HP OfficeJet Pro 9135e Wireless All-in-One Color Printer, Instant Ink; Two-sided printingHP OfficeJet Pro 9135e Wireless All-in-One Color Printer, Instant Ink; Two-sided printing. Print technology: Thermal inkjet, Printing: Colour printing, Maximum resolution: 4800 x 1200 DPI, Print speed (colour, normal quality, A4/US Letter): 20 ppm. Copying: Colour copying, Maximum copy resolution: 600 x 600 DPI. Scanning: Colour scanning, Optical scanning resolution: 1200 x 1200 DPI. Faxing: Colour faxing. Duplex functions: Print, Fax. Maximum ISO A-series paper size: A4. Wi-Fi. Direct printing. Product colour: GreyPrintingPrint technologyThermal inkjetPrintingColour printingDuplex printingYesDuplex printing modeAutoMaximum resolution4800 x 1200 DPIPrint resolution colour4800 x 1200 DPIPrint resolution black1200 x 1200 DPIPrint speed (black, normal quality, A4/US Letter)25 ppmPrint speed (colour, normal quality, A4/US Letter)20 ppmPrint speed (black, draft quality, A4/US Letter)39 ppmPrint speed 0