TONER CARTRIDGE

Abstract: A detachable toner cartridge (11) to be used for an electrophotographic printing apparatus, which does not require high precision in working, in which toner discharge ports (18, 19) are provided respectively in an outer tube (12) and inner tube (13) nested in tight contact with each other and adapted to positionally agree with each other by turning the toner discharging inner tube (13) to discharge toner (30), and the degree of contact between the both tubes is increased with pressure exerted on the inner tube in the circumferential direction thereof for preventing leakage of toner.

Description: TECHNICAL FIELD The present invention relates to a toner cartridge for feeding toner to electrophotographic recorders and the like. BACKGROUND TECHNOLOGY Cylindrical toner cartridges have been known as conventional toner cartridges. The cartridge of this type is composed of an outer cylinder, an inner cylinder which rotatively contacts the inner surface of the outer cylinder and a pair of caps attached to the both ends of the inner cylinder. The inner cylinder has an empty space therein to accommodate toner. A plurality of toner discharge outlets are defined on the side surface of the outer cylinder in the longitudinal direction thereof while a plurality of toner discharge outlets are defined on the side surface of the inner cylinder too. The caps are also in contact with the both ends of the outer cylinder, one of the caps having a toner filling opening which is usually equipped with a cap. A method of filling toner in the toner cartridge set forth above will be described hereinafter. Firstly, the inner cylinder is turned so that the toner discharge outlet of the inner cylinder may not overlap the toner discharge outlet of the outer cylinder. Then the cap is removed from the toner filling opening and the toner is filled in the toner cartridge. Thereafter the cap is put on the toner filling opening. In order to feed the toner to the electrophotographic recorder using the toner cartridge which is filled with toner in the manner described above, the toner cartridge is attached to the electrophotographic recorder at a predetermined position thereof while the outer toner discharge outlet directed downward. Thereafter the inner cylinder is turned by a driving means so as to overlap the inner toner outlet with the outer toner outlet. As a result, the toner is fed to the electrophotographic recorder through the conformed and overlapped inner and outer toner discharge outlets The toner cartridge set forth above, however, had the following problems. It was difficult to manufacture with the inner and outer cylinders in the manner that the inner cylinder contacts an inner surface of the outer cylinder and at the same time rotatable with respect to the outer cylinder. When the outer diameter of the inner cylinder is manufactured to be less than the inner diameter of the outer cylinder, a gap is defined between the inner and outer cylinders, which causes leakage of the toner through the gap between the cylinders. When the outer diameter of the inner cylinder is manufactured with high accuracy so as to conform to the inner diameter of the outer cylinder to prevent the leakage of the toner, the yield of the inner cylinder is decreased to thereby enhance the manufacturing cost. The applicant of the present invention previously proposed a method of providing a cutaway portion at a part of the outer cylinder for smoothing the sliding motion of the inner cylinder when the outer diameter of the inner cylinder is manufactured to be the same as the inner diameter of the outer cylinder (Japanese Patent Application No. 1-122439). The cutaway portion is defined on the side surface of the outer cylinder extending from the both ends thereof where it does not overlap the toner discharge outlets of the outer and inner cylinders. This cutaway portion, however, was not enough to sufficiently reduce sliding friction between the outer and inner cylinders so that the turning of the inner cylinder was difficult. JP-A-60-147770 discloses a toner cartridge according to the preamble of claim 1, wherein the inner cylinder is rigid and has a C-shaped section at a center part of his length, which defines a toner discharge outlet. An object of the present invention is to provide a toner cartridge which has a high sealing performance and an easily turnable inner cylinder and which does not require so high accuracy in manufacturing the outer and inner cylinders thereof. With regard to the above mentioned toner cartridge this object is solved by the characterizing features of claim 1. JP-U-01-85750 discloses a toner cartridge, wherein an inner cylinder is formed of an elastic member. The ends of the elastic member are a pressing means which presses against an outer cylinder. The inner cylinder of the toner cartridge according to the present invention is composed of a flexible member and