IMAGE FORMATION APPARATUS

Abstract: An image formation apparatus having an image carrier; first unit (8) comprising at least a cleaning system held on one supporter; and a second unit comprising a developing system to develop electrostatic latent images formed on the image carrier; the said first (8) and second unit which can be mounted to or demounted from the image formation apparatus, a feeding unit to carry the toner used and removed from the said image carrier being provided on the said first unit (8), and a recovery container to recover the used toner carried by the said feeder provided on the said second unit.

Description: This invention relates to an image formation apparatus which includes a development means for developing electrostatic latent images formed on an image carrier and a mechanism to recover waste toner. In image formation equipment such as electronic photocopying equipment, an electrostatic latent image is formed on a photosensitive image carrier and this latent image is developed by a developer. The toner used for this developing method has generally been black. Recently, however, there has been an increase in the use of mono-color developing where red, blue and other toners can be selected by changing over a developing unit for installation in the main body of the equipment. However, a compact image forming unit including a developing system has not been produced. JP-A-60-143360 discloses a process kit for an image forming device, the process kit being divided into first and second kits which lock together and which are attached to and detached from the device main body whilst so united. Each kit includes consumption members which have corresponding lives; for example one kit includes a developing device and a cleaner, while the other kit includes an image carrier. The present invention aims to allow the size of a unit which includes the developing equipment to be reduced irrespective of the life of the image carrier by configuring the image forming apparatus with a first unit including an image carrier and a second unit including a developer and waste toner recovery container. The intention of the present invention is to provide for easy replacement of the developing unit and discarding of the waste toner by just replacing said second unit including the developer. According to the present invention there is provided an image forming apparatus comprising: (a) a first unit containing an image carrier and a cleaning system to remove toner from said image carrier, (b) a second unit containing a development means to develop electrostatic latent images formed on said image carrier, said first and second units being so mounted on the body of the apparatus that an operator may easily detach them therefrom or mount them thereto, and (c) a feeder to carry toner from the cleaning system to a waste toner recovery container provided in said second unit. A preferred embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:- Fig. 1 is a schematic side sectional view of an electrophotographic copying machine in accordance with the present invention; Fig. 2 is a general perspective view of a second unit which includes a development means; Fig. 3 is a general perspective view of a first unit which includes a photosensitive image carrier; Fig. 4 is a perspective view of the copying machine with no second unit installed; and Fig. 5 is a perspective view of the copying machine with the second unit installed. With reference to Fig. 1 a drum-shaped photosensitive device 2 for carrying a copy image is mounted at the approximate centre of the copying machine 1. The photosensitive device 2 is mounted for rotation by a drive mechanism, not shown. Around the photosensitive device 2, a charger 3, a light focuser/transmitter 4, a development means 5, a transfer station 6, and a cleaner 7 are arranged in succession in the rotating direction of the photosensitive device for formation of a copy image. In this copying machine 1, at least the photosensitive device 2, charger 3 and cleaner 7 are held in a common case to configure a first unit 8. This first unit 8 is held by a guide supporter, not shown, provided on the main body of the copying machine and can be easily detached or remounted by the operator by using a mounting handle provided on the unit. An original support 9 which is used to set the original and expose it with the exposure light source 10 is movably mounted on the copying machine 1. This original support 9 is scanned in the lateral direction by a drive unit, not shown. The optical image obtained by the irradiation of the original with the exposure light source 10 is projected onto the photoconductive layer on the surface of the photosensitive device 2 by the light focuser/transmitter 4. An electrostatic latent image is thereby formed on the photosensitive device 2 corresponding to the image of the original and this latent image is visualised by the development means 5, which is in a second unit 15. Then, the image visualised by the said development means 5 (ie. the toner image) is transferred at the transfer station onto the transfer paper which is carried from the paper feeder at the proper time. At this time, about 20% of the toner remains on the surface of the drum of the photosensitive device 2. In order to remove this toner to prepare the drum for the next image forming process, a cleaner 7 is provided. This cleaner 7 comprises an elastic cleaning blade 70 pushed into contact with the surface of the photosensitive device 2 to scrape off the remaining toner. The toner scraped off with the cleaning blade 70 is received by a waste toner receiver 7a positioned under the cleaning blade. At the position of this waste toner receiver 7a there is provided a rotatable waste toner feeder 7b. The waste toner feeder 7b