User`s guide

While we are on the topic of error messages, 54.1 tells the user to remove the sealing tape from the cartridge! This is sure to be
a favorite of your customer service people. The service manual only briefly mentions this feature and does not discuss the
theory at all. We are guessing that there is still a circuit similar to the old style cartridge detection where the printer can sense
between an interior contact (possibly the new contacts in the seam of the hopper), and the magnetic roller. When no toner is
present, and the cartridge is new (probably determined by the chip) this message will come up.
The Supplies Status Page (shown on page 3) is also one of the new features on these machines. It can be printed by pressing
the “Menu Button 1x,” the “Item button 7x,” and “Select 1x.” The page itself has a visible gauge of the estimated toner left. In
addition it shows two categories: “Toner Low Reached - Yes/No” and “Toner Out Reached - Yes/No.” These settings are written to
the chip. On HP cartridges, it will also show the actual pages printed, the estimated toner use per page, and the estimated pages
left at that usage. The engine controller board actually tracks the toner usage per page, and calculates the estimated life left in
the cartridge! This is a really nice feature and one that I hope the replacement chips will enable again.
CARTRIDGE PRINTING THEORY
There are two diagrams shown on the next page, that will give a visual look at this process. The printing theory of these cartridges
is basically the same as the 4000 machines. In this article I have discussed some of the various changes and the theory behind
them. In this section, we will run though the printing process from start to finish in order of the events.
The first thing the printer does is make sure a cartridge is installed. This is done by placing a signal on the PCR. A feedback sig-
nal is returned to the printer telling it that a cartridge is present. The chip detection and toner low sensing all took place when
the printer was turned on. After all this has taken place, the actual printing can start.
The cartridge printing process is best explained as a series of steps or stages. In the first stage, the primary charge roller (PCR)
places a uniform negative DC bias voltage on the OPC drum surface. The amount of the negative DC bias placed on the drum is
controlled by the printer’s density setting. This process is called “conditioning.”
In the second stage, (also called the “imaging section”), the laser beam will discharge this DC voltage to ground wherever it strikes
the OPC’s surface, leaving a latent electrostatic image on the drum. The OPC drum’s circumference is 3.66 inches, or approxi-
mately 1/3 of a page and therefore makes three revolutions for each 11-inch printed page.
The fourth stage is where the OPC drum is cleaned. On average, approximately 95% of the toner is transferred to the paper dur-
ing the print cycle. The remaining 5% remains on the OPC drum and is cleaned off the Drum by the wiper blade, guided into the
waste chamber by the recovery blade, and stored in the waste chamber.
Once the print cycle has been completed, the primary charge roller will then place an AC voltage across the drum surface that
erases any residual charges left on the drum surface. The OPC drum is now ready to be conditioned by the primary charge roller
using the negative DC bias voltage, and start the print cycle again. The AC and DC signals on the PCR are actually done at the
same time. We have split them up to show the actual pattern of events.
All during the printing process the engine controller board has been monitoring the actual amount of toner used per page, and
calculates the estimated life left in the toner cartridge. This is shown on the supplies status page.
HP LASERJET 4100 TONER CARTRIDGE REMANUFACTURING INSTRUCTIONS
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