JP2665940B2 - Image reading device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus that converts an image of a document obtained by irradiating light into an electric signal, and particularly relates to a light distribution difference of an optical system and a lighting member. The present invention relates to an image reading apparatus having a white layer holding member for correcting a variation in light amount of the image reading device.

<Prior Art> Conventionally, in an apparatus such as a copying machine, a facsimile, or the like, reflected light obtained by irradiating light from a lighting member to a white reference plate constituting a white member is formed on a photoelectric conversion member. After converting to a voltage level to obtain white image data, the image data when the image of the document was read was corrected based on the data.

Therefore, various optical factors (for example, the light distribution difference of the lighting member,
Fluctuations in light amount due to the cosine fourth-law characteristic of the imaging level) are absorbed to realize a faithful read reproducibility of the original image.

The white reference plate used was of the form described below.

(1) A member for holding the lower surface of the original placing plate (the surface opposite to the original placing surface) is brought into contact with the lower surface of the original placing plate, and white paper is attached to the lower surface of the holding member, or white printing or white printing is performed. Painted.

(2) White paper is directly adhered to the lower surface of the document mounting plate, or white paper is printed or painted.

(3) The mounting plate is fixed to the upper surface (original mounting surface) of the original mounting plate, and a fixing member for defining a mounting position of the original is provided in contact with the mounting plate. A white paper is pasted on the contact surface of, or white printed or painted.

(4) White paper is directly adhered to the upper surface of the document mounting plate, or white paper is printed or painted.

<Problems to be solved by the invention> However, when the white reference plate in the above-mentioned conventional example is used, there are the following problems.

That is, in the above-described conventional examples (1) and (2), since the white portion has a height difference from the document placing surface, the irradiation distribution, the image formation state on the photoelectric conversion element, and the like fluctuate, and accurate correction is performed. May not be possible.

Further, in the conventional example (3), the original is placed on the placing plate and guided against the fixing member, or dust or cleaning liquid enters the white portion when cleaning the apparatus plate. In some cases, the performance as a white reference plate may be impaired.

Further, in the conventional example (4), there is a problem that a material having a high transmittance is required as a material of the document placing plate in order to prevent a decrease in the reflectance, and the cost tends to be high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an image reading apparatus having a white reference member for correcting a light distribution difference of an optical system, a variation in light amount of an illumination member, and the like.

<Means for Solving the Problems> A configuration according to the present invention for solving the above problems includes a transparent document placing plate, a white reference member provided near an end of the document placing plate on the document placing surface side. A light source that moves while irradiating light from the side opposite to the original placing surface of the original placing plate, a photoelectric conversion member that receives reflected light from the original, and read data when reading the white reference member. And a correction unit that corrects the original reading data based on the original reading data, wherein the white reference member is mounted on the original mounting via an adhesive layer except for a region elongated in a direction perpendicular to the moving direction of the light source. The correction means is attached to a plate, and the correction means corrects the original read data based on the read data of the white reference member in an area not via the adhesive layer.

<Operation> In the above configuration, since the white reference member is attached to the document placing plate via the adhesive layer except for a region elongated in a direction perpendicular to the moving direction of the light source, the white reference member is moved to the elongated region. Dust and cleaning liquid can be prevented from entering.

Further, since the correction of the read data is performed based on the read data of the white reference member in the area not passing through the adhesive layer, the white reference member is further affected by the adhesive layer without being affected by the adhesive layer. Because it can be configured with height,
Accurate light amount correction and shading correction can be performed.

Embodiment An embodiment of an image reading apparatus to which the present invention is applied will be described with reference to the drawings.

FIG. 1 is an explanatory sectional view showing a main part of an image reading apparatus to which the present invention is applied, and FIG. 2 is an explanatory view showing an entire configuration of the image reading apparatus.

First, a schematic configuration of an image reading apparatus to which the present invention is applied will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes an image reading apparatus, and a document mounting plate 2 made of a transparent glass plate having a square shape is fixed to a central portion of the upper surface of the image reading device. The outer periphery 3 of a white layer holding portion, which is a white reference member to be described later and serves as a guide when a document is placed, is attached to the four peripheral edges of the document placing plate 2. 4 covers and fixes the periphery of the white layer holding member 3 and the device 1
A document pressing plate 5 for pressing and fixing a document is attached to an upper edge of the upper cover 4 adjacent to the white layer holding member 3 so as to be openable and closable. .

