Abstract:
A rotator mechanism has a frame, a rotating member and a bearing. The rotating member has a center rod and is rotatable along its axis. The bearing has a bearing portion for supporting the center rod, and a clasping portion for elastically clasping onto the frame. In assembly, first the center rod of the rotating member is positioned into the bearing portion of the bearing. Then, the clasping portion of the bearing is made to elastically clasp onto the frame, whereby the bearing is firmly attached to the frame. In disassembly, the rotating member is easily removed from the frame by detaching the clasping portion from the frame. The rotator mechanism can be applied in a sorter of an image forming apparatus.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a bearing in an associated mechanism. More specifically, it relates to a bearing and a mechanism which is located in a frame for rotative support of a rotating member. 
     An image forming apparatus such as a copying machine includes a plurality of rollers for supplying/discharging sheets of paper. Each of the rollers has an axis the ends of which are rotatively supported in the body of the apparatus. The rollers may be set into a frame in the apparatus by one of the following methods, for example: 
     (i) By fitting bearings into elliptic holes formed in the frame, and inserting the ends of the center rods of the rollers into the bearings, then affixing E-rings to the ends of the rods. (See Japanese Patent Laying-Open No. 171751/1986); and 
     (ii) By fitting bearings onto the ends of the rods of the rollers, and insert the bearings into slant notches formed in the frame. 
     In conventional method (i), E-rings must be fit onto each of the ends of the roller rods, whereby joining the rollers into the frame during assembly becomes more complex as the number of the rods increases. Furthermore, when rollers must be replaced during maintenance, these many E-rings must be removed and then reattached afterwards, thereby complicating the maintenance as well. 
     In conventional method (ii), since the bearings at the ends of the rod are merely set into the notches of the frame, the rod and the roller may easily dislodge from the frame and drop, due to, for example, vibration. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a bearing in a rotator mechanism which simplifies assembly and maintenance and prevents rotating member slippage. 
     A rotator mechanism according to an aspect of the present invention has a frame, a rotating member and a bearing. The rotating member has a center rod and is capable of rotating on its axis. The bearing has a bearing portion supporting the center rod, and a clasping portion which elastically clasps onto the frame. 
     A bearing, according to another aspect of the present invention, is for supporting the center rod of a rotating member and is detachably attached to a frame. It has a center rod bearing portion and a clasping portion which elastically clasps onto the frame. 
     In assembly, the center rod of the rotating member is first positioned into the bearing portion of the bearing. Then the clasping portion of the bearing is elastically clasped onto the frame, becoming firmly attached. In disassembly, the rotating member is easily removed from the frame by detaching the clasping portion from the frame. 
     Thus, assembly and disassembly may be performed with ease. Additionally, since the bearing member is elastically clasped onto the frame, slippage of the rotating member is prevented. 
     These and other objects and advantages of the present invention will be more fully apparent from the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic sectional view showing a copying machine including an embodiment according to the present invention; 
     FIG. 2 is a schematic sectional view showing a sorter including an embodiment according to the present invention; 
     FIG. 3 is an enlarged partial view of the sorter corresponding to a sectional view taken along the line III--III of FIG. 4; 
     FIG. 4 is a sectional view taken along the line IV--IV of FIG. 3; 
     FIG. 5 is an enlarged partial isometric view of an embodiment of the present invention; and 
     FIG. 6 is an exploded perspective view of the portion shown in FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a copying machine including an embodiment of the present invention. 
     Referring to FIG. 1, the body 1 of the copying machine has a contact glass 2 in the upper surface, and an original holder 3 which can be opened is disposed on the contact glass 2. On the right side of the body 1 in the figure, a bypass tray 4 and a pair of paper cassette cases 5 and 6 are detachably attached. On the left side of the body 1, a sorter 7 including an embodiment of the present invention is disposed. 
     In the body 1, an optical exposure system 8 for obtaining information from the original image is located in the upper portion. The exposure system 8 consists of a light source, mirrors and lenses. Disposed in the central part of a lower portion of the body 1 is a photoconductive drum 9 on which an electrostatic image is formed. Surrounding the photoconductive drum 9, there are a main charger 10 for charging the photoconductive drum 9 with a predetermined level of electric charge, a developing unit 11 for developing an electrostatic image, a transfer unit 12 for transferring a toner image to paper, a detach unit 13 for detaching paper from the photoconductive drum 9 , and a cleaning unit 14 for removing toner from the photoconductive drum 9, in that order. 
