JP2010016514A - Original reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original reading device for shortening a time until reading is made possible when a power is supplied or when a mode is restored from an energy saving mode. <P>SOLUTION: This original reading device with at least a book reading function includes: a pressure plate means for press-fitting a read original to contact glass; a first white reference image member installed in the pressure plate means for forming a reference white image for shading correction; and a control means for reading the image of the first white reference image member in a stop status before a carriage moving in a reading optical system is restored to a reference position when a power is supplied or when a mode is restored from an energy saving mode, and for creating reference data for shading correction, and for performing white level adjustment. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an original reading apparatus having at least a book reading function.

  Generally, it has a scanning optical system that forms an image of a document on a document table on a CCD image sensor, a signal processing circuit having a gain after the CCD image sensor, and an A / D converter that converts an analog signal into a digital signal. In a document reading apparatus that performs gain correction and shading correction by reading density data of a reference white plate at the time of reading a document image, the reflected light of a reference white plate (reference white image for shading correction) that serves as a reference for shading correction is read. Shading data is generated and an image with the proper density is obtained by correcting the scanned original data. Shading data is generated when the power is turned on or when the scanner engine is turned off (hereinafter referred to as “energy saving”). `` Return from mode ''), and a copy using an automatic document feeder (ADF). It is performed when reading the image of document sheets continuously.

  On the other hand, the carriage that moves the scanning optical system below the contact glass in the sub-scanning direction is not guaranteed to stop at a predetermined home position when the power is turned on. Therefore, a predetermined homing process is performed for confirming the carriage position, and then the carriage is moved under the reference white plate to read the image of the reference white plate.

Further, even when the carriage is moved below the reference white plate when shifting to the energy saving mode, there is no guarantee that the carriage is positioned below the reference white plate when returning from the energy saving mode. Therefore, even when returning from the energy saving mode, it is necessary to perform a determination process for determining whether the carriage is positioned below the reference white plate and a homing process.
JP 2004-159356 A Japanese Patent Laid-Open No. 10-224624

  However, performing these processes not only increases the load on the control system, but also has a problem that it takes time until the original can be read when the power is turned on or when returning from the energy saving mode.

  SUMMARY An advantage of some aspects of the invention is that it provides a manuscript reading apparatus capable of shortening the time required for reading at power-on or when returning from an energy saving mode.

  The present invention is an original reading apparatus having at least a book reading function, a pressure plate means for pressing a read original against a contact glass, and a first white image provided on the pressure plate means for forming a reference white image for shading correction. For the shading correction by reading the image of the first white reference image member in the stop state before returning the carriage that moves the reading optical system to the reference position when the power is turned on or the energy saving mode is restored. Control means for creating reference data and adjusting white level is provided.

  The pressure plate opening / closing detection sensor means for detecting opening / closing of the pressure plate, and a second white reference image member provided in the vicinity of the contact glass and forming a reference white image for shading correction, the control means, When generating the shading correction reference data, if the pressure plate opening / closing detection sensor detects the opening of the pressure plate, the carriage is moved to the reading position of the second white reference image member, and the second white reference image member is read. The image of the reference image member is read to create the shading correction reference data.

  Further, the apparatus further includes an automatic document reading device that conveys the read document placed on the document table one by one to the reading position and is provided with a pressure plate combined member that also serves as the pressure plate means, and the reading document conveying means has a shading correction function. A third white reference image member for forming a reference white image is provided, and a fourth white reference image member for forming a reference white image for shading correction is provided on the pressure plate combined member.

  Further, when the gain value after the white level adjustment is not an appropriate value, the control means moves the carriage to the reading position of the second white reference image member, and the second white reference image member , The shading correction reference data is created, and the white level adjustment is performed again.

  Therefore, according to the present invention, the time required for creating the shading correction reference data when the power is turned on or when returning to the energy saving mode can be greatly reduced. The effect that the time until it becomes possible can be greatly shortened is obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an example of a schematic configuration of a document reading apparatus according to an embodiment of the present invention. The image reading apparatus 1 includes an automatic document conveyance unit (ADF) 1a that separates read documents one by one from the document table 2 and conveys them to a reading position RL, and an image reading unit 1b that reads a document image at the reading position line by line. Consists of. Further, the image reading unit 1b includes two document reading functions, a sheet scan type document reading function (sheet scan mode) and a book scan type document reading function (book scan mode).

