JPH03129967A - Method for setting original read reference position - Google Patents

Abstract

PURPOSE:To automatically set an original position with high accuracy by utilizing a CCD sensor at the side of equipment main body and setting an original read reference position in the subscanning direction while compensating the position between the original and the equipment main body. CONSTITUTION:When an automatic original feeder B is loaded, a square hole 21 is searched while an optical read section 13 is moved in the subscanning direction. Then the movement of a read section 13 is stopped at the searched point of time and a CCD sensor 17 calculates a line bit number of the sensor 17 corresponding to the square hole 21 in the serial direction and the reference position between the equipment main body A and the original feeder B in the main scanning direction is set based on the bit number.

Description

Detailed Description of the Invention: Industrial Application Field The present invention relates to an optical reading device used as an image scanner, a copying machine, or a facsimile machine, and particularly relates to an optical reading device that is removable or has an automatic document feeder attached as an option. The present invention relates to an automatic document reading reference position setting method in a reading device.

"Prior Art" Conventionally, a document mounting table and an optical reading unit incorporating a linear light source, a CCD sensor, etc. that can move parallel to the document mounting table are provided, and a document is placed on the document mounting table. After that, while moving the optical reading section, the linear light source is irradiated onto the document surface, and optical information corresponding to the read image obtained is guided to a CCD sensor, and the optical information is sequentially converted into electrical signals by the sensor. Optical reading devices such as image scanners, copying machines, and facsimile machines configured to After installing the automatic document feeder on the placing table and fixing the optical reading section on the device main body side to a position where the document reading position provided in the document feeder can be read, the automatic document feeder side is placed on the document feeder side. The document reading device is configured to sequentially guide the documents stacked on the device to the document reading surface using a separating and feeding mechanism in the feeding device to read the documents.

``Technical problem to be solved by the invention'' Now, as mentioned above, when the document feeder is installed as an option or removably on the main body of the device, it is natural to avoid errors in installation between the two. For this reason, it is necessary to previously detect the positional error between the two before reading the original, and to provide a mechanism for compensating the reference position for reading the original based on the detected amount.

However, for example, providing a compensation mechanism consisting of a position detection means and an arithmetic circuit independently on the apparatus main body or document feeder side will complicate the configuration and increase the internal volume, resulting in miniaturization and reduction in manufacturing costs. Leads to.

However, such a positional error detection mechanism needs to be installed in a location that does not interfere with document reading, in other words, upstream of the document reading position, but even with this configuration, the accuracy may not necessarily be improved due to slippage of the rollers of the feeding mechanism, etc. For this reason, as shown in Figure 6, conventional devices are configured to take this positional error into account and instead of intentionally reading images from the periphery of the document, only the document in the center area is read. Was.

However, if an image also exists at the periphery of the document, such as in a catalogue, that portion will become white, which is undesirable.

For this reason, efforts have been made to place the position error detection mechanism near the document reading position, but it is quite difficult to install the detection mechanism at a location where it does not interfere with document reading, and it is difficult to install the detection mechanism in a location that does not interfere with document reading. Since the detecting means and the detecting means of the detecting mechanism are each constructed separately, the above-mentioned drawback cannot be overcome unless consistency is maintained between the two.

In view of the drawbacks of the prior art, the present invention automatically and accurately determines the document reference position by using existing members on the document feeder side and the device main body side, without providing an independent position error detection mechanism. The purpose is to provide a method to set the .

"Technical means for solving the problem" In order to achieve the technical problem, the present invention does not provide an independent detection means, but uses a CCD on the device main body side as a detection means.
Using sensors, especially CCD line sensors, while the C
Identification means is provided at or slightly upstream of the original reading position of the original reading reflection plate provided on the automatic document feeder side as a detection means of the CD sensor, thereby ensuring positional compensation between the original feeder and the main body of the apparatus. In addition, the CCD sensor detects the end of the document fed to the identification means side, thereby setting a document reading reference position particularly in the sub-scanning direction while compensating the position between the document and the main body of the apparatus. That is.

Also in the main scanning direction, as described in claim 6, the CCD line sensor forms the identification means with the CCD sensor, paying attention to the fact that line bits are arranged at high density in the main scanning direction. It is possible to detect the position and compensate for the position between the apparatus main body and the document feeder based on the number of line bits in the serial direction of the sensor corresponding to the detected position.

Therefore, according to the present invention, without providing an independent position compensation mechanism in both the sub-scanning direction and the main scanning direction, the identification means is simply mounted on the reflection plate on the document feeder side using the CCD sensor on the apparatus main body side. By providing this, it becomes possible to automatically and accurately set the document position.

Although the identification means generally uses a small diameter through hole in the shape of a square, circle, or diamond, it is not limited to this, and marking points formed on a reflector, LE
D may be formed from other light emitters.

The identification means is preferably formed at the document reading position in order to eliminate errors such as roller slippage on the document feeding mechanism side. When reading an image of a translucent original, the CCD may misread the shadow of the identification means through the original as an image.
Undesirable.

