Printing

node-zpl produces ZPL text; sending it to a printer is up to you. The printer's firmware does the drawing.

Sending ZPLCopy Anchor Link

Networked Zebra printers accept raw ZPL on TCP port 9100:

import { connect } from "node:net";

const socket = connect(9100, "192.168.1.50", () => socket.end(label.toZPL()));

Printers connected over USB, serial or Bluetooth take the same text through their connection, and print servers usually pass it through untouched. Browsers can't open TCP connections, so web apps send labels through a server, Zebra's Browser Print app, or WebUSB.

ResolutionCopy Anchor Link

Positions in ZPL are in dots, and dot size depends on the printhead. The same ZPL prints at different physical sizes on different printers, so the label's dpmm has to match the printer you send it to.

^ and ~ commandsCopy Anchor Link

Format commands start with ^. The printer collects them between ^XA and ^XZ and prints them as one label. Control commands start with ~ and act as soon as they arrive, like ~SD for print darkness. That's why printer settings live in PrinterSetup rather than Label:

import { PrinterSetup } from "node-zpl";

const setup = new PrinterSetup().setDarkness(20).toZPL();

Storing graphicsCopy Anchor Link

Send an image once and recall it by name in every label, instead of including it each time:

import { readFileSync } from "node:fs";
import { Label, PrinterSetup, mm, dots } from "node-zpl";
import { ImageConverter } from "node-zpl/image";

const graphic = await new ImageConverter().toZPL(readFileSync("logo.png"));

// Once: store it in the printer's RAM (R:) or flash (E:)
const setup = new PrinterSetup().storeGraphic({ name: "LOGO", graphic, device: "E" }).toZPL();

// In every label
new Label({ width: mm(57), height: mm(19), dpmm: 12 })
  .drawStoredGraphic({ position: { x: dots(0), y: dots(0) }, name: "LOGO", device: "E" });

Graphics in RAM are lost when the printer turns off; flash keeps them.

FontsCopy Anchor Link

Font 0 is Zebra's licensed CG Triumvirate Bold Condensed, and fonts A to H are built-in bitmap fonts. Previews use lookalikes, so text can come out slightly wider or narrower on the real printer. Leave some room at the end of lines that need to fit.