  In the automatic document feeder unit 1 a, the read document PP placed on the document table 2 is taken out by the pickup roller 3 at the uppermost position and sent to the separation unit 4. They are separated one by one and delivered to the delivery roller 5. The delivery roller 5 sends out one read original in the transport direction through the guide member GG.

  As a result, the read original PP is sandwiched between the transport roller 6 and the transport drum 7, transported in close contact with the surface of the transport drum 7, passes through the reading position RL, and is transported to the discharge roller 8. The paper is discharged onto the paper discharge tray 9 by the discharge roller 8.

  In the document reading unit 1b, a sheet scanning contact glass 10 is disposed corresponding to the reading position RL. The dimension of the contact glass 10 in the sub-scanning direction is about 4 (mm).

  Further, a contact glass 11 for book scanning is disposed on the right side of the contact glass 10. The reference white plate WLa is used to construct a white reference image for shading correction.

  The lamp 12 illuminates the original surface of the read original PP, and the reflected light from the read original PP is sequentially reflected by the first mirror 13, the second mirror 15, and the third mirror 16 to form a lens. 18, is focused by the lens 18, and is irradiated onto the CCD line image sensor 20 provided on the substrate 19.

  The lamp 12 and the first mirror 13 are mounted on the first carriage 14 and reciprocated in the sub-scanning direction SS, and the second mirror 15 and the third mirror 16 are mounted on the second carriage 17 and mounted on the sub-scanning direction SS. Reciprocates in the scanning direction SS. Further, in order to maintain the optical path length from the contact glass 10 to the CCD line image sensor 20, the second carriage 17 is moved at a speed half that of the first carriage 16.

  The scanner motor 21 is for driving the first carriage 14 and the second carriage 17.

  The automatic document transport unit 1a is configured to open and close with respect to the contact glass 11 as a whole, and a portion facing the contact glass 11 constitutes a pressure plate member for pressing a book document or the like against the contact glass 11. is doing. In this pressure plate member, a reference white plate WLb constituting a white reference image for shading correction is disposed in the scan range of the lamp 12 by the carriage.

  Further, a reference white plate member (not shown) constituting a white reference image for shading correction is disposed on the surface of the transport drum 7 facing the contact glass 10.

  As described above, since the reference white plate member is provided on the surface of the transport drum 7 and the surface of the pressure plate member of the automatic document transport unit 1a, the position of the carriage 14 is undefined when the power is turned on or when the energy saving mode is restored. Even if it exists, the probability that the irradiation position (namely, image reading position) of the light source 12 will be in the state which reads the image of any reference | standard white board member will be very high.

  In the book scan mode, the CCD line image sensor 20 is driven while moving the carriage in the sub-scanning direction SS to read the original image on the contact glass 11.

  In the sheet scan mode, it is possible to read a plurality of documents continuously. In this case, the carriage does not move and the lamp 12 is stopped at the reading position RL.

  FIG. 2 shows another example of a schematic configuration of a document reading apparatus according to an embodiment of the present invention. In this figure, the same parts as those in FIG.

  In this embodiment, the automatic document transport unit 1a is excluded from the configuration of FIG. 1, and the image reading unit 1b has only a book scan type document reading function. A pressure plate member BP that presses the read document against the contact glass 11 is provided. The pressure plate member BP includes a reference white plate WLb that forms a white reference image for shading correction in the scanning range of the reading light source by the carriage 14. 'Is arranged.

  Thus, in this embodiment, since the reference white plate WLb ′ is provided on the surface of the pressure plate member BP, even if the position of the carriage 14 is indefinite when the power is turned on or the energy saving mode is restored, the light source 12 The light irradiation position (i.e., the image reading position) has a very high probability of reading the image of the reference white plate WLb ′.

  FIG. 3 shows an example of a control system of the document reading apparatus according to one embodiment of the present invention.

  In the figure, a CPU (Central Processing Unit) 31 controls the operation of each part of the document reading device and realizes a function of performing communication with other devices. (Only memory) 32 stores program data executed by the CPU 31 and various data necessary for the system, and a RAM (random access memory) 33 constitutes a work area of the CPU 31 and the like. is there.

