Developing device

Abstract

To develop cartridges or electrophotographic image forming apparatuses. [Solution] A developing apparatus comprising a frame having a housing for containing a developer, a first electrode section and a second electrode section used for detecting capacitance inside the housing section, a rotating shaft that rotates about a rotation axis extending in a first direction, a fixed end fixed to the rotating shaft, and a free end opposite the fixed end in a second direction perpendicular to the rotation axis, wherein the length from the fixed end to the free end is long enough to contact the inner wall of the frame forming the housing section, wherein a part of the inner wall has a recess that is recessed in a direction away from the rotation axis in the second direction, the first electrode section and the second electrode section are provided in the recess, the width of the recess in the first direction is narrower than the width of the agitated sheet in the first direction, and the recess in the first direction is in the region between both ends of the agitated sheet.

Description

Technical Field

[0001] The present invention relates to a developing device used in an electrophotographic image forming apparatus. Background Art

[0002] Conventionally, a capacitance method is widely known as a remaining toner amount detection means for detecting the remaining amount of toner in a toner storage portion of a process cartridge and a toner cartridge. In the capacitance method, at least two electrodes are arranged in the toner storage portion to form a capacitor, and the remaining amount of toner is detected by detecting a change in capacitance between the capacitor electrodes. Of the two electrodes forming the capacitor, the first electrode is supplied with an AC voltage, and the second electrode is connected to a current detection circuit. The remaining amount of toner is detected by detecting the displacement current flowing through the capacitor by the AC voltage with the current detection circuit. A configuration in which a conductive sheet is fixed to a developer storage frame as a capacitor electrode in a toner storage portion has been proposed (Patent Document 1). Prior Art Literature Patent Literature

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. 2023-174061 Summary of the Invention Problem to be Solved by the Invention

[0004] An object of the present disclosure is to develop a cartridge or an electrophotographic image forming apparatus. Means for Solving the Problem

[0005] In order to solve the above problem, the developing device of the present invention comprises: A developing device, comprising: a frame body having a storage portion for storing developer; Inside the housing, a first electrode portion and a second electrode portion are exposed from the frame and arranged to face each other, The stirring member comprises a rotating shaft that rotates about a rotation axis extending in a first direction, and a sheet whose end in a second direction perpendicular to the first direction is fixed to the rotating shaft and is a fixed end, and whose end opposite to the fixed end in the second direction is a free end, and whose length from the fixed end to the free end is a length that allows it to contact the inner wall of the frame that constitutes the housing, A portion of the inner wall of the frame has a recess that is recessed in the direction away from the axis of rotation in the second direction, The first electrode portion and the second electrode portion are provided in the recess, The width of the recess in the first direction is narrower than the width of the sheet in the first direction, and the recess is located in the region between the ends of the sheet in the first direction. [Effects of the Invention]

[0006] According to this disclosure, a cartridge or electrophotographic image forming apparatus can be developed. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of a developing unit according to an embodiment of the present invention [Figure 2] Cross-sectional view of the detection capacitor in an embodiment of the present invention [Figure 3] Cross-sectional view of the main body of the image forming apparatus [Figure 4] Cross-section of a process cartridge [Figure 5] Perspective view of the process cartridge [Figure 6] Perspective view of an electrode holder that holds the first and second electrodes. [Figure 7] Perspective view showing the relative positions of the process cartridge and laser scanner. [Figure 8] Perspective view of frame members [Figure 9] Perspective view of the second substrate, substrate holder, first spring, and second spring. [Figure 10] Diagram illustrating the relative positions of the developing unit, the first electrical contact, and the second electrical contact. [Figure 11] Cross-sectional view showing the formation method (primary molding) of a sensing capacitor by conductive two-color molding. [Figure 12] Cross-sectional view showing the method of forming a sensing capacitor by conductive two-color molding (secondary molding). [Figure 13] Cross-sectional view showing the method of forming a sensing capacitor by conductive two-color molding (release mechanism). [Figure 14] Cross-sectional view showing remaining inspection components and toner sealing configuration. [Figure 15] Cross-sectional view showing the configuration of electrical contacts and developing contacts. [Figure 16] Perspective view showing resin flow path and gate arrangement configuration in conductive resin molding. [Figure 17] Perspective view showing resin flow path and gate arrangement configuration in conductive resin molding. [Figure 18] This diagram illustrates the capacitance simulation results for this example and comparative example. [Figure 19] Cross-sectional view showing a comparative configuration of the sensing capacitor for this embodiment. [Figure 20] Block diagram of the wiring configuration for the high-voltage circuit, detection circuit, and process cartridge. [Figure 21] Equivalent circuit diagram showing the configuration in Figure 20 using circuit constants. [Figure 22] Time-series diagram of toner level detection signals [Modes for carrying out the invention]

[0008] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of this invention is not intended to be limited to the following embodiments. Furthermore, although each embodiment describes multiple features, not all of these features are necessarily essential to the invention, and the features may be combined arbitrarily. In addition, in the attached drawings, the same or similar components are given the same reference numeral, and redundant descriptions are omitted.

[0009] Here, a developing unit refers to a device that has at least one of the following components: toner, a toner storage unit, a developer carrier, and a process means that acts on the developer carrier, and is detachable from the main body of an electrophotographic image forming apparatus (hereinafter referred to as the "apparatus body"). Typical examples of developing units include developing cartridges, process cartridges, and toner cartridges. A developing cartridge is a cartridge containing a developer carrier and a process means that acts on the developer carrier, which is detachably mounted on the apparatus body. A process cartridge is a cartridge containing an image carrier and a process means that acts on the image carrier, which is detachably mounted on the apparatus body. A toner cartridge contains a developer (hereinafter referred to as "toner") supplied to developing means such as a developer carrier, and is detachably mounted on the apparatus body. Furthermore, an electrophotographic image forming apparatus is a device that forms images on a recording medium using an electrophotographic image forming method. Examples of electrophotographic image forming apparatuses include, for example, electrophotographic copiers, electrophotographic printers (LED printers, laser beam printers, etc.), facsimile machines, and word processors.

[0010] (Example 1) <Overall Overview of the Image Forming Apparatus> Figure 3 is a cross-sectional view showing the schematic configuration of a monochrome laser printer, which is an example of an image forming apparatus. The main body of the image forming apparatus shown in Figure 3 (hereinafter referred to as the main body 101) is broadly divided into a sheet feeding unit, an image forming unit that forms an image on the sheet, a fixing unit, a paper discharge reversal unit, and a double-sided transport unit. Here, the horizontal directions in the image forming orientation of the main body 101 are denoted as X1 and X2, and the vertical directions as Y1 and Y2. Also, as shown in Figure 5, the horizontal directions are X1 and X2 and the vertical direction is Y 1. The longitudinal directions Z1 and Z2 are defined as directions perpendicular to Y2. The apparatus body 101 is equipped with a process cartridge 15 that is detachable from the apparatus body 101. The process cartridge 15 is a process unit for forming a toner image on a sheet S using an electrophotographic process, and has process means such as a photosensitive drum 48 as an image carrier, a charging roller 47, and a developing roller 46 as a developer carrier. Here, the mounting directions of the process cartridge 15 to the apparatus body 101 are defined as X7 and X8, and the mounting directions perpendicular to Y7 and Y8.

[0011] A laser scanner 106 is positioned above the process cartridge 15 and performs exposure on the photosensitive drum 48 based on an image signal. The photosensitive drum 48 is charged to a predetermined negative potential by a charging roller 47. Subsequently, the laser scanner 106 scans the photosensitive drum 48 with laser light, forming an electrostatic latent image on the photosensitive drum 48. Then, toner is supplied from the developing roller 46 onto the photosensitive drum 48 and developed, making it visible as a toner image.

[0012] The sheet feeding unit has a paper feed roller 141 mounted on the main body 101 of the device and a paper feed cassette 104 that is detachable from the main body 101 of the device. Sheets S contained in the paper feed cassette 104 are separated and fed one by one by the paper feed roller 141. The fed sheets S are transported by a transport roller pair 142 to a registration roller pair 144, where the registration roller pair 144 corrects for skew and then transports them to the transfer unit.

[0013] In the transfer section, a positive bias is applied to the transfer roller 125 by a bias application means (not shown). As a result, the toner image on the photosensitive drum 48 is transferred to the sheet S transported to the transfer section.

[0014] The sheet S onto which the toner image has been transferred is transported to a fixing device 103 located downstream in the transport direction from the transfer unit. The fixing device 103 fixes the toner image transferred to the sheet S to the sheet and has a heating unit 149 equipped with a heater, which is a heating means (not shown), and a pressure roller 150, which is a pressing member that rotates in contact with the heating unit 149. The sheet S on which the toner image has been formed is held and transported by a nip formed by the heating unit 149 and the pressure roller 150, and the toner image is fixed to the surface of the sheet S by the application of heat and pressure.

