JP2002317389A - Wire rope for transmitting driving force and image- reading device produced by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a force-transmitting wire rope enabling the easy recognition of the twisting direction of the rope main body and the sure transportation stability of a driven object by coinciding the frictional property of a pair of rope main bodies to uniformize the displacement in the thrust direction on a pulley. SOLUTION: Seven element wires 46a are twisted in S or Z direction to obtain a strand. Seven strands 46b, 46c each made of seven element wires are twisted in S or Z direction to form two kinds of rope bodies 46L, 46R. The rope bodies are used in a pair and the outer circumference of each rope body is covered with a covering resin layer made of the same material and having different colors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rope for transmitting a driving force used in a copying machine, a printer, a facsimile, or an image reading apparatus as an input means of an image forming apparatus having these functions, and a driving force transmitting wire rope. The present invention relates to improvement of an image reading apparatus used.

[0002]

2. Description of the Related Art An image forming apparatus utilizing an electrophotographic process, such as a copying machine, a printer, a facsimile machine, etc., has an image reading device as input means for image information. An image reading device (image scanner) having no image forming unit is also known.

The image reading apparatus includes a first scanner having a light source, a reflector, and a first mirror, and a second scanner having second and third mirrors for guiding a document reflected light to a photosensitive member or a CCD. Each scanner is engaged with a wire rope driven by a motor and driven in the sub-scanning direction. This wire rope is stretched by a pulley, and the pulley is a drive pulley directly connected to an output shaft of a motor, an idle pulley rotatably supported on a frame of the apparatus main body, and further rotatably supported by a carriage of a scanner. Carriage pulley.

When driving the scanners in the sub-scanning direction, the fact that the scanners are parallel to the main scanning direction and the relationship between the wire rope extending in the sub-scanning direction and each scanner are orthogonal when viewed from the plane. It is necessary from the viewpoint of running stability that the driving force transmitted by the wire rope is in a direction perpendicular to the scanner.

What is important in the moving mechanism of the scanner having such a configuration is to ensure stable running without micro-vibration or the like. With respect to the prevention of micro-vibration during running of the scanner, particularly high precision is required for flat image scanners and digital copying machines, and several steps higher than the precision of analog copying machines are required. However, in practice, unless the components constituting the drive system and the transmission system have a high-precision structure and assembling accuracy, micro-vibration is generated, which adversely affects the image quality.

As described above, a moving member such as a wire rope or a timing belt is used to move the scanner. However, since the wire rope has a lower rate of vibration, a power source having excellent flexibility is used. It is preferably used as a transmission element.

[0007] The wire rope has a single twist structure composed of a rope body formed by twisting several strands into a rope form, and a multiple twist structure composed of a rope body formed by twisting several strands of the single twist structure. And the above-mentioned single-twisted and multi-twisted structures are individually formed in a spirally twisted form of strands and strands. Therefore, the rope body (multi-twisted) On the outer periphery of the structure, there are several spiral concave grooves adjacent to each other.

[0008] As a general behavior when the wire rope (rope main body) is wired and operated on the pulley wheel, when the wire rope wound around the pulley wheel is wound up or sent out, the operation is stopped. Due to the spiral structure of the wire rope and the elasticity of the wire rope itself, not only the tension along the core direction of the wire rope but also the tension in the thrust direction of the pulley wheel being wired is component force. Occur simultaneously. The direction in which the tension in the thrust direction is generated is related to the twisting direction of the wire rope, and differs in the winding of the wire rope and the feeding of the wire rope, and occurs in any direction. As a result, the winding position of the wire rope fluctuates along the thrust direction of the pulley wheel, causing skew and fine vibration of the scanner, and instability of the magnification, image distortion, image jitter, and other image quality maintenance problems. Is causing this. In order to solve such a problem, when the wire ropes are routed to the driving pulleys respectively disposed at both sides (left and right) in the main scanning direction, the S-twisted ropes whose twisting directions are opposite to each other. The main body (see FIG. 4A) and the Z-strand rope main body (see FIG.
(B)) is used as a pair to make the force obliquely applied to the scanner uniform on the left and right.

[0009]

When using a rope body having different twisting directions on the left and right, it is necessary to accurately identify the type according to the twisting direction and then assemble the pulley into a pulley or the like. According to the direction, a method is adopted in which only the outer peripheral surface is coated with a resin layer of a different color to facilitate identification. In this case, the outer peripheral surface of the rope body is covered with the resin layer because the above-mentioned spiral concave grooves adjacent to each other improve the non-smoothness of the outer periphery and uneven wear of the outer periphery due to the lubrication effect of the resin layer. It also has the purpose of suppressing it.

