Image reading device

Abstract

To provide an image reading device that can improve the accuracy of determining an open and closed state of a cover without using a sensor that detects the open and closed state of the cover.SOLUTION: An image reading device comprises: a cover part that is openable and closeable in a predetermined section of a conveyance path; a reading device having a light source, and a sensor that detects light from the light source radiated and reflected on a document to obtain a read value; and a control unit that controls the operation of a reading device. The control unit includes: an acquisition unit that acquires a read value in a main scanning direction with the light source being turned off as first data, and a read value in the main scanning direction with the light source being turned on as second data; a first calculation unit that calculates a first evaluation value based on a plurality of portions of the first data, and calculates a second evaluation value based on a plurality of portions of the second data; and a determination unit that determines an open and closed state of the cover part based on the first evaluation value, determines the open and closed state of the cover part based on the second evaluation value, when at least one of a determination result based on the first evaluation value and a determination result based on the second evaluation value indicates the open state, determines that the cover part is in the open state, and when both indicate the closed state, determines that the cover part is in the closed state.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an image reading apparatus.

Background Art

[0002] There is known a so-called sheet-through type image reading apparatus that performs document conveyance by an ADF (Automatic Document Feeder) and reads a document. In such an image reading apparatus, there is an openable and closable cover on the document conveyance path so that the user can take out the document manually when paper jams occur.

[0003] In an ADF having such an openable and closable cover, if the reading operation of the document is performed with the cover open, problems such as an abnormal image being obtained or damage being caused to the document may occur. Therefore, a configuration in which a sensor capable of detecting the open / closed state of the cover is mounted and the reading operation is performed only when the cover is in the closed state can be considered. However, a configuration having a sensor capable of detecting the open / closed state of the cover has problems in that it is complicated and the cost increases. In order to solve such problems, a technique for detecting the opening and closing of the cover of an image reading apparatus without using a sensor capable of detecting the open / closed state of the cover has been disclosed for the purpose of simplifying the configuration and reducing the cost.

[0004] As a technique for detecting the opening and closing of the cover of an image reading apparatus without using a sensor capable of detecting the open / closed state of the cover, a configuration for determining the open / closed state based on the maximum value, minimum value, or fluctuation width in the main scanning direction of the amount of light received by a CCD when light from a lamp is irradiated toward an opening / closing body (cover) has been disclosed (for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the technology described in Patent Document 1 utilizes the principle that when the cover is open, the distance between the sensor and the background plate increases, preventing reflected light from the background plate from entering the sensor and thus reducing the sensor's output. However, if there is strong ambient light such as fluorescent lights in the room, the sensor's output may increase, which could lead to misjudgments.

[0006] The present invention has been made in view of the above, and aims to provide an image reading device that can improve the accuracy of determining the open / closed state of a cover without using a sensor to detect the open / closed state of the cover. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the present invention provides an image reading device for transporting a document and reading an image of the document, comprising: a reading device having a cover portion that can be opened and closed over a predetermined section of the document transport path; a light source; and a sensor that detects reflected light from the light source onto the document and obtains a reading value; and a control device that controls the operation of the reading device, wherein the control device acquires the reading value in the main scanning direction obtained by detection by the sensor with the light source turned off as first data, and acquires the reading value in the main scanning direction obtained by detection by the sensor with the light source turned on as second data The system comprises: an acquisition unit that acquires data; a first calculation unit that calculates a first evaluation value based on data from multiple locations in the main scanning direction in the first data, and a second evaluation value based on data from multiple locations in the main scanning direction in the second data; and a determination unit that determines the open / closed state of the cover based on the first evaluation value, determines the open / closed state of the cover based on the second evaluation value, determines that the cover is in an open state if at least one of the determination results based on the first evaluation value and the determination results based on the second evaluation value indicates an open state, and determines that the cover is in a closed state if both indicate a closed state. Furthermore, if the determination unit determines that the cover is in a closed state based on the first evaluation value, but determines that the cover is in an open state based on the second evaluation value, the determination unit determines that the cover is in an open state. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, the accuracy of determining the open / closed state of the cover can be improved without using a sensor to detect the open / closed state of the cover. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an example of the overall structure of the image reading device according to the first embodiment. [Figure 2] Figure 2 shows an example of the hardware configuration of the control device and reading module according to the first embodiment. [Figure 3] Figure 3 shows an example of the configuration of a functional block of the control device according to the first embodiment. [Figure 4] Figure 4 illustrates the operation of calculating a black evaluation value from black data in the control device according to the first embodiment. [Figure 5] Figure 5 illustrates the operation of performing threshold determination on the black evaluation value in the control device according to the first embodiment. [Figure 6] Figure 6 illustrates an example of the threshold determination state for the black evaluation value when the cover is wide open in the image reading device according to the first embodiment. [Figure 7] Figure 7 illustrates an example of the threshold determination state for the black evaluation value in the image reading device according to the first embodiment, when the cover is half-open. [Figure 8] Figure 8 illustrates the operation of calculating a white evaluation value from white data in the control device according to the first embodiment. [Figure 9] Figure 9 illustrates the operation of performing threshold determination on the white evaluation value in the control device according to the first embodiment. [Figure 10] Figure 10 illustrates an example of the threshold determination state for the white evaluation value when the cover is floating in the image reading device according to the first embodiment. [Figure 11]Figure 11 illustrates an example of the threshold determination state for the white evaluation value when the cover is slightly raised in the image reading device according to the first embodiment. [Figure 12] Figure 12 shows an example of the configuration of a functional block of a control device according to the second embodiment. [Figure 13] Figure 13 shows an example of the configuration of a functional block of a control device according to Modification 1 of the second embodiment. [Figure 14] Figure 14 shows an example of the configuration of a functional block of a control device according to a modified example 2 of the second embodiment. [Figure 15] Figure 15 shows an example of the configuration of a functional block of a control device according to a modified example 3 of the second embodiment. [Figure 16] Figure 16 shows an example of the configuration of a functional block of a control device according to the third embodiment. [Figure 17] Figure 17 shows an example of the configuration of a functional block of the control device according to the fourth embodiment. [Figure 18] Figure 18 is a flowchart showing an example of the operation flow for differentiating between a cover open state and other abnormalities in the image reading device according to the fifth embodiment. [Figure 19] Figure 19 is a flowchart showing an example of the operation flow for reusing black data and white data in the image reading device according to the sixth embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the image reading device according to the present invention will be described in detail below with reference to the drawings. Furthermore, the present invention is not limited by the following embodiments, and the components in the following embodiments include those that are easily conceivable by those skilled in the art, substantially identical, and so-called equivalents. Moreover, various omissions, substitutions, modifications, and combinations of components can be made without departing from the spirit of the following embodiments.

