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Note: From May 1, 2024, the HP Scan and Capture app will no longer be available (retired) in the Microsoft Store and HP will not release any further app updates. Alternatively, you can download HP Smart from the Microsoft Store. For more information on how to set up your printer using the HP Smart app, go to HP printer setup (HP Smart app).
Common problems HP Solution Center not working : Adobe Flash Player Error and Unable to scan
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HP Recommended
OfficeJet 4636

I recently purchased an HP OfficeJet 4636, and I notice that when scanning documents to PDF, the generated PDF files are always invalid. When opening these files in Acrobat Reader or Acrobat Pro, one gets the message "The file is damaged but is being repaired." Many other PDF tools can't open the files at all.

 

I have installed the newest firmware update and restarted the printer, but the problem was not solved.

 

I tried many different settings (e.g., resolution, paper size, scan from ADF, scan from Glass), but the problem is always the same. For the record, I am using the "Web scan" interface: http://XX.XX.XX.XX/#hId-pgWebScan.

 

If there were an opportunity to attach a file to this bug report, I would attach an actual PDF file generated by this printer. I am happy to supply the file later, and I will refer to this specific file in my analysis of the bug below.

 

I am familiar with Adobe's PDF definition:

 

PDF Reference, sixth edition. Adobe Portable Document Format
Version 1.7, November 2006. Abobe Systems Incorporated.

 

I examined the PDF file in detail and it is quite clear what the bug is. Object 1 of the PDF file starts at byte offset 10, and it is a stream object containing the main image data in compressed JPEG format. The Length field for the stream object (at byte offset 168) is set to 1051875. However, the actual compressed stream data is only 64914 bytes long.

 

This is incorrect, because the PDF Reference (Section 3.2.7, p.61, "Stream Extent") specifies that "If the stream has a filter, Length is the number of bytes of encoded data." (emphasis in original). In other words, the stream length should be set to 64914, which is the length of the JPEG encoded data, and not 1051875 (which is presumably the length of the raw unencoded image data).

 

Moreover, four of the entries in the PDF xref table (at offset 65504) are incorrect:

 

the byte offset for object 2 is given as 1052085 (actual location of object 2 is 65124);

the byte offset for object 3 is given as 1052140 (actual location of object 3 is 65179);

the byte offset for object 4 is given as 1052206 (actual location of object 4 is 65245);

the byte offset for object 5 is given as 1052383 (actual location of object 5 is 65422).

 

Also, the PDF startxref pointer (at offset 65674) points to 1052465, whereas the actual location of the xref table is byte offset 65504.

 

Note that in all six cases, the error is exactly equal to the difference between the declared stream length (1051875) and the actual stream length (64914):

 

1051875 - 64914 = 986961

1052085 - 65124 = 986961

1052140 - 65179 = 986961

1052206 - 65245 = 986961

1052383 - 65422 = 986961

1052465 - 65504 = 986961

 

It looks like this is a simple programming error in the printer's PDF generation software: all the offsets are computed as if the length of the embedded image stream were 1051875, whereas it is actually 64914.

 

I scanned at different page sizes, resolutions, and so on. Each time, the actual byte offsets were slightly different (depending on the length of the encoded image stream), but the above relationships still hold in each case.

 

Please fix this! It is not really acceptable for an HP scanner to produce broken PDF files. Thanks, -- Peter

 

18 REPLIES 18
HP Recommended

Hi @Selinger 

 

One of the important things to point out is that the Webscan feature was designed for diagnostic purposes. The intended method of scanning is with HP software and the software build into the OS.

 

For Mac users this includes Apple Preview, Image Capture, or scanning from the Print and Fax Window.

 

For Windows users, non HP software includes, Windows Live Photo GAllery, Paint, and Windows Fax and Scan.

 

Webscan is a great alternative, but it is very basic. Your best option it to install the HP software and us the HP Scan program.

 

If there is a particular reason you are using Webscan and prefer to scan this way, the only thing I can really suggest is to try a different browser.

 

Please let me know the outcome of a different Browser, what Browser you are currently using, and what happens when you scan with HP software. If you require further assistance, please also include your operating system. What operating system, and version do you have? Mac or Windows?

