Document placement detection device, image reading device, image forming device, method, and program

Abstract

To detect placement of a document of a standard document size.SOLUTION: A document placement detection device comprises: a document platen that transmits light; a plate that is openable and closable with respect to the document platen and covers the document platen in a closed state; an invisible light source that irradiates a placement range in which a document is placed on the document platen with invisible light through the document platen; reading means that receives reflected light from the document and outputs reading data; and placement detection means that detects placement of the document when there is a variation in a reading value of the reading data output by the reading means due to the irradiation with the invisible light.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a document placement detection device, an image reading device, an image forming device, a method, and a program.

Background Art

[0002] Conventionally, in an image reading device, when a user places a document on the reading surface of the image reading device, it is detected that the document is placed, and a document size detection operation is started.

[0003] Patent Document 1 discloses a technique in which when a first angle detection unit turns ON when closing a platen, the size of a document in the sub-scanning direction is determined by a reflection type sensor using invisible light, and when a second angle detection unit turns ON, the size of the document in the main scanning direction is determined according to the reading result of visible light.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, depending on the document size, the detection of the document size is not started until the platen is completely closed. Even after the platen is completely closed, since the light source unit moves to the home position and then the detection of the document size is started, there is a problem that the start of copying and scanning is delayed by that amount.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a document placement detection device, an image reading device, an image forming device, a method, and a program capable of detecting the placement of a document of a standard document size.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, the present invention provides a document placement detection device comprising: a light-transmitting document table; a plate that can be opened and closed relative to the document table and covers the document table when closed; an invisible light source that irradiates invisible light onto the placement area on the document table via the document table; a reading means that receives reflected light from the document and outputs reading data; and the reading data output by the reading means due to the irradiation of the invisible light. from It includes a placement detection means for detecting when a document is placed on it. The aforementioned placement detection means continuously monitors whether there is any change in the reading value of the reading data until the document is placed on the document table, and detects that the document has been placed when there is a change in the reading value of the reading data. It is characterized by the following: [Effects of the Invention]

[0007] According to the present invention, the effect is to be able to detect the placement of a document of a standard size. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of a document placement detection device according to an embodiment. [Figure 2] Figure 2 shows an example of the detection operation in a document placement detection device. [Figure 3] Figure 3 is a flowchart showing an example of the operation of the document placement detection device. [Figure 4] Figure 4 illustrates the detection range of the document placement detection device. [Figure 5] Figure 5 shows an example of the configuration of the document placement detection device according to Modification 1. [Figure 6] Figure 6 is a flowchart showing an example of the operation of the document placement detection device. [Figure 7] Figure 7 shows the difference in power consumption with and without an open / close detection sensor. [Figure 8] Figure 8 shows an example of the detection operation in the document placement detection device of Modification 2. [Figure 9] Figure 9 is a flowchart (part 1) showing an example of the operation of the document placement detection device. [Figure 10]FIG. 10 is a flowchart showing an example of the operation of the document placement detection device (Part 2). [Figure 11] FIG. 11 is a configuration diagram of the background member of the pressure plate according to Modification 3. [Figure 12] FIG. 12 is an explanatory diagram of the background member of the pressure plate. [Figure 13] FIG. 13 is a configuration diagram of the image reading device according to the second embodiment. [Figure 14] FIG. 14 is an operation explanatory diagram of the image reading device according to the second embodiment. [Figure 15] FIG. 15 is an explanatory diagram of the image reading device when a near-infrared light source is used as the invisible light source. [Figure 16] FIG. 16 is a diagram showing an example of the light reception sensitivity characteristics of a CCD using silicon. [Figure 17] FIG. 17 is a diagram showing an example of the configuration of a visible light source and a near-infrared light source. [Figure 18] FIG. 18 is a diagram showing an example of the configuration of the image reading device of Modification 1 of the second embodiment. [Figure 19] FIG. 19 is a diagram showing an example of the configuration of a light source in which a visible light source and a near-infrared light source are integrated. ​​​​​​​​​​​​​​​​​​​​​​

Best Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of a document placement detection device, an image reading device, an image forming device, a method, and a program will be described in detail with reference to the accompanying drawings.

