Abstract:
A paper roll supporting device for an image forming apparatus includes a pair of flange members to be inserted into opposite ends of a paper roll. Each flange member includes a flange body made up of a flange portion and a cylindrical support portion that is to be inserted into a tubular core included in the paper roll. A claw member has a plurality of claws capable of protruding from the outer circumference of the support portion. A biasing member exerts a pressure on the claw member. Pressing means is slidable in a direction in which the biasing member is compressible. The pressing means receives one end of the biasing member and contacts the inner circumference of the support portion. A lock/release lever is capable of being brought down for causing the pressing means to slide. The claw member causes its pawls to flare in the radial direction when pressed in the axial direction of the support portion. The device with this configuration can be easily locked to the paper roll.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a printer, copier, facsimile apparatus or similar image forming apparatus including a paper feeding mechanism, and more particularly to a paper roll supporting device for supporting a paper roll applicable to the image forming apparatus. 
     It is a common practice with an image forming apparatus to set a paper roll by use of a spool type of member. This kind of scheme allows a paper roll to be supported over its entire width and allows a spool to be directly positioned by opposite side walls of the apparatus. The paper roll therefore shakes little and is easy to transport. However, in a large-scale machine capable of dealing with paper of up to size AO, the spool is as long as 1 m and makes the attachment and detachment of a paper roll difficult. For this reason, the spool scheme is not feasible for a large-scale machine. 
     On the other hand, Japanese Utility Model Laid-Open Publication No. 64-43048 and Japanese Utility Model Publication No. 7-48598 each propose to fit flanges in opposite ends of a paper roll and position the flanges on rollers. Specifically, Laid-Open Publication No. 64-43048 discloses a paper roll supporting device including a support wheel, a nut, and a screw. The support wheel includes a cylindrical portion whose outside diameter is slightly smaller than the inside diameter of an axial center bore formed in a paper roll. A plurality of axial slits are formed in the circumferential wall of the cylindrical portion. A flared flange extends out from one end of the cylindrical portion. The nut has a conical pressing surface contacting the inner periphery of the open end of the cylindrical portion. The screw connects the nut to the support wheel. The screw presses the inner wall of the tubular core of the paper roll via the flange, exerting a great retaining force. This kind of device, however, forces the operator to drive the screw and perform other troublesome operations at the time of setting. 
     On the other hand, Publication No. 7-48598 teaches a paper roller supporting device including a body member to be inserted into the core of a paper roll an end support member that supports the paper roll. An auxiliary member is inserted in a through hole formed in the body member. A plurality of arm members protrude from the body member in the direction in which the end support member is to be inserted into the core. A lug protrudes from each arm member toward the wall of the through hole. The auxiliary member includes a tubular portion to be received in the through hole of the body member. Lug members protrude from the outer circumference of the tubular member, and each is formed with a recess at its top. When the auxiliary member is inserted into the body member and rotated bout is own axis, the lugs of the arm members mate with the recesses of the lug members while the arm members flare and press the inner periphery of the core. This kind of configuration effectively presses the inner periphery of the core by using an elastic force available with resin. However, because the cylindrical member is rotated to elastically deform the resin members with the lugs, the body member itself rotates together with the cylindrical member unless the operator holds the flange. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a paper roll supporting device for an image forming apparatus including improved flanges for promoting easy setting operation. 
     A paper roll supporting device for an image forming apparatus of the present invention includes a pair of flange members to be inserted into opposite ends of a paper roll. Each flange member includes a flange body made up of a flange portion and a cylindrical support portion that is to be inserted into a tubular core included in the paper roll. A claw member has a plurality of claws capable of protruding from the outer circumference of the support portion. A biasing member exerts a pressure on the claw member. Pressing means is slidable in a direction in which the biasing member is compressible. The pressing means receives one end of the biasing member and contacts the inner circumference of the support portion. A lock/release lever is capable of being brought down for causing the pressing means to slide. The claw member causes its pawls to flare in the radial direction when pressed in the axial direction of the support portion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which: 
     FIG. 1 is a view showing the general construction of an image forming apparatus including a paper roll supporting device embodying the present invention; 
     FIG. 2 is an isometric view showing the paper roll supporting device; 
     FIG. 3 is a side elevation showing a paper roll set by the paper roll supporting device; 
     FIG. 4 is an exploded view of a flange member forming part of the paper roll supporting device; 
     FIG. 5 is a view showing the flange member locked to the paper roll; 
     FIG. 6 is a view showing the flange member unlocked from the paper roll; 
     FIG. 7 is an isometric view showing the end face of the flange with a lock/release lever being brought down to a locking position; 
     FIG. 8 is an isometric view showing the end face of the flange with the lock/release lever being raised to an unlocking position; and 
     FIG. 9 is a view showing a modified form of the lock/release lever. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1 of the drawings, an image forming apparatus including a paper roll supporting device embodying the present invention is shown and implemented as a copier by way of example. The copier includes a paper tray, not shown, which is movable into and out of a copier body by hand. As shown, a plurality of paper rolls  1  are set from the above or from the front (left-hand side in FIG. 1) after the paper tray has been pulled out of the copier body. Feed roller pairs  2  each convey paper paid out from a particular paper roll  1  toward an image forming section. Paper conveyance paths extending from the roller pairs  2  join each other at a position short of a cutter  3 . The cutter  3  cuts each paper at a preselected length necessary for image formation. As a result, a sheet cut off by the cutter  3  is delivered toward the image forming section. 