     A paper transporting path 17 extends from the bypass tray 4 and the paper cassette cases 5 and 6 to the image forming part which includes the photoconductive drum 9. A paper discharging path 18 is provided in a part of the paper flow stream beyond the image forming part. At the ends of the paper cassette cases 5 and 6 near the paper transporting path 17, feeding rollers 16a and 16b are provided to feed singly sheets of paper to the paper transporting path 17. A fixing unit 20 for fixing a transferred image onto the fed paper, and discharging rollers 19 for discharging the fixed paper to the sorter 7, are disposed between the paper discharging path 18 and the sorter 7. 
     The sorter 7 has a receiving path 29 for receiving paper from the discharging rollers 19, a plurality (for example, eleven) of bins 30a and 30b in a vertically-gapped arrangement, and a delivering mechanism 31 disposed between the receiving path 29 and the bins 30a and 30b. The bins 30a and 30b consist of non-sorting bin 30a above and sorting bins 30b below. 
     Referring to FIG. 2, the delivering mechanism 31 has a large-type roller 32 in the upper portion and another large-type roller 33 in the lower portion. The lower roller 33 is connected with a driving mechanism (not shown). Guide belts 34 extend around the large-type rollers 32 and 33. A plurality of discharging rollers 35 correspond with the sorting bins 30b in the vicinity of the bases of the bins 30b. Each discharging roller 35 is pressed onto the outer surface of the guide belts 34 which face the bins 30b. The discharging rollers 35 are rotatively supported by a case 7a of the sorter 7. 
     Referring to FIG. 3, sorting claws 36 are provided under the discharging rollers 35. Each sorting claw 36 is connected to a solenoid mechanism (not shown) which is operable independently of the others, whereby the sorting claw 36 is shifted between the sorting position, as shown at the top in FIG. 3 and the non-sorting position, as shown at the bottom. Furthermore, a wall 7b of the sorter 7 has openings 37 to allow a sheet of paper to pass through from the pairs of the discharging rollers 35 and the sorting claws 36 to the bins 30b. 
     Referring to FIG. 2, an opening 50 to allow paper to pass through is provided above the base of the non-sorting bin 30a, and a pair of discharging rollers 51 are provided before the opening 50. Located between the rollers 51 and the receiving path 29 is a pressing roller 52, which presses onto the large-type roller 32 through the guide belts 34, and a switching claw 53 for changing the direction of paper transfer. The switching claw 53 is connected with a solenoid mechanism (not shown) whereby the claw 53 is shifted between one transferring position, for transferring paper toward the sorting bins 30b, and another transferring position (not shown), for transferring paper toward the non-sorting bin 30a. Provided under the switching claw 53 is a guide plate 54 extending toward the uppermost discharging roller 35 along the guide belts 34 at a specific gap. The lowermost discharging roller 35 has no corresponding sorting claw; rather, it has a fixed guide plate 55. 
     The portion of the delivering mechanism 31 in which the present invention is applied will be described in detail. 
     Four guide holders 40 are disposed inside the guide belts 34 of which one couple is aligned vertically, as shown in FIG. 2, and of which the second couple is aligned horizontally, as shown in FIG. 4. The guide holders 40 are made of metal plates. Against the back side (or right side in FIG. 2) of each guide holder 40 are pressing mechanisms 41. The pressing mechanisms 41 are disposed at the four corners of each guide holder 41. As shown in FIG. 4, the pressing mechanisms 41 are connected to stays 42 which extend horizontally and are fixed at their ends to the case 7a. Each of the pressing mechanisms 41 has a stud pin 43 one end of which is fixed into the stay 42, standing it on the stay 42 at a right angle extending horizontally. The stud pin 43 has a head at the other end. The middle portion of the stud pin 43 is slidably inserted into a hole 44 formed in a side portion of the guide holder 40. Coil springs 45 are fitted onto the stud pins 43 in compression between the guide holders 40 and the stays 42. The coil springs 45 push the guide holders 40 toward the discharging rollers 35. The guide holders 40 include roller housings 46 having holes 44 in either end. The roller housings 46 contain guide rollers 47 which face against the discharging rollers 35 through the guide belts 34. 
