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Print Emitter System with Variable Turnaround Margin

IP.com Disclosure Number: IPCOM000049274D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 3 page(s) / 61K

Publishing Venue

IBM

Related People

Cavill, BR: AUTHOR [+3]

Abstract

A linear print emitter system, as used in current printers, utilizes a three-track linear system with a print emitter track, a margin track and a turnaround emitter track. The print emitters occur every two or three print options depending on speed. The turnaround emitters are used to allow variable right margin turnaround. They are physically determined dark and light regions spaced along the carrier motion path. When stopping is desired, the carrier must move to a turnaround region and then turn. The stopping takes place within the turnaround emitter. While in this turnaround emitter, the microcontroller does not determine the direction of motion or measure the distance traveled as the turnaround emitter allows a "re-synchronization" of the print emitter counting.

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Print Emitter System with Variable Turnaround Margin

A linear print emitter system, as used in current printers, utilizes a three-track linear system with a print emitter track, a margin track and a turnaround emitter track. The print emitters occur every two or three print options depending on speed. The turnaround emitters are used to allow variable right margin turnaround. They are physically determined dark and light regions spaced along the carrier motion path. When stopping is desired, the carrier must move to a turnaround region and then turn. The stopping takes place within the turnaround emitter. While in this turnaround emitter, the microcontroller does not determine the direction of motion or measure the distance traveled as the turnaround emitter allows a "re-synchronization" of the print emitter counting. This turnaround region is required to allow the microcontroller time to move the forms.

Variable turnaround margins may be implemented with either a linear or a rotary emitter system. The linear system requires two print emitter tracks phased by 90 degrees, and some separate or attached margin generation capability.

The rotary system described here has the additional advantage that the emitters can be used to provide feedback speed information to the carrier drive control circuitry as well as generate the desired print emitter and turnaround signal.

The rotary system utilizes three emitters, as shown in the drawing. Two emitters (A and B) are designed to be symmetrical and in quadrature (phase shifted by 90 degrees) such that the emitter time values are used to generate the desired print emitter timings. The third emitter (C) is one half black end one half clear and is used by the left margin resynchronization logic in conjunction with an external switch to provide home or left margin information.

The output encoder A is divided by a shift register 11 to generate the symmetrical signal used by the microcontroller 12 as the print emitter. When turning around after printing to the right, the turnaround signal is initiated by setting an up/down counter 13 driven by the B emitter. Then the OR 14 of all the counter outputs will be active until the carrier again returns to the same place. When the counter is again at the set value, then the turnaround is complete end the turnaround signal is ignored until it is activated again. Direction information is developed by the direction detect logic 16 and determines the direction of the print emitter register shifting, and the count direction for the turnaround counter.

The print emitter that is sent to the microcontroller is the most significant bit out of the shift register. This register is loaded with a symmetrical bit pattern (3 on and 3 off) when the logical left margin region is exited, moving left into the print area. Changes in encoder A are used to clock the upward or downward cycling shift of the register. The direction is determined by the direction detect logic outpu...