JP2002199190A - Image reader and method for detecting abnormality - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To achieve a maximum reading speed even when an automatic document feeding means is used, and to notify a user of deterioration of a member which is a factor of deteriorating image quality to always provide an optimum image. And an image reading device capable of acquiring the image. An automatic document feeder, an image sensor for reading an image on a document, and a first white plate as a reference for reading an image without using the automatic document feeder as a document image reading reference. Storage means for storing, as a reference value, a second white plate 201 used as a reference when reading using the automatic document feeder, and an output signal level obtained when the first white plate 116 is read by the image sensor When,
By comparing the output signal level when the second white plate 201 is read by the image sensor with the reference value stored in the storage means, the second white plate 201 or the vicinity of the image reading unit is compared. Detecting means for detecting an abnormality of the transmission member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image reading apparatus and an abnormality detecting method.

[0002]

2. Description of the Related Art Conventionally, an image reading apparatus detects a white level reference value in order to set an absolute value of a white level of image data. In this method, a white reference plate is provided outside the image area in the image sub-scanning direction, and a correction coefficient is calculated using the read value of the image sensor on the white reference plate as white level reference data. On the other hand, when using the automatic document feeder, the image reading section is once moved to the position of the white reference plate, the white level is detected, the correction coefficient is calculated, and then the image is read to the reading position by the automatic document feeder. It is customary to move parts.

[0003]

However, when the automatic document feeder is used as described above, the white level detection is one.
In order to perform the operation for each page, the image reading unit is moved for each page. This moving time has been a problem of measures to reduce the time for reading the original.

In addition, when the automatic document feeding means is used, the aging of the white plate and the permeable member which transmits the illumination and reflected light are stained or scratched by paper rubbing or the like, so that when a large number of documents are used. In some cases, accurate reading of an image cannot be performed due to the contamination. Further, there is no method for detecting the degree of dirt or scratches on the transmission member.

The present invention has been made in view of the above circumstances, and achieves the maximum reading speed even when an automatic document feeder is used, and reduces the deterioration of members which is a factor of deteriorating image quality. An object of the present invention is to provide an image reading apparatus and an image reading method that can always obtain an optimum image by notifying a user.

[0006]

The present invention can solve the above-mentioned problems by providing the following constitution.

(1) Automatic document feeding means, document illuminating means for irradiating light to a document, and reading an image on the document by receiving reflected light from the document illuminated by the document illuminating means. An image sensor, a first white plate as a reference when reading an image without using the automatic document feeder as a reference for reading an original image, and a second white plate as a reference when reading using the automatic document feeder as a reference A white plate, storage means for storing an output signal level when the first white plate is read by the image sensor as a reference value, and an output signal level when the second white plate is read by the image sensor And detecting means for detecting an abnormality of the transmission member near the second white plate or the image reading unit by comparing the reference value stored in the storage means,
An image reading apparatus comprising:

(2) The image reading apparatus according to the above (1), wherein the abnormality is caused by dirt or aging.

(3) Automatic document feeding means, document illuminating means for illuminating the document with light, and reading an image on the document by receiving reflected light from the document illuminated by the document illuminating means. An image sensor, a first white plate as a reference when reading an image without using the automatic document feeder as a reference for reading an original image, and a second white plate as a reference when reading using the automatic document feeder as a reference Storing an output signal level when the first white plate is read by the image sensor as a reference value, and a second white plate. Comparing the output signal level when the plate is read by the image sensor with the image sensor; and detecting an abnormality in the second white plate or the transmission member near the image reading unit based on the comparison result. Abnormality detection method characterized by comprising a-up.

(4) The abnormality detecting method according to the above (3), wherein the abnormality is caused by dirt or aging.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 is a side sectional view showing a schematic configuration of an image reading apparatus according to the present invention, FIG. 2 is a side sectional explanatory view showing a control situation in a first embodiment, and FIG. 3 is a second embodiment. FIG. 5 is an explanatory side sectional view showing a control situation in an example.

