JPH05191584A - Picture reader - Google Patents

Abstract

PURPOSE:To prevent various inconveniences due to the uneven tension of a belt from being generated in the reading pictures and to reduce the number of parts by simplifying the holding structure of a driven pulley. CONSTITUTION:A timing belt 38 is extended over between two driving pulleys 36 and driven pulleys 37. A timing belt 40 is extended over between two pulleys 36 and driven pulleys 39. Both ends of first and second travelling bodies 23 and 24 are installed on the timing belt 38 and 40. The two driven pulleys are connected by one connection member 50 and the two driven pulleys 39 are connected by one connection member 51. The connection members 50 and 51 are energized in the direction extending the belt by pulling springs 61 and 62, giving the even tension to the timing belts 38 and 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device provided in a scanner, a facsimile machine, a transfer machine, a copying machine or the like. More specifically, the present invention relates to an image reading device that reads light from a light source onto a document surface, reflects the reflected light into a photoelectric conversion element, and reads an image on the document surface.

[0002]

2. Description of the Related Art Conventionally, in this type of image reading apparatus, for example, a light source of a reading optical system and a plurality of mirrors are mounted on a traveling body, and the traveling body is moved along a document on a contact glass. Then, along with the movement, the light from the light source is applied to the document surface, the reflected light is reflected by a plurality of mirrors, and the reflected light is entered into the photoelectric conversion element to read the image on the document surface.

By the way, in this conventional image reading apparatus,
For example, two traveling bodies are provided, a light source and a part of the mirrors are mounted on the first traveling body, and the remaining mirrors are mounted on the second traveling body, as shown in FIG. The first and second traveling bodies a and b are moved by a simple traveling body drive mechanism. In this traveling body drive mechanism, toothed drive pulleys 2 are fixed to both ends of a drive shaft indicated by reference numeral 1 in the figure. The two drive pulleys 2 are stepped pulleys 2a and 2b each having a tooth ratio of 2: 1. Then, the timing belt 4 is stretched between the large-diameter drive pulley portion 2a on the inner side and the toothed driven pulleys 3 respectively corresponding thereto, and the timing belt 4 is wrapped between the toothed driven pulley 5 corresponding to the small-diameter drive pulley portion 2b on the outer side. Belt 6 is stretched over. Then, both ends of the traveling body a are attached to the timing belts 4 and 4, and both ends of the traveling body b are attached to the timing belts 6 and 6, respectively. Further, a reduction pulley 7 is fixed to the outside of one end of the drive shaft 1, and a timing belt 9 is stretched between the reduction pulley 7 and the motor pulley 8. The motor pulley 8 is fixed to the motor shaft of the motor 10.

Further, the two driven pulleys 3 and 3 are
For example, as shown in FIG. 6, a driven shaft 12 fixed to one end of a holding fitting 11 holds the driven shaft 12 rotatably.
The two driven pulleys 5 and 5 are also rotatably held by the driven shaft 12 fixed to one end of the holding member 11. Holding metal fitting 1
1 is a holding piece 11a and a mounting piece 1 formed by bending a plate material into an L shape.
1b is formed and is slidable. The holding piece 11a is
The other end has a hook portion 11c, and the mounting piece 11b is 2
Two long holes 11d and 11e are formed. Then, the fixed guide pin 13 for guiding the movement of the holding metal fitting 11 is engaged with the one long hole 11d, and the screw 14 is passed through the other long hole 11e. Then, the other end of the tension spring 16 whose one end is hooked on the fixed hook 15 is hooked on the hook portion 11c of the holding metal fitting 11. Then, the holding metal fitting 11 is urged in the belt-engaging direction shown by the arrow in the drawing to apply tension to the timing belts 4 and 6, respectively. Then, the screw 14 is tightened to fix the holding metal fitting 11.

Therefore, at the time of image reading, the motor 10 is driven to rotate the timing belt 9 to rotate the drive shaft 1. Then, the drive pulley 2 is rotated to rotate the timing belts 4 and 6 to move the first and second traveling bodies a and b. At that time, the original on the contact glass was read by the reading optical system while traveling the first traveling body a at a speed twice as fast as that of the second traveling body b and keeping the optical path length constant.

[0006]

However, in this conventional image reading apparatus, four driven pulleys 3 and 5 are biased by separate tension springs 15 to apply tension to the timing belts 4 and 6. However, each driven pulley 3
It is difficult to urge 5 with the spring 15 with a uniform spring force. Therefore, there is a problem in that it is not possible to apply a uniform tension to each of the timing belts 4 and 6 due to the variation in the spring force. It was As a result, at the time of image reading, the traveling bodies a and b travel obliquely to distort the read image, the optical path length deviates to the left and right in the reading direction, and the read image becomes uneven. Various problems have occurred, such as vibration and shaking of the scanned image.

Further, the driven pulleys 3 and 5 are attached to the holding metal fittings 11
However, the structure is complicated and the number of parts is increased.

Therefore, an object of the present invention is to prevent various problems in the read image due to the uneven tension of the belt in the above-mentioned image reading apparatus and to simplify the structure for holding the driven pulley. To reduce the number of parts.

[0009]

Therefore, what is stated in claim 1 is, for example, as shown in the following illustrated embodiment,
Two drive pulleys 36 are fixed to one drive shaft 35, and driven pulleys 37 corresponding to those drive pulleys 36,
Belts such as timing belts 38 and 40 are respectively stretched between 39, and both ends of a traveling body such as the first and second traveling bodies 23 and 24 are attached to these belts, and a reading optical system is mounted on the traveling body. A part or all of A is rotated, the drive shaft 35 is rotated to rotate the drive pulley 36, and the belt is driven to move the traveling body to the contact glass 22.
In the image reading device that moves along the path and reads the original 21 on the contact glass 22 by the reading optical system A, the two driven pulleys 37 are connected by one connecting member 50, and the two driven pulleys 37 are connected together. Driven pulley 39/39
Are connected by one connecting member 51, and the connecting members 50.5
1 is urged in the belt running direction by an urging member such as tension springs 61 and 62 to apply tension to the belt and the connecting member 5 in the belt running direction.
It is characterized in that the movement of 0.51 is guided by guides such as guide pins 55 and 56.

According to a second aspect of the present invention, for example, as shown in the following illustrated embodiment, in the image reading apparatus of the first aspect, the connecting members 50 and 51 have elongated holes 50e and 5e.
1e is opened, and the connecting member 50.5 is guided by guides such as guide pins 55 and 56 that engage with the long holes 50e and 51e.
It is characterized by guiding the movement of 1.

According to a third aspect of the present invention, for example, as shown in the following illustrated embodiment, in the image reading apparatus according to the first aspect, the two traveling bodies are provided and the first traveling body 23 is provided.
Is moved twice as much as the second traveling body 24, and all or part of the reading optical system A is separately provided on the first and second traveling bodies 23 and 24.

[0012]

The connecting members 50 and 51 are urged by the urging member in the belt-placing direction, and the connecting members 50 and 51 are moved by being guided by the guides so that uniform tension is applied to the belt.

According to the second aspect of the invention, the movement of the connecting members 50 and 51 is guided by the guides that engage with the elongated holes 50e and 51e.

According to the third aspect, at the time of image reading,
The original 21 on the contact glass 22 is read by the reading optical system A while the first traveling body 23 is moved twice as much as the second traveling body 24 to keep the optical path length constant.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is an overall schematic configuration diagram of an image reading apparatus according to an embodiment of the present invention. Reference numeral 20 indicates the apparatus main body. A contact glass 22 for setting a document 21 is provided on the upper surface of the apparatus body 20. Device body 20
A first traveling body 23 and a second traveling body 24 are arranged in the inside so as to be movable in parallel with the contact glass 22.

A light source 26 and a first mirror 27 of the reading optical system A are mounted on the first traveling body 23. The second traveling body 24 has a second mirror that reflects the reflected light of the first mirror-27.
The mirror 28 and the third mirror 29 that reflects the reflected light of the second mirror 28 are mounted. An optical imaging lens 30 that converges the reflected light from the third mirror 29 and forms an image is provided on the optical path of the reflected light of the third mirror 29 in the apparatus body 20. A photoelectric conversion element 31 for reading the image is provided at the image forming position of the optical image forming lens 30.

By the way, the first and second traveling bodies 23,
24 is driven by the traveling body drive mechanism shown in FIG. In the apparatus body 20, toothed drive pulleys 36 are fixed to both ends of a drive shaft indicated by reference numeral 35 in the figure. The two drive pulleys 36 are stepped pulleys 36a each having a tooth ratio of 2: 1.
・ It consists of 36b. Then, the inner large-diameter drive pulley portion 3
6a and the toothed driven pulleys 37 corresponding to the respective timing belts 38, and the toothed driven pulleys 3 corresponding to the outer small-diameter drive pulley portions 36b.
The timing belt 40 is stretched between 9 points. Then, both ends of the first traveling body 23 are attached to the timing belt 38, and the second traveling body 24 is attached to the timing belt 40.
Attach both ends of. Also, on the outside of one end of the drive shaft 35,
The deceleration pulley 41 is fixed, and the timing belt 43 is stretched between the deceleration pulley 41 and the motor pulley 42. The motor pulley 42 is fixed to the motor shaft of the motor 44.

