Image forming apparatus and program

Abstract

The present invention provides an image forming apparatus and program capable of accurately determining the deterioration of a photoreceptor. [Solution] According to the embodiment, the image forming apparatus comprises a photoreceptor, a developer, a storage unit, and a processor. An electrostatic latent image is formed on the photoreceptor by light irradiated onto a uniformly charged surface. The developer develops the electrostatic latent image formed on the photoreceptor. The storage unit stores a life setting value for determining when the photoreceptor has reached the end of its lifespan. The processor corrects the life setting value stored in the storage unit according to the actual residual potential and the standard residual potential in the photoreceptor.

Description

Technical Field

[0001] Embodiments of the present invention relate to an image forming apparatus and a program.

Background Art

[0002] Conventionally, an electrophotographic image forming apparatus forms a toner image by developing an electrostatic latent image formed on a photoreceptor with toner. The photoreceptor is cleaned by a cleaner having a cleaning blade after transferring the toner image to a transfer member. In such an image forming apparatus, deterioration such as film wear of the photosensitive layer on the photoreceptor occurs due to cleaning by the cleaner. When the deterioration of the photosensitive layer of the photoreceptor progresses, the image forming apparatus needs to replace the photoreceptor.

[0003] Some conventional image forming apparatuses determine that the photoreceptor has reached its lifespan (replacement time) when an index value such as the number of sheets passed, the driving distance or driving time of the photoreceptor reaches a preset value. However, in actual image forming apparatuses, the deterioration of the photoreceptor often does not progress as expected beforehand. Therefore, if the deterioration of the image forming apparatus progresses faster than expected, the replacement of the photoreceptor that has reached its lifespan may be delayed. Also, if the deterioration of the image forming apparatus progresses slower than expected, there may be a waste of replacing a usable photoreceptor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide an image forming apparatus and a program capable of accurately determining the deterioration of a photoreceptor.

Means for Solving the Problems

[0006] According to one embodiment, the image forming apparatus comprises a photoreceptor, a developer, a memory unit, and a processor. An electrostatic latent image is formed on the photoreceptor by light irradiated onto a uniformly charged surface. The developer develops the electrostatic latent image formed on the photoreceptor. The memory unit stores a life setting value for determining when the photoreceptor has reached the end of its lifespan. The processor corrects the life setting value stored in the memory unit according to the actual residual potential and the standard residual potential of the photoreceptor. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of the configuration of an image forming system including a digital multifunction printer as an image forming apparatus according to the embodiment. [Figure 2] Figure 2 shows an example of the configuration of a digital multifunction device as an image forming apparatus according to the embodiment. [Figure 3] Figure 3 shows an example of the printer configuration in a digital multifunction device as an image forming apparatus according to the embodiment. [Figure 4] Figure 4 is a block diagram showing an example of the control system configuration in a digital multifunction printer as an image forming apparatus according to the embodiment. [Figure 5] Figures 5(a) and 5(b) are diagrams illustrating the various potentials in the image adjustment operation of a digital multifunction printer as an image forming apparatus according to this embodiment. [Figure 6] Figure 6 shows an example of the relationship between the residual potential and degradation index of a photoreceptor drum in a digital multifunction printer, which is an image forming apparatus according to the embodiment. [Figure 7] Figure 7 shows an example of the changes in the actual residual potential and the standard residual potential in a photoreceptor drum of a digital multifunction printer as an image forming apparatus according to the embodiment. [Figure 8] Figure 8 is a flowchart illustrating an example of operation, including degradation detection processing, in a digital multifunction printer as an image forming apparatus according to the embodiment. [Figure 9]Figure 9 is a flowchart illustrating an example of operation, including the correction process for the life setting value, in a digital multifunction printer as an image forming apparatus according to the embodiment. [Figure 10] Figure 10 shows examples of the standard life curve and the corrected life curve for the photoreceptor drum in a digital multifunction printer as an image forming apparatus according to the embodiment. [Figure 11] Figure 11 is a flowchart illustrating an example of operation, including pre-notification processing, in a digital multifunction printer as an image forming apparatus according to the embodiment. [Modes for carrying out the invention]

[0008] This embodiment will be described below with reference to the drawings. Note that the scale of each part has been appropriately changed in the drawings used to describe the following embodiments. Also, for illustrative purposes, some components have been omitted in the drawings used to describe the following embodiments. Figure 1 is a schematic diagram of a printing system (image forming system) including multiple image forming apparatuses 1 according to the embodiment. The printing system including the image forming apparatuses 1 further comprises multiple user terminals 200, a server device 300, and a service technician terminal 400.

[0009] Each image forming apparatus 1 is located in a workplace and is connected to a user terminal 200 located in the same workplace, for example, via an internal network 500 such as a LAN (Local Area Network). This connection may be wired or wireless. The internal network 500 is also connected to an external network 600 such as the Internet. The server device 300 and the service technician terminal 400 are connected to the external network 600. The image forming apparatus 1 is connected to the server device 300 via the internal network 500 and the external network 600.

[0010] The user terminal 200 is an information processing device that instructs printing on any of the image forming apparatuses 1. The user terminal 200 is, for example, an information processing device such as a personal computer (PC), smartphone, tablet terminal, or digital camera. The user terminal 200 may be connected to the image forming apparatus 1 via an external network 600 and an internal network 500. In other words, the user terminal 200 may be located outside the workplace where the image forming apparatus 1 is installed. The user terminal 200 may also be connected directly to the image forming apparatus 1 without going through the external network 600 and the internal network 500. In other words, the user terminal 200 may be locally connected to the image forming apparatus 1. When the user terminal 200 is locally connected to the image forming apparatus 1, the connection may be wired or wireless.

[0011] The server device 300 is a computer device operated either directly or by a service provider by a management company that is contracted to perform maintenance and inspection of the image forming apparatus 1. The server device 300 periodically or as needed acquires maintenance information for each image forming apparatus 1. The maintenance information includes information indicating the operating status of the image forming apparatus 1 (such as the number of sheets fed (number of prints), the drive distance and drive time of the photosensitive drum, the size and type of paper printed), and information indicating the status of each part. The server device 300 may also acquire notification data such as alerts transmitted from the image forming apparatus 1.

[0012] The server device 300 determines the need for inspection or repair (maintenance) of each image forming apparatus 1 based on the acquired data. If there is an image forming apparatus 1 that requires maintenance, the server device 300 transmits information identifying the image forming apparatus 1 that requires maintenance to the service technician terminal 400. When the service technician terminal 400 is notified that an image forming apparatus 1 requires maintenance, the service technician can proceed to perform maintenance on the image forming apparatus 1 according to the notification.

[0013] The server device 300 is an information processing device having a processor 3001, a memory 3002, a communication interface (I / F) 3003, and the like. The processor 3001 is, for example, a CPU. The processor 3001 executes various processes by executing a program stored in the memory 3002. The communication interface 3003 is an interface for communicating with each device via the network 600. The memory 3002 is composed of storage devices such as a ROM, a RAM, and a non-volatile memory. The memory 3002 includes a program memory that stores programs, a working memory that temporarily holds data, and a data memory that accumulates data.

[0014] In the server device 300, the memory 3002 has a storage area that stores a database for storing maintenance information acquired from the image forming apparatus 1 and the like. The processor 3001 of the server device 300 stores information such as maintenance information acquired from the image forming apparatus 1 in the database of the memory 3002. The processor 3001 of the server device 300 determines the necessity of maintenance for each image forming apparatus based on the maintenance information of each image forming apparatus stored in the database.

[0015] The service technician terminal 400 is an information processing device such as a smartphone or a tablet terminal carried by a service technician who performs maintenance on the image forming apparatus 1. In FIG. 1, only one service technician terminal 400 is shown, but the printing system may include a plurality of service technician terminals 400. The service technician terminal 400 may be provided with a position detection function and transmit the position detected by the position detection function to the server device 300 as the position information of the service technician. The server device 300 can also assign an appropriate service technician to the image forming apparatus 1 that requires maintenance based on information such as the position information of each service technician and the availability of each service technician.

