Zebra ZD421D 4-inch Direct Thermal Desktop Label Printer (Model ZD4A042-D0EM00EZ) – 203 dpi, USB, Ethernet, Bluetooth LE, Print DNA

The Zebra ZD421D (ZD4A042-D0EM00EZ) is a 4-inch direct thermal desktop label printer designed for environments where a reliable, flexible, and secure printing solution is needed. It is part of Zebra’s evolved ZD400 series, offering several enhancements over older GK / ZD420 models in processing power, connectivity, and manageability.

Core Features & Benefits

Wide Printing Capability

With a maximum print width of approximately 104 mm (4.09 in), this model is suitable for a broad range of label types—from shipping/parcel labels to product tags, pallet labels, and more.  The 203 dpi resolution gives good clarity for standard barcodes, text, and simple graphics. 

Speed & Efficiency

The printer can output labels at speeds up to 152 mm/s (≈ 6 in/s) under ideal conditions—making it suitable for moderate to high throughput tasks in offices, warehouses, or retail settings. 

Connectivity & Flexibility

This variant comes with USB, USB Host, Ethernet, and Bluetooth LE (for configuration and potentially mobile print). The modular design also allows field upgrades (e.g. adding Wi-Fi) if needed in the future. 

Software & Manageability

Zebra’s Print DNA suite is baked in, enabling easier setup, diagnostics, remote firmware updates, and advanced monitoring & security.  The printer supports multiple command languages (EZPL, ZPL II, EPL2), and can emulate legacy printers via virtual devices to simplify migration. 

Operational Design & Usability

Media loading is intuitive, with color-coded guides and an open-access design. The printer includes moveable media sensors to support a variety of label media types.  The interface status LEDs and buttons are simplified for quick user interaction. 

Use Cases & Applications

• Shipping / logistics labeling (parcel, carton, pallet)

• Barcode labels, product tags, asset labels

• Office / administrative labeling tasks

• Retail shelf signage

• Light manufacturing / assembly line tagging

Considerations & Limitations

• As a direct thermal printer, labels are sensitive to heat, UV, and chemical exposure—long-term durability is lower than thermal transfer.

• It is optimized for standard label use; extreme duty/rugged label jobs may require industrial models.

• Connectivity beyond the built-in USB/Ethernet/BLE may require purchasing modular upgrades (e.g. Wi-Fi) in some variants.