Reading device and image forming device

Abstract

To provide a reading device that can prevent a reduction in the accuracy of measurement of the dimensions of an object using a reference scale.SOLUTION: A reading device comprises: a correction value calculation unit that calculates a correction value from a read image acquired by an optical sensor and including a reference scale and a plane gauge; and a dimension calculation unit that corrects a measurement image acquired by the optical sensor and including an object and the reference scale by using the correction value, and calculates the dimensions of the object based on the corrected measurement image. The reference scale is provided extending in a main scanning direction orthogonal to a sub scanning direction on the outside of an image acquisition range in which the optical sensor scans the object with the movement of a carriage to acquire an image of the object and on the inside of the maximum movement range in which the carriage can move for the optical sensor to acquire the image of the object. The plane gauge can be placed on a contact glass with a first reference line drawn on its surface directed to the main scanning direction on the inside of the image acquisition range.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a reading device and an image forming device. [Background technology]

[0002] There have been known reading devices that optically read the shape of an object, etc. The reading device has a function of placing the object to be read on a contact glass, reading the shape of the object with an optical sensor mounted on a carriage that moves along the contact glass, and generating image data.

[0003] One example of a conventional reading device is one that has a function of placing a reference scale, which is a hard material with graduations formed at set intervals, on a reading surface, reading an image including an object and the reference scale, and measuring the positional information of the image of the graduations in the read image (see Patent Document 1). This makes it possible to measure the dimensions of the object in the image. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a reading device with the above configuration, there is a possibility that the carriage may move in a tilted state (skew) or the reading characteristics of the optical sensor may change due to wear or deterioration over time of the driving parts or sliding parts, or due to changes in the installation environment of the reading device, etc. As a result, there is a problem that distortion occurs in the image read by the optical sensor, reducing the accuracy of dimensional measurements using the reference scale.

[0005] An object of the present invention is to provide a reading device that can prevent a decrease in accuracy in measuring the dimensions of an object using a reference scale. [Means for solving the problem]

[0006] In order to solve the above technical problems, one aspect of the present invention includes an optical sensor mounted on a carriage that is movable in the sub-scanning direction and that scans an object placed on a contact glass; a reference scale that serves as a reference for calculating the dimensions of the object based on an image acquired by the optical sensor by scanning the object; and a flat gauge that is read by the optical sensor in order to calculate a correction value for correcting the image acquired by the optical sensor; The contact glass is placed The reference scale and the flat gauge generated by reading the optical sensor a correction value calculation unit that calculates the correction value from the read image; The contact glass is placed The object and the reference scale generated by reading the optical sensor a dimension calculation unit that corrects a measurement image using the correction value and calculates dimensions of the object based on the corrected measurement image, wherein the reference scale extends in a main scanning direction perpendicular to the sub-scanning direction outside an image acquisition range in which the optical sensor scans the object by moving the carriage to acquire an image of the object, and inside a maximum movement range in which the carriage can move so that the optical sensor can acquire an image of the object, the object is placed at the same position on the contact glass when calculating the correction value and when calculating the size of the object; The flat gauge is characterized in that it can be placed on the contact glass inside the image acquisition range with a first reference line drawn on the surface facing the main scanning direction. [Effects of the Invention]

[0007] According to the present invention, it is possible to prevent a decrease in accuracy in measuring the dimensions of an object using a reference scale. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the configuration of an MFP as an embodiment of an image forming apparatus according to the present invention. [Figure 2] FIG. 1 is a hardware configuration diagram of a controller serving as a control unit included in an MFP. [Figure 3] FIG. 2 is a block diagram schematically showing the functional configuration of the MFP according to the present embodiment. [Figure 4] FIG. 2 is a diagram showing an outline of an optical system mounted on a carriage. [Figure 5]5A and 5B are diagrams for explaining the cause of carriage skew. [Figure 6] FIG. [Figure 7] FIG. 4 is a diagram showing an example of the arrangement of a reference scale provided in a scanner unit. [Figure 8] FIG. 10 is a diagram illustrating an example of a reading range when the object to be read is a three-dimensional object. [Figure 9] 1A shows a procedure for part measurement processing, FIG. 1B shows a scanned image, and FIG. 1C shows a registered image. [Figure 10] 10 is a flowchart of a correction value calculation process. [Figure 11] FIG. 4 is a diagram showing an example of the operation of the scanner unit. [Figure 12] 10 is a flowchart of a part measurement process. [Figure 13] Dimension measurement process flowchart [Figure 14] 10A and 10B are diagrams showing corrected images including various read objects and a reference scale. [Figure 15] 10 is a flowchart showing another example of part measurement processing. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus and a reading apparatus according to the present invention will be described below with reference to the accompanying drawings.