[0016] Next, the configuration of a digital multi-functional peripheral (MFP) as an example of the image forming apparatus 1 according to the embodiment will be described. FIG. 2 is a block diagram showing a configuration example of a digital multifunction peripheral as an example of the image forming apparatus 1 according to the embodiment. As shown in FIG. 2, the digital multifunction peripheral as the image forming apparatus 1 includes a printer 2, an operation panel 3, a scanner 4, and a system controller 5.

[0017] The printer 2 is an image forming apparatus that forms an image on a recording medium. In the present embodiment, the printer 2 forms an image on a recording medium by an electrophotographic method. The electrophotographic printer 2 forms an image (toner image) on a recording medium such as paper with toner. The recording medium on which the printer 2 forms an image may be any medium on which an image can be formed, and is not limited to paper, and may be cloth, a plastic film, a sheet, or the like.

[0018] The scanner 4 is installed on the upper part of the main body of the digital multifunction peripheral. The scanner 4 is an apparatus that optically reads an image of a document. For example, the scanner 4 reads an image of a document set on the document table glass. Further, the scanner 4 may be configured to include one that reads an image of a document conveyed by an automatic document feeder (ADF).

[0019] The operation panel 3 is a user interface. The operation panel 3 includes a display unit (display), a touch panel, and operation buttons. The operation panel 3 displays operation guidance and the like on the display unit. The operation panel 3 receives an operation instruction from the user through the touch panel and operation buttons. For example, the operation panel 3 provides a touch panel on the display screen of the display unit and detects a part touched by the user on the display screen of the display unit.

[0020] The system controller 5 controls the entire digital multifunction device, including the image forming apparatus 1. The system controller 5 controls the operation of each part based on operation instructions entered into the control panel 3. The system controller 5 also receives operation instructions from external devices connected via an interface and controls the operation of each part. For example, if the system controller 5 is instructed to form an image on the recording medium, it controls the printer 2 to perform image formation on the recording medium.

[0021] The following describes the configuration of printer 2. As shown in Figure 2, the printer 2 includes a media supply mechanism 13, a transport mechanism 15, multiple image forming stations SY, SM, SC, SK, an intermediate transfer belt (transfer belt) 21, a secondary transfer roller 22, a support roller 23, a toner sensor 24, a transfer belt cleaner 25, and a fuser 26.

[0022] The media supply mechanism 13 has multiple paper feed cassettes 321, 322, and 323. The number of paper feed cassettes can be any number. Each paper feed cassette 321, 322, and 323 stores paper as a recording medium S. The paper as recording medium S stored in each paper feed cassette may be of different sizes or different types. Each paper feed cassette 321, 322, and 323 is equipped with a pickup roller 341, 342, and 343. The pickup rollers 341, 342, and 343 each pick up one sheet of paper as a recording medium from the paper feed cassette 321, 322, and 323. The pickup rollers 341, 342, and 343 each supply the picked-up recording medium S to the transport mechanism 15.

[0023] The transport mechanism 15 transports the recording medium S. In the transport path to the recording medium S before image formation, the transport mechanism 15 has first transport rollers 521, 522, 523, a second transport roller 54, and a registration roller 56. The transport mechanism 15 transports the recording medium S supplied by the pickup rollers 341, 342, 343 from the first transport rollers 521, 522, 523 to the second transport roller 54. In the transport mechanism 15, the second transport roller 54 further transports the recording medium S to the registration roller 56.

[0024] The registration roller 56 of the transport mechanism 15 transports the recording medium S to the secondary transfer position in accordance with the timing of transferring the image from the intermediate transfer belt 21 to the recording medium S at the secondary transfer position, which will be described later. The transport mechanism 15 configures a transport path to transport the recording medium S, on which the image has been transferred from the intermediate transfer belt 21, to the fuser 26. Furthermore, the transport mechanism 15 includes a third transport roller 58 for ejecting paper to the paper discharge section, and a transport mechanism for transporting the recording medium S to the inversion section for inverting the recording medium S.

[0025] Each image forming station SY, SM, SC, and SK forms an image using toner. In this embodiment, image forming station SY forms a yellow image. Image forming station SM forms a magenta image. Image forming station SC forms a cyan image. Image forming station SK forms a black image. Each image forming station SY, SM, SC, and SK transfers the toner-formed image to the intermediate transfer belt 21. The configurations of each image forming station SY, SM, SC, and SK will be described in detail later.

[0026] The intermediate transfer belt 21 is a medium (image carrier) that holds the images transferred by each image forming station SY, SM, SC, and SK. The intermediate transfer belt 21 is an endless belt as shown in Figure 2. The intermediate transfer belt 21 moves in the direction indicated by arrow a in Figure 2. The intermediate transfer belt 21 moves the images transferred by each image forming station SY, SM, SC, and SK to a position where the secondary transfer roller 22 and the support roller 23 face each other.

[0027] The secondary transfer roller 22 and the support roller 23 constitute a transfer section (secondary transfer section) that transfers an image from the intermediate transfer belt 21 to the recording medium. The position where the secondary transfer roller 22 and the support roller 23 face each other is the secondary transfer position where the image is transferred from the intermediate transfer belt 21 to the recording medium. At the secondary transfer position, the secondary transfer roller 22 and the support roller 23 sandwich the intermediate transfer belt 21 and the recording medium.

[0028] The support roller 23 supports the intermediate transfer belt 21. The support roller 23 is a drive roller that drives the intermediate transfer belt 21. The secondary transfer roller 22 faces the support roller 23 across the intermediate transfer belt 21. The secondary transfer roller 22 transfers (secondary transfer) the image formed by the toner on the transfer surface of the intermediate transfer belt 21 onto the surface of the recording medium.

[0029] The toner sensor 24 is a sensor that detects the amount (concentration) of toner. The toner sensor 24 detects the amount of toner adhering to the intermediate transfer belt 21. The toner sensor 24 is positioned opposite the transfer surface of the intermediate transfer belt 21. The toner sensor 24 is installed between the image transfer position (primary transfer position) and the secondary transfer position of each image forming station in the movement direction a of the intermediate transfer belt 21. The toner sensor 24 outputs the detected amount of toner adhering to the system controller 5.

[0030] As shown in Figure 2, the transfer belt cleaner 25 is positioned between the secondary transfer position and the primary transfer position in the direction a of movement of the intermediate transfer belt 21. The transfer belt cleaner 25 removes toner from the intermediate transfer belt 21. For example, the transfer belt cleaner 25 removes any remaining toner on the transfer surface of the intermediate transfer belt 21 after the image has been transferred from the intermediate transfer belt 21 to the recording medium.

[0031] The fuser 26 fixes the image formed by the toner transferred to the recording medium onto the recording medium. The fuser 26 is positioned in the transport path of the recording medium after it has passed the secondary transfer position. The fuser 26 has opposing pressure rollers and heating rollers. The fuser 26 applies heat and pressure to the recording medium by transporting it between the opposing heating rollers and pressure rollers. The fuser 26 fixes the toner image transferred to the recording medium by heating under pressure.

[0032] Next, the configurations of the image forming stations SY, SM, SC, and SK of the printer 2 in the digital multifunction printer, which is the image forming apparatus 1 according to the embodiment, will be described in detail. Figure 3 shows an example configuration of each image forming station SY, SM, SC, and SK in printer 2. Each image forming station SY, SM, SC, and SK includes, as shown in Figure 3, an exposure unit 100, a developer unit 110, a photoreceptor drum 122, a charger 126, a primary transfer roller 128, a photoreceptor cleaner 130, and a static eliminator 132, respectively. In this embodiment, each image forming station SY, SM, SC, and SK has the configuration shown in Figure 3.

[0033] The photoreceptor drum 122 is an image carrier having a photoreceptor layer 124 on its surface. The photoreceptor drum 122 rotates in a direction that matches the movement of the intermediate transfer belt 21 in direction a (the direction indicated by arrow b in Figure 3). Around the photoreceptor drum 122 are a charger 126, an exposure unit 100, a developer unit 110, a primary transfer roller 128, an intermediate transfer belt 21, a photoreceptor cleaner 130, and a static eliminator 132.

