Service manual

Rev. 2.00
- 128 -
SRP-275
8. Appendix (Mechanism operating principles)
The printer mechanism of the SRP-275 consists of the following component mechanisms:
• Transport mechanism
• Printing mechanism
• Detection mechanism
• Auto cutter mechanism
• Easy paper loading mechanism
These components are described in detail in the following sections.
8-1 Transport mechanism
8-1-1 Head feeding system
This printer is using DC24V PM Type Stepping motor. As shown in figure, the motor section consists of the
motor, motor speed control IC, motor drive/brake circuit and motor speed interface.
When the HF(Head Feed) motor is driven and the HF motor pinion is moved in the direction of arrow B, the
rotational power is conveyed to the belt drive pulley, then the belt. Next the Carriage head ass’y, which is
fixed to the belt, moved in the direction of arrow B.
When the HF motor pinion is rotated in the direction of arrow A, the Carriage head ass’y is moved in the
direction of arrow A.
Belt-round
Pulley
Head
Carriage head ass’y
Ass’y-gear-pulley
Pinion-HF-motor
A B
A B
A
B
HEAD_PA
HEAD_An
HEAD_Bn
HEAD_B
HEAD_PBn
HEAD_PAn
HEAD_PB
HEAD_A
HEAD_HOLD
VCC_5V
VCC_24VVCC_24V
VCC_5V
VCC_5V
C6
1n 1608
R2
47K 1608
U1
SLA7024M
1
2
3 4
5
6
7
8
9 10
11
12
13
14 15
18
16
17
OUTA
Td_A
Vref_A GNDA
INA
INA
VCCA
OUTA
SENSEA SENSEB
OUTB
VCCB
Td_B
Vref_B GNDB
OUTB
INB
INB
C4
22p 1608
R11
1K 1608
C9
470p 1608
R10
100 1% 1608
R3
47K 1608
R7
1 1W 6432
R6
1 1W 6432
Q1
MMBT2222ALT1/ SOT23
C5
22p 1608
C7
1n 1608
R5
510 1% 1608
C1
100n 1608
C8
470p 1608
R8
680 1% 1608
R4
510 1% 1608
C2
100n 1608
R9
27 1% 1608