当我在简单扫描应用程序中选择textopton（大绿色扫描按钮旁边的小箭头）时，结果是灰度 pdf，效果很好。如果我选择imageoption，我会收到 IO 错误。我也尝试了其他前端，它们在颜色扫描期间也会失败，skanlite 甚至可以向我显示一点彩色预览，然后它也会抛出错误。我的打印机没问题（可以使用 OSX、Windows 扫描彩色页面）。
我记得彩色扫描在这台机器上已经可以使用了，但过了一段时间（和几次更新）。有一次我意识到扫描根本不起作用。经过一番研究，我设法让灰度扫描工作，但颜色扫描却没有成功。有人能帮我吗？
一些信息：三星 M2070 打印机通过 USB 连接到 Ubuntu 18.04 PC，
软件版本：
- libsane1：libsane1/bionic-updates，现在 1.0.27-1~experimental3ubuntu2.2 amd64 [已安装]
- libsane-common：libsane-common/bionic-updates，bionic-updates，现在 1.0.27-1~experimental3ubuntu2.2 全部 [已安装]
simple-scan -d 的输出：
(base) czeman@czeman-H87M-HD3:~$ sudo simple-scan -d
[+0,00s] DEBUG: simple-scan.vala:637: Starting Simple Scan 3.28.0, PID=2312
[+0,02s] CRITICAL: g_action_print_detailed_name: assertion 'g_action_name_is_valid (action_name)' failed
[+0,02s] CRITICAL: gtk_application_set_accels_for_action: assertion 'detailed_action_name != NULL' failed
[+0,04s] DEBUG: app-window.vala:1714: Loading state from /home/czeman/.cache/simple-scan/state
[+0,04s] DEBUG: app-window.vala:1671: Restoring window to 1105x567 pixels
[+0,04s] DEBUG: autosave-manager.vala:64: Loading autosave information
[+0,04s] DEBUG: autosave-manager.vala:259: Waiting to autosave...
[+0,09s] DEBUG: scanner.vala:1454: sane_init () -> SANE_STATUS_GOOD
[+0,09s] DEBUG: scanner.vala:1460: SANE version 1.0.29
[+0,09s] DEBUG: scanner.vala:1521: Requesting redetection of scan devices
[+0,09s] DEBUG: scanner.vala:806: Processing request
[+0,14s] DEBUG: autosave-manager.vala:281: Autosaving book information
[+0,26s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+4,07s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+5,45s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+11,77s] DEBUG: simple-scan.vala:454: Requesting scan at 150 dpi from device '(null)'
[+11,77s] DEBUG: scanner.vala:1569: Scanner.scan ("(null)", dpi=150, scan_mode=ScanMode.COLOR, depth=8, type=ScanType.SINGLE, paper_width=0, paper_height=0, brightness=-10, contrast=-17, delay=10000ms)
[+11,88s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+24,59s] DEBUG: scanner.vala:341: sane_get_devices () -> SANE_STATUS_GOOD
[+24,59s] DEBUG: scanner.vala:353: Device: name="xerox_mfp:libusb:003:004" vendor="Samsung" model="M2070 Series" type="multi-function peripheral"
[+24,59s] DEBUG: scanner.vala:806: Processing request
[+24,59s] DEBUG: scanner.vala:867: sane_open ("xerox_mfp:libusb:003:004") -> SANE_STATUS_GOOD
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (0)
[+24,59s] DEBUG: scanner.vala:738: Option 0: title='Number of options' type=int size=4 cap=soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Read-only option that specifies how many options a specific device supports.
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (1)
[+24,59s] DEBUG: scanner.vala:738: Option 1: name='standard' title='Standard' type=group size=4
[+24,59s] DEBUG: scanner.vala:741: Description: Source, mode and resolution options
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (2)
[+24,59s] DEBUG: scanner.vala:738: Option 2: name='resolution' title='Scan resolution' type=int size=4 unit=dpi values=[75, 100, 150, 200, 300, 600] cap=soft-select,soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Sets the resolution of the scanned image.
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (3)
[+24,59s] DEBUG: scanner.vala:738: Option 3: name='mode' title='Scan mode' type=string size=9 values=["Lineart", "Halftone", "Gray", "Color"] cap=soft-select,soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Selects the scan mode (e.g., lineart, monochrome, or color).
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (4)
[+24,59s] DEBUG: scanner.vala:738: Option 4: name='highlight' title='Threshold' type=fixed size=4 unit=percent min=30,000000, max=70,000000, quant=655360 cap=soft-select,soft-detect,inactive
[+24,59s] DEBUG: scanner.vala:741: Description: Select minimum-brightness to get a white point
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (5)
[+24,59s] DEBUG: scanner.vala:738: Option 5: name='source' title='Scan source' type=string size=8 values=["Flatbed", "ADF", "Auto"] cap=soft-select,soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Selects the scan source (such as a document-feeder).
