JP2001274950A - Picture reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dust from staying on an original platen where an original is carried by an automatic original feeding device and to prevent the occurrence of a picture defects such as a black line and a void. SOLUTION: A picture reader is provided with the automatic original feeding device transporting the original, the original platen 20 which is arranged in a state where it is confronted with the original carried by the automatic original feeding device and has an inclination face 20A where the up stream side of an original carrying direction F is arranged in a high order and optical scanning systems (5, 6A and 6B) reading the picture of the original carried on the original stand 20.

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 used for a copying machine, a scanner and the like.

[0002]

2. Description of the Related Art Digital copying machines, facsimile machines, and scanners use an image reading apparatus which forms reflected light from a document on an image sensor and reads the image.

FIG. 10 is a schematic diagram showing an example of a conventional image reading apparatus. The illustrated image reading apparatus 1 includes an apparatus frame 2, a document table 3 such as a platen glass, a document pressing member 4 such as a platen cover, an illumination lamp 5, first to third mirrors 6A to 6C, an image forming lens 7, An image sensor 8 including a CCD line sensor or the like is provided. An automatic document feeder 9 is mounted above the image reading device 1.

[0004] The apparatus frame 2 is made of a rigid body such as metal and has a substantially box-shaped structure with an open upper part. The document table 3 is attached to the upper part of the apparatus frame 2 so as to cover the opening. Document holding member 4
Is attached to the upper part of the device frame 2 so as to be freely opened and closed,
The original placed on the original platen 3 is pressed from above.
The illumination lamp 5 and the first mirror 6A are mounted on a full rate carriage 10, and the second mirror 6B and the third mirror 6C are mounted on a half rate carriage 11.

The lens 7 optically reduces the optical images reflected by the first, second, and third mirrors 6A, 6B, and 6C to form an image on an image sensor 8. The image sensor 8 photoelectrically converts an optical image formed by the lens 7, and an image signal obtained by the photoelectric conversion is sent to the signal processing board 13 via the drive board 12.

Here, the image of the document placed on the document table 3 is composed of the illumination lamp 5 and the first mirror 6A mounted on the full rate carriage 10, and the second and third mirrors mounted on the half rate carriage 11. The image is read by an optical scanning system including 6B, 6C, lens 7, and image sensor 8. That is, when reading the image of the document set on the document table 3, the full rate carriage 10 and the half rate carriage 11 move in the SCAN direction (arrow direction) at a ratio of 2: 1. At this time, the light of the illumination lamp 5 irradiates the reading surface of the document, and the reflected light (optical image) from the document is reflected by the first, second, and third mirrors 6A, 6A.
The light is sequentially reflected by 6B and 6C and guided to the lens 7. Then, the image is reduced by the lens 7 and formed on the light receiving surface of the image sensor 8. Thereby, the image of the document is read by the optical scanning system.

The automatic document feeder 9 includes a document tray 14,
It is provided with a pair of registration rollers 15, a feed roller 16, a transport guide 17, a discharge roller 18, and the like. In the automatic document feeder 9, a document 19 placed on a document tray 14 is sent out by a pair of registration rollers 15 and then conveyed at a constant speed by a feed roller 16. At this time, the document 19 is guided by the transport guide 17 so as to pass over the second document table 20, where the image of the document 19 is read by the optical scanning system.
The document 19 that has passed over the second document table 20 is discharged onto the document pressing member 4 (or a document discharge tray provided on the document pressing member 4) by the discharge roller 18. Hereinafter, in order to avoid confusion with the second platen 20,
The aforementioned platen 3 is referred to as a “first platen”.

In the image reading apparatus shown in FIG. 10, the surface to be read of the document 19 (the surface on which the image to be read is recorded) is located on the second document table 20 at the image reading position. The original is set downward on the original tray 14 so as to face the original, and the original is conveyed linearly while being downward and discharged onto the original pressing member 4. However, in such a linear transport system, it is necessary to secure a space for placing the original before reading and a space for discharging the original after reading in a straight line.
The occupied space of the automatic document feeder 9 becomes large.

For this reason, in recent years, a space-saving type image reading apparatus as shown in FIG. 11 is frequently used. This image reading apparatus 1 is the same as the apparatus shown in FIG. 10 except for the automatic document feeder 9.

The automatic document feeder 9 mounted on the image reading apparatus 1 shown in FIG. 11 includes a document tray 21, a pair of registration rollers 22, a transport roller 23, a feed roller 24,
It is provided with a transport guide 25, a discharge roller 26, and the like. In the automatic document feeder 9, after a document 19 placed on a document tray 21 is sent out by a pair of registration rollers 22, a conveying roller 23 and a feed roller 2
4 conveys at a constant speed. At that time, manuscript 19
Is transported by a transport roller 23 and a feed roller 24 so as to form a substantially U-shape, and is guided by a transport guide 25 so as to pass over the second document table 20 as shown in FIG. Original 1 by optical scanning system
Nine images are read. The document 19 that has passed over the second document table 20 is discharged onto the document pressing member 4 by the discharge roller 26.

