JPH08304940A - Image reader - Google Patents

Abstract

PURPOSE: To provide an image reader capable of surely detecting the set position of an original and the size of the original. CONSTITUTION: This reader is equipped with an original cover plate covering the original 1 on an original platen, an illumination means illuminating the read part of the original 1, and a detection means receiving reflected light from the original surface being the irradiating light radiated to the original 1 by the illumination means. The illumination means is constituted of a light emitting part 3a arranged at a lower part in the original platen and a lens provided in front of the light emitting part 3a and radiating the light emitted from the light emitting part 3a to a specified area; and the detection means is constituted of a lens 3d receiving the reflected light from the illuminated original 1 and a photodetector array 16 detecting the point of the center of gravity G of received light quantity, and equipped with a CPU and a control part 18 detecting the size of the original and the placing position of the original by comparing the detection information inputted from the array 16 with original size information stored previously.

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 for reading an original placed on an original placing table, and more particularly to detecting the size of an original and detecting the deviation of the original from the original placing reference position. The present invention relates to an image reading device.

[0002]

2. Description of the Related Art In order to maintain a constant relative positional relationship between a reading means and an original when reading an image on the original,
Generally, the reference position of a document is determined. For example, in some copying machines, the end portion of the document table is set at the reference position of the document. In this type of copying apparatus, an original detection device is arranged in the optical system so as not to come into contact with the exposure optical path, the lens, the mirror, or their driving mechanism in the optical system. In this document detection device, the size of a document placed on the document table is sampled from the outputs of a plurality of document detection sensors based on the closing operation signal of the document pressing plate, and the document size is reflected from the combination of outputs. It has become. Therefore, in order to detect and determine various document sizes, a plurality of document detection sensors are arranged at preset positions. Each of these document detection sensors includes a light emitting unit and a light receiving unit that form a pair, irradiates the document surface with illumination light from the light emitting unit, and receives reflected light (scattered light) from the illumination light from the document surface side. It is designed to receive light. And
The light receiving signals from the plurality of document detection sensors are respectively determined based on the values set in the control unit, and the document size is determined based on the combination result of the document signal and the recognized signal.

In order to improve the detection accuracy on the document surface, the illumination intervals on the document surface are arranged close to each other. However, if they are too close to each other, the light reflected by the adjacent document detection sensor will be reflected by another document detection sensor. May be incident on or may affect the detection level, resulting in erroneous detection. In order to prevent erroneous detection or to minimize the influence from the adjacent light emitting units, the illumination interval on the document surface, in other words, the interval between the light emitting units must be at least 10 mm. When the light emitting units are arranged at such an interval, the detection performance can be obtained only to the extent that the standard size can be detected.

When the outputs of a plurality of document detecting sensors are sampled based on the size of the document placed on the document platen based on the closing operation signal of the document pressing plate as described above, the detection sensitivity region and the document pressing plate. The relationship of the closing signal of is that the closing angle that can reliably detect the original stacked on the original table is set at the position where the sheet surface of the original pressing plate is not detected.
The detection timing of the document detection is set based on this angle.

[0005]

By the way, the original is set by abutting the end of the original against the original scale of the original table, and the original is set apart from the original scale or slightly. Even if the sheet is set in a slanted state, the variation state of the set state is not detected, and a copy image is formed as it is set on the document table.

Further, in order to detect accurately, the detection area may be set in a wide range and a large number of sensors may be provided.
The cost increases accordingly.

The present invention has been made in view of the above-mentioned circumstances of the prior art. A first object of the present invention is to reliably detect the set position and size of a document even if it is of an irregular type. An object of the present invention is to provide a low-cost image reading device.

It is a second object of the present invention to provide an image reading apparatus capable of automatically correcting the misalignment when the misalignment of the document set position is detected to minimize copy mistakes.

A third object of the present invention is to provide an image reading apparatus which can display the size of the original document, the deviation of the original document and the like to minimize the operator's copy mistake.

[0010]

In order to achieve the first object, the first means is an original pressing plate for pressing an original on an original table, an illuminating means for illuminating a reading portion of the original, and an illuminating means. In an image reading apparatus having a detection means for receiving the reflected light from the original surface of the irradiation light applied to the original by the light source, the illuminating means is disposed in the lower part of the original table, and the front of the light emitting portion. And a lens for irradiating the light emitted from the light emitting portion to a predetermined area, and a lens for receiving the reflected light from the illuminated document and the center of gravity of the received light. And a control means for detecting the size of the document and the placement position of the document by comparing the detection information input from the detection means with the document size information stored in advance. Featuring To have.

