Image forming device

Abstract

To prevent an image defect caused by developer replenishment in a configuration in which a replenishment container storing developer, with which a developing device is replenished, can be attached to the developing device.SOLUTION: An image forming device has a replenishment container attachable to and detachable from a developing unit and capable of replenishing a storage portion of the developing unit with replenishment developer. A new developing unit is filled with a predetermined amount of initial developer, and the initial developer and the replenishment developer both contain a first external additive and a second external additive and toner particles. If the respective amounts of first external additive and second external additive contained in the initial developer are I1 and I2, the respective amounts of first external additive and second external additive contained in the replenishment developer are H1 and H2, respective coverages of the first external additive and the second external additive in the initial developer are Wpa and Wpb, and respective coverages of the first external additive and the second external additive in the replenishment developer are Wta and Wtb, 0.9<H1 / I1<1.1, 0.9<H2 / I2<1.1, Wta<Wpa, Wtb<Wpb are satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a copying machine, a printer, or a facsimile machine, that uses an electrophotographic or electrostatic recording method. [Background technology]

[0002] In an image forming apparatus, first, an electrophotographic photoreceptor (hereinafter, simply referred to as "photoreceptor"), which is an image carrier uniformly charged by a charging device such as a charging roller, is selectively exposed to light to form an electrostatic latent image. Then, the electrostatic latent image is visualized with toner by a developing device provided with a developing roller, and the toner image is transferred and fixed to a recording material to perform image recording. The photoreceptor, charging device, developing device, cleaning device, etc. may be integrated into a process cartridge that is detachable from the image forming apparatus, or a developing cartridge including a developing device and a photoreceptor cartridge including a photoreceptor may be configured. In addition, since the life of the photoreceptor is becoming longer than that of toner exhaustion due to toner consumption, there are many configurations in which only the toner container, which is replaced frequently, is separated from the developing device and used as a toner cartridge. By using such a cartridge form, it is easy to replenish toner and to replace and maintain various parts such as the photoreceptor that have reached the end of their life.

[0003] As the additive adheres to the toner surface in the developing device, it is affected by agitation in the developing device, shear in the transport section, and friction with the developing blade that regulates the layer thickness of the developing roller as it is used. This can cause the additive to gradually sink into the toner surface, and the state of the additive and toner to change.

[0004] When the toner in the developing device becomes low and the developing device is replaced with a new toner cartridge to replenish the toner while the toner and external additives are contained in the developing device, toners in different states will be mixed. Therefore, Patent Document 1 describes a configuration in which an external additive having the same composition as the toner filled in the process cartridge is blended in the toner cartridge. Patent Document 1 also proposes a configuration in which the BET specific surface area of ​​the toner filled in the toner cartridge is made smaller than that of the toner filled in the process cartridge. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-83186 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the configuration of Patent Document 1 has the following problems: In the configuration of Patent Document 1, when, for example, multiple external additives are added to the toner used in image formation, image defects may occur when the toner cartridge is replaced with a new toner cartridge after use.

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to suppress image defects caused by developer replenishment in a configuration in which a replenishment container containing developer to be replenished to the developing device can be attached to the developing device. [Means for solving the problem]

[0008] In order to achieve the above object, an image forming apparatus according to the present invention has a rotatable image carrier, a charging member which charges the surface of the image carrier, and a developing unit which supplies a developer to the surface of the image carrier charged by the charging member to form a developer image, the developing unit including a rotatable developing member which carries the developer on its surface and a storage section which stores the developer to be supplied to the developing member, and a supply container which is detachable from the developing unit and stores a supply developer as the developer and is capable of supplying the supply developer to the storage section of the developing unit, and the storage section of the new developing unit is pre-filled with a predetermined amount of initial developer which is the developer. The initial developer and the replenishment developer contain at least toner particles and a first external additive and a second external additive, and the amount of the first external additive contained in the initial developer is defined as I1, the amount of the first external additive contained in the replenishment developer is defined as H1, the amount of the second external additive contained in the initial developer is defined as I2, and the amount of the second external additive contained in the replenishment developer is defined as H2, and the coverage of the first external additive in the initial developer, which are measured by ESCA, is defined as Wpa, the coverage of the first external additive in the replenishment developer is defined as Wta, the coverage of the second external additive in the initial developer is defined as Wpb, and the coverage of the second external additive in the replenishment developer is defined as Wtb, the coverage of the first external additive in the initial developer is defined as 0.9 Effect of the Invention

[0009] According to the present invention, in a configuration in which a supply container that contains developer to be replenished to a developing device can be attached to the developing device, image defects caused by developer replenishment can be suppressed. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a process cartridge and a toner cartridge according to the first embodiment. [Diagram 3] ​FIG. 2 is a schematic block diagram of a control configuration of the image forming apparatus according to the first embodiment. [Figure 4] 1 is a schematic diagram of a toner according to a first embodiment. [Diagram 5] 4 is a schematic transition of a coverage rate of an external additive A in a process cartridge in Example 1. [Figure 6] 4 is a schematic transition of a coverage rate of an external additive B in a process cartridge in Example 1. [Figure 7] 4 is a schematic transition of a coverage rate of an external additive A in a process cartridge in Example 1. [Figure 8] 4 is a schematic transition of a coverage rate of an external additive B in a process cartridge in Example 1. [Figure 9] FIG. 1 is a schematic diagram of a surface modification device in Example 1. [Figure 10] FIG. 11 is a schematic block diagram of a control configuration of an image forming apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The image forming apparatus and the supply container according to the present invention will be described in more detail below with reference to the drawings. However, the dimensions, materials, shapes, relative positions, voltage, speed, density, and other characteristics of the components described in the embodiments are merely examples for the purpose of explanation, and may be changed as appropriate depending on the configuration of the apparatus to which the invention is applied and various conditions. The scope of the invention is not limited to the following embodiments. EXAMPLES

[0012] <Overall configuration and operation of the image forming apparatus> 1 is a schematic cross-sectional view of an image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 according to the present embodiment is a monochrome laser printer capable of forming a black monochrome image on a sheet-shaped recording material P by using an electrophotographic method.

[0013] In this embodiment, the process cartridge 10 is mounted in the image forming apparatus 100 so as to be detachable from the apparatus main body 110. The process cartridge 10 can be easily attached to and detached from the apparatus main body 110 via mounting means (not shown) such as a mounting guide and a positioning member provided on the apparatus main body 110 and the process cartridge 10. In this embodiment, the toner cartridge 9 is mounted as a toner supply container (developer supply container) in the image forming apparatus 100 so as to be detachable from the apparatus main body 110 and the process cartridge 10. The toner cartridge 9 can be easily attached to and detached from the apparatus main body 110 and the process cartridge 10 via mounting means (not shown) such as a mounting guide and a positioning member provided on the apparatus main body 110, the process cartridge 10, and the toner cartridge 9. The apparatus main body 110 is a component of the image forming apparatus 100 excluding the process cartridge 10 and the toner cartridge 9. The toner cartridge 9 and the process cartridge 10 are each detached from the apparatus main body 110 by opening a top cover 111 that is openably provided on the top of the apparatus main body 110 .

[0014] The process cartridge 10 has a photosensitive drum 1, which is a rotatable drum-type (cylindrical) photosensitive member (electrophotographic photosensitive member) serving as an image carrier, and a charging roller 2, which is a roller-type charging member serving as a charging means (charging device). The process cartridge 10 also has a developing device 4 serving as a developing means, and a cleaning device 6 serving as a cleaning means.

[0015] Above the process cartridge 10 in the apparatus main body 110, an exposure device (scanner unit) 3 is provided as an exposure means.

[0016] During an image forming operation, the photosensitive drum 1 is rotated in the direction of the arrow R1 in the figure (clockwise direction) at a predetermined process speed (circumferential speed). The surface of the rotating photosensitive drum 1 is uniformly charged to a predetermined potential of a predetermined polarity (negative polarity in this embodiment) by the charging roller 2. During charging, a predetermined charging voltage (charging bias) is applied to the charging roller 2. The charged surface of the photosensitive drum 1 is selectively exposed (scanning exposed) by the exposure device 3 in accordance with image information (image signal), and an electrostatic latent image (electrostatic image) corresponding to the image information is formed on the photosensitive drum 1. The electrostatic latent image formed on the photosensitive drum 1 is developed (visualized) by the developing device 4 by supplying toner as a developer, and a toner image (toner image, developer image) corresponding to the image information is formed on the photosensitive drum 1. During development, a predetermined developing voltage (developing bias) is applied to the developing roller 43 provided in the developing device 4. In this embodiment, toner charged with the same polarity as the charge polarity of the photosensitive drum 1 (negative polarity in this embodiment) adheres to an exposed portion (image portion) on the photosensitive drum 1, the absolute value of the potential of which has been reduced by exposure after being uniformly charged (reversal development method). In this embodiment, the regular charge polarity (regular polarity), which is the main charge polarity of the toner during development, more specifically, the toner particles 45a (FIG. 4) described later, is negative polarity.

[0017] Opposing the photosensitive drum 1, a transfer roller 5, which is a roller-type transfer member serving as a transfer means, is disposed. The transfer roller 5 is pressed against the photosensitive drum 1 to form a transfer portion (transfer position, transfer nip) Nt, which is a contact portion between the photosensitive drum 1 and the transfer roller 5. The toner image formed on the photosensitive drum 1 is transferred to a recording material P, which is a transfer target material, being sandwiched and conveyed between the photosensitive drum 1 and the transfer roller 5 at the transfer portion Nt. A transfer power source (high voltage power source) (not shown) is connected to the transfer roller 5 as a transfer voltage application means provided in the device main body 110. During transfer, a predetermined transfer voltage (transfer bias), which is a DC voltage of a polarity opposite to the normal charging polarity of the toner, more specifically, the toner particles 45a (positive polarity in this embodiment), is applied to the transfer roller 5 from the transfer power source. A recording material (transfer material, recording medium, sheet) P, such as recording paper, an OHP sheet, or a cloth, is fed from the feeding portion 20 toward the transfer portion Nt.

[0018] The feeding section 20 is configured to have a cassette 21 as a recording material storage section, a feeding roller 22 as a feeding member, and the like. The recording material P stored in the cassette 21 is separated one by one by the feeding roller 22 and sent out from the cassette 21. The recording material P is transported to the transfer section Nt by a registration roller 30 as a transport member in synchronization with the toner image on the photosensitive drum 1.

[0019] The recording material P onto which the toner image has been transferred is transported to a fixing device 7 serving as a fixing means. The fixing device 7 applies heat and pressure to the recording material P carrying the unfixed toner image, thereby fixing (melting and bonding) the toner image onto the recording material P. The recording material P onto which the toner image has been fixed is discharged (output) by a discharge roller 8 serving as a transport member or the like onto a tray 50 serving as a discharge section provided at the top of the apparatus main body 110.

[0020] On the other hand, toner (transfer residual toner) remaining on the photosensitive drum 1 without being transferred onto the recording material P during transfer is removed from the photosensitive drum 1 by a cleaning device 6 and collected.

