Remanufacturing the HP 4100: Toner Cartridge (C7115A)
by Tim Farrell and Technical Staff - Faroudja Toner

    The HP LaserJet 4100 series printers are Hewlett-Packard's latest and greatest mid-level machines to date. They are packed with new features and are extremely fast. With a street price less than the 4000 series, the 4100 series is going to be very popular.

    This article is going to throw a lot of information at you. Because these cartridges, as well as the new technology used in both the cartridges and the machines, are sure to be with us a while, we have tried to fill this article with as much information as we could.

    The Hewlett-Packard 4100 Series packs in new features, including chip that tracks toner consumption information for the OEM catrtridge.

    Engine Overview

    The HP 4100 series is based on a Canon 25-ppm, 1200-dpi engine. This engine uses the HP PCL-6 language and outputs the first page in under 15 seconds. With direct access to a TCP/IP network, these printers can notify anyone the user selects when the toner is low or there is a problem.

    There are two cartridges available for the 4100 series. The C8061A (6,000 page yield) and the C8061X (10,000 pages). Although these new cartridges look like the 27A and 27X cartridges, they are different and only a few 27x parts will work in these cartridges.

    The 61A and 61X cartridges also have the distinction of being the first HP toner cartridges to use a chip. The chip is not a lock-out device; it monitors the toner usage (see Figures 1 and 2). For example, once the machine sends a "Toner Out" signal to the cartridge, the chip is set for "Yes" for Toner Out as indicated on the supplies status page (more on that later). When the cartridge is remanufactured, the display will show "Non-HP Cartridge."

    Figure 1

    Figure 2

    The toner gauge will still work, but will no longer be accurate and the "Toner Low Stop" indicator will no longer function. In other words, the printer will continue to print even if there is no toner left in the remanufactured cartridge. The toner low/out warning on the display will not disappear until a new HP cartridge is installed. Therefore, it is very important to educate your customers about this before they use your cartridges. Even after "new" HP cartridges are installed, it may take as many as 20 pages before the new cartridge is acknowledged.

    If the chip is removed, the "Toner Low/Out" warning will not show on the display, but, once again, the machine will not recognize a toner low condition until a new HP cartridge is installed.

    As per the HP 4100 user's guide, "When you use a non-HP cartridge, the printer is unable to report on the number of pages that can be printed with the amount of toner left in the cartridge. The toner level estimate will only be an approximate percentage."

    Also according to HP, the "Toner Out" message will only appear when less than 1 percent of the toner is left in the cartridge. This is much more accurate than any previous system.

    At the time of this writing, a new replacement chip is just being released that should enable the toner low and usage functions to work with remanufactured cartridges.

    One interesting note: So far we have tested two new HP C8061X cartridges to ASTM standards. On both cartridges we ran out of toner at approximately 8,800 pages. We are using a 5 percent page set up for the HP 4000 so we weren't surprised at the low page count (this page does not produce exactly 5 percent on the 4100).

    The surprise came when we ran the supplies status page (see Figure 3a and 3b). It listed our overall page coverage at 5 percent with less than 100 pages left in the cartridge! So much for a 10,000 page yield at 5 percent coverage! We are continuing to run tests and will keep you posted.

    Figure 3a

    If you already own an HP 4000, you CAN test the 4100 cartridges in it. The 4100 cartridges are backward-compatible, as noted in the HP service manual. However, if testing your cartridges to ASTM standards, you must use the 4100 printer. The electronic components in the 4100 differ enough from the 4000 to cause a significant change in results.

    The HP 4000's large drum gear has 60 teeth, while the 4100 has 62. The 4000 machines are tolerant of the extra teeth, but damage will occur to the printer if you use a 4000 drum in the 4100.

    If you test your cartridges with Anacom Smartboxes in a 4100, the boxes will not work with the current Eprom version installed. The printer has a "hot" interface that watches both the USB port and the Parallel port. This allows you to hook up two computers to it at the same time, and one of them can even be a Mac! Unfortunately, it also seems to need specialized information from the new driver before it will accept the print job. I have been assured that new Eproms are in development for the Anacom boxes that will work for both the 4100 and the 1200 series (the 1200 series of printers have the same type of interface).

    Splitting these cartridges will not be easy because there are new contacts that sit directly between the two halves. Hand splitting is possible, but definitely not a fast process. Splitter manufacturers are working on solutions now and may be available as you read this.

