I have a HP deskjet3745 printer. I changed the ink cartridges and did the alignment and test print page, everything seemed fine but upon printing a picture from my HP scanner the picture comes out a very pale yellowish orange with no other color to it. I thought it may be the old paper I was using but it isnt as I also tried it with the same paper I did my test print on.

Try running cleaning cycle multiple times. Sounds like ink tubes may be clogged.

Important thing: HP inkjet printers having self align technology & its aligns automatically after replacing the ink cartridge/s.In the process of align it will prints align page &it will read it on the model.
Suppose if you replaced yellow cartridge, as usually it will print align page, but if one or more cartridges not printing properly align will not completes. Results every time it will prints the align page when its switching on. Align will completes only when all cartridges/print heads are in healthy condition.. Check the alignpage find out which colors are not printing properly, replace it to over come from this issue. Now you decide what to do?..

Have u recently changed ur ink cartridge ? If so the printer is printing an alignment page . Turn it off then on , so it prints the alignment page. load the alignment page on the scanner glass and press the "Scan" button to complete the alignment. Once the alignment has completed the alignment page will not be printed again until you change the next cartridge. See your user manual for details.

Replacing the print cartridges

1. Turn on the HP Officejet, and lift open the print-carriage access door. The print carriage will move into the access area. Figure 1: Opening the print-carriage access door
2. After the carriage stops moving, push down on the top of the print cartridge to release it, and then pull it toward you out of the slot. Figure 2: Removing the print cartridge NOTE: It is normal to see ink buildup in the print cartridge slots.
3. Remove the new print cartridge from the packaging and gently remove the plastic tape by using the pink pull tab. CAUTION: Do not touch the copper contacts or ink nozzles. Install the cartridge immediately upon removing the tape to prevent ink from drying in the nozzles. Figure 3: Removing the plastic tape
4. Push the new print cartridge into the appropriate slot at a slight angle, until it clicks into place. CAUTION: Do not attempt to push the cartridge straight into the slot. It must slide in at a slight angle. Figure 4: Inserting the print cartridge
5. Close the print-carriage access door.

Back to top Aligning the print cartridges The HP Officejet will prompt you to align the print cartridges every time you install a new print cartridge to assure high-quality output.

1. When the message displays, press OK . The HP Officejet will print an alignment page.
2. Place the alignment page face down on the left front corner of the glass with the top of the page facing the left side.
3. Press OK . The HP Officejet will align the print cartridges and display Alignment Complete .

If iam not wrong you want to replace the Ink Cartridge. Please follow the below mentioned instruction.

Replacing the print cartridges

1. Turn on the HP Officejet, and lift open the print-carriage access door. The print carriage will move into the access area. Figure 1: Opening the print-carriage access door
2. After the carriage stops moving, push down on the top of the print cartridge to release it, and then pull it toward you out of the slot. Figure 2: Removing the print cartridge NOTE: It is normal to see ink buildup in the print cartridge slots.
3. Remove the new print cartridge from the packaging and gently remove the plastic tape by using the pink pull tab. CAUTION: Do not touch the copper contacts or ink nozzles. Install the cartridge immediately upon removing the tape to prevent ink from drying in the nozzles. Figure 3: Removing the plastic tape
4. Push the new print cartridge into the appropriate slot at a slight angle, until it clicks into place. CAUTION: Do not attempt to push the cartridge straight into the slot. It must slide in at a slight angle. Figure 4: Inserting the print cartridge
5. Close the print-carriage access door.

Back to top Aligning the print cartridges The HP Officejet will prompt you to align the print cartridges every time you install a new print cartridge to assure high-quality output.

1. When the message displays, press OK . The HP Officejet will print an alignment page.
2. Place the alignment page face down on the left front corner of the glass with the top of the page facing the left side.
3. Press OK . The HP Officejet will align the print cartridges and display Alignment Complete .

Regards,
Shrey

hi Alignment of ink cartridges is very essential for the for the printer to print so first of all be sure that you are using geniun ink cartridges now lets try a reset on your printer press the # and 3 button on your printer together and then unplug the power cord from your printer and keep pressing the buttons now wait for 5 sec and while pressing # and 3 replug the power cord wait for the printer to initialize and see if it prints alignment page if no page is printed then click on the start button of the computer and then go to printers and faxes and then right ckick on the icon of your printer and click on printing preferences now go to the features tab and click on the button that says align print cartridges wait for the alignment page to print and now try and see if it prints fine

Always try replacing the ink cartridges first.

It sounds like the print heads in the 7780 are bad. Don't confuse the ink cartridges with print heads. The cartridges fit inside the print heads. You will need to change the heads. Here is a link to HP's how-to.
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00841890&tmp_track_link=ot_faqs/top_issues/en_us/c00841890/loc:1&lc=en&dlc=en&cc=us&lang=en&product=2512010

Could have the same problem with the Dell.

Replacing the print cartridges

1. Turn on the HP Officejet, and lift open the print-carriage access door. The print carriage will move into the access area. Figure 1: Opening the print-carriage access door
2. After the carriage stops moving, push down on the top of the print cartridge to release it, and then pull it toward you out of the slot. Figure 2: Removing the print cartridge NOTE: It is normal to see ink buildup in the print cartridge slots.
3. Remove the new print cartridge from the packaging and gently remove the plastic tape by using the pink pull tab. CAUTION: Do not touch the copper contacts or ink nozzles. Install the cartridge immediately upon removing the tape to prevent ink from drying in the nozzles. Figure 3: Removing the plastic tape
4. Push the new print cartridge into the appropriate slot at a slight angle, until it clicks into place. CAUTION: Do not attempt to push the cartridge straight into the slot. It must slide in at a slight angle. Figure 4: Inserting the print cartridge
5. Close the print-carriage access door.

Aligning the print cartridges The HP Officejet will prompt you to align the print cartridges every time you install a new print cartridge to assure high-quality output.

1. When the message displays, press OK . The HP Officejet will print an alignment page.
2. Place the alignment page face down on the left front corner of the glass with the top of the page facing the left side.
3. Press OK . The HP Officejet will align the print cartridges and display Alignment Complete .

A lot of HP printers print a page to enable the print head alignment and calabration. This normally orcurs when a cartridge has been changed. If the alignment page fails then it will reprint alignment page until it can align.

So, you need to get that page it prints and place it on the glass and press scan, then it will complete alignment and be ready to rock.

See Here

Cheers

I just got off the HP help line.  After changing my black ink cartridge a test page was printing each time I turned the machine on.  This is very costly, in both time and ink as the cartridges themselves for this machine hold very little ink.  I tried to learn from HP tech how to turn off the test-print while keeping my color cartridge empty.  It turns out that you cant do it.  HP requires you to keep buying and using cartridges whether you need them or not.If you buy the color ink it will use it up in its testings.  And if you dont buy the color cartridge it will use up your black ink by printing the test each time you turn on the printer.  The printer was inexpensive sure, but I'm paying for it in wasted ink.