METHOD AND APPARATUS FOR LOADING / UNLOADING A DRUM MEMBER

Abstract: An apparatus for loading/unloading a drum member, and a related method. The apparatus includes an inner support member slidably (4) arranged between a center shaft (2) fixed to a frame (1, 5a, 5b) and a drum member (3). When the drum member (3) is required to be unloaded from the frame, the inner support member (4) is ejected along the center shaft (2) for a predetermined length, and then the drum member (3) is drawn out while using the inner support member (4) as a guide. The method includes the steps of: providing a center shaft (2) secured at one end (2a) to the frame (1, 5a, 5b); providing an inner support member (4) slidably attached to the center shaft (2); providing a drum member (3) supported at its inner surface by the inner support member (4) and being slidable along the center shaft axis; drawing out the inner support member (4) for a predetermined length toward the outside of the frame (5a, 5b); and drawing out the drum member (3) toward the outside of the frame (5a, 5b), while using the inner support member (4) as a guide. By this apparatus and method, the drum can be drawn out easily and safely while using the inner support member as a guide.

Description: This invention relates to a method and an apparatus for loading/unloading a drum member relative to a frame in which the drum member is used. In an electro-photographic printing apparatus or an electro-photographic copier, an electro-static latent image forming drum coated with photosensitive material is provided. In such apparatus, many associated devices such as a corona charger, a developer, pre-cleaning decharger, etc. are arranged close to the drum. Therefore, when the drum is to be loaded into or unloaded from the frame for inspections or replacement, very careful handling is required, or else the drum will be damaged by hitting these devices. Damage to the drum is also likely in a magnetic drum memory apparatus or any other apparatus including a sensitive drum member provided with associated devices in its vicinity. The drum member is usually supported by a center shaft, which is secured at one end to the frame of the apparatus. The other end of the center shaft is free or easily detachably fixed to the frame. A conventional method of loading/unloading the drum includes the steps of connecting a separate tool such as an extension rod to the free end of the center shaft for elongating or extending the center shaft, and drawing out the drum while guiding the drum along the extension rod. Another prior art method, as shown in Japanese patent publication Tokkosho 60-15942 (JP-B2-60-15942), includes the steps of providing a center shaft made as a pipe, providing a special rod having a length longer than the length of the drum, inserting the rod into the center shaft pipe, securing one end of the rod to the frame, detaching the center shaft, and then drawing out both the drum and center shaft together. In either prior art method, a special tool, such as the extension rod, must be provided and also a space for housing this tool must be provided in the frame. Therefore, the size of the frame becomes undesirably larger. Furthermore, a maintenance person is required to expend much labor to attach and detach the tool every time the drum is loaded/unloaded. In addition, such electro-photographic apparatus is generally provided with an electric power switch which co-operates with the opening/closing of a front door thereof so that the power supply is cut when the door is opened. In the case where the tool is housed within the frame, and a maintenance person forgets to store the tool in the frame, the front door must be opened once again, and restarting the apparatus is undesirably delayed. This delay includes not only the time required for opening and closing the door, but also warm-up time. US-A-4 527 883 discloses a mounting structure for a cylindrical photosensitive member. The cylindrical member is mounted on or dismounted from a central support shaft using guide members interposed between the cylindrical member and the shaft. The central support shaft is rotatably supported at one end on a part of a frame, and the cylindrical member when mounted is housed between that part of the frame and another part of the frame at the other end of the central support shaft, beyond which the central support shaft extends. The guide members comprise hubs, fitted over and axially movable on the shaft, with guide vanes radiating from the hubs to resiliently engage the inner surface of the cylindrical member. When the cylindrical member is to be dismounted, the guide members, initially spaced apart, move axially along the shaft as the cylindrical member is drawn off the shaft. The movements of the guide members are limited and when the guide members reach the limits of their movements, the internal surface of the cylindrical member slides over the vanes of the guide members to allow further withdrawal and dismounting of the cylindrical member. An embodiment of this invention can provide a method and an apparatus for loading/unloading a drum member relative to