JPH1056534A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the disturbance of an image which is caused by the inertia of running systems when reading is suspended and intermittent reading is restarted by decelerating and accelerating the running systems within an image reading area. SOLUTION: After running systems 1 and 2 are accelerated outside of an image reading area for a time t, the systems 1 and 2 are moved at a constant speed to read each line within the image reading area based on an image reading request signal for each line which comes from a host computer. When the image reading request signal which comes from the host computer is suspended within the image reading area in the middle of reading, the systems 1 and 2 are slowed down and stopped for a time t'(>t) and waits for an image reading request signal from the host computer. Also, the systems 1 and 2 are accelerated for a time t"(>t') and restarts reading when the constant speed is reached.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading a document image by moving a traveling system in a sub-scanning direction, and in particular, suspending and resuming reading by decelerating and accelerating the traveling system in an image reading area. To an image reading apparatus.

[0002]

2. Description of the Related Art In this image reading apparatus, generally, as shown by a solid line in FIG. 4, a traveling system starts moving from a home position and accelerates outside a region for image reading for a time t. Move at a constant speed,
When the image reading is completed, the time t is set outside the image reading area.
Decelerate and stop during In recent years, the acceleration time and the deceleration time outside the image reading area have been shortened with the increase in the reading speed.

Further, in recent years, as the size and weight of the image reading apparatus have been reduced and the time and distance of acceleration and deceleration of the traveling system have been shortened, one sheet of the original has been demanded in order to meet the demand for higher speed. A method of intermittently reading a part of the data without reading all of the data and reading the data in a thinned manner is regarded as important. Further, when the traveling system is moved and read based on an image reading request signal sent line by line from the host computer, the image reading request signal from the host computer is interrupted due to the processing of the host computer. Sometimes, the movement of the traveling system is stopped, and when the image reading request signal is input again, the movement of the traveling system is restarted to perform intermittent reading.

In the conventional intermittent reading method, the traveling system is accelerated for a time t outside the image reading area, and is moved at a constant speed in the image reading area to perform reading. As shown by a broken line in FIG. Reading is interrupted for intermittent reading in the reading area, decelerated and stopped during time t, and then read at a constant speed after acceleration for another time t to resume reading. That is, in the conventional intermittent reading method, the time t and distance for acceleration and deceleration outside the image reading area are applied to the time and distance for acceleration and deceleration inside the image reading area as they are.

Other conventional intermittent reading methods include, for example, Japanese Patent Application Laid-Open Nos.
No. 26173, JP-A-4-199978, JP-A-6-37984, JP-A-6-205181 and JP-A-6-31315.

[0006]

However, in the above-mentioned prior art, the time and distance for acceleration and deceleration outside the image reading area when performing intermittent reading are applied to the time and distance for acceleration and deceleration within the image reading area as they are. Therefore, if the time and distance of acceleration and deceleration outside the image reading area are shortened with the increase of the reading speed, the time and distance of acceleration and deceleration within the image reading area are also shortened, and as a result, due to the inertia of the traveling system, There is a problem that image distortion, shaking, dropout and the like due to uneven reading occur.

The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide an image reading apparatus capable of preventing disturbance of an image due to inertia of a traveling system when performing intermittent reading.

[0008]

According to a first aspect of the present invention, there is provided a traveling system having at least a light source for illuminating a document and a mirror for reflecting reflected light of the document illuminated by the light source. In the image reading apparatus in which the moving system is moved in the sub-scanning direction by a stepping motor, the time for interrupting reading in the image reading area and decelerating the running system is shorter than the time for accelerating and decelerating the running system outside the image reading area. And a control means for controlling the stepping motor so as to increase the length of the stepping motor.

A second means is the first means, wherein the control means accelerates and decelerates the traveling system outside the image reading area, and the traveling system stops reading in the image reading area halfway. The deceleration is changed according to the scaling factor, and the deceleration time is changed according to the scaling factor.

A third means is that, in the second means, the control means performs reading in the image reading area on the way based on the acceleration time and the deceleration time until the reading speed at the maximum magnification is reached. It is characterized in that the time during which the traveling system is decelerated by interruption is changed.

