Quick check: symptom, cause, fix

Start at the top. The first three take seconds.

The fixes, step by step

1. Check print mode first

Most printing calculators can switch the printer off to save paper, and it is easy to do by accident. On a Sharp EL-1611P the display shows P in print mode and NP in non-print mode; on a Sharp EL-1801V the selector has an OFF position, a dot (display only), P (print) and P•IC (print with item count). Casio HR models have their own print/non-print setting described in the manual. If the display works and the tape does not move at all, this is the first thing to check.

2. Fresh batteries — and the right kind

Sharp's manual is explicit: when the batteries get weak, the display will work but not the printer. Casio lists slow printing as the sign. The printer draws far more power than the display, so the calculator can look fine and still not print. Use four new AA batteries of the same type — Casio advises against rechargeables. Some models want a reset afterwards; Sharp's EL-1611P manual, for example, says to press the RESET switch on the back. Don't leave dead batteries inside; they leak.

3. New machine? Remove the shipping tape

Casio ships its HR calculators with a strip of tape that holds the ink roller in place. The manual's first setup step is to take off the paper cutter and remove that tape. Left on, the paper feeds but nothing reaches it.

4. Replace the ink roller or ribbon

Faint, grey or patchy print with the paper moving normally means the ink is used up. Turn the power off, remove the printer cover, lift the old roller out and press the new one firmly into place. The common types:

• Casio HR series (HR-100TM, HR-150RC, HR-170RC, HR-200RC): ink roller IR-40T
• Compact Sharp models (EL-1801V, EL-1750V): ink roller EA-772R
• Canon P170-DH: ink roller CP-13
• Larger desktop machines (Victor 1280-7 and 1240-3A, Sharp EL-2196BL, Canon MP11DX): a two-colour ribbon on spools — Victor's is the 7010

Resist the urge to re-ink an old roller. Sharp warns in capitals that applying ink to a worn ink roller or use of an unapproved ink roller may cause serious damage to the printer. A new roller costs a few dollars; a flooded print mechanism ends the machine.

5. Clean the printing wheel

If the print is still dull with a fresh roller, dried ink has built up on the type wheel. Sharp's procedure: remove the cover and the ink roller, feed paper until it comes out at the front, then hold a soft brush (a toothbrush works) lightly against the printing wheel while you press the paper-feed key. Put the roller and cover back. Never turn the printing mechanism by hand — that can damage it.

6. Clear a paper jam

Casio shows a jam as P--Error, Sharp as P.E, and the printer stops. Turn the calculator off, tear the tape off, and pull the rest of the paper forward and completely out of the printer — not backwards. Before reloading, cut the end of the roll straight with scissors — Sharp warns never to insert a torn roll, because it will jam. Use paper of the width your model takes (most use 2¼″ rolls).

7. Reset it

If printing stops halfway or the calculator behaves strangely, Casio's answer is the RESET button on the back. It clears the memory, so note any stored values or tax rates first. If a reset does not bring it back, the manufacturer's advice is to contact the dealer.

8. Use the original adaptor

Both Casio and Sharp warn that any adaptor other than the specified one can damage the calculator (Casio HR-170RC/200RC: AD-A60024; Sharp EL-1611P: EA-28A). Switch the calculator off before plugging it in or out. A universal adaptor from the drawer with the wrong voltage or polarity is a classic way to kill the printer.

When it will not come back

Printing calculators wear out. Casio rates the printer in its HR-170RC at about 200,000 lines — a lot for a home desk, not that much for a bookkeeper who runs tapes all day. The usual signs are a motor that runs while the paper stays put, print that stays patchy with a new roller and a clean wheel, or a mechanism that grinds.

At that point the choice is a new machine or a different way of working. A new desktop printing calculator costs roughly $40 to $100; repairing an old one rarely makes sense against that. Both keep the running costs: paper rolls, ink rollers or ribbons, and power — around $11.50 a year on our own figures.

If you are replacing anyway, it is worth asking what you actually use the paper for. For most people it is the record: seeing every entry above the total, checking it, keeping it. That part does not need a printer.