Image forming apparatus, setting method, and setting program

Abstract

To reduce the risk associated with image adjustment when a person without technical knowledge of an image forming apparatus performs image adjustment.SOLUTION: An image forming apparatus 100 has a plurality of user authority modes. The image forming apparatus 100 comprises a setting unit that sets an adjustment range in which a user can make an adjustment for an image adjustment parameter according to a currently designated target user authority mode, of the plurality of user authority modes. The plurality of user authority modes include a first user authority mode and a second user authority mode. The first user authority mode and the second user authority mode have different adjustment ranges.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an image forming apparatus, a setting method and a setting program for setting an adjustment range in which a user can adjust an image adjustment parameter of the image forming apparatus. [Background technology]

[0002] Adjusting the image of an image forming device is a task that requires careful attention because excessive changes to certain image adjustment parameters can result in risks associated with image adjustment, such as a decline in image quality. For this reason, the image adjustment function of an image forming device has traditionally only been available to those with technical knowledge of image forming devices, such as service personnel. However, users have diverse preferences (requirements) for image quality. The image quality that image forming device manufacturers aim for does not necessarily satisfy users. For this reason, there is a demand for users to be able to make image adjustments.

[0003] Recently, the number of parts in image forming apparatuses that have been converted into CRUs (Customer Replaceable Units) is increasing. In general, image adjustment is required after replacing parts. Therefore, there is a demand for the user to be able to adjust the image.

[0004] Thus, there is a need for an image forming apparatus that allows a user to adjust an image. For example, Japanese Patent Application Laid-Open No. 2020-67557 (Patent Document 1) discloses an image forming apparatus that allows a user to adjust an image.

[0005] The image forming apparatus disclosed in Patent Document 1, when receiving an adjustment amount of a first printing parameter, presents to a user an adjustment amount recommended for a second printing parameter based on the adjustment amount of the first printing parameter. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-67557 A Summary of the Invention [Problem to be solved by the invention]

[0007] The image forming apparatus disclosed in Patent Document 1 presents the user with recommended adjustment amounts for the second print parameters, but does not present recommended adjustment amounts for the first print parameters, which may result in risks associated with image adjustment.

[0008] An object of the present disclosure is to reduce risks associated with image adjustment when image adjustment is performed by a person without technical knowledge of image forming apparatuses. [Means for solving the problem]

[0009] An image forming apparatus according to an aspect of the present disclosure has a plurality of user authority modes. The image forming apparatus includes a setting unit that sets an adjustment range that a user can adjust for an image adjustment parameter according to a currently designated target user authority mode among the plurality of user authority modes. The plurality of user authority modes include a first user authority mode and a second user authority mode. The adjustment range differs between the first user authority mode and the second user authority mode.

[0010] Preferably, the width of the adjustment range in the second user authority mode is narrower than the width of the adjustment range in the first user authority mode.

[0011] Preferably, the adjustment range in the second user authority mode is included in the adjustment range in the first user authority mode.

[0012] Preferably, the image forming apparatus further includes a storage unit that stores usage history information of the image forming apparatus. When the target user authority mode is one or more predetermined user authority modes among the plurality of user authority modes, the setting unit sets the adjustment range based on the usage history information.

[0013] Preferably, the image forming apparatus forms an image on a sheet using toner, and the image adjustment parameters include a maximum amount of toner adhesion.

[0014] Preferably, the usage history information includes information on print coverage.

[0015] Preferably, the one or more predetermined user authority modes include a second user authority mode. When the print coverage exceeds a threshold, the setting unit sets an upper limit of the adjustment range of the maximum adhesion amount lower than when the print coverage is equal to or less than the threshold.

[0016] Preferably, the usage history information includes information on the number of printed copies.

[0017] Preferably, the one or more predetermined user authority modes include a second user authority mode. When the number of printed copies exceeds a threshold, the setting unit sets an upper limit of the adjustment range of the maximum adhesion amount lower than when the number of printed copies is equal to or less than the threshold.

[0018] Preferably, the plurality of user authority modes further includes a third user authority mode, wherein the width of the adjustment range in the second user authority mode is narrower than the width of the adjustment range in the third user authority mode, and the width of the adjustment range in the third user authority mode is narrower than the width of the adjustment range in the first user authority mode.

[0019] A setting method according to another aspect of the present disclosure is a method for setting an adjustment range that a user can adjust for an image adjustment parameter of an image forming apparatus having a plurality of user authority modes. The setting method includes setting an adjustment range according to a currently designated target user authority mode among the plurality of user authority modes. The plurality of user authority modes include a first user authority mode and a second user authority mode. The adjustment range differs between the first user authority mode and the second user authority mode.

[0020] A setting program according to another aspect of the present disclosure causes one or more computers to execute the setting method. Effect of the Invention

[0021] According to the present disclosure, when a person without technical knowledge of image forming apparatuses performs image adjustment, risks associated with the image adjustment are reduced. [Brief description of the drawings]

[0022] [Figure 1] 1 is a diagram illustrating an example of an internal configuration of an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a control configuration of the image forming apparatus 100. [Diagram 3] 1A to 1C are diagrams illustrating an overview of an image density adjustment process of the image forming apparatus 100. [Figure 4] 13 is a diagram showing an example of a screen for specifying the maximum density of an image in image forming apparatus 100. FIG. [Diagram 5] FIG. 13 is a diagram showing an example of a first LUT 623a. [Figure 6] FIG. 13 is a diagram showing an example of a second LUT 623b. [Figure 7] FIG. 2 is a plan view showing a schematic diagram of a test patch arranged on the intermediate transfer belt 25. [Figure 8] FIG. 2 is a side view showing a schematic diagram of a test patch disposed on the intermediate transfer belt 25. [Figure 9] 11 is a graph showing an example of the relationship between the output voltage of a detector SE and the amount of toner attached to the surface of an intermediate transfer belt 25. [Figure 10] 4 is a graph showing an example of the relationship between the developing bias and the amount of toner attached to the surface of the intermediate transfer belt 25. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, with reference to the drawings, an embodiment and a modified example according to the present disclosure will be described. In the following description, the same parts and components are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. Note that the embodiment and modified examples described below may be combined as appropriate.

[0024] In the following description, the x-axis, y-axis, and z-axis are perpendicular to one another. In the following description, the negative direction of the z-axis is also referred to as the "lower side," and the positive direction of the z-axis is also referred to as the upper side.

[0025] In the following description, the user may be a person who has technical knowledge of the image forming device, or may be a person who does not have technical knowledge of the image forming device. A person who has technical knowledge of the image forming device includes, for example, a service person (maintenance worker). A person who does not have technical knowledge of the image forming device includes, for example, at least one of a general user, an administrator who manages the machine, a worker who installs the machine, and a transport company that transports the machine.

[0026] In the following description, the "maximum density of an image" may be simply referred to as the "maximum density," and the "maximum amount of toner adhesion" may be simply referred to as the "maximum amount of adhesion."

[0027] <a 画像形成装置の構成> The configuration of an image forming apparatus according to the present embodiment will be described with reference to FIGS.

[0028] FIG. 1 is a diagram showing an example of an internal configuration of an image forming apparatus according to the present embodiment. Referring to FIG. 1, the image forming apparatus 100 according to the present embodiment is a tandem-type color printer. The image forming apparatus 100 forms a full-color image or a monochrome image on a recording sheet S by a well-known electrophotographic method based on image data. That is, the image forming apparatus 100 forms an image on the recording sheet S using toner. The image data is input from an external device via a network NW. Alternatively, the image data may be image data of an original read by an image reading unit 4. The network NW is, for example, a LAN (Local area network). The recording sheet S may be a recording paper or an OHP (Overhead projector) sheet.

[0029] Image forming apparatus 100 includes a printer engine 111, an engine control unit 112, an image reading unit 4, an operation panel 5, an image control board 6, and a printer controller 7. The printer engine 111 includes an image forming unit 1, a paper feeding unit 2, and a fixing unit 3. The engine control unit 112 controls the printer engine 111.

