Marks (Vertical Streaks) on Prints and Copies due to Scanning Problems

Marks on prints and copies are mostly due to dirt on the DF exposure glass [A], generally caused by adhesive contaminants (such as ball point pen ink and correction fluid).

Compared to non-adhesive contaminants (such as paper fragments and eraser dust), adhesive contaminants are more likely to lead to complaints from customers because of the following:

• Vertical streaks caused by adhesive contaminants are more visible in terms of image quality.
• Unless removed by cleaning, adhesive contaminants continue to produce vertical streaks, while non-adhesive contaminants stop producing streaks after they are dislodged.
• Many adhesive contaminants are difficult to remove by cleaning.

The ARDF DF3090 (D779) features a system (non-contact scanning) to reduce vertical streaks caused by adhesive contaminants.

Contact scanning: Other ADFs/ARDFs	Non-contact scanning: DF3090 (D779)
In contact scanning, the whole of the original comes into contact with the DF exposure glass [A] so that non-adhesive contaminants can be removed.	By means of the Mylar sheet [B], originals are kept slightly above the DF exposure glass [A], preventing adhesive contaminants from adhering to the glass.

The ARDF DF3090 (D779) can be converted from non-contact scanning to contact scanning for users who wish to reduce vertical streaks caused by non-adhesive contaminants.