WASTE TONER COLLECTING SYSTEM

Abstract: A waste toner collecting system in an image forming equipment which forms on the surface of an image carrier an electrostatic latent image corresponding to an original image, visualizes the latent image with toner and transferrs the toner image onto a copying material. The waste toner collecting system comprises a cleaning unit for removing residual toner on the image carrier after the toner image has been transferred, a container, indepen­ dent of the cleaning unit, for storing the removed waste toner, a transport device for conveying the waste toner removed by the cleaning unit to the container, an outlet formed in the toner transport device so as to discharge the waste toner, a waste to­ ner inlet formed in the container at the position corresponding to the outlet in the toner transport device, and shutter members provided for the outlet and the inlet, respectively, the shutter members being opened or closed according as the container is mounted or dismounted.

Description: The present invention relates to a system for use in image forming equipment for collecting in a waste toner container the residual waste toner removed from the surface of an image carrier after an electrostatic latent image formed on the image carrier is visualized with toner and transferred onto a copying material. An image forming equipment such as an electro-photographic copying machine forms an electrostatic latent image on a photoreceptor as an image carrier and visualizes the latent image by a developing unit. After the image visualized with toner is transferred onto a copying material, the residual toner on the image carrier is removed by cleaning means such as a cleaning blade. The waste toner thus removed is conveyed by transport means such as a screw to the exterior of the cleaning unit installed in the copying machine, and collected in a waste toner container positioned facing an outlet formed in the end portion of the transport means. With the above construction, it is easy to dismount the container for repair, maintenance or replacement when the container is full of waste toner. However, in disconnecting the waste toner container from the outlet of the transport means of the cleaning unit, waste toner tends to drop in the copying machine through the outlet, soiling the machine interior, which is a disadvantage of the conventional copying machine. European Patent Application EP-A-0248682, which was published after the priority date of the present application, describes an image formation apparatus of the above general type wherein there is provided a container for storing removed waste toner and a cover on the container which is opened when the container is mounted adjacent a waste toner carrier; the carrier is also provided with a cover which is opened at the same time as the cover on the container is opened. It would be desirable to provide a waste toner collecting system for removing residual toner on an image carrier by cleaning means and transporting the removed waste toner to a waste toner container, which system prevents the waste toner from dropping through the outlet of the transport means or through the inlet of the waste toner container when the container is dismounted, so as not to soil the copy machine interior, in an arrangement which provides an improvement over the above-mentioned prior-art system. SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a waste toner collecting system for use in an image forming apparatus which forms a latent image on an image carrier and develops the latent image using toner material, said system comprising: means for removing residual toner from said image carrier and for conveying said residual toner to an outlet to discharge the waste toner; a container for storing the removed waste toner; a waste toner inlet formed in said container at a position corresponding to said outlet; an inlet shutter member for said inlet; means for automatically opening and closing said inlet shutter member in response to said container being mounted and dismounted respectively; an outlet shutter member for said outlet; and means for automatically opening and closing said outlet shutter member in response to said container being mounted and dismounted respectively; wherein said inlet shutter member is arranged to be opened prior to said outlet shutter member when the container is being mounted and said outlet shutter member is arranged to be closed prior to said inlet shutter member when the container is being dismounted. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given thereinbelow 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 schematic sectional side elevation of an electro-photographic copying machine related to the present invention; Fig. 2 is a perspective view of a second image forming unit; Fig. 3 is a perspective view of a first image forming unit; Fig. 4 is a perspective view of the copying machine without the second image forming unit mounted; Fig. 5 is another perspective view of the copying machine in which both of the first and the second image forming units are mounted; Figs. 6(A) through 6(C) show a slidable cover provided on the waste toner container, explaining how the shielding member of the slidable cover is opened; and Fig. 7 is a plan view of a slidable cover provided on the transport means conveying waste toner to be discharged through the outlet. DESCRIPTION OF THE PREFERRED EMBODIMENT Fig. 1 is a schematic sectional side elevation of the electro-photographic copying machine related to the present invention. In the approximate center of the copying machine 1 is mounted a drum-shaped photoreceptor 2 for forming thereon a latent image. The photoreceptor 