(First Embodiment) FIG. 1 is a side sectional view showing a schematic configuration of an image reading apparatus according to the present invention.

In FIG. 1, reference numeral 101 denotes a document; 102, a transparent document table using glass or the like for setting the document 101; 103, a light source for irradiating the document 101;
4 is a reflection mirror, 105 is a condenser lens, 106 is a photoelectric conversion circuit for converting received light into an electric signal corresponding to the intensity, and 107 generates image data from the electric signal output from the photoelectric conversion circuit 106. Is an optical unit composed of a light source 103, a reflecting mirror 104, a condenser lens 105, and a photoelectric conversion circuit 106.
01 is an optical unit drive motor for moving in the sub-scanning direction, 110 is a home position sensor for detecting that the optical unit 108 is at a position (home position) where image reading can be started, and 111 is a plurality of originals. ADF (Auto Documenten) which is an automatic document feeding mechanism for automatically feeding a document when reading continuously.
tFeeder), 112 is an ADF drive motor for carrying the document 101 set on the ADF, 113 is a document presence / absence detection sensor for detecting the presence / absence of a document set on the ADF, and 114 is a reading operation by the ADF. When performing the scanning, a top sensor for detecting the leading edge and the trailing edge of the document being conveyed, and determining whether there is the document being read,
Reference numeral 15 denotes a controller for controlling the entire image reading apparatus including the ADF 111.

Upon receiving an image reading start command sent from a host computer (not shown), the controller 115 in the image reading apparatus determines that the optical unit 108 is at a predetermined reading operation start position (home position). After confirmation by the position sensor 110, a white level is detected by the first white plate 116 outside the image area in the sub-scanning direction of the image, and a correction coefficient is calculated. If the optical unit 108 is not at a predetermined position, the controller 115
Drives the optical unit drive motor 109 to move the optical unit 108 and set it at a predetermined position.

After calculating the white level correction coefficient, an image reading operation is started. Document 10 set on platen 102
1 is irradiated with light from a light source 103, and the light reflected by the original 101 passes through a reflecting mirror 104 and passes through a condenser lens 10.
After being imaged at 5, the light enters the photoelectric conversion circuit 106. The light incident on the photoelectric conversion circuit 106 is converted into an electric signal according to the intensity of the light, and is output to the image data generation unit 107. The image data generation unit 107 generates image data corresponding to one line in the main scanning direction of the document 101 based on the electric signal. The controller unit 115 drives the optical unit drive motor 109 simultaneously with the start of the reading operation to generate image data for each line of the original 101 in the main scanning direction while moving the optical unit 108 at a constant speed in the sub-scanning direction. The image reading operation of the entire document 101 ends.

The image data generated by the image data generator 107 is sequentially transmitted to the host computer via the controller 115.

When reading a plurality of originals continuously using the ADF 111, the controller 115 stops the optical unit 108 at a predetermined position using the optical unit drive motor 109, and then drives the ADF drive motor 112. The document 101 set on the ADF 111 is transported one by one at a constant speed.

The original 101 passes over the optical unit 108 stopped at a predetermined position and is discharged to a predetermined discharge port. The controller unit 115 detects whether the top sensor 114 installed on the conveyance path of the original 101
When the leading edge of the sheet is detected, the reading operation of the optical unit 108 is started at a predetermined timing. Optical unit 10
Reference numeral 8 performs a predetermined image reading operation when the document 101 passes, and generates image data for one document. Manuscript 101
When the top sensor 114 detects the trailing edge of the sheet, the controller 115 determines that reading of one document has been completed, and drives the ADF drive motor 112 at a predetermined timing to convey the next document.

The above-described reading operation is performed by the document presence detection sensor 1
The image reading operation of a plurality of documents is automatically performed by repeating the process until the document 101 is detected to be exhausted at 13.

FIG. 2 is a schematic explanatory diagram showing a control situation at the time of detecting a white level when the ADF 111 is used.

