JP2000184138A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a floating carriage with a simple constitution without causing complication of the structure, increase of the cost, enhancement of maintenance, etc., due to the use of a floating carriage preventing leaf spring with respect to an image reader where the carriage is quickly moved. SOLUTION: In the image reader provided with a first carriage 1 which has a light source and a reflection mirror mounted on and is moved at a speed V, a second carriage 4 which has two reflection mirrors mounted on and is moved at a speed 1/2 V, and a wire loop drive mechanism consisting of a drive pulley 27 which moves both carriages, idler pulleys 16-2 and 17 and a wire 15, a wire clamp position 30 where the first carriage 1 is fixed to the wire is so set that it may be higher than each of wire stretch positions of the idler pulley 16-2 on the device enclosure side and the idler pullet 17 provided on the second carriage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an image reading apparatus used as a scanner or a reading optical system of an electrophotographic copying machine. The present invention relates to an image reading apparatus that can effectively prevent a read image from deteriorating due to abnormal noise that occurs and wear of a sliding portion.

[0002]

2. Description of the Related Art An image reading apparatus used for a reading optical system of a scanner or an electrophotographic image forming apparatus has a structure for reading an original set on a contact glass by a reading apparatus located immediately below the contact glass. Have. The image reading device is, for example, as shown in FIG.
A first carriage 1 mounted with a light source 2 and a reflection mirror (first mirror) 3 and supported so as to be reciprocally movable in a scanning direction;
A second carriage 4 on which two reflection mirrors (second and third mirrors) 5 and 6 are mounted and supported so as to reciprocate in the scanning direction.
And a drive mechanism for driving both carriages, a drive source, and the like.
In this configuration, the surface of the original on top 0 is scanned, and the reflected light is imaged on the CCD 12 by the lens 11. FIG. 8 is a perspective view showing the configuration of a drive mechanism for driving each carriage. A total of two drive mechanisms for driving both carriages 1 and 4 are arranged at both ends in the longitudinal direction of both carriages. , An idler pulley group 16-1 and 16-2 supported on the apparatus housing side, an idler pulley 17 rotatably supported at both longitudinal ends of the second carriage 4, and a motor as a drive source And a drive pulley 27 provided at both ends of a drive shaft 25 integrated with the timing pulley 26 via a timing belt 21 wound around an output shaft of the drive shaft 20.
And Each of the wires 15 has one end 15a fixed to a proper position of the housing. The wire extending from the one end 15a in the forward direction is connected to the idler pulleys 1 at both ends of the second carriage.
7, a first idler pulley 16-1 that is turned around in the return direction after being wound around the outer periphery of
After being reversed in the forward direction on the outer circumference of the drive shaft 25, it is wound around the outer circumference of the drive pulley 27 at both ends of the drive shaft 25 by one turn, and further extends in the forward direction. The wire 15 extending in the forward direction from the driving pulley 27 is wound around the outer circumference of the second idler pulley 16-2 by an opposite circumference and is reversed in the return direction, and both ends 30 of the first carriage 1 are clamped to a part of the wire 15. Fixed. The wire 15 extending further from the clamp fixing portion 30 of the first carriage in the return direction is
It is wound around the outer circumference of the idler pulley 17 supported by the carriage by a half turn, and then reverses in the forward direction. The other end 15b of the wire extending in the forward direction is supported by the housing via a spring 35.

