Cartridge and image forming apparatus

Abstract

To provide a new configuration for detecting the amount of developer in a container by using light.SOLUTION: A cartridge comprises a container, light guide means that includes an incident part and an emission part, and a cover member that covers a part of the light guide means. The incident part has a columnar shape centered on a center line. When a direction along the center line, directed from a side of an outer surface to a side of an inner surface of the cover member is defined as a first direction, the cover member has a recess in which a part of the outer surface is depressed between the incident part and the emission part. A first end of a bottom face of the recess on the side of the incident part is located on the downstream side in the first direction with respect to a second end of the bottom face on the side of the emission part in the second direction, and between the first end and the second end, the bottom face is bent to be concave on the downstream side in the first direction with respect to a virtual straight line connecting the first end and the second end.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present invention relates to a cartridge mounted to an apparatus main body of an image forming apparatus, and an image forming apparatus that forms an image on a recording material.

Background Art

[0002] In an electrophotographic image forming apparatus, a cartridge is used in which an image carrier such as a photosensitive drum and a process means such as a developing roller that acts on the image carrier are integrated to be detachable from the apparatus main body of the image forming apparatus. Patent Documents 1 and 2 describe a configuration in which a light guide is attached to a developer container of a process cartridge, and guides the light emitted from a light-emitting element of the apparatus main body such that the light reaches a light-receiving element of the apparatus main body via the internal space of the developer container, thereby enabling detection of the amount of developer in the developer container.

Prior Art Literature

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0004] An object of the present invention is to provide a new configuration for detecting the amount of developer in a container using light.

Means for Solving the Problem

[0005] One aspect of the present invention is a cartridge comprising: a container configured to contain a developer; an incident portion configured to receive light from outside the cartridge; and an outgoing portion configured to emit the light that has entered the container through the incident portion to the outside of the cartridge; and a cover member having a first opening through which the incident surface of the incident portion is exposed and a second opening through which the outgoing surface of the outgoing portion is exposed, and covering a part of the light guide means, wherein the incident portion has a columnar shape centered on a central line, the direction of the central line from the outer surface to the inner surface of the cover member is defined as the first direction, and the incident portion and the outgoing portion are aligned in a direction intersecting the first direction. When the direction is defined as the second direction, and the direction intersecting both the first and second directions is defined as the third direction, the cover member is characterized in that, in a cross section perpendicular to the third direction, a part of the outer surface of the cover member has a recess that is recessed on the downstream side of the first direction between the inlet and outlet portions in the second direction, the first end of the bottom surface of the recess on the inlet portion side in the second direction is located downstream of the first direction than the second end of the bottom surface on the outlet portion side in the second direction, and the bottom surface is curved between the first and second ends such that it is recessed on the downstream side of the first direction with respect to a virtual straight line connecting the first and second ends.

[0006] Another aspect of the present invention is a cartridge comprising: a container configured to contain a developer; an incident portion configured to receive light from outside the cartridge; and an outgoing portion configured to emit the light that has entered the container through the incident portion to the outside of the cartridge; and a cover member having a first opening through which the incident surface of the incident portion is exposed, and a second opening through which the outgoing surface of the outgoing portion is exposed, and covering a part of the light guide means, wherein the direction of the optical axis of the incident portion is defined as the direction from the outer surface to the inner surface of the cover member, and the direction intersecting the first direction, in which the incident portion and the outgoing portion are aligned, is defined as the second direction. When the third direction is defined as the direction that intersects both the first and second directions, the cover member is characterized in that, in a cross section perpendicular to the third direction, a part of the outer surface of the cover member has a recess that is recessed on the downstream side of the first direction between the inlet and outlet portions in the second direction, the first end of the bottom surface of the recess on the inlet portion side in the second direction is located downstream of the first direction than the second end of the bottom surface on the outlet portion side in the second direction, and the bottom surface is curved between the first and second ends such that it is recessed on the downstream side of the first direction with respect to a virtual straight line connecting the first and second ends. [Effects of the Invention]

[0009] According to the present invention, a novel configuration can be provided for detecting the amount of developer in a container using light. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic diagram of a printer according to one embodiment. [Figure 2] A front view of a process cartridge according to one embodiment. [Figure 3] A cross-sectional view of a process cartridge according to one embodiment. [Figure 4] A cross-sectional view of a process cartridge according to one embodiment. [Figure 5]A cross-sectional view of a process cartridge according to one embodiment. [Figure 6] A front view of a toner cartridge according to one embodiment. [Figure 7] A cross-sectional view of a toner cartridge according to one embodiment. [Figure 8] A cross-sectional view of a toner cartridge according to one embodiment. [Figure 9] Exploded view (a, b) of a process cartridge according to one embodiment. [Figure 10] Side views (a, b) illustrating the mounting of a process cartridge and a toner cartridge to the main body of the device according to one embodiment. [Figure 11] Perspective views (a, b) illustrating the mounting of a process cartridge and a toner cartridge to the main body of the device according to one embodiment. [Figure 12] Schematic diagrams (a-c) illustrating the mounting of a process cartridge and a toner cartridge to the main body of the device according to one embodiment. [Figure 13] Exploded view (a, b) of a toner cartridge according to one embodiment. [Figure 14] A perspective view (a) and an enlarged view (b) showing a part of a developing unit according to one embodiment. [Figure 15] An exploded view showing some components of a developing unit according to one embodiment removed. [Figure 16] A top view showing a process cartridge and part of the printer body according to one embodiment. [Figure 17] Figure 16 shows a cross-sectional view (a) of the process cartridge and a portion of the printer body along the line z1-z1, and a magnified view (b) of a portion thereof. [Figure 18] A diagram showing the cross-sectional shape of a light guide cover according to one embodiment. [Figure 19] Figures (a, b) show a configuration for positioning components when a process cartridge is installed according to one embodiment. [Figure 20] A side view showing the development contact state (a) and development separation state (b) of a process cartridge according to one embodiment. [Figure 21] A side view of a process cartridge according to an embodiment. [Figure 22] A schematic diagram showing an element arrangement (a) of a process cartridge according to an embodiment and an element arrangement (b) in a comparative example. [Figure 23] A perspective view showing a drive train of a process cartridge according to an embodiment. Description of Embodiments

[0011] Hereinafter, an apparatus according to the present disclosure will be described with reference to the drawings.

[0012] In the following description, an "image forming apparatus" is an apparatus that forms an image on a recording material (recording medium) using toner as a developer, and includes single-function printers, copiers, and multifunction peripherals. Sheets used as recording media include paper such as plain paper and cardboard, plastic films such as overhead projector sheets, specially shaped sheets such as envelopes and index paper, and cloth.

[0013] <Overall Configuration of Printer> Figure 1 is a schematic diagram showing a cross-sectional configuration of a laser beam printer (hereinafter referred to as printer 1) serving as an image forming apparatus according to an embodiment. The printer 1 includes a printer main body A, a process cartridge B, and a toner cartridge C.

[0014] The printer main body A includes a sheet feeding unit 103, a transfer roller 104, a fixing device 105, and a laser scanner 101. The process cartridge B is detachably provided to the printer main body A. A process cartridge is obtained by forming an image bearing member and a processing means acting on the image bearing member into a cartridge, and is detachably mounted to the image forming apparatus main body. The toner cartridge C accommodates toner as a developer and is detachably mounted to the image forming apparatus main body. The printer main body A can be referred to as a portion obtained by removing the process cartridge B and the toner cartridge C from the printer 1.

[0015] Process cartridge B will be explained using Figures 2, 3, 4, and 5. Figure 2 is a front view of process cartridge B (a view of process cartridge B from the left side in Figure 1). Figure 3 is a cross-sectional view of process cartridge B (cross-section aa in Figure 2). Figure 4 is a cross-sectional view showing the second waste toner transport path 10c of process cartridge B (cross-section bb in Figure 2). Figure 5 is a cross-sectional view showing the replenishment port of process cartridge B (cross-section cc in Figure 2).

[0016] In the following, the vertical direction (vertically upward) when the printer body A is installed with process cartridge B and toner cartridge C and the printer body A is placed on a horizontal surface is indicated by arrow Y in Figure 6, etc. The longitudinal direction of process cartridge B (direction of the rotation axis of the photosensitive drum 11) is indicated by arrow Z. Furthermore, the horizontal direction perpendicular to both the longitudinal direction (arrow Z) and the vertical direction (arrow Y) of process cartridge B is indicated by arrow X. Note that the arrangement and shape of the elements of process cartridge B and toner cartridge C will be explained based on the state in which process cartridge B and toner cartridge C are installed in the printer body A.

[0017] The side of the process cartridge B in the longitudinal direction that receives the driving force primarily from the printer body A is called the drive side (left side in Figure 2), and the opposite side is called the non-drive side (right side in Figure 2). The arrow Z in the figure represents the direction from the non-drive side to the drive side. The in-plane direction of the virtual plane perpendicular to the longitudinal direction (arrow Z) is collectively referred to as the short side of the process cartridge B.

[0018] As shown in Figures 2, 3, and 4, process cartridge B consists of a cleaning unit 10 as a first unit (photoreceptor unit) and a developing unit 15 as a second unit. The cleaning unit 10 includes a photosensitive drum 11 as an image carrier. The developing unit 15 includes a developing means for carrying toner as a developer or a developing roller 16 as a developer carrier.

[0019] The cleaning unit 10 includes a photosensitive drum 11 (photosensitive drum assembly), a cleaning blade 17 as a cleaning member for the photosensitive drum 11, and a charging roller 12 as a charging member. The cleaning unit 10 also includes a charging roller cleaner 14 as a cleaning member for the charging roller 12, a primary waste toner storage section 10a, a first waste toner transport path 10b, and a second waste toner transport path 10c.

[0020] The photosensitive drum 11 is formed by creating a photosensitive layer on the outer circumference of a cylindrical (drum-shaped) substrate using an organic photoreceptor or the like. The charging roller 12 is positioned to contact the outer surface of the photosensitive drum 11. The charging roller 12 charges the photosensitive drum 11 by applying a voltage from a high-voltage substrate provided in the printer body A. The charging roller 12 also rotates in a manner driven by the photosensitive drum 11 (that is, it rotates in accordance with the rotation of the photosensitive drum 11).

[0021] The cleaning blade 17 is an elastic component positioned to contact the outer surface of the photosensitive drum 11. The cleaning blade 17 removes waste toner from the photosensitive drum 11 by elastically contacting the photosensitive drum 11 with its tip. The waste toner removed by the cleaning blade 17 is transported from the waste toner primary storage section 10a (described later) to the toner cartridge C via the first waste toner transport path 10b and the second waste toner transport path 10c.

[0022] As shown in Figure 5, the developing unit 15 includes a developing chamber 151 in which developing rollers 16 are placed, a developer storage chamber 152 for supplying toner to the developing chamber 151, and a receiving chamber 153 for receiving toner supplied from the toner cartridge C. The developing chamber 151 and the developer storage chamber 152 are spaces formed inside the developing frame 415, which serves as a container.

