1. Field of the Invention
The invention relates to offset print ribbon such as, for example, high-speed magnetic ink character recognition (MICR) encoding ribbon. One particular offset print ribbon is provided in precut spools of about diameter 4.5 inches and width 2.5 inches, wound onto a low-cost plastic spool core and slit to width.
2. Background Art
For use in high-speed encoding printers, such as those used in certain document processing systems, offset print ribbon needs to be accurately located (to make sure that the ribbon stays straight and tracks correctly through a print mechanism), positively driven/retarded (to allow ribbon to be rapidly advanced between print cycles). By the nature of the ribbon (offset magnetic ink on a polypropylene substrate), the ribbon cannot be driven by any friction means acting on either ribbon web surface, either before or after printing. Further, the offset print ribbon needs to be quickly replaceable by operators with limited training and without tools, capable of being installed only in the one correct orientation, and of the lowest possible cost.
Existing approaches to using offset print ribbon in high-speed encoding printers have shortcomings.
For the foregoing reasons, there is a need for an improved ribbon spool assembly.
It is an object of the invention to provide an improved hand-separable ribbon spool assembly for use in a high-speed encoding printer.
In carrying out the invention, a hand-separable spool shaft assembly adapts a plain ribbon spool to provide drive and location functions. The hand-separable function is preferably provided by a push-and-turn function built into a two-piece shaft assembly which allows the shaft assembly to be separated into two parts, which are assembled to the plain ribbon spool, then locked together, all by hand action without tools.
The shaft locates the ribbon spool radially and in all three axes of translation, and provides the necessary bearing and locating surfaces to position the ribbon spool correctly in a printing mechanism. The shaft allows the ribbon spool to rotate to unwind/rewind correctly, and provides gear drive means to drive/retard the rotating ribbon spool.
In the preferred two-piece shaft assembly, spring means enclosed within one of the two shaft parts provides both the locking force for the push-and-turn function and the necessary lateral force to clamp the two shaft halves onto the ribbon spool to eliminate lateral tolerance variations.
Further, in the preferred two-piece shaft assembly, keying and locational features built into the other shaft part provide positive one-way-only assembly function. In this aspect of the invention, any attempt to assemble the ribbon spool in other than the correct orientation, or any incomplete assembly, will result in an assembly which cannot be completed and/or will not go into the printer mechanism for which it is designed.
As shown in
With continuing reference to
In accordance with the invention, system 10 may incorporate a printing mechanism including the improved ribbon spool lock assembly. For example, encoder 32 or encoder 36 could include a printing mechanism including the improved ribbon spool lock assembly.
In accordance with the invention, the printing mechanism may take a variety of forms.
Printing mechanism 50 is equipped with a pair of ribbon spools 56 and 58. Print mechanism 50 requires that the ribbon spools 56 and 58 be locked in position radially when print mechanism 50 is functioning. The locking function is provided by a positive radial spool lock which must be opened by some operator interaction when ribbon is to be replaced.
Printing mechanism 50 also includes a pivoting ribbon tension arm 70. Tension arm 70 applies tension to the ribbon for printing-related purposes. Tensioner arm 70 must be pivoted out of its normal operating position when ribbon is to be replaced, and held out of position during the replacement process, yet it must be returned to the normal operating position before normal printing recommences. Spring mechanism 72 biases tension arm 70.
A pair of locking plates 74 are built into the sides of printer mechanism 50. Locking plates 74 include locking features which protrude into printing mechanism 50 in such a way as to radially lock the ribbon spools in their correct position for printing.
Locking plates 74 are pivoting to a released position by means of an opposed pair of cam latches 76. Cam latches 76 are designed to be operated with the operator's fingers. When locking plates 74 are in the released positions, locking features 94, 96 are withdrawn from the ribbon spools, allowing them to be removed.
Locking plates 74 are further configured and shaped with additional features which are interlocked with the pivoting ribbon tensioner arm 70. This prevents locking plates 74 from being pivoted into the released positions until the ribbon tensioner arm 70 has been manually pressed into the correct position for ribbon loading. Only when the tensioner arm 70 is held in the correct position for ribbon loading can the locking plates 74 be placed in the released positions and the ribbon spools removed. Additionally, once locking plates 74 are placed in the released positions, other features on the locking plates engage the tensioner arm 70 and hold it in the ribbon loading position.
As best shown in
In a preferred embodiment, ribbon tensioner arm 70 is provided with a sensor which is actuated only when the arm is in the ribbon loading position. This sensor is connected to the control electronics for print mechanism 50 and, when actuated, tells the electronics that the printer is not ready.
Therefore, an operator cannot remove ribbon spools until locking plates 74 are placed in the correct, released positions. This cannot occur until tensioner arm 70 is placed in the loading position. Once tensioner arm 70 is in the correct position, locking plates 74 can be opened, at which point, tensioner arm 70 is held in the correct position and cannot be moved, and the printer reports a status of not ready. Ribbon spools 56 and 58 may now be removed and replaced, but the printer cannot function. Only when locking plates 74 are returned to the locked positions, securing the ribbon spools, will the tensioner arm 70 be released and allowed to return to the working position. At this point, ribbon spools 56 and 58 are locked in place, and the sensor on tensioner arm 70 reports that tensioner arm 70 is in the working position and the printer is ready.
The two shaft parts 114, 116 are assembled to the ribbon spool 112 and cooperate to provide a manual hand-action locking mechanism for locking the shaft parts 114, 116 together when assembled to the ribbon spool 112.
Driving shaft part 114 includes gear drive means 120, and bearing/locating surface 122. The hand-separable function is provided by a push-and-turn arrangement built into the two-piece shaft assembly 110. As shown, end 130 of cooperating shaft part 116 extends through aperture 124 of driving shaft part 114, and this cooperation provides the locking mechanism for locking the shaft parts together.
As best shown in
End 136 may be pushed against the bias of the enclosed spring to urge body 137 forward, causing stop 138 to move to position 140. In the same way, end 130 is moved to position 142.
The shaft assembly 110 locates ribbon spool 112 radially and in all three axes of translation and provides the necessary rotational bearing and locating surfaces to position the ribbon spool correctly in a printing mechanism. In a printing mechanism, the shaft allows the ribbon spool to rotate to unwind/rewind correctly, and provides gear drive means to drive/retard the rotating ribbon spool.
Keying and locational features 150 and 152 on shaft part 114 provide positive one-way-only assembly function. Any attempt to assemble the ribbon spool in other than the correct orientation, or any incomplete assembly, will result in an assembly which cannot be completed and/or will not go into the printer mechanism for which it is designed.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
Number | Name | Date | Kind |
---|---|---|---|
3432021 | Morelli | Mar 1969 | A |
4629136 | Vallance | Dec 1986 | A |
5238198 | Jingu et al. | Aug 1993 | A |
5352900 | Dragon et al. | Oct 1994 | A |
5599115 | Radcliffe et al. | Feb 1997 | A |