[0034] The charger 126 uniformly charges the photoreceptor layer 124 on the surface of the photoreceptor drum 122. For example, the charger 126 uniformly charges the photoreceptor layer 124 on the surface of the photoreceptor drum 122 to a negative polarity. In this embodiment, the charger 126 charges the photoreceptor layer 124 of the photoreceptor drum 122 to a charging potential Vo by a control instruction from the controller 5.

[0035] The exposure unit 100 forms an electrostatic pattern (electrostatic latent image) on the surface of the photoreceptor drum 122 that corresponds to the image. The exposure unit 100 irradiates the surface of the photoreceptor drum 122 with light whose emission is controlled based on the image data. For example, the exposure unit 100 irradiates the surface of the photoreceptor drum 122 with light emitted based on the image data via an optical system such as a polygon mirror. The exposure unit 100 may also include a device that emits multiple laser beams guided to the photoreceptor drums 122 of multiple image forming stations. Alternatively, the exposure unit 100 may be a light-emitting device provided for each of the multiple image forming stations.

[0036] The developer unit 110 develops the electrostatic latent image formed on the surface of the photoreceptor drum 122 with a developer. The developer unit 110 supplies the developer to the surface of the photoreceptor drum 122 that has been exposed by the exposure unit 100. Each developer unit 110 in the image forming station develops the image with its corresponding color. For example, the developer unit 110 in image forming station SY develops the electrostatic latent image on the photoreceptor drum 122 with yellow toner. The developer unit 110 in image forming station SM develops the electrostatic latent image on the photoreceptor drum 122 with magenta toner. The developer unit 110 in image forming station SC develops the electrostatic latent image on the photoreceptor drum 122 with cyan toner. The developer unit 110 in image forming station SK develops the electrostatic latent image on the photoreceptor drum 122 with black toner.

[0037] In the configuration example shown in Figure 3, the developer unit 110 includes a developer container 112, a developer roller 114, a first mixer 116, a second mixer 118, and a toner density sensor 120. The developer container 112 is a container for holding the developer. The developer is a mixture of a carrier made of magnetic fine particles and toner. When the developer is stirred, the toner becomes triboelectrically charged. As a result, the toner adheres to the surface of the carrier by electrostatic force.

[0038] Inside the developer container 112, a developing roller 114, a first mixer 116, a second mixer 118, and a toner density sensor 120 are arranged. The toner concentration sensor 120 is located inside the developer storage section 112. The toner concentration sensor 120 detects the toner concentration in the developer stored in the developer storage section 112. The toner concentration is expressed, for example, as the ratio of toner to carrier (toner / carrier) in the developer in the developer storage section 112. The system controller 5 controls the toner concentration detected by the toner concentration sensor 120 so that it reaches a predetermined value.

[0039] The developing roller 114 has, for example, a magnetic material (e.g., a magnet) in which positive and negative electrodes are arranged alternately along the circumference. The developing roller 114 rotates counterclockwise. The first mixer 116 and the second mixer 118 agitate the developer in the developer container 112. The first mixer 116 and the second mixer 118 also transport the developer. The second mixer 118, located below the developing roller 114, supplies the developer to the surface of the developing roller 114.

[0040] The developer adheres to the surface of the developing roller 114 in a raised state according to the magnetic field distribution generated by the magnetic material of the developing roller 114. The developing roller 114 rotates while carrying the developer. The layer of developer attached to the developing roller 114 is limited to a predetermined thickness by a blade provided so that the gap between the blade and the surface of the developing roller 114 is a predetermined width. The developer carried by the developing roller 114, limited to a predetermined thickness by the blade, moves to a position facing the surface of the photosensitive drum 122 (developing position).

[0041] A developing roller 114, which carries the developer, is subjected to a developing bias. The potential of the surface of the developing roller 114 (developing potential) is controlled by the developing bias. The toner in the developer carried by the developing roller 114 adheres to the electrostatic latent image due to the potential difference (contrast voltage) between the potential of the surface of the developing roller 114 and the potential of the electrostatic latent image formed on the surface of the photoreceptor drum 122. As the developing roller 114 rotates in a predetermined direction, the developer carried by the developing roller 114 approaches the surface of the photoreceptor drum 122 on which the electrostatic latent image is formed. When the toner contained in the developer carried by the developing roller 114 approaches the surface of the photoreceptor drum 122, it develops the electrostatic latent image on the photoreceptor drum 122. As a result, a toner image obtained by developing the electrostatic latent image with toner is formed on the photoreceptor drum 122.

[0042] Here, the potential difference between the potential of the surface of the developing roller 114 (developing potential Vd) and the potential of the electrostatic latent image formed on the surface of the photoreceptor drum 122 (residual potential Ver) is called the contrast voltage Vc. The contrast voltage is related to the density of toner that moves from the developing roller 114 to the electrostatic latent image on the photoreceptor drum 122. The density of the toner image formed on the photoreceptor drum 122 is adjusted by controlling the contrast voltage Vc. When adjusting the contrast voltage Vc, the developing potential Vd and the charging potential Vo are adjusted.

[0043] The image developed with toner on the surface of the photoconductor drum 122 (toner image) moves to a position corresponding to the primary transfer roller 128 as the photoconductor drum 122 rotates. The primary transfer roller 128 faces the photoconductor drum 122 with the intermediate transfer belt 21 in between. The primary transfer roller 128 contacts the surface of the photoconductor drum 122 with the intermediate transfer belt 21 in between. The primary transfer roller 128 transfers the toner image on the surface of the photoconductor drum 122 to the intermediate transfer belt 21 (primary transfer).

[0044] The photoconductor cleaner 130 is positioned downstream of the location where the toner image on the surface of the photoconductor drum 122 is transferred onto the intermediate transfer belt 21, in the circumferential direction of the photoconductor drum 122. The photoconductor cleaner 130 removes toner from the surface of the photoconductor drum 122. That is, the photoconductor cleaner 130 removes toner remaining on the surface of the photoconductor drum 122 after performing the primary transfer of the toner image from the photoconductor drum 122 to the intermediate transfer belt 21. The photoconductor cleaner 130 has, for example, a cleaning blade that is in close contact with the surface of the photoconductor drum 122. The photoconductor cleaner 130 removes toner from the surface of the photoconductor drum 122 as the cleaning blade rotates.

[0045] The static eliminator 132 is positioned downstream of the photoreceptor cleaner 130 in the circumferential direction of the photoreceptor drum 122. The static eliminator 132 irradiates light onto the surface of the photoreceptor drum 122. This allows the static eliminator 132 to remove any remaining charge from the photoreceptor layer 124 on the surface of the photoreceptor drum 122.

[0046] Next, the configuration of the control system in the digital multifunction printer 1, which is an image forming apparatus according to this embodiment, will be described. Figure 4 is a block diagram showing an example of the control system configuration in a digital multifunction printer 1, which is an image forming apparatus according to this embodiment. As shown in Figure 4, the system controller 5 includes a processor 101, ROM 102, RAM 103, storage device (storage unit) 104, and a communication interface (I / F) 105. Furthermore, the processor 101 of the system controller 5 is connected to various parts within the digital multifunction device 1 via various interfaces.

[0047] The processor 101 performs various processes by executing programs. The processor 101 is, for example, a CPU. The processor 101 is connected to ROM 102, RAM 103, storage device 104, and communication interface (I / F) 105, etc. The processor 101 is also connected to various parts of the printer 2, the operation panel 3, and the scanner 4 via the interface.

[0048] ROM102 is a non-rewritable, non-volatile memory. ROM102 operates as program memory for storing programs. RAM103 operates as working memory or buffer memory. The processor 101 performs various processes by executing programs stored in ROM102 or storage device 104 using RAM103.

[0049] The storage device 104 is a rewritable, non-volatile memory. For example, the storage device 104 is composed of a storage device such as an HDD (hard disk drive) or an SSD (solid state drive). The storage device 104 stores data such as control data, control programs, setting information, image data, and print job data. In this embodiment, the storage device 104 is an example of a storage unit that stores life setting values, which will be described later. The storage device 104 is also an example of a storage unit that stores notification setting values, which will be described later. Furthermore, the storage device 104 also stores a photoreceptor table, which will be described later.

