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Continuous Ink Supply System (CISS): A Basic Printing Guide

What is a Continuous Ink Supply System for Printers?

Continuous ink supply system (CISS) refers to a device on the market that is modified for inkjet printers and can provide continuous ink supply. This starts with the ink cartridges of inkjet printers. In the past, when people used inkjet printers, they often complained that the ink cartridges were too small and ran out of ink within a short time of printing. This consumable was not durable. Buying new ink cartridges costs tens to hundreds of yuan, which is a big expense.

The continuous ink supply system is a new ink supply method that has only appeared in the field of inkjet printers in recent years. It uses an external ink bottle and then connects it to the printer’s ink cartridge with an ink tube so that the ink bottle continuously supplies ink to the ink cartridge, which is the so-called “continuous supply”. The biggest advantage of the printer with a continuous ink supply system is its affordability, which is much cheaper than original ink. Secondly, the ink supply capacity is large and it is convenient to add ink.

Generally, the capacity of one color is 100ml, which is at least 5 times more ink than the original ink cartridge. The quality of its three-continuous ink supply is steadily improving. Better continuous ink will not block the nozzle, and it can be cleaned several times if there is a disconnection. This provides a strong guarantee for the survival and development of the continuous supply.

Continuous Ink Supply System (CISS)

4 color CISS UV with 4 cartridges

How Does a Continuous Ink Supply System Work?

Most continuous ink supply systems apply the siphon principle, that is, in two containers filled with liquid and connected by a siphon tube, the liquid always flows from the container with high pressure into the container with low pressure. We know that during the printing process, the printer’s ink cartridge will continuously deliver ink to the printhead. While delivering ink, the pressure inside the ink cartridge is also decreasing. The same volume of air needs to be sucked in to maintain pressure balance. The continuous ink supply system replaces the air supplied from the vent hole of the ink cartridge with ink. While the ink cartridge delivers ink to the printhead it also replenishes the same volume of ink. The ink replenished into the inner ink cartridge is supplied by an external large-capacity ink tank through a hose. The external ink tank can replenish ink at any time, thus ensuring that the ink cartridge in the printer always has enough ink supplied to the printhead.
In addition, there is also an automatic ink supply system that uses the capillary principle of fluid mechanics. According to the manufacturer, its ink supply is more stable than the siphon continuous supply system and can be applied to all types of inkjet printers. The actual effect of this product has yet to be tested.

Continuous Ink Supply System Structure

From the principle of the continuous ink supply system, we know that the continuous supply system is composed of three parts: the outer ink cartridge (ink bottle), accessories such as hoses and brackets, and the inner ink cartridge (ink damper).

1. Outer Ink Tank

The outer ink tank is a large-capacity ink container placed outside the printer. It is usually made of plastic injection molding. The capacity of the outer ink tank is larger, usually more than 100ml per color. There are also small-capacity continuous supply systems specially prepared for home users, and the capacity is about 50ml per color. The outer ink tank generally has an ink filling hole to facilitate replenishing ink, and a ventilation hole to maintain pressure balance inside and outside the container.

For the outer ink tank, controlling the ink level is a very important issue. If the ink level is too high, the pressure in the outer ink tank will be too high, causing the ink to flow into the waste ink tank in the printer and be wasted. If the surface is too low, the ink in the inner ink cartridge will flow back to the outer ink tank through the tube, causing air to enter the inner ink cartridge from the printhead, causing tiny bubbles to be generated in the ink cartridge, and these tiny bubbles will cause printing disconnection. To avoid these problems, the ink level in the outer ink tank is usually required to be slightly lower than the printer nozzle.

However, as the ink is consumed, its ink level will continue to decrease, which requires timely adjustment of the height of the outer ink tank, or at any time to replenish ink. To solve this problem, many manufacturers have designed a pressure-regulating device on the outer ink tank For example, some manufacturers use springs, and some manufacturers use the principle of atmospheric pressure to add a balance chamber to the ink cartridge for automatic pressure regulation, so that the liquid level can be kept constant. The outer ink tank that uses automatic pressure adjustment is called a constant-pressure ink cartridge. It can be directly fixed on the printer casing and is very convenient to move.