Next, a main part of an image reading apparatus to which the present invention is applied will be described with reference to FIG. FIG. 1 shows A in FIG.
It is sectional explanatory drawing of -A.

First, the configuration of the white layer holding member 3 will be described.

The white layer holding member 3 has a printed layer 3b such as a marking or a scale indicating the size of the document formed on the upper surface of a sheet-shaped base material 3a. The upper surface of the printing layer 3b is covered with a thin film-like laminate 3c in order to prevent printing defects such as the above markings. Further, a white reference plate having a white printed layer formed on the lower surface of the base material 3a for reflecting the irradiated light is formed.
3d is affixed.

Next, a seal member that joins the white layer holding member 3 and the document placing plate 2 will be described.

The white layer holding member 3 configured as described above has its lower surface of the white reference plate 3d adhered to the upper surface of the document placing plate 2 through double-sided adhesive tapes 6a and 6b having a thickness of about 0.1 mm or less. I have.

Accordingly, the double-sided adhesive tapes 6a and 6b form the white area 6c and the non-white areas 6a and 6b where the white printed layer can be read on the white reference plate 3d, and the white layer holding member 3 and the document placing plate 2 And glue them together.

When the original 7 is placed on the original placing plate 2, the original reading surface and the reading surface of the white reference plate 3d are so thin that the thickness of the double-sided adhesive tapes 6a and 6b is negligible as described above. Therefore, it can be regarded that the document is at substantially the same height as the upper surface of the document placing plate 2.

Next, a description will be given of the image reading system. Reference numeral 8 denotes an illumination member such as a fluorescent lamp serving as a light source, which scans in the direction of arrow A in the drawing to scan the illumination member 8 as is clear from FIGS. The white reference plate 3d of the elongated white area 6c or the original 7 in a direction perpendicular to the direction is illuminated. The light emitted from the illumination member 8 is in the white area.
6c is reflected by the white reference plate 3d or the original 7,
The reflected light is imaged on the photoelectric conversion member 9 via a mirror, a lens (not shown), or the like, and an electric signal corresponding to the amount of the reflected light can be obtained.

Further, in order to obtain a more appropriate white reference signal in the image reading apparatus 1 configured as described above, it is necessary to illuminate the substantially central portion of the white area 6c when the illumination member 8 scans.
It is necessary to perform positioning so that light is irradiated.

As means for positioning the irradiation member 8 for this purpose,
An illumination member 8 for scanning a position sensor and an actuator (not shown) of the sensor is provided on a fixed side of the document placing plate 2 and the like, and the position of the illumination member 8 for scanning is determined by a detection signal of the position sensor. Can be controlled. In addition, a marking is provided along the sub-scanning direction substantially in the center of the white reference plate 3d in the white region 6c, and an output signal obtained by forming an image of the reflected light irradiated from the irradiation member 8 on the photoelectric conversion member 9 is detected. Thus, the position of the irradiation member 8 can be controlled.

Accordingly, in the correcting means for correcting the amount of light emitted from the position-controlled illumination member 8, the reading surface of the document 7 and the reading surface of the white reference plate 3 d are higher than the upper surface of the document placing plate 2. Since there is almost no difference, the white reference plate in the white area 6c
Based on a white reference signal obtained by imaging the light reflected from 3d on the photoelectric conversion member 9, shading correction or light amount correction performed by multiplying the image signal of the original 7 by the reciprocal of the white reference signal is performed. Can be performed with precision.

Further, since the white reference plate 3d is adhered to the original placing plate 2 by the double-sided adhesive tapes 6a and 6b and the white region 6c is shielded from the outside, dust, cleaning liquid and the like enter the white reference plate 3d. Can be prevented, and the performance as a white layer can be maintained.

In the above embodiment, the white reference plate 3d is adhered to the original placing plate 2 with the double-sided adhesive tapes 6a and 6b, but may be adhered with an adhesive instead of the double-sided adhesive tapes 6a and 6b. It is possible.

<Other Embodiments> Next, another embodiment of the white layer holding member in the above embodiment will be described with reference to FIGS. 3 and 4. FIG.

