JP2011010198A - Image reading apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of performing shading correction in each of surface and backside reading sections disposed on the surface and backside of a document, without being affected by light from an illuminator of the other reading section.SOLUTION: Reading operation related to shading correction is performed in each of surface and backside reading sections 50 and 40, while a lamp of the other one of the two reading sections is turned off. Alternatively, reading operation related to shading correction is performed while a light intercepting member for intercepting light from the lamp of the other one of the reading sections is interposed between the surface and backside reading sections.

Description

  The present invention relates to an image reading apparatus that includes a reading unit for a front side of a document and a reading unit for a back side and can read both front and back sides of the document at a time.

  2. Description of the Related Art Some image reading apparatuses that can read both front and back sides of a document include a reading unit on each of a front side and a back side of a document to be read so that both front and back sides of the document can be read at once. The reading unit usually has an illumination unit such as a lamp or an LED array that irradiates light on a document to be read, and a light receiving unit such as a line image sensor that receives reflected light of light irradiated on the document by the illumination unit. Configured. For this reason, in the configuration in which the front side and the back side reading units are provided in close proximity to each other on both sides of the document, it is necessary to consider so as not to be affected by the light emitted from the other reading unit.

  For example, an image sensor that reads the first surface of the document and a line sensor that is arranged downstream from the reading position by the image sensor and reads the second surface of the document are provided in the middle of the document transport path. When the reading of the first side of the document is completed while the side is being read, the illumination on the first side is turned off and the light is read by a line sensor in order to reduce the influence of the light quantity fluctuation due to the turning off. There is an image reading apparatus in which density correction is performed on data read after the illumination on the first surface side is turned off among the image data on the second surface of the document (see, for example, Patent Document 1).

JP 2007-195009 A

  In a reading unit configured to receive the reflected light of the light irradiated to the document from the illuminating unit and optically read the document, unevenness in the density level of the input image due to variations in the brightness of the illuminating unit or variations in the sensitivity of the image sensor is usually ( Shading correction for correcting (shading) is performed. Shading correction is based on reading data obtained by white collection for reading the white reference plate with the illumination unit turned on and black collection for reading the white reference plate with the illumination unit turned off, or black collection is not performed. It is performed based on the read data obtained by white collection.

  As described above, since the white reference plate is read, the shading correction is performed in a state where no document is interposed between the reading unit on the front side and the reading unit on the back side. On the other hand, since the document is interposed between the reading unit on the front side and the reading unit on the back side when reading the document, the illumination of the other reading unit is more performed during the reading operation related to shading correction than when reading the document. The influence of the light received from the part increases. For this reason, the shading data shows a relatively high value (white side), and “fogging” of the document occurs.

  However, if the front side and the rear side reading units are arranged separately to reduce the influence of the light received from the illumination unit of the other reading unit, the size of the apparatus is increased. Further, in the method of correcting the influence of light received from the illumination unit of the other reading unit by performing image processing as in Patent Document 1, complicated image processing is required and it is difficult to completely remove the influence. .

  The present invention is intended to solve the above-described problem. In each of a reading unit that reads one side of a document and a reading unit that reads the other side, the influence of light from the illumination unit for the other reading unit is affected. An object of the present invention is to provide an image reading apparatus capable of performing shading correction without receiving the above.

  The gist of the present invention for achieving the object lies in the inventions of the following items.

[1] An image of the one surface of the document is arranged on one surface side of the document at the reading position, and the one surface of the document is irradiated with light from an illumination unit and reflected light is received. A first reading unit for reading;
A second reading unit that is disposed on the other side of the document and that reads the image of the other side of the document by irradiating the other side of the document with light from an illumination unit and receiving the reflected light; ,
For each of the first and second reading units, a control unit that performs a reading operation related to shading correction while turning off the illumination unit of the other reading unit,
An image reading apparatus comprising:

  In the above invention, the control unit performs the reading operation related to the shading correction for each of the first reading unit arranged on one side of the document and the second reading unit arranged on the other side. Control is performed while the illumination unit of the reading unit is turned off. The reading operation related to the shading correction includes white collection performed by turning on the illumination unit of the self reading unit and black collection performed by turning off the illumination unit of the self reading unit, but here, as the reading operation related to the shading correction, A configuration for performing both white collection and black collection or a configuration for performing only white collection may be used.

[2] An image of the one surface of the document is arranged on one side of the document at the reading position, and the one surface of the document is irradiated with light from an illumination unit and reflected light is received. A first reading unit for reading;
A second reading unit that is disposed on the other side of the document and that reads the image of the other side of the document by irradiating the other side of the document with light from an illumination unit and receiving the reflected light; ,
Switching between the first reading unit and the second reading unit between a first state in which a light blocking member that blocks light received from the illumination unit for the other reading unit is interposed and a second state in which no light is interposed Mechanism,
For each of the first and second reading units, a control unit that performs a reading operation related to shading correction by forming the first state by the switching mechanism;
An image reading apparatus comprising:

  In the above invention, the first reading unit is arranged on one side of the document, and the second reading unit is arranged on the other side. Further, switching between a first state in which a light blocking member that blocks light received from the illumination unit for the other reading unit is interposed between the first reading unit and the second reading unit, and a second state in which the light is not present. It has a mechanism. The control unit performs the reading operation related to the shading correction for each of the first and second reading units by forming a first state that is not affected by the other light by the switching mechanism. The switching mechanism may move the light shielding member, or may move at least one of the first and second reading units to form the first state.

  The reading operation related to the shading correction includes white collection performed by turning on the illumination unit of the self reading unit and black collection performed by turning off the illumination unit of the self reading unit, but here, as the reading operation related to the shading correction, A configuration for performing both white collection and black collection or a configuration for performing only white collection may be used.

[3] The switching mechanism forms the first state by moving at least one of the first and second reading units from a document reading position to a predetermined retracted position. [2] The image reading apparatus described in 1.

