JP3977019B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  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 uses a sheet-through reading method to appropriately set an image reading position.
[0002]
[Prior art]
  2. Description of the Related Art Image forming apparatuses such as image scanners and digital copying machines use a sheet-through ADF (automatic document feeder) that fixes an optical system that reads an image of a document and reads the image of the document while moving the document. There are many things.
[0003]
  On the other hand, the belt type ADF conveys a document on a contact glass (a document is spread and set downward) of the image input / output device body, reads the image of the document while stopping the document and moving the optical system. .
[0004]
  The seat-through method has a simpler structure than the belt method, and has an advantage in terms of cost.
[0005]
[Problems to be solved by the invention]
  However, in such a conventional image reading apparatus, when the sheet-through ADF is adopted, the image is read while moving the document, and therefore the image depends on the behavior of the document. In order to stabilize the behavior of the original, it is desirable to perform linear conveyance with a low movement speed and no fluctuation of the original. In particular, when linear conveyance is realized, a large space is occupied as an image input / output device. Therefore, in most cases, the original is U-turned from the paper feeding direction and is incident on the reading unit at a predetermined angle, and discharge after reading is also transferred so as to peel off the original from the reading unit.
[0006]
  That is, the document is conveyed so as to draw a letter U on the reading glass, and the lowest point (the vertex of the letter U) comes into contact with the glass surface. Ideally, reading is performed when the ADF is used where the original is in contact with the reading glass. However, in reality, the position varies depending on the machine and usage environment due to the paper type, position variation between the ADF and the image reader main unit, optical system misalignment, etc. Adversely affects.
[0007]
  Therefore, the present invention provides an image reading apparatus without preparing a special document in reading a moving document using an ADF caused by a paper type, a position variation between the ADF and the image reading apparatus main body, a deviation of an optical system, and the like. The optimal reading proper position in the sub-scanning direction of the optical system is calculated, and a stable image is read with high quality.
[0008]
[Means for Solving the Problems]
  According to the first aspect of the present invention, the light source and the optical system are mounted on the traveling body, the light source is irradiated with light from the light source to the document transported to the reading position by the automatic document transport mechanism, and the reflected light from the document is In an image reading apparatus that is introduced into a photoelectric element by an optical system and reads an image of the document, the traveling body is sequentially moved by a predetermined interval in the sub-scanning direction and stopped, and the automatic document transport mechanism is stopped at each stop position. On the moveSaidThe original is irradiated with light from the light source on the traveling body, and reflected light from the original is reflected on the traveling body.SaidIntroduce into the photoelectric element by an optical system, read a blank portion of the document a predetermined line,SaidAt each stop positionOf the predetermined lineCalculate the amount of displacement of the read data, and at each stop positionSaidDisplacement of read dataThe position corresponding to the smallest displacement amount inAppropriate position of the traveling bodyAsAnd determining the appropriate position as a reading position of the moving document in the sub-scanning direction of the traveling body.
[0009]
  Also,Claim 2The described inventionClaim 1In the image reading apparatus described above, from the automatic document conveying mechanismA plurality of saidTransport the document,SaidAt each stop positionSaidThe amount of displacement of the read dataSaidIt is calculated from the read data of a plurality of documents.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. As long as there is no description which limits, it is not restricted to these aspects.
[0011]
  FIG. 1 is a schematic front view of a color image reading apparatus 1 having a sheet-through type document feeder to which an embodiment of the image reading apparatus of the present invention is applied. In FIG. 1, a color image reading apparatus 1 has a contact glass 3 disposed on an upper surface portion of a main body housing 2, and a lamp 4 as a light source is provided inside the main body housing 2 below the contact glass 3. A first mirror 5, a second mirror 6, a third mirror 7, a lens 8, a CCD drive unit (SBU) 9, a traveling body motor 10, a system control unit 11, and the like are disposed.
[0012]
  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). It is moved in the scanning direction.
[0013]
  When reading the document 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 while moving the lamp. 4 irradiates the original P set on the contact glass 3 with light, the light reflected by the original P is reflected by the first mirror 5 toward the second mirror 6, and the second mirror 6 further reflects the third mirror. The light is reflected in the seven directions and reflected in the direction of the lens 8 by the third mirror 7. The color image reading apparatus 1 condenses the light incident on the lens 8 on the CCD drive unit 9 and photoelectrically converts the incident light with a color CCD (Charge Coupled Device) mounted on the CCD drive unit 9. Output image signal.
