US 6,546,220 B1 · Image forming apparatus with plural color image forming units moveable into image forming position · patentgrep

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Abstract

An image forming apparatus includes a plurality of image forming units having a developer, a charger, and a photosensitive member; a carriage for retaining the plurality of image forming units so that they can be removed and installed, and which rotates the plurality of image forming units between an image forming position and other positions; a laser exposing device for exposing the photosensitive member at an image forming position; an intermediate transfer belt for accepting a toner image formed on the photosensitive member at the image forming position, and forming a color image; an output shaft for coupling with at least one axis end portion of the photosensitive member in the image forming position in the axial direction of the photosensitive member, and positioning the photosensitive member at a proper position; a rotation stop portion for positioning the rotation orientation of the image forming units with respect to the axis of the photosensitive members; and a retransfer roller for transferring the color image formed on the intermediate transfer belt at a retransfer position onto recording paper. Thus, it is possible to retain the image forming unit precisely and reliably at a proper position.

Claims57

Dependent claims

An image forming apparatus, comprising:

a plurality of image forming units having a rotator,
image forming unit conveying means for switching said plurality of image forming units by moving them successively between an image forming position and a waiting position;
a rotator support member for positioning the rotator that is in the image forming position into a proper position in an apparatus main body by coupling with at least one axial end portion of said rotator in an axial direction of said rotator and supporting said image forming units in a freely rotatable manner;
and
a rotation stop portion for positioning a rotational orientation of an axis of said rotator of said image forming units,
wherein said rotation stop portion stops the rotation of said image forming units on a surface that is substantially parallel to a line connecting the axis of said rotator and a rotation stop position.

3 more elements

An image forming apparatus, comprising:

a plurality of image forming units having a rotator with flanges on both ends;
a unit retaining member, which retains said plurality of image forming units, and switches said plurality of image forming units by moving them successively between an image forming position and a waiting position;
an intermediate transfer member, which contacts the image forming unit positioned in the image forming position and successively accepts toner images of various colors from said image forming units, so as to form a colored toner image on its surface;
and
a positioning member for coupling with at least one of said flanges of said rotator by advancing and receding in an axial direction when being substantially coaxial with said rotator of the image forming unit that is positioned in the image forming position;
wherein a coupling part for coupling with said positioning member is provided at the center of end surfaces of said flanges;
wherein said coupling part is a concave tapered surface with a circular cross section having the axis of said rotator as a center axis;
a tip of said positioning member is a convex spherical surface, whose rotation center is the center axis.

5 more elements

An image forming apparatus, comprising:

a plurality of image forming units having a rotator with flanges on both ends;
a unit retaining member, which retains said plurality of image forming units, and switches said plurality of image forming units by moving them successively between an image forming position and a waiting position;
an intermediate transfer member, which contacts the image forming unit positioned in the image forming position and successively accepts toner images of various colors from said image forming units, so as to form a colored toner image on its surface;
a positioning member for coupling at a coupling part at a center of an end surface of at least one of said flanges of said rotator by advancing and receding in an axial direction when being substantially coaxial with said rotator of the image forming unit that is positioned in the image forming position;
a driving motor for generating a rotation force for said rotator;
and
a rotation transmission member provided in one piece with one positioning member, for which transmission and disconnection of the rotation force is performed by substantially coaxial rotation with the rotator that is positioned in the image forming position, and advancing and receding in the axial direction of said rotator;
wherein an end surface of the flange opposing said rotation transmission member is provided with rotation follower portions made of a plurality of concave and convex portions;
and
wherein said rotation transmission member is provided with one transmission tongue for transmitting a rotation force by meshing with said rotation follower portions.

7 more elements

An image forming apparatus, comprising:

a plurality of image forming units having a rotator with flanges on both ends;
a unit retaining member, which retains said plurality of image forming units, and switches said plurality of image forming units by moving them successively between an image forming position and a waiting position;
an intermediate transfer member, which contacts the image forming unit positioned in the image forming position and successively accepts toner images of various colors from said image forming units, so as to form a colored toner image on its surface;
a positioning member for coupling at a coupling part at a center of an end surface of at least one of said flanges of said rotator by advancing and receding in an axial direction when being substantially coaxial with said rotator of the image forming unit that is positioned in the image forming position;
a driving motor for generating a rotation force for said rotator;
and
a rotation transmission member provided in one piece with one positioning member, for which transmission and disconnection of the rotation force is performed by substantially coaxial rotation with the rotator that is positioned in the image forming position, and advancing and receding in the axial direction of said rotator;
wherein an end surface of the flange opposing said rotation transmission member is provided with rotation follower portions made of a plurality of concave and convex portions;
wherein said rotation transmission member is provided with a transmission tongue for transmitting a rotation force by meshing with said rotation follower portions;
and
wherein, when a tip of said transmission tongue reaches a tip position of said rotation follower portions during the transition from a disconnected state to a connected state of the rotation force, said positioning member has advanced inside beyond an edge portion of the coupling part.

