JPH08220644A - Scanning system driving mechanism for original rader - Google Patents

Abstract

PURPOSE: To provide a compact and efficient scanning system driving mechanism for an original reader. CONSTITUTION: The stator 15 of a linear motor is arranged and fixed on the lower side of a 1st slider 11 supported by guiding rails 13 and 14 and constitutes a linear motor with a rotor 16 arranged at a position opposed to the stator 15 on the lower surface of the 1st slider 11 so as to drive the 1st slider 11. The movement of the lst slider 11 is transmitted to a 2nd slider 12 through a wire driving mechanism 20, and the 2nd slider 12 is driven at moving speed which is 1/2 of the moving speed of the 1st slider 11. The stator 15 of the linear motor is arranged to penetrate between a 2nd mirror and a 3rd mirror, but it is arranged to be one-sided to a position where it does not intercept the projection optical path of a scanning optical system. Since the 1st slider which is light in weight is driven by the linear motor, the scanning optical system is stably driven with low torque, and the height of the device is restrained so that the device is made compact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading device such as a copying machine, and more particularly to a scanning system driving mechanism in the document reading device.

[0002]

2. Description of the Related Art In a copying machine, facsimile machine or the like, a first mirror linearly driven in the sub-scanning direction under a document table.
And a scanning optical system including a projection lens and the like, a second slider having second and third mirrors, and a second slider is provided for the first slider.
There is a device having a structure for driving in the sub-scanning direction at a speed of / 2.

8 to 10 show an example of a conventional document reading apparatus of this type. FIG. 8 is a front view showing a scanning optical system, and FIG. 9 is a plan view showing the configuration of the document reading apparatus. 1
0 is the front view. In FIGS. 8 to 10, 61
Is a document table, 62 is a document, 63 is a first slider, and is provided with an illumination lamp 64 and a first mirror 65. Further, 66 is a second slider, which is provided with a second mirror 67 and a third mirror 68. 69 is a projection lens, 70 is a fourth mirror, 71
Indicates a photosensitive drum.

A linear motor stator 77 is disposed below guide rails 75 and 76 for guiding the first slider 63 and the second slider 66 in the sub-scanning direction.
6, a linear motor mover 78 is provided at a position facing a linear motor stator 77. Further, a pulley 81 is rotatably provided on one side of the second slider 66, and a wire 84 is stretched between the pulleys 81 and 83 provided on the apparatus main body and the pulley 81. One end of 84 is fixed to one side of the main body of the device by a pin 85, and the pulley 81 is wound around a half, each of the pulleys 82 and 83 is wound around a half, and further, the pulley 81 is wound around a half, and the end thereof is wound. The part is fixed to the main body of the apparatus with a pin 87 via a spring 86. A wire 84 is fixed to one side of the first slider 63 by a clamp 88, and a wire drive mechanism 80 in which the speed ratio of the first slider 63 and the second slider 66 is 1/2 is configured.

When the linear motor is driven to drive the second slider 66, the first slider 63 moves to the right (sub scanning direction) in FIGS. 9 and 10 and is scanned by the first slider 63. The original image is displayed on the second mirror 6 of the second slider 66.
7, third mirror 68, projection lens 69, fourth mirror 70
An image can be formed on the photoconductor drum 71 via.

[0006]

By the way, in the above-mentioned document reading apparatus, if the arrangement of the linear motor, especially the position of the mover provided on the side of the running body is not near the center of gravity of the running body including the moving body, The running body meanders and uneven scanning occurs. In analog type document reading devices, linear mode
Since the projection optical path of the scanning optical system is kicked by the stator of the linear motor depending on the arrangement position of the motor, the linear motor must be arranged outside the projection optical path of the scanning optical system. It was difficult to make the device compact.

[0007]

SUMMARY OF THE INVENTION The present invention is to solve the above problems and includes a first slider and a second slider, each of which includes an optical element, and a first slider and a second slider.
In a scanning system driving mechanism in a document reading apparatus in which both sliders are driven in the sub-scanning direction at a speed of 1: 1/2, a mover of a linear motor is provided on the first slider and a stator of the linear motor is It is characterized in that it is arranged between the second mirror and the third mirror so as not to interfere with the movement locus of the projection lens and outside the projection optical path range of the projection lens.

[0008]

By arranging the stator of the linear motor between the second mirror and the third mirror, the first slider, which is lighter than the second slider, can be driven, so that the scanning optical system can be lowered. It can be stably driven by torque, and the device can be made compact.

[0009]

Embodiments of the present invention will be described below.
FIG. 1 is a plan view of a copying machine equipped with the document reading device of the present invention, and FIG. 2 is a sectional view taken along the line AA. Figure 1,
In FIG. 2, 11 is a first slider and 12 is a second slider. Reference numerals 13 and 14 are guide rails for guiding the first slider 11 and the second slider 12 in the sub-scanning direction.
The drive sides (upper side in FIG. 1) of the slider 11 and the second slider 12 are slidably supported by a guide rail 13 by bearings (not shown), and the other ends of the first slider 11 and the second slider 12 slide on each other. The sides are supported so that they slide on the guide rails 14 and slide.