[0010] [Embodiment of Image Forming Apparatus] 1 is a schematic diagram showing the configuration of an MFP1 as an embodiment of an image forming apparatus according to the present invention. The MFP1 has a scanner unit 100 as an embodiment of a reading device according to the present invention, and an image forming unit 200 that forms an image on a sheet-like medium. However, the present invention can be applied not only to the MFP1 but also to the reading device (scanner unit 100) alone.

[0011] The scanner unit 100 has a contact glass 101, an optical sensor 102, and a carriage 103. The contact glass 101 corresponds to a placement surface on which a read object B, which is an object to be read, is placed. The optical sensor 102 is an image sensor that irradiates light onto the read object B placed on the contact glass 101 and acquires an optical image of the read object B based on the reflected light. The carriage 103 moves in the sub-scanning direction relative to the read object B so that the optical sensor 102 scans the read object B.

[0012] The optical sensors 102 are arranged in a line in a main scanning direction perpendicular to a sub-scanning direction, which is the direction of movement of the carriage 103. The scanner unit 100 is configured to acquire an image of the entire object B to be read by scanning the object B while moving the line, which is the reading position of the optical sensors 102, in the sub-scanning direction.

[0013] The scanner unit 100 also includes an ADF 500 on the contact glass 101 as a medium transport unit that transports a sheet-like object B (medium) to be read.

[0014] The image forming unit 200 has a medium storage section 201 that stores paper P as a sheet-like medium, and an image forming section 202 that forms an image on the paper P. The image forming section 202 can also form an image read by the scanner unit 100 on the paper P.

[0015] [Hardware configuration of the control unit in MFP1] 2 shows an example of the hardware configuration of controller 150 as a control unit included in MFP 1. As shown in FIG. 2, MFP 1 includes a configuration similar to that of a general server or PC (Personal Computer). That is, a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 20, a ROM (Read Only Memory) 30, a HDD (Hard Disk Drive) 40, and an I / F 50 are connected via a bus 90. A display unit 60, an operation unit 70, and a dedicated device 80 are also connected to the I / F 50. The dedicated device 80 includes a scanner unit 100 and an image forming unit 200.

[0016] The CPU 10 is a computing means and controls the overall operation of the MFP 1. The RAM 20 is a volatile storage medium that allows high-speed reading and writing of information and is used as a work area when the CPU 10 processes information. The ROM 30 is a read-only nonvolatile storage medium that stores programs such as firmware. The HDD 40 is a nonvolatile storage medium that allows reading and writing of information and stores the OS (Operating System), various control programs such as an applied voltage control program, application programs, etc.

[0017] The I / F 50 connects and controls the bus 90 with various hardware, networks, etc. The display unit 60 is a visual user interface that allows the user to check the status of the MFP 1, and is realized by a display device such as an LCD (Liquid Crystal Display). The operation unit 70 is a user interface that allows the user to input information to the MFP 1.

[0018] In such a hardware configuration, a software control unit is configured by reading a program stored in a storage medium such as ROM 30, HDD 40, or an optical disk (not shown) into RAM 20, and CPU 10 performing calculations in accordance with the program loaded into RAM 20. A functional block that realizes the functions of the MFP1 according to this embodiment is configured by combining the software control unit configured in this way with hardware.

[0019] [MFP1 functional blocks] Next, the functional configuration of the MFP1 according to this embodiment will be described with reference to Fig. 3. Fig. 3 is a block diagram that schematically shows the functional configuration of the MFP1 according to this embodiment. In Fig. 3, electrical connections are indicated by solid arrows, and the flow of transfer paper or document stacks is indicated by dashed arrows.

