Image scanning unit and image forming apparatus having the same

Abstract

An image scanning unit an image forming apparatus having the same to scan an image recorded on a document. The image scanning unit includes: a transparent window on which a document to be scanned is laid; an image sensor running straightly under the transparent window for capturing an image recorded on the document, a unit for driving the image sensor; a guide shaft for guiding the straight movement of the image sensor; and an image sensor carrier connected to the driving unit and the guide shaft for straightly moving the image sensor along the guide shaft when the driving unit operates. The image sensor carrier has an image sensor mounting surface on which the image sensor is mounted, and a guide shaft holder integrally formed with the image sensor mounting surface and mounted on the guide shaft.

What is claimed is: 
     
       1. An image scanning device for use in an image forming apparatus which includes a guide shaft to control a motion of the image scanning device, comprising:
 a carriage including an integrally formed channel having a substantially semi-circular shape and a plurality of friction reducing protrusions spaced intermittently around a diameter of the guide shaft to engage the guide shaft and wherein the channel is formed of a rigid material, the channel includes first and second friction reducing protrusions formed as first and second planar faces engaging the guide shaft at 180 degree intervals along the diameter of the guide shaft and the first and second planar faces are substantially parallel to each other and the channel further includes a third friction reducing protrusion formed as a third planar face engaging the guide shaft, the third planar face extending from one of the first and second planar faces at an incline in a direction non-perpendicular to the first and second planar faces, the channel further including a non-planar face which does not engage the guide shaft, the non-planar face extending at one end from the third planar face and being spaced apart from the guide shaft; 
 an image sensor detachably mounted on the carriage; and 
 a driver to linearly move the carriage and the image sensor along the guide shaft. 
 
     
     
       2. The image scanning device according to  claim 1 , wherein the driver comprises a motor driving a belt extending in parallel with respect to the guide shaft, and the carriage includes a belt grasper engaging the belt such that when the belt is driven the carriage is linearly moved by the belt. 
     
     
       3. The image scanning device according to  claim 1 , further comprising a coupler to attach the image sensor to the carriage, in which the coupler includes a positioning boss formed on the image sensor, and a bracket provided on the carriage to receive the positioning boss. 
     
     
       4. The image scanning device according to  claim 1 , further comprising a coupler to attach the image sensor to the carriage, in which the coupler includes a positioning boss formed on the carriage, and a notch formed on the image sensor to receive the positioning boss. 
     
     
       5. The image scanning device according to  claim 1 , wherein the carriage is formed of a polymer resin through molding. 
     
     
       6. The image scanning device according to  claim 1 , wherein the carriage further comprises a tensioner to bias the image sensor against a transparent work surface of the image forming apparatus. 
     
     
       7. An image scanning device for use in an image forming apparatus which includes a guide shaft to control a motion of the image scanning device, comprising:
 a non-metallic carriage including an integrally formed channel having a substantially semi-circular shape and a plurality of friction reducing protrusions spaced intermittently around a diameter of the guide shaft to engage the guide shaft and wherein the channel is formed of a rigid material, the channel includes first and second friction reducing protrusions formed as first and second planar faces engaging the guide shaft at 180 degree intervals along the diameter of the guide shaft and the first and second planar faces are substantially parallel to each other and the channel further includes a third friction reducing protrusion formed as a third planar face engaging the guide shaft, the third planar face extending from one of the first and second planar faces at an incline in a direction non-perpendicular to the first and second planar faces, the channel further including a non-planar face which does not engage the guide shaft, the non-planar face extending at one end from the third planar face and being spaced apart from the guide shaft; 
 an image sensor detachably mounted on the non-metallic carriage; and 
 a driver to linearly move the non-metallic carriage and the image sensor along the guide shaft. 
 
     
     
       8. The image scanning device according to  claim 7 , wherein the non-metallic carriage is formed of a polymer resin through molding. 
     
     
       9. The image scanning device according to  claim 8 , wherein the driver comprises a motor driving a belt extending in parallel with respect to the guide shaft, and the carriage includes a belt grasper engaging the belt such that when the belt is driven the carriage is linearly moved by the belt. 
     
     
       10. An image scanning device for use in an image forming apparatus which includes a guide shaft to control a motion of the image scanning device, comprising:
 a carriage including an integrally formed channel having a plurality of portions spaced intermittently around a diameter of the guide shaft to intermittently engage the guide shaft, wherein the channel is formed of a rigid material and the plurality of portions include:
 first and second portions, formed as first and second planar faces substantially parallel to each other, to engage the guide shaft at 180 degree intervals along the diameter of the guide shaft, and 
 a third portion, formed as a third planar face which extends from one of the first and second planar faces at an incline in a direction non-perpendicular to the first and second planar faces, to engage the guide shaft, 
   wherein the channel further includes a non-planar face which does not engage the guide shaft, the non-planar face extending at one end from the third planar face and being spaced apart from the guide shaft;   an image sensor detachably mounted on the carriage; and   a driver to linearly move the carriage and the image sensor along the guide shaft.   
     
     
       11. The image scanning device according to claim 10, wherein the third portion is between the first and second portions. 
     
     
       12. The image scanning device according to claim 11, wherein the channel includes a first part spaced apart from the guide shaft between the first portion and the third portion. 
     
     
       13. The image scanning device according to claim 11, wherein the channel includes a second part spaced apart from the guide shaft between the second portion and the third portion. 
     
     
       14. The image scanning device according to claim 11, wherein the channel includes at least two parts that are spaced apart from the guide shaft between the first portion and the second portion. 
     
     
       15. An image scanning device, comprising:
 a guide shaft;   a carriage including an integrally formed channel having a plurality of portions spaced intermittently around a diameter of the guide shaft to intermittently engage the guide shaft, the plurality of portions including:
 first and second portions, formed as first and second planar faces substantially parallel to each other, to engage the guide shaft at 180 degree intervals along the diameter of the guide shaft, and 
 third and fourth portions, formed as third and fourth planar faces and separated by a part of the channel that does not engage the guide shaft, to engage the guide shaft, 
   wherein the channel further includes a fifth portion having a non-planar face which does not engage the guide shaft, the non-planar face extending at one end from the third planar face and extending at another end from the fourth planar face, and being spaced apart from the guide shaft;   an image sensor mounted on the carriage; and   a driver to move the carriage and the image sensor along the guide shaft.   
     
     
       16. The image scanning device according to claim 15, wherein the third and fourth portions are between the first and second portions. 
     
     
       17. The image scanning device according to claim 16, wherein the channel includes a first part spaced apart from the guide shaft between the first portion and the third portion. 
     
     
       18. The image scanning device according to claim 16, wherein the channel includes a second part spaced apart from the guide shaft between the second portion and the fourth portion. 
     
     
       19. The image scanning device according to claim 15, wherein the first and second portions, formed as the first and second planar faces, extend in a direction away from the part of the channel that does not engage the guide shaft beyond a center of the guide shaft. 
     
     
       20. The image scanning device according to claim 15, wherein the non-planar face is an arc-shaped face.