[0010] However, depending on the type of the covering material,
Friction characteristics may differ from each other. For this reason, even if the type of the rope main body is identified and wired on the pulley, a small difference occurs in the amount of variation in the thrust direction on the pulley between the left and right rope main bodies. When used, this may cause a problem in maintaining image quality, so that the running stability of a driven object such as a carriage cannot be achieved, and a countermeasure has been desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to make it possible to easily identify the twist direction of a rope main body, and to make it easy to identify the twist direction of a pair of rope main bodies. Provided is a drive transmission wire rope capable of securing the running stability of a driven object by making the amount of variation in the thrust direction on a pulley equal by friction characteristics, and an image reading apparatus using the same. It is in.

[0012]

In order to achieve the above object, the present invention presupposes a driving force transmitting wire rope constituted by a rope body in which strands or strands are twisted. Then, a pair of the rope bodies is used, and the outer peripheral surface of each of the rope bodies is covered with a resin layer made of the same base material and having different color tones.

According to this specific matter, the type of the rope main body (the twist direction of the rope main body) can be easily identified by the color tone of the coating resin layer on the outer peripheral surface of the rope main body. Since the resin layer covering the outer peripheral surface of the rope main body is formed of the same base material, the friction characteristics of the pair of rope main bodies used as a pair on the left and right sides match, thereby, The amount of fluctuation in the thrust direction on the pulley becomes equal, and the running stability of the driven object can be ensured.

On the other hand, the wires or strands of the rope body used as a pair are formed of the same wire, and the wires or strands are treated by metal plating of different tones, so that the respective rope bodies are individually treated. When the outer peripheral surface is coated with a transparent resin layer made of the same base material, the type of rope main body (the direction in which the rope main body is twisted) can be easily identified by the color tone of the metal plating applied to the strand or strand. You can do it. And since the wires or strands are made of the same wire, the mechanical properties of the rope main body do not change even if the type of metal plating is different, and furthermore, the resin covering the outer peripheral surface of each rope main body Because the layers are formed of the same substrate,
The friction characteristics etc. of the rope bodies used as a pair on the left and right sides match, so that the amount of fluctuation in the thrust direction on the pulleys of the rope bodies on the left and right sides is equal, ensuring the running stability of the driven object It is possible to do.

In particular, the following configuration is given as a specific example when a power transmission wire rope is used in an image reading device.

That is, a carriage having an optical system for main-scanning image information of a document is mounted, a driving force transmitting wire rope for moving the carriage in the sub-scanning direction, and each driving force transmitting wire rope. A driving force transmitting wire rope used in an image reading apparatus including a pulley that rotates and drives the pulley and a driving source that rotates each pulley is constituted by a pair of rope bodies in which strands or strands are twisted. I do. The outer peripheral surfaces of each of the pair of rope bodies are covered with resin layers made of the same base material and having different colors.

According to this specific matter, when the present invention is applied to a double-sided wire drive type image reading apparatus that drives a carriage equipped with a scanner from both the left and right sides, the type of the rope main body depends on the color of the resin layer covering the pair of rope main bodies. (Twist direction of the rope body) can be easily identified, and appropriate types of rope bodies are respectively routed to the pulleys on both sides, so that skewing and vibration of the carriage can be suppressed.

Moreover, since the resin layer covering the outer peripheral surface of each of the rope bodies is formed of the same base material, the pair of rope bodies used on both the left and right sides have the same friction characteristics and the like. The amount of fluctuation in the thrust direction on the pulley can be made equal, and the parallelism, orthogonality, and running stability with respect to the scanning direction of the scanner can be maintained.

On the other hand, the driving force transmitting wire rope used in the image reading apparatus is constituted by a pair of rope bodies formed by twisting strands or strands made of the same wire, and the pair of rope bodies is composed of a pair of rope bodies. Alternatively, the strands are treated with metal plating of different colors. When the outer peripheral surface of each of the rope bodies is covered with a transparent resin layer made of the same base material, the color tone of the metal plating applied to the strands or strands constituting the rope body The type (twisting direction) of the rope main body is identified, and the appropriate type of rope main body can be routed to the pulleys on both sides, so that the skew and vibration of the carriage can be suppressed.