[0010] (Embodiment) The document placement detection device according to the embodiment provides an invisible light source to a reading device that waits on the sub-scanning leading end side before document reading, and detects the placement of a document by constantly monitoring image data by the invisible light source. Hereinafter, the specific configuration of the document placement detection device will be described in detail.

[0011] FIG. 1 is a schematic diagram showing an example of the configuration of a document placement detection device according to the embodiment. As shown in FIG. 1, the document placement detection device 1 includes a transparent document table 11 for placing a document 10, a pressure plate 12 covering the document table 11, an invisible light source 13 for irradiating the document 10 with invisible light, a reading unit 14 for reading the document 10, and a placement detection unit 15 for detecting that a document has been placed.

[0012] Here, the transparent document table 11 is an example of a "document table that transmits light". The pressure plate 12 covering the document table 11 is an example of a "plate that can be opened and closed with respect to the document table and covers the document table in a closed state".

[0013] FIG. 2 is a diagram showing an example of the detection operation in the document placement detection device 1. As shown in FIG. 2, the document placement detection device 1 irradiates invisible light from the invisible light source 13 toward the document table 11, the reading unit 14 receives the reflected light of the invisible light and outputs reading data, and the placement detection unit 15 determines whether the document 10 has been placed based on the reading value of the reading data. The reading data is, as an example, image data. Hereinafter, the reading data will be described as image data.

[0014] When the document 10 is placed in this state, reflection of invisible light occurs from the document 10, and the reading value of the image data fluctuates. The placement detection unit 15 detects that a document has been placed when there is a fluctuation in the reading value of the image data output from the reading unit 14.

[0015] For example, the document detection means 15 detects that a document 10 has been placed on the document tray 11 when the reading value of the image data is equal to or greater than a preset threshold (first threshold).

[0016] Furthermore, the image data readings fluctuate not only when the document 10 is placed on the document glass 11, but also when the pressure plate 12 is closed without the document 10. For this reason, a threshold (second threshold) is also set to prevent the fluctuations that occur when the pressure plate 12 is closed without the document 10 from being mistakenly detected as fluctuations that occur when the document 10 is placed on the document glass 11.

[0017] For example, the difference between the reading of the image data at that time and the reading when the pressure plate 12 is closed without the original document 10 is set as the second threshold. The system is configured to determine that the original document 10 is placed on the device if the reading of the image data satisfies both the condition of being equal to or greater than the first threshold and the condition of being equal to or greater than the second threshold.

[0018] Figure 3 is a flowchart showing an example of the operation of the document placement detection device 1. First, the document placement detection device 1 turns on the invisible light source 13 (step S1) and starts outputting image data by the reading means 14 (step S2).

[0019] Furthermore, the document placement detection device 1 starts monitoring image data fluctuations using the placement detection means 15 (step S3), and determines whether the image data reading value is above a threshold (first threshold) and different from the value when the pressure plate 12 is closed without a document (i.e., above a second threshold) (step S4).

[0020] If the conditions in step S4 are not met (step S4: No), the document placement detection device 1 continues to monitor image data fluctuations from step S3.

[0021] If the conditions of step S4 are met (step S4: Yes), the document placement detection device 1 detects that the document 10 has been placed (step S5).

[0022] Figure 4 is a diagram illustrating the detection range of the document placement detection device 1. It is a top-down view of the document tray 11 and shows the range of each standard size of document 10. The document placement detection device 1 irradiates the detection range M shown in Figure 4 with an invisible light source 13 to monitor image data fluctuations within that range. The detection range M covers the document placement range including all standard sizes and is set to extend across one side of the document tray 11 so that, for example, all standard-sized documents 10 can be detected. As an example, the detection range M is irradiated with an invisible light source waiting on the sub-scanning front end side to monitor image data fluctuations.

[0023] The detection range M should be a range that can detect each standard-format document 10 when it is placed in its respective designated position. For example, it should detect the document 10 whether it is placed horizontally or vertically.

[0024] Therefore, even if the sizes of the original documents 10 are different, it is possible to detect in real time that each original document 10 has been placed on the scanner.