[0021] <Process cartridge> Next, the process cartridge 10 in this embodiment will be further described. Fig. 2 is a schematic cross-sectional view of the process cartridge 10 in this embodiment. Note that Fig. 2 also shows the toner cartridge 9.

[0022] The process cartridge 10 has a drum unit (photosensitive unit) 11 and a developing device (developing unit) 4. The drum unit 11 and the developing device 4 are connected to each other to form the process cartridge 10 which is detachably attached to the main body 110 of the apparatus.

[0023] The drum unit 11 includes a photosensitive drum 1, a charging roller 2, and a cleaning device 6. The photosensitive drum 1 is rotatably attached to a drum unit frame 11a.

[0024] A charging roller 2 and a cleaning member 63 of a cleaning device 6 are in contact with the surface (outer circumferential surface) of the photosensitive drum 1. The photosensitive drum 1 is rotationally driven at a predetermined process speed (circumferential speed) in the direction of arrow R1 in the figure (clockwise direction) by a driving force transmitted from a driving motor (not shown) serving as a driving source constituting a driving means provided in the apparatus main body 110.

[0025] The cleaning device 6 has a cleaning container (cleaning frame) 61 that constitutes a part of the drum unit frame 11a. The cleaning container 61 has a removed toner chamber 62 formed therein for accommodating the transfer residual toner removed from the photosensitive drum 1. A cleaning member 63 is attached to the cleaning container 61. The cleaning member (cleaning blade) 63 is configured to have a rubber blade, which is a plate-shaped member formed of rubber as an elastic member, and a cleaning support member that supports the rubber blade. The rubber blade is a plate-shaped member that has a predetermined length and a predetermined thickness in a longitudinal direction disposed approximately parallel to the rotation axis direction of the photosensitive drum 1 and a lateral direction approximately perpendicular to the longitudinal direction. The cleaning member 63 is disposed in contact with the surface of the photosensitive drum 1 so that the rubber blade is in a counter direction to the rotation direction of the photosensitive drum 1 (the tip end in the lateral direction faces the upstream side of the rotation direction of the photosensitive drum 1). The cleaning device 6 scrapes off the residual toner from the surface of the rotating photosensitive drum 1 with a cleaning member 63 and drops it into a removed toner chamber 62 for collection. A scooping sheet 64 is attached to the cleaning container 61 to prevent the toner in the removed toner chamber 62 from leaking. The scooping sheet 64 is disposed in contact with the surface of the photosensitive drum 1 upstream of the cleaning member 63 in the rotation direction of the photosensitive drum 1.

[0026] The charging roller 2 is rotatably attached to the drum unit frame 11a. The charging roller 2 is disposed in contact with the surface of the photosensitive drum 1, is pressed toward the photosensitive drum 1 by a pressure member (not shown), and rotates in accordance with the rotation of the photosensitive drum 1. During charging, a predetermined charging voltage (charging bias) is applied to the charging roller 2 from a charging power source (high voltage power source) (not shown) as a charging voltage application means provided in the device main body 110. As a result, a uniform dark area potential (Vd) is formed on the surface of the photosensitive drum 1. Then, the surface of the photosensitive drum 1 is exposed to a spot pattern of laser light emitted from the exposure device 3 in response to image data. The exposed portion of the surface of the photosensitive drum 1 loses surface charge due to carriers from the carrier generation layer, and the absolute value of the potential decreases. As a result, an electrostatic latent image is formed on the photosensitive drum 1, in which the exposed portion has a predetermined light area potential (Vl) and the unexposed portion has a predetermined dark area potential (Vd). In this embodiment, Vd=-500V and Vl=-100V.

[0027] On the other hand, the developing device (developing unit) 4 has a developing container (developing frame) 41. The developing container 41 has a toner storage chamber 42 formed therein as a storage section for storing toner T. In this embodiment, the toner storage chamber 42 stores a non-magnetic one-component developer (toner) T as a developer. A developing roller 43 as a developer carrier (developing member) and a supply roller 44 as a supply member are rotatably attached to the developing container 41. The developing roller 43 carries and transports the toner T, and supplies the toner T to the photosensitive drum 1 in accordance with the electrostatic latent image on the photosensitive drum 1. The supply roller 44 supplies the toner T to the developing roller 43. In addition, a developing blade 46 as a regulating member is attached to the developing container 41. The developing blade 46 regulates the toner amount of the toner layer on the developing roller 43 and frictionally charges the toner T. In addition, a blowout prevention sheet 49 is attached to the developing container 41.

[0028] Furthermore, a stirring member 47 is rotatably attached to the developing container 41 .

[0029] The developing roller 43 is disposed in contact with the surface of the photosensitive drum 1, and is rotationally driven in the direction of the arrow R2 in the figure (counterclockwise direction) by a driving force transmitted from a driving motor (not shown) as a driving source constituting a driving means provided in the main body 110 of the apparatus. The supply roller 44 is disposed in contact with the developing roller 43, and is rotationally driven in the direction of the arrow R3 in the figure (counterclockwise direction) by a driving force transmitted from a driving motor (not shown) as a driving source constituting a driving means provided in the main body 110 of the apparatus. The developing blade 46 is a plate-shaped member having a predetermined length in the longitudinal direction disposed approximately parallel to the rotation axis direction of the developing roller 43 and in the lateral direction approximately perpendicular to the longitudinal direction, and having a predetermined thickness. The developing blade 46 is formed of a conductive metal as an elastic member. The developing blade 46 is positioned so that its free end in the short side direction faces upstream in the direction of rotation of the developing roller 43 and the surface facing the developing roller 43 near the free end abuts against the developing roller 43.

[0030] When the toner T supplied to the developing roller 43 by the supply roller 44 passes through the contact portion between the developing blade 46 and the developing roller 43, the amount of toner T on the developing roller 43 (toner coat amount) is regulated and the toner T is frictionally charged. As a result, a toner coat suitable for developing the electrostatic latent image formed on the photosensitive drum 1 is formed on the developing roller 43. The developing roller 43 and the photosensitive drum 1 each rotate such that their surfaces move in the same direction (from top to bottom in this embodiment) at the developing portion, which is the opposing portion (contact portion) between the developing roller 43 and the photosensitive drum 1.

[0031] In this embodiment, during development, the developing roller 43, the supply roller 44, and the developing blade 46 are applied with independent voltages from a high-voltage power source (not shown). That is, a predetermined developing voltage (developing bias) is applied to the developing roller 43 from a developing power source (not shown) serving as a developing voltage application means provided in the main body 110 of the apparatus. A predetermined supply voltage (supply bias) is applied to the supply roller 44 from a supply power source (not shown) serving as a supply voltage application means provided in the main body 110 of the apparatus. A predetermined regulated voltage (regulated bias) is applied to the developing blade 46 from a regulated power source (not shown) serving as a regulated voltage application means provided in the main body 110 of the apparatus. In this embodiment, during development, a predetermined developing voltage is applied to the developing roller 43, which is a direct current voltage (DC bias) having the same polarity (negative polarity in this embodiment) as the normal charging polarity of the toner, more specifically, the toner particles 45a. In addition, in this embodiment, during development, a predetermined supply voltage is applied to the supply roller 44, which is a direct current voltage (DC bias) having the same polarity (negative in this embodiment) as the normal charging polarity of the toner, more specifically, the toner particles 45a, and whose absolute value is greater than that of the developing voltage. In this embodiment, during development, a predetermined regulated voltage is applied to the development blade 46, which is a direct current voltage (DC bias) having the same polarity (negative in this embodiment) as the normal charging polarity of the toner, more specifically, the toner particles 45a, and whose absolute value is greater than that of the developing voltage. The toner T supplied to the development roller 43 by the supply roller 44 is triboelectrically charged by friction between the development roller 43 and the development blade 46, and is charged and its layer thickness is regulated at the same time. The toner T on the development roller 43, whose layer thickness has been regulated, is transported to a development section, which is an opposing portion (contact portion) between the photosensitive drum 1 and the development roller 43, by the rotation of the development roller 43. Then, in the developing portion, the toner T on the developing roller 43 is transferred to the light potential portion on the photosensitive drum 1 due to the potential difference between the image portion (light potential portion) of the electrostatic latent image on the photosensitive drum 1 and the developing voltage. This causes the electrostatic latent image on the photosensitive drum 1 to be developed (visualized). In this embodiment, the developing voltage (Vdc) applied to the developing roller 43 is -300V. Also, in this embodiment, the supply voltage applied to the supply roller 44 and the regulated voltage applied to the developing blade 46 are each -400V.This creates a potential difference between the developing roller 43 and the supply roller 44, and between the developing roller 43 and the developing blade 46, which makes it easier for the negatively charged toner T to be supplied to the developing roller 43.

[0032] Further, the blowout prevention sheet 49 is disposed in contact with the developing roller 43 to prevent the toner T from leaking from the developing container 41.

[0033] The stirring member 47 is disposed in the toner-accommodating chamber 42, and stirs the toner T accommodated in the toner-accommodating chamber 42 and transports the toner T toward the supply roller 44.

[0034] The stirring member 47 includes a stirring shaft 47a rotatably attached to the developing container 41, and a sheet member 47b attached to the stirring shaft 47a and rotating together with the stirring shaft 47a. The stirring shaft 47a of the stirring member 47 is rotated by a driving force transmitted from a driving motor (not shown) serving as a driving source constituting a driving means provided in the main body 110 of the apparatus.

[0035] The photosensitive drum 1 and each of the rotating members (the developing roller 43, the supply roller 44, and the stirring member 47) of the developing device 4 may share a driving source.

[0036] In this embodiment, the process cartridge 10 is provided with a process cartridge memory MP (hereinafter, simply referred to as "memory MP"), which is a non-volatile storage means (storage medium), as shown in FIG. 2. The memory MP stores usage information (information relating to usage history) and lifespan information (information relating to replacement time) of the developing device 4 (process cartridge 10). The memory MP may further store usage information (information relating to usage history) and lifespan information (information relating to replacement time) of the toner cartridge 9. The memory MP functions as a memory tag for grasping information relating to the developing device 4 (process cartridge 10) and the toner cartridge 9 on the apparatus main body 110 side.

[0037] Here, the toner storage chamber 42 of the developer container 41 of a new (unused, at the start of use) developing device 4 (process cartridge 10) is filled in advance with a predetermined amount of toner T. In this embodiment, the predetermined amount of toner T filled in advance in the new developing device 4 (process cartridge 10) is 150 g.

[0038] <Toner cartridge> Next, the toner cartridge 9 in this embodiment will be further described.

[0039] As shown in FIGS. 1 and 2, a toner cartridge 9 serving as a toner supply container (developer supply container) is disposed above the process cartridge 10. The toner cartridge 9 is configured to be detachable from the apparatus main body 110 and the process cartridge 10. The toner cartridge 9 has a supply toner chamber 92 formed therein for accommodating replenishment toner T. A predetermined amount of toner T' is accommodated in the supply toner chamber 92 of a new (unused, at the start of use) toner cartridge 9. In this embodiment, the predetermined amount of toner T' accommodated in a new toner cartridge 9 is 600 g.