In the image reading apparatus 1, a document 19 set upward on a document tray 21 is conveyed in a substantially U-shape so that the surface to be read of the document 19 faces downward on a second document table 20. , And the original 19 is discharged onto the original pressing member 4 with the original 19 facing downward. In such an apparatus configuration, the space for mounting the original before reading and the space for discharging the original after reading are vertically arranged, thereby realizing space saving of the apparatus.

[0012]

However, FIG.
In the image reading apparatus 1 shown in FIG. That is, in the image reading apparatus 1, the document 19 set upward on the document tray 21 is transported in a substantially U-shape and passed over the second document table 20.
The surface to be read becomes the second due to the bending deformation (curvature deformation) of 9 itself.
Of the document table 20 is pressed. for that reason,
For example, if dust such as eraser dust or paper dust adheres to the read surface of the document 19, the dust is conveyed in a substantially U-shape as described above at the moment the read surface of the document 19 faces downward. Are dropped and scattered on the second platen 20, and further pressed together with the document 19, so that dust adheres to the second platen 20. When dust adhering to the second document table 20 stagnates at the image reading position by the optical scanning system, light from the illumination lamp 5 is blocked by the dust. Defects such as streaks and white spots will occur.

Although such a problem also occurs in the image reading apparatus 1 shown in FIG. 10 described above, in particular, in the space-saving type image reading apparatus 1 (FIG. 11), the document 19 is transported in a substantially U-shaped curve. Because of this, trash is easy to fall and the frequency of occurrence is high.

As a measure against such a problem, the present applicant disclosed in Japanese Patent Application Laid-Open No. 9-307695 that when the original 19 is fed onto the second original platen 20, the original 19 is read at the image reading position by the optical scanning system. Second platen 20
There is proposed a technique of providing a contact prevention member that does not make contact. According to the technique described in this publication, dust adhering to the surface to be read of the original 19 can be dropped on the contact prevention member, and the original 19 is pressed against the second It is possible to prevent dust from adhering to the second document table 20.

However, according to the technology described in the above publication, as the number of read originals increases, dust accumulated on the contact prevention member falls on the second original platen 20 and further conveys the originals. As a result, dust on the second document table 20 gradually moves under the influence of static electricity and the like and stagnates at the image reading position, thereby causing image defects such as black streaks and white spots in the read image as described above. There was fear.

[0016]

In an image reading apparatus according to the present invention, a transporting means for transporting a document, and a document being transported by the transporting means and arranged in a state facing the document transported by the transporting means. A transparent member having an inclined surface with the upstream side or the downstream side arranged at a high position in the direction and a reading unit for reading an image of a document conveyed on the transparent member are adopted.

In the image reading apparatus having the above structure, even if dust adhered to the surface to be read of the document falls on the transparent member during the transport of the document by the transport means, the dropped dust is collected in one place. Without stagnation, the transparent member slides down smoothly along the inclined surface.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the present embodiment, the same components as those described in the related art will be denoted by the same reference numerals and described.

FIG. 1 is a schematic view showing an image reading apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic view showing a main part thereof. The illustrated image reading apparatus 1 includes an apparatus frame 2, a first document table 3 such as a platen glass, a document pressing member 4 such as a platen cover, an illumination lamp 5, and first to third mirrors 6.
A to 6C, an imaging lens 7, an image sensor 8 including a CCD line sensor, and the like. An automatic document feeder 9 is mounted above the image reading device 1.

The device frame 2 is made of a rigid body such as metal and has a substantially box-like structure with an open upper portion. The first document table 3 is attached to the upper portion of the apparatus frame 2 so as to close the opening. The document pressing member 4 is attached to the upper part of the apparatus frame 2 so as to be openable and closable, and presses a document placed on the first document table 3 from above. The illumination lamp 5 and the first mirror 6A are mounted on a full rate carriage 10, and the second mirror 6B and the third mirror 6C are mounted on a half rate carriage 11.

The lens 7 optically reduces the optical images reflected by the first, second, and third mirrors 6A, 6B, and 6C to form an image on the image sensor 8. The image sensor 8 photoelectrically converts the optical image formed by the lens 7, and is constituted by, for example, an image sensor (such as a CCD line sensor) having a large number of read pixels. The image signal obtained by the image sensor 8 is sent to the signal processing board 13 via the drive board 12.