[0020] 3, the MFP 1 according to this embodiment includes a controller 150, a paper feed table 203, a print engine 300, a print paper output tray 400, an ADF (Auto Document Feeder) 500, a scanner engine 600, a scan paper output tray 700, a display panel 800, and a network I / F 900. The controller 150 also includes a main control unit 151, an engine control unit 152, an image processing unit 153, an operation display control unit 154, and an input / output control unit 155.

[0021] The paper feed table 203 feeds transfer paper to the print engine 300, which is an image forming unit. The print engine 300 is an image forming unit that forms an image by executing image formation output on the transfer paper conveyed from the paper feed table 203. A specific example of the print engine 300 according to this embodiment is an electrophotographic image forming mechanism. The transfer paper on which the image has been formed by the print engine 300 is discharged to a print paper discharge tray 400. The print engine 300 is realized by a dedicated device 80 shown in FIG. 2.

[0022] The ADF 500 automatically transports the object B to a position where it can be read by the scanner engine 600, which executes the main processing in the scanner unit 100. The scanner engine 600 is a document reading unit that includes a photoelectric conversion element that converts optical information into an electrical signal, and optically scans and reads a document that has been automatically transported by the ADF 500 or a document set on a document platen glass (not shown) to generate image information. The document that has been automatically transported by the ADF 500 and read by the scanner engine 600 is discharged onto a scan paper output tray 700. The ADF 500 and the scanner engine 600 are realized by a dedicated device 80 shown in FIG. 2.

[0023] Display panel 800 is an output interface that visually displays the status of MFP 1, and also serves as an input interface as a touch panel when a user directly operates MFP 1 or inputs information to MFP 1. In other words, display panel 800 has a function of displaying images for receiving operations by the user. Display panel 800 is realized by display unit 60 and operation unit 70 shown in FIG. 2.

[0024] The network I / F 900 is an interface that enables the MFP 1 to communicate with other devices such as an administrator terminal or a PC (Personal Computer) via a network, and interfaces such as Ethernet (registered trademark), USB (Universal Serial Bus) interface, Bluetooth (registered trademark), Wi-Fi (Wireless Fidelity) (registered trademark), and FeliCa (registered trademark) are used. In this manner, the MFP 1 according to this embodiment receives various control commands, such as image data for a print request and a print request, from a terminal connected via the network I / F 900. The network I / F 900 is realized by the I / F 50 shown in FIG. 2.

[0025] The controller 150 is configured by a combination of software and hardware. Specifically, the controller 150 is configured by a software control unit configured by loading control programs such as firmware stored in a nonvolatile storage medium such as the ROM 30 or the HDD 40 into the RAM 20 and having the CPU 10 perform calculations in accordance with these programs, and hardware such as an integrated circuit. The controller 150 functions as a control unit that controls the entire MFP 1. Therefore, in this embodiment, the controller 150 functions as an applied voltage control device.

[0026] The main control unit 151 controls each unit included in the controller 150 and issues commands to each unit of the controller 150. The main control unit 151 also controls the input / output control unit 155 and accesses other devices via the network I / F 900 and the network. The engine control unit 152 controls or drives the drive units such as the print engine 300 and the scanner engine 600.

[0027] Image processing unit 153 generates drawing information as output information based on image information described in PDL (Page Description Language) or the like, for example, document data or image data included in an input print job, under the control of main control unit 151. This drawing information is information such as CMYK bitmap data, and is information used by print engine 300, which is an image forming unit, to draw an image to be formed in an image forming operation.

[0028] Furthermore, image processing unit 153 processes the imaging data input from scanner engine 600 and generates image data. This image data is information that is stored in MFP1 as a result of the scanner operation or is transmitted to other devices via network I / F 900 and the network. Note that MFP1 according to this embodiment can also receive drawing information directly instead of image information and perform image formation and output based on the directly input drawing information.

[0029] The operation display control unit 154 displays information on the display panel 800 or notifies the main control unit 151 of information input via the display panel 800. The input / output control unit 155 inputs signals and commands input via the network I / F 900 and the network to the main control unit 151.