     Each pair of the guide rollers 47 has a center rod 48; and at the ends of the rod 48, bearings 60 according to the present invention are provided. The bearings 60 are made of polyacetal resin, and, as shown in FIGS. 5 and 6, consist of a bearing portion 61 rotatively supporting the center rod 48, and a clasping portion 62 integral with the bearing portion 61. 
     The bearing portion 61 has a hole 61a into which the center rod 48 is inserted. The bearing portion 61 is fitted into a U-shaped notch 49 formed in the roller housing 46. The bearing portion 61 includes a pair of flat surfaces 61b in parallel on its circumferential rim, and the flat surfaces 61b contact a pair of inner flat surfaces of the notch 49. Additionally, the bearing portion 61 has a flange portion 63 which contacts the inner surface (or the posterior surface in FIGS. 5 and 6) of lateral wall 46a of the roller housing 46. As shown in FIG. 6, the flange portion 63 extends radially from both of the flat surfaces 61b. 
     The clasping portion 62 extends from the bearing portion 61 along the lateral wall 46a. The clasping portion 62 has, at its end, a turned portion 62a at approximately a right angle. At the tip of the turned portion 62a, a bevel surface 62c is provided in order to ease the operation of engaging the bearing 60. Furthermore, the roller housing 46 has an opening 64 extending from the lateral wall 46a to the base wall 46b, in the region beyond the notch 49. The turned portion 62a clasps onto a tab 65 of a catch portion in the opening 64. As a result, the bearing 60 nips the lateral wall 46a by means of the flange 63 and the clasping portion 62, whereby the bearing 60 is fixed into the notch 49 properly. In order to facilitate the operation of detaching the bearing 60, the tab 65 projects slightly from the surface of the base wall 46b. 
     When the center rod 48 and the bearing 60 as shown disassembled in FIG. 6 are to be assembled into the guide holder 40 as shown in FIG. 5, first the center rod 48 is inserted into the hole 61a of the bearing 60. Then, the bearing portion 61 of the bearing 60 is fitted into the notch 49 of the roller housing 46. At the same time, the turned portion 62a of the clasping portion 62 is elastically bent and then is clasped onto the projected tab 65 of the roller housing 46, whereby the rod 48 and the roller 47 are properly set. 
     Thus, the assembly operation is made simpler because the rod 48 and the roller 47 may, without a conventional E-ring, be easily set. Furthermore, since the bearing 60 elastically clasps onto the roller housing 46 by means of its clasping portion 62, the bearing 60 is tenaciously attached, without being susceptible to dislocation due to vibration. When the rod 48 and the roller 47 are disassembled in maintenance, the disassembling can be carried out easily by removing the turned portion 62a from the projected tab 65 with a finger. The opening 64 is formed, and the projected tab 65 projects beyond the base wall 46b, such that it is easy to hook the turned portion 62a with a finger in the disassembling operation. 
     Since the copying operation of the above described copying machine is not out of the ordinary, the operation is briefly described in the following, in lieu of a detailed description. The position of the switching claw 53 is shifted depending upon whether the set mode is in the non-sorting mode or the sorting mode. When the non-sorting mode is set, sheets of paper are transferred from the receiving path 29 through the discharging rollers 51 and the opening 50 to the bin 30a. When the sorting mode is set, sheets of paper are guided by the guide belts 34 and transferred to predetermined bins 30b through sorting claws 36 which have been positioned to correlate with the sorting number. 
     Modifications 
     (a) The present invention can be applied not only to image forming apparatuses, such as copying machines, but also to other apparatuses which include rotating elements. 
     (b) The present invention is not limited by the above embodiment in which the center rods 48 are rotatively supported by the bearings 61. For example, the rollers 47 may be rotatively supported by the center rods 48, and the center rods 48 may be fixed to the bearings 61. 
     Various details of the invention may be changed without departing from its spirit nor its scope. Furthermore, the foregoing description of the embodiments according to the present invention is provided for the purpose of illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.