[0050] The communication interface 105 is an interface for data communication with external devices. For example, the communication interface 105 communicates with user terminals such as PCs and mobile devices via a network. The communication interface 105 may also be used to receive input such as image printing requests (print jobs) from user terminals such as PCs.

[0051] As shown in Figure 4, the printer 2 has a power supply 140 in addition to the configurations shown in Figures 1 and 3. The power supply 140 supplies voltage to the developer 110, the charger 126, the primary transfer roller 128, and the secondary transfer roller 22, respectively. In the configuration example shown in Figure 4, the power supply 140 includes a high-voltage power supply 141, a developer bias transformer 142, a charge bias transformer 143, a primary transfer bias transformer 144, and a secondary transfer bias transformer 145. The developer bias transformer 142, the charge bias transformer 143, and the primary transfer bias transformer 144 are provided for each image forming station SY, SM, SC, and SK.

[0052] The high-voltage power supply 141 supplies high voltage to various transformers 142, 143, 144, and 145. High voltage refers to voltages ranging from several hundred volts to several kilovolts. The high-voltage power supply 141 generates high voltage from an input voltage of several tens of volts, for example.

[0053] The developing bias transformer 142 supplies the developing potential to the developing unit 110. The developing bias transformer 142 converts the high voltage generated by the high-voltage power supply 141 into a developing bias voltage of a voltage value set by the system controller 5. The developing bias transformer 142 supplies the developing bias voltage specified by the system controller 5 to the developing unit 110. As a result, the developing potential Vd of the developing unit 110 is controlled by the system controller 5.

[0054] The electrostatic bias transformer 143 supplies an electrostatic bias voltage to the charger 126. The electrostatic bias transformer 143 converts the high voltage generated by the high-voltage power supply 141 into an electrostatic bias voltage of a voltage value set by the system controller 5. The electrostatic bias transformer 143 supplies the electrostatic bias voltage specified by the system controller 5 to the charger 126. As a result, the charger 126 charges the photoreceptor layer 124 on the surface of the photoreceptor drum 122 to an electrostatic potential Vo corresponding to the electrostatic bias voltage specified by the system controller 5.

[0055] The primary transfer bias transformer 144 supplies the primary transfer bias voltage to the primary transfer roller 128. The primary transfer bias transformer 144 converts the high voltage generated by the high-voltage power supply 141 into a primary transfer bias voltage of a voltage value set by the system controller 5. The primary transfer bias transformer 144 supplies the primary transfer bias voltage specified by the system controller 5 to the primary transfer roller 128.

[0056] The secondary transfer bias transformer 145 supplies a secondary transfer bias voltage to the secondary transfer roller 22. The secondary transfer bias transformer 145 converts the high voltage generated by the high-voltage power supply 141 into a secondary transfer bias voltage of a voltage value set by the system controller 5. The secondary transfer bias transformer 145 supplies a secondary transfer bias voltage of a value specified by the system controller 5 to the secondary transfer roller 22.

[0057] Next, the operation of the image forming process in the printer 2, which is an image forming apparatus according to this embodiment, will be described. The digital multifunction device 1 acquires an image to be formed on the recording medium M and performs image formation processing to print the acquired image onto the recording medium M using the printer 2. For example, when a copy is instructed on the control panel 3, the processor 101 of the system controller 5 executes the process of printing the image of the original document scanned by the scanner 4 onto the recording medium M using the printer 2.

[0058] When the system controller 5's processor 101 performs image formation processing, it takes in the recording medium M stored in the storage compartment via the media supply mechanism 13. The processor 101 then uses the transport mechanism 15 to transport the recording medium M supplied from the media supply mechanism 13 to the front of the registration roller 56 in the printer 2.

[0059] Furthermore, the processor 101 of the system controller 5 generates images to be formed by each image forming station SY, SM, SC, and SK based on the image to be printed on the recording medium M (print image). For example, the processor 101 generates images of each color (yellow, magenta, cyan, and black) to be formed by each image forming station SY, SM, SC, and SK from the print image. Once the processor 101 has generated images of each color from the print image, it causes each image forming station to form the generated images of each color.

[0060] In each image forming station SY, SM, SC, and SK, the charger 126 receives a charging bias voltage from the charging bias transformer 143 to charge the photoreceptor layer 124 of the photoreceptor drum 122. The exposure unit 100 irradiates the photoreceptor drum 122 of each image forming station SY, SM, SC, and SK with light that forms an electrostatic latent image corresponding to the image of each color. In each image forming station SY, SM, SC, and SK, an electrostatic latent image is formed on the photoreceptor layer 124 of the photoreceptor drum 122 by the light irradiated from the exposure unit 100.

[0061] Each image forming station SY, SM, SC, and SK develops the electrostatic latent image on the photoreceptor drum 122 using the toner of the respective color contained in the developer unit 110. In each image forming station SY, SM, SC, and SK, the developing roller 114 rotates while carrying the developer containing the respective color toner supplied from the developer container 112. The developing roller 114, which carries the developer, has a developing bias voltage applied to it from the developing bias transformer 142. The developer unit 110 supplies the toner in the developer carried by the developing roller 114 to the electrostatic latent image based on the potential difference (contrast voltage) between the potential on the developing roller 114 and the electrostatic latent image on the photoreceptor drum 122.

[0062] In each image forming station SY, SM, SC, and SK, the photoreceptor drum 122 moves the image (toner image) developed by the developer 110 to a position facing the primary transfer roller 128 (primary transfer position). At the primary transfer position, the photoreceptor drum 122 faces the primary transfer roller 128 across the intermediate transfer belt 21. A primary transfer bias voltage from the primary transfer bias transformer 144 is applied to the primary transfer roller 128. The toner image on the photoreceptor drum 122 is transferred to the intermediate transfer belt 21 by the primary transfer roller to which the primary transfer bias voltage is applied at the primary transfer position. When forming a color image, each image forming station SY, SM, SC, and SK transfers the toner images of each color on the intermediate transfer belt 21 in a superimposed manner. As a result, a color image formed by superimposing the toner images of each color is transferred onto the intermediate transfer belt 21.

[0063] The intermediate transfer belt 21 moves the transferred toner image to a position opposite the secondary transfer roller 22 (secondary transfer position). The registration roller 56 feeds the recording medium M to the secondary transfer position in sync with the position and timing of the image transferred on the intermediate transfer belt 21. As a result, the secondary transfer roller 22 and the support roller 23 transport the recording medium M while sandwiching the overlapping intermediate transfer belt 21 and the recording medium M at the secondary transfer position. A secondary transfer bias voltage from the secondary transfer bias transformer 145 is applied to the secondary transfer roller 22. The toner image on the intermediate transfer belt 21 is transferred to the recording medium M by the secondary transfer roller 22, to which the secondary transfer bias voltage is applied at the secondary transfer position.

[0064] The recording medium M, having passed through the secondary transfer position, is transported to the fuser unit 26. The fuser unit 26 fixes the toner image transferred from the intermediate transfer belt 21 to the recording medium M at the secondary transfer position. The fuser unit 26 applies heat and pressure to the recording medium M on which the toner image has been transferred, fixing the toner image to the recording medium M. The recording medium M, having passed through the fuser unit 26, is discharged from the paper discharge section with the toner image fixed.

[0065] Next, the lifespan (replacement time) of the photoreceptor drum 122 in the printer 2 of the digital multifunction device, which is an image forming apparatus 1 according to this embodiment, will be described. As described above, the photoreceptor drum 122 has a photoreceptor layer 124 on its surface. After the toner image is transferred to the transfer member, the surface of the photoreceptor drum 122 is cleaned by the cleaning blade of the photoreceptor cleaner. As the photoreceptor drum 122 rotates with the cleaning blade in contact with its surface, the photoreceptor layer 124 on the surface is scraped. Scraping of the photoreceptor layer 124 is one of the main causes of deterioration of the photoreceptor drum 122. As the scraping of the photoreceptor layer 124 progresses, the residual potential of the photoreceptor layer 124 of the photoreceptor drum 122 increases.

