JP2004341172A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader which realizes the improvement of the degree of freedom in terms of the arrangement of a driving pulley and is miniaturized, and also realizes the easy correction of the skew of a carriage. <P>SOLUTION: The driving pulley 44 making the carriage 3 travel is equipped with a 1st pulley part 50 driving one end side of the carriage 3 through a 1st wire 41b and a 2nd pulley part 60 driving the other end side of the carriage 3 through a 2nd wire 42b. The pulley parts 50 and 60 are disposed coaxially and adjacently to a shaft 45 orthogonal to the original placing surface of a platen glass 10, and also the phases of the pulley parts 50 and 60 are relatively shifted. An eccentric pin 70 inserted in the pulley parts 50 and 60 is rotated to shift the phase. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus that moves an optical unit mounted on a carriage relative to a document and scans the document to obtain image data, and more particularly to a technique for correcting a skew of the carriage.
[0002]
[Prior art]
As an image reading device provided in a copying machine or the like, a carriage equipped with a lamp is moved along a document placed on a platen glass, and an image of the document illuminated by the lamp is received by a CCD or the like via a lens. A configuration leading to the element is common. The carriage of such an image reading apparatus is movably supported along a guide rail provided on a housing, and is reciprocated on the guide rail by being pulled by a wire or belt operated by a motor. As a carriage driving mechanism, a driving shaft extending horizontally and perpendicular to the traveling direction of the carriage is supported at one end in the housing, and a driving pulley is fixed to both ends of the driving shaft and wound around these driving pulleys. There is a configuration in which each wire is locked to both ends of a carriage and a drive shaft is rotated by a motor, thereby pulling both ends of the carriage with each wire (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-11-327059 (paragraphs "0018" to "0019", FIG. 4)
[0004]
[Problems to be solved by the invention]
In the carriage driving mechanism described in Patent Literature 1, since the driving shaft is disposed at one end in the housing, there is a problem that the apparatus is long and it is difficult to reduce the size. In addition, since the positions of the drive shaft and the drive pulley are automatically determined, there is a restriction on the arrangement of these and the motor, and there is also a complaint that the degree of freedom of arrangement is low. Further, when a skew (inclination of the main scanning line caused by the inclination of the carriage with respect to the traveling direction) occurs in the carriage, one of the driving pulleys is rotated to shift the phase with respect to the other driving pulley. The skew is corrected by moving one end of the carriage through. However, in such a skew correction method, it is difficult to correct the skew after assembling the apparatus.
[0005]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image reading apparatus in which the degree of freedom of the arrangement of the driving pulleys is improved, the size of the apparatus is reduced, and the skew of the carriage can be easily corrected.
[0006]
[Means for Solving the Problems]
An image reading apparatus according to an embodiment of the present invention includes a frame, a platen glass provided on an upper surface of the frame, on which an original is placed, a carriage that runs along the platen glass in a sub-scanning direction, and drives the carriage. In the image reading apparatus including the driving pulley, the driving pulley includes a first pulley unit that drives one end of the carriage via a first wire and a second pulley that drives the other end of the carriage via a second wire. A pulley section is disposed coaxially and adjacent to an axis orthogonal to the original placing surface of the platen glass, and both pulley sections are relatively shiftable in phase. .
[0007]
The drive pulley of the present invention includes a first pulley portion and a second pulley portion disposed adjacent to each other on a common shaft. When the phases of the pulley portions are relatively shifted, the wire is pulled. The position of the end of the carriage can be finely adjusted via the intermediary, and the skew can be corrected. According to the present invention, it is not necessary to dispose the driving pulley outside the traveling range of the carriage in the sub-scanning direction, and the driving pulley can be disposed on the side of the traveling range of the carriage. The size can be reduced, and the degree of freedom of the arrangement of the driving pulley is improved. In addition, since the skew of the carriage is corrected by relatively shifting the phase of each pulley unit, the skew correction operation can be easily performed. The axis of the drive pulley is perpendicular to the original placing surface of the platen glass, and this means that the axis extends vertically, so that the relative phase shift of each pulley unit can be performed from above. As a result, workability can be improved.