Here, the image of the original placed on the first platen 3 is composed of the illumination lamp 5 and the first mirror 6A mounted on the full-rate carriage 10 and the second and second mirrors 6A mounted on the half-rate carriage 11. The image is read by an optical scanning system including the third mirrors 6B and 6C, the lens 7, and the image sensor 8. That is, when reading the image of the document set on the first document table 3, the full-rate carriage 10 and the half-rate carriage 11 move in the SCAN direction (arrow direction) at a ratio of 2: 1. At this time, the light of the illumination lamp 5 irradiates the reading surface of the document, and the reflected light (optical image) from the document is reflected by the first, second, and third mirrors 6A, 6B, and 6C in order. It is guided to the lens 7. Then, the image is reduced by the lens 7 and formed on the light receiving surface of the image sensor 8. Thereby, the image of the document is read by the optical scanning system.

The automatic document feeder 9 includes a document tray 21,
It includes a pair of registration rollers 22, a transport roller 23, a feed roller 24, a transport guide 25, a discharge roller 26, and the like, and is configured integrally with the document pressing member 4. In the automatic document feeder 9, the original 1 placed on the original tray 21
After 9 is sent out by the pair of registration rollers 22,
The sheet is conveyed at a constant speed by the conveying roller 23 and the feed roller 24. At this time, the original 19 is transported by the transport roller 23 and the feed roller 24 so as to form a substantially U-shape, and is transported by the transport guide 25 to the second platen 2.
The document is guided so as to pass over the zero, and the image of the original 19 is read there by the optical scanning system. The document 19 that has passed over the second document table 20 is discharged by the discharge roller 26 onto the document pressing member 4 (or a document discharge tray provided on the document pressing member 4).

The second document table 20 is formed of, for example, a transparent glass plate having a long plate-like structure, and corresponds to a transparent member in the present invention. This second
The document table 20 is provided with the transport roller 23 and the feed roller 24.
And a document 19 (read surface) conveyed by a conveyance unit including a conveyance guide 25. In the present embodiment, glass is used as the material of the second document table 20, but other than this, for example, a transparent resin may be used.

On the other hand, the full-rate carriage 10 of the optical scanning system has a home position below the second document table 20. The optical scanning system moves the full-rate carriage 10 from the home position in the sub-scanning direction (SC) indicated by an arrow in FIG.
(The AN direction) to read the image of the original placed on the first original platen 3, stop the full-rate carriage 10 at the home position, and transfer the image of the original 19 conveyed onto the second original platen 20. Is read.

Hereinafter, an operation mode in which an image of a document placed on the first document table 3 is read by the optical scanning system is referred to as a “first reading mode”, and the automatic document feeder 9 uses the second document table. An operation mode in which an image of the document conveyed onto the document 20 is read by the optical scanning system is referred to as a “second reading mode”.

Here, in the present embodiment, while the first document table 3 is arranged in a horizontal state, the second document table 20 is tilted from the horizontal state by a predetermined angle, so that the second document table 20 is inclined. The document table 20 is in the document transport direction F by the transport means.
It has an inclined surface 20A in which the upstream side (see FIG. 2) (left side in the figure) is higher than the downstream side (right side in the figure). The inclined surface 20A is disposed so as to be close to (in some cases, in contact with) the surface to be read of the original 19 conveyed onto the second original platen 20, for example, the first original in a horizontal state. With respect to the upper surface of the table 3 (the document
They are arranged with a tilt angle of approximately 30 °. In addition,
Although the positional relationship between the illumination lamp 5 and the first mirror 6A is reversed in FIGS. 1 and 2, there is no functional difference between them.

In the image reading apparatus 1 provided with the second document table 20 having such an inclined surface 20A, a pair of registration rollers 22, a transport roller 23 and a feed roller 24 are provided.
When the original 19 is conveyed onto the second platen 20, even if dust adhered to the surface to be read of the original 19 falls on the second platen 20, the dust is It will slide down along 20A. This allows
Since dust does not stay at the image reading position by the optical scanning system on the second document table 20, it is possible to effectively prevent defects such as black lines and white spots from occurring in the read image.

In the above-described embodiment, the inclined surface 20A is formed by inclining the second document table 20 as a whole. Alternatively, for example, the thickness of the second document table 20 may be changed. By changing the dimensions, the inclined surface 20A similar to the above can be used without tilting the second document table 20 as a whole.
Can be formed.

Further, in the above-described embodiment, as an example of the arrangement of the inclined surface 20A of the second document table 20, an example in which the upstream side in the document conveyance direction F is disposed higher than the downstream side has been described. Conversely, even when the downstream side in the document conveying direction F is arranged higher than the upstream side, the desired effect can be obtained by the sliding of dust along the inclined surface 20A.