  In the above invention, at least one of the first reading unit and the second reading unit is moved from the reading position of the document to a predetermined retracted position, so that the other reading unit is interposed between the first reading unit and the second reading unit. A first state is formed in which a light blocking member that blocks light received from the illumination unit is interposed. For example, when the retreat position is set to a position facing the white reference plate for shading correction (white reference plate reading position), it is efficient.

[4] The image reading apparatus according to any one of [1] to [3], wherein the shading correction is black shading correction performed by turning off the illumination unit for the self reading unit.

  In the above invention, the reading operation related to the black shading correction performed by turning off the lighting unit for the reading unit is performed without being affected by the light of the lighting unit for the other reading unit. Note that the reading operation related to the white shading correction performed by turning on the lighting unit for the reading unit may be performed without being affected by the light of the lighting unit for the other reading unit. You may carry out in the state to receive.

  According to the image reading apparatus of the present invention, it is possible to perform shading correction without being affected by light from the illumination unit of the other reading unit.

1 is a block diagram illustrating a schematic configuration of a multi-function peripheral having a function of an image reading apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the structure of the original conveying apparatus which concerns on the 1st Embodiment of this invention, a back surface reading part, and a surface reading system. FIG. 3 is an explanatory diagram showing a state in which the original illumination unit is moved to the white reference plate reading position with respect to FIG. 6 is a flowchart showing an entire document reading process performed by the CPU of the multifunction peripheral according to the embodiment of the present invention. It is explanatory drawing which shows the operation | movement sequence in the 1st case of a shading collection correction | amendment. It is a flowchart which shows the surface SH collection process and back surface SH collection process in a 1st case. It is explanatory drawing which shows the process sequence in a 1st case. It is explanatory drawing which shows the operation | movement sequence in the 2nd case of a shading collection correction | amendment. It is a flowchart which shows the surface SH collection process and back surface SH collection process in a 2nd case. It is explanatory drawing which shows the process sequence in a 2nd case. It is explanatory drawing which shows the structure of the original conveying apparatus which concerns on 2nd Embodiment, a back surface reading part, and a surface reading part. It is explanatory drawing which shows the operation | movement sequence in the 3rd case of shading collection correction | amendment. It is a flowchart which shows the surface SH collection process and back surface SH collection process in a 3rd case. It is explanatory drawing which shows the process sequence in a 3rd case. It is explanatory drawing which shows the operation | movement sequence in the 4th case of shading collection correction | amendment. It is a flowchart which shows the surface SH collection process and back surface SH collection process in a 4th case. It is explanatory drawing which shows the process sequence in a 4th case.

  Hereinafter, various embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram showing a schematic configuration of a multifunction machine 10 having a function as an image reading apparatus according to the first embodiment of the present invention. The MFP 10 optically reads a document to acquire image data, and based on this image data, a copy function for printing a duplicate image of the document on a recording paper, and stores the read document image data as a file. The apparatus includes a scan function for transmitting to an external terminal, a print function for forming and outputting an image related to print data received from an external terminal such as a personal computer on a recording sheet, and the like.

  The multifunction machine 10 includes a ROM (Read Only Memory) 13, a RAM (Random Access Memory) 14, a nonvolatile memory 15, and a CPU (Central Processing Unit) 11 that controls the operation of the multifunction machine 10 via a bus 12. The document conveying device 30, the back side reading unit 40, the front side reading system 50, the operation display unit 16, the image processing unit 17, the hard disk device 18, the network communication unit 19, the printing unit 20, and the like are connected. Has been.

  Various programs and fixed data are stored in the ROM 13, and each function is realized as the multifunction machine 10 by the CPU 11 executing various processes according to these programs. The RAM 14 is used as a work memory for temporarily storing various data when the CPU 11 executes a program and an image memory for temporarily storing image data.

  The non-volatile memory 15 is a rewritable memory that retains its stored contents even when the power is turned off, and stores various setting contents (setting values) set for the multi-function device 10 and user information. .

  The operation display unit 16 has a function of displaying various operation screens and a function of receiving various operations from the user. The operation display unit 16 includes a liquid crystal display as a display, various buttons such as a mode selection button, a start button, a stop button, and a numeric keypad, and a touch panel that is provided on the surface of the liquid crystal display and detects a pressed coordinate position. Consists of.

  The image processing unit 17 performs various kinds of image processing such as image correction, rotation, enlargement / reduction, compression / expansion on the image data. The hard disk device 18 is a large-capacity nonvolatile storage device. The hard disk device 18 is used for storing read image data of a document, print data received from an external terminal, or image data obtained by rasterizing the print data.

  The network communication unit 19 performs a function of transmitting / receiving print data and various data to / from an external terminal such as a host computer through a network such as a LAN (Local Area Network).

  The printing unit 20 has a function of printing and outputting an image corresponding to input image data on a recording sheet. The printing unit 20 includes a recording paper conveyance device, a photosensitive drum, a charging device, a laser unit, a developing device, a transfer separation device, a cleaning device, and a fixing device. It is configured as a so-called laser printer that performs formation. Other image forming type printers may be used.

  FIG. 2 shows the configuration of the document conveying device 30, the back side reading unit 40, and the front side reading system 50. The document conveying device 30 separates and feeds the documents M set on the document table 31 one by one, and follows a sheet passing path H that passes through the front surface reading position F and the back surface reading position R slightly downstream of the document. The sheet is conveyed and discharged to the document discharge tray 32. The paper passing path H includes a plurality of sets of conveying rollers 33 and guide plates arranged along the paper passing path H. These transport rollers 33 are rotationally driven by a motor (not shown), and the driving / stopping of the motor is controlled by the CPU 11. The paper passing path H is formed in a horizontal U-shape. At the front side reading position F and the back side reading position R, the front side of the original is on the lower side, and the rear side of the original is on the upper side.

  The back surface reading unit 40 receives a lamp 41 for irradiating light from the back surface side to the document at the back surface reading position R, and receives the reflected light so that the back surface of the document is perpendicular to the document transport direction (sub-scanning direction). A contact-type line image sensor (CIS (Contact Image Sensor)) 42 that reads one line in the scanning direction is provided. The lamp 41 is composed of an LED array or the like. The back surface reading unit 40 repeats the reading operation in units of lines in the main scanning direction (a direction orthogonal to the sub scanning direction on the document surface) while the document conveying device 30 conveys the document in the sub scanning direction. Is read as a two-dimensional image.

