ComColor Ink passage Mechanism (Revised version) RKC London Office 13 April 2010

Advantage of ink circulation system Removal of air bubble and some dust in ink Decrease cleaning time Decrease cleaning ink consumption Cool down heads by ink This system is effective for cool down heads such as car radiator. Then long time and high density printing is available continuously Improve the white line This system is able to keep fresh ink at head nozzle. (When ink viscosity will be high, white line occur easily. If old ink stay at the nozzle for long time, ink viscosity will be high)

Step1 Basic mechanism

Basic mechanism of ink circulation system Cylinder pump Negative tank Pressure tank Ink cartridge Head Difference of fluid levels

Circulation of ink ComColor print head has 2 pipes witch are flesh ink pipe and drainpipe for ink circulation Cylinder pump Negative tank Pressure tank Print head IN (flow in) OUT (flow out) Difference of fluid levels

Difference in fluid levels Negative tank Pressure tank Piezo nozzle ＜ Gravity Negative pressure for making meniscus Positive pressure for flowing down ink On the above condition, it unable to make meniscus

How to make meniscus on ComColor Pressure tank Piezo nozzle ＜ Gravity Positive pressure for flowing down ink Bellows Negative tank Negative pressure for making meniscus

How to make meniscus on HC HC series Reservoir ID unit Head Negative pressure for making meniscus Positive pressure for flowing down ink ＜ As for HC, don’t need any additional unit such as bellows

Step2 Ink level and valve condition

Main SW is OFF/Sleep Ink cartridge valve => Close Pressure tank valve => Close Negative tank valve => Open Bellows => HP Pump solenoid => Not work (close) Stayed ink Flowing ink Direction

Stand by Ink cartridge valve => Close Pressure tank valve => Close Negative tank valve => Close Bellows => Suspension Pump solenoid => Not work (close) Stayed ink Flowing ink Direction

Printing (Two tanks are full) Ink cartridge valve => Close Pressure tank valve => Open Negative tank valve => Close Bellows => Suspension Pump solenoid => Not work (close) Stayed ink Flowing ink Direction

Printing (Pressure tank is low) Ink cartridge valve => Close Pressure tank valve => Open Negative tank valve => Close Bellows => Suspension Pump solenoid => Work (open) Stayed ink Flowing ink Direction

Printing (Two tanks are low) Ink cartridge valve => Open Pressure tank valve => Open Negative tank valve => Close Bellows => Suspension Pump solenoid => Not work (close) Stayed ink Flowing ink Direction

Prepare cleaning function (For Strong creaning) Ink cartridge valve => Close Pressure tank valve => Close Negative tank valve => Open Bellows => Suspension to lower Pump solenoid => Not work (close) Stayed ink Flowing ink Direction

Normal cleaning Ink cartridge valve => Close Pressure tank valve => Close Negative tank valve => Close Bellows => HP to Upper Pump solenoid => Not work (close) Stayed ink Flowing ink Direction Actually a few ink flow via pump and pressure tank, then pressure tank ink also come out from the heads

Strong cleaning Ink cartridge valve => Close Pressure tank valve => Close Negative tank valve => Close Bellows => Lower to Upper Pump solenoid => Not work (close) Stayed ink Flowing ink Direction Actually a few ink flow via pump and pressure tank, then pressure tank ink also come out from the heads

Air valve mechanism Air flow OFF ON Side pipe Side pipe Shaft Thick pipe Shaft Thin pipe Thick pipe Thin pipe Thick pipe Side pipe Pressure tank valve Rubber cap To overflow tank To common tank Negative tank valve Side pipe ON Shaft Thin pipe Thick pipe

Step3 Swap the tank (cyan tank)

Prepare to flow down ink -From Cyan tank- Clamp the pressure tubes without Cyan. Disconnect the negative tubes and insert to overflow tank. Clamp the Cyan drain tube and insert to the overflow tank. Place some paper on the BP unit

Prepare to flow down ink -From Cyan tank- Remove the clamp at the drain tube. Ink in the Cyan negative tank will flow down slowly. When the Cyan negative tank become to empty, air bubble will come up to the pressure tank. Exchange ink in the pressure tank and coming up air.

Prepare to flow down ink -From Cyan tank- Clamp the pressure common tube. Remove the rubber black cap. Air filter tube switch from overflow tank to pressure valve (thin pipe side) When remove the clamp, ink will flow down quickly. Prevent to enter some dust through pressure tube, you should connect the air filter tube.

Replace Cyan tank -Before replacement- When two tanks for cyan become to empty, you should clamp between ink cartridge and negative tank, and also pressure air valve connection return to normal condition, disconnect the ink cartridge, and then re-connect the drain tube. After that you can remove the cyan tanks.

Replace Cyan tank -During the test mode 2711- 1)Set the test mode 2711 to “1” 2)Turn off the machine 3)Turn on it then ink supply will start 4)Ink level for negative tank will be full 5)Ink level for pressure tank will be almost full 5)Remove the three clamps 6)Head cleaning will start 6)Test mode 2711 will be “0” automatically

Fail condition 1 If the clamp for another color’s drain tube is not enough, another color ink also will flow down from the negative tank slowly.

Fail condition 2 If you forget to clamp for another color’s pressure tube, after remove the common tube, another color ink also will flow down from the pressure tank quickly. And then the negative tank will overflow, ink will come out from negative tank to overflow tank.

Fail condition 3 During the test mode 2711, if you remove the clamps before cyan pressure tank become to full condition, some air through to another pressure tank. As a result, another color tank will flow down to negative tank, and then it will overflow