{TAIL ~ The photoconductor unit} 7, wherein the grid electrode extends in a long side direction that is orthogonal to {HEAD ~ the short side direction}, and the grid electrode has different thicknesses in a thickness direction that is orthogonal to the long side direction and the short side direction 
{ TAIL ~ The photoconductor unit } 7 , wherein the grid electrode extends in a long side direction that is orthogonal to { HEAD ~ the short side direction } , and the grid electrode has different thicknesses in a thickness direction that is orthogonal to the long side direction and the short side direction
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH