JPH063750A - Image reader - Google Patents

Abstract

PURPOSE:To move first and second optical elements without vibrating them at the time of reading an image and simultaneously, to prevent the first and second optical elements from being seen over a contact glass at the time of setting an original on the contact glass. CONSTITUTION:In an end part inside a main body case, a position where the first and second optical elements 8 and 9 are closest, is set as an initial position to start the reading of the image. Moreover, first and second driving pulleys 22 and 24 transmitting driving force in a direction where these first and second optical elements 8 and 9 are pulled ahead in the travelling directions of the first and second optical elements 8 and 9 at the time of reading the image, are provided.

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 for reading an image by reciprocating a first optical element and a second optical element in the same direction at a speed ratio of 2: 1.

[0002]

2. Description of the Related Art Conventionally, a structure for reciprocating a first optical element and a second optical element in the same direction at a speed ratio of 2: 1 in the above-mentioned image reading apparatus is shown in FIGS. There is.

First, in the image reading apparatus shown in FIG. 4, a pair of first drive pulleys 2 and a pair of second drive pulleys 3 which are driven by a motor 1 and rotate integrally, are provided coaxially. A pair of first driven pulleys 4 and a pair of second driven pulleys 5 are provided at positions facing the first drive pulley 2 and the second drive pulley 3. Furthermore, a pair of first timing belts 6 wound between the first drive pulley 2 and the first driven pulley 4, and a pair wound between the second drive pulley 3 and the second driven pulley 5. Second timing belt 7 is provided, the ends of the first optical element 8 are connected to the pair of first timing belts 6 one by one, and the pair of second timing belts 7 has an end of the second optical element 9. The parts are connected on one side.

Here, the first timing belt 6 and the second timing belt 7 are driven by driving the motor 1.
Are driven to rotate, and the first optical element 8 and the second optical element 9 reciprocate in the same direction. The tooth number ratio between the first drive pulley 4 and the second drive pulley 3 is set to 2: 1, and the first optical element 8 and the second optical element 9 reciprocate at a speed ratio of 2: 1. To do. Further, the illustrated state is a state of the initial position where the first optical element 8 and the second optical element 9 are closest to each other, and the first optical element 8 and the second optical element 9 are respectively from the initial position when reading an image. Proceed in the direction of arrow A.

Next, in the image reading apparatus shown in FIG. 5, a pair of first drive pulleys 10 driven by the motor 1 are provided, and between the first drive pulley 10 and the first driven pulley 11 is provided. The first timing belt 6 is wound around. Further, a pair of second drive pulleys 12 that rotate integrally with the first driven pulley 11 are provided coaxially with the first driven pulley 11 and between the second drive pulley 12 and the second driven pulley 13. The second timing belt 7 is wound around. It should be noted that the pair of first timing belts 6 are connected to the ends of the first optical element 8 on one side, and the pair of second timing belts 7 are connected to the end of the second optical element 9 on each side.

Here, the first timing belt 6 and the second timing belt 7 are rotationally driven by driving the motor 1, and the first optical element 8 and the second optical element 9 are also driven.
And are reciprocally driven in the same direction. The tooth ratio between the first driven pulley 11 and the second drive pulley 12 is set to 2: 1, and the first optical element 8 and the second optical element 9 are 2: 1.
It reciprocates at a speed ratio of. Further, the illustrated state is a state of the initial position where the first optical element 8 and the second optical element 9 are closest to each other, and the first optical element 8 and the second optical element 9 are respectively from the initial position when reading an image. Proceed in the direction of arrow A.

Next, in the image reading apparatus shown in FIG. 6, a pair of first drive pulleys 14 and a pair of second drive pulleys 15 which are driven by the motor 1 and rotate integrally, are provided coaxially. A pair of first driven pulleys 16 and a pair of second driven pulleys 17 are provided at positions facing the first driving pulley 14 and the second driving pulley 15. Further, the first drive pulley 14 and the first driven pulley 16
A pair of first timing belts 6 wound between
A pair of second timing belts 7 wound around the second drive pulley 15 and the second driven pulley 17 are provided, and the pair of first timing belts 6 has an end portion of the first optical element 8 on one side. The end portions of the second optical elements 9 are connected to the pair of second timing belts 7 one by one.

