JP2018107572A - Image reading device, image formation apparatus, control program and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device, an image formation apparatus, a control program and a control method which can decide the document size without turning a document pressing cover into the closed state.SOLUTION: An image reading device 10 includes a CPU. The CPU detects the light amount for each of a plurality of divided regions set in the main-scanning direction for each prescribed time when a document pressing cover 18 starts to be closed on the basis of the output of an opening/closing sensor 164, calculates the ratio of the minimum value to the maximum value of the light amount in each divided region as the result of the prescribed frequency of sampling, decides the size in the main-scanning direction on the basis of the calculated ratio, decides the size in the sub-scanning direction on the basis of the output of two sub-scanning sensors, and decides the document size on the basis of the size in the main-scanning direction and the size in the sub-scanning direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image reading apparatus, an image forming apparatus, a control program, and a control method, and more particularly to an image reading apparatus, an image forming apparatus, a control program, and a control method for reading a document.

  An example of this type of background art is disclosed in Patent Document 1. In the image reading apparatus of Patent Document 1, the document illumination lamp is turned on simultaneously with the start of closing the pressure plate, and the document size detection process is performed until the pressure plate is in the “closed” state. In the document size detection, the reference white plate and the document are sampled at regular intervals. The document width is detected by referring to the detection point in the main scanning direction. Specifically, at each sampling interval, if the reading value (light quantity) at each detection point exceeds the threshold level calculated from the white level of the reference white plate, it is determined that there is a document and is lower. In this case, it is determined that there is no document. To determine the document size, first, the document presence / absence determination history of each detection point is searched, and it is determined that there is no document at the detection point that has changed from “no document” to “present”. Then, the document size is determined using the maximum width of the detection point where the document is finally present. However, the sub-scanning size is determined by whether or not the presence of a document is detected by the photo sensor.

JP 2008-263292 A [H04N 1/04, H04N 1/10, H04N 1/107, H04N 1/00, G06T 1/00]

  However, in the image reading apparatus of Patent Document 1, when the pressure plate is in the “closed” state, the document illumination lamp is turned off to determine the document size, so that the pressure plate needs to be closed. Therefore, the document size of a thick document such as a book document cannot be automatically detected. Further, since the threshold level is determined by a predetermined ratio (70%) of the amount of light (white level) of the reference white plate, there remains a problem in detecting the document size of a black white original.

  Therefore, a main object of the present invention is to provide a novel image reading apparatus, image forming apparatus, control program, and control method.

  Another object of the present invention is to provide an image reading apparatus, an image forming apparatus, a control program, and a control method capable of detecting the document size without closing the document pressing cover.

  A first invention is an image reading apparatus including a document pressing cover that covers a document placed on a transparent plate, and a reading unit that includes at least an image reading element, the first size detection unit, and a cover detection unit A light amount detection unit, a ratio calculation unit, a second size detection unit, and a document size determination unit. The first size detection unit detects a first size of the document in the sub-scanning direction of the reading unit. The cover detection unit detects that at least the document pressing cover is moving in the closing direction. The light amount detection unit detects the light amount of each of the plurality of divided regions in the main scanning direction at predetermined time intervals in response to the detection of the document pressing cover moving in the closing direction by the cover detection unit. The ratio calculation unit calculates a light amount ratio based on the maximum value and the minimum value of each light amount of the divided areas detected by the light amount detection unit. The second size detection unit detects the second size of the document in the main scanning direction of the reading unit based on the calculation result of the ratio calculation unit. The document size determination unit determines the document size based on the detection result of the first size detection unit and the detection result of the second size detection unit.

  According to the first aspect of the invention, when it is detected that the document pressing cover is moving in the closing direction, the light amount of each divided area set in the scanning area in the main scanning direction is detected every predetermined time. Since the document size is determined based on the size in the main scanning direction and the size in the sub-scanning direction that are detected based on the ratio of the minimum value to the maximum value of the light amount, the document size can be adjusted even if the document pressing cover is not closed. Can be detected.

  The second invention is dependent on the first invention and further includes a presence / absence determining unit. The presence / absence determining unit determines the presence / absence of a document in each divided region based on whether the ratio calculated by the ratio calculating unit exceeds a predetermined threshold. For example, when the ratio of the minimum value to the maximum value is calculated, a large ratio means that the maximum value and the minimum value are approximated, and therefore it is determined that there is a document for the area. . On the other hand, when the ratio is small, it means that the difference between the maximum value and the minimum value is large. Therefore, it is determined that there is no document in the area. The second size detection unit detects the second size based on the divided area determined by the presence / absence determination unit that the document is present.

  According to the second invention, it is possible to determine the presence or absence of a document for each divided area, and to determine the size in the main scanning direction according to the divided area determined to have a document.

  A third invention is dependent on the second invention and further includes a recalculation unit. The recalculation unit recalculates the threshold value from the maximum value and the minimum value of the light amount ratio in all the divided areas.

  According to the third aspect, since the threshold value is recalculated, it is possible to correctly determine the document size even for a document whose light quantity ratio is reduced, such as thin paper.

  The fourth invention is dependent on any one of the first to third inventions, and the means for determining presence / absence of each area places a document in the divided area when the light quantity of the divided area continuously increases a plurality of times. It is determined that it is not placed.

  According to the fourth aspect of the present invention, it can be determined that there is no document for the area even when the light quantity continuously increases a plurality of times.

  A fifth invention is dependent on any one of the first to fourth inventions, and further includes a non-placement determining unit. The non-placement determining unit determines whether the document is not placed on the transparent plate according to whether the ratio calculated by the ratio calculating unit satisfies a predetermined condition. When the non-placement determining unit does not determine that the document is not placed on the transparent plate, the second size detecting unit and the document size determining unit are caused to execute processing. That is, when it is determined that the document is not placed on the transparent plate, the processes of the second size detection unit and the document size determination unit are not executed.

  According to the fifth invention, when the document is not placed on the transparent plate, the processing by the second size detection unit and the document size determination unit can be omitted. That is, useless processing can be omitted.

  The sixth invention is dependent on the first to fifth inventions, and the divided areas are changed between when the document size is determined as the AB size and when the document size is determined as the inch size.

  According to the sixth aspect of the invention, when reading originals of different sizes, the divided area is changed, so that the original size can be determined correctly.

  A seventh invention is an image reading apparatus including a document pressing cover that covers a document placed on a transparent plate, and a reading unit that includes at least an image reading element, a cover detection unit, a light amount detection unit, A ratio calculation unit and a placement determination unit are provided. The cover detection unit detects that at least the document pressing cover is moving in the closing direction. The light amount detection unit detects the light amount of each of the plurality of divided regions in the main scanning direction at predetermined time intervals in response to the detection of the document pressing cover moving in the closing direction by the cover detection unit. The ratio calculation unit calculates a light amount ratio based on the maximum value and the minimum value of each light amount of the divided areas detected by the light amount detection unit. The placement determination unit determines whether or not the document is placed on the transparent plate based on the calculation result of the ratio calculation unit.

  According to the seventh aspect, it is possible to determine whether or not the document is placed on the transparent plate based on the ratio of the light amount for each of the divided areas without closing the document pressing cover. .

  An eighth invention is an image forming apparatus including the image reading device according to any one of the first to seventh inventions.

