Color image forming apparatus

Abstract: The invention provides an apparatus for forming a color toner image on a photoreceptor belt. The photoreceptor belt is stretched to form a loop around a plurality of rollers and installed in a cartridge which is made to be detachable from the apparatus. The cartridge is made to additionally house a container for collecting residual toner removed from the photoreceptor belt or a toner supply unit for supplying toner to a plurality of developing devices.

Description: BACKGROUND OF THE INVENTION The present invention relates to a color image forming apparatus in which a toner image can be formed on a belt-like image forming body in an electrophotographic way and transferred to a transfer material to reproduce an image. There have been many prior disclosures about reproduction of a color image. The apparatus of the type, for example, in Japanese Patent O.P.I. (Open to Public Inspection) No. 100770/1986 can obtain a color copy in a way that a latent image is formed and developed on a photosensitive drum which is an image forming body according to a number of color separation from an original, is transferred onto a transfer drum to form a multi-color image upon every development, and is transferred to a sheet of recording paper. In addition to the photosensitive drum, the apparatus of the type described needs the additional transfer drum of a size on which one sheet of image can be transferred. It is therefore unavoidable to make the apparatus large size and complicated. The apparatus of another type, for example, in Japanese Patent O.P.I (Open to Public Inspection) No. 14992/1986 can obtain a multi-color copy in a way that a latent image is formed and developed on a photosensitive drum according to a number of color separations from an original, and is transferred onto a transfer material upon every development. In the apparatus of the type described, however, it is difficult to precisely overlap a number of color image components to obtain a quality color copy. The apparatuses of another type proposed by the applicant in Japanese Patent Application O.P.I. Nos. 75850/1985, 76766/1985, 95456/1985, 95458/1985 and 158475/1985 can obtain a color image in a basic multi-color image forming process that latent image formation and color toner development are repeated a number of times equal to the number of color image separations on a photosensitive drum, the color toner images are overlapped on the photosensitive drum, and transfer is made. In the multi-color image forming apparatuses of the type described in which the overlapping method is used, a plurality of developing means for different colors are provided around the photosensitive drum which usually has to be revolved a multiple number of times to develop the latent image thereon to produce the color image. As the image forming body, there was proposed the photosensitive drum mentioned above with a photoconductive material coated or evaporated on an outside thereof. There also was proposed a belt-like image forming body with the photoconductive material coated or attached on a flexible belt. The beltlike image forming body (hereinafter referred to as the photosensitive belt) is effective to make use of possible space because its shape can be determined by the photosensitive belt provided between revolving rollers including a drive roller. This allows the color image forming apparatus to be made compact. The photosensitive belt can be run along a small curvature with use of the revolving roller of a small diameter. The small curvature portion can be used to separate a transferring material. This prevents insufficient separation of the transferring material. The photosensitive drum of another type proposed, for example, in Japanese Patent Application O.P.I. No. 48350/1988 is made in the way that the photosensitive drum can collect used toner therein. Also, the used toner collecting container of a type proposed, for example, in Japanese Patent Application O.P.I. No. 150782/1981 can be employed in view of the amount of used toner in a photosensitive drum and photosensitive paper wrapped on it. These proposals aim at making the apparatus small size and compact. However, in both the used toner collecting apparatuses, the types and materials of the photosensitive drums are related to service life of the apparatuses. Particularly, a toner carrying mechanism for carrying the toner to a revolving drum body is complicated, being defective in leakage and splashing of the toner. The used toner collecting apparatuses cannot always be made compact at low costs. The color image forming apparatus using the photosensitive belt described previously has image forming means, including an electricity charging means, an image exposing means, a plurality of developing means, and cleaning means, provided to face primarily a lower outside of the photosensitive belt. These image forming means are integrated together with the photosensitive belt to