Image forming apparatus and supply container

Abstract

To prevent fusing of lubricant particles to a regulation member provided in a developing device in a configuration in which a supply container storing developer to be supplied to the developing device can be attached to and detached from the developing device for replacement.SOLUTION: An image forming apparatus 100 has a developing device 4, and a supply container 9 that is removably attached to the developing device 4 and stores developer T to be supplied to a storage part 42 of the developing device 4. A storage part 42 of a new developing device 4 is filled in advance with initial developer T that is a predetermined amount of developer. The initial developer T contains toner particles having a predetermined charging polarity. The toner particles in the initial developer T are externally added with lubricant particles having a charging polarity opposite to the predetermined charging polarity. Supply developer T' that is developer stored in the supply container 9 contains toner particles. The amount of lubricant particles externally added to the toner particles in the supply developer T' is smaller than the amount of lubricant particles externally added to the toner particles in the initial developer T.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 using an electrophotographic or electrostatic recording system, and to a supply container that contains developer to be supplied to a developing device of the image forming apparatus. [Background technology]

[0002] Conventionally, image forming apparatuses such as printers using an electrophotographic method record images as follows. First, the surface of a photoconductor serving as an image carrier is uniformly charged by a charging device, and the surface of the charged photoconductor is selectively exposed to light to form an electrostatic latent image on the photoconductor. Thereafter, a developing device supplies toner to the electrostatic latent image on the photoconductor to form a toner image on the photoconductor, and the toner image is transferred onto a recording material. After the toner image is transferred from the photoconductor to the recording material, the toner (transfer residual toner) remaining on the photoconductor is removed from the surface of the photoconductor by a cleaning device before the surface of the photoconductor is charged again by a charging device. The developing device generally has a developer carrier that carries the developer and transports it toward the photoconductor, and a regulating member that is provided in contact with the developer carrier, regulates the layer thickness of the developer carried by the developing roller, and charges the developer. A developing roller is often used as the developer carrier, and a developing blade is often used as the regulating member. Moreover, as a cleaning device, one that scrapes off the residual toner from the surface of the rotating photoconductor by using a cleaning member provided so as to come into contact with the surface of the photoconductor is widely used.

[0003] As a photoreceptor, organic photoreceptors are in widespread use due to the advantages of low cost and high productivity. An organic photoreceptor is configured by providing a photosensitive layer (organic photosensitive layer) using an organic material as a photoconductive substance (charge generating substance or charge transport substance) on a support. As an organic photoreceptor, photoreceptors having a laminated type photosensitive layer are mainstream due to the advantages of high sensitivity and diversity of material design. This photoreceptor is configured by laminating a charge generating layer containing a charge generating substance such as a photoconductive dye or a photoconductive pigment, and a charge transport layer containing a charge transport substance such as a photoconductive polymer or a photoconductive low molecular compound.

[0004] Electrical and mechanical external forces are directly applied to the surface of the photoreceptor in each process of charging, exposure, development, transfer, and cleaning. Therefore, the photoreceptor is required to have durability against these external forces. Specifically, the photoreceptor is required to have durability against scratches and wear on the surface of the photoreceptor caused by these external forces, that is, scratch resistance and wear resistance.

[0005] The following techniques are known as techniques for improving the scratch resistance and abrasion resistance of the surface of an organic photoreceptor. A photoreceptor is known in which a cured layer using a curable resin as a binder resin is used as a surface layer. A photoreceptor is known in which a charge transporting cured layer formed by curing and polymerizing a monomer having a carbon-carbon double bond and a charge transporting monomer having a carbon-carbon double bond with heat or light energy is used as a surface layer (Patent Document 1). A photoreceptor is known in which a charge transporting cured layer formed by curing and polymerizing a hole transporting compound having a chain polymerizable functional group in the same molecule with electron beam energy is used as a surface layer (Patent Document 2). A photoreceptor is known in which a wear-resistant protective layer (Over Coat Layer: OCL) is used on the surface layer of the photoreceptor (Patent Document 3).