In FIG. 3, reference numeral 10 denotes a white layer holding member, on which a printed layer 10b such as a marking or a scale indicating the size of a document is formed on the upper surface (left side in the drawing) of a sheet-like substrate 10a. . The upper surface of the printing layer 10b is a thin film-like laminate layer to prevent the above-mentioned printing loss such as marking.
Covered in 10c. A white reference plate 10d on which a white print layer capable of obtaining a white reference signal by reflecting light emitted from the illumination member 8 is attached to the lower surface (the right side in the drawing) of the base material 10a. ing. An adhesive 10e is applied as a seal member to the lower surface of the white reference plate 10d by printing.

Accordingly, the adhesive 10e forms a white area 10f and a non-white area 10e where the white print layer can be read on the white reference plate 10d, and separates the white layer holding member 10 and the document placing plate 2 from each other. Is glued.

When the white layer holding member 10 configured as described above is used, when the white layer holding member 10 is arranged by sticking the adhesive 10e on the original placing plate 2, the adhesive 10e Since it is formed by printing, the distance 10e 'between the original placing surface and the white area 10f formed by the printing layer of the adhesive 10e is 1 mm.
The following configuration is possible, so that the scanning distance of the illumination member 8 can be reduced and the size of the apparatus can be reduced. Further, since the pressure-sensitive adhesive 10e is formed by printing, it can be configured to easily correspond to a complicated pattern, and since the white region 10f can be formed by press blanking, the manufacturing cost can be reduced.

FIG. 4 shows a structure in which a white layer holding member and an upper cover which covers and fixes the periphery of the white layer holding member and constitutes the exterior of the apparatus are integrally formed.

In the figure, reference numeral 11 denotes an upper cover,
Are arranged on the four peripheral edges of the upper surface of the. A concave portion 11a is formed in a surface of the upper cover 11 on the document placing plate 2.
A white printed layer 11d is formed in the recess 11a, and an adhesive 11e is applied to the flat portions 11b and 11c on both sides of the recess 11a and adheres to the upper surface of the document placing plate 2. It is configured as follows.

Therefore, the upper cover 11 is bonded to the upper surface of the document placing plate 2 by forming a white area with the recess 11a and a non-white area with the flat portions 11b and 11c.

When using the upper cover 11 configured as described above,
Since the upper cover 11 also functions as a white layer holding member, it is possible to reduce parts costs and assembly costs.

<Effect of the Invention> As described above, according to the present invention, since the white reference member is attached to the document placing plate via the adhesive layer except for the region elongated in the direction perpendicular to the moving direction of the light source, It is possible to prevent dust, cleaning liquid and the like from entering the area. Then, the correction of the read data is performed based on the read data of the white reference member in the area not passing through the adhesive layer,
Accurate light amount correction can be performed without being affected by not only dust but also the adhesive layer.

Further, since the white reference member and the document reading surface can be configured with substantially the same height, accurate light amount correction and shading correction can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a main part of an image reading apparatus to which the present invention is applied, FIG. 2 is an explanatory view showing the overall configuration of the image reading apparatus, and FIGS. 3 and 4 are white layer holding members. It is explanatory drawing of another example of. 1 is an image reading device, 2 is a document placing plate, 3 and 10 are white layer holding members, 3a and 10a are base materials, 3b and 10b are printing layers, 3c and 10c are laminate layers, and 3d and 10d are white reference plates. , 4 and 11 are upper covers, 5 is a document pressing plate, 6a and 6b are double-sided tapes, 7 is a document, 8 is an irradiation member, 9 is a photoelectric conversion member, 10e and 11e are adhesives, 11a is a recess,
11d is a white print layer.

Claims (1)

(57) [Claims] A transparent original placing plate, a white reference member provided near an end of the original placing plate on a side of the original placing surface, and a document placing surface of the original placing plate which is opposite to the original placing surface. An image reading apparatus comprising: a light source that moves while irradiating light; a photoelectric conversion member that receives reflected light from a document; and a correction unit that corrects document read data based on read data when a white reference member is read. In the above, the white reference member is attached to the document placing plate via an adhesive layer, except for an elongated region in a direction perpendicular to the moving direction of the light source, and the correction unit applies the adhesive layer An image reading apparatus that corrects document read data based on read data of a white reference member in an area not interposed.