JPH11331510A - Image scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an image scanner and to enable the proper reading processing of an original image by exactly moving a carriage in a sub scanning direction through a means which can miniaturize the image scanner. SOLUTION: This image scanner is provided with a transparent original placing plate 1, carriage 2 loading a line sensor and guide member 4 extended in the sub scanning direction for guiding this carriage 2 in the sub scanning direction parallel with the original placing plate 1 so as to reciprocate it under the original placing plate 1. In this case, the carriage 2 is provided with a driving mechanism 3 for carriage running for running this carriage 2 by itself so as to reciprocate it along the lengthwise direction of the guide member 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image scanner, and more particularly to an image scanner classified as a flatbed image scanner.

[0002]

2. Description of the Related Art An example of a conventional image scanner is shown in FIG.
Shown in In this image scanner, a carriage 2e is disposed below a horizontally set transparent document placing plate 1e. The carriage 2e is equipped with a light source 95, a plurality of reflection mirrors 96a to 96c, an imaging lens 97, and a line sensor 60e.
The image of the document K set on the surface of the document e can be read by the line sensor 60e. The carriage 2e is reciprocally movable in a horizontal sub-scanning direction indicated by an arrow Na. Therefore, in the image scanner, the image of the document K can be sequentially read line by line by the line sensor 60e in the sub-scanning direction.

Conventionally, as means for moving the carriage 2e in the sub-scanning direction, means using a timing belt 98 has been used. This means
The carriage 2e is connected to a timing belt 98 provided reciprocally in the sub-scanning direction by being wrapped around a pair of timing gears 99a and 99b, and the carriage 2e is pulled and moved by the timing belt 98.

[0004]

However, in the prior art, since the timing belt 98 is used as a means for moving the carriage 2e in the sub-scanning direction, there are the following problems.

First, the weight of the carriage 2e cannot be supported only by the timing belt 98, and the carriage 2e cannot be moved stably along a movement trajectory parallel to the original placing plate 1e. For this reason, conventionally, it is necessary to always provide the guide rail 4e for supporting the weight of the carriage 2e and performing the movement guide. As a result, the mechanism for moving the carriage 2e is a circulation drive mechanism of the timing belt 98. And the guide rail 4e are both required. However, they need to be configured to have a size substantially equal to or larger than the maximum movement stroke of the carriage 2e in the sub-scanning direction. Also,
All of them need to be provided below the original placing plate 1e. As a result, there is a problem that the size of the entire image scanner, especially the size in the height direction of the image scanner, becomes large.

[0006] Second, the timing belt 98 is easily stretched, and the longer the period of use, the greater the tendency of the stretched belt to increase. For this reason, conventionally, the movement position accuracy of the carriage 2e is deteriorated due to the elongation of the timing belt 98, which may hinder the image reading process.

The present invention has been conceived in view of the above circumstances, and is intended to enable the carriage to be accurately moved in the sub-scanning direction by means that can be manufactured in a small size. It is an object of the present invention to reduce the size of an image scanner and perform appropriate reading processing of a document image.

[0008]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

That is, an image scanner according to the present invention comprises a transparent document placing plate, a carriage having a line sensor mounted thereon, and a sub-scanning device which is provided below the document placing plate and is parallel to the document placing plate. A guide member extending in the sub-scanning direction for guiding reciprocally in a direction,
Wherein the carriage is provided with a carriage traveling drive mechanism for self-propelling the carriage so as to reciprocate along the longitudinal direction of the guide member. And

The carriage has a light source for irradiating light to the surface of the original placed on the original placing plate, and receives light reflected from the original so that the line sensor receives the reflected light from the original. A configuration may be adopted in which a lens for forming an image is mounted.

In the present invention, by driving the carriage traveling drive mechanism provided on the carriage, the carriage can be self-propelled along the guide member, whereby the carriage can be moved in parallel with the original placing plate. Can be reciprocated in any sub-scanning direction. Since the carriage traveling drive mechanism is attached to the carriage itself so that the carriage can travel on its own, the carriage traveling drive mechanism is different from a conventional mechanism for circulating the timing belt. Differently, it is not necessary to form the carriage in a large size substantially equal to or larger than the maximum movement stroke of the carriage in the sub-scanning direction.
The mechanism can be configured as a relatively small-sized mechanism in which the overall length, thickness, and the like are not bulky below the document placing plate. As a result, according to the present invention, it is convenient to reduce the size of the entire image scanner, and particularly to reduce the thickness.