[0066] The photoreceptor drum 122 has a set lifespan (replacement time) that corresponds to the degree of deterioration of the photoreceptor drum 122 due to factors such as film abrasion of the photoreceptor layer 124. Generally, indicators (deterioration indicators, life indicators) used to determine the lifespan of the photoreceptor drum 122 due to deterioration include the number of sheets of paper fed (number of prints), the driving distance of the photoreceptor drum, or the driving time. The image forming apparatus 1 determines that the photoreceptor drum 122 has reached the end of its lifespan (replacement time) when a specific deterioration index reaches the life setting value.

[0067] The deterioration of the photoconductor drum 122, specifically the abrasion of the photoconductor layer 124, is affected by the environment. Therefore, a pre-set fixed life setting (initial value of the life setting) may not be suitable for determining the actual lifespan of the photoconductor drum 122. For example, in a low-temperature environment, the cleaning blade pressed against the surface of the photoconductor drum 122 may harden, accelerating the abrasion of the photoconductor layer 124. If the abrasion of the photoconductor layer 124 is accelerated, the photoconductor drum 122 needs to be replaced early, before reaching the fixed life setting, in order to maintain the desired image quality. In other words, since the degree of deterioration of the photoconductor drum 122 varies depending on the actual usage environment, it is necessary to determine its lifespan according to its actual condition.

[0068] In this embodiment, the image forming apparatus 1 corrects (updates) the life setting value for the degradation index according to the degree of degradation of the photoreceptor drum 122. The image forming apparatus 1 also calculates the degree of degradation of the photoreceptor drum 122 based on the residual potential of the photoreceptor layer 124 on the surface of the photoreceptor drum 122. The residual potential of the photoreceptor drum 122 may be measured by providing a potential sensor, or it may be calculated by an image adjustment operation (image quality maintenance control). In this embodiment, the image forming apparatus 1 will be described as calculating the current residual potential (actual residual potential) of the photoreceptor layer 124 of the photoreceptor drum 122 by an image adjustment operation.

[0069] The image adjustment operation in the image forming apparatus 1 is a process of adjusting the density of the image formed (transferred) onto the recording medium M. The density of the image formed on the recording medium M changes depending on the amount (density) of toner supplied to the electrostatic latent image from the developing roller 114 when developing the electrostatic latent image on the photoreceptor drum 122. In other words, the image adjustment operation by the image forming apparatus 1 is a process of adjusting the amount of toner supplied to the electrostatic latent image. In the image adjustment operation, the toner density is adjusted by adjusting the contrast voltage.

[0070] Figures 5(a) and (b) show the relationships between the various potentials during the image adjustment operation by the image forming apparatus 1. The examples shown in Figures 5(a) and (b) illustrate the relationship between the charging potential Vo, residual potential Ver, development potential Vd, contrast voltage Vc, and background voltage Vbg. The charging potential Vo is the surface potential of the photoreceptor drum 122 charged by the charger 126. The residual potential Ver is the potential of the electrostatic latent image portion on the surface of the photoreceptor drum 122 irradiated with light from the exposure unit 100. The developing potential Vd is the potential at which the developing unit 110 supplies toner to the electrostatic latent image on the photoreceptor drum 122. The contrast voltage Vc is the potential difference between the developing potential Vd and the residual potential Ver. The background voltage Vbg is the potential difference between the charging potential Vo and the developing potential Vd.

[0071] The toner density (image density) is adjusted by the contrast voltage Vc, which is the potential difference between the residual potential Ver, which is the potential of the electrostatic latent image in the photoreceptor drum 122, and the development potential Vd. The image forming apparatus 1 performs an image adjustment operation (image quality maintenance control) to adjust the density of each color image formed by each image forming station. The image forming apparatus 1 may perform the image adjustment operation to adjust the toner density at a predetermined timing (predetermined cycle), or at any arbitrary timing.

[0072] The image forming apparatus 1 adjusts the density of each color image formed on the recording medium M by controlling the contrast voltage Vc at each color image forming station. During the image adjustment operation, the image forming apparatus 1 adjusts the contrast voltage Vc at each image forming station and calculates the current residual potential Ver based on the contrast voltage Vc. In addition, the image forming apparatus 1 also adjusts the background voltage Vbg in accordance with the adjustment of the contrast voltage Vc to prevent toner overprinting.

[0073] For example, during image adjustment, the image forming apparatus 1 determines the density of the images (toner images) formed by each image forming station SY, SM, SC, and SK detected by the toner sensor 24. If the image forming apparatus 1 determines that the density of a certain image is low, it increases the contrast voltage Vc at the image forming station that formed that image, as shown in Figure 5(b). When increasing the contrast voltage Vc, the image forming apparatus 1 also adjusts the background voltage Vbg by increasing the charge potential Vo, as shown in Figure 5(b). In this way, the image forming apparatus 1 adjusts the density of the images formed by each image forming station so that it falls within a predetermined range.

[0074] Next, we will explain the relationship between the degradation index, which is an indicator of the degradation of the photoreceptor drum 122 in the image forming apparatus 1, and the residual potential Ver of the photoreceptor drum 122. Figure 6 shows an example of the residual potential Ver of the photoreceptor drum 122 with respect to the degradation index in the image forming apparatus 1. Here, the degradation index includes the number of sheets of paper fed (number of prints), the driving distance of the photoconductor drum, and the driving time of the photoconductor drum. Figure 6 shows that the residual potential Ver increases as the number of sheets of paper fed, driving distance, and driving time, which are degradation indices, increase. When the residual potential Ver reaches a predetermined threshold (limit value) VT, the photoconductor drum 122 is determined to have reached the end of its lifespan (time for replacement). The setting value (life setting value) for determining the lifespan of the photoconductor drum 122 is set relative to the degradation index. For example, when setting the life setting value based on the graph shown in Figure 6, the degradation index at which the residual potential Ver reaches the limit value VT is set as the life setting value.

[0075] Next, we will explain the change in residual potential (residual charge value) Ver with respect to the degradation index of the photoreceptor drum 122 in the image forming apparatus 1. Figure 7 shows an example of the change in residual potential Ver against the degradation index of the photoreceptor drum 122 in the image forming apparatus 1. In the example shown in Figure 7, the progression of the pre-set (assumed) residual potential (hereinafter also referred to as the standard residual potential) Ver(a) is shown by a solid line, and the progression of the actually calculated (or measured) residual potential (hereinafter also referred to as the actual residual potential) Ver(b) is shown by a dotted line. For example, the standard residual potential Ver(a) is calculated by a photoreceptor table that stores residual potentials pre-set taking into account environmental conditions. The actual residual potential Ver(b) is calculated as an RMS value by the image adjustment operation. However, the actual residual potential Ver(b) can be the actual residual potential of the photoreceptor drum 122, or it can be a value measured by a potential sensor or the like.

[0076] Figure 7 illustrates a case where the actual residual potential Ver(b) is greater than the standard residual potential Ver(a) for a given degradation index. This indicates that the actual degradation of the photoreceptor drum 122 progresses faster than the pre-set degradation (standard degradation). In the standard residual potential progression, the lifespan (standard lifespan) is reached when the residual potential Ver(a) reaches a predetermined limit value VT. In contrast, in the actual residual potential progression, the lifespan (predicted lifespan) is reached earlier than the standard lifespan when the residual potential Ver(b) reaches a predetermined limit value VT.

[0077] Furthermore, if the degradation index is the number of sheets passed through P, then the actual residual potential Ver(bPi) when the number of sheets passed through Pi will be greater than the standard residual potential Ver(aPi). Also, if the degradation index is the operating time Ti of the photoreceptor drum 122, then the actual residual potential Ver(bTi) when the operating time Ti will be greater than the standard residual potential Ver(aTi).

[0078] Next, the degradation determination process of the photoreceptor drum 122 in the image forming apparatus 1 according to the embodiment will be described. Figure 8 is a flowchart illustrating an example of operation in the image forming apparatus 1 according to this embodiment, including a degradation determination process for determining whether the photoreceptor drum 122 has reached the end of its lifespan. Here, the degradation determination process shown in Figure 8 is performed when the degradation indicator (number of sheets fed, driving distance, driving time, etc.) has not reached a predetermined life setting value. The image forming apparatus 1 may calculate the degradation index at any time. For example, the timing of calculating the degradation index may be for each print job, when an image adjustment operation (image quality maintenance control) is performed, or synchronized with the timing of power on or off or sleep recovery.

