HP C7769B Service Manual - Page 17

Troubleshooting The Priming Procedure Fails When the customer first receives the Printer, it is supplied with a set of four Start-up Printheads pre-installed in the Printhead Carriage. These Start-up Printheads are used for the priming of the tubes in the Ink Delivery System. When the Printer is powered ON for the first time, the Printer will automatically perform the priming process. Without the priming process, the customer will NOT be able to use the Printer. The initial startup assumes that the Start-up Printheads are installed, but the Printer cannot detect them because the Printer can only detect normal Printheads. If normal Printheads are installed during the initial startup, the Printer will request the User to remove them and check if they really have been removed. It will then request the User to install the Start-up Printheads. Also the Printer will request the User to install the Ink Cartridges if they have not been installed already. If the Ink Cartridges contain less than 20cc of ink (the Ink Cartridges are encoded with the quantity of ink remaining) they will be rejected. Normally with a new Printer this should not be a problem since the Printer comes with Ink Cartridges that are full, but there maybe cases when the Ink Supply Tubes need to be replaced, in which case half empty Ink Cartridges may be used. Once the Printer assumes that the Start-up Printheads and Ink Cartridges with enough ink are installed, the priming process will begin. If the priming process is completed successfully, the Printer will directly proceed to the Printhead replacement procedure in order to replace the used Start-up Printheads with normal Printheads. Once the priming process has started, it can fail due to 2 different problems: n The Ink Supply Tubes were not completely empty - This is the most common cause especially if the Printer has been powered ON and OFF several times with the Ink Cartridges installed since the initialization process performs at least one pumping cycle. n The Printer detects that one or more of the tubes cannot be detected as filled with ink - The most likely cause for this problem is Ink Cartridges with a faulty valve. Even if the priming process fails, the Printer will try to verify whether the priming process has been completed by moving the Carriage to the access position and you will see the following HP DesignJets 500 and 800 Series Printers Service Manual 1-7