[0030] The printer engine 111 will now be described. The paper feed unit 2 is disposed below the image forming unit 1. The paper feed unit 2 includes a paper feed cassette 22 that accommodates recording sheets S. The recording sheets S in the paper feed cassette 22 are supplied to the image forming unit 1.

[0031] The image forming unit 1 forms a toner image using toners of the respective colors of yellow (Y), magenta (M), cyan (C), and black (K). The image forming unit 1 transfers the toner image onto a recording sheet S supplied from a paper feed unit 2. The image forming unit 1 includes process units 10Y, 10M, 10C, and 10K, an exposure unit 28, an intermediate transfer belt 25, rollers 23 and 24, primary transfer rollers 27Y, 27M, 27C, and 27K, a secondary transfer roller 26, toner cartridges 17Y, 17M, 17C, and 17K, toner supply mechanisms 19Y, 19M, 19C, and 19K, and a detector SE.

[0032] An intermediate transfer belt 25 is disposed along the x-axis direction at approximately the center in the z-axis direction of the image forming apparatus 100. The intermediate transfer belt 25 is wound around rollers 23 and 24, and is configured to be rotated by a motor (not shown).

[0033] Process units 10Y, 10M, 10C, and 10K are provided below intermediate transfer belt 25 so as to be detachable from image forming section 1. Process units 10Y, 10M, 10C, and 10K are arranged in this order along a portion of intermediate transfer belt 25 that moves in the positive direction of the x-axis (the direction of arrow A1). Process unit 10Y forms a yellow toner image. Process unit 10M forms a magenta toner image. Process unit 10C forms a cyan toner image. Process unit 10K forms a black toner image. Each of process units 10Y, 10M, 10C, and 10K includes a plurality of process means that form toner images of the corresponding color.

[0034] Each of the process units 10Y, 10M, 10C, and 10K is configured to be removed from the image forming unit 1 by being pulled out toward the front side (negative direction of the y-axis) of the image forming unit 1. Also, each of the process units 10Y, 10M, 10C, and 10K is attached to the image forming unit 1 by being inserted toward the rear side of the image forming unit 1 (positive direction of the y-axis).

[0035] Toner cartridges 17Y, 17M, 17C, and 17K are disposed above process units 10Y, 10M, 10C, and 10K, with intermediate transfer belt 25 in between. Toner cartridge 17Y contains yellow toner. Toner cartridge 17M contains magenta toner. Toner cartridge 17C contains cyan toner. Toner cartridge 17K contains black toner.

[0036] Between the intermediate transfer belt 25 and the toner cartridges 17Y, 17M, 17C, and 17K, toner supply mechanisms 19Y, 19M, 19C, and 19K are disposed, respectively. The toner contained in the toner cartridges 17Y, 17M, 17C, and 17K is supplied to the process units 10Y, 10M, 10C, and 10K by the toner supply mechanisms 19Y, 19M, 19C, and 19K, respectively. The process units 10Y, 10M, 10C, and 10K have substantially the same configuration, except that the colors of the toner supplied from the toner cartridges 17Y, 17M, 17C, and 17K are different from each other.

[0037] The process units 10Y, 10M, 10C, and 10K include photoconductor drums 11Y, 11M, 11C, and 11K, respectively. The photoconductor drums 11Y, 11M, 11C, and 11K are rotatably arranged below the intermediate transfer belt 25 and facing the intermediate transfer belt 25. A photoconductor layer is provided over the entire circumference of each of the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11K. Each of the photoconductor drums 11Y, 11M, 11C, and 11K is configured to rotate in the direction indicated by the arrow A2 around a rotation axis along the y-axis direction. The direction indicated by the arrow A2 is a clockwise direction when the photoconductor drums 11Y, 11M, 11C, and 11K are viewed in plan from the positive direction of the z-axis direction.

[0038] The process units 10Y, 10M, 10C, and 10K include cleaning blades 16Y, 16M, 16C, and 16K, respectively. The cleaning blades 16Y, 16M, 16C, and 16K are disposed on the side of the photoconductor drums 11Y, 11M, 11C, and 11K that is separated from the intermediate transfer belt 25 in the rotation direction (the downstream side of the rotation direction of the photoconductor drums 11Y, 11M, 11C, and 11K). The cleaning blades 16Y, 16M, 16C, and 16K are configured to scrape off toner remaining on the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11K.

[0039] The process units 10Y, 10M, 10C, and 10K include chargers 12Y, 12M, 12C, and 12K, respectively. The chargers 12Y, 12M, 12C, and 12K are disposed downstream of the cleaning blades 16Y, 16M, 16C, and 16K in the direction of rotation of the photoconductor drums 11Y, 11M, 11C, and 11K, respectively. The chargers 12Y, 12M, 12C, and 12K are configured to uniformly charge the photosensitive layers of the photoconductor drums 11Y, 11M, 11C, and 11K to a predetermined charging potential.

[0040] An exposure device 28 is disposed below the process units 10Y, 10M, 10C, and 10K. Laser beams LY, LM, LC, and LK are irradiated from the exposure device 28 onto the photoconductor drums 11Y, 11M, 11C, and 11K, respectively.

[0041] The exposure device 28 includes four laser diodes corresponding to the process units 10Y, 10M, 10C, and 10K, respectively. The four laser diodes emit laser beams LY, LM, LC, and LK, respectively. The laser beams LY, LM, LC, and LK are irradiated onto the photosensitive layers of the photoconductor drums 11Y, 11M, 11C, and 11K via polygon mirrors and scanning lenses, etc. As a result, electrostatic latent images are formed on the photosensitive layers of the photoconductor drums 11Y, 11M, 11C, and 11K, which are uniformly charged by the chargers 12Y, 12M, 12C, and 12K, respectively.

[0042] The process units 10Y, 10M, 10C, and 10K include developing devices 14Y, 14M, 14C, and 14K, respectively. The developing devices 14Y, 14M, 14C, and 14K are disposed downstream in the rotation direction of the photoconductor drums 11Y, 11M, 11C, and 11K from the exposure positions (irradiation positions) of the photoconductor drums 11Y, 11M, 11C, and 11K irradiated with the laser beams LY, LM, LC, and LK, respectively. The developing devices 14Y, 14M, 14C, and 14K develop the electrostatic latent images formed on the photosensitive layers of the photoconductor drums 11Y, 11M, 11C, and 11K, respectively, with a two-component developer. The two-component developer used by the developing device 14Y includes a yellow toner and a carrier having magnetic properties. The two-component developer used by the developing device 14M includes a magenta toner and a carrier having magnetic properties. The two-component developer used by the developing unit 14C contains cyan toner and a magnetic carrier, whereas the two-component developer used by the developing unit 14K contains black toner and a magnetic carrier.

[0043] In this manner, the photoconductor drums 11Y, 11M, 11C, and 11K, the chargers 12Y, 12M, 12C, and 12K, and the developing units 14Y, 14M, 14C, and 14K constitute a process means for forming a toner image.

[0044] Primary transfer rollers 27Y, 27M, 27C, and 27K are disposed above the process units 10Y, 10M, 10C, and 10K, facing the photoconductor drums 11Y, 11M, 11C, and 11K, respectively, via the intermediate transfer belt 25. The primary transfer rollers 27Y, 27M, 27C, and 27K are attached to the image forming unit 1. By applying a transfer bias voltage to the primary transfer rollers 27Y, 27M, 27C, and 27K, an electric field is formed between the primary transfer rollers 27Y, 27M, 27C, and 27K and the photoconductor drums 11Y, 11M, 11C, and 11K facing them, respectively.

[0045] The toner images formed on the photosensitive drums 11Y, 11M, 11C, and 11K, respectively, are primarily transferred onto the intermediate transfer belt 25 by the action of electric fields formed between the primary transfer rollers 27Y, 27M, 27C, and 27K and the photosensitive drums 11Y, 11M, 11C, and 11K, respectively.