be a single module as a process cartridge so that it can be independently attached to or detached from the main body. Accordingly, a toner supply container for containing the toner to supply the developing means and a closed used toner container for containing the used toner collected by the cleaning device, have to be provided at positions where they can be functionally coupled with the process cartridge. It is however difficult to integrate them with the developing means and cleaning device in view of different service lives and maintenance service work. US-4,791,454 discloses an image forming device in which a detachable cartridge houses the photoconductive belt, cleaning device and toner collecting container. It is a first object of the present invention to provide a colour image forming apparatus in which a toner supply container and a closed used toner container can be easily attached to or detached from a process cartridge as necessary. If many image forming means are integrated to a single module, the cartridge is made large and heavy. It is not only difficult to attach to or detach from the main body, but also inconvenient in connection with maintenance service as every image forming means are different in the service lives and maintenance frequency. Accordingly, it is a second object of the present invention to propose a colour image forming apparatus in which the image forming means such as the photosensitive belt can be attached to or detached from the main body in a very easy way so that they will not interfere each other with respect to maintenance and checking. Other objects of the invention or preferred aspects thereof will become clear. According to the present invention there is provided a colour image forming apparatus, comprising: a photoreceptor belt for forming a latent image thereon, the photoreceptor belt stretched to form a loop around plural pieces of rotatable rollers; a cartridge, adapted to be detachable from the apparatus, for housing the photoreceptor belt; and a plurality of developing means for developing the latent image on the photoreceptor belt so as to form a colour toner image, characterised in that: the plurality of developing means are disposed inside the cartridge so as to face the photoreceptor belt; and by a toner supply unit including a plurality of toner containers for supplying toner to the plurality of developing means, the toner supplying unit being detachably mounted on the cartridge. In the abovementioned apparatus, to make the apparatus fully effectively utilize a space in the used toner container in order to correct the used toner smoothly in any time, the cartridge can be provided with a handle at one side thereof, and the used toner container is provided with an inlet for correcting the used toner at a side corresponding to the one side of the cartridge. The used toner recovery efficiency into the used toner container is improved by providing a toner distribution means for evenly distributing the used toner in the container. These and other objects and features of this invention will be better understood upon consideration of the following detailed description and the accompanying drawings in which: Figs. 1 and 4 show cross-sectional illustrative views of a first embodiment of a color image forming apparatus according to the present invention. Fig. 2 is a block diagram illustrating an image forming system. Figs. 3 and 5 are cross-sectional illustrative front and rear views of the cartridge accommodated in the apparatus, respectively. Fig. 6 shows cross-sectional illustrative views of major parts of the cartridge. Figs. 7 and 8 are detailed views of a toner distribution uniforming means of a used toner collecting container. A preferred embodiment of the color image forming apparatus according to the present invention is shown in Figs. 1 through 6. In Fig. 1, a flexible photosensitive belt 1 can form an image. The photosensitive belt 1 which is fitted on revolving rollers 2 and 3 is moved by the revolving roller 2 clockwise. The photosensitive belt 1 is made to tense to slide on a guide member 4 with an inside thereof by an action of a tension roller 5. Photoconductor layer on an outside of the photosensitive belt 1 therefore can be kept at a certain distance from an outside of the guide member 4 during carrying motion. This provides a stable image forming surface. An electric charger 6 is a scorotron charger, a laser writing unit 7 is an image exposing means, and a plurality of developing means 8 through 11 contain developing agents of specific colors. These image forming means are faced with the photosensitive belt 1 on the guide member 4. The photosensitive belt 1 is fitted to the guide member 4 by means of gap forming means pressing the outside thereof so that a gap can be kept between the photosensitive belt 1 and the developing arrangements 8 through 11 not to disturbe the moving of the photosensitive belt 1. Instead of the laser writing unit 7, an