JP2005295359A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader capable of reading an image by separately setting a read mode matching with the image to the front and rear of a document. <P>SOLUTION: The image reader comprises a read mode setting means for separately setting the read mode to each of the front and rear of the document, and an image processing means for processing the image by reading and scanning each image on the front and rear of the document according to the read mode set by the read mode setting means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus capable of reading a front surface and a back surface of a document in parallel.

The following patent documents propose an image reading apparatus that simultaneously reads the front and back surfaces of a single document. When this image reading apparatus operates a single document and reads both sides thereof, if the time required for encoding the image data on the front side differs from the time required for encoding the image data on the back side, The scanning of the original is performed in accordance with the one that takes time to encode.
JP-A-9-205524

However, in recent years, hardware that performs high-speed encoding has been developed and is commercially available at a low price. Therefore, an apparatus that can read both sides of a single document in different reading modes is desired. Yes. Reading in different reading modes means that if a single document has a photo on its front side, text on the back side, or text on both sides, but the text on the back side is very fine, the scanning mode that matches these images is used. It means that the image is read by setting the front side and the back side.
An object of the present invention is to provide an image reading apparatus capable of reading an image by individually setting the reading mode according to the image on the front surface and the back surface.

In order to solve the above-mentioned problems, according to claim 1 of the present invention, in an image reading apparatus that reads and scans the front and back surfaces of the same document by the first and second scanning means, Reading mode setting means for individually setting the reading mode for each of them, and image processing is performed by reading and scanning each of the front and back images of the document according to the reading mode set by the reading mode setting means. An image reading apparatus including an image processing unit is proposed.
According to a second aspect of the present invention, when the reading scanning speed of the reading mode set for each of the front surface and the back surface of the document is different from each other, the image processing means slows down the reading scanning speed of the reading mode having a higher reading scanning speed. Thus, an image reading apparatus is proposed that is configured to read and scan each of the image on the front side and the image on the back side in accordance with a reading mode in which the reading scanning speed is slower. Therefore, when the fine mode reading mode is set on the front side of the document and the high resolution super fine mode reading mode is set on the back side, the reading scanning speed on the back side is slower than the front side. The scanning speed is adjusted.
According to a third aspect of the present invention, there is further provided an image reading apparatus that further includes a conveying unit that conveys a document, and each of the first and second scanning units is disposed at two positions on the document conveying path of the conveying unit Yes.
According to a fourth aspect of the present invention, each of the first and second scanning units includes an image sensor that reads an original, and the image sensor proposes an image reading device that is of a different type.

According to the first to fourth aspects, since the reading mode can be individually set for each of the front side and the back side of the document, the types of images are different between the front side and the back side, that is, one is a photographic image and the other is a character image. In such a case, reading suitable for the images can be executed.
In particular, when the reading scanning speed of the reading mode set for each of the front surface and the back surface of the document is different from each other, the reading scanning speed of the reading mode having a higher reading scanning speed is decreased, Since the original is read by the scanning means arranged at two places on the original conveying path of the conveying means in accordance with the reading mode having a slower reading scanning speed, the mechanism and the control can be simplified.
In particular, since different types of image sensors are used for the first and second scanning means, the first image sensor is inexpensive at most, and the second image sensor is expensive but small. The combination and apparatus, particularly the automatic document feeding mechanism, can be made compact, and an increase in cost can be suppressed.

  The present invention can be widely applied to a document reading device that reads the front and back surfaces of a document. A facsimile machine, a scanner device, and a so-called multifunction device that combines a copy function will be described in detail below as an example. explain.