[0046] When a full-color image is formed, the operation timings of the image formation of the process units 10Y, 10M, 10C, and 10K are shifted so that the toner images formed on the photoconductor drums 11Y, 11M, 11C, and 11K are multiple-transferred to the same area on the intermediate transfer belt 25. In contrast, when a monochrome image is formed, a toner image is formed on the photoconductor drum of a selected process unit (for example, process unit 10K for black toner). The toner image is then transferred onto a predetermined area on the intermediate transfer belt 25 by a primary transfer roller disposed opposite the process unit.

[0047] After the toner images are transferred to the intermediate transfer belt 25, the toner remaining on the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11K is scraped off by cleaning blades 16Y, 16M, 16C, and 16K.

[0048] The intermediate transfer belt 25 transports the transferred toner image to a position where the roller 23 faces the secondary transfer roller 26. The secondary transfer roller 26 is disposed so as to face the roller 23 with the intermediate transfer belt 25 interposed therebetween.

[0049] The secondary transfer roller 26 is pressed against the intermediate transfer belt 25. A transfer nip is formed between the secondary transfer roller 26 and the intermediate transfer belt 25. A transfer bias voltage is applied to the secondary transfer roller 26. As a result, an electric field is formed between the secondary transfer roller 26 and the intermediate transfer belt 25. A recording sheet S sent from the paper feed cassette 22 to the sheet transport path 21 is transported to the transfer nip. The toner image transferred onto the intermediate transfer belt 25 is secondarily transferred to the recording sheet S transported in the sheet transport path 21 by the action of the electric field formed between the secondary transfer roller 26 and the intermediate transfer belt 25. The recording sheet S that has passed through the transfer nip is transported to the fixing unit 3 arranged above the secondary transfer roller 26.

[0050] The fixing unit 3 fixes the toner image onto the recording sheet S. The fixing unit 3 includes a heating roller 31 and a pressure roller 32 that are pressed against each other in the x-axis direction. A fixing nip is formed between the heating roller 31 and the pressure roller 32. A heater lamp 33 is disposed at the axial center of the heating roller 31. The heating roller 31 is configured to be heated by the heater lamp 33. In the fixing unit 3, an unfixed toner image on the recording sheet S is fixed onto the recording sheet S by heating from the heating roller 31 and pressing from the pressure roller 32 while passing through the fixing nip. The recording sheet S with the fixed toner image is discharged onto a paper discharge tray 35 by a paper discharge roller 34.

[0051] The image reading unit 4, the operation panel 5, the image control board 6, and the printer controller 7 will be described with reference to Fig. 2. The detector SE will be described with reference to Figs. 7 and 8.

[0052] Fig. 2 is a diagram showing a control configuration of image forming apparatus 100. Referring to Fig. 2, image forming apparatus 100 includes a main body unit 9 and a printer controller 7. Image forming apparatus 100 transmits and receives information to and from an external device 500 on a network via a LAN interface 74 of the printer controller 7.

[0053] The following describes the main body 9. The main body 9 includes an image reading unit 4, an operation panel 5, an image control board 6, and a printing unit 8.

[0054] The image reading unit 4 includes a scanner 41 and an image reading control unit 42. The scanner 41 includes an ADF (Auto Document Feeder) and an image sensor. The image reading control unit 42 controls the scanner 41 based on instructions from the control unit 610. The scanner 41 reads an original document and obtains an image of the original document. The image reading control unit 42 outputs an analog image signal indicating the image obtained by the scanner 41 to the reading processing unit 650.

[0055] The operation panel 5 includes a display unit 51, an operation unit 52, and an operation display control unit 53. The operation unit 52 includes at least one of a switch, a button, a numeric keypad, an operation key, and a touch panel. The operation display control unit 53 causes the display unit 51 to display various screens for inputting various setting conditions in accordance with a display signal input from the control unit 610. The operation display control unit 53 also causes the display unit 51 to display the results of various processes in accordance with a display signal input from the control unit 610. The operation display control unit 53 also outputs an operation signal input from the operation unit 52 to the control unit 610.

[0056] The image control board 6 includes a control unit 610, a non-volatile memory 620, a RAM (Random Access Memory) 630, a HDD (Hard Disc Drive) 640, a read processing unit 650, a DRAM (Dynamic Random Access Memory) control IC (Integrated Circuit) 660, an image memory 670, and a write processing unit 680.

[0057] Control unit 610 includes a CPU (Central Processing Unit) etc. Control unit 610 reads out a specified program from programs 621 stored in non-volatile memory 620, and loads and executes the program in RAM 630. By executing program 621, control unit 610 controls each unit of image forming apparatus 100 and realizes various processes according to the present embodiment.

[0058] The non-volatile memory 620 is an example of a "storage unit" in this disclosure. The non-volatile memory 620 stores a program 621. The program 621 includes a plurality of computer-readable instructions for controlling the image forming apparatus 100. The program 621 includes a system program and various application programs.

[0059] The various application programs include a service mode program and a normal mode program. The service mode program is a program for operating image forming apparatus 100 in the service mode. The normal mode program is a program for operating image forming apparatus 100 in the normal mode. Control unit 610 reads out the user authority mode program input from operation unit 52 and controls each unit of image forming apparatus 100.

[0060] The various application programs include a “setting program” in this disclosure. The setting program is a program for setting the adjustment range within which the user can adjust image adjustment parameters.

[0061] Program 621 may be provided not as a standalone program but as part of an arbitrary program. In this case, the processing according to the present embodiment is realized in cooperation with the arbitrary program. Even if the program does not include some of the modules, it does not deviate from the spirit of image forming apparatus 100 according to the present embodiment. In addition, some or all of the functions provided by program 621 may be realized by dedicated hardware.

[0062] The non-volatile memory 620 further stores various data, including association information 622, a look up table (LUT) 623, print coverage information 624, and information 625 on the number of copies to be printed.

[0063] The related information 622 is used for toner adhesion amount control. The related information 622 indicates the relationship between the output voltage of the detector SE and the amount of toner adhesion on the surface of the intermediate transfer belt 25. The toner adhesion amount control is a control for setting the development biases of the developers 14Y, 14M, 14C, and 14K to appropriate values ​​so that the amount of toner adhesion becomes a target amount.

[0064] The LUT 623 is used for image adjustment processing, which will be described later. The LUT 623 indicates the correspondence relationship between the setting value of the maximum density of the image and the maximum amount of toner adhesion. The LUT 623 also indicates the adjustment range in which the user can adjust the maximum amount of toner adhesion. In the following description, the adjustment range in which the user can adjust the maximum amount of toner adhesion is referred to as the "toner adhesion amount adjustment range." The LUT 623 includes a first LUT 623a and a second LUT 623b.

[0065] Print coverage information 624 indicates the print coverage of a print job input to image forming apparatus 100. Print coverage indicates the amount of toner consumed per sheet in the print job. Print coverage information 624 is an example of "image forming apparatus usage history information" in this disclosure.

[0066] The information 625 on the number of copies to be printed indicates the number of copies to be printed for a print job input to the image forming apparatus 100. The information 625 on the number of copies to be printed is an example of "image forming apparatus usage history information" in this disclosure.

[0067] The RAM 630 forms a work area for temporarily storing various programs executed by the control unit 610 and various data related to these programs.

[0068] The HDD 640 stores and reads image data based on instructions from the control unit 610 .

[0069] The reading processing unit 650 performs various processes such as analog processing, A / D conversion processing, and shading processing on the analog image signal input from the image reading unit 4 to generate digital image data. The reading processing unit 650 performs compression processing on the digital image data and outputs the compressed image data to the DRAM control IC 660.

[0070] The DRAM control IC 660 performs decompression processing of compressed image data according to instructions from the control unit 610. The DRAM control IC 660 also inputs and outputs image data to and from the image memory 670 according to instructions from the control unit 610.

[0071] For example, when the DRAM control IC 660 receives an instruction to save an image acquired by the image reading unit 4 from the control unit 610, the DRAM control IC 660 stores the image data compressed by the reading processing unit 650 (compressed image data) in the image memory 670.