optical system in which an light emitting section and a fibre lens array are integrated can be used in place of the optical system shown. Each of the developing means 8, 9, 10, and 11 can contain the developing agents of specific colors, such as yellow, magenta, cyan, and black, respectively. It has a developing sleeves 8A, 9A, 10A, and 11A, respectively, which can keep the photosensitive belt 1 a constant distance from the respective developing means 8, 9, 10, and 11. The developing means 8, 9, 10, and 11 can develop a latent image on the photosensitive belt 1 in such a noncontact developing way. Unlike a contact development, the noncontact developing method provides an advantage that the developing means cannot prevent motion of the photosensitive belt 1. A transfer unit 12, an neutralizing bar 12A, and a cleaning unit 13 are provided. A blade 13A of the cleaning unit 13 and a toner carrying roller 13B are kept in position separated from the outside of the flexible photosensitive belt 1 during forming of the image. They can be pressed to the outside the flexible photosensitive belt 1 only during cleaning after completion of the image transference as shown in the drawing. The color image forming apparatus of the present invention is made in a process described below. First, forming of a multicolor image in the present preferred embodiment can be accomplished in accordance with an image forming system shown in Fig. 2. That is, an original image is scanned and converted to a color image data by a pickup device. The color image data is taken into the image data input part (a) in Fig. 2. The data obtained through the image data input part (a) is calculated by the image data processing part (b) having a calculation feature to produce a image data. The image data once is stored in an image memory (c). Upon recording, it is sent to a color recording part (d), such as the color image forming apparatus shown as the preferred embodiment in Fig. 1. In more specifically, a color signal output of an image reading apparatus separated from the printer is sent to the laser writing unit 7 shown in Fig. 1. A semiconductor laser of the laser writing unit 7, then, emits a laser beam. The laser beam is rotationally scanned by a polygonal mirror 7B, is passed through a f-theta lens 7C, is folded by the mirror 7D and the mirror 7E, and is projected on the outside surface of the flexible photosensitive belt 1 having a charge in advance by the electric charger 6 as charging means to draw a bright line thereon. On the other hand, when scanning starts, the laser beam is detected by an index sensor and is modulated by a first color signal. The modulated laser beam scans on the outside surface of the flexible photosensitive belt 1. The main scanning by the laser beam and the subscanning by the motion of the flexible photosensitive belt 1 allow formation of a latent image corresponding to the first color on the outside surface of the flexible photosensitive belt 1. The latent image can be developed on the outside surface of the flexible photosensitive belt 1 as toner image by a developing means 8 having a yellow toner which is a developing medium. The resulting toner image passes under a cleaning unit 13 which is separated from the outside surface of the flexible photosensitive belt 1 while the toner image is kept thereon. It then enters a succeeding copy cycle. In the copy cycle, the flexible photosensitive belt 1 is charged again by the electric charger 6. Then, a second color signal output of the image data processing part is sent into the laser writing unit 7. The color signal is written onto the outside surface of the flexible photosensitive belt 1 as was the case with the first color signal to form a latent image. The latent image is developed by a developing means 9 having a toner of a second color magenta contained therein. The magenta toner image can be formed under existence of the yellow toner image described above. A developing means 10 contains a cyan toner which can form a cyanic toner image on the outside surface of the flexible photosensitive belt 1 on the basis of a control signal generated by the image data processing part. A developing arrangement 11 contains a black toner which can overlap a black toner image to form on the outside surface of the flexible photosensitive belt 1 in a similar way. Each sleeve of developing means 8, 9, 10, and 11 has a dc bias or ac biased dc bias voltage applied thereto which make one or two components developing agents jump. This allows noncontact development on the flexible photosensitive belt 1 substrates of which is grounded. The color toner image formed on the outside surface of the flexible photosensitive belt 1 in that way is transferred on to a transference material fed through a paper feed guide 15 from a paper feed cassette 14. A top sheet of the transference material contained in the paper feed cassette 14 can be carried out by revolution of a paper feed roller 16, and can be