[0023] The developing roller 16 supplies toner to the developing area of ​​the photosensitive drum 11 (the area of ​​the photosensitive drum 11 facing the developing roller 16). In the developing area, the developing roller 16 develops the electrostatic latent image formed on the photosensitive drum 11 using toner. In addition, a supply roller 13 that supplies toner to the developing roller 16 is located in the developing chamber 151.

[0024] The developing blade 18 contacts the circumferential surface of the developing roller 16 and regulates the amount (thickness) of toner that adheres to the circumferential surface of the developing roller 16. In addition, the developing blade 18 frictionally charges the toner particles by rubbing against the toner adhering to the circumferential surface of the developing roller 16, thereby imparting an electric charge to the toner particles.

[0025] An agitator 154 is placed in the developer storage chamber 152. The toner stored in the developer storage chamber 152 is agitated by the rotation of the agitator 154 and sent to the developing chamber 151, where it is supplied to the developing roller 16. The agitator 154 has a shaft portion extending in the longitudinal direction and a flexible, sheet-like agitator portion protruding metrically from the shaft portion. A supply roller 13 can be placed in the developing chamber 151 to supply the toner in the developing chamber 151 to the developing roller 16.

[0026] The amount of toner in the developer storage chamber 152 is detected by a remaining amount detection means, which will be described later. Based on the detection signal from the remaining amount detection means, the control unit of the printer body A performs the operation of supplying toner from toner cartridge C to process cartridge B when the amount of toner in the developer storage chamber 152 falls below a certain level.

[0027] The receiving chamber 153 is configured to receive toner from the toner cartridge C via a passage provided in the cleaning unit 10. Specifically, the stay 21, which constitutes part of the cleaning unit 10, is provided with a replenishment port 21c for receiving toner from the toner cartridge C and a transfer port 21d for transferring toner to the receiving chamber 153 of the developing unit 15.

[0028] Next, the operation of printer 1 will be explained using Figure 1. Printer 1 starts image formation when it receives image information from an external device, for example. When image formation starts, the photosensitive drum 11 is rotated by the drive source of the printer body A, and the surface of the photosensitive drum 11 is uniformly charged to a predetermined potential by the charging roller 12. Next, the laser scanner 101 exposes the charged surface of the photosensitive drum 11 based on the image information. As a result, the charge in the exposed area is removed, and an electrostatic latent image is formed on the surface of the photosensitive drum 11. Toner is supplied to this electrostatic latent image from the developing roller 16, and the electrostatic latent image is developed into a toner image. The toner image carried on the photosensitive drum 11 is transported to the transfer section, which is the nip section between the photosensitive drum 11 and the transfer roller 104.

[0029] Meanwhile, in parallel with the creation of the toner image, the sheet feeding unit 103 transports the sheets S one by one. Specifically, the feeding roller 103a rotates and feeds the sheets S loaded on the feeding tray one by one. Then, in time with the arrival of the toner image at the transfer unit, the sheets S are transported to the transfer unit. As the sheets pass through the transfer unit, the toner image is transferred from the photosensitive drum 11 to the sheets S by the transfer roller 104, which is supplied with a transfer voltage from a high-voltage substrate. Any toner remaining on the surface of the photosensitive drum 11 that was not transferred to the sheets S in the transfer unit (waste toner) is removed from the surface of the photosensitive drum 11 by the cleaning blade 17.

[0030] The sheet S onto which the toner image has been transferred is transported to the fuser unit 105. The fuser unit 105 uses a heat-fixing method, and while transporting the sheet S by clamping it between the nip portions of a pair of rotating bodies, it heats and pressurizes the toner image on the sheet S. This results in an image fixed to the sheet S. In the case of single-sided printing, the sheet S that has passed through the fuser unit 105 is discharged to the outside of the printer body A by a pair of discharge rollers which serve as discharge means, and is loaded onto an discharge tray 106 provided on the top surface of the printer body A. In the case of double-sided printing, the sheet S, on which an image has been formed on the first side by passing through the transfer unit and fuser unit 105, is inverted by a pair of discharge rollers which also serve as inversion means, and is transported back towards the transfer unit via a re-transport path. Then, the sheet S, on which an image has been formed on the second side by passing through the transfer unit and fuser unit 105 a second time, is discharged to the outside of the printer body A by a pair of discharge rollers and is loaded onto an discharge tray 106 provided on the top surface of the printer body A.

[0031] <Processing Cartridge> The configuration of process cartridge B in this embodiment will be described in detail using Figures 3, 9(a, b), and 10(a, b). Figure 9(a, b) is an exploded perspective view of process cartridge B. Figure 10(a) is a side view showing process cartridge B in contact with development. Figure 10(b) is a side view showing process cartridge B separated from development.

[0032] As shown in Figure 9(a, b), bearing members 4 and 5 are positioned at the ends of the developing unit 15 in the axial direction of the developing roller 16. The developing unit 15 is coupled to the cleaning unit 10 so that it can pivot (rotate) around a pivot axis 8 defined by a straight line passing through the support shafts 8a and 8b, which will be described below. The pivot axis 8 is substantially parallel to the rotation axis A11 of the photosensitive drum 11.

[0033] The frame of the cleaning unit 10 consists of a main frame 20, a stay 21, and a side cover 7. The main frame 20 supports the cleaning blade 17, the charging roller 12, and the charging roller cleaner 14. The photosensitive drum 11 is rotatably supported on one side by a drum pin 22 attached to the main frame 20, and on the other side by a photosensitive drum support part 7b provided on the side cover 7.

[0034] The configuration in which the developing unit 15 is supported by the cleaning unit 10 will be described in detail. As shown in Figure 9(a), the cylindrical shape 5a provided in the bearing member 5 is supported by the cylindrical hole shape 7a provided in the side cover 7 of the cleaning unit 10. The support shaft 8a is defined by the common axis between the cylindrical hole shape 7a of the side cover 7 and the cylindrical shape 5a of the bearing member 5. Also, as shown in Figure 9(b), the pin 6 is inserted so as to straddle the cylindrical hole shape 20a of the main frame 20 of the cleaning unit 10 and the cylindrical hole shape 4a of the bearing member 4. The support shaft 8b is defined by the common axis between the pin 6 and the cylindrical hole shape 4a of the bearing member 4. The support shafts 8a and 8b are substantially located on the same axis, and as described above, the oscillation axis 8 is defined by a straight line including the support shafts 8a and 8b.

[0035] The protruding portion 5b of the developing unit 15, which will be described later, is part of the bearing member 5. In other words, the portion (cylindrical shape 5a) to which the developing unit 15 (second unit) is pivotably supported by the cleaning unit 10 (first unit) and the protruding portion 5b, which is the part to be pressed, are provided on the same member (bearing member 5). This configuration improves the positional accuracy between the protruding portion 5b and the cylindrical shape 5a, and allows the developing roller 16 to move with high precision due to the pressing of the protruding portion 5b. Alternatively, a cylindrical shape may be provided in the side cover 7 instead of the cylindrical hole shape 7a, and a cylindrical hole shape that fits into this cylindrical shape may be provided in the bearing member 5.

[0036] The developing unit 15 is movable around the pivot axis 8 between a contact position where the developing roller 16 is in contact with the photosensitive drum 11 and a separation position where the developing roller 16 is separated from the photosensitive drum 11. Hereinafter, the state of process cartridge B when the developing unit 15 is in the contact position will be referred to as the "developing contact state," and the state of process cartridge B when the developing unit 15 is in the separation position will be referred to as the "developing separation state."

[0037] Process cartridge B has pressure springs 19a and 19b as biasing means for biasing the developing unit 15. The pressure springs 19a and 19b are elastic members that connect the developing unit 15 and the cleaning unit 10, and in the illustrated configuration, tension springs are used. The developing unit 15 is biased toward the contact position by the pressure springs 19a and 19b.

[0038] Furthermore, the printer body A is equipped with a separation mechanism 100, described later, as an actuator for moving the developing unit 15 between a contact position and a separated position. The separation lever 100a, which acts as a pressing member, is movable between a position that holds the developing unit 15 in the contact position and a position that allows the developing unit 15 to move from the contact position to the separated position. In other words, the separation mechanism 100 can move the developing unit 15 from the contact position to the separated position against the biasing force of the pressure springs 19a and 19b.

[0039] The movement of the developing unit 15 between the contact position and the separation position will be explained using Figures 10(a, b) and 20(a, b). Figure 10(a) is a side view showing the process cartridge B in the developing contact state, and Figure 20(a) is a detailed view thereof. Figure 10(b) is a side view showing the process cartridge B in the developing separation state, and Figure 20(b) is a detailed view thereof. Note that the side cover 7 of the cleaning unit 10 is omitted in Figures 10(a, b) in order to show the separation mechanism 100 of the printer body A.

[0040] As shown in Figures 10(a, b) and 20(a, b), the bearing member 5 of the developing unit 15 is provided with a protrusion 5b. The protrusion 5b is the part (pressed part) that is pressed by the separation lever 100a of the separation mechanism 100.

[0041] The separation mechanism 100 of the printer body A includes a separation lever 100a as a pressing member, a separation cam 100b that moves the separation lever 100a, and a motor 100c that rotationally drives the separation cam 100b. The separation lever 100a is rotatably mounted around an axis 100a1 that is substantially parallel to the rotation axis of the developing roller 16. Each time the motor 100c rotates the separation cam 100b by a predetermined amount (e.g., 180 degrees) based on a command from the control unit of the printer body A, the position of the separation lever 100a switches between a position that presses against the protrusion 5b and a position that is retracted from the protrusion 5b.

[0042] As shown in Figures 10(a) and 20(a), when the separation lever 100a is retracted from the protrusion 5b, the biasing force of the pressure springs 19a and 19b holds the developing unit 15 in contact position and the developing roller 16 contacts the photosensitive drum 11. In this state, the developing roller 16 can develop the electrostatic latent image formed on the surface of the photosensitive drum 11. In other words, the developing contact state is a state in which image formation can be performed using the process cartridge B. Furthermore, the contact position of the developing unit 15 is the position of the developing unit 15 during image formation, or in other words, the position in which the developing unit 15 can properly perform the developing process with the developer carrier.

[0043] As shown in Figures 10(b) and 20(b), the separation lever 100a is pressed by the separation cam 100b and rotates, contacting the projection 5b, and can rotate the developing unit 15 in the direction of arrow R2 against the biasing force of the pressure springs 19a and 19b. That is, the force that the projection 5b receives from the separation lever 100a causes the developing unit 15 to rotate in the direction from the contact position to the separation position (direction R2) with the pivot axis 8 as the pivot point. As a result, the developing unit 15 moves to the separation position, and the developing roller 16 separates from the photosensitive drum 11.

[0044] The developing-away state is the state when process cartridge B is not performing image formation operations (non-image formation). The developing unit 15's separated position is the position of the developing unit 15 when it is not forming an image, in other words, the position where the developer carrier is farther from the image carrier than the position in which the developing unit 15 can perform the developing process with the developer carrier. The control unit of the printer body A controls the motor 100c to put process cartridge B into the developing-away state during periods when image formation is not being performed (non-image formation), such as after the completion of an image formation job and before the next job has been submitted.