[0006] On the other hand, it is known that improving the wear resistance of the surface of the photoconductor makes the surface of the photoconductor less likely to be scraped, and therefore increases the frictional force between the photoconductor and the cleaning member. This increase in frictional force increases the torque required to rotate the photoconductor, and there is a possibility that the device will become larger and the cost will increase in order to handle this load. In addition, if the cleaning member deteriorates due to this increase in frictional force, dirt will occur on the charging roller, which is widely used as a charging device, and this may lead to image defects.

[0007] Therefore, as one method of supplying a lubricant to the surface of a photoconductor, a method of adding an external additive (lubricant particles) having lubricity to a developer has been proposed (Patent Document 4). In particular, in the case of low printing, the surface of the photoconductor has more white areas (non-image areas) to which toner particles are not supplied, and the torque for rotating the photoconductor is likely to increase. Therefore, it is effective to externally add lubricant particles whose charging polarity is opposite to that of the toner particles to the toner particles. In this case, the lubricant particles that have fallen off the toner particles are supplied to the white areas (non-image areas) on the surface of the photoconductor. And, since the lubricant particles whose polarity is opposite to that of the toner particles are not transferred onto the recording material at the transfer section, they are easily supplied to the contact section between the photoconductor and the cleaning member. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 3194392 [Patent Document 2] JP 2000-66425 A [Patent Document 3] JP 2001-5207 A [Patent Document 4] JP 2017-198946 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, the lubricant particles, which have the polarity opposite to that of the toner particles, tend to move in the opposite direction to the toner particles in the developing device. This can cause the lubricant particles to fuse to the developing blade. If the lump of lubricant particles that fuses to the developing blade grows, it can disrupt the toner coat on the developing roller, resulting in image defects in the form of vertical streaks (streaks extending in the direction along the moving direction of the surface of the developing roller).

[0010] Here, the developing device may be configured as an independent unit, or as a part of a process cartridge, so as to be detachable from the main body of the image forming device. The process cartridge is a unit in which a photoconductor, a charging device acting on the photoconductor as a process means, a developing device, and a cleaning device are integrated into one structure, and is detachable from the main body of the image forming device. This configuration makes it easy to replenish toner and to replace and maintain various parts such as a photoconductor that has reached the end of its life. In addition, in order to respond to the extension of the life of the developing device or process cartridge, a method of replenishing toner from a toner cartridge detachable from the developing device or process cartridge may be adopted. For example, since the life of the photoconductor is being extended, only the toner container that is replaced frequently may be separated from the process cartridge and configured as a toner cartridge.

[0011] However, in the case of a configuration in which toner is supplied to a developing device from such a toner cartridge, if the toner cartridge is repeatedly replaced for one developing device, a large amount of lubricant particles will be supplied to the developing blade, which may cause the lubricant particles to melt and adhere to the developing blade, which may hinder the longevity of the developing device and the process cartridge.

[0012] Therefore, an object of the present invention is to suppress the adhesion of lubricant particles to a regulating member provided in a developing device in a configuration in which a supply container containing developer to be replenished to the developing device can be attached and detached to the developing device and replaced. [Means for solving the problem]

[0013] The above object is achieved by the image forming apparatus and the supply container according to the present invention. In summary, the present invention provides a developing device that forms a developer image by supplying a developer to the surface of the image carrier charged by the charging means, the developing device including a rotatable image carrier, a charging means for charging the surface of the image carrier, a rotatable developing member that carries the developer and transports it toward the image carrier, a regulating member that contacts the developing member to regulate the amount of developer on the developing member, and a container that contains the developer supplied to the developing member, a cleaning member that contacts the surface of the image carrier to remove the developer from the surface of the image carrier, and a supply container that is detachable from the developing device and contains the developer to be replenished to the container of the developing device, and a developing device that is detachable from the developing device and contains the developer to be replenished to the container of the developing device, the developing device being provided with a cleaning member that contacts the surface of the image carrier to remove the developer from the cleaning member, and a supply container that is detachable from the developing device and contains the developer to be replenished to the container of the developing device, the developing device being provided with a cleaning member that contacts the surface of the image carrier to remove the developer from the cleaning member, and ... and a supply container that can be removed from the developing device and replaced after developer is replenished to the storage section of the new developing device, wherein the storage section of the new developing device is pre-filled with a predetermined amount of initial developer, the initial developer containing toner particles having a predetermined charge polarity, the toner particles of the initial developer having lubricant particles having a charge polarity opposite to the predetermined polarity externally added, the supply developer, which is the developer contained in the supply container, containing the toner particles, and the amount of the lubricant particles externally added to the toner particles in the supply developer is less than the amount of the lubricant particles externally added to the toner particles in the initial developer.