[0014]
  Further, the color image reading apparatus 1 is provided with a white reference plate (not shown) outside the document area, reads the white reference plate prior to reading the document P, and obtains shading data including optical system distortion information. Collect and save.
[0015]
  In the color image reading apparatus 1, an ARDF (automatic duplex document feeder) 20 is attached to the upper part of the main body housing 2, and the ARDF 20 is composed of a document table 21, a calling roller 22, a sheet feeding belt 23, a conveying roller 24, a separation roller. A roller 25, a first conveyance roller 26, a reflection guide plate 27, a second conveyance roller 28, a paper discharge roller 29, a reversing roller 30, a branching claw 31, a reversing table 32, and the like, a document trailing edge sensor 33, a width A size detection board 34, a first document length sensor 35, a second document length sensor 36, a set sensor 37 for detecting whether or not the document P is set on the document table 21, and the like are provided. 22, 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), the first transport roller 26, the reflection guide plate 27, 2 transport rollers 28, driven by a conveying motor (not shown) the conveying mechanism of the sheet discharge roller 29 and the reverse roller 30.
[0016]
  A DF document glass 38 is disposed at an upper portion of the main body housing 2 and facing the reflection guide plate 27.
[0017]
  When the color image reading apparatus 1 conveys the original P using the ARDF 20 and reads the original P, the single-sided original reading is selected for the original P stacked along the original guide 21a of the original table 21. In this case, the calling roller 22, the feeding roller 24, the conveying roller 24, the separation roller 25, and the first conveying roller 26 pass through the reading position between the DF original glass 38 and the reflection guide plate 27. 2 The paper P is transported to the transport roller 28 and the paper discharge roller 29 and the original P is discharged.
[0018]
  Further, when double-sided original reading is selected, the color image reading apparatus 1 first reads the surface of the original P as described above, and performs the same operation as when single-sided original reading is selected.
[0019]
  That is, the calling roller 22, the sheet feeding belt 23 conveys the conveying roller 24, the separation roller 25, and the first conveying roller 26 passes through the reading position between the DF original glass 38 and the reflection guide plate 27, and the second conveying roller 28 and The paper is fed to the paper discharge roller 29 and the branch claw 31 is switched downward without being transferred to the original P, and is transferred onto the reverse table 32 by the reverse roller 30.
[0020]
  The color image reading apparatus 1 switches the branching claw 31 upward after the trailing edge of the document P passes through the paper discharge roller 29, temporarily stops the reverse roller 30, and then reverses the reverse roller 30 to the above. By rotating in the direction, the document P is transported from the reversing table 32 toward the first transport roller 26. The color image reading apparatus 1 further passes through the first conveyance roller 26 and the reading position between the DF original glass 38 and the reflection guide plate 27 in the same manner as the surface, and then passes through the second conveyance roller 28 and the discharge roller 29. Then, the original P is conveyed, and then the original P is discharged.
[0021]
  The color image reading apparatus 1 is moved to the vicinity of the reading position when the document P passes through the reading position between the DF document glass 38 and the reflection guide plate 27 in both reading of the front surface and the back surface. The original P is irradiated by the lamp 4 and the reflected light is reflected by the first mirror 5, the second mirror 6 and the third mirror 7, and is applied to the color CCD 9 a (see FIG. 3) of the CCD drive unit 9 by the lens 8. The light is condensed and photoelectrically converted into RGB by the color CCD 9a. The color image reading device 1 reads the white reference plate and collects and stores shading data in the same manner as the reading of the original P on the contact glass 3 prior to the start of conveyance of the first original P. As the white reference plate, a dedicated white reference plate may be provided at a predetermined reference position, or the reflection guide plate 27 may be used as the white reference plate.
[0022]
  Then, the color image reading apparatus 1 is shown in FIG. 2 which is an overall block diagram of the color image reading apparatus 1 and FIG. 3 which is a data flow diagram of image data of the color image reading apparatus 1. SCU41, VIOB42, ADU43, OIPU44, NIC45, ISIC46, PSU (power supply unit) 47, power switch 48, plug 49, scanner motor 50, etc. which control operation of the color image reading apparatus 1 including the main body and the ARDF 20 are provided. .