In order to achieve the above-mentioned second object, a second means is an image reading apparatus of the same premise, and in the image reading apparatus, the illuminating means is arranged in the lower part of the document table, and a light emitting part is provided in front of this light emitting part. And a lens for receiving the reflected light from a document illuminated by the detecting means and a light receiving device for detecting the center of gravity of the received light amount. It is characterized in that it comprises an element and further has a control means for changing the control reference for image formation by comparing the detection information input from the detection means with the document size information stored in advance.

In order to achieve the second object, the third means is an image reading apparatus of the same premise, and in a similar image reading apparatus, the illuminating means is arranged in a lower portion of the document table, and a front portion of the light emitting portion. A lens for receiving the reflected light from the document illuminated by the detecting means and a light receiving element for detecting the center of gravity of the received light. Further, it is characterized in that control means for changing the control reference of the lateral registration of image formation by comparing the detection information input from the detection means with the document size information stored in advance is provided.

In order to achieve the first and second objects, the fourth means is the first to third means, and in the first to third means, the illuminating means is arranged in the width direction of the document along the document scale serving as a reference for placing the document. And the detection means are arranged in the width direction and the length direction of the document along the document scale on which the light reflected by the illumination means can enter.

In order to achieve the third object, the fifth means further comprises a display means in addition to the first to third means, and the control means displays the detection information input from the detection means. It is characterized by being displayed on.

An image reading apparatus according to any one of claims 1 to 3.

In order to achieve the first and second objects, the sixth means is characterized in that the light receiving element is composed of a PSD element.

[0017]

According to the first means, the illumination light emitted from the light emitting portion is reflected by illuminating the original detection area, and the reflected light is condensed by the lens and is incident on the light receiving element and received by the light receiving element. The control means detects the barycentric position of the light quantity, compares the barycentric position information with the previously stored document size information, and detects the size of the document and the document placement position.

According to the second means, the center of gravity position of the amount of light is detected by the light receiving element similarly received, and the control means compares the information of the center of gravity position with the information of the document size stored in advance. The control reference for forming an image is changed according to the position of the original.

According to the third means, the center of gravity position of the amount of light is detected by the light receiving element similarly received, and the control means compares the information of the center of gravity position with the information of the document size stored in advance. The control reference of the lateral registration is changed when the image is formed according to the position of the original.

According to the fourth means, the illuminating means and the detecting means are arranged at a position along the original scale, and the edge of the original is surely secured in the vicinity of the original scale where the edge of the original is likely to be located. To detect.

According to the fifth means, the control means causes the display means to display the detection information of the document input from the detection means,
Inform the operator about the state of the document and changes in the control criteria when the image of the document is formed. This allows the operator to
The necessary treatment can be taken, and the treatment can be performed efficiently.

According to the sixth means, since the detecting means is constituted by the PSD element, the barycentric position of the incident light quantity can be easily detected.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a structure of a main part of an image reading apparatus according to an embodiment, and FIG. 2 is a plan view of a document table showing an arrangement of a detection device. In these figures, for example, an image reading device 100 of a copying machine is shown in FIG.
And the document detection sensors 3 and 4 provided below the document table 2.
And a document pressing plate 8 for pressing the document 1 placed on the upper surface of the document table 2 from above. The document pressing plate 8 is cantilevered and rotatably supported by the support shaft 8a, and the closing switch 9 detects a predetermined opening / closing angle of the document pressing plate 8. That is, as shown in FIG. 1, when the opening / closing switch 9 is closing in the opening direction to the closing direction, an operation signal (ON) is generated when a predetermined angle θ is reached.
Is output. In a control unit 18 shown in FIG. 4 which will be described later, the CPU 19 shown in FIG. 5 reads the output signals of the document detection sensors 3 and 4 based on this operation signal to determine the size of the document.

In FIG. 1, the document detecting sensors 3 and 4 constitute a single sensor in which the light emitting portions 3a and 4a and the light receiving portions 3b and 4b form a pair, and the light receiving portions 3b and 4b correspond to the light emitting portions 3a and 4a. The reflected light (scattered light) of the emitted light emitted from is detected. These document detecting sensors 3 and 4 have many size end portions so that a specific size of the document can be detected.
The detection ranges 12a, 12b, 12c, 1 at positions along 0
3a and 13b are provided. The manuscript scale 10 is for determining the reference position of the manuscript, and as can be seen from FIG. 2, the upper part 10a in the drawing orthogonal to the main scanning direction.
And a portion 10b on the left side in the drawing parallel to the main scanning direction is formed into a hook shape, and the portion on the side of the document table 2 at the intersection of the two becomes the document reference position (document placement reference position) 11. The detection ranges 12a, 12b and 12c are provided along the upper original scale 10a in the figure, and the detection ranges 13a and 13b are provided along the left original scale 10b in the figure.