carries the toner which has dropped to the waste toner receiver 7a in the direction of the rotating axis of the photosensitive device to one side of the first unit. On this one side there is provided a feeder 7c which cooperates with the feeder 7b to carry the toner fed by the latter in a new carrying direction which, as can be seen from Fig. 3, makes a right angle to the previous carrying direction. This feeder 7c faces a waste toner recovery container 56 which is provided in the second unit with the development means 5, described more fully later. More particularly, the outlet port provided in the feeder 7c and the opening of the waste toner recover container 56 are positioned to face each other. On the other hand, the transfer paper which has been sent to the transfer station position is separated from the surface of the drum of the photosensitive device 2 by a separator 11 after the transfer of the image, and is then sent along a feeding guide 12 to an overheat fixer 13. In the fixer 13, the toner powder image on the transfer paper is fixed by heat and pressure and the transfer paper is discharged after fixing to the paper discharger 14. Fig. 2 is a general perspective view of the second unit 15 consisting of the development means 5 and the waste toner recovery container 56. When the second unit is mounted to the main body of the copying machine, a cover 51 over the developing opening is moved so as to expose a magnetic brush of the toner formed on a developing sleeve; the second unit is mounted to its mounting position in the main body of the copying machine by the operator holding the second unit mounting handle 52. Numeral 54 indicates a positioning boss to be locked to a positioning hole 8a provided on the side of the first unit 8 and numeral 53 indicates a locking claw for holding the development means 5 when it is installed to the main body of the copying machine. A marking 55 indicates the color of the toner in the case of mono-color copying and can be seen through an indicating window 1b formed in the front cabinet wall 1a. Numeral 56 indicates a container held in the second unit with the development means 5 for recovering waste toner which is carried from the first unit. Thus, the container 56 and development means 5 are replaced at the same time. Numeral 57 is a cover for a waste toner receiving port, this cover 57 being opened in the direction of the arrow when the second unit is mounted. The cover 57 prevents the waste toner from overflowing when the second unit is detached. It is designed so that, when the above-described cover 57 is opened, the waste toner receiving port becomes coincident with the discharge port of the feeder 7c of the first unit. Fig. 3 is a general perspective view of the first unit 8 to be demounted from, or remounted to the main body of the copying machine. As described above, the first unit 8 includes in a common case a photosensitive drum and a cleaner 7 to remove toner remaining on the surface of the photosensitive drum. The waste toner removed from the surface of the photosensitive drum 2 by the cleaner 7 is carried to the one side of the first unit by the feeder 7b, and then discharged from the discharge port by the feeder 7c. This feeder 7c is provided with a cover 7d which moves in the direction of the arrow to open or close the discharge port. When the waste toner recovery container 56 provided in the second unit reaches a specified position during mounting of the second unit, the cover 7d is opened thereby opening the discharge port. The discharge port of the feeder 7c is provided so as to be coincident with the waste toner receiving port of the waste toner recovery container 56 of the second unit. The second unit cannot be installed unless the first unit 8 is installed to the main body of the copying machine. When the first unit 8 is installed to the main body of the equipment, a guide for the second unit is configured. For this purpose, the first unit 8 is provided with a guide 8b as shown in Fig. 3. This guide 8b provided on the first unit 8 not only guides the second unit, but also serves together with the positioning boss 54 provided in the second unit, to position the developing magnetic brush precisely relative to the photosensitive surface of the drum. Fig. 4 shows the copying machine in its condition with the said first unit mounted. The mounting procedure for the second unit is described below. The first unit 8 is mounted to the main body of the copying machine 1. The second unit is inserted to the main body of the copying machine with its bottom part advancing along the guide 1c formed by a part of the frame of the main body of the copying machine. Thus the second unit is led inwardly by the guide 8b provided in the first unit 8 and becomes connected to the image unit driver, not shown, in the inner part of the main body of the copying machine. At the same time, the positioning boss 54 of the second unit is fitted to the positioning hole 8a of the first unit 8. To lock the second unit in place the locking claw 53 provided on the second unit is hitched to the catch 1d of the guide 1c of the frame of the main body of the copying machine. Upon the completion of the mounting of the second unit, the covers 7d and 57 provided respectively at the discharge port of the feeder 7c in the first unit to carry the waste toner and the waste toner receiving port of the waste toner recovery container 56 are both opened so that passage of waste toner through the aligned discharge port and receiving port to the recovery container 56 becomes possible. Fig. 5 shows the condition where the second unit is installed. By the above configuration, the second unit is properly positioned relative to the first unit 8, and, while the main body of the copying machine is working, the toner remaining