Here, by driving the motor 1, the first timing belt 6 and the second timing belt 7 are rotationally driven, and the first optical element 8 and the second optical element 9 are also driven.
And are reciprocated in the same direction. The first drive pulley 4
And the second drive pulley 3 has a tooth ratio set to 2: 1, and the first optical element 8 and the second optical element 9 reciprocate at a speed ratio of 2: 1. The illustrated state is the first optical element 8
And the second optical element 9 are in the state of the initial position where they are most separated from each other, and at the time of image reading, the first optical element 8 and the second optical element 9 advance from the initial position in the arrow A direction.

[0009]

In the image reading apparatus shown in FIG. 4, the first drive pulley 2 is disposed on the rear side in the traveling direction of the first optical element 8 at the time of image reading. The second drive pulley 3 is disposed on the rear side in the traveling direction of the second optical element 9 at the time. Therefore, the driving force for moving the first and second optical elements 8 and 9 for image reading is transmitted in the direction of pushing out the first and second optical elements 8 and 9. Then, minute vibrations are generated in the first and second optical elements 8 and 9, and scanning during image reading becomes unstable,
There is a drawback that image quality is degraded due to image fluctuation and pixel shift.

In the image reading apparatus shown in FIG. 5, since the first drive pulley 10 is disposed on the front side in the traveling direction of the first optical element 8 at the time of image reading, the first optical pulley 10 is used for image reading. The driving force for moving the element 8 is transmitted in the direction in which the first optical element 8 is pulled, and the generation of minute vibrations in the first optical element 8 is prevented. However, the second drive pulley 12 is disposed on the rear side in the traveling direction of the second optical element 9 during image reading, and the driving force for moving the second optical element 9 is transmitted in the direction of pushing out the second optical element 9. ,
The second optical element 9 has a drawback that minute vibrations occur, scanning becomes unstable during image reading, image fluctuations and pixel shifts occur, and image quality deteriorates.

In the image reading apparatus shown in FIG. 6, first and second drive pulleys 14 and 15 are arranged on the front side in the traveling direction of the first and second optical elements 8 and 9 during image reading. The driving force for moving the first and second optical elements 8 and 9 for image reading is transmitted in the direction of pulling the first and second optical elements 8 and 9. For this reason, the occurrence of minute vibrations in the first and second optical elements 8 and 9 is prevented, the scanning during image reading is stabilized, and image fluctuation and pixel shift are prevented. However, the position where the first optical element 8 and the second optical element 9 are most distant from each other is set as the initial position, and when the document is set, the second optical element 9 is placed over the transparent contact glass (not shown). It is not visible because it is visible.

It should be noted that after returning the second optical element 9 to the initial position shown in the figure after one image reading is completed, the second optical element 9 may be further moved to a standby position close to the first optical element 8. It is conceivable that the structure for moving the second optical element 9 becomes complicated, and it takes time to move the second optical element 9 to the standby position for each reading operation, so that the image reading operation is performed. Has the drawback of being slow.

[0013]

A pair of a first driving pulley, a first driven pulley, a second driving pulley and a second driven pulley are provided below a contact glass in a main body case, and the first driving pulley and the first driving pulley are connected to each other. A first optical element is connected to a pair of first timing belts wound between the first driven pulley and a pair of first timing belts wound between the second drive pulley and the second driven pulley. The second optical element is connected to the two timing belts, and the first drive pulley and the second drive pulley are rotationally driven to move the first optical element and the second optical element at a speed ratio of 2: 1. In an image reading device that reciprocates in the same direction to read an image,
A position where the first optical element and the second optical element are closest to each other at an end portion inside the main body case is set as an initial position for starting image reading, and the first optical element and the second The first drive pulley and the second drive pulley are arranged on the front side in the traveling direction of the optical element.