Further, in the present invention, since the carriage is self-propelled along the guide member, it is of course possible to move the carriage stably in the sub-scanning direction parallel to the original placing plate. However, unlike the means using a conventional timing belt, it is possible to prevent a problem that the positioning accuracy of the carriage is deteriorated due to the extension of the timing belt. Therefore, the positioning accuracy of the carriage can be improved, and the original image can be read at a high resolution.

Preferably, the guide member is a pair of rack gears provided below the document placing plate at regular intervals in the main scanning direction, and the carriage traveling drive mechanism is provided with the pair of rack gears. It comprises a plurality of pinion gears meshing with the rack gears, respectively, and a motor for applying a rotational driving force to the plurality of pinion gears.

According to such a configuration, the carriage can be properly self-propelled by driving and rotating a plurality of pinion gears meshing with a pair of rack gears as guide members by a motor. May be a plurality of pinion gears and a motor for applying a rotational driving force to the plurality of pinion gears, and the configuration thereof can be extremely simplified, and the size thereof can be reduced. Further, the rotational force of the rack gear can be reliably transmitted to the rack gear, and a slip or the like can be prevented from being generated therebetween, so that the position of the carriage can be more accurately controlled.

Preferably, the apparatus further comprises a pair of auxiliary guide rails extending in the sub-scanning direction below the document placing plate and provided at a predetermined interval in the main scanning direction. A plurality of first rollers for abutting against the lower surface of the document placing plate, a plurality of second rollers for rolling along the pair of auxiliary guide rails, and a plurality of the second rollers. When rolling along the pair of auxiliary guide rails, the plurality of first
An elastic member is provided for urging the carriage upward against the plurality of second rollers so as to maintain the rollers in contact with the lower surface of the document placing plate.

According to such a configuration, when the carriage is self-propelled in the sub-scanning direction, the plurality of second rollers provided on the carriage are rolled along the pair of auxiliary guide rails. As a result, the elastic member elastically urges the carriage upward against the plurality of second rollers,
The first roller is kept in contact with the lower surface of the document placing plate. In other words, the first roller can be constantly brought into contact with the lower surface of the original placing plate during the self-propelled movement of the carriage.
As a result, it is possible to accurately move the carriage in parallel with the original placing plate with the lower surface of the original placing plate as a reference surface, and to maintain a constant gap between the original surface and the carriage. , An appropriate image reading operation can be performed.

[0017] Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a sectional perspective view of a main part showing a schematic configuration of an image scanner according to the present invention. FIG. 2 shows FIG.
3 is an exploded perspective view of main parts of the image scanner shown in FIG. FIG. 3 is a cross-sectional view of a main part, partially omitted from the direction of arrow III in FIG. FIG. 4 is a partial cross-sectional side view from the direction of arrow IV in FIG. FIG. 5 is a sectional view taken along line VV of FIG. FIG. 6 is a sectional view taken along line VI-VI of FIG. FIG. 7 shows VII of FIG.
It is a VII sectional view.

In FIG. 1, this image scanner A
Is configured to include a document placing plate 1, a carriage 2, a pair of pinion gears 30, 30 mounted on the carriage 2, a pair of rack gears 4, 4, and other components to be described later. The carriage 2 extends in the main scanning direction indicated by the arrow N1, but can move in the sub-scanning direction indicated by the arrow N2 by being engaged with each of the pinion gears 30 and the rack gear 4. There is a feature.

The original placing plate 1 is made of, for example, a flat transparent glass plate.
Is set on the upper surface of the document. This original placing plate 1
As best seen in FIGS. 3 and 5, it is fixedly attached to the upper part of a housing 5 having a hollow interior, and is supported horizontally. The housing 5 is configured by combining an upper member 5a and a lower member 5b formed separately from each other. The mounting of the carriage 2 and other predetermined parts into the housing 5 is performed by the above-described method. Member 5a and lower member 5b
And can be performed separately from each other.