  In addition, a white reference plate 43 is attached so as to face and face the back side reading unit 40. A portion of the sheet passing path H is formed between the back side reading unit 40 and the white reference plate 43, and the distance between the back side reading unit 40 and the white reference plate 43 is the maximum thickness of the original 1 planned to be read. It is set to be slightly larger than the thickness of the sheet.

  When reading the image of the back side of the document at the back side reading position R, the lamp 41 is turned on, the light is irradiated on the back side of the document, and the reflected light is received by the line image sensor 42. When the shading correction of the back side reading unit 40 is performed, the lamp 41 is turned on in a state in which no document exists between the back side reading unit 40 and the white reference plate 43, and the light is irradiated on the white reference plate 43, and the reflection thereof. Light is received by the line image sensor 42. Further, the white reference plate 43 is read with the lamp 41 turned off.

  The surface reading system 50 includes a flat box-shaped casing 53, and a document to be read is placed in an opening formed on the upper surface of the casing 53 when used as a flatbed scanner. A rectangular platen glass 51 and a transparent contact glass 52 are arranged at a predetermined distance from one end of the platen glass 51 at the surface reading position F of the document conveyed by the document conveying device 30. The platen glass 51 and the contact glass 52 are transparent and transmit light, but the other part of the casing 53 (particularly the top plate 53a) is formed of a member that does not transmit light. The platen glass 51 is a flat glass having a size that includes the maximum document size to be read. The contact glass 52 is a long and narrow rectangle that is slightly longer than the maximum length in the main scanning direction of the document at the surface reading position F and has a width of about 1 cm. It is a flat glass plate.

  A white reference plate 60 is attached to a predetermined location on the inner surface of the top plate 53a that is between the platen glass 51 and the contact glass 52 and does not transmit light.

  The surface reading system 50 is configured by a reduction optical system, and the document reading position and the line image sensor are arranged apart from each other. Specifically, a document illuminating unit 56 including a lamp 54 for irradiating the document with light through the platen glass 51 or the contact glass 52 and a mirror 55 for reflecting the reflected light L from the document in the housing 53; A moving mechanism (not shown) that moves the document illumination unit 56 back and forth along the lower surface of the platen glass 51 and an electric signal (analog image signal) that receives reflected light L from the document and that corresponds to the light intensity. Is output by the line image sensor 57, a plurality of reflection mirrors 58 that form an optical path for guiding the reflected light L reflected by the mirror 55 of the document illumination unit 56 to the line image sensor 57, and the reflection mirror 58. And a condensing lens 59 that condenses the reflected light L onto the line image sensor 57.

  The moving mechanism moves the document illumination unit 56 and the reflection mirror 58 by a motor (not shown), and the driving of the motor is controlled by the CPU 11. When reading the image of the surface of the document at the front surface reading position F, the document illumination unit 56 is moved to the document reading position S that is directly below the front surface reading position F and the contact glass 52. When the lamp 54 is turned on at the document reading position S, the light is irradiated toward the document at the surface reading position F through the contact glass 52, and the reflected light L from the document enters the mirror 55, and the reflecting mirror 58. Then, the light is received by the line image sensor 57 through the condenser lens 59 and the image on the surface of the document at the surface reading position F is read.

  When performing shading correction of the front surface reading system 50, as shown in FIG. 3, the original illumination unit 56 is moved to the white reference plate reading position W just below the center of the white reference plate 60, and the lamp 54 is turned on to emit light. Irradiated toward the white reference plate 60, the reflected light L from the white reference plate 60 enters the mirror 55, is received by the line image sensor 57 through the reflection mirror 58 and the condenser lens 59, and passes through the white reference plate 60. read. Further, the white reference plate 60 is read with the lamp 54 turned off.

  When reading a document placed on the platen glass 51, the document illumination unit 56 moves the lamp 54 in the direction of the arrow X along the lower surface of the platen glass 51 with the lamp 54 turned on. The reflected light L is received by the line image sensor 57 through the mirror 55, the reflecting mirror 58 and the condenser lens 59, whereby the image on the surface of the document is read as a two-dimensional image.

  Next, an operation when a document is transported by the document transport device 30 and both the front and back surfaces of the document are simultaneously read will be described.

  When reading the document, the CPU 11 performs unevenness (shading) of the density level of the input image due to variations in brightness of the lamps 41 and 54 of the back surface reading unit 40 and the front surface reading system 50 and variations in sensitivity of the line image sensors 42 and 57. Perform shading correction to correct. The shading correction is performed by one or both of white shading correction for correcting white side density and black shading correction for correcting black side density. The reading operation related to the white shading correction is an operation of reading the white reference plate (acquiring a signal value of the density of each pixel) with the lamp turned on, and is referred to as white collection. The reading operation related to the black shading correction is an operation of reading the white reference plate (acquiring a signal value of density of each pixel) with the lamp turned off, and is referred to as black collection.

  For example, the signal value of the density for each pixel obtained by white collection is the whitest signal value of the pixel, the signal value of the density for each pixel obtained by black collection is the blackest signal value of the pixel, and each pixel Shading correction is performed by setting a threshold value for each gradation value so that the signal range between the whitest signal value and the blackest signal value becomes the target number of gradations (for example, 256 gradations). Is called. Although it is preferable to set a threshold value for each pixel, one line is divided into a plurality of blocks and the threshold value is determined for each block in order to reduce the processing amount of data processing related to shading correction and improve the processing speed. May be. In this case, the representative value of the whitest or blackest in each block can be determined by an average value in the block or other statistical methods. One line may be one block.

  Further, the black collection may be omitted, and the shading correction may be performed using only the data obtained by the white collection. In this case, a preset value is used as the signal value corresponding to the blackest color. For example, the signal value “0” is set to the blackest. Hereinafter, the black collection and the white collection are collectively referred to as shading collection (SH collection).

