I have DotTwain working fine with single image capture, and the capture of multiple documents into individual images using the document feeder.

I'm struggling with loading multiple sheets into the document feeder and acquiring them as a multi page tiff. I'm finding that when I call acquire, the FileTransfer event is firing as per normal and I'm setting the file name. But then the cancel event is firing straight away, and not a murmur from the scanner.

When I call GetSupportedImageFormats() on the device, it returns Bmp and TiffMulti. Oddly it doesn't list Tiff. Acquisition works fine if I set the device's FileFormat to Tiff, but doesn't work at all if I set it to TiffMulti.

The device is a Brother MFC-7820N connected via USB.

I'm capturing directly to file, if that has any bearing.

If this isn't how one acquires multiple documents into a single multi page tiff, then pointers are appreciated.

Cheers,

BF

Sounds like you're doing everything correctly.  It might just be a bad driver.  Perhaps they meant to return Tiff as a supported format and made a mistake.

If you could create a trace log (http://www.atalasoft.com/KB/Article.aspx?id=10027) it might help us see why it's canceling.

Thanks Glenn, log attached. There's a bit of fluff in there from our app, just ignore it. :)

 Cheers,

BF

It looks like a driver issue.  When setting the file format before the scan it returns TWRC_SUCCESS, but when we ask it to perform the scan it returns TWRC_FAILURE / TWCC_BADVALUE.

In the FileTransfer event where you provide the filename, are you providing the format in e.FileFormat as well?  Make sure you are doing this.

I will say that if you can find a real TWAIN driver for this scanner, it's better to use it instead of a WIA driver.  WIA drivers are not fully compatible with TWAIN and TWAIN 2.0 no longer works with them.