JPH0440058A - Original reader - Google Patents

Abstract

PURPOSE:To exactly correct the read signal of original information by feeding a blank sheet to an adhering sensor prior to the reading of the original information, and detecting the data of a blank output on the blank sheet with the adhering sensor. CONSTITUTION:Prior to the reading of the original information, a sheet supplying means 7 feeds a blank sheet 5 to an adhering sensor 2, and the adhering sensor 2 detects the blank output on the blank sheet. Therefore, the dispersion data of a blank output waveform can be calculated. Thus, shading correction is attained and since the blank sheet 5 is moved from the adhering sensor 5 by being taken-up with the sheet supplying means 7 in the case of reading the original information, the blank sheet 5 is prevented from being stained by an original.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a document reading device that reads document information from a moving document using a contact sensor, and particularly relates to signal detection for shading correction in this document reading device.

(Prior Art) In the above-mentioned conventional document reading device, those that perform shading correction etc. read a dedicated sheet in advance on the production line, obtain white waveform variation data based on the white waveform output at this time, and The data was written into a memory element such as an EPROM, and shading correction was performed based on this variation data.

(Problems to be Solved by the Invention) In the conventional apparatus described above, if a phenomenon occurs such as a drop in both ends of the white waveform output due to changes over time in the light source that illuminates the original, even if shading correction is performed, the Since the output waveform has dips at both ends, there is a problem in that a flat output waveform cannot always be obtained.

Furthermore, even if the surface of the platen roller installed opposite to the contact sensor is set to a white background and the white output of this white background is read to perform shading correction, the white background may become dirty due to dirt or dust from the original, and the accurate signal cannot be obtained. There is a problem that it cannot be detected.

An object of the present invention is to provide a document reading device that can accurately and reliably obtain white output data.

(Means for Solving the Problems) In order to achieve the above object, a first means of the present invention includes a platen roller and a contact sensor that is in close contact with the platen roller via the document and reads document information from the moving document. A document reading device comprising: a sheet feeding means for feeding a white background sheet to a contact sensor and winding up the white background sheet before reading document information, and detecting a white output of the white background sheet by the contact sensor. It is characterized by being configured to do so.

A second means of the present invention is a document reading device including a platen roller and a contact sensor that is in close contact with the platen roller via the document and reads document information from the moving document, and before reading the document information, The present invention is characterized in that it includes an electromagnetic device that feeds a white background sheet to a contact sensor and returns the white background sheet, and is configured such that the contact sensor detects a white output of the white background sheet.

(Function) According to the first means described above, before reading the document information, the sheet supply means feeds the blank sheet to the contact sensor, and the contact sensor detects the white output of the blank sheet, thereby increasing the white output. Waveform variation data can be obtained, and shading correction can be performed based on this data. Also, when reading document information, the blank sheet is taken up by the sheet supply means and moved from the contact sensor, so depending on the document, the blank sheet may be will not be defiled.

According to the second means, before reading the document information, the electromagnetic device sends the blank sheet to the contact sensor, and the first
The white output for shading correction can be detected in the same way as the means, and furthermore, since the blank sheet is returned to a predetermined position from the contact sensor by the electromagnetic device when reading document information, the blank sheet is not soiled by the document.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of the first embodiment of the present invention, and FIG. 2 is a block diagram of the operating state of the first embodiment. 1 is a platen roller;
Reference numeral 2 denotes a close contact sensor that is installed opposite to the platen roller 1 so as to be in close contact with the document through the document, and reads document information from the moving document; 3 is a document guide plate; and 4 is a pair of sensors installed above the document guide plate 3. 5 is a flexible white sheet that moves between the sheet guide plates 4; 6 is a brush body provided at one end of the white sheet 5; 7 is a brush body connected to the other end of the white sheet 5; This is an operating shaft that is a sheet feeding means for feeding and winding up the sheet 5.

In FIG. 1, before reading the document information, rotate the operating shaft 7 clockwise to move the blank sheet 5 onto the sheet guide plate 4.
While guiding the paper, feed it between the platen roller 1 and the contact sensor 2. Here, move the platen roller 1 in the document advancing direction (
clockwise) to further move the blank sheet 5 to the left.

As shown in FIG. 2, when the white background sheet 5 has moved sufficiently,
The contact sensor 2 is turned on to detect the white output from the white background sheet 5 held between the platen roller 1 and the contact sensor 2, and based on the white waveform output from the white background sheet 5, the white waveform variation data is calculated. A data processing section (not shown) obtains the data, and shading correction is performed based on the obtained white waveform variation data.

After detecting the variation data, the platen roller 1 is rotated counterclockwise and the operation shaft 7 is rotated counterclockwise to wind up the blank sheet 5. When reading document information, the blank sheet 5 is rotated counterclockwise. The sheet is retracted from between the roller 1 and the contact sensor 2 to the sheet guide plate 4, as shown in FIG.

