Image forming apparatus, image forming method and program

Abstract

To allow for appropriately adjusting color tone of images according to the capacity of a toner container.SOLUTION: An image forming device provided herein is configured to acquire information indicative of the capacity of a toner container, determine a gamma table for correcting brightness of an image to be printed according to the acquired information, and correct the brightness of the image using the determined gamma table.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] Some laser beam image forming devices are replaceable as a single cartridge, integrating consumables such as toner, a toner container containing the toner, a developer, and a photosensitive drum. For a single image forming device, multiple cartridges are available, including small-capacity, medium-capacity, and large-capacity toner containers, depending on the user's needs. For a large-capacity toner container, the photosensitive drum integrated into the cartridge must have a thicker film thickness to withstand long-term wear, considering the cartridge's lifespan. A thicker photosensitive drum causes the potential on the photosensitive drum surface to decay differently when irradiated with laser light than a normal film thickness, resulting in differences in the amount of toner adhered per dot. Such differences in toner adherence result in differences in the color density that can be reproduced with the same number of dots, resulting in variations in the reproducibility of intermediate densities (halftones). Furthermore, because photosensitive drums with different film thicknesses are used depending on the capacity of the toner container, variations in the reproducibility of intermediate densities occur not only when the toner container is large, but also when the toner container is small or medium.

[0003] Regarding the adjustment of color density for each cartridge, Patent Document 1 discloses the following technology: That is, Patent Document 1 discloses a technology for reading information about the coloring degree (parameter) of the toner contained in a toner container from an ID chip installed in the toner container, and adjusting the amount of toner adhesion in a toner image formed on a photosensitive drum according to the read information. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-134060 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology in Patent Document 1 is based on the premise that the color of toner stored in each toner container is different. Therefore, even if the toner color is the same for each toner container but the capacity of the toner containers is different, only information indicating the color intensity corresponding to each color of toner can be referenced, and the color of the image used in the printing process cannot be appropriately adjusted.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and is a first capacity, a first gamma table is determined, and when the capacity of the toner container is a second capacity greater than the first capacity, a second gamma table is determined in which an output luminance value for a certain input luminance value is greater than that of the first gamma table, and the luminance value of the image is corrected using the determined gamma table. We provide the technology to do this. [Means for solving the problem]

[0007] An image forming apparatus according to an aspect of the present disclosure 、 the image forming apparatus has Toner container capacity Show An acquisition means for acquiring information; Tori According to the information obtained, To be printed The brightness value of the image Output brightness value equal to or greater than the brightness value determining means for determining a gamma table for correction; Decision and a correction means for correcting the luminance value of the image using the gamma table set in the When the capacity specified according to the acquired information is a first capacity, the determining means determines a first gamma table, and when the capacity specified according to the acquired information is a second capacity larger than the first capacity, the determining means determines a second gamma table in which an output luminance value for a certain input luminance value is larger than that of the first gamma table. It is characterized by: [Effects of the Invention]

[0008] According to the present disclosure, the capacity of the toner container is a first capacity, a first gamma table is determined, and when the capacity of the toner container is a second capacity greater than the first capacity, a second gamma table is determined in which an output luminance value for a certain input luminance value is greater than that of the first gamma table, and the luminance value of the image is corrected using the determined gamma table. It is possible. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. [Figure 2] FIG. 2 is a block diagram illustrating an example of the hardware configuration of the printing apparatus. [Figure 3]FIG. 2 is a block diagram illustrating an example of a control configuration of the printing system. [Figure 4] FIG. 10 is a diagram illustrating an example of the data configuration of a memory tag. [Figure 5] FIG. 10 is a diagram showing the relationship between cartridge types and gamma tables. [Figure 6] 10 is a flowchart showing the flow of gamma table switching processing. [Figure 7] 10 is a flowchart showing a processing flow when a print job is received. [Figure 8] FIG. 10 is a diagram illustrating an example of a gamma table. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiments do not limit the present disclosure, and not all of the combinations of features described in the embodiments are necessarily essential to solving the problems.

[0011] [Embodiment 1] <Configuration of a laser beam printer> The configuration of a laser beam printer, which is an example of a printing device according to this embodiment, will be described with reference to the drawings. Figure 1 is a cross-sectional view of the printing device.