Furthermore, since the wires or strands are made of the same wire, the mechanical properties of the pair of rope bodies do not change even if the type of metal plating is different, and the outer peripheral surface of each of the rope bodies is covered. Since the resin layers are formed of the same base material, the friction characteristics of a pair of rope bodies used on both the left and right sides match, and the amount of variation in the thrust direction on the pulley of each rope body is made equal. Thus, it is possible to maintain parallelism, orthogonality, and running stability with respect to the scanning direction of the scanner.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing a schematic structure of a flatbed type image reading apparatus 1 (image input apparatus). Light from a light source 12 irradiates a document 2 fixed on a contact glass 11 to the document. The reflected light is reflected by the first to third mirrors 13,
The light is reflected by 14 and 15 and turned back. The light is condensed by a lens 16 and then imaged on a CCD 17. The CCD 17 performs photoelectric conversion.

The light source 12 and the first mirror 13 constitute a first scanner 32 mounted on a first carriage 31 and independently moving in the sub-scanning direction. On the other hand, the second and third mirrors 14 and 15 are mounted on a second carriage 33 and constitute a second scanner 34 that independently advances and retreats in the sub-scanning direction.

FIG. 3 is a perspective view of the image reading apparatus 1. The image reading apparatus 1 includes a first scanner 32 slidably supported on a pair of left and right guide rails 35, 35, and a pair of left and right sides. Guide rails 36, 36
A drive mechanism 4 is provided for driving the second scanners 34 slidably supported above in the respective sliding movement directions. The drive mechanism 4 includes a motor 41 as a drive source.
And a drive gear 42 meshing with an output gear 41a of the motor 41, and an output rod 4 rotatably connected to a substantially intermediate portion.
2, drive pulleys 43, 43 rotatably connected to the left and right ends of the output rod 42, and a carriage rotatably supported on both left and right sides of the second scanner 34 (left and right sides of the second carriage 32). Pulleys 44, 44, and a pair of left and right idle pulleys 4 rotatably supported by the apparatus body
5 and 45, and a pair of left and right rope bodies 46 which are wound around these pulleys 43, 44 and 45 and transmit the driving force.
L, 46R.

As shown in FIG. 3, the left and right rope bodies 46
L and 46R prepare seven bundles of S twisted strands 46b in which seven strands 46a are twisted clockwise when viewed from the twisting direction (upward in FIG. 4), and further clockwise viewed from the twisting direction. An S-twisted strand obtained by S-twisting and twisting (shown in FIG. 4A) and a Z-twisted strand 46 obtained by twisting seven strands 46a counterclockwise as viewed in the twisting direction.
c, seven bundles of which are Z-twisted (shown in FIG. 4 (b)) by further twisting them in a counterclockwise direction as viewed from the twisting direction, and twisting them together. The driving force transmitting wire rope 46 is formed by the main bodies 46L and 46R.
Is composed.

Each carriage pulley 44 is connected to the rope body 4
It has two pulley grooves (not shown) that can wind 6L (46R) around both inside and outside. As shown in FIG. 2, a rope body 46 </ b> L (46) wound around the idle pulley 45 is provided in a pulley groove outside each carriage pulley 44.
R) is wound around one end of the rope body and makes a U-turn. One end of the rope body 46L (46R) is fixed to the apparatus body in a state where tension is applied by an elastic member 47 such as a spring. On the other hand, the other end side of the rope body 46L (46R) wound around the driving pulley 43 is wound around the pulley groove inside each carriage pulley 44, makes a U-turn, and is fixed to the apparatus body. In addition, each rope body 4
The 6L and 46R are locked to the left and right sides of the first scanner 32 (the left and right sides of the first carriage 31) between the drive pulley 43 and the carriage pulley 44. Then, when each drive pulley 43 rotates clockwise in FIG. 3 and sends out the other end side of each rope body 46L, 46R, each carriage pulley 44 rotates clockwise, and one end side of each rope body 46L, 46R moves. You will be pulled. This will be described with reference to pulleys.
Since 4 is a moving pulley, it rotates at half the speed (linear speed) at which the rope pulleys 46L and 46R are sent out by the respective drive pulleys 43. Therefore, the first scanner 32 scans and moves at the same speed as each of the rope bodies 46L and 46R.
The second scanner 34 scans and moves at half the speed of each of the rope bodies 46L and 46R. In this case, it is important that the positional relationship between each of the scanners 32 and 34 extending in the main scanning direction and each of the rope bodies 46L and 46R extending in the sub-scanning direction is orthogonal in plan view.