2. Hose

The hose is also called the drain pipe. It is the pipe that transports ink from the outer ink cartridge to the inner ink cartridge. It is actually a set of siphons that connect the outer ink cartridge and the inner ink cartridge together in one-to-one correspondence by color. In order to facilitate wiring, the hose is usually 4 or 6 pipes glued in a row, and there may be various brackets or fixing blocks on the hose to facilitate installation and fixation. In addition, some manufacturers also add an ink control valve to the hose to control the on/off and flow rate of the ink.

inkjet printer continuous ink supply system

4 color CISS (1.5L) with 4 cartridges horizontal

3. Inner Ink Cartridge

The ink cartridge installed inside the printer is called an internal ink cartridge. Its size and shape are similar to the original ink cartridge. It can be installed in the ink cart of the printer to replace the original ink cartridge (there are also internal ink cartridges modified with original ink cartridges). They cannot be used universally, and specific models of internal ink cartridges can only be installed in specific models of printers.
The inner ink cartridge is a very critical part of the continuous ink supply system. It must not only ensure the continuity and smoothness of the ink supply but also prevent ink leakage. This is a difficulty in the design and production of the inner ink cartridge. Most internal ink cartridges around 2009 used sponge-free ink cartridges. Compared with sponge-based ink cartridges, the ink is less likely to produce bubbles and it is more difficult for air to enter the nozzle. The problem of disconnection after installing and removing the ink cartridge is reduced, and the service life is also longer. Its disadvantage is that it easily leaks ink.

There are also some manufacturers whose inner ink cartridges do not use conventional ink cartridge designs, but use ink dampers, which almost connect the hose directly to the ink outlet of the ink cartridge. This design makes the installation of the inner ink cartridge easier the installation is simpler and the wiring is more convenient.
All continuous ink supply systems or automatic ink supply systems are mostly composed of these three basic components. The difference between them is mainly the difference in the internal structure of the inner and outer ink cartridges, as well as the difference in workmanship and shape. The continuous ink supply system is basically a product where “details determine success or failure”. In many cases, we can tell whether it is good or bad with the naked eye. A good continuous ink supply system must be a product with good materials, fine workmanship, and a beautiful appearance.

Ink Used for CISS

There is no doubt that ink plays an important role in the continuous supply system. The cost advantages and effects of the continuous ink supply system will ultimately be reflected through ink. In 2010, all bottled inks on the market for desktop printing were compatible inks produced by third-party manufacturers. The development and growth of the continuous supply market are inseparable from the maturity of compatible ink technology.
Inks are classified according to solvents and can be divided into two types: water-based ink (using water and water-soluble solvents as the main components of dissolved color base) and oil-based ink (using non-water-soluble solvents as the main component of dissolved color base); if according to color base on the classification, it can be divided into dye-based ink (ink with dye as color base) and pigment-based ink (ink with pigment as color base).

This means that some pigment-based inks may be either water-based or oil-based inks, but currently, the most commonly used are water-based dye-based inks and water-based pigment-based inks. The most commonly used in continuous supply systems is water-based pigment-based ink. Inks with different solvents and color bases cannot be mixed in the same ink cartridge, nor can they be mixed in the same continuous ink supply system. The most ideal situation is that a continuous supply system only uses the same brand of ink and the same type of ink to prevent problems caused by mixed ink.

Continuous Ink Supply Printer

What is a CISS printer? CISS printer refers to a device on the market that is modified for inkjet printers and can provide continuous ink supply. Theoretically, all inkjet printers can use the continuous ink supply system, but most of the current mature continuous supply products are designed for Epson inkjet printers, and some are designed for Canon’s split ink cartridge models. The continuous ink supply systems for HP printers are relatively rare, and the technology is not mature enough.

The main reason for this situation is that most of Epson’s printers use split ink cartridges, and it is relatively easy to modify the continuous supply system. Moreover, Epson’s micro-piezoelectric printheads have a long life, and the value of modifying the continuous supply system is great. Most Canon and HP inkjet printers use integrated ink cartridges, which are difficult and costly to modify. Moreover, the thermal foam printheads they use have a short lifespan, which reduces the value of modifying the continuous supply system.

Since the cost-effectiveness of the continuous ink printer is very obvious, it also has great benefits for users of Canon and HP inkjet printers. Continuous supply system manufacturers are definitely not willing to let go of this huge market. Therefore, many manufacturers are also developing continuous ink supply systems for Canon printers and HP printers. Such continuous supply systems are constantly being launched on the market. For Canon and HP printers, The prospects for applying an inkjet printer continuous supply system on the Internet are still very optimistic.

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