JP2021141377A - Image reading device - Google Patents

Abstract

To prevent, at a relatively low cost, a reduction in image quality at the rear end of a document due to the release of a nip between rollers.SOLUTION: An image sensor 2 reads an image of a document that passes through a predetermined image reading position on a conveyance path of the document. A sensor driving unit 2a moves the image sensor 2 in a direction perpendicular to a conveyance direction of the document. Of upstream side conveying rollers arranged at positions on the upstream side of the predetermined image reading position on the conveyance path of the document, a conveying roller 12a is closest to the predetermined image reading position and inclined from the direction perpendicular to the conveyance direction of the document. A controller 21 controls the sensor driving unit 2a to move the image sensor 2 so that the document being conveyed by the conveying roller 12a passes through the image reading position in accordance with the document being shifted in the direction perpendicular to the conveyance direction of the document.SELECTED DRAWING: Figure 2

Description

The present invention relates to an image reader.

When transporting a document by an automatic document feeder, one image reading device transports the document in a state where the direction of the document is tilted with respect to the transport direction, whereby the rear end of the document by the roller in front of the image scanning position. The fluctuation of the transport speed when the nip is released is suppressed to suppress the deterioration of the image quality (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-292279

However, in the above-mentioned image reading device, when the document passes through the image scanning position, the direction of the document is always tilted. Therefore, the tilt angle A of the document, the width W of the document, and the length L (lengths of the left and right sides). ) Is increased by dW (= W × cos (A) + L × sin (A) −W). It is necessary to use an image sensor, which increases the cost of the image reader.

The present invention has been made in view of the above problems, and an object of the present invention is to obtain an image reader that suppresses image quality deterioration due to release of a roller nip at the rear end of a document at a relatively low cost.

The image reading device according to the present invention includes an image sensor that reads an image of a document passing through a predetermined image reading position in a document transport path, and a sensor that moves the image sensor in a direction perpendicular to the document transport direction. Of the drive unit and the upstream transport roller arranged at a position upstream from the predetermined image reading position in the transport path, the closest to the predetermined image reading position and with respect to the transport direction of the document. As the tilted transport roller tilted from the vertical direction and the document being transported by the tilted transport roller shift in the direction perpendicular to the transporting direction of the document, the document reads the image. It includes a controller that controls the sensor driving unit to move the image sensor so as to pass through the position.

According to the present invention, it is possible to obtain an image reading device that suppresses image quality deterioration caused by releasing the nip of a roller at the rear end of a document at a relatively low cost.

The above or other objects, features and advantages of the present invention will be further clarified from the following detailed description along with the accompanying drawings.

FIG. 1 is a side view showing an internal configuration of an image reading device according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of arrangement of the image sensor 2 and the transfer rollers 12 and 13 in the image reading device shown in FIG. FIG. 3 is a block diagram showing an electrical configuration of the image reader shown in FIGS. 1 and 2. FIG. 4 is a diagram illustrating the operation of the image reading device shown in FIGS. 1 to 3.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing an internal configuration of an image reading device according to an embodiment of the present invention. The image reading device shown in FIG. 1 is a device such as a scanner machine, a copier, a facsimile machine, or a multifunction device.

The image reading device shown in FIG. 1 includes a device main body 1, contact glasses 1a and 1b arranged on the upper surface of the device main body 1, an image sensor 2, a sensor driving unit 2a, and a document cover 3. The document cover 3 includes an automatic document feeder 4.

The contact glass 1a is a transparent member on which a document is placed when an image is read without using the automatic document feeder 4. Further, the contact glass 1b is a transparent member through which the original is passed when the automatic document feeder 4 automatically conveys the original and reads the image of the original image.

The image sensor 2 is a sensor that optically reads an image of a document that passes through a predetermined image reading position in the document transport path when the image of the document image is read while the document is automatically conveyed by the automatic document feeder 4. Is. The image sensor 2 reads the original image line by line.

The image sensor 2 includes a light source (light emitting diode or the like) and a light receiving element (line sensor or the like), emits light by the light source, and detects the reflected light reflected by the document or the like through the contact glasses 1a and 1b by the light receiving element. Then, an electric signal corresponding to the amount of reflected light is output. The controller 21, which will be described later, receives this electric signal and generates a manuscript image (that is, image data of the manuscript image) based on this electric signal.

The document cover 3 is a member that can be surface-contacted with the contact glass 1a and is rotatably installed. The document is brought into close contact with the contact glass 1a, and ambient light is emitted from the contact glasses 1a and 1b to the inside of the device during image reading. Prevents incident on the glass. Further, the automatic document feeder 4 conveys the documents placed on the document tray 11 one by one by the transfer rollers 12 and 13, passes over the contact glass 1b, and discharges the documents to the discharge tray 14.