In the above driving mechanism, the driving force from the motor 20 is temporarily reduced by the timing belt 21 and transmitted to the driving shaft 25 on which the timing pulley 26 is fixed. Drive pulley 27 on drive shaft 25, device housing and second
The idler pulleys 16-1, 16-2, and 17 rotatably supported on the carriage 4 and the wire 15 wound on the drive pulley 27 form a wire loop, and the first carriage 1 is positioned at a predetermined position of the wire. Has been fixed. When the drive shaft 25 is rotated, the first carriage 1 moves at a speed V,
The second carriage 4 moves on a slide rail (not shown) at a speed of 1 / 2V. When the motor 20 rotates forward, the carriages 1 and 4 move in the forward direction for scanning the original, and when the motor rotates in the reverse direction, the carriages 1 and 4 move in the reverse direction (
(Return direction). In the image reading apparatus having such a configuration, the speed at the time of return is set to be faster than the speed at the time of document scanning (forward) in order to increase the number of scans within a predetermined time. However, if the speed at the time of return exceeds about 1.5 m / s, the first carriage 1 may fly up from the slide rail for a moment at the start of return. The return speed is about 2.5m /
When the distance exceeds s, the second carriage 4 may also float from the slide rail. When the carriage rises from the slide rail, an abnormal noise such as rattling occurs, or the slide shoe fixed to the carriage wears unevenly, causing vibration in the carriage during scanning and deteriorating the image formation on the CCD. Failure occurs. As a measure to prevent such a problem, a leaf spring for preventing carriage floating may be attached to an image reading apparatus in which the carriage moves at high speed. When this prevention method is adopted, the problem of floating of the carriage can be solved, but side effects such as increased cost due to the installation of a leaf spring, the sliding noise between the leaf spring and the rail, and the need to replace a worn leaf spring are caused. .

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above. In an image reading apparatus in which a carriage moves at a high speed, the structure is complicated and the cost is increased by using a floating spring for preventing the carriage from moving. It is another object of the present invention to provide an image reading apparatus capable of preventing a carriage from being lifted with a simple configuration without increasing maintenance or the like.

[0005]

In order to achieve the above object, the present invention is directed to a first carriage mounted with a light source and a reflecting mirror and moving at a speed V, and a first carriage mounted with two reflecting mirrors. A wire clamp position for fixing the first carriage to the wire in an image reading apparatus having a second carriage that moves at 1 / 2V, and a drive pulley that moves both carriages, a wire loop drive mechanism that includes an idler pulley and a wire. However, it is characterized in that it is set to be higher than each wire extension position of the idler pulley on the device housing side and the idler pulley provided on the second carriage. According to a second aspect of the present invention, there is provided a first carriage mounted with a light source and a reflecting mirror and moving at a speed V, a second carriage having two reflecting mirrors and moving at a speed of 1 / 2V,
An image reading apparatus having a driving pulley for moving both carriages, an idler pulley, and a wire loop driving mechanism including a wire, wherein: a wire clamp position for fixing the first carriage to the wire; and a wire for the idler pulley provided on the second carriage. The overhang position is set to be higher than the overhang position of the wire of the idler pulley on the device housing side. According to a third aspect of the present invention, there is provided a first carriage mounted with a light source and a reflecting mirror and moving at a speed V during scanning, a second carriage having two reflecting mirrors and moving at a speed 1/2 V during scanning, In an image reading apparatus having a driving pulley for moving both carriages, a belt loop driving mechanism including an idler pulley and a timing belt, a belt clamp position for fixing the first carriage to the belt is provided by a driving pulley on an apparatus housing side, and an idler. It is characterized in that it is set to be higher than each belt overhang position of the pulley. According to a fourth aspect of the present invention, a first light source and a reflecting mirror are mounted and move at a speed V.
An image reading apparatus including a carriage, a second carriage having two reflection mirrors and moving at a speed of 1/2 V, and a belt loop driving mechanism including a driving pulley, an idler pulley, and a timing belt for moving both carriages. Wherein each of the belt clamp positions for fixing the first carriage and the second carriage to the respective belts is set to be higher than the respective belt extension positions of the drive pulley on the apparatus housing side and the idler pulley.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 is a schematic configuration diagram of a driving mechanism used in an image reading apparatus according to an embodiment of the present invention.
7 and 8, the same parts as those in the mechanical diagrams shown in FIGS. 7 and 8 will be denoted by the same reference numerals. The image reading apparatus according to this embodiment includes a first carriage 1 moving at a speed V, a second carriage 4 moving at a speed of 1/2 V, and a driving force transmitted to both carriages 1 and 4 to forward and return directions. It is composed of a drive mechanism including a wire loop for moving forward and backward, a drive source, and the like. The characteristic configuration of this embodiment is the first carriage 1
From the idler pulley 16-2 supported by the device housings located on both sides of the wire clamp of the first carriage 1 and the respective wire overhanging positions W1, W2 of the idler pulley 17 on the second carriage 4. Is also configured to be higher by a predetermined height h. With such a configuration, a tension is generated by the wire 15 for pressing the first carriage 1 downward, and the carriage can be prevented from floating. The method of setting the wire clamp position 30 at a position higher than the idler pulleys 16-2 and 17 on both sides is to set the wire clamp positions 30 at both ends of the first carriage 1 higher by a height h in advance. Good. The wire loop drive mechanism having the configuration as shown in FIG. 1 was mounted on an image reading apparatus having a return speed of about 2 m / s, and the state where the first carriage 1 was lifted off a slide rail (not shown) upon return was visually confirmed. Increase the wire clamp height h of the first carriage 1 by +1.
No lifting occurred when set to 0 mm or more. Also, when the noise near the carriage at the start of the return was measured while changing the height of the wire clamp position 30,
The results are as shown in Table 1 shown in FIG. Since the noise level is substantially constant when the height of the wire clamp position exceeds +1.0 mm, it can be confirmed that no floating has occurred since the height of +1.0 mm.

