Image forming apparatus

Abstract

This invention provides a technology for determining the lifespan of an electrostatic roller and replacing it at an appropriate time in an image forming apparatus that performs contact charging using an electrostatic roller. [Solution] The developing apparatus includes a rotatable image carrier, a rotatable charging roller that contacts the image carrier and forms a charging portion, and charges the surface of the image carrier with the charging portion, and a storage portion that contains a developer with an external additive added to its surface, and supplies the developer contained in the storage portion to the surface of the image carrier that has been charged by the charging roller, a drive unit that rotates the image carrier and the charging roller, an acquisition unit that acquires first information regarding the usage history of the charging roller and second information regarding the usage history of the developing apparatus, a memory that stores the first information and the second information, and a control unit that provides an announcement of the lifespan of the charging roller based on the first information and the second information acquired by the acquisition unit.

Description

[Technical Field]

[0001] This invention relates to an image forming apparatus that utilizes an electrophotographic recording method, such as a laser printer, copier, or facsimile. An image forming apparatus forms an image on a recording medium using an image forming process, such as an electrophotographic process, an electrostatic recording process, or a magnetic recording process. Examples include copiers, printers (LED printers, laser beam printers, etc.), facsimile machines, word processors, and combined functions thereof. [Background technology]

[0002] The image formation process for electrophotographic recording systems such as laser printers, copiers, and facsimile machines is carried out as follows: The surface of the photosensitive drum is uniformly charged by a charging means. The charged surface of the photosensitive drum is exposed by an exposure means to form an electrostatic latent image. This electrostatic latent image is then developed by a developing means having a developer carrier to form a toner image on the surface of the photosensitive drum using a developer (hereinafter referred to as toner). This toner image is then transferred to a recording material by a transfer means. After that, the toner image is fixed onto the recording material by a fixing means and output as a printed product.

[0003] In recent years, photosensitive drums, charging means, developing means, etc., are often integrated into a single cartridge and designed to be detachable from the image forming apparatus. This is because, when the photosensitive drum, charging means, developing means, etc., wear out and the image forming apparatus may malfunction or produce poor images (hereinafter referred to as "lifespan"), the cartridge can be detached from the image forming apparatus and replaced with a new cartridge, allowing for normal image formation to resume. Furthermore, it is common practice to detect or predict the lifespan of various components, and to notify the user and prompt them to replace the cartridge when any one of them reaches the end of its lifespan. Patent Document 1 describes a method in which the operating time of various components is accumulated, and when it exceeds a specified amount, it is determined that the lifespan of that component has been reached, and a notification is issued to prompt action such as replacement. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5093143 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, Patent Document 1 had the following problem: In the case of contact charging, where a charging roller, which is a charging means, is brought into contact with the photosensitive drum to perform charging, the charging performance of the charging roller may decrease due to wear. The state in which the charging performance decreases is one example of an indicator that the charging roller has reached the end of its lifespan.

[0006] This invention has been made in view of the above points, and aims to provide a technology for determining the lifespan of a charging roller and replacing the charging roller at an appropriate time in an image forming apparatus that performs contact charging using a charging roller. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides an image forming apparatus comprising: a rotatable image carrier; a rotatable charging roller that contacts the image carrier and forms a charging portion, and charges the surface of the image carrier with the charging portion; a developing apparatus that includes a storage portion for storing a developer with an external additive added to its surface, and supplies the developer stored in the storage portion to the surface of the image carrier that has been charged by the charging roller; a drive unit for rotating the image carrier and the charging roller; an acquisition unit for acquiring first information regarding the usage history of the charging roller and second information regarding the usage history of the developing apparatus; a memory for storing the first information and the second information; and a control unit that provides lifespan notification for the charging roller based on the first information and the second information acquired by the acquisition unit. [Effects of the Invention]

[0008] In an image forming apparatus that performs contact charging using a charging roller, this technology can provide a way to determine the lifespan of the charging roller and replace it at the appropriate time. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing the overall structure of the image forming apparatus in Example 1. [Figure 2] This is a control block diagram of the image forming apparatus in Example 1. [Figure 3] This is a perspective view showing the PC and portable information processing terminal connected to the image forming apparatus in Example 1. [Figure 4] This flowchart shows the life determination control of the electrostatic roller in Example 1. [Figure 5] This is a schematic cross-sectional view showing the overall structure of the image forming apparatus in Example 2. [Figure 6] This is a flowchart of the recycling determination method in Example 2. [Modes for carrying out the invention]

[0010] Preferred embodiments of this invention will be described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments are not intended to limit the scope of this invention to those components alone. Furthermore, unless otherwise specified, the materials, shapes, etc., of the components described once in the following description will be the same as those described in the initial description. Well-known or prior art in the relevant field can be applied to configurations and processes that are not specifically illustrated or described. Also, redundant explanations may be omitted. [Examples]

[0011] (Overall configuration of the image forming apparatus) The overall configuration of the image forming apparatus will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view of the image forming apparatus according to the present invention, and each component is shown in a simplified manner.

[0012] The image forming apparatus 100 according to this embodiment includes a photosensitive drum 1 as a photoreceptor, a charging roller 2 as a charging device, an exposure device 3, a developing device 4, a transfer device 5, a fixing device 6, a cleaning device 7, and the like. The charging roller 2 charges the surface of the photosensitive drum 1. The scanner unit 3 as an exposure device exposes the charged photosensitive drum 1 to form an electrostatic latent image corresponding to image information on its surface. The developing device 4 develops the electrostatic latent image formed on the surface of the photosensitive drum 1 with toner T as a developer. The developing device 4 includes the following components: a developing member, a developing roller 41 as a developer carrier, a supply roller 42 that rotates in contact with the developing roller 41, a developing blade 43 as a restricting member that restricts the toner T carried on the surface of the developing roller 41, and a developing container 44 that contains the toner T. The transfer roller 5 as a transfer device contacts the photosensitive drum 1 and transfers the toner image to the recording material R. The fixing device 6 heats and pressurizes the recording material R to fix the toner image onto the recording material R. Each component will be described below.

[0013] The photosensitive drum 1 is an image carrier in which a negatively charged organic photoreceptor is molded on a conductive cylinder at ground potential. The photosensitive drum 1 is a φ24 mm cylinder and is rotationally driven by the motor drive unit 223 shown in Figure 2 in a predetermined direction (clockwise direction in Figure 1: arrow E) at a predetermined peripheral speed (referred to as the process speed). The process speed of the photosensitive drum 1 in this embodiment is 139 mm / sec.