[0015] The sheet S, on which the toner image has been fixed, is ejected from the machine by the paper output roller pair 151.

[0016] <Entire process cartridge> The overall configuration of the process cartridge 15 will be explained using Figures 4 to 6(b). Figure 4 is a cross-sectional view of the process cartridge 15, and Figure 5 is a perspective view of the process cartridge 15. Figure 6(a) is a perspective view of the electrode holder 69 that holds the first electrode 61 and the second electrode 62. Figure 6(b) is a perspective view of the state shown in Figure 6(a) with the electrode holder 69 removed.

[0017] The process cartridge 15 consists of a cleaning unit 40 equipped with a photosensitive drum 48 and a developing unit 50 equipped with a developing roller 46, and is detachable from the main body 101 of the apparatus.

[0018] The cleaning unit 40 includes a photosensitive drum 48, a drum support member 42 that rotatably supports the photosensitive drum 48 around a rotation axis 41, a cleaning blade 43, and a waste toner storage section 44. The photosensitive drum 48 is rotatably supported around the rotation axis 41 by the drum support member 42. The charging roller 47 is positioned to contact the outer circumferential surface of the photosensitive drum 48 and charges the photosensitive drum 48 by applying voltage from the device body 101. The charging roller 47 also rotates in a driven manner relative to the photosensitive drum 48. The cleaning blade 43 elastically contacts the photosensitive drum 48 with its tip, thereby transferring the sheet S between the photosensitive drum 48 and the transfer roller. The transfer residue toner (hereinafter referred to as waste toner) remaining on the photosensitive drum 48 after passing between 125 is removed. The removed waste toner is stored in the waste toner storage unit 44.

[0019] The developing unit 50 includes a developing chamber 51 in which a developing roller 46, a supply roller 54, and a developing blade 55 are arranged, and a toner storage section 60 that supplies toner to the developing chamber 51. The developing roller 46 supplies toner to the developing area of ​​the photosensitive drum 48. The developing roller 46 then develops the electrostatic latent image formed on the photosensitive drum 48 using toner (developer). The developing blade 55 contacts the developing roller 46 to control the amount of toner that adheres to the circumferential surface of the developing roller 46 and simultaneously imparts a triboelectric charge to the toner. The supply roller 54 rubs against the developing roller 46 to supply toner from the developing chamber 51 to the developing roller 46 while scraping off excess toner adhering to the developing roller 46. The developing blade 55 contacts the circumferential surface of the developing roller 46 to control the amount of toner that adheres to the circumferential surface of the developing roller 46 and also imparts a triboelectric charge to the toner.

[0020] The toner contained in the toner storage section 60 is sent to the developing chamber 51 by the rotation of the stirring member 63 and supplied to the developing roller 46. The toner storage section 60 is also provided with a sensing capacitor C that constitutes capacitance. The frame of the developing unit 50 that constitutes the toner storage section 60 is provided with a first electrode 61 as a first electrode section and a second electrode 62 as a second electrode section, which are used to detect the capacitance inside the toner storage section 60, so as to be exposed to the toner storage section 60. The first electrode 61 and the second electrode 62 are provided to face each other with a space between them inside the toner storage section 60. More specifically, the inner wall of the developing frame 52 that forms the toner storage section 60 includes a first wall surface 57 with an opening 57a that connects the toner storage section 60 to the developing chamber 51, and a second wall surface 59 that is connected downstream of the first wall surface 57 in the rotation direction of the stirring member 63 (see Figure 1). A recess 58 is provided on the second wall surface 59, which is part of the inner wall of the developing frame 52, in a direction perpendicular to the longitudinal directions Z1 and Z2 (the rotation axis of the stirring member 63) (second direction), away from the rotation axis of the stirring member 63 (stirring axis 63a, described later) (see Figure 1). The first electrode 61 and the second electrode 62 are provided in this recess 58. The width of the recess 58 in the longitudinal directions Z1 and Z2 (first direction along the rotation axis of the stirring member 63) is defined by the first side wall 30 facing the same direction in the recess 58 and the second side wall 31 facing the same direction and facing the first side wall 30 in the same direction (see Figure 15). The first electrode 61 and the second electrode 62 are provided so as to extend in the longitudinal directions Z1 and Z2 between the first side wall 30 and the second side wall 31, respectively, so that the direction along the rotation axis of the stirring member 63 (first direction) is the longitudinal direction. In the rotational direction of the stirring member 63, the first electrode 61 is located on the upstream side, and the second electrode 62 is located on the downstream side. The first electrode 61 is provided such that, when viewed in the direction of the rotation axis of the stirring member 63 (first direction), it gradually moves away from the rotation axis of the stirring member 63 as it moves from the upstream side to the downstream side in the rotational direction of the stirring member 63. The second electrode 62 is provided such that, when viewed in the direction of the rotation axis of the stirring member 63 (first direction), it gradually moves closer to the rotation axis of the stirring member 63 as it moves from the upstream side to the downstream side in the rotational direction of the stirring member 63.The sensing capacitor C is formed from a first electrode 61 and a second electrode 62, which are arranged substantially parallel to the longitudinal directions Z1 and Z2. The rotation of the stirring member 63 causes toner to move in and out between the first electrode 61 and the second electrode 62. Due to this movement of toner inside the sensing capacitor C, the capacitance between the first electrode 61 and the second electrode 62 changes with the rotation period T of the stirring member 63. Age (Hereafter, stirring period T Age It changes depending on (what is called).

[0021] As shown in Figure 6(a), the electrode holder 69 has a first electrical contact 64 as a first electrical contact and a second electrical contact 65 as a second electrical contact, which are exposed to contact a spring (not shown) on the main body of the device, which will be described later. As shown in Figure 6(b), the first electrode 61 and the first electrical contact 64 in the developing unit 50 are configured to be electrically connected by being integrally molded with conductive resin. Similarly, the developing unit 50 has a first electrical contact and a second electrical contact 62 and a second electrical contact The electrical contacts 65 are configured to be electrically connected by being integrally molded from conductive resin. More specifically, the frame of the developing unit 50 is composed of an insulating part having insulating properties and a conductive part having conductive properties. The latter conductive part is integrally molded with the former insulating part so that it is exposed both inside (toner storage section 60) and outside the frame. The conductive part includes a first conductive part (first conductive member) in which the part exposed to the toner storage section 60 becomes the first electrode 61 and the part exposed to the outside of the frame becomes the first electrical contact 64, and a second conductive part (second conductive member) in which the part exposed to the toner storage section 60 becomes the second electrode 62 and the part exposed to the outside of the frame becomes the second electrical contact 65. The insulating part is divided into a part that pivotally supports the stirring member 63, etc. (first part) and a part that is composed separately from that part and into which the conductive part is integrally molded (second part), the former being the developing frame 52 and the latter being the electrode holder 69.

[0022] Next, the configuration of the apparatus body 101 in this embodiment will be described in detail using Figures 7(a) to 9(c). Figures 7(a) and 7(b) are perspective views showing the positional relationship between the process cartridge 15 and the laser scanner 106. Figure 8(a) is a perspective view of the frame member 107 seen from below, and Figure 8(b) is a view of Figure 8(a) with the cover member 93 removed. Figures 9(a) to 9(c) are perspective views of the second substrate 81, substrate holder 92, first spring 90, and second spring 91.

[0023] As shown in Figures 7(a) and 7(b), the laser scanner 106, positioned above the process cartridge 15 in the direction of gravity, is fixed to a metal frame member 107 positioned between the laser scanner 106 and the process cartridge 15. Fixing it to the metal frame member 107 allows the process cartridge 15 and the laser scanner 106 to be positioned with high rigidity and high precision. A first circuit board 71, including an AC voltage output circuit, is fixed above the frame member 107. A second circuit board 81 (see Figure 8(b)), including a current sensing circuit, is positioned below the frame member 107, and the second circuit board 81 is held by a circuit board holder 92. The first circuit board 71 and the second circuit board 81 are electrically connected by a cable (AC voltage line) 66. The second circuit board 81 will be described later. A duct 108 for cooling the photosensitive drum 48 is provided on the frame member 107. The cable (AC voltage line) 66 is routed along the duct 108 and connected to the second circuit board 81 through a hole 107a provided in the frame member 107, as shown in Figure 8(b). The second circuit board 81 and an engine controller (not shown) are connected by a cable (signal line) 68, which is routed through the hole 107a in the frame member, similar to the cable (AC voltage line) 66.