[0030] [Scanner Unit 100 Details] Next, the detailed configuration of the scanner unit 100 will be described. Fig. 4 is a diagram showing an overview of the optical system mounted on the carriage 103. As shown in Fig. 4, light from a light source mounted on the carriage 103 is reflected by the object B to be read, and the reflected light enters the reduction optical system via optical path h and is reflected by a first mirror 1031. Note that the light source is not shown in Fig. 3.

[0031] The light reflected by the first mirror 1031 is reflected by the second mirror 1032, the third mirror 1033, the fourth mirror 1034, the fifth mirror 1035, and the sixth mirror 1036, and passes through the lens 1037 to enter the optical sensor 102. The optical sensor 102 is, for example, a CCD sensor.

[0032] Based on the light detected by the optical sensor 102, the image of the object B to be read is converted into an electrical signal and subjected to predetermined processing in the controller 150. In this way, image data of the object B to be read is generated.

[0033] Fig. 5 is a diagram illustrating one cause of skew of the carriage 103. As shown in Fig. 5, the scanner unit 100 further includes a drive mechanism 104 that moves the carriage 103 in the sub-scanning direction. The carriage 103 is configured to be movable in the sub-scanning direction by the drive mechanism 104 while extending in the main scanning direction.

[0034] 5(a), the drive mechanism 104 is composed of a motor 1041, a drive pulley 1042, a driven pulley 1043, a timing belt 1044, and a guide rod 1045. The drive pulley 1042 and the driven pulley 1043 are arranged spaced apart in the sub-scanning direction. The timing belt 1044 is stretched over the drive pulley 1042 and the driven pulley 1043 and connected to the carriage 103. The guide rod 1045 extends in the sub-scanning direction and guides the movement of the carriage 103.

[0035] When the driving force of the motor 1041 is transmitted to the driving pulley 1042, the driving pulley 1042 rotates, and the timing belt 1044 rotates between the driving pulley 1042 and the driven pulley 1043. As a result, the carriage 103 is guided by the guide rod 1045 and moves back and forth in the sub-scanning direction.

[0036] As shown in FIG. 5(b), in order for the carriage 103 to move along the guide rod 1045, a gap (backlash) is required between the carriage 103 and the guide rod 1045. Furthermore, the timing belt 1044 and the guide rod 1045 are disposed so as to be spaced apart in the main scanning direction. The gap (backlash) between the carriage 103 and the guide rod 1045 occurs in the main scanning direction at a fitting portion between the outer circumferential surface of the guide rod 1045 and the carriage 103. As a result, as shown in FIG. 5(c), the carriage 103, which is moved by the driving force transmitted from the timing belt 1044, may move at an angle with the position of the guide rod 1045 as a base point.

[0037] That is, the position where force is applied to carriage 103 to move carriage 103 in the sub-scanning direction is near one end of carriage 103 in the main scanning direction. When timing belt 1044, which is fixed here, rotates, the engagement portion between carriage 103 and guide rod 1045 becomes a fulcrum, and the end of carriage 103 tries to rotate in the rotation direction of timing belt 1044. Due to this action, when carriage 103 moves in the sub-scanning direction, it becomes inclined from an orientation perpendicular to guide rod 1045, so when reading processing is performed on read object B, reading is performed while carriage 103 moves in the sub-scanning direction while maintaining its orientation inclined from its normal orientation in the main scanning direction.

[0038] 6 is a plan view of the scanner unit 100, showing the contact glass 101 as viewed from the placement surface side on which the object to be read B is placed. The rear surface of the contact glass 101 illustrated in FIG. 6 (the surface on the depth side of the paper) corresponds to the reading surface of the contact glass 101.

[0039] As shown in Fig. 6, an original size reference 1011 is shown on the placement surface side of the contact glass 101 as a reference position when placing a planar (sheet-like) read object B. Fig. 6 illustrates an example of a standby state before the scanner unit 100 starts a reading operation, so the carriage 103 is waiting at a carriage home position 1012. The carriage home position 1012 corresponds to the standby position of the carriage 103 before starting scanning.

