Process cartridge

Abstract

The present invention uses a cartridge that comprises: a photosensitive drum; a development roller; a supply roller; a development chamber; a development blade that includes an elastic blade and a support section; and an accommodation section for a toner that has a particle diameter R. The accommodation section and the development chamber are in mutual communication. A site of contact between the development blade and the development roller is below a horizontal line that passes through the center of the axis of rotation of the development roller. Fluorine is present in the interior of hydrotalcite particles of an external additive of the toner. If, in a nip of the elastic blade and the development roller, an end section on the upstream side in the direction of rotation of the development roller is a point D, the furthest free-end side of the elastic blade is a point B, a point where a line perpendicular to the point B intersects the development roller is a point E, a point on the furthest free-end side among points on the surface of the elastic blade at a distance R from the surface of the development roller is a point F, and a point on a line BE at the distance R from the surface of the development roller is a point G, then the distance between the points G and F is at least R.

Description

Process cartridge

[0001] The present invention relates to a process cartridge.

[0002] In image forming devices such as printers that use an electrophotographic image formation method (electrophotographic process), an electrophotographic photoreceptor (hereinafter referred to as "photoreceptor") serving as an image carrier is uniformly charged and selectively exposed to light to form an electrostatic image on the photoreceptor. The electrostatic image formed on the photoreceptor is visualized as a toner image using toner as a developer. The toner image formed on the photoreceptor is then transferred to a recording material such as recording paper or a plastic sheet, and the toner image transferred to the recording material is fixed to the recording material by applying heat and pressure to the toner image, thereby completing image recording.

[0003] Such image forming apparatuses generally require the replenishment of developer and the maintenance of various process means. To facilitate the replenishment of developer and the maintenance of various process means, a process cartridge has been put into practical use, in which the photosensitive member, charging means, developing means, cleaning means, etc. are integrated into a frame to form a cartridge that can be detachably attached to the main body of the image forming apparatus. The process cartridge system makes it possible to provide an image forming apparatus with excellent usability.

[0004] In recent years, color image forming apparatuses that form color images using multiple color developers have become popular. A known color image forming apparatus is a so-called in-line type image forming apparatus in which photoconductors corresponding to the image forming operations using multiple color developers are arranged in a row along the direction of movement of the surface of a transfer medium onto which a toner image is transferred. Some in-line type color image forming apparatuses have multiple photoconductors arranged in a row in a direction (e.g., horizontal) that intersects with the vertical direction (the direction of gravity). The in-line type is a preferred image forming method because it can easily meet demands for faster image formation and for deployment in multifunction printers.

[0005] Further, there is an image forming apparatus in which a photosensitive member is disposed below an intermediate transfer member as a transfer target member, or below a recording material carrier that conveys a recording material as a transfer target member (Japanese Patent Laid-Open No. 2011-253203).

[0006] When the photosensitive member is disposed below the intermediate transfer member or recording material carrier, the fixing device and the developing device (or the exposure device) can be disposed at separate positions within the image forming apparatus body with the intermediate transfer member or the recording material carrier sandwiched between them, which has the advantage that the developing device (or the exposure device) is less susceptible to the heat of the fixing device.

[0007] JP 2011-253203 A

[0008] An object of the present invention is to provide a cartridge that is an improvement over conventional cartridges.

[0009] The present invention has the following configuration: That is, a process cartridge that can be mounted in an image forming apparatus, comprising a photosensitive drum as an image carrier, a developing roller for developing a toner image on the photosensitive drum, a supply roller for supplying toner to the developing roller, a developing chamber having a support portion for axially supporting the developing roller and the supply roller, a developing blade for regulating the layer thickness of the toner on the developing roller, toner containing toner particles having a volume average particle size R and an external additive, and a toner storage portion for storing the toner, the toner storage portion is configured to communicate with the developing chamber via a communication port, the direction of movement of the surface of the developing roller is opposite to the direction of movement of the surface of the supply roller at the position of contact with the supply roller, in a cross section of the process cartridge in a plane perpendicular to the rotational axis of the developing roller when mounted in the main body of the image forming apparatus, the point where the developing blade contacts the developing roller is vertically below a horizontal line H1 passing through the center of the rotational axis of the developing roller, and the process cartridge has a drive force receiving portion, a first driving force transmission section for transmitting the driving force from the driving force receiving section to the supply roller; a second driving force transmission section provided on the supply roller for transmitting the driving force received by the first driving force transmission section to the developing roller; and a third driving force transmission section provided on the developing roller for transmitting the driving force from the second driving force transmission section to the developing roller, wherein the toner has hydrotalcite particles as the external additive, and in a line analysis in a STEM-EDS mapping analysis of the toner, fluorine is present inside the hydrotalcite particles, the developing blade is made of a plate-shaped metallic elastic blade and a blade support section for supporting the elastic blade, and in a cross section of the process cartridge taken on a plane perpendicular to the rotation axis of the developing roller, the elastic blade is in contact with the developing roller, forming a nip N1, and a point on the elastic blade at the upstream end in the nip N1 in the rotation direction of the developing roller is defined as point D, and a point on the elastic blade that is closest to the free end side and nearest to the surface of the developing roller is defined as point B, A point E is defined as a point where a perpendicular line drawn from point B to the surface of the developing roller intersects with the surface of the developing roller.The process cartridge is characterized in that, among the points on the surface of the elastic blade at a distance R from the surface of the developing roller, there is a point F that is closest to the free end of the elastic blade, and when a point on a line BE at a distance R from the surface of the developing roller is G, the distance GF is equal to or greater than R. The present invention also has the following configuration. That is, a process cartridge that can be mounted in an image forming apparatus comprises a photosensitive drum as an image carrier, a developing roller for developing a toner image on the photosensitive drum, a supply roller for supplying toner to the developing roller, a developing chamber having a support portion for axially supporting the developing roller and the supply roller, a developing blade for regulating the layer thickness of the toner on the developing roller, a toner containing toner particles having a volume average particle size R and an external additive, and a toner containing portion for containing the toner, the toner containing portion is configured to communicate with the developing chamber via a communication port, the direction of movement of the surface of the developing roller is opposite to the direction of movement of the surface of the supply roller at the position of contact with the supply roller, the developing blade comprises a plate-shaped elastic blade made of metal and a blade support portion for supporting the elastic blade, and in a cross section of the process cartridge in a plane perpendicular to the rotation axis of the developing roller, a first driving force transmitting section for transmitting a driving force from the driving force receiving section to the supply roller; a second driving force transmitting section provided on the supply roller for transmitting the driving force received by the first driving force transmitting section to the developing roller; and a third driving force transmitting section provided on the developing roller for transmitting the driving force from the second driving force transmitting section to the developing roller, wherein the toner contains hydrotalcite particles as the external additive,In a line analysis in the STEM-EDS mapping analysis of the toner, fluorine is present inside the hydrotalcite particles, and in a cross section of the process cartridge in a plane perpendicular to the rotation axis of the developing roller, the elastic blade is in contact with the developing roller, forming a nip N1, and the point on the elastic blade at the upstream end in the direction of rotation of the developing roller at nip N1 is defined as point D, the point on the elastic blade that is closest to the free end and closest to the surface of the developing roller is defined as point B, and the point at which a perpendicular line drawn from point B to the surface of the developing roller intersects with the surface of the developing roller is defined as point E, and there is a point on the surface of the elastic blade that is closest to the free end of the elastic blade at a distance R from the surface of the developing roller, and when G is the point on a line BE that is closest to the distance R from the surface of the developing roller, the distance GF is equal to or greater than R.

[0010] As described above, according to the present invention, it is possible to provide a cartridge that is a further development of conventional cartridges.

[0011] Schematic cross-sectional view of an image forming apparatus according to an embodiment to which the present invention can be applied. Schematic cross-sectional view of a process cartridge according to an embodiment to which the present invention can be applied. Conceptual cross-sectional view in the short direction of a developing blade according to an embodiment to which the present invention can be applied. (a) is a conceptual cross-sectional view illustrating the contact state between a developing blade and a developing roller according to an embodiment to which the present invention can be applied; (b) is a conceptual cross-sectional view illustrating the contact state between a developing blade and a developing roller according to a comparative example of the present invention. Figures explaining a method of inputting drive power to a toner supply roller according to an embodiment to which the present invention can be applied. Figures showing the movement of toner within a developing device according to an embodiment to which the present invention can be applied. Figures explaining the positional relationship between the inner wall of a developing chamber and the support end of a developing blade according to an embodiment to which the present invention can be applied. (a) and (b) are conceptual cross-sectional views of the contact portion between a developing roller and a developing blade to explain the movement of toner regulated by the developing blade according to an embodiment to which the present invention can be applied. (a)-(c) are schematic views of line analysis of external additives. Conceptual cross-sectional view in the short direction of an image blade when the tip of the developing blade is bent in a modified embodiment to which the present invention can be applied.

[0012] The developing device, process cartridge, and image forming apparatus according to the present invention will be described in more detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components described in this embodiment are not intended to limit the scope of the present invention. Furthermore, the materials, shapes, and other aspects of components described once in the following description will remain the same in subsequent descriptions unless otherwise specified. Well-known or publicly known technologies in the relevant technical field can be applied to configurations and processes not specifically illustrated or described. Furthermore, duplicated descriptions may be omitted.

[0013] <Example> [Image Forming Apparatus] Figure 1 is a diagram showing the schematic configuration of an image forming apparatus 100 of this example, placed stationary on a horizontal surface, as in actual use. The image forming apparatus 100 of this example is an inline full-color laser printer employing an intermediate transfer method. As shown in Figure 1, four removable process cartridges 70 (70Y, 70M, 70C, and 70K) are mounted using mounting members (not shown). The upstream side of the process cartridges 70 in the mounting direction of the image forming apparatus 100 is defined as the front side, and the downstream side of the mounting direction is defined as the rear side.

[0014] Each process cartridge 70 includes an electrophotographic photosensitive drum (hereinafter referred to as photosensitive drum) 1 (1a, 1b, 1c, 1d). In each process cartridge 70, process means such as charging rollers 2 (2a, 2b, 2c, 2d), developing rollers 25 (25a, 25b, 25c, 25d), and cleaning members 6 (6a, 6b, 6c, 6d) are integrally arranged around the photosensitive drum 1. The charging roller 2 uniformly charges the surface of the photosensitive drum 1. In this embodiment, it is negatively charged. The developing roller 25 develops the latent image formed on the photosensitive drum 1 with developer (hereinafter referred to as toner) to make it visible. In this embodiment, the normal polarity of the toner is negative. The cleaning member 6 removes any toner remaining on the photosensitive drum 1 after the toner image formed on the photosensitive drum 1 is transferred to a recording medium. The detailed configurations and positional relationships of the photosensitive drum 1, charging roller 2, developing roller 25, and cleaning member 6 will be described later with reference to FIG.

