Print Head Control Circuit - Epson Stylus Color 400 Service Manual

2.2.2.6 Print Head Control Circuit

The print head control circuit of Stylus Color 400 has following characteristics.

Common wave form circuit became one HIC.

Slight vibration mode is added.(when the CR motor is accelerating)

High speed drive 14.4Khz (trapezoidal wave form

Big Nozzle configuration (resolution in the vertical direction)90dpi
(However, black nozzle is 2 lines structure)
Also, Stylus Color 400 does not have Micro-dot control as dot shooting control, but there are two types;
Normal-dot and Normal dot-2dot. Normal-dot-2dot was called Dual Firing in the Stylus Color IIs/820.
These setting/change are controlled automatically by setting of the printer driver that is determined
by the user. The followings are required conditions to perform the normal-dot 2-dot.

At the OHP sheet setting (360X360 dpi)

At the ordinary paper and resolution 360X360 dpi setting
The control circuit is considered as 2 divided parts; 1) trapezoidal wave form generation circuit
(common drive circuit) to drive PZT in the head, and 2) Nozzle-selector drive circuit to determine
which nozzle should be used. The Nozzle-Selector is attached to the head unit just like the previous
models. The common drive circuit is sumed as one HIC and mounted on the C206 main board.
Figure 2-24. Print Head Control Circuit Block Diagram
[Common drive circuit]
The shape of trapezoidal wave form will be different according to the printing operation, slight vibrations at
the non-printing nozzle and waiting condition. However, IC6(H8D2813) generates all wave forms as drive
wave forms by resistance(electric) welding control of common voltage drive control signal that is output
from the IC2(E05B44) in the figure above.
Item
Drive Power Voltage
Final drive element
Operation at the Reset
This common voltage trapezoidal wave form can be observed anytime after the +5V rises even if there is
printing data or not. (Q7:3-pin,Q9:3-pin and GND on the C206 main board)
Rev.A
Table 2-13. Specifications of H8D2813 Operation
42 5 %
Starts supplying after 5V rises and be stabilized./ Stops
supplying before +5V drops.
2SC3746(for charging), 2SA1469(for discharging)
Off on the both charging and discharging sides.
Supplies drive power source.
Chapter2 Operating Principles
Contents
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