Basic Toner and Developer Storage, Handling, and Replacement Guidelines
Although everyone in the business equipment industry is familiar with toner, it’s surprisingly common to experience performance problems that could be avoided by following some basic guidelines. It is also important to educate end-users on some of these simple concepts.
Here, we present some easy-to-remember guidelines for storing and handling toner. Also, those of you who are somewhat new to the copier side of the business may benefit from information on the role of developer in a dual-component (toner/developer) system, and the importance of replacing developer at the appropriate, OEM-recommended intervals.
Keep It Cool and Dry!
High heat and excessive humidity have extreme adverse effects on toner and developer. If you’ve been in this industry for a long time, you may consider that statement “common knowledge.” But it is surprising how common it is for heat and humidity exposure to affect these products, and for end-users or even service technicians not to recognize the source of their problem when it happens.
What does high heat do to these products? In essence, it causes toner particles to stick together (“agglomerate”). Remember that developer, too, contains toner in addition to carrier- so the physical reaction is the same. If the heat is high enough, or the product’s exposure to it long enough in duration, the toner or developer will not perform acceptably in its intended machine application. The results can be inadequate dispensing of the toner, background on copies, and even development unit seizure if the situation is extreme.
A simple connection helps explain why humidity adversely effects these supplies. We must remember that the entire xerographic process is based on the behaviors of electrostatic forces. In more common terms, static electricity is stronger and more observable in a dry environment (a carpeted room on a cold winter day, for example) than in a moist environment. This is why you seldom “get a shock” by touching an object after walking on carpeting in warm, humid spring and summer months, but this does happen when the overall environment is drier.
Just as an extreme environmental condition affects other physical forces, it impacts whether toner particles charge to their specified levels. Generally speaking, toner exposed to high humidity for a lengthy period of time may never receive and retain a high enough triboelectric (static) charge to perform properly. In dual-component systems, this causes increased toner development on the photoreceptor and dark copies or background; in monocomponent systems, the opposite is likely: reduced toner development and light copies. The adverse effects aren’t only image quality-related, either — for example, over-developing reduces the toner yield as well.
Throughout the supplier/dealer/end-user distribution cycle, occasional reminders to keep toner cool and dry are appropriate. This simple “rule of thumb” can prevent problems from occurring, or clear up the mystery when heat or humidity exposure has damaged a product.
A Whole Lot of Shakin’
When is agitation a good thing? Certainly not when your customers are experiencing it… our answer is “when it occurs due to proper shaking of a toner cartridge or bottle prior to installation.”
For an end-user responsible for installing toner, shaking the cartridge or bottle thoroughly is often the first step in achieving optimum, problem-free toner performance. Some OEMs even recommend pounding the cartridge on a hard surface numerous times. Such actions improve the toner’s dry flow characteristics, ensuring it will be dispensed properly and completely. It also helps ensure that proper mixing and charging of particles can occur within the developing unit.
What can happen if the toner isn’t shaken before installation? A reduced toner yield is one possible outcome, and that will increase supplies costs for the machine. Image quality problems such as unacceptably light or dark areas on copies can also result.
End-users who follow the installation instructions provided on the toner box or instruction sheet – including proper agitation of the toner – will get the best possible results.
On-Time Developer Replacement Helps Guarantee Consistent Image Quality
In dual-component-based developing systems, the primary reason for replacing developer (which is a mixture of carrier and toner) is to prevent substantial image quality variations caused by carrier failure.
The carrier coating’s primary function is to provide an appropriate surface for proper charging of the toner. Any changes to that surface consequently affect the toner’s charge level. Such changes in toner charge disrupt the precise, delicate electrostatic balance within the developer. In doing so, they may create noticeable image quality variations. Carrier failure generally occurs as a result of either: (1) permanent adherence of numerous toner particles to the carrier surface, or (2) gradual wear and abrasion of the carrier coating. Neither is preventable; both are normal events as copies/prints are made using a dual-component development system. The only solution is periodic replacement of the developer, which inserts “fresh” carrier (and toner) into the system.
Copier/printer OEMs evaluate developer performance in the machines they manufacture, and recommend developer replacement intervals accordingly. Although it is tempting for the dealer to try to substantially “extend” developer life to reduce supplies costs – especially in cost-per-page accounts – this is a highly questionable practice. Any savings can be quickly wiped away when use of developer beyond its recommended yield results in reduced toner charging, reduced toner yields, and increased toner dusting within the machine. Customer dissatisfaction with these results will, in fact, wipe those savings away in a hurry.
Along with your choice of a reliable supplier of quality, cost-effective imaging supplies, your most important toner/developer-related decisions may be your most basic ones. In this case, as in so many others in our industry, a little education on the fundamentals goes a long way toward your continued profitability.