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Citizen CL-S631II-WUBK 4-Inch Desktop Thermal Label Printer with 300 DPI Resolution and WiFi Connectivity

Brand Citizen

Model Number CL-S631II-WUBK

UPC

Manufacture Warranty

EpicRise Warranty 1 Year

Product Highlights

• 300 DPI high-resolution printing for detailed logos, 2D barcodes, and EAN-compliant labels with exceptional clarity

• Thermal transfer printing with 360-meter ribbon capacity for extended production runs and minimal downtime

• Hi-Lift metal mechanism and ARCP anti-wrinkle technology ensure effortless media loading and consistent print quality

• WiFi, USB, and RS-232 connectivity with Cross-Emulation for Zebra and Datamax compatibility in mixed printer environments

• ENERGY STAR certified with integrated power supply for reliable operation and compact workspace footprint

Overview
Specifications
FAQ
User Guides
Reviews

The Citizen CL-S631II-WUBK is a high-resolution desktop thermal label printer engineered for enterprise environments requiring precise barcode reproduction and professional label quality. With 300 DPI resolution and thermal transfer printing mode, this printer delivers exceptional clarity for 2D matrix barcodes, company logos, and regulatory markings. The powerful 32-bit processor with 16MB RAM ensures rapid throughput at 4 inches per second, completing a typical shipping label in approximately one second.

Built with Citizen's proprietary Hi-Lift metal mechanism and ARCP color ribbon control technology, the CL-S631II-WUBK eliminates common printing issues like ribbon wrinkles and unreadable labels. The Hi-Open vertical-opening casing provides easy access without expanding the printer's footprint, while supporting up to 360-meter ribbon rolls for extended production cycles. Integrated WiFi, USB, and RS-232 connectivity combined with Cross-Emulation technology allows seamless integration into existing workflows using Zebra or Datamax command sets.

Best For

The CL-S631II-WUBK is designed for enterprises requiring high-resolution label printing in space-constrained environments:

- Pharmaceutical and Medical Device Labeling: Print small labels with Datamatrix, QR codes, and regulatory symbols (CE, WEEE) at compliance-grade resolution for product tracking and serialization

- Electronics Manufacturing: Create detailed component labels with 2D barcodes and corporate branding for inventory management and quality control processes

- Retail and E-Commerce Fulfillment: Generate professional shipping labels with logos and barcodes for multi-carrier shipping operations requiring brand consistency

- Laboratory and Healthcare Specimen Tracking: Produce durable thermal transfer labels for small sample containers and test tubes with high-density barcode information

- Asset Management and IT Operations: Print asset tags with detailed information, including PDF417 barcodes and company identifiers for equipment tracking

Key Features

- 300 DPI resolution delivers sharp reproduction of fine text, detailed graphics, and high-density 2D barcodes including Datamatrix, QR Code, DataBar, and PDF417

- Thermal transfer printing mode provides permanent, durable labels for outdoor use and long-term applications requiring resistance to environmental conditions

- 360-meter ribbon capacity with internal and external ribbon options reduces media changeouts and maximizes production uptime in high-volume environments

- Hi-Lift metal mechanism with Hi-Open vertical casing enables tool-free media loading without increasing desk space requirements

- ARCP anti-wrinkle ribbon control technology automatically adjusts tension to eliminate print defects and wasted labels

- Cross-Emulation technology supports Zebra and Datamax command languages, enabling drop-in replacement without software reconfiguration

- WiFi 802.11b/g wireless connectivity with 64/128-bit WEP and WPA security allows flexible printer placement without network cabling

- ENERGY STAR certified with integrated power supply eliminates external adapters and reduces energy consumption in always-on environments

Quick Specs

Print Technology	Thermal Transfer
Resolution	300 DPI
Print Speed	4 inches per second (100 mm/sec)
Maximum Print Width	4 inches (104 mm)
Media Width Range	0.5 to 4.6 inches (12.5 to 118 mm)
Media Length Range	0.25 to 64 inches (6.35 to 1625.6 mm)
Maximum Media Roll Diameter	8 inches (200 mm), 1-inch core
Ribbon Capacity	Up to 360 meters (internal/external ribbon)
Media Sensors	Adjustable gap, notch, and reflective black mark
Processor	32-bit
Memory	16MB RAM, 4MB Flash
Connectivity	WiFi 802.11b/g, USB 2.0, RS-232
Emulations	Cross-Emulation (Zebra, Datamax)
Barcode Types	1D: Code 39/93/128, CODABAR, EAN-8/13, UPC-A/E, ITF; 2D: Datamatrix, DataBar, QR Code, PDF417
Operating System Support	Windows 11, 10, 8.1, 8, 7 (32/64-bit)
Form Factor	Desktop
Weight	9.9 lbs
Certifications	ENERGY STAR
Warranty	2 years printer, 6 months or 50 km printhead
Optional Accessories	Guillotine cutter, basic peeler

