Continuous Ink System for Hp 902

Compatible with

Printer Model

HP OfficeJet 6950, 6951, 6954, 6956, 6958;
HP OfficeJet 6962;
HP OfficeJet Pro 6960, 6968;
HP OfficeJet Pro 6970, 6974, 6975, 6978;

Ink Cartridge Number

HP 902, 902XL, 906XL Ink Cartridges (United States and Canada)
HP 903, 903XL, 907XL Ink Cartridges (Europe, Middle East, and Africa)
HP 904, 904XL, 908XL Ink Cartridges (Latin America)
HP 905, 905XL, 909XL Ink Cartridges (Asia Pacific)

HP 906XL, 907XL, 908XL, and 909XL ink cartridges are not compatible with the OfficeJet 6950 series.

Printer modification and precautions

Precautions

The printing status of the pre-printed printer must be completely normal and the quality of the photo can be printed.
The modified original ink cartridge must be the ink cartridge in use, and cannot use non-original chips or ink cartridges that have been rejected by the original manufacturer.
(Rejected ink cartridges are often caused by poor contact between the chip contact point below the ink cartridge and the contact spring on the slider of the printer)
The height of the modified printer should be placed at a height of about 4 cm above the ink tank placement plane (adjusted according to the temperature and altitude of the area of use).
The modification of all related technologies of the HP 6970 printer belongs to a more complicated modification process. Please check the content of the video in sections and multiple times to avoid the flaws in the modification.
Everyone who wants to modify the printer has a different technical point of view. When you are not able to do it yourself when reading the pictures and processes of this item, it is recommended not to modify it yourself.
The content of this note is for reference only. If you can't understand the picture, please feel free to make a friendly opinion (please attach a high-level clear picture) and discuss each other.

Original Printer-Head Design

Please refer to the US Patent Document No. US008684505.
The structure of the original nozzle group that we have been neglecting. After the ink cartridge is manually filled and loaded into the support structure 50 of the printer, the printing nozzle is cleaned twice or more, and an abnormal test page still appears. The main reason is that the ink cartridge is mounted on the position of the annular seal 44 of the support structure 50, especially the air hole 62 under the annular seal 44, and the atmosphere is communicated downward and outward, causing the ink cartridge to clean the nozzle. It will introduce some outside air into the air hole 62.
When the ink cartridge is manually filled with ink, a large amount of air bubbles remain in the ink container 22, which may be caused by poor filling tools or techniques. There will be a lot of bubbles in the nozzle and it will not print properly; you need to pay attention to the filling speed of the ink, or choose the correct filling tool.
The ink container 22 installed on the upper portion of the support structure 50, if the negative pressure of the ink supply is too large, when the nozzle cleaning operation is performed, the negative pressure guides the air of the vent path 14 below the annular seal 44 into the ink hole 58 in the center of the support structure 50, and the nozzle may have a large number of bubbles, which cannot be printed normally.
If the printer is modified to CISS, the negative pressure generated by the nozzle guides the ink from the ink container 22, into the ink hole 58 in the center of the inlet tower 40, finally guides the ink into the nozzle.
The modified printer adds an ink tube above the ink cartridge to an ink supply system for the external device. The ink supply from the external ink bottle to the nozzle increases the negative pressure inside the ink cartridge. If the ink of the external ink bottle cannot be synchronously introduced into the wick 96 of the ink container 22, it enters the central ink hole 58 and the nozzle position; instead, a large amount of air is introduced into the ink hole 58 in the center of the support structure 50.
The negative pressure generated by the cleaning of the printer, in the case where the ink supply system cannot supply the ink immediately, the negative pressure directly introduces air from the air hole 62 below the annular seal 44, and the air enters the ink hole 58 of the center inlet tower 40 of the support structure 50 again；the print quality is problematic.

Modification of Printer Head Vents

We used a caulk glue, which is filled into the pores and repair with a thin needle tube and seal the air hole 62 air hole under the annular seal 44.
The caulk glue is a type of transport contraband that you need to purchase locally.
The air hole 62 under the annular seal 44 is recommended to be printed at a minimum of six hours after patching with caulk glue.

The internal structure of the original ink cartridge

Please refer to the US Patent Document No. US009452609.
The internal structure of the HP 905 SETUP, 905 Standard, 905XL ink cartridges is different, and each type of ink cartridge is modified differently.
According to the type of ink cartridge, when filling the ink cartridge, you need to select the correct filling tool. Fill your ink cartridges effectively.
To modify the type of ink cartridge for continuous ink supply, it is recommended to use a setup or standard ink cartridge.

Modify the ink cartridge

We use setup ink cartridges to modify, and other types of ink cartridges are modified using the same method.
Use a hand drill to drill a 4 mm round hole, and slowly implant the appropriate length of cotton thread the interior of the chamber, after the space of the chamberuse body is filled with the cotton thread, the cotton thread can absorb the ink, and can effectively balance the pressure generated when the printer head moves.