     A registration roller pair  4  drives the sheet at a preselected timing synchronous to an image forming timing. An image transfer section  5  includes a photoconductive element and transfers a toner image from the photoconductive element to the sheet. A fixing section  6  fixes the toner image transferred to the sheet. The sheet coming out of the fixing section  6  is driven out of the copier body. On the other hand, a scanning section  7  conveys a document and reads image information out of the document. The photoconductive element is exposed imagewise in accordance with the image data output from the scanning section  7 . 
     FIG. 2 is an exploded view showing how one of the paper rolls  1  is loaded on a preselected roll setting portion included in the copier body. FIG. 3 is a side elevation showing the paper roll  1  set on the paper roll setting portion. As shown, the roll setting portion includes a pair of supports  8  and a bottom plate  9  on which the supports  8  are positioned. Bosses  10  protrude downward from the bottom of each support  8 . A plurality of holes  11  are formed in the bottom plate  9  and capable of receiving the bosses  10 . The plurality of holes  11  allow the roll supporting portion to adapt to a plurality of standard roll sizes. The base  9  is formed of metal or similar conductive material for attracting magnets  12  (see FIG. 3) affixed to the bottoms of the supports  8 . In this configuration, when the bosses  10  are inserted into the holes  11 , the supports  8  are magnetically locked to the bottom plate  9 . 
     A pair of flange members  13  are inserted into opposite ends of the tubular core of the paper roll  1 . The flange members  13  each are made up of a flange portion  14  and a cylindrical support portion  15  smaller in diameter than the flange portion  14  and capable of being inserted into the core of the paper roll  1 . Three ribs  16  protrude from the outer circumference of one end of the support portion  15  remote from the flange portion  14  and are positioned at equally spaced locations along the circumference. Likewise, three ribs  3  protrude from the outer circumference of the other end of the support portion  15  and are positioned at equally spaced locations along the circumference. The ribs  3  in combination define an outside diameter substantially equal to the inside diameter of the core of the paper roll  1  and obviate a play (?) between the flange members  13  and the paper roll  1 . Further, three claws  17  alternate with the three ribs  16  on the end of the support portion  15  adjoining the flange portion  14 . The claws  17  press the inner wall of the core of the paper roll  1  to thereby lock the flange members  13  to the paper roll  1 , as will be described specifically later. 
     Each support  8  has two rollers  18  rotatably arranged side by side therein. The rollers  18  support associated one of the flange portions  14 , so that the paper roll  1  is freely rotatable. 
     FIG. 4 is an exploded view showing one of the flange members  13  in detail. As shown, the flange member  13  includes a flange body  19  made up of the previously stated flange portion  14  and cylindrical support portion  15 . The flange member  13  additionally includes a claw member  20 , a spring  21 , a presser  22 , and a lock/release lever  23 . The claw member  20  is received in the flange body  19  and protrudes from the outer circumference of the support portion  15 . The spring  21  constantly biases the claw member  20  and has one end seated on the presser  22 , so that the presser  22  compresses the spring  21 . The lock/release lever  23  is capable of being brought down by hand in order to cause the presser  2  to slide. Lugs or eccentric cams  27  protrude from part of the lock/release lever  23  adjoining the axis of rotation of the lever  23 . The claw member  20  has a spring seat  24  on which the other end of the spring  21  is seated, three radially extending arms  25 , and the previously mentioned three claws  17  at which the arms  25  terminate, as illustrated. The arms  25  are formed of resin or similar elastically deformable material. The lock/release lever  23  is engaged with bosses  26  formed on the inner circumference of the flange portion  14  and is angularly movable about the bosses  26 . When the lock/release lever  23  is brought down about the bosses  26 , the lugs  27  push the presser  22  into the flange body  19 . The lock/release lever  23  has a length sufficiently greater than the height of the lugs  27 , so that the operator can easily bring down the lever  23  in a locking direction. 
     More specifically, the flange body  19 , claw member  20 , spring  21 , presser  22  and lock/release lever  23  are sequentially arranged in the axial direction in this order, as shown in FIG.  4 . When the operator brings down the lock/release lever  23 , the lever  23  pushes the presser  22  into the flange body  19 . The presser  22 , in turn, compresses the spring  21  and thereby presses the claw member  20 . Consequently, the arms  25  of the claw member  20  are elastically deformed and force their claws  17  radially outward. 
