JP2002247299A - Image reading device - Google Patents

Abstract

(57) Abstract: The present invention provides an image reading apparatus such as an image scanner or a digital copying machine that appropriately sets an image reading position by using a sheet-through reading method. A color image reading apparatus has a lamp and an optical system mounted on a running body, irradiates a document conveyed to a reading position by an ARDF with light from the lamp, and optically reflects light reflected from the document. When reading the image of the original by introducing the same into the CCD drive unit 9, the original having a uniform density is conveyed from the ARDF 20 as an adjustment original, and the adjustment original is irradiated with light from the lamp 4 on the traveling body. Then, the reflected light from the adjustment document is introduced into the CCD driving unit 9 by an optical system on the traveling body, and the appropriate position of the traveling body is calculated based on the density data output from the CCD driving unit 9 to perform the reference reading. Set as position. Therefore, it is possible to appropriately correct the variation between the devices generated from the individual components of the color image reading device 1, and to read a stable image with high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image reading apparatus, and more particularly, to an image reading apparatus such as an image scanner or a digital copying machine that appropriately sets an image reading position by using a sheet-through reading method.

[0002]

2. Description of the Related Art In an image forming apparatus such as an image scanner or a digital copying machine, an optical system for reading an image of a document is fixed, and a sheet-through type ADF (automatic document feeder) for reading the image of the document while moving the document. ) Is often used.

On the other hand, the ADF of the belt type transports an original on a contact glass (set with the original spread downward and set) of the image input / output device main body, stops the original, and moves the optical system while moving the optical system. Read the image.

[0004] The sheet-through system is simpler in structure than the belt system and has advantages in cost.

[0005]

However, in such a conventional image reading apparatus, if a sheet-through type ADF is adopted, the image is read while moving the original, and the image is read depending on the behavior of the original. Is affected. In order to stabilize the behavior of this document, it is desirable to perform linear conveyance with a slow moving speed of the document and no speed fluctuation. However, in particular, realizing linear conveyance requires a large space as an image input / output device. Therefore, in most cases, the original makes a U-turn from the paper feeding direction and enters the reading unit at a predetermined angle, and after reading, the document is transported so that the original is peeled off from the reading unit.

That is, the original is placed on the reading glass
Is conveyed in the shape of a letter, and the lowest point is on the glass surface. Ideally, the reading when the ADF is used is performed when the reading glass is in contact with the reading glass. However, the position may vary depending on the paper type, the variation in the position of the ADF and the image reading apparatus main body, or the displacement of the optical system. It will fluctuate depending on the machine and usage environment.
It adversely affects image characteristics.

Therefore, according to the present invention, a light source and an optical system are mounted on a traveling body, and the light source irradiates light to a document conveyed to a reading position by an automatic document conveying mechanism.
The reflected light from the original is introduced into the photoelectric element by an optical system,
When reading an image on a document, the automatic document feeder transports a document of uniform density throughout as an adjustment document, irradiates the adjustment document with light from a light source on the traveling body, and reflects light from the adjustment document. Light is introduced into the photoelectric element by the optical system on the traveling body, and based on density data output from the photoelectric element,
By calculating the proper position of the traveling body and setting it as the reference reading position, it is possible to appropriately correct variations between the devices generated from individual components of the image reading device and read a stable image with high quality. It is an object to provide an image reading device.

According to a second aspect of the present invention, a normal document having a margin is conveyed as an adjustment document, a blank portion of the document is read, an appropriate position of the traveling body is calculated, and the reference position is set as a reference reading position. This makes it possible to appropriately compensate for variations among devices caused by individual components of the image reading device without preparing a special document that is expensive and difficult to obtain as an adjustment document, and achieve a stable image. It is an object of the present invention to provide an image reading apparatus capable of reading quality and at low cost.

According to a third aspect of the present invention, a plurality of adjusted originals are transported from the automatic original transport mechanism to a reading position, and an appropriate position of the traveling body is determined based on density data obtained when the plurality of adjusted originals are read. By calculating and setting as a reference reading position, repeated reading calculation cancels image noise that is likely to occur at the time of reading, and sets as a reference reading position with higher accuracy, and a more stable image. It is an object of the present invention to provide an image reading device capable of obtaining the image reading device.