However, when the upstream side in the document conveyance direction F is arranged higher than the downstream side as described above, the following specific effects can be obtained. That is, since the conveying direction F of the document by the conveying means and the moving direction (sliding down direction) of the dust on the inclined surface 20A are aligned, the movement of the dust on the inclined surface 20A is promoted by an electrostatic action or the like at the time of conveying the document. Second
Dust can be quickly removed from the document table 20 of the printer. As a result, it is possible to more reliably prevent image quality defects such as black lines and white spots caused by dust remaining at the image reading position by the optical scanning system. Further, since the inclined surface 20A of the second platen 20 and the surface to be read of the document passing on the second platen 20 are arranged in a substantially parallel manner, the first platen 20 ( The document is not pressed against the inclined surface 20A). Therefore, it is possible to effectively prevent dust from adhering to the second document table 20.

When the inclined surface 20A is formed by inclining the second document table 20 as in the above-described embodiment, the influence of the refractive index of the second document table 20 on the surface to be read of the document is obtained. The angle of the reading optical axis of the optical scanning system is not a right angle. Then, in the optical scanning system, the read surface of the document is read in an oblique direction, so that the document conveyed onto the second document table 20 is scanned by the image sensor 8.
The projection size per pixel changes in the document transport direction F. As a result, even when reading the image of the same original,
Reading is performed by setting the original on the original platen 3 and reading (first reading mode), and reading the original by transporting it onto the second original platen 20 by the automatic original feeder 9 (second reading mode). A difference occurs in the image quality (resolution) of the image. Specifically, when the document is conveyed onto the second document table 20 and read, the image is read with lower image quality.

In the image reading apparatus 1 using the reduced optical scanning system as described above, when the optical distance (optical path length) from the document surface to the light receiving surface of the image sensor fluctuates, the main scanning is performed in conjunction therewith. The imaging magnification in the direction (the direction orthogonal to the sub-scanning direction) also varies. On the other hand, when the second platen 20 having the inclined surface 20A is employed as in the above-described embodiment, the original surface is also arranged obliquely along the inclined surface 20A. The optical distance is likely to fluctuate due to the mounting position accuracy of the second document table 20 and the like.

As a result, even when the image of the same original is read, there are cases where the original is set on the first original plate 3 and read, and when the automatic original feeder 9 conveys the original onto the second original plate 20 and reads. In addition, errors tend to occur in the reading magnification in the main scanning direction.

Therefore, in this embodiment, the above-mentioned difficulty is solved by the following application example.

FIG. 3 is a diagram showing a configuration of a first application example of the present embodiment. As can be seen from FIG. 3, the second platen 20
Is continuously smaller (thinner) from the higher side (left side in the figure) to the lower side (right side in the figure) of the inclined surface 20A.
Accordingly, the lower surface (the surface opposite to the inclined surface 20A) 20B of the second document table 20 is arranged in an inclined state.

More specifically, as shown in FIG. 4, for example, when the inclined surface 20A of the second document table 20 is arranged with an inclination of θ1 = 30 ° with respect to the horizontal reference plane,
The refractive index of the second platen 20 is set to the refractive index n of general glass.
1 = 1.518, the lower surface 20B of the second document table 20 is set in the same direction as the inclined surface 20A with respect to the horizontal reference plane, and θ2 = 67.
Place at an angle of 485 °. As a result, light in the vertical direction orthogonal to the horizontal reference plane is transmitted to the lower surface 20 </ b> B of the second platen 20.
At an angle of θ3 = 67.485 ° with a perpendicular line S perpendicular to the axis, and inside the second document table 20, a formula n2 × sin θ3 = n1 × sin θ where the refractive index of air is n2 = 1.
4, θ4 = sin ⁻¹ {sin (67.485 °) /
1.518} = Slope 2 at an angle of 37.485 °
It will advance to 0A. The light traveling on the inclined surface 20A in this manner makes a right angle with the inclined surface 20A, whereby the reading optical axis of the optical scanning system with respect to the surface to be read of the document can be corrected to a right angle.

As a result, when reading the image of the same document, when setting and reading on the first document table 3 (first reading mode), the automatic document feeder 9 places the image on the second document table 20. In the case of transporting and reading (second reading mode), the image quality (resolution) of the read image can be made uniform with high quality.

FIG. 5 is a block diagram of an image reading apparatus showing a second application example of the present embodiment. In FIG. 5, the CPU
(Central processing unit) 31 controls the processing operation of the entire apparatus according to a preset control program. The CPU 31 includes various driving circuits (not shown) for controlling the movement operation of the carriages 10 and 11 and the lighting operation of the illumination lamp 5 in the optical scanning system, and the rotation operation of each roller of the automatic document feeder 9. , A magnification adjusting circuit 32.

The magnification adjusting circuit 32 includes an image sensor 8 such as a CCD, an amplifier (AMP) 33, an A / D (analog / digital) converter 34, and a shading correction circuit 3.
5 is to adjust the reading magnification of the image data taken in via the line 5. The reading magnification adjusted by the magnification adjusting circuit 32 is a reading magnification in the main scanning direction scanned by the image sensor 8.

