You place a document on the glass of your Canon PIXMA TS6420a, hit scan, and nothing reaches your computer or phone. The printer side seems fine, the lights are on, and copies still come out, but the scan job either times out, throws an error, or never appears in your scanning software. Because the TS6420a is a wireless 3-in-1 that depends on a stable network link and the right driver, a scanner that "won't work" is almost always a connection or software hiccup rather than a broken scanning unit.
The good news is that the flatbed scanner inside this model is genuinely capable (a Contact Image Sensor unit rated up to 1200 x 2400 dpi optical resolution), so the hardware is rarely the issue. Work through the fixes below in order, starting with the quickest checks and finishing with the official reset and support paths, and you should have it scanning again without guesswork.
Start With Power, Cables, and a Fresh Restart
Canon's own scanner troubleshooting checklist begins with the simplest items, and they resolve more cases than people expect. First, make sure your scanner or printer is turned on. A printer that looks awake but has dropped its connection will still fail every scan request.
If you scan over USB, the cable and the port matter. Connect the USB cable to a different USB port on the computer.
If the USB cable is connected to a USB hub, remove it from the USB hub and connect it directly to a USB port on the computer.
If you are scanning over a network (Wi-Fi) connection, check the connection status and reconnect as needed.
Restart the computer, then try scanning again.
A restart clears stuck driver processes and forces the scanning software to re-establish its link to the printer. Run this step even if everything looks normal, because it is the fastest way to rule out a temporary software state.
Put the Printer and Your Device on the Same 2.4 GHz Network
The TS6420a connects by Wi-Fi only (802.11b/g/n on the 2.4 GHz band, with no wired or Ethernet option per Canon's spec) and has no 5 GHz band. That means the printer and whatever you scan with (computer or phone) must be joined to the same 2.4 GHz network, or wireless scanning simply cannot find the device.
This trips up a lot of modern home setups, because many routers broadcast a 2.4 GHz and a 5 GHz network under names that look similar. If your laptop or phone is sitting on the 5 GHz band, it will never see a printer that only speaks 2.4 GHz.
Run through Canon's wireless checks in order. Check the power of the printer, the router, and your scanning device.
Next, make sure Wi-Fi is enabled on your device.
Then confirm the printer shows the Wi-Fi icon on its LCD screen.
Finally, make sure the network settings of the printer (such as the network name (SSID) or network key (password)) are identical with those of the wireless router.
It also helps to keep the printer near the router and away from interference sources such as microwaves. Weak signal and radio noise can cause scans to start and then stall partway through.
Reinstall MP Drivers When ScanGear Refuses to Launch
If your scanning application cannot start the scanner driver (ScanGear) at all, the driver package is usually missing, mismatched, or pointed at the wrong device. Canon lays out four checks for this exact situation.
Check 1: Make sure MP Drivers is installed. If it is not installed, install MP Drivers from the Setup CD-ROM or from Canon's website. The driver and scan-utility installers for the TS6420a live on the official model support page.
Check 2: Select your scanner or printer on the application's menu. If the printer's name appears multiple times in that list, select the one that does not include WIA. Choosing the WIA entry instead of the TWAIN driver is a common reason ScanGear will not open.
Check 3: Make sure the application supports TWAIN. You cannot start ScanGear (the scanner driver) from applications that do not support TWAIN.
Check 4: As a workaround, scan and save images with IJ Scan Utility, then open the saved files in your application. This lets you keep working while you sort out the driver path.
Let the Scan Utility Through Your Firewall
Security software is a frequent silent culprit. As Canon puts it, a firewall function may limit communications between a printer and a computer, and this may disable printer setup and communications. When that happens, scans fail with no obvious cause because the request never leaves your machine.
If you are prompted by your security software during setup, choose to enable communications. If you still cannot connect, you can temporarily disable the firewall function of the security software or operating system to test, and if you do that, disconnect your network from the Internet first as a precaution.
On Windows, a cleaner approach is to add a specific exception rather than turning the firewall off. Add a check mark for IJ Scan Utility in the Windows firewall allowed-apps list for the network profile you are using (Private or Public), then restart the machine and try scanning again.
