Bixolon SLP-D420 4-inch direct thermal label printer

Name: Bixolon SLP-D420
Brand: Bixolon

Bixolon SLP-D420

A Bixolon 4-inch label printer that prints 104 mm wide on direct thermal media up to 116 mm wide. RS-232C, parallel, and USB ports are standard, and to cut labels one at a time, choose the factory-installed cutter model, which ships with DIP switch 1-7 set to ON.

Resolution

203 dpi (8 dots/mm)

Max print width

104 mm

Media width

25-116 mm

Drivers and manuals2 files

SLP-D420 specifications

Print method

Direct thermal (no ribbon)

Resolution

203 dpi (8 dots/mm)

Max print speed

152 mm/s (6 ips, DIP switch 1-1 ON) / 5 ips with 1-1 OFF

Max print width

104 mm

Media width

25-116 mm

Media roll

OD up to 130 mm, core 25.4-38.1 mm (1-1.5 in)

Interfaces

RS-232C (serial), IEEE1284 (parallel), USB / Ethernet on the SLP-D420E and D423E models

Emulation

SLCS, EPL, ZPL or DPL (DIP switch 2-5)

Media sensing

Gap or black mark (DIP switch 2-3); print-side black mark optional

Auto cutter

Factory-installed model, ships with DIP switch 1-7 ON

Media supply

Roll inside the unit, fanfold media through the rear opening, large rolls with the external media supply (optional)

Power

Adapter input AC 100-240 V 50/60 Hz, output DC 24 V

Operating temperature

0-40°C, humidity 10-80% RH

Storage temperature

-20 to 60°C, humidity 10-90% RH

300 dpi model

SLP-D423, print width 105.7 mm, up to 100 mm/s

The SLP-D420 is a Bixolon 4-inch label printer that accepts direct thermal media up to 116 mm wide and prints up to 104 mm across. RS-232C, IEEE1284 parallel, and USB ports come standard on the back, so it connects without a converter even to PCs that print through a parallel port.

There is the 203 dpi base model and the 300 dpi SLP-D423, and if you need Ethernet, choose the SLP-D420E or D423E. Both resolutions print direct thermal only, with no ribbon.

SLP-D420 ports and media specifications

Item	Details
Standard ports	RS-232C (screw lock), IEEE1284 parallel (clip lock), USB
Ethernet	SLP-D420E and D423E models
Media width	25-116 mm
Roll	OD up to 130 mm, core 1-1.5 in
Speed (203 dpi)	DIP switch 1-1 ON 6 ips, OFF 5 ips

The core inner diameter starts at 1 inch (25.4 mm), so rolls wound on a 0.5-inch core are outside the specification.

Auto cutter model

The auto cutter is a separate model installed at the factory. If the work requires cutting labels one at a time, choose the cutter model when purchasing; this model ships with DIP switch 1-7 set to ON (cutter present).

If 1-7 inside the bottom cover is changed to OFF, the printer operates as if it has no cutter and does not cut labels. The cutter works again only after setting 1-7 back to ON and turning the power on again, and media is loaded along the same path as on the model without a cutter. Do not touch the blade.

Switch combination for black mark media

DIP switch 1-6 normally selects between label stock (OFF) and continuous thermal paper (ON). Only when 2-3 is turned ON to switch to black mark detection is 1-6 used to select the mark side: OFF reads marks printed on the back, and ON reads marks printed on the print side. Print-side mark detection is optional.

Fanfold media and large rolls

Rolls up to 130 mm OD fit inside the unit. Folded (fanfold) media and larger rolls are fed through the opening made by cutting out the rear media supply cover with a knife; large rolls are hung on the external media supply, a separate optional part, and enter along the same path as fanfold media.

When to clean the sensors and roller

When print quality or media detection declines, clean the reflective sensor, gap sensor, platen roller, and media path. Turn the power off and remove the media, first brush off dust with a dry cloth or cotton swab, and wipe sticky residue with medical alcohol. Wait until the alcohol has completely dried, within 1-2 minutes, before turning it back on.

The Windows driver and user manual for the SLP-D420 are collected on the download page.

FAQ

What changes if I choose the SLP-D423?

At 300 dpi it prints 11.8 dots per mm, so small text and thin lines are denser. The print width is 105.7 mm, 1.7 mm wider, and the maximum speed is 100 mm/s, slower than the 152 mm/s of the D420.

A red light came on and printing stopped. Is it out of media?

If Status is steady red and Error blinks amber, the media is out; if Error blinks red, the media cover is open. If Status is off and only Error is steady red, it is waiting for a button press during sensor auto calibration.

How do I secure the parallel cable?

With the power off, plug the IEEE1284 cable into the PARALLEL port and fasten the clips on both sides. The serial cable is secured by tightening the screws on both sides.

Printing stops intermittently and then resumes.

If the two indicators show Status steady red and Error blinking green, the head has overheated and paused briefly. It resumes printing on its own once the head temperature drops.