Electrophotographic toner cartridge

Abstract: Electrophotographic toner cartridge for use in an electrophotographic apparatus having a housing for inserting such cartridge therein, comprising an elongated hollow body (1) containing the toner and a rotatable tile (10) which in a first position seals a discharging opening (3) of the cartridge and in a second position clears such opening (3), the tile (10) being coupled to a key which can be inserted in a keyhole of the apparatus only if the tiled (10) is in the first position and hooks in the keyhole preventing cartridge removal from the housing for any other position of the tile (10).

Description: The present invention relates to an electrophotographic toner cartridge and the related electrophotographic printing apparatus which uses such cartridge. It is known that in the electrophotographic printers and copying machines the images are formed on a printing support by means of a developing powder or toner, contained in a developing device. The toner is transferred from the developing device to an image carrying device, according to the image configuration and from there is further transferred to the printing support and fixed thereto. The toner consumption is relatively high and, even if it has been proposed to implement developing devices containing all the toner required in the useful life of such devices, it is generally required to refill the developing devices with new toner. Several kinds of toner cartridges have been developed. Basically such cartridges are closed by seals which are removed only when the cartridge has to be inserted or has been properly inserted in the printing equipment so as to avoid toner spreading at the insertion. However, the toner spreading risk is not avoided when the cartridge, theorically empty, is withdrawn from the printing equipment for replacement with a full one. In fact, some residual toner always adheres to the inner surface of the cartridges. The handling of the cartridges may cause the detaching of such toner and favours its output from the container. Even the insertion operation is not completely safe, from this point of view, because the seals and the protections which should permit the toner output from the container, only when it is properly inserted in the printing equipment, may be accidentally removed owing to an improper cartridge handling, when the cartridge is not inserted. A further problem the toner cartridge have to solve is the one of a uniform distribution of the toner in the whole extension of the developer, as well as the one of the relative seal between developing device and cartridge. A further problem is the one to provide a shape of the cartridge which assure the full usage of the toner contained in the cartridge and avoid the permanence of residual toner in the cartridge without need of shaking operations, which necessarily induce air flow and turbolence near the cartridge and favour toner spreading. Lastly, an essential requisite of such cartridges intended to be used only once, must be the constructive simplicity and the low cost of the container, which must be achieved without requiring constructive complications and cost increase of the equipment for which they are intended. All these problems are overcome by the electrophotographic toner cartridge which is the object of the present invention and by the printing equipment which makes use of such cartridge as defined in claims 1 and 7. Basically, according to a first aspect of the invention, the cartridge is provided with a closing tile coupled to locking devices interacting with the equipment, which locking devices enable the cartridge removal from the equipment only if the related closing tile is closed and prevents the output of any residual toner, if any. According to a further aspect of the invention, the cartridge is provided with blocking means which prevents the accidental opening of the closing tile if the cartridge is not properly inserted in the equipment. According to further aspects of the invention the blocking means exerts an elastic interaction force between cartridge and equipment which force prevents any skaking of the cartridge in its housing, due to equipment vibrations, and further provides for good seal between developing device and cartridge, even if a reasonable allowance is provided between housing and cartridge for easy of insertion. The features and the advantages of the invention will appear more clearly from the following description of a preferred form of embodiment and from the enclosed drawings where: Figure 1 shows in perspective, exploded view an electrophotographic toner cartridge designed in accordance with the present invention. Figure 2 shows in perspective view an electrophotographic printing apparatus using the cartridge of Fig. 1, as well as such cartridge, positioned for insertion in the apparatus. Figure 3 shows in perspective, exploded view, a preferred embodiment of blocking means for the cartridge of the present invention. Figure 1 shows in perspective exploded view an electrophotographic toner cartridge designed in accordance with the present invention. The cartridge comprises a hollow prismatic body or