HP Color LaserJet 1600, 2600, 2605, CM1015, CM1017 Electrostatic Transfer Belt.

HP Color Laserjet 2605 Belt

Colour laser printers commonly build the page image on an Electrostatic Belt of some kind. In the CLJ 1600, 2600, 2605 and the CM1015 / CM1017 have a belt mounted in the cartridge door of the printer - its the big silver-black object.

The Electrostatic Transfer Belt or ETB in these printers transports paper past the colour print cartridges. Transfer rollers behind the belt provide the transfer voltages to pull toner-powder onto the paper.

The belt is also used in printer calibration. There is a density and registration sensor at the top rear of the belt. When the machine calibrates it prints squares and patterns of toner direct to the belt and then rotates it under the sensor where a couple of opto-detectors sense reflected light.

HP Color Laserjet 2605 Mechanism

The belt is cleaned as it goes back over the cartridges, surplus toner is removed by manipulating the voltages on the transfer rollers and drums so that toner on the belt goes back to the drums and into the waste area inside the cartridge.

Note that the belt is fragile. Never place anything on it (such as toner cartridges) and avoid touching it.

In operation, the transfer belt often does look dusty with toner and whilst this isn't good - it suggests leak-prone refilled toners are in use - the belt and cartridges can cope with some stray toner, it doesn't usually interfere with the working of the machine.

Cleaning the ETB

The printer has an ETB cleaning mode. (see the user guide)

Don't touch the belt, it is an electrostatic device and its working depends on the surface having the right static-electric properties. A belt can't cope with finger-marks or particles larger than toner. However after some time in use the ETB may become quite heavily contaminated with stray toner and ordinary dust - and then colours will become uneven. If the belt has to be cleaned use:

  • A soft, dry, clean brush - such as a small paintbrush. It must be clean and not likely to shed bristles.
  • A fresh, clean, lint-free cloth. If there are finger marks or other contaminants on it dampen the cloth with water or isopropyl alcohol to remove them. Do not use detergents. Never use any ammonia based cleaners - they will damage both the belt and the cartridge drums so the printer will be a write-off.
  • A professional toner vacuum cleaner with a filter rated for 0.3 microns. Toner used in these printers has grains about 5 microns across but there is a small proportion with much finer grain size. An ordinary vacuum cleaner will blow microscopic particles all over the room.

Unless it is very heavily contaminated by an obviously defective toner cartridge the belt surface itself usually should not need to be cleaned - the machine is capable of doing the job itself. The metal contact points along the sides do attract toner which might then cause a poor contact so they may need to be cleaned. Use a toner-vac or cotton bud to get into the recesses and isopropyl alcohol to get at any greasy contamination.

It may be a bit inconvenient having a large, and rather fragile device mounted in the door of the printer but it is a characteristic of this design. It would not have been easy to provide any protective covering.

HP Color Laserjet 2600 Series Belt

ETBs

There are several printers using the same Canon LBP-5000 engine. The belts are all pretty similar, the notable difference being that for the CLJ 2605 which has part of the duplex paper path down it's back face.

HP Color Laserjet 2605 Belt for non-duplex models

RM1-1885 ETB for CLJ 1600, 2600N, CM1015, CM1017 - RM1-1885-020CN

Fits the

  • Color Laserjet 1600
  • Color Laserjet 2600N
  • Color Laserjet CM1015
  • Color LaserJet CM1017

RM1-1891 ETB for CLJ 2605 Simplex version only - RM1-1891-000CNFits the

  • Color Laserjet 2605 Simplex printer only.

HP Color Laserjet 2605 Belt with Duplex

RM1-1892 ETB for CLJ 2605 Duplex version only - RM1-1892-000CNFits the

  • Color Laserjet 2605 Duplex (double sided print) model only.

Note the duplex feed motor on the back of the belt.


