JP5707379B2 - Image forming apparatus and program - Google Patents

Description

  Embodiments described herein relate generally to an image forming apparatus and a program for forming an image on a recording medium.

  In general, an image forming apparatus such as a printer or a multifunction peripheral (MFP) has a function of performing a paper-based calibration in order to eliminate density fluctuations and color balance deterioration due to aging of a print engine. . In this calibration, the image forming apparatus generates tone correction data for correcting the tone characteristics of the print engine based on density information obtained by printing the patch image on a sheet and reading the patch image with a scanner or the like. To do.

  Further, after calibration on a paper base, a patch image is formed on an image carrier such as a transfer belt at a timing when the total number of sheets passed becomes a predetermined number, and density information of the patch image is detected and detected. Some image forming apparatuses have a function of updating gradation correction data so that a change in gradation characteristics with time is absorbed based on density information.

  Since the gradation characteristics of the print engine are determined for each of various types of paper, existing image forming apparatuses execute the above-described paper-based calibration and subsequent processing for each paper type. ing.

  When the above-described paper-based calibration and processing relating to subsequent updates are executed for each paper, there is a problem that the processing takes a long time.

JP 2009-230144 A

  The problem to be solved by the present invention is to reduce the time required for correcting the gradation characteristics of the print engine provided in the image forming apparatus.

An image forming apparatus according to an embodiment includes a print engine, a sensor, a memory, a controller, and an operation unit .
The print engine forms a toner image corresponding to the image information on the image carrier and transfers the toner image to a recording medium. The sensor detects the density of the toner image formed on the image carrier. The memory stores gradation correction data for correcting the gradation characteristics of the print engine for each type of recording medium. The controller causes the print engine to form a patch image on the image carrier based on the gradation characteristics of a specific type of recording medium, and to determine the density of the patch image detected by the sensor and the specific A first update process for updating the gradation correction data of various recording media stored in the memory based on the density of the patch image transferred to the type of recording medium, and the print engine. Based on the gradation characteristics of the specific type of recording medium, a patch image is formed on the image carrier, and the density of the patch image detected by the sensor and the first update process A second update for updating the gradation correction data of various recording media stored in the memory based on the density of the patch image detected by the sensor The execution and management, the. In the first update process or the second update process, the operation unit collectively performs the tone correction on the recording medium of the type selected from the recording media for each type. Either a common mode in which data is updated or a mode for each recording medium in which the gradation correction data is individually updated for the recording medium for each type is received.
The operation unit enables the setting of the common mode or the recording medium mode for each recording medium of the type,
When the common mode is set by the operation unit, the controller collectively selects the recording media for the selected types of the recording media in the first update process or the second update process. When the tone correction data is updated and a mode for each recording medium is set, the gradation correction is individually performed for the recording medium for each type in the first update process or the second update process. Update the data .

1 is a block diagram showing a main configuration of an image forming apparatus according to an embodiment. 2 is a diagram for explaining a controller and a print engine of the image forming apparatus. FIG. FIG. 3 is a diagram illustrating an example of a patch image formed by the image forming apparatus. FIG. 3 is a diagram for explaining a first update process executed by the image forming apparatus. 6 is a flowchart for explaining a second update process executed by the image forming apparatus.

  An embodiment will be described with reference to the drawings.

FIG. 1 is a block diagram illustrating a main configuration of an image forming apparatus 1 according to the present embodiment.
The image forming apparatus 1 is, for example, an MFP, and includes a controller 2, a communication device 3, a scanner 4, a paper feed cassette 5, a print engine 6, and an operation panel 7.

  The controller 2 executes various processes for controlling the operation of the image forming apparatus 1. The processing by the controller 2 may be realized by software by executing a computer program on a processor, or may be realized by hardware by combining various circuits.

  The communication device 3 transmits / receives image data and various commands to / from an external device such as a personal computer or a server device that is connected to the image forming device 1 by wire or wirelessly. Output to 2.

  The scanner 4 optically scans a recording medium such as paper to generate image data, and outputs the generated image data to the controller 2.

  The paper feed cassette 5 stores paper that is a recording medium, and supplies the paper to the print engine 6 in accordance with an instruction from the controller 2. The image forming apparatus 1 may include only one sheet feeding cassette 5 or a plurality of sheet feeding cassettes 5. The paper feed cassette 5 stores paper of a type such as “plain paper”, “recycled paper”, “special paper”, “thick paper”, for example. Note that the image forming apparatus 1 may include a manual paper feed mechanism that takes in paper that is manually fed by the user and supplies the paper to the print engine 6 as means for supplying paper to the print engine 6.