[0079] The processor 101 of the system controller 5 of the image forming apparatus 1 performs an image adjustment operation, including the calculation of residual potential, at a predetermined timing set in advance (ACT 11). The processor 101 may also perform the image adjustment operation in response to an operation instruction from the operator.

[0080] However, the degradation detection process does not need to be performed after every image adjustment operation; the timing for performing the degradation detection process in conjunction with the image adjustment operation can be set. For example, the image adjustment operation could be performed daily, and the degradation detection process associated with the image adjustment operation could be set to be performed every three days.

[0081] When the image forming apparatus 1's processor 101 performs degradation determination processing, it acquires the current actual residual potential Ver(b) of the photoreceptor drum 122, which is calculated by the image adjustment operation (ACT12). Upon acquiring the current actual residual potential Ver(b), the processor 101 converts the acquired actual residual potential Ver(b) to the actual residual potential Ver(b)', which is the value at a predetermined applied voltage (ACT13). Here, the applied voltage is the charge bias voltage supplied by the charge bias transformer 143 to the charger 126. The system controller 5's processor 101 controls the charge bias voltage in accordance with the adjustment of the contrast voltage during the image adjustment operation. For this reason, the processor 101 converts the actual residual potential Ver(b) calculated during the image adjustment operation to the actual residual potential Ver(b)' at a predetermined applied voltage (for example, 600V).

[0082] Also, the processor 101 of the image forming apparatus 1 acquires a standard residual potential Ver(a)' corresponding to the current degradation index based on the value stored in the previously set photoreceptor table (ACT14). For example, the photoreceptor table stores values indicating the relationship between the applied voltage, charging potential, and residual potential in consideration of environmental conditions. The photoreceptor table is stored in the ROM 102 or the storage device 104 in the system controller 5. The processor 101 calculates the standard residual potential Ver(a) for the current degradation index as the standard residual potential Ver(a)' at a predetermined applied voltage based on the photoreceptor table.

[0083] When the processor 101 of the image forming apparatus 1 acquires the current actual residual potential Ver(b)' and the standard residual potential Ver(a)', it determines whether the degradation has progressed more than the assumption (standard) (ACT15). For example, the processor 101 determines whether the degradation of the photoreceptor drum 122 has progressed earlier than the assumption based on the difference between the current actual residual potential Ver(b)' and the standard residual potential Ver(a)'.

[0084] Specifically, if Ver(b)'>Ver(a)', the processor 101 determines that the degradation of the photoreceptor drum 122 has progressed earlier than the assumption. Also, since the actual residual potential Ver(b)' is a value actually calculated, there may be errors and the like. For this reason, the processor 101 may be configured to determine that the degradation of the photoreceptor drum 122 has progressed earlier than the assumption if Ver(b)'-Ver(a)' is equal to or greater than a predetermined value. Further, if Ver(b)'<Ver(a)', the processor 101 may be configured to determine that the progress of the degradation of the photoreceptor drum 122 is slower than the assumption.

[0085] If the processor 101 of the image forming apparatus 1 determines that degradation is progressing (ACT15, YES), it determines whether the current actual residual potential Ver(b)' has reached the limit value VT (ACT16). If the processor 101 of the image forming apparatus 1 has not reached the limit value VT (ACT16, NO), it continues normal operation (ACT17).

[0086] If the current actual residual potential Ver(b)' reaches the limit value VT (ACT16, YES), the processor 101 of the image forming apparatus 1 performs a lifespan termination process (ACT18) assuming that the photoreceptor drum 122 has reached the end of its lifespan. As part of the lifespan termination process, the processor 101 notifies that the photoreceptor drum 122 has reached the end of its lifespan (time for replacement).

[0087] For example, the processor 101 displays a message on the display unit of the control panel 3 prompting the user to replace the photoreceptor drum. This informs the user that the photoreceptor drum 122 has reached the end of its lifespan. The processor 101 also notifies the server device 300 via the communication interface 105 that the photoreceptor drum 122 of the image forming apparatus 1 has reached the end of its lifespan. This informs administrators, service personnel, etc., that the photoreceptor drum 122 of the image forming apparatus 1 has reached the end of its lifespan.

[0088] Furthermore, the processor 101 may also perform control settings as a lifespan termination process, which involves executing control actions when the photoreceptor drum 122 reaches the end of its lifespan. This allows the processor 101 to continue processing such as printing by controlling the state of the photoreceptor drum 122, even when the photoreceptor drum 122 has reached the end of its lifespan.

[0089] According to the degradation determination process described above, the image forming apparatus according to the embodiment can determine the lifespan of the photoreceptor drum based on the actual residual potential of the photoreceptor drum, in accordance with the actual state of the photoreceptor drum. That is, if the actual residual potential calculated by the image adjustment operation is higher than the standard residual potential, the image forming apparatus determines whether the actual residual potential has reached a limit value. The image forming apparatus considers the photoreceptor drum to have reached the end of its lifespan if the actual residual potential has reached a limit value.

[0090] This allows the image forming apparatus to determine whether the photoreceptor drum has reached the end of its lifespan based on its actual condition, even before it reaches the default set lifespan (standard set lifespan) assigned to the degradation index. As a result, if the image forming apparatus determines that the photoreceptor drum has reached the end of its lifespan, even before the degradation index reaches the standard set lifespan, it can provide guidance prompting the replacement of the photoreceptor drum.

[0091] Next, an example of an operation including a correction process for correcting the life setting value for determining the life of the photoreceptor drum 122 in the image forming apparatus 1 according to the embodiment will be described. Figure 9 is a flowchart illustrating an example of operation in the image forming apparatus 1 according to the embodiment, including a correction process for correcting the life setting value that determines the lifespan of the photoreceptor drum 122. Here, the image forming apparatus 1 calculates the current actual residual potential (actual residual potential) through an image adjustment operation. That is, the processor 101 of the system controller 5 of the image forming apparatus 1 performs an image adjustment operation, including the calculation of the residual potential, according to a predetermined timing or execution instruction (ACT31).

[0092] The processor 101 of the image forming apparatus 1 acquires the current actual residual potential Ver(b) of the photoreceptor drum 122, which is calculated by the image adjustment operation (ACT32). Once the processor 101 acquires the current actual residual potential Ver(b), it converts the acquired actual residual potential Ver(b) to the actual residual potential Ver(b)', which is the value at a predetermined applied voltage (ACT33).

[0093] Furthermore, the processor 101 obtains the standard residual potential Ver(a)' at a predetermined applied voltage corresponding to the current degradation index based on the values ​​stored in the pre-set photoreceptor table (ACT34).

[0094] The processor 101 of the image forming apparatus 1 obtains the current actual residual potential Ver(b)' and the standard residual potential Ver(a)', and then calculates the degree of deterioration D, which indicates the progress of deterioration of the photoreceptor drum 122 (ACT35). Here, the processor 101 calculates the degree of deterioration D, which indicates the progress of deterioration of the photoreceptor drum 122, based on the standard residual potential. For example, the processor 101 calculates the degree of deterioration D based on the degree of change in the actual residual potential (current value - past value) and the corresponding degree of change in the standard residual potential.

[0095] Here, as the first specific example, we will explain a method for calculating the degree of degradation D using the difference between the current actual residual potential and the previous actual residual potential. As a first specific example, the processor 101 of the image forming apparatus 1 can calculate the degree of degradation D when the degradation index is the number of sheets passed through P by the following calculation. Number of sheets of paper used to calculate the actual residual potential at this time (currently): Pi Number of sheets of paper used when the actual residual potential was calculated last time (in the past): Pi-1 Standard residual potential at paper feed count Pi (at predetermined applied voltage): Ver(aPi)' Actual residual potential at paper count Pi (at predetermined applied voltage): Ver(bPi)' Standard residual potential at paper feed count Pi-1 (at predetermined applied voltage): Ver(aPi-1)' Actual residual potential at paper count Pi-1 (at predetermined applied voltage): Ver(bPi-1)' Deterioration degree D=[Ver(bPi)'-Ver(bPi-1)'] / [Ver(aPi)-Ver(aPi-1)'].

