Paper Separator Technology

Paper Separator Technology

Printers used in busy offices need to provide functions such as stapling and hole punching, in addition to printing. Aligning each sheet of paper is important for maintaining the quality of these operations. Alignment during high-speed printing on inkjet printers has been difficult until now, but Epson's original technology makes it possible.

Paper alignment mechanism

to the alignment handler of the finisher

Sheets of paper that have been printed by the printer are fed to the alignment handler of the finisher. In the alignment handler the sheet of paper is adjusted and bundled into a stack of paper. This is when problems can arise, such as paper misalignment (alignment failure) and adverse effects on the quality of processes like stapling. Let's take a look at how this mechanism is used to adjust paper as sheets are fed in at high speed.

The figures below show cross-section views of the alignment handler.

  • 1. Newly printed paper (unaligned paper) is fed by the feed roller into the alignment handler.
  • 2. As unaligned paper is fed in, the guide flap lowers and drops the unaligned paper onto the alignment surface.
  • 3. The paddles rotate and press the unaligned paper against the alignment surface to align it.
cross-section views of the alignment handler

Alignment problems caused by reduced slip

misalignment

Epson's inkjet method prints by ejecting ink onto a sheet of paper. This increases the amount of moisture on the surface of the paper, and makes it harder for sheets of paper to slide past one another, which presents a problem during alignment.
When unaligned paper is fed on top of sheets of paper that have already been printed and aligned, friction between the sheets of paper can cause the aligned paper to be pushed out, and the stack to become misaligned.

misalignment

If there is a lot of friction between the sheets of paper, when the paddles rotate to move unaligned paper against the alignment surface, they may be unable to pull the unaligned paper all the way back to the alignment surface, leading to misalignment.

Eliminating misalignment

To solve these misalignment problems, Epson has developed an original paper separator mechanism. This mechanism is made of polyethylene-terephthalate (PET) and is designed to restrain papers and reduce friction between sheets.

Let's take a look at the paper separator mechanism.

1Unaligned paper is fed into the alignment handler. At this point, the paper separators are pressing down on the aligned paper from above. Since they press down on the paper with a greater force than the frictional force between the sheets of paper, the unaligned sheet of paper cannot force aligned sheets of paper out of alignment.

2Also, because unaligned paper is fed in on top of the paper separators, the paper separators lie between the aligned and unaligned sheets of paper. The friction between the unaligned sheet of paper and the paper separators is lower than the friction between the sheets of paper. This reduction in friction ensures that the paddles can pull the unaligned sheet of paper against the alignment surface.

3Once the unaligned sheet of paper has been pulled back against the alignment board, another system component presses against both sides of the stack of paper. Then the paper separators rotate, retracting from between the unaligned and aligned sheets of paper.

4Upon completing one revolution, the paper separators return to their original position pressing down on the top sheet of aligned paper. The alignment handler is now ready for the next unaligned sheet of paper to be fed in.

misalignment

Using paper separators

The following two points allow paper separators to prevent misalignment.

1. The restraining force is greater than the frictional force.

Because the aligned sheets of paper are held in place by the paper separators, aligned sheets of paper are prevented from being pushed out of alignment by friction against the unaligned sheet of paper as it is fed in.

2. Frictional force is reduced.

Since the paper separators are between the aligned sheets of paper and unaligned sheet of paper, a space is created that reduces the contact area between the sheets. This reduces frictional force and prevents misalignment due to the unaligned sheet of paper not being pulled back against the alignment surface.

Epson's paper separator technology has made it possible to produce high-performance inkjet printers that deliver not only beautiful vivid, high-speed printing, but high-quality stapling and hole punching as well.

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