The pair of rack gears 4 and 4 are provided below the document placing plate 1 so as to be spaced apart from each other by a predetermined distance in the main scanning direction, and both extend in the horizontal sub-scanning direction. These pair of rack gears 4, 4
It is fixedly attached to elongated base members 50, 50 attached to the lower member 5b of the housing 5. However,
The present invention is not limited to this. For example, rack teeth may be formed directly on the upper surface of each base member 50, and each base member 50 itself may be configured as a rack gear.

The base members 50, 50 constitute a pair of auxiliary guide rails 51, 51. More specifically, a portion of the base members 50, 50 where the rack gears 4, 4 are not attached is a pair of auxiliary guide rails 51, 51. These auxiliary guide rails 51, 51 are portions for guiding the second rollers 24b, 24b attached to the carriage 2 as described later, and the upper surfaces thereof are one step lower than the upper surfaces of the rack gears 4, 4. It is a flat surface of height. The pair of auxiliary guide rails 51, 51
As in the case of No. 4, they are located at a certain distance from each other in the main scanning direction, and all extend in the horizontal sub-scanning direction.

As best shown in FIG. 2, the carriage 2 includes a case 20 and the pair of pinion gears 3.
And a carriage traveling drive mechanism 3 configured to include 0, 30. The carriage 2 includes a circuit board 62 on which a line sensor 60 and an LED light source 61 are mounted, a plurality of attachments 63, a lens array 64, a light guide member 8,
And a reflector 9. However, the means for reading the document image will be described later for convenience, and the configuration for enabling the carriage 2 to move on its own will be described first.

The case 20 is made of a synthetic resin, and has a shape elongated in a certain direction in which a plurality of concave portions described later are formed at appropriate positions. The carriage 2 is provided in this case 20.
And a plurality of components described above.

The carriage traveling drive mechanism 3 includes a pair of pinion gears 30, 30 and a shaft 3 for connecting and supporting the pair of pinion gears 30, 30 with each other.
1, a motor M, and a reduction mechanism 32 for reducing the rotation of the drive shaft of the motor M and transmitting the rotation to the shaft 31. The pair of pinion gears 30, 3
Numerals 0 are provided near both ends in the longitudinal direction of the case 20 so as to mesh with the pair of rack gears 4, 4. The shaft 31 includes a plurality of bracket pieces 21 protruding from one side surface of each of both ends in the longitudinal direction of the case 20.
a through 21c or the bracket pieces 21
It is rotatably supported by, for example, fitting into a U-shaped groove provided in a to 21c. The plurality of bracket pieces 21 a to 21 c may be formed integrally with the case 20, but are not limited thereto, and are configured by attaching a member formed separately from the case 20 to the case 20. You may. This is the same for the protruding portion 22 and the other bracket pieces 21d and 21e described later.

The motor M and the speed reduction mechanism 32 are
0, and a protruding portion 22 provided on one side
It is provided in an accommodating part 22a formed by the cover body 23 which can be attached and detached. 3, the speed reduction mechanism 32 includes, for example, six gears 32a.
To 32f, and the rotational force of the first gear 32a attached to the drive shaft of the motor M
By being sequentially transmitted to the gear 32b, the third gear 32c, the fourth gear 32d, the fifth gear 32e, and the sixth gear 32f, the rotation speed of the drive shaft of the motor M is finally reduced to five stages. It has become. The sixth gear 32f
Is mounted so that it cannot rotate relative to the shaft 31,
Thereby, the driving force of the motor M is transmitted to the shaft 31,
A pair of pinion gears 30 and 30 rotate. The second gear 32b and the fourth gear 32d are rotatable relative to the shaft 31. The third gear 32c
The fifth gear 32e is rotatable relative to the auxiliary shaft 33 supported by the protrusion 22. If the speed reduction mechanism 32 is used, the rotation speed of the pair of pinion gears 30, 30 can be reduced and the rotation torque can be increased by the speed reduction mechanism 32. Therefore, the advantage that a small and inexpensive motor having a small rotational torque can be used as the motor M is obtained.