[0040] The toner cartridge 9 has a toner discharging device (toner discharging mechanism) 91 as a toner discharging means that discharges the toner T' from the toner cartridge 9 toward the developing device 4. In this embodiment, the toner discharging device 91 discharges the toner T' accommodated in a supply toner chamber 92 of the toner cartridge 9 downward, and supplies the toner to the developing device 4.

[0041] In this embodiment, the toner discharge device 91 employs a variable volume pump system. The toner discharge device 91 operates by transmitting a driving force from a driving motor (not shown) as a driving source constituting a driving means provided in the main body 110 of the apparatus through a clutch 70 (FIG. 3) as a driving coupling portion provided in the main body 110 of the apparatus. That is, the toner discharge device 91 is driven and coupled by the clutch 70 at a desired timing for a desired time, so that a variable volume pump operates and discharges a desired amount of toner T' from the toner cartridge 9. The toner T' discharged from the toner cartridge 9 is transported to the inside of the toner storage chamber 42 of the developer container 41 through a communication port (supply port) 48 provided in the developer container 41, and is replenished to the developing device 4. The toner T' replenished to the developing device 4 is stirred by the stirring member 47 in the toner storage chamber 42 of the developer container 41.

[0042] In this embodiment, the toner consumed from the developing device 4 is successively replenished from the toner cartridge 9 to the developing device 4. In this embodiment, in a state in which the toner can be sufficiently replenished from the toner cartridge 9 to the developing device 4 in the amount of toner consumed from the developing device 4, the amount of toner in the developing device 4 is maintained substantially constant at a predetermined amount of the toner T pre-filled in the new developing device 4. The above-mentioned state in which the toner can be sufficiently replenished is, for example, from the start of use of the toner cartridge 9 until the toner T' in the toner cartridge 9 runs out (or until the amount of toner T' that can be replenished to the developing device 4 per unit time decreases to a predetermined amount). That is, in this embodiment, the amount of toner consumed by the developing device 4 and the amount of toner replenished from the toner cartridge 9 to the developing device 4 are substantially equal. Note that a difference may occur between the amount of toner consumed by the developing device 4 and the amount of toner replenished from the toner cartridge 9 to the developing device 4 during an image forming operation. In such a case, the toner discharge operation can be adjusted so that the amount of toner in the developing device 4 is maintained substantially constant, for example, at the end of an image forming operation or the start of a subsequent image forming operation. For example, if the amount of toner replenished becomes less than the amount of toner consumed during an image forming operation, the toner discharging operation can be continued until the amount of toner in the developing device 4 reaches a predetermined amount, such as at the end of the image forming operation. Also, for example, if the amount of toner replenished becomes greater than the amount of toner consumed during an image forming operation, the toner discharging operation can be stopped until the amount of toner in the developing device 4 reaches a predetermined amount, such as at the start of the subsequent image forming operation.

[0043] The toner discharge device 91 is not limited to a variable volume pump type. For example, any configuration may be used as long as it can discharge a desired amount of toner at a desired timing, such as a toner discharge screw as a conveying member.

[0044] In this embodiment, the toner cartridge 9 is provided with a toner cartridge memory MT (hereinafter, simply referred to as "memory MT"), which is a non-volatile storage means (storage medium), as shown in Fig. 2. The memory MT stores usage information (information relating to usage history) and lifespan information (information relating to replacement time) of the toner cartridge 9. The toner cartridge memory MT functions as a memory tag for the apparatus main body 110 to grasp information relating to the toner cartridge 9.

[0045] <Control configuration> 3 is a schematic block diagram showing a control configuration of the main parts of the image forming apparatus 100 of this embodiment. The apparatus body 110 of the image forming apparatus 100 is provided with a control unit 120 as a control means. The control unit 120 is configured to include a CPU 121 as a calculation processing means which is a central element for performing calculation processing, a ROM 122 and a RAM 123 as storage means (storage media), an input / output circuit (not shown), and the like. The ROM 122 stores a control program, a data table obtained in advance, and the like. The RAM 123 stores information input to the control unit 120, detected information, calculation results, and the like. The input / output circuit controls input / output of signals between the control unit 120 and devices connected thereto.

[0046] The control unit 120 is connected to each part of the image forming apparatus 100 (such as various driving devices, various power sources, and various sensors). The control unit 120 communicates bidirectionally with each part of the image forming apparatus 100 to control the operation of each part. The control unit 120 controls each part of the image forming apparatus 100 to perform an image forming operation based on signals (start signal, image signal) input from an external device (not shown) such as a personal computer in response to an operation by an operator such as a user or a service person.

[0047] Furthermore, the control unit 120 controls the clutch 70, which switches between transmitting and releasing the driving force to the toner discharge device 91 of the toner cartridge 9, to control the supply of toner from the toner discharge device 91 to the developing device 4. Furthermore, in this embodiment, the control unit 120 is capable of calculating the amount of toner in the developing device 4 and the amount of toner in the toner cartridge 9 by measuring the time during which the clutch 70 is ON, as will be described later.

[0048] In addition, the control unit 120 is connected to an image processing unit (video controller) 130 that generates image information used for image formation in the image forming apparatus 100 based on a signal input from an external device. In this embodiment, the control unit 120 is capable of counting the number of pixels of the image information acquired from the image processing unit 130 and calculating the amount of toner in the developing device 4, as will be described later.

[0049] Furthermore, the control unit 120 reads and writes information from and to the memory MP and memory MT. An operation panel OP serving as an operation unit provided in the device body 110 is connected to the control unit 120. The operation panel OP is configured to include a display unit for displaying information to an operator under the control of the control unit 120, an input unit for inputting information to the control unit 120 in response to an operation by the operator, and the like.

[0050] <Detecting the amount of toner in the developing device> The amount of toner (remaining toner) in the developing device 4 can be calculated, for example, by the control unit 120 as a detection means based on the amount of toner consumed by the developing device 4, the amount of toner supplied from the toner cartridge 9 to the developing device 4, and the initial (new, unused) amount of toner in the developing device 4.

[0051] The toner consumption amount of the developing device 4 can be calculated as follows. That is, the toner consumption amount associated with image formation (development) can be calculated by counting the number of pixels of the image information and based on the relationship between the number of pixels and the toner consumption amount obtained in advance (pixel count method, video count method). In addition, the toner consumption amount due to toner consumption operations other than image formation (fog during non-image formation, adjustment operations, etc.) can be calculated from the toner consumption amount obtained in advance for each toner consumption operation other than image formation.

[0052] Furthermore, the amount of toner replenished from the toner cartridge 9 to the developing device 4 can be calculated based on the time taken for the operation of discharging the toner T' from the toner cartridge 9 (toner discharging operation) (replenishment time measurement method). For example, the time (toner discharging operation time) during which the clutch 70 for drivingly connecting to the toner discharging device 91 of the toner cartridge 9 is ON (driving force transmission state) is measured. Then, the amount of toner replenished can be calculated based on the relationship between the toner discharging operation time and the toner discharge amount obtained in advance.

[0053] Then, the amount of toner (remaining amount of toner) in the developing device 4 can be calculated successively based on the amount of toner initially filled in the developing device 4, the amount of toner consumed by the developing device 4, and the amount of toner supplied from the toner cartridge 9 to the developing device 4. Specifically, the amount of toner in the developing device 4 can be calculated successively by subtracting the amount of toner consumed by the developing device 4 from the amount of toner supplied from the toner cartridge 9 to the developing device 4.

[0054] In addition, the amount of toner in the developing device 4 can be calculated more accurately by correcting based on the detection result by another detection means that detects the amount of toner in the developing device 4. For example, by using a weight detection type detection means that detects the weight of the developing device 4, the amount of toner in the developing device 4 can be corrected at an appropriate timing. Similarly, it is possible to use any detection method, such as an optical detection method, a capacitance method, or a toner surface detection method. For example, during the image forming operation, the amount of toner in the developing device 4 can be detected by the above-mentioned method, and correction can be performed based on the detection result by the other detection means at the end of the image forming operation. Note that the above-mentioned detection methods may be used in any combination, or each may be used alone.

[0055] The weight detection method is a method for detecting the amount of toner in the developing container 41 based on the weight of the developing container 41 containing the toner. The optical detection method is a method for detecting the amount of toner based on the change in the light receiving state of the light receiving unit using a light source that irradiates light into the inside of the developing container 41 and a light receiving unit that receives the light that has passed through the inside of the developing container 41. The capacitance method is a method for detecting the amount of toner in the developing container 41 based on the change in the detected capacitance using an electrode whose capacitance changes according to the change in the state of the toner in the developing container 41 (for example, by attaching a conductive member to the inner wall of the container). The agent surface detection method is a method for detecting the amount of toner in the developing container 41 based on the position (height) of the agent surface of the toner in the developing container 41. Instead of the method based on image information described above, the amount of toner in the developing device 4 can also be detected by using the above-mentioned other detection means alone or in any combination.

[0056] The usage history values ​​of the developing device 4 (toner consumption amount, toner supply amount, remaining toner amount) are stored in the memory MP.

[0057] <Detecting the amount of toner in a toner cartridge> The amount of toner (remaining toner) in the toner cartridge 9 can be calculated, for example, by the control unit 120, which serves as a detection means, based on the amount of toner supplied from the toner cartridge 9 to the developing device 4 and the amount of toner in an initial (new, unused) toner cartridge 9.

[0058] The amount of toner replenishment can be calculated by measuring the time (toner discharge operation time) that the clutch 70 for drivingly connecting to the toner discharge device 91 is ON, and based on the relationship between the toner discharge operation time and the toner discharge amount that has been determined in advance.

[0059] Then, the amount of toner in the toner cartridge 9 (remaining toner amount) can be calculated successively based on the amount of toner initially filled in the toner cartridge 9 and the amount of toner supplied from the toner cartridge 9 to the developing device 4. Specifically, the amount of toner in the toner cartridge 9 can be calculated successively by subtracting the amount of toner initially filled in the toner cartridge 9 from the amount of toner supplied from the toner cartridge 9 to the developing device 4.

[0060] In this embodiment, the amount of toner supply is calculated based on the time when the clutch 70 is ON, that is, the operation time of the pump constituting the toner discharge device 91, but the present invention is not limited to this. For example, if the toner discharge device 91 is configured with a toner discharge screw, the amount of toner supply may be calculated based on the total number of rotations of the toner discharge screw. As with the above-mentioned means for detecting the amount of toner in the developing device 4, any detection method may be used, such as an optical detection method, a capacitance method, a toner level detection method, or a weight detection method. The above-mentioned detection methods may be used in any combination or each may be used alone.

[0061] The toner cartridge 9 reaches the time to be replaced when the toner contained therein has decreased to a predetermined amount (typically when almost all of the toner contained therein has been discharged toward the developing device 4). In other words, the toner cartridge 9 needs to be replaced when the amount of toner in the toner cartridge 9 has decreased to a predetermined amount and it has reached a state where the toner cartridge 9 cannot sufficiently replenish the toner to the developing device 4 to replace the amount consumed by the developing device 4. Specifically, the amount of toner remaining in a new toner cartridge 9 can be set to 100%, and a state where the amount of toner remaining in the toner cartridge 9 has decreased to a predetermined threshold value can be set to 0%.