on the photosensitive device 2 is carried by each feeder and recovered to the recovery container 56 held in the second unit. When the life of the second unit including the development means 5 has expired, for instance, when the fresh toner supply of the development means 5 has been exhausted, only the second unit needs to be replaced. Therefore it is not necessary to increase the volume of the second unit including the development means 5 to match the life of the photosensitive device 2 in the first unit 8. Therefore, the second unit need not correspond in lifetime to the first unit and can be small. The recovery container 56 has no relation with the first unit 8 either and therefore its size can be freely determined. It is advisable to determine the size of the waste toner recovery container 56 based on the capacity of the fresh toner supply in the development means 5. For instance, the capacity may be determined so that this fresh toner supply of the development means 5 of the second unit is exhausted and the second unit needs to be replaced before the life of the photosensitive device 2 has expired and so that the waste toner recovery container becomes almost filled with waste toner when the second unit needs to be replaced. In other words, the size of the recovery container 56 may be determined so that the recovery container 56 is almost filled with waste toner when the first unit is replaced. Therefore, the service life does not have to be considered when the second and first unit are replaced. Especially, the first unit can be designed freely and can be small. Thus, in the above-described system according to this invention, when the fresh toner supply has been exhausted and the unit with the development means is replaced, the waste toner recovery container is also replaced and therefore replacement is performed quickly and easily. The assembly of image forming components is divided into two units which have extremely different lives and as a result, each unit can be used effectively until its life has expired and can be small. 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: Image forming apparatus comprising: (a) a first unit (8) containing an image carrier (2) and a cleaning system (7) to remove toner from said image carrier, (b) a second unit (15) containing a development means (5) to develop electrostatic latent images formed on said image carrier, said first and second units being so mounted on the body of the apparatus that an operator may easily detach them therefrom or mount them thereto, and (c) a feeder (7b,7c) to carry toner from the cleaning system (7) to a waste toner recovery container (56) provided in said second unit (15). Image forming apparatus according to claim 1, wherein said feeder comprises a rotary feeder means (7b) which initially feeds the waste toner within said first unit (8) to an end thereof in a direction parallel to the rotary axis of a photosensitive drum which constitutes said image carrier. Image forming apparatus according to claim 2 wherein said feeder comprises a further feeder means (7c) which feeds the waste toner arriving at said end of said first unit in a direction at right angles to the direction of toner feed of said rotary feeder means toward said waste toner recovery container (56). Image forming apparatus according to any of claims 1 to 3, wherein said feeder feeds the waste toner to an opening of said waste toner recovery container (56). Image forming apparatus according to any preceding claim, wherein the first and second units (8, 15) are constructed such that said first unit must be positioned within the body of the image forming apparatus before said second unit can be positioned within said body of said image forming apparatus. Image forming apparatus according to claim 5, wherein said first unit includes a guide means (8a, 8b) by which said second unit (15) is positioned within the body of said image forming apparatus. Image forming apparatus according to any preceding claim wherein the capacity of the waste toner recovery container (56) is such as to allow replacement, after expiry of its life, independently from the replacement of the image carrier, after expiry of the image carrier's life. Image forming apparatus according to any of claims 1 to 6 wherein the capacity of the fresh toner supply in the development means (5) is such as to allow replacement, after expiry of its life, independently from the replacement of the image carrier, after expiry of the image carrier's life. Image forming apparatus according to any preceding claim wherein the capacity of the waste toner recovery container (56) substantially corresponds with the volume of waste toner fed from said first unit throughout the life of the fresh toner supply in the development means (5), so that the waste toner recovery container (56) is substantially filled when said fresh toner supply is exhausted. Image forming apparatus according to any preceding claim wherein the waste toner recovery container has a waste toner receiving port arranged to be automatically closed by a cover (57), when the second unit is detached from the body of the apparatus, and is arranged to be automatically opened, when the second unit is mounted thereto. Image forming apparatus according to any preceding claim, wherein the feeder is in the first unit and has a waste toner discharge port and a cover (7d) which is arranged to automatically close the opening when the second unit is detached from the body of the apparatus, and is arranged to open said port when the second unit is mounted thereto, thereby communicating the feeder (7c) to the waste toner recovery container (56).

Inventors: KATOH, ITSURO, YOSHIURA, SHOICHIRO
Applicants: SHARP KABUSHIKI KAISHA
Application year: 1987
Main classification: G03G15
IPC codes: G03G21