A correction RAM (RAM is a random access memory) 36 stores data for setting a magnification. In the correction RAM 36, a magnification setting value α corresponding to the first reading mode and a magnification setting value β corresponding to the second reading mode are stored as magnification setting data. Further, the data for setting the magnification (magnification setting values α, β) can be arbitrarily set and changed via the operation panel 37.

By adopting such an apparatus configuration, when the reading magnification when operating in the first reading mode is different from the reading magnification when operating in the second reading mode, each reading is performed. By changing the magnification setting values α and β stored in the correction RAM 36 using the operation panel 37 according to the mode, it is possible to eliminate an error in the reading magnification due to the difference in the reading mode.

By the way, in the second application example, the first
Although the reading magnification in the second reading mode and the reading magnification in the second reading mode can be individually set, the reading magnification in either one of the reading modes is required to make the reading magnifications in both reading modes uniform. Any configuration may be used as long as it is possible to set However, in the first reading mode, an original is set on the first original platen 3 arranged in a horizontal state, and each carriage 1 is set in parallel with the first original platen 3.
Change in reading magnification (out of order) because 0 and 11 move
Is hard to occur, and there is almost no need for readjustment once the magnification is adjusted. Therefore, it is very effective to provide a unit for adjusting the reading magnification in the second reading mode.

Further, as shown in FIG. 6, the marks M1 and M2 are provided outside the maximum document width W1 readable by the image reading apparatus and inside the maximum image width W2 readable by the image sensor 8, respectively. CPU 3 described later
It is also possible to automatically adjust the reading magnification in the main scanning direction by the processing operation of (1). In FIG. 6, the marks M1 and M2 are provided on the transport chute 25 disposed above the second document table 20, but similar marks are formed on the second document table 20 under the above-described arrangement conditions. May be provided.

FIG. 7 is a flowchart showing a processing procedure executed by the CPU 31 when adjusting the magnification. As illustrated, the CPU 31 first drives the carriage motor to move the full-rate carriage 10 and the half-rate carriage 11 in the sub-scanning direction, while each of the carriages 10 and 11 corresponds to the position corresponding to the second reading mode ( For example, it is determined whether or not the carriage has reached the home position based on a detection signal from the position sensor (steps S1 and S2). Then, when each of the carriages 10 and 11 reaches a position corresponding to the second reading mode, the movement of the carriage is stopped (step S3).

Subsequently, the CPU 31 turns on the illumination lamp 5 and displays the images of the marks M 1 and M 2 on the image sensor 8.
(Steps S4 and S5). After that, CPU3
1 calculates a distance X (distance between two points) between the marks M1 and M2 from the image read earlier, and further calculates a magnification error ΔX using the calculated distance X (step S6).
S7). In calculating the magnification error ΔX, for example, the distance (actual distance) between the marks M1 and M2 when forming the mark
Is L, it can be obtained by ΔX = X / L × 100. As an example, when X = 305 mm and L = 300 mm, ΔX = 101.67% is calculated.

After calculating the magnification error ΔX, the CPU 31 subsequently writes the magnification error ΔX into the correction RAM 36 as magnification setting data (in this case, the magnification setting value α) (step S8). Thereafter, when operating in the second reading mode, the reading magnification in the main scanning direction is corrected (adjusted) based on the magnification setting data written in step S8.

By the way, the magnification error ΔX is 101.67%
As a specific magnification adjustment method when is calculated, among the pixel data obtained by the image sensor 8,
The value obtained by multiplying the data of the first pixel by 1 and the data of the second pixel by 0.
A value obtained by dividing the sum by 1.0167 is used as correction data for the first pixel,
By performing the same operation on the data of the second and subsequent pixels, a read image (image data) matched to the actual magnification can be output.

As described above, the two marks M1 and M2 are provided, the images thereof are read, the distance between the marks M1 and M2 is calculated based on the read result, and the magnification setting magnification is determined based on the calculated result. Obtaining the data makes it possible to automatically adjust the reading magnification in the main scanning direction.

In the second application example, the case where the reading magnification in the main scanning direction is adjusted by an electric process has been described as an example. In addition, the reading magnification is adjusted mechanically. It is also possible. Hereinafter, two specific cases will be described.

One uses an adjustment mechanism for adjusting the position of the second document table 20 in the height direction (hereinafter, referred to as a first adjustment mechanism), and the other uses the adjustment mechanism for the second document table 20. An adjustment mechanism (hereinafter, referred to as a second adjustment mechanism) for adjusting the position in a direction along the document transport direction is used.