Ink cartridge external tube installation and fixing

A round hole is drilled above the ink cartridge, one end of the L-shaped connector is inserted with an ink hose, and the other end of the connect rod is inserted into the round hole above the ink cartridge.
On the inside of the plane above the ink cartridge, drill a round hole for maintenance. The round hole is sealed with a sealing plug, when removing or inserting the sealing plug, it is recommended to use a curved clip.
When the ink cartridge Required maintenance, remove the plug above the ink cartridge, insert the tip of the syringe into the upper through hole on the top of the ink bottle, pushing the inner cylinder of the syringe down, the air is pushed into the ink bottle, the ink in the ink bottle is guided into the ink cartridge, and the ink slowly enters the ink storage chamber of the ink cartridge.
Originally separated ink cartridges, we used a piece of film to connect four separate ink cartridges into single body with a thin double-sided tape; when the ink cartridge part required to be taken out to the outside or maintenance, the four ink cartridges can be easily lifted out as a single body.

Modification of the printer waste ink system

When the original printer cleans the nozzle, the internal ink pump is used, and two sets of gaskets are used under the nozzle to discharge the bubbles inside the nozzle by sucking the ink. The ink finally drops into the storage tank below the printer head.
We extend the end of the waste ink inside the printer to the outside and finally to a fixed ink concentration bottle.
The installation method of the ink hose between the waste ink tube and the external ink bottle should be properly installed according to the different parts and materials; it only guides the waste ink in the printer to the external bottle smoothly.
If the part materials are purchased from this website, please follow the contents of the accessories.

Continuous ink supply external balance system

Balance device design

From the other end of the ink tube connected above the ink cartridge of the printer, a set of balancing system is installed, which uses an internal micro-pressure air check valve to isolate the influence of atmospheric pressure on the ink balance system.
The stable pressure balance system maintains the balance of the ink supply system during printing after the initial installation, and maintains the balance of the ink supply system.
From the installation of the empty ink bottle to the ink guide of the ink bottle, anyone can easily achieve it without any trouble.
The balancing device installed above the ink bottle can be used to guide the ink supply to the ink cartridge by using a syringe to be inserted into the upper portion, thereby performing maintenance and troubleshooting of the ink supply system.

Micro-pressure balance device function

a seal member has two cylindrical holes, and a round hole is arranged above the ink bottle, and the round hole is provided by a seal member plugging and combining; the two cylindrical holes on the seal member are integrated into the two connect rod under the balance device body, and the balance system is inserted above the ink bottle.
The body of the balance device is provided with a micro-pressure spring, valve and valve base, and the outlet lid is integrally combined with a cover and a buckle.
The micro-pressure spring holding valve of the balance device body is in close contact with the valve base, and the ink in the isolation ink bottle is dissipated to the outside, and is not affected by the change of atmospheric pressure and affects the printing quality.
The micro-pressure spring has a very small holding force. When the printer prints the ink to produce micro-suction, the micro-suction force is sufficient to pull the valve stem of the micro-pressure spring end to move, and provide a contact surface for a micro-motion opening, for the trace air to enter the ink bottle, and then return to the close state. The action of the micro-motion opening, like the pressure of blood flow, or the phenomenon of peristalsis, allows the ink in the printing to be continuously supplied from the outside, and has a stable pressure balance and a smooth supply of ink.
The balance system is inserted above the ink bottle, and a through hole is arranged in the upper center of the balancer body for inserting the front end of the syringe. The push rod of the syringe is gently pushed, the air pushes the close relationship between the valve and the valve base, and the air is pushed into the ink bottle to guide the ink supply into the ink cartridge and to perform maintenance and troubleshooting of the ink supply system.

How to mainteance the ink Supply system

From the individual part materials, through all the combination procedures, until the ink enters the ink cartridge from the external ink bottle of the printer, the ink cartridge can be printed normally.
After the printer has been printing for a period of time, either before the ink is added, or when the printer has overprinted the ink, causing the ink supply tube of the ink cartridge to explode.
Take out the syringe and use a clip to remove the stopper above the ink cartridge.
You can recall the previous ink installation process:
- The ink cartridge is installed on the printer, and the pipeline connected above the ink cartridge extends to the outside of the printer.
- With the vent hole preset above the ink cartridge, the pressure is simply pushed by the air of a syringe. Easily introduce the ink in the ink bottle into the ink cartridge.
Finally, just a little toilet paper is placed above the venting holes above the ink cartridge. When the ink cartridge is filled with ink, a small amount of ink will overflow from the venting holes, and the overflowed ink will be adsorbed by the toilet paper in an instant.
When the ink is lacking in ink, the maintenance of the ink cartridge can be completed by the above steps.