I try to scan docutment from 4521F, but i cant save a PDF file, only tiff, jpeg and some other graphic format file to save with, how could i save as pdf file from this 4521F samsung printer?

You can scan document to multi-page TIFF file anf then use a TIFF to PDF Converter to convert all pages from the TIFF document to PDF file.

Might need a bit more information about this: But I'm presuming you scan your document and save it as a pdf document using the built in HP software?
Couple of things to try:
1 - have you got the latest version of Adobe Reader? It may be that you are using an older version - the pdf document specification has been updated over the years and it may be that you're saving the pdf using a newer version of the pdf format than adobe reader is able to read.
2 - Adobe reader isn't the only pdf viewer, there are numerous other pdf document viewers (some free some not) You could try another pdf viewer, like Foxit Reader (free to use) and see if that can open it?
3 - When you save the scan, make sure that in the Save Dialog box it is really saving it as pdf. Common mistake is that people often just save a file with .pdf and expect the program to know that you want to save as pdf. When you scan there are several other file formats that you can use (Tiff, Jpeg etc) Is is possible you're saving the file as Tiff or Jpeg but with a .pdf file extension? If you're not sure, re-scan the document and resave it, but don't use a file extension, let the scanning program do that, see what it saves it as?
4 - check where you're saving the pdf on your computer? Is the place you're trying to open it from, the same as the place you've saved it?

You are going to want to find any OCR software that works for your printer. OCR is 'Optical Character Recognition'. It will take the scan and convert it into a text document, which is either already compatible for MS Word, or easily converted itself.

INSTALL PRESTO MANAGER IN THAT ICONS WILL BE THERE LIKE PAINT MS WORD JPG TIFF PDF CLICK THAT ICON AFTER SCANNING SCANNED IMAGE WILL BE SAVED IN REQUIRED FORMAT

Save the scanned image as a TIFF for archiving. TIFF files can beresaved and edited without compression loss, thus maintaining the highquality of an image. If you are enlarging an original 4 x 6 photo to8.5 x 11, save the scanned image as a TIFF at 600 dpi resolution. TIFFsprovide more detail than other file formats. Scanned images for emailand posting on the Web, which are to be viewed on a monitor, should besaved as JPEGs at 75 or 100 dpi. JPEGs generate smaller file sizes,which download faster on the Internet. Increase the resolution to 150or 300 dpi only if you are emailing a scanned JPEG image for therecipient to print. Save JPEGs at the maximum quality setting.

I need the scanned documents be saved as pdf in HP scanjet 5590

You probably need to flatten the image to get it into a background layer only. Choose in menu: Layer/Flatten image then try to save your image.

If it didn't work, then most likely your image is in 16 bits/channel mode, change it to 8 bits/channel. Choose in menu: Image/Mode/8 bits/channel.

JPEG gives small size outputs as compare uncompressed TIFF. This is probabbly the best for color. Try reducing the resolution to 150-300 dpi.

S. Mohan, Chennai, India

You have to scan with Adobe Reader in order to scan and save a pdf