has a partially cutaway cylindrical shape, i.e. a C-shaped cross section and an inner toner discharge outlet which is defined in a partially cutaway portion of the inner cylinder, namely, radially between one circumferential end and the other circumferential end of the inner cylinder. Furthermore, the one circumferential end and the other circumferential end of the inner cylinder are brought into contact with the inner wall surface of the outer cylinder in the circumferential direction thereof by applying pressure thereto in the circumferential direction of the inner cylinder. Consequently, no gap is generated between the one circumferential end and the other circumferential end of the inner cylinder and the inner wall surface of the outer cylinder, which eliminates the toner leakage. Since the inner cylinder is made of the flexible member and formed of the C-shape in cross section, it is expected to manufacture the toner cartridge of a high yield can be expected without generating the gap between the cylinders or without increasing rotational load due to the variation of dimensions of the cylinders. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partially cutaway perspective view of a toner cartridge according to a first embodiment of the present invention, Fig. 2 is a perspective view showing an inner cylinder of the toner cartridge according to the first embodiment, Fig. 3 is a longitudinal cross-section of the toner cartridge according to the first embodiment, Fig. 4 is a lateral cross-section of the toner cartridge showing an operation of the first embodiment, Fig. 5 is a partial perspective view of a toner cartridge according to a second embodiment, Fig. 6 is a partially cutaway perspective view of a toner cartridge according to a third embodiment, Fig. 7 is cross sectional view of Fig. 6 taken along lines A-A, Fig. 8 is a perspective view of a B portion of Fig. 6 omitting an outer cylinder, Fig. 9 is a partially cutaway perspective view of a toner cartridge according to a fourth embodiment, Fig. 10 is an enlarged view of a C portion of Fig. 9, Fig. 11 is a partially cutaway perspective view of a toner cartridge according to a fifth embodiment, Fig. 12 is a view as viewed from the arrows E-E of Fig. 12, where a cap 27 of Fig. 11 is omitted, and Fig. 13 is a cross sectional view taken along the arrows F-F of Fig. 13. BEST MODE FOR CARRYING OUT THE INVENTION FIRST EMBODIMENT A toner cartridge according to the first embodiment of the present invention will be described with reference to the partially cutaway perspective view of Fig. 1. The toner cartridge 11, as shown in the same figure, comprises an outer cylinder 12, an inner cylinder 13 and caps 14 and 15. The outer cylinder 12 is composed of a thin plate. Openings 16 and 17 are defined at the both end of the outer cylinder 12. A plurality of outer toner discharge outlets 18 are radially defined in the outer cylinder 12 and extend in the longitudinal direction thereof. Denoted at 12a is an outer cylinder rib. On the other hand, the inner cylinder 13 is composed of a flexible plate bent in the direction of the arrow 80 as illustrated in Fig. 2 The inner cylinder 13 has a substantially C-shaped cross section. The resilience of the inner cylinder 13 is used to apply a pressure to the inner cylinder 13 in the circumferential direction thereof. The inner cylinder 13 has one circumferential end 13a and the other circumferential end 13b, which form a gap therebetween serving as an inner toner discharge outlet 19. The length of the inner toner discharge outlet 19 in the circumferential direction is defined substantially same as that of the outer toner discharge outlets 18 described above. The inner cylinder 13 has cap fitting portions 20 and 21 at both longitudinal ends thereof. Furthermore, holes 22a, 22b and 22c are defined on the cap fitting portion 20 while holes 23a, 23b and 23c are defined on the cap fitting portion 21. The inner cylinder 13 is turnably in contact with and pressed against the inner surface of the outer cylinder 12 at least at the circumferential ends 13a and 13b thereof. The caps 14 and 15 are fixed to the cap fitting portions 20 and 21 by inserting pawls 24 and 25 protruding from the caps 14 and 15 into the corresponding holes 22a, 22b, 22c, 23a, 23b and 23c respectively as illustrated in Fig. 3. The caps 14 and 15 has seals 26 formed of elastic member on the outer circumference thereof which closely contact the inner surface of the outer cylinder 12 so as to prevent the toner, not shown, from leaking through the sides of the caps 14 and 15. The cap 14 has a toner filling inlet 14a on which a cap 27 is put. In order to fill toner in the thus constructed toner cartridge 11, the inner cylinder 13 is turned to the position where the inner toner discharge outlet 19 and the outer toner discharge outlet 18 do not overlap each other in the same manner as employed in the conventional method. The