[0011] [First Embodiment] (Overview of the overall structure of the image reading device) FIG. 1 is a diagram showing an example of an overview of the overall structure of an image reading device according to the first embodiment. While referring to FIG. 1, the overview of the overall structure of the image reading device 1 according to the present embodiment will be described.

[0012] The image reading device 1 shown in FIG. 1 is a sheet-through type image reading device that performs a reading operation on a document by transporting the document by an ADF. As shown in FIG. 1, the image reading device 1 includes a cover 11 (cover unit), a transport path 12, an inlet roller 13, a transport roller 14, a transport roller 15, a pressure roller 15a, an outlet roller 16, a reading module 17, and a control device 18.

[0013] The cover 11 is a cover member that opens and closes to block external light in a predetermined section on the transport path 12. The cover 11 has a white background plate 11a at a position facing the reading module 17. The "white data" described later is the image data of the background plate 11a.

[0014] The transport path 12 is a path indicated by a dotted line in FIG. 1 along which a document to be read is transported. The inlet roller 13 is a roller for transporting the set document onto the transport path 12. The transport roller 14 is a roller for transporting the document transported by the inlet roller 13 to the reading position of the reading module 17.

[0015] The transport roller 15 is a roller that transports the document in the circumferential direction by transmitting the rotational force of the transport roller 15 to the document by pressure contact with a driven pressure roller 15a for the document on which reading processing has been performed by the reading module 17. The outlet roller 16 is a roller for discharging the document transported by the transport roller 15 outside the image reading device 1.

[0016] The reading module 17 is a reading device that performs reading processing on a document being transported at a predetermined reading position on the transport path 12. As shown in Figure 1, the reading module 17 includes a light source 170 that emits light and an image reading sensor 171 that detects the reflected light emitted from the light source 170. The image reading sensor 171 detects the reflected light from the document emitted by the light source 170, thereby reading the image of the document.

[0017] The control device 18 is a controller that controls the operation of the reading module 17. The control device 18 also receives data (read values) (black data and white data described later) read by the reading module 17 and determines the open / closed state of the cover 11 based on this data.

[0018] As shown in Figure 1, when the cover 11 is opened, the distance between the background plate 11a and the reading module 17 increases.

[0019] (Hardware configuration of the control unit and reading module) Figure 2 shows an example of the hardware configuration of the control device and reading module according to the first embodiment. The hardware configuration of the control device 18 and reading module 17 of the image reading device 1 according to this embodiment will be described with reference to Figure 2.

[0020] As shown in Figure 2, the reading module 17 includes a light source 170, an image reading sensor 171, and an A / D conversion circuit 172.

[0021] Light source 170 is a light source such as an LED (Light Emitting Diode) that emits light.

[0022] The image reading sensor 171 is a reading sensor such as a CCD (Charge-Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) that detects reflected light from the light source 170. The image reading sensor 171 transmits the analog data obtained through the reading process to the A / D conversion circuit 172.

[0023] The A / D conversion circuit 172 is an electronic circuit that converts analog data obtained by the reading process of the image reading sensor 171 into digital data (reading value) and outputs it to the control device 18.

[0024] In this embodiment, before the document scanning process, with the light source 170 turned off, the analog data obtained by scanning the image reading sensor 171 in at least the main scanning direction is converted by the A / D conversion circuit 172, and this converted digital data is acquired by the control device 18 as "black data". Also, before the document scanning process, with the light source 170 turned on, the analog data obtained by scanning the image reading sensor 171 in at least the main scanning direction is converted by the A / D conversion circuit 172, and this converted digital data is acquired by the control device 18 as "white data". Note that the black data and white data may include not only data from the main scanning direction but also data from the sub-scanning direction.

[0025] As shown in Figure 2, the control device 18 includes a CPU (Central Processing Unit) 180, a memory 181, and an I / F circuit 182.

[0026] The CPU 180 is an arithmetic unit that controls the overall operation of the control device 18. For example, the CPU 180 acquires black data and white data from the reading module 17 via the I / F circuit 182, and performs processes such as determining the open / closed state of the cover 11 based on the black data and white data.

[0027] Memory 181 is a non-volatile storage device that stores programs executed by CPU 180 and various data.

[0028] The I / F circuit 182 is an interface circuit that controls the input and output of data. For example, the I / F circuit 182 receives image data (including black data and white data) acquired by the reading process of the reading module 17.

[0029] Note that the hardware configuration of the reading module 17 and control device 18 shown in Figure 2 is just one example, and other components may also be included.

[0030] (Configuration of the control unit's functional blocks) Figure 3 shows an example of the configuration of the functional block of the control device according to the first embodiment. The configuration of the functional block of the control device 18 according to this embodiment will be described with reference to Figure 3.

[0031] As shown in Figure 3, the control device 18 includes an acquisition unit 201, an arithmetic processing unit 202 (an example of a first calculation unit), and a cover opening / closing determination unit 203 (determination unit).

[0032] The acquisition unit 201 is a functional unit that acquires black data (first data) and white data (second data) from the reading module 17 via the I / F circuit 182. The acquisition unit 201 is implemented, for example, by a program executed by the CPU 180 shown in Figure 2.

[0033] The arithmetic processing unit 202 is a functional unit that calculates a black evaluation value (first evaluation value) and a white evaluation value (second evaluation value) used in the process of determining the open / closed state of the cover 11, respectively, from the black data and white data acquired by the acquisition unit 201. The arithmetic processing unit 202 is implemented, for example, by a program executed by the CPU 180 shown in Figure 2.

[0034] The cover opening / closing determination unit 203 is a functional unit that uses the black evaluation value and white evaluation value calculated by the arithmetic processing unit 202 to determine the opening / closing state of the cover 11. The cover opening / closing determination unit 203 then outputs the determination result of the determination process. The cover opening / closing determination unit 203 is implemented, for example, by a program executed by the CPU 180 shown in Figure 2.

[0035] Furthermore, some or all of the acquisition unit 201, the arithmetic processing unit 202, and the cover opening / closing determination unit 203 may be implemented not by a software program, but by an integrated circuit such as an FPGA (Field-Programmable Gate Array) or ASIC.

[0036] Furthermore, the acquisition unit 201, arithmetic processing unit 202, and cover opening / closing determination unit 203 shown in Figure 3 are conceptual representations of their functions and are not limited to this configuration. For example, the multiple functional units shown as independent functional units in the control device 18 in Figure 3 may be configured as a single functional unit. Alternatively, the functions of a single functional unit in the control device 18 shown in Figure 3 may be divided into multiple functions and configured as multiple functional units.

