The company was reacting to a report on German site Born's Tech and Windows World that claimed a recent firmware update appeared to block third-party ink cartridges from functioning correctly.
The writer, Günter Born, said a similar thing had happened almost exactly a year ago.
He said at that time, after some complaints HP had provided firmware to fix the problem.
He said a third-party printer cartridge vendor had sent him an email on 13 September claiming:
"There was a new firmware update today for the most popular HP Officejet printer models that prevents the use of alternative cartridges. The same update as exactly one year ago (13/09/2016).
"This firmware update has been confirmed by more than 50 customers. Also other third party cartridge vendors confirmed that. Our phones doesn’t stop ringing since yesterday morning."
Born said HP's Dynamic Security Feature appeared to be causing the problem.
He found that the US HP support page addressed the issue.
"HP’s new firmware update seems to force HP’s Dynamic Security Feature to block non-HP cartridges. A description of this feature may be found here. But there is a fix.
"HP provides a new firmware update on its HP support page, that disables HP’s Dynamic Security Feature .
"Go to HP’s support page and search for a firmware update for your printer model. Download and install the new firmware.
"After deactivating the Dynamic Security Feature via firmware update, non HP ink cartridges should be accepted again," he wrote.
HP denied it had issued any such firmware update that blocked non-HP cartridges.
"No such firmware update occurred. HP continues to use various forms of authentication (including dynamic security) to prevent the use of cartridges with non-HP chips," a company spokesperson told iTWire.
"HP will continue to issue firmware updates in order to resolve bugs and improve customer experience."