[0025] Furthermore, even if the pressure plate 12 is open during the placement detection operation, the light is invisible, so the user can perform tasks such as placing the document 10 without experiencing glare.

[0026] (Modification 1 of the embodiment) Figure 5 shows an example of the configuration of a document placement detection device according to Modification 1. The document placement detection device 1 shown in Figure 5 has an open / close detection sensor 16 that detects the open / closed state of the pressure plate 12. The document placement detection device performs a placement detection operation when the pressure plate 12 is in the open state, triggered by the detection of the open / closed state by the open / close detection sensor 16.

[0027] Figure 6 is a flowchart showing an example of the operation of the document placement detection device 1 of Modification 1. The document placement detection device 1 detects that the pressure plate 12 has opened using the open / close detection sensor 16 (step S11), and starts the placement detection operation from step S12. The operations from step S12 to step S16 correspond to steps S1 to S5, so their explanation is omitted.

[0028] Figure 7 shows the difference in power consumption with and without the opening / closing detection sensor 16. Figure 7(a) shows the power consumption change when the pressure plate 12 is opened and closed when the opening / closing detection sensor 16 is absent, and Figure 7(b) shows the power consumption change when the pressure plate 12 is opened and closed when the opening / closing detection sensor 16 is present.

[0029] As shown in Figure 7(a), if there is no opening / closing detection sensor 16, there is no trigger for the start and end of the document placement detection operation based on the opening and closing of the pressure plate 12. For this reason, the document placement detection device 1 performs the placement detection operation even when the pressure plate 12 is closed, and therefore consumes power constantly regardless of whether the pressure plate 12 is open or closed.

[0030] However, in most cases, the document placement detection device 1 will not have the document 10 placed on the document tray 11 while the pressure plate 12 is closed. Therefore, the placement detection operation when the pressure plate 12 is closed is wasted. As shown in Figure 7(b), if there is an open / close detection sensor 16, the document placement detection device 1 turns off the placement detection operation when the pressure plate 12 is closed and performs the placement detection operation while the pressure plate 12 is open. In this way, the placement detection operation is turned off while the pressure plate 12 is closed, making it possible to reduce power consumption.

[0031] (Modified example 2 of the embodiment) A document size detection means may be provided to detect the size of the document 10 placed on the document glass 11, and document size detection may be performed.

[0032] Figure 8 shows an example of the detection operation in the document placement detection device 1 of Modification 2. As shown in Figure 8, the document placement detection device 1 has a document size detection means 17. As shown in Figure 8, the placement detection means 15 determines whether a document 10 has been placed based on the reading of the image data, and when it detects that a document has been placed, it transmits a placement detection signal to the document size detection means 17. The document size detection means 17 performs size detection triggered by the placement detection signal.

[0033] Figure 9 is a flowchart showing an example of the operation of the document placement detection device 1 in Modification 2. Note that the operations from steps S21 to S24 correspond to steps S1 to S4, so their explanation is omitted.

[0034] In step S25, when the document placement detection device 1 detects that the document 10 has been placed, it transmits a placement detection signal to the document size detection means 17. The document size detection means 17 performs size detection of the document 10 triggered by the placement detection signal (step S26).

[0035] The size detection in step S26 can be performed, for example, by identifying the main scan size using image data. Figure 10 is a flowchart showing an example of the operation of the document placement detection device 1. As shown in Figure 10, in step S36, the document placement detection device 1 uses the image data to identify the main scan size, triggered by the placement detection signal.

[0036] In this case, the document placement detection device 1 performs placement detection using the image data obtained by the reading means 14 in the placement detection means 15. Placement detection is performed at a standby position where the main scanning size of each standard size can be separated, and after placement detection is complete, the document size detection means 17 performs document size detection using this image data. In this way, document size detection in the main scanning direction can be performed without acquiring image data for document size detection.

[0037] Furthermore, the standby position of the placement detection means 15 may be set to a position that allows for the separation of the main scanning direction for each standard size in the sub-scanning stage.

[0038] This configuration allows for a reduction in the document size detection time. Furthermore, since image data is acquired using an invisible light source, it eliminates glare for the user caused by the size detection process.