[0023]
  The color image reading device 1 converts the reflected light of the original P incident on the color CCD 9a on the CCD drive unit 9 into RGB analog signals having voltage values corresponding to the light intensity in the color CCD 9a. Each color analog signal is divided into odd bits and even bits and output to the VIOB 42. The analog image signal of the CCD drive unit 9 is subjected to the analog processing circuit 42a on the VIOB 42, the dark potential portion is removed, the odd bits and the even bits are combined, and the gain is adjusted to a predetermined amplitude. 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 after image processing such as gamma correction and MTF correction is performed by the RIPU 41a on the SCU 41 from the VIOB 42, together with the synchronization signal and the image clock. Output as a video signal. Here, the shading correction is performed based on correction data calculated from the shading data held in the memory of the shading ASIC 42c.
[0024]
  The video signal output from the RIPU 41a is output to the OIPU 44, and the OIPU 44 performs predetermined image processing on the input video signal and outputs it again to the SCU 41.
[0025]
  The video signal input to the SCU 41 is input to the VIDEO input switching circuit 41b, and the video signal is input from the RIPU 41a to the other input of the VIDEO input switching circuit 41b to select whether or not to perform image processing in the OIPU 44. It can be configured.
[0026]
  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 SDRAM. The image data stored in the image memory is sent to the SCSI controller 41d and transferred to an external device such as a personal computer or a printer via the SCSI-I / F.
[0027]
  On the SCU 41, a CPU 60 (see FIG. 4), a ROM (not shown), and a RAM (not shown) are mounted. The CPU 60 controls the SCSI controller 41d and uses a SCSI-I / F to connect a personal computer or the like. Communicate with external devices. In addition, the CPU 60 uses a video signal output from the VIDEO input switching circuit 41b as a personal computer, a printer, or the like via the IEEE 1394-I / F via the IEEE 1394 controller, the IEEE 1394-I / F, and the network 45 via the network 45 I / F. Communication with external devices. Furthermore, the CPU 60 also performs timing control of the traveling body motor 10 which is a stepping motor of the scanner body, the paper feed motor of the ARDF 20, and the transport motor.
[0028]
  The ADU 43 has a function of relaying power supply of electrical components used for the ARDF 20. The input port connected to the CPU 60 on the SCU 41 is connected to the operation panel (SOP) 50 of the color image reading apparatus 1 main body via the VIOB 42. Although not shown, a start switch and an abort switch are mounted on the operation panel (SOP) 50. When each switch is pressed, the CPU 60 of the SCU 41 detects that the switch is turned on via the input port.
[0029]
  FIG. 4 is a block diagram relating to the image reading process of the color image reading apparatus 1. From the RIPU 41a which is an image processing LSI to the SBU 9 which is a CCD drive unit, LSYNC (main scanning line synchronization signal) and LGATE (main scanning line). By outputting (data output period), image data is output from the SBU 9. The flow of the image data is SBU9 → RIPU 41a → memory control LSI (SIBC2) 41c → SCSI controller 41d → external (personal computer or the like). Further, ON / OFF of image output from the CPU 60 is provided as a known technique in the image processing LSI (RIPU) 41a, and is controlled by rewriting the internal register.
[0030]
  Interrupt signal from the memory control LSI 41c (this interrupt is generated when the memory state is full, near full, or empty, and the state is indicated by a register provided as a known technique in the memory control LSI (SIBC2) 41c not shown). Can be distinguished) is input to the CPU 60. The CPU 60 also performs motor control of the traveling body motor 10 for moving the traveling body.
[0031]
  Next, the operation of the present embodiment will be described. In the color image reading apparatus 1, the original P is sent onto the DF original glass 38, and the conveyance locus is U-shaped as shown in FIGS. 5 and 6. Depending on the angle at which the document P enters the reading section or the discharge angle, the distance between the DF document glass 38 and the document P varies greatly as shown in FIG. In order to be in a stable region as an image, the original P to be read needs to be at a certain distance from the DF original glass 38. Normally, however, the portion in contact with the DF original glass 38, that is, FIG. The original stable area is optimal, and it is necessary to read the original P within the range of the original stable area. On the other hand, if the original P is not in close contact with the DF original glass 38, the behavior of the original P is not constant, and the variation in the read data increases, which 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, the stable region does not necessarily come to the initial reading position.
