Development apparatus having an adjustable width development nip

A development unit for developing a latent image recorded on an image bearing member, the development unit comprising:

• (a) a housing storing a supply of magnetizable two-component developer material containing toner particles;
• (b) means mounted within said housing for moving developer material thereabout;
• and
• (c) a toner transport assembly including:
• (i) a movable belt donor member forming a development nip with the image bearing member and transporting toner particles into and through said development nip for latent image development;
• (ii) a contoured back supporting plate located across said development nip for spacing said belt donor member from the image bearing member;
• and
• (iii) first and second back up rollers mounted for training a portion of said belt donor member across a width of said development nip, said second back up roller being movable relative to said first back up roller to vary said width of said development nip.

A color reproduction machine including:

• (a) an image bearing member;
• (b) means for electrostatically recording a first and at least a second latent images on said image bearing member;
• and
• (c) a plurality of development units each storing developer material containing a different type of toner for developing said latent images on the image bearing member, said plurality of development units including:
• (i) a first development unit containing a first type of toner for developing said first latent image, said first development unit having a movable first belt donor member forming a first development nip with the image bearing member and a first set of back up rollers defining a first width of said first development nip;
• and
• (ii) a second development unit containing a second and different type of toner for developing said at least second latent images, said second development unit having a second belt donor member forming a second development nip with the image bearing member and a second set of back up rollers defining a second width for said second development nip, and said second width of said second development nip being unequal to said first width of said first development nip.