a frame easily and without substantial labour. An embodiment of this invention can provide a method and an apparatus for loading/unloading a drum member relative to a frame without requiring extra space for housing a tool in the frame. According to the present invention there is provided an apparatus for loading/unloading a drum member relative to a frame in which the drum member is used, comprising:- a centre shaft secured at a first end to a part of the frame, the drum member when loaded being housed between the said part of the frame and another part of the frame at the other, second end of the centre shaft, an inner support member, attached to the centre shaft to be slidable in the direction of the centre shaft axis while being guided by the centre shaft, between the centre shaft and the drum member, for supporting the drum member, the drum member being slidable on the inner support member in the direction of the centre shaft axis, characterised in that the inner support member is cylindrical, having a cylindrical outer surface and an outer diameter substantially the same as the inner diameter of the drum member, such that the cylindrical outer surface of the inner support member can support and guide the drum member while the inner support member slides in the direction of the centre shaft axis during unloading of the drum member, until an end portion of the drum member projects beyond the part of the frame at said second end of the centre shaft, and the drum member can then slide in the direction of the centre shaft axis on the cylindrical outer surface of the inner support member, being supported and guided by the inner support member. According to the present invention there is provided a method for loading/unloading a drum member relative to a frame in which the drum member is used, comprising:- providing a centre shaft secured at a first end to a part of the frame, the drum member when loaded being housed between the said part of the frame and another part of the frame at the other, second end of the centre shaft, providing an inner support member, attached to the centre shaft to be slidable in the direction of the centre shaft axis while being guided by the centre shaft, between the centre shaft and the drum member, for supporting the drum member, providing the drum member to be slidable on the inner support member in the direction of the centre shaft axis, providing as inner support member a cylindrical inner support member, having a cylindrical outer surface and an outer diameter substantially the same as the inner diameter of the drum member, and drawing out the inner support member for a predetermined length towards the second end of the shaft, the cylindrical outer surface of the inner support member supporting and guiding the drum member while the inner support member slides in the direction of the centre shaft axis during unloading of the drum member, until an end portion of the drum member projects beyond the part of the frame at said second end of the centre shaft, drawing out the drum member, the drum member sliding in the direction of the centre shaft axis on the cylindrical outer surface of the inner support member, being supported and guided by the inner support member, to the outside of the frame. According to this apparatus and method, the drum can be drawn out easily and safely by using the inner support member as a guide. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention. FIG. 1A is a cross-sectional view showing apparatus of the present invention with the drum loaded according to the present invention. FIG. 1B is a cross-sectional view showing the drum being unloaded according to the present invention. FIG. 1C is a cross-sectional view showing a final step in the unloading of the drum according to the present invention. FIG. 2 is a partial cross-sectional view of a first embodiment of an electro-photographic apparatus according to the present invention. FIG. 3 is a partially enlarged cross-sectional view of the electro-photographic apparatus shown in FIG. 2. FIG. 4A is a partial side view of one end of the center shaft of the embodiment shown in FIG. 2. FIG. 4B is a flattened circumferential view of FIG. 4A. FIG. 5 is a partially enlarged cross-sectional view of a drive flange of the embodiment shown in FIG. 2. FIG. 6 is a partial perspective view of an inner support member of the embodiment shown in FIG. 2. FIG. 7 is a partial cross-sectional view of a second embodiment of an electro-photographic apparatus according to the present invention. FIG. 8 is a partially enlarged cross-sectional view of a third embodiment of an electro-photographic apparatus according to the present invention. FIG. 9 is a partially enlarged cross-sectional view of a fourth embodiment of an electro-photographic apparatus according to the present invention. FIGS. 1A-1C illustrate generally the present invention, including: a center shaft 2 is secured at a first end 2a to a portion of the frame 1, an inner support member 4 is attached to the center shaft 2 such that it is slidable in the direction of the axis of the center shaft 2 as indicated by an arrow BA; and a