[0015] Further, below the process cartridge 70 in the direction of gravity, a scanner unit 3 is provided for selectively exposing the photosensitive drum 1 based on image information and forming a latent image on the photosensitive drum 1 .

[0016] A cassette 17 containing a recording medium S is attached to the bottom of the apparatus main body 100a. A recording medium transport means is provided so that the recording medium S passes through a secondary transfer roller 69 and a fixing unit 74 and is transported to the upper part of the apparatus main body 100a. An intermediate transfer unit 5 is provided above the process cartridges 70 (70Y, 70M, 70C, 70K) as an intermediate transfer means for transferring the toner images formed on the photosensitive drums 1 (1a, 1b, 1c, 1d). The intermediate transfer unit 5 has a drive roller 56, a driven roller 57, primary transfer rollers 58 (58a, 58b, 58c, 58d) facing the photosensitive drums 1 of each color, and an opposing roller 59 facing the secondary transfer roller 69, and a transfer belt 50 is stretched across the intermediate transfer unit 5. The transfer belt 50 moves circulatingly so as to face and be in contact with all the photosensitive drums 1, and primary transfer is performed from the photosensitive drums 1 onto the transfer belt 50 by applying a voltage to the primary transfer rollers 58 (58a, 58b, 58c, 58d). Then, the toner on the transfer belt 50 is transferred to the recording medium S by applying a voltage to the opposing roller 59 and the secondary transfer roller 69 arranged inside the transfer belt 50.

[0017] During image formation, each photosensitive drum 1 is rotated, and the photosensitive drum 1, which has been uniformly charged by the charging roller 2, is selectively exposed to light from the scanner unit 3. This forms an electrostatic latent image on the photosensitive drum 1. The latent image is developed by the developing roller 25, thereby forming a toner image of each color on each photosensitive drum 1. In synchronization with this image formation, the registration roller pair 55 transports the recording medium S to a secondary transfer position where the opposing roller 59 and the secondary transfer roller 69 are in contact with each other with the transfer belt 50 interposed therebetween. Then, a transfer bias voltage is applied to the secondary transfer roller 69, thereby performing a secondary transfer of each color toner image on the transfer belt 50 to the recording medium S. This forms a color image on the recording medium S. The recording medium S on which the color image has been formed is heated and pressurized by the fixing unit 74 to fix the toner image. The recording medium S is then discharged to the discharge unit 75 by the discharge roller 72. The fixing unit 74 is located in the upper part of the device main body 100a.

[0018] [Process Cartridge] Next, a process cartridge 70 embodying the present invention will be described with reference to Figure 2. Figure 2 is a principal cross section of the process cartridge 70 containing toner, in the orientation in which it is installed in the image forming apparatus 100. Note that the cartridge 70Y containing yellow toner, the cartridge 70M containing magenta toner, the cartridge 70C containing cyan toner, and the cartridge 70K containing black toner all have the same configuration.

[0019] The process cartridge 70 includes a cleaning unit 26 and a developing unit 4. The cleaning unit 26 includes a photosensitive drum 1, a charging roller 2, and a cleaning member 6. The developing unit 4 includes a developing roller 25.

[0020] As described above, the charging roller 2 and cleaning member 6 are arranged on the periphery of the photosensitive drum 1. The cleaning member 6 is composed of an elastic member 7 made of a rubber blade and a cleaning support member 8. The tip of the elastic member 7 made of a rubber blade is disposed in contact with the photosensitive drum 1 in the counter direction to the rotation direction. Residual toner removed from the surface of the photosensitive drum 1 by the cleaning member 6 falls into a removed toner chamber 27.

[0021] The photosensitive drum 1 is rotated in accordance with the image forming operation by transmitting the driving force of a main body drive motor (not shown) serving as a drive source to the cleaning unit 26. At this time, a drum coupling fixed to the longitudinal end of the photosensitive drum 1 engages with a main body side coupling located on the longitudinal axis of the photosensitive drum 1, thereby inputting the driving force to the photosensitive drum 1. The charging roller 2 is rotatably attached to the cleaning unit 26 via a charging roller bearing, and is pressed against the photosensitive drum 1 by a charging roller pressure member, so that it rotates in accordance with the photosensitive drum 1.

[0022] The developing unit 4 is made up of a developing roller 25 that rotates in contact with the photosensitive drum 1, and a developing frame 31 that supports the developing roller 25. The developing frame 31 is made up of a developing chamber 31b and a toner storage chamber 31a (toner storage portion).

[0023] A toner supply roller 34 that rotates in the direction of arrow C in contact with the developing roller 25, and a developing blade 35 that regulates the toner layer on the developing roller 25 are arranged on the periphery of the developing roller 25. In this embodiment, the outer diameter of the developing roller 25 is 12 mm, and the outer diameter of the toner supply roller 34 is 13.2 mm. When the process cartridge 70 is in a position mounted in the image forming apparatus 100, the angle α between a straight line A connecting the rotation center 25e of the developing roller 25 and the rotation center 34e of the toner supply roller 34 and the horizontal line H is 9.85 degrees. However, the angle α is not limited to this.

[0024] The developing unit 4 also receives the driving force of a main body drive motor (not shown), which is separate from the driving source of the cleaning unit, to rotate the developing roller 25 and the toner supply roller 34 in accordance with the image forming operation. The driving force is input via a coupling, as with the cleaning unit 26, and details will be described later. The driving force input via a coupling is preferable from the standpoint of rotational stability compared to driving force input via gears.

[0025] The developing roller 25 is an elastic roller composed of a metal core and a conductive elastic rubber layer with a predetermined volume resistivity. The developing roller 25 consists of a base layer and a surface layer. The base layer is made of silicone rubber, and the surface layer is made of urethane rubber. Urethane beads are dispersed in the urethane rubber of the surface layer to achieve the desired roughness. The developing roller 25 and the photosensitive drum 1 rotate so that their surfaces move in the same direction (from bottom to top in this embodiment) at their opposing contact points (contact points). In this embodiment, a predetermined DC bias is applied to the developing roller 25. Negatively charged toner transfers to only the bright potential areas at the development point where the toner contacts the photosensitive drum 1, due to the potential difference, thereby visualizing the electrostatic latent image.

[0026] The developing blade 35 is positioned below the developing roller 25 and abuts against the developing roller 25, regulating the coating thickness of the toner supplied by the toner supply roller 34 and imparting a charge. In this embodiment, the developing blade 35 is composed of a flexible plate-like member and a developing blade 35 support member that secures the plate-like member. The plate-like member is made of stainless steel (SUS) and shaped like a leaf spring with a thickness of 80 μm, and the contact portion located at the free end of the plate-like member abuts the developing roller 25 with a required contact pressure. The toner supplied to the developing roller 25 is frictionally charged by friction between the developing blade 35 and the developing roller 25, imparting a charge and simultaneously regulating the layer thickness. In this embodiment, a predetermined voltage is applied to the developing blade 35 from a blade bias power supply (not shown) to stabilize the toner coating.

[0027] The charged toner adheres to the surface of the developing roller 25 due to the image force with the developing roller 25. If the adhesion force of this toner to the surface of the developing roller 25 exceeds the regulating force of the developing blade 35, the toner coat on the developing roller 25 becomes disturbed (so-called "regulation failure"). When regulation failure occurs, image defects such as toner adhering to the white background of the image or density abnormalities occur.

[0028] The developing blade 35 of this embodiment will now be described in detail. In this embodiment, the developing blade 35 is composed of a support metal plate 35a (blade support portion) made of stainless steel and a flexible plate-like member 35b (blade portion), as shown in FIG. 6. The plate-like member is integrated with the support metal plate by YAG laser welding. 3 is a conceptual cross-sectional view in the short direction of the free end tip of the developing blade 35 according to the present invention. Surface 811 in FIG. 3 is the surface that mainly comes into contact with the developing roller 25.

[0029] 3, in this embodiment, a part of the "tip edge portion 818" on the tip (free end) side of the plate-shaped member 35b that is to come into contact with the developing roller 25 is scraped off by polishing. The scraped-off portion is formed over the entire longitudinal length of the plate-shaped member.

[0030] The developing blade 35 is provided at the free end of the plate-shaped member 35 b in the widthwise direction, and has a contact portion for contacting the surface of the developing roller 25 .

[0031] More specifically, before grinding, the tip of the developing blade 35 in this embodiment has, in a cross section perpendicular to the longitudinal direction, a first surface 811 (first portion), which is the surface that contacts the developing roller 25, and a third surface 813 (third portion), which is perpendicular to the first surface 811, intersecting to form the "tip edge portion 818." Then, by grinding, the tip edge portion 818 is scraped off, and a second surface 812 (second portion) that connects the first surface 811 and the third surface 813 is formed. After grinding, the point at the tip of the first surface 811 on the free end side is designated as point A, and the point at the tip of the second surface 812 on the free end side is designated as point B. Furthermore, a virtual line extending the first surface 811 toward the free end is designated as L1. Furthermore, the point at which a virtual line L2, which is perpendicular to the virtual line L1 and passes through point B, intersects with the virtual line L1 is designated as point C. In this case, the distance between point B and point C is defined as h1, and the distance between point A and point C is defined as d1. In this embodiment, h1=15 μm, and d1=40 μm.

[0032] Next, the contact state between the developing roller 25 and the developing blade 35 will be described in detail with reference to Fig. 4. Fig. 4 is a schematic diagram showing the contact state between the developing roller 25 and the developing blade 35 in a cross section perpendicular to the longitudinal direction.

[0033] The point where a perpendicular line drawn to the surface of the developing roller 25 intersects with the surface of the developing roller relative to the tip position B of the second surface 812 in Figure 4(a) is defined as point E. Furthermore, if the contact area between the developing roller 25 and the developing blade 35 is defined as nip N1, then the contact point in nip N1 closest to the free end of the developing blade 35 is defined as point D. Point D exists on the second surface 812. The area surrounded by the surface DE of the developing roller 25, the surface BD of the developing blade, and the virtual line L2 (the shaded area in Figure 4(a)) can be defined as the "capture area J."