As a characteristic part of the present invention, as shown in FIG. 5, coating resin layers 5 having different color tones are provided on the outer peripheral surfaces of the rope bodies 46L and 46R. The coating resin layer 5 does not have a structure in which the resin layer is coated only on the outer peripheral surfaces of the rope bodies 46L and 46R, but is integrally fixed to the outer circumferences of the rope bodies 46L and 46R by melting and solidifying the coating resin. is there.

The method of forming the coating resin layer 5 is as follows. That is, the thermoplastic resin is applied to the rope body 46 by extrusion molding, electrostatic coating, sintering, dipping, or the like.
The outer peripheral surface of L, 46R is coated, and the coated resin is heated, melted, and solidified by a method such as high-frequency heating, energizing overheating, and heater heating. Considering the uniformity of the molten state of the coating resin, the solidification stability, the melting time, and the like, high-frequency heating is preferred. Even when the high-strength rope bodies 46L, 46R are used for the purpose of improving the strength and durability of the rope bodies 46L, 46R, the torsional deformation of the rope bodies 46L, 46R is fixed by the fixing action of the heated and molten coating resin. You. In short, the resin is impregnated into the space between the strands 46a and the strands 46b and 46c, as in the case where the coating resin fills a large number of concave grooves existing on the outer periphery of the rope bodies 46L and 46R. The movements of the individual wires 46a and the strands 46b and 46c are slightly restrained, and the individual wires 46a and
6b and 46c are suppressed from being elongated. Further, by providing the coating resin layer 5 on the outer peripheral surfaces of the rope bodies 46L and 46R, the smoothness of the outer peripheral surfaces of the rope bodies 46L and 46R is improved, and the cross-sectional shape is made closer to a perfect circle.

As the thermoplastic resin forming the coating resin layer 5, polyethylene, polypropylene, 6-66 copolymer nylon, 6-66-12 copolymer nylon and the like are applied. If the coating thickness of the rope main bodies 46L, 46R is too large, the coating diameter of the rope main bodies 46L, 46R becomes large, and at the same time, when the rope main bodies 46L, 46R are routed and driven on the pulleys 43 to 45, the coating resin layer 5 If the thickness is too small, the fixing strength to the rope main bodies 46L and 46R cannot be sufficiently obtained.
It is considered that about 0.01 mm to 0.1 mm is suitable. The coating resin layer 5 applied to the outer peripheral surfaces of the rope bodies 46L and 46R is formed of the same resin material, and the coating resin layer 5 is formed by appropriately selecting pigments and coloring agents to be compounded in the resin production stage. Rope body 46 in different colors
The type (twist direction) of L and 46R can be identified.

(Effects of Embodiment) As described above,
In the image reading apparatus 1, rope main bodies 46L and 46R having different twisting directions are used as the drive transmission wire ropes 46 used as a pair of left and right, and a coating resin applied to the outer peripheral surface of each of the rope main bodies 46L and 46R. Layer 5
Are formed of the same resin material, but by appropriately selecting pigments and coloring agents to be blended in the resin production stage, the type (twist direction) of the rope bodies 46L and 46R can be changed according to the color tone of the coating resin layer 5. The rope bodies 46L and 46R of an appropriate type (twist direction) can be easily arranged on the pulleys 43 to 45 or the like.

Moreover, the covering resin layer 5 covering the outer peripheral surfaces of the rope bodies 46L and 46R is made of the same resin material (the same base material).
, Mechanical properties such as elasticity and frictional characteristics of the rope bodies 46L and 46R used as a pair on both the left and right sides match, and the rope bodies 46L and 46R are used.
By making the amount of change in the thrust direction of the R on the pulleys 43 to 45 equal, parallelism, orthogonality, and running stability of the scanners 32 and 34 with respect to the scanning direction can be secured.
That is, since the amount of fluctuation in the thrust direction of the pair of rope bodies 46L and 46R in the left and right pairs is the same and the directions of fluctuation are different, the influences of the rope bodies 46L and 46R are canceled each other, and as a result, the skew of the scanners 32 and 34 is prevented. You can do it. As a result, the rope body 4 on the drive pulley 43
The amounts of change in the positions of the ropes 6L and 46R in the thrust direction are made uniform, and the pulling directions by the rope bodies 46L and 46R are parallel to the sub-scanning direction, so that the scanner 3
The fine vibrations of 2, 34 are suppressed, and the causes of problems in maintaining the image quality, such as unstable magnification, image distortion, and image jitter, can be eliminated.

