JPH11164101A - Original reader and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original reader of which the cost is low and the size is small. SOLUTION: A chart 20 is stuck to the back surface of an abutting plate 21 within an area which is the read range of a CCD. A first mirror unit 1 and a second mirror unit 4 are driven by a motor 16, and a pattern on the chart 20 is read by the CCD through glass 7. The motor 16 is controlled, based on output information from the CCD. The stoppage and speed change of the first mirror unit 1 and the second mirror unit 4 are controlled based on the patterns 27 and 28 of stoppage and the pattern 29 of speed change formed on the chart 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading apparatus such as a copying machine, an image reader, a facsimile or the like using a CCD or a contact sensor, and an image forming apparatus.

[0002]

2. Description of the Related Art FIG. 5 is a perspective view of a conventional device of this type, and FIG. 6 is a sectional view of the same device.

In FIG. 1, reference numeral 1 denotes a first mirror unit integrally having a halogen lamp 2 as a light source and a first mirror 3;
4 is a second mirror unit having a second mirror and a third mirror,
Reference numeral 5 denotes a lens, 6 denotes a CCD, and a platen glass 7
The original 8 placed above is read, and data is sent as a digital signal to the printer section 9 for recording. here,
The printer unit 9 is a laser beam printer,
A signal from the reading is irradiated on the drum 11 by a laser scanner of 10, and is developed, transferred and fixed by an electrophotographic process, and is stacked on a paper output tray of 12.

In FIG. 5, the first mirror unit 1 and the second mirror unit 4 are driven by a DC motor 16 via a pulley 14 and a timing belt 15 via 13 wires.

The DC motor 16 has a circular light-shielding plate 17 provided with a slit on the same axis as the DC motor 16 and detects the rotation of the motor based on the timing of the passage of light from the photointerrupter 18 to control the speed.

[0006]

However, in such a conventional example, in order to control the speed of the motor, the above-described light-shielding plate 17 and photo-interrupter 18 are required.
For this reason, it is necessary to form an encoder, thereby increasing the cost. In addition, in many cases, it is necessary to take extra space for the encoder in the depth direction, which is disadvantageous for miniaturization of the apparatus.

In particular, in order to perform high-resolution and high-speed scanning, it is necessary to precisely form finer slits in a limited space of the light-shielding plate, which has become difficult as a processing technique.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has as its object the following:
An object of the present invention is to provide a low-cost and small-sized document reading device.

[0009]

According to a first aspect of the present invention, there is provided a document reading device for reading an image on a document, and a driving device for moving at least one of the document and the document reading device. And a document reading apparatus for reading an image on a document by moving at least one of the document and the document reading means,
A control image signal is formed in an area that is within the reading area of the document reading means but outside the document reading area, and the driving is performed based on output information output from the document reading means that has read the control image signal. It is characterized by controlling the means.

The document reading apparatus may be any apparatus that reads a document by moving at least one of the document and the document reading means. The document reading apparatus may be any of a document table moving type and a document table fixed type. Is also good.

The reading means includes a CCD, a contact sensor, and the like. However, the present invention is not limited to the case where these elements themselves move, but also includes the case where an illumination system or an optical system for guiding image light to the reading means moves.

With this configuration, it is not necessary to provide a separate device for controlling the driving means such as the encoder, and the cost can be reduced.

Further, there is no need to secure a space for a device for controlling driving means such as an encoder, and the size of the document reading device can be reduced.

Since the control image signal is formed outside the document reading area, the reading of the document is not hindered.

According to a second aspect of the present invention, in the first aspect, the original is placed on a light-transmissive original table, and reads an image on the original through the original table. The control image signal is formed on the document table.

With this configuration, since the control image signal is formed on the same surface as the document to be read, the reading means can read the control image signal with approximately the same accuracy as the image on the document. The control accuracy of the driving means is improved.

In a third aspect based on the second aspect, the control image signal is provided at a portion of the document positioning member on the document table facing the document table.

As described above, the member on which the control image signal is formed is sandwiched between the surface of the document positioning member facing the document table and the document table, and the control member is positioned on the surface of the positioning member itself facing the document table. By forming an image signal, the control image signal is not stained, and a malfunction of the driving means due to the stain can be prevented, and the reliability is improved.

