Patent Publication Number: US-6714228-B1

Title: Ink ribbon cartridge with C-shaped 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 c-shaped sideplates which eliminate hinged connections and are easier to load 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 that must be manually manipulated to engage the covers in 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 ink ribbon and spools. Accordingly, it is desirable to develop a new and improved ink ribbon cartridge which meets the above-stated needs and others and provide 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 c-shaped sideplate used 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 a housing, an ink ribbon, first and second spools for holding the ribbon, and four spindles received within respective end openings in the spools. The housing has a first portion and a second portion which receive the first and second spools, respectively. The housing includes four openings which receive the spindles, particularly two c-shaped openings for each spindle. A pair of connecting members connect the first portion to the second portion. The first portion and second portions at least partially cover the spools. The first and second portions are spaced apart and generally parallel to each other and each have semi-cylindrical members. 
     The housing is formed of thermoplastic material and is of a one-piece construction. First and second portions each have wall members at opposite ends which are generally normal to a longitudinal axis of the portions and form the sideplates along with the connecting members. Each of the wall members is c-shaped and has an opening for receiving the spindles. The c-shaped walls selectively expand to receive the spindles. The first portion wall members are generally parallel to each other and second portion wall members are generally parallel to each other. 
     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 which does not have 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 c-shaped openings which allow 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 c-shaped 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 having a one-piece construction in accordance with the preferred embodiment of the present invention. 
     More particularly, the ink ribbon cartridge A has a housing comprising a first semi-cylindrical section  10 , a second semi-cylindrical section  12 , and connecting sections  14 ,  16  extending between and connecting 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 each spool. 
     semi-cylindrical section  10  has a first end  20  and a second end  22 . Each end  20 ,  22  has a wall or sideplate  24 ,  26 , respectively. Each sideplate  24 ,  26  is c-shaped and has an opening  28 ,  30 , respectively through a center of the sideplate for receiving a spindle extending from an end of a spool. Similarly, semi-cylindrical section  12  has a first end  31  and a second end  32  with sideplates or walls  34  and  36 . Sideplate  34 ,  36  are also c-shaped and have openings  38 ,  40 , respectively, formed in the center of the sideplates to receive spindles on the ends of the spools. Sideplates  24 ,  26  are spaced apart and generally parallel to each other and are approximately normal to a longitudinal axis of the semi-cylindrical section  10 . Similarly, sideplates  34 ,  36  are spaced apart and generally parallel to each other and are approximately normal to a longitudinal axis of the semi-cylindrical section  12 . The sideplates or walls are formed of a material that has some limited flexibility such that the openings can expand to receive the spindles therethrough and resiliently re-position to retain the spindle in position. Connecting section  14  interconnects sideplates  24 ,  34  and connecting section  16  likewise interconnects sideplates  26 ,  36  together. Connecting sections  14 ,  16  are spaced apart and generally parallel to each other. In FIG. 1, all of the c-shaped holes are shown to be approximately the same size; 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 c-shaped sideplates  24 ,  26 ,  34 ,  36  may be flexed or elastically deformed slightly to accommodate a spindle of a take-up spool. 
     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  has 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, disposed adjacent thereto. Spindle  72  further comprises a gear portion  82  adjacent the disk-shaped portion. Each spindle further comprises a flat disk portion  84 ,  86 , respectively, that has a diameter greater than the spool and sufficiently enlarged to retain the ink ribbon in wrapped relation thereto. 
     Spindle  70  is received by the opening  38  in sideplate  34  and spindle  72  is received in opening  40  of sideplate  36 . As the spindles contact outer edges of the sideplates, the openings deflect or elastically deform to receive the spindle. That is, the terminal edges of the sideplate have a slightly smaller access opening than the outer diameter of the spindles. The spindle disk-shaped portions engage in a position within the openings. Once the spindles are fully seated within the openings, the c-shaped sideplates return to their original configuration and retain the spindle in place. Disk-shaped portions  78 ,  80  extend through the openings  38 ,  40 , respectively. 
     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 axially inward from the disk-shaped portions. Spindle  92  further has a gear portion  110 . Disk-shaped portions  94 ,  96  are received by openings  28 ,  30 . The c-shaped walls or sideplates and openings are elastically deformed and expand outwardly slightly to receive the spindles. The spindles then snap into place within the openings and are retained in place due to the c-shaped configuration. An ink ribbon  120  is wound around the supply spool and take-up spool and is selectively transferred from one to the other as the gears rotate the spindles during use of the printer/facsimile machine. 
     FIG. 3 illustrates the spindles  92 ,  72  installed in openings  30 ,  40  of semi-cylindrical sections  10 ,  12 . FIG. 4 illustrates a bottom view of the ink ribbon cartridge showing the semi-cylindrical members  10 ,  12  covering at least a portion of spools  50 ,  60 . As seen in FIG. 2, the gear spindles  92 ,  72  are preferably identical. However, gear spindles of different diameter or shape may be used without departing from the scope and intent of the present invention. Similarly, spindles  70 ,  90  are shown to have the same diameter disk portions. However, these spindles may have varying diameters and shapes without departing from the scope of the present invention. 
     To install spools  50 ,  60  along with the ink ribbon into the ink ribbon housing, the spindles are snap fit into the openings within the sideplates  24 ,  26 ,  34 ,  36 . Once the spindle disk portions are received within the openings, the c-shaped openings of the sideplates return to their original configuration. Spindles are retained and locked into place within the openings of the sideplates. To remove the spools from the semi-cylindrical sections, the spindles and spools are then pulled away from the openings and again slightly expand the openings until a spindle can be removed from the openings. The spools are then removed from the ink ribbon housing. 
     The ink ribbon housing of the present invention thus eliminates the need for living hinges, or hinge members or snap arrangements which are conventionally 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 for easier manufacture and lower cost. 
     The ink ribbon housing also prevents improper mounting of the spindles and spools on the housing. The ink ribbon housing openings also provide better retention of the spools within the housing. Alternately, the ink ribbon housings may be configured to have identical holes 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.