drum 3, having an inner diameter substantially the same as the outer diameter of the inner support member 4. Members 5a and 5b are parts of the front of the frame 1 of the apparatus. When the apparatus is in operation, both the inner support member 4 and the drum 3 are housed within the frame 1 as shown in FIG. 1A. When the drum 3 is required to be unloaded, the inner support member 4 and the drum 3 are drawn out in the direction A for a predetermined length, as shown in FIG. 1B, and then the drum 3 is further drawn out in the direction A, while using the inner support member 4 as a guide, as shown in FIG. 1C. When re-loading of the drum 3 is required, the reverse steps are followed. FIG. 2 shows a partial, cross-sectional elevational view of a first embodiment of the present invention. A center shaft 11 is secured at a first end 11a to a part 12a of the frame 12, and detachably secured at its second, opposite end 11b to the front 12b of the frame via a cover assembly 14. An inner support member 18 is attached to the center shaft 11 via flanges 18a and 18d thereof and is slidable in the direction of the axis of the center shaft 11 as indicated by an arrow CE. A coil spring 21 is provided on the center shaft 11, between a stopper 19 secured to the center shaft by a screw 20 and the flange 18a, so that the spring 21 forces the inner support member 18 toward the outside of the frame 12, namely in the direction indicated by arrow G. The outer diameter of the inner support member 18 is almost equal to the inner diameter of a drum member 10 so that the outer surface 18f of the inner support member 18 can support and guide the inner surface 10b of the drum member 10. This drum member 10 is, for example, a latent image developing drum for an electro-photographic printing apparatus, coated with a photosensitive material at its outer surface. Many associated known devices required to develop the latent image, such as a corona charger, a toner developer device, an optical system, a preclean corona decharger etc., are omitted from the figure for simplicity and convenience. When rotated in operation, the drum member 10 is sandwiched and supported between a drive flange 13 and a support flange 15. The drive flange 13, as shown more in detail in FIG. 5, has a tapered rim 13b and a timing gear 13c. The rim 13b is partially inserted into a first end 10c of the drum member 10. The timing gear 13c is connected to a timing gear 41 of a motor 40 via a timing belt 36. The drive flange 13 is rotatable around the center shaft 11 by means of bearings 34 and 35. The support flange 15 is a part of the cover assembly 14, as shown more in detail in FIG. 3. The cover assembly 14 consists of: a sleeve 25 having an inner diameter substantially the same as the outer diameter of the center shaft 11; the support flange 15 provided at a first end 25a of the sleeve 25 with a bearing 24; a coil spring 17 provided between the support flange 15 and a stopper washer 29 for forcing the support flange 15 toward the first end, namely in the direction C of the arrow CE; a stopper pin 28 pierced through the sleeve 25; a knob 27 secured at the second end of the sleeve 25; and a cover plate 16 for covering an aperture 23 (FIG. 2) of the front 12b of the frame 12 for drawing the drum member 10 outside the fame 12. The cover plate 16 has one or more positioning holes 16a which receive respective positioning pins 12c of the frame 12. Furthermore, a coil spring 32 is provided on the sleeve 25 between the cover plate 16 and the knob 27 for forcing the cover plate 16 in the direction C of the arrow CE. Members 26a, 26b and 33 are washers working as stoppers. A tapered rim 15a of the support flange 15 is partially inserted into the second end 10a of the drum member 10. The center shaft 11 in this embodiment is a pipe at the second, free end 11b of which there is provided a pair of grooves 31, each having an open portion 31a and a closed portion 31b. The width of the groove 31 is substantially the same as the diameter of the stopper pin 28. FIG. 4A shows a side view of the second end 11b of the center shaft 11 including the groove 31. FIG. 4B shows a flattened view of the circumferential structure of the grooves 31. The groove 31 and the stopper pin 28 form a lock means. The unloading operation will be explained by referring to Figs. 2, 3 and 4. (1) First, by the user pushing the knob 27 in the direction C and then rotating the knob 27 counterclockwise, namely the direction D of the arrow DF, both ends 28a and 28b of the stopper pin 28 are guided along the grooves 31 toward the open portion 31a, and the cover assembly 14 is unlocked from the center shaft 11. (2) By drawing out the knob 27 in the direction E, the whole cover assembly 14 is removed from the apparatus. (3) By then removing the sleeve 25 and the support flange 15, the inner support member 18 is pushed out in the direction E by the spring 21 and ejected outside the frame 12 a predetermined length, as shown by a dotted line 18e in FIG. 2, which length can be defined by the position of a stopper screw 22. At the same time, the drum member 10 is also disengaged from the