drawer 1 closed on the upper side by a flat cover 2. The two elements are preferably obtained by plastic molding, in case the plastic material being suitably reinforced by glass fibers. The two elements are welded together in the course of the cartridge manufacturing process. The cartridge is relatively elongated in the direction indicated by arrow F1 and has a section, transverse to such direction, having the shape of an isosceles trapeze with the shorter base being located downward, with reference to the drawing, which shows the cartridge in the normal operating position. The drawer 1 has an opening 3, substantially corresponding to the whole lower side of the prismatic body, which therefore consists in two slanted side plates 4,5 and two end plates 6,7 (or rear and front plate respectively) perpendicular to the axis of the prism, hence having the shape of an isosceles trapeze, except for the trapeze lower base, which is "radiused" to the trapeze sides by a circumference arc. End plates 6,7 each have a round opening therein, respectively referenced by numerals 8,9. The opening are located at a distance from the upper edge of the plates, sligthly greater than the distance from the circumference arc which defines the lower side of the plates. A closing tile 10 is located in the drawer 1. The tile is shaped as a cylindrical arc ended by two circular sectors, perpendicular to the rotation axix of the cylindrical arc and reinforced by a radial rib 131 extending between and connecting the two end sectors 11,12. End sectors 11,12 each have, in correspondence to the rotation axis of the tile, two semicircular openings 13,14 and 15,16 respectively. The semicircular openings are divided by the radial rib 13. The tile length, is equal to the distance between plates 6,7 less possible manufacturing allowances, so that the tile may be inserted in the drawer 1, the openings 13,14 and 15,16 being axially aligned with the corresponding openings 8,9. The size of tile 10 and sectors 11,12 is such that when the tile is so inserted in the drawer 1, the tile edges tally with and partially overlap the drawer edges which form opening 3, thus sealing it. A pin 17 having locking resilient tooth 18 is inserted in opening 8, the tooth being inserted in openings 13,14. Another pin 19, having locking resilient tooth 20, is inserted in opening 9, the tooth 20 being inserted in openings 15,16. The two pins act as journal for tile 10, which can rotate in drawer 1 from a first position, for which the opening 3 is closed, to a second position, opposite and rotated of 180 as to the first one, for which the opening 3 is completely open. A knob 21, steady with pin 19, enables to manually perform the rotation of tile 10, from the cartridge outside, when the cover 2 is welded to drawer 1. To this purpose it may be noted that tooth 20 of pin 19 offer a dap to rib 15 and enable to exert a torque on the tile. Pin 17 in turn has an external teeth 22 so as to form a key rotatable around the rotation axis of the tile. Tooth 18 of pin 17 offer a dap to rib 131 and retain the teeth 22 in a predetermined angular relation as to tile 10. Teeth 22, when pin 17 is inserted in opening 8, is suitably spaced apart from plate 6. A plastic leaf 23 is fixed (for instance by welding), at its lower end 100, to the lower part of plate 6. Leaf 23 has an opening 24 having a shape equal to the one of teeth 22 and is preformed so as to lay, when at rest, in the same plane of teeth 22 and to form a keyhole 24 where teeth 22 is inserted, thus preventing rotation of the key formed by teeth 22 and pin 17. By exerting a suitable pressure on leaf 23, near the keyhole, towards plate 6, the leaf 23 may be bent and brought in contact with plate 6, thus clearing teeth 22 and allowing the key 22,17 to rotate. In this condition the whole set comprising pin 17, tile 10 and pin 19 may be rotated by acting on knob 21. The function of the cartridge is to store developing powded which is extremely thin, and to avoid its spreading. Therefore the inner surface of drawer 1, at the edges which define the opening 3, that is the discharging opening through which the toner is discharged from the cartridge into a developing device, is suitably flocked, that is coated with a material acting as a felt gasket. Suitable gaskets 25,26, in felt or equivalent material, are further inserted on pins 17 and 19 to assure the sealing at the pivots. The cartridge filling operation, once the cartridge is assembled and it is assured that opening 3 is sealed by tile 10, may be performed through an opening 27, provided in plate 6 (or plate 7). This opening 27 may then be closed by a plastic plug sealed by glew or welding.It is clear that for greater safety the opening 3 may be further sealed, externally to the cartridge, by a tacky plastic sheet, which is removed immediately before use of the cartridge. As a further constructive detail, it may be noted that plate 7 has, two tooth 29,30 on the external surface. These tooth cooperate with a teeth 31, located on knob 21, so as to allow for a knob rotation (hence for rotation of the elements coupled to the knob) limited to 180 from a closing position to an opening position. It