[0014] According to another aspect of the present invention, a developing device includes a rotatable image carrier, charging means for charging the surface of the image carrier, and a developer for supplying developer to the surface of the image carrier charged by the charging means to form a developer image, the developing device including a rotatable developing member for carrying and transporting the developer toward the image carrier, a regulating member for contacting the developing member to regulate the amount of developer on the developing member, and a container for accommodating the developer supplied to the developing member, and a cleaning member for contacting the surface of the image carrier to remove the developer from the surface of the image carrier, the container being pre-filled with a predetermined amount of initial developer, which is a new developing device. an image forming apparatus is provided, in which the developing device is filled with developer in the storage section, and the developing device can be continuously used even after the predetermined amount of developer has been consumed by replenishing developer in the storage section; the initial developer contains toner particles having a predetermined charge polarity, and the toner particles of the initial developer have lubricant particles having a charge polarity opposite to the predetermined polarity externally added thereto; a replenishing developer which is a developer replenishing to the developing device contains the toner particles, and the amount of the lubricant particles externally added to the toner particles in the replenishing developer is less than the amount of the lubricant particles externally added to the toner particles in the initial developer.

[0015] According to another aspect of the present invention, a developing device for forming a developer image by supplying a developer to the surface of the image carrier charged by the charging means, the developing device includes a rotatable image carrier, a charging means for charging the surface of the image carrier, and the developing device is provided with a rotatable developing member for carrying and transporting the developer toward the image carrier, a regulating member for contacting the developing member to regulate an amount of developer on the developing member, and a container for accommodating the developer supplied to the developing member, and a cleaning member for contacting the surface of the image carrier to remove the developer from the surface of the image carrier, the container being pre-filled with a predetermined amount of initial developer, and the developing device is configured to be turned on when the container is turned on and the developer is replenished. By doing so, the initial developer can be continuously used even after the specified amount of developer has been consumed, the initial developer contains toner particles having a specified charge polarity, and the toner particles of the initial developer have lubricant particles having a charge polarity opposite to the specified polarity externally added thereto. The initial developer contains toner particles having a specified charge polarity, and the toner particles of the initial developer have lubricant particles externally added thereto. The initial developer is detachable from the developing device of an image forming apparatus, and a supply container is provided that contains developer to be replenished to the storage section of the developing device, the supply container being the developer contained in the supply container contains the toner particles, and the amount of the lubricant particles externally added relative to the toner particles in the supply developer is less than the amount of the lubricant particles externally added relative to the toner particles in the initial developer. Effect of the Invention

[0016] According to the present invention, in a configuration in which a toner supply container containing toner to be replenished to a developing device can be attached and detached to the developing device and replaced, it is possible to suppress the adhesion of lubricant particles to a regulating member provided in the developing device. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a process cartridge and a toner cartridge. [Diagram 3]FIG. 2 is a schematic block diagram of a control configuration of the image forming apparatus. [Figure 4] FIG. 2 is a schematic diagram of a toner. [Diagram 5] 11 is a graph showing the change in the amount of toner in a toner cartridge in an evaluation experiment. [Figure 6] FIG. 11 is a graph showing a change in drum torque in an evaluation experiment. [Figure 7] FIG. 2 is a schematic diagram of a surface modification device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 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.

[0019] [Embodiment 1] <Overall configuration and operation of 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.

[0020] 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 .

[0021] 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. An exposure device (scanner unit) 3 serving as an exposure means is provided above the process cartridge 10 in the apparatus main body 110.

[0022] 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.

[0023] 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. 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.

[0024] 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.

[0025] 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.

[0026] <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.

[0027] 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.

[0028] The drum unit 11 has 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. The charging roller 2 and a cleaning member 63 of the cleaning device 6 are in contact with the surface (outer circumferential surface) of the photosensitive drum 1. The photosensitive drum 1 is driven to rotate 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.

[0029] 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.