[0014] The charging roller 2 is formed by cylindrically molding a conductive resin around a metallic core bar. The charging roller 2 contacts the rotating photosensitive drum 1 with a predetermined pressure contact force, and a predetermined charging voltage is applied from the high-voltage power supply 224 shown in FIG. 2 to charge the surface of the photosensitive drum 1 to a predetermined potential. The charging roller 2 rotates in a driven manner with respect to the rotation of the photosensitive drum 1. In this embodiment, the photosensitive drum 1 is charged to a negative polarity by the charging roller 2. In Example 1, the photosensitive drum 1 is charged by applying a DC voltage of, for example, -1350 V to the charging roller 2, and the surface potential of the photosensitive drum 1 at that time is approximately -700 V. Note that the voltage applied to the charging roller 2 is not limited to a DC voltage, and it is also possible to apply an AC voltage and control it with a constant current. Also, the charging roller 2 and the motor driving unit 223 of the photosensitive drum 1 may be independently driven by separate motor driving units, or a peripheral speed difference may be provided between the charging roller 2 and the photosensitive drum 1.

[0015] The exposure device 3 is an exposure means for performing exposure corresponding to image information input from an external device or a reading device. As the exposure device 3, it is also possible to use a laser scanner unit that scans the surface of the photosensitive drum 1 with a semiconductor laser, an LED exposure device having an LED array in which a plurality of LEDs are arranged along the longitudinal direction of the photosensitive drum 1, and the like. In this embodiment, a laser scanner unit is used as the exposure device 3.

[0016] The developing device 4 is developing means including a developing roller 41, a supply roller 42 capable of supplying developer to the developing roller 41, a developing blade 43 as a regulating member for regulating the amount of developer, and a developing container 44 serving as a frame of the developing device 4. The developing roller 41 serving as a developer carrier for carrying the developer and the supply roller 42 which is a toner supply member are rotatably supported by the developing container 44. In this embodiment, the developing container 44 serving as a toner storage section can store 280 g of toner T. Further, the developing roller 41 is disposed at an opening of the developing container 44 so as to face the photosensitive drum 1. The supply roller 42 has a configuration in which a foamed elastic body of continuous foam is formed around a metal core. The supply roller 42 is in contact with the developing roller 41 and is disposed rotatably. The developing roller 41 and the supply roller 42 rotate in a direction opposite to the rotation direction of the photosensitive drum 1. The developing roller 41 rotates while abutting on the surface of the photosensitive drum 1 at a peripheral speed ratio of 140% with respect to the rotation speed of the photosensitive drum 1. The developing device 4 attaches toner T charged with the same polarity as the charging polarity of the photosensitive drum 1 to portions (image portions, exposure portions) where the charge has decayed due to exposure on the surface of the photosensitive drum 1, thereby forming a toner image which is a developer image. In Example 1, the developing device 4 contains toner T as a non-magnetic one-component developer whose normal charging polarity (charging polarity for developing an electrostatic latent image) is negative polarity. The developing device 4 of this embodiment uses a contact developing method as the developing method. That is, the toner layer carried on the developing roller 41 contacts the photosensitive drum 1 in the developing area. A developing voltage is applied to the developing roller 41 by a high-voltage power source 224. Under the application of the developing voltage, the toner T carried on the developing roller 41 transfers from the developing roller 41 to the surface of the photosensitive drum 1 according to the potential on the surface of the photosensitive drum 1, whereby the electrostatic latent image is developed into a toner image.

[0017] Also, in order to improve fluidity, chargeability, cleaning property, etc. of the toner T, a fluidizing agent and a cleaning aid which are additives (hereinafter, external additives) are added to the toner T.

[0018] Examples of external additives include inorganic oxide microparticles such as silica microparticles, alumina microparticles, and titanium oxide microparticles; inorganic stearic acid compound microparticles such as aluminum stearate microparticles and zinc stearate microparticles; and inorganic titanate compound microparticles such as strontium titanate and zinc titanate microparticles. These can be used individually or in combination of two or more. These inorganic microparticles are preferably treated with a gloss finish using silane coupling agents, titanium coupling agents, higher fatty acids, silicone oils, etc., to improve heat resistance and environmental stability. The BET specific surface area of ​​the external additive is 10 m². 2 / g or more 450m 2 It is preferable that the value be less than or equal to / g.

[0019] The BET specific surface area can be determined by a low-temperature gas adsorption method using a dynamic constant-pressure method, according to the BET method (preferably the BET multi-point method). For example, by using a specific surface area measuring device (product name: Gemini 2375 Ver. 5.0, manufactured by Shimadzu Corporation), nitrogen gas is adsorbed onto the sample surface, and the BET specific surface area (m²) is measured using the BET multi-point method. 2 It is possible to calculate ( / g).

[0020] The total amount of these various external additives added is 0.05 parts by mass or more and 5 parts by mass or less, preferably 0.1 parts by mass or more and 3 parts by mass or less, per 100 parts by mass of toner. Furthermore, various external additives may be used in combination.

[0021] In Example 1, a voltage corresponding to the temperature and humidity of the image forming apparatus 100 is applied. In an environment with a temperature of 23°C, a DC voltage of -350V is applied to the developing roller 41, -450V to the supply roller 42, and -450V to the developing blade 43. Since the normal charge polarity of the toner T in Example 1 is negative, the potential difference between the supply roller 42 and the developing roller 41 is such that the toner T is biased (moves) from the supply roller 42 side to the developing roller 41 side. In this example, the potential difference between the supply roller 42 and the developing roller 41 is variably controlled according to the operating environment and the degree of deterioration of the supply roller 42. This control stabilizes the supply of toner T from the supply roller 42 to the developing roller 41.

[0022] On the other hand, the potential difference between the developing blade 43 and the developing roller 41 is such that the toner T is biased from the developing blade 43 side towards the developing roller 41 side. This stabilizes the intake of toner T into the contact area between the developing blade 43 and the developing roller 41, and also stabilizes the application of a charge to the toner T by the developing blade 43.

[0023] As an example of the toner T in this embodiment, a polymerized toner produced by polymerization, having a particle size of 6 μm and spherical in shape, with negative polarity as the normal charge polarity, can be used. Furthermore, the toner T in this embodiment does not contain magnetic components and is a so-called non-magnetic one-component developer, in which the toner T is mainly supported on the developing roller 41 by intermolecular forces and electrostatic forces. In addition, as mentioned above, the one-component developer may contain additives (e.g., wax or silica fine particles) to adjust the fixability and charging performance of the toner T, in addition to the toner particles. Alternatively, a magnetic one-component developer containing magnetic components or a two-component developer composed of non-magnetic toner T and a magnetic carrier may be used as the developer. When using a magnetic developer, for example, a cylindrical developing sleeve with a magnet placed inside can be used as the developer carrier.

