Driving device for a document platen and copying machine incorporating a movable document platen

A driving device for a document platen, comprising:

• a reciprocating document platen on which a document is placed;
• driving means for producing a driving force;
• an input gear located in a fixed position for transmitting the driving force;
• a planetary gear which meshes with and moves around said input gear;
• a connecting plate attached rotatably to said input gear and said planetary gear;
• and
• an endless gear, connected to said document platen, and having internal teeth, for converting a rotation of said input gear into a reciprocating movement of said document platen through said planetary gear, the teeth of said input gear facing the teeth of said planetary gear,
• wherein said connecting plate is positioned so as to maintain said planetary gear and said input gear and endless gear in mesh, and wherein said endless gear includes two rack sections, and two semicircular gear sections for connecting the ends of one of said two rack sections with those of said other rack section, a pitch line of said internal teeth at said one rack section being parallel with a pitch line of said internal teeth at said other rack sections, said internal teeth being aligned in an arc at said semicircular gear sections.

A copying machine comprising:

• a movable document platen on which a document is placed;
• a driving device for reciprocating said document platen;
• transport means for transporting copy paper on which an image is to be copied when said document platen is moved;
• and
• driving means for driving both said driving device and said transport means,
• wherein a transport distance of the copy paper is set according to a travel distance of said document platen such that said transport means transports the copy paper having a copied image thereon to be fed out of said copying machine before said document platen which has been moved to scan the document returns to a predetermined original position;
• wherein said driving device comprises:
• a second driving means for producing a driving force;
• an input gear, located in a fixed position, to which the driving force if transmitted;
• a planetary gear which meshes with and moves around said input gear;
• and
• an endless gear in the form of a closed loop, wherein said endless gear is connected to said document platen and has internal teeth which mesh with said planetary gear such that a reciprocating movement of said document platen is caused by a circular movement of said planetary gear around said input gear.

A copying machine, comprising:

• driving means for producing a driving force;
• a movable document platen on which a document is placed;
• a main body on which said document platen is installed;
• and
• a driving device for reciprocating said document platen on said main body, wherein said driving device includes;
• an input gear to which the driving force is transmitted, said input gear being located in a fixed position such that the rotating axis of said input gear is substantially parallel with said document platen;
• a planetary gear which meshes with and moves around said input gear;
• and
• an endless gear having internal teeth which mesh with said planetary gear, wherein said endless gear is in the form of a closed loop, located on and connected to a side of said document platen, and wherein a circular movement of said planetary gear around said input gear causes a reciprocating movement of said document platen.

A copying machine, comprising:

• driving means for producing a driving force;
• a movable document platen on which a document is placed;
• a driving force transmitting mechanism for transmitting the driving force to said document platen;
• and
• an overload release mechanism for suspending the supplying of the driving force to said document platen by using an overload which prevents a movement of said document platen.

A driving device for a document platen, comprising:

• a reciprocating document platen on which a document is placed;
• driving means for producing a driving force;
• an input gear, located in a fixed position, for transmitting the driving force;
• a planetary gear which meshes with and moves around said input gear;
• a connecting plate for rotatably supporting said input gear and said planetary gear;
• and
• an endless gear, connected to said document platen and having internal teeth, for converting a rotation of said input gear into a reciprocating movement of said document platen through said planetary gear,
• wherein said endless gear includes two rack sections, two semicircular gear sections for connecting the ends of one of said two rack sections with those of said other rack section, a sliding surface being formed around the outer circumference thereof, a pitch line of said internal teeth at said one rack section being parallel with a pitch line of said internal teeth at said other rack section, said internal teeth being aligned in an arc at said semicircular gear sections,
• wherein said connecting plate has a sliding section on an edge thereof and is positioned so as to maintain said planetary gear and said input gear and endless gear are in mesh, said sliding section sliding over said sliding surface,
• wherein said sliding section includes a pair of sliding bodies aligned along a moving direction of said endless gear, said sliding bodies being disposed such that, when said sliding bodies and a shaft of said input gear are connected to each other with imaginary straight lines, an isosceles triangle with the imaginary line between said sliding bodies a base is formed.

A driving device for a document platen, comprising:

• a reciprocating document platen on which a document is placed;
• driving means for producing a driving force;
• an input gear, located in a fixed position, for transmitting the driving force;
• a planetary gear which meshes with and moves around said input gear;
• a connecting plate for rotatably supporting said input gear and said planetary gear;
• an endless gear, connected to said document platen, for converting a rotation of said input gear into a reciprocating movement of said document platen through said planetary gear;
• and
• a driving force transmitting mechanism for transmitting the driving force of said input gear to said document platen, said driving force transmitting mechanism including an overload release mechanism for suspending the supplying of the driving force to said document platen by using an overload which prevents a movement of said document platen.