density at a low speed (determined in S25) and the detected density of each patch image of the second test pattern formed on the photoreceptor 1 at a low speed (detected in S27).

[0034] In this way, by performing calibration in one of the multiple image formation modes, it is possible to generate LUTs for one or more other image formation modes in addition to the LUT for that one image formation mode, and to determine the second target density. Therefore, the time required for calibration can be shortened.

[0035] For example, during the initial setup of the image forming apparatus 100, it is necessary to create LUTs for each image forming mode for subsequent image forming. If the image forming apparatus 100 can only perform the second mode (second calibration), then the first type of calibration must be performed for each of the multiple image forming modes, increasing the workload of the setup process. Also, as in the above embodiment, if the image forming mode is related to the type of recording material P, then the recording material P related to each image forming mode (in the above embodiment, plain paper and cardboard) must be prepared in advance. On the other hand, the image forming apparatus 100 according to this embodiment is configured to be able to perform the first mode (first calibration). Therefore, by performing calibration in one image forming mode, LUTs for all image forming modes can be generated, reducing the workload during initial setup. Furthermore, it is not necessary to prepare all types of recording material P related to each image forming mode in advance.

[0036] In this embodiment, the operation unit 20 is configured to accept user input for performing a first calibration and user input for performing a second calibration. However, when certain conditions are met, such as during initial setup, the control unit 110 may configure the operation unit 20 to accept only user input for performing the first calibration. In other words, when these predetermined conditions are met, the control unit 110 of the image forming apparatus 100 may be configured to display the screen shown in Figure 8, but not the screen shown in Figure 6 on the operation unit 20. The predetermined conditions may be configured to be met when the first calibration has not been performed. The predetermined conditions may also be configured to be met when the control unit 110 does not have LUTs associated with each image forming mode stored. To illustrate with an example from the above embodiment, the predetermined conditions may be configured to be met when the control unit 110 does not have LUTs associated with standard speed and low speed stored.

[0037] Alternatively, the operation unit 20 can be configured to accept user input to perform a first type of calibration without distinguishing between the first and second calibrations. In this case, the control unit 110 performs the first calibration in response to user input if the predetermined conditions are met. On the other hand, if the predetermined conditions are not met, the control unit 110 displays a screen for user input to specify the image formation mode (Figure 6) on the operation unit 20 in response to user input, prompting the user to specify the image formation mode.

[0038] <Transformed form> In the flowchart shown in Figure 9, the density detected in S24 was used as the second target density for each of the multiple image formation modes. However, the density detected in S24 can be used as the second target density at standard speed, while the second target densities for other image formation modes, such as low speed, can be estimated and determined based on the density detected in S24. Figure 10 shows a modified version of the flowchart in Figure 9. Note that the same processing steps as in the flowchart in Figure 9 are assigned the same step numbers, and their explanations are omitted.

[0039] In S24, the control unit 110 detects the density of each patch image of the second test pattern formed at standard speed, and in S30, it stores the density detected in S24 as the second target density at standard speed. Subsequently, in S31, the control unit 110 determines and stores the second target density at low speed based on the second target density at standard speed. As an example, the control unit 110 determines the second target density at low speed by adjusting each of the second target densities at standard speed based on a pre-stored conversion coefficient. In this embodiment, the control unit 110 determines the second target density at low speed by multiplying the second target density at standard speed by a conversion coefficient. The conversion coefficient may be a predetermined value, but for example, as shown in Figure 11, it can be a different value for each condition. In Figure 11, the value of the conversion coefficient is varied based on the combination of temperature and humidity measured and detected by a thermometer and hygrometer (not shown) provided in the image forming apparatus 100. For example, according to Figure 11, the conversion coefficient is 1.03 when the temperature is 25 degrees and the humidity is 10%. Therefore, in this case, the second target concentration at low speed becomes the second target concentration obtained by multiplying the second target concentration at standard speed by 1.03. The conversion coefficient information shown in Figure 11 is stored in the control unit 110 in advance. In Figure 11, the conversion coefficient is determined based on a combination of temperature and humidity, but it is also possible to configure the system to determine the conversion coefficient based on only one of temperature or humidity. Furthermore, although the same conversion coefficient is used regardless of the grayscale value in Figure 11, it is also possible to configure the system to use different conversion coefficients depending on the grayscale value.

