JPH10164325A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate high-speed read, to compact a device case body and to provide high image quality even in halftone original read by arranging a light source and a photodetector so as to almost parallelize an irradiation light path and a reflection light path. SOLUTION: A fixed light source is arranged near the photodetector so as to parallelize an optical path from the light source to a read surface and the optical path from the read surface to the photodetector. That is, the light source 1 is fixed to the device case body 15 and a relative position with the device case body 15 is not changed. Thus, since the light source is not loaded to a moving unit 4, the mass of the moving unit 4 is not enlarged, a cable is not hooked and the high-speed read is facilitated. When the moving units 4 and 5 are moved in a direction Y Which is a sub-scanning direction, since the light source 1 is arranged near a linear CCD 3 and the optical path from the light source 1 to the read surface M and the optical path from the read surface M to the linear CCD 3 are parallel, it is not necessary to move the light source 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and more particularly, to an image reading apparatus such as a copying machine, a facsimile machine, and an image scanner.

[0002]

2. Description of the Related Art Generally, a copying machine reads an original placed on a reading surface glass and copies the read image onto paper.

A facsimile apparatus reads an original or the like placed on a reading surface glass, and transmits the read image image to another facsimile apparatus via a telephone line or the like. This facsimile machine usually also has the function of a copying machine.

Further, the image scanner converts an original placed on the reading surface glass into image data and outputs the image data.

Each of the above image reading apparatuses has an image reading mechanism for reading an original placed on a reading surface glass. An image reading mechanism in the conventional image reading apparatus will be described with reference to the drawings.

FIG. 7 is a diagram showing a configuration of an image reading mechanism in a conventional image reading apparatus. In FIG. 1, the conventional image reading apparatus has a configuration in which two moving units 4 and 5 are provided in a housing 15. The housing 15 includes a driving pulley 6, a wire 10 driven by the driving pulley 6, and a driven pulley 7 for guiding the wire 10. 5 is driven to move in the sub-scanning direction.

A one-dimensional CCD (Charge Co.) for receiving light reflected from an original (not shown) is provided in the housing 15.
and a lens 2 that collects reflected light on the CCD 3. The light source 26 provided in the moving unit 4
Is reflected from the original, and is reflected by a mirror 8 provided on the moving unit 4 and two mirrors 9 provided on the moving unit 5. The light reflected by these mirrors is condensed on a one-dimensional CCD 3 by a lens 2 and received and converted into an electric signal.

The operation of the image reading apparatus having the above configuration will be described with reference to FIG. As shown in the figure, the moving units 4 and 5 are driven by a driving pulley 6, a driven pulley 7, and a wire 10 in the arrow Y direction which is the sub-scanning direction. As a result, the moving units 4 and 5 move from the position shown by the solid line in the figure to the positions 4 'and 5' shown by the broken line.

At the time of this movement, light from a light source 26 provided in the moving unit 4 irradiates a reading surface M on which a document or the like to be read is placed. Then, the reflected light from the reading surface M enters the lens 2 via the mirror 8 of the moving unit 4 and the mirror 9 of the moving unit 5. The reflected light from the reading surface M condensed by the lens 2 is received by the one-dimensional CCD 3 and converted into an electric signal. The reading line at this time is R in the figure. In this case, the read line of sight R corresponds to each of the read positions A and B on the read surface M.
And a line connecting the lens and the CCD.

As described above, in the present image reading apparatus, a document or the like placed on the reading surface can be read by moving the reading position in the sub-scanning direction.

FIG. 9 is a diagram showing a configuration of an image reading mechanism in another conventional image reading apparatus. In this figure, the same parts as those in FIGS. 7 and 8 are indicated by the same reference numerals,
A detailed description of that part is omitted.

In FIG. 1, another conventional image reading apparatus includes a mirror 14 which rotates about an axis J within a predetermined angle range.
And a lens unit 11 for receiving the light reflected by the mirror 14, a cam 12, and a link 13. The lens unit 11 is a one-dimensional CCD 3
And a lens 2 for collecting the light reflected by the mirror 14 on the CCD 3. Note that a light source 32 having the same length as the document length is provided in the housing 15 at a position where the reading line is not blocked.

