JPH1051600A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of useless operations or times by preventing error interruption after prescanning by providing a detecting means for detecting whether or not an original is placed at a proper position. SOLUTION: Near a stopper 5 on an original platen 1, a photosensor 11 is provided for detecting whether or not the original is set at the proper position. A pair of such photosensors 11 are provided at the left and right symmetric positions on the original platen 1. When a book as the original is pressed tightly to the stopper 5, the book covers two photosensors 11 so that both the photosensors 11 are turned on. When only one of the photosensors 11 is turned on, it is judged the book is placed while being inclined, and a required message is displayed. Only when it is judged that the original is placed properly, is the prescan operation started, so that error interruption after the prescan operation as in the conventional system can be prevented.

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 a document such as a book from above with the document opened, and more particularly to a technique for detecting whether a document is placed at a predetermined position without tilting.

[0002]

2. Description of the Related Art Conventionally, in an image reading apparatus of this type (referred to as a book scanner or the like), when a book document or the like placed in a spread state on a document table is photographed and read from above, the height of the document is high. In some cases, the image distribution is measured to correct the curvature of the read image, etc., to reproduce the image correctly (for example, Japanese Patent Application Laid-Open Nos. 3-117965 and 5-5-).
No. 316302). Since a distance measuring mechanism such as a distance measuring mirror is used as a means for measuring the height distribution of the original, the original must be correctly placed at a predetermined position on the original platen for accurate height measurement. Therefore, a stopper serving as a positioning reference for that purpose must be provided on the document table, and the document must be placed so as to be pressed against the stopper. The height measurement and the inclination detection of the original are performed by detecting the contrast between the original and the platen and the outer frame shape of the original from the image data obtained by pre-scanning the original by the imaging means of the apparatus. After can
The original is read by the main scanning operation.

[0003]

However, in the conventional apparatus as described above, when the original is not set at a correct position (that is, when the original is not correctly pressed against the stopper), the pre-scan is performed. Since the height of the original cannot be measured correctly from the obtained data and a distance measurement failure occurs, the operation is interrupted by an error after the pre-scan and the operation does not proceed to the main scan. Also, even when the original is placed at an angle, the warning (error) ends because the correction of the curvature of the image data and the correction of the shrinkage of the character in the main scan cannot be performed accurately. As described above, since the conventional apparatus does not have a means for detecting whether or not the original is correctly placed before the pre-scan, the operation is interrupted halfway after the pre-scan is performed. In such a case, it is necessary to re-place the original document and perform a restart operation, which is time-consuming and cumbersome.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is an object of the present invention to detect whether or not a document is correctly placed on a document table and notify a user before a prescan. It is therefore an object of the present invention to provide an image reading apparatus in which an error is not interrupted after the pre-scan so that useless operation and time are prevented from occurring.

[0005]

According to an aspect of the present invention, there is provided an image reading apparatus for reading a manuscript such as an open book which is placed on a manuscript table. Reading means for reading a document placed on the document table and outputting image data, a stopper provided on one side of the document table as a reference for positioning the document, and provided near this stopper so that the document is placed at a correct position. Detecting means for detecting whether or not the original is placed, and a warning means for issuing a warning when it is determined that the document is not placed at a correct position based on a detection signal from the detecting means.

In the above arrangement, when a document is placed on the document table, whether or not the document is correctly placed with respect to the stopper is detected by a signal from detection means provided near the stopper. If not, a warning will be issued. Since this warning is issued before the start of the scanning operation for reading, the operation does not stop after the pre-scanning.