HP Color Laserjet 2600 Series Main Components

Before Starting Work

The ETB in the CLJ 2600 series printers is not easy to change. The next- higher machine in the series is the CLJ-2700 /3000 / 3600 and its belt just unplugs from the front and another slides into place. No such luck here. The belt has two screws at the front bottom of the printer holding it in place and then there is a wiring harness on the right side going into the electronics. To get at these parts the sides have to be removed.

warning

Before work first turn off and unplug the printer. Removing the plastic panels exposes voltages which could be fatal. The right side of the printer largely comprises the High Voltage Power Supply (HVPS) which has about 14 circuits delivering up to 7,000 Volts for the various electrostatic transfer mechanisms. In normal use the lid switch turns these off when the printer is open, but if you are working on the printer and the board itself is exposed so are some high voltages. There is no need to have power to the printer whilst working on the ETB. There are no fine adjustments to be made with power on. Make sure power is off.

warning

Also take care to protect the printer electronics against electrostatic discharge from yourself. People wearing artificial fibres commonly make charges of several thousand volts that can damage electronic circuits if they discharge in the wrong place (they are at lower current than the fatal voltages present in the printer, but can damage chips). Wear an anti-static strap or - if non is available, discharge any static onto a grounded surface such as a metal radiator


HP Recommend the following tools:

  • Philips No 2 screwdriver with a magnetised shaft at least 150mm (6 inches) long. (They dislike use of Pozidrive tips)
  • A small flat blade screwdriver (often called a terminal screwdriver) .
  • Needle -nose pliers
  • An Anti-Static Strap

ETB Removal and Replacement Procedure

screw locations - right

Pull the paper cassette right out of the machine, it obstructs the side panels.

tab locations - left

Remove the delivery tray from the top of the machine. HP don't give these instructions but the parts are quite fragile and best put to one side.

Remove two screws from the right side cover.


screw locations - left

Remove one screw from the left side cover.

tab locations - left

The screw is in the hand-grip at the bottom of the printer.


screw locations - right

Open the front door. Be careful not to touch the ETB surfaces (if you are changing it that may not matter any more - but is it re-useable ?).

recycle

At the moment we don't have any recommendations on recycling the ETB but it's clearly something that ought to be possible.


right side tab locations - right

Remove the right side by twisting the front edge of the cover outward, there is a tab about halfway up that needs to release. The side panel then pivots away from the front as though there were hinges at the back. It may need moderate force as various little protrusions hold it under the top cover. It can be done without removing the top.

If you intend to replace the fuser, or just don't like wrenching at plastic parts it may be easier to remove the top cover as well.


left side tab location

Remove the left cover, there is a tab on the lower front corner just at the level of the tray that needs to be released.

top screw location

The cover pivots round from the front.


link lever location

Squeeze the white plastic left hand side door link-lever to release the ETB from the door.


catch screw location

Remove the screw from the plastic catch on the upper right side that holds the ETB to the cover


ETB_re-closed

Close the ETB, but now leave the front door open - the catch will hang lose.

The ETB needs to be closed when the hinge-screws are removed or its weight will fall fully on the hinge screws as they are removed.


Wire Harness Cover

Remove the cable cover from the left side front of the printer, exposing the ETB cable harness.

Wire Harness Cover 2
Wire Harness

Remove the cable connectors from the ETB to the chassis and undo the grounding screw

Right hand HVPS

Pull out the white HT wire from it's connector


ETB Left Hinge Screw

Remove the ETB hinge screws on both sides

ETB Right Hinge Screw
ETB released

Remove the hinge cams on both sides, needle nosed pliers will help.

ETB out

The old ETB should now lift free


ETB Reinstallation

ETB labelled

As with many things installing a new part is essentially just a matter of reversing the actions needed to remove the old part.

Align the new ETB with its screw holes at the base, taking care to avoid contact with the belt itself. Handle it by the sides. If you do accidentally touch the surface of the belt use a slightly moistened lint free cloth to remove any mark.

On the right side first, put in the hinge cam and its securing screw

Work back through the steps, remembering to plug the connectors back into the holes they came from. Reassemble the machine before plugging it back in and testing it.

The full procedure for both ETB and Fuser can be found in the service manual. Use Google to search for Q7821-90930 or buy a manual from one of the websites specialising in such things.



Copyright Graham Huskinson and Mindmachine Associates Ltd 2009-2012. Mono Pictures from the HPs Service Manual