FULL WASTE TONER CONTAINER DETECTOR

Abstract: A full waste toner container detector comprises a piston (36) mounted on a waste toner container (31) for storing waste toner particles (19) collected from the photoreceptor surface, the piston (36) moving responsive to the waste toner pressure in the waste toner container (31), a shutter (12) prov­ ided in the path of light irradiating the photoreceptor so as to close or open the light path, and a wire (35) connected be­ tween the piston and the shutter (12) and forcing the shutter to move in the direction for closing the light path according to the piston (36) movement.

Description: The present invention relates to an excess developer detector which detects when a developer container is full of waste developer collected from an image-bearing member in an electrographic image-recording apparatus. Conventionally, a full waste toner container is detected by a weight sensor, a pressure sensor or an optical sensor provided in the waste toner container. Since the volume and weight of waste toner tend to vary depending upon the waste toner density, however, detection by the weight or pressure sensor is not accurate. Detection by the optical sensor can be also inaccurate when the sensing surface of the sensor is soiled. In addition, the full waste toner container detector using any one of the above sensors incurs high cost. According to the present invention there is provided an assembly for the collection of excess developer material from an image-bearing member in an electrographic image-recording apparatus, the assembly comprising a receptacle for receiving said excess material, a displaceable element arranged to be pushed by the material accumulating in said receptacle and an optical shutter and means for actuating said shutter so as to interrupt light projected onto said image-bearing member in response to displacement of said element. Such an arrangement provides for easy and accurate detection of a full receptacle, and the provision of a shutter for interrupting light projected onto the image-bearing member prevents an image from being copied when the receptacle is full of waste developer. The element is preferably a piston slidably disposed within a cylindrical projection formed in a wall of the receptacle, the piston having a head exposed to contact with material in the receptacle. The actuating means preferably comprises a wire connected between the piston and the shutter, in which case a biasing spring is preferably connected to the shutter at the point of connection of the wire thereto. The assembly is preferably integrally assembled with the image-bearing member as a cartridge which is removable from the body of the electrographic image-recording apparatus. The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein: Fig. 1 is a sectional view of a cartridge including a photoreceptor of a copying machine in which the full waste toner container of an embodiment of the present invention is used; Fig. 2 is a perspective view of the cartridge of Fig. 1; Fig. 3 shows the section of the rear end portion of the waste toner container in the cartridge; and Fig. 4 is a schematic construction drawing of the copying machine. Fig. 4 is a schematic construction drawing of a copying machine related to the present invention. A photoreceptor 1 is mounted, integrally with surrounding electric charger 2, cleaner unit 3, separator unit 4 and light exposure opening (slit) 5, in a housing 6, thus forming a cartridge 7. The cartridge 7 is detachable from the copying machine proper 8. The cartridge 7 can be set in the copying machine proper 8 simply by opening the front panel of the copying machine proper 8 and inserting the cartridge 7 vertical to a copy paper. The cartridge 7 can be dismounted by pulling it to the operator side. A rail guide mechanism (not shown) assists in mounting or dismounting the cartridge 7 in or from the copying machine proper 8. A convergent light transmitter 9 mounted over the light exposure slit 5 and a light source 10 provided to the left of the transmitter 9 constitute an optical system. A document on a manuscript rest 11 is scanned by a light beam from the light source 10 while the manuscript rest 11 is moving horizontally. The light reflected by the document surface passes through the convergent light transmitter 9 for projection onto the photoreceptor 1 which is rotating in the direction of the arrow of Fig. 4. The photoreceptor 1 is uniformly charged by the electric charger 2 before it is exposed to the light coming through the light exposure slit 5. An image is developed by a developing unit 12 and transferred onto a copy paper by a transference charger 13. The copy paper is fed from a copy paper cassette 14 by a paper feed roller 15 mounted at the bottom of the copying machine proper 8. The copy paper, on which the image has been transferred from the photoreceptor 1, is separated from the photoreceptor 1 by the separator unit 4 and conveyed to fixing rollers 16 where the image is fixed on the copy paper. Then, the copy paper is discharged onto a tray 17 which is rotatable about a pin 18 in the direction of the arrow of Fig. 4. For copying operation, the tray 17 which is folded as shown is rotated counterclockwise around the pin 18 and set in the position virtually parallel to the copying machine proper 8. The developing unit 12 has two developing sections either of which is selected by rotation. A shutter 20 is rotatably held by a shutter support plate 19 in the light path between the light exposure slit 5 and the convergent light transmitter 9. As mentioned later, an end of a wire and a spring are connected to the shutter 20. The wire, receiving tension proportional to the waste toner pressure in the container, gives rotation torque to the shutter 20 against the force of the spring. At a certain level of tension applied to the wire, the shutter 20 rotates suddenly, closing the light path between the light exposure slit 5 and the convergent light transmitter 9. Fig. 1 is a sectional view of the cartridge 7. The rotary shaft of the photoreceptor 1, the electric charger 2, the cleaner unit 3 and the separator unit 4 are mounted in the