grainy image on checks

[cocanaz]

hi, i have a laser jet pro 4100dn and i am on my 2nd MICR toner. bought from Troy. i have printed out a check and some places are still grainy. then i run my finger over the check area and it continues to smudge. i print on regular paper with MICR toner and it doesn't smudge. so do i conclude that the check stock is the issue? i am at my wits end and this has been an issue for me for over 2 months. i cannot keep doing this and having vendor checks not be able to be deposited. thank you.

[MysteriousMe]

Welcome to HP Support Community, @cocanaz 

Thank you for posting your query, I will be glad to help you.

MICR toner is magnetic and slightly wax-based. For it to fuse correctly and not smudge, the paper needs to be:

Laser-printer compatible (high heat tolerant coating)

Non-glossy / not over-treated

At the correct moisture and surface texture for toner bonding

Many check stocks have coatings for inkjet or security treatments that prevent proper fuser adhesion, which leads to:

Grainy appearance

Easy smudging

Toner not fusing into the fibers

Before we 100% conclude, test these on your check paper:

 1. Increase fuser heat / change media setting

On the printer or driver, set paper type to:

Heavyweight

Cardstock

or Bond Paper
(This forces higher fuser temperature for stronger toner fuse)

2. Print a solid black patch on the check stock

Let it cool 10 sec → rub it with your finger

If it still smudges → paper is the issue

If it doesn’t smudge → previous paper setting wasn’t heating enough

3. Check paper specifications

Confirm that the check stock package supports:
laser printer
and MICR laser printing specifically — not just security printing.

Additional checks on the printer side (just to eliminate any doubt):

The 4100dn model uses the fusing unit:
laser fuser unit
If fuser were failing, you would see smudging on all paper, which you are not — so hardware failure is unlikely.

Ensure toner meets:
MICR
standards for check printing.

The supplier you purchased from appears to be:
TROY Group, Inc.
which is reputable, but even valid MICR toner can smudge if the media is not laser-compatible.

Final answer:

🧾 Yes, you can reasonably conclude the check stock is the root cause, especially if tests above still smudge.

What to do next:

Change media type to heavier heat mode (Heavy/Bond/Cardstock)

Test black patch smear

If still smudging → switch to true laser MICR check paper such as:

Blank laser check paper designed for MICR (no glossy coating)

24–28 lb high-heat bond with MICR compatibility

If vendor checks must be fault-free, ask your paper supplier for:
laser-rated MICR check stock replacement

I hope this helps.

Take care and have a good day.