According to a second aspect of the present invention, in the configuration described in the first aspect, the detecting means is a sensor or a switch provided at least at each of right and left target positions on the document table. In the above configuration, if neither of the two sensors or the switches outputs the document detection signal, it can be surely confirmed that the document is not placed exactly against the stopper without tilting before the start of the prescan. Thus, the above-described operation is obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a book scanner which is an embodiment of the image reading apparatus of the present invention. In this apparatus, a scanner unit 2 (reading means) for reading an image by optically operating (scanning) a document with a predetermined work space on a document table 1 is arranged. The scanner unit 2 includes a CCD line sensor and the like. A lamp unit 3 for illuminating the original is provided below and behind the scanner unit 2, and a distance measuring plate 4 is provided in the back of the original table 1. Is provided. The lower end of the front edge of the distance measuring plate 4 forms a stopper 5 for positioning and placing a book document or the like. The upper end of the distance measuring plate 4 is white, and serves as a shading plate 6 for performing shading correction during reading operation in the sub-scanning direction. A control unit 7 having an operation panel such as a liquid crystal display for notifying the user of various information and messages to the user and controlling the entire apparatus is provided behind the distance measuring plate 4. A start key (print button) 8 for starting a reading operation is embedded on the document table 1, and a main switch 9 is disposed on a side surface.

Image data photographed by the scanner unit 2 of the apparatus is subjected to various processes by the control unit 7 and output to a desired output device such as a printer. Since the side of the document placed on the platen 1 is reflected on the distance measuring plate 4,
By reading the image of the distance measuring plate 4 during the pre-scan operation, the height of the document can be detected. Prior to the reading operation, the control unit 7 determines whether or not the original is correctly placed based on an output of a photo sensor 11 described later, and drives the liquid crystal display of the operation panel according to the result. A message prompting the user to replace the original, thereby functioning as a warning unit.

FIG. 2 is a plan view of the document table 1 of the present apparatus as viewed from directly above. The stopper 5 in the figure is a guide plate for exactly fitting the book document to the distance measuring plate 4, and the book document is pressed in parallel with the distance measuring plate 4 by pressing the book document against the stopper 5, so that the book document is correctly placed. Document height measurement (ranging) can be performed. In the vicinity of the stopper 5 on the document table 1, a photo sensor (detection means) 1 for detecting whether or not the document is placed at a correct position.
1 is provided. This photo sensor 11 is a platen 1
A pair is provided at the upper left and right target positions.

The photo sensor 11 needs to be provided so as to correspond to the shape of a book document (book) of various sizes. FIG. 3 is a diagram illustrating an arrangement configuration of the photosensor 11. Since the book has a symmetrical shape when opened, the photosensors 11 are desirably arranged symmetrically about the center of the document table 1. Even when three or more photosensors 11 are used, it is desirable to arrange them symmetrically. Note that even when the smallest supposed book (shown by a broken line) is placed, it is necessary that at least one left and right photosensors 11 be placed below the book. Also, the photo sensor 1
In the case where there are two (one each on the left and right), if the photo sensor 11 is provided extremely near the center of the document table 1, the accuracy of detecting the inclination of the book is reduced. It is necessary to arrange the sensor 11 at a position that covers the sensor 11 barely. In the figure, "l" + "L" may be the minimum assumed book size, and increasing "l" as much as possible improves the accuracy of tilt detection. Therefore,
“L” is made as small as possible in consideration of an error in the position where the user places the book.

Next, a case where a document is correctly placed on the document table 1 and a case where the document is placed at an angle will be described with reference to FIG. As shown in FIG. 4A, when the book is pressed tightly against the stopper 5, the book covers the two photosensors 11 so that both the photosensors 11 are covered.
Turns ON. When the book is placed at an angle as shown in FIG. 4B, one of the photosensors 11 is turned off.
It is understood that it is placed at an angle. When the book is placed away from the stopper 5, both the photo sensors 11 are turned off. As described above, by providing two or more photosensors 11 near the stopper 5 at right and left sides, it is possible to determine whether or not the book is placed at the correct position. Note that a mechanical switch can be used instead of the photo sensor 11.

FIG. 5 is a flowchart of an operation for detecting the placement state of a document in the apparatus according to the present embodiment. When the start key 8 is pressed, the control unit 7 causes the lamp unit 3 to emit light, the illumination light is applied to a book placed on the document table 1, and the reflected light is read as an image by the scanner unit 2. Prior to the operation, the control unit 7 determines whether the operation mode of the apparatus is the book mode or the sheet mode (# 1). This mode has been selected by the user in advance. In the image reading operation, a pre-scan is performed to measure the height of a document for correcting image bending, and the image data is read in a main scan.

