I'm getting the same shocks every time I touch the keyboard on my SP-540v (only happens this time of year), I don't know if it's me building up the charge as I walk over to the printer or if it's the printer that has built up the static charge. I have been worried that if it's me building up the charge, and I touch the keypad I may damage the printer in some way.
So, I was thinking of getting an anti-static floor mat to put in front of the printer, which has a ground wire that you attach to some electrical grounded source, they when I stand on the mat any charge on me would be dissipated.
I worked at Texas Instruments for 17 years and they used anti-static floor mats everywhere in front of all kinds of machines, the mats worked great however you needed to wear special static conductive shoes (which the company paid for), or attach a conductive heel strip to you regular shoes with a strap from inside you socks (touching your skin) down to the bottom of your shoe. That way any static built up on you as your polyester clothing rubbed together while moving or walking would be dissipated through the shoe to the mate and when you touched the metal machine there was NO shock.