[0024] As shown in Figures 8(b) and 9(a) to 9(c), the substrate holder 92 also holds the first spring 90 and the second spring 91 (hereinafter referred to as electrical contact springs). The electrical contact springs 90 and 91 are torsion springs, and their fixed ends 90a and 91a are in contact with the second substrate 81. The free ends 90b and 91b of the electrical contact springs 90 and 91 contact the first electrical contact 64 and the second electrical contact 65 provided on the developing unit 50 with a predetermined pressure. The coil portions 90c and 91c of the torsion springs are positioned upstream of the contact portions 90b and 91b between the first electrical contact 64 and the second electrical contact 65 on the free end side with respect to the insertion direction of the process cartridge 15, and are configured to rotate in the torsion spring rotation direction R9 shown in Figure 9(b) in accordance with the insertion of the process cartridge 15. As shown in Figure 8(a), the substrate holder 92, the first spring 90, and the second spring 91 are covered by a cover member 93, and the contact portions 90b and 91b on the free end sides of the first spring 90 and the second spring 91 are exposed through holes 93a provided in the cover member 93. The contact portions 90b and 91b are shaped like a coil wound around one turn.

[0025] <Toner level detection circuit> The configuration of the toner remaining amount detection circuit K (hereinafter referred to as the remaining amount detection circuit K) in an embodiment of the present invention and , the toner remaining amount detection signal V obtained from the remaining amount detection circuit K (SNS(t)) (Hereafter, residual test signal V (SNS(t)) The residual detection circuit K will be explained using Figures 9(a) to 9(c), Figure 20, Figure 21, and Figures 22(a) to 22(c). Figure 20 is a block diagram showing the wiring configuration between the first substrate 71, the second substrate 81, and the process cartridge 15 in the residual detection circuit K. Figure 21 is an equivalent circuit diagram showing each element of the residual detection circuit K expressed in terms of electrical circuit constants. Figures 22(a) to 22(c) show the residual detection signal V obtained from the residual detection circuit K. (SNS(t)) This is a time-series diagram showing the timeline.

[0026] As shown in Fig. 20, the remaining amount detection circuit K is composed of a first substrate 71 (AC voltage output circuit), a process cartridge 15, and a second substrate 81 (current detection circuit). The first substrate 71 is electrically connected via a cable (AC voltage line) 66 and a first electrical contact 64 to a first electrode 61 that is one end side of a detection capacitor C provided on the process cartridge 15. A second electrode 62, which is the other end side of the detection capacitor C, is electrically connected to the second substrate 81 via a second electrical contact 65 and a remaining amount detection signal line 67. The second substrate 81 is electrically connected to an engine controller E C and is electrically connected thereto.

[0027] As shown in Fig. 21, the first substrate 71 is an AC voltage output circuit having an AC power supply, and outputs (V PP / 2)sin(2πft) AC voltage to the process cartridge 15. Here, V PP is the amplitude of the AC voltage, f is the frequency of the AC voltage, π is the circular constant, and t is elapsed time. The second substrate 81 is constituted by a half-wave rectification unit formed of two half-wave rectification diodes V f and a primary low-pass filter. The primary low-pass filter includes a reference voltage V Ref driven operational amplifier, a detection sensitivity resistor R f for current-voltage conversion, and a cutoff capacitor C f for noise suppression.

[0028] The AC voltage input to the process cartridge 15 is output as a displacement current I to the second substrate 81 side via a parasitic resistance R existing between the electrical contact springs 90 and 91 shown in Figs. 9(a) to 9(c) and the electrical contacts 64 and 65 shown in Fig. 20, and the detection capacitor C. The displacement current I is generated between the frame GND and wirings of other circuits, and has a stray capacitance C P Due to the influence thereof, a part of the displacement current I flows out of the remaining amount detection circuit K as a displacement current loss component I Loss . As a result, an effective displacement current component I, which is the residual between the displacement current I and the displacement current loss component I Loss Remain ​The effective component I of the displacement current input to the second substrate 81 is input to the second substrate 81. Remain The signal is half-wave rectified via a half-wave rectifier, and then the residual signal V is obtained through the current-to-voltage conversion action of a primary low-pass filter. (SNS(t)) The output is as follows. Applying Ohm's law and Kirchhoff's laws to the equivalent circuit shown in Figure 21, the residual signal V (SNS(t)) Solving for this, we obtain the following equation. TIFF2026147787000002.tif25170

[0029] As mentioned above, the capacitance of the sensing capacitor C is affected by the inflow and outflow of toner to the sensing capacitor C, and the stirring period T Age It changes periodically at time intervals. Therefore, as shown in Figure 22(a), the residual detection signal V (SNS(t)) The stirring period is T Age This results in a pulsating waveform that changes periodically by an amplitude of ΔV at time intervals. This residual signal V (SNS(t)) Engine controller E C The signal is digitally processed to calculate the amplitude ΔV and duty cycle. The correlation between the amplitude ΔV and duty cycle and the remaining toner amount in the process cartridge 15 is obtained in advance according to the form of the process cartridge 15, and the remaining toner amount is estimated by comparing it with the amplitude ΔV and duty cycle calculated during product use.

[0030] From the above equation, the stray capacitance C in the residual detection circuit K is P When becomes excessively high, the residual detection signal V is as shown in Figure 22(b). (SNS(t)) The allowable detection voltage V Cross When it exceeds the residual detection signal V (SNS(t)) Because clipping occurs, accurate toner level detection becomes impossible. Therefore, the wiring from the detection capacitor C to the second circuit board 81, that is, the conductive path from the second electrode 62 to the second electrical contact 65 and the remaining detection signal line 67, is provided with sufficient space between them and the frame GND and the wiring of other circuits, thereby reducing the stray capacitance C PIt is preferable to reduce this. Also, from the above equation, if the parasitic resistance R in the residual detection circuit K is excessively high, or if the capacitance of the detection capacitor C is excessively low, the residual detection signal V will be reduced as shown in Figure 22(c). (SNS(t)) If the amplitude ΔV is not sufficiently obtained, accurate toner level detection becomes impossible. Therefore, it is preferable to suppress the parasitic resistance R that occurs between the conduction path from the first electrical contact 64 to the first electrode 61 and the conduction path from the second electrode 62 to the second electrical contact 65, while ensuring sufficient capacitance of the sensing capacitor C.

[0031] <Arrangement of electrical contacts> The arrangement of electrical contacts 64 and 65 will be explained using Figures 6(a), 6(b), and 10. Figure 10 is a side view showing the positional relationship between the developing unit 50 and the electrical contacts 64 and 65. As shown in Figure 10, the developing unit 50 is provided with developing contacts 600 for supplying predetermined bias to the developing roller 46, the supply roller 54, and the developing blade 55, respectively. The developing contacts 600 consist of a developing roller contact 646 for supplying bias to the developing roller 46, a supply roller contact 654 for supplying bias to the supply roller 54, and a developing blade contact 655 for supplying bias to the developing blade 55. The developing unit 50 is pivotally supported so as to be able to swing around a developing unit pivot center 50a provided on the process cartridge 15. As a result, when the process cartridge is mounted on the device body 101 shown in Figure 3, the developing unit 50 can take on a contact state in which the developing roller 46 is in contact with the photosensitive drum 48, and a separated state in which the developing roller 46 is separated from the photosensitive drum 48. Switching between the contact state and the separated state is performed by the developing unit 50 rotating around the pivot center 50a due to pressure from a developing separation mechanism (not shown) provided on the main body 101 of the device. On the other hand, the rotation axis centers of the photosensitive drum 48 and the charging roller 47 are fixed when mounted on the main body 101 of the device. During the image forming operation, toner development is performed on the photosensitive drum 48 in the contact state, and by switching to the separated state when not in use after the image forming operation is completed, the contact pressure of the developing roller 46 on the photosensitive drum 48 can be released, thereby extending the lifespan of the developing roller 46.

[0032] The electrical contacts 64 and 65 contact the free ends 90b and 91b of the electrical contact springs 90 and 91 at the first electrical contact contact portion 64t and the second electrical contact contact portion 65t (hereinafter referred to as the electrical contact contact portion). The electrical contacts 64 and 65 are formed as surfaces connecting the first end portion 64a and the first end portion 65a of the first electrical contact (hereinafter referred to as the first electrical contact end) and the second end portion 64b and the second electrical contact end 65b (hereinafter referred to as the second electrical contact end). Here, the midpoints of the first end portions 64a and 65a and the second end portions 64b and 65b of the electrical contact are defined as the first electrical contact center portion 64c and the second electrical contact center portion 65c (hereinafter referred to as the electrical contact center portion), respectively. In addition, the line connecting the electrical contact centers 64c and 65c and the pivot center 50a is defined as the first line L1, and the line perpendicular to the first line L1 and passing through the pivot center 50a is defined as the second line L2.

