Patent Publication Number: US-8523174-B2

Title: Media rotation and translation mechanism

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     Cross-reference is hereby made to commonly assigned and copending U.S. application Ser. No. 13/030,514, filed Feb. 18, 2011, and entitled “MEDIA ROTATION AND TRANSLATION APPARATUS” by Matthew Michael Roemer Storey, et al. The disclosure of the heretofore-mentioned application is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates broadly to a finisher transport module system, and more particularly, to an improved rotator and translator mechanism for use in controlling the orientation and alignment of sheets passing through a finisher transport module. 
     2. Description of Related Art 
     Finishing transport module systems for rotating and translating sheets passing through the system are known, for example, U.S. Pat. No. 6,811,152 which is incorporated herein by reference along with the references cited therein. Another example is shown in prior art  FIG. 1 , where a sheet rotator and translator mechanism for a finishing transport module  10  includes two rotator disc motors  30  and  32  that drive each rotator disc  12  and  14  independently. When turning in the same direction and at the same speed, the sheet will pass through the rotator device like any normal nip set (no rotation or directional offset). With the motors still rotating in the same direction and speed, steering idlers  16  and  18  can be rotated around the periphery of the discs to alter the inboard/outboard position of a sheet without rotation. This is useful for offsetting sheet sets in a stacker or for changing center and edge registration for finishing devices located downstream. To know when the sheet has been offset the desired amount, there is an edge sensor  40  that is positionable by a lead screw. The lead screw motor  33  positions the sensor  40  a set distance inboard/outboard for one sheet set, then repositions the sensor to detect the inboard/outboard position for the next sheet set. For sheet rotation, the motors controlling the rotator discs simply spin at different velocities. The larger the velocity differential, the faster the media is rotated. 
     A problem with this design is that the discs spin horizontally while the idlers spin vertically. Therefore, if the idler were to ride along a wide nip (like normal nip sets) there would be a relative motion issue. Prior art  FIG. 2  illustrates a top view of a wide disc nip design that includes a disc  45  that forms a nip with idler  46 . It can be seen that with R 1  being far smaller than R 2  there would be a significant relative motion problem. This would result in heavy marking, slip, unreliable rotation and translation, etc. To fix this, a very thin, high-pressure nip is used. The high pressure nip is shown in prior art  FIG. 1  and includes a very small contact point or ridge  13  between disc  12  and the idler  18  and  15  between disc  14  and idler  16 . This effectively removes the relative motion since there is essentially only one radius, but the pressure is very high. This high pressure is necessary to prevent slip, but ultimately does cause marking on certain media, especially coated sheets. 
     Thus, there is a need for a solution to the problem of the tendency of existing finishing transport module systems to mark certain types of coated media. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     Accordingly, in answer to the above-mentioned problem and disclosed herein is an improved rotator/translator mechanism that includes multiple thin discs that mate with an idler roll to distribute nip pressure and spin at different rotational velocities to produce the same linear velocity at the nip, thereby addressing and reducing the marking issue. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various of the above-mentioned and further features and advantages will be apparent to those skilled in the art from the specific apparatus and its operation or methods described in the example(s) below, and the claims. Thus, they will be better understood from this description of these specific embodiment(s), including the drawing figures (which are approximately to scale) wherein: 
         FIG. 1  is a partial frontal view of a prior art sheet rotator/translator mechanism for use in a finisher transport module; 
         FIG. 2  is a partial plan view of a prior art disc/idler roll nip configuration; 
         FIG. 3  is a partial perspective view of an improved sheet rotator/translator mechanism in accordance with the present disclosure; and 
         FIG. 4  is a partial frontal view of the improved sheet rotator/translator mechanism shown in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings wherein the showings are for the purpose of illustrating an exemplary embodiment and not intended as a limitation,  FIG. 3  illustrates a partial perspective view of an improved sheet rotator/translator mechanism in accordance with the present disclosure for accomplishing the sheet rotation and translation in a finisher transport module system. 
     A number of existing finishing transport module systems employ a media rotation and translation mechanism that utilizes two disc/idler pairs for re-registering conveyed sheets from center to side registration. However, the nip width between the disc and idler is thin relative to the diameter of the disk to avoid slippage, and the resulting high nip pressure has caused marking on coated media. In accordance with the present disclosure, the one thin disc has been replaced with multiple concentric thin discs that distribute nip pressure and spin at different rotational velocities to produce the same linear velocity at the nip and thereby reduce marking of coated media. As shown in  FIGS. 3 and 4 , a sheet rotator/translator mechanism  100  includes at least two discs that form a nip with an idler. They each have a small ridge or contact point thereon between the discs and idler, but as the number of contact points increase, the pressure at each is reduced. It is feasible that more than two discs could be used, if desired. For each disc added, a different radius of contact will be introduced. Therefore, the discs cannot spin at the same velocity or there will once again be a differential velocity issue for the linear motion of the media. To prevent adding more motors, the extra disc(s) are geared off the same drive motor to compensate for the varied radii. 
     That is, inner discs  105  and  101  supported in platform  110  are mounted to motor shafts  121  and  126  and drivingly connected to motors  120  and  125 , respectively. Gear  130  is mounted directly to motor shaft  121  while gear  131  is mounted directly to motor shaft  126 . Outer discs  106  and  102  are mounted to bearings and therefore spin freely about respective motor shafts  121  and  126 . Outer discs  106  and  102  are also attached to the gears  132  and  133 , respectively. Finally, external shafts  138  and  139  are attached to gears ( 134 ,  136 ) and ( 135 ,  137 ), respectively. As shown in  FIG. 4 , gears  130  and  131  through belts  140 ,  142 ,  144  and  146  drive external shafts  138  and  139  which in turn drives the gears ( 134 ,  136 ) and ( 135 ,  137 ) and outer discs  106  and  102 . External shafts  138  and  139  allow for the necessary speed adjustments to take place, such that, each inner and outer disc set rotate at different velocities with matched linear velocities. Thus, when paper is fed through the nip, there will be no relative motion issues regardless of the motor velocity or the nip position yet the pressure at each contact point is reduced and marking is eliminated. 
     It should now be understood that an improved rotator/translator mechanism has been disclosed for use in a finishing transport module system that includes multiple thin discs which mate with an idler roll to distribute nip pressure and spin at different rotational velocities to produce the same linear velocity at the nip and thereby prevent marking of coated paper. 
     The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others. Unless specifically recited in a claim, steps or components of claims should not be implied or imported from the specification or any other claims as to any particular order, number, position, size, shape, angle, color, or material.