The case 20 includes a pair of first rollers 24a, 24a provided at both ends in the longitudinal direction of the case 20 as means for assisting the movement of the carriage 2 in the sub-scanning direction. A second roller 24b is also provided. The pair of first rollers 24a, 24a
Is a roller for making contact with the lower surface (back surface) of the document placing plate 1 and is provided so as to protrude above the upper surface of the case 20 and is spaced apart from each other by an appropriate distance in the sub-scanning direction. Away. The pair of first rollers 24
a, 24a is one of the Bukerat pieces 21a,
The shaft is supported rotatably on the upper part of the upper part 21b, and the other part is mounted on the upper part of bracket pieces 21d and 21e projecting from the other side of the longitudinal end of the case 20. Are supported and rotatably mounted.

As best shown in FIG. 4, the second roller 24b is rotatably supported by the tip of the arm 25, and is disposed below the lower surface of the case 20. The arm 25 is connected to the bracket pieces 21b, 21b.
c is supported via a pin 25a, and can swing vertically about the pin 25a. The bottom part 2 of the arm 25 and the bracket pieces 21b and 21c
1 f, a spring 26 for constantly pressing and urging the arm 25 downward is interposed.

The carriage 2 is set so that the pinion gears 30, 30 are mounted on the pair of rack gears 4, 4, and is arranged below the original placing plate 1. Also, the second rollers 2 at both ends in the longitudinal direction of the carriage 2
4b and 24b are the pair of auxiliary guide rails 51 and 5
1, while each pair of first rollers 24
Reference numerals a and 24a are in contact with the lower surfaces of both edges of the original placing plate 1 in the main scanning direction.

In the image scanner A, the weight of the carriage 2 can be supported by the rack gears 4 and 4 via the pinion gears 30 and 30. By rotating the pinion gears 30 and 30 by the driving force of the motor M, The pinion gears 30 and 30 roll thereon while meshing with the rack gears 4 and 4. Therefore, the carriage 2 can be appropriately reciprocated in the sub-scanning direction parallel to the document placing plate 1. in this way,
If the carriage 2 is of a self-propelled type, it is not necessary to provide a large-scale mechanism for moving the carriage 2 around the rack gears 4 and 4, for example.
On the other hand, the carriage traveling drive mechanism 3 for moving the carriage 2 is compactly assembled to the case 20 of the carriage 2. Therefore,
The size of the image scanner A can be reduced.

While the carriage 2 is moving, each second roller 24b rolls along the auxiliary guide rail 51 while being in contact with the upper surface of the auxiliary guide rail 51 by the resilience F of the spring 26. As a reaction, the elastic force F of the spring 26 causes the carriage 2 to move the carriage 2 to the second roller 2.
4b acts as a force for urging upward relative to 4b. Therefore, the pair of first rollers 24 a, 24 a maintain a state of being in contact with the lower surface of the document placing plate 1 and reliably roll along the lower surface of the document placing plate 1. On the other hand, each of the first rollers 24a is attached to the case 20 of the carriage 2 so that the relative positional relationship with the case 20 is constant. Therefore, each of the first rollers 2
When the carriage 4a rolls while being in contact with the lower surface of the original placing plate 1, the carriage 2 accurately moves in parallel with the original placing plate 1, and is placed on the upper surface of the original placing plate 1. The distance between the front surface of the document K and the carriage 2 can be kept constant.

Next, means for reading an original image provided on the carriage 2 will be described.

As is best seen in FIGS. 5 and 6,
The carriage 2 guides the light emitted from the LED light source 61 to irradiate the linear image reading area P on the upper surface of the original placing plate 1 by using the light guide member 8. The light reflected from the surface of the document K placed on the upper surface is focused by the lens array 64 to form a document image on the line sensor 60, and the corresponding image signal is output from the line sensor 60. It is configured to be output.

The LED light source 61 is, for example, an LED chip packaged with a resin. When the image scanner A is used for reading a so-called monochrome image, the LED light source 61 may be a light source that emits monochromatic light of white or any other color. In that case, R, G,
Three types of LEDs that emit light of each color of B, or LEDs that emit white light are used. Even when three types of LEDs are used, the chips of these three LEDs are
It is possible to make it into one package as a light source of a group.

