JP2018137793A - Image reading apparatus, computer program, and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a state of a document cover even in the absence of a posture sensor.SOLUTION: An image reading apparatus comprises a document platen, a document cover, a light source, a reading part, a reading mechanism, and a controller. The controller executes a change process to change a reading position to a detection position, an opening determination process to determine that the document cover is open when digital data of an area in which a document is not placed is not smaller than a cover determination value, and a closing determination process to determine that the document cover is closed when the digital data of the area in which the document is not placed is smaller than the cover determination value.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an image reading apparatus.

When reading a document placed on the document table, it is necessary to determine whether or not the document cover is in a fully closed position.
The image reading apparatus described in Patent Document 1 detects the orientation of the document cover with an orientation sensor, turns on the light source, and executes document reading.

Japanese Patent Laid-Open No. 2005-20049

  However, since the state of the document cover is detected using the attitude sensor, the entire apparatus becomes large, and further, an apparatus configuration for detecting the output of the sensor is required, which complicates the apparatus configuration. It was.

  Accordingly, the present invention has been made in view of the above-described circumstances, and an object of the present invention is to detect the state of a document cover even in a state where there is no attitude sensor.

In order to achieve the above object, according to the first aspect of the present invention, there is provided an image reading apparatus in which a reference point on which one vertex of a document to be read is to be placed is provided and the document is not supported a document table which has a non-mounting region, and a document cover that opens and closes the open state to open the upper surface of the closed state covering the upper surface of the document table the document table, a light source for emitting light, A reading unit that performs reading to acquire the amount of light received in units of lines along the main scanning direction as digital data; a reading mechanism that changes a reading position to execute the reading in a sub-scanning direction orthogonal to the main scanning direction; comprising a controller, wherein the controller includes a change process in which the reading unit is changed by the reading mechanism of the reading position to the detection position for detecting the disturbance light in the original non-placing area, the reading position before In the state where the detection position is changed, no light is emitted from the light source, and the document cover is determined to be open when the digital data in the document non-loading area in the main scanning direction is equal to or greater than the cover determination value. After the determination process and the open determination process, the document cover is determined to be in the open state, and the reading position is changed to the detection position, and the light source is not irradiated with light, and the light source is not irradiated with light. A closing determination process for determining that the document cover is in a closed state when the digital data of the document non-loading area is equal to or less than the cover determination value .

According to a specific aspect of the present invention, the document table includes, as a blank area, an area from a reference line parallel to the sub-scanning direction passing through the reference point to a position separated by a predetermined distance in the main scanning direction. The controller includes a lighting process for controlling the light source by using two lines, which are a combination of a lighting line for irradiating light from the light source and a lighting line for turning off the light source, and the document cover is opened in the opening determination process. After being determined to be in a state, the document is supported in the margin area when the difference between the digital data of the lighting line in the margin area and the digital data of the extinguished line in the margin area is larger than the document determination value. and a document determination process of determining that, by the execution, the closed determination process, after it is determined that the document in the margin area in the original determination process is supported , It is executed.

According to a specific aspect of the present invention, there is provided a method executed by an image reading apparatus, wherein the image reading apparatus is provided with a reference point on which one vertex of a document to be read is to be arranged, and the document a document mounting table but has an original non-placing area that is not placed, a document cover that opens and closes to the open state to open the upper surface of the original placing top the document table in the closed state of covering the base, the light A light source that irradiates; a reading unit that executes reading to acquire the amount of light received in units of lines along the main scanning direction as digital data; and a reading mechanism that changes a reading position to execute the reading in the sub-scanning direction. The method includes a changing step of changing the reading position by the reading mechanism to a detection position where the reading unit detects disturbance light in the document non-loading region, and a state in which the reading position is changed to the detection position In An opening determination step of determining that the document cover is in an open state when the digital data of the document non-loading area in the main scanning direction is equal to or greater than a cover determination value without irradiating light from the light source; After the determination that the document cover is in the open state in the determination processing, light is not emitted from the light source in a state where the reading position is changed to the detection position, and the document non-loading area in the main scanning direction is not irradiated. A closing determination step of determining that the document cover is in a closed state when the digital data is equal to or less than the cover determination value .

In the first aspect of the invention, the changing process changes the reading position to the detection position by the reading mechanism. In the open determination process, light is not emitted from the light source, and it is determined that the document cover is in the open state when the digital data of the document non-loading area in the main scanning direction is equal to or greater than the cover determination value. In the closing determination process, it is determined that the document cover is in a closed state when light is not emitted from the light source and the digital data in the document non-loading area in the main scanning direction is equal to or less than the cover determination value. Accordingly, since the state of the document cover can be detected according to the digital data in the document non-placement area, the state of the document cover can be detected even when there is no attitude sensor for detecting the document cover.

According to a specific aspect of the present invention, the document determination process is performed when the difference between the digital data of the lighting line in the blank area and the digital data of the blank line in the blank area is within the document determination value. Is determined to be supported. Therefore, since it can be determined that the original is supported by the digital data of the lighting line in the margin area and the digital data of the off-line in the margin area, the original is supported even when there is no original sensor for detecting the original. Can be judged.

According to a specific aspect of the present invention, the changing step causes the reading mechanism to change the reading position to the detection position. In the open determination step, it is determined that the document cover is in the open state when the digital data in the document non-placement area in the main scanning direction is equal to or greater than the cover determination value without irradiating light from the light source. In the closing determination step, it is determined that the document cover is in the closed state when light from the light source is not emitted and the digital data in the document non-placement area in the main scanning direction is equal to or less than the cover determination value. Accordingly, since the state of the document cover can be detected according to the digital data in the document non-placement area, the state of the document cover can be detected even when there is no attitude sensor for detecting the document cover.

(A) It is drawing which shows the internal structure of the image reading apparatus 1 which concerns on embodiment of this invention. (B) It is a top view of transparent board TP. 2 is a block diagram illustrating a control configuration of the image reading apparatus 1. FIG. It is a flowchart which shows the power-on process M1. 10 is a flowchart showing document size determination processing (T9). It is a flowchart which shows re-original size determination processing (TA12). It is a flowchart which shows a reading process (T11). 6 is a diagram illustrating a relationship between a main scanning position and digital data in each document cover state. 6 is a diagram illustrating a relationship between a main scanning position and a gradation value in each document cover state.