In a fourth aspect based on the second aspect, the control image signal is formed on the original platen itself.

If the control image signal is formed on the document table itself by printing or the like, it is possible to prevent a mounting error when the member on which the control image is formed is mounted, and such a separate member is unnecessary. Therefore, the cost can be reduced.

According to a fifth aspect of the present invention, in the first to fourth aspects, stopping, reversing, and changing the speed of at least one of the document and the document reading means are performed based on the control image signal. Features.

This eliminates the need for a sensor such as a photo-interrupter, which is necessary for stopping, reversing, and changing the speed, thereby reducing costs.

Further, there is no need to secure a space for sensors such as a photo interrupter, which is necessary for stopping, reversing, and changing the speed, and the size of the document reading apparatus can be reduced.

In a sixth aspect based on the first to fifth aspects, the original reading means is a CCD.

If a CCD is used as the document reading means, highly reliable image reading can be performed.

In a seventh aspect based on the first to fifth aspects, the original reading means is a contact sensor.

If a contact sensor is used as the document reading means, highly reliable image reading can be performed.

In an eighth aspect based on the first to seventh aspects, the driving means is a DC motor.

If a DC motor is used as the driving means, an inexpensive document reading apparatus can be provided.

According to a ninth aspect, in the first to seventh aspects, the driving means is an ultrasonic motor.

If an ultrasonic motor is used as the driving means, an encoder which is more expensive than a DC motor is not required, so that the effect of cost reduction is great.

According to a tenth aspect, there is provided an image forming apparatus having a document reading section for reading an image on a document, and forming an image of the document read by the document reading section on a recording material. An image forming apparatus comprising a document reading device according to any one of the first to ninth aspects of the present invention.

This makes it possible to provide a small-sized image forming apparatus at low cost.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

(First Embodiment) FIG. 1 shows a copying machine as a document reading apparatus according to a first embodiment of the present invention.
The same parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, there is no light-shielding plate and no photo-interrupter, and a chart 20 as a control image signal is attached in an area 19 which is a reading range of a CCD (not shown) as a document reading means. Paste,
This is the back surface of the butting plate 21 that determines the position of the document, and is sandwiched between the glass 7 as a document table and the butting plate 21 as a positioning member. Can read.
As described above, this is the reading range of the CCD, and does not hinder reading when the document is placed outside the setting range of the document.

FIG. 2 is a view in which the glass 7 is detached from the main body of the apparatus, the stand is set on the apparatus, and the back surface of the glass 7 is viewed through a glass.

The first mirror unit 1 and the second mirror unit 4 stop at the start standby time by reading the left side of the apparatus, that is, the portion 22 in the figure, and stop at the time of scanning.
Stop by reading part 3.

When the copy button is pressed, the DC motor 16 as a driving means starts rotating and the CCD moves to the chart 20.
I read. Reading movement, chart, CC
FIG. 3 shows the relationship between D and the accumulation time.

In FIG. 3, reference numeral 24 denotes a chart pattern, and when the speed is matched, the chart is designed so as to be matched at a cycle of 10 times of the accumulation time of the CCD. That is, the speed of the first mirror unit 1 is set to 75 mm / s
If the accumulation time of the CCD is 0.5 msec, the chart interval P = 75 (mm / sec) × 0.5 (msec) × 10 (times)
= 0.375mm. Therefore, when all white,
When the illumination light amounts are adjusted so that the CCD obtains an output of 0.5 V in 0.5 msec, if the speed is the same, the output of 25 areas in the drawing in the white part, that is, 0.5 × 10 = 5 ( Vm
sec) output.

On the other hand, when reading all black, 0 × 5 = 0
Output. On the other hand, when the speed is not the same, for example, when the speed is high as indicated by 26 in FIG. Therefore, the amount of light within 5 msec decreases as indicated by 26. For example, 5
If the output during the last accumulation enters half-black in msec, the output is only 0.25V, and as a whole,
The output is 9 × 0.5 + 1 × 0.25 = 4.75 (V · msec). The current or voltage value of the DC motor 16 may be controlled according to the area ratio. That is, in this case, the speed is set to 4.
75/5 = 0.95, that is, 95%. Even when reading all black, it is of course possible to control in a similar manner. When doubling the speed, control is performed so that the amount of light becomes half.

