Digital printer

A digital printer for printing in alpha-numeric character form digital information received from a recirculating-type buffer memory device in the form of a video-type signal refreshed at a predetermined rate, which comprises:

• a plurality of spindles mounted in tandem on a common rotatable shaft, each of said spindles having a spiral electrical conductor at its periphery extending 360.degree. around said spindle, said electrical conductors being electrically isolated from each other, and wherein the spiral conductors on adjacent spindles are displaced about the axis of said spindles and the spiral conductors on abutting spindles are terminated in the same exact transverse plane;
• a synchronous electric motor for rotatably driving said spindles at a substantially constant speed;
• a rotatably mounted paper drive roller for moving a continuous sheet of paper past said rotatable spindles in a direction normal to the axis of said spindles;
• speed reducing means for rotatably driving said paper drive roller from said synchronous electrical motor in the same direction of rotation as said spindles and at a speed of rotation proportional to, but substantially less than the speed of rotation of said spindles so that the paper and the segments of said spiral electrical conductors in juxtaposition thereto are moving in the same direction, with the velocity of the paper being substantially less than the tangential velocity of the spiral conductors;
• printing means for forming a mark on said paper responsive to an electrical signal applied to said spiral electrical conductors;
• printer control means for receiving a video-type electronic signal representative of alpha-numeric characters corresponding to said digital information and simultaneously producing a plurality of electrical output signals corresponding in number to the number of said spindles, each of said electrical output signals being in phase sequence with the rotation of the respective spindle;
• and
• electrical conductor means for separately conducting the output signals from said printer control means to the corresponding spiral electrical conductor;
• whereby a matrix of marks is placed on the paper so as to form alpha-numeric characters corresponding to said digital information.

A digital printer for printing in alpha-numeric character form digital information received from a recirculating-type buffer memory device in the form of a video-type signal refreshed at a predetermined rate, which comprises:

• a plurality of spindles mounted in tandem on a common rotatable shift, each of said spindles having a spiral electrical conductor at its periphery extending 360.degree. around said spindle, said electrical conductors being electrically isolated from each other, the spiral conductors on adjacent spindles being displaced 180.degree., and wherein the spiral conductors on abutting spindles are terminated in the same exact transverse plane;
• a synchronous electric motor for rotatably driving said spindles at a substantially constant speed;
• a rotatably mounted paper drive roller for moving a continuous sheet of paper past said rotatable spindles in a direction normal to the axis of said spindles;
• a speed reducing gear train for rotatably driving said paper drive roller from said synchronous electrical motor in the same direction of rotation as said spindles and at a speed of rotation proportional to, but substantially less than the speed of rotation of said spindles so that the paper and the segments of said spiral electrical conductors in juxtaposition thereto are moving in the same direction, with the velocity of the paper being substantially less than the tangential velocity of the spiral conductors;
• printing means for forming a mark on said paper responsive to an electrical signal applied to said spiral electrical conductors;
• printer control means for receiving a video-type electronic signal representative of alpha-numeric characters corresponding to said digital information and simultaneously producing a plurality of electrical output signals corresponding in number to the number of said spindles, each of said electrical output signals being in phase sequence with the rotation of the respective spindle, said means including (1) first and second shift registers, each of said shift registers being capable of storing information corresponding to one complete print line of marks, (2) means for loading said video-type signal corresponding to one complete line of marks into one of said registers and loading said video-type signal corresponding to the next print line of marks into the other of said shift registers, the video-type signal being alternately shifted between said shift registers, (3) means for alternately unloading the information stored in said shift registers to the spiral electrical conductors, the inactive shift register being unloaded during the period that the other of said shift registers is being loaded, one of said shift registers being loaded and the other of said shift registers being unloaded during each refresh cycle of said recirculatingtype buffer memory device, and (4) means to determine the end of each page of information and provide a space between adjacent pages, said printer control means and said synchronous motor being supplied with power from a common source;
• whereby a matrix of marks is placed on the paper so as to form alpha-numeric characters corresponding to said digital information.