[0024] The transfer roller 5, acting as a transfer device, receives a transfer voltage from the high-voltage power supply 224. The transfer roller 5 is a transfer means that transfers the toner image supported on the photosensitive drum 1 onto the recording material R. The transfer roller 5 is rotationally driven by the motor drive unit 223. The recording material R, onto which the toner image has been transferred, is transported to the fuser device 6.

[0025] The fixing device 6 is a thermal fixing method fixing means that performs image fixing by heating and melting the toner T on the recording material R. The fixing device 6 comprises a fixing film 6a, a fixing heater 6b such as a ceramic heater for heating the fixing film, and a pressure roller 6c for pressing against the fixing film. A thermistor for measuring the temperature of the fixing heater 6b is provided inside the fixing film. The recording material R that has passed through the fixing device 6 is discharged to the outside of the image forming apparatus 100 (outside the machine) and loaded onto an output tray 28 formed on the top of the printer body.

[0026] The cleaning device 7 is a cleaning means that removes toner T (transfer residue toner) that remains on the surface of the photosensitive drum 1 because it was not completely transferred by the transfer means. The cleaning device 7 removes toner T by having a cleaning blade 71, which is an elastic rubber blade positioned in contact with the photosensitive drum 1 with its tip facing upstream in the direction of rotation (arrow E). In this embodiment, the material of the cleaning blade 71 that contacts the photosensitive drum 1 is urethane rubber, but it is not limited to this, and any polymer rubber elastic material such as chloroprene rubber, ethylene propylene diene rubber, or nitrile rubber may be used. Alternatively, a developing and cleaning method may be used in which the transfer residue toner is recovered by the developing device 4 without installing the cleaning device 7.

[0027] The image forming apparatus 100 may be a multi-color system capable of forming images using multiple toners T (for example, four colors: cyan C, magenta M, yellow Y, and black K). In this case, the image forming apparatus 100 is equipped with an image forming unit for each of the multiple toners, which forms an image on the surface of the photosensitive drum 1 using toner T supplied from the developing apparatus 4. In this case, it is also preferable to use an intermediate transfer method in which multiple toner images are superimposed and formed on an intermediate transfer belt, and then transferred to the recording material R.

[0028] The image forming apparatus 100 in Example 1 may employ a process cartridge 10, which combines the photosensitive drum 1, charging roller 2, cleaning device 7, and developing device 4 into a cartridge that can be attached to and detached from the main body of the image forming apparatus (see Figure 5 in Example 2). Alternatively, the drum cartridge containing the photosensitive drum 1, charging roller 2, and cleaning device 7, and the developing device 4 may be configured as a developing cartridge, each separately attachable to and detached from the image forming apparatus 100.

[0029] (Control block diagram) The control configuration of the image forming apparatus 100 will be explained using the block diagram in Figure 2.

[0030] The main controller 201 shown in Figure 2 has a control unit 220 (central processing unit) as a control means, which is the central element for performing calculations. It also has a main memory 221 such as ROM and RAM as a storage means, and an input / output (I / O) interface (I / F) 222 for input and output of information with peripheral devices. The ROM of the main memory 221 stores control programs in advance, such as a program to calculate the lifespan of the charging roller 2 and a program to calculate the remaining toner amount, which will be described later. The control unit 220 is a control means that comprehensively controls the operation of the image forming apparatus 100, and each control target in the image forming apparatus 100 is connected via the input / output I / F 222. The control unit 220 controls the exchange of various electrical information signals and the timing of drives, and is in charge of the processing of the flowchart described later. The motor drive unit 223 refers to various motors and is a power source for rotating the polygon scanner, photosensitive drum 1, developing roller 41, supply roller 42, etc., located inside the scanner unit 3, and operates based on control signals from the control unit 220. The high-voltage power supply 224 is a power source that applies high voltage to the photosensitive drum 1, charging roller 2, developing roller 41, supply roller 42, transfer roller 5, fixing device 6, etc. In this embodiment, the high-voltage power supply 224 includes a charging voltage application unit that applies a charging voltage to the charging roller 2 and a developing voltage application unit that applies a developing voltage to the developing roller 41. The charging voltage application unit and the developing voltage application unit may each be configured as independent high-voltage power supplies. The temperature and humidity sensor 225 is a sensor for detecting the temperature and humidity of the environment in which the image forming apparatus 100 is used, and is used to change the control according to the detected temperature and humidity. The non-volatile memory 8, which is located in the image forming unit such as the process cartridge 10, is connected to the main unit controller 201 via the memory communication unit 226, which acts as an acquisition unit, and information can be read and written. In this embodiment, a non-contact non-volatile memory is used as the storage means, but for example, a contact non-volatile memory, a non-contact non-volatile memory, or a volatile memory with a power supply can be used as an appropriate means.

[0031] (Determining the lifespan of the electrostatic roller) In the image forming apparatus 100 having the above configuration, the following control for determining the lifespan of the charging roller 2 and notification, which is a characteristic of this embodiment, is performed.

[0032] In contact charging, where the photosensitive drum 1 is charged by contacting the charging roller 2, wear and tear can reduce the charging performance of the charging roller 2, causing localized abnormalities and resulting in stronger localized charging. This can lead to the occurrence of white spot-like abnormal images (hereinafter referred to as white spots or white spot images). While the charging roller 2 uniformly charges the surface of the photosensitive drum 1, in situations where white spots occur, excessive discharge occurs at the white spot areas on the surface of the charging roller 2, increasing the absolute value of the potential on the surface of the photosensitive drum 1. That is, the surface potential of the photosensitive drum 1 increases in the negative direction, which is the normal charging polarity of toner T. As a result, the amount of toner developed on the surface of the photosensitive drum 1 decreases, forming white spot-like patterns and significantly degrading image quality. Therefore, in this embodiment, the user is notified that the charging roller 2 and process cartridge 10 have reached the end of their lifespan before white spots occur. An example of user notification is the notification using a PC (Personal Computer) 300 or a portable information processing terminal 301, as shown in Figure 3. For example, the image forming apparatus 100 is communicably connected to an information processing device such as a PC 300 or a portable information processing terminal 301 such as a smartphone. Information transmitted from the PC 300 and the portable information processing terminal 301 to the image forming apparatus 100 is input to the control unit 220 via the input / output (I / O) interface 222. Information transmitted from the image forming apparatus 100 to the PC 300 or the portable information processing terminal 301 is input from the control unit 220 to the control unit of the PC 300 or the portable information processing terminal 301 via the I / O interface 222. The PC 300 and the portable information processing terminal 301 may be configured to have sound-producing units such as speakers. The notification may be displayed on the display unit 303, which is a notification unit as the first display means of the PC 300, or on the display unit 304, which is a notification unit as the first display means of the portable information processing terminal 301, or on the display unit 302, which is a notification unit located in the image forming apparatus 100. Furthermore, the above notification message may be displayed on two or more of the display units 302, 303, and 304.

