Printing Mechanism - Epson Stylus Color 400 Service Manual

EPSON Stylus Color 400 Service Manual
As major printer mechanisms in the figure 2-1, there are four major mechanisms as they are listed below.
1) Printing mechanism 2) Carriage unit 3) Paper pick up mechanism 4) Pump drive mechanism

2.1.1.1 Printing Mechanism

Basic principles of the print head which plays major role of printing mechanism is the same as previous
models; on demand type MACH head method, but there is some difference in the resolution. (Refer to
figure1-1) Also, unlike Stylus Color IIs, 820, 200 automatic correction type, in order to fix the dispersion of
mufti layer piezo electric element which is used for driving each nozzles, it is necessary to input the VH
value written on the side of print head by using exclusive program when you replace print head, control
board, or the printer mechanism.(However, there are no resistor array to decide the VH voltage on the
main control board.) Following explains print head.


PZT

PZT is an abbreviation of Piezo Electric Element. Print signal from C206 board is sent through the
driver board on the print head unit and to the PZT. Then, the PZT pushes the top cavity which has
ink stored, and make the ink discharge from each nozzle located on the nozzle plate.


Cavity Set

Ink which is absorbed from ink cartridge go through the filter and will be stored temporarily in this
tank, which is called "cavity" until PZT is driven.


Nozzle Plate

The board with nozzle holes on the printer head surface is called Nozzle Plate.


Filter

When the ink cartridge is installed, if any dirt or dust around the cartridge needles are
absorbed into the head inside, there is a great possibility of causing nozzle clog and
disturbance of ink flow and finally causing alignment failure and dot-missing. In order to
prevent this, filter is set at cartridge needle below and ink is once filtered here.
2-2
Figure 2-2. Print Head Sectional Drawing
Rev.A