(Configuration of Image Reading Device SM)
FIG. 1A shows a front view of the image reading device SM. The image reading device SM includes a document placement table DT and a cover CV. The document placing table DT includes a main body MB and a transparent plate TP. The main body MB is a housing for accommodating various members (for example, the transparent plate TP, the reading unit RU, etc.). The transparent plate TP is accommodated in the main body MB and is fixed to the main body MB. A document to be read is placed on the transparent plate TP. The document cover CV is disposed on the upper part of the main body MB and can be opened and closed with respect to the main body MB. As for the opening and closing direction, a rotation shaft is provided on the back side of the main body MB (back side perpendicular to the paper surface of FIG. 1A), and the main body MB is opened and closed from the front side. That is, the cover CV is provided with a rotation shaft on the margin area side, which will be described later, and is opened and closed from the document non-placement area side. The back surface of the document cover CV, that is, the surface on the transparent plate TP side of the document cover CV is white.

  The image reading device SM further includes a reading unit RU accommodated in the main body MB below the transparent plate TP. The reading unit RU is movable along the sub-scanning direction (that is, the left-right direction in FIG. 1A) with respect to the main body MB. The reading unit RU reads a document placed on the transparent plate TP. The reading unit RU is configured by a CIS (abbreviation of Contact Image Sensor), and specifically includes a light source LS, a rod lens RL, and an image sensor IS. The light source LS emits light toward the transparent plate TP. The rod lens RL receives reflected light of light emitted from the light source LS. The imaging element IS receives light that has passed through the rod lens RL. More specifically, the image sensor IS is composed of a plurality of optical elements arranged along the main scanning direction (that is, the direction perpendicular to the paper surface of FIG. 1A). That is, the image sensor IS is a line sensor that performs reading in units of lines along the main scanning direction in which a plurality of optical elements are arranged. Hereinafter, a position where the image sensor IS is present in the sub-scanning direction is referred to as a “reading position”.

  FIG. 1B shows a plan view of the transparent plate TP. The transparent plate TP has a rectangular shape constituted by long sides extending along the sub-scanning direction and short sides extending along the main scanning direction. One apex of the document DC to be read is arranged at one end in the main scanning direction (that is, the left side in FIG. 1B) of the surface exposed to the document cover CV side of the transparent plate TP. A power reference point OP is provided. A document DC is placed on the transparent plate TP. A state in which the A4 size original DC is placed in a horizontal state is called an A4 horizontal original DC, and is illustrated by a broken line. In the “horizontal state”, the long side of the original DC is along the long side of the exposed surface of the transparent plate TP, and the short side of the original DC is along the short side of the exposed surface of the transparent plate TP. This is a state of being placed on the transparent plate TP. Of the short sides of the document DC, a short side including the reference point OP is set as a reference side, and a short side facing the reference side is set as an opposing side. Hereinafter, in the sub-scanning direction, the position of the reference side is referred to as “reference position BP”, and the position of the opposite side of the A4 landscape original DC is referred to as “A4 landscape position LP”. In the sub-scanning direction, the long side of the exposed surface of the transparent plate TP including the reference point OP is referred to as a “reference line”. Note that the transparent plate TP has a size that allows the A3 size (hereinafter referred to as A3 landscape) document DC in a horizontally placed state to be placed with the maximum document size. The A3 landscape original DC is illustrated by a one-dot chain line.

  In the main scanning direction, a blank area (upward slanted line area in FIG. 1B) within 3 mm from the reference line to the document placement side (that is, the lower side in FIG. 1B) is transparent without including the reference point OP. A document non-mounting area (from the long side of the exposed surface of the plate TP (in other words, the side facing the reference line) to the area where the A3 horizontal size original, which is the maximum size that can be placed, is placed ( A diagonally downward slanting area in FIG.

  The image reading device SM further includes a reference member BM fixed to the upper surface of the transparent plate TP. The reference member BM is provided at one end of the transparent plate TP in the main scanning direction (that is, the left side in FIG. 1B). The reference member BM is a white member that extends along the main scanning direction, and is used to acquire white data to be described later. Hereinafter, the position where the reference member BM is provided in the sub-scanning direction is referred to as “home position HP”.

(Control configuration of image reading device SM)
FIG. 2 shows a control configuration of the image reading device SM. The image reading device SM further includes an operation mechanism OM, a display mechanism DM, a reading mechanism RM, and a control unit CU. The operation mechanism OM is composed of a plurality of keys. The user can input various instructions to the image reading device SM by operating the operation mechanism OM. The display mechanism DM is a display for displaying various information. The control unit CU includes a controller CR and a memory ME. The controller CR is a processor that executes various processes (for example, processes shown in FIGS. 3 to 6 described later) according to the program PGM stored in the memory ME.

  The reading mechanism RM includes a reading unit RU, a moving mechanism MM, an A / D conversion unit AD, and a correction unit SC. The moving mechanism MM moves the reading unit RU along the sub-scanning direction. The A / D conversion unit AD converts analog data output from the reading unit RU into digital data. The correction unit SC performs shading correction of the digital data converted by the A / D conversion unit to a gradation value using white data and black data described later. Here, the digital data converted in the A / D conversion unit AD is configured to be output to the memory ME, and is also configured to be output to the correction unit SC. The digital data output to the memory ME is stored in the memory ME. The gradation value converted in the correction unit SC is output to the memory ME and stored in the memory ME.

(Main process M1 power-on process)
Next, the contents of the power-on process executed by the controller CR will be described with reference to FIG. The controller CR starts the power-on process (M1) in FIG. 3 when the image reading device SM is powered on.

  When the power-on process (M1) is started, the controller CR controls the moving mechanism MM to move the reading unit RU so that the reading position is changed from the position when the image reading device SM is turned off to the home position HP. Change (T1). Thereby, in the sub-scanning direction, the reading position of the reading unit RU, that is, the position of the imaging element IS coincides with the position of the reference member BM.