[0033] If an abnormality occurs due to another electrostatic roller 2, that abnormality may also be detected or predicted, and notification may be provided accordingly.

[0034] The main causes of excessive discharge at the white dots on the surface of the charging roller 2 are the increased resistance of the charging roller 2 and the adhesion of external additives added to the toner T to the surface of the charging roller 2.

[0035] First, let's explain the increase in resistance of the charging roller 2. Table 1 shows the charging voltage in the rows and the surface travel distance of the charging roller 2, converted to the number of A4 printed sheets, in the columns, which is information about the rotation speed of the charging roller 2. It shows the resistance of the charging roller 2 when a specified number of sheets are printed using each charging voltage. Here, the surface travel distance of the charging roller 2 is the sum of the distance the photosensitive drum 1 rotates while the photosensitive drum 1 is charged after a charging voltage is applied to the charging roller 2. In other words, the surface travel distance of the charging roller 2 is an indicator of the deterioration information of the charging roller 2 related to its operating time. When the photosensitive drum 1 is charged, current flows through the charging roller 2, causing a change in the material composition of the charging roller 2 and increasing its resistance. Table 1 shows that this increase in resistance occurred when printing the equivalent of 5,000, 10,000, and 15,000 sheets compared to a new roller. Furthermore, it also shows that the larger the absolute value of the charging voltage applied to the charging roller 2, the greater the increase in resistance. The following results are from image formation tests conducted using the image forming apparatus 100 of this embodiment under conditions of 23°C and 50% relative humidity. The print density was set to 1%.

[0036] As described above, the resistance increase of the charged roller 2 can be predicted using the surface travel distance of the charged roller. Therefore, we decided to use the surface travel distance of the charged roller as the first indicator (first information L1, described later) regarding the usage history of the charged roller 2.

[0037] [Table 1]

[0038] Next, the adhesion of external additives to the surface of the charging roller 2 will be explained. Table 2 shows the amount of toner in the developing container 44 in the rows, the value of the developing roller surface travel distance converted to the number of A4 printed sheets in the columns, and the Si intensity of fluorescent X-rays indicating the amount of silica used as an external additive that adhered to the charging roller 2. The Si intensity of fluorescent X-rays was measured using the Vanta handheld fluorescent X-ray analyzer (VMR-CCC-G3-J-JA) from Olympus Corporation / Evident Co., Ltd. The Si intensity of fluorescent X-rays is an index that correlates with the amount of silica adhered to the surface of the charging roller 2. The developing roller surface travel distance is the sum of the distance traveled by the photosensitive drum 1 and the developing roller 41 when contact developing with a single-component developer is used, while the photosensitive drum 1 and the developing roller 41 are in contact and the developing process is possible. Incidentally, in the case of the non-contact developing method, an AC voltage is applied to move toner between the photosensitive drum 1 and the developing roller 41, and the value is the sum of the distance the photosensitive drum 1 and the developing roller 41 rotate while the developing process is in a state where it is possible to develop. In these states where the developing process is possible, the toner T comes into contact with the photosensitive drum 1, so there is a possibility that the external additives attached to the toner T will transfer to the photosensitive drum 1. Table 2 shows the Si intensity of fluorescent X-rays when printing 1000, 2000, and 3000 full-white images equivalent to a new product, i.e., when no toner image is formed on the surface of the photosensitive drum 1 (a state with a print density of 0%). It can be seen that the amount of silica attached to the charging roller 2 increases as the number of printed sheets increases. Furthermore, it is shown that when there is a large amount of toner T filled in the developing container 44, the total amount of external additives in the developing container 44 is also large, and therefore the amount of external additives attached to the charging roller 2 is also large. In this embodiment, the evaluation was performed with the printing rate, which is the most severe in terms of external additive adhesion, set to 0%. However, the trend in Table 2 remains the same even when the printing rate is greater than 0%. In other words, when comparing the case of the first printing rate with the case of the second printing rate, which is greater than the first printing rate, the control unit 220 may be controlled so that the timing of the life notification of the charging roller 2 is earlier for the second printing rate than for the first printing rate. That is, information on the printing rate may be added as a third piece of information L3, which is different from the first piece of information L1 and the second piece of information L2 described in Example 1.However, in that case, it should be considered that toner consumption will depend on the printing rate. In other words, if the printing rate remains constant, the timing of the life notification for the charging roller 2 may be controlled so that a larger initial amount of toner contained in the developing container 44 results in an earlier notification.

[0039] As described above, the amount of external additive adhering to the surface of the charging roller 2 can be predicted using the surface travel distance of the developing roller. Therefore, we decided to use the surface travel distance of the developing roller as a second indicator (second information L2, described later) regarding the usage history of the charging roller 2.

[0040] [Table 2]

[0041] Furthermore, Table 3 shows the relationship between the first indicator, the resistance of the charging roller 2, the second indicator, the fluorescence X-ray Si intensity, and the white spots. When an image is printed on the recording material R, ○ indicates a normal image is printed, and × indicates a state where white spots occur. × indicates a state where white spots occur when either the resistance of the charging roller 2 or the adhesion of the external additive occurs, that is, when the charging roller 2 is worn out.

[0042] [Table 3]

[0043] Table 3 shows that white spots are more likely to occur when the resistance of the charging roller 2 (the first indicator) increases, or when the fluorescence X-ray Si intensity (the second indicator) is high. On the other hand, even if the resistance of the charging roller 2 (the first indicator) increases, white spots will not occur if the fluorescence X-ray Si intensity (the second indicator) is low. Also, if the increase in the resistance of the charging roller 2 (the first indicator) is small, white spots will not occur even if the fluorescence X-ray Si intensity (the second indicator) is high. The state in which the charging roller 2 is worn out, that is, the time to replace the charging roller 2, is determined by the balance between the resistance of the charging roller 2 (the first indicator) and the fluorescence X-ray Si intensity (the second indicator).

[0044] Next, we compare Examples 1-1 and 1-2, which predict the lifespan of the charging roller 2 by calculating both the resistance value and the adhesion of the external additive, with Comparative Example 1, which predicts the lifespan by calculating only the resistance value of the charging roller 2. In Comparative Example 1, the lifespan of the charging roller 2 was determined to be when its resistance exceeded 12.0 GΩ / mm.