[0030] 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.

[0031] 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. Furthermore, a stirring member 47 is rotatably attached to the developing container 41 .

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The stirring member 47 is disposed in the toner storage chamber 42, and stirs the toner T stored in the toner storage chamber 42 while transporting the toner T toward the supply roller 44. The stirring member 47 is configured to have an 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 apparatus main body 110.

[0037] The photosensitive drum 1 and the rotating members of the developing device 4 (the developing roller 43, the supply roller 44, and the stirring member 47) may share a driving source.

[0038] 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.

[0039] 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.

[0040] <Toner cartridge> Next, the toner cartridge 9 in this embodiment will be further described.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] <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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] <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.

[0053] 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.

[0054] 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 toner 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The usage history values ​​of the developing device 4 (toner consumption amount, toner supply amount, remaining toner amount) are stored in the memory MP.

[0059] <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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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, when the amount of toner in the toner cartridge 9 has decreased to a predetermined amount and the toner cartridge 9 is unable to sufficiently replenish the toner to the developing device 4 to replace the toner consumed by the developing device 4, the toner cartridge 9 needs to be replaced. Specifically, the amount of toner in a new toner cartridge 9 can be set to 100% remaining toner, and the state in which the amount of toner in the toner cartridge 9 has decreased to a predetermined threshold value can be set to 0% remaining toner. In this embodiment, 0% remaining toner 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 can also be set to 0% remaining toner (toner out).

[0064] The usage history value (toner supply amount, remaining toner amount) of the toner cartridge 9 is stored in the memory MT. The usage history value (toner supply amount, remaining toner amount) of the toner cartridge 9 may be further stored in the memory MP. In this embodiment, the control unit 120 executes a process of notifying the operator that the toner cartridge 9 is out of toner when the remaining toner amount indicated by the usage history value of the toner cartridge 9 reaches a predetermined threshold value. The control unit 120 can perform each of the above-mentioned notifications to the operator by displaying 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 or the like on the display unit. For example, the notification may be by a warning sound or voice generated by 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 notification of information to the operator may be performed on 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, etc. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0092] 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.

[0093] 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.

[0094] (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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] (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.

[0103] The conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] <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.

[0111] 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.

[0112] 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)") is different from the initial filled toner T in the amount of positively charged lubricant particles 45c externally added to the toner particles 45a. In this embodiment, the other points of the suppliment toner T' are the same as those of the initial filled toner T.

[0113] (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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.).

[0119] 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.

[0120] (External additives) -Lubricant particles- In this embodiment, positively charged lubricant particles 45c are externally added to the toner particles 45a. 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 adhering to the surface of the photosensitive drum 1 easily reach the cleaning member 63. 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.

[0121] 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.

[0122] 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.

[0123] The metal is preferably a divalent metal. Examples of the metal include magnesium, calcium, aluminum, barium, and zinc. Among these metals, zinc is preferred.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] Here, the average particle size of the lubricant particles can be measured, for example, by the following method. Each primary particle of the lubricant particles is observed and an image is 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 particles. Then, the 50% diameter (D50) in the cumulative frequency based on volume of the obtained circle-equivalent diameter is defined 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 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.

[0128] -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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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. Circularity (100 / SF2) = 4π × (A / I 2 ) [In the formula, I represents the perimeter of a primary particle on an image, and A represents the projected area of ​​the primary particle.]

[0136] 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.

[0137] -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 positively charged lubricant particles 45c to toner particles 45a. The details are as described in JP 2016-38591 A.

[0138] Briefly, as shown in FIG. 7, 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 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 attaching 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.

[0139] <Initial toner filling and replenishment toner> As described above, the lubricant particles 45c, which have the opposite polarity to the toner particles 45a, tend to move in the opposite direction to the toner particles 45a in the developing device 4. Therefore, the lubricant particles 45c may fuse to the developing blade 46. In particular, in the case of a configuration in which the toner T is supplied to the developing device 4 from the toner cartridge 9, when the toner cartridge 9 is repeatedly replaced for one developing device 4, many lubricant particles 45c are supplied to the developing blade 46. As a result, the lubricant particles 45c are likely to fuse to the developing blade 46. When a mass of the lubricant particles 45c fused to the developing blade 46 grows, it may disturb the toner coat on the developing roller 43, and may cause a vertical streak-like (streak-like extending in the direction along the moving direction of the surface of the developing roller 43) image defect (hereinafter also referred to as "development streak"). As a result, it may become a factor that hinders the long life of the developing device 4 and the process cartridge 10.

