JPH06133115A - Picture reader - Google Patents

Abstract

PURPOSE:To always monitor the position of a scanning body by counting up or counting down the number of revolutions of a motor driving the scanning body scanning optically an original reciprocally in response to the direction of the rotation. CONSTITUTION:The ON/OFF control of a DC motor, the control of the direction of rotation, the ON/OFF control of a brake and the control of number of revolutions are executed by a CPU 112 through a control line 114. Furthermore, an up-down counter 113 is controlled by the CPU 112 through a control line 116 and counts encoder pulses outputted from the DC motor 103 at every prescribed rotation angle through a control line 115. Then the up-count or down- count is switched by the rotation direction detection signal of the DC motor 103 outputted from the CPU 112. Thus, even when trimming processing is implemented, the processing is restored up to this side of the trimming area and then the reading of the trimming area is implemented and the original read time is shortened.

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 used in a color copying apparatus or the like.

[0002]

2. Description of the Related Art In an image reading apparatus used for a color copying apparatus or the like, a stepping motor has been conventionally used as a means for driving a scanner for reading a document image.

FIG. 18 is a conceptual diagram of an image reading apparatus of this type, in which a DC motor 501 and a carriage 502 are connected by a wire (not shown), and a home position sensor 503 is provided and is indicated by a broken line from a home position. As described above, the image of the document 504 is scanned by reciprocating between the document reading position farthest from the home position. Further, the leading edge position of the document 504 (TO
A D-TOP sensor 505 is provided in P).

Further, the sensor 50 is attached to the carriage 502.
A shielding plate 506 for shielding the light from the light sources 3, 505 is attached. A stop sensor 507 for detecting the brake timing of the DC motor 501 is provided near the home position side of the D-TOP sensor 505.

In the above image reading apparatus, after the carriage 502 has passed the position of the D-TOP sensor 505, the encoder pulses output from the DC motor 502 at every predetermined rotation angle are counted, and the carriage 502 is counted.
The DC motor 501 is controlled so as to return to the home position when is moved to a predetermined reading width. Then, when the carriage 502 returns to the home position after the reading is completed, the stop sensor 507 causes the carriage 5 to move.
DC motor 5 so that 02 stops at the home position
02 is controlled (first conventional example).

As another method for detecting the document size in the image reading apparatus, a method using a plurality of optical sensors each including a light emitting element and a light receiving element (second conventional example)
Alternatively, a method (third conventional example) in which a document is pressed by a reflection pressure plate and a document area other than the reflection pressure plate is determined from an image read by an image reading sensor is widely known.

[0007]

However, in the first conventional example described above, since the encoder pulse is output regardless of the moving direction of the carriage 502, the carriage 5
The 02 position cannot always be monitored. Therefore, when performing so-called trimming processing in which only a partial area of the original 504 is reproduced and output, it is necessary to scan the entire surface of the original table by prescan, return to the home position once, and scan again to the trimming position. However, there is a problem that it takes a long time to read a document.

Further, the carriage 5 is read after the document reading is completed.
When 02 returns to the home position, D as described above
Since the stop sensor 507 is provided to obtain the timing to start the braking of the C motor 501, there is a problem that the manufacturing cost becomes high.

Further, in the above-mentioned second conventional example, since each optical sensor is installed at a place where the legal document size such as B5 and A4 size can be identified, the document size can be roughly detected. There is.

Further, in the third conventional example, when a document is fed when the reflection pressure plate is removed and a document feeder or the like is attached, the document area cannot be determined and the size of the document is detected. There is a problem that you cannot do it.

In view of the above conventional problems, it is an object of the present invention to provide an image reading apparatus which is inexpensive, can read an original in a short time, and can accurately detect the size of the original. .

[0012]

To achieve the above object, the present invention provides a scanning body for optically scanning a document, a motor for driving the scanning body, and a pulse for each predetermined rotation angle of the motor. In an image reading apparatus provided with a pulse generating means for generating, a detecting means for detecting a rotating direction of the motor, and the number of pulses generated by the pulse generating means are counted up according to the rotating direction detected by the detecting means. Alternatively, it has a counter means for down-counting and a control means for controlling the position of the scanning body based on the count value of the counter means.