[0037] (Process to determine the open / closed state of the cover) Figure 4 illustrates the operation of calculating a black evaluation value from black data in the control device according to the first embodiment. Figure 5 illustrates the operation of performing threshold determination on the black evaluation value in the control device according to the first embodiment. Figure 6 illustrates an example of the threshold determination state for the black evaluation value when the cover is wide open in the image reading device according to the first embodiment. Figure 7 illustrates an example of the threshold determination state for the black evaluation value when the cover is half open in the image reading device according to the first embodiment. Figure 8 illustrates the operation of calculating a white evaluation value from white data in the control device according to the first embodiment. Figure 9 illustrates the operation of performing threshold determination on the white evaluation value in the control device according to the first embodiment. Figure 10 illustrates an example of the threshold determination state for the white evaluation value when the cover is slightly raised in the image reading device according to the first embodiment. Figure 11 illustrates an example of the threshold determination state for the white evaluation value when the cover is slightly raised in the image reading device according to the first embodiment. The process of determining the open / closed state of the cover 11 by the control device 18 will be explained with reference to Figures 4 to 11.

[0038] First, referring to Figures 4 to 7, we will explain the process for determining the open / closed state of the cover 11 using black data.

[0039] The black data described above is image data read by the reading module 17 with the light source 170 turned off before the document scanning process, as shown in Figure 4(a). The graph of black data shown in Figure 4(a) has the horizontal axis representing the main scanning direction and the vertical axis representing the image level. Here, the image level refers to the pixel value or brightness value of the image data. The arithmetic processing unit 202 divides the black data acquired by the acquisition unit 201 into predetermined intervals in the main scanning direction and calculates the black evaluation value for each interval, as shown in Figure 4(b). The method for calculating the black evaluation value may be, for example, the peak value of the black data in each interval, the average value, the median value of the interval, or the peak value, average value, or median value extended not only to the main scanning direction but also to the sub-scanning direction.

[0040] The cover opening / closing determination unit 203 then determines the open / closed state of the cover 11 by performing a threshold determination on the black evaluation value. Specifically, as shown in Figure 5, upper and lower threshold values ​​(first threshold) are set in advance for each section in the main scanning direction, and the cover opening / closing determination unit 203 determines whether the black evaluation value in each section in the main scanning direction falls within the range between the upper and lower threshold values. If the black evaluation value falls within the range in all sections, it is determined that the cover 11 is in a closed state. Here, the upper and lower threshold values ​​may be predetermined percentages of the black evaluation value obtained in advance when the cover 11 is in a closed state, or they may be values ​​calculated considering changes over time or variations. Furthermore, the range between the upper and lower threshold values ​​mentioned above will be referred to as the threshold range.

[0041] Referring to Figure 6, the determination process by the cover opening / closing determination unit 203 when the cover 11 is wide open will be explained. As shown in Figure 6(a), when the cover 11 is wide open, ambient light is directly incident on the reading module 17, so as shown in Figure 6(b), the black evaluation value becomes large overall, and all values ​​deviate from the threshold range. In this case, the cover opening / closing determination unit 203 determines that the cover 11 is in the open state.

[0042] Next, with reference to Figure 7, the determination process by the cover opening / closing determination unit 203 when the cover 11 is half-open will be explained. As shown in Figure 7(a), when the cover 11 is half-open, some ambient light is incident on the reading module 17. As a result, as shown in Figure 7(b), the black evaluation value becomes large in a portion of the main scanning direction, and the value in that portion exceeds the threshold range and deviates (the portion within the dotted line in Figure 7(b)). Even in this case, the cover opening / closing determination unit 203 determines that the cover 11 is in an open state. Note that depending on the component layout, some parts may be in shadow and ambient light may not enter, resulting in a state like Figure 7(b) even when the cover 11 is wide open.

[0043] Next, referring to Figures 8 to 11, we will explain the process for determining the open / closed state of the cover 11 using white data.

[0044] The white data described above is image data read by the reading module 17 with the light source 170 lit before the document scanning process, as shown in Figure 8(a). The graph of white data shown in Figure 8(a) has the horizontal axis representing the main scanning direction and the vertical axis representing the image level. The arithmetic processing unit 202 divides the white data acquired by the acquisition unit 201 into predetermined intervals in the main scanning direction and calculates the white evaluation value for each interval, as shown in Figure 8(b). The method for calculating the white evaluation value may be, for example, the peak value of the white data in each interval, the average value, or the peak value or average value extended not only to the main scanning direction but also to the sub-scanning direction.

[0045] The cover opening / closing determination unit 203 then determines the open / closed state of the cover 11 by performing a threshold determination on the white evaluation value. Specifically, as shown in Figure 9, upper and lower threshold values ​​(second thresholds) are set in advance for each section in the main scanning direction, and the cover opening / closing determination unit 203 determines whether the white evaluation value in each section in the main scanning direction falls within the range between the upper and lower threshold values. If the white evaluation value falls within the range in all sections, it is determined that the cover 11 is in a closed state. Here, the upper and lower threshold values ​​may be predetermined percentages of the white evaluation value obtained in advance when the cover 11 is in a closed state, or they may be values ​​calculated considering changes over time or variations. Furthermore, the range between the upper and lower threshold values ​​mentioned above will be explained as the threshold range.

[0046] Referring to Figure 10, the determination process by the cover opening / closing determination unit 203 when the cover 11 is floating will be explained. As shown in Figure 10(a), when the cover 11 is floating, the distance between the reading module 17 and the background plate 11a increases, and the background plate 11a moves out of the focal position of the image reading sensor 171. As a result, as shown in Figure 10(b), the white evaluation values ​​become smaller overall, and all values ​​deviate from the threshold range. In this case, the cover opening / closing determination unit 203 determines that the cover 11 is in the open state.

[0047] Next, with reference to Figure 11, the determination process by the cover opening / closing determination unit 203 when the cover 11 is slightly lifted will be explained. As shown in Figure 11(a), when the cover 11 is slightly lifted, the distance between the reading module 17 and the background plate 11a increases slightly, and in some sections the background plate 11a is out of focus of the image reading sensor 171. As a result, as shown in Figure 11(b), the white evaluation value becomes smaller in some sections of the main scanning direction, and the value in those sections deviates from the threshold range (the area within the dotted line in Figure 11(b)). Even in this case, the cover opening / closing determination unit 203 determines that the cover 11 is in the open state.

[0048] As described above, the cover opening / closing determination unit 203 determines the open / closed state of the cover 11 based on the black evaluation value calculated by the calculation processing unit 202, and further determines the open / closed state of the cover 11 based on the white evaluation value. If the cover opening / closing determination unit 203 determines that at least one of the determination results of the open / closed state of the cover 11 based on the black evaluation value and the determination result of the open / closed state of the cover 11 based on the white evaluation value indicates that the cover 11 is in an open state, it makes a final determination that the cover 11 is in an open state. On the other hand, if the cover opening / closing determination unit 203 determines that both the determination results of the open / closed state of the cover 11 based on the black evaluation value and the determination result of the open / closed state of the cover 11 based on the white evaluation value indicate that the cover 11 is in a closed state, it makes a final determination that the cover 11 is in a closed state.