FIG. 8 is a partially cutaway perspective view showing the light guide member 8. FIG. 9 is a sectional view taken along line IX-IX of FIG.
FIG. 10 is an explanatory diagram showing the operation of the light guide member 8.

The light guide member 8 is provided with a transparent member obtained by molding an acrylic transparent resin such as PMMA, and the surface of each part is a mirror surface. As is clearly shown in FIG. 8, the light guide member 8 includes an auxiliary region S at one longitudinal end of the light guide member 8.
b and other main areas Sa. As shown in FIG. 9, the auxiliary area Sb is provided with a light incident surface 82 facing the LED light source 61, tapered surfaces 86a and 86b, and a downward projection 81. When light emitted from the LED light source 61 enters the auxiliary region Sb via the light incident surface 82, the auxiliary region Sb totally reflects the light by the tapered surfaces 86a and 86b, and the main region Sa It is configured to proceed toward. The protrusion 81 is provided on the light incident surface 82.
Helps to secure a space for arranging the LED light source 61 below.

The main region Sa has a uniform cross-sectional shape at various points in the longitudinal direction, and as shown in FIG.
First side surface 80 facing the light guide member 8 in the vertical thickness direction
A and a second side face 80B, and a third side face 80C and a fourth side face 80D facing each other in the left-right width direction of the light guide member 8. These side surfaces 80A to 80D all extend in the longitudinal direction of the light guide member 8. However, as shown in FIG. 9, a plurality of recesses 84 are provided at appropriate intervals in the second side surface 80B. The region between the plurality of recesses 84, 84 is a mirror-like plane. The plurality of recesses 84 are portions that play a role in rapidly changing the traveling angle of light traveling in the light guide member 8, and have, for example, an arc-shaped cross section.

When light travels from the auxiliary region Sb into the main region Sa, the light is transmitted to the first side surface 8.
0A, the third side surface 80C, the fourth side surface 80D, and the flat surface portion of the second side surface 80B while repeating the total reflection, and forming the end surface 8 at one end in the longitudinal direction of the light guide member 8.
It is configured to proceed toward 0E. When light travels inside the light guide member 8 having a mirror-finished surface, the light is applied to the side surface of the light guide member 8 by a predetermined amount specified by the material of the light guide member 8. When the light is incident at an angle larger than the reflection critical angle, the light is totally reflected, and the light can travel inside the light guide member 8 so as not to leak to the outside of the light guide member 8. On the other hand, when the incident angle of light on the side surface of the light guide member 8 is smaller than the critical angle of total reflection, the light beam is transmitted to the outside of the light guide member 8 as it is. In the light guide member 8, light that has traveled to the main area Sa based on such a principle can be made to travel in the longitudinal direction of the main area Sa.

However, when light is incident on the second side surface 80B, most of the light incident on each of the concave portions 84 is reflected in a form close to scattered reflection, and the course of the light is rapidly changed.
Therefore, most of the light reaching the second side surface 80B is
As shown in FIG. 10, the third side surface 80C and the fourth side surface 8
0D, the third side surface 80C and the fourth side surface 80C.
The light is totally reflected by the side surface 80D.
The third side surface 80C and the fourth side surface 80D are configured as paraboloids (secondary curved surfaces) having the center axis C in the width direction of the main region Sa as a common main axis, and the second side surface 80B.
Are located near a common focal point O1 of their paraboloids. For this reason, the second side surface 80B to the third side surface 80B
C and a large number of light rays that have been reflected on the fourth side face 80D travel toward the first side face 80A as a ray bundle substantially parallel to the principal axis of the paraboloid, and pass through the first side face 80A. And emitted to the outside. However, the first side surface 80A is formed in a convex shape. For this reason, the first side surface 80
The light emitted from the light guide member 8 to the outside of the light guide member 8 has a predetermined focus O
2 to be converged. Such light emission is performed at various points along the entire length of the first side surface 80A.