[0062] In this embodiment, 0% toner remaining corresponds to a state in which the toner in the toner cartridge 9 has been substantially completely discharged. However, a state in which a small amount of toner remains in the toner cartridge 9 may also be regarded as a 0% toner remaining (toner out) state.

[0063] The usage history values ​​(amount of toner supplied, amount of toner remaining) of the toner cartridge 9 are stored in memory MT. The usage history values ​​(amount of toner supplied, amount of toner remaining) of the toner cartridge 9 may be further stored in memory MP. In this embodiment, the control unit 120 executes a process to notify the operator that the toner cartridge 9 is out of toner when the amount of toner remaining indicated by the usage history value of the toner cartridge 9 reaches a predetermined threshold value.

[0064] The control unit 120 can notify the operator of the above-mentioned information by displaying the information on the display unit of the operation panel OP. The notification of information to the operator is not limited to a display of a message on the display unit. For example, the notification may be by a warning sound or voice from a sound generating unit, or by lighting or blinking of a light emitting unit. Instead of or in addition to the notification of information to the operator on the operation panel OP, the information may be notified to the operator from an external device communicably connected to the image forming apparatus 100.

[0065] Based on the notification, the operator can remove the used toner cartridge 9 from the developing device 4 (process cartridge 10) and mount a new toner cartridge 9 in the developing device 4 (process cartridge 10).

[0066] Furthermore, the control unit 120 may be configured to separately count the number of times the toner cartridge 9 is replaced for one developing device 4 (process cartridge 10) and determine and notify the replacement time (life) of the developing device 4 (process cartridge 10). The replacement time (life) of the developing device 4 (process cartridge 10) may be set based on an index value (e.g., the number of rotations or the rotation time) of the usage amount of the developing roller 43 in the developing device 4 or an index value (e.g., the number of rotations or the rotation time) of the usage amount of the photosensitive drum 1. When the process cartridge 10 reaches the replacement time, the operator can remove the used process cartridge 10 from the apparatus main body 110 and mount a new process cartridge 10 in the apparatus main body 110.

[0067] In the present embodiment, the toner consumed from the developing device 4 is successively replenished to the developing device 4, but the toner may be periodically replenished, for example, when the amount of toner in the developing device 4 decreases to a predetermined amount or when a predetermined amount of toner is consumed from the developing device 4. Also, as the toner cartridge 9, a bulk toner replenishment system using a toner pack or piston that can replenish toner from the toner cartridge 9 to the developing device 4 in a lump may be adopted. In the bulk toner replenishment system, the image forming apparatus 100 may be capable of removing the toner cartridge 9 as a replenishment container from the image forming apparatus 100 and using it.

[0068] <Photoreceptor> Next, the photoconductor (photoconductor drum 1) used in this embodiment will be further described.

[0069] The photoreceptor used in this embodiment is configured such that an undercoat layer is formed on a support, a charge generating layer is formed on the undercoat layer, a charge transport layer is formed on the charge generating layer, and a protective layer is formed on the charge transport layer. The protective layer is preferably the outermost layer of the photoreceptor.

[0070] The photoreceptor can be manufactured by preparing a coating solution for each layer described below, coating the layers in the desired order, and drying the coating solution. Examples of the coating method include dip coating, spray coating, wire bar coating, and ring coating. Among these, dip coating is preferred from the viewpoints of efficiency and productivity.

[0071] (Support) The support is preferably a conductive support having electrical conductivity. The shape of the support may be cylindrical, belt-like, or sheet-like. In this embodiment, a cylindrical support is used. The surface of the support may be subjected to electrochemical treatment such as anodization, blasting, cutting, or the like. The material of the support is preferably metal, resin, glass, or the like. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support using aluminum is preferable in terms of cost and ease of processing. In addition, in the case of resin or glass, electrical conductivity may be imparted by a treatment such as mixing or coating a conductive material.

[0072] A conductive layer may be provided on the support. By providing the conductive layer, scratches and unevenness on the surface of the support can be concealed and light reflection on the surface of the support can be controlled. The conductive layer preferably contains conductive particles and a resin. Examples of materials for the conductive particles include metal oxides, metals, and carbon black.

[0073] Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Among these, it is preferable to use metal oxides as the conductive particles, and it is more preferable to use titanium oxide, tin oxide, and zinc oxide. When using metal oxides as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as phosphorus or aluminum or its oxide. The conductive particles may also have a laminated structure having a core particle and a coating layer that coats the particle. Examples of the core particle include titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include metal oxides such as tin oxide. When using metal oxides as the conductive particles, the volume average particle diameter is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0074] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin.

[0075] The conductive layer may further contain silicone oil, resin particles, a masking agent such as titanium oxide, and the like.

[0076] The average thickness of the conductive layer is preferably from 1 μm to 50 μm, and particularly preferably from 3 μm to 40 μm.

[0077] The conductive layer can be formed by preparing a coating solution for the conductive layer containing the above-mentioned materials and solvent, forming a coating film using this coating solution, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of the dispersion method for dispersing the conductive particles in the coating solution for the conductive layer include a method using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser.

[0078] (Undercoat layer) An undercoat layer is provided on the support or the conductive layer. By providing the undercoat layer, the adhesion function between the support or the conductive layer and the layer thereon can be improved, and a charge injection blocking function can be imparted to the photoreceptor.

[0079] The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

[0080] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl phenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, and cellulose resin.

[0081] Examples of the polymerizable functional group contained in the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, a carboxylic anhydride group, and a carbon-carbon double bond group.

[0082] For the purpose of improving electrical properties, the undercoat layer may further contain an electron transporting material, a metal oxide, a metal, a conductive polymer, etc. Among these, it is preferable to use an electron transporting material or a metal oxide.

[0083] Examples of the electron transport substance include a quinone compound, an imide compound, a benzimidazole compound, a cyclopentadienylidene compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, an aryl halide compound, a silole compound, a boron-containing compound, etc. An electron transport substance having a polymerizable functional group may be used as the electron transport substance, and the undercoat layer may be formed as a cured film by copolymerizing the electron transport substance with the monomer having the polymerizable functional group described above.

[0084] Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide, etc. Examples of metals include gold, silver, aluminum, etc.

[0085] The undercoat layer may further contain an additive.

[0086] The average thickness of the undercoat layer is preferably from 0.1 μm to 50 μm, more preferably from 0.2 μm to 40 μm, and particularly preferably from 0.3 μm to 30 μm.

[0087] The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0088] (Charge generation layer) The charge generating layer preferably contains a charge generating material and a resin. Examples of the charge generating material include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred.

[0089] The content of the charge generating material in the charge generating layer is preferably from 40% by mass to 85% by mass, and more preferably from 60% by mass to 80% by mass, based on the total mass of the charge generating layer.

[0090] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, polyvinyl chloride resin, etc. Among these, polyvinyl butyral resin is more preferable.

[0091] The charge generating layer may further contain additives such as an antioxidant and an ultraviolet absorbing agent.

[0092] Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0093] The average thickness of the charge generating layer is preferably from 0.1 μm to 1 μm, and more preferably from 0.15 μm to 0.4 μm.

[0094] The charge generating layer can be formed by preparing a coating liquid for the charge generating layer containing the above-mentioned materials and solvent, forming a coating film from the coating liquid, and drying the coating liquid. Examples of the solvent used in the coating liquid include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0095] (charge transport layer) The charge transport layer preferably contains a charge transport material and a resin. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred.

[0096] The content of the charge transport material in the charge transport layer is preferably from 25% by weight to 70% by weight, and more preferably from 30% by weight to 55% by weight, based on the total weight of the charge transport layer.

[0097] Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, etc. Among these, polycarbonate resin and polyester resin are preferable. As the polyester resin, polyarylate resin is particularly preferable.

[0098] The content ratio (mass ratio) of the charge transport material to the resin is preferably from 4:10 to 20:10, and more preferably from 5:10 to 12:10.

[0099] The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, and abrasion resistance improvers. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0100] The average thickness of the charge transport layer is preferably 5 μm to 50 μm, more preferably 8 μm to 40 μm, and particularly preferably 10 μm to 30 μm In this embodiment, the average thickness of the charge transport layer is 12 μm.

[0101] The charge transport layer can be formed by preparing a coating liquid for the charge transport layer containing the above-mentioned materials and solvent, forming a coating film from the coating liquid, and drying it. Examples of the solvent used in the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents or aromatic hydrocarbon-based solvents are preferred.

[0102] In this embodiment, a laminated type photoreceptor having a charge generating layer and a charge transporting layer is used, but a single-layered type photoreceptor containing both a charge generating material and a charge transporting material may be used. The single-layered type photoreceptor can be formed by preparing a coating liquid for a photosensitive layer containing a charge generating material, a charge transporting material, a resin, and a solvent, forming a coating film from this coating liquid, and drying it. The charge generating material, the charge transporting material, and the resin are the same as the examples of materials for the laminated type photoreceptor.

[0103] (protective layer) The photoreceptor used in this embodiment has an abrasion-resistant protective layer on the outermost surface to improve abrasion resistance. By providing the protective layer, durability can be improved. The protective layer preferably contains conductive particles and / or a charge transport material, and a resin.

[0104] The conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0105] Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred.

[0106] Examples of the resin include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenol resin, melamine resin, epoxy resin, etc. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferable.

[0107] The protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the reaction include thermal polymerization, photopolymerization, and radiation polymerization. Examples of the polymerizable functional group of the monomer having a polymerizable functional group include an acrylic group and a methacrylic group. A material having a charge transport function may be used as the monomer having a polymerizable functional group.

[0108] The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, and abrasion resistance improvers. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0109] The average thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 7 μm or less In this embodiment, the average thickness of the protective layer is set to 3 μm.

[0110] The protective layer can be formed by preparing a coating solution for the protective layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0111] <Toner> Next, the toner T used in this embodiment will be further described. Fig. 4 is a schematic diagram of the toner T. First, the toner T (hereinafter, also referred to as "initial filling toner (or initial developer)") that is filled in advance in a new developing device 4 will be described.

[0112] In this embodiment, the toner T contains negatively charged toner particles 45a, silica particles 45b, and positively charged lubricant particles 45c. That is, in this embodiment, the toner T is configured by externally adding silica particles 45b for ensuring the fluidity and improving the chargeability of the toner T, and positively charged lubricant particles 45c to the negatively charged toner particles 45a. Here, "negative chargeability" and "positive chargeability" mean whether the particles are charged negatively (-) (whether the charge polarity is negative) or positively (+) (whether the charge polarity is positive) when they are charged in the developing device 4.

[0113] As will be described in detail later, the toner T' contained in the toner cartridge 9 (hereinafter also referred to as "supply toner (or supply developer)") has the same amount of positively charged lubricant particles 45c externally added to the toner particles 45a as the initially filled toner T, but has a different external addition strength (external addition conditions). In this embodiment, the other points of the replenishment toner T' are the same as those of the initially filled toner T.