What's Included

- CL-S631II-WUBK thermal label printer

- Power cord

Product Details
Color	Gray
Connection Type	USB, Wlan

What types of labeling operations is the CL-S631II-WUBK best suited for?

The CL-S631II-WUBK is designed for applications requiring high-resolution 300 DPI printing of small labels with 2D barcodes, logos, or regulatory symbols. It excels in pharmaceutical serialization, electronics component labeling, asset tagging, and specimen tracking where barcode density and print clarity are critical. The 4-inch print width handles standard shipping labels while the thermal transfer mode supports permanent outdoor labels requiring environmental durability.

How does the CL-S631II-WUBK compare to the CL-S521II in the same product line?

The CL-S631II-WUBK offers 300 DPI resolution compared to the CL-S521II's 203 DPI, enabling sharper reproduction of fine text, detailed graphics, and high-density 2D barcodes like Datamatrix and QR codes. Both models share the Hi-Lift mechanism and ARCP technology, but the CL-S631II-WUBK uses thermal transfer printing while the CL-S521II uses direct thermal. Choose the CL-S631II-WUBK when label quality, barcode scanability at smaller sizes, and permanent label durability are business requirements.

Is the 300 DPI resolution worth the investment for typical shipping and receiving operations?

The 300 DPI resolution provides measurable value when printing labels smaller than 2x2 inches, incorporating company branding, or using high-density 2D barcodes that require scanability from any angle. Operations printing only standard 4x6 inch shipping labels with basic 1D barcodes may find 203 DPI models more cost-effective. The CL-S631II-WUBK justifies its price point in regulated industries, quality-focused retail, or mixed-use environments requiring both detailed product labels and standard shipping documents from one device.

What systems and network environments is the CL-S631II-WUBK compatible with?

The printer supports Windows 11, 10, 8.1, 8, and 7 in both 32-bit and 64-bit versions. WiFi 802.11b/g connectivity with WEP and WPA security integrates into existing wireless networks with up to 100-meter range. Cross-Emulation technology enables compatibility with software designed for Zebra and Datamax printers without code modification. USB 2.0 and RS-232 serial ports provide additional connectivity options for legacy systems and direct device connections.

What is the maximum ribbon length and what runtime does this provide?

The CL-S631II-WUBK supports up to 360-meter ribbons in both internal and external configurations, significantly longer than standard 110-meter ribbons used in many desktop printers. At 4 inches per second and 4-inch label width, a 360-meter ribbon can produce approximately 3,500 labels before requiring ribbon replacement, depending on print density. This extended capacity reduces operator intervention and material changeover frequency in production environments.

Can the printer handle both small labels for products and larger shipping labels?

The printer accepts media from 0.5 to 4.6 inches wide and 0.25 to 64 inches long, covering both small product labels and standard shipping formats. The 4-inch maximum print width accommodates 4x6 inch shipping labels while the minimum 0.25-inch length enables tiny component or specimen labels. Media sensors detect gap, notch, and reflective black marks for reliable handling of different label stocks and formats within a single roll or across media changes.

What optional accessories are available to enhance the printer's functionality?

Citizen offers a guillotine-style cutter and basic peeler as dealer-installable accessories for the CL-S631II series. The cutter automatically separates individual labels for applications where backing paper retention is not needed. The peeler dispenses labels without backing for immediate application workflows. Both accessories require dealer installation and are ordered separately from the base printer unit.

What is the current product availability status of the CL-S631II-WUBK model?

Official Citizen documentation indicates this specific model may have reached end-of-life status with a suggested replacement model CL-S631II-EPWSUBK. Current inventory availability and ongoing support for the CL-S631II-WUBK should be verified with EpicRise Electronics or Citizen before purchase. Customers requiring this exact WiFi configuration should confirm part availability and timeline for the transition to newer model designations.