US 5,204,802 AGranted

Method and apparatus for driving and controlling an improved solenoid impact printer

AssigneeDataCard Corporation

InventorsRonald B. Howes, Jr., Thomas R. Emmons, Dennis J. Warwick

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Abstract

A method and apparatus for a two-pulse solenoid embossing system implementing an amplitude feedback circuit, i.e., current monitor (48), to provide precise amplitude and timing control over two current pulses (4, 5), and thereby provide precision control over the position and velocity of the embossing system's print elements (64a, 64b). To maintain the current amplitude during the second current pulse (5), the method and apparatus alternatively switches the power on and off to the solenoid coils (55) with a frequency such that a substantially constant current amplitude is maintained in the solenoid coils (55). The embossing system provides an improved solenoid body assembly (61) including a first stack of steel laminations (93), a center block (82) and a second stack of steel laminations (81). A plunger (62) is slidably connected to the solenoid body assembly (61) by shaft (63). Cavities (79) receive dowel pins (71) which are attached to plunger (62). The cavity and dowel pin arrangement (79, 71) prevents the plunger (62) from rotating.

An apparatus for controlling an impact imprinting system of a type including print elements used to imprint a chosen material, comprising:

a) solenoid means for driving the print elements in response to a current pulse;
b) current pulse generator means electrically interconnected to the solenoid means for generating and transmitting first and second current pulses to said solenoid means, said first current pulse having a contact duration and a contact amplitude sufficient to actuate said solenoid means to cause the print elements to move to a position proximate the chosen material, said second current pulse having an imprint duration and an imprint pulse amplitude sufficient to actuate said solenoid means to cause the print elements to imprint the chosen material to a desired character height;
c) current monitor means electrically interconnected to the current pulse generator means for sensing amplitude of said first and second current pulses and for transmitting first and second current amplitude sense signals representative of said amplitude of said first and second current pulses, respectively, and
d) current pulse control means electrically interconnected to said current pulse generator means and said current monitor means for switching said current pulse generator means between a pulse generating state and a nonpulse generating state, said current pulse control means including a first signal control means for comparing said first current amplitude sense signal received from said current monitor means to a first predetermined amplitude value corresponding to said contact pulse amplitude and, upon detection of said first predetermined amplitude value, switching said current pulse generator to said nonpulse generating state after a first predetermined period of time, corresponding to said contact pulse duration, said current pulse control means including a second signal control means for comparing said second current amplitude sense signal received from said current monitor means to a second predetermined amplitude value corresponding to said imprint pulse amplitude and, upon detection of the second amplitude value, switching said current pulse generator to said nonpulse generating state after a second predetermined period of time, corresponding to said imprint pulse duration.

1 more element

Facts

Application

07/749,625Filed 19 Aug 1991 · continuation

Priority

23 Nov 1988

Granted

20 Apr 1993

Term ends

Not estimatedThe source records don’t support an estimate.

Classification6 codes

B44B 5/0061
Machines or apparatus for embossing decorations or marks, e.g. embossing coins: characterised by the power drive
B41J 3/38
Typewriters or selective printing or marking mechanisms characterised by the purpose for which they are constructed: for embossing, e.g. for…
H01H 47/325
Energising current supplied by semiconductor device: by switching regulator
B44B
Machines, apparatus or tools for artistic work

Abstract

Claims16