[0034] In this embodiment, when the developing roller 25 is assembled, the surface of the developing roller 25 does not come into contact with the tip position B of the second side, that is, at least a portion of the second side does not come into contact with the developing roller 25. This creates a state in which the entire "take-in area J" is not covered by the developing roller 25, and enables an appropriate amount of toner coat to be formed on the developing roller 25 after the developing blade 35 has passed. In other words, by ensuring the "take-in area J," the amount of toner coat can be increased, which can be said to be a weaker state of toner regulation.

[0035] Here, let L3 be the imaginary line whose distance from the surface of the developing roller 25 is the toner volume average particle diameter R, F be the intersection of L3 and the second surface 812, G be the point where the imaginary line L3 intersects with the imaginary line L2, and the tangent to the second surface 812 at point F be an imaginary line L4. Let d2 be the distance between points F and G, and θ be the angle between the imaginary line L4 and the line DE. In this example, the toner volume average particle diameter R is 7.0 μm, d2 = 20 μm, and θ2 = 20°. The toner volume average particle diameter (volume-based median diameter) was measured using a Coulter Counter Multisizer 3 (registered trademark, manufactured by Beckman Coulter, Inc.).

[0036] Here, the method of polishing the developing blade 35 used in the present invention will be described. Before joining to the support member, the plate-shaped member is fixed to the base by being sandwiched between the base and the pressing member. A polishing film wrapped around a rubber roller is in contact with the tip of the plate-shaped member under a load. In this example, a lapping film sheet with a grit size of #800 is used as the polishing film, and a load of 500 g is applied to the rubber roller.

[0037] The abrasive film on the rubber roller is arranged in a fixed state, and as the base moves left and right in the longitudinal direction, the tip of the plate-like member is rubbed against the abrasive film and finely scraped off.

[0038] The amount of scraping of the plate-shaped member is proportional to the distance it is rubbed against the abrasive film; the longer the rubbing distance, the greater the amount of scraping, and the shorter the distance, the less the amount of scraping. In other words, by controlling the amount of movement of the base, the amount of scraping of the tip edge of the plate-shaped member can be changed. The above-mentioned polishing method is one example, and is not limited to this as long as the tip shape of the developing blade can be processed into the desired shape.

[0039] The toner supply roller 34 is in contact with the developing roller 25 at a nip N2, and as shown in the figure, the toner supply roller 34 receives a driving force from a drive motor (not shown), and is rotated in response to the image forming operation. This will be explained in detail with reference to FIG.

[0040] The driving force from the main body drive motor is transmitted to coupling 201 (driving force receiving portion), and then to toner supply roller 34 via intermediate body 202 and drive transmission member 203 (intermediate body 202 and drive transmission member 203 constitute a first driving force transmission portion). The driving force of toner supply roller 34 is transmitted to developing roller 25 by gears (204a to 204c) provided between toner supply roller 34 and developing roller 25, causing the developing roller 25 to rotate (gear 204c constitutes a second driving force transmission portion, and gear 204a constitutes a third driving force transmission portion). More specifically, as gear 204c fixed to toner supply roller 34 rotates, the driving force is transmitted to idler gear 204b, which rotates. As idler gear 204b rotates, the driving force is transmitted to gear 204a fixed to developing roller 25, causing the developing roller 25 to rotate together with gear 204a.

[0041] In this embodiment, the driving force from the apparatus main body 100a to the developing unit 4 is input from the longitudinal axis of the toner supply roller 34, but if the driving force from the apparatus main body 100a to the developing unit 4 were input from the longitudinal axis of the developing roller 25, the driving force input positions to the cleaning unit 26 and the developing unit 4 would be close to each other because development is performed by contacting the photosensitive drum 1 and the developing roller 25. With such an input portion arrangement, it is difficult to simply configure the driving force input portion of the apparatus main body 10, and this is not preferable when configuring a more stable driving force input portion at low cost.

[0042] In contrast to this, in this embodiment, the driving force to the developing unit 4 is input from the longitudinal axis of the toner supply roller 34, so the distance between the input position to the cleaning unit 26 and the driving force input position to the developing unit 4 can be increased, which is more preferable when configuring the driving force input section of the device main body 100a.

[0043] On the other hand, in the configuration of this embodiment, the driving force from the apparatus main body 100a is transmitted to the developing roller 25 via the toner supply roller 34, and therefore multiple gears must be used to drive the developing roller 25, which results in less rotational stability of the developing roller 25 than in a configuration in which the driving force is transmitted to the developing roller 25. As a result, the regulating force of the developing blade 35 may become unstable, making this a disadvantageous configuration in terms of regulating failure.

[0044] In addition, the toner supply roller 34 and the developing roller 25 rotate in opposite directions at different peripheral speeds at the nip portion N2, and this operation recovers the remaining toner on the developing roller 25 while supplying toner to the developing roller 25.

[0045] In this embodiment, when the peripheral speed of the toner supply roller 34 at the nip portion N2 is Vrs and the peripheral speed of the developing roller 25 is Vd, the ratio Vrs / Vd is set to 1.25 so that Vrs / Vd > 1. That is, when the radius of the toner supply roller 34 is Rrs [mm], the rotational angular velocity of the toner supply roller 34 is ωrs [rad / sec], the radius of the developing roller 25 is Rd [mm], the rotational angular velocity of the developing roller 25 is ωd [rad / sec], and the rotational angular velocity ratio λ (=ωrs / ωd) between the toner supply roller 34 and the developing roller 25 is λ × Rrs / Rd > 1.0. In this embodiment, the radius of the toner supply roller is 3.3 mm and the radius of the developing roller is 3.0 mm, so λ ≈ 1.14. By making Vrs / Vd>1, it is possible to efficiently collect the remaining toner on the developing roller 25 and supply toner to the developing roller 25. On the other hand, from the viewpoint of poor regulation, this is a disadvantageous configuration because the amount of toner supplied increases.

[0046] At this time, by adjusting the potential difference between the toner supply roller 34 and the developing roller 25, the amount of remaining toner collected on the developing roller 25 and the amount of toner supplied to the developing roller 25 can be adjusted.

[0047] The toner supply roller 34 and the developing roller 25 are in contact with each other with a predetermined intrusion amount, that is, the amount of depression ΔE that the toner supply roller 34 is made into a depression by the developing roller 25 .

[0048] The toner supply roller 34 comprises a conductive support and a foam layer supported by the conductive support. Specifically, the conductive support is a core metal electrode having an outer diameter of 5 mm, and a foamed urethane layer is provided around the core metal electrode as a foamed layer composed of open-cell foam (open cells) in which the cells are connected to each other. The toner supply roller 34 rotates in the direction of C in the figure. By making the urethane surface layer open-cell foam, a large amount of toner can penetrate into the toner supply roller 34. In this embodiment, the resistance of the toner supply roller 34 is 1×10^9 (Ω).

[0049] In this embodiment, the amount of penetration of the toner supply roller 34 into the developing roller 25, i.e., the amount of depression ΔE of the toner supply roller 34 caused by the developing roller 25, was set to 1.0 mm. Here, a method for measuring the resistance of the toner supply roller 34 will be described. The toner supply roller 34 was brought into contact with an aluminum sleeve having a diameter of 30 mm so that the amount of penetration, described below, was 1.5 mm. By rotating this aluminum sleeve, the toner supply roller 34 was rotated at 30 rpm relative to the aluminum sleeve.

[0050] Next, a DC voltage of −50 V is applied to the developing roller 25. At this time, a 10 kΩ resistor is provided on the ground side, and the current is calculated by measuring the voltage across the resistor, and the resistance of the toner supply roller 34 is calculated. In this embodiment, the surface cell diameter of the toner supply roller 34 is set to 50 μm to 1000 μm.

[0051] Here, the cell diameter refers to the average diameter of foam cells in an arbitrary cross section. First, the area of ​​the largest foam cell is measured from an enlarged image of the arbitrary cross section, and the maximum cell diameter is obtained by converting this area into a diameter equivalent to a perfect circle. Then, foam cells having a diameter equal to or smaller than half of this maximum cell diameter are eliminated as noise, and the remaining individual cell areas are similarly converted to obtain the average cell diameter.

[0052] The toner supplied from the toner supply roller 34 to the surface of the developing roller 25 is frictionally charged by the friction between the developing blade 35 and the developing roller 25, and the layer thickness is regulated while the toner is given an electric charge. The toner is then transported to the contact portion (developing portion) between the photosensitive drum 1 and the developing roller 25, and transferred to the light potential portion. Residual toner remaining on the surface of the developing roller 25 returns to the developer container, is collected from the surface of the developing roller 25 by the toner supply roller 34, and is stored inside the toner supply roller 34.

[0053] The flow of toner inside the developing chamber 31b will now be described with reference to Fig. 6. In this embodiment, Fig. 6 is an enlarged schematic cross-sectional view of the inside of the developing chamber 31b, showing the movement of toner transported from the toner transport member 36 shown in Fig. 2 to the toner supply roller 34.

[0054] A portion of the toner G transported to the top of the toner supply roller 34 by the toner transport member 36 is sucked into the toner supply roller 34 due to the restoration of the toner supply roller 34 downstream of the rotation of the nip portion N2 (F1), and is stored inside the toner supply roller 34 together with the remaining toner collected from the surface of the developing roller 25 and stored inside the toner supply roller 34. Then, as the toner supply roller 34 rotates in the direction C, the toner G is transported downstream of the rotation of the toner supply roller 34 at the nip portion N2. At the downstream side of the rotation of the toner supply roller 34, the toner supply roller 34 comes into contact with the developing roller 25, causing deformation of the toner supply roller 34, which causes the toner stored inside to be expelled (F2).

[0055] The toner discharged from the toner supply roller 34 that does not reach the surface of the developing roller 25 is gradually transported by the propulsion force toward the developing opening (opening) due to the ejection force from the toner supply roller 34, and is returned through the developing opening to the toner storage chamber 31a (F3).

[0056] In this way, the toner circulates smoothly between the developing chamber 31b and the toner storage chamber 31a, which suppresses toner deterioration and prevents toner aggregation even when images with low print coverage are output continuously, allowing high-quality images to be output stably.