Further, the image reading position of the image sensor 2 can be changed by a drive device (not shown), and when the image reading is executed by using the automatic document feeder 4, the image reading position of the image sensor 2 is changed. The image sensor 2 is set to the passing position of the document on the contact glass 1b, and the image sensor 2 optically reads the image of the document conveyed by the automatic document feeder 4 when passing over the contact glass 1b. Here, the image sensor 2 is a color image sensor that reads original images of a plurality of colors such as RGB at different image reading positions in the transport direction.

In this embodiment, a CIS (Contact Image Sensor) is used as the image sensor 2, and when image reading is performed using the automatic document feeder 4, the image sensor 2 is arranged directly under the contact glass 1b. ..

The sensor drive unit 2a moves the image sensor 2 in a direction perpendicular to the document transport direction.

FIG. 2 is a diagram showing an example of arrangement of the image sensor 2 and the transfer rollers 12 and 13 in the image reading device shown in FIG.

For example, the sensor drive unit 2a includes a connecting rod 2b connected to the image sensor 2 by a screw mechanism and a motor 2c for rotating the connecting rod 2b. The image sensor 2 is moved in a direction perpendicular to the document transport direction.

The transport rollers 12 and 13 are driven by a predetermined driving force source (roller drive unit 22 described later), and transport the document 101 along the transport path.

The transport roller 12 is an upstream transport roller arranged at a position upstream from a predetermined image reading position in the transport path. The transport roller 12a is an inclined transport roller that is closest to a predetermined image reading position among the transport rollers 12 and is inclined from a direction perpendicular to the transport direction of the document.

The transport roller 13 is a downstream transport roller arranged at a position downstream from a predetermined image reading position in the transport path.

FIG. 3 is a block diagram showing an electrical configuration of the image reader shown in FIGS. 1 and 2.

The image reading device shown in FIG. 3 further includes a controller 21 and a roller driving unit 22. The controller 21 includes a processor for executing a program, an ASIC (Application Specific Integrated Circuit), and the like, and (a) electrically controls the roller drive unit 22 and the like to control the operations of the transfer rollers 12 and 13 and (b). ) The sensor drive unit 2a is electrically controlled to control the image reading position of the image sensor 2, and (c) an electric signal indicating a document image is received from the image sensor 2 and image data corresponding to the electric signal is generated. Then, a predetermined image process is executed on the image data. For example, since the document 101 is shifted by the transport roller 12a, image processing that suppresses distortion of the document image due to the rotation of the document 101 is executed.

The roller drive unit 22 is a drive unit (motor or the like) that drives the above-mentioned transport rollers 12 and 13.

Further, the controller 21 uses the sensor drive unit 2a so that the document passes through the image reading position as the document being conveyed by the transfer roller 12a shifts in the direction perpendicular to the document transfer direction. To move the image sensor 2.

Specifically, when the image sensor 2 detects that the tip of the document 101 has reached the image reading position (a), the controller 21 controls the sensor drive unit 2a to move the image sensor 2 to a predetermined position (initial). When the nip at the rear end of the document 101 by the transport roller 12a is released, the sensor drive unit 2a is controlled to stop the image sensor 2, and (c) the document 101 is set at the image reading position. When the image sensor 2 detects that the rear end has reached, the sensor drive unit 2a is controlled to return the image sensor 2 to the above-mentioned predetermined position (initial position).

When moving the image sensor 2 in a direction perpendicular to the transport direction of the document 101, the sensor drive unit 2a moves the image sensor 2 at a predetermined speed. The predetermined speed is set based on the transport speed of the document 101 and the inclination angle of the transport roller 12a. That is, this moving speed of the image sensor 2 is the same as the speed at which the document 101 shifts in the direction perpendicular to the transport direction of the document 101.

Next, the operation of the image reader will be described. FIG. 4 is a diagram illustrating the operation of the image reading device shown in FIGS. 1 to 3. FIG. 4A is a diagram showing a transport state and the position of the image sensor 2 before the tip of the document 101 is nipped into the transport roller 12a. FIG. 4B is a diagram showing a transport state and a position (movement) of the image sensor 2 when the document 101 is transported by the transport roller 12a. FIG. 4C is a diagram showing a transport state and the position of the image sensor 2 after the nip of the transport roller 12a at the rear end of the document 101 is released. FIG. 4D is a diagram showing a transport state and the position of the image sensor 2 after the image reading to the rear end of the document 101 is completed.

The controller 21 executes the document image reading using the automatic document feeder 4 as follows according to a user operation on an operation panel (not shown).