  The print engine 6 forms an image based on the image data received by the communication device 3 or the image data generated by the scanner 4 on the paper supplied from the paper feed cassette 5.

  The operation panel 7 includes operation buttons for inputting various instructions, a display with a touch panel, and the like.

Details of the controller 2 and the print engine 6 will be described with reference to FIG.
The print engine 6 is a print engine that performs electrophotographic printing, and includes a print unit 60, a transfer belt 61, a power supply roller 62, a driven roller 63, a fixing device 64, and a toner adhesion amount sensor 65. . In particular, in the present embodiment, the print engine 6 corresponds to color printing, and forms images with yellow (Y), magenta (M), cyan (C), and black (K) developers (toners), respectively. Four printing units 60Y, 60M, 60C, and 60K are provided.

  The printing units 60Y, 60M, 60C, and 60K are a photosensitive drum as an image carrier, a charger that uniformly charges the photosensitive drum, and image data to be printed by exposing the charged photosensitive drum. And an exposure device that forms an electrostatic latent image corresponding to the electrostatic latent image, and selectively attaching toner to the photosensitive drum corresponding to the electrostatic latent image to visualize the electrostatic latent image as a reversed toner image A toner image on the photosensitive drum is transferred to the transfer belt 61. Further, the printing units 60Y, 60M, 60C, and 60K include a cleaning device that removes toner remaining on the photosensitive drum after transfer to the transfer belt 61 and a static eliminator that neutralizes the surface of the photosensitive drum.

  The transfer belt 61 is an intermediate image carrier that is stretched between the power supply roller 62 and the driven roller 63 and rotates in the direction of the arrow in FIG. The transfer belt 61 conveys the paper P supplied from the paper feed cassette 5 to the print engine 6 while being in contact with the lower surface. The power supply roller 62 rotates by being driven by a motor (not shown) and receives a bias voltage having a polarity opposite to the charging polarity of the toner. As described above, the toner images formed on the photosensitive drums of the printing units 60Y, 60M, 60C, and 60K are transferred to the transfer belt 61 by the action of the power supply roller 62. The transfer belt 61 transfers the toner image transferred from each photosensitive drum to the paper P. The fixing device 64 fixes the toner image transferred to the paper P to the paper P, and discharges the paper P after fixing to a paper discharge unit (not shown).

  The toner adhesion amount sensor 65 detects the density (toner adhesion amount) of a patch image, which is a test toner image transferred from the photosensitive drums of the print units 60Y, 60M, 60C, and 60K to the transfer belt 61.

  The controller 2 includes an image processing device 20, a patch image generation device 21, a storage device 22, and a correction amount calculation device 23. Each of these devices may be realized by software by executing a computer program stored in a memory by a processor included in the controller 2, or may be realized by hardware by combining various circuits.

  The image processing device 20 controls the print engine 6 to form an image on the paper P according to the image data input from the communication device 3 or the scanner 4 to the controller 2. The image processing apparatus 20 includes a memory 24 that stores image forming conditions including gradation characteristic data when the printing units 60Y, 60M, 60C, and 60K form toner images on the transfer belt 61. For example, the gradation characteristic data is a development contrast voltage applied to the photosensitive drum when the photosensitive drum is charged in each of gradations divided into 0 to 255. However, the gradation characteristic data may be other parameters that determine the gradation of the toner image. The memory 24 stores such gradation characteristic data in advance for each of the printing units 60Y, 60M, 60C, and 60K and for each type of paper P. Further, the memory 24 stores gradation correction data T for correcting a change in gradation characteristics of the print engine 6 with time for each of the print units 60Y, 60M, 60C, and 60K and for each type of the paper P. When forming an image, the image processing apparatus 20 controls the print engine 6 under the image forming conditions in which the gradation characteristic data is corrected by the gradation correction data T, and forms an image on the paper P.

  The patch image generating device 21 controls the print engine 6 to form a patch image on the transfer belt 61 according to the gradation characteristic data stored in the memory 24. An example of the patch image is shown in FIG. This figure shows an example in which seven patch images 100, 101, 102, 103, 104, 105, 106 having different gradations are formed on the transfer belt 61 within the gradation range indicated by the gradation characteristic data described above. ing. For example, when the gradation range is 0 to 255, the patch image 100 corresponds to 0 (white), which is the minimum gradation value, and the patch image 106 corresponds to 255 (solid), which is the maximum gradation value. The patch images 101 to 105 may correspond to gradation values that divide the range of 0 to 255 at equal intervals. The patch image generating device 21 forms such a row of patch images 100 to 106 in each of the print units 60Y, 60M, 60C, and 60K.