[0012] The printer 200 has paper feed cassettes 511a-511d, an image forming unit 507, a main transport path 540, and a discharge transport path 541. The printer 200 also has multiple rollers, such as feed rollers 502a-502d, transport rollers 510a-510d, and 512a-512d, a registration roller 504, and a discharge roller 520, to transport the recording material (paper) along each transport path. The printer 200 also has multiple sensors for detecting the recording material within the device, such as paper presence sensors 501a-501d, a registration sensor 505, a paper detection sensor 506, and a discharge sensor 508. For simplicity's sake, the following descriptions omit the a, b, c, and d characters attached to the reference numerals of the paper feed cassettes 511a-511d and the components contained therein. When omitted, all paper feed cassettes or components are referred to.

[0013] A paper feed cassette 511 functions as a feeding means and supplies recording materials for forming images into the apparatus. The recording materials are recording media such as sheets, paper, and cardboard on which images are formed.

[0014] The image forming unit 507 includes an exposure unit (not shown), a toner container 513, a developing unit 514, and a photosensitive drum 515, which is an image carrier, in order to form an image on a recording material. The image forming unit 507 is configured by a cartridge in which the exposure unit, toner container 513, developing unit 514, and photosensitive drum 515 are integrally provided and these components are packed together. The image forming unit 507 forms an electrostatic latent image on the photosensitive drum (image carrier) 515 by exposure using the exposure unit. This electrostatic latent image is formed according to image data received by a controller 210, which will be described later. The formed electrostatic latent image is developed by the developing unit 514 using toner (developer) supplied from the toner container 513, and is transferred to the recording material at a predetermined transfer position. The toner image formed on the recording material is fixed to the recording material by applying heat and pressure using a fixing device (not shown). In addition, a cartridge that integrates consumables such as an exposure device, a toner container 513, a developing device 514, and a photosensitive drum 515 has the advantage of being easy to handle and that the replacement work does not require a service technician and can be done by the user himself.

[0015] The main transport path 540 is disposed between the feed roller 502 and the discharge roller 520, and is a transport path for forming an image on a recording material. The transport roller 510 exists as part of the paper feed cassette 511. Therefore, when the paper feed cassette 511 is pulled out, the paper transport path from the lower paper feed cassette 511 is cut off, and the recording material cannot be supplied to the printer, resulting in printing failure. The discharge transport path 541 is disposed between the discharge roller 520 and the outside of the printer 200, and is a transport path for discharging the recording material outside the printer.

[0016] The feed rollers 502 transport the recording materials placed in the paper feed cassettes 511 into the apparatus one by one. The transport rollers 510 are rollers that lift the recording materials fed from each paper feed cassette 511 up to the printer. The registration rollers 504 are rollers that adjust the timing at which an image is transferred to the transported recording materials in the image forming unit 507. The discharge rollers 520 are rollers that discharge the recording materials out of the apparatus.

[0017] The paper presence sensor 501 detects the presence or absence of a recording material in the paper feed cassette 511. The registration sensor 505, paper detection sensor 506, and discharge sensor 508 detect the conveyed recording material. These sensors may be mechanical switches or optical sensors. The registration sensor 505 is used to adjust the transfer timing between the conveyed recording material and the toner image formed on the photosensitive drum 515. The registration sensor 505 is also used to measure the length of the recording material in the sub-scanning direction. The length of the recording material in the sub-scanning direction is calculated from the time the registration sensor 505 detects the conveyed recording material and the conveyance speed of the recording material. The paper detection sensor 506 is used to detect the presence or absence of a recording material at both ends of the main conveyance path 540 and to calculate the length of the recording material in the main scanning direction from the results. In this embodiment, the printer 200 does not have a density sensor or a mechanism for reading the density of patches formed on the ITB belt.

[0018] <Printer control system> The printer control system will be explained with reference to the diagram. Figure 2 is a block diagram showing an example of the hardware configuration of the control system of a printing device. Here, the explanation will be given using the laser beam printer shown in Figure 1 as an example.

[0019] 2, the printer 200 has a controller 210, a print mechanism unit 220, an operation panel 221, an HDD (hard disk) 222, and a network communication module 223. The printer 200 is mountable (insertable) with a cartridge 224 provided with a memory tag 225. The controller 210 has a CPU 201, RAM 202, ROM 203, EEPROM 204, a print unit I / F 205, a panel I / F 206, an MC (memory controller) 207, and an NTC (network controller) 208. These components are connected by a system bus 209.