[0040] The scanner unit 100 is preset with a flat medium maximum size reading area 1013, which is the maximum range of the image acquisition range in which the object B to be read is scanned to acquire an image, and a carriage maximum reading area 1014, which is the maximum movement range in which the optical sensor 102 can be scanned by the carriage 103. In other words, the area surrounded by the end position of the maximum range in which the carriage 103 scans and the carriage home position 1012, which is the opposite end thereof, corresponds to the carriage maximum reading area 1014.

[0041] FIG. 6 illustrates, by a shaded area, a maximum size reading area 1013 for a flat medium when the reading object B is an A3 size paper P.

[0042] Fig. 7 is a diagram showing an example of the arrangement of the reference scale 105 provided in the scanner unit 100. As shown in Fig. 7, the reference scale 105 includes a main scanning direction scale 1051 and a sub-scanning direction scale 1052. As shown in Fig. 7, the main scanning direction scale 1051 extends in the main scanning direction outside the end in the sub-scanning direction of the largest document size that can be read on the contact glass 101. The sub-scanning direction scale 1052 extends in the sub-scanning direction outside the end in the main scanning direction of the largest document size that can be read on the contact glass 101.

[0043] The main scanning direction scale 1051 and the sub-scanning direction scale 1052 are both arranged at positions that correspond to the outside of the maximum planar medium size reading area 1013 and the inside of the carriage maximum reading area 1014. In FIG. 7, the reference scale 105 is a component that arranges "scale lines" that function as a dimensional measurement standard on the reading surface of the contact glass 101. The main scanning direction scale 1051 has scale lines that extend in the sub-scanning direction and are drawn at positions spaced apart in the main scanning direction. The sub-scanning direction scale 1052 has scale lines that extend in the main scanning direction and are drawn at positions spaced apart in the sub-scanning direction.

[0044] The reference scale 105 may be arranged on either the lower surface (carriage 103 side) of the contact glass 101 or the upper surface (surface on which the object to be read B is placed).

[0045] Note that arranging the reference scale 105 on the upper surface (the surface on which the read object B is placed) improves the accuracy of calibration of the reading by the optical sensor 102. Furthermore, since the reference scale 105 is used to calibrate the optical sensor 102, it is essential to provide scale lines on the lower surface (the carriage 103 side). In other words, the reference scale 105 may be arranged on both the upper and lower surfaces. Arranging the reference scale 105 on both surfaces allows the user to visually recognize the position of the reference scale 105, and also allows the optical sensor 102, which faces upward from the lower surface side of the contact glass 101, to simultaneously acquire images of the reference scale 105 and the read object B.

[0046] It is desirable that the surface of the reference scale 105 arranged on the carriage 103 side have a different color for displaying the scale lines from the color of the area where the scale lines are formed, so as not to reflect light from the light source mounted on the carriage 103. For example, the lines that display the scale lines can be made white by polishing the stainless steel, and the contrast of the lines in the image can be enhanced to make them easier to identify.

[0047] Even if the reference scale 105 is made of SUS and the graduations are formed in black, no problem occurs in the process of acquiring an image of the object B to be read at the same time.

[0048] Fig. 8 is a diagram illustrating the reading range when the object to be read B is a three-dimensional object. As shown in Fig. 8, the part measurement range 1015 is set at a position different from the flat medium maximum size reading area 1013, which is the reading range when the object to be read B is a planar object. The range of the part measurement range 1015 in the sub-scanning direction is set such that the vicinity of the turning point in the movement of the carriage 103 is set as the reference position for placement. In addition, the range in the main scanning direction is set so as to be distributed relative to the center of the optical path, and therefore the central position in the main scanning direction is set as the reference position for placement.

[0049] It should be noted that there is a tendency for positional deviation to be greater in the movement direction of the carriage 103 (sub-scanning direction) than in the optical direction (main scanning direction) in which the optical sensor 102 mounted on the carriage 103 optically reads the object B to be read. Therefore, in order to further improve measurement accuracy, the intervals between the graduation lines of the sub-scanning direction scale 1052 are formed narrower than the intervals between the graduation lines of the main scanning direction scale 1051. In other words, the sub-scanning direction scale 1052 is a finer reference scale 105 than the main scanning direction scale 1051.

