Why is my batch code coming out stretched or squashed?

Almost always the roller. It measures how far the machine has travelled, and the print is laid down against that measurement, so a roller that slips, sticks or has a flat spot distorts the print along its length. Clean it first — ink and dust build-up causes most of it. If cleaning does not fix it, the roller or its bearing has worn. If a new roller does not fix it either, look at the encoder next.

How often should a guide roller be replaced?

It is a wearing part and there is no useful interval, because it depends entirely on what you print on. Abrasive kraft board wears one far faster than smooth film. Treat it as a consumable, keep a spare, and change it when print geometry drifts rather than on a schedule.

Can I print without the roller fitted?

The machine may allow it, but you should not. Without the roller the machine has no measurement of travel, so print spacing depends entirely on the operator moving at a perfectly constant speed, which nobody does. The result is a code that is legible on some packs and not on others.

Handheld coder part

Guide roller for handheld batch coding printers

The wheel that rides the pack and measures how far the machine has travelled. Everything about print geometry depends on it turning cleanly and staying in contact.

Also known as: travel roller · measuring wheel · printer wheel · drive roller · contact roller

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Parts are sold against your machine, not against a picture. Send the model plate and a photograph of the part in place and we confirm the fit in writing before anything is dispatched.

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When this is the part that has failed

Print stretched or squashed along the length of the pack
Characters wavering or wandering as the machine moves
The roller feels notchy, stiff or has flat spots
Print quality good on a smooth pack, poor on a textured one

What it is

Function: Rides the pack and turns travel into a measurement the machine prints against
Wearing parts: The rolling surface and the bearing
Usual cause of failure: Ink and dust build-up, hardening with age, or a flat from being parked loaded
Consumable: Yes, in normal use — it is a wearing part, not a repair

Does it fit my machine?

Roller diameter and mount are specific to the machine body. Because a roller is cheap and it is the first thing to suspect for any geometry fault, it is worth keeping a spare regardless of whether one has failed yet.

Replacing it

1
Clean it before you condemn it
Most roller faults are ink and dust build-up. Wipe it with a lint-free cloth and the matching solvent and turn it by hand — it should spin freely with no catch.
2
Check for flats
Turn it slowly against a straight edge. A flat spot from being parked under load gives exactly the same wavering print as a worn bearing.
3
Remove the old roller
Usually a circlip, a grub screw or a single fastener. Keep the spacer that comes off with it; they are easy to lose and the roller sits wrong without one.
4
Fit the new one
Refit the spacer, seat the roller square, and check it turns freely with no side play before you tighten.
5
Print a long test message
Draw the machine across scrap at a steady speed. Stretch and bunching show up on a long message, not on a short one.

How we sell parts

Fit: Confirmed in writing against your model plate before dispatch
Invoice: GST invoice under HSN 8443 32 50 at 18%, against your GSTIN
Delivery: Anywhere in India, or free store pickup in Pune
Bulk: Quoted directly for resellers and service providers

Frequently asked questions

Why is my batch code coming out stretched or squashed?: Almost always the roller. It measures how far the machine has travelled, and the print is laid down against that measurement, so a roller that slips, sticks or has a flat spot distorts the print along its length. Clean it first — ink and dust build-up causes most of it. If cleaning does not fix it, the roller or its bearing has worn. If a new roller does not fix it either, look at the encoder next.
How often should a guide roller be replaced?: It is a wearing part and there is no useful interval, because it depends entirely on what you print on. Abrasive kraft board wears one far faster than smooth film. Treat it as a consumable, keep a spare, and change it when print geometry drifts rather than on a schedule.
Can I print without the roller fitted?: The machine may allow it, but you should not. Without the roller the machine has no measurement of travel, so print spacing depends entirely on the operator moving at a perfectly constant speed, which nobody does. The result is a code that is legible on some packs and not on others.

Related parts

Encoder

What turns the roller turning into the timing the print head fires on. It is the second half of the same job the roller starts, and the thing to look at once a new roller has not fixed a geometry fault.

Ink cartridge

The one part you will buy again and again, and the only one that decides your cost per thousand prints. On a thermal inkjet machine the print head is inside the cartridge, so this is a consumable rather than a repair.

Cleaning kit

The cheapest thing on this page and the one that saves the most money, because most cartridges thrown away as dead were blocked rather than empty.

Working across other brands and machine types too? Read the full spare parts guide, which covers continuous inkjet, thermal transfer and laser coders as well.