2 is held by a driving mechanism (not shown) in such a manner that it is rotatable clockwise. An electric charger 3, a convergent light transmitter 4, a developing unit 5, a transfer unit 6 and a cleaning unit 7 are arranged in this order in the rotary direction around the photoreceptor 2. The photoreceptor 2, the electric charger 3 and the cleaning unit 7 are retained in at least one housing, constituting a first image forming unit 8. The first image forming unit 8 is set on guide support means (not shown) formed in the copying machine so that it is easily dismounted from or mounted in the copying machine by the handle on the unit 8. An original platen 9 is movably provided on top of the copying machine 1. An original is placed on the original platen 9 to be exposed to an exposure light 10. The original platen 9 is laterally moved by a driving unit (not shown) for scanning. An optical image obtained by irradiating the original with the exposure light 10 is projected through the convergent light transmitter 4 onto the photoconductive layer on the surface of the photoreceptor 2, whereby an electrostatic latent image corresponding to the original image is formed on the surface of the photoreceptor 2. The latent image is visualized by the developing unit 5 which constitutes a second image forming unit. The image visualized by the developing unit 5 (toner image) is transferred by the transfer unit 6 onto a copying paper which is sent from the paper feeder in a timely manner. Twenty percent of the toner is left on the photoreceptor surface. This residual toner must be removed to make the photoreceptor 2 ready for the subsequent copying operation. The cleaning unit 7 is provided for this purpose. The cleaning unit 7 contains an elastic cleaning blade 70 which is pressed against the surface of the photoreceptor 2 so as to scrape the residual toner off the rotating photoreceptor 2. The residual toner thus removed by the cleaning blade 70 drops on waste toner receiver means 7a located under the cleaning blade 70. Waste toner transport means 7b is rotatably provided at the position of the waste toner receiver means 7a, so that the transport means 7b conveys the waste toner dropped on the receiver means 7a in the same dirction as the rotation of the photoreceptor 2 to a side portion of the first image forming unit. As shown in Fig. 3, a transport unit 7c containing a spiral transport means is provided at the side portion, communicating with the waste toner transport means 7b, so that the waste toner is conveyed by the transport unit 7c in the direction vertical to the transportation by the waste toner transport means 7b. The transport unit 7c faces a waste toner container 56 (described later) mounted integrally with the developing unit 5. More specifically, an outlet 72 (Fig. 7) formed in the transport unit 7c faces an inlet formed in the waste toner container 56. Meanwhile, the copying paper, to which the toner image is transferred at the transfer position, is peeled off the photoreceptor 2 by a separator unit 11 and sent along a carriage guide 12 to a thermal fixing device 13 where the toner image is fixed on the copying paper by using heat and pressure. Then, the copying paper with the image fixed thereon is transported to a discharge tray 14. Fig. 2 is a perspective view of the entire second image forming unit comprising the developing unit 5 and the waste toner container 56. Prior to mounting the second image forming unit, a cover 51 over the developing opening must be removed to expose a magnetic toner brush provided on a developing sleeve. The second image forming unit is mounted in the specified place in the copying machine by a handle 52. 54 is a positioning boss to be locked in a positioning hole 8a (Fig. 4) formed in the first image forming unit 8. 53 is a locking craw which secures the developing unit 5 to the copying machine 1. 55 is a color indicator which tells the operator the toner color in the mono-color copying operation. The color indicator 55 can be viewed through a window 1b provided in a front cabinet 1a of the copying machine. 56 is the waste toner container which stores waste toner sent from the first image forming unit 8. The container 56 is held integrally with the developing unit 5 so that they can be replaced at the same time. 57 is a slidable cover which provides a shutter mechanism for the waste toner inlet 58 (Fig. 6). When the second image forming unit is mounted in the copying machine, the slidable cover 57 moves in the direction indicated by the arrow to open the waste toner inlet 58. When the second image forming unit is dismounted from the copying machine, the slidable cover 57 closes the waste toner inlet 58, preventing the waste toner from dropping out of the second image forming unit. The position of the waste toner inlet 58 is such that it meets the outlet 72 (See Fig. 7.) in the transport unit 7c of the first image forming unit when both of the first and the second image forming unit are mounted. Now, the opening mechanism of the slidable cover 57 is described in detail below. As shown in Fig. 6, the slidable cover 57 is mounted at the position corresponding to the inlet 58 of the waste toner container 56 and is slidable on the container 56 by means of guide members. The slidable cover 57 has a cutaway portion 59 corresponding to the waste toner inlet 58. A spring 60 is provided between the cover 57 and the container 56 so that the cover 57 is forced to close the inlet 58 at all times. A slide hole 61 is formed in the slidable cover 57, enabling the slidable cover 57 to move in the direction opposite from the spring 60, thereby opening the inlet 58 of the waste toner container 56. A guide groove 62 for