  The toner adhesion amount sensor 65 detects the density of each patch image formed on the transfer belt 61. The storage device 22 stores sensor gradation value data composed of the densities of the respective patch images detected by the toner adhesion amount sensor 65 and correction mode data described later.

  The correction amount calculation device 23 calculates the gradation correction data T based on the sensor gradation value data and the correction mode data stored in the storage device 22, and the memory 24 already stores the calculated gradation correction data T. The gradation correction data T is updated. The processing relating to the update of the gradation correction data T includes paper-based calibration (first update processing) using image data obtained by scanning the patch image formed on the paper P with the scanner 4, and the paper. This can be broadly divided into update processing (second update processing) that does not involve the formation of patch images on P.

  Hereinafter, the first and second update processes will be described. In this embodiment, 10 types such as “plain paper”, “recycled paper”, “special paper”, and “thick paper” are used as the paper types for which the gradation correction data T should be updated in the first and second update processes. Assume that there are several types of paper. In the following description, each type of paper is represented by a type number i (i = 0 to 9). Further, in the following description, for simplification of description, processing for any one of the print units 60Y, 60M, 60C, and 60K is shown, but the image forming apparatus 1 also applies to the other three print units. A similar process is executed.

[First update process]
First, the first update process, that is, paper-based calibration will be described. In the description, the setting examples of the parameters (correction mode data C [i], sensor gradation value data SA [i], gradation correction data T [i]) shown in FIG. 4 will be referred to as appropriate.
The controller 2 starts the process in response to, for example, the user operating the operation panel 7 and instructing the start of the first update process. At the beginning of the start, first, the controller 2 accepts the setting of either the common mode or the sheet-specific mode for each of the sheets related to the type number i (i = 0 to 9) as the first update processing mode to be executed. . The user performs the setting by operating the operation panel 7, for example. The controller 2 sets the correction mode data C [i] stored in the storage device 22 to “1” for the data corresponding to the type number i for which the common mode is selected, and the type number for which the paper-specific mode is selected. For those corresponding to i, “2” is set. In the example of FIG. 4, the common mode is set for the classification numbers i = 0 to 7, and the sheet-specific mode is set for the classification numbers i = 8 and 9. Therefore, the correction mode data C [0] to C [7] are “1”, and the correction mode data C [8] and C [9] are “2”.

  After such mode setting, the patch image generating device 21 sets the type number i having the correction mode data C [i] “1” to the smallest value (i = 0 in the example of FIG. 4). A patch image based on the gradation characteristic data of the corresponding paper is formed on the transfer belt 61. The toner adhesion amount sensor 65 detects the density of these patch images and outputs the detected density to the storage device 22. The storage device 22 outputs sensor gradation value data composed of the density of the patch image input from the toner adhesion amount sensor 65 to the first corresponding to the type number i whose correction mode data C [i] is “1”. Is stored as sensor gradation value data SA [i]. The print engine 6 transfers the patch image formed on the transfer belt 61 to a sheet corresponding to the used gradation characteristic data, and discharges it to a discharge unit (not shown). The user inputs the image data of each patch image to the correction amount calculation device 23 by, for example, scanning this sheet with the scanner 4. The correction amount calculation device 23 calculates the first density of the type number i having the smallest value among the density of the patch image measured from the image data and the type number i whose correction mode data C [i] is “1”. Based on the sensor gradation value data SA [i], gradation correction data T [i] for correcting the gradation characteristic data of the paper relating to the classification number i is calculated. The correction amount calculation device 23 uses the calculated gradation correction data T [i] and the gradation corresponding to each of the classification numbers i whose correction mode data C [i] already stored in the memory 24 is “1”. The correction data T [i] is updated.

  For example, in the example of FIG. 4, the first sensor gradation value data SA [0] relating to the sheet of the type number i = 0 having the smallest value among the type numbers i whose correction mode data C [i] is “1”. ], “SA0” is obtained. In this case, the storage device 22 stores “SA0” as the first sensor gradation value data SA [0] to SA [7] relating to the sheet of the type number i = 0 to 7. Furthermore, it is assumed that the correction amount calculation device 23 calculates “T0” as the gradation correction data T [0] relating to the paper of the type number i = 0. In this case, the correction amount calculation device 23 updates the gradation correction data T [0] to T [7] relating to the sheet of the type number i = 0 to 7 stored in the memory 24 to “T0”.

