Topics: Freejet Maintenance

Cleaning the Freejet Encoder Wheel

About the Encoder Wheel

The encoder wheel is a semi-transparent disc that rotates in sync with the movement of gears that drive the gantry of Freejet printers forward and backward.

Tiny lines are etched around the outer 1/4″ or so of the wheel and these lines are read by a sensor and communicated to the printer’s control electronics to monitor and control the gantry’s position, relative to its rear or home position.

The encoder wheel is positioned far enough away from the print head carriage’s range of travel that it is unlikely to be affected by ink overspray and is normally protected from settling environmental debris by the gantry cover. Since it is largely isolated from debris in most environments, it generally only needs to be cleaned if you note problems with the vertical registration of prints — in other words, only if you note distortions in the vertical (top to bottom) dimension of prints.

Cleaning the Encoder Wheel

The below video demonstrates how to clean the encoder wheel in the Freejet 330-series of DTG printers.

Be careful not to bend or crack the encoder wheel while cleaning it. Gently press your lint-free cloth against the wheel, just enough to clean off any loose dust or debris on the surface. Only the outer edge with the notched lines is cleaned.

Never use tools that could scratch the surface of the encoder wheel, since any scratches may be read by the sensor as false information about the gantry position, requiring that the encoder wheel be replaced.
An alternative “no touch” technique to cleaning the encoder wheel is to spray it with a can of compressed air to remove any loose debris resting on its surface.

Monthly Maintenance: Freejet 330-series (video)

There are two maintenance tasks that should generally be performed on a monthly schedule: carriage bar cleaning & lubrication and resetting the waste ink pad counter.

Cleaning & lubricating the carriage bar

This video demonstrates and explains how to properly clean and lubricate the carriage bar.

Remember to use only a lint-free cloth or paper towel for the cleaning procedure, and only OmniPrint’s blue Freejet Grease for lubricating the carriage bar. Use of any other lubricant may damage the carriage, requiring that it be replaced. Damage due to improper maintenance is not covered by the warranty.

Resetting the waste ink pad counter

Resetting the waste ink pad counter is done 100% in software. The details on performing that aspect of the monthly maintenance are available here.

Maintenance Log Sheets

Performing the recommended maintenance is the most important factor in maximizing your equipment’s service life and consistently getting high-quality prints.

We recommend using the daily, weekly, and periodic maintenance log sheets for your printer and pretreatment machine (PDF download links below), to help you and your staff track and manage your equipment maintenance schedules.

Consistently performing the recommended steps at the beginning and end of each printing day will go far to prevent interruption of your production work that could otherwise occur due to insufficient maintenance.

Staying on top of the daily, weekly, and other periodic preventative maintenance also helps to maximize the service life of the equipment and protect your warranty.

Installing Freejet Support Kit Parts

The Freejet Support Kit consists of the following items:

  • Pump
  • Pump Soak Pad
  • Waste Ink Pad (for spit tray)
  • Dampers (8)
  • FreeJet Clips (8)
  • Ink Tubes (8)
  • O-rings (8)

…all of which are consumable parts for the Freejet. Most of these parts will need to be replaced on a regular basis — some within the first year. Having a Support Kit on-hand will minimize downtime, allowing you to usually get your printer back up in minutes, rather than waiting for the parts to be ordered and delivered. As an added benefit, the Support Kit provides $700 worth of parts for only $575 — a discount of almost 20%!

Order a Freejet Support Kit

This article will discuss each part in the Support Kit, and serve as a brief How-To Guide for replacing those parts. We recommend reading this entire article before doing any disassembly. You may also wish to review the following video before replacing dampers.

Damper Replacement Video

Dampers, Ink Tubes, Clips, and O-Rings

Tools needed: small or medium needle nose pliers, #2 Phillips head screwdriver

On the top of the print head, locate the staircase-shaped metal plate. This is the Damper Panel.

Two screws hold the damper panel in place.

Use your #2 Phillips head screwdriver to remove the two screws holding the damper panel in place. Slide the damper panel off, then set it and the screws carefully aside.

Damper Removal

It is important to take care to avoid ink spills inside the print head carriage, so note that the dampers have a disc-shaped valve that will release ink from the bottom of the damper if the valve is squeezed from the sides of the diaphragm.

If any ink should spill inside the Print Head Carriage, clean it out immediately. If allowed to remain in the carriage, the ink can drain onto electronics and cause severe and costly damage to the machine.

Using your needle nose pliers, grasp the brass nut at the front of each damper and gently lift straight up to pull the dampers out of their positions. It may be helpful to slightly rock the damper from front to back to release its seal on the top of the print head nozzles, but avoid rocking side to side.