[0057] If the flow (F3) of toner returning to the toner storage chamber 31a becomes insufficient, the toner will be compressed and aggregated in the area below the toner supply roller 34 and the developing roller 25. This will cause toner to enter the nip N2 between the toner supply roller 34 and the developing roller 25, resulting in insufficient contact between the toner supply roller 34 and the developing roller 25. This will result in an area where the toner supply roller 34 is unable to sufficiently collect the remaining toner on the developing roller 25, causing certain toner to be carried around by the developing roller 25 and pass through the contact area between the developing blade 35 and the developing roller 25 more than necessary, resulting in excessively charged toner. As a result, the toner's adhesive force will exceed the restricting force of the developing blade 35, which can cause a restriction failure.

[0058] This phenomenon is likely to occur, for example, when images with a low printing rate are continuously output in a low-temperature, low-humidity environment. This is because the residual toner collected from the developing roller 25 by the toner supply roller 34 accumulates in the developing chamber 31b. Because the residual toner collected from the developing roller 25 is charged, the toner particles tend to electrostatically clump together. This reduces the fluidity of the toner in the developing chamber 31b, making the flow of toner (F3) returning to the toner storage chamber 31a insufficient, and creating a state in which toner clumping is likely to occur in the areas below the toner supply roller 34 and the developing roller 25.

[0059] One solution to this problem is to place a toner transport member below the toner supply roller 34 in the developing chamber 31b, thereby creating a toner flow (F3) that returns to the toner storage chamber 31a. However, if a toner transport member is provided in the developing chamber 31b, friction between the toner and the toner transport member in the developing chamber 31b accelerates toner deterioration, and toner fusion to the developing roller 25 has been observed when low-coverage images are continuously produced. Furthermore, since a toner transport member must be provided as an additional component in addition to the toner supply roller 34 in the developing chamber 31b, the device configuration becomes complicated. Therefore, in this embodiment, no components driven by a motor are provided in the developing chamber 31b other than the developing roller 25 and the toner supply roller 34.

[0060] In addition, in a configuration in which only the developing roller 25 and the toner supply roller 34 are disposed in the developing chamber 31b, in order to efficiently use the toner in the developing chamber 31b, the inner wall of the developing chamber 31b is set as follows relative to the toner supply roller 34. This will be specifically explained with reference to FIG.

[0061] 7, R1 and R2 indicate tangents (vertical lines) to the outer peripheral surface of the toner supply roller 34 that extend in the vertical direction. Furthermore, horizontal line H2 indicates a horizontal line that passes through the support end of the developing blade 35. In the region of the inner wall of the developing chamber 31b between R1 and R2, at least a portion is positioned vertically above the horizontal line H2 (region 138 in the figure). This allows for a further reduction in the amount of toner remaining in the developing chamber 31b that is not used for printing, thereby enabling more efficient use of the toner in the developing chamber 31b.

[0062] As shown in FIG. 2, a blowout prevention sheet 20 is disposed as a developer contact sheet for preventing toner from leaking from the developing frame 31 in contact with the developing roller 25 .

[0063] Furthermore, the toner storage chamber 31a of the developing frame 31 is provided with a toner transport member 36 for stirring the stored toner and transporting the toner to the toner supply roller 34. As shown in Fig. 2, the toner transport member 36 is composed of a stirring shaft 36a that can be rotated by a driving force from the apparatus main body 100a, and a sheet member 36b that is attached to the stirring shaft 36a and rotates together with the stirring shaft 36a.

[0064] Next, toner transport in the development unit will be described. The toner storage chamber 31a has a deforming portion 31a1 below the opening 31c (communication port) that contacts the sheet member 36b. As the sheet member 36b rotates, it contacts the deforming portion 31a1. This causes the sheet member 36b to receive force from the deforming portion 31a1. As a result, the sheet member 36b deforms against its own elastic force. Furthermore, as the sheet member 36b rotates while in contact with the deforming portion 31a1, toner is transported while being carried on the surface downstream of the rotation. In this embodiment, the deforming portion 31a1 refers to the portion of the inner wall of the toner storage chamber that extends up to the point where the sheet member 36b separates, as shown in FIG. 2 .

[0065] The toner storage chamber 31a is provided with a restoring portion 31a2 downstream of the deforming portion 31a1 and upstream of the opening 31c in the rotation of the sheet member 36b. The restoring portion 31a2 serves to release the contact between the sheet member 36b and the inner wall of the toner storage chamber 31a. In this embodiment, the restoring portion 31a2 is located above a horizontal plane including the rotation axis of the agitator.

[0066] Therefore, as the sheet member 36b rotates, the leading edge of the free end of the sheet member 36b passes through the deformation portion 31a1, and then the sheet member 36b is released from contact with the inner wall at the restoration portion 31a2. The sheet member 36b is then released from its deformed state by the deformation portion 31a1 and returns to its natural state (original shape) due to its own elastic restoring force. This deformation of the sheet member 36b in the restoration direction causes the toner carried and transported on the sheet member 36b to fly against gravity toward the opening 31c. This opening 31c is located downstream of the restoration portion 31a2 in the direction of rotation of the sheet member 36b. Some of the toner that flies toward the opening 31c is transported into the developing chamber 31b. Meanwhile, the toner that does not reach the developing chamber 31b falls into the toner storage chamber 31a, where it remains at the bottom and returns to its original state. This cycle is repeated to agitate and transport the toner.

[0067] The configuration having the deformation portion 31a1 and the restoration portion 31a2 is advantageous for increasing the efficiency of transporting toner to the developing chamber 31b, but it is a configuration that is likely to obstruct the flow of toner returning to the toner storage chamber (F3), and therefore is prone to causing regulation problems.

[0068] In this embodiment, the length of the sheet member 36b in the direction of the rotation radius of the rotation axis in the natural state is set to be longer than the distance from the rotation axis to the lower end of the developing opening in the same direction. This configuration is advantageous for improving the efficiency of toner transport to the developing chamber 31b, but it is likely to obstruct the flow of toner (F3) returning to the toner storage chamber 31a, making it prone to regulation failure.

[0069] In this embodiment, two sets of sheet members 36b are attached at offset positions on the agitator shaft 36a to ensure that a sufficient amount of toner can be transported from the toner storage chamber 31a to the developing chamber 31b. This configuration is advantageous for increasing the efficiency of toner transport to the developing chamber 31b, but it is prone to obstructing the flow of toner (F3) returning to the toner storage chamber 31a, making it prone to regulation failure.

[0070] [Toner] Next, the toner of the present invention will be described. Hereinafter, unless otherwise specified, the expressions "XX or more and YY or less" and "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. "(Meth)acrylic" means "acrylic" and / or "methacrylic".

[0071] The toner used in this example is a toner containing toner particles containing a binder resin, including hydrotalcite particles used as microcarriers to enhance the negative charging characteristics of the toner particles. Additionally, the hydrotalcite particles contain fluorine. Hydrotalcite particles have a high positive charging tendency, resulting in a strong positive charge. By incorporating fluorine into the hydrotalcite particles, the charge amount can be adjusted so that they do not have a strong positive charge. By incorporating fluorine, the hydrotalcite particles can be prevented from being strongly positively charged, thereby preventing the toner from becoming strongly negative. In other words, the charge distribution of the toner can be made to have a sharp negative charge distribution. As an example, a toner containing fluorine-free hydrotalcite and a toner containing fluorine-containing hydrotalcite were prepared using the same toner particles (described below) and the same toner particles (Toner 1), and the charge distribution of the toner was measured. Using the image forming apparatus 100 and process cartridge 70 of this example, toner on the developing roller 25 was sampled after forming one plain (solid white) image. The charge amount of the sampled toner was measured. The charge amount was measured using an E-SpartAnalyzer manufactured by Hosokawa Micron Corporation. The percentage of strongly negative toner particles with a charge amount per unit weight Q / M of -25 μC / g or more (evaluated as an absolute value) was compared. It was confirmed that the percentage of strongly negative toner particles was reduced by approximately 23% for the toner with fluorine-containing hydrotalcite added, compared to the toner with non-fluorine-containing hydrotalcite added.

[0072] By using toner with fluorine-containing hydrotalcite added to the outside and the developing blade 35 having the aforementioned "capture area J" at the leading edge, it is possible to suppress the regulation failure. The mechanism behind this is explained below.

[0073] 4A, the developing blade 35 has an "intake area J" at its leading edge, and the toner particles rub against each other in the "intake area J," thereby transferring the charge that the toner particles have. This makes it possible to achieve a sharp charge distribution for the toner passing through the restricting portion of the developing blade 35.

[0074] On the other hand, when using a developing blade 35 that does not have an "intake area J" as shown in Figure 4 (b), in order to obtain the toner coat amount necessary to obtain the desired image density, it is necessary to set the contact position of the developing roller 25 with the developing blade 35 on the fixed end side.

[0075] Figure 8 explains the movement of toner regulated by the developing blade 35 when a developing blade 35 with an "uptake area J" at the leading edge is used, and when a developing blade 35 without an "uptake area J" at the leading edge is used.

[0076] FIG. 8A illustrates the use of a developing blade 35 with a "capture area J" at its leading edge. The white circles in the figure represent toner particles, and the arrow K1 indicates the movement of the toner restricted by the developing blade 35. As the developing roller 25 rotates in the direction of arrow D1, some of the toner particles penetrate close to the contact point D with the developing blade 35, and are then detached from the surface of the developing roller 25 by the restricting force of the developing blade 35. This restricted toner particles move in a direction where the toner powder pressure from behind is weaker, and thus move back into the developing chamber 31b along the second surface 812 of the leading edge. As a result, good toner circulation is achieved in the "capture area J" at the leading edge, and during this circulation, the toner particles can transfer their electric charge through friction with each other.

[0077] It is believed that the "take-in area J" at the leading edge of the developing blade 35 has a point F on the developing blade 35 that is at least a distance from the developing roller 25 that is greater than the toner volume average particle size R, and that the width d2 of the take-in area on the free end side of point F is greater than the toner volume average particle size R, i.e., one toner particle can exist in the "take-in area," causing the above-mentioned toner circulation to occur. The toner used in this embodiment has a volume average particle size of about 7.0 μm, and the leading edge shape of the developing blade is polished so that point F exists and d2 is greater than the toner volume average particle size R.

[0078] Furthermore, if the angle θ between the developing blade 35 and the developing roller 25 at point F is preferably set to 45° or less, the direction of the arrow K1 will be more opposite to the direction of movement of the developing roller 25, which will result in more frequent rubbing of toner particles against each other in the "take-in area J," making it easier to achieve the effect of transferring the charge held by the toner. More preferably, setting θ to 25° or less will make it easier to achieve the above effect.