A fourth means is an image reading apparatus for moving a traveling system, at least equipped with a light source for illuminating the original and a mirror for reflecting the reflected light of the original illuminated by the light source, in a sub-scanning direction by a stepping motor. In the case where reading is resumed in the image reading area, the acceleration of the running system is started and fixed when the reading is restarted in the image reading area from the time when the deceleration of the running system is started and stopped when reading is interrupted in the image reading area. And control means for controlling the stepping motor so that the time required to reach the reading speed becomes longer.

A fifth means is the fourth means, wherein the control means starts and stops deceleration of the traveling system when reading is interrupted in the image reading area, When reading is restarted, the acceleration of the traveling system is started and the acceleration until reaching a certain reading speed is changed according to the magnification.

A sixth means is that, in the fifth means, the control means performs the reading in the image reading area on the way based on the acceleration time and the deceleration time until the reading speed at the maximum magnification is reached. The time required to start and stop the deceleration of the traveling system when stopping and the time required to start accelerating the traveling system and reach a certain reading speed when resuming reading in the image reading area are changed. It is characterized in that it is changed according to the magnification.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the image reading apparatus according to the present invention, FIG. 2 is a timing chart for explaining speed control of the traveling system of FIG. 1, and FIG. 5 is a timing chart for explaining speed control.

In FIG. 1, a first traveling unit 1 is equipped with a light source for illuminating a document and a first mirror, and a second traveling unit 2 is equipped with second and third mirrors. The second traveling unit 2 includes a stepping motor 3
To move at a speed ratio of 2: 1. First traveling unit 1
The reflected light of the document illuminated by the light source is sequentially reflected by the first mirror and the second and third mirrors of the second traveling unit 2, guided to the light receiving surface of a reading sensor such as a CCD, and photoelectrically converted.

The stepping motor 3 is controlled by a controller 4. The controller 4 causes the traveling units 1 and 2 to move the scanning units 3 line by line in the reading area based on an image reading request signal sent line by line from a host computer (not shown). The stepping motor 3 is controlled to move to. Then, image data read by a reading sensor (not shown) is transferred to the host computer line by line.

When the image reading request signal for each line from the host computer is interrupted due to the processing of the host computer, the controller 4 interrupts the movement and reading of the traveling units 1 and 2, and Waits for an image reading request signal from. When the image reading request signal is sent again from the host computer, the controller 4 intermittently reads the document by restarting the movement and reading of the traveling units 1 and 2.

The traveling speed of the traveling units 1 and 2 will be described with reference to FIG. First, when the image reading request signal for each line from the host computer is not interrupted during reading, the traveling system (the first and second traveling units 1, 2, and so on) is in the home position as shown by the solid line. After moving from the image reading area and accelerating during the time t outside the image reading area, it moves at a constant speed in the image reading area based on the image reading request signal for each line from the host computer, and the image reading is completed. Then, it decelerates and stops during time t outside the image reading area.

In contrast, 1 from the host computer
When the image reading request signal for each line is interrupted in the middle of reading, the traveling systems 1 and 2 similarly accelerate during the time t outside the image reading area, and move within the image reading area for each line from the host computer. To read at a constant speed based on the image reading request signal.
If the image reading request signal from the host computer is interrupted in the image reading area in the middle of reading, the image reading request signal is decelerated and stopped during the time t '(> t) as shown by the broken line, and the image reading from the host computer is stopped. Wait for a request signal. Then, when the image reading request signal from the host computer is sent again, the image is accelerated during the time t and the reading is restarted when the speed becomes constant, and when the image reading is completed, the image is outside the image reading area during the time t. Decelerate and stop.

Therefore, according to the above embodiment, when the intermittent reading is performed, the reading is interrupted and the traveling systems 1, 2 are stopped.
The time t 'for decelerating and stopping is longer than the time t for accelerating and decelerating during the time t outside the image reading area to gradually stop the traveling system. As a result, the inertia of the traveling systems 1 and 2 causes It is possible to prevent image distortion such as image distortion, shaking, and dropout due to uneven reading.