Next, FIG. 3 is a schematic view of the configuration of a drive mechanism according to a second embodiment of the present invention. When the return speed of each carriage exceeds a predetermined speed, for example, 2.5 m / s, the first and second drive mechanisms are started.
The carriages 1 and 4 are both easily lifted off the slide rails when returning, but this embodiment provides a configuration for preventing the occurrence of such lifts and noise, abnormal noise, sliding wear, and other problems resulting therefrom. It is. The driving mechanism of this embodiment includes a height of the wire clamp position 30 of the first carriage 1 and an idler pulley 17 of the second carriage 4.
The above problem is solved by setting the height of the wire overhang position W3 to be higher than the wire overhang position W1 of the idler pulley 16-2 on the device housing side and the fixed position of the wire end 15a. With this configuration,
The first and second carriages 1 and 4 are pressed against the slide rails by the action of the tension of the wire 15 and can be prevented from floating.

FIG. 4 is a plan view showing a main part of an image reading apparatus using a timing belt as a component of a carriage driving mechanism. This driving mechanism is used to drive the first carriage 1. Two first timing belts 40 fixed in place at clamp positions 41 at both ends of the first carriage, and two timing pulleys for extending each first timing belt 40 endlessly, that is, the apparatus housing side And a drive timing pulley 43 supported by a drive shaft 45. The drive mechanism further includes two second timing belts 50 fixed at appropriate positions at clamp positions 51 at both ends of the second carriage to drive the second carriage 4.
It has two timing pulleys for extending each second timing belt 50 endlessly, that is, an idler pulley 52 supported on the device housing side and a drive timing pulley 53 supported on the drive shaft 45. Both drive timing pulleys 43 and 53 have their shafts fixedly supported by a drive shaft 45, and a drive pulley 55 has a shaft center fixed to one end of the drive shaft 45. Timing pulley 61 fixed to the output shaft of motor 60 as a driving source
The drive pulley 55 is connected to the drive pulley 55 by a timing belt 62. When the motor 60 is driven to rotate in the normal rotation direction, the drive shaft 45 rotates via the timing pulley 61, the timing belt 62, and the drive pulley 55, and moves both carriages 1, 4 in the forward direction. When the motor 60 rotates in the reverse direction, the carriages 1 and 4 move in the return direction. When the diameter of the timing pulleys 42 and 43 for extending the first timing belt 40 is 2r, the timing pulleys 52 and 5 for extending the second timing belt 50 are provided.
The diameter of 3 is r. Accordingly, the torque transmitted from the drive shaft 45 to each of the timing pulleys 43 and 53 causes the second
The carriage 4 can move at a speed (１ ／ · V) of the moving speed V of the first carriage. The belt loop drive mechanism composed of the timing belt has an advantage that the assemblability is easier than the drive mechanism having a wire loop structure composed of a wire.