[0032]
  Therefore, in the color image reading apparatus 1 of the present embodiment, for example, the adjusted original P having a constant density is set and conveyed on the original table 21, while the traveling body is ± sub-scanned around the initial reading apparatus P0. The document P is read at each point + Pn, + Pn-1,..., + P1, P0, -P1,. Try to find (best point).
[0033]
  FIG. 7 shows a flowchart of reading position adjustment processing by the color image reading apparatus of the present embodiment. A document P having a constant density is set on the document table 21 (step S101). First, the traveling body is moved to the position of the white reference plate, and shading data is collected (step S102). While returning to the position, the point number n is initialized (step S103). Next, the conveyance of the original P is started (step S104), and the traveling body is moved to the adjusted read data measurement position + Pn (step S105). Then, the color image reading apparatus 1 reads a predetermined line of the original P at + Pn, and obtains read data at this point (step S106). Subsequently, the point number n is decremented by “1” (n = n−1) (step S107), and it is checked whether it is within a predetermined reading area (step S108). When the decremented position is not within the reading area, the color image reading apparatus 1 proceeds to ΔPmin calculation processing (step S109). On the other hand, if it is within the reading area, it is checked whether there are any remaining points (step S110). That is, it is checked whether the point number has reached -n. If there is a remaining point in step S110, the color image reading apparatus 1 returns to step S105, reads a predetermined line of the document P as described above, and obtains read data at that point. When there is no remaining point in step S110, the color image reading apparatus 1 performs ΔPmin calculation processing (step S111), and determines a reading adjustment position (appropriate reading position) P0 '(step S112). The same applies when the ΔPmin calculation process is performed in step S109.
[0034]
  Here, as shown in FIG. 6, the center of the initial reading position is “P0: initial value”, and a position having a reading range in the + direction (sub scanning direction +, direction of the contact glass 3) from the position of P0. + Pn, the position slightly shifted in the 0 direction exceeds + Pn-1, + Pn-2 ... + P1, P0, and the-direction (sub-scanning direction-opposite to the direction of the contact glass 3) is -P1, -P2,- Let Pn-1 and -Pn. It should be noted that -Pn is in the reading area, like +.
[0035]
  Each position of -Pn to + Pn is the number of input drive pulses when performing open loop control such as a step motor from the reference position (or adjacent point), and if it is a feedback system such as a brush motor with an encoder, an encoder It can be managed by the number of pulses.Whether it is within the reading region (step S108 in FIG. 7) can be determined by comparing the number of input drive pulses and the number of encode pulses with a predetermined value.
[0036]
  The color image reading device 1 stops the first traveling body on which the lamp 4 and the first mirror 5 are mounted at + Pn, and scans the moving document P for several lines to several dozen lines. In this case, the number of main scanning data is arbitrary. Next, the first traveling body is moved to the position of + Pn-1, and the same data is similarly read. The process is sequentially repeated until the position of -Pn is exceeded beyond P0. After the implementation, the first traveling body is returned to the initial reference point and waits.
[0037]
  The color image reading apparatus 1 performs shading correction on the data of the original P read at each position between + Pn and -Pn according to the flow of the data image described above, and stores it as it is in a memory (not shown) inside the shading ASIC 42c. . Note that the memory capacity can appropriately change the main scanning direction, the number of sub-scanning line data, the number of stop points, and the stop interval, and the measurement accuracy increases as the number of data increases.
[0038]
  The ΔPmin calculation and the reading adjustment position (appropriate reading position) are determined as follows. The CPU 60 calculates and compares the data read at each point (stop point) by a predetermined amount of data displacement (for example, min-max difference) at each stop point. In this case, the point with the smallest amount of data displacement is where the original P is stable in the sub-scanning direction. Therefore, the point is set as a reading position in subsequent ADF sheet through reading.
[0039]
  For example, when the maximum-min difference of data output (full range 12 bits = 4096 digit) when passing through the white original P is ΔPn and the minimum ΔPmin is found from the calculation result (unit digit)
ΔPn = 300 (max: 3960, min: 3660)
ΔPn−1 = 280 (max: 3960, min: 3680). . .
ΔP2 = 100 (max: 3960, min: 3860)
ΔP1 = 50 (max: 3960, min: 3910)
ΔP0 = 80 (max: 3960, min: 3880)
ΔP−1 = 130 (max: 3960, min: 3830). . .