[0114] (Toner particles) The toner particles 45a of the toner T used in this embodiment are a non-magnetic one-component particle-polymerized toner having a negative charge polarity, and a weight average particle size of 7 μm.

[0115] The toner particles 45a can be manufactured by a known kneading and grinding method or a wet manufacturing method. From the viewpoint of uniformity of particle size and shape controllability, the wet manufacturing method is preferably used. Further, examples of the wet manufacturing method include a suspension polymerization method, a dissolution suspension method, an emulsion polymerization aggregation method, and an emulsion aggregation method.

[0116] Here, the suspension polymerization method will be described. In the suspension polymerization method, first, a polymerizable monomer composition is prepared by uniformly dissolving or dispersing a polymerizable monomer for producing a binder resin, a colorant, and other additives as necessary, using a dispersing machine such as a ball mill or an ultrasonic dispersing machine (preparation process of a polymerizable monomer composition). At this time, a multifunctional monomer, a chain transfer agent, a wax as a release agent, a charge control agent, a plasticizer, and the like can be appropriately added as necessary.

[0117] Next, the polymerizable monomer composition is poured into a previously prepared aqueous medium, and droplets of the polymerizable monomer composition are formed into the desired size of toner particles 45a using a stirrer or disperser having high shear force (granulation process). It is preferable that the aqueous medium in the granulation process contains a dispersion stabilizer in order to control the particle size of the toner particles 45a, to sharpen the particle size distribution, and to suppress the coalescence of the toner particles 45a during the manufacturing process. Dispersion stabilizers are generally broadly classified into polymers that exhibit repulsive force due to steric hindrance and poorly water-soluble inorganic compounds that stabilize dispersion by electrostatic repulsive force. Fine particles of poorly water-soluble inorganic compounds are preferably used because they dissolve in acid or alkali and can be easily removed by washing with acid or alkali after polymerization.

[0118] After the granulation step or while the granulation step is being carried out, the temperature is preferably set to 50°C or more and 90°C or less to polymerize the polymerizable monomer contained in the polymerizable monomer composition to obtain a toner particle dispersion (polymerization step). In the polymerization step, it is preferable to carry out a stirring operation so that the temperature distribution in the container is uniform. When a polymerization initiator is added, it can be added at any timing and for any required time. In addition, the temperature may be raised in the latter half of the polymerization reaction in order to obtain a desired molecular weight distribution, and further, in order to remove unreacted polymerizable monomers, by-products, etc. from the system, a part of the aqueous medium may be distilled off by a distillation operation in the latter half of the reaction or after the reaction is completed. The distillation operation can be carried out under normal pressure or reduced pressure.

[0119] The particle size of the toner particles 45a is preferably 3.0 μm or more and 10.0 μm or less in terms of obtaining a high-definition and high-resolution image. The weight-average particle size of the toner can be measured by a capillary electrical resistance method. For example, it can be measured using a Coulter Counter Multisizer 3 (manufactured by Beckman Coulter, Inc.).

[0120] The toner particle dispersion thus obtained is sent to a filtration process for solid-liquid separation of the toner particles 45a and the aqueous medium. The solid-liquid separation for obtaining the toner particles 45a from the obtained toner particle dispersion can be performed by a general filtration method. Thereafter, in order to remove foreign matter that has not been completely removed from the toner particle surface, it is preferable to perform further washing by reslurrying or washing with washing water. After sufficient washing, solid-liquid separation is performed again to obtain a toner cake. Thereafter, the toner is dried by a known drying means, and if necessary, a particle group having a particle size other than the specified particle size is separated by classification to obtain the toner particles 45a. The particle group having a particle size other than the specified particle size separated at this time may be reused to improve the final yield.

[0121] The toner particles T in this embodiment are produced by a suspension polymerization method, and the toner physical properties are a weight average particle size of 6.5 μm and an average theoretical surface area of ​​1.0 m 2 / g, Tg 57°C. Dry silica fine powder [BET specific surface area 300 m2 For 100 parts of cellulose acetate / g, 25 parts of dimethyl silicone oil were used for hydrophobization. Commercially available zinc stearate (MZ2, manufactured by Nippon Oil & Fats) was used as the fatty acid metal salt as external additive B. The median diameter (D50s) on a volume basis was 1.29 μm, and the span value B was 1.61. The external additives are described in detail below.

[0122] (External additives) -Lubricant particles- In this embodiment, positively charged lubricant particles 45c are externally added to the toner particles 45a as an external additive B. The lubricant particles 45c are positively charged, that is, the charging polarity is opposite to that of the toner particles 45a, so that the lubricant particles 45c are not easily transferred to the recording material P at the transfer portion Nt. Therefore, the lubricant particles 45c attached to the surface of the photosensitive drum 1 can easily reach the cleaning member 63, and the lubrication at the cleaning portion can be ensured. Examples of the positively charged lubricant particles 45c include fatty acid metal salt particles. The fatty acid metal salt particles are salt particles made of fatty acid and metal.

[0123] The fatty acid may be either a saturated fatty acid or an unsaturated fatty acid. The number of carbon atoms in the fatty acid is 10 or more and 25 or less (preferably 12 or more and 22 or less). The number of carbon atoms in the fatty acid includes the carbon of the carboxy group.

[0124] Examples of fatty acids include saturated fatty acids such as behenic acid, stearic acid, palmitic acid, myristic acid, and lauric acid; and unsaturated fatty acids such as oleic acid, linoleic acid, and ricinoleic acid. Among these fatty acids, stearic acid and lauric acid are preferred, and stearic acid is more preferred.

[0125] The metal is preferably a divalent metal. Examples of the metal include magnesium, calcium, aluminum, barium, and zinc. Among these metals, zinc is preferred.

[0126] Examples of fatty acid metal salt particles include metal salts of stearic acid such as aluminum stearate, calcium stearate, potassium stearate, magnesium stearate, barium stearate, lithium stearate, zinc stearate, copper stearate, lead stearate, nickel stearate, strontium stearate, cobalt stearate, and sodium stearate; palmitates such as zinc palmitate, cobalt palmitate, copper palmitate, magnesium palmitate, aluminum palmitate, and calcium palmitate; Metal salts of fatty acid; metal salts of lauric acid such as zinc laurate, manganese laurate, calcium laurate, iron laurate, magnesium laurate, and aluminum laurate; metal salts of oleic acid such as zinc oleate, manganese oleate, iron oleate, aluminum oleate, copper oleate, magnesium oleate, and calcium oleate; metal salts of linoleic acid such as zinc linoleate, cobalt linoleate, and calcium linoleate; metal salts of ricinoleic acid such as zinc ricinoleate and aluminum ricinoleate; and the like. Among fatty acid metal salt particles, preferred are metal salts of stearic acid or metal salts of lauric acid, more preferred are zinc stearate or zinc laurate particles, and even more preferred are zinc stearate particles.

[0127] The amount of the positively charged lubricant particles 45c added to the toner particles 45a is preferably 0.6% by mass (wt%) or less with respect to the total mass of the toner particles 45a. The greater the amount of the positively charged lubricant particles 45c added to the toner particles 45a, the greater the effect of reducing the torque for rotating the photosensitive drum 1 by reducing the frictional force between the photosensitive drum 1 and the cleaning member 63. However, if the positively charged lubricant particles 45c are added to the toner particles 45a in excess, the fluidity of the toner T may deteriorate. One example of the effect of the deterioration of the fluidity of the toner T is that the density of a solid image in the rear half (the rear end side in the conveying direction) of the surface of the recording material P becomes low, and image defects such as so-called "solid image tracking defects" tend to occur. From this viewpoint, the amount of the positively charged lubricant particles 45c added to the toner (initial filling toner) T is preferably 0.6% by mass or less with respect to the total mass of the toner particles 45a, as described above. Furthermore, if the amount of the positively charged lubricant particles 45c added to the toner particles 45a is too small, it may not be possible to sufficiently obtain the effect of reducing the torque for rotating the photosensitive drum 1 by reducing the frictional force between the photosensitive drum 1 and the cleaning member 63. From this viewpoint, the amount of the positively charged lubricant particles 45c added to the toner (initial filling toner) T is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more, with respect to the total mass of the toner particles 45a.

[0128] The average particle diameter of the positively charged lubricant particles 45c is preferably 0.5 μm or more and 2 μm or less. If the average particle diameter of the positively charged lubricant particles 45c is smaller than 0.5 μm, the lubricant particles 45c may be difficult to remove from the toner T and difficult to be supplied to the surface of the photosensitive drum 1. If the average particle diameter of the positively charged lubricant particles 45c is larger than 2 μm, the lubricant particles 45c may be too easily removed from the toner particles 45a. As a result, the lubricant particles 45c may be left behind in the developing container 41 without passing through the developing blade 46 in the developing device 4 and difficult to be supplied to the surface of the photosensitive drum 1.

[0129] Here, the average particle size of the lubricant particles 45c can be measured, for example, by the following method. Each primary particle of the lubricant particles 45c is observed and an image is taken by a scanning electron microscope (SEM) (Hitachi, Ltd.: S-4100). Then, this image is imported into an image analyzer (LUZEXIII, Nireco, Ltd.), and the area of ​​each particle is measured by image analysis of the primary particles, and the circle-equivalent diameter is calculated from this area value. This calculation of the circle-equivalent diameter is performed for 100 particles. Then, the 50% diameter (D50) in the cumulative frequency based on volume of the obtained circle-equivalent diameter is set as the average primary particle size of the lubricant particles (average circle-equivalent diameter D50). The magnification of the electron microscope is adjusted so that about 10 to 50 lubricant particles are captured in one visual field, and the circle-equivalent diameter of the primary particles is obtained by combining the observations of multiple visual fields.

[0130] The coverage Wb of the lubricant particles (fatty acid metal salt) 45c is calculated as follows.

[0131] The coverage rate Wb of the fatty acid metal salt is measured by ESCA (X-ray photoelectron spectroscopy) (Quantum 2000, manufactured by ULVAC-PHI, Inc.).

[0132] The sample holder used was a 75 mm square platen (equipped with a screw hole with a diameter of about 1 mm for fixing the sample) that came with the device. The screw hole in the platen is a through hole, so the hole is blocked with resin or the like to create a recess for powder measurement with a depth of about 0.5 mm. The measurement sample (toner or external additive B (fatty acid metal salt) alone) is packed into the recess with a spatula or the like, and the sample is created by leveling it off.

[0133] The ESCA measurement conditions are as follows. □Analysis method: Narrow analysis X-ray source: Monochrome Al Kα □X-ray conditions: 100μ25W15kV □ Photoelectron capture angle: 45 degrees □PassEnergy: 58.70eV Measurement range: φ100μm First, the toner is measured. The quantitative value of the metal atoms contained in the fatty acid residual metal salt is calculated using C 1s (BE280-295eV), O1s (BE525-540eV), Si 2p (BE95-113eV) and the element peaks of the metal atoms of the fatty acid metal salt used. The quantitative value of the metal atoms obtained here is designated as X1.