    According to the HP manual, a cleaning page should be generated and run each time a cartridge is replaced or if small dots start appearing on the page. The cleaning page can also be set up to run automatically. For more information on how to generate and use this page, see page 62.

    HP 4100 Is Packed with New Features

    Normally we don't detail a machine's capabilities, but the 4100 has so many new features and changes to old features we felt it necessary.

    The EEPROM cartridge chip is located on the front edge of the cartridge and is called the "Elabel" by HP (see Figure 1). It is accessed by what HP calls the "Antenna Unit." This antenna unit reads and writes to and from the chip. There are no physical electrical connections on the chip. It communicates by what I believe are radio frequency signals.

    The HP service manual is curiously silent on this. The antenna unit is controlled by the "memory controller printed circuit board (PCB)," which in turn is controlled by the "engine controller board." The engine controller board seems to be the new name for what we all know as the DC controller. If you also do printer service, there are a few new PCB's with which to contend (see "Cartridge Printing Theory" on Page 64).

    Another change in these machines is the way in which the cartridge is detected. Older cartridges have an antenna bar that receives a signal through the toner from the magnetic roller. The signal in the 4100 machines comes from the PCR. A returned feedback signal tells the printer if the cartridge is present or not.

    Since the PCR is the first cartridge component accessed in the print cycle, this actually makes more sense than using the mag roller system. The power supply will never put out any voltages under a "no-load" condition. If you forget to reinstall the PCR or have a bad PCR connection, this will probably prompt a "No Cartridge" message.

    Fuser and Environmental Temperature Settings

    The fuser assembly is of the "instant on" variety and heats up to 383F during normal printing. The fuser temperature is variable through the menu for different types of paper/transparencies. Furthermore, a new fuser sensor in the 4100 series actually measures the ambient room temperature! The environment temperature sensor, or TH3, is located on the left side of the printer. Its purpose is to measure the temperature of the ambient environment and adjust the fuser temperature accordingly. There are three conditions that the sensor detects.

    • Low Temperature: When air temperature is 63F (17C) or lower
    • Normal Temperature: When air temperature is 63 to 88F (17 to 31C)
    • High Temperature: When air temperature is 88F (31C) or higher

    This feature presumably will allow the machine to operate in somewhat extreme environments with better results. If this sensor fails, the printer will signal a 58.2 error.

    Customer Service's Favorite Error Message

    While we are on the topic of error messages, 54.1 signals 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 behind it. I am guessing that there is still a circuit, similar to the old-style cartridge detection, that allows the printer to detect 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 54.1 message will come up.

    Supplies Status Page

    The Supplies Status Page (see Figure 3a-b) is another new feature on these machines. It can be printed by pressing the Menu button one time, Item button seven times, and Select one time. A graphic gauge notes 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 address.

    Hewlett-Packard LaserJet 4100 Remanufacturing Instructions

    Required Tools
    Toner-approved vacuum
    Dremel tool with grinding bit
    Small common screwdriver
    Small L-shaped allen wrench
    Phillips head screwdriver
    Needle nose pliers
    Required Supplies
    Mag roller sleeve (when available)
    Doctor blade (HP 4000)
    OPC drum (when available)
    Wiper blade (when available)
    PCR (HP 4000)
    99 percent Isopropyl Alcohol
    Magnetic roller cleaner
    Kynar padding powder
    Can of compressed clean ai
    Lint-free cotton pads
    PCR cleaner
    Conductive grease
    WARNING: Always wear safety goggles and breathing mask when working with or around toner. Do not disperse the toner into the air. Use approved toner vacuums and filters at all times.

    1. Place the cartridge with the drum side up. Note on each end of the cartridge, there are small silver pins similar in size and location to the 4000 pins. To separate the two halves, these pins must be removed.

    Unlike the 27A and 27X cartridges, these pins are sealed off on the inside of the cartridge. The methods you use for the 4000 will not work. This is obviously an attempt to make remanufacturing more difficult, but with the proper tools, is easily overcome.

    2. Remove the two Phillips head screws, and the metal axle pin located on the right side of the cartridge.

    Figure 4

    3. Remove the two screws and the plastic drum end cap from the left side of the cartridge.

    Figure 5

    4. Remove the OPC drum being extremely careful not to scratch it. If the drum is in good shape and you plan to re-use it, vacuum any toner and debris from drum being careful not to let the vacuum hose come in contact with the drum surface.