  As described above, the controller 2 obtains the first sensor gradation value data SA [i] for any one sheet and the gradation correction data T [i] for the sheet of the type number i for which the common mode is set. And the result is copied to the first sensor gradation value data SA [i] and gradation correction data T [i] for the remaining paper.

  On the other hand, the controller 2 forms the patch image and detects the density of the patch image (acquisition / storage of the first sensor gradation value data SA [i]) for the sheet of the type number i for which the sheet mode is set. The gradation correction data T [i] is calculated and updated separately. For example, in the example of FIG. 4, the controller 2 forms a patch image, detects the density of the patch image, and detects the gradation for each sheet of the classification numbers 8 and 9 whose correction mode data C [i] is “2”. The correction data T [i] is calculated and updated individually.

[Second update process]
Next, the second update process will be described.
When a predetermined activation condition is satisfied, the image forming apparatus 1 executes a second update process. As the activation condition, for example, it is possible to adopt that the cumulative number of sheets passed reaches a specified number (for example, 1000 sheets) or that a predetermined time has arrived.

  FIG. 5 is a flowchart showing the operation of the image forming apparatus 1 in the second update process. Hereinafter, it demonstrates along this flowchart.

  At the beginning of the process, the controller 2 first forms a counter i in its own RAM and resets its value to “0” (Act 1). Further, the controller 2 forms the calculated flag F in the RAM and resets the value to “0” (Act 2).

  Subsequently, the controller 2 determines whether or not the correction mode data C [i] = 1 (Act 3). When the correction mode data C [i] = 1 (Yes in Act3), the controller 2 determines whether the calculated flag F = 1 is satisfied (Act4).

  When the calculated flag F is not 1 (No in Act 4), the patch image generating device 21 transfers a patch image based on the gradation characteristic data of the sheet having the same type number i as the current counter i as an intermediate image carrier. The belt 61 is formed (Act 5). Further, the toner adhesion amount sensor 65 detects the density of the patch image, and outputs the detected density to the storage device 22 (Act 6). The storage device 22 stores sensor tone value data including the density of the patch image input from the toner adhesion amount sensor 65 as second sensor tone value data SB [i].

  Subsequently, the correction amount calculation device 23 updates the gradation correction data T [i] related to the type number i having the same value as the current counter i (Act 7). Specifically, the correction amount calculation device 23 first converts the first sensor gradation value data SA [i] stored in the storage device 22 into physical amount data representing a physical amount such as brightness, and inversely converts it into the physical amount data. By performing the processing, target gradation data is calculated. The correction amount calculation device 23 converts the second sensor gradation value data SB [i] stored in the storage device 22 into physical amount data representing a physical amount such as brightness, and performs an inverse conversion process on the physical amount data. Thus, the correction target gradation data is calculated. Thereafter, the correction amount calculation device 23 changes the gradation characteristics of the print engine 6 over time from the time when the first update process is executed to the present based on the calculated target gradation data and correction target gradation data. The tone correction data (automatic tone correction data) representing is calculated. Finally, the correction amount calculation device 23 combines the calculated automatic gradation correction data and the gradation correction data T [i] stored in the memory 24 to obtain final gradation correction data T [i]. The gradation correction data T [i] in the memory 24 is updated with the calculated gradation correction data T [i].

  After Act7, the controller 2 sets the calculated flag F to “1”, forms a variable paper in the RAM, and sets the variable paper to the value of the counter i (Act8). Further, the controller 2 determines whether or not the counter i is less than PAPER-NUM-1 obtained by dividing 1 from PAPER-NUM representing the number of paper types (Act 9). In the present embodiment, PAPER-NUM = 10.

  When the counter i is less than PAPER-NUM-1 (Yes in Act 9), the controller 2 increments the counter i by 1 (Act 10). Thereafter, the operation returns to Act3.

  In Act 4 after Acts 5 to 8 are executed once, the controller 2 determines that the calculated flag F = 1 is satisfied (Yes in Act 4). In this case, the correction amount calculation device 23 uses the gradation correction data T [i] corresponding to the current value of the counter i stored in the memory 24 and the gradation correction data T [i] corresponding to the variable paper stored in the memory 24. paper]] (Act 11). Thereafter, the operation moves to Act9.