[0008]
The present invention includes a mode that includes a shift mechanism that relatively shifts the phases of the first pulley and the second pulley. As a specific example of the shift mechanism, a shaft portion and a cam portion eccentric to the shaft portion are provided, and the shaft portion is rotatably supported by one of the first pulley portion and the second pulley portion. The cam portion is configured to be inserted into a radially extending elongated hole provided on the other of the first pulley portion and the second pulley portion. According to this shift mechanism, when the shaft is rotated, the cam pushes the inner peripheral wall surface of the elongated hole, whereby the movable pulley is rotated in the circumferential direction. Therefore, the phases of the first pulley unit and the second pulley unit are relatively shifted, and the skew of the carriage is corrected.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1. 1 is a plan view showing an image reading apparatus according to an embodiment, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. This image reading apparatus is applied to, for example, a copying machine or a facsimile. In these figures, reference numeral 1 denotes a housing (frame) constituting an outer shell of the image reading apparatus. The housing 1 is a rectangular box-shaped body, and a platen glass 10 on which an original is placed is mounted on an open upper surface thereof. A pair of guide rails 13 extending in the left-right direction (sub-scanning direction) in FIGS. 1 and 2 are attached to the bottom surface of the housing 1 in parallel with each other. The carriage 3 is slidably supported on the guide rail 13 in the longitudinal direction. A plurality of buttons 30 and 31 protruding upward are attached to the carriage 3. The buttons 30 and 31 are made of a synthetic resin such as plastic having a small coefficient of friction, and the upper end thereof has a substantially spherical shape in order to reduce frictional resistance with the platen glass 10.
[0010]
A rod lens array (Selfoc lens) 32 whose optical axis is directed vertically is attached to the upper surface of the carriage 3, and below the rod lens array 32, light received by the light passing through the rod lens array 32 is imaged. A CCD (photoelectric conversion element) 33 having a section is arranged. Further, a lamp 34 for irradiating light obliquely upward is attached to the carriage 3. Further, a slider 35 that is in sliding contact with the guide rail 13 is attached to the lower surface of the carriage 3. As shown in FIGS. 2 and 3, a compression spring 36 is interposed between the slider 35 and the frame of the carriage 3, whereby the carriage 3 is urged upward and the upper end surfaces of the buttons 30 and 31. Are elastically in contact with the lower surface of the platen glass 10.
[0011]
As shown in FIG. 3, the guide rail 13 is formed in a hat shape in cross section by bending a sheet metal, and the running surface on the upper surface is inclined downward toward the front side of the apparatus (left side in FIG. 3). At a predetermined angle. The slider 35 of the carriage 3 has a spherical sliding surface with respect to the guide rail 13, and the carriage 3 slides on the inclined running surface of the guide rail 13 toward the front side by its own weight to move. However, as shown in FIGS. 1 and 3, a force is applied to the side rail 16 provided on the inner surface of the housing 1 in the direction in which the button 37 attached to the front end surface of the carriage 3 abuts. Thus, the guide rails 13 provided on the bottom surface of the housing 1 generate pressing forces in the respective directions. As a result, when the carriage 3 is moved, the carriage 3 is guided by being pressed against the platen glass 10 in the up-down direction and by the side rail 16 in the horizontal direction, so that the carriage 3 makes a straight-forward movement in the sub-scanning direction.
[0012]
The carriage 3 is caused to travel on guide rails 13 by a drive mechanism 4 described below. As shown in FIG. 1, pulley shafts 40 extending in the vertical direction are fixed to four corners in the housing 1. Of these pulley shafts 40, as shown in FIGS. 4 and 5, a first driven pulley 41a and a second driven pulley 42a are arranged on the two inner pulley shafts (upper side in FIG. 1) in this order. Are arranged coaxially in the vertical direction and are rotatably supported. That is, the first driven pulley 41a and the second driven pulley 42a share the pulley shaft 40. As shown in FIG. 2, only the second driven pulley 42a is rotatably supported on the two pulley shafts 40 on the near side (the lower side in FIG. 1). As shown in FIG. 1, a drive pulley 44 driven by a motor 43 such as a stepping motor is provided on the back side of the housing 1.