[0033] Next, the axial directions passing through the first electrical contact ends 64a, 65a and the second electrical contact ends 64b, 65b are defined as the electrical contact parallel directions X5, X6, and the axial directions perpendicular to the electrical contact parallel directions X5, X6 are defined as the electrical contact perpendicular directions Y5, Y6. Furthermore, the line passing through the first electrical contact ends 64a, 65a and the pivot center 50a is defined as the third line L3, and the line passing through the second electrical contact ends 64b, 65b and the pivot center 50a is defined as the fourth line L4.

[0034] In this embodiment, the angle between the parallel directions X5, X6 of the electrical contacts and the mounting directions X7, X8 of the process cartridge 15 is set to 15° or less. However, from the viewpoint of miniaturizing the main body of the device 101 and suppressing contact wear due to fluctuations in electrical contact pressure when the process cartridge 15 is mounted, it is preferable to reduce the above angle as much as possible. Furthermore, it is preferable to arrange the electrical contact parts 64t, 65t so that they are close to the center of the electrical contacts 64c, 65c. This is from the viewpoint of ensuring the engagement amount between the electrical contacts 64, 65 and the free end sides 90b, 91b of the electrical contact springs 90, 91, taking into account component tolerances and creep deformation due to prolonged storage.

[0035] In this embodiment, the first line L1 is relative to the third line L3 and the fourth line L4. L1 ≤ L3 and L1 ≤ L4 It is designed to be such that the inclination of the contact surfaces of electrical contacts 64 and 65 is L3 <L1<L4 または L3> L1>L4 In this case, wear on the electrical contacts 64 and 65 due to fluctuations in contact pressure when switching between the contact and separated states of the developing unit 50 is suppressed, making it possible to extend the product's lifespan. In addition, since the increase in contact resistance due to wear on the electrical contacts 64 and 65 can be suppressed, the remaining inspection signal V (SNS(t)) This prevents the increase in parasitic resistance, which is a cause of attenuation. As a result, the residual detection signal V throughout the product life is maintained. (SNS(t)) This stabilization ensures accurate toner level detection.

[0036] In this embodiment, the contact surfaces of electrical contacts 64 and 65 are L1 <L3 かつ L1<L4 It is formed in a planar shape, L1=L3 and L1=L4 It is also possible to form it in an arc shape centered on the pivot center 50a. The contact surfaces of the electrical contacts 64 and 65 are more preferably formed in a planar shape from the viewpoint of cost reduction through simplification of shape and inspection.

[0037] <Arrangement configuration of electrical contacts and developing contacts> The developing roller 46 and the supply roller 54 are rotatably supported by a developing bearing 56 provided in the developing unit 50. Inside the developing bearing 56, developing contacts 600 and power supply paths from the developing contacts 600 to the developing roller 46, the supply roller 54, and the developing blade 55 are provided by two-color molding of conductive resin. The developing contacts 600, i.e., the developing roller contact 646, the supply roller contact 654, and the developing blade contact 655, are electrically connected to the developing roller 46, the supply roller 54, and the developing blade 55 via their respective power supply paths. The developing contacts 600 may be formed integrally with each power supply path by two-color molding of conductive resin, or they may be provided separately from each power supply path using metal sheet metal.

[0038] In this embodiment, the electrical contacts 64 and 65 are positioned opposite the developing contact 600, developing roller 46, supply roller 54, and developing blade 55, with the second line L2 as the boundary. Furthermore, in the image forming position of the process cartridge 15, the electrical contacts 64 and 65 are positioned above the developing contact 600 in the vertical direction Y1. In addition, the normal direction of the electrical contacts 64 and 65 is oriented in the direction Y5 perpendicular to the electrical contacts, and the vertical component of the direction Y5 perpendicular to the electrical contacts coincides with the vertical direction Y1.

[0039] In this embodiment, as shown in Figures 10 and 20, the residual detection circuit K, consisting of electrical contacts 64 and 65 and a detection capacitor C, is arranged in a first phase, and the developing circuit, consisting of a developing contact 600, a developing roller 46, a supply roller 54, and a developing blade 55, is arranged in a second phase, thus separating them. Therefore, the stray capacitance C between the residual detection circuit and the developing circuit is P Residual detection signal V (SNS(t)) This prevents clipping, enabling accurate toner level detection using the capacitive method. P From a suppression standpoint, electrical contacts 64 and 65 are developed contacts 60 It is preferable to position them as far away as possible from 0, and it is desirable to ensure a wiring distance of 5 mm or more in the overall power supply path of the residual inspection circuit K and the developing circuit. In addition, the normal of the developing contact 600 in this embodiment is in the longitudinal direction Z1, i.e., positioned longitudinally outward with respect to the process cartridge 15. In contrast, the electrical contacts 64 and 65 are provided above the developing contact 600 in the vertical direction Y1, and the vertical component of the electrical contact vertical direction Y5, which is the normal direction of the electrical contacts 64 and 65, coincides with the vertical direction Y1. Therefore, in the building space on the horizontal direction X1-vertical direction Y1 coordinate system, which is an arbitrary cross-section of the process cartridge 15, the electrical contacts 64 and 65 and the developing contact 600 are positioned separately with different normal directions. As a result, sufficient placement space can be secured for the electrical contacts 64 and 65 and the developing contact 600, taking into account component tolerances. As a result, when the device is mounted on the main body 101, the electrical contacts 64 and 65 and the developing contact 600 can establish a stable electrical connection without interfering with each other. In addition, the normals of the electrical contacts 64 and 65 and the developing contact 600 are positioned in directions different from the vertical direction Y2, which is downward in the direction of gravity. For example, there may be cases where the process cartridge 15 is removed from the main body 101 for reasons such as jamming during use and placed in another location such as a desk or workbench. Even in such cases, the risk of damage such as dents or scratches to the electrical contacts 64 and 65 and the developing contact 600 can be reduced.

[0040] Next, the arrangement of the electrical contacts 64, 65 and the developing contact 600 in the longitudinal directions Z1 and Z2 will be described using Figure 15. Figure 15 is a DD cross-sectional view of the electrical contacts 64, 65 and the developing contact 600 in Figure 10. As shown in Figure 15, the supply roller contact 654, which is part of the developing contact 600, is provided at the end of the developing unit 50 on the longitudinal direction Z1 side. The other developing contacts, the developing roller contact 646 and the developing blade contact 655, also have a common longitudinal arrangement with the supply roller contact 654. The second electrical contact 65 and the second spring 91 are positioned relative to the developing contact 600 at a longitudinal distance L between the electrical contact and the developing contact in the longitudinal directions Z1 and Z2. DevThey are arranged opposite each other with a distance of L between them. In addition, the second electrical contact 65 and the second spring 91 are positioned relative to the left side plate 110, which is the frame ground FG, at a longitudinal distance L between the electrical contact and the left side plate. TLS They are arranged opposite each other with a gap of L between them. The developing contact 600 is located relative to the left plate 110, with a longitudinal distance L between the electrical contact and the left plate. TLS and the longitudinal distance L between the electrical contact and the developing contact. Dev The difference is the longitudinal distance L between the developing contact and the left side of the plate. DLS They are positioned opposite each other with a certain distance between them.

[0041] Long distance L between electrical contacts and left-side panel TLS and the longitudinal distance L between the electrical contact and the developing contact. Dev The distance L is the longitudinal distance between the developing contact and the left side of the plate. DLS It is provided to be long in relation to this. Therefore, from the viewpoint of the longitudinal directions Z1 and Z2, there is stray capacitance C between the residual detection circuit K and the developing circuit, and between the residual detection circuit K and the left side plate 110. P Residual detection signal V (SNS(t)) This prevents clipping. Therefore, it becomes possible to accurately detect the remaining toner level using a capacitive method.

[0042] <Method for manufacturing remaining inspection component Z> A method for manufacturing the residual inspection member Z, which consists of a detection capacitor C and an electrode holder 69, will be explained using Figures 1(a) to 1(c) and Figures 11(a) to 13(b). Figure 1 is a cross-sectional view showing the configuration of the developing unit 50 and the detection capacitor C. Figures 11(a) to 13(b) are cross-sectional views showing the method of forming the residual inspection member Z by conductive two-color molding.

[0043] As shown in Figures 11(a) to 13(b), the sensing capacitor C is injection molded by a sensing capacitor mold cavity 200, which is a fixed mold, and a sensing capacitor mold core 201, which is a movable mold. The sensing capacitor mold core 201 consists of a sensing capacitor mold core base portion 210, a sensing capacitor mold first core back portion 211, and a sensing capacitor mold second core back portion 212. The sensing capacitor mold first core back portion 211 and the sensing capacitor mold second core back portion 212 are translatable relative to the sensing capacitor mold core base portion 210 in the clamping direction, which is perpendicular to the sensing capacitor nearest point X3 and X4. It is composed of.

