Printhead-carriage alignment and electrical interconnect lock-in mechanism

Abstract

A printhead cartridge and carriage assembly ( 10 ) is provided comprising: a carriage ( 12 ); a snap-spring ( 62 ) for securing a printing cartridge ( 14 ) in postion on the carriage; and an interconnect strip ( 16 ) for supplying electrical signals to the cartridge, including a force loading spring pad ( 24 ) for urging a portion of the interconnect strip against a portion of the cartridge. The cartridge has top ( 32 ), bottom ( 34 ), sides ( 36, 38 ), front ( 40 ) and rear ( 42 ) surfaces and includes a printhead ( 44 ) on the bottom surface, an electrical contact strip ( 46 ) on the back surface connected to the printhead, referencing pads ( 56 ) on the side surface, and a lip ( 64 ) on the back surface for accepting the snap-spring. Referencing surface ( 60 ) are provided for receiving the referencing pads on the cartridge. The spring pad urges the interconnect strip against the electrical contact of the cartridge. The printhead cartridge/carriage assembly of the invention requires only one hand of the operator to both insert and lock the cartridge in position. Further, the cartridge/carriage assembly provides simultaneous alignment of the printhead in the X, Y, and Z directions. Finally, contact between the printhead and the interconnect strip is reliably made each time the cartridge is inserted and locked in position, thereby ensuring proper nozzle firing each time.

What is claimed is:  
     
       1. A printhead carriage lock-in assembly ( 10 ) for use with a cartridge ( 14 ) in a printer, for printing on a print medium, comprising: 
       a. carriage means ( 12 );  
       b. said carriage means including base support means ( 18 ) for receiving the cartridge;  
       c. said base support means depending into referencing means ( 60 a,  60 b), for aligning the cartridge in proper printing position along at least two directions;  
       d. said base support means further including retention means ( 62 ) for causing the cartridge to be locked in position relative to said carriage means;  
       e. electrical interconnect means ( 16 ,  24 ,  46 ), for supplying control signals to the carriage;  
       f. the cartridge including a reference system ( 56 ) corresponding to, and generally coordinating with, said referencing system of said base support means, for providing proper alignment to the cartridge during its positioning relative to said carriage means, and for causing the cartridge to be retained in position during the printing operation;  
       g. said referencing means including a pair of downwardly depending, spaced-apart, generally oppositely disposed L-shaped members ( 60 a,  60 b), for engaging said reference system of the cartridge;  
       h. the cartridge including a rear ledge ( 64 ), and said retention means including spring means ( 62 ) for engaging said rear ledge in order to retain the cartridge in a locked position;  
       i. the cartridge further including a top portion ( 32 ), a bottom portion ( 34 ), and printhead means ( 44 ) generally secured to said bottom portion; and  
       j. said reference system ( 56 ) of the cartridge including two sets of similar pads ( 56 x,  56 y,  56 z), generally disposed near said bottom portion in a substantially symmetrical relationship relative to said printhead means;  
       k. said reference pads  pad ( 56 x) abutting one of said L-shaped members ( 60 a);  
       l. said reference pads ( 56 y) abutting the other  both L-shaped member  members ( 60 a,  60 b); and  
       m. the cartridge further including lock-out ear means ( 54 ), slightly protruding outwardly from said top portion ( 32 ), for enhancing the orientation of the cartridge inside said carriage means.  
     
     
       2. A printhead carriage lock-in assembly for receiving a cartridge having electrical contacts ( 46 ,  48 )  a contact strip (   46   ) , electrically conducting pads  (   48   ), a reference system ( 56 ) and a plurality of print elements, the print elements being disposed out of the plane of the electrical contacts  electrically conducting contact pads (   48   ), the printhead carriage lock-in assembly comprising: 
       a. carriage means;  
       b. said carriage means including base support means for receiving the cartridge;  
       c. said base support means depending into referencing means ( 60 a,  60 b), for aligning the cartridge into a proper printing position along at least two directions (x,y);  
       d. said referncing  referencing means generally coordinating with the reference system of the cartridge, for providing proper alignment to the cartridge during its positioning relative to said carriage means, and for causing the cartridge to be retained in position during the printing operation;  
       e. electrical interconnect means, for supplying control signals to the cartridge electrical contacts  electrically conducting contact pads of the cartridge; and  
       f. said electrical interconnect means being disposed out of the plane of the cartridge electrical contacts  print elements to avoid obstructing the firing path of the print elements onto a print medium, to minimize contamination of said electrical interconnect means resulting from the firing of the print elements, and to allow for a desirable relatively close spacing between the print elements and the print medium.  
     