As described above, by controlling the motor using the CCD, it is not necessary to newly provide an encoder for the speed of the motor, thereby reducing the cost. Further, the space for the encoder, which is usually provided behind the motor, becomes unnecessary, and the depth of the device can be reduced.

On the other hand, in the present embodiment, the chart is provided behind the original butting plate so as to be sandwiched between the glass 7.

In this manner, the chart is not stained, the malfunction of the motor and the speed change due to the stain are prevented, and the reliability is improved. In addition, since the CCD is in the same plane as the document reading section, the CCD is focused, reading accuracy is improved, and speed control accuracy is improved.

Further, in this embodiment, reference numerals 22 and 23 in FIG.
As shown in the figure, a long all black area 27,
28 are provided. This is a control in which, when reading, when all black continues for a certain period of time or more, the operation is stopped.

When moving from the long black portion 27 or 28, that is, at the end portion 29, the interval between the chart patterns is shortened. In this way, the motor
In order to obtain the same amount of light within 10 accumulations, that is, within 0.5 × 10 = 5 msec, an attempt is made to obtain the output of 5 (V · msec) by reducing the speed of the motor. That is, by changing the pitch of the pattern, acceleration and deceleration can be performed smoothly.

As a result, a sensor such as a photo-interrupter, which is normally required for determining the stop position, becomes unnecessary,
Cost reduction.

Further, since the acceleration and deceleration of the first mirror unit 1 and the second mirror unit 4 can be performed simultaneously,
Vibration due to rapid startup can be prevented, and image quality can be improved.

(Second Embodiment) In the first embodiment, C
Although a CD is used as a document reading unit, a contact sensor may be used. Further, the reader section may be of a type in which the original reading means is fixed and the original platen glass moves. That is, regardless of the reading sensor and the scanning method, the motor may be controlled by the input of the document reading sensor.

(Third Embodiment) In the first embodiment, a DC motor is used as the driving means, but an ultrasonic motor may be used. Ultrasonic motors have the advantage of requiring little deceleration because they generate high torque at low speeds, but conversely, if you try to provide an encoder on the motor, the number of revolutions is smaller than that of a DC motor, In order to obtain the same resolution by the encoder, it is necessary to form a high-resolution signal pattern in the same space, and the encoder becomes expensive, so that the effect of cost reduction is high.

(Fourth Embodiment) The signal pattern is the first
In the embodiment, the original plate is formed so as to be sandwiched between the original plate butting plate on the original plate glass. In this case, the sticking mistake by the operator and the cost of parts as a chart reduce the cost.

(Fifth Embodiment) In the first embodiment, the speed control is performed based on the difference in the amount of accumulated light. However, when the amount of light in the illumination system fluctuates greatly, the amount of light varies even if there is no speed change. If the lower limit of the variation of the light amount is set as the slice level and the value is equal to or more than the slice level, it is better to determine that the image is completely white. For example, if the light amount variation is ± 10%,
0.5 × 0.9 = 0.45V or more is considered to be all white, and it is better to set it to 0.5V for calculation.

By doing so, it is possible to prevent the influence of the variation in the amount of light.

(Sixth Embodiment) In the first embodiment, all chart patterns are on the same line.
Various patterns may be arranged in parallel depending on the reading position of the.

For example, if the required speed is limited due to the specification, as shown in FIG. 4, several patterns with different pitches of the chart are arranged to control with different bits on the CCD and change the speed. Can be. Further, a stop position for each reading size may be described. When a plurality of patterns are arranged in parallel in this way when there is room in the CCD reading area, control becomes easier.

[0056]

As described above, according to the first aspect, the driving unit is controlled based on the output information output from the document reading unit that has read the control image signal.
It is not necessary to provide a separate device for controlling the driving means such as an encoder, and the cost can be reduced.

Further, there is no need to secure a space for a device for controlling driving means such as an encoder, and the size of the document reading device can be reduced.

Further, since the control image signal is formed outside the document reading area, the reading of the document is not hindered.

According to the second aspect of the present invention, since the control image signal is formed on the same surface as the document to be read, the reading means can read the control image signal with almost the same accuracy as the image on the document. As a result, the control accuracy of the driving means is improved.