First, the controller 21 starts the operation of the image sensor 2 and controls the automatic document feeder 4 to start the transfer of the documents 101 one by one from the document tray 11.

In the automatic document feeder 4, the transfer roller 12 conveys the document 101 fed from the document tray 11 along the transfer path. Then, when the document 101 reaches the image reading position, the image sensor 2 reads the image of the document 101 line by line. After that, the transport roller 13 transports the document 101 and discharges it to the discharge tray 14.

Before the document 101 reaches the transport roller 12a, the document 101 goes straight without shifting in the direction perpendicular to the transport direction, for example, as shown in FIG. 4 (A).

During the period in which the document 101 is transported by the transport roller 12a, the document 101 goes straight in the transport direction while shifting in the direction perpendicular to the transport direction, for example, as shown in FIG. 4 (B). At that time, when the controller 21 detects the tip of the document 101 by the image sensor 2, the controller 21 reads the document image line by line from the tip of the document 101, and the sensor drive unit 2a adjusts the image sensor 2 to the shift of the document 101. Move it.

Then, at the timing when the nip of the document 101 is released by the transfer roller 12a, for example, as shown in FIG. 4C, the controller 21 stops the image sensor 2 at the sensor drive unit 2a to transfer the document 101 and transfer the document 101. When the image sensor 2 continues to read the image and then the image sensor 2 detects the rear end of the document 101, the sensor drive unit 2a places the image sensor 2 in its original position (initial position), for example, as shown in FIG. 4 (D). Move to position).

Since a part of the original image read during the period when the original 101 is conveyed by the conveying roller 12a is distorted, the controller 21 conveys the original 101 by the conveying roller 12a (conveying speed and inclination of the conveying roller 12a). Performs image processing that suppresses distortion of the original image in response to (corners, etc.).

The original image obtained in this manner (that is, the original image in which distortion is suppressed) is stored in a storage device (not shown) as an image data file, or transmitted to an external device (not shown) as an image data file. It may be printed by a printing device (not shown).

As described above, according to the above embodiment, the image sensor 2 reads the image of the document passing through the predetermined image reading position in the document transport path. The sensor drive unit 2a moves the image sensor 2 in a direction perpendicular to the document transport direction. The transport roller 12a is the closest to the predetermined image reading position among the upstream transport rollers arranged at positions upstream from the predetermined image reading position in the document transport path, and is relative to the document transport direction. It is tilted from the vertical direction. The controller 21 controls the sensor drive unit 2a so that the document passes through the image reading position as the document being conveyed by the transfer roller 12a shifts in the direction perpendicular to the document transfer direction. Then, the image sensor 2 is moved.

As a result, since the image sensor 2 is moved according to the shift of the document, the readable document width Wd required for the image sensor 2 can be small, the cost of the image sensor 2 is low, and the cost is relatively low. , It suppresses the deterioration of image quality due to the release of the roller nip at the rear end of the document (fluctuation of transport speed and vibration of the document when the nip is released).

It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the intent and scope of the subject and without diminishing the intended benefits. That is, such changes and amendments are intended to be included in the claims.

The present invention can be applied to, for example, a scanner machine, a multifunction device, and the like.

2 Image sensor 2a Sensor drive unit 12a Conveyor roller (an example of tilt conveyor roller)
21 controller

Claims (3)

An image sensor that reads an image of a document that passes through a predetermined image reading position in the document transport path,
A sensor drive unit that moves the image sensor in a direction perpendicular to the document transport direction, and a sensor drive unit.
Among the upstream transport rollers arranged at positions upstream from the predetermined image reading position in the transport path, the direction closest to the predetermined image reading position and perpendicular to the transport direction of the document. With an inclined transport roller inclined from
The sensor drive unit is moved so that the document passes through the image reading position as the document being transported by the tilt transfer roller shifts in a direction perpendicular to the transfer direction of the document. A controller that controls and moves the image sensor,
An image reading device comprising. When the tip of the document reaches the image reading position, the controller controls the sensor drive unit to start the movement of the image sensor from a predetermined position, and (b) the document by the tilt transfer roller. When the nip at the rear end is released, the sensor drive unit is controlled to stop the image sensor, and (c) when the rear end of the document reaches the image reading position, the sensor drive unit is controlled. The image reading device according to claim 1, wherein the image sensor is returned to the predetermined position. The sensor drive unit moves the image sensor at a predetermined speed in a direction perpendicular to the transport direction of the document.
The predetermined speed is set based on the transport speed of the document and the tilt angle of the tilt transport roller.
The image reading apparatus according to claim 1 or 2.

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