FIGS. 8A and 8B show a first adjustment mechanism relating to the magnification adjustment. FIG. 8A is a perspective view of the first adjustment mechanism, and FIG. 8A and 8B, a receiving portion 40 is provided at an upper portion of the device frame 2. This receiving part 4
0 is the second platen 20 placed on the apparatus frame 2
It is for supporting.

The receiving portion 40 is formed substantially horizontally with a part of the device frame 2 cut out and the cut part bent outward. Here, the receiving portion 40 is formed integrally with the device frame 2, but may be formed as a separate component. The receiving portion 40 is provided with two male screws 41A and 41B and one screw hole 42.
Each of the male screws 41A and 41B is erected substantially vertically on the receiving portion 40 in a fixed state (rotationally locked state). Each male screw 41A, 41B has a nut 4 for height adjustment.
3A and 43B are rotatably mounted.

As the second document table 20, a transparent glass plate having a long flat plate structure is used. The second document table 20 is supported with its peripheral edge on the upper surface side attached to a holder frame 44. Holder frame 4
4 is obtained, for example, by integral molding of a resin or bending of a metal plate. This holder frame 44
A guide portion 44A fixed to the second document table 20 with a double-sided tape or the like, a side wall portion 44B hanging at a substantially right angle from a side end of the guide portion 44A, and a substantially right angle (horizontal direction) from a lower end of the side wall portion 44B. And an integral structure having a wing portion 44 </ b> C extending to the outside. The side wall 44B and the wing 44
C is provided on both sides of the holder frame 44 in the long side direction, and correspondingly, the receiving portions 40 of the device frame 2 are also provided on both sides. However, on one side (not shown), only one set of adjusting parts combining a male screw and a nut is provided.

The side wall 44B of the holder frame 44
The upper side has an inclination with respect to the lower side, and the second platen 20 is supported by the inclination as a whole. The wing portion 44C of the holder frame 44 is provided with two fitting holes 45A and 45B into which the male screws 41A and 41B are fitted.

The fixing bracket 46 is for fixing the second document table 20 via the holder frame 44, and is formed in a stepped plate shape from a spring steel material such as stainless steel. One of the fixing brackets 46 is formed as a pressing portion 46A and the other as a fixing portion 46B with the stepped portion as a boundary. The holding portion 46A is provided with two fitting holes 47A and 47B into which the male screws 41A and 41B are fitted, and the fixing portion 46B is provided with one fixing hole 48.

In the first adjusting mechanism having the above configuration, when the second document table 20 is arranged on the apparatus frame 2, first, the wing 44C of the holder frame 44
The two fitting holes 45A and 45B provided in the first and second fittings are fitted to the corresponding male screws 41A and 41B, respectively. Thus, the wing 44C of the holder frame 44 comes into contact with the upper surfaces of the nuts 43A and 43B mounted on the male screws 41A and 41B.

At this time, the second document table 20 is placed on the apparatus frame 2 in a state of being attached to the holder frame 44. On the apparatus frame 2, the transport chute 49 and the cushion member (sponge or the like) 50 are interposed between the second document table 20 and the first document table 3. The transport chute 49 guides the document that has passed over the second document table 20 in a predetermined direction and discharges the document. The cushion member 50 is for preventing a gap from being generated at a portion where the second document table 20 and the transport chute 49 abut against each other, and is attached to the transport chute 49 using a double-sided tape or the like.

Next, the two fitting holes 47A and 47B provided in the holding portion 46A of the fixing bracket 46 are fitted into the corresponding male screws 41A and 41B, respectively.
Thus, the holding portion 46A of the fixing bracket 46 is disposed on the wing 44C of the holder frame 44, and at the same time, the fixing portion 46B of the fixing bracket 46 is disposed on the receiving portion 40.

Subsequently, the fixing screw 51 is screwed into the screw hole 42 of the receiving portion 40 through the fixing hole 48 of the fixing bracket 46. As a result, the wings 44C of the holder frame 44 are fixed to the pressing portions 46A and 2
Between the two nuts 43A and 43B,
It is pressed and fixed by the elastic force (spring pressure) of the fixing bracket 46.

In the first adjusting mechanism having such a configuration, when the two nuts 43A and 43B mounted on the male screws 41A and 41B on the receiving portion 40 are respectively rotated once, each of the nuts 43A and 43B is rotated. Is moved in the axial direction (vertical direction) of the male screws 41A and 41B by the screw pitch. As a result, the heights of the nuts 41A and 41B that receive the holder frame 44 change, and in conjunction with this, the height position of the second document table 20 also changes.

The moving amounts and moving directions of the nuts 43A and 43B correspond to the amounts and directions of rotation of the nuts 43A and 43B, respectively.
Therefore, by adjusting the amount and direction of rotation of each of the nuts 43A and 43B, the position of the second document table 20 in the height direction can be adjusted arbitrarily.