The operation of the image reading apparatus having the above configuration will be described with reference to FIG. As shown in the figure, when the cam 12 rotates, the link 13 moves the lens unit 11 within a range from the position shown by the solid line to the position shown by the broken line in the figure. Further, the mirror 13 for the lens unit 11 is linked by the link 13.
The angle of 4 also rotates within the range shown by the broken line from the position shown by the solid line in the figure.

The light radiated from the light source to the reading surface M by this rotation and reflected is incident on the lens 2 via the mirror 14. The reflected light from the reading surface M condensed by the lens 2 is received by the one-dimensional CCD 3 and converted into an electric signal. At this time, the reading position on the reading surface M moves in the direction of arrow Y which is the sub-scanning direction.

Therefore, the reflection angle of the mirror 14 changes due to the rotation, and the reading line for the reading position A on the reading surface M is SA and R in the drawing, and the reading line for the reading position B on the reading surface M is in the drawing. Of the reading position C on the reading surface M are indicated by SC and R in the drawing. The reading line in this case is a line connecting each reading position on the reading surface M with the lens and the CCD.

As described above, the present image reading apparatus can read a document placed on the reading surface by moving the reading position in the sub-scanning direction.

[0017]

The conventional image reading apparatus described above has the following disadvantages.

First, in the image reading apparatus shown in FIGS. 7 and 8, since the light source is mounted on the moving unit, the mass of the entire moving unit increases, and it is difficult to perform a high-speed reading operation. There is a disadvantage that.

Further, since the light source is mounted on the moving unit, the signal line for turning on the light source becomes long, and there is a risk of disconnection or catching. Therefore, high-speed reading operation is performed from this point as well. There is a disadvantage that it is difficult.

Further, since the light source is mounted on the moving unit, the moving unit itself becomes large, and there is a disadvantage that the apparatus housing cannot be made compact.

Next, in the image reading apparatus shown in FIGS. 9 and 10, in addition to the light from the light source illuminating the reading surface, the light reflected by the mirror illuminates the reading surface or the lens unit shades the reading surface. It is difficult to control the brightness of the reading surface, for example, to make it. For this reason, there is a drawback that it is difficult to obtain high image quality when reading a halftone original in which a change in the brightness of the reading surface greatly affects image quality.

Further, a large light source having a length corresponding to the length of the document to be read in the sub-scanning direction, that is, a maximum sub-scanning length is required, and a plurality of light sources are required to illuminate the entire area. Therefore, there is a disadvantage that the price of the light source is high and the price of the entire device is high.

Further, the light source must be arranged at a position where it does not block the line of sight of the reading, and the light source having the same length as the document must be mounted. is there.

Japanese Utility Model Application Laid-Open No. 5-1566 discloses a mechanism in which a light source and a light receiving element are mounted on a head carriage, and the head carriage is opposed to a platen roller to read an image. However, even in such a mechanism, since the light source and the light receiving element move, there is a risk that the signal line is disconnected or caught, and there is a disadvantage that it is difficult to perform high-speed reading.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and has as its object to facilitate high-speed reading, to have a compact apparatus housing, and to obtain high image quality even when reading halftone originals. It is an object of the present invention to provide a low-cost image reading apparatus that can perform the above-mentioned operations.

[0026]

According to the present invention, there is provided an image reading apparatus comprising: a fixed light source; and a light receiving element for irradiating a light from the light source to a reading target and receiving reflected light from the reading target. The apparatus is characterized in that the light source and the light receiving element are arranged such that an optical path from the light source to the reading target and an optical path from the reading target to the light receiving element are substantially parallel. The light receiving element is arranged near the light source. Further, it also includes a reflector or the like for condensing the light from the light source on the object to be read with directivity.