  A ninth invention is a control program to be executed by an image reading apparatus including a document pressing cover that covers a document placed on a transparent plate and a reading unit that includes at least an image reading element, and a processor of the image reading apparatus In addition, a first size detecting step for detecting the first size of the document in the sub-scanning direction of the reading unit, a cover detecting step for detecting that at least the document pressing cover is moving in the closing direction, and a document pressing in the cover detecting step In response to detecting that the cover is moving in the closing direction, a light amount detection step for detecting the light amount of each of the plurality of divided regions in the main scanning direction at predetermined times, and the divided region detected in the light amount detection step The ratio calculation step for calculating the ratio of the light quantity based on the maximum value and the minimum value of each light quantity, and the calculation of the ratio calculation step Based on the result, the second size detection step for detecting the second size of the document in the main scanning direction of the reading unit, the detection result of the first size detection step, and the detection result of the second size detection step, the document size This is a control program for executing a document size determination unit for determining the document size.

  A tenth aspect of the invention is a method for controlling an image reading apparatus including a document pressing cover that covers a document placed on a transparent plate, and a reading unit including at least an image reading element. Detecting a first size of the document in the scanning direction; (b) detecting at least that the document pressing cover is moving in the closing direction; and (c) moving the document pressing cover in the cover detecting unit in the closing direction. Detecting the light quantity of each of the plurality of divided areas in the main scanning direction at predetermined time intervals, and (d) detecting the maximum light quantity of each of the divided areas detected in the light quantity detecting step. A step of calculating a ratio of light quantity based on the minimum value and (e) a second size of the document in the main scanning direction of the reading unit based on the calculation result of the ratio calculation step. The and detecting, determining the document size based on the detection result of (f) the detection result and the second size detecting step of the first size detecting step, a control method.

  In the eighth to tenth inventions, similarly to the first invention, the document size can be detected without the document pressing cover being closed.

  According to the present invention, the document size can be detected without closing the document pressing cover.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

FIG. 1 is a schematic view showing the internal structure of a part of a multifunction machine according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of the electrical configuration of the multifunction machine shown in FIG. FIG. 3 is a top view of the image reading apparatus viewed from above with the document pressing cover removed. 4A is an illustrative view showing an example of an open / close sensor when the document pressing cover is in an open state, and FIG. 4B is an illustrative view showing an example of an opening / closing sensor when the document pressing cover is in a closed state. (C) is a top view of the open / close sensor as viewed from above. FIG. 5 is a schematic diagram showing the internal structure of the document pressing cover and the image reading apparatus of the first embodiment. FIG. 6 is a schematic diagram showing the internal structure of the document pressing cover and the image reading apparatus of the first embodiment. FIG. 7A is an illustrative view showing a plurality of areas set in all scanning areas in the main scanning direction when determining an AB-size original size, and FIG. 7B shows an AB-size original size. It is an illustration figure which shows the judgment table in the case of determining. FIG. 8 is a graph showing the light quantity ratio of each area when determining the document size of a plain paper document. FIG. 9 is a graph showing the light quantity ratio of each region when determining the document size of a thin paper document. FIG. 10 is a graph showing the light quantity ratio of each region when determining the document size of a document in which white characters are printed on a solid black. FIG. 11 is an illustrative view showing one example of a memory map of the RAM shown in FIG. FIG. 12 is a flowchart showing a part of the CPU size determination processing shown in FIG. FIG. 13 is another part of the CPU size determination process shown in FIG. 2, and is a flowchart subsequent to FIG. FIG. 14A is an illustrative view showing a plurality of areas set in the entire scanning area in the main scanning direction when an inch-size document size is determined, and FIG. 14B is an inch-size document size. It is an illustration figure which shows the judgment table in the case of determining. FIG. 15 shows another part of the CPU size determination process in the third embodiment, and is a flowchart subsequent to FIG.

[First embodiment]
FIG. 1 is an illustrative view showing an external configuration of an image forming apparatus according to a first embodiment of the present invention. With reference to FIG. 1, an outline of the image forming apparatus will be described to the extent necessary for understanding the present invention. FIG. 1 illustrates a multifunction peripheral (MFP) 100 having a copying function, a printer function, a scanner function, a facsimile function, and the like as an example of an image forming apparatus. However, it should be pointed out in advance that the present invention can be applied to the image reading apparatus 10 (scanner function) or any image forming apparatus including at least the image reading apparatus 10.

  As shown in FIG. 1, the multifunction device 100 includes an image reading device 10, and the image reading device 10 is disposed above the multifunction device main body 12. The image reading apparatus 10 includes an original placing table (original table glass) 14a and an SPF glass 14b formed of a transparent material. A document pressing cover 18 is attached above the document placing table 14a and the SPF glass 14b via a hinge 16 (see FIG. 6) and the like so as to be freely opened and closed. 1, the hinge 16 connects the document pressing cover 18 to the image reading device 10 so that the document pressing cover 18 can be opened and closed at the back end of the image reading device 10. The document pressing cover 18 automatically feeds documents placed on the document placing tray 20 one by one with respect to the image reading position 22 (position where the SPF glass 14b is provided). Device) 24 is provided. However, the ADF 24 may not be provided.

  An operation unit 162 (not shown in FIG. 1) such as a touch panel and operation buttons for receiving an input operation by the user is provided on the front side (the front side in FIG. 1) of the document placing table 14a. An opening / closing sensor 164 for detecting the opening / closing of the document pressing cover 18 is provided on the left side of the left hinge 16 when the image reading apparatus 10 is viewed from the front side. (See also FIGS. 5 and 6).

  Further, the image reading device 10 is provided with an image reading unit 26. The image reading unit 26 includes a light source 260, a plurality of mirrors 262, a reflector 264, an imaging lens 266, a line sensor 268, and the like. However, the light source 260, the plurality of mirrors 262, and the reflector 264 constitute a scanning unit 270.

  The light source 260 is an LED, a halogen lamp, a xenon lamp, or the like, and is formed in a bar shape long in the arrangement direction (main scanning direction) of the line sensors 268, and illuminates the document.

  Each of the plurality of mirrors 262 reflects the reflected light image from the original illuminated by the light source 260 in a predetermined direction. The reflector 264 collects light output (exposed) from the light source 260 on the document.

  When reading a document placed on the document table 14a, the scanning unit 270 is moved in the sub-scanning direction at a predetermined speed by a scan motor. Further, when reading the original placed on the original placement tray 20 by the ADF 24, the scanning unit 270 is stopped below the SPF glass 14b.

  The image reading unit 26 exposes the document surface with a light source 260 and guides reflected light reflected from the document surface to the imaging lens 266 by a plurality of mirrors 262. The reflected light is imaged on the light receiving element of the line sensor 268 by the imaging lens 266. The line sensor 268 detects the brightness and chromaticity of the reflected light imaged on the light receiving element, and generates image data based on the image on the document surface. As the line sensor 268, an imaging device such as a charge coupled device (CCD) or a contact image sensor (CIS) is used. However, the line sensor 268 includes an R line sensor, a G line sensor, and a B line sensor.

  A control unit 28 and an image forming unit 30 are provided inside the multifunction machine main body 12. The control unit 28 includes a CPU 150, memories (154, 156, 158) and the like (see FIG. 2), and transmits a control signal to each unit of the multifunction device 100 in response to an input operation to the operation unit 162 such as a touch panel. Then, the MFP 100 is caused to execute various operations.