     
       3. The assembly as defined in  claim 2 , wherein said referencing means includes a pair of downwardly depending, spaced-apart, generally oppositely disposed L-shaped members ( 60 a,  60 b), for engaging said reference system of the cartridge. 
     
     
       4. The assembly as defined in  claim 3 , further including retention means ( 62 ) for causing the cartridge to be locked in position relative to said carriage means; and 
       wherein the cartridge includes a rear ledge ( 64 ), and wherein said retention means includes spring means ( 62 ) for engaging said rear ledge in order to retain the cartridge in a locked position.  
     
     
       5. The assembly as defined in  claim 4 , wherein said carriage means further includes chute means ( 20 ), secured to said base support means ( 18 ), for helping guide the cartridge in position. 
     
     
       6. The assembly as defined in  claim 4 , wherein the cartridge further includes a top portion ( 32 ), a bottom portion ( 34 ), and printhead means ( 44 ) generally secured to said bottom portion; 
       wherein said reference system ( 56 ) of the cartridge includes two sets of similar pads ( 56 x, 56 y,  56 z), generally disposed near said bottom portion in a substantially symmetrical relationship relative to said printhead means;  
       wherein said reference pads  pad ( 56 x) abut  abuts one of said L-shaped members ( 60 a); and  
       wherein said reference pads ( 56 y) abut the other  both L-shaped member  members ( 60 a,  60 b).  
     
     
       7. The assembly as defined in  claim 5 , wherein said electrical interconnect means includes an interconnect strip ( 16 ), disposed intermediate said base support means and the cartridge, and terminating in a plurality of dimples ( 30 ) disposed in a predetermined arrangement, for effecting electrical contact with the cartridge. 
     
     
       8. The assembly as defined in  claim 7 , wherein the cartridge contacts include a contact strip ( 46 ) having a plurality of  electrically conducting pads ( 48 ) are disposed in a predetermined array on the contact strip (   46   ) for effecting electrical contact with said interconnect strip ( 16 ); 
       wherein said contact strip ( 46 ) provides a plurality of conducting paths to said resistors generally terminating in said conducting pads.  
     
     
       9. The assembly as defined in  claim 8 , further including spring pad means ( 24 ) disposed intermediate said base support means ( 18 ) and said interconnect strip ( 16 ), for forcing said interconnect strip against the cartridge, in order to maintain a good electrical interconnection therebetween. 
     
     
       10. The assembly as defined in  claim 9 , wherein said spring pad means includes a plurality of externally protruding bumps ( 26 ); and 
       wherein said bumps are disposed in a generally similar arrangement to that of said dimples ( 30 ) and said conducting pads ( 48 ) and in registration therewith, such that said bumps force said dimples against said conducting pads, in order to maintain a good electrical contact between said interconnect strip and the cartridge.  
     
     
       11. A printhead carriage lock-in assembly ( 10 ) for use with a cartridge ( 14 ) in a printer, for printing on a print medium, comprising: 
       a. carriage means ( 12 );  
       b. said carriage means including base support means ( 18 ) for receiving the cartridge;  
       c. said base support means depending into referencing means ( 60 a, 60 b), for aligning the cartridge in proper printing position along at least two directions;  
       d. said base support means further including retention means ( 62 ) for causing the cartridge to be locked in position relative to said carriage means;  
       e. electrical interconnect means ( 16 ,  24 ,  46 ), for supplying control signals to the carriage;  
       f. the cartridge including a reference system ( 56 ) corresponding to, and generally coordinating with, said referencing system of said base support means, for providing proper alignment to the cartridge during its positioning relative to said carriage means, and for causing the cartridge to be retained in position during the printing operation;  
       g. said referencing means including a pair of downwardly depending, spaced-apart, generally oppositely disposed L-shaped members ( 60 a,  60 b), for engaging said reference system of the cartridge;  
       h. the cartridge including a rear ledge ( 64 ), and said retention means including spring means ( 62 ) for engaging said rear ledge in order to retain the cartridge in a locked position;  
       i. said carriage means further including chute means ( 20 ) secured to said base support means ( 18 ), for helping guide the cartridge in position; and said chute means including spring means ( 58 ) for applying a relatively light force against the cartridge, to help guide its alignment and positioning inside said chute means.