[0050] [Correction Value Calculation Process by Scanner Unit 100] Next, the correction value calculation process by the scanner unit 100 will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a diagram showing (a) the procedure of the part measurement process, (b) a scanned image, and (c) a registered image. Fig. 10 is a flowchart showing an example of the correction value calculation process that can be executed by the scanner unit 100.

[0051] First, the user opens the pressure plate (S1001) to place the object to be read B on the placement surface of the contact glass 101. The pressure plate is a configuration including the ADF 104, and is an example of a plate-like member that covers the contact glass 101 to hold a flat object placed on the contact glass 101.

[0052] Next, the user places the flat gauge 106 on the placement surface of the contact glass 101 (S1002). As shown in Fig. 9(a), the flat gauge 106 is a sheet-shaped member (e.g., paper or flat plate) on which a plurality of first reference lines 1061 and a plurality of second reference lines 1062 are drawn.

[0053] The multiple first reference lines 1061 and the multiple second reference lines 1062 are arranged at positions spaced apart from each other. The first reference lines 1061 and the multiple second reference lines 1062 extend in directions perpendicular to each other. That is, the multiple first reference lines 1061 and the multiple second reference lines 1062 are arranged in a grid pattern on the flat gauge 106. The flat gauge 106 is placed on the flat medium maximum size reading area 1013 with the first reference line 1061 facing the main scanning direction and the second reference line 1062 facing the sub-scanning direction.

[0054] Next, the user presses the "correction value calculation button" provided on the operation unit 70 to start the reading process (S1003). When the reading process starts, first, the carriage 103 operates (S1004), and the optical sensor 102 scans the object B to be read as the carriage 103 moves.

[0055] The correction value calculation unit scans the flat gauge 106 and the reference scale 105 while moving the carriage 103 to the carriage maximum reading area 1014, acquires a read image including the flat gauge 106 and the reference scale 105, and stores the image in a storage area (S1005). Here, as shown in FIG. 5(c), if the carriage 103 moves in a skewed state, the read image acquired in step S1005 will be distorted as shown in FIG. 9(b).

[0056] On the other hand, as shown in FIG. 9(c), a registered image is stored in the HDD 40 (memory). The registered image is an image including a reference scale 105 and a flat gauge 106 in which a first reference line 1061 faces the main scanning direction and a second reference line 1062 faces the sub-scanning direction. In other words, the registered image corresponds to an undistorted image obtained by reading the state shown in FIG. 9(a). The registered image is created in advance and stored in the HDD 40.

[0057] Next, the correction value calculation unit calculates a correction value by comparing the read image shown in Fig. 9(b) with the registered image shown in Fig. 9(c) (S1006). The correction value is a numerical value indicating the amount of movement of each pixel to make the read image acquired by the optical sensor 102 closer to (more specifically, to match) the registered image stored in the HDD 40.

[0058] More specifically, for each of the multiple pixels constituting the scanned image, the correction value calculation unit identifies a corresponding pixel (a pixel indicating the same portion) in the registered image. Next, the correction value calculation unit calculates the amount of shift (=movement amount) of each corresponding pixel in the scanned image and the registered image as a correction value. For example, in FIGS. 9(b) and 9(c), the correction values ​​of pixels P1 and P2 are values ​​that move pixels P1 and P2 in the direction of the arrows by the length of the arrows. On the other hand, pixel P3 in FIGS. 9(b) and 9(c) matches, so the correction value of pixel P3 is zero. In other words, the correction value may differ for each pixel. Then, the correction value calculation unit stores the calculated correction value in HDD 40 (S1007).

[0059] The correction value calculation unit may calculate a correction value for each pixel in the scanned image, or may calculate a correction value for each group of adjacent pixels (i.e., pixel block), or may calculate a correction value for each row of pixels adjacent in the sub-scanning direction. Since the image processing method used by the correction value calculation unit is well known, detailed description thereof will be omitted.

[0060] 9 and 10 (i.e., the correction value calculation unit) is realized by calculation processing that can be executed by the main control unit 151 and the image processing unit 153. In the above processing, a process is executed in the image processing unit 153 to identify the respective image portions of the read image including the reference scale 105 and the flat gauge 106. The result of this processing is passed to the main control unit 151, and the main control unit 151 executes a process to calculate the correction value.