  FIG. 4 shows the flow of the entire document reading process for controlling the entire sequence of shading collection operations when the document feeder 30 continuously reads a document. Here, by using the back side reading unit 40 and the front side reading system 50, both the front and back sides of each original are simultaneously read with one sheet passing, and shading is performed between the reading original and the next original (between sheets). Correction is made. That is, shading correction is performed when there is a next document and a predetermined condition for performing shading correction is satisfied. As an implementation condition, there is a reduction in the amount of light and a change in color depending on the lamp lighting time. Therefore, the passage of a predetermined time from the previous shading correction is used as a condition for performing another shading correction. Note that the shading correction performed before the start of reading the first document is also performed in accordance with the shading correction performed between sheets.

  As processing performed by the CPU 11 in connection with the shading correction, apart from the original reading overall processing of FIG. 4, a surface shading collection processing (surface SH collection processing) and a back surface reading unit for controlling operations related to shading collection of the surface reading system 50. There is a backside shading collection process (backside SH collection process) for controlling operations related to 40 shading collection, and the CPU 11 makes a request (SH collection start request) and notification (completion notice, etc.) between these processes and the entire document reading process. The operation related to the shading correction is advanced.

  The CPU 11 detects the presence or absence of a document to be read by a document presence / absence detection sensor provided in the document conveying device 30. A document to be read is transported by the document transport device 30, and during this transport, the front surface of the document is read by the front surface reading system 50 at the front surface reading position F, and at the same time the back surface of the document is scanned at the back surface reading position R. Read by. The presence / absence of the next original is detected by the original presence / absence detection sensor while the original being read is being conveyed. If there is a next original (step S101; Yes), the processing after step S102 is performed when there is no next original (step S101 ;; No) performs the processing after step S112.

  If there is a next original (step S101; Yes), the process waits for completion of reading of the front side or completion of reading of the back side (step S102; No, step S103; No). If the reading of the front surface is completed before the reading of the back surface (step S102; Yes), an SH collection start request is transmitted to the front surface SH collection processing to start the processing (step S104). Thereafter, when reading of the back surface is completed (step S105; Yes), an SH collection start request is transmitted to the back surface SH collection processing to start the processing (step S106), and the process proceeds to step S110.

  When the reading of the back surface is completed before the reading of the front surface (step S103; Yes), an SH collection start request is transmitted to the back surface SH collection processing to start the processing (step S107). Thereafter, when reading of the surface is completed (step S108; Yes), an SH collection start request is transmitted to the surface SH collection process to start the process (step S109), and the process proceeds to step S110.

  In step S110, the process waits for the completion of the shading collection process (back surface SH collection process) related to the back surface reading unit 40 (step S110; No), and completes (receives notification of completion of the back surface SH collection process) (step S110; Yes). Waiting for the completion of the shading collection process related to the reading system 50 (step S111; No), and completion (reception of the front SH collection process) (step S111; Yes), the next original is read. Accordingly, this process is executed again from step S101.

  If there is no next original (step S101; No), the front side reading or the back side reading end is waited (step S112; No, step S113; No), and the front side reading is finished before the back side reading. In this case (step S112; Yes), the lamp 54 of the front surface reading system 50 is turned off (step S114). When the reading of the back surface is completed (step S115; Yes), the lamp 41 of the back surface reading unit 40 is turned off and processing is performed. Exit.

  When the reading of the back surface is completed before the reading of the front surface (step S113; Yes), the lamp 41 of the back surface reading unit 40 is turned off (step S117), and when the reading of the front surface is completed (step S118; Yes), The lamp 54 of the surface reading system 50 is turned off (step S119), and the process is terminated.

  2 and 3, since the back surface reading position R exists downstream of the front surface reading position F, the front surface reading is always completed before the back surface reading, but the processing of FIG. The processing is also applicable to a configuration in which the back surface reading position R is upstream of the front surface reading position F.

  Next, control of operations related to the shading collection processing of the front surface reading system 50 and the back surface reading unit 40 will be described. In the following example, the shading collection performed between the original and the next original is described as an example, but the shading collection performed before the start of reading the first original is also performed according to the case between the paper. .

  In the configuration shown in FIGS. 2 and 3, when the original illumination unit 56 is at the white reference plate reading position W shown in FIG. 3, the back side reading unit 40 and the front side reading system 50 are mutually connected by the light-shielding top plate 53a. Shading collection can be performed without being affected by the light from the other lamps 41 and 54. That is, during the shading collection of the surface reading system 50 performed by moving the original illumination unit 56 to the white reference plate reading position W, there is no influence of mutual light.

  On the other hand, when the original illumination unit 56 of the front side reading system 50 is at the original reading position S shown in FIG. 2, when the light from the lamps 41 and 54 passes through the contact glass 52 and collects shading, the rear side reading unit 40 and the front side Since no original is interposed between the contact glass 52 of the reading system 50, the back surface reading unit 40 and the front surface reading system 50 are affected by the light from the other lamps 41 and 54.

  Therefore, even if the shading collection of the front side reading system 50 is completed first, the original illumination unit 56 is controlled not to return to the original reading position S until the shading collection of the back side reading unit 40 is completed. The operation at this time will be described separately for the first case and the second case.

<First case>
In the first case, the original illumination unit 56 is controlled not to return to the original reading position S until the black collection of the back side reading unit 40 is completed. FIG. 5 shows a sequence in the first case, FIG. 6 shows a flow of the front surface SH collection processing and the back surface SH collection processing in the first case, and FIG. 7 shows a processing sequence in the first case.

  When reading of the front side of the document is completed prior to reading of the back side of the document (FIG. 5 and FIG. 7: P1), a surface SH collection start request is transmitted from the entire document reading process to the surface SH collection process (FIG. 7: P2). FIG. 4: Step S104). In response to this, the surface SH collection processing turns off the lamp 54 (FIGS. 5 and 7: P3, FIG. 6: step S202), and further moves the document illumination unit 56 from the document reading position S to the white reference plate reading position W. (FIG. 6: Step S203, FIG. 7: P4), black collection is performed (FIGS. 5 and 7: P5, FIG. 6: Step S204). Further, in the surface SH collection process, the lamp 54 is turned on (FIGS. 5 and 7: P6, FIG. 6: Step S205), and white collection is performed (FIGS. 5 and 7: P7, FIG. 6: Step S206).