[0049] As described above, in the image reading device 1 according to this embodiment, the cover 11 can be opened and closed in relation to a predetermined section of the document transport path 12, the reading module 17 has a light source 170 and an image reading sensor 171 that detects the reflected light of the light source 170 irradiated onto the document to obtain a reading value, the control device 18 controls the operation of the reading module 17, the acquisition unit 201 of the control device 18 acquires the reading value in the main scanning direction obtained by detection by the image reading sensor 171 as black data when the light source 170 is turned off, and acquires the reading value in the main scanning direction obtained by detection by the image reading sensor 171 as white data when the light source 170 is turned on The data is acquired as black data, and the arithmetic processing unit 202 of the control device 18 calculates black evaluation values ​​based on data at multiple locations in the main scanning direction in the black data, and calculates white evaluation values ​​based on data at multiple locations in the main scanning direction in the white data. The cover opening / closing determination unit 203 of the control device 18 determines the opening / closing state of the cover 11 based on the black evaluation value and the white evaluation value. If at least one of the determination results based on the black evaluation value and the determination result based on the white evaluation value indicates an open state, the cover 11 is determined to be in an open state. If both indicate a closed state, the cover 11 is determined to be in a closed state. By using these two types of determinations to determine the final opening / closing state of the cover 11, the accuracy of determining the opening / closing state of the cover 11 can be improved without using a sensor to detect the opening / closing state of the cover 11 itself. As a result, even if the cover 11 is in a half-open state or in a special state such as strong ambient light, the cover 11 can be accurately determined to be open or closed.

[0050] [Second Embodiment] The image reading device 1 according to the second embodiment will be described, focusing on the differences from the image reading device 1 according to the first embodiment. In this embodiment, a reference value is stored in the storage unit in advance, and the operation of calculating a threshold value for determining the open / closed state of the cover 11 from the reference value will be described. The overall configuration of the image reading device 1 according to this embodiment, as well as the hardware configuration of the control device and reading module 17, are the same as those described in the first embodiment.

[0051] (Configuration of the control unit's functional blocks) Figure 12 is a diagram showing an example of the configuration of the functional block of the control device according to the second embodiment. The configuration of the functional block of the control device 18a according to this embodiment will be described with reference to Figure 12.

[0052] As shown in Figure 12, the control device 18a includes an acquisition unit 201, an arithmetic processing unit 202a (an example of a first calculation unit), a cover opening / closing determination unit 203 (determination unit), and a storage unit 204. The operation of the acquisition unit 201 and the cover opening / closing determination unit 203 is the same as in the first embodiment described above.

[0053] The memory unit 204 is a functional unit that pre-stores reference values ​​used for threshold calculation by the arithmetic processing unit 202a. Specifically, the memory unit 204 stores reference values ​​for determining the thresholds used for threshold determination of the black evaluation value and the white evaluation value, respectively. Here, the reference value corresponding to the black evaluation value corresponds to the "first reference value," and the reference value corresponding to the white reference value corresponds to the "second reference value." The same applies to the various modifications described later. The memory unit 204 is implemented by the memory 181 shown in Figure 2.

[0054] The arithmetic processing unit 202a includes a threshold calculation unit 212 (an example of a second calculation unit).

[0055] The threshold calculation unit 212 reads a reference value from the storage unit 204 and calculates thresholds to be used for the determination process of the cover opening / closing determination unit 203, i.e., for threshold determination of the black evaluation value and the white evaluation value, based on the reference value. Here, the threshold for the black evaluation value corresponds to the "first threshold," the threshold for the white evaluation value corresponds to the "second threshold," and so on. For example, the threshold calculation unit 212 may calculate a threshold value that is a predetermined percentage of the reference value, or it may calculate a threshold value that is obtained by adding or subtracting a predetermined value from the reference value.

[0056] The reference values ​​stored in the memory unit 204 may be, for example, the black evaluation value and white evaluation value measured at the time of factory shipment, or they may be values ​​that are rewritten in the memory unit 204 each time the black evaluation value and white evaluation value at the time the cover 11 is determined to be in the closed state are used.

[0057] Furthermore, the acquisition unit 201, arithmetic processing unit 202a, cover opening / closing determination unit 203, and storage unit 204 shown in Figure 12 are conceptual representations of their functions and are not limited to this configuration. For example, multiple functional units shown as independent functional units in the control device 18a shown in Figure 12 may be configured as a single functional unit. Alternatively, the functions of a single functional unit in the control device 18a shown in Figure 12 may be divided into multiple functions and configured as multiple functional units.

[0058] With the above configuration, the cover opening / closing determination unit 203 can perform the determination process for the open / closed state of the cover 11 under the same conditions each time, thereby suppressing situations in which the cover is mistakenly determined to be in a closed state and a reading operation is performed due to aging or abnormalities in the light source 170.

[0059] (Variation 1) Next, as a modification 1 of the second embodiment, we will describe an operation in which a unique reference value for each unit of the image reading device 1 is stored in the memory unit in advance, and a threshold value for determining the open / closed state of the cover 11 is calculated from the said reference value.

[0060] Figure 13 is a diagram showing an example of the configuration of the functional block of the control device according to Modification 1 of the second embodiment. The control device 18a according to this modification will be described with reference to Figure 13. The block configuration of the control device 18a is the same as the block configuration of the control device 18a shown in Figure 12 above.

[0061] If the reference value stored in the memory unit 204 is a fixed value common to multiple image reading devices 1, there is a possibility of misjudgment regarding the open / closed state of the cover 11 in a particular device due to variations in the configuration of each device. Therefore, in this modified example, the memory unit 204 stores a reference value unique to each image reading device 1 (each individual device) in advance. The reference value corresponding to each device stored in the memory unit 204 may be, for example, the black evaluation value and white evaluation value measured for each device at the time of factory shipment.

[0062] With the above configuration, it is possible to suppress the occurrence of misjudgments of the open / closed state of the cover 11 caused by variations between individual aircraft.

[0063] (Modification 2) Next, as a modification 2 of the second embodiment, we will describe an operation in which a value is calculated from a reference value stored in the memory unit in advance, taking into account the change over time in the characteristics of the light source 170 or the image reading sensor 171, and a threshold value for determining the open / closed state of the cover 11 is calculated from that value.

[0064] Figure 14 is a diagram showing an example of the configuration of the functional block of the control device according to Modification 2 of the second embodiment. The configuration of the functional block of the control device 18b according to this modification will be described with reference to Figure 14.

[0065] As shown in Figure 14, the control device 18b includes an acquisition unit 201, an arithmetic processing unit 202b (an example of a first calculation unit), a cover opening / closing determination unit 203 (determination unit), and a storage unit 204. The operation of the acquisition unit 201, the cover opening / closing determination unit 203, and the storage unit 204 is the same as in the modified example 1 described above.