Test a Different Scan Path to Find the Real Fault
When one method keeps failing, switching paths tells you whether the problem is the scanner itself or just one route to it. If the result works through another path, your scanner hardware is fine and the original method is what needs attention.
Try scanning from the Canon PRINT app, which is free on the App Store and Google Play. It can start printing and scanning over your local network, so a successful mobile scan confirms the printer and its scanner are healthy.
On a Mac, you can also try scanning through a different route, such as Apple's Image Capture, without relying on the full Canon driver. If any one of these works, focus your effort on repairing the path that failed rather than suspecting the scanner.
Diagnose and Repair the Connection With Canon's Network Utility
If the printer is clearly on Wi-Fi but your computer still cannot reach the scanner, let Canon's dedicated tool do the detective work. The IJ Network Device Setup Utility allows you to diagnose or repair the network status, and to manage printers on the network.
The utility lists detected printers with status icons that tell you what is wrong at a glance: available, not connected or not configured, a duplicate IP address, or unable to communicate. From there, it can diagnose the settings of the printer and computer if anything is wrong with the connection, and it repairs the status of the printer and computer.
This is the right tool to reach for before resetting anything, because it can often fix the link in place without forcing you to redo your whole Wi-Fi setup.
Reset the Network Settings and Redo Wi-Fi
If the connection is still broken after the diagnostic utility, reset just the network portion so you can rebuild it cleanly. This clears only the LAN configuration and leaves your other printer settings intact.
On the printer, use this exact path:
- 1.Press the OK button to open the menu screen.
- 2.Go to Device settings.
- 3.Select Reset setting.
- 4.Choose LAN settings only, which sets the LAN settings back to the default.
After that reset, the printer must be set up on the network again before network scanning will work. Redo Wi-Fi from Device settings > LAN settings > Wi-Fi > Wi-Fi setup, then reconnect your computer or phone to the same 2.4 GHz network and test a scan.
Restore Factory Defaults, Then Reach Canon Support
When nothing above brings the scanner back, restoring every setting to default is the last self-service step. This is a destructive step, so be aware of what it changes before you commit to it.
On the printer, follow this path. Press the OK button to open the menu screen.
After the menu screen opens, go to Device settings.
Then select Reset setting.
Finally, choose Reset all, which sets all settings you made to the printer back to the default.
Reset all also resets the administrator password. The LCD display language, the print head position, and the CSR for SSL/TLS are not reset. Because this wipes your configuration, you must run setup again afterward, including rejoining your Wi-Fi network.
If the scanner still does not work after a full reset and fresh setup, the issue may need a closer look. Use the official Canon model support page for the TS6420a, or contact Canon support directly for further help.
Frequently Asked Questions
Why does my computer not see the TS6420a scanner even though Wi-Fi looks fine?
The most common reason is a network mismatch. The TS6420a uses 2.4 GHz Wi-Fi only, so if your computer or phone is connected to a 5 GHz network it will not find the printer. Confirm both devices are on the same 2.4 GHz network, that the printer shows the Wi-Fi icon on its LCD, and that the SSID and password match your router.
Can I scan from my phone if my computer is not working?
Yes. The Canon PRINT app, free on the App Store and Google Play, can start printing and scanning over your local network. A successful scan from the app confirms the scanner hardware is working, which means you can focus on fixing the computer-side path instead.
Why will ScanGear not start in my scanning program?
ScanGear will not launch if MP Drivers is not installed, if your application does not support TWAIN, or if the wrong scanner entry is selected. When the printer name appears more than once in the application's menu, choose the one that does not include WIA. You can also scan with IJ Scan Utility and open the saved files in your application as a workaround.
Will resetting the printer delete my scans or settings?
Resetting does not affect already-saved scan files on your computer or phone. Choosing LAN settings only clears just the network configuration, while Reset all returns every printer setting to default and also resets the administrator password. After either reset you must set the printer up on your network again before network scanning will work.
I scan over USB and it still fails. What should I check?
First confirm the printer is turned on. Then connect the USB cable to a different USB port on the computer, and if it is plugged into a USB hub, remove it from the hub and connect directly to the computer. Restart the computer and try again, since a fresh start often clears a stuck driver state.