400B721n

OKI B721n Error 400: Memory Processing Issue

The OKI B721n error 400 typically occurs when the printer memory buffer is overwhelmed by a heavy print job. This error code suggests that the device cannot process the incoming data packets correctly. A simple print queue purge and a hard power reset are usually sufficient to restore standard operation.

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Common causes

  • 1Buffer overflow due to large file data.
  • 2Network print spooler corruption.
  • 3Driver incompatibility issues.
  • 4Hardware defect in the RAM module.

Solutions

Diagnóstico rápido

The error 400 occurs when trying to print graphics-intensive files. If the printer stays in an error state without printing, the buffer is likely saturated.

Solución paso a paso

  1. Open the "Print Spooler" on your computer and cancel all pending items.
  2. Power off the OKI B721n and disconnect any USB or network cables.
  3. Wait 60 seconds, then power the unit back on.
  4. Attempt to print a device test page to verify hardware functionality.

Prevención y mantenimiento

Avoid sending files with excessive DPI settings for normal office documents. Keep the device driver updated and perform routine printer cache clearings via the administrative interface.

Cuándo llamar a un técnico

If the error 400 remains visible without any active print tasks, it may indicate a malfunctioning memory DIMM that requires replacement.

Ficha técnica del equipo

  • Technology: Network Laser Printer
  • Performance: 47 ppm
  • Connectivity: USB 2.0, Ethernet 10/100
  • Feeding Capacity: 630 sheets
  • Consumables: OKI B721 / B731 series (45488801)
  • Recommended Use: Enterprise printing
  • Drivers / Official Firmware

Steps to follow

  1. 1

    Clear Print Queue

    Cancel all pending print jobs from your computer's print spooler.

  2. 2

    Power Off

    Shut down the printer and disconnect it from the network for a minute.

  3. 3

    Restart Device

    Power the printer on and try sending a test document.

Frequently asked questions

Error 400 generally indicates that the printer's RAM is overloaded while processing a large or complex file.

No, it is usually temporary and resolves by flushing the device memory.

This unit uses the OKI B721/B731 series toner cartridges.

Avoid sending extremely high-resolution PDF files directly to the printer.