In the belt loop driving mechanism having such a configuration, when the return speed exceeds 1.5 m / s, the first
The carriage 1 may rise from a slide rail (not shown), which may cause abnormal noise, noise, and abrasion of the sliding portion. FIG. 5 shows an example of a configuration for solving such a problem. The height of the clamp position 41 of the first carriage 1 is adjusted by the drive timing pulleys 4 located on both sides of the first carriage.
3. By making the timing belt pulley 42 of the idler timing pulley higher than the overhang positions W4 and W5,
The first carriage 1 can be pressed downward by the tension of the belt 40, and the first carriage 1 can be prevented from floating from the slide rail.

In an image reading apparatus in which each carriage is driven by a timing belt, if the return speed exceeds 2.5 m / s, both the first and second carriages 1 and 4 are likely to float from the slide rails, resulting in abnormal noise. ,noise,
Abrasion of the sliding portion may occur. FIG. 6 shows an example of a configuration for solving such a problem. The height of the clamp position 41 of the first carriage 1 is adjusted by the drive timing pulley 43 located on both sides of the first carriage 1 and the timing belt of the idler timing pulley 42. Overhang position W
4 and W5, and the height of the clamp position 51 of the second carriage 4 is set to the drive timing pulley 53 and the idler timing pulley 52 on both sides of the second carriage.
By setting the timing belts to be higher than the projecting positions W6 and W7 of the timing belts,
The two carriages 1 and 4 can be pressed down by the two forces of zero, and the first and second carriages can be prevented from floating. In each of the above embodiments, a digital scanner has been described as an example. However, it is needless to say that the drive mechanism of the present invention can be applied to a scanner section of an analog copying machine that forms an image on a photosensitive member.

[0011]

As described above, according to the present invention, in an image reading apparatus in which two carriages move forward and backward on a slide rail at high speed, the structure is complicated and the cost is increased by using a floating spring for the carriage. In addition, it is possible to prevent the carriage from floating with a simple configuration without increasing maintenance. That is, the invention of claim 1 includes a first carriage mounted with a light source and a reflecting mirror and moving forward and backward at a speed V, a second carriage mounted with two reflecting mirrors and moving forward and backward at a speed of 1 / 2V, In an image reading apparatus having a drive pulley for moving the carriage, an idler pulley, and a wire loop drive mechanism including a wire, and the return speed of the carriage is about 1.5 m / s or more, the wire clamp position of the first carriage is set to Since each of the idler pulleys respectively provided on the body and the second carriage is configured to be higher than the wire projecting position,
The floating of the first carriage can be prevented without using a leaf spring for preventing the floating of the carriage, and abnormal noise and uneven wear of the slide shoe can be prevented. According to a second aspect of the present invention, there is provided a scanner having a wire loop driving mechanism having the same configuration as that of the first aspect, wherein the scanner has a return speed of about 2.5 m / s or more, and is provided at the wire clamp position of the first carriage and the second carriage. The wire extension position of the idler pulley is set higher than the wire extension position of the idler pulley on the device housing side, so that the first and second carriages can be prevented from floating, generating abnormal noise upon return, and uneven wear of the slide shoe. Can be prevented from occurring. According to a third aspect of the present invention, there is provided a first carriage mounted with a light source and a reflecting mirror and moving forward and backward at a speed V, a second carriage mounted with two reflecting mirrors and moving forward and backward at a speed of 1/2 V, and each carriage. In the image reading apparatus having a belt loop driving mechanism including a driving pulley, an idler pulley, and a timing belt for moving back and forth, and a return speed of about 1.5 m / s or more, the belt clamp position of the first carriage is set to Since the belt is set to be higher than each belt pull-out position of the drive pulley and idler pulley on the body side, the floating of the first carriage can be prevented, and abnormal noise at return and uneven wear of the slide shoe can be prevented. . According to a fourth aspect of the present invention, there is provided an image reading apparatus provided with a belt loop drive mechanism having a configuration equivalent to that of the third aspect and having a return speed of about 2.5 m / s or more. The belt clamp position is set higher than the belt extension positions of the drive pulley and idler pulley on the device housing side, so that the first and second carriages can be prevented from floating, generating abnormal noise on return and uneven wear of the slide shoe. Can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first example of a driving mechanism of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a noise state when the clamp position height h of the drive mechanism of FIG. 1 is variously changed.