For this reason, in the invention described in claim 4, the image reading position and the detection position are separated, and the identification means is provided slightly upstream of the original reading position of the original reading reflection plate, so that the end of the original reaches the identification means. After detecting that the CCD
The above problem is solved by feeding the sensor and the original to the reading position and starting reading the original. In this case, since the formation position of the original identification means is slightly upstream of the original reading position of the original reading reflection plate, errors such as roller slippage can be substantially ignored.

Further, in the invention described in claim 5, although the identification means is provided at the image reading position, the square hole that functions as the identification means is closed, for example, using a shutter, etc., so that when the document is read, it is in a non-identification state. By configuring this, the above-mentioned drawbacks are solved.

In addition, in the case of a normal white document, when the document passes through the identification means such as the square hole, a change in light intensity occurs and can be detected on the CCD side, but in the case of a colored document, a catalog, or a solid black document, the above-mentioned identification is possible. Even when the light passes through the means, the amount of light does not change, and the effects of the present invention cannot be smoothly achieved.

Therefore, in the invention described in claim 3, in the case of the solid black original, the light amount does not change at the identification means portion, but the light amount changes at the positions of the reflecting plates on both sides in the main scanning direction. In this invention, the CCD sensor is used to detect changes in the amount of light on the reflecting plates located on both sides of the identification means adjacent to the identification means in the main scanning direction, thereby solving the above-mentioned drawbacks.

"Embodiments" Hereinafter, embodiments of the present invention will be described in detail by way of example based on the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. Not too much.

4 and 5 show an automatic document feeder incorporated in an image scanner according to an embodiment of the present invention, FIG. 4 is a front sectional view, and FIG. 5 is a document holder in which the feeder is incorporated. FIG. 2 is a perspective view of the plate 11 erected to expose the document reading reflective plate 20;

In FIG. 3, A is the scanner body, which includes an original platen 12 made of a transparent glass plate, and an optical scanner that can reciprocate in the sub-scanning direction (in the direction of the arrow in the figure, in the longitudinal direction of the original) parallel to the original platen 12. It is composed of a reading section 13. The optical reading section 13 corresponds to a linear light source 14 extending in the main scanning direction (document width direction) perpendicular to the moving direction, and a document image obtained by irradiating the document surface with the linear light source 14. A deflection mirror 15 that deflects the reflected light reflected by the deflection mirror 15, a focusing lens that guides the reflected light deflected by the deflection mirror 15 to a CCD sensor 17 while converging it, and photoelectric conversion of the linear optical information focused by the lens. If a COD line automatic document feeder is not installed, the electrical signal is output serially or in serial/parallel in correspondence with the number of line bits of the sensor 17, the document is placed on the placing surface. The operation when the optical reading unit 13 is moved from the home position in the sub-scanning direction after the scanning is performed will be explained in detail later.

Next, to briefly explain the internal structure of the automatic document feeder based on FIG. 4, on the right side of the figure is a paper feed tray 32 on which documents before image reading are loaded, and a document after image reading is loaded. Paper ejection trays 33 are arranged vertically and approximately parallel to each other, and an approximately C-shaped transport path is formed in the device in front of the paper ejection trays 33.
The CCD sensor 17 is moved by a separation feed roller 34, an intermediate roller 35, and a step motor 36, which separate and feed documents loaded on the paper feed tray 32 one by one into the conveyance path from the upstream side. A feed roller 38 capable of step feeding corresponding to the amount of paper, and a strip-shaped reflection strip for reading documents that faces the YX document placement surface 12a on the apparatus main body A side with a strip-shaped opening on the exit side of the feed roller 38 via a slit gap. It is composed of a plate 20 and a paper discharge roller 39 provided on the downstream side of the plate 20 at the entrance end of the paper discharge tray.

As shown in FIGS. 5 and 1, the document reading reflector 20 is arranged to extend in the main scanning direction by at least a length greater than the maximum reading width, and is slightly upstream from the document reading position. A small square hole 21 is bored on the side.

Note that the square hole 21 may be provided at a position where any size of document can be read, and the position in which it is attached in the main scanning direction is not particularly limited.

Next, Figures 1 and 2 show image reading operations when such an automatic document feeder is installed as an option.
This will be explained based on the diagram.

First, when you turn on the power of the device, the CCD sensor 17
The optical reading section 13 in which the is incorporated moves to the home position. (STEPI) and determines whether or not the automatic document feeder assistant is installed, and if it is installed, switches to ADF mode and performs the following operation, (5T
EP2) That is, first, the square hole 21 is searched while moving the optical reading section 13 in the sub-scanning direction. (STEP
3) Then, at the time of the search (X-α), the movement of the reading unit 13 is stopped, and the number n of line bits in the serial direction of the sensor 17 corresponding to the square hole 21 is calculated using the CCD sensor 17. Based on the bit number n, a reference position in the main scanning direction between the main body of the apparatus and the document feeder is set. (5TEP4) Next, turn on the automatic document feeder.
Set to N and feed the original 23. (5TEP5) When the document edge 23a reaches the starting end of the square hole 21 of the reflecting plate 20, the CCD sensor 17 detects the change in the light amount, thereby determining the reference position in the sub-scanning direction between the document and the main body of the apparatus. After the confirmation, the document 23 and the CCD sensor 17 are moved a predetermined distance α by each corresponding step motor to the reading position WX.
After moving, start reading the document.

