GB2495267A

GB2495267A - Ink storage unit for a continuous inkjet printer

Info

Publication number: GB2495267A
Application number: GB201112998A
Authority: GB
Inventors: Paul Jerome Banks
Original assignee: IMAGE ALCHEMY HOLDINGS Ltd
Current assignee: IMAGE ALCHEMY HOLDINGS Ltd
Priority date: 2011-07-28
Filing date: 2011-07-28
Publication date: 2013-04-10
Also published as: GB201112998D0

Abstract

An ink storage unit 4 for a continuous inkjet printer comprising an ink supply port, an ink refill port 3 and a breather hole 1. The ink supply port has a stopper 2 that is pierced by a needle of an ink delivery duct (Fig.1) which transfers ink for the ink storage unit to the printhead. The breather hole 1 allows air to enter the ink storage unit 4 and the refill port 3 is used to refill the ink storage unit 4 when ink in the unit is depleted.

Description

This invention relates to improvements in or relating to an ink delivery arrangement.

It is usual for printers for use with personal computers (PC5) to be either of ink jet type, in which ink from a reservoir is fed to the surface to be printed in accordance with requirements, or a laser type in which ink in a non-liquid form (toner powder) is transferred to the surface to be printed and in accordance with requirements is fixed on to a substrate to give the desired image.

Generally, in documents that require multi-colour printing, an ink jet form of printer might be more likely to be used due to greater resolution of images that can be printed and the ability to produce a photographic effect output. However for volume printing, it has generally been believed that a laser printer is faster due to the manner in which the image is formed. Recent developments in inkjet and digital printing have made considerable improvements and now challenge laser printing technology.

More recently it has become more common for users of printers to use an ink jet form of printer which is fed by a reservoir of either different coloured inks or alternatively monochrome inks of varying dilutions so as to produce a range of tones, forming a so-called "continuous ink supply" system. A system of this type provides within the printer itself, a cartridge reservoir for each of the different colours or ink dilutions available but rather than being sealed, they are supplied by an external reservoir of ink which is linked so as to be able to supply ink from the external reservoir through a delivery tube into the appropriate cartridge reservoir in the printer itself to form a supply mechanism.

Continuous ink supply systems (CISS) are usually regarded as being a cost effective method of delivering ink to computer printers as compared to the practice of changing individual ink cartridges, whether this be full colour or monochrome printing, as required.

Furthermore, it is clear that such a system for supply of inks generally allows for a greater ink capacity and therefore requires less frequent refilling. The economies of scale of CISS afforded by purchasing bulk inks for such systems is a significant advantage over the purchasing of individual cartridges.

Whilst CISS are efficient and cost-effective, a number of the systems commonly used are completely integrated such that a delivery tube which extends from the main ink reservoirto the modified cartridge within the printer is continuous and cannot be easily separated. As a consequence of this, the CISS are printer specific and cannot be used interchangeably with different printers. This reduces the cost effectiveness of the system significantly.

There may also be a problem with existing CISS methods and specifically the ink delivery tubing, interfering with the internal mechanisms of the printer during normal operation.

The obstruction of the mechanism by the ink delivery tubes may cause damage to both the printer and the CISS, resulting in expensive repairs or replacement of equipment.

It is usual for cartridges used within a printer to have an OEM microchip that monitors the use of the printer cartridge in order to provide an estimate of the level of ink remaining within the cartridge. When the microchip detects that the cartridge has performed a pre-determined number of print cycles a notification is usually displayed either on the printer itself or the computer it is connected to or both, informing the user that the ink level in the cartridge is sufficiently low to require a replacement of the cartridge. As the microchip is only able to estimate the remaining ink quantity within the cartridge on the basis of performing a pre-determined number of print cycles, it is possible that the notification may be displayed even if there is still sufficient ink remaining within the cartridge, however it is usually necessary to install a new cartridge as the printer is unable to recognise the actual quantity of ink remaining due to the limitations with the OEM microchip. The OEM microchip on the cartridge may be reset by removing it from the printer and using an electronic resetting device, but this process is not only time consuming and messy, but also risks the introduction of air and contaminants into the system.

Many CISS employ an Auto Reset Chip (ARC) to counteract the aforementioned problem of the usage limitations with the OEM microchip. The ARC automatically resets itself after a certain number of print cycles or by the printer being switched on, rather than the process having to be performed manually, thus allowing uninterrupted use of the CISS as the ink levels within the printer cartridge are never reported as being insufficient by the microchip.

Often, refillable cartridges use the ARC microchip, but because the chip never shows "empty", there is a risk that the cartridge could run dry and thereby damage the printer print head.

A further problem with commonly used 0155 is that installation of these systems and connection and reconnection to refill the system can be time consuming and also messy which reduces the functionality and attractiveness of the system as a simpler and more cost-effective solution.

In addition, one of the problems associated with the bulk storage of pigment inks which may be used in 0155 is that of particle agglomeration within the ink solution. Pigment particles have a tendency to drift towards each other in solution and combine to form larger particles. These larger particles settle towards the bottom of the container as they are larger and heavier than the non-agglomerated particles and create an ink density gradient within the solution. Such a density gradient is highly unsatisfactory as not only may the pigment density gradient compromise print quality, the larger sized partictes also pose the risk of obstructing the tubing (thrombosis) and the printer print head nozzles thus impairing the functionality of the printer or the CISS.

Additionally, the gases contained within the ink can come out of solution when in the tank and, more problematically, in the tubing, causing breaks in the continuity of the flow of the ink and these air pockets can lead to foaming in the cartridge, which can compromise print quality.

It is an object of the present invention to provide an improved continuous ink supply apparatus which overcomes or at least minimises the above-mentioned problems associated with existing arra ngements.