The soul of maintaining a new machine
books.worksinprogress.co
books.worksinprogress.co
Xerography was once a very touchy process. It took insane complexity and skilled technicians to make xerography go in the selenium drum era. The basic idea of xerography is that you charge up a photosensitive surface which is discharged by light. So the original is projected onto a selenium drum, and the light areas are discharged. The remaining charged areas will attract toner, which is then rolled onto paper. The final step is heat-fusing the toner to the paper. Then the drum is cleaned and recharged for the next page.
It's amazing that this works at all. It barely did in the selenium drum era, which is what this article is about. Selenium is very soft, and not a very good photoconductor. Around 1990, selenium was replaced with multi-layer organic photoconductors, and the process became much more robust. That resulted in smaller, cheaper, and less maintenance-intensive xerographic copiers and printers. Now, anybody can change the toner cartridge.
That's why Xerox needed so much technician know-how. The selenium drum machines needed a lot of tweaking. Sort of like 1950s cars or TVs, which needed lots of screwdriver adjustments. As the technology matured, it became idiot-resistant, or at least field-replaceable without adjustments.
This is how technology progresses, from fussy to robust. At the fussy stage, you need people who really understand how it works and how it breaks. At the robust stage, you have minimally trained part changers. They're viewed as under-qualified by the old guard, and as cheaper by management. Watch for this pattern as new technologies are adopted. It's happening to programming right now.
> “I wouldn’t characterize it as annoying,” Vicki Warner, who leads a team of printer engineers at Xerox, said of discovering a new kind of paper jam. “I would characterize it as almost exciting.” When she graduated from the Rochester Institute of Technology, in 2006, her friends took jobs in trendy fields, such as automotive design. During her interview at Xerox, however, another engineer showed her the inside of a printing press. All Xerox printers look basically the same: a million-dollar printing press is like an office copier, but twenty-four feet long and eight feet high. Warner watched as the heavy, pale-gray double doors swung open to reveal a steampunk wonderland of gears, wheels, conveyor belts, and circuit boards. As in an office copier, green plastic handles offer access to the “paper path”—the winding route, from “feeder” to “stacker,” along which sheets of paper are shocked and soaked, curled and decurled, vacuumed and superheated. “Printers are essentially paper torture chambers,” Warner said, smiling behind her glasses. “I thought, This is the coolest thing I’ve ever seen.”
[1] https://www.energy.gov/articles/history-air-conditioning
I once had a shouting match with senior management of an East Coast company I worked for because they wouldn’t do what was necessary to avoid an experienced Sales Engineer from leaving. To them these were “headcounts” you just replaced when they left, zero understanding of the years of accumulated undocumented knowledge that would walk out the door. Literally the difference between successful deployments and catastrophes that required expensive fixes and escalations. MBA thinking at its finest.
We are doing here, and most brilliantly, doing what Xerox technicians did back then, and that the scholars that worked in the infinite corridor at MIT have done, and do now.
Thank you!