  The image forming unit 30 includes an exposure unit 32, a developing roller 34, a photosensitive drum 36, a cleaner unit 38, a charger 40, an intermediate transfer belt unit 42, a transfer roller (secondary transfer roller) 44, a fixing unit 46, and the like. An image is formed on a sheet (recording sheet) conveyed from the sheet feeding cassette 48 or the manual sheet feeding cassette 50, and the sheet on which the image has been formed is discharged to a sheet discharge tray 52. As image data for forming an image on a sheet, image data read by the image reading unit 26, image data transmitted from an external computer, or the like is used.

  Note that the image data handled in the multifunction peripheral 100 corresponds to four color images of black (K), cyan (C), magenta (M), and yellow (Y). For this reason, each of the developing roller 34, the photosensitive drum 36, the cleaner unit 38, and the charger 40 is provided so as to form four types of latent images corresponding to the respective colors, thereby providing four image stations. Composed. Further, the photosensitive drum 36, the cleaner unit 38, and the charger 40 are unitized, and a process unit is configured by these units. That is, the image forming unit 30 is provided with four process units 35 each including a photosensitive drum 36, a cleaner unit 38, a charger 40, and the like. Each of the process units 35 can be individually attached and detached from the front side of the multifunction machine 100.

  The photosensitive drum 36 is an image carrier in which a photosensitive layer is formed on the surface of a cylindrical substrate having conductivity. The charger 40 applies a predetermined potential (for example, −600 V) to the surface of the photosensitive drum 36. ). For example, a roller-type charger (charging roller) 40 is used. Further, the exposure unit 32 is configured as a laser scanning unit (LSU) including a laser emitting portion and a reflection mirror, and exposes the surface of the charged photosensitive drum 36 so that an electrostatic latent image corresponding to image data is obtained. An image is formed on the surface of the photosensitive drum 36. The developing roller 34 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 36 with toner of four colors (YMCK). The cleaner unit 38 removes toner remaining on the surface of the photosensitive drum 36 after development and image transfer with a cleaning blade, and conveys the removed toner to a waste toner box.

  The charger 40 has the same axial length as the photoconductor drum 36, and the charger 40 and the photoconductor drum 36 are arranged in parallel so that their outer peripheral surfaces are in contact with each other. Rotate at the same peripheral speed. The cleaning roller 72 is disposed so as to contact the outer peripheral surface of the charger 40 at a position opposite to the photosensitive drum 36. The cleaning roller 72 includes a cylindrical metal shaft and an elastic foam (sponge layer) covering the outer peripheral surface thereof, and removes foreign matters such as toner adhering to the outer peripheral surface of the charger 40.

  The intermediate transfer belt unit 42 includes an intermediate transfer belt 54, a drive roller 56, a driven roller 58, four intermediate transfer rollers 60, and the like, and is disposed above the photosensitive drum 36. The intermediate transfer belt 54 is provided so as to be in contact with each photosensitive drum 36, and the toner images of the respective colors formed on the respective photosensitive drums 36 are sequentially superimposed on the intermediate transfer belt 54 using the intermediate transfer roller 60. As a result, a multicolor toner image is formed on the intermediate transfer belt 54. Further, a transfer roller 44 is disposed in the vicinity of the driving roller 56, and the toner formed on the intermediate transfer belt 54 by passing the sheet through the nip area between the intermediate transfer belt 54 and the transfer roller 44. The image is transferred to the paper.

  The fixing unit 46 includes a heat roller 62 and a pressure roller 64 and is disposed above the transfer roller 44. The heat roller 62 is set to have a predetermined fixing temperature. When the sheet passes through the nip area between the heat roller 62 and the pressure roller 64, the toner image transferred to the sheet is melted and melted. The toner image is heat-fixed on the sheet by pressure contact.

  In the multifunction machine main body 12, the paper placed in the paper feed cassette 48 or the manual paper feed cassette 50 is sent to the paper discharge tray 52 via the registration roller 68, the transfer roller 44 and the fixing unit 46. The first paper transport path R1 is formed. In addition, when performing duplex printing on a sheet, the sheet after completion of single-sided printing and passing through the fixing unit 46 is returned to the first sheet conveyance path R1 on the upstream side of the transfer roller 44 in the sheet conveyance direction. The second paper transport path R2 is formed. A plurality of transport rollers 66 for transporting paper are appropriately provided in the first paper transport path R1 and the second paper transport path R2.

  When single-sided printing is performed in the multifunction machine main body 12, the sheets placed on the sheet feeding cassette 48 or the manual sheet feeding cassette 50 are guided to the first sheet conveyance path R1 one by one by the pickup roller 70, and the conveyance roller 66. Is conveyed to the registration roller 68. Then, the registration roller 68 conveys the sheet to the transfer roller 44 at a timing when the leading edge of the sheet and the leading edge of the image information on the intermediate transfer belt 54 are aligned, and the toner image is transferred onto the sheet. Thereafter, when the toner passes through the fixing unit 46, the unfixed toner on the paper is melted and fixed by heat, and the paper is discharged onto the paper discharge tray 52 through a conveyance roller (paper discharge roller) 66.

  On the other hand, when performing double-sided printing, when the trailing edge of the paper that has passed through the fixing unit 46 after single-sided printing has reached the paper discharge roller 66 near the paper discharge tray 52, the paper discharge roller 66 is reversed. By rotating, the sheet runs backward and is guided to the second sheet conveyance path R2. The paper guided to the second paper transport path R2 is transported through the second paper transport path R2 by the transport roller 66, and is guided to the first paper transport path R1 on the upstream side of the registration roller 68 in the paper transport direction. At this time, the front and back sides of the sheet are reversed, and thereafter, the sheet passes through the transfer roller 44 and the fixing unit 46, whereby printing is performed on the back side of the sheet.

  FIG. 2 is a block diagram illustrating an example of an electrical configuration of the multifunction peripheral 100 illustrated in FIG. As illustrated in FIG. 2, the multifunction peripheral 100 includes a CPU 150, and the CPU 150 is connected to a ROM 154, a RAM 156, an HDD 158, and an image signal processing circuit 160 via an internal bus 152. Further, the image reading device 10, the image forming unit 30, and the operation unit 162 are connected to the internal bus 152 of the control unit 28.

  The CPU 150 governs overall control of the multifunction peripheral 100. The ROM 154 stores default values for the activation program of the multifunction peripheral 100 and various information. The RAM 156 is used as a working area and a buffer area for the CPU 150. The HDD 158 is a main storage device of the multifunction peripheral 100, and stores image data read by the image reading unit 26, image data transmitted from an external computer, and the like. However, the image data read by the image reading unit 26 (image data based on the output of the line sensor 268) is subjected to predetermined processing in the image signal processing circuit 160.

  The image signal processing circuit 160 amplifies the RGB color image signals output from the line sensor 268, performs A / D (analog / digital) conversion, and performs shading on the image data converted from analog signals to digital signals. Make corrections. That is, black shading correction using black correction data is executed, and white shading correction using white correction data is executed.

  Further, the image signal processing circuit 160 performs processing (post-processing) such as color conversion of the image data subjected to the shading correction from RGB to YMCK data and adjusting the color tone, and outputs the processed data to the CPU 150. The CPU 150 stores the image data output from the image signal processing circuit 160 in the HDD 158 or controls the image forming unit 30 to print a corresponding image on recording paper (paper).