  On the other hand, when the reading of the back side is completed (FIG. 5 and FIG. 7: P8), a back side SH collection start request is transmitted from the whole document reading process to the back side SH collection process (FIG. 7: P9, FIG. 4: Step S106). ). In response to this, the back surface SH collection processing turns off the lamp 41 (FIGS. 5 and 7: P10, FIG. 6: Step S232), and performs black collection (FIGS. 5 and 7: P11, FIG. 6: Step S233). When the black collection is completed, a back side black collection end notification is transmitted to the front surface SH collection process (FIGS. 5 and 7: P12, FIG. 6: step S234).

  The front surface SH collection process is performed under the condition that the white collection related to the front surface reading system 50 is completed and a back surface black collection end notification is received from the back surface SH collection process (FIG. 6: Step S207; Yes). Is moved from the white reference plate reading position W to the document reading position S (FIGS. 5 and 7: P13, FIG. 6: step S208). That is, in the front surface SH collection processing, even if the white collection related to the front surface reading system 50 is completed, if the black collection of the back surface reading unit 40 is not completed, the original illumination unit 56 is held at the white reference plate reading position W. When the above condition is satisfied, the document illumination unit 56 is moved to the document reading position S.

  In the surface SH collection process, when the movement of the document illumination unit 56 to the document reading position S is completed, a notification of completion of the surface SH collection process indicating the completion is transmitted to the entire document reading process (FIG. 6: Step S209, FIG. 6). 7: P14).

  In the back side SH collection processing, after the back side black collection end notification is transmitted, the lamp 41 is turned on (FIG. 5. FIG. 7: P15, FIG. 6: step S235), and white collection related to the back side reading unit 40 is performed (FIG. 5). 5 and FIG. 7: P16, FIG. 6, step S236). When the white collection is completed, the back side SH collection process transmits a back side SH collection process completion notification to the entire document reading process (FIG. 6: Step S237, FIG. 7: P17).

  In the entire document reading process, when both the front surface SH collection process completion notification and the front surface SH collection process completion notification are received, the next original reading operation is started (FIG. 5 and FIG. 7: P18).

  As described above, the original illumination unit 56 is not moved to the original reading position S until the black collection of the back side reading unit 40 is completed. In other words, the original illumination unit 56 is retracted to the white reference plate reading position W. Since the black collection of the back surface reading unit 40 is performed, it is avoided that the light of the lamp 54 of the front surface reading system 50 affects the black collection related to the back surface reading unit 40.

  Since the influence of the light emitted from the lamp of the other reading unit is larger in the black collection than in the white collection, the first case 1 is configured not to be affected by the other lamp during the black collection. Since the original illumination unit 56 is returned to the original reading position S when the white collection of the front side reading system 50 is completed, the reading of the next original is performed as compared with the case where the completion of the white collection of the back side reading unit 40 is waited (second case). Time loss until the start can be suppressed.

<Second case>
In the second case, the original illumination unit 56 is controlled not to return to the original reading position S until both black collection and white collection of the back side reading unit 40 are completed. FIG. 8 shows a sequence in the second case, FIG. 9 shows a flow of the front surface SH collection processing and the rear surface SH collection processing in the second case, and FIG. 10 shows a processing sequence in the second case.

  When reading of the front side of the document is completed before reading of the back side of the document (FIG. 8 and FIG. 10: P1), a surface SH collection start request is transmitted from the entire document reading process to the surface SH collection process (FIG. 10: P2). FIG. 4: Step S104). In response to this, the surface SH collection processing turns off the lamp 54 (FIGS. 8 and 10: P3, FIG. 9: step S302), and further moves the document illumination unit 56 from the document reading position S to the white reference plate reading position W. (FIG. 9: Step S303, FIG. 10: P4), black collection is performed (FIGS. 8 and 10: P5, FIG. 9: Step S304). When the black collection is completed, the surface SH collection processing turns on the lamp 54 (FIGS. 8 and 10: P6, FIG. 9: Step S305), and performs white collection (FIGS. 8 and 10: P7, FIG. 9: Step S306). ).

  On the other hand, when the reading of the back side is completed (FIG. 8 and FIG. 10: P8), a back side SH collection start request is transmitted from the entire document reading process to the back side SH collection process (FIG. 10: P9, FIG. 4: Step S106). ). In response to this, the back surface SH collection processing turns off the lamp 41 (FIGS. 8 and 10: P10, FIG. 9: Step S332), and performs black collection (FIGS. 8 and 10: P11, FIG. 9: Step S333). . When the black collection is completed, the lamp 41 is turned on further (FIGS. 8 and 10: P12, FIG. 9: Step S334), white collection is performed (FIGS. 8 and 10: P13, FIG. 9: Step S335), When the white collection is completed, a back surface white collection end notification is transmitted to the front surface SH collection processing (FIGS. 8 and 10: P14, FIG. 9: step S336).

  The front surface SH collection process is performed under the condition that the white collection related to the front surface reading system 50 is completed and a back surface white collection end notification is received from the back surface SH collection process (FIG. 9: Step S307; Yes). Is moved from the white reference plate reading position W to the original reading position S (FIGS. 8 and 10: P15, FIG. 9: step S308). That is, in the front surface SH collection processing, even if the white collection related to the front surface reading system 50 is completed, if the black collection and the white collection related to the back surface reading unit 40 are not completed, the document illumination unit 56 is moved to the white reference plate reading position W. The original illumination unit 56 is moved to the original reading position S when the above condition is satisfied.

  When the movement of the document illumination unit 56 to the document reading position S is completed in the front surface SH collection process, a front surface SH collection process completion notification indicating the completion is transmitted and notified to the entire document reading process (FIG. 9: Step S309, FIG. 10: P16).