In short, in the present image reading apparatus, the fixed light source and the light receiving element are arranged such that the optical path from the light source to the object to be read and the optical path from the object to be read to the light receiving element are substantially parallel. Since the light source is not mounted on the moving unit, high-speed reading can be easily performed without catching the cable. A light source having the same length as the original is not required, and the apparatus housing is compact. In addition, since there is no influence of the reflected light of the mirror or the like, high image quality can be obtained even when reading a halftone original.

[0028]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of an image reading apparatus according to the present invention. In the figure, the same parts as those in FIGS. 7 to 10 are denoted by the same reference numerals, and detailed description of those parts will be omitted.

7, the image reading apparatus according to the present embodiment is different from the image reading apparatus of FIG. 7 in that an optical path from a light source to a reading surface and an optical path from the reading surface to a light receiving element are parallel. The point is that a fixed light source is arranged near the light receiving element. That is, the light source 1 is fixed to the device housing 15 so that the relative position with respect to the device housing 15 does not change. Therefore, since the light source is not mounted on the moving unit 4, the mass of the moving unit 4 does not increase, and the cable is not caught.

Referring to FIG. 2 showing the operation of the image reading apparatus, the moving units 4 and 5 move in the direction of arrow Y which is the sub-scanning direction, as in the conventional apparatus. However, in the present apparatus, the light source 1 is arranged near the one-dimensional CCD 3 and the optical path from the light source 1 to the reading surface M and the optical path from the reading surface M to the one-dimensional CCD 3 are parallel. You don't have to. In the same figure, the same parts as those in FIGS. 1 and 7 to 10 are indicated by the same reference numerals.

FIG. 3 shows another embodiment of the image reading apparatus according to the present invention. In the figure, the same parts as those in FIGS. 1 and 2 and FIGS. 7 to 10 are denoted by the same reference numerals, and detailed description of those parts will be omitted.

9, the image reading apparatus according to the present embodiment is different from the image reading apparatus of FIG. 9 in that the optical path from the light source to the reading surface and the optical path from the reading surface to the light receiving element are parallel. The point is that a fixed light source is arranged near the light receiving element. That is, the light source 1 is
, And the lens unit 11 is further
It is fixed to. Therefore, the light source 1 and the device housing 15
The relative position with respect to does not change.

Here, the irradiation light of the light source 1 is reflected by the mirror 14 and reaches the reading surface, and the reflected light of the reading surface is also reflected by the mirror 14 and reaches the lens unit 11. When the mirror 14 rotates, the reflection angle changes, and the reading position is changed in the order of A, B, and C.
It moves in the sub-scanning direction, that is, the direction of arrow Y.

Therefore, a light source having the same length as the original is not required.
Since an inexpensive light source can be used, the cost of the device can be reduced. In addition, since a small light source may be provided, the device housing becomes compact. Further, the optical path from the light source 1 to the reading surface and the one-dimensional C
Since the optical path to CD3 is parallel, it is easy to control the brightness of the reading surface, and it is possible to obtain high image quality even when reading a halftone document where the change in the brightness of the reading surface greatly affects the image quality. You can do it.

Referring to FIG. 4 showing the operation of the image reading apparatus, the lens unit 11 is moved and the mirror 1 is moved.
The point that 4 rotates about the axis J is the same as the conventional apparatus. However, in the present apparatus, the light source 1 is arranged near the one-dimensional CCD 3, and the optical path from the light source 1 to the reading surface M and the reading surface M
The difference is that the optical path from to the one-dimensional CCD 3 is parallel. As a result, even if the mirror 14 rotates, the light from the light source 1 can be constantly illuminated to the reading position, so that there is no need to provide a light source having the same length as the original. In this figure, the same parts as those in FIGS. 1 to 3 and FIGS. 7 to 10 are indicated by the same reference numerals.

Here, a more detailed configuration of the light source in the present invention will be described. FIG. 5 is a diagram showing a more detailed configuration near the light source in the image reading apparatus shown in FIGS. 1 and 2 described above. As shown in the drawing, light from the light source 1 is reflected by two mirrors 9 and further reflected by the mirrors 8 and then reaches a reading surface (not shown).
That is, the straight line indicated by the symbol A in the figure is the reading position.