  The controller CR adjusts the light amount LE during reading (T2). Specifically, the controller CR emits light from the light source LS toward the reference member BM, and the analog data when the reflected light is read reaches the maximum value of the A / D conversion unit AD. The light quantity LE of LS is adjusted. Here, the light amount LE is determined by the lighting time and current value in one line of the light source LS.

  The controller CR acquires the black data BK (T3). Specifically, the controller CR turns off the light source LS, causes the reading unit RU to read one line, and stores the read digital data for one line in the memory ME as black data BK. The digital data at this time is a dark output.

  The controller CR acquires white data WT (T4). Specifically, the controller CR turns on the light source LS with the light amount LE, causes the reading unit RU to read one line, and stores the read digital data for one line in the memory ME as white data WT.

  The controller CR calculates a cover determination value THco (T5). Specifically, the controller CR obtains the black data BK from the memory ME, and calculates the black data maximum value BKmax by extracting the maximum value of the data in the document non-placement area from the black data BK. Further, a value calculated by multiplying the black data maximum value BKmax by 1.1 is set as a cover determination value THco.

  The controller CR controls the moving mechanism MM to move the reading unit RU and changes the reading position from the home position HP to the A4 lateral position LP (T6). Thereby, in the sub-scanning direction, the reading position of the reading unit RU becomes a position corresponding to the opposite side of the A4 side original. Here, the “position corresponding to the opposite side” means a position slightly shifted to the inside of the document from the opposite side (for example, 3 mm inside the opposite side).

  The controller CR acquires the set value from the memory ME (T7). Here, the set values are a reading range, a reading resolution, and the like. The reading range in the main scanning direction is set to the maximum reading range in which the document non-placement area can be read, and the reading resolution is set to 300 dpi.

  The controller CR determines whether or not ambient light has been detected (T8). Specifically, the controller CR determines whether or not all digital data of specific pixels in the document non-placement area is equal to or greater than the cover determination value THco. If it is equal to or greater than the cover determination value THco, it is determined that ambient light has been detected (Yes in T8), and the process proceeds to document size determination processing (T9). If it is smaller than the cover determination value THco, it is determined that ambient light has not been detected (No in T8), and the process proceeds to processing (T10) for determining whether or not the reading start button has been pressed. This process (T9) is repeatedly executed while the reading button is not pressed (No in T10), and always detects the incidence of disturbance light. Here, the specific pixels in the document non-placement area may be all the pixels existing in the document non-placement area, or may be a plurality of pixels close to the end of the transparent plate TP away from the reference point OP in the main scanning direction.

  The controller CR determines the document size (T9). Although details will be described later, the controller CR determines the presence or absence of a document using the digital data of the margin area. Thereafter, the controller CR generates an acquisition timing for acquiring a gradation value SZA for determining the document size using the digital data of the document non-loading area, and the gradation value SZA acquired at the generated acquisition timing. Use to confirm the document size.

  The controller CR determines whether or not the reading start button has been pressed (T10). When the reading start button is pressed (Yes in T10), the process proceeds to the reading process (T11). If the reading start button has not been pressed (No in T10), the process proceeds to a determination process (T8) as to whether ambient light has been detected.

  The controller CR causes the reading unit RU to perform reading (T11). Although details will be described later, the controller CR sets a reading range corresponding to the document size determined in the document size determination process (T9), controls the moving mechanism MM, and causes the reading unit RU to perform reading.

(Original Size Determination Process T9)
The document size determination process (T9) will be described with reference to FIG. The document size determination process (T9) is executed by detecting disturbance light at T8. In other words, the document size determination process (T9) is started when the document cover CV is opened and disturbance light is incident on the reading unit RU at the A4 lateral position LP.

  The controller CR performs lighting control of the light source LS during the document size determination process (TA1). Specifically, the controller CR reads a total of two lines, ie, a line that irradiates the light source LS with the light amount LE (hereinafter referred to as a lighted line) and a line that turns off the light source LS (hereinafter referred to as a lighted line). Lighting control is performed as a reading line. Here, although the case where one line is used as the lighting line is described, the color of the light source LS may be sequentially turned on, and three lines of red, green, and blue may be used as the lighting lines.

  The controller CR determines whether or not a document is detected in the blank area (TA2). That is, the controller CR determines whether or not the difference between the digital data of the lighting line and the digital data of the extinguishing line is within the document determination value for the specific pixel in the blank area. If it is within the document discrimination value, it is determined that there is no document (No in TA2), and the process proceeds to processing (TA3) for determining whether or not a predetermined time has passed. If it is larger than the document discrimination value, it is determined that there is a document (Yes in TA2), and the process proceeds to processing (TA4) for determining whether or not a document is detected in the document non-loading area. This process (TA2) is repeatedly executed while a predetermined time elapses (No in TA3), and always detects a document. Here, since the document discrimination value is used to determine whether or not there is a document, it is necessary to set the document discrimination value larger than the fluctuation amount due to random noise superimposed on the analog data. The specific pixels in the margin area may be all the pixels existing in the margin area, or may be a plurality of pixels at the end of the transparent plate TP close to the reference point OP in the main scanning direction.

  The controller CR determines whether or not a predetermined time has elapsed (TA3). If the predetermined time has elapsed (Yes in TA3), the controller CR proceeds to processing (TA11) for determining whether or not the document cover CV is closed. If the predetermined time has not elapsed (No in TA3), The process proceeds to a process (TA2) for determining whether or not a document is detected in the margin area.

  The controller CR determines whether or not a document is detected in the document non-loading area (TA4). That is, the controller CR determines whether or not the difference between the digital data of the lighting line and the digital data of the extinguishing line is within the document discrimination value for a specific pixel in the document non-loading area. If it is within the document determination value, it is determined that there is no document (No in TA4), and the process proceeds to processing (TA5) for determining whether the document non-placement area is equal to or less than the cover determination value. If it is larger than the document discrimination value, it is determined that there is a document (Yes in TA4), and the process proceeds to processing (TA7) for determining the document size on the side of A3. When a document is detected in the document non-loading area, the document size is fixed beside A3 which is the maximum reading size.