[0079] On the other hand, Figure 8(b) shows a case where a developing blade 35 without a "capture area J" at the leading edge is used. When using such a developing blade 35, in order to obtain the desired toner coating amount to obtain the desired image density, the contact point D of the developing roller 25 with the developing blade 35 must be set closer to the fixed end than the developing blade 35 in Figure 8(a). This setting allows a sufficient amount of toner to be captured into the regulating portion. At this time, the toner regulated by the regulating force of the developing blade 35 is unlikely to return to the developing chamber 31b due to the powder pressure of the toner transported from behind by the rotation of the developing roller 25. As a result, the regulated toner generates a force in the direction K2 that pushes up the developing blade 35. This reduces the contact pressure of the developing blade 35 against the developing roller 25, weakening the regulating force of the developing blade 35. As a result, the toner's adhesion force to the developing roller 25 exceeds the regulating force of the developing blade 35, which may result in a regulating failure.

[0080] Furthermore, when toner with externally added fluorine-free hydrotalcite is used, the amount of toner with a strong negative polarity increases compared to toner with externally added fluorine-containing hydrotalcite, as described above. As a result, when a developing blade 35 without an "intake region J" at its leading edge is used, the regulating force of the developing blade 35 weakens, and regulating failures are likely to occur, just as with toner with externally added fluorine-containing hydrotalcite.

[0081] Furthermore, even if a developing blade 35 having a "capture area J" at its leading edge is used and toner particles are rubbed against each other in the "capture area J," the proportion of toner particles with a strong negative polarity increases. As a result, toner particles may adhere to the developing roller 25 with a force that exceeds the restricting force of the developing blade 35, which may result in a restriction failure.

[0082] Furthermore, as the proportion of strongly negative toner particles increases, electrostatic aggregation of toner particles is likely to occur, which may result in poor toner flow (F3) into the toner storage chamber 31a and insufficient flow, potentially resulting in poor regulation.

[0083] To summarize the above, by using toner with fluorine-containing hydrotalcite added to its exterior and a developing blade 35 with an "intake area J" at its leading edge, the "intake area J" promotes friction between toner particles, thereby preventing the toner from being strongly negatively charged. As a result, the generation of toner particles with an adhesion force to the developing roller 25 that exceeds the restricting force of the developing blade 35 can be prevented. At the same time, electrostatic aggregation of toner particles can be prevented, and by maintaining a sufficient flow (F3) of toner into the toner storage chamber 31a, the generation of toner aggregation in the areas below the toner supply roller 34 and the developing roller 25 can be prevented.

[0084] Due to these two effects, the occurrence of regulation failure can be suppressed by using toner to which fluorine-containing hydrotalcite is externally added and a development blade 35 provided with an "intake area J" at the leading edge portion.

[0085] In this embodiment, in order to more actively transfer the charge of the toner particles due to friction between the toner particles in the "capture area J," the capture angle θ is set to be between 0°<θ<25°. This makes it possible to achieve a sharp charge distribution of the toner passing through the regulating portion of the developing blade 35.

[0086] The hydrotalcite particles used in the toner of this embodiment will be described in detail. The hydrotalcite particles contain fluorine. Here, the presence or absence of fluorine in the hydrotalcite particles can be confirmed by STEM-EDS mapping analysis of the toner. The analysis conditions and the like are described below. Furthermore, in the line analysis of the STEM-EDS mapping analysis of the toner, fluorine is present inside the hydrotalcite particles. Specifically, this means that EDS line analysis is performed in the normal direction to the outer periphery of the fluorine-containing hydrotalcite particles, and fluorine present inside the particles is detected. The detection of fluorine inside the hydrotalcite particles by the above analysis indicates that fluorine is intercalated between the layers of the hydrotalcite particles. The presence of fluorine inside the hydrotalcite particles prevents the hydrotalcite particles from being excessively positively charged, allowing them to maintain an appropriate amount of positive charge. The reason why the hydrotalcite particles can maintain an appropriate amount of positive charge is that the presence of fluorine, which has a strong negative polarity, inside the hydrotalcite particles allows the positive charge on the surface of the hydrotalcite particles to be absorbed into the particles and neutralized, i.e., it is believed that this is because excessive positive charging of the particle surface can be suppressed.

[0087] It is preferable that fluorine is introduced into the interior of the hydrotalcite particles by introducing fluoride ions between the layers (intercalation) through anion exchange.

[0088] The ratio of the atomic concentration of fluorine to aluminum in the hydrotalcite particles, F / Al (element ratio), obtained from the main component mapping of the hydrotalcite particles by STEM-EDS mapping analysis of the toner, is preferably 0.01 to 0.65. It is more preferably 0.02 to 0.60. Specifically, when F / Al is 0.01 or more, the surface charge distribution of the hydrotalcite particles can be made uniform, improving the charge stability of the toner. As a result, a toner that is sharply charged to a negative polarity can be obtained. Furthermore, when F / Al is 0.65 or less, excessive neutralization of the surface charge of the hydrotalcite particles is suppressed, the time stability of the positive charge is improved, and the charge stability of the toner is improved. As a result, the charge of the toner is prevented from becoming strongly negative, and a toner with a sharp negative charge distribution can be obtained.

[0089] The fluorine atom concentration in the hydrotalcite particles is not particularly limited, but is preferably 0.01 atomic % to 5.00 atomic %, more preferably 0.04 atomic % to 3.00 atomic %, and even more preferably 0.09 atomic % to 2.00 atomic %. Within this range, the hydrotalcite particles have an appropriate positivity and the microcarrier properties are in an appropriate range.

[0090] The hydrotalcite particles may be those represented by the following composition formula (1): In the composition formula (1), M and A are expressed in an ionic state. ２＋ ｙ M ３＋ ｘ (OH) ２ A ｎ－ （ｘ／ｎ） ・mH ２ O Formula (1) ２＋ , and M ３＋ represent divalent and trivalent metal cations, respectively.

[0091] The hydrotalcite particles may be a solid solution containing a plurality of different elements. Also, they may contain a small amount of monovalent metal. However, it is preferable that 0<x≦0.5, y=1−x, and m≧0. M ２＋ is preferably a divalent cation of at least one metal selected from the group consisting of Mg, Zn, Ca, Ba, Ni, Sr, Cu, and Fe. ３＋ is preferably a trivalent cation of at least one metal selected from the group consisting of Al, B, Ga, Fe, Co, and In. ｎ－ is an n-valent anion, and contains at least F － Includes. A ｎ－ Is F － Besides, CO ３ ２－ , O.H. － , Cl － , I － ,Br － , S.O. ４ ２－ , HCO ３ － , C.H. ３ COO － , and NO ３ － and the like, and may contain a plurality of different anions.

[0092] The metal that becomes the divalent cation is preferably Mg (magnesium), and the metal that becomes the trivalent cation is preferably Al (aluminum). The hydrotalcite particles preferably contain aluminum that becomes the trivalent cation and magnesium that becomes the divalent cation. A specific composition formula is Mg ２＋ ８．６ Al ３＋ ４ (OH) ２５．２ F － ２ CO ３ ２－ ・mH ２ O, Mg ２＋ １２ Al ３＋ ４ (OH) ３２ F －２ CO ３ ２－ ・mH ２ Examples include O.

[0093] When the hydrotalcite particles contain aluminum that becomes a trivalent cation and magnesium that becomes a divalent cation, the ratio (Mg / Al) of the atomic concentration (atomic %) of magnesium to the atomic concentration (atomic %) of aluminum is preferably 1.50 to 4.00.

[0094] Furthermore, the hydrotalcite particles preferably have water in their molecules, and more preferably, in formula (1), 0.1<m<0.6.

[0095] The number average particle diameter H3 of the primary particles of the hydrotalcite particles is preferably 40 nm to 1100 nm, and more preferably 60 nm to 1000 nm. When the number average particle diameter of the hydrotalcite particles is in the above range, the charge rise property of the toner is good, and the charge distribution of the toner is easily made sharp.

[0096] The particle size can be measured using a known means such as a scanning electron microscope, etc. The particle size can also be controlled by controlling the conditions of the reaction step, pulverization step, centrifugation step, classification step, and sieving step in the production process of the hydrotalcite particles.

[0097] The hydrotalcite particles may be hydrophobized with a surface treatment agent. Examples of the surface treatment agent include higher fatty acids, coupling agents, esters, and oils such as silicone oil. Among these, higher fatty acids are preferably used, and specific examples include stearic acid, oleic acid, and lauric acid.

[0098] The content of hydrotalcite particles in the toner is not particularly limited. It is preferably 0.01 to 3.00 parts by mass, more preferably 0.05 to 0.50 parts by mass, and even more preferably 0.05 to 0.30 parts by mass, relative to 100 parts by mass of toner particles. The content of hydrotalcite particles can be quantified using fluorescent X-ray analysis and a calibration curve prepared from a standard sample.

[0099] The adhesion rate of the hydrotalcite particles to the toner particles is preferably 10% to 95%, more preferably 40% to 95%, and even more preferably 50% to 70%. Within this range, the above effects are easily obtained. The adhesion rate can be controlled by changing the external addition conditions using a known external addition method.

[0100] The area ratio of the hydrotalcite particles to the toner particles in the EDS measurement field of view, as measured by STEM-EDS mapping analysis of the toner, is preferably 0.07% to 0.54%. It is more preferably 0.25% to 0.50%, and even more preferably 0.35% to 0.45%. Within this range, the above effects are easily achieved. The area ratio can be controlled by changing the amount of the hydrotalcite particles added.

[0101] <Method for producing toner particles> The method for producing toner particles is not particularly limited and known means can be used, and a kneading and pulverization method or a wet production method can be used. A wet production method is preferred from the viewpoints of uniform particle size, shape controllability, and ease of obtaining toner particles with a core-shell structure. Examples of wet production methods include a suspension polymerization method, a solution suspension method, an emulsion polymerization aggregation method, and an emulsion aggregation method (the difference between emulsion polymerization aggregation and emulsion aggregation). An emulsion aggregation method is more preferred from the viewpoint of dispersing the polyvalent metal element on the surface of the toner particles and inside the toner particles.

[0102] In the emulsion aggregation method, first, a dispersion of each material, such as binder resin particles and colorant, is prepared. The resulting dispersion of each material is dispersed and mixed, with the addition of a dispersion stabilizer as needed. Then, an aggregating agent is added to aggregate the particles to the desired toner particle size, and then, or simultaneously with the aggregation, the resin particles are fused together. If necessary, the shape is controlled by heat to form toner particles.

