Ink System Management; Ink System Operations - Epson Stylus COLOR 800 Service Manual

2.4 Ink System Management

This section explains how the ink system is controlled to protect the printheads and the ink supply system
to ensure high-quality output. This printer has several ink system control sequences which vary depending
on the combinations of the basic ink system operations. The printer selects the most suitable sequence by
referring to the various printer information such as values for the timers and counters stored in the
EEPROM, flag and numbers of sensor signals. This section describes the basic ink operations, timers
counters and ink sequences.

2.4.1 Ink System Operations

The basic ink system operations are as described below.
‰Rubbing
This operation is to rub the printhead surface against the felt part of the head cleaner (left half of the
blade) in the pump unit by shifting the CR from left to right. The printer operates this to eliminate ink
and dust adhered to the printhead surface to regain normal ink ejection state and ensure firm capping
operation. A little amount of ink is absorbed to the nozzle surface before Rubbing operation to let the
adhered objects come off easily.
‰Wiping
During this operation, the CR moves from right to left to rub the printheads against the rubber part of
the head cleaner (right half of the blade) in the pump unit. The printer performs this operation prior to
ink absorption by eliminating the ink and dust adhered on the printheads to regain normal ink ejection
state and ensure firm capping operation.
‰Ink Absorbing operation
This operation is to absorb ink from the ink cavities by rotating the pump for the both black and color
heads with the specified steps while the head surfaces are capped and the air valve is closed. The
printer performs this operation to eliminate the ink which has increased viscosity and bubbles around
the nozzles.
‰False Absorbing operation
This operation removes ink remaining inside the caps by rotating the black and color pumps with the
specified steps while the head surfaces are capped and the air valve is opened. This operation is
accomplished to remove ink from the nozzle plate by vacuuming and ejecting the ink remained after
the Ink absorbing operation and Flushing operations.
‰Micro Absorbing
This operation absorbs ink from the ink cavity by rotating the black and color pumps with the specified
steps while the head surfaces are capped and the air valve is opened. The purpose of this sensitive
operation is to eliminate bubbles formed in the ink cavities during the Ink absorbing operation.
‰Flushing operation
This operation is to eject the specified amount of ink from the head when the CR goes into the false
absorbing position. This is performed to avoid increase in ink viscosity. There are 3 types of Flushing
operations, as listed below;
Power flushing
Periodical flushing
Cleaning flushing
‰Micro Vibration
Micro Vibration is performed to prevent ink from increasing viscosity. It adds the micro vibration to the
ink inside the cavity by applying driver voltage and pulse which vibrate the piezo elements. The printer
only performs this operation while the CR motor is accelerating to move the CR for printing operation.
Rev. A
Table 2-12. Flushing Specification
Numbers of shots
4000 shots + 2V, Maximum 36V for the correct voltage of the
normal dot
36 shots Waveform for the normal dot
1400 shots Waveform for the normal dot
Operating Principles
Driver waveform
2-21