The present invention further comprises image reading means for optically reading a document and outputting an electric image signal,
Specific pattern recording means for recording a specific pattern on the surface of the original pressing member for pressing the original, and image discriminating means for discriminating whether or not the specific pattern is included in the image signal read by the image reading means. When the image signal is determined to include the specific pattern by the image determining means, the image is determined to be an image obtained by reading the surface of the document pressing member.

Further, it is also preferable that the image discriminating means discriminates whether or not it is a specific pattern in a unit of a fixed magnitude of the image signal, and the original is read from the image signal read by the image reading means. It is also preferable to determine whether or not the pattern is a specific pattern by determining the tint of the pressing surface.

Further, preferably, the original area is detected based on the discrimination result of the image discrimination means,
Further, it is characterized in that it comprises means for detecting whether or not the document pressing member is closed, and has prohibition means for inhibiting the operation of the image discriminating means when the document pressing member is open. .

[0016]

According to the present invention, the rotation number of the motor for reciprocally driving the scanning body for optically scanning the original is up-counted or down-counted according to the rotation direction. Can be constantly monitored.

Further, according to the present invention, it is possible to form a specific pattern on the surface for pressing the document and detect the size of the document based on the pattern hidden by the document. Further, the size of the document can be detected by using the size of the image signal as a unit or by the tint of the document pressing surface.

[0018]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic view showing an embodiment of an image copying apparatus equipped with an image reading apparatus according to the present invention. The image copying apparatus includes a document feeding section 1 and a document reading unit for reading a document. The unit (image reading device) 101 and the printer unit 300 for copying the read document.

In the printer unit 300, specifically, the polygon scanner 301 sequentially scans C, M, Y, and K image data with a laser beam, and the M image forming unit 302, the C image forming unit 303, and the Y image are scanned. Forming unit 304 and K image forming unit 30
At 5, an electrostatic latent image of each color is formed. Each of the image forming units 302 to 305 develops an electrostatic latent image with a toner, a photosensitive drum 318 irradiated with a laser beam, a primary charger 315 that charges the photosensitive drum 318 to a predetermined potential before exposure. And a developing device 313. Also, the developing device 3
A sleeve 314 for applying a developing bias is provided inside 13.

Further, in each of the image forming sections 302 to 305, the photosensitive drum 3 is discharged by discharging from the back surface of the transfer belt 306.
Transfer charger 319 for transferring the toner image on 18 onto the transfer paper
A cleaner 317 that cleans the residual toner on the surface of the drum 318 after the transfer, and an auxiliary charger 316 that neutralizes the surface of the photosensitive drum 318 cleaned by the cleaner 317 so that the primary charger 315 can charge the toner satisfactorily. And a pre-exposure lamp 330 for erasing the residual charge on the drum 318.
Is provided.

The transfer papers stored in the cassettes 309 and 310 are taken in by the paper feed unit 308, and the transfer belt roller 312 rotates the transfer belt 306 and forms a pair with the adsorption charger 311 to transfer the transfer papers. Belt 306
Adsorb on top. The leading edge of the transfer sheet attracted and conveyed by the transfer belt 306 is detected by the sheet leading edge sensor 329, and then a toner image is transferred and superposed on each of the transfer chargers 319 of the image forming units 302 to 305 so that the transfer sheet is discharged. The device 324 facilitates separation from the transfer belt 306. The signal detected by the paper edge sensor 329 is sent to the reading unit 101 and used as a sub-scanning synchronization signal when sending a video signal from the reading unit 101 to the printer unit 300.

In the peeling charger 325, the transfer paper is the transfer belt 3.
The image is prevented from being disturbed due to peeling discharge at the time of separation from 06, and the pre-fixing chargers 326 and 327 compensate the attracting force of the toner on the transfer paper after separation to prevent the image from being disturbed.
Then, this toner image is thermally fixed by the fixing device 307. Further, the transfer belt 306 from which the transfer paper has been separated is destaticized by the destaticizing chargers 322 and 323 to be electrostatically initialized, and the dirt is removed by the belt cleaner 328.