[0045] Table 4 shows the results of the comparative test. Under the comparison conditions, a charging voltage of -1350V was applied to the charging roller 2, and a cartridge filled with 280g of toner was used to print two A4 sheets intermittently. The printed images used were a full-white image with 0% print density and an image pattern with 5% print density.

[0046] [Table 4]

[0047] When the print density is 0%, after printing 10,000 sheets, the resistance of the charging roller 2 exceeds 12.0 GΩ / mm, and the amount of external additive adhering exceeds 2.0% Si strength. Therefore, in Example 1-1, the control unit 220 determines that the charging roller 2 has reached the end of its lifespan at that point. Similarly, in Comparative Example 1 with a print density of 5%, the control unit 220 also determines that the charging roller 2 has reached the end of its lifespan because its resistance exceeds 12.0 GΩ / mm. However, in reality, the amount of external additive adhering has not reached 2.0% Si, and the charging roller 2 is still usable. Nevertheless, the control unit 220 issues a lifespan notification requesting replacement. On the other hand, in Example 1-2, after printing 10,000 sheets of an image pattern with a print density of 5%, the control unit 220 does not issue a lifespan notification. In Example 1-2, because both the resistance of the charging roller 2 and the amount of external additive adhering to the charging roller 2 are considered, it is possible to accurately predict that the charging roller 2 is still usable. Therefore, there is no need to request the replacement of the usable charging roller 2.

[0048] Based on the above, by combining the charging time as the first indicator for predicting the resistance of the charging roller 2 and the developing time as the second indicator for predicting the adhesion of the external additive to the surface of the charging roller 2, it is possible to predict the state of white spot formation on the charging roller 2.

[0049] (Control method) Next, the specific control method of this embodiment will be described. In the control unit 220 of this embodiment, the wear degree, which is the first piece of information relating to the resistance of the charging roller 2, is defined as L1, and the wear degree, which is the second piece of information relating to the adhesion of external additives to the surface of the charging roller 2, is defined as L2. It is calculated using the charging time of the charged state, which is the time when the charging roller 2 is rotating while a charging voltage is applied, and the developing time of the developed state, which is the time when the photosensitive drum 1 and the developing roller 41 are in contact and the developing roller 41 is rotating while a developing voltage is applied.

[0050] The method for calculating the first piece of information L1 in this embodiment will be explained.

[0051] The resistance of the charging roller 2 increases with charging time. The following relationship was used as the change in L1 ΔL1 over time Δt. ΔL1 = a1 × f1(Vpri) × Δt (Equation 1)

[0052] In Equation 1, the constant a1 related to the first index is a value regarding the ease of occurrence of white spots due to the speed of energization deterioration and the degree of energization deterioration of the charging roller 2. The rotation speed of the charging roller 2 described above can also be regarded as a part of the constant a1. f1(Vpri) is a correction value for the difference in the speed of energization deterioration depending on the charging voltage Vpri. For f1(Vpri), for example, when |Vpri|≧Vth, f1(Vpri)=|Vpri|-Vth can be set. Vth is the breakdown voltage of the gap between the charging roller 2 and the photosensitive drum 1, that is, the discharge start voltage, and is a constant of about 500V in an atmospheric pressure environment. This is because it is equivalent to a closed circuit in which a voltage of |Vpri|-Vth is applied to the surfaces of the charging roller 2 and the photosensitive drum 1. Also, when the charging voltage is not applied or discharge does not occur, that is, when |Vpri|<Vth, energization deterioration is unlikely to occur, so f1(Vpri = 0V)=0 is set. As an example of this embodiment, when f1(Vpri=-1350V)=1.0 when the charging voltage of -1350V is applied, f1(Vpri=-1300V)=0.95 when the charging voltage of -1300V is applied, and f1(Vpri=-1400V)=1.05 when the charging voltage of -1400V is applied. Also, the value of f1(Vpri) may be changed according to the result of the temperature and humidity sensor 225. For example, since the resistance of the charging roller 2 is higher in a low temperature and low humidity environment (L / L) (15°C / 10%) than in a high temperature and high humidity environment (H / H) (30°C / 90%), even with the same charging voltage, correction such as setting f1(Vpri) larger may be performed. In that case, a value such as the environmental coefficient α1 may be prepared separately and used as α1(L / L)×f1(Vpri). In that case, it is needless to say that it is set so that α1(L / L)>α1(H / H).

[0053] Next, the calculation method of the second information L2 in this embodiment will be described.

[0054] The adhesion amount of the external additive to the charging roller 2 increases with the development time. The following relational expression was used as the change amount ΔL2 of L2 during the time Δt2. ΔL2=a2×f2(mt)×Δt2 (Equation 2)

[0055] The constant a2 related to the second indicator is a value relating to the likelihood of white spots occurring depending on the amount of external additive adhering to the charging roller 2. In this embodiment, the degree to which the external additive adheres to the charging roller 2 varies depending on the amount of toner T in the developing container 44, and the more toner T there is, the more external additive is supplied to the charging roller 2.

[0056] f2(mt) is a correction value that compensates for the difference in the rate at which external additives adhere to the charging roller 2 depending on the amount of toner remaining. In this embodiment, the toner remaining amount is managed by the control unit 220 predicting the amount of toner consumed for each image from the print image data and subtracting the toner amount data corresponding to the amount of toner filled, which is recorded in the main memory 221. f2(mt) is calculated using this toner amount data. As an example in this embodiment, if f2(mt) = 1.0 when the toner remaining amount is 280g, then f2(mt) = 0.9 when the toner remaining amount is 260g, and f2(mt) = 0.8 when the toner remaining amount is 240g. The value of f2(mt) may also be changed according to the results of the temperature and humidity sensor 225. For example, in a low-temperature, low-humidity environment (L / L) (15°C / 10%), the electrostatic and non-electrostatic adhesion of the external additive to the photosensitive drum 1 will be higher than in a high-temperature, high-humidity environment (H / H) (30°C / 90%), so a correction such as setting f2(mt) to a larger value may be made. In that case, a separate value such as the environmental coefficient α2 may be prepared and used as α2(L / L) × f2(mt). Needless to say, in that case, it should be set so that α2(L / L) > α2(H / H).

[0057] Furthermore, the toner level detection method is not limited to this, and other methods may be used, such as an optical toner level detection system that installs an optical window in a part of the developing container 44, detects the presence or absence of toner on the optical axis using an LED and a light-receiving element, and detects the amount of toner in the developing container 44.

[0058] Using L1 and L2 derived as described above, the control unit 220 determines the lifespan of the charging roller 2 as follows.