  The controller CR determines whether or not the document determination area is equal to or less than the cover determination value (TA5). That is, the controller CR determines whether or not all the digital data of the specific pixel in the document non-placement area of the light-off line is equal to or less than the cover determination value THco. When it is equal to or less than the cover determination value THco, it is determined that the document cover CV is immediately before being closed (Yes in TA5), and the process proceeds to a line data acquisition process (TA8). If it is greater than the cover determination value THco, it is determined that the document cover CV is in an open state (No in TA5), and the process proceeds to a process (TA6) for determining whether or not a predetermined time has elapsed. This process (TA5) is repeatedly executed while the predetermined time has elapsed (No in TA6), and the state of the document cover CV is always determined. Here, “immediately before the document cover CV is closed” is the acquisition timing for acquiring the gradation value SZA for determining the document size.

  The controller CR determines whether or not a predetermined time has elapsed (TA6). That is, if the predetermined time has elapsed (Yes in TA6), the controller CR proceeds to a process of determining the document size on the side of A3 (TA7). If the predetermined time has not elapsed (No in TA6), the controller CR The process proceeds to the process (TA5) for determining whether or not the placement area is equal to or less than the cover determination value. If the document non-loading area does not fall below the cover determination value even after the predetermined time has elapsed, the cover is open and the document size is fixed to A3 side.

  The controller CR determines the document size on the side of A3 (TA7).

  The controller CR acquires the gradation value SZA for one line of the lighting line (TA8). That is, the controller CR acquires the gradation value SZA for one lighting line immediately before the document cover CV is closed.

  The controller CR calculates a threshold value SZ1 (TA9). That is, the controller CR calculates an average value of the gradation value BL1 indicating the intermediate value in the blank area and the gradation value NO1 indicating the intermediate value in the document non-loading area among the gradation values SZA acquired at TA8. The threshold value is SZ1. The “intermediate value” refers to the gradation value indicated by the pixel in the middle order when all the pixels in the blank area are arranged in order so that the gradation value increases. Here, the gradation value BL1 is an intermediate value of the blank area in the gradation value SZA, but may be an average value of all the pixels in the blank area. Similarly, the gradation value NO1 may be an average value of all pixels in the document non-placement area.

  The controller CR determines the document size (TA10). Specifically, the controller CR sets the position of the pixel closest to the document non-placement area as the document end portion among the pixels indicating the gradation value smaller than the threshold value SZ1 with respect to the gradation value SZA for one line. to decide. The distance between the reference line in the sub-scanning direction passing through the reference point OP and the document edge is determined as the document size in the main scanning direction. The document size is determined from the determined size of the document in the main scanning direction and the size of the document in the sub-scanning direction being A4 or more. However, if the determined document size in the main scanning direction is different from the standard paper size, the document size in the sub-scanning direction is determined as A3 horizontal. Since the document size is determined using the gradation value SZA at the A4 horizontal position LP, it is possible to determine a larger number of document sizes than when the detection is performed at the A3 horizontal position.

  The controller CR determines whether or not the document cover CV is closed (TA11). That is, the controller CR determines whether or not all the digital data of the specific pixel in the document non-placement area of the light-off line is equal to or less than the cover determination value THco. If it is equal to or less than the cover determination value THco, it is determined that the document cover CV is in a closed state (Yes in TA11), and the process proceeds to a re-document size determination process (TA12). If it is larger than the cover determination value THco, it is determined that the document cover CV is in an open state (No in TA11), and the process proceeds to a cover close flag OFF process (TA7).

  The controller CR changes the reading position from the A4 horizontal position LP to the reference position BP, and determines the document size (TA12). As will be described in detail later, the controller CR determines whether or not the threshold used for document size determination can be calculated without opening the document cover CV. If the document size cannot be determined without opening the document cover CV, A display for instructing the opening / closing operation of the document cover CV is performed, and the user opens / closes the document cover CV to determine the document size.

  The controller CR turns on the cover close flag (TA13). That is, the controller CR sets the cover open flag stored in the memory ME to ON.

  The controller CR turns off the cover close flag (TA14). That is, the controller CR sets the cover close flag stored in the memory ME to OFF.

(Re-document size determination process TA12)
The re-original size determination process (TA12) will be described with reference to FIG. In the re-original size determination process (TA12), the original cannot be detected in the blank area when the reading position is the A4 horizontal position LP (No in TA2), but the original cover CV is closed (Yes in TA11). ) When will be started. Therefore, it is started when the document size in the sub-scanning direction is smaller than the A4 landscape.

  The controller CR controls the moving mechanism MM to move the reading unit RU and changes the reading position from the A4 lateral position LP to the reference position BP (TB1). Thereby, in the sub-scanning direction, the reading position of the reading unit RU becomes a position corresponding to the reference side of the document. Here, the “position corresponding to the reference side” means a position slightly shifted to the inside of the document from the reference side (for example, 3 mm inside the reference side).

  The controller CR acquires the gradation value SZB for one line of the lighting line (TB2). That is, the controller CR acquires the gradation value SZB for one line of the lighting line when the document cover CV is closed.

The controller CR determines whether or not the threshold value SZ2 for determining the document size can be calculated (TB3). That is, the controller CR calculates the difference between the gradation value BL2 indicating the intermediate value in the blank area of the gradation value SZB and the gradation value NO2 indicating the intermediate value in the document non-loading area, and the difference is equal to or greater than a predetermined value. If so, it is determined that the threshold value can be calculated (Yes in TB3), and the process proceeds to the threshold value calculation process (TB4). If the difference is smaller than the predetermined value, it is determined that the threshold cannot be calculated (No in TB3), and the process proceeds to the cover open display process (TB6). For example, the predetermined value is 5% of the difference between the white level and the black level. Here, the “intermediate value” refers to the gradation value indicated by the pixel in the middle order when all the pixels in the blank area are arranged in order so that the gradation value becomes large.