    Figure 6

    5. Carefully remove the Primary Charge Roller (PCR) by gently prying it out of the clips on either end. The PCR Holders come loose easily! Be very careful with this. Place the PCR aside.

    Figure 7

    6. Take the Dremel tool with the grinding bit and carefully grind off the caps covering the pins. The caps were carefully cut off with a razor knife. This was done for the purposes of this article only so that we could show them to you. Grinding is much easier and faster.

    Figure 8

    Figure 9

    7. Using a small Allen wrench, gently push both of the silver pins out from the inside of the cartridge. Note that the head of the pins are enlarged; this is why they must be tapped out from the inside.

    To make this process easier, push the pins out half way, and pull them out from the outside with needle nose pliers. If you push the pins in from the outside of the cartridge, you will damage the cartridge shell and the support bracket to the PCR roller. Separate the two halves.

    Figure 10

    8. Remove the two screws and the wiper blade. Clean out any waste toner from the chamber.

    NOTE: Be very careful not to damage or distort the thin mylar recovery blade next to the wiper blade. If this blade is bent or damaged in any way, it should be replaced.

    Figure 11

    NOTE: Although this wiper blade looks very similar to the 4000 wiper blade, they are different and not interchangeable.

    9. Due to the aggressive nature of the toner used in these cartridges, we recommend replacing the wiper blade each cycle. Lightly coat the new blade with Kynar drum padding powder. Replace the wiper blade in the cartridge.

    NOTE: We do not recommend using zinc sterate with this cartridge; it will stick to the PCR and cause small white voids in the printed characters.

    10. Open the drum cover fully and remove the metal arm. Although it is fairly easy to remove the entire cover, it is not necessary. Either hold the cover open with your hand, or use a small piece of tape.

    Figure 12

    11. Remove the two screws that hold the gear housing cover on the right side of the cartridge. There is a plastic tab on the top that must be pressed down to release the cover. Be very careful not to damage any of the pins on this cover when it is being removed. Note that they are similar to the 4000, but again slightly different. They are attached to the cover, and can only be removed if you press the tabs in.

    Figure 13

    Figure 14

    12. To remove the magnetic roller, carefully lift the roller up and out of the cartridge. Be very careful not to damage the wire contact at the opposite end of the roller. It is not necessary to remove the opposite end cap.

    Figure 15

    13. Remove the doctor blade by removing the two screws and lifting it straight up. When removing this blade, be very careful not to break the alignment pins. These pins keep the doctor blade at the proper distance from the magnetic roller. Don't damage or lose the clear plastic spacers, or the print quality will suffer.

    Figure 16

    Figure 17

    14. Vacuum the toner supply chamber thoroughly.

    15. Fill the hopper with the appropriate amount of toner.

    Figure 18

    16. Clean the small end cap contacts with a cotton swab and alcohol.

    Figure 19

    17. Inspect the end caps on the magnetic roller sleeve to make sure they are not cracked. If they are cracked, they will tear the coating off of the OPC drum.

    NOTE: these cartridges do not use magnetic roller felts. Instead, small curved magnets contain any toner that may try to migrate past the mag roller.

    18. To change the magnetic roller sleeve, press the magnet from the gear side until the white bushing pops out from the opposite side. Slide the stationary magnet out from the old sleeve and into the new sleeve.

    Figure 20

    19. Place the two magnetic roller end caps (black on the contact side, green on the gear side), bushing and gear on the new sleeve. Clean the contact spring of the magnetic roller, and the contact-side end cap with the alcohol. Coat the contact side end cap with a small amount of conductive grease.

    Install the new doctor blade (don't forget to take the plastic spacers off the old blade and put them on the new), magnetic roller assembly, assembly end caps and gears. Spin the roller a few times to make sure all components are aligned properly.

    NOTE: The only way to seal this cartridge is to split or replace the hopper. This an issue with this cartridge because of the contacts that are now in the way of a splitter. Splitter manufacturers are actively working on this problem and may have something ready at the time of this publication.

