XPM 200HR™
Thermal Printer Family
HENGSTLER
®
Part No. D 690 074
Mod. No. 4 300113 LEV
page 14 of 32
Figure 8
3.5.2. Paper Guides
Figure 3 shows the two paper guides (one left and one right) at the rear of the print
mechanism. These should be adjusted to properly guide the paper into the printer.
Please note that it is important at all times for the paper path to be straight. Care
must be taken that the paper guides cause the paper to line up properly with the
paper roll holders or the fanfold source. A crooked paper path will increase the
likelihood of paper jams. The paper path should also be centered in the printer to
ensure the most reliable, jam-free operation.
To adjust the paper guides, simply slide them to the desired location.
3.5.3. Paper Entrance / Black Mark Sensor
There is a sensor in the paper entrance area of the print mechanism that serves
several functions. First, it detects paper entering the print mechanism and signals the
controller to activate the paper advance system. Similarly, when the printer is out of
paper, this sensor detects the fact and signals the printer accordingly.
The same sensor is also used to detect Black Marks. Black Marks are blackened
areas placed on the paper during the converting process. They are generally used, in
conjunction with appropriate printer commands, to advance the paper to a specific
position after each print job. One common reason for this is to so that preprinted
information is properly located with respect to information printed by the printer itself,
for example, printing a date inside a preprinted box. Black marks must be located on
the back (non-coated) side of the thermal paper.
The XPM 200HR™ printer is designed to allow for numerous Paper Entrance/Black
Mark sensor locations during manufacturing. (The location of this sensor cannot be
changed once the printer is built.) Also, two different sensor types can be used. The
most common is the reflex or reflective sensor, where the light source and detector
are located on a single chip. Basically, the light strikes the white paper surface and
reflects back into the sensor. If enough light reflects to activate the sensor, the printer
reports that paper is present. If there is not enough light reflected, the printer
assumes that this area is black, meaning the printer is on a black mark or the printer
is out of paper. There are 19 different possible positions for this sensor. The
possible positions of these sensors are detailed in Figure 13.
The XPM 200HR™ can also use a through-beam sensor. This type of sensor has a
separate light source and detector. The light is transmitted across the paper path into
a prism, which redirects it back across the paper path into the detector. When the
light is blocked and cannot reach the detector, the printer reports that paper is
present. When the light does reach the sensor, the printer concludes that there is no
paper present.
