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HP DeskJet 3840 Manual — Setup, Troubleshooting & WiFi Guide

The HP DeskJet 3840 is a compact color inkjet printer designed for home and small office use. This page provides complete setup instructions, wireless connectivity guidance, and comprehensive troubleshooting solutions to keep your printer running smoothly.

USB 2.0 Connection Color Inkjet Printer HP 65/65XL Cartridges
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Product Setup

1

Unpack and Position the Printer

Remove all protective materials and packaging from your HP DeskJet 3840. Place the printer on a flat, stable surface away from direct sunlight and heat sources. Ensure adequate ventilation around the device for optimal performance.

2

Connect Power and USB Cable

Plug the power cord directly into an electrical outlet (avoid surge protectors if possible). Connect the USB cable from the printer to your computer's USB port. Do not use USB hubs as this may cause communication conflicts.

3

Install Print Cartridges

Turn on the printer and open the cartridge access area. Install HP 65 or HP 65XL cartridges, ensuring they click securely into place. Remove the protective plastic tape from each cartridge before closing the access door.

4

Load Paper and Print Test Page

Load standard paper into the input tray, pushing it forward until it stops. Slide the paper guide firmly against the edge of the paper. Print a test page from your computer to verify the printer is functioning correctly.

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Pro-Tip: Do not touch the copper-colored contacts or the ink nozzles. Touching these parts can result in clogs, ink failure, and bad electrical connections.

WiFi Connection Guide

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Wireless Not Available

The HP DeskJet 3840 connects via USB 2.0 cable only. Wireless and WiFi connectivity are not supported on this model. For wireless printing, consider the HP DeskJet 3830, 3835, or 3845 series.

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USB Connection Best Practices

Connect the printer directly to your computer using a USB cable no longer than 5 meters (16 feet 5 inches). Avoid USB hubs and other USB devices on the same connection to prevent communication errors and printing conflicts.

Troubleshooting FAQ

Printer Is Not Printingexpand_more
Verify the printer is connected to power and turned on. Check that the USB cable is firmly connected directly to your computer (not a hub). Ensure print cartridges are correctly installed and paper is loaded in the input tray. Confirm the printer cover and rear access door are fully closed. If the printer does not turn on, disconnect the power cord for 10 seconds, then reconnect it. Try plugging directly into an electrical outlet rather than a surge protector.
Paper Jamexpand_more
Turn off the printer and disconnect power and USB cables. Remove paper from the input tray and check for any detached labels. Press the rear access door handle to the right and pull it out. Carefully remove the jammed paper from the back of the printer. Reattach the rear access door, reload paper, reconnect cables, and turn on the printer.
Print Quality Is Poorexpand_more
If pages show streaks, missing lines, or faded print, check that cartridges are not low on ink. Verify the black cartridge is installed for optimal black text quality. Ensure protective plastic tape has been removed from cartridges. For missing lines or streaks, clean the print cartridges. For too much or too little ink, open the Print dialog, select the Ink panel, and adjust the Ink Density slider. Consider selecting a higher print quality setting if text appears faded.
Document Is Misprinted or Prints at Wrong Angleexpand_more
Verify only one paper type is in the input tray and it is loaded correctly. Ensure the paper guide fits firmly against the edge of the paper. Check Page Setup dialog for correct paper size and orientation settings. For envelopes, slide the flap inside before loading and confirm the paper guide is snug. If text and images are misaligned, align the print cartridges. If parts of the document are missing, open Page Setup and set Scale to fit on paper, then set Layout to 1 (Normal) instead of Tiling.
USB Communication Errorexpand_more
If you see 'Error writing to USB port' or 'Printer not responding' messages, the USB cable may be too long or connected through a hub. Ensure the USB cable is no longer than 5 meters (16 feet 5 inches). Disconnect any USB hubs and connect the printer directly to a USB port on your computer. Try a different USB port if available. If problems persist, restart your computer and reconnect the printer.
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Important Safety Instructions

  • Use only HP 65 or HP 65XL genuine print cartridges for optimal print quality and reliability
  • Keep the printer cover and rear access door closed when not in use to prevent dust accumulation
  • Store paper in a dry environment to prevent moisture-related printing issues
  • Clean print cartridges when you notice streaks, missing lines, or faded output
  • Participate in HP's Planet Partner Program to recycle empty genuine HP cartridges responsibly
  • Avoid using surge protectors and connect power directly to electrical outlets for best performance

Replacement Ink Cartridges

The HP DeskJet 3840 printer uses genuine HP 65 / HP 65XL ink cartridges. Select your cartridge below to purchase replacement cartridges on Amazon:

shopping_cart Buy HP 65 on Amazon shopping_cart Buy HP 65XL on Amazon

Technical Specifications

Feature Specification
ModelHP DeskJet 3840 Series
Print CartridgesHP 65 (Standard) / HP 65XL (High Yield)
Print TechnologyColor Thermal Inkjet
ConnectivityUSB 2.0 Cable (Wireless Not Available)
Paper Input CapacityStandard input tray with paper guide
Supported Paper TypesPlain paper, photo paper, envelopes, labels, card stock
Related ModelsHP DeskJet 3830, 3835, 3845
Manual PDFDownload User's Guide
SupportVisit www.hp.com/support for drivers, updates, and customer assistance