ΔP−n = 400 (max: 3960, min: 3560)
If so, the minimum ΔPmin = ΔP1 is selected.
[0040]
  Therefore, P1 becomes the best point, and the CPU 60 calculates the necessary distance from P0, which is set as the reading position P0 ′ when the next ADF is used, and the position data of P1 is stored in P0 ′ by SRAM (not shown). Rewrite.
[0041]
  In this case, the length of the adjustment original P is not limited as long as the measurement can be performed during this period. Even if the adjustment original P is short, it can be dealt with by reducing the original feed speed. Further, as the adjustment document P, a document that has a uniform density and can withstand conveyance by the ARDF 20, for example, a document that is difficult to be scratched or peeled off is used. As an example of the original P having a uniform density, for example, there is a document printed uniformly, such as a Kodak gray scale chart. Since the difference in the reflected light from the uniform original P density is taken, there is no problem if the light and darkness of the chart to be used is within the input range. Is easy to do. Also, if the reflectance of the original P is larger than necessary, the output of the CCD may reach a saturation voltage and may be out of the input range, so that it is difficult to determine the difference.
[0042]
  In the present invention, a normal character original (such as an office document) is used as the adjustment original P, and the margin of the original is read. That is, as shown in FIG. 8, most ordinary character originals have margins of several millimeters near the four sides of the rectangle (up, down, left and right of the paper). If the scanner can detect the paper passing size and the feeding direction or can input information as information, the adjustment measurement can be realized with a substitute document if there is a certain amount of continuous density uniform margin in the sub-scanning direction.
[0043]
  Therefore, the adjustment can be performed not only at the time of factory shipment adjustment by a special manuscript but also at the user level. For example, when an original of different paper types is passed for each scan job, if only the first sheet is passed in the adjustment mode, a good image can be obtained each time.
[0044]
  If the ARDF 20 can mount a plurality of documents P, the CPU 60 prepares a document P to be read as a normal image next to the adjusted document, so that the CPU 60 detects the second document P in the SRAM when it detects the second document P. With reference to the position of P0 ′, the motor is driven to move the carriage to P0 ′, and continuous reading is possible.
[0045]
  In the margin reading, main scanning data capture is measured in the same manner for 4 to 5 mm from the edge of the document P (if it is 600 dpi, 95 to 120 dots), the data during that time is collected, and the above calculation is performed. Find the proper position. Since the ARDF 20 is used, dust in the ARDF 20 (paper dust, toner of the output document such as PPC) 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 and the result is affected. Moreover, since there is paper flapping depending on the measurement location, it is desirable that the number of data samples is large. In order to increase the measurement accuracy, it is effective to increase the number of samples at the time of adjustment and increase the number of samples. Also, depending on the type of paper, paper dust is difficult to be generated. Therefore, if the paper is not PPC-printed, it is possible to clean the transport path dust by increasing the number of paper passes. The reliability of the detected data can be improved as the value of the number increases.
[0046]
  When a plurality of adjusted originals (normal 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 denoted by the same step numbers, and the description thereof is omitted. However, in step S103, the traveling body is returned to the initial reading position, and the number of originals m is also initialized in addition to the point number n. In step S106, the margin portion of the document P is read by a predetermined line to obtain read data at the point.
[0047]
  In FIG. 9, when there is no remaining point in step S110 for one adjusted document in FIG. 9, the color image reading apparatus 1 decrements the count value m of the counter that counts the number of remaining document sheets by “1” (step 1). S201), it is checked whether there is a remaining number of originals m (whether m = 0) (step S202).
[0048]
  If the remaining number of sheets m is not “0” in step S202, the color image reading apparatus 1 returns to step S105 and performs the same processing as described above. If the remaining number of sheets m becomes “0” in step S202, ΔPmin An arithmetic process is performed (step S111), and the reading adjustment position P0 ′ is determined (step S112).
[0049]
  As described above, according to the color image reading apparatus 1 of the present embodiment, the optical system of the lamp 4 and the first mirror 5 to the fourth mirror 8 is mounted on the traveling body, and the ARDF (automatic duplex document feeder) 20. When the original P conveyed to the reading position is irradiated with light from the lamp 4 and the reflected light from the original P is introduced into the CCD drive unit (SBU) 9 by the optical system to read the image of the original P. The original P having a uniform density as a whole 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, and the reflected light from the adjustment original is reflected on the optical system on the traveling body. Thus, the appropriate position of the traveling body is calculated based on the density data output from the CCD drive unit 9 and set as the reference reading position.