[0072] Furthermore, when the DRAM control IC 660 receives a print instruction for the compressed image data from the control unit 610, the DRAM control IC 660 reads out the compressed image data and performs decompression processing. Then, the DRAM control IC 660 stores the decompressed image data in the image memory 670. Furthermore, when the DRAM control IC 660 receives a print instruction for the decompressed image data from the control unit 610, the DRAM control IC 660 reads out the image data and outputs it to the write processing unit 680. The image memory 670 is formed of, for example, a volatile storage device such as a DRAM.

[0073] The write processing unit 680 outputs the decompressed image data to the printer engine 111.

[0074] The printing unit 8 performs electrophotographic image formation processing based on the image data input from the writing processing unit 680. The printing unit 8 includes a printer engine 111 and an engine control unit 112. The engine control unit 112 controls the operation of each unit of the printer engine 111 according to control signals from the control unit 610.

[0075] The printer controller 7 will now be described. When the image forming apparatus 100 is used as a network printer, the printer controller 7 manages and controls data input to the image forming apparatus 100 from an external device 500 connected to the network. The printer controller 7 includes a controller control unit 71, a DRAM control IC 72, an image memory 73, and a LAN interface 74.

[0076] The controller control unit 71 comprehensively controls the operation of each unit of the printer controller 7. The controller control unit 71 performs language analysis and rasterization processing of the data to be printed that is input from the external device 500 via the LAN interface 74. The controller control unit 71 also generates job data indicating the image formation conditions for a job, and image data, and outputs them to the DRAM control IC 72.

[0077] The DRAM control IC 72 stores data received via the LAN interface 74 in the image memory 73. The DRAM control IC 72 also stores job data and image data generated by the controller control unit 71 in the image memory 73. The DRAM control IC 72 also reads data from the image memory 73. The DRAM control IC 72 is connected to the DRAM control IC 660 of the image control board 6 via a PCI (Peripheral Components Interconnect) bus. The DRAM control IC 72 reads job data and image data from the image memory 73 and outputs them to the DRAM control IC 660 in accordance with instructions from the controller control unit 71.

[0078] The image memory 73 is configured with a volatile storage device such as a DRAM. The LAN interface 74 is a communication interface for connecting to a network. The LAN interface 74 receives data from the external device 500. The received data is output to the DRAM control IC 72.

[0079] <b 使用者権限モード> The user authority modes of the image forming apparatus 100 will be described. The image forming apparatus 100 has a plurality of user authority modes. The plurality of user authority modes include a service mode and a normal mode. The service mode is an example of a "first user authority mode" in this disclosure. The normal mode is an example of a "second user authority mode" in this disclosure.

[0080] The service mode is a mode that is mainly used by service personnel when performing maintenance on the image forming apparatus 100. In other words, the service mode is a mode that is used by those who have technical knowledge of image forming apparatuses. In the service mode, the user can, for example, perform image adjustment using the image adjustment function. In addition, in the service mode, the user can perform other adjustments of the machine, set various functions, check the program version, and upgrade the program version. In addition, in the service mode, the user can output charts for special purposes such as list prints or test charts.

[0081] The normal mode is a mode that is mainly used by general users when printing a desired image on a recording sheet S. In other words, the normal mode is a mode that is used by people who do not have technical knowledge of image forming devices. In the normal mode, the user can, for example, print a desired image on a recording sheet S. In addition, in the normal mode, the user can make various user settings. Furthermore, in the normal mode, the user can make image adjustments using an image adjustment function.

[0082] The image adjustment function includes a maximum density adjustment function. The maximum density adjustment function is a function for adjusting the maximum density of an image. Image density depends on the amount of toner adhesion. Therefore, the maximum density adjustment function can also be said to be a function for adjusting the maximum amount of toner adhesion. The maximum amount of toner adhesion is an example of an "image adjustment parameter" in the present disclosure.

[0083] The image adjustment function may further include a line width adjustment function for adjusting the thickness of lines. The image adjustment function may further include a printing position adjustment function for adjusting the printing position.

[0084] <C Image Adjustment Processing> Referring to FIGS. 3 to 10, the image density adjustment processing of the image forming apparatus 100 will be described. The image density adjustment processing is a process for adjusting the image density. The image density adjustment processing is an example of the image adjustment processing of the image forming apparatus 100.

[0085] (c1 Outline of Image Density Adjustment Processing) Referring to FIGS. 3 and 4, the outline of the image density adjustment processing will be described. FIG. 3 is a diagram showing the outline of the image density adjustment processing of the image forming apparatus 100. The image forming apparatus 100 includes an operation panel 5, a reception unit 611, a setting unit 612, an execution unit 613, and a non-volatile memory 620. The reception unit 611, the setting unit 612, and the execution unit 613 are realized by the control unit 610 executing a program 621.

[0086] When using the image forming apparatus 100, the user operates the operation panel 5 to specify one user authority mode from among a plurality of user authority modes that the image forming apparatus 100 has. The reception unit 611 receives the user authority mode specified by the user. In the following description, the user authority mode specified by the user is referred to as the "target user authority mode".

[0087] In the scene of adjusting the image density, the user operates the operation panel 5 to specify the maximum density of the image. Here, referring to FIG. 4, the method of specifying the maximum density of the image by the user will be described.

[0088] 4 is a diagram showing an example of a screen for specifying the maximum density of an image in image forming apparatus 100. Screen G1 is an example of a screen for specifying the maximum density of an image in image forming apparatus 100. Screen G1 is a common screen regardless of the user authority mode of image forming apparatus 100. In other words, screen G1 is a common screen in the service mode and the normal mode. Screen G1 is displayed on operation panel 5.

[0089] Screen G1 includes image J1. Image J1 shows the current setting value of maximum density. The initial value of maximum density is zero. In the example shown in Fig. 4, maximum density is set to the initial value of zero.

[0090] Furthermore, image J1 shows the range in which the maximum density setting can be set. In the example shown in Figure 4, the range in which the maximum density setting can be set is from -10 to +10.

[0091] Screen G1 further includes operation buttons b1 to b4 for the user to specify a setting value for the maximum density. Setting section 612 (see FIG. 3) accepts the setting value for the maximum density specified by the user's operation.

[0092] For example, when the user presses the operation button b1 once, the setting unit 612 decreases the current setting value of the maximum density by a predetermined amount. When the user presses the operation button b2 once, the setting unit 612 increases the current setting value of the maximum density by a predetermined amount. The predetermined amount is, for example, 1.

[0093] When the user presses the operation button b3, the setting unit 612 changes the current setting value of the maximum density to the minimum setting value.When the user presses the operation button b4, the setting unit 612 changes the current setting value of the maximum density to the maximum setting value.

[0094] Referring again to FIG. 3, the setting unit 612 receives a setting value of the maximum density designated by the user. The setting unit 612 acquires a target user authority mode from the receiving unit 611. The setting unit 612 sets a toner adhesion amount adjustment range according to a target user authority mode currently designated among a plurality of user authority modes. The toner adhesion amount adjustment range differs between the service mode and the normal mode. The toner adhesion amount adjustment range in the normal mode may always be different from the toner adhesion amount adjustment range in the service mode. Alternatively, the toner adhesion amount adjustment range in the normal mode may be different from the toner adhesion amount adjustment range in the service mode only when a predetermined condition is satisfied in the normal mode. The predetermined condition is a condition under which fixing offset or tacking, which induces a risk (such as a decrease in image quality) associated with image adjustment, is likely to occur. Fixing offset and tacking will be described later.

[0095] In the following description, the setting of the toner adhesion amount adjustment range by the setting unit 612 is referred to as a “setting process.” The setting process is a process of selecting one LUT from a plurality of LUTs.

[0096] Here, the first LUT 623a and the second LUT 623b will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing an example of the first LUT 623a. Fig. 6 is a diagram showing an example of the second LUT 623b.

[0097] 5 and 6, the first LUT 623a and the second LUT 623b each indicate a correspondence relationship between a maximum density setting value of an image and a maximum amount of toner adhesion. In addition, the first LUT 623a and the second LUT 623b each indicate a toner adhesion amount adjustment range. However, the toner adhesion amount adjustment range is different between the first LUT 623a and the second LUT 623b.

