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How to get back side of Duplex Scan

Greg Dec 03, 2012 03:00PM EST

I am evaluating the software to see if it will work for me. I am unable determine how to get the back side of a duplex scan. May scanner is a Xerox DocuMate 4440. It scans front and back in a single pass. I am able to scan fine and capture the front side of the document but can't access the other side. I can scan multiple pages using the TwainControl with the duplex setting checked, but only one side of each page appears to be saved. Is there a sample that will show me how to do this? Is it possible to do? Using the Windows 7 device under devices and printers, I have confirmed that I can manually get a duplex scan.


2 Data Techniques Responses and 1 Community Responses

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DTI Support  Data Techniques Employee Dec 03, 2012 03:08PM EST


With the ImageMan.Net Twain component you need to make sure the .Duplex property to Single_Pass then call the ScanPage method to acquire the pages until it returns null. If Duplex is enabled you could get the front page from the first ScanPage call then the backside on the 2nd call to ScanPage.

Thanks for your interest in our products and please let us know if you have any questions.

Data Techniques Support

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Greg  Data Techniques Employee Dec 03, 2012 03:41PM EST

I still just get one image. Here is the relevant code:

private void cmdScanNoUI_Click(object sender, EventArgs e)
System.Drawing.Image img;
imgs = new ArrayList();
twainControl1.MaxPages = 2;
twainControl1.UseDuplex = true;
twainControl1.Duplex = DTI.ImageMan.Twain.Duplexes.SinglePass;
twainControl1.ShowIndicators = false;
twainControl1.UserInterface = DTI.ImageMan.Twain.UserInterfaces.None;

img = twainControl1.ScanPage();
while (img != null)
img = twainControl1.ScanPage();

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DTI Support  Data Techniques Employee Dec 03, 2012 03:44PM EST

Hi Greg,

Can you add a call to twainControl1.InitializeLogging("c:\twain.log") at the top of your handler and then scan and email us the log file so we can see whats happening.

Also, make sure you have selected the native Twain version of the scanner driver and not the WIA flavor as WIA doesnt support Duplexing well.

You can email us the log at


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