In FIG. 2, the controller unit 115 uses the optical unit driving motor 109 to control the optical unit 10.
8 is stopped at a predetermined image reading position, a white level is detected by the second white plate 201, and a correction coefficient is calculated. Thereafter, the original 101 passes through the transport path 202 and passes through the optical unit 10.
Reference numeral 8 denotes the original 1 via the glass plate 102 and the transparent member 203.
The image data is read from 01. Then, the white level is detected and the correction coefficient is calculated again until the next original arrives.

(Second Embodiment) A control example of a second embodiment of the present invention will be described with reference to FIG. When reading a document using the ADF 111 as in the first embodiment, when the controller unit 115 in the image reading apparatus receives an image reading start command, the optical unit 108 moves to the position of the first white plate 116.

Then, the white level is detected, the correction coefficient is calculated, and the value of the white level of the first white plate 116 is stored in the RAM in the controller 115. Thereafter, the controller unit 115 controls the optical unit drive motor 109.
The optical unit 108 is stopped at a predetermined image reading position by using, and the white level is detected by the second white plate 201. Then, the value of the white level of the first white plate 116 and the white level of the second white plate 201 are compared, and if the difference is larger than the reference value, the second white plate or the transparent member 203 becomes dirty. Or that it has changed over time, and informs the operator that replacement is required. If the value is larger than the reference value, the correction coefficient is calculated, and the document is read continuously as in the first embodiment.

Although the first and second embodiments have been described with reference to an image reading apparatus connected to a host computer, an apparatus having an image forming unit and an image reading unit called a multi-function printer has recently been described. Has been developed, and similar control is possible for the image reading means of such an apparatus.

[0026]

As described above, according to the invention of the present application, it is possible to detect an abnormality of a white plate or a transmission member in an image reading apparatus provided with an automatic document feeder and notify an operator. It has the effect of being able to do it.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a schematic configuration of an image reading apparatus according to the present invention.

FIG. 2 is an explanatory side sectional view showing a control situation in the first embodiment;

FIG. 3 is an explanatory side sectional view showing a control situation in a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 101 document 102 transparent document table 103 light source 104 reflecting mirror 105 condensing lens 106 photoelectric conversion circuit 107 image data generating unit 108 optical unit 109 optical unit driving motor 110 home position sensor 111 automatic document feeding mechanism (ADF) 112 ADF driving motor 113 Document presence / absence detection sensor 114 Top sensor 115 Controller unit 116 First white plate 201 Second white plate

Claims (4)

[Claims] An image reading means for reading an image on a document by receiving reflected light from the document illuminated by the document illuminating means; A sensor, a first white plate as a reference when reading an image without using the automatic document feeder as a reference for reading an original image, and a second white plate as a reference when reading using the automatic document feeder. A white plate, storage means for storing an output signal level when the first white plate is read by the image sensor as a reference value, and an output signal level when the second white plate is read by the image sensor. Detecting means for detecting an abnormality of the transmission member near the second white plate or the image reading unit by comparing the reference value stored in the storage means. Image reading device. 2. The image reading apparatus according to claim 1, wherein
The image reading apparatus according to claim 1, wherein the abnormality is caused by dirt or aging. 3. An image reading apparatus for reading an image on an original by receiving a reflected light from the original illuminated by the original illuminating means, an automatic original feeding means, an original illuminating means for irradiating the original with light, and an original illuminating means. A sensor, a first white plate as a reference when reading an image without using the automatic document feeder as a reference for reading an original image, and a second white plate as a reference when reading using the automatic document feeder. A white plate, and a method of detecting an abnormality in the image reading device, comprising: storing an output signal level when the first white plate is read by the image sensor as a reference value; and the second white plate. Comparing an output signal level when the image is read by the image sensor, and detecting an abnormality in the transmission member near the second white plate or the image reading unit based on the comparison result. Abnormality detection method characterized by including and. 4. The abnormality detection method according to claim 3,
The abnormality detection method is characterized in that the abnormality is caused by dirt or aging.