[0045] When the separation lever 100a returns to its original position (Figures 10(a) and 20(a)), the separation lever 100a moves away from the protrusion 5b. As a result, the biasing force of the pressure springs 19a and 19b causes the developing unit 15 to move from the separated position to the contact position. That is, as shown in Figure 10(a), the developing roller 16 and the photosensitive drum 11 come into contact again.

[0046] Thus, the separation mechanism 100 allows the process cartridge B to be switched between a developing-contact state and a developing-separated state. For this reason, for example, by keeping the process cartridge B in the developing-separated state when not forming an image, it is possible to suppress the deterioration of the toner and the photosensitive drum 11, and to suppress unnecessary toner consumption when not forming an image.

[0047] <Toner Cartridge Overview> The toner cartridge C will be explained using Figures 6, 7, 8, and 13(a, b). Figure 6 is a front view of the toner cartridge C (viewed from the left in Figure 1). Figure 7 is a cross-sectional view of the toner supply section 30 of the toner cartridge C (section aa in Figure 6). Figure 8 is a cross-sectional view of the waste toner collection section 40 of the toner cartridge C (section bb in Figure 6). Figure 13(a, b) is an exploded view of the toner cartridge C.

[0048] As shown in Figure 6, the toner cartridge C has an elongated shape that extends in a predetermined longitudinal direction. In Figure 6, etc., the direction from one end to the other of the toner cartridge C along its longitudinal direction is indicated by arrow Z. The longitudinal direction of the toner cartridge C is substantially parallel to the direction of the rotation axis of the photosensitive drum 11 and the rotation axis of the developing roller 16 when the toner cartridge C and process cartridge B are installed in the printer body A. That is, the longitudinal direction of the toner cartridge C is substantially parallel to the longitudinal direction of the process cartridge B.

[0049] The directions of the arrows X, Y, and Z shown in Figure 6, etc., are the same as those used in the explanation of process cartridge B (Figure 2, etc.).

[0050] The side of the toner cartridge C in the longitudinal direction that receives the driving force mainly from the printer body A is called the drive side (left side in Figure 6), and the opposite side is called the non-drive side (right side in Figure 6). In this embodiment, the drive side is the side on which the toner supply unit 30 is located relative to the waste toner collection unit 40 described below, and the non-drive side is the side on which the waste toner collection unit 40 is located relative to the toner supply unit 30. The in-plane direction of a virtual plane perpendicular to the longitudinal direction (arrow Z) is collectively referred to as the short direction of the toner cartridge C.

[0051] <Toner Supply Department> As shown in Figure 6, the toner cartridge C includes a toner supply unit 30 that supplies toner to the process cartridge B, a waste toner collection unit 40 that collects waste toner from the process cartridge B, and a pump unit 37.

[0052] As shown in Figures 6, 7, and 13(a, b), the toner supply unit 30 includes a toner storage unit 30a for storing toner. The toner storage unit 30a is formed by a supply unit frame 31 and a supply unit lid 32. The supply unit frame 31 has a toner discharge port 31a for discharging toner from the toner storage unit toward the developing unit 15. The toner discharge port 31a is positioned to face the replenishment port 21c (Figure 5) of the process cartridge B when the toner cartridge C is installed in the printer body A. The communication between the toner discharge port 31a and the replenishment port 21c enables toner replenishment to the process cartridge B. A shutter member 34 is provided on the outside of the supply unit frame 31 that opens the closed toner discharge port 31a in conjunction with the installation of the toner cartridge C into the printer body A.

[0053] The toner storage section 30a is equipped with a replenishment screw 35, which serves as a screw member for transporting toner toward the toner discharge port 31a, and an agitation and transport unit 36, which serves as an agitation and transport member for agitating the toner and transporting it toward the replenishment screw 35.

[0054] Both the replenishment screw 35 and the agitation and conveying unit 36 ​​convey and agitate the toner by rotating around a rotation axis that extends in the longitudinal direction. In other words, both the replenishment screw 35 and the agitation and conveying unit 36 ​​are examples of toner conveying means for conveying toner. The agitation and conveying unit 36 ​​has a shaft portion 36a that rotates when driven by a driving force, and an agitation portion 36b that protrudes radially from the shaft portion 36a and conveys and agitates the toner by rotating together with the shaft portion 36a. The shaft portion 36a extends in the longitudinal direction so as to penetrate the toner storage portion 30a. The agitation portion 36b is formed of, for example, a flexible resin sheet. The toner conveyed to the toner discharge port 31a by the agitation and conveying unit 36 ​​and the replenishment screw 35 is discharged from the toner discharge port 31a by the pump unit 37.

[0055] As shown in Figure 13(a, b), the pump unit 37 includes a pump 37a configured to change its internal volume by expanding and contracting in the longitudinal direction of the toner cartridge C, and a cam 37b rotatably arranged coaxially with the pump 37a. Furthermore, the pump unit 37 includes a link arm 37c that moves linearly in the longitudinal direction as the cam 37b rotates, thereby expanding and contracting the pump 37a in the longitudinal direction.

[0056] The pump 37a has a cylindrical outer shape, and the side surface of the cylindrical shape is formed in a bellows-like manner. Therefore, the pump 37a is expandable and contractible in the direction along the central axis of the cylindrical shape. The cam 37b and link arm 37c constitute a cam mechanism that drives the pump 37a by converting the rotational driving force input to the toner cartridge C into linear motion in the contraction direction and the opposite extension direction of the pump 37a.

[0057] <Drive configuration of the toner supply unit> The drive configuration of the toner supply unit 30 will be explained using Figures 7 and 13(a, b). As shown in Figure 13(a, b), the toner supply unit 30 has a stirring drive input unit 38 (first drive input unit) that drives the stirring conveying unit 36, and a pump / screw drive input unit 39 (second drive input unit) that drives the pump unit 37 and the replenishment screw 35. Both the stirring drive input unit 38 and the pump / screw drive input unit 39 are located on one longitudinal end (drive side) of the toner cartridge C.

[0058] Since the toner cartridge C is provided with separate agitation drive input unit 38 and pump / screw drive input unit 39, the agitation conveying unit 36, the pump unit 37, and the replenishment screw 35 can be independently driven and controlled. Specifically, the agitation conveying unit 36 ​​is driven continuously during image formation, while the pump unit 37 and the replenishment screw 35 are driven intermittently only when toner replenishment to the process cartridge B is required. The timing when toner replenishment is required is determined by the control unit of the printer body A based on the detection signal from the remaining amount detection means described above.

[0059] Viewed in the longitudinal direction, the stirring drive input unit 38 is located next to the stirring drive gear 38b, which transmits rotational driving force to the stirring conveying unit 36. The stirring drive gear 38b is located coaxially with the stirring conveying unit 36 ​​and at one longitudinal end, and rotates integrally with the stirring conveying unit 36. The stirring drive gear 38b receives the driving force from the stirring drive input unit 38 and rotates the stirring conveying unit 36 ​​in the R1 direction in Figure 7. The rotation of the stirring conveying unit 36 ​​in the R1 direction causes the toner in the toner storage unit 30a to be conveyed toward the replenishment screw 35.

[0060] Viewed in the longitudinal direction, a cam drive gear 39a is provided next to the pump / screw drive input section 39, which rotates in response to the driving force from the pump / screw drive input section 39. Next to the cam drive gear 39a, a cam gear 39b is provided, which rotates in response to the driving force from the cam drive gear 39a. The cam gear 39b is integrally formed with the cam 37b. Therefore, as the pump / screw drive input section 39 rotates, the cam gear 39b rotates, causing the cam 37b of the pump unit 37 to rotate. As a result of the rotation of the cam 37b, the link arm 37c moves linearly in the longitudinal direction, and the pump 37a extends and retracts.

[0061] Viewed longitudinally, a screw drive gear 39c is provided next to the cam gear 39b, which transmits rotational driving force to the replenishment screw 35. The screw drive gear 39c is coaxial with the replenishment screw 35 and located at one longitudinal end, and rotates integrally with the replenishment screw 35. The screw drive gear 39c receives driving force from the cam gear 39b and rotates the replenishment screw 35. The rotation of the replenishment screw 35 transports the toner in the toner storage section 30a longitudinally toward the toner discharge port 31a.

[0062] As shown in Figures 6 and 13(a, b), a drive-side side cover 50 is provided at the drive-side end of the toner cartridge C. The drive-side side cover 50 is fixed to the toner storage section 30a (supply section frame 31). The drive-side side cover 50 is part of the frame of the toner cartridge C. The drive-side side cover 50 rotatably supports the agitation drive input section 38 and the pump / screw drive input section 39.

[0063] Furthermore, the drive-side cover 50 is provided with a positioning boss 50a and a guided portion 50b. As will be described later, these components have the function of regulating the orientation of the toner cartridge C when it is installed in the printer body A.

[0064] <Waste Toner Collection Department> Next, an overview of the waste toner collection unit 40 will be described. As shown in Figure 8, the waste toner collection unit 40 includes a waste toner storage unit 40a for storing waste toner. The waste toner storage unit 40a is formed by a storage unit frame 41 and a storage unit lid 42. The storage unit lid 42 is provided with a waste toner receiving port 42a for receiving waste toner recovered from the process cartridge. The waste toner collection unit 40 has a shutter member 43 that opens and closes the waste toner receiving port 42a. The shutter member 43 opens and closes in the direction of arrow R3 in conjunction with the attachment and detachment of the toner cartridge C to the printer body A.

[0065] As shown in Figure 13(a, b), a partition member 46 and a first waste toner screw 44 and a second waste toner screw 45, which serve as waste toner transport means for transporting waste toner within the waste toner storage section 40a, are arranged inside the waste toner storage section 40a. The first waste toner screw 44 transports the waste toner that has fallen from the waste toner receiving port 42a in the longitudinal direction of the toner cartridge C. The second waste toner screw 45 obtains driving force from the first waste toner screw 44 and transports the waste toner that has been transported by the first waste toner screw 44 diagonally upward.

[0066] The waste toner collection unit 40 is driven as follows. As shown in Figure 13(a, b), the agitation conveying unit 36 ​​is provided with an agitation non-drive side gear 38a on the longitudinal side opposite to the agitation drive side gear 38b. The driving force input to the agitation drive input unit 38 on the drive side of the toner supply unit 30 is transmitted to the non-drive side of the toner supply unit 30 via the agitation conveying unit 36 ​​and then transmitted to the agitation non-drive side gear 38a.

[0067] Viewed in the longitudinal direction, a gear train 710 is provided next to the non-driven agitation gear 38a for transmitting power to the first waste toner screw 44 in the waste toner storage section 40a. In other words, the first waste toner screw 44 rotates by receiving rotational driving force from the printer body A via the agitation drive input section 38, the agitation drive gear 38b, the agitation transport unit 36, the non-driven agitation gear 38a, and the gear train 710.

[0068] As shown in Figures 6 and 13(a, b), a non-drive side cover 60 is provided at the non-drive side (waste toner collection unit 40 side) of the toner cartridge C. The non-drive side cover 60 is fixed to the waste toner storage unit 40a (storage unit frame 41). The non-drive side cover 60 is part of the frame of the toner cartridge C.

[0069] Furthermore, the non-drive side cover 60 is provided with a positioning boss 60a and a guided portion 60b. As will be described later, these components have the function of regulating the orientation of the toner cartridge C when it is installed in the printer body A.