  The operation display unit 34 is a hardware resource that includes an operation key for the user to operate the document reading device, a display device for displaying a status of the device to the user, and the like, and constitutes a user interface. The external interface circuit 35 is connected to an external device (for example, a host device, etc.) and exchanges various data with the external device.

  The input / output control unit 36 is disposed in the vicinity of the contact glass 11, and the document size detection sensor 37 for detecting the size of the document placed on the contact glass 11, the automatic document transport unit 1 a, or the pressure plate BP includes the contact glass. 11, an ADF (pressure plate) opening / closing sensor 38 for detecting whether the automatic document feeder unit 1 a or the pressure plate BP is separated from the contact glass 11 (open), a scanner motor A motor driving unit 39 for driving 21 and the like, a lamp driving unit 40 for driving and driving the lamp 12, a document reading unit 41 for driving the CCD line image sensor 20 to form read image data, and a carriage Home position to detect whether or not it is located at a predetermined home position It is used for exchanging various data between the capacitors 42.

  These CPU 31, ROM 32, RAM 33, operation display unit 34, external interface circuit 35, and input / output control unit 36 are connected to the internal bus 43, and data exchange between these elements is mainly performed in this manner. This is done via the internal bus 43.

  The power supply unit 45 has a function of supplying power to each element of the document reading apparatus and switching the power supply destination in the energy saving mode and the normal operation mode, and shifting from the normal operation mode to the energy saving mode. The CPU 31 controls the return from the energy saving mode to the normal operation mode.

  FIG. 4 shows a schematic configuration of the document reading unit 41.

  In the figure, a timing generator 51 outputs various timing signals for driving the CCD line image sensor 20, and an analog image signal output from the CCD line image sensor 20 is an analog signal processor 52. Has been added. Various timing signals are output from the timing generation unit 51 to the analog signal processing unit 52 and the A / D (analog / digital) converter 53.

  The analog signal processing unit 52 inputs an analog image signal output for each line from the CCD line image sensor 20, and offset clamp, sample / hold (S / H), black offset correction, In addition, analog signal processing such as signal amplification is applied, and the output signal is applied to the A / D converter 53.

  The A / D converter 53 converts the output signal of the analog signal processing unit 52 into a corresponding digital image signal (digital data) and performs a predetermined shading correction process.

  Here, the black offset correction is a function for detecting a black level in an arbitrary period and performing feedback correction so that the level becomes a specified black target value. This black level detection is performed in an empty transfer area (described later). (Since the empty transfer pixel is not a physical pixel, a wide period can be secured for the OPB area).

  The timing generator 51 also performs register control of the analog signal processor 52 (not shown).

  FIG. 5 shows an example of processing at power-on or when returning from the energy saving mode.

  First, it is determined whether the state is power-on or return from the energy saving mode (decision 101). When it is determined that the power is turned on in the determination 101 (the result of the determination 101 is YES), a predetermined power-on process (processing 102) is performed, and when returning from the energy saving mode (the result of the determination 101 is NO), A predetermined energy saving return process (process 103) is performed.

  Next, the lamp is immediately turned on to adjust the white level (process 104). After waiting for a certain time until the lamp light quantity is stabilized, a predetermined white level adjustment (processing 105) is performed. Next, a predetermined black level confirmation process (process 106) is performed, and the carriage is moved to the home position (HP) (process 107).

  Next, a predetermined determination process is performed to determine whether there is a gain error in white level adjustment (determination 108). When there is no error (the result of determination 108 is YES), the lamp 12 is turned off (process 109). Thereafter, it is determined whether there is no error in black level confirmation (decision 110). If there is no error (the result of determination 110 is YES), the scanner is set in a standby state (process 111). If there is an error (the result of determination 110 is NO), predetermined error processing such as error display is performed (processing 112).

  Further, when it is determined that the white level gain error is determined in the determination 108 (the result of the determination 108 is NO), an error display or error processing is performed immediately by setting the number of times of the error (determination 113) ( Processing 112) and the adjustment position are set below the reference white plate WLa (processing 114), and the white level can be adjusted again (return to processing 105). At this time, the white level can be adjusted immediately by maintaining the lamp on.