  In the back side SH collection processing, after the back side white collection end notification is transmitted, the back side SH collection processing completion notification is continuously transmitted to the entire document reading process (FIG. 9: Step S337, FIG. 10: P17). When both the front surface SH collection processing completion notification and the back surface SH collection processing completion notification are received, the whole document reading processing starts the reading operation of the next document (FIGS. 8 and 10: P18).

  As described above, the document illumination unit 56 is not moved to the document reading position S until the black collection and the white collection of the back surface reading unit 40 are completed. In other words, the document illumination unit 56 is retracted to the white reference plate reading position W. In this state, the shading collection (black collection and white collection) of the back side reading unit 40 is performed, so that the light of the lamp 54 of the front side reading system 50 affects the shading collection (black collection and white collection) related to the back side reading unit 40. It is avoided.

<Second Embodiment>
In the second embodiment, the front side of the original is read by the front side reading unit having the same configuration as that of the back side reading unit 40. Accordingly, the configuration of the original conveying apparatus is also different. Other configurations of the multifunction machine 10 are the same as those in the first embodiment, and a description thereof will be omitted. In addition, the same reference numerals are given to the same components as those in the first embodiment.

  FIG. 11 shows the configuration of the document conveying device 70, the back side reading unit 40, and the front side reading unit 80 according to the second embodiment. The document conveying device 70 separates and feeds out the documents set on the document table 71 one by one, and conveys them along a paper passing path H that passes through the front surface reading position F and the back surface reading position R slightly downstream thereof. The function of discharging the original to the original discharge tray 72 is achieved. The sheet passing path H extends downward from the inclined document table 71 along the inclination, smoothly passes in the horizontal direction after passing through the front surface reading position F and the back surface reading position R, and is substantially horizontal. It leads to the tray 72. The sheet passing path H includes a plurality of sets of conveying rollers and guide plates arranged along the sheet passing path H. The conveying rollers are driven to rotate by a motor, and the driving of the motor is controlled by the CPU 11.

  The back side reading unit 40 has the same structure as that shown in FIGS. 2 and 3 of the first embodiment, but is attached upside down in the second embodiment as compared to the first embodiment. ing. In the first embodiment, the upper side is the back side of the original and the lower side is the front side of the original in the front side reading position F and the rear side reading position R. In the second embodiment, the paper passing path H is This is because the upper side of the document is the front side and the lower side is the back side at the front side reading position F and the back side reading position R because of the straight path.

  The front side reading unit 80 is attached adjacent to the upstream side of the back side reading unit 40 by inverting the same structure as that of the back side reading unit 40 upside down. The front surface reading unit 80 is a main scanning direction in which a lamp 81 for irradiating light from the front surface side to a document at a front surface reading position F and the reflected light is received and the surface of the document is orthogonal to the transport direction (sub-scanning direction). And a contact type line image sensor 82 (CIS) for reading one line. The lamp 81 is composed of an LED array or the like. The front surface reading unit 80 repeats the reading operation in units of lines in the main scanning direction (a direction orthogonal to the sub scanning direction on the document surface) while the document conveying device 70 conveys the document in the sub scanning direction. Is read as a two-dimensional image.

  Further, a white reference plate 83 is attached so as to face and face the surface reading unit 80. A part of the sheet passing path H is formed between the front side reading unit 80 and the white reference plate 83, and the interval between the front side reading unit 80 and the white reference plate 83 is the same as in the case of the back side reading unit 40. The maximum thickness is set to be slightly larger than the thickness of one original.

  When reading the image of the surface of the document at the surface reading position F, the lamp 81 is turned on, the light is irradiated on the surface of the document, and the reflected light is received by the line image sensor 82. When the shading correction of the front surface reading unit 80 is performed, the lamp 81 is turned on in a state in which no document exists between the front surface reading unit 80 and the white reference plate 83, and the light is irradiated on the white reference plate 83 and reflected. Light is received by the line image sensor 82 (white collection). Further, black collection for reading the white reference plate 83 with the lamp 81 turned off is also performed.

  Next, an operation when a document is transported by the document transport device 70 and both the front and back surfaces of the document are simultaneously read will be described. The entire document reading process is the same as that in the first embodiment, and a description thereof will be omitted.

  In the following examples, the shading collection performed between the original and the next original will be described as an example. However, the shading correction performed before the reading of the first original is also performed according to the case of the inter-paper. .

  In the configuration shown in FIG. 11, the front side reading unit 80 and the back side reading unit 40 are arranged close to each other with the paper passing path H interposed therebetween. In this case, the back side reading unit 40 and the front side reading unit 80 are affected by the light of the other lamps 41 and 81. Therefore, control is performed such that shading collection of the reading unit is performed while the lamp of the other reading unit is turned off. The operation at this time will be described separately for a third case in which the other lamp is turned off only in the case of black collection, and a fourth case in which the other lamp is turned off for both white collection and black collection.

<Third case>
12 shows a sequence in the third case, FIG. 13 shows a flow of the front surface SH collection processing and the back surface SH collection processing in the third case, and FIG. 14 shows a processing sequence in the third case.

  When the reading of the front side of the document is completed prior to the reading of the back side of the document (FIGS. 12 and 14: P1), a surface SH collection start request is transmitted from the entire document reading process to the surface SH collection process (FIG. 14: P2). FIG. 4: Step S104). In response to this, the surface SH collection processing turns off the lamp 81 (FIGS. 12 and 14: P3, FIG. 13: step S402).

  When the reading of the back side is completed (FIG. 12 and FIG. 14: P4), a back side SH collection start request is transmitted from the entire document reading process to the back side SH collection process (FIG. 14: P5, FIG. 4: Step S106). ). In response to this, the back surface SH collection processing turns off the lamp 41 (FIGS. 12 and 14: P6, FIG. 13: step S432), and transmits a back surface lamp turn-off notification to the front surface SH collection processing (FIGS. 12 and 12). 14: P7, FIG. 13: Step S433).