[0044] First, as shown in Figure 11(a), the detection capacitor mold core 201 is moved toward the nearest detection capacitor in the direction X4 perpendicular to the detection capacitor relative to the detection capacitor mold cavity 200, and as shown in Figure 11(b), it is brought into contact with the detection capacitor mold cavity 200. In this state, the mold is clamped and the insulating resin, which is the first material to be molded, is molded in the mold, and as shown in Figure 11(c), the electrode holder 69 is formed (primary molding).

[0045] After the electrode holder 69 is formed, as shown in Figure 12(a), the first core back portion 211 and the second core back portion 212 of the detection capacitor mold are backed by a core back amount L toward the nearest point X3 to the detection capacitor. Coreback Move by a certain amount of time. Core back of the first core back section 211 of the detection capacitor mold creates a first core back space 221 within the mold. Similarly, core back of the second core back section 212 of the detection capacitor mold creates a second core back space 222 within the mold. When the conductive resin, which is the second material to be molded, is molded in this state, a detection capacitor C consisting of a first electrode 61 and a second electrode 62 is formed (secondary molding) as shown in Figure 12(b). The thickness of the detection capacitor C in the direction X4 perpendicular to the nearest detection capacitor is the amount of core back L. CorebackThis is approximately equal to the product of the molding shrinkage rate of the conductive resin. That is, the thicknesses of the first electrode 61 and the second electrode 62 in the direction normal to the detection capacitor connection walls 52a and 52b are approximately equal. As shown in Figure 13(a), the detection capacitor mold core 201 is moved toward the direction X3 perpendicular to the nearest detection capacitor after the detection capacitor C has been formed. Finally, as shown in Figure 13(b), the detection capacitor C moves toward the direction X3 perpendicular to the nearest detection capacitor relative to the detection capacitor mold cavity 200. As a result, the remaining detection member Z is released from the detection capacitor mold cavity 200 and the detection capacitor mold core 201, and the conductive two-color molding is completed.

[0046] The detection capacitor C is formed by the core back of the detection capacitor mold core 201, as shown in Figures 11(a) to 13(b). Therefore, the first electrode tip opposing surface 61b (first opposing surface) and the second electrode tip opposing surface 62b (second opposing surface) are formed parallel to each other with respect to the detection capacitor nearest neighbor perpendicular directions X3 and X4, which are the core back direction. With the above procedure, the conductive two-color molding of the residual detection member Z, consisting of the detection capacitor C and electrode holder 69, is completed.

[0047] <Configuration of remaining inspection component Z> As shown in Figures 1 and 15, the developing unit 50 is provided with a developing frame 52, an agitator 63, and a residual inspection member Z. The agitator 63 consists of an agitator shaft 63a and an agitator sheet 63b, and is pivotally supported on the developing frame 52 so as to be rotatable around the rotation axis center 63c of the agitator 53 (around the rotation axis of the agitator shaft 63a) toward the rotation direction R6 of the agitator sheet. One end of the agitator sheet is fixed to the agitator shaft 63a, and the other end is a free end that flexes along the inner wall of the toner storage section 60, agitating the toner during a cycle T AgeThe stirring is circulated and stirred periodically at time intervals. That is, one end of the stirring sheet 63b in the direction perpendicular to the axis of rotation (first direction) (second direction) is fixed to the stirring shaft 63a, and the other end in the direction perpendicular to the axis of rotation (second direction), i.e., the end opposite the fixed end, is a free end. The length from the fixed end to the free end is such that it can contact the inner wall (at least the first wall surface 57 and the second wall surface 59) of the developing frame 52 that forms the toner storage section 60.

[0048] The electrode holder 69 forming the residual detection member Z is integrally connected to two detection capacitor connection walls 52a and 52b provided on the developing frame 52. Meanwhile, the detection capacitor C shown in Figure 15 is integrally connected to the first detection capacitor connection side wall 52c and the second detection capacitor connection side wall 52d at both ends in the longitudinal directions Z1 and Z2. The detection capacitor C is integrally connected to the developing frame 52 along a closed curved connection surface consisting of detection capacitor connection walls 52a and 52b, a first detection capacitor connection side wall 52c, and a second detection capacitor connection side wall 52d. These connection surfaces (detection capacitor connection walls 52a and 52b, the first detection capacitor connection side wall 52c, and the second detection capacitor connection side wall 52d) are surfaces that are continuous with the outer wall of the developing frame 52 and are approximately parallel to the rotation axis of the stirring member 63.

[0049] Furthermore, the first electrode 61 that forms the sensing capacitor C has a first electrode tilt angle θ that is set to be greater than the angle of repose of the toner with respect to the horizontal directions X1 and X2. 61 They are arranged with the following inclination. The nearest proximity directions of the first electrode 61 and the second electrode 62 (hereinafter referred to as the sensing capacitor nearest proximity directions Y3 and Y4) are provided approximately parallel to the sensing capacitor connection wall surfaces 52a and 52b. In other words, the sensing capacitor nearest proximity perpendicular directions X3 and X4, which are perpendicular to the sensing capacitor nearest proximity directions Y3 and Y4, are provided approximately perpendicular to the sensing capacitor connection wall surfaces 52a and 52b. The distance L between the stirring center and the sensing capacitor connection inner wall is the distance from the rotation axis center 63c of the stirring member 63 to the inner wall side of the toner storage section 60 of the sensing capacitor connection wall surfaces 52a and 52b. BondSimilarly, the distance L between the stirring center and the starting end of the sensing capacitor is the distance from the rotation axis center 63c to the sensing capacitor connection wall surfaces 52a and 52b. Cap It is set to be shorter than the distance L between the stirring center and the inner wall connecting the sensing capacitor. Bond This is the distance from the rotation axis center 63c to the region of the inner wall of the developing frame 52 that corresponds to the detection capacitor connection wall surfaces 52a and 52b connected to the outer wall of the developing frame 52.

[0050] As shown in Figure 2(a), the first electrode 61 has a first electrode start end 61s (first start end) that is far from the second electrode 62 around the rotation axis of the stirring member 63, and a first electrode end 61e (first end) that is close to the second electrode 62. Similarly, the second electrode 62 has a second electrode start end 62s (second start end) that is far from the first electrode 61 around the rotation axis of the stirring member 63, and a second electrode end 62e (second end) that is close to the first electrode 61. The first electrode start end 61s, which is one end of the first electrode 61 in the direction Y3, Y4 closest to the sensing capacitor, is formed on substantially the same plane as the sensing capacitor connection wall surfaces 52a, 52b. Similarly, the second electrode start end 62s, which is one end of the second electrode 62 in the direction Y3, Y4 closest to the sensing capacitor, is also formed on substantially the same plane as the sensing capacitor connection wall surfaces 52a, 52b. Therefore, when the free end of the stirring sheet 63b follows the inner wall of the toner storage section 60 and transports the toner toward the detection capacitor C, in the direction of X3 and X4, which is the direction of the stirring sheet 63b's penetration into the inner wall of the toner storage section 60 and is perpendicular to the nearest detection capacitor, the detection capacitor C, i.e., the first electrode 61 and the second electrode 62, are located on the side further away from the free end of the stirring sheet 63b than the detection capacitor connection wall surfaces 52a and 52b. The first detection capacitor connection side wall 52c and the second detection capacitor connection side wall 52d shown in Figure 15 are formed on the same plane as the detection capacitor connection wall surfaces 52a and 52b shown in Figures 1, 2(a), and 2(b). Therefore, the aforementioned distance L between the stirring center and the inner wall of the detection capacitor connection Bond The distance L is the distance between the stirring center and the starting end of the sensing capacitor. Cap It satisfies the relationship that it is set to be shorter than [a certain value].

