Hi, On Tue, Aug 30, 2022 at 10:36 PM Sean Greenslade <[email protected]> wrote:
> Hi, all. I recently picked up an Epson ES-50 sheet-feed scanner. My > intent is to use it for receipt scanning, so I tried it out with a > ~700 mm long receipt and found that it would error out at around 450 mm > into the scan. The manual claims the scanner is capable of a max of 72 > inch document length, so I started poking around in the epsonds backend > code. Something that jumped out at me was the eds_set_adf_area > function. It seems that for this particular scanner, three ADF size > values are reported: AREA, AMIN, and AMAX (in epsonds-cmd.c around line > 445 on current git master). The eds_set_adf_area function is called with > the values from AREA, which limits the document length to 14 inches. I'm > assuming AREA is just meant to be a default value, but if anyone has any > deeper insight into the meaning, I'd be interested to know. > Looking at that code, AMIN and AMAX are pretty much ignored. What do you get for all of the AREA/AMIN/AMAX parameters? Perhaps we can figure out what they mean and code up something a little better? > > The AMAX values reported seemed to match the manual's reported 72-inch > maximum, so on a whim, I just moved the eds_set_adf_area call to the > AMAX section. After recompiling, I was able to scan my long receipt no > problem. > > Now I'm wondering if there is any downside to using the max ADF size? If > not, would you consider the attached patch? > > I don't believe that we have a current maintainer for this backend although we do get some submissions from Epson Japan now and then for new models. I wonder if they would be willing to shed some light on this or provide us some documentation on this aspect of the protocol? Cheers, Ralph