    Figure 21

    Figure 22

    20. At least by going to a round fill plug, those of you who use filling machines will have an easier time of it.

    Figure 23

    Figure 24

    21. Coat the OPC Drum with the Kynar, and replace the OPC Drum, and Axle Pin. Do not install the screws yet.

    Manually spin the OPC drum in the proper direction (toward the edge of the wiper blade) to make sure everything is properly lubricated. If the drum binds, remove it and recoat the wiper blade and drum with Kynar.
    22. Remove the OPC Drum, and place aside.

    23. Clean the PCR silver contact ends along with the U-shaped contacts with the isopropyl alcohol. These are electrical contacts and must be clean in order for the cartridge to print correctly. Be very careful not to get the alcohol on the rubber part of the PCR as this will remove the conductive coating and ruin the PCR.

    24. Clean and replace the PCR.

    WARNING: Do not clean the PCR with alcohol as this will remove the conductive coating on the roller. IF the PCR is an aftermarket, follow the cleaning methods recommended by the manufacturer. If the PCR is an OEM, we recommended that it be cleaned with a PCR cleaner.

    25. Re-install the OPC drum, drum axle pin, drum end caps and screws. This order for reassembly helps prevent the PCR from being contaminated with the Kynar padding powder. Make sure you align the small plastic pin in the center on the oblong slot on the drum axle pin. If this is not set right, banding will occur.

    Figure 25

    26. Place the two halves together and insert the two silver pins.
    Although the HP 4100 machines look similar to the 4000, there are differences. The following information includes basic Hewlett-Packard printer information as well as items specific to the 4100 series.


    Printer Maintenance

    Transfer Charge Roller: In the base of the printer, there is the transfer charge roller. This foam roller must be kept clean. Be very careful not to touch this roller with any part of your skin. The oils naturally present in your skin, paper dust and toner dust can contaminate the roller, causing light prints and/or small white voids in the text.

    Anti-Static Teeth: Located just behind the transfer charge roller assembly is the anti-static teeth blade. This blade dissipates the static charge applied by the transfer charge roller from the paper. This helps prevent the paper from sticking to any of the rollers and causing a paper jam.

    Fuser Assembly: Designed to be self-cleaning, the HP 4100 does not use a felt wand. There seems to be a little-known fact that the newer fusers (those that do not use a felt wand), have a "fuser bias" signal placed on the upper roller/sleeve. This signal helps keep the roller/sleeve clean by repelling the toner off the roller/sleeve and onto the page.

    Component Replacement: The fuser assembly, transfer charge roller, separation pad and the paper feed rollers are designed to be replaced every 200,000 pages.

    Running Test Prints

    To run a test print, verify that the printer is still offline, and press the MENU button one time. The INFORMATION MENU should appear on the display. At this point you have a few options as to which test print to select.

    Press the ITEM button one time to display the MENU MAP. This is a text and graphic printout that lists all of the menu options. We recommending using this page for testing the cartridge.

    Press the ITEM button two times to display the PRINT CONFIGURATION. This text page lists the current configuration.

    Press the ITEM button three times to display the PRINT PCL FONT LIST. This is also a text page.

    Press the ITEM button four times to display the PRINT PS FONT LIST. This is also a text page of all the Postscript fonts.

    Press the ITEM button five times to print the Event Log.

    Press the ITEM button six times to show the Event Log.

    Press the ITEM button seven times to print the supplies status page. once new chips are available, this page should be printed to make sure that the chip is working correctly.

    Press the ITEM button eight times to print the paper path test. Once you have decided which test print you want, press the SELECT button one time, and the printer will print the test page(s) you selected.

    As stated above, we recommend printing the Menu Map page and the Supplies Status page. This combination will print both text and graphics as well as tell you the chip status.

    Printer Cleaning Page

    According to HP, the printer cleaning page should be run every time a cartridge is changed or when the print quality deteriorates. The 4100 printer can also run the cleaning page automatically at a page count that you set.

    To run the page manually: press the MENU button four times until PRINT QUALITY MENU appears on the display. Press the ITEM button six times until CREATE CLEANING PAGE appears. Press the SELECT button. To run the cleaning page through a machine, press the ITEM button six times until PROCESS CLEANING PAGE appears. Follow the instructions listed on the cleaning page you have already printed.