[0066] The calculation processing unit 202b includes a threshold calculation unit 212 (an example of a second calculation unit) and a time-dependent change calculation unit 213 (a third calculation unit).

[0067] If the reference value stored in the memory unit 204 is a fixed value, and the threshold value is similarly set to a non-changing value, then when the characteristics of at least one of the light source 170 or image reading sensor 171 mounted on the reading module 17 change over time, there is a possibility of misjudging the open / closed state of the cover 11. For example, in the case of the light source 170, as time passes, the light intensity decreases, and consequently, the white evaluation value also decreases. If threshold determination is performed using this white evaluation value, there is a possibility of misjudging the cover 11 as open even when it is closed. Therefore, in this modified example, the time-dependent change calculation unit 213 calculates a value from the reference value read from the memory unit 204 that takes into account the time-dependent change in the characteristics of at least one of the light source 170 or image reading sensor 171. That is, the time-dependent change calculation unit 213 calculates a value from the reference value that takes into account the time-dependent change of the reading module 17. For example, in the case of the light source 170, the time-dependent change calculation unit 213 may calculate a value that takes into account the time-dependent change in characteristics by subtracting a value corresponding to the decrease in light intensity over time from the original reference value corresponding to the white evaluation value. Alternatively, the time-dependent change calculation unit 213 may calculate a value that takes into account the time-dependent change in characteristics based on the operating time of the light source 170 or the image reading sensor 171, or the startup time of the image reading device 1. Then, the threshold calculation unit 212 calculates thresholds to be used for the determination process of the cover opening / closing determination unit 203, i.e., for threshold determination of the black evaluation value and the white evaluation value, based on the values ​​calculated by the time-dependent change calculation unit 213.

[0068] Note that the acquisition unit 201, arithmetic processing unit 202b, cover opening / closing determination unit 203, and storage unit 204 shown in Figure 14 are conceptual representations of their functions and are not limited to this configuration. For example, multiple functional units shown as independent functional units in the control device 18b shown in Figure 14 may be configured as a single functional unit. Alternatively, the functions of a single functional unit in the control device 18b shown in Figure 14 may be divided into multiple functions and configured as multiple functional units.

[0069] With the above configuration, it is possible to determine the open / closed state of the cover 11 while taking into account the time-dependent changes in the characteristics of at least one of the light source 170 or the image reading sensor 171, thereby suppressing the occurrence of misjudgments.

[0070] (Variation 3) Next, as a third modification of the second embodiment, we will describe an operation in which, based on the result of the cover opening / closing determination unit 203's determination of the open / closed state of the cover 11, the black evaluation value and white evaluation value when the cover is in the closed state are used as new reference values, and the reference values ​​already stored in the storage unit 204 are updated with these new reference values.

[0071] Figure 15 shows an example of the configuration of the functional block of the control device according to Modification 3 of the second embodiment. The configuration of the functional block of the control device 18c according to this modification will be described with reference to Figure 15.

[0072] As shown in Figure 15, the control device 18c includes an acquisition unit 201, an arithmetic processing unit 202a (an example of a first calculation unit), a cover opening / closing determination unit 203 (determination unit), a storage unit 204, and a selection processing unit 205 (update unit). The operation of the acquisition unit 201, the arithmetic processing unit 202a, and the cover opening / closing determination unit 203 is the same as that of the control device 18a according to the second embodiment described above.

[0073] The selection processing unit 205 acquires the black evaluation value and white evaluation value calculated from the calculation processing unit 202a, as well as the determination result from the cover opening / closing determination unit 203. If the determination result indicates a closed state, the acquired black evaluation value and white evaluation value are used as new reference values, and the unit updates the reference values ​​already stored in the storage unit 204 with these new reference values.

[0074] Note that the acquisition unit 201, arithmetic processing unit 202a, cover opening / closing determination unit 203, storage unit 204, and selection processing unit 205 shown in Figure 15 are conceptual representations of their functions and are not limited to this configuration. For example, multiple functional units shown as independent functional units in the control device 18c shown in Figure 15 may be configured as a single functional unit. Alternatively, the functions of a single functional unit in the control device 18c shown in Figure 15 may be divided into multiple functions and configured as multiple functional units.

[0075] With the above configuration, the latest black and white evaluation values ​​determined to be in the closed state of the image reading device 1 itself can be used as reference values, thereby suppressing misjudgments due to variations between individual machines and misjudgments due to changes over time.

[0076] [Third Embodiment] The image reading device 1 according to the third embodiment will be described, focusing on the differences from the image reading device 1 according to the first embodiment. In this embodiment, the operation of calculating black evaluation values ​​and white evaluation values, respectively, by averaging values ​​in the main scanning direction and sub-scanning direction for each predetermined interval from black data and white data will be described. The overall configuration of the image reading device 1 according to this embodiment, as well as the hardware configuration of the control device and reading module 17, are the same as those described in the first embodiment.

[0077] (Configuration of the control unit's functional blocks) Figure 16 is a diagram showing an example of the configuration of the functional block of the control device according to the third embodiment. The configuration of the functional block of the control device 18d according to this embodiment will be described with reference to Figure 16.

[0078] As shown in Figure 16, the control device 18d includes an acquisition unit 201, an arithmetic processing unit 202c (an example of a first calculation unit), and a cover opening / closing determination unit 203 (determination unit). The operation of the cover opening / closing determination unit 203 is the same as in the first embodiment described above.

[0079] The acquisition unit 201 acquires black data and white data in the main scanning direction and sub-scanning direction from the reading module 17 via the I / F circuit 182.

[0080] The arithmetic processing unit 202c has an averaging processing unit 214.

[0081] The averaging processing unit 214 performs averaging processing on the black data and white data acquired from the acquisition unit 201, calculating the average values ​​in the main scanning direction and sub-scanning direction for each predetermined interval, as the black evaluation value and white evaluation value, respectively. Note that the "predetermined interval" mentioned above may be synonymous with the intervals divided by the calculation processing unit 202 in the first embodiment described above. Alternatively, the averaging processing unit 214 may calculate the average values ​​in at least the main scanning direction for each predetermined interval, from the black data and white data acquired from the acquisition unit 201, as the black evaluation value and white evaluation value, respectively.

[0082] Note that the acquisition unit 201, arithmetic processing unit 202c, and cover opening / closing determination unit 203 shown in Figure 16 are conceptual representations of their functions and are not limited to this configuration. For example, multiple functional units shown as independent functional units in the control device 18d shown in Figure 16 may be configured as a single functional unit. Alternatively, the functions of a single functional unit in the control device 18d shown in Figure 16 may be divided into multiple functions and configured as multiple functional units.