support flange 15, and may be moved with the inner support member 18 due to the friction between them. (4) Then, the drum member 10 can be further drawn out in the direction E by using the ejected inner support member 18 as a guide means without hitting peripheral devices, because the end of the inner support member 18 is ejected outside of the part 12b of the frame 12. (5) For re-loading the drum member 10 after it is cleaned, or for loading a new drum member 10, the reverse procedure is carried out. Namely, the drum member 10 is guided by and engaged with the inner support member 18 positioned outside the frame. (6) Then, while pushing the inner support member 18, together with the drum member 10, inside the frame 12 against the force of the spring 21, the cover assembly 14 is attached to the center shaft 11. (7) While engaging the stopper pin 28 with the open portion 31a of the groove 31 of the center shaft 11, the cover assembly 14 together with the inner support member 18 and the drum member 10 is further pushed inside while the user rotates the knob 27 in a clockwise direction. Upon hitting the closed portion 31b, the user releases the knob 27, the cover assembly 14 is locked to the center shaft 11, and the drum member 10 is supported between the drive and support flanges, 13 and 15, respectively. (8) By engaging each positioning hole 16a with each positioning pin 12c, the cover plate 16 is positioned and secured to the frame 12 by the spring 32. The inner support member 18 also can be removed from the center shaft 11, since the flange 18a has a recess 18c, as shown in FIG. 6, for clearing the stopper screw 22. The diameter of an aperture 18b of the flange 18a is substantially the same as the outer diameter of the center shaft 11. To ensure the stopper function of the stopper screw 22, the inner support member 18 must be rotated, preferably 180°, after being inserted on the center shaft 11. The length of the center shaft 11 is substantially the same as the length of the drum member 10 in the above embodiment, but this is not necessarily required. For example, the center shaft 11 may be shorter than the drum member 10 if the sleeve 25 of the cover assembly 14 is long enough, and still the inner support member 18 can be ejected as its second end comes outside the front 12b of the frame 12. In any case, in order to guide the drum member 10 outside of the front 12b, the total length of the center shaft 11 and the inner support member 18 must be longer than the length of the drum member 10. In the above embodiment, the inner support member 18 is a dummy drum which has no function during normal operation of the apparatus. But this inner support member 18 can be used as a heater drum for eliminating any non-uniformity of the temperature of the drum member 10. FIG. 7 shows such a heater drum 50, wherein similar reference numerals represent the similar parts shown in FIG. 2. The heater drum 50 has a heater winding 51 at its inner surface, and lead wires 53 extending through the inside of the center shaft 11 via a hole 11c and a connector 52. The drive flange 13 of the first embodiment is described as being driven by the timing belt 36, but this is not necessarily required. For example, a series of gears can be used instead of the timing belt. In such a case, the drive flange can be integrated with the inner support member as shown in FIG. 8. In this figure, 60 is an integrated inner support member having an inner drum portion 61 and a drive flange portion 62. The drive flange portion 62 has a gear portion 62c and bearings 65 and 66. An intermediate gear 63 is provided between the center shaft 11 and the motor 40, supported by a bearing 64. The gear 63 has two gear portions 63a and 63b. The edges of both the gear portions 63b and 62c are tapered so that they can be easily reengaged when the disengaged inner support member 60 is pushed back in the direction shown by arrow H upon reloading of the drum member 10. The remaining members not shown in FIG. 8 are substantially the same as in FIG. 2. When the drum member 10 is required to be unloaded, the drum member 10 and the inner support member 60 are simultaneously drawn out for a predetermined length, and then only the drum member 10 is further drawn out by using the inner drum portion 61 as a guide means. Furthermore, as shown in FIG. 9, a flange portion 10d at the outside of the drum member 10 and a coil spring 70 between this flange 10d and the flange 18d of the inner support member 18 can be provided, so that the drum member 10 is pushed out simultaneously as the inner support member is pushed out by the spring 21, when the cover assembly 14 is removed. The inner support member 18 is in the form of a drum, namely it is cylindrical, with a cylindrical outer surface. Furthermore, it is also possible to provide an inner support member as a sleeve having an outer diameter close to the outer diameter of the center shaft 11, rather than close to the outer diameter of the drum member 10 as in the case of FIG. 2, and to provide a drum member with flanges having an inner diameter substantially the same as the outer diameter of the sleeve.