is clear that tooth 29,30,31 may be replaced by any equivalent arrangement such as a combination teeth-groove. Even if the use of the described cartridge may be considered as given, Fig.2 shows the cooperation of the cartridge with an electrophotographic printing apparatus designed for using such cartridge. The apparatus, which may be a photocopying machine or an electrophotographic printer or similar equipment, comprises several elements not shown (such as a photosensitive drum, fusing devices, paper feeding devices, an electronic control unit, and so on) and in addition a developing device 32. The apparatus is shown in the whole by dotted lines as a prismatic box 33, containing the developing device 32. The developing device consists in a prismatic box housed in the apparatus and having a developing roller 34 and a housing 37 open at one side and having the same shape and size of the toner cartridge. The cartridge 35 is inserted, through the side opening in the housing 37 of the developing device, according to the direction indicated by arrow 36, that is according to the axis direction of the prismatic box. Housing 37 has a lower, elongated opening 38, below which a toner collecting tank is located and through which the toner gets in contact with the developing roller 34. A side plate 39 opposite to the side insertion opening, has a keyhole 40, having the same shape of teeth 22 (Fig. 1). In this way, when the cartridge 35 is inserted in the housing 37, the pressure manually exerted on the cartridge towards wall 39, causes the bending of leaf 23 which clears the teeth 22. Teeth 22, in turns and owing to the pressure exerted on the cartridge through knob 21, enters keyhole 40 and only when completely inserted, and protruding externally to the thickness of plate 39, is free to rotate, owing to a torque exerted on knob 21. It is therefore clear that the pair teeth 22, keyhole 40 assures that the complete insertion of the catridge 35 in the housing 37 and its removal from the housing can be performed only when the cartridge is closed (that is tile 10 seals opening 3). Leaf 23 further prevents any accidental opening of cartridge 35 when this one is not completely inserted in housing 37. It may be noted that leaf 23 performs further useful functions by its cooperation with plate 39 of the developing device. A first function is to provide, owing to its resiliency, a suitable holding thrust between plate 39 and cartridge 35, when the cartridge is installed. This thrust, tending to eject the cartridge from the housing and opposed by teeth 22 holding in keyhole 40, recovers possible axial allowances between cartridge and housing and prevents possible rotation of the set key 17, tile 10, knob 21, which may be induced by apparatus vibrations. It further prevents cartridge chattering in the housing. A second function performed by the interaction of leaf 23 with plate 39 is the one to exert a torque on the cartridge which tends to lay down it steadily on the lower walls of the housing 37, thus recovering the allowance required for an easy insertion of the cartridge in the housing. The steady contact between lower sides of the cartridge and related housing prevents toner infiltration therebetween and the risk that toner so scattered is removed with the cartridge, when it is subsequently replaced. A third function is related to the problem of the sealing function of tile 10 as to the cartridge side walls. To assure the sealing and avoid toner scattering it is advisable that, depending on the relative resiliency of the whole cartridge, which is not perfectly rigid, the slanted side plates 4,5 of drawer 1 be suitably preformed as bent inwardly. In the alternative tile 10, rather than being perfectly cylindrical, may be slighty toroidal. In this way a suitable contact pressure is exerted between the side plates 4,5 edges which define opening 3 and the tile 10. This contact pressure, in turn, induces a friction which may render difficult the rotation of tile 10. Resilient leaf 23, cantilevered on the lower part of plate 6, when pushed by wall 39, induces some bending and deformation of plate 6 and slanted side plates 4,5 which tend to open, thus reducing and in case zeroing the contact pressure with tile 10. Therefore rotation of tile 10 may be performed much more easily. The other advantages, already mentioned, of the cartridge of the invention, are the result of the elongated shape of the cartridge with a discharging opening extending for the whole length, thus allowing a uniform toner distribution for the whole extension of the collecting tank in the developing unit. The cartridge side walls, having a preferred sloping of 45 on the horizontal plane, form a discharging hopper which assures the complete output of the toner from the cartridge, when it is opened by rotation of tile 10. It is clear that the preceding description is related to a preferred form of embodiment of the invention cartridge and that several changes can be made within the scope of the appended claims. The shape of key 22 and leaf 23 may be choosen at will. The leaf 23, as shown in Fig.3, may be substituted by a plastic prismatic core 41, having a keyhole 42 with