[0039] (Modification 3 of the embodiment) The background member, which is made up of the pressure plate 12 and positioned on the back side of the document 10, is not particularly limited, but when the document 10 is white or the like, it is preferable that the background member has the property of reflecting visible light and absorbing invisible light.

[0040] Figures 11 and 12 are explanatory diagrams of the background member of the pressure plate 12 according to Modification 3. As shown in Figure 11, the member of the pressure plate 12 is made of a member 122 that has the property of reflecting visible light and absorbing invisible light.

[0041] Next, Figure 12 illustrates the difference between this method and one using a white background material for the pressure plate 12. In Figure 12(a), a white background material 121 is used for the pressure plate 12. When the pressure plate 12 is fully closed, the back side of the document 10 is covered with the white background material 121. If the document 10 is white, even if invisible light is irradiated, the irradiated light will be reflected from both the document 10 and the background of the pressure plate 12. Therefore, when the pressure plate 12 is fully closed, it becomes difficult to distinguish between the document 10 and the pressure plate 12 in the scanned image.

[0042] In Figure 12(b), the pressure plate 12 uses a background member 122 that has the characteristic of reflecting visible light and absorbing invisible light. When illuminated with visible light, this background member 122 has the characteristic of reflecting light, similar to the background member 121 of a normal pressure plate 12. Therefore, when normal scanning is performed with visible light, it has almost no effect on the scanned image. On the other hand, when invisible light is illuminated, the illuminated light is reflected by the document 10 but absorbed by the background surrounding the document 10. Therefore, even after the pressure plate 12 is completely closed, it is possible to distinguish between the document 10 and the pressure plate 12 in the scanned image, and document placement detection and size detection are possible.

[0043] (Second Embodiment) The document placement detection device 1 may also be applied to the image reading device.

[0044] Figures 13 and 14 are explanatory diagrams of an image reading device according to a second embodiment. The image reading device 2 shown in Figure 13 further includes a document size detection means 17 and a visible light source 18 in addition to the configuration of the document placement detection device 1 (see Figure 5).

[0045] The invisible light source 13 is used to detect the placement and size of the document. The visible light source 18 is used to illuminate the document 10 after the placement and size of the document have been detected, when normal image scanning is performed from the document 10.

[0046] This makes it possible to provide image reading devices that can start copying and scanning quickly.

[0047] (An example of an invisible light source for an image reader) While there are several possible combinations of reading means 14 and invisible light source 13, we will give an example of an invisible light source that can be used when a general semiconductor device is used as the reading means 14. For example, let's assume that a silicon-based CCD (Charge Coupled Device) is used as the reading means 14. In this case, a near-infrared light source can be used as the invisible light source 13. The explanation of why a near-infrared light source can be used is given below.

[0048] Figures 15 and 16 are explanatory diagrams of the image reading device 2 when a near-infrared light source is used as the invisible light source. As shown in Figure 15, the reading means 14 of the image reading device 2 is a silicon-based CCD, and the invisible light source 13 is a near-infrared light source 130.

[0049] Figure 16 shows an example of the light-receiving sensitivity characteristics of a silicon-based CCD. As shown in Figure 16, silicon has light-receiving sensitivity characteristics in the near-infrared region. Therefore, a near-infrared light source 130 can be used.

[0050] While the explanation uses CCDs as an example, it is not limited to them. Other semiconductor devices such as CMOS (Complementary MOS) may also be used.

[0051] Thus, since invisible light sources can be used even with general semiconductor devices, it becomes easier to configure a reading mechanism.

[0052] (Example of a configuration using a visible light source and a near-infrared light source) Figure 17 shows an example of a configuration of visible light sources and near-infrared light sources. As shown in Figure 17, visible light sources 18 and near-infrared light sources 130 are arranged alternately. In the example shown in Figure 17, multiple visible light sources 18 are arranged in a straight line, and near-infrared light sources 130 are placed between consecutive visible light sources 18. Multiple visible light sources 18 and multiple near-infrared light sources 130 are arranged alternately in a straight line.

[0053] As in this example, by providing both a visible light source and a near-infrared light source, a white light source and an invisible light source can be placed on a single substrate, reducing the number of components and the required space.