When the sheet mode is selected (# 1)
NO), the original is not a double-page spread, and there is only an original on one side of the center of the original platen 1 (for example, when a vertical original is placed on the left side). No. In the sheet mode, since the height of the document can be ignored, there is no need to press the document against the stopper 5 and measure the height with the distance measuring plate 4. Further, since the height can be ignored, distortion correction according to the height of the read image is not performed (OFF), so that even if the document is placed in an inclined position, there is no problem if the original is read as it is. So, if the seat mode is selected,
Immediately, the process proceeds to step # 4, where the user is notified that printing is possible, and printing is enabled.

When the book mode is selected (# 1)
YES), the outputs of both photosensors 11 are checked (# 2, # 3). At least one photo sensor 11 is ON
If the document is not displayed (the document is not detected) (NO in # 2), it is determined that the document is not placed yet, and a desired message (for example, “Please place book with stopper”) is displayed. (# 5). Of the photo sensor 11,
When only one sensor is ON (YE in # 2)
S, NO in # 3), as shown in FIG. 4B, it is determined that the book is placed at an angle, and a desired message (for example,
"The book is tilted" is displayed (# 6).
When both photosensors 11 are turned on (YE in # 3)
S), it is determined that the book is placed correctly, the user is notified that printing is possible, and printing is enabled (# 4).

As a method of notifying that printing is possible, a desired message is displayed on a display, and a “Ready” LE provided for the start key 8 is provided.
Or switch D from red to blue. The printing operation is prohibited even if the start key 8 is pressed until printing is possible. Further, as another method, the illumination by the lamp unit 3 is turned off until printing becomes possible, and the illumination is half-lit when printing becomes possible, thereby saving energy.

The photo sensor 11 referred to in this embodiment is:
It is generally called a reflection type photo sensor, and is composed of an infrared LED and a phototransistor to eliminate the influence of visible light, and the light emitted from the infrared LED hits a reflecting object and is reflected. Light is received by a phototransistor to determine the presence or absence of a reflective object.

In this apparatus, before starting the pre-scan operation, the output of the photo sensor 11 checks whether the original is properly placed, and only when it is determined that the original is correctly placed, the pre-scan operation is started. As a result, it is possible to prevent the error from being interrupted due to the inability to measure the distance after the pre-scan operation, as in the past,
There is no waste of time. Note that the present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, a detection unit including a photosensor or a detection switch may be continuously disposed in parallel with the stopper 5, and the appropriateness may be determined by checking the output of the detection unit to determine how the document is placed.

[0019]

As described above, according to the first aspect of the present invention,
Since it is detected before the start of the original reading operation whether or not the original is placed at the correct position on the platen, it is possible to prevent an error interruption during the reading operation beforehand. Operation and time are not wasted. According to the second aspect of the present invention, it is possible to accurately detect whether or not the original is correctly placed without tilting with respect to the stopper by the sensors or switches provided at the left and right target positions on the original table. The effect of is obtained.

[Brief description of the drawings]

FIG. 1 is an external view of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of the document table of the present apparatus as viewed from directly above.

FIG. 3 is a diagram illustrating an arrangement configuration of a photosensor.

FIG. 4A is a diagram illustrating a state where a document is correctly placed on a platen, and FIG. 4B is a diagram illustrating a state where the document is inclined and placed on a platen.

FIG. 5 is a flowchart illustrating an operation of detecting a placement state of a document in the apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 platen 2 scanner unit (reading means) 5 stopper 7 control unit (warning means) 11 photo sensor (detection means)

Claims (2)

[Claims] 1. An image reading apparatus for reading an original such as a book facing upward and placed on a platen, wherein the reading unit reads the original placed on the platen and outputs image data. A stopper provided on one side of the document table and serving as a reference for positioning a document; detecting means provided near the stopper to detect whether the document is placed at a correct position; and a detection signal by the detecting means And a warning means for issuing a warning when it is determined that the document is not placed at a correct position based on the image reading device. 2. An image reading apparatus according to claim 1, wherein said detecting means is a sensor or a switch provided at least at left and right target positions on a document table.