[0098] In the first LUT 623a, the toner adhesion amount adjustment range is from "T minus 2.0" to "T plus 2.0." That is, in the first LUT 623a, the width of the toner adhesion amount adjustment range is 4.0.

[0099] On the other hand, in the second LUT 623b, the toner adhesion amount adjustment range is from "T minus 2.0" to "T plus 1.0." That is, in the second LUT 623b, the width of the toner adhesion amount adjustment range is 3.0.

[0100] In this way, the toner adhesion amount adjustment range differs between the first LUT 623a and the second LUT 623b. The width of the toner adhesion amount adjustment range in the second LUT 623b is narrower than the width of the toner adhesion amount adjustment range in the first LUT 623a. The toner adhesion amount adjustment range in the second LUT 623b is included in the toner adhesion amount adjustment range in the first LUT 623a. The upper limit of the toner adhesion amount adjustment range in the second LUT 623b is lower than the upper limit of the toner adhesion amount adjustment range in the first LUT 623a.

[0101] Due to such a difference between the first LUT 623a and the second LUT 623b, the toner adhesion amount adjustment range differs between the case where the first LUT 623a is selected and the case where the second LUT 623b is selected. The width of the toner adhesion amount adjustment range when the second LUT 623b is selected is narrower than the width of the toner adhesion amount adjustment range when the first LUT 623a is selected. The toner adhesion amount adjustment range when the second LUT 623b is selected is included in the toner adhesion amount adjustment range when the first LUT 623a is selected. The upper limit of the toner adhesion amount adjustment range when the second LUT 623b is selected is lower than the upper limit of the toner adhesion amount adjustment range when the first LUT 623a is selected. Note that the numerical values ​​shown in FIG. 5 and FIG. 6 are merely examples and are not limited thereto.

[0102] Referring again to FIG. 3, after the setting process, the setting unit 612 determines the maximum amount of toner adhesion. More specifically, the setting unit 612 acquires the maximum amount of toner adhesion corresponding to the setting value of the maximum density designated by the user from the selected LUT 623. As an example, when the setting value of the maximum density designated by the user is "10" and the LUT selected by the setting process is LUT 623a, the setting unit 612 determines the maximum amount of toner adhesion to be "T plus 2.0" (see FIG. 5). On the other hand, when the setting value of the maximum density designated by the user is "10" and the LUT selected by the setting process is LUT 623b, the setting unit 612 determines the maximum amount of toner adhesion to be "T plus 1.0" (see FIG. 6).

[0103] The execution unit 613 sets the maximum toner adhesion amount determined by the setting unit 612 as a target toner adhesion amount in the toner adhesion amount control. The execution unit 613 performs the toner adhesion amount control based on the target toner adhesion amount.

[0104] (c2 Setting process example) 3, 5, and 6, a description will be given of an example of the setting process by the setting unit 612. There are three examples of the setting process by the setting unit 612 as follows.

[0105] In a first example, the setting unit 612 sets the toner adhesion amount adjustment range based on a target user authority mode. In a second example and a third example, the setting unit 612 sets the toner adhesion amount adjustment range based on a target user authority mode and usage history information of the image forming apparatus 100.

[0106] A first example will be described. In the first example, the setting unit 612 selects one LUT from among a plurality of LUTs stored in the non-volatile memory 620 based on the target user authority mode. More specifically, when the target user authority mode is the service mode, the setting unit 612 selects the first LUT 623a. On the other hand, when the target user authority mode is the normal mode, the setting unit 612 selects the second LUT 623b.

[0107] By such selection, the toner adhesion amount adjustment range differs between the service mode and the normal mode. The width of the toner adhesion amount adjustment range in the normal mode is narrower than the width of the toner adhesion amount adjustment range in the service mode. The toner adhesion amount adjustment range in the normal mode is included in the toner adhesion amount adjustment range in the service mode. The upper limit of the toner adhesion amount adjustment range in the normal mode is lower than the upper limit of the toner adhesion amount adjustment range in the service mode.

[0108] A second example will be described. In the second example, the setting unit 612 selects one LUT from among the multiple LUTs stored in the non-volatile memory 620 based on the target user authority mode and the print coverage information 624. More specifically, when the target user authority mode is the service mode, the setting unit 612 selects the first LUT 623a. On the other hand, when the target user authority mode is the normal mode, the setting unit 612 calculates the average value of the print coverage based on the print coverage information 624, and selects an LUT based on the average value. When the average value of the print coverage exceeds the threshold, the setting unit 612 sets the upper limit of the toner adhesion amount adjustment range lower than when the average value of the print coverage is equal to or less than the threshold.

[0109] More specifically, when the target user authority mode is the normal mode and the average value of print coverage exceeds the threshold, the setting unit 612 selects the second LUT 623b. On the other hand, when the target user authority mode is the normal mode and the average value of print coverage is equal to or less than the threshold, the setting unit 612 selects the first LUT 623a. The condition that the average value of print coverage exceeds the threshold is an example of the above-mentioned "predetermined condition."

[0110] By such a selection, in the normal mode, when the average value of print coverage exceeds the threshold value, a range different from that in the service mode is set as the toner adhesion amount adjustment range. In the normal mode, the width of the toner adhesion amount adjustment range when the average value of print coverage exceeds the threshold value is narrower than the width of the toner adhesion amount adjustment range in the service mode. In the normal mode, the toner adhesion amount adjustment range when the average value of print coverage exceeds the threshold value is included in the toner adhesion amount adjustment range in the service mode. In the normal mode, the upper limit of the toner adhesion amount adjustment range when the average value of print coverage exceeds the threshold value is lower than the upper limit of the toner adhesion amount adjustment range in the service mode. In the normal mode, the upper limit of the toner adhesion amount adjustment range when the average value of print coverage exceeds the threshold value is lower than the upper limit of the toner adhesion amount adjustment range when the average value of print coverage is equal to or less than the threshold value.

[0111] A third example will be described. In the third example, the setting unit 612 selects one LUT from among the multiple LUTs stored in the non-volatile memory 620 based on the target user authority mode and the information 625 on the number of printed copies. More specifically, when the target user authority mode is the service mode, the setting unit 612 selects the first LUT 623a. On the other hand, when the target user authority mode is the normal mode, the setting unit 612 calculates the average number of printed copies based on the information 625 on the number of printed copies, and selects an LUT based on the average value. When the average number of printed copies exceeds the threshold value, the setting unit 612 sets the upper limit of the toner adhesion amount adjustment range lower than when the average number of printed copies is equal to or less than the threshold value.

[0112] More specifically, when the target user authority mode is the normal mode and the average number of printed copies exceeds the threshold, the setting unit 612 selects the second LUT 623b. On the other hand, when the target user authority mode is the normal mode and the average number of printed copies is equal to or less than the threshold, the setting unit 612 selects the first LUT 623a. The condition that the average number of printed copies exceeds the threshold is an example of the above-mentioned "predetermined condition."

[0113] By such a selection, in the normal mode, when the average number of printed copies exceeds the threshold value, a range different from that in the service mode is set as the toner adhesion amount adjustment range. In the normal mode, the width of the toner adhesion amount adjustment range when the average number of printed copies exceeds the threshold value is narrower than the width of the toner adhesion amount adjustment range in the service mode. In the normal mode, the toner adhesion amount adjustment range when the average number of printed copies exceeds the threshold value is included in the toner adhesion amount adjustment range in the service mode. In the normal mode, the upper limit of the toner adhesion amount adjustment range when the average number of printed copies exceeds the threshold value is lower than the upper limit of the toner adhesion amount adjustment range in the service mode. In the normal mode, the upper limit of the toner adhesion amount adjustment range when the average number of printed copies exceeds the threshold value is lower than the upper limit of the toner adhesion amount adjustment range when the average number of printed copies is equal to or less than the threshold value.

[0114] Generally, in order to increase the image density, it is necessary to increase the amount of toner adhered to the image. However, when the amount of toner adhered to the image is increased, at least one of fixing offset and tacking occurs.