[0054] (Modification 1 of the second embodiment) In the image reading device 2 of the second embodiment, a visible light source 18 and a near-infrared light source 130 are provided alternately, but the invention is not limited to this configuration.

[0055] Figure 18 shows an example of the configuration of the image reading device 2 in a modified example 1 of the second embodiment. As shown in Figure 18, a light source 19 is provided which integrates a visible light source 18 and a near-infrared light source 130.

[0056] Figure 19 shows an example of the configuration of a light source 19 that integrates a visible light source 18 and a near-infrared light source 130. Figures 19(a) and 19(b) show examples of the configuration of a light source 19 that integrates a visible light source 18 and a near-infrared light source 130, respectively. Both Figure 19(a) and Figure 19(b) include a light guide plate 190, and when the visible light source 18 is turned on, visible light is irradiated onto the document 10 from the surface of the light guide plate 190, and when the near-infrared light source 130 is turned on, near-infrared light is irradiated onto the document 10 from the surface of the light guide plate 190, in an integrated configuration. In this example, near-infrared light is used as an example, but invisible light below the near-infrared range may also be used.

[0057] By integrating the components in this way, space can be saved, and assembly time can also be reduced.

[0058] (Modified operation flow) The operation flow may be modified so that, after the start of monitoring image data fluctuations, the process stops if the fluctuation is not above a threshold.

[0059] Figure 20 is a flowchart showing an example of the operation of the image reading device 2. Step S41 corresponds to step S11 in Figure 6, and steps S42-S47 correspond to steps S21-S26 in Figure 9, so the explanation of these steps is omitted. In this example, the invisible light source is described as a near-infrared light source, but the operation flow is the same.

[0060] In Figure 20, the image reading device 2 stops the placement detection means 15, stops the reading means 14, and turns off the invisible light source, the near-infrared light source 130, in step S48. Then, after stopping for a predetermined time in step S49, the image reading device 2 turns on the near-infrared light source 130 again in step S42, and operates the reading means 14 and the placement detection means 15 to perform placement detection.

[0061] The stop time in step S49 may be set arbitrarily. For example, a motion sensor may be installed in the image reading device 2, and the stop time in step S49 may be set to the period during which this motion sensor is not reacting.

[0062] This configuration makes it possible to reduce power consumption during document placement detection.

[0063] (Automatic reading start operation) In the image reading device 2, after the document size is detected, the user can initiate the reading operation by pressing a button, which starts the document reading operation. The document reading operation may also be set to start automatically.

[0064] Figure 21 is a flowchart showing an example of the automatic reading start operation of the image reading device 2. As shown in Figure 21, the image reading device 2 performs the reading operation in step S50 after the completion of steps S41-S49.

[0065] In this way, the image reading device 2 automatically performs a normal reading operation after the document size detection means 17, eliminating the need for the user to press the read start button, thus shortening the copying and scanning time.

[0066] (Variations of document placement detection operation) Alternatively, image data may be saved when the document placement detection operation starts, and the saved image data may be subtracted from the image data of the document to be detected when determining whether a document has been placed.

[0067] As shown in Figure 22, a data processing unit 20 is provided. The data processing unit 20 saves the image data output from the reading means 14 when the placement detection operation starts, and when determining whether a document has been placed, it subtracts the saved image data from the image data of the object to be detected and outputs the result to the placement detection means 15.

[0068] Figure 23 is a flowchart showing an example of the operation of the image reading device 2. First, the image reading device 2 detects that the pressure plate 12 has opened using the opening / closing detection sensor 16 (step S61), turns on the near-infrared light source 130 (step S62), and starts outputting image data using the reading means 14 (step S63).

[0069] Next, the image reading device 2 determines whether the read value has already been saved in the data processing unit 20 (step S64). If the image reading device 2 determines that the read value has not already been saved in the data processing unit 20 (step S64: No), it saves the read value of the image data in the data processing unit 20 (step S65) and proceeds to step S66.

[0070] Furthermore, if the image reading device 2 determines that the read value has already been saved in the data processing unit 20 (step S64: Yes), it proceeds to step S66.