fed through a pair of timing rollers 17 to a transfer unit 12 at a instance of forming of the image on the flexible photosensitive belt 1. The transference material having the image transferred can be securely separated from the flexible photosensitive belt 1 which abruptly changes its direction along the flexible photosensitive belt 1, can be moved upward, has the image fixed by a pair of fixing rollers 18, and are fed out through a pair of paper exit roller 19 to a tray. On the other hand, the flexible photosensitive belt 1 which finished the image transference to the transference material can be further carried to a cleaning unit 13. In the cleaning unit 13, the photosensitive belt is pressed by a blade 13A and a toner carrying roller 13B to remove the toner remained on it. After the removal, the blade 13A is released and a little after this, the toner carrying roller 13B is released to enter a new image forming process. The image forming means, including the flexible photosensitive belt 1, the guide member 4, the electric charger 6, the developing means 8, 9, 10, and 11, and the cleaning unit 13, as shown in Fig. 3, are assembled in a cartridge 30 comprising a front panel 30A and a rear panel 30B which can be detachably assembled in a main body of the color image forming apparatus as a unit. The cartridge 30 has the front panel 30A and the rear panel 30B integrated together by four stays 31, and has the image forming means held therebetween. The cartridge 30 can be vertically inserted downward into the main body along three guide rails 32 on a front and rear sides thereof to accommodate. Each of the guide rails 32 has a convex rail 32A, while the main body has concave rails (not shown). Fitting of the convex and concave rails will allow transmission of power from the main body to the image forming means and connection of electric power. The main body, as shown in Fig. 1, is constructed so that the tray can be opened substantially up right in an arrow direction in Fig. 4 together with the pair of fixing rollers 18 and the pair of paper exit roller 19. This allows vertical attaching and detaching of the cartridge 30 downward. The tray 20 has a toner container unit 50 mounted therebelow which has toner containers arranged together in series. Each of the toner containers of the toner container unit 50 contains a black, cyanic, magenta, and yellow toners, respectively, as looked toward left hand, corresponding to the developing means 8, 9, 10, and 11. With the tray closed, the toner container unit 50 can be set in position so that the toners can be supplied through respective toner exit holes 51 provided on the toner containers to respective supply ports 41 provided on a toner supply unit 40 for receiving the toners from the toner container unit 50, with the toner exit holes 51 being faced with the supply ports 41. Fig. 5 shows a rear view of the cartridge 30 with the toner container unit 50 set in position. The toner supply unit 40 is provided backside of the rear panel 30B of the cartridge 30, and is to be connected to the developing means 8, 9, 10, and 11. The toner supply unit 40 has the supply ports 41 to be connected to respective developing means 8, 9, 10, and 11. Each of the supply ports 41 has an extension part of one of a pair of stirring screws 9B built in the respective developing means 8, 9, 10, and 11. Each of the toners falling from the toner exit holes 51 can be carried into the respective the developing means 8, 9, 10, and 11 by the respective stirring screw 8B, 9B, 10B, and 11B. The extension part of each stirring screw can be fitted to the other part of the respective 8B, 9B, 10B, 11B positioned at an upper stream of revolution of each developing sleeve in connection with stirring effect. When the toner container unit 50 is set in position in the toner supply unit 40, a gear G1 coaxially integrated with a supply roller 52 built in each container can be engaged with a gear G2 of the toner supply unit 40. Operation of supplying the toner into the developing means 9 as an example by the toner container unit 50 will be described below. Fig. 6(A) is a cross-sectional view taken across A-A of Fig. 5. The gear G2 is driven by a signal output of the image data processing part depending on a detection results of image density, the supply roller 52 starts revolution through the gear G1 to make the magenta toner of the toner container fall from the toner exit holes 51 into the supply port 41. The magenta toner fallen into the supply ports 41 can be carried into the developing means 9 by revolution of the stirring screw 9B. It also can be stirred and mixed by a reverse operation of the other stirring screw. It then can be fed into a developing sleeve 9A to restore the image density. After restoration of the image density, the gear G2 is stopped by a signal output of the image data processing part depending on a detection result of image density again to finish supply of the toner. This operation can