Apparatus and methods for sensing and clamping discs

Abstract

Apparatus and methods are provided. At least one clamping finger of a movable tray of a compact disc printer pushes against an outer periphery of a compact disc disposed on a surface of the tray to clamp the compact disc between the clamping finger and a pair of studs that protrude from the surface of the tray and engage a periphery of a hole passing through a center of the compact disc. A carriage of the printer for moving an ink jet cartridge attached thereto across the compact disc to deposit an image on the compact disc may include a sensor. The sensor can be used to determine the presence of a compact disc on the tray, whether the compact disc is clamped to the tray, and a dimension of the compact disc, and to perform a calibration method.

1 . A method of clamping a compact disc to a printer, comprising: 
 positioning the compact disc on a surface of a movable tray of the printer so that a pair of studs protruding from the surface of the tray extend into a hole passing through a center of the compact disc; and    moving at least one clamping finger into engagement with an outer periphery of the compact disc so as to push a periphery of the hole passing through the center of the compact disc against the pair of studs.    
   
   
       2 . The method of  claim 1 , wherein moving at least one clamping finger is in response to moving the tray into the printer.  
   
   
       3 . The method of  claim 1 , wherein moving at least one clamping finger further comprises: 
 moving the tray into the printer;    as the tray is moving, engaging a lug protruding from a stationary surface of the printer with an actuator arm connected to a first shaft rotatably attached to the tray as the tray moves past the lug, wherein the lug rotates the first shaft; and    imparting the rotation of the first shaft to a second shaft via a link movably connected between the first shaft and the second shaft, wherein the second shaft is rotatably attached to the tray and wherein the second shaft is connected to the at least one clamping finger so that the rotation of the second shaft rotates the at least one clamping finger.    
   
   
       4 . The method of  claim 1 , and further comprising biasing the at least one finger against the outer periphery of the compact disc during clamping.  
   
   
       5 . A method of clamping a compact disc to a printer, comprising: 
 positioning the compact disc on a surface of a movable tray of the printer so that a pair of studs protruding from the surface of the tray extend into a hole passing through a center of the compact disc;    moving at least one clamping finger into engagement with an outer periphery of the compact disc so as to push a periphery of the hole passing through the center of the compact disc against the pair of studs; and    verifying clamping of the compact disc.    
   
   
       6 . The method of  claim 5 , wherein verifying clamping of the compact disc comprises reflecting a beam of light off a surface of the at least one clamping finger.  
   
   
       7 . A method of operating a compact disc printer, comprising: 
 emitting a beam of light onto a predetermined point on a movable tray of the printer from a sensor disposed on a carriage of the printer;    indicating that the compact disc is clamped to the tray when a surface of a clamping finger coincides with the point and reflects the light back to the sensor, wherein when the clamping finger coincides with the point, the clamping finger is in engagement with an outer periphery of the compact disc; and    indicating a clamping error when the surface of a clamping finger does not coincide with the point and the light is not reflected back to the sensor, wherein when the clamping finger does not coincide with the point, the clamping finger is not in engagement with the outer periphery of the compact disc.    
   
   
       8 . The method of  claim 7 , and further comprising moving the tray and the carriage to align the sensor with the point.  
   
   
       9 . The method of  claim 7 , wherein when the surface of a clamping finger does not coincide with the point, the beam of light is emitted into a slot of the tray.  
   
   
       10 . A method of operating a compact disc printer, comprising: 
 aligning a sensor with a predetermined first point on a movable tray of the printer, wherein the predetermined first point is at a known first distance from a predetermined second point corresponding to a center of a compact disc when the compact disc is disposed on the tray and wherein the first and second points coincide with a slot in the tray that is substantially parallel to a direction of motion of the tray, the sensor disposed on a carriage of the printer for moving an ink jet cartridge attached thereto across the compact disc to deposit an image on the compact disc;    emitting a beam of light from the sensor into the slot at the first point;    moving the tray so that the beam of light moves within the slot toward the second point;    indicating that no compact disc is present when the beam of light arrives at the second point without being reflected;    when a compact disc is located on the tray, reflecting the beam of light back to the sensor from the compact disc when the beam of light encounters an outer periphery of the compact disc; and    computing a dimension of the compact disc by subtracting a distance traveled by the tray between the first point and the outer periphery of the compact disc from the first distance.    
   
   
       11 . The method of  claim 10 , and further comprising determining a type of the compact disc from a look-up table based on the dimension of the compact disc.  
   
   
       12 . The method of  claim 10 , and further comprising determining the distance traveled by the tray by counting a number of rotations of a stepper motor that moves the tray.  
   
   
       13 . A method of clamping a compact disc to a printer, comprising: 
 positioning the compact disc on a surface of a movable tray of the printer so that a pair of studs protruding from the surface of the tray extend into a hole passing through a center of the compact disc;    disposing an adaptor between an outer periphery of the compact disc and at least one clamping finger movably attached to the tray; and    moving the at least one clamping finger into engagement with the adaptor so as to push the adaptor into engagement with the periphery so as to push a periphery of the hole passing through the center of the compact disc against the pair of studs.    
   
   
       14 . The method of  claim 13 , and further comprising verifying clamping of the compact disc.  
   
   
       15 . The method of  claim 14 , wherein verifying clamping of the compact disc comprises reflecting a beam of light off a surface of the at least one clamping finger.  
   
   
       16 . The method of  claim 13 , wherein moving at least one clamping finger is in response to moving the tray into the printer.  
   
   
       17 . The method of  claim 13 , wherein moving at least one clamping finger further comprises: 
 moving the tray into the printer;    as the tray is moving, engaging a lug protruding from a stationary surface of the printer with an actuator arm connected to a first shaft rotatably attached to the tray as the tray moves past the lug, wherein the lug rotates the first shaft; and    imparting the rotation of the first shaft to a second shaft via a link movably connected between the first shaft and the second shaft, wherein the second shaft is rotatably attached to the tray and wherein the second shaft is connected to the at least one clamping finger so that the rotation of the second shaft rotates the at least one clamping finger.    
   
   
       18 . The method of  claim 13 , and further comprising biasing the at least one finger against the adaptor during clamping.