  The image reading apparatus 10 includes an open / close sensor 164, a motor drive circuit 204, a lighting control circuit 208, a first sub-scan sensor 230, a second sub-scan sensor 232, and a line sensor 268. The motor drive circuit 204, the lighting control circuit 208, the first sub-scanning sensor 230, the second sub-scanning sensor 232, and the line sensor 268 are connected to the CPU 150 via the internal bus 152. Further, the image reading apparatus 10 includes a scanner motor 206 and a light source 260, the scanner motor 206 is connected to the motor drive circuit 204, and the light source 260 is connected to the lighting control circuit 208.

  However, since the CPU 150 uses the RAM 156 as a buffer area and a work area to control the entire multifunction peripheral 100, at least the CPU 150 and the RAM 156 of the control unit 28 are also included in the image reading apparatus 10.

  The motor driving circuit 204 drives a scanner motor 206 for moving the scanning unit 270 included in the image reading unit 26 in the sub-scanning direction (left and right direction in FIG. 1) under the instruction of the CPU 150. The lighting control circuit 208 controls lighting and extinguishing of the light source 260 under the instruction of the CPU 150.

  The first sub-scanning sensor 230 is a sensor for detecting the document size in the sub-scanning direction, and is a reflection type photosensor including a light emitting unit and a light receiving unit. The second sub-scanning sensor 232 is also a sensor for detecting the document size in the sub-scanning direction, and is a reflection type photosensor including a light emitting unit and a light receiving unit. In the first embodiment, the first sub-scanning sensor 230 and the second sub-scanning sensor 232 are used when detecting the document sizes of AB and inch sizes.

  FIG. 3 is a schematic top view of the image reading apparatus 10 as viewed from directly above. The image reading apparatus 10 detects the size of the document placed on the document placement table 14a in the main scanning direction (FIG. 3: a direction orthogonal to the sheet conveyance direction) based on the image data output from the line sensor 268, and The size in the sub-scanning direction (FIG. 3: a direction parallel to the paper conveyance direction) is detected based on the output of the first sub-scanning sensor 230 or the second sub-scanning sensor 232.

  As shown in FIG. 3, the first sub-scanning sensor 230 and the second sub-scanning sensor 232 are the inner bottom surface of the housing 10 a that encloses the image reading unit 26 of the image reading device 10 (the surface facing the document placing table 14 a). Is provided.

  The method for detecting the document size will be described in detail later.

  The line sensor 268 detects the brightness and chromaticity of the reflected light imaged on the light receiving element under the instruction of the CPU 150, generates image data based on the image on the document surface, and outputs the image data to the image signal processing circuit 160. .

  In accordance with an instruction from the CPU 150, the image forming unit 30 prints an image corresponding to the image data on recording paper (paper) or the like as described above. The operation unit 162 includes a touch panel, operation buttons, and the like, and gives an operation signal (operation data) according to a user operation to the CPU 150.

  As described above, the open / close sensor 164 is a sensor for detecting the open / closed state of the document pressing cover 18 and includes the actuator 164a and the optical sensor 164b. However, in the first embodiment, the beginning of closing of the document pressing cover 18 (movement in the closing direction) is also detected based on the output of the open / close sensor 164.

  4A, 4B, and 4C are schematic diagrams illustrating the configuration of the open / close sensor 164. FIG. As shown in FIGS. 4A and 4B, the actuator 164 a is moved up and down in accordance with the opening and closing of the document pressing cover 18. Further, as shown in FIG. 4C, the optical sensor 164b is formed in a shape in which the U-shape is rotated 90 degrees clockwise when viewed from above (viewed from above in the moving direction of the actuator 164a). Among the two sides, the light emitting unit 1640 is provided on one side, and the light receiving unit 1642 is provided on the other side.

  When the document pressing cover 18 is opened (opened state), as shown in FIG. 4A, the actuator 164a is moved upward, so that the light output from the light emitting unit 1640 of the optical sensor 164b is received by the light receiving unit. 1642 is received. In the first embodiment, in order to determine whether or not the document pressing cover 18 has started to close, the amount of light received by the light receiving unit 1642 in the open state is measured in advance.

  On the other hand, when the document pressing cover 18 is closed (closed state), as shown in FIG. 4B, the actuator 164a is pressed downward by the document pressing cover 18, so that the light emitting portion of the optical sensor 164b. The light output from 1640 is blocked by the actuator 164a and is not received by the light receiving unit 1642, or the amount of received light is reduced.

  However, when the actuator 164a is moved, the amount of light received by the light receiving unit 1642 of the light output from the light emitting unit 1640 changes. For this reason, when the amount of received light begins to decrease after the document pressing cover 18 is opened, it can be detected that the document pressing cover 18 has started to close. When the amount of received light is equal to or less than the predetermined amount, it is detected that the document pressing cover 18 is closed.

  FIG. 5 is an illustrative view showing a schematic configuration of the image reading apparatus 10 in a state where the document pressing cover 18 is closed. FIG. 6 is an illustrative view showing a schematic configuration of the image reading apparatus 10 in a state where the document pressing cover 18 is opened.

  In such a multifunction machine 100, for example, the user opens the document pressing cover 18 from the closed state, places the document on the document placing table 14a, closes the document pressing cover 18 from the opened state, and issues a print instruction. . In the multifunction device 100, when the document pressing cover 18 is closed, the document size is automatically detected based on the output value of the line sensor 268 and the output values of the first sub-scanning sensor 230 and the second sub-scanning sensor 232. Is done.

  However, the output value of the line sensor 268 is an R signal, a G signal, and a B signal output from each of the R line sensor, the G line sensor, and the B line sensor.

  For example, in the conventional method, when the document pressing cover 18 starts to close, the light source 260 is turned on, and the document size is determined based on the output of the line sensor 268 from the start of closing until the document pressing cover 18 is closed. If is not closed, the document size cannot be determined. Therefore, when a thick document such as a book is placed on the document placing table 14a, an error occurs because the document pressing cover 18 is not closed.

  Therefore, in the first embodiment, the document size can be determined even when the document pressing cover 18 starts to close.

  Briefly, when the document pressing cover 18 is opened, an approximate document size is first detected based on the outputs of the first sub-scanning sensor 230 and the second sub-scanning sensor 232. Next, when it is detected that the document pressing cover 18 has started to be closed, the light source 260 is turned on, and the respective light amounts of a plurality of regions (partial regions or divided regions) set in the entire scanning region of the light source 260 in the main scanning direction. The presence / absence of the document (inside / outside of the document area) is determined from the change in the light intensity and the light quantity ratio. Then, the document size is determined (detected) based on the determination result of the main scanning and the detection results of the first sub-scanning sensor 230 and the second sub-scanning sensor 232.

  However, the light amount of the area means a total value or an average value (or a representative value such as a maximum value) of the light quantities of all the pixels included in the area.

  FIG. 7A is an illustrative view showing a plurality of areas set in all scanning areas in the main scanning direction of the light source 260 when detecting an AB-size original size. As shown in FIG. 7A, when an AB-size document size is detected, six areas (area 1, area 2, area 3, area 4, area 5, and area 6) are set. . As shown in FIG. 7A, the areas 1 to 6 are set in order from the back side of the image reading apparatus 10 (multifunction apparatus 100).

