Sheet feeder and image forming apparatus having the same

Abstract

A device for supplying sheets including a main body; a sheet feed cassette; a lift plate; a lift plate lifter mechanism; and a drive device for the mechanism; in which a lift side coupling gear is engaged with a drive side coupling gear of the drive device when the sheet feed cassette is stored in the main body, and is displaceably supported in a direction of toward and away from with respect to the drive side coupling gear in a range where the engagement of the gears is not released.

1 . A device for supplying sheets, comprising:
 a sheet feed cassette in which sheets are stacked, and which can be pulled out and stored in a direction parallel to a sheet conveying direction with respect to a main body of an apparatus;   a lift plate which is located within the sheet feed cassette, and which has a top surface on which the sheets are placed;   a lift plate lifter mechanism which is located in the sheet feed cassette, for moving up the lift plate to displace the lift plate to a sheet supply position;   a drive device which is located in the main body of the apparatus, for providing power to the lift plate lifter mechanism;   the drive device comprises a drive side coupling gear that is coupled with the lift plate lifter mechanism when the sheet feed cassette is stored in the apparatus main body; and   the lift plate lifter mechanism comprises a lift side coupling gear which is located at a side surface of the sheet feed cassette, engaged with the drive side coupling gear of the drive device when the sheet feed cassette is stored in the main body, and is moveably supported in a direction toward and away from with respect to the drive side coupling gear in a range wherein the engagement of the gears is not released.   
     
     
         2 . A device for supplying sheets according to  claim 1 , wherein the sheet feed cassette has an elongated hole on a support portion of the lift side coupling gear, the elongated hole being capable of displacing the lift side coupling gear in a direction toward and away from with respect to the drive side coupling gear. 
     
     
         3 . A device for supplying sheets according to  claim 2 , wherein the elongated hole extends in the direction that the lift side coupling gear separates from the drive side coupling gear while rotating when the lift side coupling gear and the drive side coupling gear come in contact with each other. 
     
     
         4 . A device for supplying sheets according to  claim 1 , wherein, when the lift side coupling gear rotates, the lift side coupling gear is displaced in a direction toward the drive side coupling gear due to rotation force. 
     
     
         5 . An image forming apparatus, comprising:
 a device for supplying sheets comprising a sheet feed cassette in which sheets are stacked and which can be pulled out and stored in a direction parallel to a sheet conveying direction with respect to a main body of an apparatus;   a lift plate which is located within the sheet feed cassette, and which has a top surface on which the sheets are placed;   a lift plate lifter mechanism which is located in the sheet feed cassette, for moving up the lift plate to displace the lift plate to a sheet supply position;   a drive device which is located in the main body,   the drive device comprises a drive side coupling gear that is coupled with the lift plate lifter mechanism when the sheet feed cassette is stored in the main body; and   the lift plate lifter mechanism comprises a lift side coupling gear which is located at a side surface of the sheet feed cassette, engaged with the drive side coupling gear of the drive device when the sheet feed cassette is stored in the main body, and is displaceably supported in a direction of toward and away from with respect to the drive side coupling gear in a range where the engagement of the gears is not released.   
     
     
         6 . A device for supplying sheets, comprising:
 a sheet feed cassette in which sheets are stacked, and which can be pulled out and stored in a main body of an apparatus;   a lift plate which is located within the sheet feed cassette;   a lift plate lifter mechanism which is located in the sheet feed cassette, for moving up the lift plate to a sheet supply position;   a drive device which is located in the main body of the apparatus, for providing power to the lift plate lifter mechanism;   the drive device comprises a drive side coupling gear that is coupled with the lift plate lifter mechanism when the sheet feed cassette is stored in the apparatus main body; and   the lift plate lifter mechanism comprises a lift side coupling gear engaged with the drive side coupling gear of the drive device when the sheet feed cassette is stored in the main body, and is moveable toward and away from the drive side coupling gear without the engagement of the gears being released.