Bubble Head Unit Structure - Canon BJC-5000 Service Manual

Part 4: Technical Reference

3.2.4 Bubble head unit structure

1) Bubble jet nozzles
The ink held by the ink sponge goes through a mesh-type ink filter and flows to the
bubble jet nozzles via the ink passage of the cartridge body.
When the head-drive current is supplied to the heater board, the ink boils and
produces several ink bubbles. Eventually, only one ink bubble is formed by boiling.
The head-drive current is turned off before an ink droplet leaves the nozzle. The
bubbling, however, continues with the residual heat of the heater and causes ink
droplets to be discharged from the tips of the nozzles.
After an ink droplet is discharged, the nozzle is replenished with more ink from the
ink sponge.
NOTE
Heater Plate
Bubble Jet Nozzle
Turning on the heater
1
While heater is on
2
3 Turning off the heater
Bubble shrinkage,
4
ink droplet formation
Ink droplet discharge
5
The heater board of the printhead holds the heater and its circuits which
are formed on a silicon plate using semiconductor technology. The silicon
plate which contains these electrical circuits is bonded to an aluminum
base. A plastic cover molded to fit the nozzles is also provided.
Extra-fine Wire
Connecting Section
Protective Bond of Wire
Connecting Section
Silicon Plate
Aluminum Plate
Faceplate (Part of plastic cover)
Figure 4-15 Bubble Jet Nozzles (Partial View)
Signal Circuit
Print Board
Ink passage from ink sponge
Joint Pipe
Plastic Cover
Common Ink Chamber
4-20
BJC-5000
Ink Filter