  However, as shown in FIG. 3, when the document placing table 14a is viewed from above, the document is placed so that the upper left vertex of the document placing table 14a is the reference position and the corner of the document is aligned with the reference position. The areas 1 to 6 are set on the assumption that they are placed.

  Area 1 is set to detect the document sizes of A5R, B5R, and A4. Area 2 is set to detect the document sizes of A5, A5R, and A4R. Area 3 is provided for detecting the document sizes of B5 and B4. Regions 4 and 5 are provided for detecting the document sizes of A4 and A3. The area 6 is provided for detecting a document size (a change in light amount) outside the range of the AB system size.

  In the example shown in FIG. 7A, the first region is set to be shorter than the width of A5R in the main scanning direction, but may be set to the width of A5R or B5R in the main scanning direction. .

  In FIG. 7A, the numerical values in parentheses indicate the length (unit: mm) of the document in each size.

  Further, although detailed description is omitted, the image reading apparatus 10 of this embodiment can determine the paper size for 8K and 16K (paper sizes used in China), and therefore, the region 4 and the region 4 However, when determining the AB size, the area 4 or the area 5 may be omitted, or the area 4 and the area 5 may be combined into one area.

  FIG. 7B is a determination table for determining (determining) the AB system size. In the determination table, the numerical values described in the main scanning and sub-scanning columns corresponding to each size are the length (mm) of the paper in each direction. In the determination table, the symbol “◯” indicates that it is determined that there is a document in the corresponding region, and the symbol “X” indicates that it is determined that there is no document in the corresponding region. Further, in the determination table, sub-scan 1 indicates the output (on or off) of the first sub-scan sensor 230, and sub-scan 2 indicates the output of the second sub-scan sensor 232. The document size is determined based on the presence / absence of each document in region 1 to region 6 and the outputs of first sub-scanning sensor 230 and second sub-scanning sensor 232. That is, the size in the main scanning direction (size in the main scanning direction) is determined based on the presence or absence of each document in the regions 1 to 6, and according to the outputs of the first sub-scanning sensor 230 and the second sub-scanning sensor 232. A size in the sub-scanning direction (sub-scanning direction size) is determined, and a size that matches the main scanning direction size and the sub-scanning size size is determined as the document size.

  For example, according to the determination table shown in FIG. 7B, there are originals in areas 1 to 3, no originals in areas 4 to 6, and the outputs of first sub-scanning sensor 230 and second sub-scanning sensor 232 If both are on, the document size is determined to be B4.

  When it is detected that the document pressing cover 18 starts to close based on the output of the open / close sensor 164, the light source 260 is turned on, and the images of the regions 1 to 6 output from the line sensor 268 every predetermined time. Data is detected, and the amount of light (average value of luminance) for each color (RGB) in each of the regions 1 to 6 is calculated.

  For example, image data is detected (sampled) five times every 100 ms. Therefore, for each of the regions 1 to 6, the light quantity for each color for five times is acquired.

  In each of the regions 1 to 6, the maximum value and the minimum value are extracted from the amount of light for five times for each color. Then, the ratio of the minimum value to the maximum value of light quantity (light quantity ratio) is calculated. In the first embodiment, the light quantity ratio is calculated according to Equation 1 for each color.

[Formula 1]
Light intensity ratio (%) = (minimum value) / (maximum value) × 100
Therefore, the closer the light amount ratio is to 100%, the smaller the difference between the maximum value and the minimum value, that is, the smaller the change in the light amount. On the other hand, the closer the light amount ratio is to 0%, the larger the difference between the maximum value and the maximum value, that is, the greater the change in the light amount. In addition, the change (fluctuation) rate of the light quantity can be expressed by a ratio of 100-light quantity.

  Basically, in the area where the document is present (the part where it is placed), the light from the light source 260 is reflected by the document, so the document pressing cover 18 is in the open state and in the closed state. The light quantity does not change or hardly changes. On the other hand, in a region where there is no document (portion where the document is not placed), the amount of light changes in the direction in which the document pressing cover 18 is increased from the open state to the closed state.

  For this reason, in the first embodiment, it is determined whether or not there is a document for each of the areas 1 to 6 based on such an empirical rule.

  As described above, in the case where the light amount is continuously increased three times or more when detected five times, and the light amount ratio is less than a predetermined threshold (for example, 90%), the light amount Therefore, it is determined that there is no document in the area. However, in this embodiment, this determination is performed for each color in each of the areas 1 to 6, and when the conditions are satisfied for all colors, it is determined that there is no document in the corresponding area.

  In addition, that the light quantity ratio is less than the predetermined threshold value corresponds to the fluctuation rate of the light quantity being equal to or greater than the predetermined threshold value (10%).

  Further, in the first embodiment, the condition that the amount of light continuously increases three times or more is included in the condition, but this is for the purpose of reliably determining that there is no document, and this condition is omitted. May be.

  Further, the reason for satisfying the conditions for all colors as described above is that the detected light quantity varies. Therefore, not only when the conditions are satisfied for all colors, but also when any two or more colors satisfy the conditions, it may be determined that there is no document in the corresponding area. That is, it may be determined by majority vote.

  When the presence or absence of a document is determined for each of the areas 1 to 6, and the outputs (on or off) of the first sub-scanning sensor 230 and the second sub-scanning sensor 232 are detected, the determination shown in FIG. The document size is determined (detected) according to the table.

  FIG. 8 is a graph showing the ratio of the amount of light in each of regions 1 to 6 when detecting the document size of a plain paper document. FIG. 9 is a graph showing the light quantity ratio of each of the regions 1 to 6 when detecting the document size of a certain thin paper document. FIG. 10 is a graph showing the light quantity ratio of each of the regions 1 to 6 when detecting the document size of a document in which white characters are printed on black solid (filled in black).

  As described above, basically, the light from the light source 260 is reflected by the document in the area where the document is placed. For example, in the case of a document on which normal characters or / and figures (photos) are printed on plain paper, as shown in FIG. 8, the light quantity ratio is 90% in the areas 1 to 3 where the document is present. Is over. Therefore, as described above, the predetermined first threshold (initial value) is set to 90%.

  However, as shown in FIG. 9, in the case of thin paper, even in the region 1 where the document is present, a part of the light from the light source 260 is transmitted, and the amount of light continuously increases. Fluctuation will increase. Also in the case shown in FIG. 10, a part of the light from the light source 260 is reflected in the white portion, and the increase and decrease in the amount of light varies and the variation in the amount of light becomes large. That is, as shown in FIG. 10, in the area 2 where the document is present, the light amount ratio is 90% or less.

  Therefore, in this first embodiment, when the light quantity ratio of all the regions 1 to 6 is equal to or less than the first threshold value of the initial value, for example, white characters are printed on a thin paper document or a black solid. The first threshold value is changed in order to determine the document size of a document of a paper type other than plain paper or a document having a special printing method, such as a document.

  Specifically, the maximum value and the minimum value of the light quantity ratio are extracted for each color, the first threshold value for each color is calculated from the extracted maximum value and minimum value of the light quantity ratio according to Equation 2, and the changed first threshold value is obtained. Is used to determine whether or not there is a document in each of the areas 1 to 6.

  Accordingly, it is possible to correctly determine the presence or absence of a document for each of the areas 1 to 6. However, in Formula 2, [clr] indicates a color, and [blk1] to [blk6] indicate regions 1 to 6.