the same shape of the key formed by teeth 22 and pin 17. The core 41 is inserted on pin 17 so as to be interposed between teeth 22 and plate 6, when the cartridge is assembled. A bushing 43, having a prismatic seat, is formed in relief on the plate 6 and forms a seat for the core 41, which can axially slide therein, but cannot rotate. A compression spring 44 is interposed between core 41 and plate 6. The spring 44 holds the core in a position far from plate 6 and blocking teeth 22. When the cartridge 35 is inserted in the housing 37, the housing wall 39 (or a suitable ledge surrounding keyhole 40 and abutting from wall 39) pushes core 41 inside to bushing 43, clearing the key 22,17 which can be turned. By this arrangement, some of the already mentioned advantages are forfaited, but the advantage is achieved that the blocking element is integrally protected against any external action except the one of wall 39 (or the ledge protruding therefrom). Eventually, in the same perspective of giving up some of the mentioned advantages, the leaf 23 may be completely omitted and in case replaced by a safety device which prevents the tile 10 rotation if an adequate axial pressure is not exerted on knob 21. For example knob 21, rather than being steady with pin 19, may be axially slidable and idle thereon. Pin 19 may be provided with a key and an helicoidal spring which keeps the knob in a position far from the cartridge body and prevents the key from interacting with a corresponding post of the knob. In this position knob 21 may freely rotate on pin 19 without causing rotation of key 19 and tile 10. When an adequate push is exerted on knob 21 towards the cartridge body, as it occurs for properly inserting the cartridge in housing 37 of the developing device, the spring action is overcome and knob 12 is caused to engage with pin 19. In this condition, rotation of knob 21 causes rotation of the tile 10 and the hooking of teeth 22 withing keyhole 40. Even the cartridge shape, shown as having an isosceles trapeze section, can be changed to meet contingent requirements, being of essence that the cartridge be elongated in an axial direction and that the shape be prismatic or cylindrical or mixed (for containing the tile and allowing its rotation in the same axial direction and for allowing the cartridge insertion in housing 37 according to the same axial direction as well).

Claims: Toner cartridge (10), for use in an electrophotographic apparatus (32) having a housing (37) for insertion of said cartridge therein, and apparatus hooking means (40) for preventing the removal of said cartridge from said housing, characterized in that said toner cartridge comprises a hollow generically prismatic body (1) elongated along an axis and ended with a first (7) and a second (6)plate perpendicular to said axis, said prismatic body having an elongated opening (3) corresponding to a side of said prismatic body, said first and second plates having respectively a first and a second circular opening (8,9) therein, said prismatic body (1) containing a tile (10) for closing said elongated opening, said tile being in form of a cylindrical arc having a rotation axis and being ended by two circular sectors (11,12) perpendicular to said rotation axis, said tile being journaled in said circular openings for taking a plurality of angular positions including a first and a second position, said tile (10), when in said first position, sealing said elongated opening (3), when in said second position entirely clearing said elongated opening (3), actuating means (21), external to said prismatic body, and coupled to said tile through said first circular opening (9), for rotating said tile from said first to said second position and viceversa, second hooking means (22), external to said prismatic body (1) and coupled to said tile (10) through on of said circular openings (8,9), for rotating together with said tile (1), said second hooking means (22) being operative with said apparatus hooking means (40) for preventing removal of said cartridge from said housing (37), once operatively inserted in said housing (37), for any angular position of said tile (1) other than said first angular position, and for allowing removal of said cartridge (1) from said housing (37), only for said first angular position. Toner cartridge as claimed in claim 1 where an inner surface of said prismatic body (1), surrounding said elongated opening (3) is flocked. Toner cartridge as claimed in claim 1 comprising blocking means (23,24) movable in at least a blocking position and an unblocking position, said blocking means, when in a position other than said unblocking position, preventing rotation of said tile (10) from said first position to any other position, said blocking means being moved in said unblocking position by insertion of said cartridge (1) in said housing (37). Toner cartridge as claimed in claim 3 where said second hooking means (22) consist in a key (17) having a hooking teeth (22) and said blocking means (23,24) comprised resilient element (23) fixed to said second plate (6), normally in said blocking position and resiliently deformable by insertion of said cartridge in said