inner cylinder 13 can be turned by turning the caps 14 and 15. Thereafter the cap 27 is removed from the toner filling inlet 14a, toner is filled in the toner cartridge through the toner filling inlet 14a, and then the cap 27 is put thereon. The operation of discharging the toner from the toner cartridge 11 will be described with reference to the cross sectional view in Fig. 4. As shown in Fig. 4(a), the inner cylinder 13 is turned to the position where the inner toner discharge outlet 19 of the inner cylinder 13 and the outer toner discharge outlet 18 of the outer cylinder 12 do not overlap each other, e.g. the former is turned at 90° relative to the latter, and then toner 30 is filled in the toner cartridge 11. At this time, the circumferential ends 13a and 13b of the inner cylinder 13 are brought in close contact with the inner surface 12b of the outer cylinder 12 so that no gap is generated between the circumferential ends 13a and 13b of the inner cylinder 13 and the inner surface 12b of the outer cylinder 12 and the toner 30 is not leaked. In order to discharge the toner 30 from the toner cartridge 11 filled therein, the inner cylinder 13 is turned at first. It turns smoothly as it can radially move freely. As shown in Fig. 4(b), the inner toner discharge outlet 19 and the outer toner discharge outlet 18 are substantially overlapped each other, and the toner 30 is discharged therethrough. Inasmuch as the inner cylinder 13 of the toner cartridge 11 is formed of a bent elastic plate which closely contacts the inner surface of the outer cylinder 12 by its resilience, it need not be manufactured with high accuracy. As a result, the yield of the toner cartridge 11 is enhanced and its manufacturing cost is reduced. SECOND EMBODIMENT Although the outer cylinder 12, which has no cutaway portion, is employed in the first embodiment of the present invention, it is also possible to employ the outer cylinder having a cutaway portion such as described in the foregoing BACKGROUND TECHNOLOGY, i.e. Japanese Patent Application No. 1-122439. Fig. 5 is a partially cutaway perspective view of the toner cartridge according to the second embodiment. In this case, the cutaway portion 31 is defined at a position where it does not overlap the inner toner discharge outlet 19 even if the inner cylinder 13 is turned. In the second embodiment, the inner cylinder 13 is also formed of a bent elastic plate which is radially pressed against the outer cylinder 12 by its resilience. THIRD EMBODIMENT The third embodiment of the present invention will be described with reference to Fig. 6 to Fig. 8. In the same figures, components which are the same as illustrated in Fig. 1 are denoted at the same numerals. According to the third embodiment, the outer cylinder 12 has a stopper 41 at a portion of the inner surface of the outer cylinder 12 to stop the other circumferential end 13b of the inner cylinder 13. The stopper 41 is provided to stop the inner cylinder 13 at a position where the outer toner discharge outlet 18 of the outer cylinder 12 and the inner toner discharge outlet 19 of the inner cylinder 13 do not overlap each other. The stopper 41 has substantially the same length as that of the inner cylinder 13 in the longitudinal direction, and has the same thickness as that of the inner cylinder 13 so that a toner stirring member, not shown, may rotatably contact the inner surface of the inner cylinder 13. At the side of the both longitudinal ends of the inner cylinder 13, holes 22a, 22b, 22c, 23a, 23b and 23c are defined, and engage the pawls 24a, 24b, 24c, 25a, 25b and 25c of the caps 14 and 15 as in the first embodiment. There are gaps between the holes 22 and 23 and the pawls 24 and 25 so that the pawls 24 and 25 may be able to turn about 6° in the turning direction of the caps 14 and 15. The caps 14 and 15 have projecting member 42 and 43 which are fixedly mounted thereon at the central portion thereof and have elasticity at the circumferential portion thereof. Consequently, the caps 14 and 15 are integrally formed with the pawls 24 and 25 and the projecting members 42 and 43. When, for example, the cap 15 is turned in the direction of the arrow 90, the pawls 25a, 25b and 25c are turned in the same direction as much as 6° and the turning force is also applied to the projecting members 43. However, one circumferential end 13a of the inner cylinder 13 contacts the projecting member 43 and the other end 13b thereof is stopped by the stopper 41, therefore the projecting member 43 is bent in the turning direction as shown in Fig. 7. That is, when the cap 15 is turned in the direction of the arrow 90, the pawls 25a, 25b and 25c also turns about 6° and the projecting member 43 is bent about 6° in the turning direction so as to push the circumferential end 13a of the inner cylinder 13 in the circumferential direction thereof. As a result, the inner cylinder 13 is radially expanded so that it come