[0070] <How to install and remove process cartridges and toner cartridges> Next, the method for attaching and detaching process cartridge B and toner cartridge C to and from printer body A will be explained using Figures 11(a, b) and 12(a-c). Figure 11(a, b) is a perspective view illustrating the attachment of process cartridge B and toner cartridge C to printer body A. Figure 12(a-c) is a side view illustrating the attachment of process cartridge B and toner cartridge C to printer body A.

[0071] As shown in Figure 11(a), the printer body A has a mounting section inside, which is a space for installing the process cartridge B and the toner cartridge C. The printer body A has an opening / closing door 107 on its outer surface that is rotatable (openable and closable) around the pivot axis R5 relative to the printer body A. Figures 11(a, b) show the opening / closing door 107 in the open position. By opening the opening / closing door 107, the mounting section inside the printer body A is exposed to the outside of the printer body A. The printer body A also has guide sections 108 and 109.

[0072] As shown in Figures 9(a, b), upper bosses 93, 94, lower bosses 95, 96, and tip bosses 97, 98 are provided at both longitudinal ends of the process cartridge B. Specifically, on the drive-side side of the process cartridge B, the upper boss 94, the lower boss 96 located below the upper boss 94, and the tip boss 98 located downstream of the upper boss 94 in the mounting direction D are arranged. On the non-drive-side side of the process cartridge B, the upper boss 93, the lower boss 95 located below the upper boss 93, and the tip boss 97 located downstream of the upper boss 93 in the mounting direction D are arranged. The upper bosses 93, 94 function as first guided parts guided by the guide parts 108, 109 of the printer body A. The tip bosses 97, 98 function as second guided parts guided by the guide parts 108, 109 of the printer body A. Furthermore, the stay 21 of process cartridge B has toner cartridge positioning sections 21a and 21b (Figure 9(b)).

[0073] As shown in Figures 13(a, b), the toner cartridge C is provided with positioning bosses 50a, 60a and guided portions 50b, 60b. The positioning bosses 50a, 60a are provided at both ends in the longitudinal direction of the toner cartridge C, and the guided portions 50b, 60b are also provided at both ends in the longitudinal direction of the toner cartridge C. Furthermore, in the mounting direction D (Figure 11(b)), the guided portions 50b, 60b are located upstream of the positioning bosses 50a, 60a in the mounting direction.

[0074] First, process cartridge B is installed into the printer body A. As shown in Figures 11(a) and 12(a), process cartridge B is inserted in the installation direction D while being guided by guide sections 108 and 109. At this time, on the drive side, the upper boss 94 and tip boss 98 rest on the guide section 109, and the guide section 109 is sandwiched between the upper boss 94 and tip boss 98 and the lower boss 96. On the non-drive side, the upper boss 93 and tip boss 97 rest on the guide section 108, and the guide section 108 is sandwiched between the upper boss 93 and tip boss 97 and the lower boss 95. As a result, process cartridge B moves in the installation direction D while being guided by guide sections 108 and 109. That is, the installation direction D of process cartridge B is the direction in which process cartridge B moves along the guide sections 108 and 109.

[0075] More specifically, the mounting direction D of process cartridge B, when viewed longitudinally, is the direction along a virtual straight line connecting the lower surface of the upper boss 93 (first guided portion) and the lower surface of the tip boss 97 (first guided portion), as shown in Figure 16(a, b). This virtual straight line is a common tangent to the tip boss 97 and the upper boss 93 from below. The reason why the mounting direction D is the direction along the virtual straight line connecting the lower surface of the upper boss 93 and the lower surface of the tip boss 97 is that process cartridge B is supported by the guide portion 108 at two points, the lower surface of the tip boss 97 and the lower surface of the upper boss 93, while being guided during mounting. Alternatively, the mounting direction D may be the direction along the virtual straight line connecting the lower surface of the tip boss 98 and the lower surface of the upper boss 94.

[0076] After installing process cartridge B into printer body A, install toner cartridge C into printer body A. As shown in Figures 11(b) and 12(b), place the guided portions 50b and 60b of toner cartridge C on the guide portions 108 and 109 of printer body A, respectively, and insert in the installation direction D. The direction in which toner cartridge C moves along guide portions 108 and 109 is the installation direction of toner cartridge C.

[0077] Figure 12(c) shows the toner cartridge C installed to the insertion completion position. In this state, the positioning bosses 50a and 60a (Figure 13(a, b)) of the toner cartridge C fit into the toner cartridge positioning sections 21a and 21b (Figure 9(b)) of the process cartridge B. In this state, the leading edges of the guided sections 50b and 60b in the installation direction are separated from the guide sections 108 and 109, while the rear ends of the guided sections 50b and 60b contact the guide sections 108 and 109. This positions the toner cartridge C within the process cartridge B. Furthermore, the contact of the rear ends of the guided sections 50b and 60b with the guide sections 108 and 109 determines the position of the toner cartridge C within the printer body A.

[0078] After installing process cartridge B and toner cartridge C, closing the opening / closing door 107 will put printer 1 into a state where it can perform image formation.

[0079] When removing toner cartridge C and process cartridge B, follow the reverse procedure described above. That is, after opening the opening / closing door 107, first pull out toner cartridge C in the opposite direction to the installation direction D, and then pull out process cartridge B in the opposite direction to the installation direction D.

[0080] <Means for detecting remaining amount> The configuration of the remaining amount detection means for detecting the remaining amount of toner (remaining amount of developer) in the developing unit 15 will be described. In this embodiment, a light transmission type detection mechanism is used as the remaining amount detection means.

[0081] Figure 14(a) is a perspective view showing a part of the developing unit 15, and Figure 14(b) is a magnified view of a further part of it (the area X1). Figure 15 is an exploded view showing the components of the light transmission detection mechanism (light guide 410 and light guide cover 420) removed from the developing unit 15.

[0082] As shown in Figure 14(a, b), the developing unit 15 is provided with a light guide 410 as a light guide means and a light guide cover 420 that covers a part of the light guide 410. The light guide 410 is formed of a light guide (light-transmitting member) that transmits detection light used to detect the remaining amount of toner.

[0083] Furthermore, as shown in Figure 15, the developing frame 415, which is the container (developing container) forming the developer storage chamber 152 of the developing unit 15, is provided with a remaining amount detection opening 416. The light guide 410 is attached to the developing frame 415 so as to cover the remaining amount detection opening 416. In other words, a part of the light guide 410 is exposed to the internal space (developer storage chamber 152) of the developing frame 415 through the remaining amount detection opening 416. The longitudinal position of the remaining amount detection opening 416 is shown in Figure 2. The light guide 410 is omitted in Figure 2.

[0084] As shown in Figure 14(a), the light guide 410 has a detection light incident surface 410a, an internal emission surface 410b, an internal emission surface 410c, and a detection light emission surface 410d. The detection light incident surface 410a and the detection light emission surface 410d are located outside the developing frame 415 (container). The internal emission surface 410b and the internal emission surface 410c are located inside the developing frame 415 (container). The detection light incident surface 410a and the detection light emission surface 410d may be planar (for example, planar parallel to the mounting surface 451c of the sensor substrate 451 described later). Alternatively, one or both of the detection light incident surface 410a and the detection light emission surface 410d may be curved in a convex shape to improve parallelism or light focusing.

[0085] The portion of the light guide 410 connecting the detection light incident surface 410a and the internal exit surface 410b is an input-side light guide section 411 that guides the detection light incident on the detection light incident surface 410a to the developer storage chamber 152 inside the developing frame 415. The internal exit surface 410b and the internal incident surface 410c face each other in the developer storage chamber 152, forming a spatial light path that crosses a part of the space where the developer is stored. The portion of the light guide 410 connecting the internal incident surface 410c and the detection light exit surface 410d is an output-side light guide section 412 that guides the detection light incident on the internal incident surface 410c from the spatial light path in the developer storage chamber 152 to the outside of the developing frame 415.

[0086] The detection light incident surface 410a and the detection light emission surface 410d are positioned to face the light-emitting element and light-receiving element of the printer body A, respectively, when the process cartridge B is installed in the printer body A. Therefore, the light guide 410 forms an optical path through which light emitted from the light-emitting element outside the container reaches the light-receiving element outside the container via the internal space of the container.

[0087] Specifically, as shown in Figure 14(a), the detection light emitted by the light-emitting element of the printer body A travels in the direction of arrow L1, enters the detection light incident surface 410a of the light guide 410, and travels inside the input-side light guide section 411 (arrow L2). Subsequently, the detection light is emitted from the internal exit surface 410b inside the developing frame 415, crosses the spatial light path of the developer storage chamber 152, and enters the internal incident surface 410c (arrow L3). Furthermore, the detection light travels inside the output-side light guide section 412 (arrow L4), and is emitted from the detection light exit surface 410d outside the developing frame 415 towards the light-receiving element (arrow L5).

[0088] Of the optical paths described above, the spatial optical path in the developer storage chamber 152 is blocked by the toner being agitated by the agitating member 154 (Figures 3-5) located in the developer storage chamber 152. Therefore, the control unit of the printer body A can estimate the amount of toner in the developer storage chamber 152 by obtaining a detection signal from the light-receiving element while the light-emitting element emits light, and by measuring the length of time the detection light is blocked.

[0089] <Shape of the light guide> The detailed shape of the light guide 410 in this embodiment will now be described. The input-side light guide 411 has an incident section 411a (Figures 14(b) and 17(b)) having a detection light incident surface 410a, an intermediate emission section 411c having an internal emission surface 410b, and a connecting section 411b (Figure 14(a)) connecting the incident section 411a and the intermediate emission section 411c. The incident section 411a is formed in a cylindrical shape, which is an example of a columnar shape. The direction of the central axis of the cylindrical shape of the incident section 411a (first direction) is substantially parallel to the optical axis direction of the light-emitting element (arrow L1), except for unavoidable differences such as shape tolerances during the manufacturing of the incident section 411a and inclination tolerances during the mounting of the light-emitting element. The connecting section 411b is bent approximately perpendicular to the incident section 411a and extends in the longitudinal direction (arrow Z) of the process cartridge B. The intermediate injection section 411c is bent approximately perpendicular to the connecting section 411b.

[0090] The output-side light guide section 412 includes an output section 412a (Figures 14(b) and 17(b)) having a detection light output surface 410d, an intermediate incident section 412c having an internal incident surface 410c, and a connecting section 412b (Figure 14(a)) connecting the output section 412a and the intermediate incident section 412c. The output section 412a is formed in a prismatic shape. The direction of the central axis of the prismatic shape of the output section 412a (first direction) is substantially parallel to the direction of the optical axis of the light-emitting element (arrow L1). The connecting section 412b is bent substantially perpendicular to the output section 412a and extends in the longitudinal direction of the process cartridge B (arrow Z). The intermediate incident section 412c is bent substantially perpendicular to the connecting section 412b.