     The movement of the flange member  13  will be described in detail with reference to FIGS. 5 and 6. FIGS. 5 and 6 respectively show the flange member  13  in a locked position and an unlocked or released position. As shown, the flange portion  19  has a tubular configuration whose one end is closed, and has three through holes formed in the end portion remote from the flange  14  and assigned to the three claws  17  of the claw member  20 . Such a configuration provides the flange portion  19  with mechanical strength and allows it to firmly support the paper roll  1 , which has substantial weight. Three pairs of triangular ribs  28  are formed on the inner wall of the above end of the flange body  19 . Each pair of ribs  28  are parallel to each other and assigned to a particular claw  17  for guiding it therebetween. In this sense, each pair of ribs  28  form, when the associated arm  25  deforms, guide surfaces in the flaring direction and the direction of height. Further, a tubular boss shaft  29  extends from the inner wall of the end of the flange body  19 . The boss shaft  29  guides the claw member  20  with its outer periphery and guides the presser  22  with its inner periphery. The spring seal  24  of the claw member  20  is formed with a hole corresponding to the boss shaft  29  and plays the role of a guide. 
     As shown in FIG. 5, to lock each flange member  13  to the paper roll  1 , the operator brings down the lock/release lever  23 . The lugs  27  of the lock/release lever  23  then push the presser  22  inward and thereby compress the spring  21 . The spring  21 , in turn, presses the spring seat  24 . As a result, the arms  25  elastically deform and cause their claws  17  to protrude radially outward via the holes of the flange body  19 , pressing the inner wall of the tubular core of the paper roll  1 . Because the claws  17  flare until they abut against and press the inner wall of the core, they surely lock the flange member  13  to the core without regard to the tolerance of the diameter of the core. The side of the presser  22  adjoining the flange  4  is formed with a bore complementary in shape to the outer contour of the presser  22 . The bore forms a catch  30  that the operator can use when fitting the flange member  13  into the paper roll  1 . Because the catch  30  is cylindrical and has no directionality, it is not dependent on the angular position of the flange member  13 . 
     As shown in FIG. 6, when the flange member  13  is unlocked from the paper roll  1 , the lock/release lever  23  is positioned right above the catch  30  due to the shape of the lugs  27 . This prevents the operator from touching the catch  30  and thereby prevents the operator from, e.g., forgetting to lock the flange member  13  to the paper roll  1 . As shown in FIG. 5, when the flange member  13  is locked to the paper roll  1 , the lock/release lever  23  pushes the presser  22  inward to a position where the presser  22  does not protrude from the flange  14 , making the end face of the flange member  13  flat. Such a flat end face allows the operator to surely see the locked position of the flange member  13  and easily handle the flange member  13 . It follows that the paper roll  1  with the flange members  13  can be stored in an upright position or in a sack, as desired. This makes it needless for the operator to fit and unfit the flange members  13  every time the operator replaces the paper roll  1 , contributing a great deal to easy handling. 
     FIGS. 7 and 8 are isometric views showing the flange member  13  in the locked position and unlocked position, respectively. As shown in FIG. 7, in the locked position, the lock/release lever  23  is brought down and makes the flange surface flat while exposing the catch  30  to the outside. As shown in FIG. 8, in the unlocked position, the lock/release lever  23  is raised and obstructs the operator&#39;s manipulation. 
     FIG. 9 shows a lock/release lever  23 ′ that is a modification of the above-described lock/release lever  23 . As shown, the lock/release lever  23 ′ is configured such that it can be brought down to either side about a fulcrum. The lever  23 ′ is symmetrical in the right-and-left direction, as viewed in FIG. 9, so that the operator does not have to care about the direction in which the lever  23 ′ should be brought down. The lever  23 ′ therefore further enhances easy operation, compared to the lever  23 . Moreover, while the lever  23  will be broken when forcibly brought down in the direction opposite to the expected direction, the lever  23 ′ is free from such an occurrence because it can be brought down in either direction. 
     In summary, it will be seen that the present invention provides a paper roll supporting device for an image forming apparatus having various unprecedented advantages, as enumerated below. 
     (1) The device is far easier to handle than the conventional screw type of device and free from an occurrence that flanges themselves rotate in the event of locking as in, e.g., Laid-Open Publication No. 7-48598 mentioned earlier. 
     (2) A large paper roll for use in, e.g., a copier is extremely heavy and must be supported by a great force. The device of the present invention transforms the rotation of a lever to a force that pushes pressing means inward, thereby reducing a load. The leverage (force reduction ratio) can be far greater than the conventional rotation type configuration. 
     (3) The device allows a paper roll to be stored in an upright position or in a sack when brought to a projection-free position. Narrow paper rolls can even be stacked one above the other. It is therefore needless for the operator to fit and unfit the device every time the paper roll is replaced. 
     (4) The operator does not have to care about the direction in which a lock/release lever should be brought down. The lock/release lever is therefore easier to operate than a lock/release lever that should be brought down only in one direction. Further, the lever, which can be brought down in either side, is free from damage ascribable to operator&#39;s forcible action. 
     (5) The device is easy to handle and promotes easy transport of a paper roll. Because the device uses a space that has customarily been a dead space, it is superior to a grip scheme as to space efficiency. 
     (6) The device prevents the operator from handling the device without fully locking the device to a paper roll. 
     Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.