be made intermittently during the developing process. Fig. 6(B) shows a state of the toner supply unit 40 when the cartridge 30 is taken out of the main body. On a top of the toner supply unit 40 is provided a turnable turning plate 42 with a fulcrum of a shaft 42A. It is always forced toward clockwise by action of a tension spring 44 suspended on an arm 43 coaxially integrated therewith. The supply port 41 can be covered by the turning plate 42 when the cartridge 30 is detached as a single unit, thereby preventing the toner from flowing out and splashing or foreign matters from intruding in. When the cartridge 30 is attached to the main body, as shown in Fig. 6(A), the arm 43 is fitted to a push up lever 45 of the main body to be turned counterclockwise against the force of the tension spring 44. This allows turning the turning plate 42 substantially up right to make the supply ports 41 open. As the tray 20 is closed, therefore, the toner container unit 50 is reset to the state shown in Fig. 6(A). With respect to the toner container unit 50, also, when it is not set in position in the toner supply unit 40, the toner exit holes 51 can be automatically closed by shutter plates to prevent the toner from flowing out and splashing. Now, another embodiment according to the present invention will be described. Namely, in this embodiment where a color image forming apparatus comprises a belt-like image forming body arranged between a plurality of rollers, a plurality of developing devices adjacent to each other in the vicinity of an outside of the belt-like image forming body and a plurality of toner suply container for supplying toner to the plurality of developing devices, there is provided a detachable cartridge for installing at least the belt-like image forming body and the toner supply container therein, and the toner supply container is made detachable from the cartridge on the condition where the cartridge is detached from the apparatus. In a preferable embodiment as shown in Figs. 3 and 5, image forming means such as the toner container unit 50, the flexible photosensitive belt 1, the guide member 4, the scorotron electric charger 6, the plurality of developing devices and the cleaning devices 13 are installed in the cartridge 30 which is attachable to and detachable from the main body of the image forming apparatus as a unit. Fig. 5 indicates the condition of the cartridge 30, when toner container unit 50 is set in position in the cartridge 30. The cartridge 30 has the front and rear base plates 30A and 30B integrated together with the four stays 31, and incorporates the abovementioned image forming means between the plates 30A and 30B. On the front and rear sides of the cartridge 30 is provided three guide rails 32 through which the cartridge 30 is installed by being vertically inserted from an upper side into the main body. The members having convex-shaped rails 32A are used as the guide rails 32, and while the guide rail (not illustrated in the drawings) having a concave-shaped rails are provided in the main body. With the engagement between these rails, power transmission and electric power supply for the image forming means are carried out. As shown in Fig. 6 (C) which indicates a cross section corresponding to a section designated with an arrow mark A-A in Fig. 5, when the toner container unit 50 is installed in the cartridge 30, the rotatable plates 42 mounted on an end surface of the toner supply portion 40 is used as the guide for the toner container unit 50. Furthermore, the installed position of the toner container unit 50 is regulated by the rotatable plates 42. At this time, the gear G1 coaxially integrated with the supply roller 52 is meshed with the gear G2 at the side of the toner supply portion 40, thereby the power transmission system is connected. The work of toner supply to each of the developing devices by the toner supply container unit 50 is explained hereinafter, taking an example of supplying to the developing device 9. As shown in Fig. 6 (D) which indicates a condition where the toner supply container unit 50 is detached from the toner supply portion 40, the toner supply container unit 50 can be easily detached by being pulled upwardly after a coupling means (not illustrated in the drawings) is released. When the toner supply container unit 50 is detached, the shutter plate 53 is actuated to close the toner exit holes 51. On the other hand, the supply ports 41 of the toner supply portion 40 is closed with the rotatable plate 42 by rotating it around a supporting shaft 42A as a fulcrum point in the counterclockwise direction, thereby toner leakage, toner scattering and foreign material contamination are prevented. Incidentally, when the cartridge 30 is attached to or detached from the main body, the tray 20 is overhauled by being turned together with the fixing roller 18 and the sheet delivery roller 19 in the counterclockwise direction around the hinge 21 so that the cartridge 30 