  If the correction mode data C [i] is not 1 in Act3, in other words, if the correction mode data C [i] = 2 (No in Act3), the controller 2 operates along Acts 12-14. That is, first, the patch image generating device 21 forms a patch image on the transfer belt 61 as an intermediate image carrier based on the gradation characteristic data of the sheet having the same type number i as the current counter i (Act 12). Further, the toner adhesion amount sensor 65 detects the density of the patch image, and outputs the detected density to the storage device 22 (Act 13). The storage device 22 stores sensor tone value data including the density of the patch image input from the toner adhesion amount sensor 65 as second sensor tone value data SB [i]. Subsequently, the correction amount calculation device 23 updates the gradation correction data T [i] related to the type number i having the same value as the current counter i (Act 14). The update flow in Act14 is the same as in Act7. After Act14, the operation moves to Act9.

  When the counter i eventually reaches PAPER-NUM-1 (No in Act 9), the second update process is completed.

  A specific example of the second update process will be described using the case where the correction mode data C [i] is set as shown in FIG. 4 in the first update process. Since the correction mode data C [0] = 1 in the state of the counter i = 0 at the beginning of the processing, the operation of the image forming apparatus 1 returns to Act 3 via Acts 3 to 10. At this time, the controller 2 calculates the gradation correction data T [0] related to the paper of the type number i = 0, and updates the gradation correction data T [0] stored in the memory 24. Further, the controller 2 sets the calculated flag F to “1” and sets the value “0” of the counter i to the variable paper. Subsequently, in the state of the counter i = 1, the correction mode data C [1] = 1, but the calculated flag F = 1. Therefore, the controller executes Act11 and the gradation correction stored in the memory 24 is stored. Data T [1] is updated with gradation correction data T [0] corresponding to variable paper (= 0). The correction mode data C [2] to C [7] = 1 for the paper with the classification number i = 2 to 7. Therefore, during the counter i = 2 to 7, the controller 2 repeatedly executes Act11, and the gradation correction data T [2] to T [7] stored in the memory 24 corresponds to the gradation corresponding to the variable paper (= 0). Update with correction data T [0]. The correction mode data C [8], C [9] = 2 for the paper of the classification number i = 8,9. Therefore, during the counter i = 8, 9, the image forming apparatus 1 repeatedly executes Acts 12 to 14 to calculate the gradation correction data T [8], T [9] relating to the paper of the type number i = 8, 9. Then, the gradation correction data T [8] and [9] stored in the memory 24 are updated. In this way, the gradation correction data T [i] for each sheet is updated.

  As described above, the image forming apparatus 1 according to the present embodiment obtains gradation correction data for any one sheet in the first and second update processes for the type of sheet for which the common mode is set. The gradation correction data is also used for other sheets for which the common mode is set. In this way, the time required for correcting the gradation characteristics can be shortened. In particular, when the image forming apparatus 1 includes four print units 60Y, 60M, 60C, and 60K, it takes a lot of time to update the gradation correction data for each of the print units 60Y, 60M, 60C, and 60K. In view of the necessity, the use of the common mode leads to a significant time reduction in the update process.

Further, the image forming apparatus 1 individually updates the gradation correction data in the first and second update processes for the type of paper for which the paper mode is set. That is, the common setting and the individual setting can be properly used for each sheet according to the situation.
In addition to these, various suitable effects can be obtained from the configuration disclosed in the present embodiment.

The configuration disclosed in the present embodiment can be modified in various ways.
For example, the image forming apparatus 1 is not limited to the one including the four print units 60Y, 60M, 60C, and 60K, and may include only one print unit 60.

  In the above embodiment, an example in which the common mode and the individual paper mode are individually set for each paper has been shown. However, when the common mode is set by a specific operation, all the papers are shared at once. When the update process is performed in the mode and the sheet mode is set by a specific operation, all sheets may be updated in the sheet mode at once.

  In the above embodiment, the computer program for realizing the first update process and the second update process is stored in the image forming apparatus 1 in advance. However, the present invention is not limited to this, and a similar program may be downloaded from the network to the image forming apparatus 1. Alternatively, a similar program recorded on the recording medium may be installed in the image forming apparatus 1. The recording medium may be in any form as long as it can store a program such as a CD-ROM or a memory card and can be read by the apparatus. Further, the function obtained by installing or downloading the program may be realized in cooperation with the OS (operating system) of the image forming apparatus 1 or the like.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Controller, 3 ... Communication apparatus, 4 ... Scanner, 5 ... Paper feed cassette, 6 ... Print engine, 7 ... Operation panel, 20 ... Image processing apparatus, 21 ... Patch image generator, 22 ... Storage device 23 ... Correction amount calculation device 24 ... Memory 60 (60Y, 60M, 60C, 60K) ... Print section 61 ... Transfer belt (image carrier), 62 ... Feed roller, 63 ... Driven roller, 64 ... Fixing device, 65 ... toner adhesion amount sensor.