[0091] As described above, in this embodiment, the detection light incident surface 410a and detection light emission surface 410d of the light guide 410 and the spatial light path in the developer storage chamber 152 are located at positions separated in the longitudinal direction (arrow Z) of the process cartridge B. Furthermore, both the input-side light guide section 411 and the output-side light guide section 412 of the light guide 410 have multiple bends. However, as will be explained below, the light guide cover 420 is provided with a configuration that can reduce stray light, so that the remaining toner amount can be detected with high detection accuracy even when the optical path length of the light guide is long or when the optical path of the light guide has multiple bends. In other words, the following configuration of the light guide cover 420 makes it possible to improve the degree of freedom of placement while maintaining the detection accuracy of the remaining amount detection means.

[0092] In this embodiment, the input-side light guide 411 and the output-side light guide 412 are integrally molded from a transparent resin material, but the input-side light guide 411 and the output-side light guide 412 may be separate components. Furthermore, the shape of the light guide 410 can be changed as appropriate. For example, the incident portion 411a of the input-side light guide 411 may be a columnar shape other than a cylindrical shape (e.g., a rectangular prism shape). In the case of an incident portion 411a with a columnar shape other than a cylindrical shape, the center line of the incident portion 411a is a virtual straight line extending parallel to the height direction of the columnar shape, and means a virtual straight line that passes through the center of the surface of the detection light incident surface 410a when viewed in the height direction. Furthermore, the columnar incident portion 411a may have a slight incline on its side surface, for example, so that the cross-sectional area of ​​the cross section perpendicular to the height direction becomes smaller as it approaches the detection light incident surface 410a, taking into consideration the ease of mold removal during resin molding.

[0093] <Printer body configuration> Next, the configuration of the printer body will be explained using Figures 14(a, b), 16, and 17(a, b). Figure 16 is a top view showing the process cartridge B installed in printer body A and a part of printer body A. Figure 17(a) is a cross-sectional view obtained by cutting the process cartridge B installed in printer body A and a part of printer body A with a virtual plane perpendicular to the longitudinal direction (Z) (the line z1-z1 in Figure 16). Figure 17(b) is an enlarged view showing a part of Figure 17(a) (the range of X2).

[0094] As shown in Figure 17(a, b), a sensor unit 450 is located in the printer body A. The sensor unit 450, together with the light guide 410 and light guide cover 420 of the process cartridge B, constitutes a light transmission detection mechanism, which is the remaining amount detection means of this embodiment.

[0095] The sensor unit 450 includes a sensor substrate 451, an LED 451a as a light-emitting element and a phototransistor 451b as a light-receiving element mounted on the mounting surface of the sensor substrate 451. The detection light emitted by the LED 451a reaches the phototransistor 451b via a spatial light path in the developer storage chamber 152 of the developing unit 15, through the light guide 410 with the configuration described above, and is converted into an electrical signal by the phototransistor 451b.

[0096] Furthermore, the sensor unit 450 includes a substrate holder 452 that holds the sensor substrate 451, and a support member 453 that movably supports the substrate holder 452. The support member 453 is fixed to the frame of the printer body A, while the sensor substrate 451 and substrate holder 452 move as the process cartridge B is attached and detached. The movement of the sensor substrate 451 and substrate holder 452 will be described later.

[0097] The sensor unit 450 is positioned above the photosensitive drum 11 and at the non-driven end of the process cartridge B in the longitudinal direction. The detection light incident surface 410a and detection light emission surface 410d of the light guide 410, which are opposite the light-emitting element and light-receiving element of the sensor unit 450, are also positioned above the photosensitive drum 11 and at the non-driven end of the process cartridge B in the longitudinal direction. The entire light guide 410 is positioned above the photosensitive drum 11 and extends from the detection light incident surface 410a and detection light emission surface 410d toward the longitudinal center of the process cartridge B.

[0098] Here, a drive train is arranged on the drive-side portion of the process cartridge B to input drive from the printer body A to the process cartridge B and to distribute and transmit the input drive to each part of the process cartridge B. In this embodiment, the components of the remaining amount detection means are arranged in the space above the photosensitive drum 11, making it easier to secure space for the gears and other components that make up the drive train.

[0099] Figure 23 is a perspective view showing the drive train of process cartridge B. For illustrative purposes, the side cover 7 and bearing member 5 of process cartridge B are omitted from the illustration. Process cartridge B has a developing coupling 155 as an input member that receives driving force from the printer body A. The developing coupling 155 is positioned on the pivot axis of the developing unit 15. As shown in Figures 10(a, b) and 23, the drive input to the developing coupling 155 is distributed and transmitted to each driven object in each unit (10, 15) via the drive trains 601, 601a of the cleaning unit 10 and the drive train 602 of the developing unit 15. Examples of driven objects include the developing roller 16, supply roller 13, agitator 154, screw of the receiving chamber 153 of the developing unit 15, photosensitive drum 11 of the cleaning unit 10, and screws 71, 75 that transport waste toner.

[0100] Furthermore, a contact for applying a bias voltage for performing the electrophotographic process is provided on the non-driven side of the process cartridge B (Figure 21). In addition, in the space on the non-driven side of the printer body A relative to the process cartridge B, a contact and circuit board for applying the bias voltage to the contacts of the process cartridge B, and a control board that acts as a control unit for controlling the various actuators of the printer body A are arranged. In this embodiment, since the components of the remaining amount detection means are arranged in the space above the photosensitive drum 11, it is easier to secure space for electrical components such as contacts, circuit boards, and control boards.

[0101] The contacts for applying the bias voltage to carry out the electrophotographic process are, for example, contacts E1 to E3 of the developing unit 15 shown in Figure 21. Contact E1 is connected to contact E4 of the printer body A (Figure 11(a)), enabling the application of voltage to the developing roller 16. Contact E2 is connected to contact E5 of the printer body A (Figure 11(a)), enabling the application of voltage to the supply roller 13. Contact E3 is connected to contact E6 of the printer body A (Figure 11(a)), enabling the application of voltage to the developing blade 18.

[0102] As described above, in this embodiment, the sensor unit 450 and light guide 410, which constitute the remaining amount detection means, are arranged in the space above the photosensitive drum 11, making it easier to utilize the space on both sides of the process cartridge B in the longitudinal direction for other purposes. As a result, the volume of the printer body A can be used more efficiently compared to, for example, the case where the sensor unit 450 is positioned opposite the drive side or non-drive side of the process cartridge B, and the overall size of the printer 1 can be reduced.

[0103] <Light Guide Cover> Next, the light guide cover 420, which is a cover member of this embodiment, will be described. As shown in Figure 15, the light guide cover 420 is attached to the developing unit 15.

[0104] As shown in Figures 14(a, b) and 17(a, b), the light guide cover 420 has a first hole 420a that fits with the input-side light guide 411 and exposes the detection light incident surface 410a, and a second hole 420b that fits with the output-side light guide 412 and exposes the detection light emission surface 410d. In other words, the light guide cover 420 has a first hole 420a as a first opening that exposes the incident surface of the light guide means, and a second hole 420b as a second opening that exposes the emission surface of the light guide means. When the process cartridge B is installed, the side of the light guide cover 420 on the sensor substrate 451 side is the outer surface of the light guide cover 420. The back side of the outer surface of the light guide cover 420 (the side facing the developing frame 415) is the inner surface of the light guide cover 420.

[0105] Furthermore, the light guide cover 420 is positioned to cover a portion of the surface of the light guide 410 other than the detection light incident surface 410a and the detection light emission surface 410d, as viewed from the sensor substrate 451 side. Specifically, the light guide cover 420 covers a portion of the incident surface 411a of the input-side light guide 411 with the peripheral wall of the first hole 420a, and covers a portion of the emission surface 412a of the output-side light guide 412 with the peripheral wall of the second hole 420b. The light guide cover 420 may also be formed to cover the entire surface of the light guide 410 other than the detection light incident surface 410a and the detection light emission surface 410d, as viewed from the sensor substrate 451 side.

[0106] The light guide cover 420 protects the detection light incident surface 410a and the detection light emission surface 410d, which are the surfaces on which the light guide 410 inputs and outputs detection light to and from the sensor substrate 451. In addition, the light guide cover 420 reduces false detections of toner level caused by light incident on the light guide 410 from surfaces other than the detection light incident surface 410a and light emitted from surfaces other than the detection light emission surface 410d, thereby contributing to improved detection accuracy.

[0107] Furthermore, in this embodiment, in a configuration where the sensor unit 450 is positioned above the photosensitive drum 11, the light guide cover 420 is positioned below the sensor unit 450. This prevents the surface of the photosensitive drum 11 from being exposed due to light leakage from the LED 451a. For example, in a configuration where the LED 451a overlaps the photosensitive drum 11 when viewed vertically (Figure 17(a)), it is preferable that a part of the light guide cover 420 exists between the LED 451a and the photosensitive drum 11 in the vertical direction and overlaps with the LED 451a when viewed vertically.

[0108] Furthermore, as will be described later, the light guide cover 420 contacts the sensor unit 450 of the printer body A when the process cartridge B is installed, thereby positioning the detection light incident surface 410a and the detection light emission surface 410d relative to the sensor substrate 451. In other words, the first hole 420a and the second hole 420b have the function of positioning the detection light incident surface 410a and the detection light emission surface 410d.

[0109] <Recess in the light guide cover> As described above, in this embodiment, providing the light guide cover 420 offers advantages such as protection of the light guide 410, improved accuracy of toner level detection, and prevention of exposure of the photosensitive drum 11. However, the light guide cover 420 may also cause false detections. Specifically, if the light guide cover 420 is located near the light-emitting element, the detection light reflected from the surface of the light guide cover 420 itself may reach the photoreceiving element without passing through the light guide 410.

[0110] More specifically, as shown in Figure 17(b), the detection light emitted by the LED 451a is projected with a spatial spread (direction angle) centered on the optical axis (arrow L1). To capture as much light as possible into the light guide 410, it is desirable to position the detection light incident surface 410a close to the LED 451a. However, considering the attachment and detachment of the process cartridge B and the contact and separation of the developing unit 15, it is desirable to position the detection light incident surface 410a at a certain distance from the LED 451a. In that case, some of the detection light may be reflected by the light guide cover 420 and reach the phototransistor 451b as light that does not pass through the light guide 410 and does not contribute to toner level detection (i.e., stray light), potentially causing erroneous detection of toner level or a decrease in accuracy.

[0111] Therefore, in this embodiment, the shape of the light guide cover 420 is used to control the direction in which stray light that does not enter the detection light incident surface 410a travels.

[0112] Specifically, as shown in Figures 14(b), 17(b), and 18, a recess 425 is formed on the outer surface of the light guide cover 420 between the first hole 420a and the second hole 420b. Figure 18 is a further enlarged view of a part of Figure 17(b) to illustrate the shape of the light guide cover 420. In the cross-sections of Figures 17(b) and 18, the recess 425 is a concave shape in which a part of the upstream surface (outer surface) of the light guide cover 420 in the first direction D1 is recessed downstream in the first direction D1 between the inlet portion 411a and the outlet portion 412a in the second direction D2.

[0113] Here, Figures 17(b) and 18 show a cross-section of the apparatus with a virtual plane that extends in the first direction D1 and the second direction D2 and passes through the inlet section 411a and the outlet section 412a. In other words, the direction that intersects both the first direction D1 and the second direction D2 is defined as the third direction, and Figures 17(b) and 18 show a cross-section perpendicular to the third direction (which in this embodiment is the same as the longitudinal direction of the process cartridge B (arrow Z)).