The reflector 9 is for supporting the light guide member 8. The light guide member 8 is supported by the reflector 9 at a fixed angular posture by fitting the main region Sa into a groove 90 having a side opening formed in a series along the longitudinal direction of the reflector 9. Is done. The inner surface of the groove portion 90 is in opposition to each of the second side surface 80B, the third side surface 80C, and the fourth side surface 80D of the light guide member 8, and the light traveling in the light guide member 8 receives It also plays a role in preventing leakage to the outside. As shown in FIG. 5, the reflector 9 has one end 9 a in the longitudinal direction,
Is formed in a shape capable of covering the outer surface of the auxiliary region Sb, and a wall surface 90e capable of covering the end surface 80E of the light guide member 8 is formed on the other end 9b in the longitudinal direction. Therefore, the light emitted from the LED light source 61 and traveling into the auxiliary region Sb leaks out of the auxiliary region Sb, and the light reaching the end face 80E of the light guide member 8 exits the light guide member 8 as it is. Leakage can also be prevented by the reflector 9. The reflector 9 is made of, for example, a white synthetic resin, and a surface facing the light guide member 8 is a smooth surface having a high light reflectance. The reflector 9 is constituted by a single member, but may be constituted by a plurality of members instead of this.

The reflector 9 is fitted into a first concave portion 27a having an open top surface provided on the case 20.
Thus, the light guide member 8 is attached to the case 20 so as to extend in the longitudinal direction of the case 20, that is, in the main scanning direction.

The lens array 64 includes, for example, an original K
A plurality of rod lenses 64a capable of forming an image of the surface of the image at erect equal magnification are held in a synthetic resin holder 64b and arranged in a row. Of course, a lens array in which a plurality of convex lenses are arranged in series may be used instead of the rod lens 64a. The lens array 64 is fitted into a second concave portion 27b having an upper surface opening provided on the upper surface of the case 20, and extends in the main scanning direction. The surface portion of the document placing plate 1 immediately above the lens array 64 is a linear image reading area P.

The line sensor 60 is formed by mounting a plurality of sensor IC chips integrally formed with a plurality of photoelectric conversion elements on the surface of a circuit board 62 in a plurality of rows, for example. When light is received on the light receiving surface of the conversion element, an image signal having an output level corresponding to the amount of received light is output.

The circuit board 62 is in the form of a flat plate made of, for example, ceramic or epoxy resin. As is well shown in FIG. A connector terminal 71 for wiring connection is provided. On the surface of the circuit board 62, a wiring portion (not shown) for electrically connecting the connector terminal 71 and the line sensor 60 is provided, and input of various signals from the outside to the line sensor 60 is provided. The output is performed via the wiring section and the connector terminal 71. The circuit board 62 is fitted into a downwardly opening third recess 27 c provided on the bottom surface of the case 20, and is attached to the bottom surface of the case 20 by attachments 63. Each of the attachments 63 is formed by, for example, press-molding a thin metal plate, and has a structure that can be engaged with the engaging projections 28 projecting from both side surfaces of the case 20. . The circuit board 62 includes the engaging protrusion 2.
8 is pressed upward by the attachment 63 hung on the second concave portion 27c so that the third concave portion 27c
It is fitted and held inside. Thus, the circuit board 62
Is assembled to the case 20, so that the line sensor 60 is disposed immediately below the lens array 64,
The LED light source 61 is located immediately below the light incident surface 82 of the light guide member 8.

In the image scanner A, the image reading area P is moved while the carriage 2 is moved in the sub-scanning direction.
, And the image of the original K can be sequentially read one line at a time. In this case, the light irradiation on the image reading area P extends in the main scanning direction of the light guide member 8 while causing the light emitted from the LED light source 61 to travel in the main scanning direction inside the light guide member 8. Since the light is emitted from the entire length area of the first side surface 80A, it is not necessary to use a large number of LED light sources as a means for irradiating the linear image reading area P with light. Further, since the light guide member 8 can focus the light emitted from the first side surface 80A to a predetermined focal point O2, the light emitted from the first side surface 80A is narrower than the image reading area P. Irradiation can be intensively performed with a small dimension L (see FIG. 6). That is, it is possible to efficiently irradiate the image reading area P without dispersing much of the light emitted from the first side surface 80A in various directions. Therefore, even if the number of LED light sources 61 is small,
It is possible to increase the illuminance of the image reading area P,
It is also possible to eliminate the problem that the quality of the read image is deteriorated due to the insufficient light amount of the document illumination. In particular,
Since the light traveling in the light guide member 8 can be prevented from being unduly leaked to the outside of the light guide member 8 from a position other than the first side surface 80A, the light is applied to the image reading area P. Efficiency can be further improved.