[0140] Therefore, in this embodiment, the amount of positively charged lubricant particles 45c added to the toner particles 45a of the replenishment toner T' contained in the toner cartridge 9 is made smaller than the amount of positively charged lubricant particles 45c added to the toner particles 45a of the initial filling toner T that is filled in advance in a new developing device 4 (process cartridge 10). The amount of positively charged lubricant particles 45c added to the toner particles 45a can be expressed as the mass % of the positively charged lubricant particles 45c with respect to the total mass of the toner particles 45a. The amount of positively charged lubricant particles added to the toner particles 45a of the replenishment toner T' contained in the toner cartridge 9 may be 0 mass % (i.e., the positively charged lubricant particles 45c may not be added to the toner particles 45a of the replenishment toner T').

[0141] This makes it possible to prevent the lubricant particles 45c from fusing to the developing blade 46 in a configuration in which the toner cartridge 9 is detachably attached to the developing device 4 for replacement.

[0142] <Evaluation experiment> Evaluation experiments were carried out to confirm the effects of this embodiment for examples (Examples 1 and 2) according to this embodiment and comparative examples (Comparative Examples 1 and 2) for comparison with this embodiment.

[0143] 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 additives (silica particles 45b, positively charged lubricant particles 45c) added, and the rotation speed of the tip of the blade of the surface modification device 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 was treated at the blade tip circumferential speed and time shown in Table 1. Next, silica particles (large silica particles) 45b and positively charged lubricant particles 45c (if added) were added as shown in Table 1, and the surface modification device was treated at the blade tip circumferential speed and time shown in Table 1. As shown in Table 1, P-1 and P-2 were prepared as the initial filling toner T, and T-1, T-2, and T-3 were prepared as the refill toner T'.

[0144] Table 2 shows the combinations of the initial filling toner T (P-1, P-2) and the refill toner T' (T-1, T-2) used in each of the examples (Examples 1 and 2) and the comparative examples (Comparative Examples 1 and 2). In each example, the same toner particles 45a, silica particles 45b, and positively charged lubricant particles 45c were used. Specifically, non-magnetic toner particles (weight average particle size 7 μm) produced by a suspension polymerization method were used as the toner particles 45a. Furthermore, monodisperse and spherical sol-gel silica particles (two types of particles with different primary particle sizes) were used as the silica particles 45b. Furthermore, zinc stearate particles (average particle size 1 μm) were used as the positively charged lubricant particles 45c.

[0145] [Table 1]

[0146] [Table 2]

[0147] A new process cartridge 10 is filled with 150 g of initially filled toner T, and a new toner cartridge 9 is filled with 600 g of replenishment toner T'. The process cartridge 10 and the toner cartridge 9, which are the combinations of the initially filled toner T and replenishment toner T' shown in Table 2, were mounted on the image forming apparatus 100, and printing was performed up to 100K (100,000). The printing was performed by adjusting the printing rate so as to show the transition of the toner amount in the toner cartridge 9 with respect to the number of printed sheets shown in FIG. 5. In addition, the torque applied to the driving source of the photosensitive drum 1 when printing was performed under these conditions (herein also referred to as "drum torque") was measured. The drum torque was measured based on information showing the relationship between the driving current flowing through the driving source and the drum torque, which was previously obtained. FIG. 6 shows the transition of the drum torque with respect to the number of printed sheets. In addition, Table 3 shows the evaluation results of the occurrence of development streaks (occurrence of fusion of the lubricant particles 45c to the developing blade 46) and the occurrence of dirt on the charging roller 2 in each example.