The document detecting sensors 3 and 4 are provided at preset positions below the document table 2 as shown in the schematic explanatory view of the main parts of FIG. In addition to the portion 3b, a cylindrical lens 3c is further provided on the front surface of the light emitting portion 3a in the light irradiation direction so that the irradiation light emitted from the light emitting portion 3a becomes parallel light and is uniformly illuminated in the detection area of the document surface. There is. It should be noted that the drawing shows a state where parallel light is not used for convenience of illustration. In this case, the emitted light does not necessarily need to be parallel light, and may be diffused light as long as it is not attenuated when entering the light receiving element and cannot be detected. The light applied to the document surface is condensed by the lens 3d provided in the front portion of the detection device as reflected light and scattered light on the document surface, and enters the light receiving portion 3b. The light incident on the light receiving portion 3b is incident on the light receiving element array 16 including PSD elements as shown in FIG. 4 which is a block diagram of the document detection process. Each light receiving element array 16
An amplifier circuit 17 is connected to the control circuit 18 and the received light signal is amplified to the processing level of the control section 18 and taken into the control section 18. The captured detection data is determined as document position data and document size data, which will be described later, based on a preset program. It should be noted that the document detection sensor is provided with one PDS element corresponding to each detection range, and in the example of FIG. 2, since five detection ranges are provided, the document detection sensor also corresponds to this. Individual pieces (3, 4, 5, 6, 7) are provided. Further, in this embodiment, the detection ranges are set at five places, but the positions and the number of these detection ranges are appropriately set according to the size and type of the document read by the reading device used.

The document size includes a plurality of detection ranges 12a, 1
It is determined by combining the detection outputs of the document detection sensors 3, 4, 5, 6, 7 in 2b, 12c, 13a, 13b. The combination of the detection ranges is executed by the combination of the detection on the width side and the detection on the length side of the document. Therefore, in this embodiment, the detection ranges 12a, 12b, 12c set on the original scale 10a side and the detection ranges 13a, 13b set on the original scale 10b side are used. Thus, for example, when the width of the document is detected in the detection range 12a, the length of the document is detected in the detection ranges 13a and 13b, and when the width of the document is detected in the detection ranges 13a and 13b, the detection ranges 12a, 12b and 12c are detected. Detects the length of the document. In this case, the adjacent detection ranges are arranged at intervals, but this is because the size detection can be performed by the detection output of both detection ranges without directly detecting the ends between them. In addition, in FIG. 4, the irradiation area by the cylindrical lens 3c is defined so that the illumination range 14 by the irradiation light emitted from the light emitting unit 3a includes at least the detection area 12a with respect to the detection area 12a by the light receiving element array 16. .

FIG. 5 is a control block diagram of the image reading apparatus according to the embodiment. As can be seen from the figure, detection output from the document detection sensors 6 and 7 on the width side (document scale 10b side) of the document 1 and detection from the document detection sensors 3, 4 and 5 on the length side (document scale 10a side) The output is obtained by the PSD element of the light-receiving element array 16 together with the angle detection output from the closing switch 9 as described below with respect to the center of gravity G (FIG.
(See (b)) is detected, and the edge position of the document is determined by this. The CPU 19 executes a determination process based on a predetermined control procedure described later, and displays it on the operation display unit 20.

As the processing of the CPU 19, there is a main processing as shown in the flowchart of FIG. That is, when the power of the copying machine is turned on (S1), the main body CPU 19 initializes (S2) and shifts to the normal mode (S3). In the normal mode, key input on the operation display unit and copy operation are performed. In this normal mode, the document size detection and the document shift detection, which are the subject of the present application, are performed.