[0114] The first direction D1 is the direction along the centerline of the columnar incident section 411a, and is the direction from the outer surface side to the inner surface side of the light guide cover 420. The first direction D1 can be rephrased as the direction in which the detected light travels through the inside of the incident section 411a, that is, the optical axis direction in the incident section 411a. The second direction D2 is the direction that intersects the first direction D1, and is the direction in which the incident section 411a and the output section 412a are aligned. The first direction D1 is substantially the same direction as the normal direction of the mounting surface of the sensor substrate 451 on which the LED 451a is mounted.

[0115] The bottom surface 425c of the recess 425 is inclined such that in the second direction D2, the distance from the inlet side 411a to the outlet side 412a decreases. In other words, the end of the bottom surface 425c on the inlet side (first end 425a) is located downstream in the first direction D1 than the end of the bottom surface 425c on the outlet side (second end 425b).

[0116] Furthermore, the bottom surface 425c of the recess 425 is curved between the first end 425a and the second end 425b so as to be recessed downstream in the first direction D1 with respect to the virtual straight line Ln1 connecting the first end 425a and the second end 425b.

[0117] As described above, in this embodiment, a recess 425 is provided in the light guide cover 420, and its bottom surface 425c is provided with a slope and curvature. With this configuration, as shown in Figure 18, when a portion of the light emitted from the LED 451a, which is located opposite the incident part 411a and the first direction D1, enters the recess 425, the bottom surface 425c of the recess 425 reflects the light generally toward the LED 451a. In other words, the direction of stray light can be controlled so that stray light entering the recess 425 from the LED 451a is reflected toward the LED 451a. This reduces the amount of stray light that reaches the phototransistor 451b after being reflected by the light guide cover 420.

[0118] The cross-sectional shape of the bottom surface 425c of the recess 425 (Figure 18) is preferably an arc shape (dotted line) centered on point C1 located within the region obtained by projecting the detection light incident surface 410a in the first direction D1. This ensures that when an LED 451a is positioned near this point, the direction in which the bottom surface 425c reflects light from the LED 451a is concentrated near the LED 451a, allowing for more effective control of the direction of stray light. It is even more preferable that the LED 451a is positioned at the center of the arc drawn by the bottom surface 425c.

[0119] The three-dimensional shape of the bottom surface 425c of the recess 425 is preferably spherical, centered on a point C1 located within the region obtained by projecting the detection light incident surface 410a in the first direction D1. This ensures that when an LED 451a is positioned near this point, the direction in which the bottom surface 425c reflects light from the LED 451a is concentrated near the LED 451a, allowing for more effective control of the direction of stray light. It is even more preferable that the LED 451a is positioned at the center of the sphere traced by the bottom surface 425c.

[0120] Thus, according to this embodiment, it is possible to reduce false detection of toner levels and a decrease in detection accuracy due to stray light reflected from the light guide cover 420.

[0121] Furthermore, since the light guide cover 420 can be placed near the sensor substrate 451 without the effects of stray light reflected by the light guide cover 420 becoming apparent, various advantages can be obtained. For example, the light guide cover 420 can effectively block the detection light directed toward the photosensitive drum 11, making it possible to place the sensor substrate 451 near the photosensitive drum 11 and improving the degree of freedom in placement. In addition, since the effects of stray light are less likely to occur even when the light-emitting element and the light-receiving element are placed close together on the sensor substrate 451, it becomes possible to miniaturize the sensor substrate 451.

[0122] Since the input and output sides of the light guide 410 are interchangeable, the arrangement of the LED 451a and phototransistor 451b on the sensor board 451 may also be swapped. In that case, the recess 425 should have a shape that is inverted with respect to the second direction D2.

[0123] <Positioning configuration when cartridge is installed> The configuration for determining the relative positions of the detection light incident surface 410a and detection light emission surface 410d on the cartridge side and the LED 451a and phototransistor 451b on the printer body side when process cartridge B is installed will be explained using Figures 16 and 19(a, b).

[0124] Figures 19(a, b) show the area around the sensor unit 450 in Figure 16, viewed from below the light guide cover 420 (viewed in the direction of arrow D9 in Figure 17(b)). Figure 19(a) shows the process cartridge B in the process of being installed, and Figure 19(b) shows the process cartridge B after it has been installed. Also, the light guide 410 is not shown in Figures 19(a, b).

[0125] As shown in Figure 16, the substrate holder 452 that holds the sensor substrate 451 is biased in the direction of arrow H by a tension spring 454, which serves as a biasing means. The tension spring 454 is stretched between the substrate holder 452 and the support member 453. The biasing direction of the tension spring 454 (arrow H) is a direction that intersects obliquely with the mounting direction D of the process cartridge B, and includes a component opposite to the mounting direction D.

[0126] As shown in Figure 19(a), the substrate holder 452 has a first contact portion 452a that contacts the first contact portion 420d of the light guide cover 420, and a second contact portion 452b that contacts the second contact portion 420c of the light guide cover 420. The first contact portion 420d and the first contact portion 452a position the substrate holder 452 and the light guide cover 420 with respect to the mounting direction D. The second contact portion 420c and the second contact portion 452b position the substrate holder 452 and the light guide cover 420 with respect to the direction perpendicular to the mounting direction D (longitudinal direction).

[0127] Furthermore, the substrate holder 452 has an inclined surface 452s that contacts the third contact portion 420t of the light guide cover 420, thereby guiding the first contact portion 420d and the second contact portion 420c to the first contact portion 452a and the second contact portion 452b.

[0128] As shown in Figure 19(a), before the process cartridge B is installed, and before the light guide cover 420 contacts the substrate holder 452 during installation, the substrate holder 452 is positioned by the biasing force of the tension spring 454. In this case, the position of the substrate holder 452 partially overlaps with the position of the light guide cover 420 after the process cartridge B is installed.

[0129] Furthermore, the support member 453 that supports the substrate holder 452 is provided with covering portions 453a and 453b that cover the LED 451a and phototransistor 451b when the process cartridge B is not installed.

[0130] As the process cartridge B is inserted in the mounting direction D from the state shown in Figure 19(a), the third contact portion 420t of the light guide cover 420 comes into contact with the inclined surface 452s of the substrate holder 452. As a result of the pressure on the inclined surface 452s, the substrate holder 452 slides in the direction of arrow H1 against the biasing force of the tension spring 454, and the second contact portion 420c of the light guide cover 420 comes into contact with the second contacted portion 452b of the substrate holder 452.

[0131] As the process cartridge B is further inserted in the mounting direction D, the first contact portion 420d of the light guide cover 420 comes into contact with the first contact portion 452a of the substrate holder 452, and the substrate holder 452 slides in the direction of arrow H2 against the biasing force of the tension spring 454.

[0132] Then, when the process cartridge B is inserted to a predetermined mounting position (a position where image formation can be performed), the substrate holder 452 is positioned in a position moved from its initial position in the directions of arrows H1 and H2, as shown in Figure 19(b). In this state, the first contact portion 420d and the second contact portion 420c come into contact with the first contacted portion 452a and the second contacted portion 452b, respectively, so that the light guide cover 420 holds the substrate holder 452 against the biasing force of the tension spring 454.

[0133] In the positioning state shown in Figure 19(b), the sensor substrate 451 has moved together with the substrate holder 452 from the state shown in Figure 19(a), causing the LED 451a and phototransistor 451b to be exposed from the covers 453a and 453b of the support member 453. The first hole 420a of the light guide cover 420 faces the LED 451a, and the second hole 420b faces the phototransistor 451b. That is, the detection light incident surface 410a of the light guide 410 faces the LED 451a, and the detection light emission surface 410d faces the phototransistor 451b.

[0134] As shown in Figure 17(b), in the state after the process cartridge B is installed, the cover portion 453a of the support member 453 is positioned between the LED 451a and the phototransistor 451b in the second direction D2. In addition, the cover portion 453a is positioned between the sensor substrate 451 and the substrate holder 452 and the light guide cover 420 in the first direction D1. Therefore, the cover portion 453a can further reduce the possibility that light emitted from the LED 451a is reflected by the light guide cover 420 or the substrate holder 452 and reaches the phototransistor 451b as stray light.

[0135] In this way, when the cartridge is installed, the light guide cover 420 comes into contact with the substrate holder 452, causing the substrate holder 452 to move, thereby positioning the light guide 410 and the sensor substrate 451. This makes it possible to position the relative positions of the detection light incident surface 410a and the LED 451a, and the relative positions of the detection light emission surface 410d and the phototransistor 451b with high precision, thereby improving the accuracy of toner level detection.

[0136] As described above, the light guide cover 420 not only protects the light guide 410 and shields it from leaking detection light into the photosensitive drum 11, but also has the function of positioning the light guide 410 and the substrate holder 452.

[0137] Incidentally, as shown in Figures 17(b) and 18, the substrate holder 452 is provided with a restricting hole 452c for focusing the light emitted by the LED 451a. The restricting hole 452c allows the direction of light emission to be restricted even when the directional angle of the LED 451a is wide, thereby reducing the decrease in detection accuracy due to stray light and the leakage of light to the photosensitive drum 11.

[0138] Furthermore, the light guide cover 420 is provided with a protrusion 426 that projects toward the sensor substrate 451 between the recess 425 and the detection light emission surface 410d. The protrusion 426 is formed to intersect with a virtual straight line Ln2 connecting the LED 451a and the opening edge of the regulating hole 452c. By providing such a protrusion 426, the possibility of light reflected from the surrounding surface of the detection light emission surface 410d of the light guide cover 420 reaching the phototransistor 451b can be reduced.

[0139] <Positional relationship between the pivot axis and the light guide> Next, the positional relationship between the oscillation axis in process cartridge B and the inlet portion 411a and outlet portion 412a of the light guide 410 will be explained.

[0140] Figure 21 is a side view of process cartridge B as seen in the longitudinal direction (the direction of the rotation axis of the photosensitive drum 11). As described above, the developing unit 15 is pivotable around the oscillation axis 8 between a contact position where the developing roller 16 is in contact with the photosensitive drum 11 (Figure 20(a)) and a separated position where the developing roller 16 is separated from the photosensitive drum 11 (Figure 20(b)). Process cartridge B in Figure 21 is in the state where the developing roller 16 is in contact position (developing contact state).

[0141] As shown in Figure 21, when viewed in the longitudinal direction, with respect to a virtual straight line Ln3 drawn in the first direction D1 through the oscillation axis 8, the inlet portion 411a is positioned on one side of the second direction D2, and the outlet portion 412a is positioned on the other side of the second direction D2. In other words, when viewed in the longitudinal direction, if the two regions separated by the virtual straight line Ln3 are called the first region Ar1 and the second region Ar2, the inlet portion 411a is positioned in the first region Ar1, and the outlet portion 412a is positioned in the second region Ar2.