  In this way, in this embodiment, the homing operation after the power-on process, which has been conventionally performed, can be omitted, so that the lamp can be turned on immediately and the process of moving the carriage below the reference white plate WLa can be omitted. In return from the energy saving mode, after moving the carriage to the home position, it can be determined whether or not the carriage is under the reference white plate WLa, and it is determined that the white level adjustment has been performed outside the reference white plate WLa. In this case, the process of moving the carriage again from the home to below the reference white plate WLa and performing the process after white level adjustment can be omitted.

  Therefore, in this embodiment, since the processing steps can be largely omitted as compared with the prior art, it is possible to greatly reduce the time until reading is possible when the power is turned on or when the energy saving mode is restored.

  FIG. 6 shows an example of white level adjustment processing.

  White level adjustment performed when the power is turned on or when returning from the energy saving mode. When the carriage at that time is not the reference white plate WLa position but the reference white plate WLb, WLb ′, the white level that can be tolerated under the influence of dust, dirt, etc. The adjustment value may not be obtained.

  Therefore, when performing white level adjustment, it is acceptable not to perform white level adjustment by only one main scan, but to move the carriage to avoid dust and dirt, read a plurality of lines, and take the average. A white level adjustment value can be obtained.

  That is, after setting a wait until the light quantity is stabilized after the lamp is lit, the flow proceeds to the white level adjustment flow. White level gain calculation is performed based on the data obtained after acquiring the data at the current carriage position (processing 201 and 202). Next, the carriage is moved to acquire a plurality of data (process 203). It is determined whether the gain calculation is performed on another line by moving the carriage. If the carriage has not moved by a predetermined amount (the result of determination 204 is NO), the flow of processes 201 to 203 is repeated. If the carriage has moved by a predetermined amount and white level adjustment has been performed for a plurality of lines (the result of determination 204 is YES), the process proceeds to black level confirmation processing (processing 205).

  By the way, when the automatic document feeder unit 1a or the pressure plate BP is open or in a half-open state, there is a possibility that the white level cannot be adjusted normally when the carriage is positioned other than the reference white plate. In addition, since the automatic document feeder unit 1a or the pressure plate BP is open, there is a concern that the user directly receives strong light from the lamp 12.

  In order to avoid such a situation, for example, the ADF (pressure plate) open / close sensor 38 is used to grasp the open / close state. When the automatic document feeder unit 1a or the pressure plate BP is open, the adjustment is performed under the reference white plate WLa as usual. However, as long as there is no movement of the carriage due to some external factor, the carriage is waiting under the reference white plate WLa when returning from the energy-saving mode. Therefore, even if the automatic document transport unit 1a or the pressure plate BP is open, the white level is on the spot. Make adjustments.

  An example of processing in this case is shown in FIGS.

  When the result of determination 301 is YES when the power is turned on, a predetermined power-on process (process 302) is executed, the signal of the ADF (pressure plate) opening / closing sensor 38 is examined, and the automatic document conveyance unit 1a or the pressure plate BP is checked. Is determined to be closed (determination 303).

  When the result of determination 303 is YES, the lamp is immediately turned on to adjust the white level (processing 304). After waiting for a certain time until the lamp light quantity becomes stable, a predetermined white level adjustment (processing 305) is performed. Next, a predetermined black level confirmation process (process 306) is performed, and the carriage is moved to the home position (HP) (process 307).

  Next, a predetermined determination process is performed to determine whether there is a gain error in white level adjustment (determination 308). When there is no error (the result of determination 308 is YES), the lamp 12 is turned off (process 309). Thereafter, it is determined whether there is no error in the black level confirmation (determination 310). If there is no error (the result of determination 310 is YES), the scanner standby state is set (process 311). If there is an error (the result of determination 310 is NO), predetermined error processing such as error display is performed (processing 312).

  Further, when it is determined that the gain error is a white level in the determination 308 (the result of the determination 308 is NO), an error display or error processing is immediately performed by setting the number of times of the error (determination 313) ( Processing 312), the adjustment position is set below the reference white plate WLa (processing 314), and the white level can be adjusted again (return to processing 305). At this time, the white level can be adjusted immediately by maintaining the lamp on.

