If your HP DeskJet 3720 is producing pages with horizontal or vertical streaks, faded bands, or lines of missing ink, you're dealing with one of the most common print quality issues affecting this compact all-in-one printer. Streaking typically stems from clogged printhead nozzles, depleted or compromised ink cartridges, or incorrect paper settings. Fortunately, most HP DeskJet 3720 printing streaks can be resolved without professional printer repair using the systematic troubleshooting steps below.
Understanding What Causes Streaks on the DeskJet 3720
The HP DeskJet 3720 uses a thermal inkjet system with integrated tri-color and black cartridges. Because this model is designed for light home use with occasional printing, ink drying in the nozzles between jobs is a frequent culprit. Environmental factors like low humidity, using non-HP ink, or printing on incompatible paper stock can also trigger persistent streaking that standard cleaning cycles won't fix. Identifying whether the streaks appear in one color or all colors helps narrow down whether you're looking at a single cartridge problem or a broader printhead issue requiring deeper troubleshooting.
Step-by-Step Fix for HP DeskJet 3720 Printing Streaks
1
Run the Automated Printhead Cleaning Utility: On your computer, open the HP Smart app or HP Printer Assistant. Navigate to Print Quality Tools > Clean Printheads. The HP DeskJet 3720 will perform a cleaning cycle that forces ink through clogged nozzles. After completion, print a diagnostic page from the same menu. If streaks persist, run a second cleaning cycle—never exceed three consecutive cleanings without printing a test page, as excessive cleaning wastes ink and can degrade printhead performance.
2
Check Ink Cartridge Levels and Expiration Dates: Low ink often causes streaking before the printer triggers a low-ink warning. Open the HP Smart app and verify both the HP 65 black and HP 65 tri-color cartridges show adequate levels. Remove cartridges physically—press down to unlock, then pull outward—and inspect the expiration dates printed on each label. Expired cartridges can separate or thicken, causing inconsistent flow. If either cartridge is below 25% or past expiration, replacement is your most reliable fix printer solution.
3
Manually Clean the Printhead Contacts and Nozzles: Power off and unplug the printer. Remove both cartridges and set them on a paper towel with the copper contacts facing up. Dampen a lint-free cloth with distilled water (never tap water or alcohol) and gently wipe the copper-colored electrical contacts on each cartridge. Use a fresh damp cloth to lightly blot the nozzle plate where ink exits—do not rub or press hard. Allow 10 minutes of air-drying before reinstalling. This manual cleaning resolves many HP DeskJet 3720 printing streaks caused by dried ink residue or minor contact corrosion.
4
Align the Printheads and Calibrate Paper Type: Misalignment creates banding that resembles streaking. In HP Printer Assistant, select Print Quality Tools > Align Printheads and follow the on-screen prompts using the printed alignment page. Next, verify your print settings match your loaded paper: in the print dialog, click Properties > Paper/Quality and confirm the paper type (plain, photo, brochure) corresponds to what's in the tray. The DeskJet 3720 adjusts ink droplet size based on this setting, and mismatches cause smearing and streak-like artifacts.
5
Perform a Hard Reset and Update Firmware: With the printer powered on, disconnect the power cord from both the printer and wall outlet. Wait 60 seconds to drain residual charge, then reconnect and power on. This clears erroneous error states that can affect print quality. Then check for firmware updates in the HP Smart app under Advanced Settings > Printer Updates. HP periodically releases patches that resolve specific print quality bugs affecting the DeskJet 3700 series.
6
Replace Cartridges with Genuine HP 65 Supplies: If streaks remain after completing steps 1-5, at least one cartridge has internal damage or depleted ink reservoirs not visible through level monitoring. Install new HP 65 black (N9K02AN) and HP 65 tri-color (N9K01AN) cartridges—avoid refilled or third-party alternatives, which frequently cause color balance issues and accelerated printhead wear on this model. After installation, run one automated cleaning cycle and print a diagnostic report to confirm resolution.
⚠️ Important: Never use compressed air, vacuum cleaners, or sharp objects to clean your DeskJet 3720 printhead. These methods can damage the delicate nozzle plate, destroy the cartridge entirely, or push debris deeper into the ink delivery system. If manual cleaning with distilled water doesn't resolve HP DeskJet 3720 printing streaks, the printhead assembly itself may need replacement—contact HP printer support or a certified technician rather than attempting more aggressive DIY methods.
Preventing Future Streaking Issues
To minimize recurrence, print at least one page weekly to keep ink flowing through the nozzles. Store replacement HP 65 cartridges sealed in their original packaging at room temperature, and avoid exposing installed cartridges to direct sunlight or heating vents. When printing resumes after a multi-week idle period, always run a cleaning cycle before important jobs. For ongoing printer support, enable automatic firmware updates in the HP Smart app so your DeskJet 3720 receives the latest performance optimizations.
Frequently Asked Questions
Why does my HP DeskJet 3720 print streaks only in color?
Color-only streaks indicate a problem with the HP 65 tri-color cartridge specifically. The cyan, magenta, or yellow chamber may be clogged or depleted. Remove the cartridge and check which color is missing from the test pattern, then clean or replace that cartridge. If all colors streak equally, the integrated printhead on the tri-color cartridge has likely failed.
Can I use HP 65XL high-yield cartridges to fix streaking?
Yes—HP 65XL cartridges contain the same printhead technology with larger ink reservoirs. They're fully compatible with the DeskJet 3720 and can actually reduce streaking frequency because the higher ink volume keeps nozzles saturated longer between prints. However, if your current cartridge is causing streaks due to damage rather than low ink, switching to XL won't help until you replace the faulty unit.
How many cleaning cycles should I run before seeking professional help?
Limit automated cleaning to three cycles per day, with test prints between each. Excessive cleaning overheats the thermal printhead and wastes significant ink. If you've completed three cleanings, manual contact cleaning, alignment, cartridge replacement, and a hard reset without improvement, the issue likely requires hardware diagnostics from HP tech support or authorized printer repair service.
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