Image forming apparatus having a plurality of developing means

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed;
• a plurality of developing means operable for development at different locations along a peripheral surface of said image bearing member to develop images on said image bearing member with toners of plural colors;
• and
• an intermediate transfer member onto which toner images of plural colors on said image bearing member are transferred, said intermediate transfer member being capable of bearing a plurality of toner images at different locations thereon with respective gaps therebetween, the toner images on said intermediate transfer member being transferred onto a transfer medium;
• wherein when a maximum length of respective gaps between adjacent ones of said plurality of developing means along the peripheral surface of said image bearing member is d, a peripheral velocity of said intermediate transfer member is u, and a peripheral velocity of said image bearing member is v, at least one of the respective gaps between adjacent ones of the plurality of toner images borne on said intermediate transfer member is greater than d.times.u/v.

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed;
• and
• a plurality of developing means operable for development at different locations along a peripheral surface of said image bearing member to superposition-develop images on said image bearing member with toners of plural colors, developed toner images of plural colors on said image bearing member being collectively transferred onto a transfer medium;
• wherein at least one of respective gaps between adjacent ones of the plurality of toner images borne on said image bearing member is greater than a maximum length .delta. of a gap between adjacent ones of said plurality of developing means along the peripheral surface of said image bearing member.

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed;
• first, second and third developing means for developing images on said image bearing member with toners of different colors, the order of operation of said first, second and third developing means being from a downstream one toward an upstream one with respect to the direction of movement of said image bearing member, and then from a most upstream one to a most downstream one with respect to the direction of movement of said image bearing member;
• and
• a transfer medium carrying member capable of carrying a transfer medium thereon and conveying the transfer medium to a transfer position a plurality of times, a plurality of toner images on said image bearing member being superposition-transferred onto a transfer medium carried on said transfer medium carrying member at said transfer position, said transfer medium carrying member being capable of carrying a plurality of transfer mediums at different locations thereon;
• wherein respective gaps between adjacent ones of the plurality of transfer mediums carried on said transfer medium carrying member include a first gap and a second gap larger than said first gap, and when an area of said image bearing member which corresponds to said second gap is at a developing position in advance, a developing operation is changed from said first developing means to said second developing means.

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed;
• first and second developing means for developing images on said image bearing member with toners of different colors;
• an intermediate transfer member on which toner images of plural colors on said image bearing member are superposed, said intermediate transfer member being capable of bearing a plurality of toner images at different locations thereon, with respective gaps therebetween, the toner images on said intermediate transfer member being transferred onto a transfer medium;
• wherein respective gaps between adjacent ones of the plurality of toner images borne on said intermediate transfer member include a first gap and a second gap larger than said first gap, and when an area of said image bearing member which corresponds to said second gap is at a developing position in advance, a developing operation is changed over from said first developing means to said second developing means.

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed;
• a plurality of developing means for developing images on said image bearing member with toners at a developing position, wherein plural developing means do not perform respective developing operations simultaneously at any time;
• and
• a transfer medium carrying member capable of carrying a transfer medium thereon and conveying the transfer medium to a transfer position a plurality of times, a plurality of toner images on said image bearing member being superposition-transferred onto a transfer medium carried on said transfer medium carrying member at said transfer position, said transfer medium carrying member being capable of carrying a plurality of transfer mediums at different locations thereon, respective gaps between adjacent ones of the plurality of transfer mediums carried on said transfer medium carrying member including a first gap and a second gap larger than said first gap,
• wherein when a length along a direction opposite a direction of movement of said image bearing member from an area on said image bearing member located at the developing position of said developing means upon completion of a developing operation by one of said plurality of developing means to an area on said image bearing member located at the developing position of said developing means upon start of a developing operation by another one of said plurality of developing means for performing a successive developing operation is defined as L.sub.1, a peripheral velocity of said transfer medium carrying member is defined as U, and a peripheral velocity of said image bearing member is defined as V, respectively, the second gap is larger than L.sub.1 .times.U/V.

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed;
• a plurality of developing means for developing images on said image bearing member with toners at a developing position, wherein said plurality of developing means do not perform respective developing operations simultaneously at any time;
• an intermediate transfer member on which a plurality of toner images on said image bearing member are superposed, said intermediate transfer member being capable of bearing a plurality of toner images at different locations thereon, with respective gaps therebetween, the toner images on said intermediate transfer member being transferred onto a transfer medium,
• wherein respective gaps between adjacent ones of the plurality of toner images borne on said intermediate transfer member include a first gap and a second gap larger than said first gap;
• wherein when a length along a direction opposite a direction of movement of said image bearing member from an area on said image bearing member located at a developing position of said developing means upon completion of a developing operation by one of said plurality of developing means to an area on said image bearing member located at a developing position of another one of said plurality of developing means upon start of a developing operation by said developing means performing a successive developing operation is defined as L.sub.2, a peripheral velocity of said intermediate transfer member is defined as u, and a peripheral velocity of said image bearing member is defined as v, respectively, the second gap is larger than L.sub.2 .times.u/v.

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed;
• a plurality of developing means operable for development at different locations along a peripheral surface of said image bearing member to develop images on said image bearing member with toners of plural colors, wherein the number of said plurality of developing means is greater than three, and the order of developing operations of said plurality of developing means is determined to be from a downstream one toward an upstream one with respect to a direction of movement of said image bearing member, and then from a most upstream one to a most downstream one with respect to the direction of movement of said image bearing member;
• a transfer medium carrying member for carrying a transfer medium thereon and conveying the transfer medium to a transfer position, developed toner images of plural colors on said image bearing member being superposition-transferred onto a transfer medium carried on said transfer medium carrying member, said transfer medium carrying member being capable of carrying a plurality of transfer mediums at different locations thereon,
• wherein respective gaps between adjacent ones of a plurality of transfer mediums carried on said transfer medium carrying member include a first gap and a second gap larger than said first gap;
• and
• wherein, when a maximum length of a gap between adjacent ones of said plurality of developing means along the peripheral surface of said image bearing member is D, a peripheral velocity of said transfer medium carrying member is U, and a peripheral velocity of said image bearing member is V, said second gap is greater than D.times.U/V.

An image forming apparatus comprising:

• a movable image bearing member for bearing images to be developed:
• a plurality of developing means operable for development at different locations along a peripheral surface of said image bearing member to develop images on said image bearing member with toners of plural colors, wherein the number of said plurality of developing means is greater than three, and the order of developing operations of said plurality of developing means is determined to be from a downstream one toward an upstream one with respect to a direction of movement of said image bearing member, and then from a most upstream one to a most downstream one with respect to the direction of movement of said image bearing member;
• an intermediate transfer member onto which toner images of plural colors on said image bearing member are superposition transferred, said intermediate transfer member being capable of bearing a plurality of toner images at different locations thereon, with respective gaps therebetween, the toner images on said intermediate transfer member being transferred onto a transfer medium, wherein respective gaps between adjacent ones of the plurality of toner images borne on said intermediate transfer member include a first gap and a second gap larger than said first gap;
• wherein when a maximum length of a gap between adjacent ones of said plurality of developing means along a peripheral surface said image bearing member is d, a peripheral velocity of said intermediate transfer member is u, and a peripheral velocity of said image bearing member is v, said second gap is greater than d.times.u/v.