[0014]

When the image is read, the first and second timing belts are rotationally driven by the driving of the first and second drive pulleys, and the first optical element and the second optical element are in the same direction at a speed ratio of 2: 1. Move to. Here, since the first and second drive pulleys are arranged on the front side in the traveling direction of the first and second optical elements, the driving force for moving the first and second optical elements during image reading is the first. Since it is transmitted in the direction in which the second optical element is pulled, generation of minute vibrations of the first and second optical elements during image reading is prevented. Moreover, since the first and second optical elements start reading the image with the closest position at the end of the main body case as the initial position, the first optical element and the second optical element are set through the contact glass when setting the original. Is not visible and the appearance is not impaired.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. A main body case 19 having a contact glass 18 attached thereto is provided in the upper part, and in the main body case 19, a first drive shaft 20 and a second drive shaft 21 are arranged with parallel axes, and A pair of first drive pulley 22 and a reduction pulley 23 are fixed to the shaft 20, and a pair of second drive pulley 24 and a reduction pulley 25 are fixed to the second drive shaft 21. Then, the motor pulley 26 a and the reduction pulley 23 fixed to the motor shaft 1 a of the motor 1
A timing belt 27 is wound between the motor pulley 26b and the reduction pulley 25 fixed to the motor shaft 1a.
A timing belt 28 is wound between and.

A pair of first driven pulleys 29 are provided at positions facing the first driving pulley 22, and a pair of second driven pulleys 3 are positioned at positions facing the second driving pulley 24.
0 is provided. The first timing belt 6 is wound between the first drive pulley 22 and the first driven pulley 29, and the second timing belt 7 is wound between the second drive pulley 24 and the second driven pulley 30. Has been done. In addition,
The first drive pulley 22 and the first driven pulley 29 have the same number of teeth, and the second drive pulley 24 and the second driven pulley 30 have the same number of teeth.
The ratio of the number of teeth of the second drive pulley 24 to that of the second drive pulley 24 is set to 2: 1. In addition, the motor pulley 26a and the motor pulley 26
The number of teeth of b and the number of teeth of the reduction pulley 23 and the reduction pulley 25 are set to be equal. Further, the ends of the first optical element 8 are connected to the pair of first timing belts 6 side by side, and the ends of the second optical element 9 are connected to the pair of second timing belts 7 side by side.

Here, FIGS. 1 and 2 (a) show a state in which the first optical element 8 and the second optical element 9 are located at the closest initial positions at the ends in the main body case 19. At the time of image reading, the first and second optical elements 8 and 9 move from this initial position in the direction of arrow A at a speed ratio of 2: 1. The first drive pulley 22 and the second drive pulley 24 are the first and second optical elements 8 during image reading,
9 is disposed on the front side in the traveling direction.

Next, as shown in FIG. 2, the first optical element 8 illuminates an original document (not shown) placed on the contact glass 18 and a lamp 31 for reflecting the reflected light from the original document. The second optical element 9 is formed by one mirror 32 and the second mirror 33 and the third mirror 34 which further reflect the reflected light. Then, this reflected light is reflected by the CCD (Charge Coupled) on the front side in the traveling direction of the reflected light reflected by the third mirror 34.
Device) Lens 3 for forming an image on photoelectric conversion means such as 35
6 is provided.

In such a structure, FIG. 1 and FIG.
(A) shows a state in which the first and second optical elements 8 and 9 are located at the closest initial positions at the end portions in the main body case 19, and by driving the motor 1 from this state, The first and second timing belts 6 and 7 are rotationally driven, the first and second optical elements 8 and 9 both move in the direction of arrow A, and the first drive pulley 22 and the second drive pulley 2
With the tooth number ratio of 4, the document is moved at a speed ratio of 2: 1 and the document placed on the contact glass 18 is read. FIG. 2B shows a state in which one reading is completed,
The first optical element 8 and the second optical element 9 are most distant from each other. Then, by rotating the motor 1 in the reverse direction from this state, the first and second optical elements 8 and 9 return to the initial positions in FIG.