[0013]
The drive pulley 44 is supported by the housing 1, and is rotatably supported by a shaft 45 whose axial direction is orthogonal to the document placing surface of the platen glass 10 via a bearing (not shown). As shown in FIG. 6, the drive pulley 44 is configured by combining two upper and lower pulley portions (a first pulley portion 50 and a second pulley portion 60) that are split in the axial direction. The first wire 41b is wound on the first pulley 50 and the second wire 42b is wound on the second pulley 60 a plurality of times. Then, the first wire 41b is wound around the two first driven pulleys 41a, and both ends of the first wire 41b are locked to the rear end surface of the carriage 3 as shown in FIG. The second wire 42b is wound around four second driven pulleys 42a, and both ends thereof are locked to the front end surface of the carriage 3 as shown in FIG.
[0014]
According to the drive mechanism 4, when the drive pulley 44 is driven by the motor 43, the first wire 41b and the second wire 42b operate to push the locking portions at both ends of the carriage 3 in one direction (for example, rightward). Thus, the carriage 3 travels in the same direction along the guide rail 13, and when the motor 43 rotates in the reverse direction, the carriage 3 travels in the reverse direction.
[0015]
The drive pulley 44 will be described in detail. As shown in FIG. 7, the upper first pulley portion 50 has a uniform outer diameter and a through hole 51 having an inner diameter of about half of the outer diameter formed at the shaft center. Further, two elongated hole-shaped screw insertion holes 52 penetrating through the upper and lower end surfaces and one circular shaft hole 53 are formed. In this case, the screw insertion holes 52 are formed at positions 180 ° apart from each other, and the shaft holes 53 are formed on concentric circles of the screw insertion holes 52.
[0016]
On the other hand, as shown in FIG. 8, the lower second pulley portion 60 has a timing pulley portion 61, a large-diameter portion 62, and a small-diameter portion 63 formed coaxially from bottom to top. The second pulley portion 60 is formed with a fitting hole 64 into which the shaft 45 is fitted via the bearing, and a timing belt is stretched between the drive shaft of the motor 43 and the timing pulley portion 61. The outer diameter of the large diameter portion 62 is the same as the outer diameter of the first pulley portion 50, and the small diameter portion 63 is rotatably fitted in the through hole 51 of the first pulley portion 50. The large-diameter portion 62 is formed with two screw holes 65 that open on the upper surface and a short elongated hole 66 that also opens on the upper surface and extends in the radial direction.
[0017]
When the small-diameter portion 63 of the second pulley portion 60 is fitted into the through hole 51 of the first pulley portion 50 and the two are relatively rotated about the small-diameter portion 63 as axes, the respective screw insertion holes 52 are inserted into the respective screw holes 65. , The axial hole 53 and the long hole 66 respectively. Then, the screws 46 (shown in FIG. 6) inserted into the respective screw insertion holes 52 are screwed into the respective screw holes 65 and fastened, whereby the two pulley portions 50 and 60 are connected to each other, and the drive pulley 44 is assembled. When the screw 46 is loosened from this state, the first pulley unit 50 rotates by the length of the screw insertion hole 52, and the phase with respect to the second pulley unit 60 can be shifted.