A pulley 21 is rotatably provided on one side of the second slider 12, and the pulleys 22 and 2 are provided on the main body of the apparatus.
A wire 24 is stretched between the pulley 3 and the pulley 21. One end of the wire 24 is fixed to one side of the main body of the device with a pin 25,
The pulley 21 is wound around a half, the pulleys 22 and 23 are wound around a half, respectively, and the pulley 21 is further wound around a half, and an end portion of the pulley 21 is fixed to the apparatus main body by a pin 27 via a spring 26. A clamp 28 is provided on one side of the first slider 11.
Thus, the wire 24 is fixed, and the wire drive mechanism 20 is configured. The diameters of the pulleys 21, 22, and 23 are set so that the second slider 12 moves at 1/2 the moving speed of the first slider 11.

With this structure, the movement of the first slider 11 is transmitted to the second slider 12 via the wire 24 and the pulley 21, and the second slider 12 is 1/2 the moving speed of the first slider 11. Move at the moving speed of.

A linear motor stator 15 is fixedly arranged on the main body of the apparatus below the first slider 11, while a lower surface of the first slider 11 is located at a position facing the linear motor stator 15. A mover 16 of a linear motor is provided. In FIG. 1, the stator 15 of the linear motor is drawn larger than the surrounding constituent members for convenience of description, but it is actually narrower.

The first slider 11 is constructed so that its center of gravity is located near the center line of the stator 15 of the linear motor. By configuring the center of gravity of the first slider 11 to be located near the center line of the stator 15, the linear motor
When the first slider 11 is driven by the slider, no rotational moment is generated due to a gear gap between the first slider 11 and the guide rail 13 and the deterioration of the original reading accuracy due to the swinging motion is prevented. be able to.

FIG. 3 is a sectional view taken along the line BB of FIG.
The ramp 30 and the first mirror 31 provided on the first slider 11 and the second mirror-3 provided on the second slider 12.
The second and third mirrors 33, the projection lens 34, and the linear motor
It is a figure which shows arrangement | positioning of the stator 15 of a rotor. The stator 15 of the linear motor is located below the first slider 11, and the stator 15 is arranged so as to pass through the middle of the second mirror 32 and the third mirror 33 of the second slider 12, The projection lens 34 is arranged below the stator 15 of the linear motor.

The original image illuminated by the lamp 30 is the first
The image is formed on the photoconductor 36 through the mirror 31, the second mirror 32, the third mirror 33, the projection lens 34, and the fourth mirror 35, and image processing is performed by a known electrophotographic method.

Further, in this embodiment, the linear motor which is the drive source of the first slider 11 is used as a structure for moving the projection lens 34 for changing the projection magnification in the optical axis direction.

This structure will be described with reference to FIGS. A linear motor mover 18 is provided at a position of the holding frame 19 of the projection lens 34 facing the stator 15 of the linear motor. In this case, the stator 15 of the linear motor
A magnetic pole for driving the first slider 11 and a magnetic pole for driving the projection lens 34 are separately provided, and the mover 16 of the first slider 11, the mover 18 of the holding frame 19 of the projection lens, and the stator 15 respectively. It is provided at a position facing the magnetic pole.

For driving the linear motor, a known linear pulse motor or linear DC motor driving means can be used. Since the driving means is a known means, its explanation is omitted here.

In FIG. 3, at first glance, it seems that the stator 15 of the linear motor interrupts the projection optical path of the scanning optical system, but as shown in FIG. Since the projection optical path of the system is arranged in a position that does not block the projection optical path and the vertical width (in FIG. 3) of the projection optical path is narrow due to the slit exposure,
There is no risk of blocking the projection optical path. Below, linear mode
The conditions under which the stator 15 of the rotor does not block the projection optical path of the scanning optical system will be described.

FIG. 4 shows the stator 15 of the linear motor and the second
FIG. 4A is a diagram for explaining the positional relationship between the mirror 32, the third mirror 33, and the projection optical path of the scanning optical system. FIG. 4A is a cross-sectional view seen from the front in the moving direction of the second slider 12, (B) of the figure is a cross-sectional view seen from the side surface.

The shaded area in FIG. 4A shows the range in which the projection optical path fluctuates due to a change in the projection magnification, that is, the range in which the projection optical path exists, and outside the shaded area. Linear motor stator 1 so that it is positioned
The conditions for arranging 5 should be obtained.

FIG. 5 is a diagram for explaining the state when the scanning optical system moves, in which the document G on the document table is moved from the position O1 to the position O2.
When scanning up to, the first mirror 31 moves from position A1 to position A2.
The second mirror 32 moves from position B1 to B2, and the third mirror 33 moves from position C1 to C2.