is vertically upwardly lifted and leased the engagement with the guide rail 32. In the abovementioned embodiment, the cartridge 30 is made detachable together with the belt-like photosensitive body and the developing devices, however, it is also possible to make it detachable together with the toner supply container and the belt-like photosensitive devices. With this arrangement, even if the elements installed in the cartridge differs from each other in the maintenance intervals and the endurancelife periods, the maintenance of the apparatus may become possible by replacing them with the spare one. In turn, a toner collecting arrangement according to the present invention will be described below. The cartridge 30, as shown in Fig. 3, has a toner carrying pipe 34 with a toner carrying screw 33 provided at its front side. One end of the toner carrying pipe 34 is made open at a bottom of the cleaning unit 13, and the other end is connected to a closed toner collecting container 4A which is a part of the guide member 4, thereby allowing the cleaning unit 13 to drive out the collected toner. The toner carrying screw 33 can be driven to revolve by a power from the main body to feed the toner collected by the cleaning unit 13 through the toner carrying pipe 34 to the closed toner collecting container 4A to accommodate. The closed toner collecting container 4A, as shown in Fig. 3, can be made smaller one occupying a part of the guide member 4 or larger one using the guide member 4 itself as accommodation box depending on a life expectancy of the cartridge 30. As a result, when the image forming means reach their life expectancy, the closed toner collecting container 4A is filled with the collected toner. It is therefore possible to fully use all arrangements and materials of the cartridge 30 in the life expectancy before it is replaced. In the construction described above, all the arrangements of the cartridge 30 including the developing means is integrated into one module which can be attached or detached. It is to be understood that the form of the invention herewitn shown and described is to be taken as a preferred embodiment. Various changes may be made in the shape, size and arrangement of parts. For example, equivalent elements may be substituted for those illustrated and described herein, parts may be reversed, and certain features of the invention may be utilized independently of the use of other features, all without departing from the scope of the invention as defined in the subjoined claims. It is intended, therefore, that all matter contained in the foregoing description and in the drawings shall be interpreted as illustrative only not as limitative of the invention. In the above-described construction of the color image forming apparatus according to the present invention which uses the belt-like image forming body and has image forming means, including the plurality of the developing means, integrated into the single cartridge, the toner container accomplished herein can be readily attached or detached with a very easy handling in the way that the cartridge is made module. As a result, each of the image forming means can be independently replace depending on its life expectancy. It is very advantageous in view of service, maintenance, and economy. Also, in the color image forming apparatus according to the present invention which has the belt-like image forming body, the toner collected can be contained with use of the space of the image forming body in a way similar to that of a color image forming apparatus having a drum-like image forming body. As a result, the color image forming apparatus can be made compact with it being capable of containing a large amount of the collected toner. The color image forming apparatus according to the present invention provides the following differences and advantages as compared with the previous color image forming apparatus in which the used toner is collected in a photosensitive drum. (1) A used toner collecting container is placed in a space inside the photosensitive belt. It can be freely shaped depending on a shape of the photosensitive belt. More specifically, the photosensitive belt can be arranged to any length and any shape as desired, and the used toner container can be made to any size and any shape at any position depending on the photosensitive belt. The used toner collecting container can be designed so that it can be virtually filled with the used toner in the life expectancy of the photosensitive belt of cartridge type. A low cost machine can be accomplished in the way that the whole cartridge then can be discarded to replace. For a high class machine the photosensitive belt of which provides a long life expectancy, the used toner collecting container can be made to be taken out of the cartridge to discard. In short, the machine can be designed compact to a desired specification depending on the life expectancy of the photosensitive body. (2) Unlike