[0040] Even if the density in the photoreceptor 1 is the same, the density of the image formed on the recording material P may differ if the process speed (or the type of recording material P) is different. As mentioned above, although the density difference of the image formed on the recording material P is small, if there is a regularity in the relationship between the density in the photoreceptor 1 and the density in the recording material P, the second target density at low speeds can be accurately determined by using a conversion coefficient based on that regularity. Therefore, it is possible to accurately generate a LUT for an image formation mode different from the image formation mode used in the first calibration.

[0041] <Other> In the above embodiments, a LUT was generated for each process speed, and the process speed was determined based on the type of recording material P. For example, if the image forming apparatus 100 uses a first process speed for three types of recording material P and a second process speed for the other two types of recording material P, a LUT for the first process speed and a LUT for the second process speed were generated. However, it is also possible to have a configuration in which a LUT is generated for each type of recording material P regardless of the process speed. In other words, the image forming mode can be distinguished not by the process speed, but by the type of recording material P used to form the image.

[0042] Furthermore, the image formation mode can be distinguished by a combination of two or more of the following: process speed, resolution, halftone processing, and type of recording material P. For example, if two process speeds, low speed and standard speed, and two resolutions, low resolution and high resolution, are used, the number of image formation modes can be four.

[0043] [Other embodiments] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0044] This disclosure includes the following components: (Composition 1) Image forming means for forming an image on a recording material using correction information associated with an image forming mode based on image data, The first detection means detects the density of the image formed on the recording material by the image forming means, A reception means for receiving user input regarding whether to perform a first calibration or a second calibration, When performing the first calibration, the image forming means controls the image forming means to form a first test pattern on the recording material in a first image forming mode, generates first correction information associated with the first image forming mode based on the detection result of the first test pattern by the first detection means, and generates second correction information associated with the second image forming mode based on the first correction information; when performing the second calibration, the image forming means controls the image forming means to form the first test pattern on the recording material in an image forming mode specified by the user, and generates the correction information associated with the specified image forming mode based on the detection result of the first test pattern by the first detection means; The control means is configured such that, if the first calibration has not been performed, the receiving means accepts only the user input to perform the first calibration. (Configuration 2) Image forming means for forming an image on a recording material using correction information associated with an image forming mode based on image data, The first detection means detects the density of the image formed on the recording material by the image forming means, A reception means for receiving user input regarding whether to perform a first calibration or a second calibration, When performing the first calibration, the image forming means controls the image forming means to form a first test pattern on the recording material in a first image forming mode, generates first correction information associated with the first image forming mode based on the detection result of the first test pattern by the first detection means, and generates second correction information associated with the second image forming mode based on the first correction information; when performing the second calibration, the image forming means controls the image forming means to form the first test pattern on the recording material in an image forming mode specified by the user, and generates the correction information associated with the specified image forming mode based on the detection result of the first test pattern by the first detection means; Image forming apparatus, wherein the control means stores the first correction information and the second correction information generated in the first calibration, and the receiving means is configured to accept only the user input to perform the first calibration if the first correction information and the second correction information are not stored. (Composition 3) The image forming apparatus according to configuration 1 or 2, wherein the image forming mode is distinguished based on at least one of the type of recording material used to form the image, the resolution of the image, the process speed when forming the image, and the type of halftone processing performed when forming the image. (Composition 4) The image forming apparatus according to any one of configurations 1 to 3, wherein the correction information is a tone correction table for correcting the tone values ​​indicated by the image data. (Composition 5) The image forming means transfers the toner image formed on the image carrier to the recording material, and fixes the toner image transferred to the recording material to the recording material, thereby forming the image on the recording material. The image forming apparatus further comprises a second detection means for detecting the density of the toner image formed on the image carrier, An image forming apparatus according to any one of configurations 1 to 4, wherein in the first calibration, the control means controls the image forming means to form a second test pattern on the image carrier in the first image forming mode using the first correction information, determines a target value for the detection density of the second test pattern in the second image forming mode based on the detection result of the second test pattern formed in the first image forming mode by the second detection means, controls the image forming means to form a second test pattern on the image carrier in the second image forming mode, and generates the second correction information based on the detection result of the second test pattern formed in the second image forming mode by the second detection means and the target value for the detection density of the second test pattern in the second image forming mode. (Composition 6) The image forming apparatus according to configuration 6, wherein the control means determines the detection density of the second test pattern formed in the first image forming mode by the second detection means as the target value of the detection density of the second test pattern in the second image forming mode. (Composition 7) The image forming apparatus according to configuration 5, wherein the control means determines the target value of the detection density of the second test pattern in the second image forming mode by adjusting the detection density of the second test pattern formed in the first image forming mode by the second detection means based on a coefficient. (Composition 8) The image forming apparatus according to configuration 6, wherein the coefficient is determined based on at least one of the temperature and humidity measured by the image forming apparatus. [Explanation of symbols]