[0051] Furthermore, as shown in Figures 1 and 2(a), the first electrode 61 has a first electrode end 61e which is the other end side in the sensing capacitor nearest-near-contact directions Y3 and Y4. The first electrode 61 also has a first electrode exposed portion 61f formed between the first electrode start end 61s and the first electrode end 61e. On the other hand, the second electrode 62 has a second electrode end 62e which is the other end side in the sensing capacitor nearest-near-contact directions Y3 and Y4. The second electrode 62 also has an electrode protrusion 62a formed between the second electrode start end 62s and the second electrode end 62e, which is a projection that protrudes toward the first electrode 61 in the sensing capacitor nearest-near-contact direction Y4. The electrode protrusion 62a is formed from a second electrode tip facing surface 62b having normals to the sensing capacitor nearest-near-contact directions Y3 and Y4, and a second electrode shear surface 62t having normals to the sensing capacitor nearest-near-contact directions X3 and X4. The second electrode tip facing surface 62b is substantially parallel to the rotation axis of the stirring member 63, and the sensing capacitor connection wall surfaces 52a and 52b The end face of the second electrode end 62e extending in the normal direction is a surface substantially parallel to the first electrode tip opposing surface 61b, which is the end face of the first electrode end 61e. The electrode protrusion 62a is the corner of the second electrode 62, which is composed of the second electrode tip opposing surface 62b and the second electrode shear surface 62t connected thereto. Furthermore, the first electrode tip opposing surface 61b and the second electrode tip opposing surface 62b have regions that overlap each other when viewed in a direction perpendicular to the rotation axis of the stirring member 63 and along the sensing capacitor connection wall surfaces 52a and 52b. The shortest distance between the first electrode 61 and the second electrode 62 in the same direction is formed between the first electrode tip opposing surface 61b and the second electrode tip opposing surface 62b. That is, the electrode start end distance L Start This is the distance (Y3, Y4) in the direction closest to the sensing capacitor between the first electrode start end 61s and the second electrode start end 62s, in a direction perpendicular to the rotation axis of the stirring member 63 and along the sensing capacitor connection wall surfaces 52a and 52b. Also, the distance L between the electrode ends. End This is the distance Y3, Y4 in the direction closest to the sensing capacitor between the first electrode end 61e and the second electrode end 62e in the same direction. The distance L between the electrode start ends. Start The distance L between the ends of the electrodes is EndIt is provided to be longer than the first electrode end 61e and the second electrode end 62e are positioned on the side of X4 in the direction perpendicular to the nearest contact with the sensing capacitor, that is, on the side farther from the rotation axis center 63c of the stirring member 53, relative to the first electrode start end 61s and the second electrode start end 62s. The electrode protrusion distance L is the distance between the electrode protrusion 62a and the first electrode exposed portion 61f in the direction Y3, Y4 of nearest contact with the sensing capacitor. Ext The distance L between the ends of the electrodes is End and the distance L between the starting ends of the electrodes Start It is located between the electrodes. Electrode end distance L End This is the residual detection signal V obtained by ensuring the capacitance of the detection capacitor C. (SNS(t)) From the viewpoint of stabilizing the system and ensuring the strength of the detection capacitor mold core base portion 210 to maintain mass production capabilities, it is preferable to set it between 1 mm and 2.5 mm.

[0052] The first electrode 61 and the second electrode 62 of the sensing capacitor C are located in the sensing capacitor opposing region L, which is the X3 and X4 components in the direction perpendicular to the nearest point of contact with the sensing capacitor of the exposed portion 61f of the first electrode. Face In this configuration, the exposed portions of both are facing each other. On the other hand, the detection capacitor opposing region L Face In contrast, the non-opposing region L of the sensing capacitor is located adjacent to the nearest sensing capacitor in the vertical direction X4. Side A first non-opposing shielding wall 69b and a second non-opposing shielding wall 69c are provided. The first non-opposing shielding wall 69b and the second non-opposing shielding wall 69c are located at the distance L between the electrode ends in the direction closest to the sensing capacitor of the electrode holder 69 (Y3, Y4). End Within the region, a portion of the first electrode tip opposing surface 61b and the second electrode tip opposing surface 62b is shielded. Specifically, the first non-opposing shielding wall 69b is a wall portion (first wall portion) of the electrode holder 69 that contacts the first electrode tip opposing surface 61b and protrudes along the first electrode tip opposing surface 61b toward the rotation axis of the stirring member 63. Similarly, the second non-opposing shielding wall 69c is a wall portion (second wall portion) of the electrode holder 69 that contacts the second electrode tip opposing surface 62b and protrudes along the second electrode tip opposing surface 62b toward the rotation axis of the stirring member 63. The first non-opposing shielding wall 69b, like the first electrode exposed portion 61f, has a first electrode inclination angle θ 61It is arranged in such a way. In addition, the non-opposing region L of the sensing capacitor. Side , distance L between electrode ends End An electrode recess 69a, which is a space capable of accommodating toner and consisting of a region, a first non-opposing shielding wall 69b, and a second non-opposing shielding wall 69c, is provided between the first electrode 61 and the second electrode 62. The electrode recess 69a is recessed in a direction away from the rotation axis of the stirring member 63 between the first non-opposing shielding wall 69b and the second non-opposing shielding wall 69c. The first electrode 61 and the second electrode 62 are separated by an electrode end distance L End The electrode recess 69a, which has a gap, is electrically non-contact, thereby forming a sensing capacitor C.

[0053] The exposed portion 61f of the first electrode 61 in the toner storage section (storage chamber) 60 is set to a first electrode tilt angle θ that is greater than the angle of repose of the toner. 61 They are arranged in this manner. Therefore, after the stirring sheet 63b moves away from the sensing capacitor C in the direction Y3, the toner on the first electrode 61 falls in the vertical direction Y2 due to the action of gravity. For this reason, in the movement of toner into and out of the sensing capacitor C due to the rotation of the stirring member 63 shown in Figure 1, the toner that has entered between the first electrode 61 and the second electrode 62 This makes it possible to prevent accumulation. Furthermore, the electrode protrusion distance L is the distance between the electrodes of the sensing capacitor. Ext , distance L between electrode ends End , distance L between electrode starting ends Start These are formed by conductive two-color molding of the residual detection member Z shown in Figures 11(a) to 13(b). The distance between electrodes, which is a characteristic factor of the capacitance of the detection capacitor C, is determined by the precision of the two-color molding mold and the control of the molding conditions. Therefore, compared to cases where the capacitor electrodes are provided by assembling or attaching multiple parts, variations due to fitting play during assembly and attachment position tolerances can be eliminated. By suppressing the tolerance of the distance between electrodes, the residual detection signal V (SNS(t)) Because the amplitude ΔV in this region becomes more stable, highly accurate toner level detection becomes possible.

[0054] As shown in Figure 2(b), an electric field forming capacitance is created between the first electrode 61 and the second electrode 62. Since the second electrode 62 is provided with an electrode protrusion 62a, the edge effect of the electric field lines generated from the second electrode shear surface 62t of the electrode protrusion 62a is taken into account. Due to the edge effect, the capacitance of the detection capacitor C increases compared to the case without the electrode protrusion 62a. As the capacitance increases, the residual detection signal V (SNS(t)) As the amplitude ΔV increases, highly accurate toner level detection becomes possible.

[0055] Furthermore, the sensing capacitor C, i.e., the first electrode 61 and the second electrode 62, are positioned on the side furthest from the free end 63d of the stirring sheet 63b, i.e., the concave side, relative to the second wall surface 59 shown in Figures 1 and 15. In addition, both ends of the stirring sheet 63b (63f, 63g (not shown)) in the longitudinal directions Z1 and Z2 are positioned outside the first side wall 30 and the second side wall 31 inside the sensing capacitor C. That is, the width Wc of the recess 58 in the longitudinal directions Z1 and Z2 (first direction) (the distance between the opposing first side wall 30 and the second side wall 31) is narrower than the width Ws of the stirring sheet 63b in the same direction, and in the same direction, the recess 58 is located in the region between the ends of the stirring sheet 63b (see Figure 15). Therefore, after the free end 63e of the stirring sheet 63b passes through the area of ​​the detection capacitor C while in contact with the first wall surface 57, the free end 63e of the stirring sheet 63b always comes into contact with the second wall surface 59 as it passes through the area of ​​the detection capacitor C. As a result, the free end 63e of the stirring sheet 63b is opened and the toner does not fly around. Consequently, toner can be stably supplied to the detection capacitor C, enabling highly accurate toner level detection. Furthermore, when a slit is provided in the free end 63d of the stirring sheet 63b, a similar effect can be achieved by not providing the slit in the longitudinal direction Z1, Z2, in the area inside the first side wall 30 and the second side wall 31 inside the detection capacitor.

[0056] The first non-opposing shielding wall 69b and the second non-opposing shielding wall 69c are positioned opposite each other via the electrode recess 69a in the nearest direction Y3 and Y4 of the sensing capacitor. Therefore, during injection of the conductive resin, which is the second material in the conductive two-color molding shown in Figure 12(b), leakage of the conductive resin from the first electrode 61 and the second electrode 62 through the gap between the sensing capacitor mold core base 210 and the electrode holder 69 is prevented by a labyrinth effect. By preventing resin leakage, stable electrical insulation between the first electrode 61 and the second electrode 62 can be achieved, thus ensuring mass production of conductive two-color molding. Furthermore, the sensing capacitor non-opposing region L Side In this configuration, the first electrode 61 and the second electrode 62 are not positioned opposite each other in an exposed state, but electric field lines are generated due to the presence of the electrode recess 69a. In addition, the electrode recess 69a is located at the electrode end distance L End Because the following minute gaps can be formed, the strongest electric field can be formed at the detection capacitor C. As a result, the capacitance of the detection capacitor C increases compared to the case without the electrode recess 69a, and the amplitude ΔV increases, similar to the electrode protrusion 62a, enabling highly accurate toner level detection.