[0010]

According to the first aspect of the present invention, there is provided an image reading apparatus having a light source and an optical system mounted on a traveling body, and a light conveyed from the light source to a document conveyed to a reading position by an automatic document conveying mechanism. And the reflected light from the original is introduced into the photoelectric element by the optical system to read the image of the original. In the image reading apparatus, the original having a uniform density is adjusted from the automatic original transport mechanism. The document is conveyed as a document, the adjustment document is irradiated with light from the light source on the traveling body, and the reflected light from the adjustment document is introduced into the photoelectric element by the optical system on the traveling body. The above object is achieved by calculating an appropriate position of the traveling body based on density data output from the element and setting the calculated position as a reference reading position.

According to the above arrangement, the light source and the optical system are mounted on the traveling body, and the original conveyed to the reading position by the automatic original conveying mechanism is irradiated with light from the light source, and reflected light from the original is transmitted. When reading the image of the original by introducing it to the photoelectric element by the optical system, the original with the uniform density is transported as an adjusted original from the automatic original transport mechanism, and light is emitted from the light source on the traveling body to the adjusted original. Irradiates the reflected light from the adjusted document into the photoelectric element by an optical system on the traveling body, calculates an appropriate position of the traveling body based on density data output from the photoelectric element, and calculates a reference reading position. Since the setting is made as described above, it is possible to appropriately correct the variation between the devices generated from the individual components of the image reading device, and to read a stable image with high quality.

In this case, for example, as described in claim 2, the image reading device conveys a normal document having a margin as the adjustment document, reads a margin portion of the document, and reads the margin of the document. An appropriate position may be calculated and set as a reference reading position.

According to the above arrangement, a normal original having a margin is conveyed as an adjustment original, the margin of the original is read, an appropriate position of the traveling body is calculated and set as a reference reading position. It is possible to appropriately compensate for variations between devices caused by individual components of the image reading device without preparing a special document which is expensive and difficult to obtain as a document. It can be read in quality and at low cost.

In addition, for example, the image reading device conveys the plurality of adjusted documents from the automatic document feed mechanism to the reading position and reads the plurality of adjusted documents. The appropriate position of the traveling body may be calculated based on the density data at that time, and may be set as the reference reading position.

According to the above configuration, the plurality of adjusted originals are transported from the automatic original transport mechanism to the reading position, and the proper position of the traveling body is calculated based on the density data obtained when the plurality of adjusted originals are read. Therefore, since it is set as the reference reading position, it is possible to cancel image noise that is likely to occur at the time of reading by repeatedly performing the reading operation,
An even more stable reference image can be set to obtain a more stable image.

[0016]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIGS. 1 to 9 show an embodiment of the image reading apparatus of the present invention. FIG. 1 shows a sheet-through type document to which the embodiment of the image reading apparatus of the present invention is applied. FIG. 2 is a schematic front view of a color image reading apparatus 1 including a feeder.

In FIG. 1, a color image reading apparatus 1 comprises:
A contact glass 3 is disposed on an upper surface of the main body housing 2. Inside the main body housing 2 below the contact glass 3, a lamp 4 as a light source and a first mirror 5, a second mirror 6 and a second mirror 6 are provided. 3 mirror 7, lens 8, CCD drive unit (S
BU) 9, a traveling body motor 10, a system control unit 11, and the like.

The lamp 4 and the first mirror 5 are mounted on a first traveling body (not shown), and the second mirror 6 and the third mirror 7 are mounted on a second traveling body (not shown). Is moved in the sub-scanning direction.

When reading the original P (see FIGS. 5 and 6) set on the contact glass 3, the color image reading apparatus 1 moves the first traveling body and the second traveling body in the sub-scanning direction. Meanwhile, light is emitted from the lamp 4 to the document P set on the contact glass 3, the light reflected by the document P is reflected by the first mirror 5 in the direction of the second mirror 6, and further, by the second mirror 6. The light is reflected in the direction of the third mirror 7 and is reflected in the direction of the lens 8 by the third mirror 7. The color image reading device 1 condenses the light incident on the lens 8 to the CCD drive unit 9, and photoelectrically converts the incident light by a color CCD (Charge Coupled Device) mounted on the CCD drive unit 9. Outputs an image signal.

Further, the color image reading apparatus 1 is provided with a white reference plate (not shown) outside the document area, and reads the white reference plate prior to reading the document P, and includes optical system distortion information. Collect and save shading data.