[0134] Next, in the same manner, elemental analysis of the fatty acid metal salt alone is carried out, and the quantitative values ​​of the elements contained in the fatty acid metal salt obtained here are designated as X2.

[0135] Using the above X1 and X2, the coverage rate Wb of the fatty acid metal salt is calculated according to the following formula (Formula 1). Wb(%)=X1 / X2×100 (Formula 1)

[0136] -Silica particles- As the silica particles 45b, any particles containing silica, i.e., SiO2 as a main component can be used, and they may be crystalline or amorphous. In addition, as the silica particles 45b, particles manufactured from a silicon compound such as water glass or alkoxysilane as a raw material, or particles obtained by crushing quartz, may be used.

[0137] Specifically, examples of the silica particles 45b include sol-gel silica particles, aqueous colloidal silica particles, alcoholic silica particles, fumed silica particles obtained by a gas phase method, and fused silica particles. Among these, the sol-gel silica particles are preferred as the silica particles 45b from the viewpoint of satisfying the following characteristics.

[0138] Moreover, the silica particles 45b are preferably monodisperse and spherical. The monodisperse spherical silica particles are dispersed almost uniformly on the surface of the toner particles 45a, and a stable spacer effect can be obtained.

[0139] The average particle size (primary particle size) of the silica particles 45b is preferably 1 nm or more and 200 nm or less. From the viewpoint of durability, it is also possible to mix a plurality of types of silica particles 45b, such as small silica particles having an average particle size (primary particle size) of 1 nm or more and 30 nm or less and large silica particles having an average particle size (primary particle size) of 30 nm or more and 200 nm or less. By using silica particles 45b with such an average particle size, it is possible to obtain a good effect of ensuring the fluidity of the toner T and improving the chargeability.

[0140] The amount of the silica particles 45b added to the toner particles 45a is preferably 0.5% by mass or more and 10% by mass or less in total with respect to the total mass of the toner particles 45a. By adding the silica particles 45b in such an amount, the fluidity of the toner T can be ensured and the charging property can be improved.

[0141] Regarding the silica particles 45b, "monodisperse" can be defined by the standard deviation of the average particle diameter including aggregates, and the standard deviation is preferably equal to or less than the volume average particle diameter D50 × 0.22. Regarding the silica particles 45b, "spherical" can be defined by the average circularity, and the average circularity is preferably equal to or more than 0.75 and equal to or less than 1.0, more preferably equal to or more than 0.9 and equal to or less than 1.0, and even more preferably equal to or more than 0.92 and equal to or less than 0.98.

[0142] Here, the average particle size of silica particles can be measured by the following method. Primary particles of silica particles are observed and images are taken using a scanning electron microscope (SEM) (Hitachi, Ltd.: S-4100). Then, this image is imported into an image analyzer (LUZEXIII, Nireco, Ltd.), and the area of ​​each particle is measured by image analysis of the primary particles, and the circle-equivalent diameter is calculated from this area value. This calculation of the circle-equivalent diameter is performed for 100 silica particles. Then, the 50% diameter (D50) in the cumulative frequency based on volume of the obtained circle-equivalent diameter is taken as the average primary particle size of silica particles (average circle-equivalent diameter D50). The magnification of the electron microscope is adjusted so that 10 to 50 silica particles are captured in one visual field, and the circle-equivalent diameter of the primary particles is obtained by combining the observations of multiple visual fields.

[0143] The average circularity of silica particles can be measured by the following method: First, the primary particles of the silica particles are observed by an SEM device, and the circularity of the silica particles is calculated as "100 / SF2" from the planar image analysis of the obtained primary particles by the following formula (Formula 2). Circularity (100 / SF2)=4π×(A / I2) (Equation 2) [In formula 2, I represents the perimeter of the primary particle on the image, and A represents the projected area of ​​the primary particle.] The average circularity of the silica particles is obtained as the 50% circularity in the cumulative frequency of the circularities of 100 primary particles obtained by the above-mentioned planar image analysis.

[0144] The coverage of the toner surface with silica particles is calculated as follows.

[0145] The following apparatus is used under the following conditions to perform elemental analysis of the toner surface. Measurement device: Quantum2000 (product name, manufactured by ULVAC-PHI, Inc.) X-ray source: Monochrome Al Kα □Xray Setting:100μmφ(25W(15kV)) Photoelectron take-off angle: 45 degrees □Neutralization conditions: Use neutralization gun and ion gun together □Analysis area: 300μm×200μm □Pass Energy: 58.70 eV □ Step size: 0.125 eV □Analysis software: Multipak (PHI) When determining the coverage of the silica particles 45b, the quantitative value of the Si atoms is calculated using the peaks of C 1s (BE280 to 295 eV), O1s (BE525 to 540 eV) and Si 2p (BE95 to 113 eV). The quantitative value of the Si atoms obtained here is designated as Y1.

[0146] Next, in the same manner as the above-mentioned elemental analysis of the toner surface, elemental analysis of the silica particles alone is carried out, and the quantitative value of the Si atoms obtained here is designated as Y2.

[0147] The coverage rate Ws (%) of the toner surface by the silica particles is defined by the following formula (Formula 3) using the above Y1 and Y2. Ws(%)=(Y1 / Y2)×100 (Formula 3) The same sample is measured 1000 times, and the arithmetic mean value is used.

[0148] In determining the quantitative value Y2, if the external additive used for external addition is available, it may be used for measurement.

[0149] -External addition method- In this embodiment, a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) was used as a surface modification device to externally add silica particles 45b and lubricant particles 45c to toner particles 45a. The details are as described in JP 2016-38591 A.

[0150] Briefly, as shown in FIG. 9, the surface modification device 201 is configured to include a processing chamber (processing tank) 210, an agitating blade 220 as a fluttering means, a rotating body 230, a driving motor 250, and a surface modification control unit 260. Here, the processing chamber 210 is for accommodating the object to be processed, including the toner particles and the external additives. The agitating blade 220 is rotatably provided at the bottom of the processing chamber 210, which is below the rotating body 230 in the processing chamber 210. The rotating body 230 is rotatably provided above the agitating blade 220. The processing chamber 210 is a cylindrical container having a substantially flat bottom, and is provided with a drive shaft 211 for mounting the agitating blade 220 and the rotating body 230 at the substantially center of the bottom. The agitating blade 220 is configured to be able to flutter the object to be processed, including the toner particles and the external additives, in the processing chamber 210 by rotating. The agitator blade 220 has a blade portion 221 that extends from the center of rotation toward the outside (diametrically outward (outer diameter direction), outer diameter side), and the tip of the blade portion 221 is shaped so as to bounce up the material to be treated. As the agitator blade 220 rotates, the material to be treated rises while rotating in the same direction as the agitator blade 220 in the treatment chamber 210, and then descends due to gravity. In this way, the material to be treated is mixed uniformly. The rotor 230 is composed of a rotor main body and a treatment section having a treatment surface that collides with the material to be treated as the rotor 230 rotates to treat the material to be treated. As the rotor 230 rotates, the material to be treated collides with the treatment surface, thereby disintegrating the external additive agglomerates.

[0151] <Initial toner filling and replenishment toner> In a method of replenishing toner from a toner cartridge to the developing device 4 (process cartridge 10), the toner T in the developing device 4 may lose external additives from the surface of the toner through use due to embedding of the external additives present on the toner surface. For this reason, when the toner T in the developing device 4 is reduced and toner T' in the toner cartridge 9 is replenished, a difference in physical properties occurs between the toner T originally present in the developing device 4 and the toner T' in the toner cartridge 9. This difference in physical properties causes image problems such as fogging and uneven density due to differences in the amount of charge of the toner. As a result, this may become a factor that hinders the extension of the life of the developing device 4 and the process cartridge 10.

[0152] FIG. 5 shows the change in coverage of the silica particles 45b as the external additive A, which is the first external additive in this embodiment, with respect to the initial filled toner T according to the number of printed sheets. The vertical axis indicates the coverage of the silica particles 45b with respect to the initial filled toner T, and the horizontal axis indicates the number of printed sheets. Here, the number of printed sheets is correlated with the number of rotations of the developing roller 43 and the toner consumption of the filled toner T. The black circles indicate the case where printing is performed at an average printing rate of 2.0%, and the white circles indicate the case where printing is performed at an average printing rate of 5.0%. In both cases, it can be seen that the coverage of the silica particles 45b with respect to the initial filled toner T decreases as the number of printed sheets increases. This is because the silica particles 45b present on the surface of the filled toner T are embedded in the surface of the filled toner T due to the influence of stirring in the developing device 4, shear in the conveying section, and friction with the developing blade 46 that regulates the layer thickness of the developing roller 43. Here, the decrease in coverage is more noticeable with an average printing rate of 2.0% than with an average printing rate of 5.0%. This is because the toner T is consumed faster and the stress on the toner T is less when the average printing rate is higher. Also, the initial rate of decrease in the coverage rate is high, and the coverage rate thereafter converges more gradually. In this embodiment, the coverage rate of the silica particles 45b of the initially filled toner T is 45%. When the average printing rate is then set to 2.0% and the number of printed sheets is increased, the coverage rate of the silica particles 45b of the filled toner T converges to 12%.

[0153] FIG. 6 shows the change in coverage of zinc stearate as the external additive B, which is the second external additive in this embodiment, with respect to the initial filled toner T according to the number of printed sheets. The vertical axis indicates the coverage of zinc stearate with respect to the initial filled toner T, and the horizontal axis indicates the number of printed sheets. It can be seen that the coverage of zinc stearate with respect to the initial filled toner T decreases as the number of printed sheets increases. As explained in FIG. 5, this is because the zinc stearate present on the surface of the filled toner T is embedded in the surface of the filled toner T due to the influence of stirring in the developing device 4, shear in the conveying section, and friction with the developing blade 46 that regulates the layer thickness of the developing roller 43. In addition, the initial rate of decrease in coverage is high, and the coverage thereafter gradually converges. In this embodiment, the coverage of zinc stearate of the initial filled toner T is set to 12%. From that state, the average printing rate is set to 2.0%, and the number of printed sheets is increased, and the coverage of zinc stearate of the filled toner T converges to 6%.

[0154] Therefore, in this embodiment, the toner T' supplied from the toner cartridge 9 is made to have a surface state equivalent to that of a predetermined number of times of rubbing, so that the difference in physical properties is reliably reduced and fogging and uneven density can be suppressed. In this embodiment, the coverage rate of the external additive of silica particles 45b on the toner particles 45a of the supply toner T' of the toner cartridge 9 is made lower than the coverage rate of the external additive of silica particles 45b on the toner particles 45a of the initial filled toner T of the new process cartridge 10. Also, the coverage rate of the external additive of lubricant particles 45c on the toner particles 45a of the supply toner T' of the toner cartridge 9 is made lower than the coverage rate of the external additive of lubricant particles 45c on the toner particles 45a of the initial filled toner T of the new process cartridge 10. The amount of externally added lubricant particles 45c on the toner particles 45a of the supply toner T' contained in the toner cartridge 9 may be 0 mass % (i.e., the lubricant particles 45c may not be externally added to the toner particles 45a of the supply toner T'). In a configuration in which the toner cartridge 9 can be detached from and replaced with respect to the developing device 4, the difference in physical properties between the initial filling toner T as the initial developer present in the developing device 4 and the toner T' as the replenishment developer in the toner cartridge 9 can be reduced, thereby suppressing image defects.