[0045] 109: Printer control unit, PY, PM, PC, PK: Image forming unit, 122: Sensor, A: Image reading unit, 110: Control unit

Claims

1. A conversion means for converting image data based on conversion conditions, Image forming means for forming an image on a recording material based on image data converted by the conversion means, A first detection means for detecting the image formed on the recording material by the image forming means, A control means, A first calibration that generates a first conversion condition used for forming an image at the first image formation speed, and a second conversion condition used for forming an image at a second image formation speed different from the first image formation speed, based on the detection result by the first detection means of a first test pattern formed by the image forming means at a first image formation speed, A second calibration that generates the second conversion condition used to form an image at the second image forming speed based on the detection result by the first detection means of the second test pattern formed by the image forming means at the second image forming speed, The control means that executes, A receiving means for receiving user instruction information that instructs the execution of calibration, Equipped with, If the first calibration has not been performed, the receiving means does not accept the user instruction information instructing the execution of the second calibration. The control means is characterized in that it does not perform the second calibration during initial setup of the image forming apparatus.

2. A conversion means for converting image data based on conversion conditions, Image forming means for forming an image on a recording material based on image data converted by the conversion means, A first detection means for detecting the image formed on the recording material by the image forming means, A control means, A first calibration that generates a first conversion condition used for forming an image at the first image formation speed, and a second conversion condition used for forming an image at a second image formation speed different from the first image formation speed, based on the detection result by the first detection means of a first test pattern formed by the image forming means at a first image formation speed, A second calibration that generates the second conversion condition used to form an image at the second image forming speed based on the detection result by the first detection means of the second test pattern formed by the image forming means at the second image forming speed, The control means that executes, A receiving means for receiving user instruction information that instructs the execution of calibration, Equipped with, If the second conversion condition has not been generated, the receiving means does not accept the user instruction information that instructs the execution of the second calibration. The control means is characterized in that it does not perform the second calibration during initial setup of the image forming apparatus.

3. The image forming apparatus according to claim 1 or 2, characterized in that the conversion conditions are a tone correction table for converting tone values ​​shown in the image data.

4. The image forming means transfers the toner image formed on the image carrier to the recording material, and fixes the toner image transferred to the recording material to the recording material, thereby forming the image on the recording material. The image forming apparatus further comprises a second detection means for detecting the density of the toner image formed on the image carrier, The image forming apparatus according to claim 1 or 2, characterized in that, in the first calibration, the control means controls the image forming means to form a third test pattern on the image carrier at a first image forming speed using the first conversion condition, determines a target value for the detection density of the third test pattern at a second image forming speed based on the detection result of the third test pattern formed at the first image forming speed by the second detection means, controls the image forming means to form the third test pattern on the image carrier at a second image forming speed, and generates a second conversion condition based on the detection result of the third test pattern formed at the second image forming speed by the second detection means and the target value for the detection density of the third test pattern at the second image forming speed.

5. The image forming apparatus according to claim 4, characterized in that the control means determines the detection density of the third test pattern formed at the first image forming speed by the second detection means as the target value of the detection density of the third test pattern at the second image forming speed.

6. The image forming apparatus according to claim 4, characterized in that the control means determines the target value of the detection density of the third test pattern at the second image forming speed by adjusting the detection density of the third test pattern formed at the first image forming speed by the second detection means based on a coefficient.

7. The image forming apparatus according to claim 6, characterized in that the coefficient is determined based on the temperature measured by the image forming apparatus.

8. The image forming apparatus according to claim 6, characterized in that the coefficient is determined based on the humidity measured by the image forming apparatus.

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