The People Who Made the Product byBillieJ R obi son The program manager gives credit where its due

At any given moment, all over the world, printers of various kinds attached to computers - large and small are spitting out reports, paychecks, address labels, letters, invoices, processed data nearly anything that can be printed. Much of the run-of-the-mill computer output is produced by high-speed line printers (they print a line at a time) on the z-fold 1 V computer paper familiar to many of us 11 x 15-inch sheets, plain on one side, aiternating haif-inch blue and white stripes on the...

Toner Development Curves

The performance of the toner development system, which includes machine development parameters, is shown in Fig. 3, The toner development curve shows the solid area output print density as a function of the net applied development potential. The print darkness control described in the article on page 26 automatically adjusts the toner-to-carrier ratio to achieve the desired output image density setpoint. In practice, as the developer mixture ages because of the gradual impaction or filming of...

Toner Development Model

Fig. 2, shows the cross sectional view of the layered structure and the biased magnetic roller system, A general model is shown including a fictitious air gap that is used to calculate the E-field (electric fieid) acting on free toner particles. In practice, the dielectric thickness of the mixture layer combined with the Mylar insulator overcoatingl is much greater than that of the toner layer, air gap and photosensitive layer. The photoconductive drum can also be...

Toner Development Unit Configuration

The toner developing unit, Fig. 1, consists of a stationary muitipole magnet within a biased rotating outer sleeve. The magnetically responsive carrier beads surrounding the roller assembly are metered al the N pole using a doctor blade, then carried onto the sleeve and through the development zone using the strong applied magnetic fields. In the development zone, the muitipole arrangement provides a field-free region where a toner cloud is generated between two soft brushes SI and S2. Toner...

New Fusing Method

The fusing process in the 2680A Laser Printer uses two methods of heat transfer. The paper and loner are first heated using conduction and then the toner is selectively heated by radiation to complete the fusing. The conductive heating is accomplished by a preheater system and the Selective heating of the toner by an infrared fusing system (Fig. 1). The preheater system consists of a healing plale, a vacuum source, and controlling electronics. As the web of paper with the toned image enters the...

Toner Transfer

The toner transfer system inthe2f> H )A is a corona system. A nearly constant negative charge density is applied to the paper while it is in intimate contact with the photoconductive drum containing the developed toner images. The transfer mechanism is designed to retract during ihe time when the seam area of the drum is passing under the corona, preserving essential process control markings that are used Tom Camis has been an electro photographer and praiect leader in the 2630A Laser Printer...

V

ESM block diagram Initial conditions are zeroed with the door between the probe and the drum For measurements, the door is rotated out of the way voltage across C2, Vout2 is more useful. The initial conditions of Cl and C2 are controlled by a removable door and by a reed switch across C2 inside the ESM probe (Fig, 3). The initial conditions are zeroed with the door between the probe and drum and the reed switch across C2 closed. To make a measurement, the reed switch is opened and then...

Why a New Architecture Was Needed

The DCS design team had to decide how best to realize the desired user features within an imposing framework of aggressive performance requirements. Although there are in reality many different performance limiting situations, two quite visible targets that were established early are the following 1. The DCS has to be able to print over 15,000 very small characters, excluding blanks, within an 81j*l 1-inch physical page, at 22.5 characters per inch. This is an extreme situation that can be...

Fusing System Electronics

The controlling electronics for the fusing system can be divided into two areas 1) control of input line voltage and 2) temperature control of the preheater. The fusing system has been designed to operate at 216 volts rms. This is the lowest voltage at which the 26h0a will operate. The line voltage to the fusing system is monitored by the machine control system (MCSJ. To maintain nearly constant fuser power, half cycles of the ac line voltage are clipped. For example, at a line vollage of 250...

By BiUie J Robison

A very large number of people contributed to the development ol the 2680 Laser Printing System and everyone's part was important and appreciated. However, I want to give specfal acknowledgment to a number of individuals and groups whose efforts and contributions were especially important. Roger Archibald did the fusing and effluent control system design and developmens. Dan Battazzo did the mechanical design of the paper feed and path, assisted in the final structural frame development, and...

Insulating Blocks

The corona wire must he supported by the insulating endblocks in such a way that there is no high-voltage breakdown during operation even after a long period of operation. Hreakdown can be avoided by choosing a material with good insulating properties and designing the surface topography so that there is not a short, straight path from a high voltage to ground. In addition, the voltages present are high enough that it is important to avoid edges or points with a small radius to prevent unwanted...

By Erwin H Schwiebert and Paul R Spencer

IN ELECTROPHOTOGRAPHY, the image on the paper is created in several stages, as explained in the box on page 6. This article covers the second step, that of producing the electrical image on the drum, including initializing the drum electrically. The heart of the process is the photoconductor drum, the structure of which is shown in Fig. 1. The aluminum substrate is coated with a layer of cadmium sulfide about 40 micrometres thick. On top of this is a layer of polyester about 25 micrometres...

Electrostatic Monitor

Electrostatic Monitor

Drum potentials monitored and controlled by the microprocessor system are measured by an electrostatic volt- Fig, 1. Electrostatic monitor ESM equivalent circuit The ESM is a noncontacting electrostatic voltmeter used to measure drum potentials meter. This nan contacting voltmeter measures drum potentials from 130V to 630V in a diagnostic area of the drum and scales them between 0 and 5V for ana log-to-digital conversion. If the measured drum potentials are not equal to the target values, the...