FIG. 3 shows the speeds of the traveling systems 1 and 2 when reading at the same magnification and at the time of reducing reading. Here, when the original image is scaled, it is electrically performed in the main scanning direction,
In the sub-scanning direction, the reading speed of the traveling systems 1 and 2 is changed, and the reading speed is slower at the time of enlargement and earlier than at the time of reduction. Therefore, as shown in FIG. 3, when decelerating to interrupt reading, the acceleration at the time of reduction (−α
3) is made slower than the acceleration α1 at the same magnification. When acceleration is performed to restart reading, the acceleration α2 at the time of reduction is made equal to or slower than the acceleration α1 at the same magnification.

Since the reading speed of the traveling systems 1 and 2 is the slowest at the time of the maximum magnification, the acceleration time and the deceleration time until the reading speed at the maximum magnification is reached are used as a reference.
By changing the time for decelerating the traveling systems 1 and 2 by interrupting reading in the image reading area on the way,
Even when the reading speed varies depending on the magnification, it is possible to prevent the disturbance of the image due to the inertia of the traveling systems 1 and 2 when performing the intermittent reading.

Next, a second embodiment will be described with reference to FIGS. FIG. 5 is a timing chart for explaining speed control of the traveling system of FIG. 1 in the second embodiment, and FIG. 6 is a diagram for explaining speed control when the traveling system of FIG. 1 is contracted in the second embodiment. It is a timing chart.

In this embodiment, as shown in FIG. 5, when the image reading request signal from the host computer is interrupted in the middle of reading in this image reading area, it decelerates and stops during time t ', and Wait for an image reading request signal. Then, when the image reading request signal is sent again from the host computer, the reading is restarted when the speed is accelerated during the time t "(> t ') and reaches a constant speed.

Therefore, according to the second embodiment, when the intermittent reading is performed, the reading is interrupted and the running systems 1 and 2 are accelerated to a constant speed from the time t 'at which the running systems 1 and 2 are decelerated and stopped. Since the time t ″ before the image reading is long, it is possible to prevent image distortion such as image distortion, shaking, and dropout due to uneven reading at the time of restart due to the inertia of the traveling systems 1 and 2.

FIG. 6 shows the speeds of the traveling systems 1 and 2 at the time of reading at the same magnification and at the time of reduction reading. Here, when the original image is reduced, the reading speed of the traveling systems 1 and 2 is set to be faster than that at the time of equal magnification. Therefore, when the image reading request signal from the computer is interrupted during reading as shown in FIG. It decelerates and stops during time t ₁ ′ (<t ₁ ″), and accelerates during time t ₁ ″ when resuming. The time t ₁ ′ and t ₁ ″ at the time of reduction are equal to the time t ′ at the time of equal magnification,
Inversely proportional to the reduction ratio from t ″.

Since the reading speeds of the traveling systems 1 and 2 are the slowest at the time of maximum enlargement and the fastest at the time of maximum reduction, the magnification is changed based on the acceleration time and the deceleration time until the reading speed at the maximum enlargement is reached. The time t ₁ ′, t ₁ ″ is controlled according to the magnification by controlling the time t ₁ ′, t ₁ ″ to be the shortest at the time of maximum magnification and the longest at the time of maximum reduction corresponding to the time t ′, t ″ of the same magnification. Even when the speeds are different, it is possible to prevent image disturbance at the time of restart due to inertia of the traveling systems 1 and 2 when performing intermittent reading.

[0028]

As described above, according to the first aspect of the present invention, the traveling system is accelerated outside the image reading area.
The stepping motor is controlled so that the time during which reading is interrupted in the image reading area and the travel system is decelerated becomes longer than the time during which the image is decelerated. Can be prevented.

According to the second aspect of the present invention, an acceleration for accelerating and decelerating the traveling system outside the image reading area;
In the image reading area, reading is interrupted halfway and the acceleration for decelerating the traveling system is changed according to the magnification, and the deceleration time is changed according to the magnification, so that the reading speed varies according to the magnification. Also in this case, it is possible to prevent the image from being disturbed due to the inertia of the traveling system when performing the intermittent reading.