The color image reading apparatus 1 has an ARDF (automatic double-sided document feeder) 20 mounted on the upper portion of the main body 2. The ARDF 20 includes a document table 21, a call roller 22, a paper feed belt 23, and a transport roller. 24, separation roller 2
5, a first conveyance roller 26, a reflection guide plate 27, a second conveyance roller 28, a discharge roller 29, a reversing roller 30, a branching claw 31, a reversing table 32, and the like. Detection board 34, first original length sensor 35, second original length sensor 36, and original platen 21
A set sensor 37 and the like for detecting whether or not the document P is set in the
The paper feed mechanism of the paper feed belt 23, the transport roller 24, and the separation roller 25 is driven by a paper feed motor (not shown), and a first transport roller 26, a reflection guide plate 27, a second transport roller 28,
The transport mechanism of the discharge roller 29 and the reversing roller 30 is driven by a transport motor (not shown).

An DF original glass 38 is provided at an upper portion of the main body 2 and at a position facing the reflection guide plate 27.

When reading the original P by transporting the original P using the ARDF 20, the color image reading apparatus 1 converts the original P stacked along the original guide 21 a of the original platen 21 into a single-sided original. If reading is selected,
Conveying roller 2 by the call roller 22 and the paper feed belt 23
4. The document P is transported by the separation roller 25 and the first transport roller 26 to the second transport roller 28 and the paper discharge roller 29 via the reading position between the DF document glass 38 and the reflection guide plate 27, and the document P is transferred. Discharge.

When double-sided original reading is selected, the color image reading apparatus 1 first reads the front side of the original P as described above, and performs the same operation as when single-sided original reading is selected. I do.

That is, the DF document glass 38 and the reflection guide plate 27 are driven by the feeding roller 22, the transport roller 24 by the paper feed belt 23, the separation roller 25, and the first transport roller 26.
The document is fed to the second transport roller 28 and the paper discharge roller 29 through the reading position between and the branch claw 31 is switched downward without discharging the document P, and is transferred onto the reversing table 32 by the reversing roller 30. I do.

The color image reading apparatus 1 switches the branch pawl 31 upward after the trailing end of the document P has passed through the paper discharge roller 29, temporarily stops the reversing roller 30, and then moves the reversing roller 30 to the above-described state. The document P is transported from the reversing table 32 toward the first transport roller 26 by rotating the document P in the opposite direction. The color image reading device 1 further includes a DF original glass
The document P is conveyed to a second conveyance roller 28 and a discharge roller 29 via a reading position between the document P and the reflection guide plate 27, and then the document P is discharged.

In the color image reading apparatus 1, when the document P passes through the reading position between the DF document glass 38 and the reflection guide plate 27 in reading both the front surface and the back surface, the document P is positioned near the reading position. The document P is irradiated by the moving lamp 4, and the reflected light is reflected by the first mirror 5, the second mirror 6, and the third mirror 7, and is reflected by the lens 8.
The light is condensed on the color CCD 9a (see FIG. 3) of the CD drive unit 9 and photoelectrically converted into RGB by the color CCD 9a.
Further, the color image reading device 1 reads the white reference plate and collects and saves the shading data in the same manner as the reading of the document P on the contact glass 3 before the first document P is conveyed. As a white reference plate,
A dedicated white reference plate may be provided at a predetermined reference position,
The reflection guide plate 27 may be used as a white reference plate.

As shown in FIG. 2 which is an overall block diagram of the color image reading device 1 and FIG. 3 which is a data flow diagram of the image data of the color image reading device 1, the color image reading device 1 Main body of device 1 and AR
SCU 41, VIOB 42, ADU 43, OIPU 4 for controlling the operation of the color image reading apparatus 1 including the DF 20
4, a NIC 45, an ISIC 46, a PSU (power supply unit) 47, a power switch 48, a plug 49, a scanner motor 50, and the like.

The color image reading device 1 converts the reflected light of the document P, which has entered the color CCD 9a on the CCD drive unit 9, into analog signals of RGB colors having voltage values corresponding to the light intensity in the color CCD 9a. Then, the analog signal of each color of RGB is divided into odd bits and even bits and VIO
Output to B42. The analog image signal of the CCD drive unit 9 is supplied to the analog processing circuit 42a on the VIOB 42.
After the dark potential portion is removed, the odd bits and the even bits are combined, and the gain is adjusted to a predetermined amplitude.
The signal is input to the / D converter 42b and converted into a digital signal. The image signal digitized by the A / D converter 42b is subjected to shading correction by the shading ASIC 42c, and the image signal is converted from the VIOB 42 to the RI on the SCU 41.
After image processing such as gamma correction and MTF correction is performed by the PU 41a, the PU 41a outputs a video signal together with a synchronization signal and an image clock. Here, the shading correction is performed by correction data calculated from the shading data stored in the memory of the shading ASIC 42c.