housing (37), for moving to said unblocking position. Toner cartridge as in claim 4, where said resilient element (23) has a first free end (100) acting on said key for blocking it and a second end cantilevered to said second plate (6), near an edge of said second plate close to said elongated opening (3), whereby the insertion of said cartridge in said housing (37) and the resulting resilient deformation of said element, induces a torque on said cartridge which pushes side walls (4,5) of said prismatic body adjacent to said elongated opening (3), towards corresponding walls of said housing. Toner cartridge as in claim 3 where said second hooking means (17,22) consists in a key (17,22) having a hoooking teeth (22) and said blocking means comprises a bushing (43) steady with said second plate (16), a core (41) axially slideable in said bushing (43) and having a seat (42) for receiving said key and resilient means (44) for imparting to said core (41) a blocking position for which said key (17,22) is housed in said seat (42) and cannot turn, said core (41) taking an unblocking position and allowing rotation of said key, when said cartridge is inserted in said apparatus housing. Electrophotographic apparatus comprising a developing device (32), and a housing (27) for a removable toner cartridge, said housing (27) being generically shaped as a prism elongated in an axial direction, and having two ends, an end being closed by a wall (39) perpendicular to said axial direction, the other end being open for insertion of said removable toner cartridge in said housing, characterized in that said cartridge (1) comprises a hollow generically prismatic body (1) elongated along an axis and ended with a first (7) and a second plate (6) perpendicular to said axis, said prismatic body (1) having a elongated opening (3) corresponding to a side of said prismatic body (1), said first (7) and second plates (8) having respectively a first (9) and a second (8) circular opening therein,said prismatic body (1) containing a tile (10) for closing said elongated opening, said tile being in form of a cylindrical arc having a rotation axis and being ended by two circular sectors (11,12) perpendicular to said rotation axis, said tile (10) being journaled in said circular openings for taking a plurality of angular positions including a first and a second position, said tile (10), when in said first position, sealing said elongated opening (3), when in said second position entirely clearing said elongated opening (3), actuating means (21), external to said prismatic body (1), and coupled to said tile (10) through said first circular opening (9), for rotating said tile (10) from said first to said second position and viceversa, first hooking means (17,22), external to said prismatic body (1) and coupled to said tile (10) through said second circular opening (8), for rotating together with said tile, said apparatus housing being provided with second hooking means (40), said first hooking means (17,22) being operative with said second hooking means (40) for preventing removal of said cartridge (1) from said housing (37), once operatively inserted in said housing (37), for any angular position of said tile (10) other than said first angular position, and for allowing removal of said cartridge from said apparatus housing, only for said first angular position. Apparatus as claimed in claim 7, where said first hooking means (17,22) consists in a key having a hooking teeth (22) and said second hooking means (40) consists in a keyhole (40) for said key, in said end wall (39) of said apparatus housing. Apparatus as in claim 8 where said cartridge (1) comprises blocking means consisting in a resilient element (23) fixed to said second plate (6) and where said resilient element (23) normally in a rest position interferes with rotation of said key (22) and prevents rotation of said tile (10) from said first position to any other position, said resilient element (23) being deformed by said end wall (39) acting on said element (23), when said cartridge (1) is inserted in said apparatus housing (37) , and taking an unblocking position for which said element (23) does not interfere with the rotation of said key (22) and allows said tile (10) to be rotated to said second position and the hooking of said key (22) in said keyhole (40), whereby preventing removal of said cartridge (1) from said housing (37). Apparatus as in claim 7 where said cartridge comprises blocking means for said key, said blocking means comprising a bushing (43) steady with said second plate (6), a core (41) axially slideable in said bushing and having a seat (42) for receiving said key (22) and resilient means (44) for imparting to said core (41) a blocking position for which said key (22) is housed in said seat (42) and cannot turn, said core (41) taking an unblocking position and allowing rotation of said key (22), when said cartridge is inserted in said apparatus housing (37).

Inventors: CASSIANO COSIMO, LADU ANGELO, CASSIANO, COSIMO, LADU, ANGELO
Applicants: BULL HN INFORMATION SYST, BULL HN INFORMATION SYSTEMS ITALIA S.P.A.
Application year: 1990
Main classification: G03G15
IPC codes: G03G15