Claims (5)

A print engine for forming a toner image corresponding to image information on an image carrier and transferring the toner image to a recording medium;
A sensor for detecting a density of a toner image formed on the image carrier;
A memory for storing gradation correction data for correcting gradation characteristics of the print engine for each type of recording medium;
The print engine forms a patch image on the image carrier based on the gradation characteristics of a specific type of recording medium, and the density of the patch image detected by the sensor and the specific type of recording medium. A first update process for updating the gradation correction data of various recording media stored in the memory based on the density of the patch image transferred to the recording medium; Based on the gradation characteristics of the type of recording medium, a patch image is formed on the image carrier, and the sensor detects the density of the patch image detected by the sensor and the first update process. And a second update process for updating the gradation correction data of various recording media stored in the memory based on the density of the patch image that has been performed. And a controller,
In the first update process or the second update process, the gradation correction data is updated collectively for the selected recording medium of the type among the recording media for each type. An operation unit that accepts a setting of a mode or a mode for each recording medium that individually updates the gradation correction data for the recording medium for each type;
Equipped with a,
The operation unit enables the setting of the common mode or the recording medium mode for each recording medium of the type,
When the common mode is set by the operation unit, the controller collectively selects the recording media for the selected types of the recording media in the first update process or the second update process. When the tone correction data is updated and a mode for each recording medium is set, the gradation correction is individually performed for the recording medium for each type in the first update process or the second update process. Update data,
An image forming apparatus. The controller includes a form of the case where the gradation correction data to be updated individually setting a recording medium different mode is performed, the patch image to the image bearing member in the first updating process, Proceed separately for the recording medium of said updating of said gradation correction data based on the density of the transferred the patch image to the patch image and the recording medium was the formation type, the in the second updating process the formation of the patch image to the image carrier, the of the formed patch image density and the first of the tone correction data based on the concentration of the patch image obtained by the updating process updates and the said type The image forming apparatus according to claim 1, wherein the image forming apparatus is executed individually for a recording medium. The print engine includes a plurality of printing portion forming the patch images corresponding to each of a plurality of different colors from each other on the image bearing member,
The image forming apparatus according to claim 1, wherein the controller executes the first update process and the second update process for each of the plurality of print units. Forming a toner image corresponding to the image information on an image carrier, and the print engine for transferring the toner image on a recording medium, and a sensor for detecting the concentration of the toner image formed on the image bearing member, memory and, the recording medium of said selected type of the recording medium for each of the type that stores tone correction data for correcting the gradation characteristics of the print engine for each type of the recording medium The setting of either the common mode for updating the gradation correction data in batch or the mode for each recording medium for updating the gradation correction data individually for the recording medium for each type is accepted. A controller of an image forming apparatus including an operation unit ;
The print engine forms a patch image on the image carrier based on the gradation characteristics of a specific type of recording medium, and the density of the patch image detected by the sensor and the specific type of recording medium. A function of executing a first update process for updating the gradation correction data of various recording media stored in the memory based on the density of the patch image transferred to the recording medium;
Causing the print engine to form a patch image on the image carrier based on the gradation characteristics of the recording medium of the specific type, and the density and the first update of the patch image detected by the sensor; A function of executing a second update process for updating the gradation correction data of various recording media stored in the memory based on the density of the patch image detected by the sensor in the process;
Including
When the common mode is set by the operation unit, the controller collectively collects the recording medium for each of the selected types in the first update process or the second update process. A function to update gradation correction data;
When the mode for each recording medium is set, in the first update process or the second update process, the function of updating the gradation correction data individually for the recording medium for each type;
A program to realize The controller of the image forming apparatus, when the setting to the effect that updated separately the gradation correction data has been made, the formation of the patch image to the image bearing member in the first update process, the formation said gradation correction data updating executed separately for the recording medium of the type, the image bearing member in the second updating process based on the concentration of the patch image transferred to the patch image and the recording medium was the formation of patch images to, for the concentration and the first based on the concentration of the patch image obtained by updating the tone correction recording medium of the data updates and the type of patch images the form The program according to claim 4 for further realizing the function to be executed individually.

Images