Overview
This section describes the operating principles of the printer mechanism and electrical circuit boards. The Stylus PHOTO 895/785EPX has the following boards:
□ Power supply board: C408 PSB/PSE
□ Monochrome panel board: C408 PNL
□ Printer panel board: C408 PNL-B
2.1.1 Printer Mechanism
The printer mechanism for Stylus PHOTO 895/785EPX is designed newly. But, the basic component of the printer mechanism is same as previous product. This printer consists of Print Head, Carriage Mechanism, Paper Feeding Mechanism, Paper Loading Mechanism, Ink System (Pump Mechanism, Cap Mechanism, and Carriage Lock Mechanism).
Like other EPSON ink jet printers, the Stylus PHOTO 895/785EPX is equipped with three stepping motors; one for ASF/Pump mechanism, one for Paper feeding mechanism and one for carriage mechanism. ASF unit uses rear entry front eject system. This ASF unit is also designed so that the single LD roller loads the paper to the printer mechanism. For cap assembly, Stylus PHOTO 895/785EPX uses valveless mechanism.
- Figure 2-1. Printer Mechanism Block Diagram
2.1.2 Printhead
The printhead uses a new developed U-CHIPS head and Stylus PHOTO 895/785EPX can perform multiple shot printing and variable printing.
The CSIC is mounted on the ink cartridge. By storing ink life data, this IC makes it possible to control the ink in ink cartridge unit.
The basic operating principles of the printhead, which plays a major role in printing, are the same as previous models; on-demand method which uses PZT (Piezo Electric Element). In order to uniform the amount of ejecting ink, the printhead has its own head ID (13 digits for this printhead) which adjust PZT voltage drive features. The printhead stores the head ID to EEPROM and generates appropriate PZT drive voltage to prevent amount of ink from varying by printheads.
Following explains printhead basic components.
PZT is an abbreviation of Piezo Electric Element. Certain amount of voltage expands and contracts PTZ. The drive wave generated on MAIN board drives PZT and PZT pushes the top cavity which has ink stored to discharge the ink from each nozzle on the nozzle plate.
The ink absorbed from the ink cartridge goes through the filter and then is stored temporarily in this tank called "cavity" until PZT is driven.
The board with nozzle holes on the printhead surface is called Nozzle Plate.
□ CSIC Connection Circuit
This circuit connects the CSIC mounted on the ink cartridge and the main board. One end of the wire harness connects with the print head cable to the main board.
When the ink cartridge is installed, if any dirt or dust around the cartridge needle is absorbed into the head, there is a great possibility of causing nozzle clog and disturbance of ink flow, and finally causing alignment failure and dot missing. To prevent this problem, a filter is set below the cartridge needle, where ink is filtered.
- Figure 2-2. Printhead Sectional Drawing
□ Nozzle Layout
Black: 48 nozzles (120 dpi)
Color: 48 nozzles x5(Cyan, Magenta, Yellow, Light cyan, Light magenta)(120dpi) The nozzle layout when viewed from the back surface of the head is shown below.
2.2578(32/360inch) 2.2578(32/360inch) 2.2S78(32/360inch)
7.902(112/360inch)^
7.902(112/360inch)^
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