The stator 15 of the linear motor and the second mirror-3
The optical path between the second and third mirrors 33 is closest to each other because the second mirror 32 is located at the position B2 and the third mirror 33 in FIG.
When the position reaches the position C2, the original is placed with the end of the platen of the copying machine as a reference, and the copy paper is also fed in accordance with this. The position of the lens and the position of the projection optical path are shown in FIG. 6, and when the enlargement magnification is maximum and the reduction magnification is minimum,
The optical path between the second mirror and the third mirror is closest to the stator 15 of the linear motor.

In FIG. 5, the distance O1 A1 (O2 A2)
= A, distance A1 B1 = b, distance B1 C1 (B2 C2) =
c, distance B1 B2 = g, distance A1 A2 = 2g, distance C1
When D = d, the maximum angle of view between the lens optical axis and the end of the optical path when the enlargement magnification is maximum and the reduction magnification is minimum is ω (see FIG. 6).
Then, when the second mirror is at the position B2, the distance O2 B2 between the document surface and the position B2 is O2 B2 = (a + b + 2
g−g) = (a + b + g), and the third mirror is at position C.
When it is 2, the distance O2 C2 between the document surface and the position C2 is O2 C2 = (a + b + 2g-g + c) = (a + b + c +
g).

In FIG. 7, the stator 15 of the linear motor is the second
It is a figure explaining the conditions which do not interrupt | block the optical path between the mirror-32 and the 3rd mirror-33. Referring to FIG. 6 and FIG. 7, the condition that the optical path is not blocked is linearly changed from the lens optical axis at the same magnification.
The distance L1 to the stator 15 will be described.

Assuming that the width of the platen is W, when the second mirror is at the position B2, the distance L2 from the lens optical axis position at the same magnification to the end of the optical path incident on the second mirror is O2. Since the distance between B2 is (a + b + g), it is expressed by the following equation (1).

L2 = W / 2− (a + b + g) tanω ... (1) Therefore, the height (position) of the optical path incident on the second mirror 32 and the stator 15 of the linear motor are as follows. Let p be the distance from the lens optical axis to the stator 15 of the linear motor at the same magnification.
The limit distance L3 to is expressed by the following equation (2).

L3 = W / 2− (a + b + g + p) tan ω (2) In order that the stator 15 does not block the optical path, from the lens optical axis at the same magnification to the stator 15 of the linear motor. Since the distance L1 needs to be larger than the limit distance L3 (L1> L3), the stator 15 of the linear motor has the second mirror 32.
The condition of not blocking the optical path between the third mirror 33 and the third mirror 33 is expressed by the following equation (3).

L1> W / 2− (a + b + g + p) tan ω (3) That is, the stator 1 of the linear motor from the lens optical axis at the same magnification.
If the distance L1 to 5 is only the distance shown in equation (3),
This means that there is no possibility that the stator 15 will block the optical path.

[0030]

As described above, according to the scanning system drive mechanism of the document reading apparatus of the present invention, the projection optical path of the scanning optical system is not blocked by the stator of the linear motor,
Since the stator of the linear motor can be arranged between the second mirror and the third mirror, by driving the first slider, which is lighter than the second slider, by the linear motor,
The scanning optical system can be stably driven with low torque. Since the mover provided on the first slider can be arranged near the position of the center of gravity of the first slider, it is possible to prevent uneven scanning due to meandering of the slider. Further, by arranging the stator of the linear motor between the second mirror and the third mirror, the height of the device can be suppressed, and the entire device can be made compact. Is.

[Brief description of drawings]

FIG. 1 is a plan view of a copying machine equipped with a document reading device of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view taken along the line BB of FIG.

FIG. 4 is a diagram illustrating a positional relationship between a stator of a linear motor, a second mirror, a third mirror, and a projection optical path of a scanning optical system.

FIG. 5 is a diagram illustrating a state when the scanning optical system moves.

FIG. 6 is a diagram showing a position of a projection lens and a position of a projection optical path according to a copy magnification.

FIG. 7 is a diagram illustrating a condition in which the stator of the linear motor does not block the optical path between the second mirror and the third mirror.

FIG. 8 is a front view showing a scanning optical system of a conventional document reading apparatus.

FIG. 9 is a plan view showing the configuration of a conventional document reading apparatus.

FIG. 10 is a front view showing the configuration of a conventional document reading apparatus.

[Explanation of symbols]

 11 1st slider 12 2nd slider 13 and 14 Guide rail 15 Linear motor stator 16 Linear motor mover 18 Linear motor mover 19 Projection lens holding frame 20 Wire drive mechanism 31 1st mirror 32 2nd Mirror 33 Third Mirror 34 Projection Lens 35 Fourth Mirror 36 Photoreceptor

Claims (1)

[Claims] 1. A first slider and a second slider each including an optical element, the first slider and the second slider.
In a scanning system driving mechanism in a document reading apparatus in which both sliders are driven in the sub-scanning direction at a speed of 1: 1/2, a linear motor mover is provided on the first slider, and a linear motor stator is provided on the first slider. A scanning system driving mechanism in a document reading device, characterized in that it is arranged between the second mirror and the third mirror and does not interfere with the movement locus of the projection lens and outside the projection optical path range of the projection lens. .