[0096] As a first specific example, the processor 101 of the image forming apparatus 1 can calculate the degree of degradation D when the degradation index is the driving time (driving counter indicating the driving time) T of the photoreceptor drum 122 by the following calculation. The operating time used to calculate the actual residual potential at this time (currently): Ti Operating time when the previous (past) actual residual potential was calculated: Ti-1 Standard residual potential at operating time Ti (at a predetermined applied voltage): Ver(aTi)' Actual residual potential at operating time Ti (at predetermined applied voltage): Ver(bTi)' Standard residual potential at operating time Ti-1 (at predetermined applied voltage): Ver(aTi-1)' Actual residual potential at operating time Ti-1 (at predetermined applied voltage): Ver(bTi-1)' Deterioration degree D=[Ver(bTi)'-Ver(bTi-1)'] / [Ver(aTi)-Ver(aTi-1)'].

[0097] Furthermore, in the example described above, the degree of degradation D was calculated using the difference between the current residual potential and the previous residual potential. However, the degree of degradation D is not limited to being calculated from the difference with the previous residual potential. The degree of degradation D described above can be calculated using the difference between the current residual potential and past residual potentials. For example, when the photoreceptor drum 122 is set, the processor 101 stores the residual potential calculated in the setup process as the initial value of the residual potential in the storage device 104. After the setup process, the processor 101 may also calculate the degree of degradation D using the difference between the current actual residual potential obtained in the image adjustment operation and the initial value of the residual potential.

[0098] Here, as a second specific example, we will explain a method for calculating the degree of degradation D using the difference between the current residual potential and the initial residual potential. As a second specific example, the processor 101 of the image forming apparatus 1 can calculate the degree of degradation D when the degradation index is the number of sheets passed P by the following calculation. Number of sheets of paper used to calculate the actual residual potential at this time (currently): Pi Standard residual potential at paper feed count Pi (at predetermined applied voltage): Ver(aPi)' Actual residual potential at paper count Pi (at predetermined applied voltage): Ver(bPi)' Standard residual potential at the initial paper count P0 (at a predetermined applied voltage): Ver(0)' Deterioration degree D=[Ver(bPi)'-Ver(0)'] / [Ver(aPi)-Ver(0)'].

[0099] As a second specific example, the processor 101 of the image forming apparatus 1 can calculate the degree of degradation D when the degradation index is the driving time T of the photoreceptor drum 122 by the following calculation. The operating time used to calculate the actual residual potential at this time (currently): Ti Standard residual potential at operating time Ti (at a predetermined applied voltage): Ver(aTi)' Actual residual potential at operating time Ti (at predetermined applied voltage): Ver(bTi)' Standard residual potential at the initial operating time T0 (at a predetermined applied voltage): Ver(0)' Deterioration degree D=[Ver(bTi)'-Ver(0)'] / [Ver(aTi)-Ver(0)'].

[0100] The processor 101 of the image forming apparatus 1 calculates the degree of degradation D and corrects the life setting value based on the calculated degree of degradation D (ACT36). The life setting value is a value set assuming a value corresponding to the degradation index when the photoreceptor drum 122 reaches the end of its lifespan. For example, in the initial state (standard state), the life setting value is the degradation index when the standard residual potential reaches the limit value VT. The degree of degradation D is a value that indicates the degree of degradation progression in the photoreceptor drum 122 relative to the standard state. Therefore, by correcting the life setting value with the degree of degradation D, a life setting value indicating the current lifespan of the photoreceptor drum 122 can be obtained.

[0101] Figure 10 shows an example of a life curve L representing the standard life setting and a corrected life curve Li corrected for the degree of degradation D. In the example shown in Figure 10, the corrected life curve Li represents the corrected life when the degradation of the photoreceptor drum 122 progresses faster than the standard. When the degradation of the photoreceptor drum 122 progresses faster than the standard, the degradation degree D becomes a value that corrects the life of the photoreceptor drum 122 to be shorter than the standard life. In other words, if the degradation index of the corrected life curve Li is the number of sheets of paper passed through (corrected life) until the residual potential reaches a predetermined limit value VT is fewer sheets of paper passed through (corrected life) than the standard life obtained from the standard life curve L. Also, if the degradation index of the corrected life curve Li is the operating time, the operating time until the residual potential reaches a predetermined limit value VT (corrected life) is shorter than the standard life.

[0102] Here, we will explain a specific example of how the image forming apparatus 1 corrects the life setting value using the degradation level D. The processor 101 of the image forming apparatus 1 can calculate a corrected value for the life setting value (corrected life setting value) using the degree of deterioration D when the deterioration index is the number of sheets passed P, by the following calculation. Standard life setting value for the number of sheets fed: LPu Corrected life setting value for the number of sheets passed: LPui = LPu / D.

[0103] Furthermore, if the degradation index is the driving time T of the photoreceptor drum 122, the processor 101 of the image forming apparatus 1 can calculate a corrected value of the life setting value (corrected life setting value) using the degradation degree D by the following calculation. Standard life setting value for operating time: LTu Corrected life setting value for operating time: LTui = LTu / D.

[0104] The processor 101 of the image forming apparatus 1 corrects the life setting value based on the degradation level D, and then determines whether the photoreceptor drum 122 has reached the end of its life based on the corrected life setting value (ACT37). The processor 101 of the image forming apparatus 1 determines whether the photoreceptor drum 122 has reached the end of its life based on whether the degradation index is equal to or greater than the corrected life setting value. If the photoreceptor drum 122 has not reached the end of its life based on the corrected life setting value (ACT37, NO), the processor 101 continues normal operation (ACT38).

[0105] The processor 101 of the image forming apparatus 1 executes a lifespan termination process (ACT39) if the photoreceptor drum 122 has reached the end of its lifespan according to the corrected life setting value (ACT37, YES). As part of the lifespan termination process, the processor 101 notifies that the photoreceptor drum 122 has reached the end of its lifespan (time for replacement).

[0106] For example, the processor 101 displays a message on the display unit of the operation panel 3 prompting the replacement of the photoreceptor drum. The processor 101 also notifies the server device 300 via the communication interface 105 that the photoreceptor drum 122 of the image forming apparatus 1 has reached the end of its lifespan. Furthermore, the processor 101 may perform control settings as part of the lifespan processing to execute control actions corresponding to when the photoreceptor drum 122 reaches the end of its lifespan.

[0107] According to the above correction process, the image forming apparatus according to the embodiment corrects the life setting value for determining the life of the photoreceptor drum based on the actual residual potential in the photoreceptor drum. That is, the image forming apparatus corrects the standard life setting value based on the degree of change in the actual residual potential, which is actually calculated in the image adjustment operation with respect to the standard residual potential. Specifically, the image forming apparatus corrects the life setting value based on the degree of deterioration calculated from the degree of change in the actual residual potential, which is actually calculated in the image adjustment operation (the difference between the current actual residual potential and the past residual potential) and the degree of change in the standard residual potential (the difference between the current standard residual potential and the past standard residual potential).

[0108] This allows the image forming apparatus to correct the default set life (standard set life) assigned to the degradation index according to the actual degree of degradation in the photoreceptor drum. In other words, by feeding back the actual degree of degradation of the photoreceptor drum to the life setting value, the image forming apparatus can determine whether the life appropriate to the actual condition of the photoreceptor drum has been reached. As a result, even if the degradation index has not yet reached the standard set life, the image forming apparatus can detect that the life appropriate to the actual condition has been reached and can provide guidance such as prompting the replacement of the photoreceptor drum.

[0109] Next, an example of operation in the image forming apparatus 1 according to the embodiment, including a pre-notification process in response to the predicted end of life of the photoreceptor drum 122, will be described. Figure 11 is a flowchart illustrating an example of operation in the image forming apparatus 1 according to the embodiment, including a pre-notification process based on the predicted end of life of the photoreceptor drum 122. The pre-notification process shown in Figure 11 can be performed at any time. For example, the pre-notification process may be performed at predetermined intervals (daily, weekly), or it may be performed when the life setting value is corrected by the process described above.