the machine in which the used toner collecting box is placed inside the photosensitive drum, the color image forming apparatus according to the present invention needs no revolving and coupling arrangements in a toner collection path from the cleaning section to the used toner collecting container even when the photosensitive belt is turning. It can therefore be constructed at a low cost with use of a simple carrying and coupling mechanism which will be free of drop and leakage of the used toner. (3) When the used toner collecting box is placed inside the photosensitive drum, it is involved in complication and difficulty in replacement arrangements of a rotatable drum, particularly in an arrangement which couples a used toner hose at its intake end. When the used toner collecting box is replaced into the photosensitive drum, it likely happens that the photosensitive body may be made dirt or scratched. For the photosensitive belt of the present invention, on the other hand, the whole cartridge can be enclosed by a plastic case with the exception of a side for the used toner collecting container or portions near the cartridge which are made open. This allows a replaceable construction to be made simple, improving the serviceability to a great extent. (4) In a process that a toner image is overlapped on an image carrier, it is necessary that the photosensitive drum has to have an outside diameter at least to cover a maximum image size. In the photosensitive belt, also, it is necessary that its length has to cover the maximum image size. The photosensitive belt, however, as described previously, can be made to any desired shape. This provides an advantage that the used toner collecting container can be made to any desired shape and size accordingly. Now, the following paragraphs describe arrangements that allow an effective collection of the used toner into the used toner collecting container shown in Figs. 7 and 8. In Fig. 7, a recording photosensitive medium 201 is a belt-like turning body. A drive means 211 drives the recording photosensitive medium 201. A used toner collecting container 202 is provided inside the recording photosensitive medium 201. A toner uniforming means 203 which embodies the present invention is provided within the used toner collecting container 202. The toner uniforming means 203 comprises a drive shaft 231 which can be revolved by the drive means 211 as interlocked therewith and a belt-like carrier 233 which also can be driven by the drive means 211 through drive shaft 231. The belt-like carrier 233 has a plurality of the toner moving fins 232 equally separated from each other in a perpendicular direction of and in parallel with the drive shaft 231. A supporting means 205 can support the used toner collecting container 202 on the main body. A cleaning means 270 can remove the toner adhered on the recording photosensitive medium 201 after an end of copying process. A powder carrying means 271 can carry the removed toner to the used toner collecting container 202. The powder carrying means 271 comprises a flexible tube and a flexible wire provided in the flexible tube which has spiral fins. The flexible wire can be revolved by the drive means 211 as interlocked therewith to rotate the spiral fins, which can carry the used toner into the used toner collecting container 202. At the inside of the toner collecting container 202, the powder carrying means 271 has a plurality of small holes for exhausting the powder. Diameters of the small holes are made larger as they are distant far from a wall of the used toner collecting container 202 through which the powder carrying means 271 passes. The toner therefore can be dropped from the end 272 into the used toner collecting container 202 in a virtual uniform way in a direction parallel with the drive shaft 231. This is effective to uniformly distribute the toner in the used toner collecting container 202. While the toner collected in the used toner collecting container 202 can be stirred and made uniform by the toner moving fins 232 provided on the belt-like carrier 233 driven by the drive shaft 231, it is carried an innermost recess distant far from the toner feed port of the used toner collecting container 202. This means that all the space of the used toner collecting container 202 can be effectively used for collection of all the toner. In Fig. 8, a recording photosensitive medium 301 made up of a belt-like turning body having an organic photosensitive material thereon is provided. A toner collecting container 302 is provided inside the belt-like turning body of the recording photosensitive medium 301. A toner supply port 321 is provided within the toner collecting container 302. A elastic fixing member 303 is provided to elastically fix the toner collecting container 302 to a 304. An impact exerting means 305 which is involved in the present invention is provided to intermittently exert an impact to the toner collecting container 302. In