1. In a printer assembly for printing a large number of characters on a medium from at least three replaceable character printing members, each character printing member containing a plurality of characters with at least some characters not contained on another printing member, the improvement comprising: a carriage means for operatively supporting a character printing member relative to the medium; storage means for holding a plurality of character printing members; exchange means for returning a character printing member from the carriage means to the storage means and replacing it on the carriage means with another character printing member; character memory storage means for receiving and storing a predetermined amount and location of characters that are contained on at least three separate printing members including means for designating all of the characters to be printed from each character printing member; control means for addressing the memory storage means and to select a first printing member and to scan the memory storage means to determine the character and location of all of the characters to be printed from the first printing member; means for moving the medium relative to the carriage means to provide a predetermined area of the medium for printing; means for moving the carriage means with an operative first character printing member across the predetermined area of the medium to coordinately and completely print all of the first group of designated characters from the first printing member; and means for sequentially activating the exchange means and control means to replace the first character printing member with a second character printing member for rescanning the previously printed predetermined area of the medium to interpolate the printing of all of a second group of designated characters from the second printing member and to further replace the second character printing member with a third character printing member to interpolate the printing of all of a third group of designated characters from the third printing member of the medium.
1. In a printer assembly for printing a large number of characters on a medium from at least three replaceable character printing members, each character printing member containing a plurality of characters with at least some characters not contained on another printing member, the improvement comprising: a carriage means for operatively supporting a character printing member relative to the medium; storage means for holding a plurality of character printing members; exchange means for returning a character printing member from the carriage means to the storage means and replacing it on the carriage means with another character printing member; character memory storage means for receiving and storing a predetermined amount and location of characters that are contained on at least three separate printing members including means for designating all of the characters to be printed from each character printing member; control means for addressing the memory storage means and to select a first printing member and to scan the memory storage means to determine the character and location of all of the characters to be printed from the first printing member; means for moving the medium relative to the carriage means to provide a predetermined area of the medium for printing; means for moving the carriage means with an operative first character printing member across the predetermined area of the medium to coordinately and completely print all of the first group of designated characters from the first printing member; and means for sequentially activating the exchange means and control means to replace the first character printing member with a second character printing member for rescanning the previously printed predetermined area of the medium to interpolate the printing of all of a second group of designated characters from the second printing member and to further replace the second character printing member with a third character printing member to interpolate the printing of all of a third group of designated characters from the third printing member of the medium. 2. The invention of claim 1 wherein the printing member is a print wheel.