    To run the page automatically: press the menu button four times until PRINT QUALITY MENU appears on the display. Press the ITEM button five times until AUTO CLEANING PAGE appears. Press the VALUE+ button until =ON appears, then press the SELECT button. Press the ITEM button one time so that FREQUENCY= appears. Press the VALUE+ button to select the frequency, then press SELECT. Press the ITEM button until CLEANING PAGE SIZE=LETTER, followed by the VALUE+ button to select. The cleaning page will now run at the frequency you selected. The auto cleaning process takes about 2.5 minutes to process. The frequency can be set at every 1,000, 2,000, 5,000, 10,000, or 20,000 pages.

    Diagram 1

    Diagram 2

    Hewlett-Packard LaserJet 4100 Cartridge Printing Theory

    Diagrams 1 and 2 offer a visual of HP 4100 cartridge printing theory, which is basically the same as in the 4000 machines. The following describes the printing process from start to finish in order of the events.

    Before the printing process begins, the printer checks proper cartridge installation. This is done by placing a signal on the PCR. A feedback signal is returned to the printer telling it that a cartridge is present. Chip detection and toner low sensing all took place when the printer was turned on. After all this, actual printing can start.

    The cartridge printing process is best explained as a series of steps or stages.

    Stage 1: Uniform Charging

    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.

    Stage 2: Latent Image

    In the second stage (which takes place in what is called the imaging section), the laser beam will discharge the DC voltage to ground wherever it strikes the OPC's surface, thus leaving a latent electrostatic image on the drum. The OPC drum's circumference is 3.66 inches, or approximately one-third of a page, and therefore makes three revolutions for each 11-inch printed page.

    Stage 3: Development

    In the third stage, the toner image is developed on the drum by the developing section (or supply chamber), which contains the toner particles.

    The toner is held to the magnetic roller sleeve by the stationary magnet inside the sleeve and a DC bias voltage supplied by the high voltage power supply. This DC bias voltage is controlled by the printer's density setting, and causes either more or less toner to be attracted to the drum, which either increases or decreases print density. Both the primary charge roller and magnetic roller DC bias voltages are controlled by the printer's density setting.

    The amount of toner on the magnetic roller sleeve is controlled by the rubber doctor blade, which uses pressure to keep the amount of toner on the magnetic roller sleeve constant. This blade also causes a static charge to build up on the toner, which helps keep the coating of toner even and allows easy transfer to the OPC drum.

    At the same time an AC signal is also placed on the magnetic roller sleeve. This signal decreases the attraction of the toner to the magnetic roller sleeve and increases the repelling action of toner from the areas of the drum that were not exposed to the laser beam. This AC potential improves the density and contrast of the toner on the printed page.

    As the laser-exposed areas of the OPC drum approach the magnetic roller, the toner particles are attracted to the drum's surface due to the opposite voltage potentials of the toner and the laser-exposed surface of the OPC drum.

    As the transfer charge roller moves the paper, it applies a positive charge on the back of the paper. This image on the OPC drum is then transferred to the paper as it passes under the drum. The positive charge on the paper causes the negatively charged toner on the drum's surface to be attracted to the page.

    The small diameter of the drum, combined with the stiffness of the paper, causes the paper to peel away from the drum. The static charge eliminator weakens the attractive forces between the negatively charged drum surface and the positively charged paper. Without this help, thin paper may wrap itself around the drum.

    After development, the paper travels to the fuser assembly, which is comprised of the upper and lower fuser rollers. The lower rubber roller presses the page into the upper roller, which then melts the toner into the paper. The upper roller or sleeve consists of a ceramic heating element with a Teflon sleeve. The fuser heat can be controlled through the printer menu as well as the ambient room temperature sensor. The fuser temperature adjusts automatically to extreme high and low temperatures.

    Stage 4: Cleaning

    The next stage is where the OPC drum is cleaned. On average, approximately 95 percent of the toner transfers to the paper during the print cycle. The remaining 5 percent 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 is complete, the primary charge roller places an AC voltage across the drum surface to erase any residual charges left on the drum surface. At the same time, the PCR applies negative DC bias voltage the OPC drum to condition it and prepare for the print cycle again.

    All during the printing process, the engine controller board monitors the actual amount of toner used per page to calculate the estimated life left in the toner cartridge. This is shown on the supplies status page.

    This completes the recharging process!

    The technical staff of Faroudja Toner can be reached at (650)-593-3862 or by email at .








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