Browse Prior Art Database

Auto Alignment Mechanism

IP.com Disclosure Number: IPCOM000118115D
Original Publication Date: 1996-Sep-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Hara, C: AUTHOR [+3]

Abstract

Disclosed is an auto alignment mechanism of a document printer. This mechanism can prevent slant printing more precisely than before.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 81% of the total text.

Auto Alignment Mechanism

      Disclosed is an auto alignment mechanism of a document
printer.  This mechanism can prevent slant printing more precisely
than before.

      In the past, a document printer which has a mechanism that
corrects the alignment of documents automatically detects the edge of
a document: (1) only by a pair of optical sensors (A,B) placed at the
back of the auto alignment rollers (2), and controls the orientation
of the document by the difference in timing detected by the sensors.

      This auto alignment mechanism has two kinds of problems.  One
is that the document may not go straight after it passes the sensors
(A,B) and may reach the print position (3) with an orientation
different from that at (2).  The other is when the top edge of the
document comes  with N degrees angle (for example, 45 degrees angle)
to the center line.  The sensors detect the edge of the document at
the same time.  This means that there is no difference between
detected timings;  then the document goes ahead without being
aligned.  In both cases, the  printer cannot prevent slant printing.
The Figure shows Auto Alignment  Mechanism.

      This invention makes use of another pair of optical sensors
(C,D) which are placed just before the print position.  They
ascertain whether or not the document got rotated after passing the
first pair of sensors (A,B).  When the document's top edge is not at
right angle to the center line of C and D, it is rej...