[0148] [Table 3]

[0149] As shown in FIG. 5, three toner cartridges 9 were used to print up to 100K sheets. As shown in FIG. 6, in Examples 1 and 2 and Comparative Example 1, the drum torque was sufficiently reduced and stabilized by the time the period (Tp in FIG. 6) for initially using the toner T filled in the process cartridge 10 had elapsed. This is considered to be because, by performing printing to a certain extent, the surface of the photosensitive drum 1 was finely scratched by the paper or silica particles 45b while the positively charged lubricant particles 45c were being supplied to the cleaning member 63, and the friction coefficient of the surface of the photosensitive drum 1 was reduced. On the other hand, in Comparative Example 2, since the initial filling toner T (P-2) did not contain the positively charged lubricant particles 45c, the drum torque increased immediately after the start of the printing experiment, and printing became impossible due to an abnormality in the drum torque before the period Tp had elapsed.

[0150] In addition, in Examples 1 and 2, even after printing 100K sheets, no stains on the surface of the charging roller 2 that would cause problems in the image were observed, and it was confirmed that the charging roller 2 was in a sufficiently usable condition. On the other hand, in Comparative Example 1, the surface of the charging roller 2 was stained in a streaky manner (stripe-like streaks extending in the direction along the moving direction of the surface of the charging roller 2), and thus streaky stains were observed on the image due to insufficient charging (uneven charging) of the surface of the photosensitive drum 1. This is considered to be due to the occurrence of fogging (a phenomenon in which toner T with insufficient charge adheres to non-image areas on the surface of the photosensitive drum 1) caused by the occurrence of development streaks (fusion of lubricant particles 45c to the development blade 46) described later.

[0151] In addition, when the timing of occurrence of development streaks was checked, development streaks occurred on the image from about 40K sheets in Comparative Example 1. In contrast, development streaks did not occur on the image until 100K sheets in Examples 1 and 2. In addition, when the process cartridge 10 was disassembled and the rubbing portion of the development blade 46 with the development roller 43 was checked, slight fusion of the lubricant particles 45c occurred in Example 1, but fusion of the lubricant particles 45c was hardly confirmed in Example 2. However, in Example 2, since the supply toner T' (T-2) does not contain positively charged lubricant particles 45c, contamination due to external additives on the surface of the charging roller 2, which is thought to be due to deterioration of the cleaning member 63, was observed, although it was not at a level that caused a problem in the image.

[0152] In this way, the amount of the positively charged lubricant particles 45c added to the toner particles 45a of the replenishment toner T' contained in the toner cartridge 9 is less than the amount of the positively charged lubricant particles 45c added to the toner particles 45a of the initial filled toner T pre-filled in a new developing device 4 (process cartridge 10). This makes it possible to suppress the fusion of the lubricant particles 45c to the developing blade 46 while suppressing deterioration of the cleaning member 63.

[0153] The amount of the positively charged lubricant particles 45c externally added to the toner particles 45a of the replenishment toner T' contained in the toner cartridge 9 can be appropriately adjusted according to the configuration of the developing device 4 and the drum unit 11. Even if the replenishment toner T' does not contain the positively charged lubricant particles 45c, the amount of the positively charged lubricant particles 45c externally added in the initial filling toner T is preferably an amount that allows the drum torque to be sufficiently reduced and stabilized before a predetermined amount of the toner T of the initial filling toner T is consumed. As a result, even if the replenishment toner T' does not contain the positively charged lubricant particles 45c, the drum torque will be sufficiently reduced and stabilized before a predetermined amount of the toner T of the initial filling toner T is consumed, and thereafter, the supply of the positively charged lubricant particles 45c is substantially unnecessary. However, in order to stabilize the drum torque in a sufficiently reduced state for a longer period of time, it may be preferable to contain the positively charged lubricant particles 45c in the replenishment toner T' to the extent that the fusion of the lubricant particles 45c to the development blade 46 can be sufficiently suppressed. For example, in the configuration of this embodiment, the amount (by mass %) of the positively charged lubricant particles 45c added externally in the supply toner T' is preferably greater than 0% by mass and approximately 1 / 2 or less of the amount (by mass %) of the positively charged lubricant particles 45c added externally in the initially filled toner T, and more preferably approximately 1 / 3 or less.

