Patent Publication Number: US-6659664-B1

Title: Ink ribbon cartridge with expandable sideplates

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to an ink ribbon cartridge for use with a printer or facsimile machine and, more particularly, to a thermal ink ribbon cartridge having one piece expandable sideplates which eliminate hinged connections and are easier to load with ink ribbon. The invention provides for an ink ribbon cartridge which ensures proper, reliable mounting of an ink ribbon. 
     Generally an ink ribbon cartridge is used because of the simplicity of handling when a thermal printer is used to print on paper. However, when a thermal printer uses a large ink ribbon cartridge, it is uneconomical for the whole cartridge to be thrown away after use. To obviate this drawback, an ink ribbon alone is replaced. The ink ribbon typically includes a band-like sheath comprising a resin film with a layer of ink formed on one side and is wound around a pair of cardboard spools. 
     A prior art ink ribbon cartridge using this type of ink ribbon is constructed such that at the time of ink ribbon replacement, a cover is unhinged, the used ink ribbon is taken out, and four spindles are removed from notches in the cartridge housing and from ends of the spools. The housing includes covers over each of the spools which are attached to the frame of the housing by living hinges and are secured into place by snaps which engage the covers and the frames of the housing. The covers are formed of two semi-cylindrical portions. The covers are locked into place by the snaps after the spools have been installed into the housing. Subsequently, the ink ribbon cartridge is mounted into a printer or facsimile system. 
     It is desired to provide an ink ribbon cartridge which does not have hinge members or snap members and is easy to load and unload with replacement ink ribbon and spools. Accordingly, it is desirable to develop a new and improved ink ribbon cartridge which meets the above-state needs and others and provides better, more advantageous overall results. 
     SUMMARY OF THE INVENTION 
     Generally speaking, the present invention relates to an ink ribbon cartridge which has a one-piece sideplate for installing and removing ink ribbon and spools. 
     More particularly, the invention relates to an ink ribbon cartridge which has a one piece sideplate which is expandable to easily remove and install take-up and supply spools having ink ribbon attached thereto. Thus, there are no hinge members or lock snap features required to retain the spools and ink ribbon within the ink ribbon cartridge. 
     In particular, an ink cartridge includes an ink ribbon, first and second spools for holding the ribbon, and four spindles. A spindle is received within a respective opening in an end of the spools. The housing has a first portion and a second portion which receive the first and second spools. A pair of sideplates connect the first portion to the second portion. The sideplates expand to allow the spindles to be installed within aligned holes of the sideplates. The sideplates are spaced apart and are generally parallel to each other. The first portion and second portion each have semi-cylindrical members that at least partially cover the spools. 
     The housing is formed of thermoplastic material and is a one-piece construction. First and second portions of the housing each have wall members at opposite ends which are generally normal to a longitudinal axis of the portions. Each of the wall members has a hole or opening for receiving the spindles. The sideplates are selectively pulled in opposing directions from a first dimension between the sideplates to a second dimension which is slightly greater than the first dimension. 
     One advantage of the present invention is the provision of an ink ribbon cartridge having a one piece construction to minimize parts that is easy to manufacture. 
     Another advantage of the present invention is the provision of an ink ribbon cartridge that eliminates any hinge members or snap lock features and is easy to load and unload with ink ribbon and spools. 
     Yet another advantage of the present invention is the provision of an ink ribbon cartridge which provides better retention of take-up spools and supply spools within the ink cartridge housing. 
     Still other aspects and advantages of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may take form in certain components and structures, a preferred embodiment of which will be illustrated in the accompanying drawings wherein: 
     FIG. 1 is a perspective view of a one piece ink ribbon cartridge housing having expandable sideplates in accordance with the preferred embodiment of the present invention; 
     FIG. 2 is a top plan view of the ink ribbon cartridge of FIG. 1 with supply and take-up spools mounted therein; 
     FIG. 3 is a side elevational view of the ink ribbon cartridge of FIG. 1 with supply and take-up spools installed therein; and, 
     FIG. 4 is a bottom plan view of an ink ribbon cartridge of FIG. 1 having supply and take-up spools and an ink ribbon mounted therein. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, wherein the showings are for purposes of illustrating the preferred embodiment of the invention only and not for purposes of limiting same, FIG. 1 shows an ink ribbon cartridge IRC having a one piece construction in accordance with the present invention. 
     More particularly, the ink ribbon cartridge has a first semi-cylindrical portion or section  10 , a second semi-cylindrical portion or section  12 , and connecting sections or sideplates  14 ,  16  extending between and interconnecting the first and second semi-cylindrical sections. The ink ribbon cartridge housing is preferably unitarily molded of a resin or similar material. Each semi-cylindrical section  10 ,  12  extends along the length of either a supply spool or a take-up spool and partially covers a periphery or circumference of each spool. 
     Semi-cylindrical section  10  has a first end  20  and a second end  22 . Each end  20 ,  22  has a wall  24 ,  26 , respectively, spaced in generally parallel relation with each other and normal to an elongated axis separating them. Each wall  24 ,  26  is preferably circular or round in shape and has an opening or a round hole  28 ,  29 , respectively through a center of the wall. Similarly, semi-cylindrical section  12  has a first end  30  and a second end  32  with axially spaced walls  34  and  36 . Walls  34 ,  36  are likewise preferably circular or round in shape and have openings or round holes  38 ,  40 , respectively, formed in the center of the walls. Similarly, walls  34 ,  36  are generally parallel to each other and are approximately normal to a longitudinal axis of the semi-cylindrical section  12 . 
     Sideplate  14  connects walls  24 ,  34  together and sideplate  16  connects walls  26 ,  36  together. Sideplate  14 ,  16  are spaced apart and generally parallel to each other. The sideplates have a configuration that conforms to the printer or facsimile machine, and maintain the connecting sections in generally fixed, spaced relation. 
