XPM 200HR™
Thermal Printer Family
HENGSTLER
®
Part No. D 690 074
Mod. No. 4 300113 LEV
page 15 of 32
The through-beam sensor can also be used in a manner similar to a Black Mark
sensor. Instead of a Black Mark, a hole is used in the paper. The through-beam
sensor is located in one of 19 different possible locations. The positions of these
sensors are detailed in the Figure 14.
3.5.4. “Printhead Raised” Sensor
Two additional “Printhead Raised” microswitches are used to determine whether the
printhead is in the up (do not print) or down (ready to print position). (Please note
that these microswitches are wired in series, and so will only report “ready to print” if
both are closed.) Normally, most of the heat generated by thermal printing is
transferred to the paper being printed and is removed from the printer as the paper
advances. When the printhead is up, no heat is being transferred to the paper and
the heat remains in the individual dots, allowing them to overheat if activated
repeatedly. Because this may cause permanent damage to the printer, the
XPM 200HR™ firmware will prevent printing or paper loading if the head is up.
The output of this microswitch pair is also available via the Query function. See the
XPM 200HR™ Emulation Command Set Reference D 690 004 for details on
determining the printhead position and the printhead temperature.
3.5.5. Cutter Sensors
The XPM 200HR™ uses a “pizza-cutter” style paper cutter. A cutting disk moves
from one side to the other to sever the paper from the roll against a stationary blade.
Sensors are located at the end of travel for this cutter so the controller can detect
where the cutter blade is and determine in which direction it should be moved to cut
the paper. Printer throughput time is improved by cutting in both directions,
eliminating the need for the cutter to make a non-cutting movement to an arbitrary
“home” position.
3.5.6. Paper Exit Sensor
A sensor on the exit side of the print mechanism detects when paper has passed
through the cutter assembly and reached the paper exit.
3.5.7. Paper Pre-End (Paper Low) Sensors
The XPM 200HR™ has inputs for two pair of sensors indicating Paper Pre-End
(Paper Low). (Pairs of inputs are used to allow connection, in other applications, to a
dual-feed unit, which can handle two paper sources. In that case, one Paper Pre-End
input is used for each paper source.) One sensor pair is used to detect standard
Paper Pre-End (PPE). Connected to appropriately selected sensor, and positioned
the desired distance from the end of the paper supply, it will signal via a query
through the interface when paper has become low enough to activate this signal.
This is normally used to allow time to change an almost empty paper roll before it is
exhausted. This is an analog sensor input that is converted to a digital signal via
analog to digital (A/D) conversion. Therefore, it is possible to read their analog
values and use this information as a measure of sensor obstruction.
The second sensor pair is also for Paper Pre-End, but is intended for use as what is
commonly called a “weekend sensor” (PWE). While the standard PPE sensors
detect when paper has reached some user-defined point where a paper change will
be required shortly, PWE sensors are usually set to signal whether there is enough
paper remaining to make it through the weekend without replenishing the paper. This
is especially useful for installations where there is no staff available to change the
paper over the weekends. The PWE input is a direct digital input. Since no supply is
provided to power an LED-style sensor, these inputs are best used with a
microswitch.