FIG. 2 is a diagram showing a first embodiment of the document reading unit 101. The first carriage 104 and the second carriage 105 are connected to a wire (not shown) with respect to the DC motor 103, and are shown by solid lines. By reciprocating between the home position shown and the reading position farthest from the home position shown by the broken line, the image of the original 102 placed on the original glass 102 'is scanned. A home position sensor 107 is provided at the home position, and D-T is provided at the leading edge position (TOP) of the original 102.
An OP sensor 106 is provided. Sensors 106, 1
07 and the stop sensor 111 are composed of photo interrupters.

The first carriage 104 has a sensor 106,
A shield plate 108 for blocking the light of 107 and 111 is attached, and after the first carriage 104 has passed the position of the D-TOP sensor 106, the encoder pulse output from the DC motor 103 at every predetermined rotation angle is increased as described later. Counted by the down counter, the DC motor 103 is controlled to return to the home position when the first carriage 104 moves to a predetermined reading width. Then, when the first carriage 104 returns to the home position after the completion of reading, a stop sensor 111 is provided to detect the timing to start the braking of the DC motor 103 so that the first carriage 104 stops at the home position. The DC motor 103 is controlled. In addition, the second carriage 105 is 1/100 of the first carriage 104.
Follow at a speed of 2.

FIG. 3 is a block conceptual diagram showing a drive control system of the DC motor 103. The CPU 112 controls ON / OFF of the DC motor 103, rotation direction control, brake ON / OFF control, and rotation speed control. Etc. are control lines 114
Done through.

The up / down counter 113 is controlled by the CPU 112 via the control line 116, counts the encoder pulses output from the DC motor 103 for each predetermined rotation angle via the control line 115, and outputs from the CPU 112. Up-counting or down-counting is switched by the output rotation direction detection signal of the DC motor 103.

Returning to FIG. 2, the reflected light of the original document illuminated by the pair of light sources 110 provided on the first carriage 104 is imaged on the CCD 151 by the lens 109. The CCD 151 is provided with RGB filters of three colors, and the CCD 151 converts the reflected light of the original document into R, G, and B electric signals. Then, as shown in FIG.
The electric signal from 151 is converted into, for example, an 8-bit digital signal by an A / D (analog / digital conversion) unit and an S / H (sample hold) unit 152. Next, this image data is corrected by the shading correction unit 153 and the input masking unit 154, and is enlarged or reduced in the main scanning direction by the magnification processing unit 155 during the magnification operation. Next, the R, G, and B image data are converted into C (cyan), M (magenta), and Y (yellow) image data by the LOG conversion unit 156, compressed by the encoder unit 157, and then stored as memory data. It is stored in the memory unit 158 via the controller 171.

C, M, stored in the memory unit 158,
The Y image data is read in synchronization with each color of the printer unit 300, expanded by the decoder unit 159, and then output to the masking and UCR (undercolor removal) unit 160. Then, this image data is stored in the γ correction unit 161.
A known correction is performed by the edge enhancement unit 162, and is output to the printer unit 300 (FIG. 1) via the video processing unit 163.

The memory address controller 172
As will be described later, each of the up / down switching signals R0T1 and R0T for the up / down counter in the X (main scanning) direction and the up / down counter in the Y (sub-scanning) direction.
2 and a select signal R0T0 from the selector described later are output.

Here, when the image data is stored in the memory unit 158, the encoder unit 157 compresses the data. For example, in FIG. 5, when one square corresponds to one pixel, and each pixel includes 8-bit CMY data, 4 pixels × 4 lines, that is, 16 pixels of data are regarded as one block, and L *, a Converted to color component signals of * and b *, and 16 pixels x 3 colors x 8 bits = 384
Bit data is compressed into 32-bit data with a fixed length of 1/12.