The video signal output from the RIPU 41a is output to the OIPU 44. The OIPU 44 performs predetermined image processing on the input video signal, and again executes the SCU.
Output to 41.

The video signal input to the SCU 41 is V
The input to the IDEO input switching circuit 41b is input to the other input of the VIDEO input switching circuit 41b.
The video signal is input from a, and the OIPU 44 can select whether or not to perform image processing.

The video signal output from the VIDEO input switching circuit 41b is input to a memory control LSI (SIBC2) 41c that manages an image data storage unit (SDRAM), and is stored in an image memory composed of an SDRAM. The image data stored in the image memory is sent to the SCSI controller 41d, and is transferred to an external device such as a personal computer or a printer via the SCSI-I / F.

On the SCU 41, a CPU 60 (see FIG. 4), a ROM (not shown), and a RAM (not shown) are mounted.
By controlling d, communication with an external device such as a personal computer is performed by the SCSI-I / F. In addition, the CPU 60
The video signal output from the O input switching circuit 41b is
An IEEE 1394-I / F via an ISIC 46 which is an IEEE 1394 controller, and a network-I / F via an NIC 45 which is a network scanner controller.
Communication with an external device such as a personal computer or a printer is performed by F. Further, the CPU 60 also controls the timing of the traveling body motor 10, which is a stepping motor of the scanner main body, the sheet feeding motor of the ARDF 20, and the transport motor.

The ADU 43 has a function of relaying power supply of electrical components used for the ARDF 20. SCU4
1, the input port connected to the CPU 60 is VI
It is connected to an operation panel (SOP) 50 of the main body of the color image reading apparatus 1 via the OB 42. Operation panel (SO
Although not shown, a start switch and an abort switch are mounted on P) 50. When each switch is pressed, the CP of the SCU 41 is input via the input port.
U60 detects that the switch has been turned on.

FIG. 4 is a block diagram related to the image reading process of the color image reading apparatus 1, and the image processing L
By outputting LSYNC (main scanning line synchronization signal) and LGATE (main scanning line data output period) from the RIPU 41a, which is the SI, to the SBU 9, which is the CCD driving unit, image data is output from the SBU 9. The flow of the image data is as follows: SBU9 → RIPU41a → memory control LSI (SIBC2) 41c → SCSI controller 41d → external (such as a personal computer). Also, C
Image processing LSI for ON / OFF of image output from PU60
(RIPU) 41a is provided as a known technique inside, and is controlled by rewriting an internal register.

An interrupt signal from the memory control LSI 41c (this interrupt is generated when the memory state is full, near full, or empty, and is a register provided as a known technology inside the memory control LSI (SIBC2) 41c, not shown). The state can be distinguished)
It is configured to input 0. The CPU 60 also controls the motor of the traveling body motor 10 for moving the traveling body.

Next, the operation of the present embodiment will be described. In the color image reading apparatus 1, the document P is
Although it is sent upward, its transport trajectory is U-shaped, as shown in FIGS. Depending on the angle at which the document P enters the reading unit or the angle at which the document P is discharged, the distance between the DF document glass 38 and the document P greatly changes as shown in FIG. The document P to be read needs to be at a certain distance from the DF document glass 38 in order to be in the stable area as an image.
The portion in contact with the DF document glass 38, that is, the portion of the document stable area in FIG. 5 is optimal, and it is necessary to read the document P in the range of the document stable area. On the other hand, D
If the document P is not in close contact with the document glass 38 for F, the behavior of the document P is not constant, so that the variation of the read data increases,
This affects the quality of the read image. Therefore, in general, in the color image reading apparatus, the initial reading position is set aiming at the center of the glass contact area. However, due to a mounting error between the ARDF 20 and the main body of the color image reading apparatus 1, an optical axis shift of the optical system, and the like. However, the stable area does not always come at the initial reading position.