[0050]
  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 it is possible to read a stable image with high quality.
[0051]
  Further, the color image reading apparatus 1 according to 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, and calculates a reference reading position. It is set as.
[0052]
  Therefore, it is possible to appropriately correct variations among devices generated from individual parts of the color image reading apparatus 1 without preparing a special document that is expensive as an adjustment document and difficult to obtain. A stable image can be read with high quality and at low cost.
[0053]
  Further, a plurality of adjusted originals (normal originals) P are conveyed from the ARDF 20 to the reading position, and an appropriate position of the traveling body is calculated based on density data obtained when the plurality of adjusted originals are read. If it is set as, it is possible to cancel image noise that is likely to occur at the time of reading by repeatedly performing a reading operation, and it is possible to set a more accurate reference reading position and obtain a more stable image.
[0054]
  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0055]
【The invention's effect】
  According to the image reading apparatus of the present invention, it is possible to appropriately correct variations between apparatuses generated from individual components of the image reading apparatus, and it is possible to read a stable image with high quality. Further, a normal document having a margin is conveyed as an adjustment document, the margin portion of the document is read, an appropriate position of the traveling body is calculated, and set as a reading position of the traveling body when the document is read while moving. Therefore, it is possible to appropriately correct variations between individual devices of the image reading device without preparing a special manuscript that is expensive and difficult to obtain as an adjustment manuscript, and is stable. Images can be read with high quality and at low cost. In addition, by transporting multiple documents from the automatic document transport mechanism and repeatedly scanning and calculating the documents, it is possible to cancel image noise that is likely to occur at the time of reading, and to set a more accurate reference reading position. 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 an image reading apparatus of the present invention is applied.
FIG. 2 is an overall block configuration diagram of the color image reading apparatus in FIG. 1;
3 is a data flow diagram of the color image reading apparatus of FIG.
4 is a block configuration diagram of a reading processing unit of the color image reading apparatus of FIG. 1;
5 is a front view showing a document state 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 the document reading position at the DF document glass position of FIG. 5;
7 is a flowchart showing reading position adjustment processing by the color image reading apparatus of FIG. 1;
FIG. 8 is a conceptual diagram when a normal character document is used as an adjustment document.
FIG. 9 is a flowchart showing a reading position adjustment process when a plurality of adjustment documents are used by the color image reading apparatus of FIG.
[Explanation of symbols]
1 Color image reader
2 Main unit housing
3 Contact glass
4 lamps
5 First mirror
6 Second mirror
7 Third mirror
8 Lens
9 CCD drive unit (SBU)
10 Running body motor
11 System control unit
20 ARDF
21 Document table
22 Calling roller
23 Paper feed belt
24 Transport rollers
25 Separation roller
26 First conveying roller
27 Reflection guide plate
28 Second transport roller
29 Paper discharge roller
30 Reverse roller
31 branch claws
32 Inversion table
38 Document glass for DF
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 ISIC
47 PSU (power supply unit)
48 Power switch
49 plug
50 Scanner motor
60 CPU

Claims (2)

A light source and an optical system are mounted on the traveling body, light from the light source is irradiated to a document conveyed to a reading position by an automatic document conveyance mechanism, and reflected light from the document is introduced into a photoelectric element by the optical system. In the image reading apparatus for reading the image of the original,
Wherein the traveling body is moved successively a predetermined distance in the sub-scanning direction is stopped, for each stop position, irradiating light from said light source on said traveling body to the document being moved to be conveyed from the automatic document conveying mechanism to, and introduced into the photoelectric element reflected light by the optical system on the traveling body from the document, reads predetermined line margins of the document, the displacement of the read data of the predetermined lines in each stop position An amount is calculated, a position corresponding to a minimum displacement amount among the displacement amounts of the read data at each stop position is determined as an appropriate position of the traveling body, and the appropriate position is sub-scanned by the traveling body of the moving document. An image reading apparatus that is set as a reading position in a direction. The image reading apparatus according to claim 1, wherein a plurality of the documents are conveyed from the automatic document conveyance mechanism, and a displacement amount of the read data at each stop position is calculated from the read data of the plurality of documents. An image reading apparatus.

Images