[0071] Next, the image reading device 2 subtracts the previously stored reading value from the image data output by the reading means 14 (step S66).

[0072] Furthermore, the image reading device 2 starts monitoring image data fluctuations using the placement detection means 15 (step S67), and determines whether the image data reading value is above a threshold (first threshold) and different from the value when the pressure plate 12 is closed without an original document (i.e., above a second threshold) (step S68).

[0073] If the conditions in step S68 are not met (step S68: No), the image reading device 2 stops the placement detection means 15, stops the reading means 14, and turns off the near-infrared light source 130 in step S69. After stopping for a predetermined time in step S70, the near-infrared light source 130 is turned on again in step S62, and the reading means 14 and placement detection means 15 are operated, and the placement detection process from step S62 is repeated.

[0074] If the conditions in step S68 are met (step S68: Yes), the image reading device 2 detects in step S71 that the document 10 has been placed on the document, sends a placement detection signal to the document size detection means 17, which then uses the placement detection signal as a trigger to perform size detection of the document 10 (step S72), and after the size detection is completed, automatically performs a reading operation (step S73).

[0075] This configuration eliminates the effect of ambient light, even when the amount of reflected light is similar to that when the document is placed, thereby improving the document placement detection performance.

[0076] (Examples of application to image forming apparatus) Figure 24 shows an example of the configuration of an image forming apparatus 3 to which the image reading device 2 is applied. In Figure 24, the image forming apparatus 3 is a device commonly referred to as a multifunction device, having at least two functions from among a copy function, a printer function, a scanner function, and a facsimile function.

[0077] The image forming apparatus 3 has an image reading unit 21 corresponding to the image reading device 2, and an image forming unit 31 below it. The image reading unit 21 and the image forming unit 31 are controlled by a built-in control board. For the image forming unit 31, the external cover has been removed to show the internal structure in order to explain the internal configuration.

[0078] The pressure plate 120 corresponds to the pressure plate 12. The pressure plate 120 is fixed to the contact glass 110 (see Figure 25), which corresponds to the document glass 11, so as to be able to open and close. For example, the pressure plate 120 can be opened by the user lifting one side of the pressure plate 120, exposing the surface of the contact glass 110. The pressure plate 120 can also be closed by the user placing the document 10 on the upper surface of the contact glass 110 and lowering one side of the pressure plate 120 back to its original position. In the closed state, the pressure plate 120 presses the document 10 against the upper surface of the contact glass 110.

[0079] The image reading unit 21, as will be described in detail later with reference to Figure 25, has a contact glass 110 on its upper surface on which the document 10 is placed, and reads the document 10 on the contact glass 110. The image reading unit 21 has a reading means 14, an invisible light source 13, and a visible light source 18 inside. In other words, the image reading unit 21 is a scanner that has invisible and visible light sources, an optical system, and semiconductor devices such as an image sensor such as a CCD inside, and irradiates visible or invisible light from the light source and reads the reflected light from the document 10 with the image sensor.

[0080] The image forming unit 31 includes a manual feed roller 304 for manually feeding recording paper and a recording paper supply unit 307 for supplying recording paper. The recording paper supply unit 307 has a mechanism for feeding recording paper from a multi-stage recording paper feed cassette 307a. The supplied recording paper is sent to the secondary transfer belt 312 via a registration roller 308.

[0081] The recording paper being transported on the secondary transfer belt 312 has the toner image on the intermediate transfer belt 313 transferred to it in the transfer section 314.

[0082] The image forming unit 31 also includes an optical writing device 309, a tandem-type image forming unit (Y, M, C, K) 305, an intermediate transfer belt 313, and the secondary transfer belt 312. The image forming process by the image forming unit 305 forms the image written by the optical writing device 309 as a toner image on the intermediate transfer belt 313.

[0083] Specifically, the imaging unit (Y, M, C, K) 305 has four rotatable photoreceptor drums (Y, M, C, K), and each photoreceptor drum is surrounded by an imaging element 306, which includes a charging roller, a developer, a primary transfer roller, a cleaner unit, and a static eliminator. The imaging element 306 functions in each photoreceptor drum, and the image on the photoreceptor drum is transferred onto the intermediate transfer belt 313 by each primary transfer roller.