[Formula 2]
First threshold value [clr] = Max (light quantity ratio [blk1] [clr], light quantity ratio [blk2] [clr], light quantity ratio [blk3] [clr], light quantity ratio [blk4] [clr], light quantity ratio [blk5] [clr], light intensity ratio [blk6] [clr]) x 0.7 + Min (light intensity ratio [blk1] [clr], light intensity ratio [blk2] [clr], light intensity ratio [blk3] [clr], light intensity ratio [blk4] [clr], light intensity ratio [blk5] [clr], light intensity ratio [blk6] [clr]) × 0.3
The coefficients 0.7 and 0.3 are examples, and may be changed depending on the light source 260 to be used, for example.

  However, when the light quantity ratio of all the regions 1 to 6 is equal to or less than the second threshold value (for example, 20 (%)) smaller than the first threshold value, the document is not placed, and thus the document is placed. It tells you what to do. That is, the presence / absence of a document is determined. If there is no document, the document size is not determined.

  FIG. 11 is an illustrative view showing one example of a memory map 300 of the RAM 156 shown in FIG. As shown in FIG. 11, the RAM 156 includes a program storage area 302 and a data storage area 304. The program storage area 302 stores a control program for controlling the multifunction peripheral 100. The control program includes an operation detection program 302a, an image reading program 302b, an image formation program 302c, an open / close detection program 302d, a size detection program 302e, and the like. A threshold calculation program 302f and the like are included.

  The operation detection program 302a is a program for detecting an operation input from the operation unit 162 operated by the user. For example, the operation input includes operation data input in response to operation of various operation buttons (hardware buttons) such as a copy button and touch coordinate data input in response to operation (touch) of the touch panel. It is.

  The image reading program 302b controls the image reading unit 26 to read a document placed on a document table or a document fed from the ADF 24, and performs various image processing such as shading correction on the read image data. A program for generating image data based on an image on the surface of a document. The image forming program 302c is a program for controlling the operation of the image forming unit 30 and printing an image corresponding to the image data on recording paper (paper).

  The open / close detection program 302 d is a program for detecting the open / closed state of the document pressing cover 18. Specifically, as described above, the output of the open / close sensor 164 is detected, and it is determined (detected) whether the document pressing cover 18 is in an open state, starts to close, or is in a closed state.

  The size detection program 302e is a program for detecting the document size of the document placed on the document placement table 14a. The threshold calculation program 302f is a program for extracting the maximum value and the minimum value of the light amount ratio for each color and calculating the first threshold value for each color.

  Although illustration is omitted, the program storage area 302 also stores other programs for executing the functions of the multifunction peripheral 100.

  In the data storage area 304, an operation data buffer 304a and an image data buffer 304b are provided. The data storage area 304 stores first threshold data 304c, second threshold data 304d, sub-scan data 304e, light quantity data 304f, light quantity ratio data 304g, and size data 304h.

  The operation data buffer 304a is a buffer for temporarily storing an operation input from the operation unit 162. The image data buffer 304b is a buffer for temporarily storing image data read by the image reading unit 26, image data transmitted from an external computer, and the like.

  The first threshold value data 304c is numerical data regarding the first threshold value for determining whether or not there is a document in the areas 1 to 6. However, the first threshold value is provided for each color, and when the main power supply of the multi-function peripheral 100 is turned on, the first threshold value is set to an initial value (for example, 90% for each color), and is then regenerated according to the threshold value calculation program 302f. Updated when calculated.

  The second threshold value data 304d is numerical data on the second threshold value for determining that there are no documents in the areas 1 to 6. However, the second threshold value is the same for all colors and is a fixed value.

  The sub-scan data 304e is data indicating detection results (on or off) in which the outputs of the first sub-scan sensor 230 and the second sub-scan sensor 232 are detected.

  The light amount data 304f is numerical data regarding the number of times of scanning and the light amount of each color detected for the regions 1 to 6. The light amount ratio data 304g is numerical data regarding the light amount ratio calculated for each color for the regions 1 to 6. The size data 304h is data indicating information on the detected (determined) document size.

  Although not shown, the data storage area 304 stores other data necessary for execution of the control program, and is provided with a timer (counter) and a flag required for execution of the control program.

  12 and 13 are flowcharts showing an example of the size determination process of the CPU 150 shown in FIG. When the main power supply of the multifunction peripheral 100 is turned on or returned from the standby state (power saving mode), as shown in FIG. 12, the CPU 150 starts the size determination process, and in step S1, the document pressing cover 18 is moved. Determine if it is open. Here, the CPU 150 detects the output of the open / close sensor 164 and determines whether the light output from the light emitting unit 1640 of the optical sensor 164b is received by the light receiving unit 1642 without being blocked by the actuator 164a.

  If “NO” in the step S1, that is, if the document pressing cover 18 is in a closed state, the process returns to the step S1. On the other hand, if “YES” in the step S1, that is, if the document pressing cover 18 is in an open state, a document size detection region and a threshold value are set in a step S3. In the first embodiment, areas 1 to 6 are set, and a threshold corresponding to the threshold data is set.

  In the next step S5, it is determined whether or not the document pressing cover 18 has begun to close. Here, the CPU 150 detects the output of the open / close sensor 164 and determines whether or not the light reception amount in the open state starts to decrease.

  If “NO” in the step S5, that is, if the document pressing cover 18 is opened, the process returns to the same step S5. On the other hand, if “YES” in the step S5, that is, if the document pressing cover 18 starts to be closed, the detection results (on or off) of the first sub-scanning sensor 230 and the second sub-scanning sensor 232 in a step S7. To get. Here, the CPU 150 stores the sub-scan data 304e indicating the detection result in the data storage area 304 of the RAM 156.

  In the next step S9, the light source 260 is turned on, and in step S11, an initial value is set in the variable M (M = 1). The variable M is provided for counting the number of times the scan is executed.

  Subsequently, in step S13, the output of the line sensor 268 is detected, and in step S15, the amount of light in each M-th region (region 1 to region 6 in the first embodiment) is stored for each color. That is, the light quantity data 304 f for the Mth time is stored (added) in the RAM 156.

  In the next step S17, the variable M is incremented by 1 (M = M + 1). In step S19, it is determined whether the variable M has exceeded a predetermined number of times (5 times in the first embodiment). If “NO” in the step S19, that is, if the variable M is equal to or less than the predetermined number, the process returns to the step S13. On the other hand, if “YES” in the step S19, that is, if the variable M exceeds the predetermined number, the process proceeds to a step S21 shown in FIG.

  In the first embodiment, the scan time in steps S13 to S19 is set to a predetermined time (500 msec).

  As shown in FIG. 13, in step S <b> 21, the light amount ratio is calculated for each color according to Equation 1 in each of the regions 1 to 6. Here, light amount ratio data 304 g corresponding to the light amount ratio for each color calculated for each region is stored in the data storage region 304 of the RAM 156.

  In the next step S23, it is determined whether or not the light quantity ratios of all the regions 1 to 6 are equal to or less than the first threshold value. If “NO” in the step S23, that is, if the light amount ratio exceeds the first threshold corresponding to the first threshold data 304c in any one of the areas 1 to 6, the process proceeds to the step S33. .

  On the other hand, if “YES” in the step S23, that is, if the light amount ratios of all the regions 1 to 6 are not more than the first threshold value, the light amount ratios of all the regions 1 to 6 are set to the second light amount in the step S25. It is determined whether or not it is equal to or smaller than a second threshold corresponding to the threshold data 304d.

