This is the question every first-time check printer asks, and the honest answer has two halves: what the standard says, and what actually happens.
What the standard says
The specification calls for the MICR line to be printed in magnetic ink so it produces a readable magnetic signal. MICR toner is ordinary toner with iron oxide added. Cartridges are made for common laser printer models and cost noticeably more than standard cartridges.
What actually happens
Cheque processing equipment has read both magnetically and optically for many years. A check printed with standard toner usually carries a perfectly legible MICR line optically, and in practice a great many low-volume checks printed on home and small-office printers clear without incident.
When a line cannot be read at all, the item is not rejected outright — it drops out of automated processing into an exception queue and is keyed by hand. That costs the bank money, which is why some banks charge a fee for unreadable items and why high-volume printing is a different conversation from occasional printing.
Deciding by volume
| Volume | Recommendation |
|---|---|
| A few checks a month | Standard toner is generally fine; ask your bank |
| Tens of checks a month | Consider MICR toner; the per-check cost is small at that volume |
| Hundreds a month | Use MICR toner and a laser printer dedicated to checks |
| Any volume, after a bank complaint | Use MICR toner |
Inkjet printers
Magnetic ink cartridges for consumer inkjets are not generally available. An inkjet can print a perfectly good check that is read optically, but it cannot produce a magnetically readable line. If your bank insists on magnetic readability, you need a laser printer.
Print quality matters as much as magnetism
Even with the right toner, a MICR line fails if the printing is poor. The practical checklist:
- No draft or economy mode. Light toner reads badly either way.
- Correct fuser setting for the paper weight, so toner bonds instead of flaking.
- No scaling. See what is a MICR line.
- Clean rollers. Streaks across the band cause misreads.
- Let the sheet cool before stacking, so the line does not offset onto the next check.
Ask the bank, once
One phone call settles it for your situation: ask whether they have a requirement for magnetic ink on checks drawn on your account, and whether they charge for items that require manual processing. Bank policy varies, and it is the only authority that matters for your account.