FIG. 3 is a schematic view showing a second example of a driving mechanism of the image reading apparatus according to the embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating a configuration example of a drive mechanism of an image reading apparatus according to another embodiment of the present invention.

FIG. 5 is a schematic view showing another example of the configuration of the driving mechanism of the image reading apparatus of the embodiment shown in FIG. 4;

FIG. 6 is a schematic diagram showing another configuration example of the driving mechanism of the image reading apparatus of the embodiment shown in FIG. 4;

FIG. 7 is a front vertical sectional view showing a configuration of a main part of a conventional image reading apparatus.

FIG. 8 is a perspective view showing a configuration of a conventional driving mechanism.

[Explanation of symbols]

1 First carriage, 2 light sources, 3 reflection mirrors (1st carriage
Mirror), 4 second carriage, 5, 6 reflection mirror,
10 contact glass, 11 lens, 12 CCD,
Reference Signs List 15 wire, 16-1, 16-2 idler pulley group, 17 idler pulley, 20 motor, 21 timing belt, 25 drive shaft, 26 timing pulley, 27 drive pulley, 30 clamp fixing portion of first carriage, 40 first Timing belt, 42 idler pulley, 43 drive timing pulley, 45 drive shaft, 50 second timing belt, 51 clamp position, 52 idler pulley, 53 drive timing pulley, 55 drive pulley, 60 motor, 61 timing pulley, 62 timing belt .

Claims (4)

[Claims] 1. A first carriage mounted with a light source and a reflecting mirror and moving at a speed V, a second carriage mounted with two reflecting mirrors and moving at a speed of 1 / 2V, and a drive for moving both carriages In an image reading apparatus having a pulley, an idler pulley, and a wire loop driving mechanism including a wire, a wire clamp position for fixing the first carriage to the wire includes an idler pulley on the apparatus housing side and an idler pulley provided on the second carriage. An image reading apparatus characterized in that it is set to be higher than each of the wire overhang positions. 2. A first carriage mounted with a light source and a reflecting mirror and moving at a speed V, a second carriage having two reflecting mirrors and moving at a speed of 1 / 2V, and a drive for moving both carriages In an image reading apparatus having a pulley, an idler pulley, and a wire loop driving mechanism including a wire, a wire clamp position for fixing the first carriage to the wire and a wire extension position of the idler pulley provided for the second carriage are provided in an apparatus casing. An image reading apparatus characterized in that it is set to be higher than a wire extension position of an idler pulley on a body side. 3. A first carriage mounted with a light source and a reflecting mirror and moving at a speed V during scanning, a second carriage having two reflecting mirrors and moving at a speed of 1 / 2V during scanning, and both carriages. And a belt loop driving mechanism including an idler pulley and a timing belt, a belt clamp position for fixing the first carriage to the belt is provided by a driving pulley on the device housing side and an idler pulley. An image reading apparatus characterized in that it is set to be higher than each belt overhang position. 4. A first carriage mounted with a light source and a reflection mirror and moving at a speed V, a second carriage having two reflection mirrors and moving at a speed of 1 / 2V, and a drive for moving both carriages In an image reading apparatus having a belt loop driving mechanism including a pulley, an idler pulley, and a timing belt, each belt clamp position for fixing the first carriage and the second carriage to each belt, respectively, a driving pulley on an apparatus housing side; An image reading apparatus characterized in that it is set to be higher than each belt extension position of an idler pulley.