[0059] When using the preset life threshold L of the charging roller 2, the conditions for determining the life of the charging roller 2 are L < L1 + L2 (Equation 3) is set. The life threshold L may use different values depending on the operating environment and the like. By doing so, it is possible to accurately predict the occurrence of white spot images and the life of the charging roller 2, to which both the energization deterioration of the charging roller 2 and the adhesion of the external additive contribute.

[0060] Note that Equation 3 is an example, and it is only necessary to be able to compare L with a function of L1 and L2. For example, either L1 or L2 may be weighted by multiplying by a coefficient, or the product of L1 and L2 may be used.

[0061] Next, using the flowchart of FIG. 4, the life prediction control of the charging roller 2 in the image forming sequence of this embodiment will be described.

[0062] L, L1, and L2 are recorded in the nonvolatile memory 8 provided in the process cartridge 10, and L1 and L2 are updated according to the operation of the image forming apparatus 100. Note that the data of L, L1, and L2 may be stored in the main body memory 221. Also, the life threshold L of the charging roller 2 may not be provided, and the life of the charging roller 2 may be determined only from the results of L1 and L2.

[0063] The control unit 220 controls to start the image forming sequence upon receiving an image forming command from the controller 201. The control steps are as follows. S1: The control unit 220 controls to read L1 and L2 of the nonvolatile memory 8 via the memory communication unit 226. S2: The control unit 220 controls the high voltage power supply 224 and the motor drive unit 223 at an appropriate timing to start image formation. S3: The control unit 220 controls to check the presence or absence of the charged state every sampling period Δt. S4: In S3, if the control unit 220 determines that the charging voltage is applied to the charging roller 2 by the high-voltage power supply 224 and the photosensitive drum 1 is rotating by the motor drive unit 223 (i.e., in the charging state), it calculates ΔL1 from Equation 1 (S3 Yes). Then, it controls to store it in the main memory 221 or the non-volatile memory 8 as Σ(ΔL1) in Equation 4. In S3, if the control unit 220 determines that it is not in the charging state, it controls to proceed to S5 (S3 No). ΔL1 = a1 × f1(Vpri) × Δt (Equation 1) Σ(ΔL1) n = Σ(ΔL1) n-1 + ΔL1 (Equation 4) S5: The control unit 220 controls to check the presence or absence of the developing state at each sampling period Δt. S6: In S5, if the control unit 220 determines that the developing voltage is applied to the developing roller 41 by the high-voltage power supply 224 and the developing roller 41 is rotating by the motor drive unit 223 (i.e., in the developing state), it calculates ΔL2 from Equation 2 (S5 Yes). Then, it controls to store it in the main memory 221 or the non-volatile memory 8 as Σ(ΔL2) in Equation 5. In S5, if the control unit 220 determines that it is not in the developing state, it controls to proceed to S7 (S5 No). ΔL2 = a2 × f2(mt) × Δt (Equation 2) Σ(ΔL2) n = Σ(ΔL2) n-1 + ΔL2 (Equation 5) S7: If the control unit 220 determines that the image forming operation continues, it controls to return to S3 (S7 Yes). If the control unit 220 determines that the image forming operation does not continue, it controls to proceed to S8 (S7 No). S8: The control unit 220 controls to update the values stored in the main memory 221 or the non-volatile memory 8 as L1 ⇒ L1 + Σ(ΔL1) n , L2 ⇒ L2 + Σ(ΔL2) n ​S9: The control unit 220 controls to determine whether or not the condition L < L1 + L2 in Equation 3 is satisfied. When the control unit 220 satisfies the condition L < L1 + L2 in Equation 3, it proceeds to S10 (S9 Yes). When the control unit 220 does not satisfy the condition L < L1 + L2 in Equation 3, it controls to end the flow of the image formation sequence (S9 No). S10: In S9, when L < L1 + L2 is satisfied, the control unit 220 determines that the charging roller 2 has reached the end of its life and controls to cause a notification to that effect to be displayed on the display unit 303 as the first display means of the PC 300, the display unit 304 as the first display means of the portable information processing terminal 301, and the like.

[0064] After S9 No and S10, the image formation sequence is ended and the system shifts to standby. In the case after S10, the notification to the display unit 304 continues to prompt the user to replace the charging roller 2. Thereafter, the user may be freely allowed to select whether or not to replace the charging roller 2.

[0065] The features of the image forming apparatus 100 described in the first embodiment are as follows.

[0066] The device includes a rotatable photosensitive drum 1 and a rotatable charging roller 2 that contacts the photosensitive drum 1 to form a charged portion and charges the surface of the photosensitive drum 1 with the charged portion. The device also includes a developing container 44 which contains toner T with an external additive added to its surface, and a developing device 4 which supplies the toner T contained in the container 44 to the surface of the photosensitive drum 1 that has been charged by the charging roller 2. The developing device 4 includes a rotatable developing roller 41 which faces the surface of the photosensitive drum 1 and supplies the toner T to the surface of the photosensitive drum 1. The developing roller 41 rotates in contact with the photosensitive drum 1 at the opposing portion. The device also includes a high-voltage power supply 224 which applies a charging voltage and a developing voltage to the charging roller 2 and the developing roller 41. The device also includes a motor drive unit 223 for rotating the photosensitive drum 1 and the charging roller 2, a memory communication unit 226 for acquiring first information L1 regarding the usage history of the charging roller 2 and second information L2 regarding the usage history of the developing device 4, and a recording memory 8 for storing the first information L1 and the second information L2. The system includes a control unit 220 that provides a lifetime notification for the charging roller 2 based on a first piece of information L1 and a second piece of information L2 acquired by the memory communication unit 226. The notification may be displayed on the display unit 303 of the PC 300 as the first display means, or on the display unit 304 of the portable information processing terminal 301 as the first display means, or on the display unit 302 located in the image forming apparatus 100.

[0067] The first piece of information L1 is the time when the high-voltage power supply 224 applies a first voltage, which is a charging voltage exceeding the discharge start voltage, to the charging roller 2. The control unit 220 controls the system so that the timing of the charging roller 2's life notification is earlier when the absolute value of the charging voltage applied to the charging roller 2 by the high-voltage power supply 224 is a third voltage, which is greater than the second voltage, than when the absolute value of the charging voltage applied to the charging roller 2 by the high-voltage power supply 224 is a second voltage, which is greater than the first voltage.

[0068] The second piece of information, L2, is the time during which the developing roller 41 is rotating while the developing voltage is applied to the developing roller 41 by the high-voltage power supply 224, and the photosensitive drum 1 and the developing roller 41 are in contact. The control unit 220 controls the system so that the timing of the charging roller 2's lifespan notification is earlier when the amount of toner T in the storage unit 44 is greater than the first amount.