Therefore, in the color image reading apparatus 1 of the present embodiment, as shown in FIG. 7, a document (adjustment document) P having a constant density is set on the document table 21 and reading is performed (C).
CD101). The shading data is collected (step S102), the traveling body is returned to the initial reading position (step S103), and conveyance of the document P is started (step S1).
04), it moves to the adjusted read data measurement position + Pn (step S105). And the color image reading device 1
The P + n point data is measured (step S106), the point number n is decremented by "1" (n = n-1) (step S107), and it is checked whether it is within the reading area (step S108). When the color image reading apparatus 1 is not within the reading area, the process proceeds to ΔPmin calculation processing (step S109), and when it is within the reading area, it is checked whether there is any remaining point (step S110). Step S
If there are remaining points in step 110, the color image reading apparatus 1 returns to step S105 and performs the same processing as described above.
A Pmin calculation process is performed (step S111), and the read adjustment position P0 'is determined (step S112).

Here, the center of the initial reading position is defined as "P0: initial value", and the position of the reading range in the + direction (sub-scanning direction +, direction of the contact glass 3) from the position of P0 is defined as +.
Pn, + Pn-1 and + Pn-2 at positions slightly shifted in the 0 direction
… Beyond + P1, P0, the-direction (sub-scanning direction, opposite to the direction of the contact glass 3) is -P1, P-2, P- (n-
1), P-n. Note that -Pn is in the reading area like +.

Each position between -Pn and + Pn is determined by a feedback method such as the number of input drive pulses and a brush motor with an encoder when performing open loop control of a step motor or the like from a reference position (or an adjacent point). If there is, it can be managed by the number of encoder pulses.

Then, the color image reading apparatus 1 has a function of + Pn
Then, the first traveling body on which the lamp 4 and the first mirror 5 are mounted is stopped, and scanning is performed on the moving original P by scanning several lines to several tens of lines. The number of main scan data in this case is arbitrary. Next, first to the position of + Pn-1
The traveling body is moved, and the same data is read similarly. The process is repeatedly performed sequentially, and the process is performed up to the position P-n beyond P0. After the implementation, the first traveling body is returned to the initial reference point, and the operation waits.

The color image reading apparatus 1 performs shading correction on the data of the document P read at each position between P + n and P-n in accordance with the flow of the data image described above, and directly changes the data inside the shedding ASIC 42c. It is stored in a memory (not shown). Note that the main scanning direction, the number of line data in the sub-scanning, the number of stop points, and the stop intervals can be appropriately changed by this memory capacity, and the measurement accuracy increases as the number of data increases.

The CPU 60 reads this data from the shedding ASIC 42c, and compares the data displacement amount (for example, min-max difference) at each stop point. In this case, the point where the data displacement is the least is where the document P is stable in the sub-scanning direction.

For example, assuming that the max-min difference of the data output (full range 12 bits = 4096 digits) when passing through the white document P is ΔPn, the minimum Δ
When searching for Pmin, (unit digit) ΔPn = 300 (max: 3960, min: 366)
0) ΔPn-1 = 280 (max: 3960, min: 368)
0). . ΔP2 = 100 (max: 3960, min: 386)
0) ΔP1 = 50 (max: 3960, min: 3910) ΔP0 = 80 (max: 3960, min: 3880) ΔP-1 = 130 (max: 3960, min: 383)
0). . . ΔP-n = 400 (max: 3960, min: 356)
0), the minimum ΔPmin = ΔP1 is selected.

Therefore, P1 becomes the best point, and the CPU 60 calculates the necessary distance from P0, and sets this as the reading position P0 'when the next ADF is used, and the position data of P1 is stored in P0' as an SRAM (shown in FIG. )).

In this case, the length of the adjustment document P may be any length as long as measurement is possible during this time. Even if the adjustment document P is short, it can be dealt with by reducing the document feeding speed. it can. The adjusted original P has a uniform density,
Use a material that can withstand the conveyance in F20, for example, a material that is not easily scratched or peeled. As an example of the uniform density document P, for example, there is a document uniformly printed like a Kodak gray scale chart. There is no problem if the brightness of the chart to be used is within the input range in order to obtain the difference between the reflected light from the uniform original P density. Is easy to do. If the reflectance of the document P is larger than necessary, the output of the CCD may reach the saturation voltage and go out of the input range.