[0142] Here, the first direction D1 is the direction of the center line of the columnar incident portion 411a, and is the direction from the outside to the inside of the light guide 410 via the incident portion 411a. Alternatively, the first direction D1 can be said to be the direction of the optical axis of the incident portion 411a, and is the direction from the outside to the inside of the light guide 410. The second direction D2 is the direction that intersects the first direction D1, and is the direction in which the incident portion 411a and the output portion 412a are aligned. In this embodiment, the first direction D1 is substantially the same direction as the normal direction of the mounting surface 451c of the sensor substrate 451, and the second direction D2 is substantially parallel to the mounting surface 451c of the sensor substrate 451.

[0143] The advantages of this configuration will be explained using Figures 22(a, b). Figure 22(a) is a schematic diagram showing the arrangement of the pivot axis 8 and the inlet section 411a and outlet section 412a in this embodiment. Figure 22(b) is a schematic diagram showing the arrangement of the pivot axis 8 and the inlet section 411a and outlet section 412a in a comparative example.

[0144] In this embodiment (Figure 22(a)), the inlet portion 411a and the outlet portion 412a are positioned on one side and the other side of the second direction D2 with respect to a virtual straight line Ln3 drawn in the first direction D1 through the oscillation axis 8. On the other hand, in the comparative example (Figure 22(b)), both the inlet portion 411a and the outlet portion 412a are positioned on only one side of the second direction D2 (in this case, the left side in the figure) with respect to the virtual straight line Ln3.

[0145] During the image forming operation, the developing unit 15 is held in contact position, but the angle of the developing unit 15 around the oscillation axis 8 may fluctuate due to various factors. For example, as shown in Figure 23, the driving force input to the developing coupling 155 is distributed to each driven object (developing roller 16, etc.) of the developing unit 15 by a drive row provided at the drive-side end of the process cartridge B. At this time, the driving load of the driven objects fluctuates according to the amount of toner in the developing unit 15 and the rotation angle of the agitator 154. As a result of fluctuations in the load torque when the developing coupling 155 drives the drive row on the developing unit 15 side, the developing unit 15 may vibrate with a small range of fluctuation around the oscillation axis 8.

[0146] In Figure 22(a, b), the change in position of the light guide 410 when the developing unit 15 vibrates at an angle of Δθ will be explained. The value of Δθ is assumed to be the same in this embodiment and in the comparative example.

[0147] In the comparative example (Figure 22(b)), when the developing unit 15 swings clockwise in the figure at an angle Δθ, the incident portion 411a and the outgoing portion 412a of the light guide 410 move from the dashed line position to the solid line position. At this time, both the detection light incident surface 410a and the detection light outgoing surface 410d move closer to the mounting surface 451c of the sensor substrate 451 with respect to the first direction D1. In other words, the change in distance Δd3 between LED 451a and detection light incident surface 410a and the change in distance Δd4 between phototransistor 451b and detection light outgoing surface 410d always coincide in sign. This is because, with respect to a virtual straight line Ln3 drawn through the swing axis 8 in the first direction D1, both the incident portion 411a and the outgoing portion 412a are positioned on one side of the second direction D2 with respect to the virtual straight line Ln3. Furthermore, even when both the inlet section 411a and the outlet section 412a are positioned on the other side of the virtual straight line Ln2 (the right side in Figure 22(b)), the signs of the fluctuation amounts Δd3 and Δd4 will be the same.

[0148] In other words, in the comparative example, when vibration occurs in the developing unit 15, the distance between LED 451a and the detection light incident surface 410a and the distance between phototransistor 451b and the detection light output surface 410d increase or decrease simultaneously. Therefore, the variation in the optical path length from LED 451a to phototransistor 451b via the light guide 410 and the spatial optical path inside the container becomes large. As a result, the change in the amount of light reaching phototransistor 451b becomes large, and vibration in the developing unit 15 may affect the accuracy of toner level detection.

[0149] Furthermore, in the air layer between the light guide 410 and the LED 451a or phototransistor 451b, the amount of light varies greatly depending on the square of the optical path length. Also, when detecting the remaining toner amount based on the detection signal of the phototransistor 451b, the detection signal (e.g., voltage value) can be compared with a predetermined threshold to determine the length of time the spatial optical path within the container is blocked by the toner. Therefore, if the amount of light reaching the phototransistor 451b shifts significantly due to changes in the optical path length, the accuracy of toner amount detection may decrease.

[0150] In this embodiment (Figure 22(a)), when the developing unit 15 swings clockwise in the figure at an angle Δθ, the incident portion 411a and the outgoing portion 412a of the light guide 410 move from the dashed line position to the solid line position. At this time, the incident surface 410a of the detection light approaches the mounting surface 451c of the sensor substrate 451 with respect to the first direction D1, while the outgoing surface 410d of the detection light moves away from the mounting surface 451c of the sensor substrate 451 with respect to the first direction D1. In other words, the magnitude of the change in distance Δd1 between LED 451a and the incident surface 410a and the magnitude of the change in distance Δd2 between phototransistor 451b and the outgoing surface 410d are opposite. This is because the incident portion 411a and the outgoing portion 412a are positioned on one side and the other side of the second direction D2 with respect to a virtual straight line Ln3 drawn in the first direction D1 through the swing axis 8.

[0151] That is, in the present embodiment, even when vibration of the developing unit 15 occurs, an increase / decrease in the distance between the LED 451a and the detection light incident surface 410a cancels out an increase / decrease in the distance between the phototransistor 451b and the detection light exit surface 410d. Therefore, variation in the optical path length from the LED 451a to the phototransistor 451b via the light guide 410 and the spatial optical path in the container is reduced. This makes it possible to reduce the influence of vibration of the developing unit 15 and improve the detection accuracy of the remaining toner amount.

[0152] Further, in FIG. 22(a), let R1 be the distance from the swing axis 8 to the center of the detection light incident surface 410a, and let R2 be the distance from the swing axis 8 to the center of the detection light exit surface 410d. In FIG. 22(b), let R3 be the distance from the swing axis 8 to the center of the detection light incident surface 410a, and let R4 be the distance from the swing axis 8 to the center of the detection light exit surface 410d.

[0153] At this time, if the distance between the incident portion 411a and the exit portion 412a in the second direction D2 (the distance between the LED 451a and the phototransistor 451b) is the same, at least R1 < R3 holds. Therefore, when the developing unit 15 vibrates at an angle of Δθ (rad), the movement amount ΔL3 (≒ R3 × Δθ) of the detection light incident surface 410a in the comparative example is larger than the movement amount ΔL1 (≒ R1 × Δθ) of the detection light incident surface 410a in the present embodiment.

[0154] Note that in FIG. 22(b), when both the incident portion 411a and the exit portion 412a are arranged on the other side of the virtual straight line Ln2 (the right side in the drawing), at least R2 < R4 holds. Therefore, when the developing unit 15 vibrates at an angle of Δθ (rad), the movement amount ΔL4 (≒ R4 × Δθ) of the detection light exit surface 410d in the comparative example is larger than the movement amount ΔL2 (≒ R2 × Δθ) of the detection light exit surface 410d in the present embodiment.

[0155] Therefore, according to this embodiment, the amount of movement ΔL1 and ΔL2 of the detection light incident surface 410a and the detection light emission surface 410d due to vibration of the developing unit 15 can be kept small. As a result, the positions of the detection light incident surface 410a and the detection light emission surface 410d relative to the LED 451a and the phototransistor 451b are stabilized, which contributes to improved detection accuracy.

[0156] Furthermore, in this embodiment, the developing unit 15 is moved between the contact position and the separated position by the separation mechanism 100 described above (see Figure 20(a, b)). On the other hand, according to the configuration of this embodiment, the amount of movement (R1×θ, R2×θ) of the detection light incident surface 410a and the detection light emission surface 410d with respect to the oscillation angle θ of the developing unit 15 is kept smaller than in the comparative example. Therefore, the movement space of the light guide 410 accompanying the oscillation of the developing unit 15 is reduced. In other words, it becomes possible to secure the movement space of the light guide 410 without increasing the size of the process cartridge B, and this contributes to the miniaturization of the printer 1.

[0157] In this embodiment, the developing coupling 155, which is the drive input unit to the process cartridge B, is positioned on the oscillation axis 8. However, even if the drive input unit is located at a position different from the oscillation axis 8, vibration of the developing unit 15 may occur due to fluctuations in the drive load, etc. Therefore, the arrangement of the inlet unit 411a and outlet unit 412a described above is also applicable in such cases.

[0158] <Other Embodiments> In the above-described embodiment, a light transmission detection mechanism was explained as a means for detecting the remaining amount of process cartridge B. However, a similar light transmission detection mechanism may be used as a means for detecting the amount of toner in other cartridges. For example, it may be used as a means for detecting the remaining amount of toner in the toner supply unit 30 of toner cartridge C in the above-described embodiment, or as a means for detecting the amount of waste toner contained in the waste toner collection unit 40 (full-load detection means).

[0159] Furthermore, in the above-described embodiment, the input and output sides of the light transmission detection mechanism may be swapped. That is, the arrangement of the LED 451a and the phototransistor 451b on the sensor substrate 451 may be swapped, and the roles of the detection light incident surface 410a and the detection light emission surface 410d of the light guide 410 may be swapped. In this case, the incident part into which the detection light enters (emission part 412a in the embodiment) may remain in the shape of a rectangular prism, or it may be changed to a cylindrical shape or another columnar shape. Similarly, the emission part from which the detection light is emitted (incident part 411a in the embodiment) may remain in the shape of a cylindrical shape, or it may be changed to a rectangular prism shape or another columnar shape.

[0160] Furthermore, although the above-described embodiment described a configuration in which the process cartridge B and toner cartridge C are each installed in the printer body A, a configuration in which the process cartridge B and toner cartridge C are integrated into a single unit is also possible.

[0161] Furthermore, although the above-described embodiment explained an example in which a light transmission detection mechanism was used as a means for detecting the amount of toner inside the cartridge installed in the printer body, the developing unit may also be incorporated into the printer body.

[0162] Furthermore, although the above-described embodiment described an image forming apparatus having one image carrier, it is not limited to this and can also be applied to, for example, a color image forming apparatus having multiple image carriers and using multiple types of developers to form a color image.

[0163] <Summary of this disclosure> This disclosure includes at least the following components:

[0164] (Composition 1) It is a cartridge, A container configured to hold a developer, A light guiding means including an inlet portion configured to receive light from outside the cartridge, and an outlet portion configured to emit the light that has entered the container through the inlet portion to the outside of the cartridge, A cover member having a first opening through which the incident surface of the incident portion is exposed, and a second opening through which the exit surface of the exit portion is exposed, and covering a part of the light guide means, Equipped with, The incident portion has a columnar shape centered on the center line, When the direction of the center line is defined as the direction from the outer surface to the inner surface of the cover member as the first direction, the direction intersecting the first direction where the inlet portion and the outlet portion are aligned as the second direction, and the direction intersecting both the first and second directions as the third direction, In a cross-section perpendicular to the third direction, the cover member has a portion of its outer surface that is recessed on the downstream side in the first direction, between the inlet portion and the outlet portion in the second direction. The first end of the bottom surface of the recess on the inlet side in the second direction is located downstream in the first direction from the second end of the bottom surface on the outlet side in the second direction, and The bottom surface is curved such that it is recessed downstream in the first direction with respect to a virtual straight line connecting the first end and the second end, between the first end and the second end. A cartridge characterized by the following features.