[0020] The CPU 201 is a printer CPU and performs overall control of access to various devices connected to the system bus 209 based on a control program stored in the program ROM of the ROM 203. Furthermore, the CPU 201 outputs image signals as output information to the print mechanism unit 220 connected via a print unit I / F (interface) 205. The print mechanism unit 220 can access a memory tag 225 provided in the cartridge 224. Therefore, the memory tag 225 can also be accessed by the controller 210 via the print mechanism unit 220. Therefore, the printer 200 can obtain information for identifying the cartridge by accessing the memory tag 225. The print mechanism unit 220 also includes a remaining toner amount detection sensor for detecting the remaining amount of toner in the cartridge 224. The print mechanism unit 220 calculates the remaining amount of toner using the remaining amount value read by the remaining amount detection sensor and the dot count of the printed image.

[0021] The program ROM of the ROM (Read Only Memory) 203 stores a control program for the CPU 201 and the like for executing the processes shown in the flowcharts of FIGS.

[0022] RAM (Random Access Memory) 202 is a storage medium that functions as the main memory, work area, etc. of CPU 201, and is configured so that the memory capacity can be expanded by an optional RAM connected to an expansion port (not shown). RAM 202 is used as a drawing memory for storing image data received from the host computer, a storage area for video signal ON / OFF information, other work areas, etc. EEPROM (Electrically Erasable Programmable Read-Only Memory) 204 is a non-volatile memory device that stores setting values ​​for various functions set on operation panel 221. EEPROM 204 is not limited to non-volatile memory, and may be configured as a non-volatile memory such as Flash ROM or eMMC (embedded Multi Media Card).

[0023] The operation panel 221 is equipped with operation switches, LED indicators, etc., and can be controlled from the CPU 201 via the panel I / F 206. The MC 207 controls access to the HDD 222, which stores print data received from the host computer, etc. The NTC 208 controls the network communication module 223, and can communicate with various host computers and devices on the network.

[0024] <Printing system control configuration> Next, the control configuration of a printing system including printer 200 will be described with reference to the drawings. Fig. 3 is a block diagram showing an example of the control configuration of the printing system. Fig. 3 shows an example of the processing configuration for managing cartridges in CPU 201 of printer 200. In Fig. 3, management server 100 is a host computer that functions as a management server for printing devices, and receives and manages information about cartridges 224 installed in each user's printing device via network 1000 such as the Internet.

[0025] Printer 200 has, broadly speaking, a controller 210, an operation panel 221, a printing mechanism 220, and a cartridge 224. In this embodiment, printer 200 is specifically assumed to be a laser beam printer (hereinafter referred to as LBP). Note that printers to which the present disclosure can be applied are not limited to LBPs, and may also be printers of other printing methods, such as inkjet printers and thermal (thermal transfer) printers.

[0026] In the printer 200, the controller 210 has an I / F (interface) unit 301 for connecting to the management server 100. The controller 210 further has a receive buffer 302 for temporarily storing and managing received data, etc., and a send buffer 303 for temporarily storing and managing send data, etc. The controller 210 also has a command analysis unit 306 that is responsible for analyzing print data, a print control unit 307, an image control unit 304, a gamma correction execution unit 312, an output control unit 309, a status management unit 308, a cartridge management unit 310, etc.

[0027] The I / F unit 301 transmits and receives print data to and from the management server 100. The print data received through the I / F unit 301 is sequentially stored in a receive buffer 302 that temporarily stores the data, and is read and processed as necessary by a command analysis unit 306 or an image control unit 304. The command analysis unit 306 is configured with a control program that conforms to each print control command system and print job control language. If the command analyzed by the command analysis unit 306 relates to image data such as bitmap data, the image control unit 304 is given an instruction to process the command. If the command relates to image data corresponding to the currently inserted cartridge 224, the gamma correction execution unit 312 is given an instruction to execute gamma correction processing. If the command relates to a command other than drawing, such as a paper feed selection command or a reset command, the print control unit 307 is given an instruction to process the command.