guiding a movable pin 63 is formed obliquely in the container 56 to correspond with the hole 61. The movable pin 63 is guided with its one end sliding in the guide groove 62 and with the other end sliding in the hole 61. The movable pin 63 is fixed to an end portion of an arm member 64 provided between the container 56 and the slidable cover 57. On the other end of the arm member 64 is fixed a fulcrum pin 65 which fits in a slit 66 formed in the waste toner container 56. The fulcrum pin 65 ensures the stable movement of the movable pin in the guide groove 62. The slit 66 helps the movable pin 63 move in the guide groove 62. When the movable pin 63 is pressed down along the slide hole 61, the movable pin 63 moves down in the slide hole 61 and simultaneously in the guide groove 62 as well, causing the slidable cover 57 to move against the force of the spring 60. Thus, the waste toner inlet 58 is exposed as the cutaway portion 59 of the slidable cover 57 coincides with the inlet 58. When the movable pin 63 is released, the slidable cover 57 moves in the direction for closing the inlet 58 due to the force of the spring 60. The slidable cover 57 has a projection 67 which works to open another slidable cover 71 provided on the outlet 72 of the transport unit 7c. Fig. 3 is a perspective view of the entire first image forming unit 8 which can be removably mounted in the copying machine. As mentioned earlier, the first image forming unit 8 comprises the photoreceptor 2 and the cleaning unit 7 accommodated in at least one housing. Waste toner scraped off the photoreceptor surface by the cleaning unit 7 is carried by the transport means 7b to the side portion of the first image forming unit 8 and then by the transport unit 7c and discharged through the outlet 72 of the transport unit 7c. The transport unit 7c is equipped with the cover 71 slidable in the direction of the arrow to open the outlet 72. When the second image forming unit is set in its proper position in the copying machine, the slidable cover 57 on the waste toner container 56 in the second unit is moved to open the inlet 58, and then the slidable cover 71 is moved to open the outlet 72. The outlet 72 of the transport unit 7c is located to meet the inlet 58 of the waste toner container 56 in the second image forming unit. The cover 71 is, as shown in Fig. 7, slidable in guide means 73 so as to open or close the outlet 72 of the transport unit 7c. The slidable cover 71 has an opening 74 for the outlet 72. A spring 75 is provided between the slidable cover 71 and the transport unit 7c so that the outlet 72 is normally closed by the cover 71. The slidable cover 71 is maintained at the position shown in Fig. 7 due to a stopper (not shown). A protrusion 76 is formed integrally with the transport unit 7c at the position corresponding to the movable pin 63 which moves the slidable cover 57 to open. The slidable cover 71 has a projection 77 at the position corresponding with the projection 67 on the slidable cover 57. When the slidable cover 57 on the waste toner container 56 opens, the projection 67 engages the projection 77 on the slidable cover 71. Here, it must be noted that the second image forming unit can not be mounted in the copying machine prior to the first image forming unit 8. This is because guideway means for mounting the second image forming unit is not formed until the first image forming unit 8 has been set in its place. As the guideway means, the first image forming unit 8 is provided with a guide 8b shown in Fig. 4. The guide 8b not only leads the second image forming unit to its proper position but also serves to position the magnetic toner brush accurately in relation to the photoreceptor 2 together with the positioning boss 54 on the second image forming unit. Fig. 4 shows the copying machine in which the first image forming unit 8 is mounted. The procedure of mounting the second image forming unit is as follows. It is assumed that the first image forming unit 8 has been set in the copying machine 1. The second image forming unit is inserted in the copying machine 1 with the bottom of the unit sliding along a guideway 1c comprising a part of the frame of the copying machine. The second image forming unit is led by the guide 8b formed on the first image forming unit 8 into the copying machine where it is coupled with the driving means (not shown) of the developing unit. Simultaneously, the positioning boss 54 of the second image forming unit is fit and locked in the positioning hole 8a of the first image forming unit 8. The second image forming unit, if left as it is, might come off the copying machine because it is not restricted in its movement in the insertion direction. To prevent the unit from coming off, the locking craw 53 of the second image forming unit is made engaged with an edge 1d of the guide 1c on the copying machine frame. When the second image forming unit has been mounted, the slidable cover 71 on the transport unit 7c of the first image forming unit 8 and the slidable cover 57 on the waste toner container 56 of the second image forming unit are moved to open the outlet 72 and the inlet 58, respectively, so that the transport unit 7c communicates with the waste toner container 56, permitting waste toner to be led in the container 56. Fig. 5 shows the copying machine in which the two image forming units are mounted. The second image forming unit is thus positioned accurately with respect to the first image forming unit 8. Residual waste toner removed from the photoreceptor 2 is carried by the aforementioned various conveyance means and collected in the waste toner container 56 in the second image forming unit as long as the copying machine is operated. When the