(STEP 7) In this embodiment, the image reading position X and the detection position Hx-
α is separated and the square hole 21 is placed at the original reading position f! It is installed slightly upstream of Hx, and in order to confirm the reference position at this point, in other words, since there is no square hole 21 at the image reading position Hx, the image is read using thin paper or a translucent original. Even if this is done, no problem will occur. In this case, the original square hole 21 is formed at a position slightly upstream of the original reading position X of the original reading reflection plate 20, so that the feeding roller is Errors such as the above can be virtually ignored.

Further, when a square hole 21 is provided at the image reading position X, as shown in FIG. The rectangular hole 21 may be kept in a non-identifying state by opening the square hole 21 and closing it when reading a document. In this case, the detection operation and the reading start operation can be performed at the same point, which is preferable.

Note that in the case of a normal white original, the amount of light changes as the original passes through the square hole 21, which can be detected on the CCD side, but in the case of a colored original, a catalog, or a solid black original, the square hole 21. There is no change in the amount of light even when it passes through.

Therefore, in this embodiment, the CCD sensor 17 is used to detect changes in the amount of light at predetermined portions a and b of the reflection plate 20 located on both sides of the square hole 21 in the main scanning direction, as well as the square hole 21. ing. Such detection is easy because the CCD sensor 17 extends in the main scanning direction.

Incidentally, in the above embodiment, one identification means has been described as an example, but by using a plurality of identification means in the main scanning direction, it is possible to cope with the skew of the original and more accurately detect the edge of the original.

"Effects" As described above, according to the present invention, the document can be automatically and precisely detected by using existing members on the document feeder side and the device main body side, without providing an independent position error detection mechanism. In addition to being able to set the position, the present invention has various effects such as 0, which can easily achieve the above-mentioned effect even on the type of original, such as translucent or thin original, colored original, solid black original, etc.

[Brief explanation of the drawing]

1 to 5 show an optical reading device according to an embodiment of the present invention, FIG. 1 is an operational diagram thereof, FIG. 2 is a flowchart diagram, and FIG. 3 is a schematic diagram of a reflecting plate showing a modification thereof. FIG. 4 is a front cross-sectional view of the portion to which the document feeder is attached, and FIG. 5 is a perspective view showing the document holding plate 11 erected to expose the document reading reflector. FIG. 6 is a plan view of a document showing a readable area of a conventional document.

Claims (1)

[Claims] 1) A method and method for setting a document reading position in an optical image reading device comprising a device main body incorporating a CCD line sensor and a document feeder installed on the document placement surface of the device main body. A CCD sensor on the main body side of the apparatus is used as a detection means, and at least one sensor is used at the original reading position of the original reading reflection plate provided on the automatic document feeder side or slightly upstream thereof as a means to be detected by the CCD sensor. Reference position setting method 2) characterized in that a document reading reference position in the sub-scanning direction is set by providing two identification means and having the CCD sensor detect the edge of the document fed to the identification means side. A document feeding device configured such that a document can be fed to the document placement surface side of a reflection plate for document reading in an apparatus main body in which a CCD line sensor for optical reading is movably incorporated in parallel to the document placement surface. In the document reading position setting method in an optical image reading device equipped with
Using a D sensor, detecting a change in the amount of light that occurs when the edge of the document fed from the feeding mechanism reaches the identification means,
3) A document reading position setting method characterized by setting a document reading position in the sub-scanning direction based on the detection signal. 3) When the document end is reached, at least one of the parts in the main scanning direction adjacent to the identifying means together with the identifying means 2. The apparatus according to claim 2, wherein the CCD sensor is used to detect a change in the light amount of a reflecting plate located on one side, and a document reading reference position in the sub-scanning direction is set based on these detection signals.
) Document reading reference position setting method 4) After providing the document reading reflector slightly upstream of the document reading position and detecting that the document edge has reached the identification means using the CCD sensor. , the CCD
5) The document reading reference position setting method according to claim 2), characterized in that the sensor and the document are each sent to the reading position and document reading is started. A discriminating means that can be changed is provided, and after detecting that the edge of the document reaches the discriminating means using the CCD sensor, the discriminating means is changed to a non-discriminating state and reading of the document is started. 6) The document reading reference position setting method according to claim 2), characterized in that the CCD line sensor for optical reading is incorporated in the apparatus main body movably in parallel with the document placement surface, and In a method for setting a document reading reference position in an optical image reading device equipped with a document feeding device configured to feed a document on the document placement surface side, A reference position characterized in that the provided identification means is detected by a CCD sensor on the apparatus main body side, and a document reading reference position in the main scanning direction is set based on the number of line bits of the sensor corresponding to the detected position. Setting method