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

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 printer’s life and consistently getting high-quality prints.

We recommend using the daily, weekly, and periodic maintenance log sheets for your printer (PDF download links below), to help you and your staff keep your Freejet in top condition.

Doing a few maintenance steps at the end of each printing day, along with a very few other weekly and periodic routines will go far to mitigate any potential interruption to your production work that could occur due to insufficient maintenance. You will also be maximizing the service life of the pump and print head by staying on top of routine maintenance.

Grinding Noise Solutions

A grinding sound coming from your printer means that routine maintenance needs to be performed. We’ll cover some details about why this can happen and what type of maintenance, but first let’s run through a brief explanation of what causes the grinding sound.

What is Making that Sound?

A rubber drive belt connects the carriage drive motor to the print head carriage. This belt is firmly attached to the print head carriage, so if the motor is turning but the carriage can’t move, then the drive belt will slip on the motor’s cog. The grinding is the sound of the drive belt slipping across the motor’s cog.

Read on to see two reasons why the carriage may not move properly when the motor is engaged and how to resolve them both.

Ink Build-Up In the Pump

Ink build-up in the pump is the most common cause of grinding, due to the carriage being stuck in its docked position. Fortunately, it is easy to prevent by diligently cleaning the capping station and wiper blade areas of the pump, which is part of the daily maintenance routine — that is, the maintenance that should always be performed at the conclusion of any printing day.

How is it that ink in the pump can keep the carriage from moving?

Before directly answering that question, it’s helpful to understand that the pump does more than the obvious work of pumping. It’s set of gears and the related electronics also control rotation of the wiper blade, raising and lowering the capping station, as well as raising and lowering the carriage lock arm.

Bottom view of the pump mechanism, exposing gears for wiper blade & carriage lock arm movement

The carriage lock arm is in the left-rear section of the pump (when viewed from the front of the gantry.) When raised, the lock arm protrudes into a slot on the carriage assembly, locking it into position and preventing movement of the carriage until the lock arm is lowered.

Top of pump, viewed from the rear

Now, with the understanding that the pump includes a set of gears and other moving parts (the wiper blade, capping station, and carriage lock arm), we can understand that it’s not the ink that flows through the pump when priming or running head cleans that can lead to the grinding sound. Instead, it’s ink that can gradually drain down from the wiper blade area and down into the gears inside the pump.

This is one reason why the daily maintenance of the wiper blade and capping station areas are so important — to prevent the long-term drainage of ink down into the gears that control the movement of the carriage lock arm.

If you hear the grinding sound, do a thorough cleaning of the wiper blade and capping station area (see the below video for details), then reset the printer from its main power switch in the rear. If that doesn’t resolve the problem, proceed with cleaning the encoder strip.

A Dirty or Damaged Encoder Strip

The encoder strip provides a sensor on the printer’s carriage with necessary guideposts for keeping track of its horizontal position. These guideposts are in the form of thousands of tiny vertical lines running along the full width of the carriage, from left to right.

The encoder strip appears to be grey from a distance

Close up view of the encoder strip

A closer view of the encoder strip reveals that it’s transparent plastic with thousands of vertical lines

If the encoder strip becomes dirty then the printer may not be able to gauge its position accurately, and this can also result in the carriage belt grinding due to continuing to drive the carriage to the right after it has already reached its home position.

Cleaning the encoder strip is part of the routine weekly maintenance for Freejet 330-series printers, so your User Manual has detailed instructions on the procedure, beginning on page 31. (See links to the Freejet 330-series manuals below.) After thoroughly cleaning the encoder strip, turn the printer’s main power off for a few seconds from the rear switch, then back on.

If the grinding occurs again very shortly after performing the pump and encoder strip maintenance tasks referenced above, please contact Technical Support for further help.

How To Reset the Waste Ink Pad Counter

The Waste Ink Pad Counter and Why we Reset It

You may have noticed that the Freejet 330-series occasionally jets very small amounts of ink into a small, chrome-plated tank (or spit tray) at the far left end of the carriage assembly. Ink accumulates in this tank over time so the printer will periodically warn us that the ink level in this waste tank should be checked and emptied to avoid overflowing, and the absorbent pad at the bottom of the tank replaced, as needed.

Waste ink tank (“spit tray”)

That warning comes in the form of the ‘Error’ and ‘Ink’ lights on the control pad flashing — blinking in an alternating pattern. Once this has occurred the printer will no longer accept print jobs until we acknowledge and clear the error, using a software utility. But there’s no need for that to happen.