In the image reading apparatus having the first adjusting mechanism capable of adjusting the position of the second document table 20 in the height direction, the first reading mechanism mounted on the full-rate carriage 10
It is possible to adjust the distance between the mirror 6A and the surface to be read of the document sent on the second document table 20, and thus the above-described optical distance. Thereby, the reading magnification in the main scanning direction is adjusted (fine adjustment) in the second reading mode.
Therefore, the reading magnification in the first reading mode and the reading magnification in the second reading mode can be mechanically matched.

FIG. 9 is a perspective view showing a second adjustment mechanism relating to magnification adjustment. In FIG. 9, a receiving portion 52 is provided on an upper portion of the device frame 2. This receiving portion 52
A state in which a part of the apparatus frame 2 is incised and the incised part is bent outward as in the case of the first adjustment mechanism, for supporting a second document table 20 disposed on the apparatus frame 2. And are formed substantially horizontally. Receiving part 52
Are provided with two screw holes 53A and 53B.

The support bracket 54 is placed on the receiving portion 52 and fixed by fixing screws 55A and 55B, and is obtained by, for example, integrally molding a resin or bending a metal plate. The support bracket 54 includes an inclined piece 54A inclined at a predetermined angle, a side piece 54B hanging substantially at a right angle from an end side of the inclined piece 54A, and a substantially right angle (horizontal direction) extending from a lower side of the side piece 54B. 54C of fixing pieces that have come out,
It has an integral structure including a fixed piece 54C and a bent piece 54D which is bent at a substantially right angle in the same direction from the side of the side piece 54B. Of these, two screw holes 55A and 55B are provided on the inclined piece 54A, two fitting holes 56A and 56B are provided on the fixed piece 54C, and one fitting hole 5 is provided on the bent piece 54D.
7 are provided.

The support frame 58 is obtained, for example, by integral molding of resin or bending of a metal plate, and is fixed to the second document table 20 with a double-sided tape or the like. The support frame 58 is provided with two long holes 59A and 59B located outside the position where the second document table 20 is attached. These long holes 59A and 59B have a long hole shape along the short side direction of the second document table (transparent glass having a long flat plate structure) 20 adhered to the support frame 58. Further, the support frame 58 has an adjusting piece 58A.
Are integrally formed. The adjustment piece 58A is formed so as to protrude outward from both sides of the support frame 58. Further, one adjusting screw hole 60 is provided in the adjusting piece 58A.

In arranging the second document table 20 on the apparatus frame 2 in the second adjusting mechanism having the above configuration, first, the support bracket 54 is placed on the receiving portion 52. At this time, the fixing piece 54C of the support bracket 54
Comes into contact with the receiving portion 52. Next, the two fitting holes 5 provided in the fixing piece 54C of the support bracket 54 are formed.
The fixing screws 61A and 61B are respectively passed through 6A and 56B and screwed into the screw holes 53A and 53B of the receiving portion 52. As a result, the support bracket 54 is fixed on the receiving portion 52.

Subsequently, the support frame 58 to which the second document table 20 has been attached is placed on the inclined piece 54A of the support bracket 54, and is fixed to the two elongated holes 59A and 59B provided in the support frame 58, respectively. Screw 62A, 62
B is screwed into each screw hole 55A, 55B of the inclined piece 54A. Thus, the support frame 58 is fixed to the support bracket 54.

In this state, the support bracket 54
Bent piece 54D and support frame 58 adjustment piece 58
A oppose each other at a predetermined distance, and the bent piece 54
The fitting hole 57 provided in D and the adjusting screw hole 60 provided in the adjusting piece 58A are arranged substantially coaxially with each other.
Also, on the apparatus frame 2, a state in which the transport chute 49 and the cushion member (such as a sponge) 50 are interposed between the second document table 20 and the first document table 3 as in the case of the first adjustment mechanism. Become. Thereafter, the adjusting screw 63 is passed through the fitting hole 57 and screwed into the adjusting screw hole 60.

Here, it is assumed that the support frame 58 is fixed to the support bracket 54 after the support bracket 54 is fixed to the receiving portion 52. On the contrary, after the support frame 58 is fixed to the support bracket 54, The support bracket 54 may be fixed to the receiving portion 52.

In the second adjusting mechanism having such a configuration, by loosening the tightening of the two fixing screws 62A and 62B, the two fixing screws 62A and 62B are loosened.
The support frame 58 is slid along the inclined piece 54A by the dimensional play between the 62B and the corresponding two long holes 59A and 59B, and the second frame is integrally formed with the support frame 58.
Can be moved in the f1 and f2 directions in the figure. At this time, the direction in which the second platen 20 moves is
This is the direction along the conveyance direction of the document conveyed by the automatic document feeder 9.