  On the other hand, when the automatic document feeder unit 1a or the pressure plate BP is open and the result of determination 303 is NO, the carriage is moved to the home position (HP) (homing process; process 315), and the lamp is lit (process 316). The carriage is moved below the reference white plate WLa (process 317), and white level adjustment (process 318) is performed. Next, the process proceeds to process 306, and subsequent processes are executed.

  In addition, when the result of the determination 301 is NO when returning to the energy saving mode, processing for returning to a predetermined energy saving mode is performed (processing 320). Next, it is checked whether or not the automatic document feeder unit 1a or the pressure plate BP is closed (determination 321). When the result of determination 321 is YES, the process proceeds to process 304, and the subsequent processes are executed.

  If the automatic document feeder unit 1a or the pressure plate BP is open and the result of determination 321 is NO, it is checked whether the home position sensor 42 is on (determination 322). When the result of determination 322 is YES, this is a case where the carriage is positioned at the home position, and the process proceeds to process 315 and subsequent processes are executed.

  If the result of determination 322 is NO, the carriage may be waiting under the reference white plate WLa, so the lamp is immediately turned on (process 323), white level adjustment (process 324), and black level confirmation. (Process 325) A series of steps of moving the carriage to the home (Process 326) is performed in order.

  Thereafter, it is determined whether the carriage has returned from the energy saving mode under the reference white plate WLa (determination 327). This determination can be made by comparing the number of drive pulses of the scanner motor 21 in advance by storing the number of drive pulses of the scanner motor 21 at a distance from the reference white plate WLa to the home position, for example, by counting the number of drive pulses of the scanner motor 21.

  When the result of determination 327 is NO, the process proceeds to process 317 and subsequent processes are executed. When the result of determination 327 is YES, the process proceeds to determination 308 and subsequent processing is executed.

  By the way, when the original used by the user last time remains on the contact glass, there is a possibility that the white level cannot be adjusted normally. That is, there is a concern that the white level adjustment may be performed with reference to the read document when the white level adjustment is performed by the automatic original conveyance unit 1a or the reference white plates WLb and WLb 'of the pressure plate BP.

  Therefore, it is determined whether or not the read document PP remains on the contact glass 11 using the document size detection sensor 37, and according to the determination result, the white level is adjusted using the reference white plate WLa, or the reference is detected. It may be determined whether white level adjustment is performed using the white plates WLb and WLb ′.

  An example of processing in this case is shown in FIGS.

  When the result of determination 401 is YES when the power is turned on, a predetermined power-on process (process 402) is executed, the signal of the document size detection sensor 37 is examined, and the read document PP is positioned on the contact glass 11. It is determined whether or not it is not performed (determination 403).

  If the read original PP is not positioned on the contact glass 11 and the result of determination 403 is YES, the lamp is immediately turned on to adjust the white level (process 404). After waiting for a certain time until the lamp light quantity becomes stable, a predetermined white level adjustment (process 405) is performed. Next, a predetermined black level confirmation process (process 406) is performed, and the carriage is moved to the home position (HP) (process 407).

  Next, a predetermined determination process is performed to determine whether there is a gain error in white level adjustment (determination 408). When there is no error (the result of determination 408 is YES), the lamp 12 is turned off (process 409). Thereafter, it is determined whether or not there is an error in black level confirmation (determination 410). If there is no error (the result of determination 410 is YES), the scanner standby state is set (process 411). If there is an error (the result of determination 410 is NO), predetermined error processing such as error display is performed (processing 412).

  Further, when it is determined that the white level gain error is determined in the determination 408 (the result of the determination 408 is NO), an error display or error processing is immediately performed by setting the number of times of the error (determination 413) ( Then, the white level can be adjusted again (process 405) by setting the adjustment position below the reference white plate WLa (process 414). At this time, the white level can be adjusted immediately by maintaining the lamp on.

  On the other hand, when the read original PP is located on the contact glass 11 and the result of determination 403 is NO, the carriage is moved to the home position (HP) (homing process; process 415), and the lamp is lit (process). 416), then, the process proceeds to process 414, the carriage is moved below the reference white plate WLa, and the subsequent processes are executed.

  Further, when the result of the determination 401 is NO when returning to the energy saving mode, processing for returning to a predetermined energy saving mode is performed (processing 420). Next, it is checked whether or not the home position sensor 42 is on (decision 422). When the result of determination 422 is YES, this is a case where the carriage is positioned at the home position, and the process proceeds to process 415 and the subsequent processes are executed.