to close contact with the inner surface of the outer cylinder 12. At this state, pins 45 and 46 are inserted into the fixing holes 44 provided on the side surface of the cap and the fixing holes (not shown) provided on the side surface of the outer cylinder 12 so as to fixedly mount the caps 14 and 15 to the outer cylinder 12. For feeding the toner to the electrophotographic recorder, firstly the operator removes pins 45 and 46 so that the inner cylinder 13 and the caps 14 and 15 may be rotatable relative to the outer cylinder 12. Thereafter, the operator installs the toner cartridge 11 in the electrophotographic recorder (not shown) and turns the caps 14 and 15 in the reverse direction to the arrow 90. Consequently, the pawls 24 and 25 integrated with the caps 14 and 15 turns the inner cylinder 13 as they engage the holes 22 and 23. As a result, the inner toner discharge outlet 19 of the inner cylinder 13 and the outer toner discharge outlet 18 of the outer cylinder 12 are overlapped each other, so that the toner is fed to the electrophotographic recorder therethrough. According to the third embodiment, the projecting members 42 and 43 are bent to push the inner cylinder 13 in the circumferential direction thereof so that the inner cylinder comes to close contact with the outer cylinder. FOURTH EMBODIMENT The fourth embodiment is substantially same as the third embodiment. Fig. 9 is a partially cutaway perspective view of the toner cartridge according to the fourth embodiment, wherein the same components are denoted at the same numerals and the illustration thereof are partially omitted. The third embodiment employed the pins 45 and 46 to fix the caps 14 and 15 to the outer cylinder while the fourth embodiment employs easily destructible projections. That is, the caps 14 and 15 are equipped with projections 51 and 52 on the outer circumference thereof, and the projections 51 and 52 engages the cutaway portion 53 and 54 which are provided at the position on the side surfaces of the outer cylinder 12 corresponding to the projections. Furthermore, a groove 55 is provided on the outer surface of the cap 14 so as to facilitate the breaking of the projection 51 as illustrated in Fig. 10. Thus, the projection 51 is broken at D portion in Fig. 10, so that the cap becomes rotatable relative to the outer cylinder. In order to feed the toner to the electrophotographic recorder, the operator breaks the projections 51 and 52 to make the caps rotatable, thereafter carries out the operation of toner feeding in the same manner as in the third embodiment. FIFTH EMBODIMENT The toner cartridge according to the fifth embodiment will be described with reference to Fig. 11 to Fig. 13. The same components as in Fig. 1 are denoted at the same numerals. According to the fifth embodiment, stopper 61 and 62 are provided inside and integrally with the caps 14 and 15. As a result, the inner cylinder 13 are held between the stoppers 61 and 62 at the end 13a of the inner cylinder and the stopper 41 of the outer cylinder 12 at the other end of the inner cylinder. On the other hand, leaf springs 63 and 64 are provided at the edge of the caps 14 and 15. The leaf spring is detachably provided so that one end thereof engage the end portion 12c of the outer cylinder 12 and the other end thereof engage the edge portion 14a of the cap 14 and turns the cap 14 in the direction of the arrow 95 relative to the outer cylinder 12 as illustrated in Fig. 12. The leaf spring 64 is also disposed in the same manner as the leaf spring 63, and turns the cap 15 in the direction of the arrow 95. The stoppers 61 and 62 push the end portion 13a of the inner cylinder 13 in the circumferential direction thereof as the caps 14 and 15 are turned. Thus the leaf springs 63 and 64 push the end portion 13a of the inner cylinder 13 in the circumferential direction thereof, so that the inner cylinder 13 is brought into closer contact with the outer cylinder 12. In order to feed the toner to the electrophotographic recorder, the operator previously removes the leaf springs 63 and 64 so as to make the caps rotatable, thereafter carries out the toner feeding operation in the same manner as described in the foregoing embodiments. Inasmuch as the detachable leaf springs are employed in the fifth embodiment, the projection 42 and 43 need not be provided for generating a pushing force as in the third and fourth embodiments, so that the structure of the toner cartridge can be simplified. The two leaf springs 63 and 64 can be of the same shape, which facilitates the assembling operation owing to its bilateral symmetry. INDUSTRIAL UTILIZATION As described above, the toner cartridge according to the present invention is adapted for use in the electrophotographic printers or duplicators which employ LED, laser beam, etc. as a light source for forming a static latent image, particularly to small and economical electrophotographic printers.