Rather than wait for this to happen, we proactively check the waste ink tank level visually to avoid overfilling, and we use a software utility called the Adjustment Program to reset the counter which triggers the error condition, as part of our routine monthly maintenance. By doing so, we avoid ever having a print job interrupted by that error condition.

Here’s how…

Resetting the Waste Ink Pad Counter

If you don’t already have the Adjustment Program on the PC connected to your Freejet printer, get it here.
The Adjustment Program should be used only as directed below. Any other use without the direct guidance of OmniPrint staff is strongly discouraged and may cause problems that would not be covered by the warranty.
  1. Use Windows File Explorer to navigate to where you installed the Adjustment Program, then double-click on the AdjProg program’s icon to launch the Adjustment Program.
    Windows File Explorer with AdjProg.exe selected
  2. Click on the ‘Particular adjustment mode’ button.
    Adjustment Program top level window
  3. In the pop-up window, confirm that the Port selection is set to ‘Auto selection’, then click ‘OK’.
    Adjustment Program Port Selection
  4. When the Adjustment Program window appears, scroll down to the ‘Maintenance’ section and select ‘Waste ink pad counter’, then click on the ‘OK’ button.
    Adjustment Program menu selection
  5. Click on the ‘Initialization’ button to reset the waste ink pad counter, then click ‘OK’ to close the informational window which pops up, then click ‘Finish’.
    Reset counter
  6. Click the ‘x’ in the upper-right corner of the Adjustment Program’s menu screen to close that window.
    Adjustment Program: closing the window
  7. Click on the Adjustment Program’s ‘Quit’ button to end the program.
  8. Turn the printer off from the rear power switch, wait 5 seconds, then turn it back on.

Congratulations! The waste ink pad counter has now been reset.


Wait… what about the waste ink pad?

The absorbent waste ink pad at the bottom of the waste ink tank should be replaced once it is thoroughly saturated. See our article about replacing consumable parts for details on how to replace the pad.

About Consumable Parts

Consumable parts are those parts that are expected to require replacement on a regular basis, as part of normal maintenance for optimal performance and reliable operation, not due to any manufacturing defect.

Probably the most familiar examples of consumable parts are tires and air & oil filters on a car. The fact that they have to be replaced periodically does not point to any type of flaw — it’s normal and expected.

damper

A damper for the Freejet 330-series DTG printers — a consumable part.

Some of our consumable parts are dampers, ink clips, ink tubes, o-rings, and pumps. Just like tires wear out, so do consumable parts on your printer. These types of consumable parts periodically need replacement due to normal wear.

Your warranty does cover any defects in parts or workmanship, and if a consumable part is deemed by OmniPrint staff to have been defective on a brand new printer it will be covered. We also provide a 1-year warranty on the print head against spontaneous clogging, while other DTG manufacturers typically treat print heads as consumable parts. Damage or clogging due to head strikes or lack of maintenance is not covered, however.

Installing Parts from the Support Kit

by A. Pelayo

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%!

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.

Head Strikes

One of the most damaging problems that can occur to your printer is a Head Strike, or a Head Rub. Avoiding this will not only extend your print head’s life, but will save you both time and expensive repairs.

What is a head strike?

A head strike is when the print head contacts, or strikes, a garment or platen.

Results of a head strike

If a head strike occurs, the print head may be damaged. If the head strike is on a pretreated garment it will likely clog nozzles and may permanently damage the print head.

How to avoid head strikes

Properly positioning the platen, mounting the garment, and setting the platen height so that the print head has sufficient clearance will ensure that you never experience a head strike.

What to do if you get a head strike

  1. Immediately lower the platen (‘Down’ button)
  2. Abort the print job (tap the ‘Feeding’ button)
  3. Prime all ink lines for a full pump cycle
    1. Monitor the waste ink bottle and interrupt priming to empty it, as needed
  4. Run two head cleans
  5. Print a nozzle check

If the nozzle check is good, continue printing to keep ink flowing through the nozzles, then wet cap in Super Nozzle Cleaner overnight when finished printing.

If a good nozzle check cannot be achieved by following the above steps, contact tech support to see if permanent damage can be avoided.

See pages 11-12 of your User Manual for details about positioning the platen and setting its height, and pages 14-15 for details about mounting garments onto the platen.