Electro Static Discharge (ESD) and You

Electro-Static Discharge (ESD) is beginning to command more attention in the workshop situation. This is in part due to the advent of ‘smart chips’. ESD is a factor that has sometimes been overlooked in the methods used for remanufacturing the pre-chip style of cartridges and yet in some climate situations the control of ESD can become paramount in building a good cartridge. It can be beneficial to all workshops to occasionally reassess the products and processes that they use.

Experiments from school days teach us that static electricity can be generated with friction, simply by a rubbing action between 2 materials (eg. plastic ruler and a cloth) thereby creating a potential difference in electrostatic charge on the surface of objects. In this industry there are two areas to be considered as far as static electricity is concerned. These are the operation of the cartridge within the printer and the remanufacturing processes themselves.
Within normal operation of a cartridge in the Canon/HP range the OPC has friction with the recovery blade, the wiper blade and, to a lesser extent, the PCR. The mag roller has friction with the doctor blade, the retaining blade and the toner (which is itself a charged material). Many of the parts making up a cartridge have ESD potential both during their processing and also during their operation in a printing cycle.

During the remanufacturing process all of the mentioned components undergo cleaning in some way, usually involving rubbing or buffing. When third party cleaning solvents, polishes, vacuuming or blowing off with non-ionised air are added to the mix there is potential for a real increase in ESD in comparison to an OEM cartridge. It’s well documented that ESD, whenever it happens, can cause component failure and not always straight away.
Because of the friction involved in cleaning processes, potential difference of electrostatic charge on some of the components during assembly and/or operation can be outside the parameters of the normal electrostatic charge levels of a cartridge. Some third party polishes have potential to generate extra charge. ESD can happen when the potential difference of electrostatic charge occurs on two or more components. The result of this can range from damage to a PCR, to lightness of print and also pin spotting on an imaging drum.

Pin spotting tends to be blamed on poor drum manufacture, when in reality many pin spots may be a result of some work place methods, the workshop environment or sometimes the climate on a given day. After all, in some situations of very low humidity just the act of unwrapping the plastic wrap from a new drum is capable of causing an electrostatic discharge.
So as to demonstrate the potential for the buildup of electrostatic charge we have selected a number of products that are in commonplace use in many remanufacturing workshops. The products have been applied to a piece of acrylic tubing. The electrostatic charge buildup varied between 0 to more than 4,000 volts. Use of the acrylic tube will tend to exaggerate the electrostatic buildup in comparison with components such as a mag roller, but will give you a picture of the potential of some products to exacerbate ESD.

Some technicians are going to say they have used a particular product for some years with no such problem but I’m sure that most workshops have had a period of time where they experience recurrance of particular problems, such as an inordinate amount of pin spotting on new OPC’s for no obvious reason. There are many factors involved (processes, products, climatic conditions, flooring, grounded benches, wrist straps, clothing (including shoes), air-conditioning can all effect ESD) and if you can look at all of them and eliminate possible problem areas it has to be beneficial.

Below is a listing of some results of the amount of electrostatic buildup measured with a static meter……. (NOTE:- the metre is Zero on the centre line.).