  The controller CR calculates a threshold value SZ2 (TB4). Similarly to TA9, the controller CR calculates the average value of the gradation value BL2 and the gradation value NO2, and sets it as the threshold value SZ2. Here, the gradation value BL2 is an intermediate value of the blank area in the gradation value SZ2, but may be an average value of all the pixels in the blank area. Similarly, the gradation value NO2 may be an average value of all the pixels in the document non-placement area.

  The controller CR determines the document size (TB5). Specifically, the controller CR sets the position of the pixel closest to the document non-loading area as the document end portion among the pixels indicating the gradation value smaller than the threshold value SZ2 with respect to the gradation value SZB for one line. to decide. The distance between the reference line and the document edge is determined as the document size in the main scanning direction. The document size is determined from the determined size of the document in the main scanning direction and the size of the document in the sub-scanning direction being smaller than the A4 horizontal. However, if the determined document size in the main scanning direction is different from the standard paper size, the document size in the sub-scanning direction is determined as A3 horizontal.

  The controller CR causes the display unit DM to display an instruction to open the document cover CV (TB6). That is, the controller CR displays to the user an instruction to open the document cover CV.

  The controller CR determines whether ambient light has been detected (TB7). Specifically, the controller CR determines whether or not all digital data of specific pixels in the document non-placement area is equal to or greater than the cover determination value THco. If it is equal to or greater than the cover determination value THco, it is determined that ambient light has been detected (Yes in TB7), and the process proceeds to processing for displaying an instruction to close the document cover CV on the display unit DM (TB10). When it is smaller than the cover determination value THco, it is determined that ambient light is not detected (No in TB7), and the process proceeds to a process (TB8) for determining whether or not a predetermined time has elapsed.

  The controller CR determines whether or not a predetermined time has elapsed (TB8). That is, when the predetermined time has elapsed (Yes in TB8), the controller CR proceeds to a process (TB9) for determining the document size on the side of A3 (TB9), and when the predetermined time has not elapsed (No in TB8), the ambient light The process shifts to a process (TB7) for determining whether or not it is detected. If the ambient light is not detected in TB7, the document cover CV is not opened, so the controller CR determines the document size as A3.

  The controller CR determines the document size on the side of A3 (TB9).

  The controller CR displays an instruction to close the document cover CV on the display unit DM (TB10). That is, the controller CR displays a closing operation instruction for closing the document cover CV to the user.

  The controller CR determines whether or not the document non-loading area is equal to or less than the cover determination value (TB11). That is, the controller CR determines whether or not all the digital data of the specific pixel in the document non-placement area of the light-off line is equal to or less than the cover determination value THco. If it is equal to or less than the cover determination value THco, it is determined that the document cover CV is immediately before being closed (Yes in TB11), and the process proceeds to the line data acquisition process (TB13). If it is larger than the cover determination value THco, it is determined that the document cover CV is open (No in TB11), and the process proceeds to a process (TB12) for determining whether or not a predetermined time has elapsed. Here, “immediately before the document cover CV is closed” is an acquisition timing for acquiring a gradation value for determining the document size. If the result is Yes at TB12, it is determined that the document cover remains open, and the controller CR determines the document size on the side of A3.

  The line data acquisition process (TB13), the threshold value calculation process (TB14), and the document size determination process (TB15) are the same as the processes of TA8, TA9, and TA10, and thus description thereof is omitted. The document size is determined by the processes of TB13, TB14, and TB15.

(Reading process T11)
The reading process (T11) will be described with reference to FIG. The reading process (T11) is started when it is determined that the reading start button is pressed in the process (T10) for determining whether the reading start button is pressed (Yes in T10).

  The controller CR sets a reading range (TC1). Specifically, when the document size is determined by the document size determination process (T9), the controller CR sets the determined document size as the reading range. When the document size confirmation process (T9) is not executed and the document size is not confirmed, the controller CR sets the A3 horizontal size as the reading range.

  The controller CR acquires a setting value at the time of reading from the memory ME (TC2). The set value is a reading resolution or the like. The controller CR sets 300 dpi as the reading resolution.

  The controller CR determines whether or not the cover close flag is ON (TC3). That is, when the controller CR determines that the cover close flag is ON (Yes in TC3), the controller CR proceeds to a process (TC8) for determining whether the reading range in the sub-scanning direction is A4 or more, and the cover close flag is OFF. (No in TC3), the process moves to the home position HP (TC4).

  The controller CR controls the moving mechanism MM to move the reading unit RU and changes the reading position to the home position HP (TC4). Thereby, in the sub-scanning direction, the reading position of the reading unit RU becomes a home position HP that is a position facing the reference member BM.

  The controller CR acquires white data and black data (TC5). Specifically, the controller CR turns off the light source LS, causes the reading unit RU to read one line, and stores the read digital data for one line in the memory ME as black data BK. Further, the controller CR turns on the light source LS with the light amount LE, causes the reading unit RU to read one line, and stores the read digital data for one line in the memory ME as white data WT.

  The controller CR controls the moving mechanism MM to move the reading unit RU and changes the reading position from the home position HP to the reference position BP (TC6). Thereby, in the sub-scanning direction, the reading position of the reading unit RU becomes a position corresponding to the reference side of the document. Here, the “position corresponding to the reference side” means a position slightly shifted to the inside of the document from the reference side (for example, 3 mm inside the reference side).

  The controller CR moves the reading unit RU in the forward direction to execute reading (TC7). Specifically, the controller CR controls the moving mechanism MM to move the reading unit RU over the region from the reference position BP to the reading range set by TC1, and generates image data composed of gradation values. . The “forward direction” is a direction away from the reference point OP in the sub-scanning direction.

  The controller CR determines whether or not the reading range in the sub-scanning direction is A4 horizontal or more (TC8). That is, when the reading range in the sub-scanning direction is A4 horizontal or more (Yes in TC8), the controller CR proceeds to the process of moving to the reading start position (TC10), and the reading range in the sub-scanning direction is from A4 horizontal. Is smaller (No in TC8), the process proceeds to the black data acquisition process (TC9).

  The controller CR acquires black data (TC9). Specifically, the controller CR turns off the light source LS, causes the reading unit RU to read one line, and stores the read digital data for one line in the memory ME as black data BK. When the black data acquisition process (TC9) ends, the process proceeds to the forward reading process (TC7).

