Browse Prior Art Database

Thermal Transfer Cut Sheet Printer Spot Color Post Processor

IP.com Disclosure Number: IPCOM000118031D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Skinner, DW: AUTHOR [+2]

Abstract

Printed cut sheet forms are fed into the post processing unit from a main print engine or a paper cassette with a picker mechanism. The leading edge of the paper is sensed by the first paper sensor, and then the trailing edge is sensed. From this, the paper length can be immediately determined since the paper is already at a constant velocity. The paper is driven to one side via tapered feed rolls and against a side edge. This locates the left side of the paper. The drive force of the feed rolls is such that the rolls will slip with respect to the paper in the lateral direction, due to the restraining force of the left-hand side edge.

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This is the abbreviated version, containing approximately 52% of the total text.

Thermal Transfer Cut Sheet Printer Spot Color Post Processor

      Printed cut sheet forms are fed into the post processing unit
from a main print engine or a paper cassette with a picker mechanism.
The leading edge of the paper is sensed by the first paper sensor,
and then the trailing edge is sensed.  From this, the paper length
can be immediately determined since the paper is already at a
constant velocity.  The paper is driven to one side via tapered feed
rolls and against a side edge.  This locates the left side of the
paper.  The drive force of the feed rolls is such that the rolls will
slip with respect to the paper in the lateral direction, due to the
restraining force of the left-hand side edge.

      The paper is driven into the print head area and the platen
roll is raised via a cam follower.  There is an initial clearance gap
between the print head and the platen roll such that paper easily
enters the print station.  As the paper enters the print station, the
platen roll "clamps" the paper against the print head as a result of
a cam action.  Changing the pivot location along the cam follower
will allow one to accommodate for different paper lengths.  When the
leading edge of the paper has passed through the print head area, the
cam allows the platen roller to come down onto the paper.  Pressure
is applied to the paper, ribbon, printhead through the platen roller
by a spring.  Prior to the platen roller engaging the paper, a knife
edge is placed just above the center line of the ribbon guide bar to
insure that the paper and ribbon separate after printing has taken
place.

      After the platen roll has contacted the paper, and the paper
continues forward, the leading edge of the paper will pass a "leading
edge sensor" and the logic in the printer will detect the top of the
sheet.  Printing now com...