[0110] When the image forming apparatus 1's processor 101 performs a pre-notification process, it calculates a value for the degradation index until the end of its life (a degradation index corresponding to the life setting value) (ACT51). For example, if the degradation index is the number of sheets of paper passed through, the processor 101 calculates a value by subtracting the current number of sheets of paper passed through from the number of sheets of paper passed through set as the life setting value (the number of sheets of paper passed through when the residual potential reaches its limit). Specifically, the number of sheets of paper passed through until the end of its life is "LPui-Pi", which is the corrected life setting value (LPui) minus the current number of sheets of paper passed through (Pi).

[0111] The processor 101 calculates the value of the degradation index until the end of its lifespan, and then calculates the number of days remaining until the end of its lifespan (ACT52). For example, if the degradation index is the number of sheets of paper passed through, the number of days remaining until the end of its lifespan H can be calculated by dividing the number of sheets of paper passed through until the end of its lifespan (LPui-Pi) by the number of sheets of paper passed through in one day (predicted value).

[0112] As a specific example, let's assume that the image forming apparatus 1 can determine the average number of sheets (prints) per month (MDL) and the number of operating days per month. In this case, the number of months remaining until the end of its lifespan can be calculated by dividing the number of sheets (LPui-Pi) remaining until the end of its lifespan by the average number of sheets (MDL) per month. Therefore, the number of days remaining until the end of its lifespan may also be calculated using the following formula. The number of days remaining until the end of the life cycle is reached is H = (LPui - Pi) / [MDV / (number of working days per month)].

[0113] The processor 101 calculates the number of days H remaining until the end of its lifespan and compares this number with the notification setting value K remaining (ACT53). If the number of days H remaining until the end of its lifespan is greater than the notification setting value K remaining (ACT54, YES), the processor 101 continues to operate without issuing a prior notification (ACT55). If the number of days H remaining until the end of its lifespan is less than or equal to the notification setting value K remaining (ACT54, YES), the processor 101 issues a prior notification regarding the number of days remaining until the end of its lifespan, etc. (ACT56).

[0114] Through the above pre-notification process, the image forming apparatus can predict the time until the photoreceptor drum reaches the end of its lifespan using a life setting value corrected according to the actual deterioration state. Furthermore, the image forming apparatus can notify the user or administrator of the end of the lifespan of the photoreceptor drum before the drum actually reaches the end of its lifespan.

[0115] As described above, the image forming apparatus according to the embodiment can determine the lifespan of the photoreceptor drum according to its deterioration state without adding a detection device for determining the lifespan of the photoreceptor drum. Furthermore, even if the lifespan of the photoreceptor drum becomes shorter than the standard set lifespan due to deterioration progressing beyond expectations, the image forming apparatus according to the embodiment can properly notify the user that the photoreceptor drum has reached the end of its lifespan.

[0116] As a result, the image forming apparatus according to this embodiment can prevent malfunctions of the main body of the image forming apparatus caused by prolonged use of a photoreceptor drum that has reached the end of its lifespan. Furthermore, the image forming apparatus according to this embodiment can prompt the replacement of the photoreceptor drum at an appropriate time. In addition, since the image forming apparatus according to this embodiment can correct the standard set lifespan according to the actual condition of the photoreceptor drum, it is possible to use the life setting value for a longer period if the deterioration progresses more slowly than the standard.

[0117] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0118] As described above, the following image forming apparatus and storage medium can be implemented according to the detailed embodiments. [1] A photoreceptor in which an electrostatic latent image is formed by light irradiated onto a uniformly charged surface, A developing unit for developing the electrostatic latent image formed on the photoreceptor, A memory unit that stores a life setting value for determining when the photoreceptor has reached the end of its lifespan, A processor that corrects the life setting value stored in the memory unit according to the actual residual potential in the photoreceptor, An image forming apparatus having [2] The processor corrects the life setting value stored in the memory unit according to the actual residual potential and the standard residual potential in the photoreceptor. [1] The image forming apparatus described above. [3] The processor corrects the life setting value according to the degree of degradation calculated from the actual residual potential and the standard residual potential of the photoreceptor. [2] The image forming apparatus described above. [4] The processor calculates the degree of degradation based on a first difference between the current actual residual potential and the actual residual potential at a past time, and a second difference between the current standard residual potential and the standard residual potential at the past time. [3] The image forming apparatus described above. [5] The processor calculates the ratio of the first difference to the second difference as the degree of degradation, and corrects the life setting value according to the ratio. [4] The image forming apparatus described above. As correction of the life setting value stored in the memory unit [6] The processor calculates the degree of degradation based on a first difference between the current actual residual potential and the initial value of the residual potential, and a second difference between the current standard residual potential and the initial value of the residual potential. [3] The image forming apparatus described above. [7] The processor calculates the ratio of the first difference to the second difference as the degree of degradation, and corrects the life setting value according to the ratio. The image forming apparatus described in [6]. [8] When the life setting value is corrected, the processor notifies the number of days remaining until the photoreceptor reaches the end of its life, calculated based on the corrected life setting value. [1] The image forming apparatus described above. [9] The memory unit further stores a notification setting value, which includes a setting for the number of days remaining to notify in advance of the lifespan of the photoreceptor. The processor notifies the number of days remaining until the photoreceptor reaches the end of its lifespan when the number of days remaining until the photoreceptor reaches the number of days remaining according to the notification setting. [1] The image forming apparatus described above.

[10] A processor that controls an image forming apparatus having a photoreceptor on which an electrostatic latent image is formed and a developer for developing the electrostatic latent image, The current residual potential in the aforementioned photoreceptor is obtained as the actual residual potential. The residual potential calculated from the photoreceptor coefficient of the aforementioned photoreceptor is obtained as the standard residual potential. The memory unit corrects the life setting value for the photoreceptor stored in accordance with the actual residual potential and the standard residual potential. A storage medium that stores a program to execute a task. [Explanation of symbols]

[0119] 1...Digital multifunction device (image forming apparatus), 2...Printer, 3...Operation panel, 4...Scanner, 5...System controller, 21...Intermediate transfer belt (medium), 22...Secondary transfer roller, 24...Toner sensor, 100...Explorer, 101...Processor, 104...Storage device (storage unit), 105...Communication interface, 110...Developer, 112...Developer container, 114...Developer roller, 120...Toner density sensor, 122...Photoreceptor drum, 124...Photoreceptor layer, 126...Charger, 128...Primary transfer roller, 142...Developer bias transformer, 143...Charging bias transformer.

Claims

1. A photoreceptor in which an electrostatic latent image is formed by light irradiated onto a uniformly charged surface, A developing unit for developing the electrostatic latent image formed on the photoreceptor, A memory unit that stores a life setting value for determining when the photoreceptor has reached the end of its lifespan, A processor that corrects the life setting value stored in the memory unit according to the actual residual potential and the standard residual potential of the photoreceptor, An image forming apparatus having

2. The processor corrects the life setting value according to the degree of degradation calculated from the actual residual potential and the standard residual potential of the photoreceptor. The image forming apparatus according to claim 1.

3. The processor calculates the degree of degradation based on a first difference between the current actual residual potential and the actual residual potential at a past time, and a second difference between the current standard residual potential and the standard residual potential at the past time. The image forming apparatus according to claim 2.

4. The processor calculates the degree of degradation based on a first difference between the current actual residual potential and the initial value of the residual potential, and a second difference between the current standard residual potential and the initial value of the residual potential. The image forming apparatus according to claim 2.

5. The processor calculates the ratio of the first difference to the second difference as the degree of degradation, and corrects the life setting value according to the ratio. The image forming apparatus according to any one of claims 3 or 4.

6. A processor that controls an image forming apparatus having a photoreceptor on which an electrostatic latent image is formed and a developer for developing the electrostatic latent image, The current residual potential in the aforementioned photoreceptor is obtained as the actual residual potential. The residual potential calculated from the photoreceptor coefficient of the aforementioned photoreceptor is obtained as the standard residual potential. The memory unit corrects the life setting value for the photoreceptor stored in accordance with the actual residual potential and the standard residual potential. A program that performs an action.

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