  If the result of determination 422 is NO, the carriage may be waiting under the reference white plate WLa, so the lamp is immediately turned on (process 423), white level adjustment (process 424), and black level confirmation. (Processing 425) A series of steps of moving the carriage to the home (Processing 426) is sequentially performed.

  Thereafter, it is determined whether or not the carriage has returned from the energy saving mode under the reference white plate WLa (determination 427). This determination can be made by comparing the number of drive pulses of the scanner motor 21 in advance by storing the number of drive pulses of the scanner motor 21 at a distance from the reference white plate WLa to the home position, for example, by counting the number of drive pulses of the scanner motor 21.

  When the result of determination 427 is NO, the process proceeds to process 414 and subsequent processes are executed. If the result of determination 427 is YES, the process proceeds to determination 408 and subsequent processing is executed.

  By the way, when the power is turned on or when the energy saving mode is restored, white level adjustment is performed at the boundary between the reference white plate WLa and the automatic document feeder unit 1a or the reference white plates WLb and WLb ′ of the pressure plate BP, or between the reference white plate WLa and the contact glass 10. It is necessary to consider the case where the white level error does not occur due to some influence. In this case, when the adjustment is performed in the effective region, the determination can be made with high accuracy by comparing with the normal gain of the previous adjustment.

  For example, when adjusting the white level, the reference white plate WLa, the read original region range of the reference white plates WLb and WLb ′, and the white portion of the transport drum 7 are set as effective adjustment regions. The distance from the home position to the boundary (prohibited area) of each area is stored in advance as the number of drive pulses of the scanner motor 21 so that the number of drive pulses is counted when the carriage is returned to the home position after white level adjustment. By performing the comparison, it can be determined whether the adjustment is made in the adjustment effective area. Further, even when adjustment is performed in the effective region, it is possible to make a precise determination by comparing with the normal gain of the previous adjustment.

  A processing example in this case is shown in FIG.

  First, it is determined whether the state is power-on or return from the energy saving mode (decision 501). When it is determined that the power is turned on in the determination 501 (the result of the determination 501 is YES), a predetermined power-on process (processing 502) is performed, and when returning from the energy saving mode (the result of the determination 501 is NO), A predetermined energy saving return process (process 503) is performed.

  Next, the lamp is immediately turned on to adjust the white level (process 504). After waiting for a certain period of time until the lamp light quantity becomes stable, a predetermined white level adjustment (processing 505) is performed. Next, a predetermined black level confirmation process (process 506) is performed, and the carriage is moved to the home position (HP) (process 507).

  Next, based on the drive step amount of the scanner motor 21 when the carriage is moved to the home position in the process 507, it is checked whether or not the adjustment is made in the white level effective area (decision 508). When the result of determination 508 is YES, the white level adjustment gain value is compared with the previous result (stored gain value) to check whether there is any abnormality (determination 509).

  When the result of determination 509 is YES, the lamp 12 is turned off (process 510). Thereafter, it is determined whether there is no error in black level confirmation (determination 511). If there is no error (the result of determination 511 is YES), the scanner standby state is set (process 512). If there is an error (the result of determination 511 is NO), predetermined error processing such as error display is performed (processing 513).

  Further, when it is determined in the determination 509 that the gain error is a white level (the result of the determination 509 is NO), an error display or error processing is performed immediately by setting the number of times of the error (determination 514) ( Processing 513) and the adjustment position are set below the reference white plate WLa (processing 515), and the white level can be adjusted again (return to processing 505). At this time, the white level can be adjusted immediately by maintaining the lamp on.

  When the adjustment is made outside the white level effective area and the result of determination 508 is NO, the process proceeds to process 515, the white balance adjustment is performed again with the adjustment position set below the reference white plate WLa (return to process 505). ).

  As described above, in the present embodiment, when the power is turned on or when the energy saving mode is restored, homing is not performed, so that the processing waiting time can be shortened. In addition, since the lamp is turned on immediately after the power is turned on, the time required for the scanner standby can be shortened in consideration of the waiting time until the light quantity is stabilized.