[0083] As described above, by using the black and white evaluation values ​​obtained by averaging the black and white data in the judgment process, it is possible to suppress the problem of the image level becoming low or high in some sections due to the influence of noise and dust, and to suppress the occurrence of misjudgments in the judgment process for determining the open / closed state of the cover 11.

[0084] [Fourth Embodiment] The image reading device 1 according to the fourth embodiment will be described, focusing on the differences from the image reading device 1 according to the first embodiment. In this embodiment, the operation of selecting peak values ​​for each predetermined interval in the main scanning direction from black data and white data, and setting them as black evaluation values ​​and white evaluation values, respectively, will be described. The overall configuration of the image reading device 1 according to this embodiment, as well as the hardware configuration of the control device and reading module 17, are the same as those described in the first embodiment.

[0085] (Configuration of the control unit's functional blocks) Figure 17 shows an example of the configuration of the functional block of the control device according to the fourth embodiment. The configuration of the functional block of the control device 18e according to this embodiment will be described with reference to Figure 17.

[0086] As shown in Figure 17, the control device 18e includes an acquisition unit 201, an arithmetic processing unit 202d (an example of a first calculation unit), and a cover opening / closing determination unit 203 (determination unit). The operation of the acquisition unit 201 and the cover opening / closing determination unit 203 is the same as in the first embodiment described above.

[0087] The arithmetic processing unit 202d includes a peak value selection unit 215.

[0088] The peak value selection unit 215 calculates the peak values ​​for each predetermined interval in the main scanning direction from the black data and white data acquired from the acquisition unit 201, and uses these values ​​as black evaluation values ​​and white evaluation values, respectively. Note that the "predetermined interval" mentioned above may be synonymous with the intervals divided by the calculation processing unit 202 in the first embodiment described above.

[0089] Note that the acquisition unit 201, arithmetic processing unit 202d, and cover opening / closing determination unit 203 shown in Figure 17 are conceptual representations of their functions and are not limited to this configuration. For example, multiple functional units shown as independent functional units in the control device 18e shown in Figure 17 may be configured as a single functional unit. Alternatively, the functions of a single functional unit in the control device 18e shown in Figure 17 may be divided into multiple functions and configured as multiple functional units.

[0090] As described above, by using the peak values ​​for each predetermined interval in the main scanning direction of the black data and white data as the black evaluation value and white evaluation value, respectively, the processing time for the averaging process as in the third embodiment described above is not required, and thus the processing time of the control device 18e can be shortened.

[0091] [Fifth Embodiment] The image reading device 1 according to the fifth embodiment will be described, focusing on the differences from the image reading device 1 according to the first embodiment. In this embodiment, the operation for distinguishing between the open state of the cover 11 and abnormalities of the light source 170, etc., will be described. The overall configuration of the image reading device 1 according to this embodiment, as well as the hardware configuration of the control device and reading module 17, are the same as those described in the first embodiment.

[0092] (Operation of the image reader) Figure 18 is a flowchart showing an example of the operation flow for differentiating between the open cover state and other abnormalities in the image reading device according to the fifth embodiment. Referring to Figure 18, the operation for differentiating between the open cover state of the image reading device 1 according to this embodiment and abnormalities such as the light source 170 (hereinafter referred to as the differentiation operation) will be explained.

[0093] <Step S11> The acquisition unit 201 of the control device 18 acquires black data and white data from the reading module 17 via the I / F circuit 182. Next, the arithmetic processing unit 202 of the control device 18 calculates black evaluation values ​​and white evaluation values, respectively, from the black data and white data acquired by the acquisition unit 201, which are used in the process of determining the open / closed state of the cover 11. Then, the cover open / closed determination unit 203 of the control device 18 uses the black evaluation values ​​and white evaluation values ​​calculated by the arithmetic processing unit 202 to determine the open / closed state of the cover 11. Then, the process proceeds to step S12.

[0094] <Step S12> If the cover opening / closing determination unit 203 determines that the cover 11 is in the open state (step S12: Yes), the process proceeds to step S14. If it determines that the cover is in the closed state (step S12: No), the process proceeds to step S13.

[0095] <Step S13> The image reading device 1 receives the set document and performs a reading operation on the document using the reading module 17. Then, the sorting operation by the image reading device 1 is completed.

[0096] <Step S14> The control device 18 determines whether the number of times the cover 11 has been determined to be in the open state by the cover opening / closing determination unit 203 has reached a predetermined number of times. If the predetermined number of times has been reached (step S14: Yes), the device proceeds to step S16; if the predetermined number of times has not been reached (step S14: No), the device proceeds to step S15.

[0097] <Step S15> The control device 18 notifies the user of the image reading device 1 to close the cover 11. This notification may include, for example, the display of a message prompting the user to close the cover 11 on a display device (not shown) provided by the image reading device 1, or the output of an audio prompting the user to close the cover 11 on a speaker (not shown) provided by the image reading device 1. Then, the process returns to step S11. In this case, the process may also return to step S11 after the notification from the control device 18 is canceled by the user's operation.

[0098] <Step S16> If the number of times the cover 11 has been determined to be in the open state reaches a predetermined number of times, the cover 11 is in the closed state, but at least one of the black evaluation value or white evaluation value is outside the threshold range, and the cover 11 is determined to be another abnormality, such as an abnormality of the light source 170. Examples of such abnormalities include an abnormal state of reduced light intensity due to a malfunction of part or all of the light source 170 of the reading module 17, or an abnormal state of detected value (output value) due to a malfunction of part or all of the image reading sensor 171, or other abnormalities of the reading module 17. In this case, the control device 18 notifies the user of the abnormality. The method described above can also be used for this notification. The troubleshooting operation by the image reading device 1 is then terminated.

[0099] The isolation operation performed by the image reading device 1 as described above makes it possible to determine whether the cover 11 is open or whether some other abnormality has occurred.

[0100] [Sixth Embodiment] The image reading device 1 according to the sixth embodiment will be described, focusing on the differences from the image reading device 1 according to the first embodiment. In this embodiment, the operation of reusing image data used during black adjustment and black correction as black data, and image data used during white adjustment and white correction as white data will be described. The overall configuration of the image reading device 1 according to this embodiment, as well as the hardware configuration of the control device and reading module 17, are the same as those described in the first embodiment.

[0101] (Operation of the image reader) Figure 19 is a flowchart showing an example of the operation flow for reusing black data and white data in the image reading device according to the sixth embodiment. Referring to Figure 19, the operation in the image reading device 1 according to this embodiment in which image data used during black adjustment and black correction is reused as black data, and image data used during white adjustment and white correction is reused as white data will be explained.