housing 6. The housing 6 has an opening at a portion facing the exposed area "A" of the photoreceptor 1, which opening defines the light exposure slit 5. The shutter support plate 19 is provided above the light exposure slit 5 and supports the shutter 20 to be rotatable. The spring 21 is connected between the housing 6 and an end of the shutter 20. An end of wire is also engaged with the shutter 20 as described later. The cleaner unit 3 comprises a blade 30 for scraping off the toner remaining on the photoreceptor 1 as waste toner, the waste toner container 31, and a rotary plate 32 which rotates to direct the waste toner to the waste toner container 31. Fig. 2 is a perspective view of the rear of the cartridge 7. As shown, the cleaner unit 3 has a projection 33 in its rear end. The projection 33 has a center hole through which a piston 34 is passed. The piston 34 is tapered in its end portion and has a groove 34a in the end. The wire 35 is slidably supported in the groove 34a, with an end connected to the point P1 of the housing 6 and the other end to the point P2. As shown in Fig. 1, the point P2 engaged with the other end of the wire 35 is located in the upper part of the shutter 20 and conforms to the point to which the spring 20 is connected. Fig. 3 shows the section of the projection 33. As shown, the piston 34 is mounted on a slide 36 slidable in the projection 33. In the projection 33, a spring 37 is provided between the slide 36 and the inner wall of the projection 33. The opposite side of the slide 36 is positioned to be in contact with the waste toner 22 in the container 31. As the waste toner pressure in the container 31 increases, the waste toner pressure is applied in the direction of the arrow of Fig. 3 to the slide 36, causing the slide 36 to move toward the left against the force of the spring 37. Operation of the full waste toner container detector is described now. The waste toner pressure is applied in the direction of the arrow of Fig. 3 to the slide 36 according as the amount of the waste toner 22 and therefore its pressure increase. Then, the slide 36 moves toward the left against the force of the spring 37, pushing the piston 34 outwardly. Tension starts being generated in the wire 35 as the piston is projected outwardly. In the normal state as shown in Fig. 1, the shutter 20 is positioned as indicated by solid line, leaving the light path "L" open. When the tension of the wire 35 exceeds a certain level, the shutter 20 is suddenly rotated counterclockwise by the force of the spring 21 and stops at the position indicated by chain double-dashed line in Fig. 1. In this state, since the light path "L" is closed by the shutter 20, light cannot be irradiated on the exposed area "A". As mentioned above, when the pressure of the waste toner 22 in the container 31 exceeds a certain level, the shutter 20 is rotated suddenly by means of the piston 34 and the wire 35, thus closing the light path "L". This operation is achieved regardless of the weight and density of the waste toner in the container 31. Therefore, the light path "L" is closed accurately when the waste toner container 31 is filled up with no room for further waste toner. In the above embodiment of the invention, the spring 21 is connected to the shutter 20, permitting the shutter 20 to close the light path suddenly under the specified condition. The assembly according to the invention may not include the spring 21. According to an embodiment of the present invention in which the piston 34, wire 35 and shutter 20 are integrally mounted in the cartridge 7, when the shutter 20 has closed the light path "L" due to the full waste toner container, the only thing to be done is to replace the cartridge 7 with a new one; the replacement operation is easy enough to be carried out by the user without any help of service staff. According to an embodiment the present invention, since the piston moves responsive to the waste toner pressure in the container, it never happens that the detector determines the container is full when it is not or vice versa. Due to the wire forcing the shutter to move in the direction for closing the light path according to the piston movement, the shutter closes the light path when the waste toner pressure in the container increases to a specified level, that is, when the container has been filled up with waste toner to a certain extent. In other words, the asembly of the present invention inhibits further image forming process when the container has been filled up, preventing waste toner from flowing over the container and soiling the interior of the image forming apparatus. While only certain embodiments of the present invention have been described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the present invention as claimed.

Claims: 1. An assembly for the collection of excess developer material from an image-bearing member in an electrographic image-recording apparatus, the assembly comprising a receptacle (31) for receiving said excess material, a displaceable element (34) arranged to be pushed by the material (22) accumulating in said receptacle and an optical shutter (20) and means for actuating said shutter so as to interrupt light projected onto said image-bearing member in response to displacement of said element. 2. An assembly according to claim 1 wherein said element is a piston slidably disposed within a cylindrical projection (33) formed in a wall of the receptacle, said piston having a head (36) exposed to contact with material in said receptacle. 3. An assembly according to claim 2, wherein said actuating means comprises a wire (35) connected between said piston and said shutter. 4. An assembly as claimed in claim 3, further comprising a biasing spring (21) connected to said shutter at the point of connection of said wire thereto. 5. An assembly as claimed in any one of claims 1 to 4, integrally assembled with said image-bearing member as a cartridge (7) which is removable from the body of said electrographic image-recording apparatus.

Inventors: OGURA, MITSURU, OKADA, KENJI
Applicants: SHARP KABUSHIKI KAISHA
Application year: 1986
Main classification: G03G21
IPC codes: G03G21, G03G15