  In addition, when the pressure plate is open, white level adjustments other than those below the reference white plate are not performed, so that invalid adjustment can be avoided. Further, since it is possible to avoid lighting the lamp in a state where the pressure plate is open, it is possible to prevent the user from directly viewing the light of the lamp.

  Further, when there is an original image on the contact glass, white level adjustment is performed on the original image, thereby avoiding invalid adjustment.

  In addition, when the gain shows an abnormality, it is possible to avoid performing shading correction using the gain. In addition, it is possible to make a precise determination by comparing the normal gain of the previous result.

  Further, it is possible to avoid the white level adjustment at a portion where the back is not white. The waiting time can be shortened by turning off the lamp after confirming that there is no gain error in white level adjustment.

  In the above-described embodiments, the case where the present invention is applied to a single document reading apparatus has been described. However, the present invention is similarly applied to an image processing apparatus having a document reading function, such as a copying machine or a multifunction peripheral. Can be applied. In that case, according to the operation mode of the main device, the mode shifts to or returns from the energy saving mode.

1 is a schematic configuration diagram illustrating an example of a schematic configuration of a document reading apparatus according to an embodiment of the present invention. FIG. 6 is a schematic configuration diagram illustrating another example of a schematic configuration of a document reading apparatus according to an embodiment of the present invention. 1 is a block diagram showing an example of a control system of a document reading apparatus according to an embodiment of the present invention. FIG. 3 is a block diagram showing a schematic configuration of a document reading unit 41. The flowchart which showed the 1st example of the process at the time of power activation or return from an energy saving mode. The flowchart which showed an example of the white level adjustment process. The flowchart which showed the 2nd example of the process at the time of power activation or return from an energy saving mode (following FIG. 8). The flowchart which showed the 2nd example of the process at the time of power-on or return from an energy saving mode (continuation of FIG. 7). The flowchart which showed the 3rd example of the process at the time of power activation or return from an energy saving mode (following FIG. 10). The flowchart which showed the 3rd example of the process at the time of power activation or return from an energy saving mode (continuation of FIG. 9). The flowchart which showed the 4th example of the process at the time of power-on or return from energy saving mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Automatic document conveyance unit 1b Image reading unit 7 Conveyance drum 10,11 Contact glass 12 Lamp 14 1st carriage 17 2nd carriage 20 CCD line image sensor 21 Scanner motor 31 CPU (central processing unit)
32 ROM (Read Only Memory)
33 RAM (Random Access Memory)
36 Input / Output Control Unit 37 Document Size Detection Sensor 38 ADF (Pressure Plate) Open / Close Sensor 41 Document Reading Unit 42 Home Position Sensor 45 Power Supply Unit 51 Timing Generation Unit 52 Analog Signal Processing Unit 53 A / D Converter BP Pressure Plate WLa, WLb, WLb '' Standard white board

Claims (4)

An original reading apparatus having at least a book reading function,
Pressure plate means for pressing the read document against the contact glass;
A first white reference image member provided on the pressure plate means for forming a reference white image for shading correction;
When the power is turned on or the energy saving mode is restored, the image of the first white reference image member is read and the shading correction reference data is created in a stop state before the carriage that moves the reading optical system is returned to the reference position. A document reading apparatus comprising control means for adjusting white level. Pressure plate opening / closing detection sensor means for detecting opening / closing of the pressure plate;
A second white reference image member provided near the contact glass and forming a shading correction reference white image;
The control means moves the carriage to the reading position of the second white reference image member when the pressure plate opening / closing detection sensor detects the opening of the pressure plate at the time of creating the shading correction reference data, 2. The document reading apparatus according to claim 1, wherein the shading correction reference data is created by reading an image of the second white reference image member. An automatic document reader provided with a pressure plate serving member that also serves as the pressure plate means and conveys the read documents placed on the document table one by one to the reading position;
A third white reference image member for forming a reference white image for shading correction is provided in the reading document conveying means,
3. The document reading apparatus according to claim 1, wherein the pressure plate combined member is provided with a fourth white reference image member for forming a reference white image for shading correction.   When the gain value after the white level adjustment is not an appropriate value, the control unit moves the carriage to the reading position of the second white reference image member, and the image of the second white reference image member. 4. The document reading apparatus according to claim 2, wherein the shading correction reference data is generated, and the white level adjustment is performed again. 5.