The specific configuration of each part of the image scanner according to the present invention is not limited to the above-described embodiment, and various design changes can be made.

In the above-described embodiment, the carriage 2 can move by itself by engaging the rack gear 4 rotated by the motor M with the pinion gear 30.
The specific configuration of the carriage traveling drive mechanism according to the present invention is not limited to this, and the carriage traveling drive mechanism may be configured to be able to travel by itself using another mechanism.

In the above embodiment, a so-called contact type line sensor is used as the line sensor. However, in the present invention, a so-called non-contact type line sensor may be used instead. That is, the carriage is provided with a plurality of mirrors, and the light reflected from the surface of the document in the image reading area is reflected by the plurality of mirrors to increase the optical path length. Alternatively, light may be received by a non-contact type line sensor. Needless to say, the line sensor may be either one corresponding to reading a color image or one corresponding to reading a monochrome image. As the light source, a cold cathode tube, a xenon tube, or the like may be used instead of the LED light source. Since these cold cathode tubes and xenon tubes are white light sources, they are suitable for use in reading color images.

[Brief description of the drawings]

FIG. 1 is a sectional perspective view of a main part showing a schematic configuration of an image scanner according to the present invention.

FIG. 2 is an exploded perspective view of main components of the image scanner shown in FIG.

FIG. 3 is a cross-sectional view of a main part, partially omitted from the direction of arrow III in FIG. 1;

FIG. 4 is a partial cross-sectional side view from the direction of arrow IV in FIG. 1;

FIG. 5 is a sectional view taken along line VV of FIG. 1;

FIG. 6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 5;

FIG. 8 is a partially cutaway perspective view showing a light guide member used in the image scanner shown in FIG.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 8;

FIG. 10 is an explanatory view showing an operation of the light guide member shown in FIGS. 8 and 9;

FIG. 11 is an explanatory diagram illustrating an example of a conventional image scanner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original mounting plate 2 Carriage 3 Carriage drive mechanism 20 Case 24a First roller 24b Second roller 26 Spring (elastic member) 30 Pinion gear 31 Axis 4 Rack gear 5 Housing 8 Light guide member 9 Reflector 32 Reduction mechanism 51 Auxiliary guide Rail 60 Line sensor 61 LED light source 62 Circuit board 63 Lens array A Image scanner K Document P Image reading area M Motor

Claims (4)

[Claims] 1. A carriage on which a transparent original placing plate, a line sensor is mounted, and a carriage which is guided below the original placing plate so as to reciprocate in a sub-scanning direction parallel to the original placing plate. And a guide member extending in a sub-scanning direction for moving the carriage in such a manner that the carriage can reciprocate along the longitudinal direction of the guide member. An image scanner provided with a driving mechanism for the image. 2. The guide member is a pair of rack gears provided at a predetermined interval in a main scanning direction below the document placing plate, and the carriage traveling drive mechanism is a pair of the rack gears. 2. The image scanner according to claim 1, further comprising a plurality of pinion gears meshing with the rack gears, and a motor for applying a rotational driving force to the plurality of pinion gears. And a pair of auxiliary guide rails extending in the sub-scanning direction below the document placing plate and provided at regular intervals in the main scanning direction. A plurality of first rollers for making contact with the lower surface of the document placing plate, a plurality of second rollers for rolling along the pair of auxiliary guide rails, and the plurality of second rollers The carriage is attached to the plurality of second rollers upward so as to maintain the plurality of first rollers in contact with the lower surface of the document placing plate when rolling along the pair of auxiliary guide rails. The image scanner according to claim 2, further comprising a biasing elastic member. 4. A light source for irradiating light to a surface of a document placed on the document placing plate, and a light reflected by the document to the line sensor. 4. The image scanner according to claim 1, further comprising a lens for forming an image of a document.