8 more elements

An image forming apparatus, comprising:

a plurality of image forming units having a rotator with flanges on both ends;
a unit retaining member, which retains said plurality of image forming units, and switches said plurality of image forming units by moving them successively between an image forming position and a waiting position;
an intermediate transfer member, which contacts the image forming unit positioned in the image forming position and successively accepts toner images of various colors from said image forming units, so as to form a colored toner image on its surface;
a driving motor for generating a rotation force for said rotator and said intermediate transfer member, which stops when said unit retaining member is being moved;
a detection means for detecting a reference position of said intermediate transfer member after said driving motor has started;
an exposure means for forming a latent image on said rotator, based on a detection signal from said detection means;
a rotation transmission member for which transmission and disconnection of the rotation force is performed by substantially coaxial rotation with the rotator that is positioned in the image forming position, and advancing and receding in the axial direction of said photosensitive member;
wherein an end surface of one of said flanges is provided in circumferential direction with rotation follower portions made of a plurality of concave and convex portions, which transmit a rotation force by meshing with said rotation transmission member;
wherein a pitch between neighboring concave and concave portions of said rotation follower portions is smaller than a rotation angle of said driving transmission member from the start of said driving motor until the generation of the detection signal.

6 more elements

An image forming unit comprising a rotator with flanges on both ends, which can be installed in and removed from an image forming apparatus comprising:

a unit retaining member, which retains a plurality of image forming units, and switches said plurality of image forming units by moving them successively between an image forming position and a waiting position;
an intermediate transfer member, which contacts the image forming unit positioned in the image forming position and successively accepts toner images of various colors from said image forming units, so as to form a colored toner image on its surface;
and
a positioning member for coupling with at least one of said flanges of said rotator by advancing and receding in the axial direction when being substantially coaxial with said rotator of the image forming unit that is positioned in the image forming position, the tip of the positioning member being a convex spherical surface whose rotation center is the center axis;
wherein a coupling part for coupling with said positioning member of said image forming apparatus is provided at the center of an end surface of said flanges;
and
wherein said coupling part is a concave tapered surface with a circular cross section having the axis of said rotator as a center axis.

4 more elements

An image forming unit comprising a rotator with flanges on both ends, which can be installed in and removed from an image forming apparatus comprising:

a unit retaining member, which retains a plurality of image forming units, and switches said plurality of image forming units by moving them successively between an image forming position and a waiting position;
an intermediate transfer member, which contacts the image forming unit positioned in the image forming position and successively accepts toner images of various colors from said image forming units, so as to form a colored toner image on its surface;
a positioning member for coupling with at least one of said flanges of said rotator by advancing and receding in an axial direction when being substantially coaxial with said rotator of the image forming unit that is positioned in the image forming position;
a driving motor for generating a rotation force for said rotator;
and
a rotation transmission member provided in one piece with one positioning member, and which has a transmission tongue for performing transmission and disconnection of the rotation force by substantially coaxial rotation with the rotator that is positioned in the image forming position, and advancing and receding in an axial direction of said rotator;
wherein a coupling part for coupling with the positioning member of the image forming apparatus is provided at the center of an end surface of said flanges;
wherein an end surface of the flange that opposes the rotation transmission member is provided with rotation follower portions made of a plurality of concave and convex portions;
and
wherein, when a tip of said transmission tongue reaches a tip position of said rotation follower portions during the transition from a disconnected state to a transmission state of the rotation force, said positioning member has advanced inside beyond an edge portion of said coupling part.

7 more elements

An image forming unit comprising a rotator with flanges on both ends, which can be installed in and removed from an image forming apparatus comprising:

a unit retaining member, which retains said plurality of image forming units, and switches said plurality of image forming units by moving them successively between an image forming position and a waiting position;
an intermediate transfer member, which contacts the image forming unit positioned in the image forming position and successively accepts toner images of various colors from said image forming units, so as to form a colored toner image on its surface;
a driving motor for generating a rotation force for said rotator and said intermediate transfer member, which stops when said unit retaining member is being moved;
a detection means for detecting a reference position of said intermediate transfer member after said driving motor has started;
an exposure means for forming a latent image on said image forming unit, based on a detection signal from said detection means;
a rotation transmission member for which transmission and disconnection of the rotation force is performed by substantially coaxial rotation with the rotator that is positioned in the image forming position, and advancing and receding in the axial direction of said photosensitive member;
wherein an end surface of one of said flanges is provided in circumferential direction with rotation follower portions made of a plurality of concave and convex portions, which transmit a rotation force by meshing with said rotation transmission member;
wherein a pitch between neighboring concave and concave portions of said rotation follower portions is smaller than a rotation angle of said driving transmission member from the start of said driving motor until the generation of the detection signal.

5 more elements

Dependencies are inferred from the claim text.