[0115] Fixing offset is a phenomenon in which, when the amount of toner adhesion exceeds the fixing capacity of the fixing unit 3, at least a part of the toner is not fixed to the recording sheet and the part adheres to the pressure roller 32 of the fixing unit 3. Generally, a document mainly composed of text has low print coverage, while a document mainly composed of graphics and photos has high print coverage. When the coverage is low, the amount of toner adhesion is low, and when the coverage is high, the amount of toner adhesion is high. Therefore, when the coverage is high, fixing offset is likely to occur. Fixing offset significantly reduces image quality and damages the fixing unit 3.

[0116] Tacking is a phenomenon in which a toner image adheres to an adjacent recording sheet, causing the adjacent recording sheets to stick together. When a large number of copies are printed, tacking is likely to occur on the paper discharge tray. For example, when tacking occurs when a large number of recording sheets are stacked on the paper discharge tray, paper alignment becomes poor. In addition, when tacking occurs when a large number of recording sheets are stacked on the paper discharge tray, the toner image adhered to the adjacent recording sheet peels off, degrading image quality.

[0117] Both the fixing offset and tacking are likely to occur when the amount of toner adhesion is excessive. The service person has knowledge about the relationship between the amount of toner adhesion and the fixing offset, and the relationship between the amount of toner adhesion and tacking. Therefore, the service person can adjust the maximum density appropriately according to the usage situation of the image forming apparatus 100, taking into consideration the risks associated with image adjustment. However, general users do not have such knowledge. Therefore, when general users want to increase the image density, they may excessively increase the setting value of the maximum density. In such a case, at least one of the fixing offset and tacking occurs, causing a decrease in image quality or damage to the fixing unit 3.

[0118] However, according to the first example of the setting process, the toner adhesion amount adjustment range is always different between the service mode and the normal mode. The width of the toner adhesion amount adjustment range in the normal mode is narrower than the width of the toner adhesion amount adjustment range in the service mode. Therefore, in the normal mode, the amount of toner adhesion is unlikely to become excessive, and the occurrence of fixing offset and tacking is suppressed. Therefore, when a person without technical knowledge of image forming devices performs image adjustment, the image forming apparatus 100 can suppress the risks associated with image adjustment, such as deterioration of image quality.

[0119] Also, according to the second or third example of the setting process, the toner adhesion amount adjustment range in the normal mode when a predetermined condition is satisfied is different from the toner adhesion amount adjustment range in the service mode. In the normal mode, the width of the toner adhesion amount adjustment range in the normal mode when a predetermined condition is satisfied is narrower than the width of the toner adhesion amount adjustment range in the service mode. Therefore, in the normal mode, the amount of toner adhesion is unlikely to become excessive, and the occurrence of fixing offset and tacking is suppressed. Therefore, the image forming apparatus 100 can suppress the risks associated with image adjustment, such as deterioration of image quality, when an image adjustment is performed by a person who does not have technical knowledge of image forming apparatuses.

[0120] (c3 Toner adhesion amount control) The toner adhesion amount control performed by execution unit 613 will be described with reference to FIG. 3 and FIG. 7 to FIG. 10. The toner adhesion amount control includes four steps. The first step is to form a plurality of test patches. The second step is to calculate the toner adhesion amount of each test patch. The third step is to calculate an approximation formula showing the relationship between the development bias and the toner adhesion amount. The fourth step is to calculate the development bias that provides a target toner adhesion amount. Execution unit 613 performs the toner adhesion amount control when a specific condition is met. The specific condition is determined in advance.

[0121] The first step will be described with reference to Fig. 3, Fig. 7, and Fig. 8. Fig. 7 is a plan view showing a test patch arranged on the intermediate transfer belt 25. Fig. 8 is a side view showing a test patch arranged on the intermediate transfer belt 25.

[0122] 3, 7, and 8, the execution unit 613 causes the process units of the colors that are the targets of the toner adhesion amount control to form a plurality of test patches on the intermediate transfer belt 25. In the example shown in Fig. 7 and Fig. 8, the execution unit 613 causes the process units of the colors that are the targets of the toner adhesion amount control to form test patch P1, test patch P2, test patch P3, and test patch P4 in this order on the intermediate transfer belt 25. The test patches P1, P2, P3, and P4 are test patches made of toner of the color that is the target of the toner adhesion amount control among yellow, magenta, cyan, and black.

[0123] The test patches P1, P2, P3, and P4 are formed by the process units of the colors that are the targets of the toner adhesion amount control. For example, when the color that is the target of the toner adhesion amount control is yellow, the test patches P1, P2, P3, and P4 are formed by the process unit 10Y. More specifically, the yellow test patches P1, P2, P3, and P4 are formed by developing an electrostatic latent image formed on the surface of the photoconductor drum 11Y with toner by the developer 14Y, and transferring the developed toner image to the intermediate transfer belt 25.

[0124] The size of each of the test patches P1, P2, P3, and P4 is sufficiently larger than the aperture size of the detector SE. For example, the length of each test patch in the direction d1 is 10 mm, and the length of each test patch in the direction d2 is 40 mm. The test patches P1, P2, P3, and P4 are formed with the same charging bias and the same exposure amount. On the other hand, the test patches P1, P2, P3, and P4 are formed by developing with different developing biases.

[0125] The test patches P1, P2, P3, and P4 are transported in the direction indicated by the arrow A1 by the rotation of the intermediate transfer belt 25 to a position facing the detector SE. The detector SE detects the amount of toner adhesion (the amount of toner contained in each test patch) in each of the test patches P1, P2, P3, and P4 in this order. In the example shown in Figures 7 and 8, the detector SE detects the amount of toner adhesion in the test patch P1.

[0126] The detector SE includes a light-emitting element LE and a light-receiving element RE. The light-emitting element LE is, for example, a light-emitting diode. The light-emitting element LE obliquely irradiates, for example, visible light or infrared light onto the surface of the intermediate transfer belt 25. The light-receiving element RE is, for example, a photodiode. The light-receiving element RE receives reflected light from the surface of the intermediate transfer belt 25.

[0127] The detector SE may further include a light-emitting lens attached to the light-emitting element LE, a light-receiving lens attached to the light-receiving element RE, etc. The number of test patches is arbitrary.

[0128] The second step will be described with reference to Figures 3 and 9. Figure 9 is a graph showing an example of the relationship between the output voltage of the detector SE and the amount of toner attached to the surface of the intermediate transfer belt 25.

[0129] 3 and 9, in the graph of Fig. 9, the horizontal axis indicates the amount of toner attached to the surface of intermediate transfer belt 25, and the vertical axis indicates the output voltage of detector SE. As the graph of Fig. 9 shows, as the amount of toner attached to the surface of intermediate transfer belt 25 increases, the output voltage of detector SE decreases. This is because, when a large amount of toner is attached to the surface of intermediate transfer belt 25, light from light emitting element LE is absorbed or diffused by the toner, and the amount of light reflected from the surface of intermediate transfer belt 25 decreases.

[0130] In the non-volatile memory 620, information indicating the relationship between the output voltage of the detector SE and the amount of toner attached to the surface of the intermediate transfer belt 25 shown in FIG.

[0131] The execution unit 613 selects one test patch from the test patches P1, P2, P3, and P4, and calculates the average value of the output voltages sequentially output from the detector SE when the test patch is detected. Next, the execution unit 613 calculates the toner adhesion amount in the test patch by converting the average value of the output voltage into the toner adhesion amount using the related information 622. Similarly, the execution unit 613 calculates the toner adhesion amount for each of the remaining test patches.

[0132] With reference to FIGS. 3 and 10, the third step and the fourth step will be described. FIG. 10 is a graph showing an example of the relationship between the developing bias and the toner adhesion amount on the surface of the intermediate transfer belt 25.

[0133] With reference to FIGS. 3 and 10, in the graph shown in FIG. 10, the horizontal axis represents the developing bias, and the vertical axis represents the toner adhesion amount on the surface of the intermediate transfer belt 25. In the graph shown in FIG. 10, the coordinates of the test patches P1, P2, P3, and P4 are shown as coordinates PP1, PP2, PP3, and PP4, respectively.