  If “YES” in the step S25, that is, if the light quantity ratios of all the regions 1 to 6 are equal to or less than the second threshold value, it is determined that the document is not placed on the document placing table 14a, and in a step S27. Then, the fact that the document should be placed is notified, and the size determination process is terminated. For example, in step S27, a message indicating that the document should be placed is displayed, a sound indicating that is output, or both are executed.

  On the other hand, if “NO” in the step S25, that is, if the light amount ratio exceeds the second threshold value in any one of the regions 1 to 6, all the regions 1 to 1 are determined in a step S29. In step 6, the maximum value and the minimum value of the light amount ratio are extracted for each color. In step S31, the first threshold value is calculated for each color in accordance with Equation 2, and the first threshold value data 304c corresponding to the calculated first threshold value is stored (changed) in the data storage area 304 of the RAM 156.

  Subsequently, in step S33, it is determined whether or not there is a document for each of the areas 1 to 6. As described above, for each color, it is determined whether the amount of light has increased continuously three times or more, and for each color, it is determined whether the light amount ratio is equal to or less than the first threshold value. It is determined that there is no document for an area that satisfies these conditions. On the other hand, it is determined that there is a document for an area that does not satisfy these conditions.

  In the next step S35, the document size is determined and the size determination process is terminated. In step S35, the determination shown in FIG. 7B is performed based on the outputs of the first sub-scanning sensor 230 and the second sub-scanning sensor 232 indicated by the sub-scanning data 304e and the presence / absence of documents in each of the areas 1 to 6. The corresponding document size is determined according to the table. When the document size is determined, the size data 304h regarding the determined document size information is stored in the data storage area 304 and used in the subsequent printing process or the like.

  According to the first embodiment, when the document pressing cover 18 starts to close, the light source 260 is turned on to change the light amount in each of the regions 1 to 6 set in the main scanning direction and the light amount at a predetermined sampling number. Based on the result of detecting the presence / absence of a document in each of the regions 1 to 6 based on the light amount ratio represented by the ratio of the minimum value to the maximum value, and the result of detecting the outputs of the two sub-scanning sensors 230 and 232 Therefore, the document size can be detected without closing the document pressing cover 18. Therefore, the document size can be detected even for a relatively thick document such as a book.

  Further, according to the first embodiment, since the number of light amounts (image data) in the areas 1 to 6 is small and the sampling time interval is short, even when the user closes the document pressing cover 18 quickly. The document size can be detected.

[Second Embodiment]
The image reading apparatus 10 of the second embodiment is the same as that of the first embodiment except for determining an inch-size document size, and therefore, a duplicate description is omitted or briefly described.

  FIG. 14A is an illustrative view showing divided areas set for all reading areas in the main scanning direction when an inch-size document size is determined. As shown in FIG. 14B, when determining an inch-based document size, four regions 1, 2, 3, and 4 are set in the main scanning direction. Similar to the case of determining the AB-size original size, a plurality of areas (divided areas) for determining the inch-size original size are set as all the scan areas in the main scanning direction.

  In FIG. 14A, the numerical values in parentheses indicate the length (unit: mm) of the document at each size.

  FIG. 14B is an illustrative view showing one example of a determination table for determining (determining) an inch-based document size. Also in this determination table, as in the first embodiment, the symbol ◯ indicates that it is determined that there is a document in the corresponding region, and the symbol X indicates that there is no document in the corresponding region. It shows that. In the determination table, sub-scan 1 indicates the output (on or off) of the first sub-scan sensor 230, and sub-scan 2 indicates the output of the second sub-scan sensor 232.

  Also in the second embodiment, the document size determination process is executed according to the flowcharts shown in FIGS. 12 and 13 except that the divided areas set in all the scanning areas in the main scanning direction and the determination table are different.

  According to the second embodiment, as in the first embodiment, the document size can be detected without closing the document pressing cover 18. Even when the user closes the document pressing cover 18 quickly, the document size can be detected.

[Third embodiment]
The image reading apparatus 10 according to the third embodiment executes a detection process without a document, and only executes a threshold calculation process and a document size determination process when no document is detected. Since it is the same as that of the first embodiment, a duplicate description is omitted.

  In the third embodiment, as described in the first embodiment, when the document pressing cover 18 starts to be closed, scanning (sampling) of image data is started. When scanning is performed a predetermined number of times, first, the light amount ratio and the light amount fluctuation rate for each of the regions 1 to 6 for some colors (color G in the third embodiment) are calculated. Then, it is determined that the document is not placed on the document placing table 14a using the light quantity ratio and the light quantity fluctuation rate for the partial color G.

  If it is not determined that the document is not placed on the document placement table 14a, the light quantity ratio is calculated for each of the regions 1 to 6 for the other colors (color R and color B) according to Equation 1, As in the first embodiment, the document size is determined.

  On the other hand, if it is determined that the document is not placed on the document placement table 14a, the light amount ratio calculation for other colors (S21b), the first threshold value calculation (S29, S31), and the document size The determination (S33, S35) is not performed. In this case, it is notified that the document is not placed on the document placing table 14a.

  Here, in the third embodiment, a method for determining that a document is not placed on the document placing table 14a will be described.

  As described above, in the document placing table 14a, the document is placed so that the upper left vertex when the document placing table 14a is viewed from above is the reference position, and the corner of the document is aligned with the reference position. For this reason, in the state where the document is placed on the document placing table 14a, the light quantity ratio is usually large in the region 1 and the region 2. On the other hand, in the region 6, the light quantity ratio is small. Further, the document pressing cover 18 is connected by a hinge or the like on the back side of the document placing table 14a, and is opened only about 60 degrees with respect to the document placing table 14a even in the open state. The back side is covered with a document pressing cover 18. Therefore, when the document is not placed on the document placing table 14a, the light amount ratio of the region 1 and the region 2 may be smaller than the light amount ratio of the region 6.

  Therefore, one condition for determining that the document is not placed on the document placement table 14 a is that the light amount ratio in the region 1 and the region 2 is smaller than the light amount ratio in the region 6.

  Further, when the document is not placed on the document placing table 14a, the light amount ratio becomes small, and another condition is that the light amount ratios of the region 1 and the region 2 are equal to or less than the third threshold value. For example, the third threshold value is set to 20% by performing an experiment or the like.

  When the condition 1 or the condition 2 is satisfied, it is determined that the document is not placed on the document placing table 14a. When the first condition and the second condition are not satisfied, it is determined that the document is placed on the document placing table 14a, and the document size is determined by the method described in the first embodiment.

  Therefore, in the third embodiment, numerical data corresponding to the third threshold value is further stored in the data storage area 304.

  Hereinafter, the document size determination process of the CPU 150 in the third embodiment will be described. However, since only part of the determination process shown in FIGS. 12 and 13 is different, different contents will be described.

  Of the determination processes shown in FIGS. 12 and 13, steps S1 to S19 and S29 to S35 are the same. Therefore, if “YES” in the step S19, as shown in FIG. 15, the light quantity ratio of the color G is calculated according to the equation 1 in each of the regions 1 to 6 in a step S21a.

  In the next step S51, it is determined whether or not the light amount ratio of the region 1 and the region 2 is smaller than the light amount ratio of the region 6. If “YES” in the step S51, that is, if the light amount ratio of the region 1 and the region 2 is smaller than the light amount ratio of the region 6, it is determined that the document is not placed on the document placing table 14a. Proceed to step S27.