[0154] Thus, in this embodiment, the image forming apparatus 100 includes a rotatable image carrier (photosensitive drum) 1, a charging means (charging roller) 2 for charging the surface of the image carrier 1, and a developing device 4 for supplying developer T to the surface of the image carrier 1 charged by the charging means 2 to form a developer image, the developing device 4 including a rotatable developing member (developing roller) 43 for carrying the developer T and transporting it toward the image carrier 1, a regulating member (developing blade) 46 for contacting the developing member 43 to regulate the amount of developer T on the developing member, and a container 42 for accommodating the developer T to be supplied to the developing member 43, a cleaning member 63 for contacting the surface of the image carrier 1 to remove the developer T from the surface of the image carrier 1, and a replenishment roller 44 for replenishment of the developer T to the container 42 of the developing device 4. The toner cartridge 9 includes a supply container 9 that can be removed from the developing device 4 and replaced after the developer T is supplied from the supply container 9 to the storage section 42 of the developing device 4. The storage section 42 of the new developing device 4 is filled in advance with a predetermined amount of initial developer T, which is a developer. The initial developer T contains toner particles 45a having a predetermined charge polarity, and lubricant particles 45c having a charge polarity opposite to the predetermined polarity are externally added to the toner particles 45a of the initial developer T. The supply developer T', which is a developer contained in the supply container 9, contains toner particles 45a, and the amount of lubricant particles 45c externally added to the toner particles 45a in the supply developer T' is less than the amount of lubricant particles 45c externally added to the toner particles 45a in the supply developer T'. Here, the lubricant particles 45c may not be externally added to the toner particles 45a of the supply developer T'. In this embodiment, the lubricant particles 45c are fatty acid metal salts. In this embodiment, the image carrier 1 has a protective layer on the outermost surface. In this embodiment, the protective layer is formed using acrylic resin. In this embodiment, the amount of replenishment developer T' contained in a new replenishment container 9 is greater than the above-mentioned predetermined amount of initial developer T. In this embodiment, the image forming apparatus 100 has a detachable unit (process cartridge) 10 including the image carrier 1 and the developing device 4.

[0155] As described above, according to this embodiment, for example, in a configuration using a long-life photosensitive drum 1, it is possible to achieve both a reduction in initial drum torque and suppression of fusion of the lubricant particles 45c to the developing blade 46. This makes it possible to suppress stains on the charging roller 2 caused by deterioration of the cleaning member 63 over a long period of time, while suppressing development streaks caused by fusion of the lubricant particles 45c to the developing blade 46. Thus, according to this embodiment, in a configuration in which a toner supply container containing toner to be replenished to the developing device is detachable from the developing device and replaceable, it is possible to suppress fusion of the lubricant particles to the regulating member.

[0156] [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.

[0157] 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.

[0158] In the above embodiment, the developing device uses a contact development method in which the image carrier and the developer carrier 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 image carrier and the developer carrier 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, but may be a two-component developer or a magnetic one-component developer.

[0159] At least one of the initial toner and the replenishment toner may contain lubricant particles whose charging polarity is the same as that of the toner particles (negative in the above embodiment). That is, for the purpose of further reducing the frictional force between the photoconductor and the cleaning member, lubricant particles having the same polarity as the toner particles can be externally added to the toner particles so that the lubricant particles adhere to the printing portion (image portion) on the surface of the photoconductor. Examples of negatively charged lubricant particles include fluororesin particles, silicone resin, inorganic particles, and wax resin particles. Examples of fluororesin particles include particles of polytetrafluoroethylene (PTFE, "tetrafluoroethylene resin"), perfluoroalkoxy fluororesin, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, and tetrafluoroethylene-perfluoroalkoxy ethylene copolymer. Among these, polytetrafluoroethylene (PTFE) is preferred. The amount (mass%) of external additives to toner particles having the same charge polarity as the charge polarity of the toner particles (negative polarity in the above-mentioned embodiment) may be the same or different between the initially filled toner and the replenishment toner. If the amount (mass%) of external additives to toner particles having the opposite charge polarity to the charge polarity of the toner particles (positive polarity in the above-mentioned embodiment) is less in the replenishment toner than in the initially filled toner, the same effect as in the above-mentioned embodiment can be obtained. [Explanation of symbols]

[0160] 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 63 Cleaning materials 100 Image forming device T toner, initial fill toner T' Toner supply