(Other Embodiments) In the above embodiment, the type (twist direction) of the rope bodies 46L and 46R is determined by the color tone of the coating resin layer 5 by the pigment or the colorant compounded in the resin production stage. As shown in FIG. 6, as shown in FIG. 6, a wire 61 a made of the same wire is treated with metal plating 62 having different color tones in different twist directions.
For example, a plating layer thickness of 0.05 μm to 0.015 using a metal having a characteristic color tone such as brass, bronze, copper, and zinc.
A treatment by a metal plating 62 of about μm is performed, and the strands 61b (or 61c) of seven bundles in which seven strands 61a are twisted are further twisted to obtain a rope body 61L, 61L.
R is integrally fixed to the outer peripheral surfaces of the rope bodies 61L and 61R by melting and solidifying a transparent coating resin made of the same base material. In addition, as in the above embodiment, the coating resin layer 7 is melted and solidified by coating a thermoplastic resin on the outer peripheral surface of the rope body and heating and melting the coating resin by a method such as high-frequency heating, energizing overheating, and heater heating. It is performed by post-solidification. In this case, the rope bodies 61L, 61
The coating resin layer 7 applied to the outer peripheral surface of the R is formed of the same transparent resin material, but the metal plating 62 applied to the strand 61a in the manufacturing steps of the rope bodies 61L and 61R.
By appropriately selecting the type, the type (twist direction) of the rope bodies 61L and 61R can be easily identified by a unique color tone having a metal plating 62 layer, and the appropriate type (twist direction) of the rope bodies 61L and 61R can be easily identified. 61R pulley 4
3 to 45 can be routed. And the wire 61a
Are made of the same wire, the mechanical properties of the rope bodies 61L, 61R remain the same even if the type of the metal plating 62 is different.
Since the coating resin layer 7 that covers the outer peripheral surface of the 1R is formed of the same base material, the friction characteristics and the like of the pair of rope bodies 61L and 61R used as a pair on the left and right sides match, whereby the left and right both sides are matched. The fluctuation amounts of the rope bodies 61L and 61R in the thrust direction on the pulleys 43 to 45 become equal, and the coating resin layer 7 covering the outer peripheral surfaces of the rope bodies 61L and 61R is made of the same resin material (the same base material). By being formed, the rope bodies 61L and 61R used as a pair on the left and right sides have the same mechanical properties such as elasticity and frictional properties, and the pulley 4 of each rope body 61L and 61R.
By making the amount of fluctuation in the thrust direction above 3 to 45 equal,
The degree of parallelism, orthogonality, and running stability of the scanners 32 and 34 with respect to the scanning direction can be ensured, and skew of the scanners 32 and 34 can be prevented.

In this embodiment, seven wires 46a are used.
Although the rope bodies 46L and 46R are formed by further twisting the seven bundles of strands 46b obtained by twisting the strands, the rope body may be formed by twisting seven strands.

Further, in the present embodiment, the rope body 46
Although the coating resin layer 5 is provided on the outer peripheral surfaces of the L and 46R to make the cross-sectional shape close to a perfect circle, as shown in FIG. 7, the strands 46b (or the spirals) extending spirally on the outer peripheral surfaces of the rope bodies 46L and 46R. The covering resin layer 8 is provided only in the vicinity of the concave groove between 46c) and the rope bodies 46L, 46
The cross-sectional shape of R may be substantially hexagonal. The coating resin layer 8 is integrally fixed to the outer peripheral surfaces of the rope bodies 46L and 46R by melting and solidifying the coating resin.

[0035]

As described above, according to the present invention, the following effects are exhibited. First, by covering the respective outer peripheral surfaces of a pair of rope main bodies with resin layers made of the same base material and having mutually different colors, the color tone of the coating resin layer on the outer peripheral surfaces of the rope main bodies allows the rope main body to be twisted in the twist direction. In addition to easy identification, the amount of fluctuation in the thrust direction on the pulleys of the left and right rope bodies is equalized by matching the friction characteristics of the rope bodies covered with the resin layer made of the same base material. The running stability of the driven object can be ensured.

