Brother MFC 5490CN - Color Inkjet - All-in-One, Service Manual

Page: 45 / 439

3-8 Confidential
3.2.2 Printing Mechanism
The printing mechanism consists of the following.
„
Ink supply and ink jet mechanism ( Section 3.2.2.1 )
„
Head maintenance mechanism ( Section 3.2.2.2 )
„
Carriage drive mechanism ( Section 3.2.2.3 )
„
Paper pulling-in, registration, feeding and ejecting mechanisms ( Section 3.2.2.4 )
The ink supply mechanism supplies ink to the head/carriage unit, in which the ink jet
mechanism sprays ink droplets from the head nozzles onto paper.
The major components of the ink supply mechanism (shown on page 3-10 ) are:
- Ink refill assembly: This secures the ink cartridges and connects them to the corresponding
ink supply tubes.
- Ink supply tubes: These supply the head/carriage unit with ink fed from the ink cartridges via
the ink refill assembly.
The major components of the ink jet mechanism (head/carriage unit shown on page 3-12 ) are:
- Front end: This is an ink-jet head consisting of piezoelectric plate (PZT), metal plates, nozzle
plate, and head driver.It jets out ink to produce images on paper.
- Back end: This consists of damper assemblies and air vent unit. Each damper assembly
dampens the ink pressure fluctuations in the corresponding ink supply tube and collects air
bubbles that result from pressure changes on the ink.
To keep the optimum head performance, the head maintenance mechanism (shown on page 3-
34 ) uses the rotational torque of the ASF motor* to cap the head nozzles in order to prevent
them from drying up. It also uses the rotational torque of the paper feed motor to purge for
removing air bubbles from the head/carriage unit and wipe off any ink remaining on the head
nozzle surface.
The carriage drive mechanism (shown on page 3-37 ) moves the head/carriage unit with a
carriage motor (DC motor) along the recording paper. The CR encoder sensor mounted on the
head/carriage unit scans the CR encoder strip and monitors the current head position relative to
the home position and the current travel speed.
The paper pulling-in, registration, feeding and ejecting mechanisms are driven by the ASF
motor* and paper feed motor (both are DC motors).
The major components are:
- Paper tray: Recording paper is stored in this tray.
- Paper pull-in rollers (shown on page 3-42 ):
These rollers pull in paper into the machine.
- Bank ASSY (shown on page 6-74 ):
This separates paper, sheet by sheet to feed it into the
printing section.
- Jam clear cover (shown on page 3-41 ):
Opening this cover allows the user to access paper jammed.
It also guides paper pulled in from the paper tray into the
printing section.
*ASF motor: Auto Sheet Feeder motor