[0018]
This phase shift can be performed by an eccentric pin (shift mechanism) 70 shown in FIG. The eccentric pin 70 includes a shaft portion 71 and a cam portion 72 extending from the lower end surface of the shaft portion 71 in FIG. 9 in parallel with the axial direction of the shaft portion 71, and is shown in FIG. 9B. Thus, the cam portion 72 is thinner than the shaft portion 71 and is eccentric with respect to the cam portion 72. The outer diameter of the shaft portion 71 is set to a size that fits into the shaft hole 53 of the first pulley portion 50 and is rotatable around the axis. The outer diameter of the cam portion 72 is slightly smaller than the short diameter of the long hole 66 of the second pulley portion 60, and is set to a size that fits into the long hole 66. On the upper end surface of the shaft portion 71, a plus groove for a plus driver (screwdriver) is formed.
[0019]
To shift the phase of the first pulley unit 50 using the eccentric pin 70, the cam unit 72 is inserted into the shaft hole 53 of the first pulley unit 50 from the cam unit 72 side, and the cam unit 72 is inserted into the second pulley unit 60. The shaft portion 71 is fitted into the long hole 66 and the shaft hole 53 of the first pulley portion 50, respectively. In this state, when a Phillips screwdriver is fitted into the Phillips groove and the shaft 71 of the eccentric pin 70 is rotated around the axis, the cam 72 turns around the shaft 71, and the cam 72 turns to the second pulley 60. The inner peripheral wall of the long hole 66 is pushed. In this case, since the second pulley 60 is fixed and the first pulley 50 is movable, the cam 72 pushes the inner peripheral wall surface of the elongated hole 66 of the second pulley 60 to generate a shaft. The portion 71 moves in the circumferential direction, whereby the first pulley portion 50 rotates to shift the phase. FIGS. 10A and 10B show the operation. In the illustrated example, the eccentric pin 70 is rotated clockwise, and the first pulley 50 is rotated counterclockwise.
[0020]
As shown in FIGS. 1 and 4, a controller is fixed to the left end of the bottom of the housing 1. The controller 5 controls the rotation of the motor 43 to move the position and speed of the carriage 3 according to a program, and performs control and processing such as transferring the read image data to the image processing unit. One end of a flat band-shaped flexible harness 7 for transmitting and receiving control signals, image data signals, and the like is connected to the controller 5, and the other end of the harness 7 is connected to the carriage 3. .
[0021]
2. Next, an operation of the image reading apparatus having the above-described configuration will be described.
When the document is placed on the upper surface of the platen glass 10 and the start button on the operation panel is pressed, the motor 43 rotates, and the carriage 3 moves from the origin position shown in FIGS. The vehicle runs on the guide rail 13 while contacting the platen glass 10 and the button 37 contacting the side rail 16. Then, when the carriage 3 reaches the position shown in FIG. 5 and reading is completed, the motor 43 rotates in the reverse direction, and the carriage 3 returns to the origin position.
[0022]
While the carriage 3 is traveling to the left, the lamp 34 is turned on and the image of the original is incident on the rod lens array 32, and the light passing through the rod lens array 32 forms an image at the light receiving section of the CCD 33. Then, the CCD 33 outputs image data corresponding to the received light to the controller 5, and the controller 5 transfers the input image data to the image processing unit.
[0023]
When skew occurs in the carriage 3, as described above, the skew can be corrected by rotating the first pulley portion 50 of the drive pulley 44 by the eccentric pin 70 to shift the phase. That is, when the phase of the first pulley unit 50 is shifted, the first wire 41b moves following the rotation of the first pulley unit 50, and the rear end of the carriage 3 on which the first wire 41b is locked. The position of the section in the sub-scanning direction is finely adjusted. Therefore, the skew can be corrected by shifting the first pulley unit 50 in the direction in which the skew is corrected. After correcting the skew, the first pulley unit 50 may be coupled to the second pulley unit 60 by tightening the screw 46, and the two may be integrated.
[0024]
According to the image reading apparatus of the present embodiment, it is not necessary to arrange the drive pulley 44, the shaft 45, and the motor 43 outside the traveling range of the carriage 3 in the sub-scanning direction as in the related art. Can be arranged on the side. For this reason, the size of the apparatus can be reduced by shortening the length in the sub-scanning direction, and the degree of freedom of arrangement of the apparatuses can be improved. In addition, since the skew of the carriage 3 is corrected by shifting the phase of the first pulley unit, the skew correction operation can be easily performed. In the skew correction work, a driver is fitted to the eccentric pin 70 from above and rotated, so that workability is good.