 

I hope this helps.

Sunshyn2005
I work on behalf of HP


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Hi Sunshyn,

 

thanks for your reply. I use the webscan feature because I am a Linux user, and scanning from a browser is far more convenient for me than installing special software.

 

Using a different browser does not solve the problem. In fact, the PDF file is generated within the printer itself - the errors that occur inside the PDF file are not the kind of errors that would be introduced by file transfer. Rather, the PDF itself is not syntactically well-formed. For example, here is the image stream object from inside the PDF file:

 

1 0 obj
<<
/Type /XObject
/Subtype /Image
/Name /Im0
/Width 1700
/Height 2178
/BitsPerComponent 8
/ColorSpace /DeviceRGB
/Filter /DCTDecode
/Length 1051875
>>
stream

.....

endstream

endobj

 

Except for the ".....", this is literally how it appears in the PDF file. However, the actual length of the stream is only 64914 bytes, so the 1051875 is definitely an error.

 

I believe that this is not so much a user support issue as a technical bug report. Could you please ensure that it is forwarded to someone from the technical side of HP?

 

Also, is there a way to attach a file here somewhere? I would like to send the original PDF file, to enable some technical person to examine it.

 

Thanks! -- Peter

HP Recommended

Hi @Selinger 

 

I have brought your issue to the attention of an appropriate team within HP. They will likely request information from you in order to look up your case details or product serial number. Please look for a private message from an identified HP contact. Additionally, keep in mind not to publicly post serial numbers and case details.

 

If you are unfamiliar with how the Forum's private message capability works, this post has instructions.

 

 

Sunshyn2005
I work on behalf of HP


If you found this post helpful, you can let others know by clicking the Accept as Solution button. You can also show your appreciation, with a kudos, by clicking the thumbs up" button!

HP Recommended

Great, thanks! -- Peter

HP Recommended

I have experienced the same problem using the scanning software from HP.  I can't provide the detail of the previouos poster, but I have noticed the file error only occurs with the first page.  My other .pdf files that I use don't have this problem.    I am able to read these files, but when I want to combine two files using a .pdf editor I cannot without rescanning the file and putting a blank page at the beginning.  Is there a fix?

HP Recommended

I never got anywhere with HP on this bug.

 

After forwarding my report to the "appropriate team", they kept demanding that I should translate my bug report into German (just because I bought the printer in Germany!). Also, they demanded that I should describe the bug "in my own words" - after I already wrote a very detailed technical description of the bug.

 

The last answer that I got from HP Support in Germany was that they "don't support Linux" - that's just an idiot's answer, considering that the problem is in the embedded webserver, and I received the same file from the printer, no matter which operating system I used to run my browser in. They also told me that I am not supposed to use the embedded web server's "scan" feature because that feature was not advertised on the box and is therefore not a supported feature.

 

Eventually I got frustrated with the fact that they kept writing to me in German. Apparently the bug report never made it to any technical person at HP who actually understands the format of a PDF file, or the people who actually program the embedded webserver. This bug is so basic that it could be fixed in 30 seconds. I could fix it myself if I had the source code.

 

Oh well. There's no workaround that I know of. Adobe Reader will "fix" the file alright, but will not allow you to save the fixed file. I ended up scanning everything to the JPG format and then converting it to PDF manually. But this is a pain because you have to scan one page at a time and can't use the automatic feeder.

 

 

HP Recommended

One more question, maybe this will be easier to answer for HP: why does it say "Honor Student" below my name? I am certainly not a student, and whether I'm honorable, I will not say 🙂

 

HP Recommended

Ah, apparently that is their ranking system. Apparently now I have become a "top student" because of my amazing contributions to this forum. Hopefully, if I regularly attend class, the good teachers at HP will give me an "A".

HP Recommended

You are on the honor roll because you give honest answers.

† The opinions expressed above are the personal opinions of the authors, not of HP. By using this site, you accept the <a href="https://www8.hp.com/us/en/terms-of-use.html" class="udrlinesmall">Terms of Use</a> and <a href="/t5/custom/page/page-id/hp.rulespage" class="udrlinesmall"> Rules of Participation</a>.