Claims: A toner cartridge (11) comprising an outer cylinder (12), an inner hollow cylinder (13) which contacts an inner surface of the outer cylinder and caps (14, 15) put on both ends of the outer and inner cylinders wherein toner filled in the inner cylinder is discharged through an outer discharge outlet (18) provided on the side surface of the outer cylinder and through an inner toner discharge outlet (19) when the both toner discharge outlets are overlapped with each other by turning the inner cylinder, characterized in that: the inner cylinder (13) is formed of an elastic member and has a C-shaped cross section in the long direction in the whole length; and the toner discharge outlet (18) is defined between one circumferential end (13a) and another circumferential end (13b) of the inner cylinder; the inner cylinder (13) is also a pressing means which presses the inner wall surface of the outer cylinder (12) closely by the one circumferential end (13a) and the other circumferential end (13b) of the inner cylinder in the radial direction; and the toner cartridge further comprises a connecting means (22a-c, 24; 23a-c, 25) for interlocking the cap (14; 15) and the inner cylinder (13) when the cap is turned. A toner cartridge according to claim 1, characterized in that the inner cylinder (13) is formed of a bent elastic plate and the pressing means makes use of said bent elastic plate itself. A toner cartridge according to claim 2, characterized in that the connecting means comprises holes (22a-c, 23a-c) provided at the end portions (20, 21) of the inner cylinder and pawls (24, 25) protruding from insides of the caps (14, 15). A toner cartridge according to claim 3, characterized in that the caps (14, 15) have seals (26) around the circumference thereof at the portion where the caps are in contact with the inner surface of the outer cylinder (12). A toner cartridge according to one of the preceeding claims, characterized in that the outer cylinder (12) has cutaway portions (31) at the both end side surfaces thereof so that the inner cylinder (13) may be able to turn smoothly. A toner cartridge according to Claim 1, characterized in that a projecting elastic member (43) is provided inside the cap (14;15) to push the one circumferential end (130) of the inner cylinder, a stopper (41) which engages the other circumferential end (13b) of the inner cylinder is provided inside the outer cylinder, and further a fixing means (44,45,46) is provided to interlock the caps and the outer cylinder in turning. A toner cartridge according to Claim 6, characterized in that the projecting member (43) is integrally rigidly formed with the center of the cap at one end thereof, but is elastic at other portion thereof. A toner cartridge according to Claim 7, characterized in that the projecting member (43) is bent about 6° in the turning direction to push one circumferential end of the inner cylinder. A toner cartridge according to Claim 6, characterized in that the stopper (41) is integrally formed with the outer cylinder and substantially same in longitudinal length and same in thickness as the inner cylinder. A toner cartridge according to Claim 6, characterized in that the fixing means comprises first holes provided on the caps, second holes (44) provided on the side surface of the outer cylinder and pins (45,46) inserted through the first and second holes. A toner cartridge according to Claim 6, wherein the fixing means comprises grooves (53,54) on the side surface of the outer cylinder and projections (51,52) provided at the outer circumference of the caps at the positions corresponding to the grooves, characterized in that the projections are easily destructible. A toner cartridge according to Claim 1, characterized by a first stopper (41) which is provided on the inner surface of the outer cylinder and engages one circumferential end (13b) of the inner cylinder, a second stopper (61;62) which is provided on the inner side of the cap and engages the other circumferential end (13a) of the inner cylinder and further a biassing means (63,64) as the pressing means to turn the cap with respect to the outer cylinder. A toner cartridge according to Claim 1, characterized in that the biassing means is composed of a detachable leaf spring (63,64). A toner cartridge according to Claim 3 and 12, characterized in that the connecting means to interlock the inner cylinder and the caps when the caps are turned comprises the holes(22a-c; 23a-c) provided at the end portions of the inner cylinder, the pawls (24,25) provided on the inside of the caps and further the second stoppers (61,62), which project from the inner sides of the caps and engage one circumferential end (13a) of the inner cylinder. A toner cartridge according to Claim 13, characterized in that the leaf springs (63,64) having the same shape are provided on the caps put on both sides of the toner cartridge, wherein one ends of the leaf springs engage the longitudinal ends of the outer cylinder and the other ends thereof engage the caps.

Inventors: KIKUCHI HIROSHI, MOMIYAMA YOSHIHARU, NAKAJIMA SHIGEKI, ONO HISAO, OTA YUKIO, KIKUCHI, HIROSHI, MOMIYAMA, YOSHIHARU, NAKAJIMA, SHIGEKI, ONO, HISAO, OTA, YUKIO
Applicants: OKI ELECTRIC IND CO LTD, OKI ELECTRIC INDUSTRY COMPANY, LIMITED
Application year: 1991
Main classification: G03G15
IPC codes: G03G15