Claims

1. A rotatable image carrier; A charging means for charging the surface of the image bearing member; a developing device that supplies a developer to the surface of the image carrier that has been charged by the charging means to form a developer image, the developing device including: a rotatable developing member that carries the developer and transports it toward the image carrier; a regulating member that contacts the developing member to regulate an amount of the developer on the developing member; and a container that contains the developer to be supplied to the developing member; a cleaning member that comes into contact with the surface of the image carrier to remove developer from the surface of the image carrier; a supply container that is detachable from the developing device and contains a developer to be replenished to the container of the developing device, and that can be removed from the developing device and replaced after the developer is replenished from the supply container to the container of the developing device, The container of the new developing device is filled in advance with a predetermined amount of initial developer, which is an initial developer. the initial developer contains toner particles having a predetermined charge polarity; the toner particles of the initial developer are externally added with lubricant particles having a charge polarity opposite to the predetermined polarity; the developer contained in the supply container contains the toner particles; an amount of the lubricant particles added to the toner particles in the supply developer being smaller than an amount of the lubricant particles added to the toner particles in the initial developer;

2. 2. The image forming apparatus according to claim 1, wherein the lubricant particles are not externally added to the toner particles of the supply developer.

3. 3. The image forming apparatus according to claim 1, wherein the lubricant particles are a fatty acid metal salt.

4. 3. The image forming apparatus according to claim 1, wherein the image carrier has a protective layer on the outermost surface thereof.

5. 5. The image forming apparatus according to claim 4, wherein the protective layer is made of an acrylic resin.

6. 3. The image forming apparatus according to claim 1, wherein the amount of the supply developer contained in the new supply container is greater than the predetermined amount of the initial developer.

7. 3. The image forming apparatus according to claim 1, wherein a unit including said image carrier and said developing device is detachable.

8. A rotatable image carrier; A charging means for charging the surface of the image bearing member; a developing device that supplies a developer to the surface of the image carrier that has been charged by the charging means to form a developer image, the developing device including: a rotatable developing member that carries the developer and transports it toward the image carrier; a regulating member that contacts the developing member to regulate an amount of the developer on the developing member; and a container that contains the developer to be supplied to the developing member; a cleaning member that comes into contact with the surface of the image carrier to remove developer from the surface of the image carrier; The container of the new developing device is filled in advance with a predetermined amount of initial developer, which is an initial developer. the developing device can be continuously used even after the predetermined amount of developer is consumed by replenishing the developer in the container; the initial developer contains toner particles having a predetermined charge polarity; the toner particles of the initial developer are externally added with lubricant particles having a charge polarity opposite to the predetermined polarity; a supply developer which is a developer supplied to the developing device, contains the toner particles, an amount of the lubricant particles added to the toner particles in the supply developer being smaller than an amount of the lubricant particles added to the toner particles in the initial developer;

9. 9. The image forming apparatus according to claim 8, wherein the lubricant particles are not externally added to the toner particles of the supply developer.

10. A rotatable image carrier; A charging means for charging the surface of the image bearing member; a developing device that supplies a developer to the surface of the image carrier that has been charged by the charging means to form a developer image, the developing device including: a rotatable developing member that carries the developer and transports it toward the image carrier; a regulating member that contacts the developing member to regulate an amount of the developer on the developing member; and a container that contains the developer to be supplied to the developing member; a cleaning member that comes into contact with the surface of the image carrier to remove developer from the surface of the image carrier; The container of the new developing device is filled in advance with a predetermined amount of initial developer, which is an initial developer. the developing device can be continuously used even after the predetermined amount of developer is consumed by replenishing the developer in the container; the initial developer contains toner particles having a predetermined charge polarity; a supply container detachably attached to the developing device of an image forming apparatus, the supply container containing a developer to be supplied to the container section of the developing device, the supply container comprising: a lubricant particle having a charge polarity opposite to the predetermined polarity and externally added to the toner particles of the initial developer; the lubricant particle having a charge polarity opposite to the predetermined polarity; the developer contained in the supply container contains the toner particles; a lubricant particle externally added to the toner particles in the supply developer in an amount smaller than a lubricant particle externally added to the toner particles in the initial developer;

11. 11. The replenishing container according to claim 10, wherein the lubricant particles are not externally added to the toner particles of the replenishing developer.

Images