Here, the first and second drive pulleys 22, 24
Is disposed on the front side in the traveling direction of the first and second optical elements 8 and 9 during image reading, and the driving force for moving the first and second optical elements 8 and 9 for image reading is the first. It is transmitted in the direction of pulling the first and second optical elements 8 and 9. Therefore, minute vibrations of the first and second optical elements 8 and 9 at the time of image reading are prevented, scanning at the time of image reading is stabilized, image fluctuation and pixel shift are prevented, and image quality is improved. To do. In addition, since the first optical element 8 and the second optical element 9 are the closest to each other even at the end of the main body case 19 as the initial position, the contact glass is set when the document is set on the contact glass 18. The second optical element 9 is not visible through 18, and the appearance is not damaged.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those described in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the pulley 37 is fixed on the first drive shaft 20, and the pulley 38 is fixed on the second drive shaft 21.
A timing belt 39 for power transmission is wound between 7, 38. Therefore, from the motor 1 to the second drive shaft 21
Power transmission to the pulleys 37, 38 and the timing belt 3
The second drive pulley 24 fixed to the second drive shaft 21 is driven to rotate.

Here, at the time of image reading, the first and second optical elements 8 and 9 move from the illustrated initial position in the direction of arrow A at a speed ratio of 2: 1, and these first and second optical elements are moved. Since the elements 8 and 9 are pulled by the first and second drive pulleys 22 and 24 disposed on the front side in the traveling direction to move, minute vibrations of the first and second optical elements 8 and 9 during image reading Is prevented, the scanning at the time of reading the image is stabilized, the image fluctuation and the pixel shift are prevented, and the image quality is improved. In addition, since the first optical element 8 and the second optical element 9 are the closest to each other even at the end of the main body case 19 as the initial position, the contact glass is set when the document is set on the contact glass 18. Second optical element 9 through 18
Is not visible and the appearance is not damaged.

[0023]

As described above, according to the present invention, a pair of first and second drive pulleys, a first and second driven pulleys, and a first drive pulley and a first driven pulley are provided below the contact glass in the main body case. A pair of first timing belts wound between the pulleys and a pair of timing belts wound between the second drive pulley and the second driven pulley, and a first optical belt connected to the first timing belts. In an image forming apparatus for reciprocating an element and a second optical element connected to a second timing belt in the same direction at a speed ratio of 2: 1 to read an image, the first optical element and the second optical element during image reading Since the first driving pulley and the second driving pulley are arranged on the front side in the traveling direction of the optical element, the driving force for moving the first and second optical elements at the time of image reading is the first and second optical elements. Tell the direction to pull Therefore, it is possible to prevent the occurrence of minute vibrations of the first and second optical elements during image reading, and stabilize the scanning during image reading to prevent image fluctuations and pixel shifts and improve image quality. Since the initial position is the position where the first optical element and the second optical element are closest to each other even at the end of the main body case, the initial position can be set through the contact glass when setting the original on the contact glass. The first optical element and the second optical element are invisible, and the appearance can be prevented from being impaired.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention, in which (a)
Is a plan view and (b) is a side view.

FIG. 2 shows the structure of the first and second optical elements,
(A) is a state at the start of reading, and (b) is a state at the end of reading.

FIG. 3 shows a second embodiment of the present invention, (a)
Is a plan view and (b) is a side view.

FIG. 4 shows a conventional example, (a) is a plan view,
(B) is a side view.

FIG. 5 shows another conventional example, in which (a) is a plan view,
(B) is a side view.

FIG. 6 shows another conventional example, in which (a) is a plan view,
(B) is a side view.

[Explanation of symbols]

 6 1st timing belt 7 2nd timing belt 8 1st optical element 9 2nd optical element 18 Contact glass 19 Body case 22 1st drive pulley 24 2nd drive pulley 29 1st driven pulley 30 2nd driven pulley

Claims (1)

[Claims] 1. A pair of a first drive pulley, a first driven pulley, a second drive pulley and a second driven pulley are provided below a contact glass in a main body case, and the first drive pulley and the first driven pulley are provided. A first optical element is connected to a pair of first timing belts wound between a pulley and a pair of second timing belts wound between the second drive pulley and the second driven pulley. Connecting the second optical element,
By rotating the first drive pulley and the second drive pulley, the first optical element and the second optical element are reciprocated in the same direction at a speed ratio of 2: 1 to read an image. In the image reading device, a position where the first optical element and the second optical element are closest to each other at an end portion inside the main body case is set as an initial position for starting image reading, and the first optical element is used during image reading. An image reading apparatus, wherein the first drive pulley and the second drive pulley are arranged on the front side in the traveling direction of the element and the second optical element.