Chapter Ii Theory Of Operation; Outline Of Mechanisms; Print Mechanism - Brother P-touch QL-700 Service Manual

CHAPTER II THEORY OF OPERATION

2.1 OUTLINE OF MECHANISMS

2.1.1

Print Mechanism

 Structure of Thermal Head
This machine adopts direct thermal printing system. The thermal head consists of 720
pieces of heating elements arrayed in vertical single row as shown in the Fig.2.1-1.
The dimension of each heating element is vertical length 0.0847 (0.0847mm pitch) x
horizontal width 0.13mm.
 Printing Process
A thermal tape is pressed against the thermal head in the printing process by the
force comes from a nip between the cylindrical rubber platen and the thermal head.
At this timing, voltage is applied selectively to 720 pieces of heating elements arrayed
on the thermal head. By this voltage application, the heating elements generate heat
and the thermal tape develops dots by itself at heat sensing points. After application of
voltage, the thermal tape is fed to the next printing position by the platen (0.0847mm).
This printing cycle is repeated and characters and geometries are printed on the tape.
One time travel distance (0.0847mm) is shorter than the width of a heating element
(0.13mm), so that continuous printing cycle can print characters and geometries on a
tape by developing dots with no gap.
Pitch 0.0847mm
Fig. 2.1-1 Heating Elements of Thermal Head
II - 1
0.13mm