According to the third aspect of the invention, the member on which the control image signal is formed is sandwiched between the surface of the document positioning member facing the document table and the document table, or the document positioning member itself faces the document table. By forming a control image signal on the surface side, the control image signal can be provided in a portion of the document positioning member on the document table facing the document table, so that the control image signal is not stained. In addition, malfunction of the driving means due to dirt can be prevented, and the reliability is improved.

If the control image signal is formed on the platen itself by printing or the like according to the fourth aspect of the present invention, it is possible to prevent a mounting error when the member on which the control image is formed is mounted, and to use such a separate member. Is unnecessary, so that the cost can be reduced.

According to the fifth aspect, the stop, reverse rotation, and speed change of at least one of the original and the original reading means are performed based on the control image signal, so that the stop, reverse rotation, and speed change are performed. This eliminates the need for a sensor such as a photo-interrupter, which is necessary for this purpose, thereby reducing costs.

Further, it is not necessary to secure a space for a sensor such as a photo-interrupter which is necessary for stopping, reversing, and changing the speed, so that the size of the document reading apparatus can be reduced.

According to the sixth aspect, since the CCD is used as the document reading means, highly reliable image reading becomes possible.

According to the seventh aspect, since the contact sensor is used as the document reading means, highly reliable image reading can be performed.

According to the eighth aspect of the present invention, as the driving means, DC
Since a motor is used, an inexpensive document reading device can be provided.

According to the ninth aspect, since an ultrasonic motor is used as the driving means, an encoder which is more expensive than in the case of a DC motor is not required, and the effect of cost reduction is great.

According to a tenth aspect, there is provided an image forming apparatus having a document reading section for reading an image on a document, and forming an image of the document read by the document reading section on a recording material. Since the document reading section is provided with the document reading apparatus according to the first to ninth aspects, it is possible to provide a small-sized image forming apparatus at low cost.

[Brief description of the drawings]

FIG. 1 is an exemplary perspective view of a copying machine according to a first embodiment, in which a part of a housing is omitted;

FIG. 2 is a diagram for explaining details of a chart of the copying machine according to the first embodiment;

FIG. 3 is a diagram for explaining a speed control method using a CCD.

FIG. 4 is a diagram showing details of a chart according to a sixth embodiment.

FIG. 5 is a perspective view in which a part of a housing of a copying machine according to a conventional example is omitted.

FIG. 6 is a cross-sectional view of a copying machine according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st mirror unit 4 2nd mirror unit 6 CCD 7 Platen glass 8 Document 16 DC motor 17 Shield plate 18 Photo interrupter 20 Chart

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tohru Shirakawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (10)

[Claims] 1. A document reading device for reading an image on a document, and a driving device for moving at least one of the document and the document reading device, and at least one of the document and the document reading device A document reading device that reads an image on a document by moving the control image signal in a region that is within the reading region of the document reading means but outside the document reading region, and reads the control image signal. An original reading device, wherein the driving unit is controlled based on output information output from the original reading unit. 2. A document reading apparatus, wherein the document is placed on a light-transmitting document table, and an image on the document is read through the document table, wherein the control image signal is on the document table. 2. The document reading device according to claim 1, wherein the document reading device is formed as follows. 3. The document reading apparatus according to claim 2, wherein the control image signal is provided at a portion of the document positioning member on the document table facing the document table. 4. The document reading apparatus according to claim 2, wherein the control image signal is formed on the document table itself. 5. The document reading apparatus according to claim 1, wherein at least one of the document and the document reading unit stops, reversely rotates, and changes the speed based on the control image signal. apparatus. 6. The document reading apparatus according to claim 1, wherein said document reading means is a CCD. 7. The document reading apparatus according to claim 1, wherein said document reading means is a contact sensor. 8. The document reading apparatus according to claim 1, wherein said driving means is a DC motor. 9. The document reading apparatus according to claim 1, wherein said driving means is an ultrasonic motor. 10. An image forming apparatus having a document reading section for reading an image on a document, and forming an image of the document read by the document reading section on a recording material, wherein the document reading section is provided. An image forming apparatus comprising the document reading device according to any one of claims 1 to 9.