  The controller CR controls the moving mechanism MM to move the reading unit RU and changes the reading position to the reading start position (TC10). That is, the controller CR changes the reading position to the reading start position with the position corresponding to the opposite side of the document corresponding to the reading range set in TC1 as the reading start position. When the document cover CV is closed and the document size in the sub-scanning direction is determined to be equal to or larger than A4 horizontal, the document size is fixed at the reading position A4 horizontal position LP. By starting reading from the side, reading can be started in a shorter time.

  The controller CR acquires black data (TC11). Specifically, the controller CR turns off the light source LS, causes the reading unit RU to read one line, and stores the read digital data for one line in the memory ME as black data BK.

  The controller CR moves the reading unit RU in the reverse direction to execute reading (TC12). Specifically, the controller CR controls the moving mechanism MM to move the reading unit RU over a region from the reading start position, which is the opposite side of the document, to the reference position BP, and to convert image data composed of gradation values. Generate. The “reverse direction” is a direction approaching the reference point OP in the sub-scanning direction.

  The controller CR inverts the data with respect to the image data generated by the TC12 (TC13). Specifically, the controller CR is configured so that the last line of the image data before inversion becomes the first line of the image data after inversion, and the first line of the image data before inversion becomes the last line of the image data after inversion. Execute line replacement processing.

(Specific examples of digital data and gradation values in each cover state)
An example in which an A3 landscape document is placed will be described in detail with reference to FIGS. In this embodiment, strong disturbance light is incident on the reading unit RU, and the document has a background color (however, slightly darker than white of the reference member) and a thickness that does not transmit light. Will be described. Further, in the present embodiment, since an A3 landscape document is placed, the document is not placed in the document non-placement area, and the document is placed in other areas. When the cover is closed, the cover is completely closed and there is no influence of ambient light.

  FIG. 7 is a diagram showing the relationship between the main scanning position and the digital data in each cover state. The digital data is a value output from the A / D conversion unit AD. (A) is a state where the cover without a document is closed, (b) is a state where the cover without a document is opened, (c) is a state where the cover with a document is opened, (d) is a state immediately before the cover with a document is closed, (e) is a state where the document is closed Yes The cover is closed. FIG. 1A is a side view of the image reading device SM in FIG. 1B viewed from the left. (2) is a diagram showing the relationship between the main scanning position and the digital data when the light source LS is turned on with the light amount LE, and (3) is the main scanning position and the digital data when the light source LS is turned off. It is a figure which shows the relationship. The two-dot chain line shown in FIG. 7 and FIG. 8 indicates the boundary between the blank area and the document non-placement area with respect to the main scanning position, and the blank area extends from the top pixel position to the two-dot chain line closer to the top pixel. From the two-dot chain line close to the final pixel to the final pixel is a document non-placement area.

  FIG. 8 is a diagram illustrating the relationship between the main scanning position and the gradation value in each cover state. The gradation value is a value output from the correction unit SC. (A)-(e) has shown the presence or absence of a document, and a cover state similarly to FIG. (1) is the side view which looked at image reading device SM which shows a cover state from the side. (2) is a diagram showing the relationship between the main scanning position and the gradation value when the light source LS is turned on with the light amount LE, and (3) is the main scanning position and gradation when the light source LS is turned off. It is a figure which shows the relationship with a value.

  The output results of digital data and gradation values in each cover state will be described with reference to FIGS.

  In the state (a) in which the cover without document is closed, the document cover CV is closed with respect to the main body MB, so that the reading unit RU is not affected by disturbance light. Further, since no document is placed on the image reading device SM, the reading unit RU reads the back surface (white color) of the document cover CV. Therefore, when reading is performed with the light source LS turned on, as shown in (2) of FIG. 7A, the digital data is equivalent to the output when the reference member BM is read, and FIG. As shown in (2), the gradation value is output as the maximum value indicating white. When reading is executed with the light source LS turned off, as shown in (3) of FIG. 7 (a), the digital data becomes an output equivalent to the dark output, as shown in (3) of FIG. 8 (a). In addition, the gradation value is output as a minimum value indicating black.

  When the cover without document is open (b), since the document cover CV is open with respect to the main body MB, the reading unit RU is affected by disturbance light. Furthermore, since no document is placed on the image reading device SM, the reading unit RU is affected by disturbance light in the entire region in the main scanning direction. Therefore, when reading is performed with the light source LS turned on, as shown in (2) of FIG. 7B, the digital data becomes a larger output than when reading the reference member BM due to external light, As shown in (2) of FIG. 8B, the gradation value is output as the maximum value indicating white. Similarly, when reading is performed with the light source LS turned off, as shown in (3) of FIG. 7B, the digital data has a larger output than when the reference member BM is read by external light, and FIG. As shown in (3) of b), the gradation value is output as the maximum value indicating white.

  In the present embodiment, in the process (T8, TB7) for determining whether disturbance light is detected in the power-on process (M1) and the re-original size determination process (TA15) when the cover is open, the controller CR However, it is determined whether or not the digital data in the document non-loading area when the light is off is equal to or greater than the cover determination value THco. That is, as shown in (3) of FIG. 7A, when the cover without document is closed (a), the digital data in the document non-placement area is smaller than the cover determination value THco, and the digital data in FIG. As shown in (3), in the state (b) in which the cover without document is opened, the digital data in the document non-placement area is larger than the cover determination value THco. Using this change in digital data, it is possible to detect the open state of the cover.

  In the state (c) in which the cover with document is open, the document cover CV is open with respect to the main body MB, and thus the reading unit RU is affected by disturbance light. Further, since the document is placed on the image reading device SM, the reading unit RU is affected by disturbance light in the document non-placement region, and is not affected by disturbance light in other regions. Therefore, when reading is performed with the light source LS turned on, as shown in (2) of FIG. 7C, the digital data is more than in the case where the reference member BM is read in the document non-loading area due to disturbance light. In the other areas, the background color of the document is output. As shown in (2) of FIG. 8C, the gradation value is output as the maximum value indicating white in the document non-loading area. In other areas, it is output as the background color. When reading is executed with the light source LS turned off, as shown in (3) of FIG. 7C, the digital data is output larger than the case where the reference member BM is read in the document non-loading area due to disturbance light. In other areas, dark output is output. As shown in (3) of FIG. 8 (c), the gradation value is output as the maximum value indicating white in the document non-placement area. In the area, it is output as the minimum value indicating black.

