Epson SEIJ98006 manual Printing Mechanism Block Diagram

EPSON Stylus Color 900 Revision C

2.2.2 Printing Mechanism

2. Receiving the signal, the Pre-driver outputs the head drive pulse

The printing mechanism of the printer is all included inside the

signal to the driver.

printhead. The printing method is EPSON-exclusive MACH system,

3. If no printing data is sent, pulse output from the driver is not applied

which is used in other EPSON ink jet printers, but the printhead is not

to the PZT in the printhead: because the transistor on the nozzle

compatible with any other printer. See Figure 2-2 for the printing

selector is not on.

mechanism block diagram.

4. If any printing data is sent from a PC, 5 serial data (3 for Y, M, and

C, and 2 for 2 rows of black) are sent to the nozzle selector from the

ASIC. Each serial data consists of 96 data since each row is

N o z z

le

+ 4 2

composed of 96 nozzles. When these data is all transferred, a Latch

S e le c

t o r

P u ls e

D r iv

e r

signal is output from the ASIC to the nozzle selector after specified

T e m p

e r

a

t u r e

period of time.

d e t e

c

t

io

n

c ir c u

it

t c h

L a

c ir

c u it

5. When the Latch signal is sent, a PZT signal is applied to the base

D is -

c h

a

e

side of the transistor via the latch circuit in the nozzle selector.

P T

P r e -

C h

a

A S I C

D r

iv e r

o r m c o m m a n d

P u ls e f

C a

6. Head drive pulse constantly output from the driver is then applied to

D a t a

the PZT by the pulse output after a set of serial data and the latch

L a t c h

signal are all transferred.

N o z z

le

T e m p e

r a t u r e d a t a

No z z le P la t e

7. The PZT drive pulse radiates large heat since it is driven with the

Figure 2-2. Printing Mechanism Block Diagram

basic drive frequency of 32.4 K Hz and also has such a large

amount of drive elements as 480 PZT. Therefore, the abnormal

temperature detection circuit is included in the nozzle selector to

The printing mechanism performs printing by applying voltage to the

detect temperature of each nozzle so that heat radiation stays under

PZT (integrated piezoelectric element) inside the printhead. With the

the maximum level. If the circuit detects abnormally high

voltage applied to the PZT, the cavity, a tank filled with ink, is pressed

temperature in any nozzle row, the printer regards the condition as

by the PZT and ejects ink from nozzles as the result. Unlikely to the

an accidental printing malfunction such as dot missing, and it

illustration, the actual number of the PZT included in the printhead in

automatically enters the cleaning CL2, the most powerful cleaning

this printer is 480, the same number as nozzles, and each PZT is

cycle. See the sensor descriptions in Chapter 2 for the operations

independently driven.

after this cleaning. The printhead also has the thermistor in it to

The steps below describes how the printing mechanism works.

subtly change the voltage level of the drive pulse in accordance with

the temperature condition in use.

1.Head drive pulse form command signal is output from the ASIC after the printer is turned on.

Operating Principles Printer Mechanism Operating Principles 48