     Openings  28 ,  29  preferably are equal in diameter; similarly, openings  38 ,  40  are equal in diameter. In FIG. 1, all of the opening formed in the walls are shown to have approximately the same diameter; however, the openings may be of varying diameters without departing from the scope of the invention. 
     The ink ribbon cartridge is formed of a resilient material such that the sideplates  14 ,  16  may be grasped by the user and pulled outwardly in opposing directions A, B thus expanding the length of semi-cylindrical sections  10 ,  12  and slightly pulling apart walls  34 ,  36  and walls  24 ,  26  from a first dimension between the walls to a second dimension slightly greater than the first dimension for receiving spools between the walls. The pulling force imposed on the sideplates remains in the elastic level so that the sideplates return to their original spacing upon release of the pulling force. 
     Referring now to FIG. 2, a take-up spool  50  is received within semi-cylindrical section  12  and a supply spool  60  is received within semi-cylindrical section  10 . Preferably, spools  50 ,  60  are made of cardboard, however, other materials may be used without departing from the scope of the present invention. Take-up spool  50  receives a spindle  70  at one end and a spindle  72  at an opposite end. The spindles are preferably made of a resin or thermoplastic material. As seen in FIG. 2, each spindle has a cylindrical section  74 ,  76 , respectively and a disk-shaped portion  78 ,  80 , respectively, adjacent thereto. Spindle  72  further comprises a gear portion  82  that cooperates with a drive gear (not shown) provided on the printer or facsimile machine in a manner well known in the art. Each spindle further comprises an enlarged diameter flat disk portion  84 ,  86 , respectively, that is dimensioned to prevent passage through the wall openings  28 ,  29  or  38 ,  40 . 
     Spindle  70  is received by opening  38  in wall  34  and spindle  72  is received in opening  40  of wall  36 . Particularly, disk-shaped portions  78 ,  80  are dimensioned to extend through the openings  38 ,  40 , respectively, and can be freely rotated relative to the housing. 
     Spool  60  has spindles  90 ,  92  at opposite ends thereof. As with the other spindles, spindles  90 ,  92  have disk-shaped portions  94 ,  96 , and cylindrical portions  98 ,  100 , respectively. Each spindle also has a flat disk portion  102 ,  104 , respectively, disposed adjacent the cylindrical portions. Spindle  92  further has a gear-portion  110  that matingly engages a gear (not shown) operatively associated with the printer or facsimile machine. Disk-shaped portions  94 ,  96  are received in openings  28 ,  29  of walls  24 ,  26 , respectively. An ink ribbon  120  is wound around the supply spool and take-up spool. In FIG. 2, the ink ribbon is wound around the spools so that the spools rotate in opposite directions as the ink ribbon is advanced from the supply spool to the take-up spool. It will be appreciated, however, that the ink ribbon can be wound so that the spools rotate in the same direction without departing from the scope and intent of the present invention. 
     FIG. 3 illustrates the spindles  92 ,  72  installed in openings  29 ,  40  of semi-cylindrical sections  10 ,  12 . FIG. 4, on the other hand, illustrates a bottom view of the ink ribbon cartridge showing the semi-cylindrical members  10 ,  12  covering at least a portion of the circumference of the spools  50 ,  60 , here extending over approximately 180° and along the entire axial length. As seen in FIG. 2, the gear spindles  92 ,  72  are preferably identical. However, different gear spindles of varying diameter or shape may be used without departing from the scope of the present invention. Similarly, spindles  70 ,  90  are shown to have the same diameter disk portions. These spindles, though, may have varying diameters and shapes to meet the particular needs or requirements of the printer or facsimile machine. 
     To install spools  50 ,  60  along with the ink ribbon into the ink ribbon housing according to a preferred method of the present invention, the sideplates  14 ,  16  are pulled apart in opposing directions A and B as illustrated in FIG.  1 . Thus, walls  24 ,  26  are slightly pulled apart from each other and walls  34 ,  36  are slightly pulled apart from each other to provide for a slightly greater dimension between the walls for receiving the spindles  50 ,  60 . The spindles are then snap fit into the openings within the walls  24 ,  26 ,  34 ,  36 . Once the spindle disk portions are received within the openings, the pull-apart force is released from the sideplates  14 ,  16  and the housing is allowed to return to its original configuration. The spindles are then retained and locked into place within the openings of the walls of the semi-cylindrical sections. To remove the spools from the semi-cylindrical sections, again, the sideplates  14 ,  16  are pulled apart until the spools are able to be released from the openings retaining the spindles. The spindles and spools are then pulled away from the openings and are removed from the ink ribbon housing. Then the force applied to the sideplates  14 ,  16  is released, thus allowing the ink ribbon housing to again return to its original configuration. 
     The ink ribbon housing of the present invention thus eliminates the need for living hinges or hinge member or snap arrangements which have heretofore been used to retain the spindles and spools onto the ink ribbon housing. The ink ribbon housing may be compatible with a variety of dimensions of spindles and spools. The housing allows for easy removal and installation of spools and spindles and eliminates extra components allowing for easier manufacture at a reduced cost. 
     The ink ribbon housing also prevents improper mounting of spindles and spools on the housing. Alternately, the ink ribbon housing may be configured to have identical openings in each location to allow for spindles to be interchanged at different locations on either semi-cylindrical section  10  or  12 . 
     The invention has been described with reference to a preferred embodiment. Obviously, alterations and modifications will occur to others upon a reading and understanding of this specification. It should be noted that variations on the configuration of the ink ribbon housing would fall within the scope and intent of the present invention. The specification is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.