[0069] By controlling the system as described above, the lifespan of the charging roller 2 can be determined with high accuracy, even when the resistance of the charging roller 2 increases and external additives adhere to the charging roller 2. Furthermore, even when the ratio of resistance increase and adhesion of external additives to the charging roller 2 differs significantly, the lifespan of the charging roller 2 can be appropriately predicted because the respective wear degrees L1 and L2 are calculated independently.

[0070] Herein, the method of this embodiment can be applied not only to monochrome printers that can only draw monochrome images, but also to full-color printers such as those using a CMYK four-color system. [Examples]

[0071] Next, we will describe Example 2. The same reference numerals are used for components similar to those in Example 1 described above, and detailed explanations are omitted.

[0072] In this embodiment, an image forming apparatus is used that reuses each component of a process cartridge 10, which is an integrated unit comprising a photosensitive drum 1, a charging roller 2, a developing device 4, a cleaning device 7, and a toner container 44.

[0073] Specifically, the process cartridge 10, which integrates these components, reaches the end of its lifespan when any one of the aforementioned components—the photosensitive drum 1, the charging roller 2, the developing unit 4, or the cleaning unit 7—reaches the end of its lifespan. Therefore, the control unit 220 needs to notify the user of the need to replace the process cartridge 10. However, some of the other components that have not yet reached the end of their lifespan may still be usable. For example, a user who prints many high-density images and consumes a lot of toner T will use up a large amount of toner T in the toner container 44, and the process cartridge 10 will reach the end of its lifespan when the predetermined amount of toner T is used up. On the other hand, for example, the charging roller 2 may have little wear and tear and may still be perfectly usable. Therefore, measures may be taken to separate the usable components from the collected process cartridge 10 and reuse them as components for a new recycled cartridge. Here, although the process cartridge 10 was used in Example 2, it may also be applied to the drum cartridge and developing cartridge, as in Example 1.

[0074] The process cartridge 10, collected from the user as recycled material, has its recording memory 8 read by an external reading device to determine if there are any recyclable components. The reading device may be one that uses a memory communication unit 226, as in Example 1. After disassembling the process cartridge 10, the recyclable components are extracted and used as parts for a new recycled cartridge. Some components are also cleaned before being reused.

[0075] (Judgment method) Figure 6 illustrates how to determine whether the charged roller 2 is recyclable.

[0076] Similar to Example 1, the charging roller 2 will develop charging failure and white spots due to wear. Therefore, the condition in which white spots appear marks the end of the charging roller 2's lifespan.

[0077] The steps for determining whether an item is recyclable are as follows: S11: Read (acquire) the first information L1 and the second information L2 recorded in the recording memory 8 (reading step). S12: Compare the recyclability threshold value Lr with L1 + L2 using the following formula 6 based on the results of the acquired first information L1 and second information L2 (comparison step). Lr < L1 + L2 (Formula 6) S13: When L1 + L2, which is the wear information, is greater than the recyclability threshold value Lr, determine that the charging roller 2 cannot be recycled (S12 Yes) (judgment step). S14: When L1 + L2, which is the wear information, is less than the recyclability threshold value Lr, determine that the charging roller 2 can be recycled (S12 No) (judgment step).

[0078] From the above, in this embodiment, after executing the reading step of reading the first information L1 and the second information L2 stored in the recording memory 8, from the first information L1 and the second information L2, as information for determining whether the charging roller 2 can be recycled, a comparison step of comparing the recyclability threshold value Lr and L1 + L2, which is the wear information, is executed. From the result of the comparison step, a judgment step of judging whether the charging roller 2 can be recycled is performed.

[0079] It is desirable that Lr be a value smaller than the lifespan L used in Example 1. This is because during the recycling process, even if it is still in a usable situation but the lifespan is approaching, the charging roller 2 may reach its lifespan immediately after the user purchases the recycling cartridge.

[0080] <Control and holding information specific to the recycling cartridge> And as the initial value of the recording memory 8 of the recycling cartridge, the value before recycling may be used. By doing so, the usage history before recycling is reflected, and even when the recycling cartridge is used, an accurate lifespan judgment becomes possible.

[0081] Furthermore, it is possible to clean the charging roller 2 before incorporating it into a new cartridge. In this case, cleaning the charging roller 2 reduces the adhesion of external additives, resulting in lower Si strength. This also has the effect of delaying the occurrence of white spots caused by the adhesion of external additives to the charging roller 2. Therefore, when cleaning the charging roller 2, L2, which is information about the adhesion of external additives to the charging roller 2, may be subtracted. This allows the effect of cleaning to be reflected in the life prediction.

[0082] The recycling determination method described in Example 2 is as follows.

[0083] We assume a process unit 10 that can be attached to an image forming apparatus 200 and has a recording memory 8 that stores first information L1 regarding the usage history of a charging roller 2 that charges the surface of a photosensitive drum 1, and second information L2 regarding the usage history of a developing apparatus 4 that supplies toner T with an external additive to the surface of the photosensitive drum 1. We will show a method for determining whether or not the charging roller 2 provided in the process unit 10 can be recycled.

[0084] First, a reading process is performed to read the first information L1 and the second information L2 stored in the recording memory 8. After the reading process, a comparison process is performed to compare the first information L1, the second information L2, and the recycling threshold Lr stored in the recording memory 8. Then, a determination process is performed to determine whether or not it is possible to recycle the charged roller 2 based on the first information L1 and the second information L2.

[0085] Here, the first piece of information L1 is the time at which the high-voltage power supply 224 applies a first voltage, which is a charging voltage exceeding the discharge initiation voltage, to the charging roller 2.

[0086] The second piece of information, L2, is the time during which the photosensitive drum 1 and the developing roller 41 are in contact and the developing roller 41 is rotating, while the developing voltage is applied to the developing roller 41 by the high-voltage power supply 224.

[0087] As described above, when determining whether or not a roller can be recycled, a statically charged roller 2 that does not develop white spots due to wear is detected. This allows for the recycling of the statically charged roller 2 while maintaining high quality.

[0088] The technologies described herein may contribute to the realization of a sustainable society, such as a decarbonized / circular economy.

