Image forming apparatus

An image forming apparatus, comprising:

• an image forming device to form an image on a surface of a sheet;
• a sheet feeding unit to feed the sheet to the image forming device, the sheet feeding unit including:
• an endless, dielectric belt disposed facing an upper surface of a sheet stack including an uppermost sheet of multiple sheets to contact and attract the uppermost sheet to a surface thereof and feed in a sheet feeding direction as the dielectric belt rotates;
• and
• an electric potential pattern forming unit to form an electric potential pattern on a surface of the dielectric belt having multiple potential holding sections of opposite polarities disposed adjacent to each other;
• a belt pressing member movably disposed in contact with an inner surface of a flat portion of the dielectric belt to press the dielectric belt outwardly, an outer surface of the flat portion of the dielectric belt facing and contacting the upper surface of the sheet stack;
• and
• a moving unit to move the belt pressing member between a sheet attracting position, at which an upstream part of the flat portion of the dielectric belt faces parallel to the upper surface of the sheet stack and a downstream part of the flat portion of the dielectric belt being non-parallel in relation to the upper surface of the sheet stack while being pressed outwardly by the belt pressing member, and a sheet feeding position, at which both the upstream and the downstream parts of the flat portion of the dielectric belt are configured in a flat, parallel manner,
• the upstream part of the flat portion of the dielectric belt attracting a leading area of the uppermost sheet at the sheet attracting position,
• the moving unit moving the belt pressing member to the sheet feeding position, and
• the flat portion of the dielectric belt feeding the uppermost sheet in the sheet feeding direction while carrying the uppermost sheet thereon as the dielectric belt rotates,
• the flat portion of the dielectric belt is tensioned by a first supporting member fixedly disposed to rotate the dielectric belt and a second supporting member movably disposed downstream from the first supporting member in the sheet feeding direction and rotated together with the first supporting member, and
• the second supporting member being moved towards the upstream part of the flat portion of the dielectric belt when the belt pressing member is in the sheet attracting position.