Claims: An apparatus for loading/unloading a drum member (3; 10) relative to a frame (1, 5a, 5b; 12a, 12b) in which the drum member is used, comprising:- a centre shaft (2; 11) secured at a first end to a part (12a) of the frame, the drum member (3; 10) when loaded being housed between the said part (12a) of the frame and another part (5a, 5b; 12b) of the frame at the other, second end of the centre shaft, an inner support member (4; 18; 50; 60), attached to the centre shaft (2; 11) to be slidable in the direction of the centre shaft axis while being guided by the centre shaft (2; 11), between the centre shaft (2; 11) and the drum member (3; 10), for supporting the drum member (3; 10), the drum member (3; 10) being slidable on the inner support member (4; 18; 50; 60) in the direction of the centre shaft axis, characterised in that the inner support member (4; 18; 50; 60) is cylindrical, having a cylindrical outer surface and an outer diameter substantially the same as the inner diameter of the drum member (3; 10), such that the cylindrical outer surface of the inner support member (4; 18; 50; 60) can support and guide the drum member (3; 10) while the inner support member (4; 18; 50; 60) slides in the direction of the centre shaft axis during unloading of the drum member (3; 10), until an end portion of the drum member (3; 10) projects beyond the part (5a, 5b; 12b) of the frame at said second end of the centre shaft, and the drum member (3; 10) can then slide in the direction of the centre shaft axis on the cylindrical outer surface of the inner support member (4; 18; 50; 60), being supported and guided by the inner support member. The apparatus of claim 1, wherein the length of the centre shaft (11) is less than the distance between the two said parts (12a, 12b) of the frame. The apparatus of claim 1 or 2, wherein the inner support member (4; 18; 50; 60) is an inner drum whose outer diameter is substantially the same as the inner diameter of the drum member (3; 10). The apparatus of claim 1 or 2, wherein the inner support member is a sleeve having an outer diameter close to the outer diameter of the centre shaft (11), and the drum member (10) is provided with flanges having an inner diameter substantially the same as the outer diameter of the sleeve. The apparatus of claim 3, further comprising:- (a) a first flange member (13; 62) rotatably provided at the first end of the centre shaft (11), having an outer diameter greater than the inner diameter of the drum member (10); (b) a second flange member (15) rotatably and detachably provided at the second end of the centre shaft (11), having an outer diameter greater than the inner diameter of the drum member (10); and (c) first means (17), provided at the second end of the centre shaft (11), for forcing the second flange member (15) toward the first flange member (13, 62); whereby the drum member (10) is sandwiched and supported between the first (13; 62) and the second (15) flange members, and the inner drum (18; 50; 60) is placed inside of the drum member (10) and between the first (13; 62) and the second (15) flange members. The apparatus of claim 5, further comprising:- (a) second means (21), provided on the centre shaft (11), for forcing the inner drum (18; 50; 60) toward the second flange member (15), whereby, by detaching the second flange member (15), the inner drum (18; 50; 60) is ejected in a direction away from the first end of the centre shaft (11) for a predetermined length. The apparatus of any preceding claim, wherein the drum member (10) is a photosensitive latent image forming drum. The apparatus of claim 3, 5 or 6, wherein the drum member (10) is a photosensitive latent image forming drum, and the inner drum (50) is provided with an inner surface including a heater winding (51). The apparatus of claim 5 or 6, or of claim 7 or 8 read as appended to claim 5 or 6, wherein the first flange member (62) is formed