[0165] (Configuration 2) It is a cartridge, A container configured to hold a developer, A light guiding means including an inlet portion configured to receive light from outside the cartridge, and an outlet portion configured to emit the light that has entered the container through the inlet portion to the outside of the cartridge, A cover member having a first opening through which the incident surface of the incident portion is exposed, and a second opening through which the exit surface of the exit portion is exposed, and covering a part of the light guide means, Equipped with, When the direction of the optical axis of the incident portion is defined as the direction from the outer surface to the inner surface of the cover member as the first direction, the direction intersecting the first direction and where the incident portion and the exit portion are aligned as the second direction, and the direction intersecting both the first and second directions as the third direction, In a cross-section perpendicular to the third direction, the cover member has a portion of its outer surface that is recessed on the downstream side in the first direction, between the inlet portion and the outlet portion in the second direction. The first end of the bottom surface of the recess on the inlet side in the second direction is located downstream in the first direction from the second end of the bottom surface on the outlet side in the second direction, and The bottom surface is curved such that it is recessed downstream in the first direction with respect to a virtual straight line connecting the first end and the second end, between the first end and the second end. A cartridge characterized by the following features.

[0166] (Composition 3) In the cross-section, the bottom surface of the recess is formed in an arc shape. The center of the arc-shaped bottom surface is located in a position that coincides with the incident portion when viewed in the first direction. A cartridge according to configuration 1 or 2, characterized by the above.

[0167] (Composition 4) The bottom surface of the recess is formed in a spherical shape. The center of the spherical bottom surface is located in a position that coincides with the incident portion when viewed in the first direction. A cartridge according to configuration 1 or 2, characterized by the above.

[0168] (Composition 5) The cover member has a protrusion provided between the second end of the bottom surface and the output surface of the light guide means in the second direction, and further has a protrusion that protrudes upstream in the first direction compared to the second end. A cartridge according to any one of configurations 1 to 4, characterized by the above.

[0169] (Composition 6) The cartridge further comprises a rotating image carrier and a developer carrier that develops an image on the surface of the image carrier using the developer, In the orientation when the cartridge is mounted on the main body of the image forming apparatus, the image carrier is positioned below the light-emitting element of the main body of the apparatus. At least a portion of the cover member is positioned between the light-emitting element and the image carrier in the vertical direction and is arranged to overlap with the image carrier when viewed from above. A cartridge according to any one of configurations 1 to 5, characterized by the above.

[0170] (Composition 7) The light guiding means further comprises an internal emission surface and an internal incidence surface provided inside the container, and is configured such that the light incident on the incidence surface of the incidence section is emitted from the internal emission surface, passes through the internal space of the container and is incident on the internal incidence surface, and is emitted from the emission surface of the emission section. The inlet and outlet portions are located at the ends of the cartridge in the direction of the rotation axis of the image carrier, The internal ejection surface and the internal injection surface are positioned closer to the center of the cartridge than the injection portion and the ejection portion in the direction of the rotation axis. The cartridge according to configuration 6, characterized by the features described above.

[0171] (Composition 8) The main body of the device, A cartridge according to any one of configurations 1 to 7 that is attached to the main body of the device, An image forming apparatus comprising, The device body comprises a light-emitting element that emits light, a light-receiving element that receives the light and emits a detection signal, and a substrate having a mounting surface on which the light-emitting element and the light-receiving element are mounted. The first direction is the direction normal to the mounting surface of the substrate, The second direction is parallel to the mounting surface. An image forming apparatus characterized by the following features.

[0172] (Composition 9) It is a cartridge, A first unit comprising an image carrier configured to be rotatable around a rotation axis, A second unit comprising a developer carrier configured to carry a developer and supply the developer to the image carrier, and a container for containing the developer, wherein the second unit is supported by the first unit so as to be able to pivot about a pivot axis extending in the direction of the rotation axis relative to the first unit, It has, The second unit has a light guiding means including an inlet portion configured to receive light from outside the cartridge, and an outlet portion configured to emit the light that has entered the container through the inlet portion to the outside of the cartridge. The incident portion has a columnar shape centered on the center line, When the direction of the center line is defined as the first direction, and when viewed in the direction of the rotation axis of the image carrier, the two regions separated by a virtual straight line passing through the oscillation axis and extending in the first direction are defined as the first region and the second region, the inlet portion is located in the first region and the outlet portion is located in the second region. A cartridge characterized by the following features.

[0173] (Composition 10) It is a cartridge, A first unit comprising an image carrier configured to be rotatable around a rotation axis, A second unit comprising a developer carrier configured to carry a developer and supply the developer to the image carrier, and a container for containing the developer, wherein the second unit is supported by the first unit so as to be able to pivot about a pivot axis extending in the direction of the rotation axis relative to the first unit, It has, The second unit has a light guiding means including an inlet portion configured to receive light from outside the cartridge, and an outlet portion configured to emit the light that has entered the container through the inlet portion to the outside of the cartridge. When the direction of the optical axis of the incident portion is defined as the first direction, and when viewed in the direction of the rotation axis of the image carrier, the two regions separated by a virtual straight line passing through the oscillation axis and extending in the first direction are defined as the first region and the second region, the incident portion is located in the first region and the output portion is located in the second region. A cartridge characterized by the following features.

[0174] (Composition 11) The second unit has a pressed portion that is pressed by an external pressing member of the cartridge, and when the pressed portion is pressed, the developer carrier moves from a contact position in contact with the image carrier to a separated position in separation from the image carrier. A cartridge according to configuration 9 or 10, characterized by the features described herein.

[0175] (Composition 12) The cartridge has an input member to which driving force is input from outside the cartridge, The input member is positioned on the pivot axis, The second unit has a drive train that receives driving force from the input member, A cartridge according to any one of the configurations 9 to 11, characterized by the features described herein.

[0176] (Composition 13) The main body of the device, A cartridge according to any one of configurations 9 to 12, which is attached to the main body of the device, An image forming apparatus comprising, The device body comprises a light-emitting element that emits light, a light-receiving element that receives the light and emits a detection signal, and a substrate having a mounting surface on which the light-emitting element and the light-receiving element are mounted. The first direction is the normal direction to the mounting surface of the substrate. An image forming apparatus characterized by the following features. [Explanation of Symbols]

[0177] A...Device body (printer body) / B...Cartridge (process cartridge) / 8...Oscillating axis / 10...First unit (cleaning unit) / 11...Image carrier (photosensitive drum) / 15...Second unit (developing unit) / 16...Developer carrier (developing roller) / 410...Light guide means (light guide) / 410a...Incident surface (detection light incident surface) / 410d...Output surface (detection light output surface) / 411a...Incident part / 412a...Output part / 415...Container (developing frame) / 420...Cover member (light guide cover) / 425...Recess / 425a...First end / 425b...Second end / 425c...Bottom surface / 451a...Light-emitting element (LED) / 451b...Photodetector (phototransistor) / D1...First direction / D2...Second direction

Claims

1. It is a cartridge, A container configured to hold a developer, A light guiding means including an inlet portion configured to receive light from outside the cartridge, and an outlet portion configured to emit the light that has entered the container through the inlet portion to the outside of the cartridge, A cover member having a first opening through which the incident surface of the incident portion is exposed, and a second opening through which the exit surface of the exit portion is exposed, and covering a part of the light guide means, Equipped with, The incident portion has a columnar shape centered on the center line, When the direction of the center line is defined as the direction from the outer surface to the inner surface of the cover member as the first direction, the direction intersecting the first direction where the inlet portion and the outlet portion are aligned as the second direction, and the direction intersecting both the first and second directions as the third direction, In a cross-section perpendicular to the third direction, the cover member has a portion of its outer surface that is recessed on the downstream side in the first direction, between the inlet portion and the outlet portion in the second direction. The first end of the bottom surface of the recess on the inlet side in the second direction is located downstream in the first direction from the second end of the bottom surface on the outlet side in the second direction, and The bottom surface is curved such that it is recessed downstream in the first direction with respect to a virtual straight line connecting the first end and the second end, between the first end and the second end. A cartridge characterized by the following features.

2. It is a cartridge, A container configured to hold a developer, A light guiding means including an inlet portion configured to receive light from outside the cartridge, and an outlet portion configured to emit the light that has entered the container through the inlet portion to the outside of the cartridge, A cover member having a first opening through which the incident surface of the incident portion is exposed, and a second opening through which the exit surface of the exit portion is exposed, and covering a part of the light guide means, Equipped with, When the direction of the optical axis of the incident portion is defined as the direction from the outer surface to the inner surface of the cover member as the first direction, the direction intersecting the first direction and where the incident portion and the exit portion are aligned as the second direction, and the direction intersecting both the first and second directions as the third direction, In a cross-section perpendicular to the third direction, the cover member has a portion of its outer surface that is recessed on the downstream side in the first direction, between the inlet portion and the outlet portion in the second direction. The first end of the bottom surface of the recess on the inlet side in the second direction is located downstream in the first direction from the second end of the bottom surface on the outlet side in the second direction, and The bottom surface is curved such that it is recessed downstream in the first direction with respect to a virtual straight line connecting the first end and the second end, between the first end and the second end. A cartridge characterized by the following features.

3. In the cross-section, the bottom surface of the recess is formed in an arc shape. The center of the arc-shaped bottom surface is located in a position that coincides with the incident portion when viewed in the first direction. The cartridge according to feature 1 or 2.

4. The bottom surface of the recess is formed in a spherical shape. The center of the spherical bottom surface is located in a position that coincides with the incident portion when viewed in the first direction. The cartridge according to feature 1 or 2.

5. The cover member has a protrusion provided between the second end of the bottom surface and the output surface of the light guide means in the second direction, and further has a protrusion that protrudes upstream in the first direction compared to the second end. The cartridge according to feature 1 or 2.

6. The cartridge further comprises a rotating image carrier and a developer carrier that develops an image on the surface of the image carrier using the developer, In the orientation when the cartridge is mounted on the main body of the image forming apparatus, the image carrier is positioned below the light-emitting element of the main body of the apparatus. At least a portion of the cover member is positioned between the light-emitting element and the image carrier in the vertical direction and is arranged to overlap with the image carrier when viewed from above. The cartridge according to feature 1 or 2.

7. The light guiding means further comprises an internal emission surface and an internal incidence surface provided inside the container, and is configured such that the light incident on the incidence surface of the incidence section is emitted from the internal emission surface, passes through the internal space of the container and is incident on the internal incidence surface, and is emitted from the emission surface of the emission section. The inlet and outlet portions are located at the ends of the cartridge in the direction of the rotation axis of the image carrier, The internal ejection surface and the internal injection surface are positioned closer to the center of the cartridge than the injection portion and the ejection portion in the direction of the rotation axis. The cartridge according to feature 6.

8. The main body of the device, A cartridge according to claim 1 or 2, which is attached to the main body of the device, An image forming apparatus comprising, The device body comprises a light-emitting element that emits light, a light-receiving element that receives the light and emits a detection signal, and a substrate having a mounting surface on which the light-emitting element and the light-receiving element are mounted. The first direction is the direction normal to the mounting surface of the substrate, The second direction is parallel to the mounting surface. An image forming apparatus characterized by the following features.

Images