A state in which the two fixing screws 62A and 62B are appropriately loosened (lightly tightened).
By rotating the adjustment screw 63 in a predetermined direction, the adjustment piece 58A of the support frame 58 is drawn toward the bent piece 54D side of the support bracket 54, and both (5)
8A, 54C) is reduced. At this time, the support frame 58 slides in the direction f1 in the figure along the inclined piece 54A of the support bracket 54, and the second frame 20 is integrally moved therewith.
Also moves in the f1 direction. In addition, the amount of movement of the second document table 20 at this time corresponds to the amount of rotation of the adjusting screw 63.

From this, the second document table 20 is moved to f
By rotating the adjusting screw 63 as described above from the state of being moved most in the two directions, the second document table 2 is moved in the f1 and f2 directions in the drawing, that is, in the direction along the document transport direction.
The position of 0 can be adjusted (finely adjusted).

As described above, in the image reading apparatus having the second adjusting mechanism capable of adjusting the position of the second document table 20 in the direction along the document conveying direction, for example, as in the first application example, the second reading mechanism is used. When the thickness of the platen 20 is changed and its cross-sectional shape is substantially wedge-shaped, the second platen 20 is set to y1,
By moving in the y2 direction, the thickness of the second document table 20 at the image reading position changes. As a result, due to the difference between the refractive index of the glass constituting the second platen 20 and the refractive index of air, the inclined surface 20A of the second platen 20
Without changing the absolute dimensions from the
The optical dimensions in the meantime can be changed. As a result, the reading magnification in the main scanning direction can be adjusted (finely adjusted) in the second reading mode in the same manner as in the first adjusting mechanism, so that the reading magnification in the first reading mode and the second reading mode can be adjusted. The reading magnification in the reading mode can be mechanically adjusted.

In the second adjusting mechanism, the direction for adjusting the position of the second document table 20 is set to the y1 and y2 directions. However, the second direction may be set to the second direction in the sub-scanning direction along the document conveying direction. Even if the position of the document table 20 is adjusted, the reading magnification in the main scanning direction can be adjusted. Also,
The receiving portion 52 and the support holder 54 can be formed as an integral structure.

[0076]

As described above, according to the image reading apparatus of the present invention, dust is retained at the image reading position by the reading means by providing the inclined surface on the transparent member on which the document is conveyed by the conveying means. As a result, defects such as black lines and white spots can be effectively prevented from occurring in the read image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a main part of the image reading apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a first application example of the present invention.

FIG. 4 is a diagram illustrating details of a first application example.

FIG. 5 is a block diagram showing a second application example of the present invention.

FIG. 6 is a diagram showing mark formation positions for automatic magnification adjustment.

FIG. 7 is a flowchart illustrating a processing procedure for automatic magnification adjustment.

FIG. 8 is a diagram illustrating a first adjustment mechanism related to magnification adjustment.

FIG. 9 is a perspective view showing a second adjustment mechanism related to magnification adjustment.

FIG. 10 is a schematic diagram illustrating an example of a conventional image reading apparatus.

FIG. 11 is a schematic view showing another example of a conventional image reading apparatus.

FIG. 12 is a partially enlarged view of a conventional image reading apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image reading device, 3 ... 1st original platen, 4 ... Original document holding member, 5 ... Illumination lamp, 6A, 6B, 6C ... Mirror, 7
... Lens, 8 ... Image sensor, 9 ... Automatic document feeder, 10 ... Full rate carriage, 11 ... Half rate carriage, 20 ... Second document table, 20A ... Slope, F
… Document transport direction

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06T 1/00 420 G06T 1/00 420J 5C062 H04N 1/04 H04N 1/12 Z 5C072 F-term (Reference) 2H012 CD06 2H076 AA58 BA15 BA24 BA95 BA97 2H108 AA01 CB01 DA01 JA02 3F101 FB17 FD02 FD10 LA11 LB02 5B047 AA01 BA01 BB02 BC05 BC09 BC14 BC18 CB10 5C062 AA02 AA05 AB17 AB32 AB33 AB41 AB43 AC08 AD06 AA01 BA01 DA02 BA01 DA07 A

Claims (3)

[Claims] 1. A conveying means for conveying a document, and a slant disposed so as to face the document conveyed by the conveying means, and an upstream or downstream side of the conveying direction of the document by the conveying means being arranged at a high position. An image reading apparatus, comprising: a transparent member having a surface; and reading means for reading an image of a document conveyed on the transparent member. 2. The image reading apparatus according to claim 1, wherein a surface of the transparent member opposite to the inclined surface is arranged to be inclined in accordance with an inclination of the inclined surface. 3. The image reading apparatus according to claim 1, further comprising a magnification adjusting unit for adjusting a reading magnification of the reading unit in the main scanning direction.