[0102] The image reading device 1, with the cover 11 closed and the light source 170 turned off, performs black correction processing using the image data read by the image reading sensor 171 to adjust the image level so that it does not fall below 0 LSB even when noise is taken into consideration when there is no input light. Furthermore, if the image level of the image data is high, the dynamic range becomes narrow and the number of bits cannot be effectively utilized. Therefore, the image reading device 1 performs black correction processing using the image data to subtract the output data when there is no light and correct it to an appropriate value.

[0103] Furthermore, with the cover 11 closed and the light source 170 lit, the image reading device 1 performs a white adjustment process using the image data read from the background plate 11a by the image reading sensor 171 to adjust the image so that the dynamic range can be used as wide as possible, even if the light intensity fluctuates, without causing the image level to overflow. In addition, since reading a document of uniform density does not result in uniform data in the main scanning direction, the image reading device 1 performs a white correction process using the aforementioned image data of the background plate 11a, which is a reference white plate of uniform density, to correct the image of uniform density so that it produces uniform output.

[0104] If the black data and white data described above are acquired separately from the black adjustment, black correction, white adjustment, and white correction processes described above, for use in determining the open / closed state of the cover 11 by the cover opening / closing determination unit 203, the overall processing time of the reading operation by the image reading device 1 will increase, which will have a significant impact on productivity. Therefore, the image reading device 1 according to this embodiment reuses the image data acquired for use in the black adjustment and black correction processes described above as black data, and reuses the image data acquired for use in the white adjustment and white correction processes as white data. The operation of this reuse will be explained below with reference to Figure 19.

[0105] <Step S21> The acquisition unit 201 of the control device 18 acquires image data used for black adjustment processing and black correction processing from the reading module 17 via the I / F circuit 182, and acquires image data used for white adjustment processing and white correction processing. Then, it proceeds to step S22.

[0106] <Step S22> The arithmetic processing unit 202 of the control device 18 reuses the image data acquired by the acquisition unit 201 for black adjustment processing and black correction processing as black data and calculates a black evaluation value used in the process of determining the open / closed state of the cover 11. The arithmetic processing unit 202 also reuses the image data acquired by the acquisition unit 201 for white adjustment processing and white correction processing as white data and calculates a white evaluation value used in the process of determining the open / closed state of the cover 11. Then, the cover open / closed determination unit 203 of the control device 18 uses the black evaluation value and white evaluation value calculated by the arithmetic processing unit 202 to determine the open / closed state of the cover 11. Then, the process proceeds to step S23.

[0107] <Step S23> If the cover opening / closing determination unit 203 determines that the cover 11 is in the open state (step S23: Yes), the process proceeds to step S27. If it determines that the cover is in the closed state (step S23: No), the process proceeds to step S24.

[0108] <Step S24> The control device 18 performs black adjustment and black correction processing using the image data acquired by the acquisition unit 201. The control device 18 also performs white adjustment and white correction processing using the image data acquired by the acquisition unit 201. Then, the process proceeds to step S25.

[0109] <Step S25> The image reading device 1 receives the set document and transports it to the reading position of the reading module 17. Then, it proceeds to step S26.

[0110] <Step S26> The image reading device 1 performs a reading operation on the document using the reading module 17. Then, the operation by the image reading device 1 ends.

[0111] <Step S27> The control device 18 determines whether the number of times the cover opening / closing determination unit 203 has determined that the cover 11 is in the open state has reached a predetermined number of times. If the predetermined number of times has been reached (step S27: Yes), the operation of the image reading device 1 is terminated. If the predetermined number of times has not been reached (step S27: No), the device proceeds to step S28. In addition, if the predetermined number of times has been reached (step S27: Yes), as shown in step S16 of Figure 18 of the fifth embodiment described above, the cover opening / closing determination unit 203 may determine that the cover 11 is in the closed state but at least one of the black evaluation value or white evaluation value has deviated from the threshold range, and may determine this to be an abnormality such as an abnormality of the light source 170.

[0112] <Step S28> The control device 18 notifies the user of the image reading device 1 to close the cover 11. This notification may include, for example, the display of a message prompting the user to close the cover 11 on a display device (not shown) provided by the image reading device 1, or the output of an audio prompting the user to close the cover 11 on a speaker (not shown) provided by the image reading device 1. The process then returns to step S21. In this case, the process may also return to step S21 after the notification from the control device 18 is canceled by the user's operation.

[0113] Furthermore, the operations shown in Figure 19, excluding the document transport and scanning operations, may be performed at a time such as when the power is turned on.

[0114] As described above, by reusing image data acquired for black adjustment and black correction processing as black data, and reusing image data acquired for white adjustment and white correction processing as white data, it becomes unnecessary to separately acquire black data and white data for determining the open / closed state of the cover 11, thereby suppressing an increase in the processing time of the image reading device 1.

[0115] The embodiments of the present invention are as follows. <1> An image reading device for transporting a document and reading an image of the document, A cover portion that can be opened and closed for a predetermined section of the transport path for the aforementioned document, A reading device having a light source and a sensor that detects the reflected light of the light source irradiated onto the document and obtains a reading value, A control device that controls the operation of the reading device, Equipped with, The control device is An acquisition unit that acquires the reading in the main scanning direction obtained by detection by the sensor with the light source turned off as first data, and acquires the reading in the main scanning direction obtained by detection by the sensor with the light source turned on as second data, A first calculation unit calculates a first evaluation value based on data at multiple locations in the main scanning direction in the first data, and calculates a second evaluation value based on data at multiple locations in the main scanning direction in the second data, A determination unit that determines the open / closed state of the cover based on the first evaluation value, determines the open / closed state of the cover based on the second evaluation value, determines that the cover is in an open state if at least one of the determination results based on the first evaluation value and the determination results based on the second evaluation value indicates an open state, and determines that the cover is in a closed state if both indicate a closed state, It is an image reading device equipped with [a specific feature]. <2> The control device is A memory unit that stores a first reference value and a second reference value, A second calculation unit calculates a first threshold for determining the threshold for the first evaluation value based on the first reference value, and calculates a second threshold for determining the threshold for the second evaluation value based on the second reference value. Furthermore, The determination unit determines the open / closed state of the cover by threshold determination using the first threshold value for the first evaluation value, and determines the open / closed state of the cover by threshold determination using the second threshold value for the second evaluation value. <1> This is the image reading device described in [reference]. <3> The storage unit stores, as the first reference value and the second reference value, values ​​unique to each individual image reading device. <2> This is the image reading device described in [reference]. <4> The control device further includes a third calculation unit that calculates values ​​from the first reference value and the second reference value, respectively, that take into account the change over time of the reading device. The second calculation unit calculates the first threshold based on the value calculated by the third calculation unit from the first reference value, and calculates the second threshold based on the value calculated by the third calculation unit from the second reference value. <3> This is the image reading device described in [reference]. <5> The control device further includes an update unit that, when the determination unit determines that the cover is in a closed state, updates the first reference value stored in the storage unit with the first evaluation value calculated by the second calculation unit as the new first reference value, and updates the second reference value stored in the storage unit with the second evaluation value calculated by the second calculation unit as the new second reference value. <2> This is the image reading device described in [reference]. <6> The acquisition unit acquires the readings in at least the main scan lateral direction as the first data and the second data, respectively. The first calculation unit calculates the average value of the data for each predetermined interval in at least the main scanning direction in the first data as the first evaluation value, and calculates the average value of the data for each predetermined interval in at least the main scanning direction in the second data as the second evaluation value. <1> ~ <5> It is an image reading device as described in any one of the items. <7> The first calculation unit calculates the peak values ​​of the data for each predetermined interval in the main scanning direction in the first data as the first evaluation values, and calculates the peak values ​​of the data for each predetermined interval in the main scanning direction in the second data as the second evaluation values. <1> ~ <5> It is an image reading device as described in any one of the items. <8> If the control device determines that the cover is in an open state, it notifies that it is in an open state. The determination unit, After notification by the control device, the open / closed state of the cover is determined. If the number of times the cover portion is determined to be in an open state reaches a predetermined number of times, it is determined that there is an abnormality in the reading device. <1> ~ <7> It is an image reading device as described in any one of the items. <9> The first calculation unit uses the image data used for black adjustment and black correction processing as the first data, and the image data used for white adjustment and white correction processing as the second data. <1> ~ <8> It is an image reading device as described in any one of the items.