According to the third aspect of the present invention, reading is interrupted halfway in the image reading area on the basis of the acceleration time and the deceleration time until the reading speed at the maximum magnification is reached. Since the time for decelerating is changed, it is possible to prevent the image from being disturbed by the inertia of the traveling system when performing the intermittent reading even when the reading speed varies depending on the magnification.

According to the fourth aspect of the present invention, when reading is restarted in the image reading area, the time required to start and stop the deceleration of the traveling system when reading is interrupted in the image reading area is reduced. Since the stepping motor is controlled so that the time from starting acceleration of the traveling system to reaching a certain reading speed becomes longer, image disturbance due to inertia of the traveling system at the time of resuming when performing intermittent reading is prevented. be able to.

According to the fifth aspect of the present invention, when the reading is interrupted in the middle of the image reading area, the acceleration for starting and stopping the deceleration of the traveling system, and when the reading is restarted in the image reading area. Since the acceleration from the start of acceleration of the traveling system to the reaching of a certain reading speed is changed in accordance with the scaling factor, even when the reading speed differs depending on the scaling factor, the acceleration depends on the inertia of the traveling system at the time of resumption. Image disturbance can be prevented.

According to the present invention, when the reading is interrupted in the image reading area on the basis of the acceleration time and the deceleration time until the reading speed at the maximum magnification is reached, the traveling system is stopped. Since the time required to start and stop the deceleration and the time required to start acceleration of the traveling system to reach a certain reading speed when resuming reading in the image reading area are changed according to the magnification, Even when the reading speed varies depending on the magnification, it is possible to prevent the image from being disturbed due to the inertia of the traveling system at the time of restart.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a timing chart for explaining speed control of the traveling system of FIG.

FIG. 3 is a timing chart for explaining speed control at the time of reduction of the traveling system of FIG. 1;

FIG. 4 is a timing chart for explaining conventional speed control of a traveling system.

FIG. 5 is a timing chart for explaining speed control of the traveling system of FIG. 1 in the second embodiment.

FIG. 6 is a timing chart for explaining speed control at the time of reduction of the traveling system of FIG. 1 in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st traveling unit 2 2nd traveling unit 3 Stepping motor 4 Controller

Claims (6)

[Claims] 1. An image reading apparatus comprising: a stepping motor for moving a traveling system including at least a light source for illuminating a document and a mirror for reflecting reflected light of the document illuminated by the light source in a sub-scanning direction; An image provided with control means for controlling the stepping motor so that the time during which reading is interrupted in the image reading area and the travel system is decelerated becomes longer than the time required to accelerate and decelerate the system outside the image reading area. Reader. 2. The image processing apparatus according to claim 1, wherein the control unit is configured to change an acceleration for accelerating and decelerating the traveling system outside the image reading area and an acceleration for decelerating the traveling system by interrupting reading in the image reading area according to a magnification. 2. The image reading device according to claim 1, wherein the deceleration time is changed in accordance with the scaling factor. 3. The control unit decelerates the traveling system by interrupting reading in an image reading area on the basis of an acceleration time and a deceleration time until the reading speed at the maximum magnification is reached. 3. The image reading device according to claim 2, wherein the time is changed. 4. An image reading apparatus comprising: a stepping motor for moving a traveling system having at least a light source for illuminating a document and a mirror for reflecting reflected light of the document illuminated by the light source in a sub-scanning direction; When reading is resumed in the image reading area, the acceleration of the running system is started when the reading is restarted in the image reading area, and a constant reading speed is set. An image reading apparatus comprising: a control unit that controls the stepping motor so that the time until the arrival is longer. 5. The control device according to claim 1, wherein the control unit includes: an acceleration unit configured to start and stop deceleration of the traveling system when reading is interrupted in the image reading area; 5. The image reading apparatus according to claim 4, wherein an acceleration from when the system is started to when the reading speed reaches a predetermined reading speed is changed in accordance with the magnification. 6. The system according to claim 1, wherein the control unit is configured to decelerate the traveling system when reading is interrupted in the image reading area on the basis of an acceleration time and a deceleration time until the reading speed at the maximum magnification is reached. Starting and stopping, and, when resuming reading in the image reading area, changing the time from starting acceleration of the traveling system to reaching a constant reading speed according to the magnification. The image reading device according to claim 5, wherein