When the data is read from the memory unit 158, the decoder unit 159 expands the CMYK data into 24-bit data, and the 24-bit data is masked by the masking unit 160 to restore the CMYK image data into 8-bit image data.

As described above, the steps of compressing, storing and decompressing the image data are necessary because the image forming section 302 for each color
This is because when the positions of 305 are deviated from each other, the positions of the image data required by the image forming units on the screen are different from each other at a certain point of time. , The memory unit 158 is used. Further, the reason why the compression and decompression are performed is to reduce the capacity of the memory unit 158 by reducing the image data amount.

Next, referring to FIG. 6, the memory unit 158
The configuration of will be described. First, each up / down switching signal RO for the X (main scanning) direction up / down counter 182 and the Y (sub-scanning) direction up / down counter 183.
T1, ROT2, and the select signal RO of the selector 184
T0 is input from the memory address controller 172 (FIG. 4).

The signal selected by the selector 184 is
The coordinates-address conversion unit 185 converts the address into an address in the memory 187. The memory 187 is, for example, DRA.
The memory control unit 186 is configured by R of the memory 187.
It outputs AS, CAS, and WE signals (all active at low level). That is, the up / down switching signals ROT1 and ROT2 can be used to change the address reading direction in the XY directions, and the select signal R
Since the XY coordinates can be converted by OT0, eight types of image data can be output as shown in FIGS. 7A to 7H for the image “F”. Note that FIG.
Since (b) to (h) are known combinations of mirror inversion and rotation processing in 90 ° units, detailed description thereof will be omitted.

Next, referring to FIG. 8, the DC motor 1
The control of No. 03 will be described. First, the up / down counter 1
13, the shield plate 108 is the home position sensor 107.
Is blocked by the CPU 112 and reset by the CPU 112,
Start counting. FIG. 8A shows the count value of the up / down counter 113, and this count value is proportional to the distance between the home position and the first carriage 104. Note that FIG. 8 shows an operation in the case of trimming a part of a document as shown by the hatched portion in FIG. 9, and the trimming area is designated in advance via a digitizer (not shown).

Further, FIG. 8B shows an ON / OFF signal for the DC motor 103, which is ON at "H" and "L".
8C is OFF, and FIG. 8C shows the rotation direction control signal F / b * for the DC motor 103, which is forward when it is “H” and backward when it is “L”. Also, FIG. 8 (d) shows DC
The rotation direction signal CW / CWW * from the motor 103 indicates the actual rotation direction. The rotation direction is "H", and the rotation direction is forward, and the rotation direction is "L".

When a copy start button (not shown) is pressed in the standby section A, the CPU 112 causes the DC motor 103 to operate.
ON / OFF signal (b) and rotation direction control signal F /
Both b * (c) become “H”, the DC motor 103 rotates in the forward direction, and the first carriage 104 moves forward. The up / down counter 113 is reset at the home position and then the rotation direction signal CW from the DC motor 113 is output.
Start counting up based on / CWW * (d),
Prescan is performed (section B).

Next, the CPU 112 causes the rotation direction control signal F / b * to move the first carriage 104 backward.
When (c) is set to "L", the first carriage 104 does not immediately move backward due to inertia, but starts to move backward after moving forward for a while (d) (section C). Therefore, this section C
Since the DC motor 103 is rotating normally, the up / down counter 113 is counting up.

Then, when the DC motor 103 starts reverse rotation, the up / down counter 113 causes the DC motor 10 to rotate.
3 starts down-counting based on the rotation direction signal CW / CWW * (d) (section D), the CPU 112 monitors the count value of the up-down counter 113, and only a predetermined distance from the preset trimming area. ON / OFF signal for the DC motor 103 at the returned position (b)
And the rotation direction control signal F / b * (c) are both set to "L", and the first carriage 104 is stopped (section E).