service life of the second image forming unit including the developing unit 5 has expired, or when toner in the developing unit 5 has been used up, for instance, the operator is required to replace only the second image forming unit. By doing so, the waste toner container 56 held integrally with the second image forming unit can be replaced simultaneously. According to the present invention, therefore, the replacement procedures are very simple. Figs. 6(A) through 6(C) explain how the slidable cover on the waste toner container is opened by mounting the second image forming unit. Fig. 6(A) shows the state of the slidable cover on the waste toner container of the second image forming unit when the unit is about to be mounted. In this state, the slidable cover 57 is held by the spring 60 to close the inlet 58. As the unit is being inserted, the movable pin 63 on the waste toner container 56 comes in contact with the protrusion 76 formed on the transport unit 7c of the first image forming unit 8. In Fig. 6(B), the protrusion 76 of the first image forming unit 8 is pressing the movable pin 63 of the container 56 whereby the slidable cover 57 starts opening. Supported by the arm member 64 rotatable about the fulcrum pin 65 fit in the slit 66, the movable pin 63 moves in the guide groove 62 on the waste toner container 56 as well as in the slide hole 61 in the slidable cover 57. Eventually, the cutaway portion 59 meets the inlet 58, exposing the inlet 58. In Fig. 6(C), the mounting of the second image forming unit is almost completed so that the inlet 58 is completely open. The movable pin 63 is now located on the side of the protrusion 76 of the first image forming unit 8, retaining the slidable cover 57 in its open position. In this state, the projection 67 on the slidable cover 57 comes in touch with the projection 77 on the slidable cover 71 provided at the end of the transport unit of the first image forming unit 8. When the second image forming unit (or the waste toner container 56) is further inserted to its specified position, the slidable cover 71 is pressed by the projection 67 and moved against the force of the spring 75. Finally, the outlet 72 is exposed when the opening 74 coincides with the outlet 72. Meanwhile, the slidable cover 57 is maintained at the same position while the slidable cover 71 is being opened, because the movable pin 63 moves only along the side of the protrusion 76. When the second image forming unit is dismounted, in contrast, the waste toner outlet 72 of the first image forming unit 8 is first closed by the slidable cover 71 due to the spring force before the inlet 57 of the container 56 is closed by the slidable cover 57. In the above embodiment, as understood, the waste toner container 56 is mounted integrally with the developing unit so that the container 56 is replaced together with the developing unit. Alternatively, the waste toner container 56 may be designed to be removable from the developing unit, enabling the container 56 alone to be replaced. In this case, the slidable covers 57 and 71 are operated according as the container 56 is mounted or dismounted. Specifically, the slidable cover 57 opens prior to the slidable cover 71 when the waste toner container 56 is mounted. The slidable covers 57 and 71 constituting the shutter members need not be always operated mechanically as in the above embodiment, provided that they are operated in relation to the replacement operation of the waste toner container 56. The slidable covers 57 and 71 may be operated by using solenoids. In this case, the solenoids must be controlled on the basis of detection whether or not the container 56 is mounted. As appreciated from the above, according to the present invention, waste toner remaining on the image carrier is removed by the cleaning means and transported by the conveyance means to the waste toner container. The slidable shutter members provided on the outlet of the conveyance means and on the inlet of the waste toner container, respectively, are opened or closed according as the waste toner container is mounted or dismounted. Consequently, the prevent invention prevents waste toner from dropping and soiling the interior and the surrounding of the copying machine when the container is mounted or dismounted. 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: A waste toner collecting system for use in an image forming apparatus (8) which forms a latent image on an image carrier (2) and develops the latent image using toner material, said system comprising: means (70,7b) for removing residual toner from said image carrier and for conveying said residual toner to an outlet (72) to discharge the waste toner; a container (56) for storing the removed waste toner; a waste toner inlet (58) formed in said container at a position corresponding to said outlet; an inlet shutter member (57) for said inlet (58); means (63,76) for automatically opening and closing said inlet shutter member in response to said container being mounted and dismounted respectively; an outlet shutter member (71) for said outlet (72); and means (67,77) for automatically opening and closing said outlet shutter member in response to said container being mounted and dismounted respectively; wherein said inlet shutter member (57) is arranged to be opened prior to said outlet shutter member (71) when the container is being mounted and said outlet shutter member (71) is arranged to be closed prior to said inlet shutter member (57) when the container is being dismounted.

Inventors: FUKUNAGA, TAKAHIRO, HAGIHARA, HIDEAKI, TAKAHASHI, KOZO, YOSHIURA, SHOICHIRO
Applicants: SHARP KABUSHIKI KAISHA
Application year: 1987
Main classification: G03G21
IPC codes: G03G21