[0103] Here, the binder resin microparticles can also be composite particles formed of two or more layers made of resins with different compositions. For example, they can be produced by emulsion polymerization, mini-emulsion polymerization, phase inversion emulsification, or a combination of several production methods. When an internal additive is contained in the toner particles, the internal additive may be contained in the resin microparticles, or a dispersion of internal additive microparticles consisting only of the internal additive may be separately prepared, and the internal additive microparticles may be aggregated together with the resin microparticles when they are aggregated. Furthermore, toner particles with layer structures of different compositions can be produced by adding resin microparticles with different compositions at different times during aggregation and causing them to aggregate.

[0104] Known surfactants can be used as the dispersion stabilizer. Suitable flocculants include surfactants with polarity opposite to that of the surfactants used in the dispersion stabilizer, inorganic salts, and divalent or higher inorganic metal salts. In particular, inorganic metal salts are preferred because they ionize polyvalent metal elements in an aqueous medium, making it easy to control the flocculation and toner chargeability. Specific examples of preferred inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, iron chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyiron chloride, polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Among these, aluminum salts and their polymers are particularly preferred. In general, to obtain a sharper particle size distribution, the valence of the inorganic metal salt is preferably divalent rather than monovalent, and trivalent or higher rather than divalent. Furthermore, even if the valence is the same, inorganic metal salt polymers are more suitable.

[0105] From the viewpoint of high definition and high resolution of images, the volume-based median diameter of the toner particles is preferably 3.0 μm to 10.0 μm.

[0106] <Toner Manufacturing Method> The toner contains hydrotalcite particles as an external additive. If necessary, other external additives may be added. In this case, the total content of external additives such as inorganic and organic fine particles including hydrotalcite particles is preferably 0.50 parts by mass to 5.00 parts by mass per 100 parts by mass of toner particles.

[0107] The mixer for externally adding the external additive to the toner particles is not particularly limited, and any known mixer, whether dry or wet, can be used. Examples include an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.), a Mitsui Henschel mixer (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), a Supermixer (manufactured by Kawata Corporation), a Nobilta (manufactured by Hosokawa Micron Corporation), and a Hybridizer (manufactured by Nara Kikai Co., Ltd.). In order to control the coating state of the external additive, the toner can be prepared by adjusting the rotation speed, processing time, and water temperature and amount in the jacket of the external addition device.

[0108] The methods for measuring the physical properties of the toner and each material are described below. <Method for Identifying Hydrotalcite Particles> Hydrotalcite particles can be identified by a combination of shape observation using a scanning electron microscope (SEM) and elemental analysis using energy dispersive X-ray analysis (EDS).

[0109] Using a scanning electron microscope "S-4800" (trade name; manufactured by Hitachi, Ltd.), the toner is observed in a field of view magnified up to 50,000 times. The focus is adjusted to the surface of the toner particles, and the external additive to be identified is observed. EDS analysis of the external additive to be identified is performed, and the hydrotalcite particles can be identified from the type of element peak.

[0110] When element peaks observed include an element peak of at least one metal selected from the group consisting of Mg, Zn, Ca, Ba, Ni, Sr, Cu, and Fe, which are metals that can constitute hydrotalcite particles, and an element peak of at least one metal selected from the group consisting of Al, B, Ga, Fe, Co, and In, the presence of hydrotalcite particles containing the two types of metals can be inferred.

[0111] A sample of the hydrotalcite particles identified by the EDS analysis is separately prepared, and its shape is observed by SEM and analyzed by EDS. The analysis results of the sample are compared to the analysis results of the particles to be identified to determine whether they are hydrotalcite particles.

[0112] <Method for measuring the ratio of each element in hydrotalcite particles> The ratio of each element in hydrotalcite particles is measured by EDS mapping measurement of the toner using a scanning transmission electron microscope (STEM). In EDS mapping measurement, spectral data is obtained for each pixel in the analysis area. By using a silicon drift detector with a large detection element area, EDS mapping can be measured with high sensitivity.

[0113] By performing statistical analysis on the spectral data of each pixel obtained by EDS mapping measurement, it is possible to obtain a principal component mapping that extracts pixels with similar spectra, making it possible to map components that are specific to them.

[0114] The sample for observation was prepared as follows: 0.5 g of toner was weighed out and placed in a cylindrical mold with a diameter of 8 mm using a Newton press, which was left to stand for 2 minutes under a load of 40 kN to prepare a cylindrical toner pellet with a diameter of 8 mm and a thickness of approximately 1 mm. A 200 nm-thick slice was prepared from the toner pellet using an ultramicrotome (Leica, FC7).

[0115] The STEM-EDS analysis was performed using the following equipment and conditions: Scanning transmission electron microscope: JEOL Ltd. JEM-2800 EDS detector: JEOL Ltd. JED-2300T Dry SD100GV detector (detector element area: 100 mm ２) EDS analyzer: NORAN System 7 manufactured by Thermo Fisher Scientific [STEM-EDS conditions] STEM acceleration voltage: 200 kV Magnification: 20,000 times Probe size: 1 nm STEM image size: 1024 x 1024 pixels (EDS element mapping images are obtained at the same position.) EDS mapping size: 256 x 256 pixels, Dwell time: 30 μs, number of accumulations: 100 frames

[0116] The ratio of each element in the hydrotalcite particles is calculated based on multivariate analysis as follows.

[0117] The EDS mapping is obtained using the STEM-EDS analysis device. Next, the collected spectral mapping data is subjected to multivariate analysis using the COMPASS (PCA) mode in the measurement command of the NORAN System 7, and a principal component map image is extracted.

[0118] The settings were as follows: Kernel size: 3 x 3 Quantitative map setting: High (slow) Filter fit type: High accuracy (slow)

[0119] At the same time, this operation calculates the area ratio of each extracted principal component to the EDS measurement field of view. Quantitative analysis is performed on the EDS spectrum of each principal component mapping obtained using the Cliff-Lorimer method.

[0120] The toner particle portion and the hydrotalcite particles are distinguished based on the quantitative analysis results of the obtained STEM-EDS main component mapping. The particles can be identified as hydrotalcite particles based on the particle size, shape, content of polyvalent metals such as aluminum and magnesium, and their quantitative ratio.

[0121] <Method for Analyzing Fluorine and Aluminum in Hydrotalcite Particles> Based on the mapping data obtained by the STEM-EDS mapping analysis using the method described above, the fluorine and aluminum in the hydrotalcite particles are analyzed. Specifically, EDS line analysis is performed in the normal direction to the outer periphery of the hydrotalcite particles, and the fluorine and aluminum present inside the particles are analyzed.

[0122] 9A shows a schematic diagram of the line analysis. For a toner particle 91 and a hydrotalcite particle 93 adjacent to a toner particle 92, line analysis is performed in the normal direction to the outer periphery of the hydrotalcite particle 93, i.e., in the direction 95. Note that 94 indicates the boundary of the toner particle.

[0123] The area in the acquired STEM image where the hydrotalcite particles are present is selected using a rectangular selection tool, and line analysis is performed under the following conditions: Line analysis conditions: STEM magnification: 800,000x; Line length: 200 nm; Line width: 30 nm; Number of line divisions: 100 points (intensity measurement every 2 nm)

[0124] The criteria for determining that the element is contained inside the hydrotalcite particles are as follows: When the element peak intensity of fluorine or aluminum is 1.5 times or more the background intensity in the EDS spectrum of the hydrotalcite particles. When the element peak intensity of fluorine or aluminum at both ends of the hydrotalcite particles (points a and b in Figure 9(a)) in line analysis does not exceed 3.0 times the peak intensity at point c. When all of the above conditions are met, the element is determined to be contained inside the hydrotalcite particles. Note that point c is the midpoint of line segment ab (i.e., the midpoint of the above-mentioned both ends).

[0125] Examples of X-ray intensities of fluorine and aluminum obtained by line analysis are shown in Figures 9(b) and 9(c). When the hydrotalcite particles contain fluorine and aluminum inside, the graph of X-ray intensity normalized by peak intensity shows a shape like that shown in Figure 9(b). When the hydrotalcite particles contain fluorine derived from the surface treatment agent, the graph of X-ray intensity normalized by peak intensity has peaks near points a and b at both ends of the fluorine graph, as shown in Figure 9(c). By checking the X-ray intensities derived from fluorine and aluminum in line analysis, it can be confirmed that the hydrotalcite particles contain fluorine and aluminum inside.

[0126] <Method for calculating the atomic concentration ratio (element ratio) F / Al of fluorine to aluminum in hydrotalcite particles> The atomic concentration ratio (element ratio) F / Al of fluorine to aluminum in the hydrotalcite particles is obtained from the main component mapping derived from the hydrotalcite particles by the STEM-EDS mapping analysis described above, and is obtained from multiple fields of view. The arithmetic average of 100 or more relevant particles is then taken to determine the atomic concentration ratio (element ratio) F / Al of fluorine to aluminum in the hydrotalcite particles.

[0127] <Method of calculating the atomic concentration ratio (element ratio) Mg / Al of magnesium to aluminum in the hydrotalcite particles> The same method as the method for calculating the atomic concentration ratio (element ratio) F / Al of fluorine to aluminum in the hydrotalcite particles described above is used to calculate the atomic concentration ratio (element ratio) Mg / Al of magnesium to aluminum in the hydrotalcite particles.

[0128] <Method for calculating the atomic concentration of fluorine in hydrotalcite particles> The atomic concentration of fluorine in the hydrotalcite particles is calculated based on the mapping data obtained by the STEM-EDS mapping analysis using the method described above. The atomic concentration of fluorine (element amount) in the hydrotalcite particles is quantified using the map image of the main components of the hydrotalcite particles extracted using the method described above.

[0129] The mapping data is obtained from a plurality of fields of view, and the arithmetic mean of the data for 100 or more hydrotalcite particles is taken as the fluorine atom number concentration in the hydrotalcite particles.

[0130] <Method for Measuring Number Average Particle Size of Primary Particles of Hydrotalcite Particles> The number average particle size S3 of primary particles of hydrotalcite particles is measured using a scanning electron microscope "S-4800" (trade name; manufactured by Hitachi, Ltd.) in combination with elemental analysis by energy dispersive X-ray analysis (EDS). A toner to which hydrotalcite particles have been externally added as an external additive is observed, and the hydrotalcite particles are photographed in a field of view magnified up to 200,000 times. Hydrotalcite particles are selected from the photographed image, and the major axis of the primary particles of 100 hydrotalcite particles selected at random is measured to determine the number average particle size of the hydrotalcite particles. The observation magnification is adjusted appropriately depending on the size of the external additive.