[0084] The intermediate transfer belt 313 is positioned and stretched by a drive roller and a driven roller in the nip between each photoreceptor drum and each primary transfer roller. The toner image primary transferred to the intermediate transfer belt 313 is then secondary transferred to the recording paper on the secondary transfer belt 312 by the secondary transfer device as the intermediate transfer belt 313 moves. The recording paper is then transported to the fuser device 310 as the secondary transfer belt 312 moves, and the toner image is fixed as a color image on the recording paper. After that, the recording paper is discharged to the output tray outside the machine. In the case of double-sided printing, the front and back sides of the recording paper are reversed by the reversal mechanism 311, and the reversed recording paper is sent onto the secondary transfer belt 312.

[0085] Furthermore, the image forming unit 31 is not limited to forming images by the electrophotographic method described above, but may also form images by an inkjet method.

[0086] Figure 25 shows the configuration of the image reading unit 21. As shown in Figure 25, the image reading unit 21 has a sensor substrate 141 equipped with an image sensor 140, a lens unit 142, a first carriage 143, and a second carriage 144 inside the main body. The first carriage 143 has a light source 130 and a mirror 145. The second carriage 144 has mirrors 146 and 147. The image reading unit 21 also has a contact glass 110 on its upper surface.

[0087] The light source 130 is configured with a visible light source and an invisible light source, either individually or as a single unit. For example, invisible light is light with a wavelength of 380 nm or less, or 750 nm or more. Visible light and invisible light (for example, near-infrared (NIR) light) are selectively irradiated onto the contact glass 110 from the light source 130.

[0088] The image reading unit 21 moves the first carriage 143 and the second carriage 144 from the standby position (home position) in the sub-scanning direction (direction A) during the reading operation. Reflected light from the original document 10 placed on the contact glass 110 and the pressure plate 120 is imaged onto the image sensor 140 via the lens unit 142.

[0089] The image sensor 140 is capable of capturing images in the visible and invisible wavelength ranges. The image sensor 140 is equipped with pixels that convert the amount of incident light into electrical signals. The pixels are arranged, for example, in a matrix, and the electrical signals obtained from each pixel are transferred to a subsequent signal processing unit in a predetermined order at regular intervals.

[0090] Figure 26 shows an example of a control block that controls the image reading unit 21. Figure 26 shows the configuration of the control block that controls image reading.

[0091] The control unit 200 controls the image sensor 140, the image processing unit 204, and the light source drive unit 201. The light source drive unit 201 selectively drives either the invisible light source or the visible light source configured in the light source 130, according to instructions from the control unit 200.

[0092] The pixel unit 202 outputs RGB image data when illuminated by a visible light source from the light source 130, and outputs NIR image data when illuminated by an invisible light source (for example, near-infrared light).

[0093] The signal processing unit 203 processes the data output from the pixel unit 202 and transfers it to the image processing unit 204. The image processing unit 204 performs various image processing operations according to the intended use of the image data. The NIR image data is used for placement detection by the placement detection means 15.

[0094] The processes performed in the embodiments and their respective modifications may be provided by implementing them in an ASIC, or by having a computer execute a program. In the latter case, the program can be pre-installed in a ROM or HDD and provided as a functional unit. In this case, the CPU reads the program and executes it step by step to realize the various functional units. Alternatively, this program may be recorded on a computer-readable recording medium and provided as a computer program product. For example, it may be provided as an installable or executable file recorded on a recording medium such as a flexible disk, CD-R, DVD (Digital Versatile Disk), Blu-ray Disc (registered trademark), or semiconductor memory.

[0095] Furthermore, this program may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Alternatively, the program executed in the embodiments and each of its modifications may be provided or distributed via a network such as the Internet.