The reflected light from the reading position A is reflected by the mirror 8 and further by the mirror 9 and enters the lens 2. This incident light is converted into a one-dimensional C
The light is condensed on the CD3 and converted into an electric signal.

Here, when it is desired to increase the amount of light from the light source, as shown in FIG. 6, a reflecting plate 16 is provided near the light source 1 so that the irradiation light from the light source has directivity. good. In the figure, by providing two reflecting plates 16 each having a curved surface for each of the two light sources, the light from the light source 1 can be condensed and the reading surface can be illuminated more strongly.

In this case, since the light amount of the light source 1 itself can be suppressed low, low power consumption can be realized. It goes without saying that the number of reflectors is not limited to the number shown in FIG. It is apparent that the same effect can be obtained even if directivity is provided by using a condenser lens or the like instead of the reflector.

Similarly, with respect to the light source of the image reading apparatus shown in FIGS. 3 and 4, if a reflection plate or the like is provided, the light amount of the light source itself can be suppressed low, so that low power consumption can be realized.

The present invention can further take the following aspects in connection with the description of the claims.

(4) The light collecting means is a reflector provided near the light source.
The image reading device according to any one of the above.

(5) It further comprises a mirror for reflecting light from the light source and irradiating the object to be read, and mirror driving means for changing a position of the mirror to irradiate light to the object to be read. The image reading device according to any one of claims 1 to 4.

(6) The image reading apparatus according to any one of claims 1 to 5, wherein the mirror driving means moves the mirror in a predetermined direction with respect to the object to be read.

(7) The image reading apparatus according to any one of claims 1 to 5, wherein the mirror driving means changes a reflection angle of the light from the light source on the mirror.

[0047]

As described above, according to the present invention, the fixed light source and the light receiving element are arranged so that the optical path from the light source to the object to be read and the optical path from the object to be read to the light receiving element are substantially parallel. Since the light source is not mounted on the moving unit, there is an effect that the cable is not caught and high-speed reading is facilitated. Further, there is no need for a light source having the same length as that of the document, and there is an effect that the apparatus housing becomes compact. In addition, since there is no influence of the reflected light of the mirror or the like, there is an effect that high image quality can be obtained even when reading a halftone original.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an image reading device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of the image reading apparatus of FIG. 1;

FIG. 3 is a diagram illustrating a configuration of an image reading device according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating an operation of the image reading apparatus of FIG. 2;

FIG. 5 is a diagram illustrating a more detailed configuration near a light source of the image reading apparatus of FIG. 1;

FIG. 6 is a diagram illustrating another configuration example near the light source of the image reading apparatus in FIG. 1;

FIG. 7 is a diagram illustrating a configuration of a conventional image reading apparatus.

FIG. 8 is a diagram illustrating an operation of the image reading apparatus of FIG. 7;

FIG. 9 is a diagram illustrating a configuration of another conventional image reading apparatus.

FIG. 10 is a diagram illustrating the operation of the image reading apparatus of FIG. 9;

[Explanation of symbols]

 1, 26, 32 Light source 2 Lens 3 One-dimensional CCD 4, 5 Moving unit 6 Driving pulley 7 Follower pulley 8, 9, 14 Mirror 10 Wire 11 Lens unit 12 Cam 13 Link 14 Mirror 15 Housing 16 Reflector

Claims (3)

[Claims] 1. An image reading apparatus comprising: a fixed light source; and a light receiving element configured to irradiate light from the light source to a reading target and receive reflected light from the reading target. An image reading apparatus, wherein the light source and the light receiving element are arranged such that an optical path of the light source and an optical path from the object to be read to the light receiving element are substantially parallel to each other. 2. The image reading apparatus according to claim 1, wherein the light receiving element is disposed near the light source. 3. The image reading apparatus according to claim 1, further comprising a light condensing unit that condenses light from the light source on the object to be read.