Further, in the above-mentioned image reading apparatus, FIG.
As shown in, the two driven pulleys 37 on one side are connected by one connecting member 50 and the two driven pulleys 39 on the other side are also connected by one connecting member 51. As shown in detail in FIG. 2, the connecting members 50 and 51 are each made of a long plate material, and both ends of the supporting plate portions 50a and 51a are bent upward to form bent portions 50b and 51b. The support plate portions 50a and 51a are formed with hook portions 50c and 51c, respectively, which are bent upward from the central side edge. Mounting long holes 50d and 51d are formed in the central portion, and the long holes 5d are provided on both sides of the mounting long holes 50d and 51d.
Open 0e and 51e. Then, in the bent portion 50b,
Each of the pulley shafts 52 is fixed outward, and one driven pulley 37 is rotatably attached to the pulley shaft 52. Further, a pulley shaft 53 is fixed inwardly to each of the bent portions 51b, and the other driven pulley 39 is rotatably attached to the pulley shaft 53. Then, the long hole 50
The fixed guide pins 55 and 56 for guiding the movement of the coupling members 50 and 51 are engaged with the e and 51e, respectively, and the screws 57 and 58 are passed through the mounting elongated holes 50d and 51d. Then, tension springs (biasing members) 61 and 62 each having one end hooked on the fixed hooks 59 and 60 are hooked on the other end of the hook portion 50c.
It hangs on 51c. Then, the tension spring 61 urges the connecting member 50 in the belt spanning direction shown by the arrow in FIG. 1 to apply equal tension to the timing belts 38 on both sides. Further, the tension spring 62 similarly urges the connecting member 51 in the direction of the arrow to apply uniform tension to the timing belts 40 on both sides. After that, the screws 57 and 58 are tightened to fix the connecting members 50 and 51.

In the image reading apparatus described above, when reading an image, the motor 44 is driven to rotate the timing belt 43 and rotate the drive shaft 35. Then, the drive pulley 36 is rotated and the timing belts 38 and 40 are rotated to move the first and second traveling bodies 23 and 24, respectively. At that time, the first and second traveling bodies 23 and 24 move at a speed ratio of 2: 1 while keeping the optical path length constant. Along with the movement, the light from the light source 26 is applied to the document surface of the document 21 on the contact glass 22. Then, the reflected light from the original surface is reflected by the first mirror 27, the second mirror 28, and the third mirror 29 and transmitted through the optical imaging lens 30. Then, as shown in FIG. 3, the image is put in the photoelectric conversion element 31 to form an image, the image on the document surface is read, and the reading is completed.

By the way, in the illustrated embodiment described above, two traveling bodies 23 and 24 are provided, and the first traveling body 23 is moved twice as much as the second traveling body 24, and the first traveling body 23 and the second traveling body 24 are moved. A part of the reading optical system A such as the light source 26 and the second mirror 28 is separately mounted on 23 and 24. However, the present invention can be applied to, for example, an image reading apparatus in which one traveling body is provided and the entire reading optical system is mounted on the traveling body.

In that case, for example, as shown in FIG.
One traveling body 65 is attached to a pair of timing belts 66, and two driven pulleys 67 are connected by one connecting member 68. Then, one spring 69 urges the connecting member 68, and the guide 70 moves to guide the connecting member 68 to apply equal tension to the timing belts 66 on both sides. Then, the timing belt 66 is driven to move the traveling body 65.

[0022]

Therefore, according to the present invention, two driven pulleys are connected by one connecting member, and the connecting members are urged by one urging member to apply uniform tension to the belt. When reading an image, various problems may occur such as distortion of the read image due to diagonal traveling of the running body, unevenness of the read image due to deviation of the optical path length in the left / right direction, and fluctuation of the read image due to vibration of the running body. Can be prevented. Further, since the two driven pulleys are connected by one connecting member, the structure for holding the driven pulleys can be simplified and the number of parts can be reduced.

According to the second aspect of the present invention, it is possible to smoothly guide the movement of the connecting member by forming the elongated hole in the connecting member and using the guide engaged with the elongated hole.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of a main part thereof.

FIG. 3 is an overall schematic configuration diagram of the image reading apparatus in a state after image reading.

FIG. 4 is an overall schematic configuration diagram of the image reading apparatus in a state before image reading.

FIG. 5 is a perspective view of a main part of an image reading apparatus according to another embodiment of the present invention.

FIG. 6 is a perspective view of a driven pulley holding structure in a conventional image reading apparatus.

FIG. 7 is a perspective view of a traveling body drive mechanism of the image reading apparatus.

[Explanation of symbols]

 21 original document 22 contact glass 23 first traveling body (traveling body) 24 second traveling body (traveling body) 35 drive shaft 36 drive pulley 37/39 driven pulley 38/40 timing belt (belt) 50/51 connecting member 50e・ 51e Long hole 55 ・ 56 Guide pin (guide) 61 ・ 62 Tension spring (biasing member) A Reading optical system

Claims (3)

[Claims] 1. Two driving pulleys are fixed to one driving shaft, belts are respectively stretched between the driving pulleys and the corresponding driven pulleys, and both ends of the traveling body are attached to these belts. All or part of the reading optical system is provided above, the drive shaft is rotated to rotate the drive pulley, the belt is driven to move the traveling body along the contact glass, and the reading optical system is used to In an image reading apparatus for reading an original on a contact glass, two driven pulleys are connected by one connecting member, and the connecting member is urged by a biasing member in a belt-engaging direction to apply tension to the belt. At the same time, the image reading device guides the movement of the connecting member in the belt spanning direction. 2. A long hole is formed in the connecting member, and a guide engaging with the long hole guides the movement of the connecting member.
The image reading apparatus according to claim 1. 3. The two traveling bodies are provided, the first traveling body is moved twice as much as the second traveling body, and all or part of the reading optical system is provided on the first and second traveling bodies. The image reading device according to claim 1, wherein the image reading device is separately provided.