[0155] <Evaluation Results> Evaluation experiments were carried out to confirm the effects of this embodiment for an example (Example 1) according to this embodiment and comparative examples (Comparative Examples 1, 2, and 3) for comparison with this embodiment.

[0156] Table 1 shows the mixing conditions of the toner particles filled in the process cartridge 10 and the toner cartridge 9, the conditions for preparing the amount of addition, and the measurement results of the coverage rate of external additive A and the coverage rate of external additive B of the prepared toner particles 45a. The amounts of silica particles and zinc stearate added to the toner T and T' filled in the process cartridge 10 and the toner cartridge 9 were the same. The amount of silica particles as the first external additive contained in the initial developer T is I1, and the amount of silica particles as the first external additive contained in the replenishment developer T' is H1. In addition, if the amount of zinc stearate as the second external additive contained in the initial developer T is I2, and the amount of zinc stearate as the second external additive contained in the replenishment developer T' is H2, then the coverage rate of 0.9

[0157] [Table 1]

[0158] ​For the study, the process cartridge 10 and the toner cartridge 9 of the present embodiment were used. The initial fill toner T filled in the developing device 4 of the process cartridge 10 and the replenishment toner T' contained in the toner cartridge 9 were prepared using a Henschel mixer (manufactured by Nippon Coke & Engineering Co., Ltd.) as the above-mentioned surface modification device. Table 1 shows the external addition conditions, that is, the amount of external additive (silica particles 45b, lubricant particles 45c) added, and the rotation speed of the tip of the blade of the surface modification device 201 and the time during which the blade rotates. First, silica particles (small silica particles) 45b were added to the toner particles 45a, and the surface modification device 201 shown in FIG. 9 treated at the blade tip circumferential speed and time shown in Table 1. Next, the lubricant particles 45c were added as shown in Table 1, and the surface modification device treated at the blade tip circumferential speed and time shown in Table 1. Zinc stearate was commonly adopted as the lubricant particles 45c. Here, as shown in Table 1, the toner cartridge 1, the toner cartridge 2, the toner cartridge 3, and the toner cartridge 4 were prepared as the initial filling toner T for the process cartridge 10 and the toner cartridge refill toner T' for the toner cartridge. For the toner cartridge 1, the toner T' coated with the external additives A and B was used. Specifically, the coating rate of the external additive A was adjusted to 45%, and the coating rate of the external additive B was adjusted to 12%. For the toner cartridge 2, the toner T' was used, which was adjusted to the coating rate of the external additive A to 12%, which is smaller than 45%, and the coating rate of the external additive B to 6%, which is smaller than 12%. Compared to the adjustment conditions of the toner used for the process cartridge 10 and the toner cartridge 1, the rotation speed of the tip of the blade of the surface modification device was increased and the time during which the blade rotated was lengthened for adjustment. Thereafter, the coating rates of the external additive A and the external additive B were adjusted for the toner cartridges 3 and 4 by adjusting the rotation speed of the tip of the blade of the surface modification device and the time during which the blade rotated. For the toner cartridge 3, a toner T' was used, which was adjusted so that the coverage of the external additive A was 45%, the same as that of the process cartridge 10, and the coverage of the external additive B was 6%, which was lower than 12%.For toner cartridge 4, toner T' was used, which was adjusted so that the coverage of external additive A was 12%, which is lower than 45%, and the coverage of external additive B was 12%, the same as that of process cartridge 10. Although the coverage of external additive A in toner cartridge 1 and toner cartridge 3 is the same, the first stage conditions are different because the second stage conditions are different. By determining the first stage conditions while taking into account the second stage conditions, the coverage of the external additive that is finally added to the toner is adjusted.

[0159] Here, toner cartridge 1 is Comparative Example 1, toner cartridge 2 is Example 1, toner cartridge 3 is Comparative Example 2, and toner cartridge 4 is Comparative Example 3.

[0160] The results obtained when the initially filled toner T of the process cartridge 10 is replenished with toner T' of toner cartridge 1, toner cartridge 2, toner cartridge 3, and toner cartridge 4, respectively, are shown below.

[0161] A new process cartridge 10 is filled with 150 g of initial filled toner T, and a new toner cartridge 9 is filled with 600 g of replenishment toner T'. After 100 g of the 150 g initial filled amount of the process cartridge 10 is used by printing, the toner cartridge 9 filled with replenishment toner T' adjusted under the conditions in Table 1 is mounted on the image forming apparatus 100. After mounting, 1000 sheets are printed while replenishment of toner T' from the toner cartridge 9 to the process cartridge 10.

[0162] Toner cartridge 1 (Comparative example 1): When the printing operation proceeds, the toner T in the process cartridge 10 is used, and in a state where the coverage rate of the external additive A and the external additive B of the toner particles 45a is reduced, the toner T' with a high coverage rate is supplied little by little from the toner cartridge. In this state, the toner T with a low coverage rate and a low toner charge amount is brought around and coated on the developing roller 43 by the toner T' with a high coverage rate and a high toner charge amount. This causes fogging caused by the toners with different charge amounts. That is, this fogging is caused by the toners with a high charge amount taking the charge of the toners with a low charge amount, and the charge amount of the toners is further reduced. The difference from the toner cartridges 2 and 4 described later is that the situation in which a small amount of toner with a high charge amount is supplied to the toner in the developing device 4 with a low charge amount is a state in which the toner with a low charge amount, which is easily affected, is rich, so the influence due to the difference in charge amount is large. This is also the case with the configuration of the external additive B. Therefore, since zinc stearate is constantly supplied from the toner cartridge, fusion to the developing blade 46 occurred after 1000 sheets were printed.

[0163] Toner cartridge 3 (Comparative example 2): As the printing operation progresses, when the coverage rate of the external additive A of the toner in the process cartridge 10 decreases, toner with a high coverage rate A is supplied little by little from the toner cartridge. Therefore, fogging caused by toner with a different charge amount occurred, similar to that in Comparative example 1.

[0164] Toner cartridge 4 (Comparative example 3): As the printing operation progresses, when the coverage rate of the external additive B of the toner in the process cartridge 10 decreases, toner with a high coverage rate B is supplied little by little from the toner cartridge. Since zinc stearate is constantly supplied from the toner cartridge, fusion to the developing blade 46 occurred after 1,000 sheets were printed.

[0165] Toner cartridge 2 (Example 1): For both external additive A and external additive B, toner with low coverage of external additive A and external additive B is replenished to the process cartridge 10. Even after printing 1000 sheets, no image defects occurred. The reason why image defects did not occur is considered as follows. When toner T' with low coverage of external additive A and external additive B is replenished in small amounts to toner T with high coverage of external additive A and external additive B, there is a lot of toner with high coverage and strong charge. Therefore, it is coated on the developing roller 43. The difference in phenomenon from the toner cartridges 1, 3, and 4 described above is that in a situation where a small amount of toner with a low charge is replenished to the toner in the developing device 4 with a large charge amount that is not easily affected, the toner with a large charge amount is in a rich state. Therefore, the difference is that the effect due to the difference in charge amount is small. In particular, in the toner cartridge 2, the coverage of the external additive is adjusted for both of the two types of external additive A and B. Therefore, the effect of both external additive A and external additive B is small. On the other hand, in toner cartridge 1, it is influenced by both external additive A and external additive B, in toner cartridge 3, it is influenced by external additive A, and in toner cartridge 4, it is influenced by external additive B.

[0166] The filled toner T in the process cartridge 10 is sufficiently agitated in the process cartridge 10 while the toner with the higher coverage is being preferentially used, and the overall coverage rate decreases. As a result, in the latter half of the durability test, the difference in coverage rate with the toner T' supplied from the toner cartridge 9 decreases, so that the occurrence of fogging can be suppressed throughout the life of the toner cartridge.

[0167] Here, as shown in FIG. 7, the differences between the coverage rate of the filled toner T contained in the process cartridge 10 and the coverage rate of the replenishment toner T' contained in the toner cartridge 9 when replacing the toner cartridges 1 and 3 containing a large amount of external additive A are Δa1, Δa2, and Δa3. The differences between the coverage rate of the filled toner T contained in the process cartridge 10 and the coverage rate of the replenishment toner T' contained in the toner cartridge 9 when replacing the toner cartridges 2 and 4 containing a small amount of external additive A are Δb1, Δb2, and Δb3. The average printing rate is 2.0%. In this case, Δa1>Δb1, Δa2>Δb2, and Δa3>Δb3. That is, since the above differences Δb1, Δb2, and Δb3 are small, the state difference between the replenishment toner T' and the filled toner T when the replenishment toner T' is replenished is small. Also, Δa1<Δa2<Δa3, and the difference Δa becomes larger as the number of printed sheets increases. Therefore, it can be said that the burial of the external additive A in the filled toner T is progressing.

[0168] Also, as shown in FIG. 8, the differences between the coverage of the filled toner T contained in the process cartridge 10 and the coverage of the replenishment toner T' contained in the toner cartridge 9 when replacing the toner cartridges 1 and 4 containing a large amount of external additive B are Δc1, Δc2, and Δc3. The average printing rate is 2.0%. The differences between the coverage of the filled toner T contained in the process cartridge 10 and the coverage of the replenishment toner T' contained in the toner cartridge 9 when replacing the toner cartridges 2 and 3 containing a small amount of external additive B are Δd1, Δd2, and Δd3. Then, Δc1>Δd1, Δc2>Δd2, and Δc3>Δd3. That is, since the above differences Δd1, Δd2, and Δd3 are small, the state difference between the replenishment toner T' and the filled toner T when the replenishment toner T' is replenished is small. Also, Δc1<Δc2<Δc3, and the difference Δc becomes larger as the number of printed sheets increases. Therefore, it can be said that the burial of the external additive B in the filled toner T is progressing.

[0169] As described above, in a configuration in which the toner cartridge 9 containing two or more types of external additives is detachably attached to the process cartridge 10, the following configuration is preferable: The coverage of each external additive on the toner particles 45a in the toner cartridge 9 is set to be equal to or close to the coverage that converges when printing is continued at the minimum printing rate (2.0% in this embodiment), that is, when printing is continued at the minimum printing rate until the filled toner T is used up.