Further, the adjustment document P can be a blank portion of a normal character document (such as an office document). That is, as shown in FIG. 8, most ordinary text originals have a margin of several millimeters near four sides of a rectangle (up, down, left, and right of paper). If the scanner can detect the paper passing size and the feeding direction or can be input as information, and if there is a continuous density uniform blank space in the sub-scanning direction to some extent, the above adjustment measurement can be realized with a substitute document.

Therefore, the adjustment can be made not only at the time of factory shipment adjustment using a special original, but also at the user level. For example, when passing documents of different paper types for each scan job,
By passing only the first sheet in the adjustment mode, a good image can be obtained each time.

When the ARDF 20 can mount a plurality of originals P, the CPU 60 prepares an original P to be read as a normal image next to the adjusted original, and the CPU 60 detects the second original P at the time of detection. Then, referring to the position of P0 'in the SRAM, the motor is driven to move the carriage to P0', thereby enabling continuous reading.

In the margin reading, the main scanning data is taken in by 4 to 5 mm from the end of the original P (for 600 dpi,
95-120 dots), data is collected during that period, and the above-described calculation is performed to determine an appropriate position. Since the ARDF 20 is used, dust (paper dust, toner of an output document such as PPC) in the ARDF 20 may be carried to the adjustment document P during adjustment and measured. When dust is detected, an abnormal value exceeding the data variation due to the original paper behavior is detected, which affects the result. In addition, the number of data samples is desired to be large because the paper flaps depending on the measurement location. In order to increase the measurement accuracy, it is effective to increase the number of samples at the time of adjustment and the number of samples. In addition, since paper dust is difficult to generate depending on the type of paper, if the white paper is not PPC-printed, it is possible to clean dust on the transport path by increasing the number of times of paper passing. The reliability of the detection data can be improved as the number is increased.

When a plurality of adjusted originals are used, processing is performed as shown in FIG. In the description of FIG. 9, the same processing steps as those in FIG. 7 are assigned the same step numbers, and descriptions thereof are omitted.

The color image reading apparatus 1 shown in FIG.
If there are no remaining points in step S110 for one adjusted document, the count value m of the counter for counting the number of remaining document feeds is decremented by "1" (step S201), and the remaining document number m is checked. A check is made (whether m = 0) (step S202).

If it is determined in step S202 that the number of remaining documents m is not "0", the color image reading apparatus 1 returns to step S105 and performs the same processing as described above.
At 202, when the number of remaining documents m becomes “0”, ΔPmin calculation processing is performed (step S111), and the reading adjustment position P
0 ′ is determined (step S112).

As described above, according to the color image reading apparatus 1 of the present embodiment, the lamp 4 and the first mirror 5
The optical system of the fourth mirror 8 is mounted, and the original P conveyed to the reading position by the ARDF (automatic double-sided original conveying device) 20 is irradiated with light from the lamp 4 to reflect light from the original P In order to read the image of the document P by introducing it into the CCD drive unit (SBU) 9, the document P having a uniform density as a whole is transported from the ARDF 20 as an adjustment document, and the adjustment document is fed to the ramp 4 From the adjustment document, and the reflected light from the adjustment document is
The appropriate position of the traveling body is calculated based on the density data output from the CCD driving unit 9 and is set as a reference reading position.

Therefore, it is possible to appropriately correct variations between the devices generated from the individual components of the color image reading device 1, and to read a stable image with high quality.

Further, the color image reading apparatus 1 of the present embodiment conveys a normal document P having a margin as an adjustment document, reads a margin portion of the document P, calculates an appropriate position of the traveling body, This is set as the reference reading position.

Therefore, the price of the adjustment original is high,
It is possible to appropriately correct variations between devices generated from individual components of the color image reading device 1 without preparing a special document that is difficult to obtain, and to obtain a stable image with high quality at a low cost. Can be read.

Further, a plurality of adjustment originals P are
To the reading position, calculate the appropriate position of the traveling body based on the density data when the plurality of adjusted originals are read, and set it as the reference reading position. It is also possible to cancel image noise that is likely to occur, and to set a more accurate reference reading position to obtain a more stable image.