When the CPU 112 again sets both the on / off signal (b) and the rotation direction control signal F / b * (c) to "H", the DC motor 103 rotates in the forward direction and the first
The carriage 104 moves forward, and the up / down counter 11
3 counts up. Here, the trimming area is read and the read data is written in the memory unit 158 (section F). The CPU 112 monitors the count value of the up-down counter 113, and when the reading of the trimming area is completed, the rotation direction control signal F / b * (c) is set to “L” to move the first carriage 104 backward (section G ), The shield 108 is the stop sensor 11
When the optical path of 1 is blocked, the speed of the DC motor 103 is reduced, and when the shielding plate 108 blocks the optical path of the home position sensor 107, the on / off signal (b) is set to "L" (section H).

Therefore, according to the above embodiment, since the current position of the first carriage 104 is monitored by the count value of the up / down counter 113, if the trimming process is performed, it is possible to return to the reading start position of the trimming area after the prescan. Good. Therefore, it is possible to constantly monitor the position of the first carriage 104 and shorten the reading time.

Next, a modification of the first embodiment will be described with reference to FIGS. As shown in FIG. 10, in this reading device, the stop sensor 111 is only omitted, and other configurations are the same. And FIG.
1 is A4 after detecting the document size by prescan
An example of reading a document of a size is shown.

In FIG. 11, the operation during the prescan in the sections A to C is the same as the operation shown in FIG. When the DC motor 103 starts reverse rotation, the up / down counter 113 starts down counting based on the rotation direction signal CW / CWW * (c) from the DC motor 103 (section D), and the CPU 112 causes the up / down counter to operate. The count value of 113 is monitored, the speed of the DC motor 103 is reduced at a position on the front side of the preset home position, and the ON / OFF signal (b) is generated when the shield plate 108 blocks the optical path of the home position sensor 107. Is set to "L" and the first carriage 104 is stopped (section E).

Next, when the CPU again sets both the on / off signal (b) and the rotation direction control signal F / b * (c) to "H", the DC motor 103 rotates in the normal direction and the first
The carriage 104 moves forward, and the up / down counter 11
3 counts up. Then, the original is read and the read data is written in the memory unit 158 (section F). The CPU 112 monitors the count value of the up / down counter 113, and when the reading of the A4 size document is completed, the rotation direction control signal F / b * (c) is set to “L” to retract the first carriage 104 ( In the sections G and H), the speed of the DC motor 103 is reduced at a position on the front side of the preset home position, and when the shielding plate 108 blocks the optical path of the home position sensor 107, the on / off signal (b) is set to " L ”(section I).

Therefore, in this case, the first carriage 10 is determined by the count value of the up / down counter 113.
Since the current position of No. 4 is monitored, the stop sensor 111
Can be omitted.

FIG. 12 is an overall configuration diagram showing a second embodiment of the document reading section.

Image sensor 200 composed of CCD or the like
Outputs an analog image signal by reading a document image and converting it into an electric signal.

The A / D converter 201 binarizes the analog image signal with a predetermined threshold value and outputs the digital image signal to the color masking section 202. The undercolor removal unit 203 removes the gray component in the RGB three-color signal from the color masking unit 202 and replaces it with a black signal, and then the gradation correction unit 204 performs γ conversion, brightness / darkness, contrast, density conversion, etc. Gradation processing is performed. The image modulator 205 performs various kinds of image processing based on the area signal generated by the area generation circuit 209, and the enlarging / reducing unit 206 performs enlarging / reducing scaling processing and outputs via the image interface (I / F) 207. To do.

The original detecting section 208 judges whether or not the original image is present in the area signal generated by the area generating circuit 209 in the signal processed by the gradation correcting section 204.
The judgment result is stored. These circuits 200 to 209 are also connected to the system bus 210.
It is controlled by the CPU 211 via 10. CPU2
The control program of 11 is stored in the ROM 213 in advance,
The RAM 212 is used as a work area for the CPU 211. The operation unit 214 can be set by combining the reading conditions (density, magnification, etc.) of the image sensor 200, and can be transmitted to the operator by displaying a message regarding the state and setting of the apparatus.

