Epson Scan 2500 service manual Printing Mechanism, PF motor, Pump unit

EPSON Stylus Scan 2500

Revision A

PF motor	Disengage
		flag
pinion
Intermittent
gear
PF Motor
Flushing section
Star wheel
Disengage flag
Black I/C sensor
CMY I/C sensor
Carriage unit
Printhead
(one unit)
Timing belt
Cap unit

73.6 Gear/Precision Gear

ASF sensor

Detector wheel

Loading

shaft

Loading

rollers

PE sensor

Carriage HP sensor flag

2.2.1 Printing Mechanism

The basic principles of the printhead are the same as previous models; Drop- On-Demand type MACH head method.

You need to manually input the drive-voltage code (printed on top of the printhead) for the multi-layer piezo electric element. Input this value every time you replace the printhead, MAIN board, or printer mechanism.

The main parts of the printhead and carriage are described below.

	PZT
	PZT is an abbreviation of Piezo Electric Element. The print signal is
	sent from the MAIN board to the PZT via the driver circuit on the
	printhead unit. Then, the appropriate PZT squeezes the cavity, forcing
	the ink stored in the cavity out through the nozzle. This process is
	described in more detail on the next page.
	Ink cavity
	Ink flows from the ink cartridge, through the filter, and to the ink
	cavity where it is stored until one of the PZT units forces it out through
	the nozzles.
	Nozzle Plate
	The bottom surface of the printhead which contains nozzle holes to
￿	direct ejected ink toward the paper below. See the next page.

Pump unit	Carriage HP
	sensor
CR guide shaft	CR Motor
PF roller
	PG lever

Figure 2-1. Printer Mechanism Block Diagram

Filter

When the ink cartridge is installed, if any dirt or dust around the

cartridge needles is absorbed into the inside of the printhead, there is

a large possibility that the nozzles will clog. Clogged nozzles can be

detected by alignment failure and dot-missing problems. To prevent

these kinds of problems, a filter is set below the cartridge needle and

ink flows through the filter on its way to the ink cavity.

Operating Principles Printer Mechanism Operation 35