FIG. 1 is a block diagram illustrating a basic configuration of a multi-function peripheral M that is an embodiment of an image reading apparatus according to the present invention.
The multi-function device M is configured by an MPU or the like, and stores a control unit 11 that controls each unit of the multi-function device M by software processing, a program memory 12 that stores programs constituting the software, and various data. A data memory 13, a liquid crystal panel, and the like, a display unit 14 for displaying information according to the user's operation and the state of the apparatus, an operation unit 15 for the user to operate, and an image on the surface of the document The first scanner unit 16A for reading the image, the second scanner unit 16B for reading the image on the back side of the document, and the image data read by the first scanner unit 16A or the second scanner unit 16B are stored. Image memory 17, printer unit 18 that prints image data stored in image memory 17 on paper, and modulates the image data and sends it to a telephone line Rutotomoni, network control circuit 20 for controlling the connection between the modem 19 for demodulating a signal received from the telephone line and the telephone line (NCU: Network
Control Unit).

  In the image reading apparatus of the present invention, each of the front side and the back side of the document is read and scanned by the first and second scanning units according to the reading mode individually set for each of the front and back sides of the document. Therefore, the multifunction machine M includes the first scanner unit 16A and the second scanner unit 16B as the first and second scanning units. The operation unit 15 includes a first reading mode setting key (A) 151 as reading mode setting means for individually setting the reading mode for each of the scanner unit 16A and the second scanner unit 16B. And a second reading mode setting key (B) 152.

  That is, the first reading mode setting key (A) 151 is composed of a plurality of setting keys, and the user operates them so that the first scanner unit 16A can make a monochrome suitable for a document with only characters. A mode or halftone mode suitable for a document such as a photo can be set, and the density can be set. The same applies to the second reading mode setting key (B) 152, and the reading mode can be set for the first scanner unit 16B. For any of the reading mode setting keys, in the case of reading for facsimile communication, it is possible to set a reading mode related to resolution, that is, a reading mode such as standard, fine mode, and super fine mode. .

  The scanner unit 16A includes a read image processing circuit 160A that processes a read image and a conveying unit 169, and the scanner unit 16B includes a read image processing circuit 160B that processes the read image. The read image processing circuit 160A and the read image processing circuit 160B function as image processing means that performs image processing by reading and scanning each of the front and back images of the document.

FIG. 2 is a more detailed block for explaining the basic configuration of the read image processing circuit 160A, in which a charge-coupled device (CCD: Charge) constituting a scanning unit is shown.
An analog signal indicating the density of the image of the document read by the coupled device (161A) is converted into a digital signal by an analog / digital (A / D) converter 162A and input to the image correction circuit 163A. In the image correction circuit 163A, processing such as shading correction and edge enhancement is performed, which is not shown, starting with γ correction. The output of the image correction circuit 163A corresponds to the above-described black and white mode, and the threshold value stored in the threshold value register 168A is applied to the output of the image correction circuit 163A, thereby converting the image signal into binary data of white and black. . The grayscale processing circuit 165A applies binary data by applying a dither method or an error diffusion method to the signal output from the image correction circuit 163A, corresponding to the halftone mode. In addition, a selector 166A that selects one of the outputs of the comparator 164A and the density processing circuit 165A is provided.

The image correction circuit 163A performs γ correction as described above, and the γ correction table 167A that defines the characteristics of the correction can be rewritten by the control unit 11. Similarly, the threshold value register 168A that defines the level for separating white and black of the comparator 164A can also be rewritten by the control unit 11. These values are rewritten corresponding to the setting of the reading mode through the first reading mode setting key (A) 151.
The read image processing circuit 160B is configured in the same manner as the read image processing circuit 160A except that a scanning image sensor (CIS: Contact Image Sensor) constitutes the scanning unit. Then, the γ correction table and the threshold value defining the level for classifying white and black are rewritten according to the setting of the reading mode through the operation of the second reading mode setting key (B) 152.

  The transport unit 169 of the scanner unit 16A is a transport unit that is used both when the scanner unit 16A reads an image on the front side of the document and when the scanner unit 16B reads an image on the back side of the document. As shown in FIG. 3, a reading optical system using a CCD element 161A is disposed below the document transport path T. This reading optical system includes a light source lamp (for example, a cold cathode tube) 171, a light collector 172, a reflecting mirror 173, and a lens 174, and receives an image on the surface of a document (which is the lower surface of the document in FIG. The image is formed on the part. On the other hand, the CIS 161B is disposed above the transport path T. Although not shown, the CIS 161B includes a document illumination LED, a rod lens eye, and a photosensor eye in its casing.