  In this embodiment, in the process (TA2) for determining whether or not a document is detected in the blank area in the document size determination process (T9), the controller CR turns on and off the light source LS with the light amount LE. It is determined whether or not a document is detected using digital data in the margin area. That is, the difference in digital data between when the light source LS in the blank area is turned off and when the light source LS in the blank area is open (b) is equivalent to 0 as shown by the broken line in (2) of FIG. On the other hand, the difference in the digital data between when the light source LS in the blank area is turned off and when it is turned on in the state where the cover with document is open (c) is as shown by the broken line in (2) of FIG. It is larger than the discrimination value. It is possible to detect a document by using the change in the digital data.

  Unlike the other states, the state (d) immediately before the cover with the document is closed is when the digital data in the document non-placement area becomes equal to or less than the cover determination value THco when the light source LS is turned off and the reading is executed. State. The digital data in the document non-placement area when the light source LS is turned off and reading is performed is influenced by disturbance light when the cover with document is opened (c) and has a large output (FIG. 7). In the state (e) in which the cover with document is closed (see (3) in (c)), a dark output is output without being affected by disturbance light (see (3) in FIG. 7E). On the other hand, the cover determination value THco is a value (T5) calculated by multiplying the maximum value BKmax of the black level BK in the document non-placement area by 1.1, and is equivalent to the black level BK. Therefore, the state when the digital data in the document non-placement area becomes equal to or less than the cover determination value THco is a state in which it is hardly affected by ambient light, and is considered to be immediately before the document cover CV is closed. Can do.

  When reading is performed with the light source LS turned on in the state (d) immediately before the cover with the document is closed, as shown in (2) of FIG. 7D, the digital data is not covered in the document non-loading area. The vicinity of the judgment value THco is output, and the background color is output in other areas. As shown in (2) of FIG. 8D, the gradation value is corrected to the cover judgment value THco in the document non-placement area. The vicinity of the selected value is output, and in other areas, it is output as the background color. When reading is executed with the light source LS turned off, as shown in (3) of FIG. 7D, the digital data is output in the vicinity of the cover determination value THco in the document non-loading area, and the other areas. Then output dark output. As shown in (3) of FIG. 8D, the gradation value is output in the vicinity of the corrected value of the cover determination value THco in the document non-placement area, and is output as the minimum value indicating black in the other areas. Is done.

  In the present embodiment, the controller CR determines whether or not the document non-placement area in the document size determination process (T9) and the re-document size determination process (TA15) is equal to or less than the cover determination value (TA5, TB11). It is determined whether or not all the digital data of the specific pixel in the document non-placement area of the light-off line is equal to or less than the cover determination value THco. That is, as shown in (3) of FIG. 7C, the digital data is output larger than when reading the reference member BM due to the influence of disturbance light in the document non-mounting area when the document cover CV is opened. Is output. As shown in (3) of FIG. 7D, the digital data is not easily affected by the disturbance light in the document non-placement area immediately before the document cover CV is closed, and outputs the vicinity of the cover determination value THco. ing. Therefore, the digital data in the document non-placement area changes depending on the state of the document cover CV. Using this change, it is possible to detect a state immediately before the document cover CV is closed.

  In the present embodiment, in the document size determination processing (TA10, TB15) in the document size determination processing (T9) and the re-document size determination processing (TA15), the controller CR is a gradation when the light source LS is lit with the light amount LE. The size in the main scanning direction is determined using the value. That is, as shown in (2) of FIG. 8D, in the area where no document is placed, the gradation value is the minimum value indicating black when the light source LS is turned on and reading is performed. Is output. On the other hand, in the area where the original is present, the reading result of the original is output as the gradation value. Therefore, the document edge facing the reference line in the main scanning direction is in the document non-placed area out of the values larger than the threshold value SZ1 obtained from the gradation value of the margin area and the gradation value of the document non-placed area. Close position. In the present embodiment, the boundary of the document non-loading area is the document end facing the reference line. In this way, by using the gradation value, variations that occur in the case of digital data can be eliminated, and the document edge can be accurately determined. Here, “variation occurring in the case of digital data” means that in digital data, values representing the same gradation are different for each pixel.

  In the state (e) in which the cover with document is closed, the document cover CV is closed with respect to the main body MB, so that it is not affected by disturbance light. Since the document is placed on the image reading device SM, the reading unit RU reads the document in the area where the document is placed, and reads the back side of the white document cover CV in the area where the document is not placed. become. Therefore, when reading is executed with the light source LS turned on, as shown in (2) of FIG. 7E, the digital data is output corresponding to white in the document non-loading area, and in the other areas. The output corresponds to the background color, and as shown in (2) of FIG. 8E, the gradation value is output as the maximum value indicating white in the document non-placement area, and as the background color in other areas. Is output. When reading is executed with the light source LS turned off, as shown in (3) of FIG. 7 (e), the digital data becomes an output equivalent to the dark output, as shown in (3) of FIG. 8 (e). In addition, the gradation value is output as a minimum value indicating black.

  In the present embodiment, in the process (TA12) for determining whether or not the cover is closed in the document size determination process (T9), the controller CR determines that the digital data in the document non-mounting area when the light is off is equal to or less than the cover determination value THco. Judgment whether or not. That is, as shown in (3) of FIG. 7E, in the state (e) where the cover with document is closed, the digital data in the document non-placement area is smaller than the cover determination value THco. Using this digital data, it is possible to detect the closed state of the cover.

<Effect of embodiment>
In the present embodiment, in the process (TA5) for determining whether or not the document non-placement area is equal to or smaller than the cover determination value THco in the document size determination process (T9), the digital data in the document non-placement area is the cover determination value THco. It is repeatedly determined whether or not it is less than or equal to a predetermined time (No in TA6). Therefore, by repeatedly determining, the document cover CV can be detected even if a predetermined time has not elapsed, and the state change of the document cover can be detected quickly, and as a result, the timing immediately before the document cover is closed is generated. Can do.

