Browse Prior Art Database

Constant Force Transfer Flap to Eliminate Voids On Side Two Of Electro-Photographic Printer/Copier Output

IP.com Disclosure Number: IPCOM000119234D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 142K

Publishing Venue

IBM

Related People

Bell, RG: AUTHOR [+5]

Abstract

A mechanical flap working essentially in the transfer area of a printer/copier to hold paper or other medium in intimate contact with the photoconductor reduces copy defects known as voids. These voids are caused by incomplete transfer of toner to the medium.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 49% of the total text.

Constant Force Transfer Flap to Eliminate Voids On Side Two Of Electro-Photographic
Printer/Copier Output

      A mechanical flap working essentially in the transfer
area of a printer/copier to hold paper or other medium in intimate
contact with the photoconductor reduces copy defects known as voids.
These voids are caused by incomplete transfer of toner to the medium.

      Disclosed is a flap system capable of at least two positions
for different sizes of medium, and a transfer flap system designed to
give nearly equal force on the medium in multiple positions.

      The transfer flap is used in an electrophotographic
printer/copier and holds the paper, or other output medium, against
the photoconductor during the transfer process to assure more
complete transfer of toner to the medium. Incomplete toner transfer
in local areas is known as voids. These voids are more pronounced on
side two of a two-sided copy due to the physical manipulation of
paper in transport, fusing and reregistration from the side one
processing.

      A typical transfer flap made for two paper sizes has two
sections, one offset from the other.  This offset allows the flap to
move to a first position for shorter paper (such as 11-inch), and to
a second position for longer paper (such as 14-inch).

      With stationary offset flaps, force of the flap in position 2
is increased over that of position 1 because of the incremental
motion of the flap mechanism from position 1 to position 2.  (See
Fig. 2 for typical force differences.) Problems which can result from
this higher force in position 2 are:
      1.   Toner can be left on the photoconductor because
           higher force makes cleaning the residual image
           more difficult.
      2.   Wear life of the flap is reduced with higher force
           causing more machine service.
      3.   Higher force enhances any static charge buildup on
           the back of the paper in the transfer zone and
           inhibits consistent transfer of corona.

      In the system disclosed, the three-to-four times force
differential between positions 1 and 2 is reduced to 1.1 to 1.3
times, thus resolving these problems.

      Fig. 1 consists of a shaft 1 driven on end F by a drive
source, such as a stepper motor (not shown), mounting bearings 2,
sleeve for position 2 flap 3, position 2 flap 4, sleeve for position
2 flap 6, seal/spacers 7, pin on position 2 flap sleeve 8, torsion
spring 9, pin on torsion spring drive collar 10, and torsion spring
drive collar 11.

      In operation, shaft 1 is held in place through brackets (not
shown) locating bearings 2.  Front bearing 2F has a shoulder to
locate the assembly left to right.  The bearings 2 are pressed onto
shaft 1.  Position 2 flap sleeve 3 is pressed onto shaft 1 and
rotates with the shaft.  Position 1 flap sleeve 5 pivots on shaft 1
on recessed bearings (n...