[0134] The magnitude relationship of the developing bias V1 of the test patch P1, the developing bias V2 of the test patch P2, the developing bias V3 of the test patch P3, and the developing bias V4 of the test patch P4 is V1 < V2 < V3 < V4. The magnitude relationship of the toner adhesion amount M1 in the test patch P1, the toner adhesion amount M2 in the test patch P2, the toner adhesion amount M3 in the test patch P3, and the toner adhesion amount M4 in the test patch P4 is M1 < M2 < M3 < M4.

[0135] The execution unit 613 calculates an approximation formula LN1 using the least squares method based on the coordinates PP1, PP2, PP3, and PP4. More specifically, the execution unit 613 calculates an approximation formula LN1 showing the relationship between the developing bias and the toner adhesion amount on the surface of the intermediate transfer belt 25 using the least squares method based on the values of the developing biases and the toner adhesion amounts of the test patches P1, P2, P3, and P4 (third step).

[0136] Next, the execution unit 613 calculates a development bias at which the target toner adhesion amount can be obtained using the approximate formula LN1 (the fourth step). Finally, the execution unit 613 stores this calculation result in the non-volatile memory 620. The calculation result is used as the development bias at the time of image formation after the next time. As described above, the target toner adhesion amount is the maximum toner adhesion amount determined by the setting unit 612. As described above, the maximum toner adhesion amount is determined based on the set value of the maximum density specified by the user and the target user authority mode. Alternatively, the maximum toner adhesion amount is determined based on the set value of the maximum density specified by the user, the target user authority mode, and the usage history information of the image forming apparatus 100.

[0137] <D effect> As described above, the image forming apparatus 100 in the present embodiment has a plurality of user authority modes including a first user authority mode and a second user authority mode. The first user authority mode is a mode used by a person having technical knowledge of the image forming apparatus. The second user authority mode is a mode used by a person who does not have technical knowledge of the image forming apparatus. In the image forming apparatus 100 in the present embodiment, the adjustment range that the user can adjust for the image adjustment parameters is different between the first user authority mode and the second user authority mode. Therefore, the image forming apparatus 100 in the present embodiment can suppress the risk associated with image adjustment when a person who does not have technical knowledge of the image forming apparatus performs image adjustment.

[0138] Conventional image forming apparatuses control the amount of toner adhesion so that each of the colors yellow, magenta, cyan, and black has a density targeted by the manufacturer of the image forming apparatus. In contrast, the image forming apparatus 100 of the present embodiment uses the maximum amount of toner adhesion corresponding to the maximum density setting value designated by the user as the target amount of toner adhesion in the toner adhesion amount control. Therefore, the image forming apparatus 100 of the present embodiment allows the user to adjust the image density to the user's preferred density. Also, the image forming apparatus 100 of the present embodiment allows the user to reduce the amount of toner used by setting the image density setting value low.

[0139] [Variation 1] In the above embodiment, the toner adhesion amount adjustment range in the second LUT 623b is completely included in the toner adhesion amount adjustment range in the first LUT 623a, but this is not limiting.

[0140] As another example, the width of the toner adhesion amount adjustment range in the second LUT 623b is narrower than the width of the toner adhesion amount adjustment range in the first LUT 623a, but a part of the toner adhesion amount adjustment range in the second LUT 623b may not be included in the toner adhesion amount adjustment range in the first LUT 623a. For example, the toner adhesion amount adjustment range in the first LUT 623a may be in the range from "T minus 2.0" to "T plus 2.0", and the toner adhesion amount adjustment range in the second LUT 623b may be in the range from "T minus 2.1" to "T plus 0.9". As a result, the width of the toner adhesion amount adjustment range when the second LUT 623b is selected is narrower than the width of the toner adhesion amount adjustment range when the first LUT 623a is selected, but a part of the toner adhesion amount adjustment range when the second LUT 623b is selected is not included in the toner adhesion amount adjustment range when the first LUT 623a is selected.

[0141] As another example, the width of the toner adhesion amount adjustment range in the second LUT 623b may be narrower than the width of the toner adhesion amount adjustment range in the first LUT 623a, but the toner adhesion amount adjustment range in the second LUT 623b may not be included at all in the toner adhesion amount adjustment range in the first LUT 623a. As a result, the width of the toner adhesion amount adjustment range when the second LUT 623b is selected is narrower than the width of the toner adhesion amount adjustment range when the first LUT 623a is selected, but the toner adhesion amount adjustment range when the second LUT 623b is selected is not included at all in the toner adhesion amount adjustment range when the first LUT 623a is selected.

[0142] [Variation 2] In the second and third examples of the setting process, the toner adhesion amount adjustment range in the normal mode when the specified conditions are not met is the same as the toner adhesion amount adjustment range in the service mode. However, the toner adhesion amount adjustment range in the normal mode when the specified conditions are not met may be different from the toner adhesion amount adjustment range in the service mode.

[0143] In this case, the non-volatile memory 620 further stores a third LUT. The width of the toner adhesion amount adjustment range when the third LUT is selected is narrower than the width of the toner adhesion amount adjustment range when the first LUT 623a is selected, and is wider than the width of the toner adhesion amount adjustment range when the second LUT 623b is selected. When the target user authority mode is the service mode, the setting unit 612 selects the first LUT 623a. When the target user authority mode is the normal mode and a predetermined condition is satisfied, the setting unit 612 selects the second LUT 623b. When the target user authority mode is the normal mode and a predetermined condition is not satisfied, the setting unit 612 selects the third LUT.

[0144] As a result, the toner adhesion amount adjustment range differs between when the predetermined condition is met in the normal mode, when the predetermined condition is not met in the normal mode, and in the service mode.

[0145] [Variation 3] In the second and third examples of the setting process, only when the target user authority mode is the normal mode, setting unit 612 sets the toner adhesion amount adjustment range based on the usage history information of image forming apparatus 100. However, setting unit 612 may also set the toner adhesion amount adjustment range based on the usage history information of image forming apparatus 100 when the target user authority mode is the service mode.

[0146] [Variation 4] In the above embodiment, the image forming apparatus 100 has two user authority modes, the service mode and the normal mode, but the two user authority modes are not limited to the service mode and the normal mode. The two user authority modes are arbitrarily selected from the service mode, the normal mode, the administrator mode used by the administrator who manages the machine, and the installer mode used by the worker who installs the machine, etc.

[0147] Image forming apparatus 100 may have three or more user authority modes. In that case, setting unit 612 may set a different range for each user authority mode as the adjustment range in which the user can adjust the image adjustment parameters. As an example, when the multiple user authority modes of image forming apparatus 100 include a service mode, an administrator mode, and a normal mode, setting unit 612 sets the adjustment range in which the user can adjust the image adjustment parameters so that the following relationship is satisfied:

[0148] The width of the adjustment range in the normal mode is narrower than the width of the adjustment range in the administrator mode, and the width of the adjustment range in the administrator mode is narrower than the width of the adjustment range in the service mode. In this example, the service mode is an example of a "first user authority mode" in the present disclosure. In this example, the normal mode is an example of a "second user authority mode" in the present disclosure. In this example, the administrator mode is an example of a "third user authority mode" in the present disclosure.

[0149] In addition, even if the image forming apparatus 100 has three or more user authority modes, the setting unit 612 may set the adjustment range based on the usage history information of the image forming apparatus 100 if the target user authority mode is any one or more specified user authority modes among the multiple user authority modes.

[0150] [Variation 5] In the above embodiment, the maximum amount of toner adhesion is taken as an example of an image adjustment parameter, and a case where a user can set an adjustment range for the maximum amount of toner adhesion is described. However, the image adjustment parameter is not limited to the maximum amount of toner adhesion.

[0151] The image adjustment parameter may be a line width. Adjusting the line width is a task that requires careful attention. If the line width is not adjusted appropriately, there are risks associated with the image adjustment, such as a decrease in image quality. In a manner similar to the above embodiment, the setting unit 612 may set an adjustment range for the line width that can be adjusted by the user.