In the document size detection process, as can be seen from the flowchart of FIG. 7, first, in step S11, it is determined whether the closing switch 9 is turned on, in other words, whether the document pressing plate 8 is closed from the upper side to a predetermined angle θ. It is determined (S11), and when the document pressing plate 8 has passed the predetermined angle θ, the ON range check of the first document detection sensor 3 on the length side of the document is executed (S12), and then the second and the following. An on-range check of the third document detection sensors 4 and 5 is executed (S13). Further, the ON range of the first document detection sensor 6 on the width side and the ON range of the second document detection sensor 7 on the width side are checked (S14, S15).
Then, by this check, the document size confirmation process (S
16) is performed. This process is executed every time the document pressing plate 8 is opened and the document 1 is replaced. That is, as described above, one PSD element is arranged in one length sensor, and when the PSD element output is turned on for the first time, the center of gravity G is output from the PSD element. The edge of the document 1 is detected from the relationship shown in FIG. In the check of the first document detection sensor 3, it is checked how much the document is displaced from the reference end face (document scale 10b) side. With respect to the document detection sensors 6 and 7 on the width side, the sensor-on range is checked by the same procedure, and the document size is determined.

In this case, the length of the original is detected from the rear end position of the original of the second or third original detecting sensor 4 or 5 on the length side and the front end position of the original of the first original detecting sensor 3 on the length side. To be done. Further, the registration amount of the leading edge of the original can be corrected by the amount of deviation of the leading edge position of the first original detection sensor 3 on the length side from the original scale 10b.

For example, the detection position in the lengthwise direction of the first document detection sensor 3 is a reference position (for example, the document scale 1).
If the position is 0 mm from 0b), the document registration position on the image formation is 10 m in the vertical direction (sub-scanning direction) from the reference position.
Control is performed so that copying is performed while shifting the distance. Further, if the document length is detected by a sensor that detects the rear end side of the document, for example, the second document detection sensor 4 on the length side, the second
The displacement amount A from the center point of the original document detection sensor 4 and the displacement amount B from the center point of the first document detection sensor 3 on the length side are
And the sum of the center distances L of 3 and 4 of the second document detection sensor, that is, document length = L + A + B (1) (where A and B are +, − from the center point of the document detection sensor).
It is represented by. ).

After the document size is determined, it is determined whether or not the document 1 is away from the regular setting position. In this case, the normal vertical position of the document 1 in the control, in other words, the vertically set position of the document 1 is set to C. Then, if the center of gravity G of the ON signal of the first document detection sensor 3 on the length side is 10 mm, the transfer paper is moved 10 mm rearward from the reference position A to start reading the document 1 and make a copy. Control to run. That is, the transfer amount of the transfer sheet = C + (the position of the center of gravity of the first document detection sensor 3 on the length side) (2) is determined, and the copy control is performed. In this method, the center of gravity G of the first original detection sensor 3 on the length side is read to detect the registration position and the transfer paper is moved. However, instead of this method, the starting position on the scanner side is corrected. You can also choose to do so.

Here, the principle of position detection of the document detection sensor composed of a PSD element will be described. First, as shown in FIG. 8, the PSD element is composed of three layers, that is, a P layer formed on the front surface of a flat plate-shaped silicon, an N layer formed on the back surface, and an I layer formed between the both. . Then, the light incident on the PSD element is photoelectrically converted, and is split and output from the electrode connected to the P layer as a photocurrent. In addition,
In the double-sided split type, split output is performed from the electrodes connected to the P layer and the N layer.

When a light spot is incident on the PSD element constructed as described above, a charge proportional to the light energy is generated at the incident position. The generated charges pass as a photocurrent through the P layer (resistive layer) and are output from the electrodes. Since the P layer (resistive layer) is formed so as to have a uniform resistance value over the entire surface,
The photocurrent is divided and extracted in inverse proportion to the distance (resistance value) to the electrode. Here, if the distance between the electrodes is S, the photocurrent is I ₀ , and the currents extracted from the electrodes are I ₁ and I ₂ , (I ₂ −I ₁ ) / (I ₁ + I ₂ ) = 2X / S ... (3) Since the incident position of the light spot is obtained by this formula, the original position on the contact glass (original table 2) can be obtained by enlarging this value according to the contraction rate of the lens. Therefore, unlike the conventional case, it is possible to detect a continuous area without requiring a long interval between the adjacent sensors, and therefore, there is no erroneous detection due to the interval between the sensors.

The X position in the equation (3) is PS
Since it is the position of the aforementioned center of gravity detected by the D element,
The positions of the points A and B in the equation (1) are the positions of (S / 2 + X) / 2 (4), and the position of the document edge can be reliably detected.