[0025]
The eccentric pin 70 may be always mounted on the drive pulley 44, or may be used as a jig to be mounted and used only when adjusting skew. Further, as such an eccentric pin used as a jig, an eccentric pin 70 as shown in FIG. 12 is preferable. The eccentric pin 70 has a shaft portion 71 and a cam portion 72 as shown in FIG. 12A, and further has a first pulley portion 50 having a diameter larger than the shaft hole 53 above the shaft portion 71. 12 and a knob 74 are formed coaxially with the shaft 71. As shown in FIG. 12B, the shaft 71 and the cam 72 are formed as described above. By rotating the knob 74 with a finger, the phase of the first pulley unit 50 can be shifted.
[0026]
【The invention's effect】
As described above, according to the present invention, the drive pulley for moving the carriage is driven by the first pulley portion driving one end of the carriage via the first wire, and the other end of the carriage is driven by the second wire. And a second pulley portion that is driven by a pulley. These pulley portions are arranged coaxially and adjacent to an axis perpendicular to the original placing surface of the platen glass, and the phases of both pulley portions are relatively shifted. Since the configuration is made possible, the degree of freedom of arrangement of the driving pulley is improved, the size of the apparatus can be reduced, and the skew of the carriage can be easily corrected.
[Brief description of the drawings]
FIG. 1 is a plan view of an image reading apparatus according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along line II-II of FIG.
FIG. 3 is a sectional view taken along line III-III in FIG. 1;
FIG. 4 is a sectional view taken along line IV-IV of FIG. 1;
FIG. 5 is a cross-sectional view showing a state where the carriage is located at the leftmost position from the state of FIG. 4;
6A is a plan view of the drive pulley, and FIG. 6B is a side view of the drive pulley.
FIGS. 7A and 7B are a plan view and a side view, respectively, of a first pulley portion constituting the driving pulley.
FIGS. 8A and 8B are a plan view and a side view, respectively, of a second pulley section constituting the drive pulley.
9A is a perspective view of the eccentric pin of one embodiment, and FIG.
FIG. 10 is a plan view showing an operation of shifting the phase of a first pulley portion of a driving pulley using an eccentric pin in the order of (A) and (B).
FIG. 11 is a sectional view taken along line XI-XI in FIG. 1;
12A is a perspective view of an eccentric pin according to another embodiment, and FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Housing (frame), 3 ... Carriage, 4 ... Drive mechanism,
10: platen glass, 41b: first wire, 42b: second wire,
44 ... drive pulley, 45 ... shaft, 50 ... first pulley part, 60 ... second pulley part,
Reference numeral 66 denotes a long hole, 70 denotes an eccentric pin (shift mechanism), 71 denotes a shaft portion, and 72 denotes a cam portion.

Claims (3)

Frame and
A platen glass provided on the upper surface of the frame and on which a document is placed;
A carriage that travels in the sub-scanning direction along the platen glass;
In an image reading apparatus including a drive pulley that drives the carriage,
The drive pulley includes a first pulley unit that drives one end of the carriage via a first wire, and a second pulley unit that drives the other end of the carriage via a second wire. An image reading device which is disposed coaxially and adjacent to an axis perpendicular to the original placing surface of the document, and wherein both pulley portions can relatively shift the phase. The image reading device according to claim 1, further comprising a shift mechanism that relatively shifts a phase between the first pulley and the second pulley. The shift mechanism includes a shaft portion and a cam portion eccentric to the shaft portion,
The shaft portion is rotatably supported by one of the first pulley portion and the second pulley portion,
The image reading device according to claim 2, wherein the cam portion is inserted into a radially extending elongated hole provided on the other of the first pulley portion and the second pulley portion.

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