[0028] The image control unit 304 removes the command portion from the transferred image data command data, and if the image data is compressed, the image control unit 304 performs decompression processing and sends it to the gamma correction execution unit 312. The gamma correction execution unit 312 references a gamma table corresponding to the inserted cartridge and performs gamma correction processing on the image data (RGB signal), and the gamma-corrected image data is stored in the image buffer 305. The image buffer 305 may be managed by banding control, i.e., by the race between this image data reception processing and the output of the video signal to the print mechanism unit (printer engine) 220. Alternatively, if there is sufficient memory, an area capable of storing one page may be reserved as the image buffer 305.

[0029] The status management unit 308 has a function of determining various printer statuses based on information from the print control unit 307 and displaying the printer status on the operation panel 221. The status management unit 308 also has a function of returning the printer status in response to a status information acquisition command issued from the management server 100. The cartridge management unit 310 has a function of accessing the memory tag 225 of the cartridge 224 via the print mechanism unit 220 and detecting the toner life. The cartridge management unit 310 also has a function of determining whether the cartridge 224 is a genuine product or a recycled product.

[0030] The output control unit 309 converts the image bitmap data, which is the gamma-corrected image data stored in the image buffer 305, into a CMYK signal and transfers it as a video signal to the print mechanism unit (printer engine) 220. The print mechanism unit 220 is a mechanism for forming a permanent visible image on a recording medium from the received video signal.

[0031] <Memory tag data> An example of the structure of data stored in the memory tag will be described with reference to the accompanying drawings. FIG. 4 shows an example of the structure of data stored in the memory tag 225. Multiple pieces of information, such as information for identifying (specifying) the cartridge at the time of factory shipment or before it reaches the user, are written to the memory tag 225. The memory tag data 400 includes multiple pieces of information, such as information 401-403. Information 401 is information indicating a unique ID that is unique among multiple cartridges and indicates the serial number assigned to each cartridge. Information 402 is information indicating the manufacturing date of the cartridge. Information 403 is information indicating the toner capacity. In this embodiment, the capacity information indicates the number of pages that can be printed on A4 paper with a 3% print rate. In other words, the capacity information 403 indicates the number of pages that can be printed from a new cartridge with the memory tag attached, and does not indicate a value that changes with each printing operation. The printer 200 reads the capacity information 403 from the memory tag and identifies the type of cartridge currently inserted. The capacity information in this embodiment is an example, and the format is not limited to this as long as it is information that can identify the cartridge capacity type, such as information about the weight of the toner capacity of the cartridge at the time of shipment, an ID indicating the cartridge capacity type, etc. Information 401-403 is part of the information written in memory tag 225, and information other than this information is also written in memory tag 225.

[0032] <Relationship between cartridge type and gamma table> The relationship between cartridge types and gamma tables will be explained using the drawings. Fig. 5 is a diagram showing the relationship between three types of cartridges and gamma tables. In this embodiment, the types of cartridges 224 used in printer 200 correspond to one of three types: small capacity, medium capacity, and large capacity, depending on the size (capacity) of the toner container 513 of the cartridge 224. The table shown in Fig. 5 is stored in ROM 203.

[0033] The gamma correction table list 550 defines, for each cartridge type (CRG type) 551, a corresponding capacity 552 and a gamma table 553 in association with each other.

[0034] The cartridge type 551 indicates the capacity type of the toner container that the cartridge has, and is classified into "small capacity," "medium capacity," "large capacity," and "unknown" (capacity unknown).

[0035] Capacity 552 indicates the capacity of each cartridge, and corresponds to the capacity indicated by capacity information 403 stored in memory tag 225 provided in each cartridge. As described above, capacity information 403 indicates the number of pages that can be printed for content with a print rate of 3% on A4 paper size. If the cartridge type is "small capacity," capacity information 403 indicates that 10K = 10,000 pages of the content can be printed from a new cartridge.

[0036] The gamma table 553 represents four types of gamma tables corresponding to each cartridge type. The first to third tables (first to third gamma tables) are lookup tables (LUTs) for converting input / output values ​​according to the input / output characteristics of each cartridge. The fourth table (fourth gamma table) is a lookup table (LUT) for converting input / output values ​​when the volume information is not read correctly and the cartridge type is unknown.