this embodiment, the impact exerting means 305 comprises a cam 352 turned through the gear 351 and a drive means 311 for driving the recording photosensitive medium 301 as interlocked therewith, a elastic means 353 compressed by the cam 352, and an impact member 354 which can exert an impact to the toner collecting container 302 with use of a repulsion force given when the elastic means 353 is released from the compression state at a step of the cam 352. A frequency of the impact can be set to a desired value in a way that a gear ratio of the gear 351 is properly selected. A cleaning means 370 is provided to remove the toner adhered on the recording photosensitive medium 301 after an end of a serial copying process. A powder carrying means 371 is provided to carry the toner removed to the toner collecting container 302. If the toner removed from the recording photosensitive medium 301 after an end of image transference process is put into the toner collecting container 302 by means of the powder carrying means 371 only, the toner will tend to be accumulated around the toner supply port 321 of the toner collecting container 302, resulting in nonuniform distribution of the toner in the toner collecting container 302. In the construction described above, the impact exerting means 305 can intermittently exert the impact to the toner collecting container 302 to make the toner distribution uniform in the toner collecting container 302. The colour image forming apparatus according to the present invention makes a free attachment or detachment thereof to the main body in the way that the process cartridge containing the belt-like image forming body can be separated from the group of developing means with very simple mechanism and easy handling without interference of the cartridge with the developing unit containing the group of developing means. As a result, maintenance and service can be readily fully made for the image forming means. This assures of a quality image reproduction at all times.

Claims: A colour image forming apparatus, comprising: a photoreceptor belt (1) for forming a latent image thereon, the photoreceptor belt being stretched to form a loop around plural pieces of rotatable rollers (2, 3); a cartridge (30), adapted to be detachable from the apparatus, for housing the photoreceptor belt; and a plurality of developing means (8-11) for developing the latent image on the photoreceptor belt so as to form a colour toner image, characterised in that: the plurality of developing means are disposed inside the cartridge so as to face the photoreceptor belt; and by a toner supply unit (50) including a plurality of toner containers (51) for supplying toner to the plurality of developing means, the toner supplying unit being detachably mounted on the cartridge (30). The apparatus of claim 1, wherein the toner supply unit (30) is made to be detachable from the cartridge when the cartridge has been detached from the apparatus. A colour image forming apparatus according to claim 1 or 2 further comprising: cleaning means for removing residual toner from the photoreceptor belt; a container (4A), disposed inside the loop of the photoreceptor belt, for collecting residual toner therein; and transporting means for transporting residual toner from the cleaning means to the container. An apparatus according to claim 3, wherein said container is an airtight box. An apparatus according to claim 3 or 4, further comprising guide means (2-5), disposed inside the loop of the photoreceptor belt, for guiding the photoreceptor belt, wherein the guide means forms a part of the container. An apparatus according to any one of claims 3 to 5, wherein the cartridge is provided with a handle on one side thereof, and wherein the container has an inlet for collecting residual toner on the same side as that of the handle. An apparatus according to any one of claims 3 to 6, wherein the apparatus includes upper and lower portions which are coupled with a hinge (21) so that upper portion can take a slanted open position by pivoting around the hinge, and wherein the cartridge is attached in the upper portion and the container has an inlet (34A) for collecting residual toner at an upper position when the upper portion takes the slanted open position. An apparatus according to any preceding claim, wherein the container is provided with distribution means (231-233:305) for evenly distributing residual toner in the container. An apparatus according to claim 8, wherein the distribution means is a belt-like carrier (233) provided inside the container. An apparatus according to claim 8, wherein the distribution means is means for exerting an impact force (305) to the container.

Inventors: FUKUCHI MASAKAZU, HANEDA SATOSHI, MATSUO SHUNJI, MORITA SHIZUO, FUKUCHI, MASAKAZU, HANEDA, SATOSHI, MATSUO, SHUNJI, MORITA, SHIZUO
Applicants: KONISHIROKU PHOTO IND, KONICA CORPORATION
Application year: 1990
Main classification: G03G15
IPC codes: G03G21, G03G15