JP2884592B2 - Image reading device - Google Patents

Description

The present invention relates to a configuration of an image reading device.

2. Description of the Related Art A typical document reading apparatus for inputting a document such as a character or a photograph into a computer is a so-called flatbed image scanner. This generally has an optical head for reading one line of a document and a mechanism for moving the optical head in a direction perpendicular to the reading line. The optical head reads the entire document while moving along the document. FIG. 2 shows an example of the basic configuration of a flatbed image scanner. Here, the optical head 1
Has a light source that illuminates the original, a one-dimensional sensor that converts the image of the original into an electric signal, and a lens that forms the reflected light of the original on the one-dimensional sensor. By sequentially obtaining the output from the sensor while moving the head in the sub-scanning direction, a two-dimensional image can be obtained as an electric signal. The moving direction of the optical head 1 is regulated by the sliding rail A7 and the sliding rail B8, and the optical head 1 is configured to move accurately in the sub-scanning direction along these rails.

[Problems to be Solved by the Invention] However, in the configuration shown in FIG. 2, the quality of the read image largely depends on the accuracy of the movement of the optical head 1 in the sub-scanning direction. It is necessary to ensure high precision and to prevent the play between the slide rail B8 and the optical head 1 as much as possible. On the other hand, from the necessity of performing higher-precision reading,
As the density of image reading becomes higher and higher, the density of sensors is required to be higher, and the accuracy of movement in the sub-scanning direction is required to be higher with higher resolution of the sensor. There is a problem that it is difficult to suppress the straightness of the corresponding sliding rail B8 and the play with the optical head 1.

In view of the above, in the present invention, the sub-scanning of the optical head 1 aims at realizing accurate reading without requiring high-precision parts for regulating in the sub-scanning direction.

[Means for Solving the Problems] In order to solve the above problems, an image reading apparatus of the present invention reads a document table glass on which a document is placed, and reads an image of a document placed on the document table glass. An image reading apparatus comprising: a one-dimensional sensor having a plurality of pixels for scanning; and a parting plate disposed on a platen glass along a sub-scanning direction for abutting an end surface of the document. The surface on the base glass side has a reference as a form of a boundary line which is substantially white and substantially black and is color-coded along the sub-scanning direction, and based on a pixel position on a one-dimensional sensor for reading the reference, data reading is performed. In this case, the reading start pixel position in the main scanning direction is determined for each reading line in the sub-scanning direction.

An image reading apparatus according to the present invention further includes a platen glass for placing a document, a one-dimensional sensor having a plurality of pixels for reading an image of the document placed on the platen glass, and an end face of the document. And a parting plate disposed on the platen glass along the sub-scanning direction for contacting the platen plate. It has a reference as a form of a boundary line that is substantially black and is color-coded along the sub-scanning direction, and based on a pixel position on the one-dimensional sensor that reads the reference, determines a reading start pixel position in the main scanning direction when reading data. The determination is made for each reading line in the sub-scanning direction.

Further, any of the image reading devices described above,
The reading start pixel position in the main scanning direction at the time of data reading is a position n pixels away from the reference reading pixel position in the main scanning direction.

Embodiment FIG. 1 is a sectional view showing a configuration of one embodiment of the present invention. Here, the parting plate 2 is a member for abutting the end face of the original when placing the original to be read on the original platen glass 3 as a reference. The reference line 4 is printed on the back side of the parting plate 2 in parallel to the moving direction (sub-scanning direction) of the optical head 1 as shown by a dotted line in FIG.
Is configured to have a sufficient length for the reading range of the document and to be able to read the reference line 4. In the conventional reading operation, the reading start position on the sensor array 5 is a fixed point of the sensor bits. In the present invention, the position of the reference line 4 is checked for each line, A position n bits away from the sensor bit corresponding to the reference line 4 is set as a reading start position. When the reading operation is performed while moving in the sub-scanning direction, the reading start position on the sensor array 5 is changed by determining the reading start position in this manner. Is always kept at a constant interval with respect to the reference line 4. Therefore, even if the optical head 1 shifts in the direction in which the sensor rows 5 are arranged (main scanning direction) during the original reading operation, the read image can be obtained with high accuracy without shifting.

The embodiment of the present invention is not limited to the above embodiment. For example, instead of the reference line 4, the back of the parting plate is separately painted as shown in FIG. The present invention can also be configured by a method such as printing on the platen glass 3.

[Effects of the Invention] As described above, according to the present invention, it is possible to improve the accuracy of a read original without restricting the movement direction of the optical head 1 with high accuracy.

Further, as a further effect, the position of the parting plate 2, which is a reference of the position of the original, has conventionally been required to be attached to the optical head 1 with high positional accuracy. At the time of mounting the plate 2, it is possible to obtain a reading accuracy far higher than in the past without performing adjustment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing one configuration example of the present invention. FIG. 2 is a perspective view showing a conventional example. FIG. 3 is an explanatory view showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Optical head 2 ... Parting-off board 4 ... Reference line 5 ... Sensor row

Claims (3)

(57) [Claims] An original platen for placing an original; a one-dimensional sensor having a plurality of pixels for reading an image of the original placed on the original platen glass; And a parting plate disposed on the platen glass along the sub-scanning direction for the platen plate glass side surface of the parting plate, substantially white and substantially black It has a reference as a mode of a boundary line that is color-coded along the sub-scanning direction, and based on a pixel position on the one-dimensional sensor that reads the reference, sets a read start pixel position in the main scanning direction when reading data. An image reading device that determines each reading line in the sub-scanning direction. 2. A document table glass for placing a document, a one-dimensional sensor having a plurality of pixels for reading an image of the document placed on the document table glass, and an end surface of the document in contact with each other. And a parting plate disposed on the platen glass along the sub-scanning direction for reading, the platen glass on the lower surface of the parting plate provided is substantially white and substantially white. A read start pixel in the main scan direction at the time of data reading, based on a pixel position on the one-dimensional sensor that reads black as a boundary line that is color-coded along the sub-scan direction and that reads the reference. An image reading device for determining a position for each reading line in the sub-scanning direction. 3. The reading start pixel position in the main scanning direction at the time of data reading is a position n pixels away from the reference reading pixel position in the main scanning direction. The image reading device according to claim 1.