  FIG. 3 is a structural diagram showing the concept of the basic configuration of the conveying means 169. The conveying means 169 is provided with rollers R1 to R5 and a belt (not shown) along the document conveying path T indicated by the arrow, and is rotated by the controller 11. The document is driven by a stepping motor or the like that controls the document. A CCD element 161A and a CIS 161B are arranged in the middle of the document transport path T, and the front and back surfaces of the document are read in parallel.

Here, the reading process control of the multi-function peripheral M configured as described above will be described in detail with reference to a flowchart.
FIG. 4 is a flowchart for explaining the control in the basic reading process of the multifunction peripheral M. The control unit 11 uses the first reading mode setting key (A) 151 and the second reading mode setting key (B) 152 of the operation unit 15 so that the user individually sets the reading mode for the front surface and the back surface of the document. It is set, and a start key (not shown) is operated to wait for an instruction to start reading (steps 201 to 202). When the start key operation is accepted, values corresponding to the reading mode are set in the γ correction table 167A and the threshold register 168A of the first scanner unit 16A, and the selector 166A is selected. The same applies to the second scanner unit 16B (steps 203-204). Next, when the rotation speed of a stepping motor (not shown) for driving the conveying means 169 is set and the reading scanning speeds of the reading modes set for the front surface and the back surface of the document are different from each other, the reading scanning speed is The scanning speed of the faster scanning mode is slowed down to match the scanning mode with a slower scanning speed (step 205). Such a difference in scanning speed may occur when the fine mode is set on one of the front and back sides of the document and the super fine mode is set on the other. When the reading process is started, one line of the image on the front side of the document is read (steps 206 to 207), and then one line of the image on the back side of the document is read (steps 208 to 209). (Step 210).

  Here, when the reading scanning speeds of the reading modes set for the front surface and the back surface of the original are different from each other, the reading scanning speed of the reading mode having a higher reading scanning speed is reduced. It is one.

  In the above-described multi-function device M, a CCD element and a CIS are used for the image sensors of the scanner unit 16A and the scanner unit 16B, but these may be the same type of image sensor.

1 is a block diagram illustrating a basic configuration of a multifunction peripheral M that is an embodiment of an image reading apparatus according to the present invention. FIG. 2 is a block diagram illustrating a basic configuration of a read image processing circuit. FIG. It is a structure figure which shows the concept of the basic composition of a conveyance means. It is a flowchart explaining the control in a reading process.

Explanation of symbols

15 Operation unit 151, 152 Mode setting key (reading mode setting means)
16A, B Scanner unit (image processing means)
160A, B Reading image processing circuit 169 Conveying means 161A CCD element (scanning means)
161B CIS (Operating means)

Claims (4)

In an image reading apparatus that reads and scans the front and back surfaces of the same document by first and second scanning means,
Reading mode setting means for individually setting a reading mode for each of the front and back sides of the document, and scanning and scanning each of the images on the front and back sides of the document according to the reading mode set by the reading mode setting means And an image processing unit that performs image processing. In claim 1,
When the scanning speed of the scanning mode set for each of the front surface and the back surface of the document is different from each other, the image processing means slows the scanning speed of the scanning mode in which the scanning speed is higher, An image reading apparatus configured to read and scan each of an image on the front side and an image on the back side in accordance with a reading mode having a slower speed. The method according to claim 1, further comprising conveying means for conveying the document.
Each of the first and second scanning means is an image reading apparatus disposed at two positions on the original conveying path of the conveying means. In any one of Claims 1-3.
Each of the first and second scanning units includes an image sensor that reads an original, and the image sensors are of different types.

Images