  In this embodiment, in the process (T6) of moving to the A4 horizontal position in the power-on process (M1), after changing the reading position to the A4 horizontal position LP, the document non-placement area in the document size determination process (T9) The process (TA5) for determining whether or not the cover determination value THco is equal to or less than is performed. Therefore, since the reading position is sufficiently away from the end of the transparent plate TP in the sub-scanning direction, the disturbance light is not affected by the main body MB and is blocked by the document cover. As a result, it is possible to accurately detect the state of the document cover.

[Correspondence between embodiment and invention]
The image reading device SM, the document placing table DT, and the document cover CV are examples of the image reading device, the document placing table, and the document cover of the present invention. Light source LS, a reading unit RU, A / D conversion unit AD, the correction unit SC, the moving mechanism MM, our and the controller CR light source of the present invention, the reading unit, reading mechanism, which is an example of a contact and the controller. The process (T6) for changing the reading position from the home position HP to the A4 horizontal position LP is an example of the changing process of the present invention. The process (T8) for determining whether ambient light has been detected is an example of the open determination process of the present invention. Process of determining whether or not the following cover determination value at originals non-placing area (TA5) is an example of a closing determination process of the present invention. The process (TA1) for performing the lighting control of the light source LS during the document size determination process is an example of the lighting process of the present invention. The process (TA2) for determining whether or not a document is detected in the margin area is an example of the document determination process of the present invention.

[Modification]
The present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention. An example of the modification will be described below.

  (1) The reading mechanism RM of the present embodiment may not have a configuration using the CIS, and may have a configuration using a moving mirror that fixes a CCD (Charge Coupled Device), for example. In this case, the “reading position” is not the position of the image sensor but the position of the mirror.

  (2) In the present embodiment, the controller CR determines the state of the document cover CV using the digital data at the A4 lateral position LP (Yes in TA5), but the reading unit RU may detect disturbance light. If it is possible, the state of the document cover CV can be determined.

  (3) In this embodiment, the controller CR uses the digital data to determine the state of the document cover CV (Yes in TA5). However, instead of using the digital data, the controller CR determines the state of the document cover CV. You may judge.

  (4) In the present embodiment, the controller CR determines the document size using the gradation value (TA10). However, the controller CR may determine the document size using digital data instead of the gradation value.

  (5) In the present embodiment, the controller CR performs the process (TA10) for determining the document size after determining the state of the document cover CV (Yes in TA5), but has detected the state of the document cover CV. Later, an initialization process of the reading process may be performed.

  (6) In the present embodiment, the controller CR determines the state of the document cover CV using the digital data in the document non-placement area (Yes in TA5), but the document is not placed in the document non-placement area. If the area is not removed, the state of the document cover CV can be determined.

  (7) In this embodiment, the cover determination value THco is a value calculated by multiplying the black data maximum value BKmax, which is the maximum value of the data in the non-document placement area of the black data BK, by 1.1. The maximum value of all data of the black data BK may be set as the cover determination value THco, or the cover determination value THco may be calculated from the black data BK and the white data WT.

Claims (3)

An image reading device,
A document placement table provided with a reference point on which one vertex of a document to be read is to be placed and having a document non-mounting area where the document is not supported;
A document cover that opens and closes to a closed state that covers the top surface of the document table and an open state that opens the top surface of the document table ;
A light source that emits light;
A reading unit that performs reading to acquire the amount of light received in units of lines along the main scanning direction as digital data;
A reading mechanism that changes a reading position for performing the reading in a sub-scanning direction orthogonal to the main scanning direction;
A controller, and
The controller is
A change process for changing the reading position by the reading mechanism to a detection position where the reading unit detects disturbance light in the document non-loading area;
In a state where the reading position is changed to the detection position, light is not emitted from the light source, and the document cover is open when digital data in the document non-loading area in the main scanning direction is equal to or greater than a cover determination value. Open determination processing to determine that there is,
After the document cover is determined to be in the open state in the open determination process, the document is not placed in the main scanning direction without irradiating light from the light source in a state where the reading position is changed to the detection position. A close determination process for determining that the document cover is in a closed state when digital data of an area is equal to or less than the cover determination value ;
The image reading apparatus characterized by performing. The document table includes, as a blank area, an area from a reference line parallel to the sub-scanning direction passing through the reference point to a position separated by a predetermined distance in the main scanning direction.
The controller is
A lighting process for controlling the light source with two lines combining a lighting line for irradiating light from the light source and a light-off line for turning off the light source as a reading line;
After it is determined in the open determination process that the document cover is in an open state, a difference between the digital data of the lighting line in the blank area and the digital data of the extinguished line in the blank area is larger than the document determination value. A document determination process for determining that the document is supported in the margin area ,
The image reading apparatus according to claim 1, wherein the closing determination process is executed after it is determined in the document determination process that the document is supported in the blank area . A method performed by an image reading apparatus, comprising:
The image reading device includes:
A document placement table provided with a reference point on which one vertex of a document to be read is to be placed and having a document non-mounting area on which a document is not placed;
A document cover that opens and closes to a closed state that covers the top surface of the document table and an open state that opens the top surface of the document table ;
A light source that emits light;
A reading unit that performs reading to acquire the amount of light received in units of lines along the main scanning direction as digital data;
A reading mechanism for changing the reading position for executing the reading in the sub-scanning direction,
The method
A change step of changing the reading position by the reading mechanism to a detection position where the reading unit detects disturbance light in the document non-loading area;
In a state where the reading position is changed to the detection position, light is not emitted from the light source, and the document cover is open when digital data in the document non-loading area in the main scanning direction is equal to or greater than a cover determination value. An open determination process for determining that there is,
After the document cover is determined to be in the open state in the open determination process, the document is not placed in the main scanning direction without irradiating light from the light source in a state where the reading position is changed to the detection position. A closing determination step of determining that the document cover is in a closed state when digital data of an area is equal to or less than the cover determination value;
Including methods.

Images