[0057] The effects of this embodiment based on capacitance simulation will be explained using Figures 18 and 19(a) and 19(b). Figures 19(a) and 19(b) are comparative examples of the sensing capacitor C for this embodiment. Figure 18 shows the capacitance simulation results for this embodiment and the comparative examples shown in Figures 19(a) and 19(b). The effect of comparative example 1 shown in Figure 19(a) is The second electrode 262 is configured by removing the electrode protrusion 62a from the second electrode 62 of this embodiment. On the other hand, the electrode holder 369 of Comparative Example 2 shown in Figure 19(b) is configured by removing the electrode recess 69a from the electrode holder 269 of this embodiment. As shown in the capacitance simulation results in Figure 18, this embodiment (with electrode protrusion 62a) provides an improvement in capacitance of approximately 4% compared to Comparative Example 1 (without electrode protrusion 62a), and an improvement in capacitance of approximately 9% compared to Comparative Example 2 (without electrode recess 69a).

[0058] The conductive resin structure of the remaining inspection member Z will be explained using Figures 6(a), 6(b), 14(a) to 14(d), 16(a), 16(b), 17(a), and 17(b). Figure 14(a) is a front view showing the structure of the remaining inspection member Z. Figures 14(b) and 14(c) are longitudinal cross-sectional views showing the toner encapsulation structure of Figure 14(a), respectively. Figure 14(d) is a detailed view of the toner encapsulation structure described in Figures 14(b) and 14(c). Figures 16(a), 16(b), 17(a), and 17(b) are explanatory diagrams of the resin flow path and gate arrangement configuration in the conductive resin molding of the detection capacitor C and electrical contacts 64 and 65.

[0059] As shown in Figures 14(a) and 6(a) and 6(b), the residual detection member Z is a capacitive toner residual detection signal detection member composed of an electrode holder 69, a detection capacitor C, and electrical contacts 64 and 65, and is manufactured by conductive two-color molding as shown in Figures 11(a) to 13(b). As shown in Figure 14(c), the first electrical contact 64 and the first electrode 61 are integrally molded via the first electrode channel 610 and the first electrode toner sealing part 611 in the conductive resin molding process shown in Figure 12(b), and are therefore electrically connected. As shown in Figure 14(b), the second electrical contact 65 and the second electrode 62 are also integrally molded via the second electrode channel 620 and the second electrode toner sealing part 621 in the conductive resin molding process shown in Figure 12(b), and are therefore electrically connected. Furthermore, the conductive resin in this embodiment is made of conductive POM consisting of polyacetal (POM) containing approximately 10% carbon black (hereinafter referred to as CB). The insulating resin of the electrode holder 69 is PS+PPE resin, but is not limited to this.

[0060] As shown in Figure 14(d), the second electrode channel 620 and the second electrode toner sealing portion 621 are integrally molded from conductive resin and integrally bonded to the electrode holder 69. The first electrode channel 610 and the first electrode toner sealing portion 611 have a similar configuration, so here we will describe the toner sealing configuration using the second electrode toner sealing portion 621 and the second electrode channel 620.

[0061] The second electrode toner sealing portion 621 is composed of second electrode toner sealing protrusions 621a and 621d and second electrode toner sealing recesses 621b and 621c. The second electrode toner sealing protrusions 621a and 621d are positioned in the direction X4 perpendicular to the nearest detection capacitor, which is outward in the longitudinal directions Z1 and Z2 relative to the second electrode toner sealing recesses 621b and 621c and on the side facing the toner storage portion 60. In other words, the second electrode toner sealing recesses 621b and 621c are positioned inward in the longitudinal directions Z1 and Z2 relative to the second electrode toner sealing protrusions 621a and 621d and on the side facing the nearest detection capacitor, which is away from the toner storage portion 60.

[0062] The electrical contacts 64 and 65 and the sensing capacitor C are molded in the manner shown in Figures 16(a), 16(b), 17(a), and 17(b). First, as shown in Figure 16(a), the conductive resin injected into the runner 601 from an injection molding machine (not shown) at a predetermined injection speed branches into a first electrode gate section 612 and a second electrode gate section 622. The conductive resin flowing through the first electrode gate section 612 begins to flow into the first electrode flow path 610 via the first gate connection section 613. Similarly, the conductive resin flowing through the second electrode gate section 622 begins to flow into the second electrode flow path 620 via the second gate connection section 623. The first gate connection section 613 is an inlet for conductive resin provided in the middle of the first electrode flow path 610, which serves as a conductive path connecting the first electrode 61 and the first electrical contact 64. The second gate connection portion 623 connects the second electrode 62 and the second electrical contact 65. This is an inlet for conductive resin provided in the middle of the first electrode flow path 610, which acts as a path. Next, as shown in Figure 16(b), the first electrode flow path 610 and the second electrode flow path 620 branch out in the longitudinal direction Z1 toward the electrical contacts 64 and 65, and in the longitudinal direction Z2 toward the sensing capacitor C, respectively. Furthermore, as shown in Figure 17(a), the conductive resin on the longitudinal direction Z2 side flows beyond the first electrode toner sealing part 611 and the second electrode toner sealing part 621 to a part of the sensing capacitor C. At this stage, the conductive resin on the longitudinal direction Z1 side flows to the first electrical contact molding distance L 64 and second electrical contact forming distance L 65is filled by that amount, and the filling of electrical contacts 64 and 65 is completed. In this case, the resin filling volumes from each gate (each gate connection portion 613, 623) to the electrical contacts 64 and 65 are respectively defined as the first electrical contact molding volume V 64 and the second electrical contact molding volume V 65 . Further, as shown in Fig. 17(a), the conductive resin injected into the runner 601 at a predetermined injection speed from an injection molding machine (not shown) does not branch in the longitudinal direction Z1, which is the direction toward the electrical contacts 64 and 65 in the first electrode flow path 610 and the second electrode flow path 620, and is filled only toward the longitudinal direction Z2, which is the direction toward the detection capacitor C. Therefore, according to the law of flow rate, compared with the flow velocity before forming electrical contacts v1, which is the flow velocity before molding the electrical contacts 64 and 65 shown in Figs. 16(a) and 16(b), the flow velocity after forming electrical contacts v2, which is the flow velocity from after molding the electrical contacts 64 and 65 to the completion of molding the detection capacitor C as shown in Fig. 17(a), is higher than the flow velocity before forming electrical contacts v1. Finally, as shown in Fig. 17(b), when the molding of the detection capacitor C is completed, the conductive resin on the longitudinal direction Z2 side is filled by the amount corresponding to the first electrode molding distance L61 and the second electrode molding distance L 62 respectively. In this case, the resin filling volumes from each gate to the detection capacitor C are respectively defined as the first electrode molding volume V 61 and the second electrode molding volume V 62 . In order to satisfy the relationship of flow velocity before forming electrical contacts v1 < flow velocity after forming electrical contacts v2, the first electrode gate portion 612 and the second electrode gate portion 622 are respectively arranged so as to satisfy the relationship of the following formula. First electrical contact molding volume V 64 < First electrode molding volume V 61 Second electrical contact molding volume V 65 < Second electrode molding volume V 62

[0063] In the residual inspection member Z of this embodiment, during conductive two-color molding, the second electrode toner sealing protrusions 621a and 621d are tightened inward in the longitudinal directions Z1 and Z2 of the second electrode toner sealing recesses 621b and 621c by molding shrinkage, thereby sealing the toner in the toner storage section 60. Here, if the material of the developing frame 52 shown in Figure 1 is made of PS resin, compatibility with the electrode holder 69 is obtained. Therefore, it becomes possible to join them by methods such as ultrasonic welding or heat crimping without using other materials such as adhesives or tapes, which is more preferable in terms of ensuring strength, reducing costs, and reducing environmental impact. Furthermore, since the first electrical contact 64, the first electrode 61, the first electrode flow path 610, and the first electrode toner sealing section 611 are all integrated by conductive two-color molding, there is no contact resistance between these elements, and only internal resistance exists. Similarly, there is no contact resistance between the elements of the second electrical contact 65, the second electrode 62, the second electrode flow path 620, and the second electrode toner sealing section 621, and only internal resistance exists. Therefore, compared to a configuration where electrical contacts 64 and 65 and detection capacitor C are provided as separate components and electrically connected to each other, the contact resistance between the components is eliminated, thus reducing the residual detection signal V (SNS(t)) This makes it possible to suppress the parasitic resistance R, which is a factor in attenuation.