[0089] Summary of this disclosure This disclosure includes at least the following:

[0090] (Composition 1) A rotatable image carrier, A rotatable charging roller that contacts the image carrier and forms a charging portion, and charges the surface of the image carrier at the charging portion, A developing apparatus comprising a container for containing a developer to which an external additive has been added to the surface, and supplying the developer contained in the container to the surface of the image carrier which has been charged by the charging roller, The image carrier and the charging roller, and a drive unit that rotates them, An acquisition unit that acquires first information regarding the usage history of the charging roller and second information regarding the usage history of the developing device, A memory for storing the first information and the second information, An image forming apparatus characterized by having a control unit that performs life notification of the charging roller based on the first information acquired by the acquisition unit and the second information.

[0091] (Configuration 2) The system further includes a charging voltage application unit that applies a charging voltage to the charging roller, The image forming apparatus according to configuration 1, characterized in that the first information is the time for the charging voltage application unit to apply a first voltage, which is a charging voltage exceeding the discharge initiation voltage, to the charging roller.

[0092] (Composition 3) The image forming apparatus according to configuration 2, characterized in that the control unit controls the timing of the life notification of the charging roller to be earlier when the absolute value of the charging voltage applied to the charging roller by the charging voltage application unit is a third voltage which is greater than the second voltage which is greater than the first voltage which is greater than the control unit.

[0093] (Composition 4) The developing apparatus includes a rotatable developing roller that faces the surface of the image carrier and supplies a developer to the surface of the image carrier, The system further includes a developing voltage application unit that applies a developing voltage to the developing roller, The image forming apparatus according to configuration 1, characterized in that the second piece of information is the time the developing roller rotates while the developing voltage is applied to the developing roller by the developing voltage application unit.

[0094] (Composition 5) The image forming apparatus according to configuration 4, characterized in that the developing roller rotates in contact with the image carrier.

[0095] (Composition 6) The image forming apparatus according to configuration 1, characterized in that the control unit controls the amount of developer in the storage section to such an extent that the timing of the life notification of the charging roller becomes earlier when the amount of developer in the storage section is greater than the first amount.

[0096] (Composition 7) The system further includes a notification unit for notifying the lifespan of the aforementioned charging roller. The image forming apparatus according to configuration 1, characterized in that the control unit provides a notification of the lifespan of the charging roller based on the first information acquired by the acquisition unit and the second information, and the notification unit provides a notification of the lifespan of the charging roller.

[0097] (Composition 8) A recycling determination method for determining whether a charging roller provided in a process unit having a memory that stores first information regarding the usage history of a charging roller that can be attached to an image forming apparatus and charges the surface of an image carrier, and second information regarding the usage history of a developing apparatus that supplies a developing agent with an external additive to the surface of the image carrier, is recyclable, A reading step of reading the first information and the second information stored in the memory, A determination step of determining whether or not the electrostatic roller can be recycled based on the first information and the second information, including, A recycling determination method characterized by the following.

[0098] (Composition 9) The recycling determination method according to configuration 8, further comprising a comparison step of comparing the first information, the second information, and the recycling threshold stored in the memory after the reading step and before the determination step.

[0099] (Composition 10) The recycling determination method according to configuration 8, characterized in that the first information is the time for which the charging voltage application unit applies a first voltage, which is a charging voltage exceeding the discharge initiation voltage, to the charging roller.

[0100] (Composition 11) The recycling determination method according to configuration 8, characterized in that the second piece of information is the time the developing roller is rotating while the developing voltage is applied to the developing roller by the developing voltage application unit. [Explanation of Symbols]

[0101] 1 Photosensitive drum 2 Charging rollers 4. Developing device 8 Recording memory 41 Developing roller 100 Image forming apparatus 220 Control Unit 223 Motor drive unit 226 Memory Communication Unit T Toner

Claims

1. A rotatable image carrier, A rotatable charging roller that contacts the image carrier and forms a charging portion, and charges the surface of the image carrier at the charging portion, A developing apparatus comprising a container for containing a developer to which an external additive has been added to the surface, and supplying the developer contained in the container to the surface of the image carrier which has been charged by the charging roller, The image carrier and the charging roller, and a drive unit that rotates them, An acquisition unit that acquires first information regarding the usage history of the charging roller and second information regarding the usage history of the developing device, A memory for storing the first information and the second information, An image forming apparatus characterized by having a control unit that performs life notification of the charging roller based on the first information acquired by the acquisition unit and the second information.

2. The system further includes a charging voltage application unit that applies a charging voltage to the charging roller, The image forming apparatus according to claim 1, characterized in that the first information is the time for the charging voltage application unit to apply a first voltage, which is a charging voltage exceeding the discharge initiation voltage, to the charging roller.

3. The image forming apparatus according to claim 2, characterized in that the control unit controls the timing of the life notification of the charging roller to be earlier when the absolute value of the charging voltage applied to the charging roller by the charging voltage application unit is a third voltage which is greater than the second voltage which is greater than the first voltage which is greater than the second voltage which is greater than the third voltage which is greater than the first.

4. The developing apparatus includes a rotatable developing roller that faces the surface of the image carrier and supplies a developer to the surface of the image carrier, The system further includes a developing voltage application unit that applies a developing voltage to the developing roller, The image forming apparatus according to claim 1, characterized in that the second piece of information is the time the developing roller is rotating while the developing voltage is applied to the developing roller by the developing voltage application unit.

5. The image forming apparatus according to claim 4, characterized in that the developing roller rotates in contact with the image carrier.

6. The image forming apparatus according to claim 1, characterized in that the control unit controls the amount of developer in the storage section to be greater than the first amount when the amount is a second amount, so that the timing of the life notification of the charging roller becomes earlier.

7. The system further includes a notification unit for notifying the lifespan of the aforementioned charging roller. The image forming apparatus according to claim 1, characterized in that the control unit provides notification of the lifespan of the charging roller based on the first information acquired by the acquisition unit and the second information, and the notification unit provides notification of the lifespan of the charging roller.

8. A recycling determination method for determining whether a charging roller provided in a process unit having a memory that stores first information regarding the usage history of a charging roller that can be attached to an image forming apparatus and charges the surface of an image carrier, and second information regarding the usage history of a developing apparatus that supplies a developing agent with an external additive to the surface of the image carrier, is recyclable, A reading step of reading the first information and the second information stored in the memory, A determination step of determining whether or not the electrostatic roller can be recycled based on the first information and the second information, including, A recycling determination method characterized by the following.

9. The recycling determination method according to claim 8, further comprising a comparison step of comparing the first information, the second information, and the recycling threshold stored in the memory after the reading step and before the determination step.

10. The recycling determination method according to claim 8, characterized in that the first information is the time for which a first voltage, which is a charging voltage exceeding the discharge initiation voltage, is applied to the charging roller.

11. The recycling determination method according to claim 8, characterized in that the second piece of information is the time the developing roller in the developing apparatus is rotating while a developing voltage is applied to it.

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