  When the front surface SH collection processing receives the notification of turning off the back lamp (FIG. 13: Step S403; Yes), black collection is started (FIGS. 12 and 14: P8, FIG. 13: Step S404). A black collection end notification is transmitted to the rear surface SH collection process (FIGS. 12 and 14: P10, FIG. 13: step S405).

  In the back side SH collection processing, after the back side lamp extinction notification is transmitted, black collection is continuously performed (FIGS. 12 and 14: P9, FIG. 13: step S434). When black collection is completed, the back side black collection end notification is sent to the front side SH. It transmits with respect to a collection process (FIG. 12 and FIG. 14: P12, FIG. 13: step S435).

  In the front surface SH collection processing, the lamp 81 is turned on (FIG. 13 and Step S406; Yes) on the condition that the black collection on the front surface side is completed and the back surface black collection end notification is received (FIG. 12 and FIG. 14: P13, 13: Step S407), white collection is performed (FIGS. 12 and 14: P14, FIG. 13: Step S408). When the white collection is completed, a front surface SH collection process completion notification indicating the completion is transmitted to the entire document reading process (FIG. 13: step S409, FIG. 14: P15).

  Similarly, in the rear surface SH collection process, the lamp 41 is turned on (FIG. 13: Step S436; Yes) on the condition that the black collection on the rear surface side is completed and the front surface black collection end notification is received (FIG. 12 and FIG. 14: P16, FIG. 13: Step S437), white collection is performed (FIGS. 12 and 14: P17, FIG. 13: Step S438). When the white collection is completed, a back side SH collection process completion notification indicating the completion is transmitted to the whole document reading process and notified (FIG. 13: Step S439, FIG. 14: P18). When both the front side SH collection processing completion notification and the back side SH collection processing completion notification are received, the whole original reading process starts the reading operation of the next original (FIG. 12 and FIG. 14: P19).

  Thus, each black collection of the back surface reading unit 40 and the front surface reading unit 80 is performed in a state where the other lamps 41 and 81 are turned off (that is, both the lamps 41 and 81 are turned off). Black collection can be performed without being affected by the light of the lamps 41 and 81 of the reading unit.

  In the third case, the lamp of the other reading unit is allowed to be lit during white collection. This is because in white collection, even if the light from the other lamp is received, the influence on the collection result and shading correction is less than in black collection. Further, since the next original is read without turning off the lamps 41 and 81 after white collection, shading correction can be performed with higher accuracy without being affected by fluctuations in the amount of light due to turning off and lighting.

<4th case>
In the fourth case, both black collection and white collection are performed with the other lamp turned off. FIG. 15 shows a sequence in the fourth case, FIG. 16 shows a flow of the front surface SH collection processing and the back surface SH collection processing in the fourth case, and FIG. 17 shows a processing sequence in the fourth case.

  When scanning of the front side of the document is completed before scanning of the back side of the document (FIG. 15 and FIG. 17: P1), a front SH collection start request is transmitted from the entire document reading process to the front surface SH collection process (FIG. 17: P2). FIG. 4: Step S104). In response to this, the surface SH collection processing turns off the lamp 81 (FIGS. 15 and 17: P3, FIG. 16: step S502).

  When reading of the back side is completed (FIG. 15 and FIG. 17: P4), a back side SH collection start request is transmitted from the whole document reading process to the back side SH collection process (FIG. 17: P5, FIG. 4: Step S106). ). In response to this, the back surface SH collection processing turns off the lamp 41 (FIGS. 15 and 17: P6, FIG. 16: step S532), and transmits a back surface lamp turn-off notification to the front surface SH collection processing (FIGS. 15 and FIG. 15). 17: P7, FIG. 16: Step S533).

  When the front surface SH collection process receives a notification of turning off the back surface lamp (FIG. 16: Step S503; Yes), black collection is started (FIGS. 15 and 17: P8, FIG. 16: Step S504). That is, black collection is performed with the other (back side) lamp turned off. In the front surface SH collection processing, after completion of black collection, the completion of black collection on the back side is waited (FIG. 16: Step S505; No). That is, after waiting for the back side black collection end notification to be transmitted from the back side SH collection processing and receiving the back side black collection end notification (FIG. 16: Step S505; Yes), the lamp 81 is turned on (FIGS. 15 and 17). : P11, FIG. 16: Step S506). In this way, the front side reading lamp 81 is turned off until the other (back side) black collection is completed, so that the back side also collects black with the other (front side) lamp 81 turned off. It can be carried out.

  In the back side SH collection processing, after the back side lamp turn-off notification is transmitted, black collection is continuously performed (FIGS. 15 and 17: P9, FIG. 16: step S534). When black collection is completed, the back side black collection end notification is sent to the front side SH. It transmits with respect to a collection process (FIG. 15 and FIG. 17: P10, FIG. 16: step S535). When the black collection is completed, the process waits for the completion of the white collection on the surface (FIG. 16: Step S536; No). That is, it waits for the notification of the completion of surface white collection from the surface SH collection processing. In this manner, the back side reading side lamp 41 is kept off until the other side (front side) white collection is completed, so that the front side performs white collection with the other side (back side) lamp 41 turned off. It can be carried out.

  When the front surface SH collection process receives a back surface black collection end notification from the back surface SH collection process (FIG. 16: Step S505; Yes), the lamp 81 is turned on (FIGS. 15 and 17: P11, FIG. 16: Step S506). White collection is performed (FIGS. 15 and 17: P12, FIG. 16: step S507). When the white collection is completed, a front surface white collection end notification indicating the completion is transmitted to the back surface SH collection process (FIGS. 15 and 17: P13, FIG. 16: step S508), and the lamp 81 is turned off (FIG. 15). 17: P14, FIG. 16: Step S509), a front lamp extinction notification is transmitted to the rear surface SH collection process (FIGS. 15 and 17: P16, FIG. 16: Step S510).