By using the pair of rope bodies in the image reading apparatus, an appropriate type of rope bodies can be routed to the pulleys on both sides to suppress skew and vibration of the carriage. The variation in the thrust direction on the pulley is made equal by matching the friction characteristics of the rope main body and the like, and the parallelism, orthogonality, and running stability with respect to the scanning direction of the scanner can be maintained.

On the other hand, the wires or strands are subjected to metal plating of different colors, and the outer peripheral surface of each rope body is covered with a transparent resin layer of the same base material. The type can be easily identified. In addition, by making the strands or strands of the same wire material, the mechanical properties of the rope body are made uniform regardless of the type of metal plating, and the friction properties of a pair of rope bodies by the resin layer of the same base material. And the amount of variation in the thrust direction on the pulleys of the rope bodies on both the left and right sides can be made equal to ensure the running stability of the driven object.

By using the pair of rope bodies in the image reading apparatus, it is possible to wire an appropriate type of rope body to the pulleys on both sides, thereby suppressing skewing and vibration of the carriage. In addition, by configuring the strands or strands with the same wire, without changing the mechanical characteristics of each rope main body due to the difference in the type of metal plating, the friction characteristics of a pair of rope main bodies due to the resin layer of the same base material, etc. Together with the coincidence, the amount of variation in the thrust direction of each rope body on the pulley can be made equal, and the parallelism, orthogonality, and running stability with respect to the scanning direction of the scanner can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image reading apparatus using a drive transmission wire rope according to an embodiment of the present invention.

FIG. 2 is a perspective view of the image reading apparatus.

FIG. 3 is a cross-sectional view of the belt main body before coating with a coating resin layer.

FIG. 4A is a diagram showing an S-twisted rope main body. (B) is a figure which shows the rope main body which carried out the Z twist.

FIG. 5 is a cross-sectional view of a belt main body covered with a coating resin layer.

FIG. 6 is a cross-sectional view of a belt main body covered with a coating resin layer according to another embodiment.

FIG. 7 is a cross-sectional view of a belt main body covered with a coating resin layer according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 Document 32,34 1st, 2nd carriage 41 Motor (drive source) 43-45 Pulley 46a Element wire 46b, 46c Strand 46L, 46R Rope main body 46 Driving force transmission wire rope 5, 7, 8 Coating Resin layer (resin layer) 61L, 61R Rope body 61a Element wire 61b, 61c Strand 62 Metal plating

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuhiro Ono 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Hisashi Yamanaka 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka F term (reference) 2H108 AA01 CB01 DA06 FB62 3B153 AA03 AA08 AA45 CC13 CC22 CC52 FF11 GG40

Claims (4)

[Claims] 1. A driving force transmitting wire rope constituted by a rope body in which strands or strands are twisted, wherein the rope bodies are used in a pair, and the outer peripheral surface of each of the rope bodies is A wire rope for driving force transmission, wherein the wire rope is made of the same base material and covered with resin layers having different color tones. 2. A drive transmission wire rope constituted by a rope body in which strands or strands are twisted, wherein the rope bodies are used in pairs, and the strands or strands are formed of the same wire. In addition, the wires or strands are treated with metal plating of different colors, and the outer peripheral surface of each rope body is covered with a transparent resin layer made of the same base material. The driving force transmission wire rope. 3. A carriage on which an optical system for main scanning of image information of a document is mounted, a driving force transmitting wire rope for moving the carriage in the sub-scanning direction, and each driving force transmitting wire rope. A pulley that drives the pulleys to rotate, and a drive source that drives the pulleys to rotate. The driving force transmission wire rope is constituted by a pair of rope bodies in which strands or strands are twisted. An image reading apparatus using a wire rope for transmitting a driving force, wherein each outer peripheral surface of the rope body is covered with a resin layer made of the same base material and having a different color tone. 4. A carriage equipped with an optical system for main scanning of image information of a document, a driving force transmitting wire rope for moving the carriage in the sub-scanning direction, and each driving force transmitting wire rope. A pulley that rotates and drives the pulley, and a drive source that rotationally drives each of the pulleys. The driving force transmission wire rope is configured by a pair of rope bodies in which strands or strands of the same wire are twisted, The wires or strands of the pair of rope bodies are treated by metal plating of different colors from each other, and the outer peripheral surface of each of the rope bodies is covered with a transparent resin layer made of the same base material. An image reading apparatus using a driving force transmission wire rope.