  On the other hand, if “NO” in the step S51, that is, if the light amount ratio of the region 1 and the region 2 is equal to or larger than the light amount ratio of the region 6, the light amount ratio of the region 1 and the region 2 is equal to or less than the third threshold value in a step S53. It is determined whether or not.

  If “YES” in the step S53, that is, if the light quantity ratio of the region 1 and the region 2 is equal to or smaller than the third threshold value, it is determined that the document is not placed on the document placing table 14a, and the step S27. Proceed to

  On the other hand, if “NO” in the step S53, that is, if the light quantity ratio of the region 1 and the region 2 exceeds the third threshold value, it is determined that the document is placed on the document placing table 14a. In step S21b, the light quantity ratio of the other colors (color R and color B) is calculated for each of the regions 1 to 6 according to Equation 1, and the process proceeds to step S23.

  In step S23, for each color, it is determined whether or not the light amount ratio of each of the regions 1 to 6 is equal to or less than the first threshold value. If “YES” in the step S23, the process proceeds to a step S29. On the other hand, if “NO” in the step S23, the process proceeds to a step S33.

  According to the third embodiment, before the threshold value is calculated and the document size is determined, it is determined whether or not the document is placed on the document placement table 14a. Therefore, it is not necessary to calculate the threshold and determine the document size. That is, useless processing can be reduced.

  The modification of the third embodiment can also be adopted in the second embodiment.

  In the third embodiment, when it is determined whether or not the condition 1 or 2 is satisfied, only the light amount ratio (light amount variation rate) of the color G is used, but the color R and / or the color B is used. A light quantity ratio may also be used.

  Furthermore, the screens and specific numerical values given in the above-described embodiments are examples, and can be appropriately changed according to the actual product. Moreover, when the same effect is acquired, the order of each step shown to the flowchart may be changed suitably. Further, in the comparison process using the threshold value, the magnitude relationship may be determined without including the threshold value.

DESCRIPTION OF SYMBOLS 10 ... Image reading device 12 ... MFP main body 14a ... Original plate glass 14b ... SPF glass 18 ... Original press cover 28 ... Control part 30 ... Image forming part 32 ... Exposure unit 34 ... Developing roller 36 ... Photoconductor drum 38 ... Cleaner unit DESCRIPTION OF SYMBOLS 40 ... Charging device 42 ... Intermediate transfer unit 44 ... Transfer roller 46 ... Fixing roller 100 ... Multifunction machine 150 ... CPU
154 ROM
156 ... RAM
158 ... HDD
DESCRIPTION OF SYMBOLS 160 ... Image signal processing circuit 164 ... Opening / closing sensor 206 ... Scanner motor 230 ... Size detection sensor 260 ... Light source 268 ... Line sensor 270 ... Scanning unit

Claims (10)

An image reading apparatus including a document pressing cover that covers a document placed on a transparent plate, and a reading unit including at least an image reading element,
A first size detection unit for detecting a first size of the document in the sub-scanning direction of the reading unit;
A cover detection unit for detecting that at least the document pressing cover is moving in the closing direction;
A light amount detection unit for detecting the light amount of each of the plurality of divided regions in the main scanning direction at predetermined time intervals in response to the detection of the document pressing cover moving in the closing direction by the cover detection unit;
A ratio calculating unit that calculates a ratio of the amount of light based on the maximum value and the minimum value of each of the divided regions detected by the light amount detection unit;
A second size detecting unit that detects a second size of the document in the main scanning direction of the reading unit based on a calculation result of the ratio calculating unit;
An image reading apparatus comprising: a document size determination unit that determines a document size based on a detection result of the first size detection unit and a detection result of the second size detection unit. A presence / absence determining unit that determines presence / absence of a document in each divided region based on whether the ratio calculated by the ratio calculating unit exceeds a predetermined threshold;
2. The image reading apparatus according to claim 1, wherein the second size detection unit detects the second size based on the divided area determined by the presence / absence determination unit that a document is present.   The image reading apparatus according to claim 2, further comprising a recalculation unit that recalculates the threshold value from a maximum value and a minimum value of a light amount ratio in all the divided regions.   4. The apparatus according to claim 1, further comprising: a region presence / absence determining unit configured to determine that the document is not placed in the divided region when the light amount of the divided region continuously increases a plurality of times. An image reading apparatus according to claim 1. A non-placement determining unit that determines whether the document is not placed on the transparent plate according to whether the ratio calculated by the ratio calculating unit satisfies a predetermined condition;
5. The processing according to claim 1, wherein when the non-placement determination unit does not determine that the document is not placed on the transparent plate, the second size detection unit and the document size determination unit execute processing. The image reading apparatus according to any one of the above.   6. The image reading apparatus according to claim 1, wherein the divided area is changed between when the document size is determined as an AB size and when the document size is determined as an inch size. An image reading apparatus including a document pressing cover that covers a document placed on a transparent plate, and a reading unit including at least an image reading element,
A cover detection unit for detecting that at least the document pressing cover is moving in the closing direction;
A light amount detection unit for detecting the light amount of each of the plurality of divided regions in the main scanning direction at predetermined time intervals in response to the detection of the document pressing cover moving in the closing direction by the cover detection unit;
A ratio calculating unit that calculates a ratio of the amount of light based on the maximum value and the minimum value of each of the divided regions detected by the light amount detection unit;
An image reading apparatus comprising: a placement determination unit that determines whether the document is placed on the transparent plate based on a calculation result of the ratio calculation unit.   An image forming apparatus comprising the image reading apparatus according to claim 1. A control program that is executed by an image reading apparatus that includes a document pressing cover that covers a document placed on a transparent plate, and a reading unit that includes at least an image reading element,
In the processor of the image reading device,
A first size detecting step of detecting a first size of the document in the sub-scanning direction of the reading unit;
A cover detecting step for detecting that at least the document pressing cover is moving in the closing direction;
A light amount detecting step for detecting the light amount of each of the plurality of divided regions in the main scanning direction at predetermined time intervals in response to detecting that the document pressing cover is moving in the closing direction in the cover detecting step;
A ratio calculating step for calculating a ratio of the light quantity based on the maximum value and the minimum value of each light quantity of the divided areas detected in the light quantity detection step;
A second size detecting step of detecting a second size of the document in the main scanning direction of the reading unit based on a calculation result of the ratio calculating step;
A control program that causes a document size determination unit to determine a document size based on the detection result of the first size detection step and the detection result of the second size detection step. A method for controlling an image reading apparatus, comprising: a document pressing cover that covers a document placed on a transparent plate; and a reading unit including at least an image reading element,
(A) detecting a first size of the document in the sub-scanning direction of the reading unit;
(B) detecting that at least the document pressing cover is moving in the closing direction;
(C) detecting the light amount of each of the plurality of divided areas in the main scanning direction at predetermined time intervals in response to detecting that the document pressing cover is moving in the closing direction in the cover detection unit;
(D) calculating a light amount ratio based on a maximum value and a minimum value of each light amount of the divided areas detected in the light amount detection step;
(E) detecting a second size of the document in the main scanning direction of the reading unit based on a calculation result of the ratio calculating step;
(F) A control method including a step of determining a document size based on a detection result of the first size detection step and a detection result of the second size detection step.

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