IMAGE FORMING APPARATUS

Abstract

A multifunction apparatus includes a belt drive mechanism configured to move a carriage reciprocally placed on guide rails. The belt drive mechanism is comprised of a drive pulley, a driven pulley, and a timing belt, which is stretched between the drive pulley and the driven pulley. The carriage includes a belt holder, which is configured to hold the timing belt, and a torsion coil spring, which is configured to urge elastically the belt holder to the carriage. The belt holder is disposed in a position to urge the carriage to one of the guide rail, and movable toward the guide rail relative to the carriage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention now are described with reference to the accompanying drawings, which are given by way of example only, and are not intended to limit the present invention.

FIG. 1 is a perspective view of a multifunction apparatus according to an embodiment of the invention.

FIG. 2 is a cross-sectional view showing a structure of the multifunction apparatus.

FIG. 3 is an enlarged cross-sectional view showing components significant to the operation of a printer portion.

FIG. 4 is an enlarged plan view showing components significant to the operation of the printer portion.

FIG. 5 is an enlarged plan view showing a structure surrounding a driven pulley.

FIG. 6 is a bottom view of a recording head.

FIG. 7 is a block diagram showing the configuration of a control portion of the multifunction apparatus.

FIG. 8 is an enlarged plan view of a carriage.

FIG. 9 is a right side view of the carriage.

FIG. 10 is a cross-sectional view of the carriage taken along a line XI-XI of FIG. 8.

FIG. 11 is an exploded perspective view showing a sliding member, a coil spring, and a gap adjusting member.

FIG. 12 is a right side view of the carriage.

FIG. 13 is a cross-sectional view of the carriage taken along a line XI-XI of FIG. 8.

FIG. 14 is a right side view of the carriage.

FIG. 15 is cross-sectional view of the carriage taken along a line XI-XI of FIG. 8.

FIG. 16 is a perspective view showing a bottom surface of a carriage body.

FIG. 17 is an enlarged perspective view showing a structure of a holder receiving portion of a carriage body.

FIG. 18 is a perspective view of a belt holder.

FIG. 19 is an enlarged perspective view showing a structure around the holder receiving portion.

FIG. 20 is an enlarged cross-sectional view showing the belt holder of the carriage body and surrounding elements.

FIG. 21 is an enlarged cross-sectional view showing the belt holder of the carriage body and surrounding elements.

FIG. 22 is a partial bottom view of a carriage according to a modification of the invention.

FIG. 23 is a perspective view showing a rotating shaft and a slider.

FIG. 24 is a perspective view showing the rotating shaft.

FIG. 25 is a cross-sectional view of the rotating shaft and the slider.

FIG. 26 is a schematic view of a related art carriage, which is moved reciprocally on a guide rail, located substantially centrally between two pulleys.

FIG. 27 is a schematic view of the related art carriage located near one of the pulleys.

Claims

1. An image forming apparatus comprises: a guide rail comprising a guide surface extending in a predetermined direction;a carriage disposed on the guide surface of the guide rail;a recording head mounted on the carriage;a belt drive mechanism disposed along the guide rail and configured to move the carriage reciprocally along the guide surface, the belt drive mechanism comprising a drive pulley and a driven pulley and a timing belt, the drive pulley and the driven pulley being rotated about shafts disposed in a direction perpendicular to the guide surface upon receiving a driving force from a drive source, wherein the timing belt is stretched between the drive pulley and the driven pulley and moved circumferentially about the pulleys by the rotation of the drive pulley, andwherein the carriage comprises a carriage body on which the recording head is secured, a belt holding portion configured to hold the timing belt, and an urging member configured to urge elastically the belt holding portion to the carriage body, and the belt holding portion is disposed in a position to urge the carriage body toward the guide surface by tension of the timing belt, and is movable toward the guide surface relative to the carriage body.

2. The image forming apparatus according to claim 1, wherein the carriage comprises a gap adjustment mechanism configured to change a height of the carriage body relative to the guide surface.

3. The image forming apparatus according to claim 2, wherein the gap adjustment mechanism comprises: a sliding member configured to support the carriage body to a predetermined height in contact with the guide rail;a supporting member disposed on the carriage body and configured to support vertical movement of the sliding member;an urging member configured to urge elastically the sliding member upward;a gap adjusting member interposed between the sliding member and the supporting member in such a manner as to slide in a direction in which the carriage is reciprocally moved, the gap adjusting member including both ends thereof with respect to the direction where the carriage is reciprocally moved, both ends of the gap adjusting member protruding from the carriage body, the gap adjusting member configured to change a distance between the sliding member and the supporting member according to a position in which the gap adjusting member slides therebetween.

4. The image forming apparatus according to claim 2, wherein the gap adjustment mechanism comprises a rotary shaft comprising a plurality of sliding members on both ends, which are different in width protruding in a radially outward direction of the rotating shaft, and one of sliding members slidably contacts the guide rail.

5. The image forming apparatus according to claim 2, wherein the guide rail comprises a pair of guide rails spaced apart in a direction in which a recording medium is fed, the guide rails extend in a direction orthogonal to the direction in which the recording medium is fed, and the carriage is disposed on the guide rails so as to lie astride the guide rails.