[0037] The "small capacity" in the cartridge type 551 corresponds to a cartridge 224 having a small size (capacity) of the toner container 513. The "small capacity" is associated with the "10.0K" in the capacity 552 and the "first table" (first gamma table) in the gamma table 553. Therefore, when a "small capacity" cartridge is inserted and it is determined that the cartridge type is small capacity based on the capacity information read from the memory tag provided on the cartridge, gamma correction processing is performed by referring to the first table.

[0038] The "medium capacity" in the cartridge type 551 corresponds to a toner container 513 of a medium size (capacity) that the cartridge 224 has. The "medium capacity" is linked to the "25.0K" in the capacity 552 and the "second table" (second gamma table) in the gamma table 553. Therefore, when a "medium capacity" cartridge is inserted and it is determined that the cartridge type is medium capacity based on the capacity information read from the memory tag provided on the cartridge, gamma correction processing is performed by referring to the second table.

[0039] The "large capacity" of the cartridge type 551 corresponds to a large size (capacity) of the toner container 513 of the cartridge 224. The "large capacity" is linked to the "40.0K" of the capacity 552 and the "third table" (third gamma table) of the gamma table 553. Therefore, when a "large capacity" cartridge is inserted and it is determined that the cartridge type is large capacity based on the capacity information read from the memory tag provided on the cartridge, gamma correction processing is performed by referring to the third table.

[0040] "Unknown" in cartridge type 551 (toner container capacity unknown) corresponds to a case where capacity information cannot be read correctly for some reason, such as a malfunction of memory tag 225. "Unknown" is linked to "-" in capacity 552 and "fourth table" (fourth gamma table) in gamma table 553. Therefore, when any cartridge is inserted and capacity information cannot be read correctly from the memory tag provided on the cartridge, and it is determined that the cartridge type is unknown, gamma correction processing is performed by referring to the fourth table.

[0041] The selection flow of the gamma table for each cartridge will be described later.

[0042] <Gamma table switching process> Next, a method for switching the gamma table depending on the type of cartridge inserted (installed) in the printer will be described with reference to the drawings. FIG. 6 is a flowchart showing the flow of the process for switching (selecting) the gamma table. This process is implemented by the CPU 201 reading a control program stored in the ROM 203 into the RAM 202 and executing it. Some or all of the functions of the steps in FIG. 6 may be implemented by hardware such as an ASIC or electronic circuit. The symbol "S" in the description of each process indicates a step in the flowchart, and this also applies to subsequent flowcharts.

[0043] In S601, the printer 200 determines whether it is startup, door opening / closing, or waking up from sleep. The determination of whether it is startup is made, for example, based on the results of checking the current status information of the printer 200. The determination of whether it is door opening / closing is made, for example, based on the detection results of a door sensor that detects door opening / closing. The determination of whether it is waking up from sleep is made, for example, based on the results of checking the current status information of the printer 200. If it is determined that it is not startup, door opening / closing, or waking up from sleep (NO in S601), the printer 200 executes the process of S601 again. If it is determined that it is startup, door opening / closing, or waking up from sleep (YES in S601), the process proceeds to S602. That is, the printer 200 continues to wait until it is in one of the following states: startup, door opening / closing, or waking up from sleep. If it is in one of the following states, the process proceeds to S602.

[0044] In S602, the printer 200 accesses the memory tag 225 provided on the inserted cartridge 224 and reads the capacity information 403 from the memory tag 225. If the capacity information cannot be read even after a predetermined time has elapsed since the start of the reading process, the reading process is performed again. If the capacity information cannot be read even after the reading process has been performed a predetermined number of times, information indicating that the reading was not performed normally is obtained, and after obtaining the information, the process proceeds to S603.

[0045] In S603, the printer 200 checks the result of reading the capacity information 403 and determines whether the reading was successful. If the result of the determination that the reading was successful is obtained (YES in S603), the process proceeds to S604.

[0046] In S604, the printer 200 determines whether the value of the read capacity information 403 is greater than 30K, which is the first threshold. If the determination result is that the value of the read capacity information 403 is greater than 30K (YES in S604), the process proceeds to S610. In S610, the printer 200 determines the cartridge type to be large capacity. Accordingly, in S611 following the process of S610, the printer 200 determines to select the third table (third gamma table) as the gamma table to be referenced during gamma correction.

