Color image-forming apparatus adapted to stabilize contact between endless belt-like photosensitive medium and developing roller

A color image-forming apparatus comprising:

• an endless belt-like photosensitive member stretched between and wound around a plurality of support rollers;
• a plurality of developing devices spaced at equal intervals from one another along a flat surface portion of said photosensitive member extending between said support rollers, said plurality of developing devices including two opposite outer developing devices, each of said developing devices including a developing roller carrying a developing material, and causing said developing roller to make contact with an outer surface of said flat surface portion of said photosensitive member to apply said developing material thereto to thereby effect developing;
• and
• a plurality of support members each opposed to an intermediate point between each of adjacent ones of said developing devices, said support members being laid in parallel with said support rollers, and held in contact with an inner surface of said photosensitive member;
• and
• two outer support members held in contact with the inner surface of said photosensitive member, one of said two outer support members being located between a position of contact of said developing roller of one of said two opposite outer developing devices with said photosensitive member and a position of contact of said support roller, closest to said one of said two opposite outer developing devices, with said photosensitive member whereas the other one of said two outer support members is located between a position of contact of said developing roller of the other one of said two opposite outer developing devices with said photosensitive member and a position of contact of said support roller, closest to said other one of said two opposite outer developing devices, with said photosensitive member, and the distance between the position of contact of said developing roller of each of said two opposite outer developing devices with said photosensitive member and the position of contact of each of said two outer support members, closest to the associated one of said two opposite outer developing devices, with the photosensitive member, being substantially equal to the distance between a position of contact of said developing roller of each of said developing devices, other than said two opposite outer developing devices, with said photosensitive member and a position of contact of a respective one of said plurality of said support members, closest to said associated developing device, with said photosensitive member.