Vibrating device and image equipment having the same

An image equipment comprising:

• an image forming element having an image surface on which an optical image is formed;
• a dust-screening member which is shaped like a plate as a whole and has a light-transmitting region flaring in a radial direction from the center, facing the image surface and spaced therefrom by a predetermined distance;
• a sealing structure configured to surround the image forming element and the dust-screening member, thereby providing a closed space in which the image forming element and the dust-screening member that face each other;
• a first vibrating member arranged on the dust-screening member and outside the light-transmitting region through which a light beam for forming an optical image on the image surface passes, and configured to cause, when driven alone, the dust-screening member to undergo first standing-wave vibration;
• and
• a second vibrating member arranged on the dust-screening member and outside the light-transmitting region, not overlapping the first vibrating member, and configured to cause, when driven alone, the dust-screening member to undergo second standing-wave vibration, wherein
• the first vibrating member and the second vibrating member are so positioned that the first standing-wave vibration and second standing-wave vibration produced by the first and second vibrating members, respectively, overlap each other, thus producing a travelling wave propagating in one direction and having node regions at an outer circumferential edge of the dust-screening member, the node regions having virtually no vibrational amplitude.