Gtech Accutherm, Service Manual, Page: 19 / 132

Introduction
Service Manual for the Accutherm Ultra Printer 1-7
Mechanism
This section explains the Accutherm Ultra’s theory of operations.
Figure 1-1. Printer Block Diagram
Print Head
The print head in the Accutherm Ultra is a high speed, thick film device
configured as single row of 640 dots spaced at 8 dots/mm for a total printable
width of 80mm (3.15”). Print data is sent from the controller board as a serial data
stream at 8 MHz.The head elements are then activated by signals from the main
controller board to form the image on the paper. The Accutherm Ultra uses a two
level energy control system to compensate for dot history with all timing
controlled by the controller board electronics. The head also contains a thermistor,
which is used to monitor the temperature of the head substrate. Dot energy is
continually adjusted based on head temperature, supply voltage, dot history, and
paper sensitivity. The print head connects to the controller through a 28 position
Flexible Flat Cable (FFC).
Top Cover
Paper Feed
Motor
Du al S tep Mo tor
Driver
Al legro A 3988
(1000ma)
Step Motor Driver
Alleg ro A3 983
(400ma)
Knife Motor
Stack er Motor
MCF5353
Processo r
(BGA )
RA M
4Mb x 1 6
(BGA )
FLA SH
2Mb x 16
(BGA)
FPGA
(BGA )
Print
He ad
P ower Supply
a nd So ft S tart
Address/Data Bus
+
Clock
Oscillator
Cover
EEPROM
RS2 32
Driver
+24 VDC
from
internal
power
brick
+3.3V
+1.5V
P aper
Cut
Home
TOF JAM
On board
se nsors
(In terruptive)
Off board sensors
(reflective )
TOF Current
A djust
F
P
G
A
I
/
O
+
Pr int He ad
Buffer
Pr int He ad
Vo ltage Contro l
LED
Te st
Switch
Feed
Switch
O n Bo ard
Operator
Inte rface
LED LED
USB
Protectio n
Beepe r
USB
Clock
Debug Header
Program Header
No t
Pop ulat ed
+1.5V