Therefore, as shown in FIG. 13, the document detecting section 208 has a tint judging section 20 for detecting only a specific tint.
81 and a pattern determination unit 2 that detects only a specific pattern
The AND circuit 2083 outputs the determination signal 2084 when both determination units 2081 and 2082 simultaneously detect the tint of the special color or the specific pattern. In addition to the determination signal 2084, the counter unit 2085 uses the area generation circuit
9 (FIG. 12) generated area signal 2086, line synchronization signal Line SYNC, and video clock signal VIDEO CLK
The maximum and minimum values of the XY coordinates based on the
It stores in 87.

Next, referring to FIG. 14, the tint determination unit 208
1 will be described in detail. In the registers 1303 to 1305, the CPU 211 sets respective values, which are stored in advance in the ROM 213 (FIG. 12) and indicate the R, G, and B tints of the pattern formed on the surface of the original plate. Comparators 1300 to 1302 respectively register 1303 to
The value set in 1305 is compared with the R, G, and B input image signals, and when all match, the AND circuit 1306 outputs a tint determination signal 1307.

Next, the pattern determination unit 2082 will be described in detail with reference to FIG. That is, m × n to be discriminated
The pixel pattern is stored in the ROM 404 in advance as a bit pattern. The binarization unit 400 binarizes an input image signal of R, G, and B, for example, 5 bits each with a certain threshold,
The preprocessing unit 401 performs preprocessing such as dust removal on the binarized data. The line buffer 402 has a capacity to store image data of m lines, and the pattern matching processing unit 403 stores m × n patterns stored in the ROM 404 and m × n cut out from the image in the line buffer 402. The above patterns are compared for each pixel. When the number of matching pixels is equal to or larger than a certain value preset in the register 406, the determination signal 407 of the specific pattern is A
It is output from the ND circuit 405.

Therefore, according to the above-described embodiment, the surface of the pressure plate 501 for pressing the original is formed in a specific color and in a specific pattern, and the surface of the pressure plate 501 not hidden by the original is used as the tint determination unit 2081. Since the pattern determination unit 2082 makes the determination, the size of the document can be accurately detected. An apparatus for feeding a plurality of originals one by one onto the reading surface is known, but according to the present embodiment, the original size can be detected regardless of the shape of the original pressing member of the apparatus. You can

As a modification of the second embodiment, as shown in FIG. 16, a micro switch 4 for detecting the opening / closing of the pressure plate 451 for pressing the document on the reading surface.
By attaching 50, the CPU 211 can detect opening / closing of the pressure plate 451 by the output signal of the microswitch 450.

Referring to FIG. 17, the CPU 211 in this case
The operation of will be described. First, the open / closed state of the pressure plate 451 is checked (step S1). If the pressure plate 451 is closed, the document detection operation is performed (step S2). If the document is discriminated, the measured value is registered as the document size (step S3). , S
4). If the original is not identified, an error message is displayed on the operation unit (step S5). If the pressure plate 451 is open in step S1, the document size determination operation is prohibited and the maximum readable size is registered as the document size (step S6). Therefore, for example, it is possible to detect the document size by prescanning, control the reading width of the scanner, and automatically select the size of the transfer paper.

[0057]

As described above, according to the present invention, a scanning body for optically scanning a document, a motor for driving the scanning body, and a pulse generating means for generating a pulse at every predetermined rotation angle of the motor. In an image reading apparatus including: a detection unit that detects the rotation direction of the motor; and a counter unit that counts up or down the number of pulses generated by the pulse generation unit according to the rotation direction detected by the detection unit. And the control means for controlling the position of the scanning body based on the count value of the counter means, the position of the scanning body can be constantly monitored by this count value. Therefore, even when the trimming process is performed, the reading operation of the trimming area can be performed immediately after returning to the front of the trimming area, and the document reading time can be shortened. Further, when the scanning body is returned to the home position after the operation of reading the original, it is possible to omit the sensor for obtaining the timing to start the braking of the motor as in the conventional case, and the manufacturing cost can be reduced.

The present invention also includes image reading means for optically reading an original and outputting an electrical image signal, specific pattern recording means for recording a specific pattern on the surface of the original pressing member for pressing the original, An image discriminating means for discriminating whether or not the specific pattern is included in the image signal read by the image reading means,
When the image determining unit determines that the specific pattern is included in the image signal, the image is determined to be an image obtained by reading the surface of the document pressing member. The size is detected, and thus the size of the original can be accurately detected.