[0131] <Method for Measuring the Adhesion Ratio of Hydrotalcite Particles to Toner Particles> First, two types of samples (toner before washing and toner after washing) were prepared. (i) Toner before washing: Various toners prepared in the examples described below were used as they were. (ii) Toner after washing: 160 g of sucrose (manufactured by Kishida Chemical Co., Ltd.) was added to 100 mL of ion-exchanged water and dissolved in a hot water bath to prepare a sucrose concentrate. 31 g of the sucrose concentrate and 6 mL of Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a centrifuge tube to prepare a dispersion. 1 g of toner was added to this dispersion, and toner clumps were broken down using a spatula or the like. The centrifuge tube was shaken at 5.8 s-1 for 20 minutes using a shaker.

[0132] After shaking, the solution is transferred to a glass tube (50 mL) for a swing rotor and centrifuged in a centrifuge at 58.3 s-1 for 30 min. Visually confirm that the toner and aqueous solution are sufficiently separated, and collect the toner that has separated to the top layer with a spatula or similar. The collected aqueous solution containing the toner is filtered using a vacuum filter, and then dried in a dryer for at least 1 hour to obtain a sample.

[0133] For these samples before and after washing, SEM / EDS observation is performed on a field of view aligned with the center of 20 randomly selected toner particles under the following conditions, and the total area of ​​the hydrotalcite particles is calculated. The adhesion rate of the hydrotalcite particles is calculated using the following formula: Adhesion rate of hydrotalcite particles (%) = (total area of ​​hydrotalcite particles of toner after washing) / (total area of ​​hydrotalcite particles of toner before washing) × 100

[0134] The SEM / EDS equipment and observation conditions were as follows: Equipment used (SEM): ULTRA PLUS manufactured by Carl Zeiss Microscopy K.K. Equipment used (EDS): NORAN System 7, Ultra Dry EDS Detector manufactured by Thermo Fisher Scientific K.K. Acceleration voltage: 5.0 kV WD: 7.0 mm Aperture size: 30.0 μm Detection signal: SE2 (secondary electrons) Observation magnification: 50,000x Mode: Spectral Imaging Pretreatment: Sample toner was spread on carbon tape and platinum sputtered.

[0135] The present disclosure will be described in more detail below with reference to examples and comparative examples, but the present disclosure is not limited thereto. The "parts" used in the examples are based on mass unless otherwise specified. A toner production example will be described below.

[0136] <Production Example of Toner Particles> <Preparation of Aqueous Dispersion Medium> The above aqueous solution was prepared and stirred at high speed while maintaining the temperature at 60° C. to prepare an aqueous sodium phosphate solution. Next, the following components were added to the above aqueous sodium phosphate solution and stirred at high speed to prepare an aqueous dispersion medium containing calcium phosphate fine particles.

[0137] <Preparation of Polymerizable Monomer Composition 1> Styrene 30.0 parts C.I. Pigment Blue 15:3 6.0 parts Charge control agent (aluminum complex) 0.5 parts The above materials were dispersed in an attritor at room temperature for 5 hours to obtain Polymerizable Monomer Composition 1.

[0138] <Preparation of polymerizable monomer composition 2> Polymerizable monomer composition 1 46.8 parts Styrene 39.0 parts n-butyl acrylate 25.0 parts Polar resin 1 10.0 parts (styrene-methacrylic acid-methyl methacrylate-2-hydroxyethyl methacrylate copolymer, Mw = 15200) Polar resin 2 4.0 parts (polyester resin which is a polycondensation product of propylene oxide-modified bisphenol A and terephthalic acid, Mw = 9500) Polar resin 3 1.0 part (styrene-2-ethylhexyl acrylate copolymer containing 10% by mass of 2-acrylamido-2-methylpropanesulfonic acid, Mp = 18000) Behenyl behenate 6.0 parts Hydrocarbon wax (melting point 78 ° C) 3.0 parts The above materials were charged into a temperature-controllable stirring tank, heated to 60° C., and stirred for 1 hour to obtain a polymerizable monomer composition 2.

[0139] <Granulation and polymerization step> The polymerizable monomer composition 2 was added to an aqueous dispersion medium, and 7.0 parts of a polymerization initiator was further added. Granulation was carried out for 10 minutes while maintaining high-speed stirring at a temperature of 60°C. Thereafter, the stirrer was changed to a propeller stirrer, and the mixture was heated to 70°C and reacted for 5 hours. The mixture was further heated to 80°C and reacted for 5 hours, and then cooled to obtain a polymer microparticle dispersion.

[0140] <Washing, drying, and classification steps> 10% hydrochloric acid was added to the above polymer particle dispersion to dissolve the calcium phosphate particle dispersant, and the resultant was filtered, washed, dried, and classified using an air classifier to obtain toner particles having a weight average particle size of 5.8 μm.

[0141] <Preparation of Hydrotalcite Particles 1> Sodium fluoride 3.5 parts Water 350.0 parts

[0142] The above aqueous solution was prepared, and 3.5 parts of hydrotalcite (primary particle number average particle size: 240 nm) was added. The mixture was stirred at room temperature for 10 hours, filtered, dried, and crushed to obtain hydrotalcite particles 1. Line analysis in STEM-EDS mapping analysis confirmed the presence of fluorine inside hydrotalcite particles 1, with F / Al = 0.11 and Mg / Al = 2.45.

[0143] <Hydrotalcite Particles 2> The hydrotalcite (primary particle number average particle size 240 nm) used in preparing the hydrotalcite particles 1 was designated as hydrotalcite particles 2. In line analysis in the STEM-EDS mapping analysis, the presence of fluorine inside the hydrotalcite particles 2 could not be confirmed.

[0144] <Preparation of Hydrotalcite Particles 3> Methanol 50.0 parts Fluorine-containing silicone (X-12-2430C, manufactured by Shin-Etsu Silicones Co., Ltd.) 0.3 parts Hydrotalcite (number average particle size of primary particles 240 nm) 5.0 parts The above materials were added and stirred at room temperature for 10 hours, and then 500 parts of water was added and stirred for another hour, followed by filtration, drying, and crushing to obtain Hydrotalcite Particles 3. In line analysis in STEM-EDS mapping analysis, the presence of fluorine could not be confirmed inside the Hydrotalcite Particles 3, but the presence of fluorine was confirmed on the surface of the Hydrotalcite Particles 3.

[0145] <Production Example of Toner 1> To the toner particles (100.0 parts) obtained above, hydrotalcite particles 1 (0.3 parts) and hydrophobic treated silica (BET 380 m ２ The resulting mixture was externally added and mixed in a Mitsui Henschel mixer (Mitsui Miike Chemical Engineering Co., Ltd.). The external addition conditions were adjusted such as the stirring rotation speed and mixing time so as to achieve a desired adhesion rate.

[0146] Thereafter, the mixture was sieved through a mesh having an opening of 200 μm to obtain Toner 1. The adhesion rate of the hydrotalcite particles to the toner particles was 30%.

[0147] <Production Example of Toner 2> Toner 2 was obtained in the same manner as in Production Example of Toner 1, except that the hydrotalcite particles used in Production Example of Toner 1 were changed to Hydrotalcite Particles 2.

[0148] <Production Example of Toner 3> Toner 3 was obtained in the same manner as in Production Example of Toner 1, except that the hydrotalcite particles used in Production Example of Toner 1 were changed to Hydrotalcite Particles 3.

[0149] [Confirmation of the Effects of the Invention] For each of the above toner and the developing blade 35 with and without the "capture area J" at the leading edge, 5,000 sheets of paper were continuously printed with a horizontal line at an image ratio of 1% under conditions of a temperature of 15°C and a humidity of 10% RH, and the effects were confirmed. The toner of this example is Toner 1, and the toners of the comparative examples are Toner 2 and Toner 3.

[0150] To verify the effect, a reflection densitometer (Model TC-MOR-45, manufactured by Tokyo Denshoku Co., Ltd., using a green filter) was used to measure the reflectance (%) in order to measure the fog density caused by poor regulation. Fog measurement was performed by attaching a post-it note or the like to a part of the paper to be printed, forming a plain image, and outputting the paper. Fog measurement was performed using the reflectance of the part of the output paper from which the attached post-it note was removed as the reference reflectance of the paper itself. Reflectance differs depending on the part measured, and the difference between the measured value of the part with the smallest value and the measured value (reference reflectance) of the part with the post-it note attached was measured as the fog value. The smaller the measured fog value, the less fog there was, and the better the image quality.

[0151] Further, a solid black image was formed on the entire surface, and the image density was measured using a densitometer (manufactured by eXact x-rite).

[0152] In this evaluation, when Toner 2 and Toner 3 were used, when the developing blade 35 was used with a "capture area J" at the leading edge, and when the developing blade 35 was used without a "capture area J" at the leading edge, when the developing roller 25 was brought into contact to obtain the desired image density, fogging due to poor regulation occurred to a level that was intolerable for practical use. The desired density was a densitometer reading of 1.3, and the level of fogging that was intolerable for practical use was fogging of 5% or more. It is believed that the poor regulation occurred with the toner that does not contain fluorine because excessive charge was imparted by the hydrotalcite particles.

[0153] Furthermore, when a developing blade 35 that does not have a sufficient "capture area J" at the leading edge of the toner 1 was used, when the developing roller 25 was brought into contact with the toner 1 to obtain the desired image density, a level of regulation failure that was unacceptable for practical use occurred.

[0154] On the other hand, when using toner 1 and the developing blade 35 provided with the "capture area J" at the leading edge, the desired image density was obtained and the occurrence of regulation failure was suppressed.

[0155] In other words, by using toner to which fluorine-containing hydrotalcite is externally added and a developing blade 35 provided with an "intake area J" at the leading edge, it is possible to obtain good image quality.

[0156] In this embodiment, the case where the developing blade 35 has the "capture area J" formed by polishing the leading edge portion thereof has been described, but the present invention is not limited to this.

[0157] For example, a similar effect can be obtained by using a developing blade 35 whose leading edge is bent at a predetermined radius of curvature, as shown in Fig. 10. Even when using a developing blade 35 whose leading edge is bent as shown in Fig. 10, a point F on the developing blade 35 exists in the "take-in area J" of the leading edge of the developing blade 35, which is farther away from the developing roller 25 than the volume average particle size R of the toner, and the width d2 of the take-in area on the free end side of point F is larger than the volume average particle size R of the toner, so it is thought that a similar effect can be obtained.