[0170] Thus, in this embodiment, the image forming apparatus 100 has a photosensitive drum 1 as a rotatable image carrier, and a charging roller 2 as a charging member that charges the surface of the photosensitive drum 1. The image forming apparatus 100 has a developing unit 4 that supplies a developer T to the surface of the photosensitive drum 1 charged by the charging roller 2 to form a developer image. The developing unit 4 has a developing roller 43 as a rotatable developing member that carries the developer T on its surface, and a storage section 42 that stores the developer T to be supplied to the developing roller 43. The developing unit 4 has a supply container 9 that is detachable from the developing unit 4 and can store a supply developer T' as the developer T and supply the supply developer T' to the storage section 42 of the developing unit 4. The storage section 42 of a new developing unit 4 is pre-filled with an initial developer T, which is a predetermined amount of developer T, and the initial developer T and the supply developer T' contain at least toner particles 45a, a first external additive 45b, and a second external additive 45c. The amount of the first external additive 45b contained in the initial developer T is defined as I1, the amount of the first external additive 45b contained in the replenishment developer T' as H1, the amount of the second external additive 45c contained in the initial developer T as I2, and the amount of the second external additive 45c contained in the replenishment developer T' as H2. The coverage of the first external additive 45b in the initial developer T measured by ESCA is defined as Wpa, the coverage of the first external additive 45b in the replenishment developer T' as Wta, the coverage of the second external additive 45c in the initial developer T as Wpb, and the coverage of the second external additive 45c in the replenishment developer T' as Wtb. In this case, 0.9

[0171] ​As described above, according to this embodiment, in a configuration in which a supply container 9 containing developer T' to be replenished to the developing device 4 can be attached to the developing device 4, image defects caused by the replenishment of developer T' can be suppressed. EXAMPLES

[0172] The basic configuration and operation of the image forming apparatus 100 of the second embodiment are similar to those of the first embodiment. Elements having the same or corresponding functions or configurations as those of the first embodiment are given the same reference numerals as those of the first embodiment, and detailed descriptions thereof will be omitted.

[0173] <Forced toner consumption mode> The forced toner consumption mode as the supply operation in this embodiment will be described in detail below. In this embodiment, the configuration of the control unit 120 is the configuration shown in FIG.

[0174] When image formation starts, the image data input to the control unit 120 is read, and the image ratio of the image is calculated from the video count data by a calculation unit 124 provided in the control unit 120, and stored in the RAM 123. The image ratios of the past 100 sheets including the image are sequentially recorded in the RAM 123, and the image ratio data of the past 100 sheets is read from the RAM 123 into the control unit 120, and the average print ratio of the past 100 sheets is calculated by a calculation unit 125 based on these data. Here, the information stored in the RAM 123 may be saved in a memory such as a ROM 122 provided in the control unit 120, or a memory MP provided in the process cartridge 10 or a memory MT provided in the toner cartridge 9. In this embodiment, the average print ratio is calculated for every 100 sheets, but this is not limited to this.

[0175] The control unit 120 judges whether the average printing rate calculated by the calculation unit 125 based on the printing rate calculated by the calculation unit 124 is below a first threshold value (2.0% in the present embodiment), which is a predetermined value. If the average printing rate is below the first threshold value, which is a predetermined value, in the present embodiment, toner is consumed so that the average printing rate becomes 2.0%. For this purpose, as a non-image area, toner purging is performed during a paper-to-paper operation between the rear end of the preceding sheet P and the front end of the succeeding sheet P during continuous image formation, and during a post-rotation operation after the end of the image forming operation. Specifically, an electrostatic latent image is formed over the entire axial area of ​​the photosensitive drum 1 with the laser light irradiation amount set to FFh (maximum), and this is developed. That is, the toner consumption amount is adjusted by the length of the photosensitive drum 1 in the rotation direction, so that the average printing rate obtained by adding up the output image and the toner forcibly consumed becomes 2.0%. This toner consumption amount may be such that the printing rate of the output image is constant as in the present embodiment, or may be a constant amount. That is, the control unit 120 controls the calculation unit 125 to accumulate amounts related to the printing rate and calculate the average printing rate per sheet of recording material. Then, when the average printing rate crosses the first threshold, the control unit 120 controls to execute a supply operation. That is, when the average printing rate is smaller than the first threshold, the control unit 120 controls to execute a supply operation.

[0176] By controlling in this manner, it is possible to stably control the average printing rate. As a result, the coverage rate of the external additives A and B of the toner T in the process cartridge 10 becomes close to the coverage rate of the external additives A and B of the replenishment toner T'. Therefore, in a configuration in which the replenishment container 9 containing the developer T' to be replenished to the developing device 4 can be attached to the developing device 4, image defects caused by the replenishment of the developer T' can be suppressed.

[0177] (Other embodiments) Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above-described embodiments.

[0178] In the above embodiment, two types of external additives, external additive A and external additive B, are used, but this is not limiting and any external additive may be added as long as the coverage rate can be measured. For example, a hydrotalcite compound that can be identified as the element Mg or Al is preferable. In the case of a negative polarity toner such as that of this embodiment, the hydrotalcite compound often has a positive polarity compared to the toner particles and silica fine particles, and it is considered that the hydrotalcite compound exerts an adhesive force on both the toner particles and the silica fine particles. Therefore, the presence of the hydrotalcite compound makes it difficult for the hydrotalcite compound to separate from the toner particles, which improves fogging and transferability. Furthermore, the developing device 4 uses a contact development method in which the photosensitive drum 1 and the developing roller 43 are arranged in contact with each other, but is not limited to this. The developing device may use a two-component development method using a two-component developer, or a non-contact development method in which the photosensitive drum 1 and the developing roller 43 are arranged opposite each other with a predetermined gap between them. In other words, the developer is not limited to the non-magnetic one-component developer of the above embodiment, and may be a two-component developer or a magnetic one-component developer.

[0179] It is also possible to store toner information and related control information in memory MT in toner cartridge 9, and to perform appropriate operations for each toner cartridge 9. Specifically, coverage information of toner particles 45a is calculated from the usage status of process cartridge 10, and stored in memory MP in process cartridge 10 and control unit 120. Then, the control unit 120 may read the toner information in toner cartridge 9, and perform special operations such as forced toner consumption and extension of toner stirring time according to the coverage of toner particles in process cartridge 10 and toner cartridge 9. It is also effective to change the bias control.

[0180] The image forming apparatus to which the present invention can be applied is not limited to the image forming apparatus having the basic configuration shown in the above embodiment. For example, the present invention can be applied to an image forming apparatus that has a plurality of detachable process cartridges and can transfer a plurality of color toner images to a recording material using an intermediate transfer body such as an intermediate transfer belt to form a full-color image. In the above embodiment, the image forming apparatus is configured so that the process cartridge is detachable. However, the present invention is not limited to such an aspect, and the present invention can be applied to an image forming apparatus in which a process unit similar to that constituting the process cartridge in the above embodiment is provided in the apparatus main body. In addition, the developing device may be substantially detachable from the apparatus main body by itself. Examples of the image forming apparatus include a copying machine, a printer (laser beam printer, LED printer, etc.), a facsimile machine, a word processor, and a combination machine (multifunction printer) thereof.

[0181] The disclosure of this embodiment includes the following configuration.

[0182] (Configuration 1) A rotatable image carrier; a charging member for charging the surface of the image bearing member; a developing unit for supplying a developer to the surface of the image carrier charged by the charging member to form a developer image, the developing unit including a rotatable developing member that carries the developer on its surface, and a container that contains the developer to be supplied to the developing member; a supply container that is detachable from the developing unit, that contains a supply developer as the developer, and that can supply the supply developer to the container of the developing unit, The container of the new developing unit is filled in advance with a predetermined amount of initial developer, which is the developer, the initial developer and the replenishment developer contain at least toner particles, and a first external additive and a second external additive, The amount of the first external additive contained in the initial developer is defined as I1, the amount of the first external additive contained in the replenishment developer is defined as H1, the amount of the second external additive contained in the initial developer is defined as I2, and the amount of the second external additive contained in the replenishment developer is defined as H2, When the coverage of the first external additive in the initial developer measured by ESCA is defined as Wpa, the coverage of the first external additive in the replenishment developer as Wta, the coverage of the second external additive in the initial developer as Wpb, and the coverage of the second external additive in the replenishment developer as Wtb, 0.9

[0183] (Configuration 2) a calculation unit that calculates an amount related to a printing rate of an image formed on a recording material in an image forming operation when the image forming operation is performed; a control unit that controls rotation of the photosensitive drum and the developing member based on the amount calculated by the calculation unit, and controls a supply operation of supplying the developer from the developing member to the surface of the photosensitive drum so as to be executable; The image forming apparatus according to configuration 1, characterized in that the control unit controls the calculation unit to accumulate amounts related to the printing rate and calculate an average printing rate per sheet of recording material, and controls the supply operation to be executed when the average printing rate is smaller than a first threshold value.

[0184] (Configuration 3) 3. The image forming apparatus according to claim 1, wherein the first external additive is silica fine particles.

[0185] (Configuration 4) 3. The image forming apparatus according to claim 1, wherein the second external additive is a fatty acid metal salt. [Explanation of symbols]

[0186] 1 Photosensitive drum 2. Charge roller​ 4. Developing device 6 Cleaning device 9 Toner Cartridge 10 Process cartridge 45a Toner particles 45b Silica particles 45c lubricant particles 100 Image forming device T Initial toner filling T' Toner supply

Claims

1. A rotatable image carrier; a charging member for charging the surface of the image bearing member; a developing unit for supplying a developer to the surface of the image carrier charged by the charging member to form a developer image, the developing unit including a rotatable developing member that carries the developer on its surface, and a container that contains the developer to be supplied to the developing member; a supply container that is detachable from the developing unit, that contains a supply developer as the developer, and that can supply the supply developer to the container of the developing unit, The container of the new developing unit is filled in advance with a predetermined amount of initial developer, which is the developer, the initial developer and the replenishment developer contain at least toner particles, and a first external additive and a second external additive, The amount of the first external additive contained in the initial developer is defined as I1, the amount of the first external additive contained in the replenishment developer is defined as H1, the amount of the second external additive contained in the initial developer is defined as I2, and the amount of the second external additive contained in the replenishment developer is defined as H2, When the coverage rate of the first external additive in the initial developer measured by ESCA is defined as Wpa, the coverage rate of the first external additive in the replenishment developer is defined as Wta, the coverage rate of the second external additive in the initial developer is defined as Wpb, and the coverage rate of the second external additive in the replenishment developer is defined as Wtb, An image forming apparatus, comprising: an image forming unit that satisfies the following conditions: 0.9<H1 / I1<1.1, 0.9<H2 / I2<1.1, Wta<Wpa, and Wtb<Wpb.

2. a calculation unit that calculates an amount related to a printing rate of an image formed on a recording material in an image forming operation when the image forming operation is performed; a control unit that controls rotation of the image carrier and the developing member based on the amount calculated by the calculation unit, and controls a supply operation of supplying the developer from the developing member to a surface of the image carrier so as to be executable; The image forming apparatus according to claim 1, characterized in that the control unit controls the calculation unit to accumulate amounts related to the printing rate and calculate an average printing rate per sheet of recording material, and controls the supply operation to be executed when the average printing rate is smaller than a first threshold value.

3. 3. The image forming apparatus according to claim 1, wherein the first external additive is silica fine particles.

4. 3. The image forming apparatus according to claim 1, wherein the second external additive is a fatty acid metal salt.

Images