When the white background sheet 5 moves over the contact sensor 2, dust and dirt on the contact sensor 2 can be removed by the brush body 6 of the white background sheet 5, thereby eliminating the influence of dust and dirt during shading correction. .

When reading the document information, since there is no blank sheet 5 between the platen roller 1 and the contact sensor 2, the moving document is held between the platen roller 1 and the contact sensor 2, and the document information is detected by the contact sensor 2. is read.

Further, the blank sheet 5 is not soiled by the original.

FIG. 3 is a block diagram of a second embodiment of the present invention, and FIG. 4 is a block diagram of the second embodiment in an operating state, in which 11 is a platen roller, and 12 is a platen roller that is in close contact with the platen roller 11 through the document. 13 is a document guide plate, 14 is a sheet guide plate installed below the document guide plate 13, and 15 is a sensor that moves on the sheet guide plate 14. A white background sheet, 16 a brush body provided at one end of the white background sheet 15, 17 an electromagnetic device equipped with an operating rod 18 connected to the other end of the white background sheet 15, and 19 an electromagnetic device that pulls the operating rod 18 in the direction of the contact sensor 12; The electromagnetic device 17 is a tension spring that pulls the operating rod 18 in the on state and pulls the operating rod 18 in the off state.
It is a composition that releases the attraction of

In FIG. 3, before reading the document information, the electromagnetic device 1
Turn off 7. Then, the operating rod 18 is pulled leftward by the tension spring 19, and the blank sheet 15 is guided by the sheet guide plate 14 and sent out between the platen roller 11 and the contact sensor 12. Here, the platen roller 11 is driven in the document advancing direction (clockwise), and the white background sheet 15 is further moved to the left.

As shown in FIG. 4, when the white background sheet 15 has moved sufficiently, the contact sensor 12 is turned on, and the white output from the white background sheet 15 held between the platen roller 11 and the contact sensor 12 is detected. Based on the white waveform output from 15, white waveform variation data is obtained by a data processing section (not shown), and shading correction is performed based on the obtained white waveform variation data.

After detecting the variation data, the platen roller 11 is rotated counterclockwise, the electromagnetic device 17 is turned on, and the operating rod 18 is pulled to the right against the elastic force of the tension spring 19. Move the sheet 15 to the right,
When reading document information, the blank sheet 15 is inserted between the platen roller 1 and the contact sensor 12, as shown in FIG.
It is evacuated to the sheet guide plate 14 portion.

Also in the second embodiment, as in the first embodiment, when the white background sheet 15 moves over the contact sensor 12, the brush body 16 of the white background sheet 15 removes dust and dirt on the contact sensor 12. This makes it possible to eliminate the effects of dust and dirt during shading correction.

When reading the document information, since there is no blank sheet 15 between the platen roller 11 and the contact sensor 12, the moving document is
2, and the contact sensor 12 reads the document information. Further, the blank sheet 15 is not soiled by the original.

As mentioned above, the first. According to the second embodiment, a dedicated white background sheet is used for detecting white output data, and the white background sheet is not soiled by originals, and the white output data is accurate even in response to changes in the light source over time. Moreover, it is possible to reliably detect, correct the read signal appropriately, and suppress deterioration of image quality.

(Effects of the Invention) The first aspect of the present invention. According to the second means, before reading the document information, the white background sheet can be sent to the contact sensor and the white output data on the white background sheet can be detected by the contact sensor,
Furthermore, since there is no contact between the blank sheet and the original, white output data can be detected accurately and reliably over a long period of time.
It is possible to provide a document reading device in which a reading signal of document information is corrected appropriately.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a first embodiment of a document reading device of the present invention;
FIG. 2 is a configuration diagram of the operating state of the first embodiment. FIG. 3 is a block diagram of a second embodiment of the present invention, and FIG. 4 is a block diagram of the operating state of the second embodiment. 1.11...Platen roller, 2,12...Adhesion sensor, 5,15...White background sheet, 6.16...
Brush body, 7... Sheet supply means, 17... Electromagnetic device.

Claims (2)

[Claims] (1) In a document reading device equipped with a platen roller and a contact sensor that is in close contact with the platen roller through the document and reads document information from the moving document, the contact sensor of the blank sheet is sent to the contact sensor before reading the document information. sending out,
and a sheet supplying means for winding up a blank sheet, and the contact sensor is configured to detect white output on the blank sheet. (2) In a document reading device equipped with a platen roller and a contact sensor that is in close contact with the platen roller through the document and reads document information from the moving document, the contact sensor of the blank sheet is sent to the contact sensor before reading the document information. sending out,
and an electromagnetic device for returning a white background sheet, and the document reading device is configured such that the contact sensor detects a white output on the white background sheet.