[0096] As described above, the embodiments and modifications of the present invention have been explained. However, the embodiments and examples are presented as examples and are not intended to limit the scope of the invention. These novel embodiments and examples can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and examples are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0097] 1 Document placement detection device 10 Document 11 Document table 12 Pressure plate 13 Invisible light source 14 Reading means 15 Placement detection means 17 Document size detection means M Detection range

Prior Art Documents

Patent Documents

[0098] [[ID=三十二]]

Patent Document 1

Claims

1. A light-transmitting document table, A plate that can be opened and closed relative to the document tray and covers the document tray when closed, An invisible light source is provided that illuminates the area on which the document is placed on the document table with invisible light through the document table, A reading means that receives reflected light from the aforementioned document and outputs read data, A placement detection means that detects that a document has been placed on the document from the reading data output by the reading means upon irradiation with the invisible light, and Equipped with, The document placement detection means continuously monitors whether there is a change in the reading value of the scanned data until a document is placed on the document glass, and detects that a document has been placed if there is a change in the reading value of the scanned data. Document placement detection device.

2. The system includes an open / close detection sensor that detects the open / closed state of the aforementioned plate, When the opening / closing detection sensor detects that the plate has been opened, the placement detection means starts monitoring the fluctuations in the reading values ​​of the read data. The document placement detection device according to claim 1.

3. A document size detection means is triggered when the placement detection means detects that the document has been placed on the document, and the document size detection means starts detecting the size of the document. The document placement detection device according to claim 1 or 2, further comprising:

4. The document size detection means detects the document size in the main scanning direction of the document based on the reading data used by the document size detection means described above. The document placement detection device according to claim 3.

5. The plate comprises a material having the characteristic of reflecting visible light and absorbing invisible light. A document placement detection device according to any one of claims 1 to 4.

6. The aforementioned placement detection means is The device detects that a document has been placed on the board when the reading value of the reading data output by the reading means satisfies the condition of the first threshold indicating the fluctuation, and the difference between the reading value of the reading data and the reading value of the reading data when the board is closed without a document satisfies the condition of the second threshold. The document placement detection device according to any one of claims 1 to 5.

7. The aforementioned invisible light source is a near-infrared light source. A document placement detection device according to any one of claims 1 to 6.

8. A document placement detection device according to any one of claims 1 to 7, A visible light source that illuminates the document table with visible light, An image reading device equipped with [a specific feature].

9. Multiple visible light sources and invisible light sources are provided as an integrated unit. The image reading device according to claim 8.

10. During the document placement detection operation, which detects the placement of a document on the document glass, if no document is detected, the document placement detection operation by the document placement detection means, the reading operation by the reading means, and the illumination of the invisible light by the invisible light source are stopped for a predetermined time. The image reading device according to claim 8 or 9.

11. The document size detection means is provided, which starts detecting the size of the document when the placement detection means detects that the document has been placed on it. The reading means performs the visible light reading operation after the document size detection means has detected the document size. The image reading device according to any one of claims 8 to 10.

12. The data processing unit includes a data processing unit that saves the reading value of the reading data at the start of the placement detection operation by the placement detection means, and subtracts the reading value of the reading data at the start from the reading data acquired during the placement detection operation by the placement detection means. The image reading device according to any one of claims 8 to 11.

13. An image reading device according to any one of claims 8 to 12, An image forming unit that forms an image based on the data read from the original document by the image reading device. An image forming apparatus equipped with the following features.

14. A method for detecting that a document has been placed on a document placement detection device, which comprises a light-transmitting document table and a plate that can be opened and closed relative to the document table and covers the document table when closed, The steps include: irradiating the placement area on the document table where the document is placed with invisible light through the document table; The reading means receives reflected light from the original document and outputs the reading data, The process involves continuously monitoring whether there are any changes in the reading values ​​of the reading data output by the reading means due to the irradiation of invisible light until the document is placed on the document table, and detecting that the document has been placed if there is a change in the reading values ​​of the reading data. A method that includes this.

15. A computer in a document placement detection device, which includes a light-transmitting document tray and a plate that can be opened and closed relative to the document tray and covers the document tray when closed, The steps include: irradiating the placement area on the document table where the document is placed with invisible light through the document table; The reading means receives reflected light from the original document and outputs the reading data, The process involves continuously monitoring whether there are any changes in the reading values ​​of the reading data output by the reading means due to the irradiation of invisible light until the document is placed on the document table, and detecting that the document has been placed if there is a change in the reading values ​​of the reading data. A program that executes the command.

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