[0064] Furthermore, in the residual inspection member Z of this embodiment, the relationship v1 < v2 before electrical contact formation is satisfied, so the injection speed of the conductive resin at the electrical contacts 64 and 65 can be kept low. By keeping the injection speed of the conductive resin low, shear fracture of the CB contained in the conductive resin is suppressed on the surface of the electrical contacts 64 and 65 formed by the skin layer with the mold, so that the conductive effect of the CB is maintained even after molding. As a result, the increase in surface resistance of the electrical contacts 64 and 65 is prevented, and the contact resistance with the electrical contact springs 90 and 91 shown in Figures 8(a), 8(b), and 9(a) to 9(c) is suppressed, thus reducing the residual inspection signal V (SNS(t)) This makes it possible to suppress the parasitic resistance R, which is a damping factor. On the other hand, the surface resistance of the sensing capacitor C, which is filled with a flow velocity v2 after the formation of the electrical contacts, is lowered by the flow velocity v1 before the formation of the electrical contacts. Due to the relationship between the flow velocity v2 after electrical contact formation, the surface resistance of electrical contacts 64 and 65 becomes higher than that of electrical contacts 64 and 65 due to shear failure of CB. However, since the sensing capacitor C is configured to detect the change in capacitance due to the inflow and outflow of toner in the toner storage section 60 as capacitive reactance, the increase in surface resistance in sensing capacitor C does not affect the residual detection signal V (SNS(t)) This does not contribute to attenuation. For this reason, in an integrated configuration of conductive resin electrical contacts 64, 65 and sensing capacitor C, it is preferable to keep the injection speed of the conductive resin at the electrical contacts 64, 65 lower than that of other filling locations in order to reduce the surface contact resistance, which is a part of the parasitic resistance R, as much as possible.

[0065] The disclosure of embodiments of the present invention includes the following configurations. (Composition 1) A developing device, A frame having a compartment for containing the developer, Inside the housing, a first electrode portion and a second electrode portion are exposed from the frame and arranged to face each other, The stirring member comprises a rotating shaft that rotates about a rotation axis extending in a first direction, and a sheet whose end in a second direction perpendicular to the first direction is fixed to the rotating shaft and is a fixed end, and whose end opposite to the fixed end in the second direction is a free end, and whose length from the fixed end to the free end is a length that allows it to contact the inner wall of the frame that constitutes the housing, A portion of the inner wall of the frame has a recess that is recessed in the direction away from the axis of rotation in the second direction, The first electrode portion and the second electrode portion are provided in the recess, A developing apparatus characterized in that the width of the recess in the first direction is narrower than the width of the sheet in the first direction, and the recess in the first direction is located in the region between both ends of the sheet. (Configuration 2) The first electrode portion is provided on the upstream side of the recess in the rotational direction of the rotational shaft, The developing apparatus according to configuration 1, characterized in that the second electrode portion is provided downstream of the recess in the rotational direction. (Composition 3) The first electrode has a shape that, when viewed in the first direction, moves away from the axis of rotation as it moves in the direction of rotation, The developing apparatus according to configuration 1 or 2, characterized in that the second electrode has a shape that, when viewed in the first direction, approaches the axis of rotation as it moves toward the direction of rotation. (Composition 4) The recess includes a first side wall facing the first direction and a second side wall facing the first direction and facing the first side wall in the first direction. The developing apparatus according to any one of configurations 1 to 3, characterized in that the first electrode and the second electrode are provided between the first side wall and the second side wall, respectively, with the first direction being the longitudinal direction. (Composition 5) The aforementioned frame body is A developing chamber that communicates with the storage section through an opening, A developing roller placed in the developing chamber, It has, The inner wall of the frame is The first wall surface provided with the aforementioned opening, A second wall surface, which is provided with the recess, is connected downstream of the first wall surface in the rotational direction of the rotational shaft, Includes, The developing apparatus according to any one of configurations 1 to 4, characterized in that the length of the sheet from the fixed end to the free end is long enough to contact at least the first wall surface and the second wall surface. (Composition 6) The frame has insulating properties, A first conductive member having a first electrode portion and a first electrical contact portion connected to the first electrode portion and exposed to the outside of the housing portion, A second conductive member having the second electrode portion and a second electrical contact portion connected to the second electrode portion and exposed to the outside of the housing portion, It has, The first conductive member and the second conductive member are integrally molded with the frame by injecting conductive resin into the frame. A developing apparatus according to any one of the configurations 1 to 5, characterized by the features described above. (Composition 7) The developing apparatus according to configuration 6, characterized in that the frame body includes a first part that rotatably supports the rotation shaft, and a second part that is configured separately from the first part, is provided with the recess, and has the first conductive member and the second conductive member integrally molded with it. [Explanation of Symbols]

[0066] C...Detection capacitor, 50...Developing unit, 52...Developing frame, 52a...Detection capacitor connection wall, 52b...Detection capacitor connection wall, 52c...Detection capacitor connection first side wall, 52d...Detection capacitor connection second side wall, 60...Toner storage section, 61...First electrode, 61b...Facing surface of the first electrode tip, 61e...First electrode end, 61s...First electrode start end, 61f...First electrode exposed portion, 62...Second electrode, 62a...Electrode protrusion, 62b...Facing surface of the second electrode tip, 62e...Second electrode end, 62s...Second electrode start end, 62t...Second electrode Shear section, 63... Stirring member, 63a... Stirring shaft, 63b... Stirring sheet, 63c... Center of the rotating shaft of the stirring member, 64... First electrical contact, 64a... First end of the first electrical contact, 64b... Second end of the first electrical contact, 64c... Center of the first electrical contact, 64t... Contact portion of the first electrical contact, 65... Second electrical contact, 65a... First end of the second electrical contact, 65b... Second end of the second electrical contact, 65c... Center of the second electrical contact, 65t... Contact portion of the second electrical contact, 69... Electrode holder, 69a... Electrode recess, 69b... First non-opposing shielding wall, 69c... Second non-opposing shielding wall

Claims

1. A developing device, A frame having a compartment for containing the developer, Inside the housing, a first electrode portion and a second electrode portion are exposed from the frame and arranged to face each other, The stirring member comprises a rotating shaft that rotates about a rotation axis extending in a first direction, and a sheet whose end in a second direction perpendicular to the first direction is fixed to the rotating shaft and is a fixed end, and whose end opposite to the fixed end in the second direction is a free end, and whose length from the fixed end to the free end is long enough to contact the inner wall of the frame that constitutes the housing, A portion of the inner wall of the frame has a recess that is recessed in the direction away from the axis of rotation in the second direction, The first electrode portion and the second electrode portion are provided in the recess, A developing apparatus characterized in that the width of the recess in the first direction is narrower than the width of the sheet in the first direction, and the recess in the first direction is located in the region between both ends of the sheet.

2. The first electrode portion is provided on the upstream side of the recess in the rotational direction of the rotational shaft, The developing apparatus according to claim 1, characterized in that the second electrode portion is provided downstream of the recess in the rotational direction.

3. The first electrode has a shape that, when viewed in the first direction, moves away from the axis of rotation as it moves in the direction of rotation, The developing apparatus according to claim 2, characterized in that the second electrode has a shape that, when viewed in the first direction, approaches the axis of rotation as it moves in the direction of rotation.

4. The recess includes a first side wall facing the first direction and a second side wall facing the first direction and facing the first side wall in the first direction. The developing apparatus according to claim 3, characterized in that the first electrode and the second electrode are provided between the first side wall and the second side wall, respectively, with the first direction being the longitudinal direction.

5. The aforementioned frame body is A developing chamber that communicates with the storage section through an opening, A developing roller placed in the developing chamber, It has, The inner wall of the frame is The first wall surface provided with the aforementioned opening, A second wall surface, which is provided with the recess, is connected downstream of the first wall surface in the rotational direction of the rotational shaft, Includes, The developing apparatus according to claim 1, characterized in that the length of the sheet from the fixed end to the free end is long enough to contact at least the first wall surface and the second wall surface.

6. The frame has insulating properties, A first conductive member having a first electrode portion and a first electrical contact portion connected to the first electrode portion and exposed to the outside of the housing portion, A second conductive member having the second electrode portion and a second electrical contact portion connected to the second electrode portion and exposed to the outside of the housing portion, It has, The first conductive member and the second conductive member are integrally molded with the frame by injecting conductive resin into the frame. The developing apparatus according to feature 1.

7. The developing apparatus according to claim 6, characterized in that the frame body includes a first portion that rotatably supports the rotation shaft, and a second portion that is configured separately from the first portion, is provided with the recess, and has the first conductive member and the second conductive member integrally molded with it.

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