In this way, it is possible to reliably detect the state where the document is separated from the document scale 10 or the state where the document is set obliquely, and it is possible to prevent the document from being set or copied incorrectly, or from being badly copied. You can Also,
Since the sensor is planar and can detect the size of the placed document as a continuous area, it is possible to select an appropriate copy sheet corresponding to the document.
Further, not only the standard size but also the size of the irregular size document can be detected, and the accuracy of the size detection of the document can be improved. In addition, since the sensor in one detection area can also detect the state of setting the document and the size, the cost of the detection means can be reduced, and the image reading apparatus can be provided at low cost. Since the set state of the document is displayed, it is possible to confirm the operation content and prevent an operation error.

In the above embodiment, the control reference of the original is changed only in the lengthwise direction of the original, but the original is placed with the original scale 10a displaced as shown in FIG. It can happen. In such a case, the image forming position is automatically corrected based on the detection output of the original detection sensor on the width side so that the image is formed.

That is, in the embodiment, the first in the width direction
When the document detection sensor 6 detects the edge of the document, the detection range of the document detection sensor 6 is 1 from the reference position.
If it is at the position of 0 mm, it means that the end portion on the width side of the document is separated from the side of the document scale 10a by, for example, 10 mm,
Copy control may be performed by shifting the document lateral registration position on the image in the width direction (main scanning direction) from the reference position (position of the document scale 10a) in the main scanning direction by 10 mm. This copy control is performed according to the preset program C
It is executed by the PU 19. By doing so, the deviation from the reference position in the width direction (main scanning direction) of the document is automatically corrected, and therefore it is possible to prevent the generation of a defective copy image due to a document setting error.

More specifically, after the document size is determined, it is determined whether the document is away from the regular set position, and the lateral position of the regular set document in the control is W.
The end surface of the ON signal of the first document detection sensor 6 in the width direction is 1
If it is 0 mm, the lens movement amount = W + the end face position of the first document detection sensor in the width direction (5), and the lens is moved 10 mm before the reference W position to start reading the document. Perform copy control. In this embodiment, the barycentric point of the first original detection sensor 6 in the width direction is read to detect the lateral registration position, and the lens is moved in the main scanning direction based on the detection result. It can also be configured to correct the lateral position on the side.

Therefore, as described above, the deviation in the sub-scanning direction and the deviation in the main-scanning direction as described above are detected and automatically corrected to minimize the occurrence of a copy image due to a document setting error. Can be suppressed.

[0041]

As is apparent from the above description, the present invention configured as described above has the following effects.

Illumination means comprising a light emitting portion arranged in the lower part of the document table and a lens provided in the front part of the light emitting portion and irradiating the light emitted from the light emitting portion to a predetermined area, and illumination means. And a detection unit composed of a lens for receiving the reflected light from the original and a light receiving element capable of detecting the center of gravity of the received light, the detection information input from the detection unit, and the original size information stored in advance. According to the invention of claim 1, further comprising: a control unit for reading the document by comparing the document size and the document placement based on the center of gravity of the amount of light incident on the light receiving element. Even in the case of the size, the document size and the document placement position can be detected reliably and accurately. Further, since no means for detecting the placement position of the original is required, cost reduction and space saving can be achieved.

The invention according to claim 2, further comprising control means for comparing the detection information input from the detection means with the document size information stored in advance to change the control reference for image formation. Since the positional deviation of the document placement position from the normal position is detected from the detection information of the detection means, and the image formation control reference is changed based on the positional deviation,
In addition to the effect of the first aspect of the invention, even if the placement position of the document is deviated from the regular position, the misregistration can be automatically corrected to minimize miscopy.

According to the invention of claim 3, further comprising control means for comparing the detection information input from the detection means with the document size information stored in advance and changing the control reference of the lateral registration for image formation. 2. The invention according to claim 1, wherein the deviation of the placement position of the document from the normal position in the lateral registration direction is detected from the detection information of the document detection means, and the control reference for image formation is changed based on the position shift. In addition to the effect of (1), even if the lateral registration of the original placement position is deviated from the normal position, the misregistration can be automatically corrected to minimize miscopy.

The illuminating means is arranged in the width direction and the length direction of the original along the original scale as a reference for placing the original, and the detecting means is arranged along the original scale on which the light reflected by the illuminating means can enter. According to the invention described in claim 4, which is arranged in the width direction and the length direction of the document, the detection area is set at a position where there is a high probability that the edge of the document is located. Can be detected.

According to the invention of claim 5, wherein the detection information inputted from the detection means is displayed on the display means, when the original is not set at the proper placement position, the fact is displayed, so that the operator , It becomes possible to take the necessary action by looking at the display, and thereby the miscopy can be minimized.