[0116] In each of the embodiments and modifications described above, if at least one of the functions of the image reading device 1 is realized by the execution of a program, that program is provided pre-installed in a ROM or the like. In each of the embodiments and modifications described above, the program executed by the image reading device 1 may be configured to be provided as an installable or executable file recorded on a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), a flexible disk (FD), a CD-R (Compact Disk-Recordable), or a DVD (Digital Versatile Disc). In each of the embodiments and modifications described above, the program executed by the image reading device 1 may be configured to be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. In each of the embodiments and modifications described above, the program executed by the image reading device 1 may be configured to be provided or distributed via a network such as the Internet. Furthermore, in each of the embodiments and modifications described above, the program executed by the image reading device 1 is configured as a module that includes at least one of the functional units described above, and in actual hardware, the CPU reads the program from the storage device and executes it, thereby loading and generating the functional units described above onto the main memory. [Explanation of Symbols]

[0117] 1. Image reading device 11 Cover 11a Background board 12 Conveyor paths 13 Loading roller 14 Conveyor rollers 15 Conveyor rollers 15a Pressure Roller 16. Discharge roller 17. Read Module 18, 18a~18e Control devices 170 light source 171 Image reading sensor 172 A / D conversion circuit 180 CPU 181 memory 182 I / F circuit 201 Acquisition Department 202, 202a~202d Arithmetic Processing Unit 203 Cover opening / closing determination unit 204 Storage section 205 Selection Processing Unit 212 Threshold Calculation Unit 213 Time-dependent change calculation unit 214 Averaging Processing Unit 215 Peak Value Selection Section [Prior art documents] [Patent Documents]

[0118] [Patent Document 1] Japanese Patent Publication No. 2010-273028

Claims

1. An image reading device for transporting a document and reading an image of the document, A cover portion that can be opened and closed for a predetermined section of the transport path for the aforementioned document, A reading device having a light source and a sensor that detects the reflected light of the light source irradiated onto the document and obtains a reading value, A control device that controls the operation of the reading device, Equipped with, The control device is An acquisition unit that acquires the reading in the main scanning direction obtained by detection by the sensor with the light source turned off as first data, and acquires the reading in the main scanning direction obtained by detection by the sensor with the light source turned on as second data, A first calculation unit calculates a first evaluation value based on data at multiple locations in the main scanning direction in the first data, and calculates a second evaluation value based on data at multiple locations in the main scanning direction in the second data, A determination unit that determines the open / closed state of the cover based on the first evaluation value, determines the open / closed state of the cover based on the second evaluation value, determines that the cover is in an open state if at least one of the determination results based on the first evaluation value and the determination results based on the second evaluation value indicates an open state, and determines that the cover is in a closed state if both indicate a closed state, Equipped with, The image reading device, wherein the determination unit determines that the cover is in a closed state based on the first evaluation value, and also determines that the cover is in an open state based on the second evaluation value.

2. The control device is A memory unit that stores a first reference value and a second reference value, A second calculation unit calculates a first threshold for determining the threshold for the first evaluation value based on the first reference value, and calculates a second threshold for determining the threshold for the second evaluation value based on the second reference value. Furthermore, The image reading device according to claim 1, wherein the determination unit determines the open / closed state of the cover by threshold determination using the first threshold for the first evaluation value, and determines the open / closed state of the cover by threshold determination using the second threshold for the second evaluation value.

3. The image reading device according to claim 2, wherein the storage unit stores a value unique to each individual image reading device as the first reference value and the second reference value, respectively.

4. The control device further comprises a third calculation unit that calculates values ​​from the first reference value and the second reference value, respectively, that take into account the change over time of the reading device. The image reading device according to claim 3, wherein the second calculation unit calculates the first threshold based on the value calculated by the third calculation unit from the first reference value, and the third calculation unit calculates the second threshold based on the value calculated by the third calculation unit from the second reference value.

5. The image reading device according to claim 2, further comprising an update unit that, when the determination unit determines that the cover is in a closed state, updates the first reference value stored in the storage unit with the first evaluation value calculated by the second calculation unit as a new first reference value, and updates the second reference value stored in the storage unit with the second evaluation value calculated by the second calculation unit as a new second reference value.

6. The acquisition unit acquires the readings in at least the main scanning lateral direction as the first data and the second data, respectively. The image reading device according to any one of claims 1 to 5, wherein the first calculation unit calculates the average value of the data for each predetermined section in at least the main scanning direction in the first data as a first evaluation value, and calculates the average value of the data for each predetermined section in at least the main scanning direction in the second data as a second evaluation value.

7. The image reading device according to any one of claims 1 to 5, wherein the first calculation unit calculates the peak values ​​of the data for each predetermined interval in the main scanning direction in the first data as first evaluation values, and calculates the peak values ​​of the data for each predetermined interval in the main scanning direction in the second data as second evaluation values.

8. If the control device determines that the cover is in an open state, it notifies that it is in an open state. The determination unit, After notification by the control device, the open / closed state of the cover is determined. The image reading device according to any one of claims 1 to 5, wherein if the number of times the cover portion is determined to be in an open state reaches a predetermined number of times, it is determined that there is an abnormality in the reading device.

9. The image reading device according to any one of claims 1 to 5, wherein the first calculation unit uses image data used for black adjustment processing and black correction processing as first data, and uses image data used for white adjustment processing and white correction processing as second data.

Images