[0047] On the other hand, if the determination result indicates that the value of the read capacity information 403 is 30K or less (NO in S604), the process proceeds to S605.

[0048] In S605, the printer 200 determines whether the value of the read capacity information 403 is greater than 20K, which is the second threshold. If the determination result is that the value of the read capacity information 403 is greater than 20K (YES in S605), the process proceeds to S608. In S608, the printer 200 determines the cartridge type to be medium capacity. Accordingly, in S609 following the process of S608, the printer 200 determines to select the second table (second gamma table) as the gamma table to be referenced during gamma correction.

[0049] On the other hand, if the read capacity information 403 is determined to be 20K or less (NO in S605), the process proceeds to S606.

[0050] In S606, the printer 200 determines the cartridge type to be small capacity. Accordingly, in S607 following the processing of S606, the printer 200 determines to select the first table (first gamma table) as the gamma table to be referenced during gamma correction.

[0051] On the other hand, if the determination result is that the memory tag 225 was not read normally due to some cause such as a memory tag malfunction when reading the capacity information of the memory tag 225 (NO in S603), the process proceeds to S612.

[0052] In S612, the printer 200 determines that the cartridge capacity type is unknown. In S613 following the processing of S612, the printer 200 determines to select the fourth table (fourth gamma table) as the gamma table to be referenced during gamma correction.

[0053] That is, the cartridge type (volume of the toner container) is identified according to the acquired information, and a gamma table for correcting the luminance value of the image to be printed corresponding to the identified result is determined.

[0054] Then, after a gamma table corresponding to the cartridge type is selected in any of the above-described processes of S607, S609, S611, and S613, the process proceeds to S614.

[0055] In S614, the printer 200 stores in the RAM 202 the gamma table type selected in any one of the processes of S607, S609, S611, and S613.

[0056] In this embodiment, the cartridge capacity determination (S604, S605) is compared with a certain threshold value using an inequality sign, but it may also be compared with a value that each piece of capacity information can take using an equality sign.

[0057] <Processing when a print job is received> The flow of processing when a print job is received will be explained using the diagram. Fig. 7 is a flowchart showing the flow of processing when the printer 200 receives a print job. Note that this processing is realized by the CPU 201 reading a control program stored in the ROM 203 into the RAM 202 and executing it.

[0058] In S701, the printer 200 determines whether or not it has received a print job submitted from the management server 100, which is the host computer. If it is determined that a print job has not been received (NO in S701), the process of S701 is executed again. On the other hand, if it is determined that a print job has been received (YES in S701), the process proceeds to S702. That is, the printer 200 continues to wait for a print job to be submitted from the management server 100, and if it has received a print job, the process proceeds to S702.

[0059] In S702, the printer 200 reads out from the RAM 202 the gamma table type that was saved in the RAM 202 in the processing of S614 described above.

[0060] In S703, the gamma correction execution unit 312 references the gamma table corresponding to (associated with) the gamma table type read in S702 and performs gamma correction on the received image data. That is, the gamma table is used to correct the brightness value of the image to be printed, thereby adjusting the color of the image. In S704, the printer 200 performs printing on the conveyed recording medium based on the gamma-corrected image data. That is, the printer 200 forms an image on the recording medium based on the video signal that is output by converting the gamma-corrected image data (RGB signal) into CMYK signals.

[0061] In S705, printer 200 determines whether printing of all pages of the received print job has been completed. If the determination result indicates that printing of all pages has not been completed (NO in S705), the process proceeds to S703, and the processes from S703 onward are performed on the image data of unprocessed pages. On the other hand, if the determination result indicates that printing of all pages has been completed (YES in S705), the flow shown in Fig. 7 ends. That is, printer 200 checks whether printing of all pages of the received print job has been completed, and if printing of all pages of the received print job has been completed, the process ends.

[0062] <Gamma table> 8 is a diagram showing an example of a gamma table to be referenced in this embodiment. The gamma table is a lookup table for converting the luminance values ​​of an RGB image to be corrected.