Although the invention made by the inventor has been specifically described based on the preferred embodiments, the invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

[0061]

According to the image reading apparatus of the present invention, the light source and the optical system are mounted on the traveling body, and the light source irradiates the document conveyed to the reading position by the automatic document conveying mechanism. Then, when the reflected light from the original is introduced into the photoelectric element by an optical system and an image of the original is read, the original having a uniform density is transported from the automatic original transport mechanism as an adjusted original, and the adjustment is performed. The original is irradiated with light from a light source on the traveling body, reflected light from the adjusted original is introduced into the photoelectric element by the optical system on the traveling body, and the density of the traveling body is determined based on density data output from the photoelectric element. Since the proper position is calculated and set as the reference reading position, it is possible to appropriately correct the variation between the devices generated from the individual components of the image reading device and read a stable image with high quality.

According to the image reading apparatus of the present invention, a normal original having a margin is conveyed as an adjustment original, the margin of the original is read, and an appropriate position of the traveling body is calculated. Since the setting is made as the reading position, it is necessary to appropriately correct the variation between the devices caused by individual components of the image reading device without preparing a special document which is expensive and difficult to obtain as an adjustment document. It is possible to read a stable image with high quality and at low cost.

According to the image reading apparatus of the third aspect of the present invention, a plurality of adjusted originals are transported from the automatic original transport mechanism to the reading position, and based on the density data obtained when the plurality of adjusted originals are read. Since the proper position of the traveling body is calculated and set as the reference reading position, image noise that is likely to occur at the time of reading can be canceled by repeatedly performing the reading operation, and the reference reading position with higher accuracy is set. Thus, a more stable image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a color image reading apparatus to which an embodiment of the image reading apparatus of the present invention is applied.

FIG. 2 is an overall block configuration diagram of the color image reading apparatus of FIG. 1;

FIG. 3 is a data flow diagram of the color image reading apparatus of FIG. 1;

FIG. 4 is a block diagram of a reading processing unit of the color image reading apparatus of FIG. 1;

FIG. 5 is a front view showing a state of a document on a DF document glass portion of the color image reading apparatus of FIG. 1;

FIG. 6 is a diagram showing a relationship before and after adjustment of a document reading position at a DF document glass position in FIG. 5;

FIG. 7 is a flowchart showing a reading position adjustment process by the color image reading apparatus of FIG. 1;

FIG. 8 is a conceptual diagram when a normal text document is used as an adjustment document.

FIG. 9 is a flowchart showing a reading position adjustment process when a plurality of adjustment originals are used by the color image reading apparatus of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 color image reading device 2 main body housing 3 contact glass 4 lamp 5 first mirror 6 second mirror 7 third mirror 8 lens 9 CCD drive unit (SBU) 10 traveling motor 11 system control unit 20 ARDF 21 platen 22 call Roller 23 Paper feed belt 24 Transport roller 25 Separation roller 26 First transport roller 27 Reflection guide plate 28 Second transport roller 29 Discharge roller 30 Reverse roller 31 Branch claw 32 Reverse table 38 DF original glass 41 SCU 41a RIPU 41b VIDEO input Switching circuit 41c Memory control LSI (SIBC2) 41d SCSI controller 42b A / D converter 42c Shading ASIC 42 VIOB 43 ADU 44 OIPU 45 NIC 46 IIC 47 PSU (power supply Knit) 48 power switch 49 plug 50 scanner motor 60 CPU

Claims (3)

[Claims] A light source and an optical system are mounted on a traveling body, and light from the light source is irradiated on a document conveyed to a reading position by an automatic document conveying mechanism, and reflected light from the document is reflected by the optical system. In the image reading apparatus which reads the image of the original by introducing the photoelectric element, the original having a uniform density is transported as an adjusted original from the automatic original transport mechanism, and the adjusted original on the traveling body is transferred to the adjusted original. Light is emitted from a light source, and reflected light from the adjustment document is introduced into the photoelectric element by the optical system on the traveling body, and based on density data output from the photoelectric element, an appropriate position of the traveling body is determined. An image reading apparatus that calculates the reference reading position and sets the reference reading position. 2. The image reading apparatus according to claim 1, wherein the image reading device conveys a normal document having a margin as the adjustment document, reads a margin portion of the document, calculates an appropriate position of the traveling body, and sets the reference position as a reference reading position. The image reading apparatus according to claim 1, wherein 3. The image reading device according to claim 1, wherein the plurality of adjusted originals are transported from the automatic original transport mechanism to the reading position.
The image according to claim 1, wherein an appropriate position of the traveling body is calculated based on the density data obtained when the plurality of adjustment documents are read, and the calculated position is set as the reference reading position. Reader.