According to the invention of claim 6, wherein the light receiving element is a PSD element, it is possible to easily detect the barycentric position of the incident light amount from the detection output of the element, so that the edge of the document can be detected with high accuracy. Will be possible.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a relationship between a document placing table and a detection range according to the embodiment.

FIG. 3 is a schematic configuration diagram showing a configuration of a detection sensor of the image reading apparatus according to the embodiment.

FIG. 4 is an explanatory diagram showing the principle of document reading by the image reading apparatus according to the embodiment.

FIG. 5 is a block diagram showing an electrical configuration of the image reading apparatus according to the embodiment.

FIG. 6 is a flowchart showing a processing procedure in a main processing of the CPU of the image reading apparatus according to the embodiment.

FIG. 7 is a flowchart illustrating a processing procedure of document size detection of the CPU of the image reading apparatus according to the embodiment.

FIG. 8 is an explanatory diagram showing a detection principle of a document detection sensor of the image reading apparatus according to the embodiment.

FIG. 9 is an explanatory diagram showing a relationship between an original detection sensor ON of the image reading apparatus and an edge position of the original according to the embodiment.

FIG. 10 is an explanatory diagram showing a method for correcting a lateral registration shift in the image reading apparatus according to the embodiment.

[Explanation of symbols]

1 original 2 original table 3, 4, 5, 6, 7 original detection sensor 3a, 4a light emitting part 3b, 4b light receiving part 3c, 3d lens 8 original pressing plate 9 closing switch 10, 10a, 10b original scale 11 original reference position 12a , 12b, 12c, 13a, 13b Document detection range 16 Light receiving element array (PSD element) 17 Amplifying circuit 18 Control unit 19 CPU 20 Operation display unit 100 Image reading device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadayuki Sekiya 1-3-3 Nakamagome, Ota-ku, Tokyo Stock company Ricoh Company (72) Toru Kamiyama 1-3-6 Nakamagome, Ota-ku, Tokyo Share Company Ricoh

Claims (6)

[Claims] 1. A document pressing plate for pressing a document on a platen, an illuminating unit for illuminating a reading portion of the document, and a detecting unit for receiving reflected light from the document surface of the illuminating light applied to the document by the illuminating unit. In the image reading apparatus having the above-mentioned, the illuminating unit is a lens which is provided in a lower portion of the document table and a front portion of the light-emitting unit, and which illuminates light emitted from the light-emitting unit to a predetermined area. The detection means is composed of a lens for receiving the reflected light from the illuminated original document and a light receiving element for detecting the center of gravity of the received light amount, and the detection information input from the detection means and An image reading apparatus comprising: control means for detecting the size of a document and the placement position of the document in comparison with the stored document size information. 2. A document pressing plate for pressing a document on a platen, an illuminating unit for illuminating a reading portion of the document, and a detecting unit for receiving reflected light from the document surface of the illuminating light applied to the document by the illuminating unit. In the image reading apparatus having the above-mentioned, the illuminating unit is a lens which is provided in a lower portion of the document table and a front portion of the light-emitting unit, and which illuminates light emitted from the light-emitting unit to a predetermined area. The detection means is composed of a lens for receiving the reflected light from the illuminated original document and a light receiving element for detecting the center of gravity of the received light amount, and the detection information input from the detection means and An image reading apparatus comprising control means for changing a control reference for image formation in comparison with stored document size information. 3. An original pressing plate for pressing an original on the original table, an illuminating means for illuminating a reading portion of the original, and a detecting means for receiving reflected light from the original surface of the illuminating light applied to the original by the illuminating means. In the image reading apparatus having the above-mentioned, the illuminating unit is a lens which is provided in a lower portion of the document table and a front portion of the light-emitting unit, and which illuminates light emitted from the light-emitting unit to a predetermined area. The detection means is composed of a lens for receiving the reflected light from the illuminated original document and a light receiving element for detecting the center of gravity of the received light amount, and the detection information input from the detection means and An image reading apparatus comprising control means for changing a control reference of a lateral registration for image formation in comparison with stored document size information. 4. The manuscript scale, wherein the illuminating means is arranged in a width direction and a length direction of the manuscript along a manuscript scale as a reference for placing the manuscript, and the detecting means allows the light reflected by the illuminating means to enter. 4. The documents are arranged in the width direction and the length direction of the document along the line.
The image reading device according to any one of 1. 5. The display device according to claim 1, further comprising a display unit, wherein the control unit displays the detection information input from the detection unit on the display unit.
4. The image reading device according to any one of 3 to 3. 6. The image reading apparatus according to claim 1, wherein the light receiving element is a PSD element.