[0152] The image adjustment parameter may be the print position. Adjusting the print position is a task that requires careful attention. If the print position is not adjusted appropriately, there are risks associated with the image adjustment, such as a decrease in image quality. In a similar manner to the above embodiment, the setting unit 612 may set an adjustment range for the print position that can be adjusted by the user.

[0153] [Variation 6] In the above embodiment, image forming apparatus 100 is a color printer, but it may also be a monochrome printer.

[0154] [Note] The above-described embodiment and modified examples include the following technical ideas.

[0155] [Configuration 1] 1. An image forming apparatus having a plurality of user authority modes, a setting unit that sets an adjustment range that a user can adjust for an image adjustment parameter according to a currently designated target user authority mode among the plurality of user authority modes; the plurality of user authority modes include a first user authority mode and a second user authority mode; The adjustment range differs between the first user authority mode and the second user authority mode.

[0156] [Configuration 2] 2. The image forming apparatus according to claim 1, wherein the width of the adjustment range in the second user authority mode is narrower than the width of the adjustment range in the first user authority mode.

[0157] [Configuration 3] 3. The image forming apparatus according to claim 2, wherein the adjustment range in the second user authority mode is included in the adjustment range in the first user authority mode.

[0158] [Configuration 4] the image forming apparatus further includes a storage unit that stores usage history information of the image forming apparatus; The image forming apparatus according to any one of configurations 1 to 3, wherein the setting unit sets the adjustment range based on the usage history information when the target user authority mode is any one of one or more specified user authority modes among the plurality of user authority modes.

[0159] [Configuration 5] the image forming apparatus forms an image on a sheet using a toner; 5. The image forming apparatus according to claim 4, wherein the image adjustment parameters include a maximum toner adhesion amount.

[0160] [Configuration 6] 6. The image forming apparatus according to claim 5, wherein the usage history information includes information on print coverage.

[0161] [Configuration 7] the one or more predetermined user authority modes include the second user authority mode; 7. The image forming apparatus according to configuration 6, wherein the setting unit sets an upper limit of the adjustment range of the maximum adhesion amount lower when the print coverage exceeds a threshold value than when the print coverage is equal to or less than the threshold value.

[0162] [Configuration 8] 6. The image forming apparatus according to claim 5, wherein the usage history information includes information on the number of printed copies.

[0163] [Configuration 9] the one or more predetermined user authority modes include the second user authority mode; 9. The image forming apparatus according to claim 8, wherein the setting unit sets an upper limit of the adjustment range of the maximum adhesion amount lower when the number of printed copies exceeds a threshold value than when the number of printed copies is equal to or less than the threshold value.

[0164] [Configuration 10] the plurality of user authority modes further includes a third user authority mode; a width of the adjustment range in the second user authority mode is narrower than a width of the adjustment range in the third user authority mode; 10. The image forming apparatus according to any one of configurations 1 to 9, wherein a width of the adjustment range in the third user authority mode is narrower than a width of the adjustment range in the first user authority mode.

[0165] [Configuration 11] 1. A method for setting an adjustable range of an image adjustment parameter of an image forming apparatus having a plurality of user authority modes, comprising: setting the adjustment range in response to a currently designated target user authority mode among the plurality of user authority modes; the plurality of user authority modes include a first user authority mode and a second user authority mode; The adjustment range is different between the first user authority mode and the second user authority mode.

[0166] [Configuration 12] A setting program that causes one or more computers to execute the setting method described in configuration 11.

[0167] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0168] 1 image forming unit, 2 paper feed unit, 3 fixing unit, 4 image reading unit, 5 operation panel, 6 image control board, 7 printer controller, 8 printing unit, 9 main body unit, 10C, 10K, 10M, 10Y process unit, 11C, 11K, 11M, 11Y photoconductor drum, 12C, 12K, 12M, 12Y charger, 14C, 14K, 14M, 14Y developer, 16C, 16K, 16M, 16Y cleaning blade, 17C, 17K, 17M, 17Y toner cartridge, 19C, 19K, 19M, 19Y toner supply mechanism, 21 sheet transport path, 22 paper feed cassette, 23, 24 roller, 25 intermediate transfer belt, 26 secondary transfer roller, 27C, 27K, 27M, 27Y Primary transfer roller, 28 Exposure unit, 31 Heating roller, 32 Pressure roller, 33 Heater lamp, 34 Paper discharge roller, 35 Paper discharge tray, 41 Scanner, 42 Image reading control unit, 610 Control unit, 51 Display unit, 52 Operation unit, 53 Operation display control unit, 71 Controller control unit, 72 DRAM control IC, 73 Image memory, 74 LAN interface, 100 Image forming device, 111 Printer engine, 112 Engine control unit, 500 External device, 611 Reception unit, 612 Setting unit, 613 Execution unit, 620 Non-volatile memory, 621 Program, 622 Related information, 623a First LUT, 623b Second LUT, 624 Print coverage information, 625 Number of prints information, 630 RAM, 640 HDD, 650 Reading processing unit, 660 DRAM control IC, 670 Image memory, 680 write processing unit, A1, A2 arrows, G1 screen, J1 image, LC, LK, LM, LY laser light, LE light emitting element, LN1 approximation formula, NW network, P1, P2, P3, P4 test patch, PP1, PP2, PP3, PP4 coordinates, RE light receiving element, S recording sheet, SE detector, b1, b2, b3, b4 operation button, d1, d2 direction.

Claims

1. 1. An image forming apparatus having a plurality of user authority modes, a setting unit that sets an adjustment range that a user can adjust for an image adjustment parameter according to a currently designated target user authority mode among the plurality of user authority modes; the plurality of user authority modes includes a first user authority mode and a second user authority mode; The adjustment range differs between the first user authority mode and the second user authority mode.

2. 2. The image forming apparatus according to claim 1, wherein the width of the adjustment range in the second user authority mode is narrower than the width of the adjustment range in the first user authority mode.

3. The image forming apparatus according to claim 2 , wherein the adjustment range in the second user authority mode is included in the adjustment range in the first user authority mode.

4. the image forming apparatus further includes a storage unit that stores usage history information of the image forming apparatus; The image forming apparatus according to any one of claims 1 to 3, wherein the setting unit sets the adjustment range based on the usage history information when the target user authority mode is one or more specified user authority modes among the plurality of user authority modes.

5. the image forming apparatus forms an image on a sheet using a toner; The image forming apparatus according to claim 4 , wherein the image adjustment parameters include a maximum amount of toner adhesion.

6. The image forming apparatus according to claim 5 , wherein the usage history information includes information on print coverage.

7. the one or more predetermined user authority modes include the second user authority mode; The image forming apparatus according to claim 6 , wherein the setting unit sets the upper limit of the adjustment range of the maximum adhesion amount lower when the print coverage exceeds a threshold value than when the print coverage is equal to or less than the threshold value.

8. The image forming apparatus according to claim 5 , wherein the usage history information includes information on the number of printed copies.

9. the one or more predetermined user authority modes include the second user authority mode; The image forming apparatus according to claim 8 , wherein the setting unit sets the upper limit of the adjustment range of the maximum adhesion amount lower when the number of printed copies exceeds a threshold value than when the number of printed copies is equal to or less than the threshold value.

10. the plurality of user authority modes further includes a third user authority mode; a width of the adjustment range in the second user authority mode is narrower than a width of the adjustment range in the third user authority mode; 2. The image forming apparatus according to claim 1, wherein a width of the adjustment range in the third user authority mode is narrower than a width of the adjustment range in the first user authority mode.

11. 1. A method for setting an adjustable range of an image adjustment parameter of an image forming apparatus having a plurality of user authority modes, comprising: setting the adjustment range in response to a currently designated target user authority mode among the plurality of user authority modes; the plurality of user authority modes includes a first user authority mode and a second user authority mode; The adjustment range is different between the first user authority mode and the second user authority mode.

12. A setting program for causing one or more computers to execute the setting method according to claim 11.

Images