  When the back surface SH collection process receives the front surface white collection end notification from the front surface SH collection process (FIGS. 15 and 17: P13, FIG. 16: Step S536; Yes), the lamp 41 is turned on (FIGS. 15 and 17: P15, FIG. 16: Step S537). Thereafter, when a notification of surface lamp extinction is further received from the surface SH collection processing (FIG. 15 and FIG. 17: P16, FIG. 16: Step S538; Yes), white collection is performed (FIGS. 15 and 17: P17, FIG. 16: Step). S539). That is, white collection on the back side is performed with the other (front side) lamp 81 turned off.

  When the back side SH collection process completes the white collection, a back side white collection end notification indicating the completion is transmitted to the front side SH collection process (FIGS. 15 and 17: P18, FIG. 16: step S5340). Further, a back surface SH collection processing completion notification is transmitted to the entire document reading processing and notified (FIG. 16: step S541, FIG. 17: P21).

  When the front surface SH collection process receives a back surface white collection end notification from the back surface SH collection process (FIG. 16: Step S511; Yes), the lamp 81 is turned on (FIGS. 15 and 17: P19, FIG. 16: Step S512). An SH collection processing completion notification is sent to the entire document reading process for notification (FIG. 16: step S513, FIG. 17: P20).

  When both the front surface SH collection processing completion notification and the back surface SH collection processing completion notification are received, the entire document reading processing starts the reading operation of the next document (FIGS. 15 and 17: P22).

  In this way, black collection and white collection of the back side reading unit 40 and the front side reading unit 80 are performed in a state where the other lamps 41 and 81 are turned off. Black collection and white collection can be performed without being affected.

  The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration is not limited to that shown in the embodiment, and there are changes and additions within the scope of the present invention. Are also included in the present invention.

  For example, in the first embodiment, by moving the original illumination unit 56 to the white reference plate reading position W, the top plate 53a becomes a light shielding member, and the back side reading unit 40 and the front side reading system 50 are mutually connected to the other lamp. The state where light is not received is formed, but the state where light is blocked by the light blocking member may be formed by other methods. For example, if the top plate 53a is a light shielding member and the back surface reading unit 40 and the front surface reading system 50 are in a state where they do not receive the light of the other lamp, a place other than the white reference plate reading position W is used. The document illumination unit 56 may be moved as the retracted position. Moreover, the structure which moves a light-shielding member may be sufficient. For example, a rear surface reading unit is provided by providing a light shielding plate that is displaced between a light shielding position that covers the contact glass 52 and a retracted position beside the contact glass 52 (a position that does not cover the contact glass 52) and moving the light shielding plate to the light shielding position. 40 and the surface reading system 50 may be configured to form a state in which the light of the other lamp is not received.

  In the first embodiment, the surface reading system 50 is configured as a reduction optical system including the document illumination unit 56, the reflection mirror 58, the condensing lens 59, and the like. However, a unity optical system such as CIS and a lamp are integrated. The module may be a module such as the front surface reading unit 80, and the module may be moved to the document reading position S, the white reference plate reading position W, or the like.

  Further, in the embodiment, the white reference plates 43 and 83 are fixedly arranged at positions facing the back side reading unit 40 and the front side reading unit 80. However, the white reference plate is placed at the reading position when collecting shading, and other when reading the document. It may be configured to move so as to evacuate.

  The correction contents performed based on the data collected by the shading collection are not limited to those exemplified in the embodiment.

  In the embodiment, the multifunction machine 10 has been described as an example. However, an apparatus that does not include a printing unit or the like may be used, and any image reading apparatus that can simultaneously read both sides of a document may be used. For example, a facsimile device or a scanner device may be used.

10 ... Machine 11 ... CPU
12 ... Bus 13 ... ROM
14 ... RAM
DESCRIPTION OF SYMBOLS 15 ... Non-volatile memory 16 ... Operation display part 17 ... Image processing part 18 ... Hard disk apparatus 19 ... Network communication part 20 ... Printing part 30 ... Original conveying apparatus 31 ... Original stand 32 ... Original paper discharge tray 33 ... Conveying roller 40 ... Back side reading Part 41 ... Lamp 42 ... Line image sensor 43 ... White reference plate 50 ... Surface reading system 51 ... Platen glass 52 ... Contact glass 53 ... Housing 53a ... Top plate 54 ... Lamp 55 ... Mirror 56 ... Document illumination part 57 ... Line image Sensor 58 ... Reflecting mirror 59 ... Condensing lens 60 ... White reference plate 70 ... Document feeder 71 ... Document table 72 ... Document discharge tray 80 ... Front reading unit 81 ... Lamp 82 ... Line image sensor 83 ... White reference plate F ... Front side reading position H ... Passing path M ... Original L ... Reflected light R ... Back side reading position S ... Original reading position W ... White base Plate reading position X ... moving direction of the original illumination unit

Claims (4)

A first reading unit which is disposed on one side of a document at a reading position, reads an image on the one side of the document by irradiating the one surface of the document with light from an illumination unit and receiving reflected light. A reading unit;
A second reading unit that is disposed on the other side of the document and that reads the image of the other side of the document by irradiating the other side of the document with light from an illumination unit and receiving the reflected light; ,
For each of the first and second reading units, a control unit that performs a reading operation related to shading correction while turning off the illumination unit of the other reading unit,
An image reading apparatus comprising: A first reading unit which is disposed on one side of a document at a reading position, reads an image on the one side of the document by irradiating the one surface of the document with light from an illumination unit and receiving reflected light. A reading unit;
A second reading unit that is disposed on the other side of the document and that reads the image of the other side of the document by irradiating the other side of the document with light from an illumination unit and receiving the reflected light; ,
Switching between the first reading unit and the second reading unit between a first state in which a light blocking member that blocks light received from the illumination unit for the other reading unit is interposed and a second state in which no light is interposed Mechanism,
For each of the first and second reading units, a control unit that performs a reading operation related to shading correction by forming the first state by the switching mechanism;
An image reading apparatus comprising: The said switching mechanism forms said 1st state by moving at least one of said 1st, 2nd reading part from the reading position of a document to a predetermined evacuation position, The said 1st state is formed. Image reading device. The image reading apparatus according to any one of claims 1 to 3, wherein the shading correction is black shading correction performed by turning off an illumination unit for the self-reading unit.

Images