[0158] The present invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to clarify the scope of the present invention. This application claims priority based on Japanese Patent Application No. 2023-103626, filed on June 23, 2023, the entire contents of which are incorporated herein by reference.

[0159] 1: photosensitive drum, 25: developing roller, 31a: toner storage chamber, 31b: developing chamber, 34: toner supply roller, 36: toner transport member, 70: process cartridge, 811: first portion, 812: second portion, 813: third portion

Claims

1. A process cartridge that can be mounted in an image forming apparatus, comprising: a photosensitive drum as an image carrier; a developing roller for developing a toner image on the photosensitive drum; a supply roller for supplying toner to the developing roller; a developing chamber having a support portion for axially supporting the developing roller and the supply roller; a developing blade for regulating the layer thickness of the toner on the developing roller; a toner containing toner particles having a volume average particle size R and an external additive; and a toner containing portion for containing the toner, the toner containing portion is configured to communicate with the developing chamber via a communication port; the direction of movement of the surface of the developing roller is opposite to the direction of movement of the surface of the supply roller at the contact position with the supply roller; in a cross section of the process cartridge in a plane perpendicular to the rotation axis of the developing roller when mounted in the main body of the image forming apparatus, the point where the developing blade contacts the developing roller is vertically below a horizontal line H1 passing through the center of the rotation axis of the developing roller; and a drive force receiving portion, a first driving force transmission section for transmitting a driving force from the driving force receiving section to the supply roller, a second driving force transmission section provided on the supply roller for transmitting the driving force received by the first driving force transmission section to the developing roller, and a third driving force transmission section provided on the developing roller for transmitting the driving force from the second driving force transmission section to the developing roller, wherein the toner has hydrotalcite particles as the external additive, and in a line analysis in a STEM-EDS mapping analysis of the toner, fluorine is present inside the hydrotalcite particles, the developing blade is composed of a plate-shaped metallic elastic blade and a blade support section for supporting the elastic blade, and in a cross section of the process cartridge taken on a plane perpendicular to the rotation axis of the developing roller, the elastic blade forms a nip N1 and is in contact with the developing roller, and a point on the elastic blade at the end upstream in the rotation direction of the developing roller at the nip N1 is designated as point D, and a point on the elastic blade that is the freest end side and closest to the surface of the developing roller is designated as point B, A point E is a point where a perpendicular line drawn from point B to the surface of the developing roller intersects with the surface of the developing roller.a point F on the surface of the elastic blade that is closest to the free end of the elastic blade and has a distance R from the surface of the developing roller; and a point G on a straight line BE that is a distance R from the surface of the developing roller, the distance GF being equal to or greater than R.

2. A process cartridge that can be installed in an image forming apparatus, comprising: a photosensitive drum as an image carrier; a developing roller for developing a toner image on the photosensitive drum; a supply roller for supplying toner to the developing roller; a developing chamber having a support portion for axially supporting the developing roller and the supply roller; a developing blade for regulating the layer thickness of the toner on the developing roller; a toner containing toner particles having a volume average particle size R and an external additive; and a toner containing portion for containing the toner, the toner containing portion being configured to communicate with the developing chamber via a communication port, the direction of movement of the surface of the developing roller is opposite to the direction of movement of the surface of the supply roller at the position of contact with the supply roller, the developing blade being composed of a plate-shaped metallic elastic blade and a blade support portion for supporting the elastic blade, and in a cross section of the process cartridge taken on a plane perpendicular to the axis of rotation of the developing roller, a first driving force transmission section for transmitting a driving force from the driving force receiving section to the supply roller; a second driving force transmission section provided on the supply roller for transmitting the driving force received at the first driving force transmission section to the developing roller; and a third driving force transmission section provided on the developing roller for transmitting a driving force from the second driving force transmission section to the developing roller, wherein the toner has hydrotalcite particles as the external additive, and in a line analysis in a STEM-EDS mapping analysis of the toner, fluorine is present inside the hydrotalcite particles, and in a cross section of the process cartridge in a plane perpendicular to the rotation axis of the developing roller, The elastic blade is in contact with the developing roller to form a nip N1, and a point on the elastic blade at an end on the upstream side in the rotation direction of the developing roller in the nip N1 is defined as point D,A process cartridge characterized in that, when point B is the point on the free end side of the elastic blade and closest to the surface of the developing roller, point E is the point where a perpendicular line drawn from point B to the surface of the developing roller intersects with the surface of the developing roller, point F exists on the surface of the elastic blade which is closest to the free end side of the elastic blade and has a distance R from the surface of the developing roller, and point G is a point on a line BE which has a distance R from the surface of the developing roller, the distance GF is equal to or greater than R.

3. The process cartridge according to claim 1 or 2, wherein when a tangent to a point F on the surface of the elastic blade is a straight line L4, an angle θ formed by the straight line L4 and a straight line DE is in the range of 0°<θ<45°.

4. The process cartridge according to claim 3, wherein the angle θ is in the range of 0°<θ<25°.

5. A process cartridge according to claim 1 or 2, characterized in that the distance between any point on said elastic blade between said point D and said point B and the surface of said developing roller increases as the point moves away from said point D.

6. The process cartridge according to claim 1 or 2, wherein the FG distance is 20 μm or more.

7. The process cartridge according to claim 1 or 2, further comprising a second driving force receiving portion for transmitting a driving force to at least said photosensitive drum.

8. The process cartridge according to claim 1 or 2, characterized in that the developing roller and the supply roller are drivingly connected to rotate by the driving force from the driving force receiving portion such that the peripheral speed ratio R shown in the following formula (E1) satisfies R > 1.0: R = Vrs / Vd ... (E1) (in formula (E1), Vrs represents the absolute value of the peripheral speed of the supply roller [mm / sec], and Vd represents the absolute value of the peripheral speed of the developing roller [mm / sec]).

9. The process cartridge according to claim 1 or 2, characterized in that, when the radius of the developing roller is Rd [mm] and the radius of the supply roller is Rrs [mm], the second driving force transmission portion and the third driving force transmission portion are drivingly connected so that the rotational angular velocity ratio λ expressed by the following formula (E2) satisfies λ×Rrs / Rd>1.0: λ=ωrs / ωd...(E2) (in formula (E2), ωrs represents the rotational angular velocity [rad / sec] of the supply roller, and ωd represents the rotational angular velocity [rad / sec] of the developing roller).

10. The process cartridge according to claim 1 or 2, characterized in that there is no stirring member for stirring the toner in said developing chamber.

11. The process cartridge according to claim 1 or 2, wherein, of the members supported in said developing chamber, the members supported so as to be capable of transmitting the driving force from said driving force receiving portion are only the developing roller and the supply roller.

12. A process cartridge as described in claim 1 or 2, characterized in that, when attached to the main body of the image forming apparatus, the elastic blade is supported so as to be flexible between the supported end supported by the blade support portion and the other free end, and if a horizontal line passing through the supported end is taken as a straight line H2, at least a part of the inner wall of the developing chamber located vertically below the supply roller is located vertically above the straight line H2, between two tangents that extend vertically among the tangents that contact the outer circumferential surface of the supply roller.

13. The process cartridge according to claim 1 or 2, further comprising a transport member for transporting toner, the transport member having elasticity and transporting the toner by rotating, the transport member being rotatably supported in the toner storage chamber.

14. In an installed state in which the toner conveying member is installed in the main body of the image forming apparatus, the communication opening is disposed above the toner storage section, the conveying member is a member that has elasticity and conveys the toner by rotating, and has a deformation section that is provided in the toner storage section so as to come into contact with the free end side of the conveying member at a position upstream of the communication opening in the rotation direction of the conveying member, and that deforms the conveying member against the elasticity as the conveying member rotates so that the free end side is more upstream in the rotation direction of the conveying member than the rotation shaft side, and a restoration section that is provided in the toner storage section at a position downstream of the deformation section in the rotation direction of the conveying member and upstream of the communication opening in the rotation direction of the conveying member so that the tip of the free end side of the conveying member is released from contact, and that restores the conveying member deformed by the deformation section by the elasticity in order to cause the toner on the conveying member to fly to the communication opening, and in the installed state, a boundary section between the deformation section and the restoration section is provided below a lower end of the communication opening, The process cartridge according to claim 13, characterized in that, when viewed from the axial direction of the developing roller, the center of rotation of the transport member and the center of rotation of the developing roller are on the same side of a vertical line passing through the boundary portion, and a maximum value of the radius of rotation of the transport member is greater than the distance between the center of rotation of the transport member and a lower end of the communication port.

15. The process cartridge according to claim 13, wherein the conveying member comprises a rotating shaft and a flexible sheet member fixed to the rotating shaft, and the sheet member is fixed at a plurality of different phases centered on the agitating shaft.

16. A process cartridge as claimed in claim 1 or 2, characterized in that the tip shape of said elastic blade, at which point D exists, is formed by polishing the surface of said elastic blade.

17. A process cartridge as described in claim 1 or 2, characterized in that the tip shape of the elastic blade at which point D exists is formed by bending the tip of a metal plate-shaped elastic member in the direction opposite to the developing roller contact surface side.

18. The process cartridge according to claim 1 or 2, characterized in that in a line analysis in a STEM-EDS mapping analysis of the toner, fluorine and aluminum are present inside the hydrotalcite particles, and the ratio (F / Al) of the atomic concentration (atomic %) of the fluorine in the hydrotalcite particles to the atomic concentration (atomic %) of the aluminum in the hydrotalcite particles, obtained from main component mapping of the hydrotalcite particles by the STEM-EDS mapping analysis of the toner, is 0.01 to 0.

65.

19. The process cartridge according to claim 1 or 2, wherein the adhesion rate of the hydrotalcite particles to the toner particles is 10% or more.

20. The process cartridge according to claim 1 or 2, characterized in that the hydrotalcite particles contain magnesium.

21. The process cartridge according to claim 20, wherein the ratio (Mg / Al) of the atomic concentration (atomic %) of magnesium to the atomic concentration (atomic %) of aluminum in said hydrotalcite particles is 1.5 to 4.

0.

22. The process cartridge according to claim 1 or 2, wherein the number average particle size of the primary particles of the hydrotalcite particles is 60 to 1,000 nm.

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