[0063] A first table 801, a second table 802, a third table 803, and a fourth table 804 show conversion curves, and correspond to the first table, the second table, the third table, and the fourth table in Figure 5, respectively. The horizontal axis of the table shows the input luminance value (0 to 255) to be corrected, and the vertical axis shows the output luminance value (0 to 255) corresponding to each input value after conversion (correction). When gamma correction is performed, each pixel of the image to be corrected is converted to a luminance value on the gamma table.

[0064] In this embodiment, the larger the toner capacity and the longer the cartridge life, the thicker the film thickness of the photosensitive drum included. The thicker the photosensitive drum film thickness, the smaller the potential attenuation for the same amount of light, so the diameter of one dot adhering to the photosensitive drum becomes, resulting in a lower density of halftones. In other words, the brightness value becomes smaller than the ideal value. The gamma table shown in Figure 8 is a table that converts halftone inputs into higher brightness values. Due to the above-mentioned background, the thicker the photosensitive drum film thickness included with the cartridge, the higher the conversion to brightness values ​​becomes.

[0065] As described above, according to this embodiment, the capacity of the inserted cartridge is determined upon startup, door opening / closing, and sleep recovery, and gamma correction is performed by referencing the gamma table corresponding to that capacity. Therefore, gamma correction can be performed using the optimal gamma table for each cartridge. For example, even if the printer 200 does not have a detection sensor or scanner for detecting the density of toner applied to the transfer belt, the following effects can be achieved. That is, by correcting the brightness value of the image to be printed using the gamma table associated with the cartridge type of the currently inserted cartridge, the color of the image can be appropriately adjusted.

[0066] [Other embodiments] In the above example, a cartridge in which an exposure unit, a toner container, a developing unit, and a photosensitive drum are integrated is used as a replaceable part. The present disclosure may also be applied to an image forming apparatus in which the exposure unit, the toner container, the developing unit, and the photosensitive drum are each replaceable.

[0067] The present disclosure can also be realized by a process in which a program that realizes one or more functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device read and execute the program. The present disclosure can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

Claims

1. An image forming apparatus, an acquisition unit that acquires information indicating the capacity of a toner container provided in the image forming apparatus; a determining means for determining a gamma table for correcting the luminance value of the image to be printed to an output luminance value equal to or greater than the luminance value according to the acquired information; a correction means for correcting the luminance value of the image using the determined gamma table, An image forming apparatus characterized in that when the capacity specified in accordance with the acquired information is a first capacity, the determination means determines a first gamma table, and when the capacity specified in accordance with the acquired information is a second capacity larger than the first capacity, the determination means determines a second gamma table in which the output luminance value for a certain luminance value is larger than that of the first gamma table.

2. a cartridge in which the toner container and an image carrier that carries the toner contained in the toner container are integrally provided can be mounted; the cartridge includes a memory that stores the information indicating the capacity of the toner container; 2. The image forming apparatus according to claim 1, wherein the acquiring unit acquires the information indicating the capacity of the toner container by reading it from the memory provided in the cartridge.

3. The toner container is available in a plurality of types depending on the capacity of the toner container, the gamma table is of a plurality of types corresponding to the respective capacities of the toner container; 3. The image forming apparatus according to claim 1, wherein the determining unit determines the capacity of the toner container according to the acquired information, and determines the gamma table corresponding to the determination result.

4. The gamma table is associated with an unknown capacity of the toner container, When the acquisition means cannot acquire the information, 4. The image forming apparatus according to claim 1, wherein the determining unit determines the gamma table associated with the unknown capacity of the toner container.

5. 5. The image forming apparatus according to claim 1, further comprising a forming unit that forms an image on a recording medium based on the image whose luminance value has been corrected.

6. A control method for an image forming apparatus, comprising: an acquiring step of acquiring information indicating a capacity of a toner container provided in the image forming apparatus; a determining step of determining a gamma table for correcting the luminance value of the image to be printed to an output luminance value equal to or greater than the luminance value according to the acquired information; a correction step of correcting the luminance value of the image using the determined gamma table, A control method for an image forming apparatus, characterized in that, when the capacity specified according to the acquired information is a first capacity, the determination step determines a first gamma table, and when the capacity specified according to the acquired information is a second capacity larger than the first capacity, the determination step determines a second gamma table in which the output luminance value for a certain luminance value is larger than that of the first gamma table.

7. A program for causing a computer to execute each of the means of the image forming apparatus according to any one of claims 1 to 5.

Images