Receipt printer setup

RKCoders POS prints through Windows, so any printer with a working Windows driver will do. There is no separate printer driver to install for the app itself.

Before you configure anything

Install the printer in Windows first and print a Windows test page. If Windows cannot print to it, neither can the till, and you will save yourself an hour by finding that out now.

Choosing the printer

Open Settings and find the printer section. It lists the printers Windows can see; pick yours.

Paper size

Three options, and this must match the paper actually in the machine:

• 58 mm — narrow thermal roll. Compact, but tight for long product names.
• 80 mm — the standard thermal receipt width and the right default for most shops.
• A4 — ordinary paper. This is a full-page invoice, not a stretched receipt: seller and customer side by side, one row per item, totals and a VAT summary, and the QR at the foot. Use it for tax invoices, or if you have no thermal printer.

Silent and automatic printing

Two settings that decide how much clicking a cashier does:

• Silent printing sends the job straight to the printer with no Windows print dialogue. Turn this on. Without it, every sale ends with a dialogue box.
• Automatic printing after payment prints the receipt as soon as the sale completes.

Together they mean the cashier takes payment and the receipt appears. For a shop where most customers do not want a receipt, you may prefer to leave automatic printing off and print on request.

Copies, font size and logo

• Copies — one to five. Two is common where a signed copy is kept for card payments.
• Font size — turn it up if your customers struggle with small print; turn it down to fit more on a 58 mm roll.
• Logo — upload or replace it under Settings → Printing or Company / Seller identity. A wide logo uses the full receipt width; a smaller logo keeps its real size and is not stretched. The printer section can hide the image without removing names or VAT.
• Extra header lines — two optional short lines can appear below the seller details for a branch name, slogan, licence number, or other receipt text.

Receipts start at the top of the printable area without an unnecessary blank band. The seller’s English and Arabic addresses print in darker, larger text, with national-address parts separated clearly. Labels stack English over Arabic in two columns so the right edge of an 80 mm or 58 mm roll is not cut off, and every line prints in solid black.

Cash drawer

Most shop drawers open from a kick pulse on the receipt printer, not from the till PC itself. The command is different for Epson, Star, Citizen and a few others.

In Settings → Printing, turn on Send an open pulse, pick the receipt printer (or the printer the drawer is actually wired to), then choose a command:

• Epson / Citizen pin 2 — the usual default. Try this first.
• Epson pin 5 — the other RJ-11 pin on many Epson printers.
• Star — ESC BEL, common on Star TSP models.
• Star / generic BEL — a single BEL byte, used by some older or generic mechanisms.
• Custom hex — paste the open-drawer bytes from your printer manual, space-separated, for example 1B 70 00 32 FA.

You can also set the pulse length for Epson-style commands if the drawer clicks but stays shut, and whether the till should kick only from the Cash drawer button, after a cash sale, or after every sale.

Use Test kick before you rely on it at the counter. The printer must use a driver that accepts RAW jobs (almost all ESC/POS thermal printers do). If Windows can print a receipt but the drawer never moves, try the other pin or the hex from the manual.

Test print

Use the test print button. Do not skip it, and do not treat the first real customer as the test.

Check the whole receipt: the store name and address, the seller VAT number, the layout across the full width, and the ZATCA QR code. Under the footer, the invoice number is also printed as a barcode so it can be scanned. The receipt is sent as one page; the printer should cut only after that barcode and the short blank feed below it. Scan the QR with a phone and confirm it returns your seller details. Scan the barcode and confirm it reads the invoice number.

If the QR is missing or unreadable, look at the seller details in Settings and at whether the print density on a thermal printer is high enough. A faint QR that a phone cannot read is a compliance problem, not a cosmetic one.

Receipts now print the QR larger, with a white quiet zone around it and high error correction, so a light or slightly blotchy thermal print still scans. Raise the printer’s darkness / density if a phone still fails — the QR itself cannot be made darker than solid black.

PDF and email

Every document can be saved as a PDF or emailed instead of printed. Business customers often prefer this, and it works from the Documents screen for past invoices too, not just at the point of sale.

Standard tax invoices and A4

Business customers with a VAT number receive standard tax invoices. On A4 that is a page laid out as an invoice. On a 58 mm or 80 mm roll it stays a receipt.

If you serve both walk-ins and business customers regularly, the practical setup is a thermal printer for everyday receipts and an A4 printer, or PDF and email, for tax invoices.

Kitchen tickets

A restaurant can send food to one kitchen printer while the table is still open. Payment later prints the customer receipt only. It does not send another kitchen ticket.

1. In Products → Categories, turn on Send to kitchen for each food category. Drinks or retail items you leave off stay on the bill and never print in the kitchen.
2. In Settings → Printing, turn on Print kitchen tickets, pick the kitchen printer, and choose 58 mm or 80 mm. Test kitchen ticket prints a sample with a table, items, and a line note. Silent printing uses the same switch as the receipt, so the cashier is not left on a Windows dialogue.
3. On the till, add the items. Select a line and press Comment to write a note such as “no onion”. Press Comment with no line selected to write a note for the whole order.
4. Press Send to kitchen. The first time, enter the table number or name. The till saves the open sale, prints the ticket, and clears the screen. The ticket has no prices, VAT, or QR. It shows the table, the sale number, the time, the cashier, the quantities, and the notes.
5. To add food, open the parked sale, add the items, and send again. The kitchen receives an ADD slip for the new quantity only. Removing or reducing something that was already sent prints a separate VOID slip.
6. If nothing changed, the till says the kitchen already has the order and does not print again. Reprint kitchen on the parked sale prints the last ticket marked REPRINT.
7. Take payment from the parked sale when the table is ready to leave. If food was added or removed and not sent, the till will not take payment until you send that change. Holding or parking a sale does not print a kitchen ticket. Stock moves when the sale is paid, the same as any other held sale.

On an Android till the same ticket opens the print dialog. There is no second named printer.

Barcode labels

Settings → Printing has a barcode-label section, separate from the receipt.

Pick a label printer, or leave it on the receipt printer. Then pick a size:

• Receipt roll prints one shelf label (name, price, barcode) per page on the 58 mm or 80 mm roll. If the receipt paper is A4, the same choice prints a sheet of labels.
• 40×30 mm and 50×25 mm print one die-cut sticker per page. Use these with a label printer, not the receipt roll.
• A4 sheet prints a grid of labels.

Test label sends one sample. Print a real run from Products → Print barcodes. You can also save the labels as a PDF. Copies are chosen per item there, not from the receipt copies setting.

Silent printing uses the same switch as receipts. Labels do not include the receipt header, logo, or QR.

When printing stops working

Work through it in this order:

1. Can Windows print a test page? If not, it is a Windows or hardware problem.
2. Is the printer still selected in Settings? A driver reinstall can change the printer’s name and leave the selection pointing at nothing.
3. Is the paper size right for the roll in the machine?
4. Is the queue stuck? Clear it in Windows.
5. Check the crash log for a printing error with a specific message.

One more thing to know: with ZATCA Phase 2 active, printing an uncleared standard tax invoice is deliberately held back until ZATCA clears it. If one specific invoice will not print while everything else does, check its ZATCA status before you suspect the printer.