Comment 2 for bug 408366

I encountered similar problem with the same printer type (M1522nf). hp-scan and scanimage succeed sometimes but also possibly fail halfway during the scan and scanimage gives the same output. hp-check -t find no warnings or errors.
stuckey reported a similar problem at https://answers.launchpad.net/hplip/+question/74176

I checked my /var/log/syslog and find that when scanimage fails some dumping information in http.c is logged:

Sep 17 18:58:03 SGTLSRV scanimage: sane_hpaio_read(maxLength=32768): User cancelled!
Sep 17 18:58:03 SGTLSRV scanimage: sane_hpaio_cancel: already cancelled!
Sep 17 18:58:03 SGTLSRV scanimage: http.c 344: invalid http_status=0
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=8
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=2048
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=7
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=2048
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=7
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=708
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=7
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=142
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=5
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=445
Sep 17 18:58:03 SGTLSRV scanimage: http.c 348: dumping len=7
Sep 17 18:58:03 SGTLSRV scanimage: http.c 188: timeout reading data sec_timeout=1

I guess it was because of scanimage's trying to scan via network, but M1522nf does NOT support network scanning, so the request will soon be timed out and scan process stops halfway.
I forced scanimage to connect via USB by using -d parameter, and till now the scanner is working well. However I need further tests to ensure the problem is completely solved.