Specifically, the image discriminating means discriminates whether or not the image data is a specific pattern in a unit of a fixed magnitude of the image signal, and / or presses the document from the image signal read by the image reading means. Since it is determined whether or not the pattern is the specific pattern by determining the tint of the attachment surface, the document size can be detected more accurately.

Further, the above effect can be easily realized by detecting the original area based on the discrimination result of the image discrimination means and the like.

Further, the present invention comprises a means for detecting whether or not the original pressing member is closed, and a prohibiting means for prohibiting the operation of the image discriminating means when the original pressing member is opened. Therefore, when the document pressing member is open, it is possible to control the reading width of the scanning body by performing other control such as registering the maximum readable size as the document size. .

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an outline of an embodiment of an image copying apparatus equipped with an image reading apparatus according to the present invention.

FIG. 2 is an overall configuration diagram of an image reading unit.

FIG. 3 is a block diagram showing a drive control system of a DC motor.

FIG. 4 is a block diagram of an image reading device.

5 is an explanatory diagram showing a compression operation of the encoder unit in FIG.

6 is a block diagram showing details of a memory unit of FIG. 4;

FIG. 7 is an explanatory diagram showing a processing result by the memory unit.

FIG. 8 is a timing chart for explaining the operation of the DC motor.

FIG. 9 is an explanatory diagram showing a trimming area of a document.

FIG. 10 is a configuration diagram of an image reading apparatus showing a modification of the first embodiment.

FIG. 11 is a timing chart for explaining the operation of the DC motor of the above modification.

FIG. 12 is a block diagram of a second embodiment.

FIG. 13 is a block diagram showing a document detection unit of a second embodiment.

FIG. 14 is a block diagram showing details of a tint determination unit.

FIG. 15 is a block diagram showing details of a pattern determination unit.

FIG. 16 is a perspective view showing a modification of the second embodiment.

FIG. 17 is a flow chart for explaining the operation of the CPU of the second embodiment.

FIG. 18 is a schematic diagram of an image reading apparatus for explaining a conventional example.

[Explanation of symbols]

 200 image sensor 501 pressure plate 2081 tint determination unit 2082 pattern determination unit 103 DC motor 104, 105 carriage 112, 211 CPU 113 up / down counter 151 CCD

Claims (6)

[Claims] 1. An image reading apparatus comprising a scanning body for optically scanning a document, a motor for driving the scanning body, and a pulse generating means for generating a pulse at each predetermined rotation angle of the motor, Detection means for detecting the rotation direction of the motor, counter means for up-counting or down-counting the number of pulses generated by the pulse generation means according to the rotation direction detected by the detection means, and a count value of the counter means An image reading apparatus comprising: a control unit that controls the position of the scanning body based on the image reading apparatus. 2. An image reading means for optically reading a document and outputting an electrical image signal, a specific pattern recording means for recording a specific pattern on the surface of a document pressing member for pressing the document, and the image reading. And an image discriminating unit that discriminates whether or not the specific pattern is included in the image signal read by the unit, and the image discriminating unit determines that the specific pattern is included in the image signal. In this case, it is determined that the image is an image obtained by reading the surface of the document pressing member. 3. The image reading apparatus according to claim 2, wherein the image discriminating means discriminates whether or not the image is a specific pattern in a unit of a fixed magnitude of the image signal. 4. The image discriminating means discriminates whether the pattern is a specific pattern or not by discriminating the tint of the document pressing surface from the image signal read by the image reading means. Alternatively, the image reading device according to claim 3. 5. The image reading apparatus according to claim 2, wherein the original area is detected based on the determination result of the image determining means. 6. A means for detecting whether or not the original pressing member is closed, and a prohibiting means for prohibiting the operation of the image discriminating means when the original pressing member is open. Claim 2 thru | or 5 characterized by the above-mentioned.
The image reading device according to any one of 1.