integrally with the inner drum (60) inseparably. The apparatus of claim 6, or of claim 7, 8 or 9 when read as appended to claim 6, further comprising:- (a) a third means (70), provided between the inner drum and the drum member (10), for forcing the drum member (10) towards the second flange member (15), whereby, by detaching the second flange member (15), the drum member (10) is also ejected in a direction away from the first end of the centre shaft (11). The apparatus of claim 5, or of any one of claims 6 to 10 when read as appended to claim 5, further comprising:- (a) means (31, 28) provided at the second end of the centre shaft (11), for detachably locking the second flange (15) to the centre shaft (11). The apparatus of any preceding claim, wherein the length of the centre shaft (11; 2) is substantially equal to or shorter than the length of the drum member (10; 3), and the length of the inner support member (4; 18; 50; 60) is substantially equal to or shorter than the length of the drum member (10; 3). A method for loading/unloading a drum member (3; 10) relative to a frame (1, 5a, 5b; 12a, 12b) in which the drum member is used, comprising:- providing a centre shaft (2; 11) secured at a first end to a part (12a) of the frame, the drum member (3; 10) when loaded being housed between the said part (12a) of the frame and another part (5a, 5b; 12b) of the frame at the other, second end of the centre shaft, providing an inner support member (4; 18; 50; 60), attached to the centre shaft (2; 11) to be slidable in the direction of the centre shaft axis while being guided by the centre shaft (2; 11), between the centre shaft (2; 11) and the drum member (3; 10), for supporting the drum member (3; 10), providing the drum member (3; 10) to be slidable on the inner support member (4; 18; 50; 60) in the direction of the centre shaft axis, providing as inner support member (4; 18; 50; 60) a cylindrical inner support member, having a cylindrical outer surface and an outer diameter substantially the same as the inner diameter of the drum member (3; 10), drawing out the inner support member (4; 18; 50; 60) for a predetermined length towards the second end of the shaft, the cylindrical outer surface of the inner support member (4; 18; 50; 60) supporting and guiding the drum member (3; 10) while the inner support member (4; 18; 50; 60) slides in the direction of the centre shaft axis during unloading of the drum member (3; 10), until an end portion of the drum member (3; 10) projects beyond the part (5a, 5b; 12b) of the frame at said second end of the centre shaft, and drawing out the drum member (3; 10), the drum member (3; 10) sliding in the direction of the centre shaft axis on the cylindrical outer surface of the inner support member (4; 18; 50; 60), being supported and guided by the inner support member, to the outside of the frame. The method of claim 13, wherein means (31, 28) are provided for locking the drum member (3; 10) and the inner support member (4; 18; 50; 60) against axial movement along the centre shaft (2; 11), the locking means being unlocked prior to the drawing out of the inner support member (4; 18; 50; 60) and the drum member (3; 10). A method as claimed in either of claims 13 and 14, the length of the centre shaft (2; 11) being substantially equal to or shorter than the length of the drum member (10; 3), and the length of the inner support member (4; 18; 50; 60) being substantially equal to or shorter than the length of the drum member (10; 3). Apparatus, as claimed in any one of claims 1 to 12, in an electrostatic photographic apparatus, the drum member (3; 10) being a hollow, latent image forming drum coated on an outer surface thereof with photosensitive material.

Inventors: IKUTA, HIROTOSHI FUJITSU LTD PATENT DEPARTMENT, TAKAYAMA, AKIRA FUJITSU LTD PATENT DEPARTMENT
Applicants: FUJITSU LIMITED
Application year: 1987
Main classification: G03G15
IPC codes: G03G21, G03G15