Only grasp dampers by the brass nut at the front of the damper or by the front and rear outer edge of the rigid frame (not by the wide, thin sides) to avoid accidentally puncturing the thin plastic diaphragm.

Demonstration of proper damper handling, using only the front & back of its frame or the brass nut.

Once dampers have been lifted up, allow them to hang in front of the Print Carriage, for now. Ink may drip from the dampers so it’s recommended to put a scrap shirt, shop rag, or paper towel directly under the dampers.

Unscrew the nut from each of the dampers and slide it up the ink tube a bit to expose the o-ring (to ensure that it doesn’t fall off), then pull the end of the ink tube off of the damper.

Evaluation & Replacement of Ink Tubes, Clips, and O-Rings

At this point we want to evaluate the condition of the printer’s ink tubes, clips, and o-ring. If any of those parts are showing signs of significant wear then this would be a great time to replace them.

Here’s what to look for:

  • Ink tubes – Replace when out of round with severe crimping which may restrict ink flow
  • Clips – Replace with any sign of brittleness or cracking
  • O-rings – Replace if no longer supple or with any sign of cracking, brittleness, or distortion of perfectly round shape

Regardless of their condition, some customers prefer to proactively replace these parts on a regular schedule, all at once, before they impact print quality to minimize future production interruptions.

If replacing only the damper, skip to that section below.

If you are replacing the ink tube, clip, or o-ring, first slide (or roll) the o-ring off of the ink tube, then slide off the brass nut. If replacing the clip, slide that off next.

If you are replacing the ink tube itself, observe where this short ink tube connects to the main ink line as an overlapping, air-tight sleeve.

It is best to push the ink tube off of the main ink line using a thumbnail or a thin, stiff tool (with no sharp edge.) You can also try rotating the ink tube while pulling it off of the main ink line, though pulling may cause the ink tube to stretch and become tighter.

Be careful, and place a drop cloth underneath the ink lines and tubes as you do this, or you’ll risk spilling in the Print Head Carriage!

If replacing more than one ink tube, complete each ink tube (plus clip and o-ring reinstallation or replacement, as needed) before moving on to the next set. Doing them one at a time minimizes the risk posed by spills.

The order of installation for this set of parts is:

  1. Ink tube
  2. Clip
  3. Brass nut (with open end facing the end of the ink tube
  4. O-ring

Damper Replacement

To attach your new damper, push the open end of the ink tube onto the ink intake port on the front of the damper, and screw the brass nut in place to secure it, making sure the o-ring is on the ink tube and inside the brass nut’s opening. Tighten the nut so it is snug, but be careful to make it only hand tight since the damper’s plastic threads can be easily stripped if overtightened.

After all desired parts have been swapped, gently grasp the first damper by the brass nut, and position it so the open, circular port on the bottom of the damper is pointing straight-down over its matched nozzle post on the print head.

Print head damper posts, which dampers are mounted onto.

Lower the damper straight down and into position, ensuring that the plastic “U-shaped” alignment slot at the front of the damper wraps around the metal tab of the Damper Alignment Bracket.

A U-shaped slot at the front of each damper is aligned with the upright tab on the alignment plate.

Press straight down to the top of the damper, near its rear (immediately above the print head’s associated damper post) to secure it into position. You will feel a slight bit of resistance as the damper mates to the print head post, followed by firm resistance once the damper is fully seated onto the post.

Repeat for any other dampers, ink tubes, o-rings, and/or clips to be replaced.

When complete, with all 8 dampers evenly spaced and at equal height, replace the damper panel and screw it back into place.

Waste Ink Pad

The Waste Ink Pad is located inside the Waste Ink Spit Tray, inside the carriage assembly, at the far left end — opposite the print head carriage’s home position over the pump.

Waste ink tank or spit tray

The Waste Ink Tank (or “Spit Tray”) contains the Waste Ink Pad

Using your syringe, suction out the waste ink inside the Waste Ink Pad compartment, and dispose of it with the rest of your waste ink. Once the ink is removed, use a pair of needle nose pliers to pull out the old, soaked pad. Insert the new pad in its place.

Cleaning out the waste ink reservoir and replacing the soak pads

Pump and Pump Soak Pad

The Pump has a more involved replacement procedure which should only be done with the live assistance of an OmniPrint Technician, at least while the printer is under warranty. Also, replacing the pump sometimes requires access to a circuit board that can be damaged if mishandled.

Please contact our Technical Support team to request assistance if you believe the pump needs to be replaced, to avoid potentially damaging your printer and voiding its warranty.

During the pump replacement process, we also replace the Pump Soak Pad, which is placed underneath the pump.