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (6)
[+24,59s] DEBUG: scanner.vala:738: Option 6: name='geometry' title='Geometry' type=group size=4
[+24,59s] DEBUG: scanner.vala:741: Description: Scan area and media size options
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (7)
[+24,59s] DEBUG: scanner.vala:738: Option 7: name='tl-x' title='Top-left x' type=fixed size=4 unit=mm min=0,000000, max=216,069321, quant=65536 cap=soft-select,soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Top-left x position of scan area.
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (8)
[+24,59s] DEBUG: scanner.vala:738: Option 8: name='tl-y' title='Top-left y' type=fixed size=4 unit=mm min=0,000000, max=297,179993, quant=65536 cap=soft-select,soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Top-left y position of scan area.
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (9)
[+24,59s] DEBUG: scanner.vala:738: Option 9: name='br-x' title='Bottom-right x' type=fixed size=4 unit=mm min=0,000000, max=216,069321, quant=65536 cap=soft-select,soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Bottom-right x position of scan area.
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (10)
[+24,59s] DEBUG: scanner.vala:738: Option 10: name='br-y' title='Bottom-right y' type=fixed size=4 unit=mm min=0,000000, max=297,179993, quant=65536 cap=soft-select,soft-detect
[+24,59s] DEBUG: scanner.vala:741: Description: Bottom-right y position of scan area.
[+24,59s] DEBUG: scanner.vala:888: sane_get_option_descriptor (11)
[+24,59s] DEBUG: scanner.vala:549: sane_control_option (5, SANE_ACTION_SET_VALUE, "Auto") -> (SANE_STATUS_GOOD, "Auto")
[+24,59s] DEBUG: scanner.vala:549: sane_control_option (3, SANE_ACTION_SET_VALUE, "Color") -> (SANE_STATUS_GOOD, "Color")
[+24,59s] DEBUG: scanner.vala:465: sane_control_option (2, SANE_ACTION_SET_VALUE, 150) -> (SANE_STATUS_GOOD, 150)
[+24,59s] DEBUG: scanner.vala:533: sane_control_option (9, SANE_ACTION_SET_VALUE, option.range.max) -> (SANE_STATUS_GOOD)
[+24,59s] DEBUG: scanner.vala:533: sane_control_option (10, SANE_ACTION_SET_VALUE, option.range.max) -> (SANE_STATUS_GOOD)
[+24,70s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+29,40s] DEBUG: scanner.vala:1217: sane_start (page=0, pass=0) -> SANE_STATUS_GOOD
[+29,40s] DEBUG: scanner.vala:1234: sane_get_parameters () -> SANE_STATUS_GOOD
[+29,40s] DEBUG: scanner.vala:1246: Parameters: format=SANE_FRAME_RGB last_frame=SANE_TRUE bytes_per_line=0 pixels_per_line=0 lines=1734 depth=8
[+29,40s] DEBUG: scanner.vala:1321: sane_read (1) -> (SANE_STATUS_IO_ERROR, 0)
[+29,40s] WARNING: scanner.vala:1337: Unable to read frame from device: Error during device I/O
[+29,40s] DEBUG: scanner.vala:768: sane_cancel ()
[+29,40s] DEBUG: scanner.vala:771: sane_close ()
[+29,41s] DEBUG: simple-scan.vala:349: Page is 0 pixels wide, 1734 pixels high, 8 bits per pixel
[+29,41s] CRITICAL: page_set_page_info: assertion '_tmp14_ != NULL' failed
[+29,41s] DEBUG: simple-scan.vala:283: Getting color profile for device xerox_mfp:libusb:003:004
[+29,41s] DEBUG: scanner.vala:1521: Requesting redetection of scan devices
[+29,41s] DEBUG: 3:4 does not exist
[+29,41s] DEBUG: scanner.vala:806: Processing request
[+29,55s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+34,89s] DEBUG: simple-scan.vala:303: Unable to find colord device xerox_mfp:libusb:003:004: The name org.freedesktop.ColorManager was not provided by any .service files
[+35,04s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+37,88s] DEBUG: scanner.vala:341: sane_get_devices () -> SANE_STATUS_GOOD
[+37,88s] DEBUG: scanner.vala:353: Device: name="xerox_mfp:libusb:003:004" vendor="Samsung" model="M2070 Series" type="multi-function peripheral"
[+37,98s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+38,24s] DEBUG: scanner.vala:1521: Requesting redetection of scan devices
[+38,25s] DEBUG: scanner.vala:806: Processing request
[+47,32s] DEBUG: scanner.vala:341: sane_get_devices () -> SANE_STATUS_GOOD
[+47,32s] DEBUG: scanner.vala:353: Device: name="xerox_mfp:libusb:003:004" vendor="Samsung" model="M2070 Series" type="multi-function peripheral"
[+47,42s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+50,88s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+50,99s] DEBUG: app-window.vala:1775: Saving state to /home/czeman/.cache/simple-scan/state
[+52,42s] DEBUG: autosave-manager.vala:195: Deleting autosave records
[+52,43s] DEBUG: scanner.vala:1597: Stopping scan thread
[+52,43s] DEBUG: scanner.vala:806: Processing request
[+52,43s] DEBUG: scanner.vala:1608: sane_exit ()