[0061] [Part measurement processing using the scanner unit 100] Next, the part measurement process by the scanner unit 100 will be described with reference to Fig. 11. Fig. 11(a) shows an example of an image acquired by performing a reading process on a planar object B to be read, which is an A3-sized piece of paper P. In this case, an image is acquired within an area of ​​420 mm x 297 mm.

[0062] 11(b) shows an example in which the object to be read B is a three-dimensional object, and an image is acquired by scanning within the movable range of the carriage 103. In this case, for example, images of the object to be read B and the reference scale 105 are acquired simultaneously within an area of ​​440 mm x 305 mm.

[0063] Then, the image portion of the object B to be read contained in the acquired image is compared with the image portion of the reference scale 105, and a process of measuring the dimensions of the object B to be read is carried out.

[0064] [First example of part measurement processing flow] Fig. 12 is a flowchart showing an example of a part measurement process that can be executed by the scanner unit 100. The flowchart in Fig. 12 illustrates an example in which the object to be read B is a three-dimensional object.

[0065] First, the user opens the pressure plate (S1201) in order to place the object B to be read on the placement surface of the contact glass 101. Next, the user places the object B to be read on the placement surface of the contact glass 101 (S1202).

[0066] Next, the user presses the "part measurement button" provided on the operation unit 70 to start the reading process (S1203). When the reading process starts, first, the carriage 103 operates (S1204), and as the carriage 103 moves, the optical sensor 102 scans the object B to be read.

[0067] The dimension calculation unit scans the object B to be read while moving the carriage 103 to the carriage maximum reading area 1014, acquires a measurement image including the object B to be read and the reference scale 105, and stores it in a storage area (S1205).

[0068] Next, the dimension calculation unit executes the dimension measurement process shown in Fig. 13 (S1206). The dimension measurement process is a process of correcting the acquired measurement image, identifying the portion of the reference scale 105 and the portion of the object to be read B included in the corrected measurement image, and measuring the dimension of the object to be read B by comparing these identified images. Fig. 13 is a flowchart showing an example of the dimension measurement process executed in step S1206.

[0069] First, the dimension calculation unit corrects the measurement image acquired in step S1205 with the correction value calculated in step S1006 (S1301). More specifically, the dimension calculation unit moves each pixel constituting the measurement image by the corresponding correction value. This generates a corrected image in which the distortion of the measurement image has been corrected.

[0070] Next, the dimension calculation unit extracts the scale lines of the reference scale 105 and the outline of the object B to be read from the corrected image (S1302). A method for extracting a specific portion from the corrected image (for example, edge detection) is already well known, so a detailed description thereof will be omitted.

[0071] Next, the dimension calculation unit determines the extracted dimension of the object B to be read based on the interval between the scale lines of the extracted reference scale 105 (S1303). More specifically, the dimension calculation unit determines the dimension by multiplying the number of scale lines facing the outline of the object B to be read, whose dimension is to be determined, by the interval (μm) between the scale lines determined in advance. Furthermore, when the end position of the object B to be read is located between adjacent scale lines, the dimension calculation unit proportionally allocates the number of pixels between the scale lines. The specific process for determining the dimension is already well known, as described in Patent Document 1, and therefore a detailed description thereof will be omitted.

[0072] Finally, returning to FIG. 12, the dimension measurement unit displays the results of the measurement process on the display unit 60 (S1207), and the process of reading the three-dimensional object ends.

[0073] A method for identifying various dimensions of the objects B1, B2, and B3 to be read in step S1303 will be described with reference to Fig. 14. Fig. 14 is a diagram showing a corrected image including various objects B1, B2, and B3 to be read and a reference scale 105.

[0074] 14(a), when specifying a dimension D1 of a rectangular read object B1, the dimension calculation unit counts the number of graduations on the main scanning direction scale 1051 between vertices a1 and a2. When specifying a dimension D2 of the read object B1, the dimension calculation unit counts the number of graduations on the sub scanning direction scale 1052 between vertices a2 and a3.

[0075] 14(b), when determining the dimension D3 of the rectangular read object B2, the dimension calculation unit determines the dimension D4 of the vertices a4 and a5 in the main scanning direction and the dimension D5 of the vertices a4 and a5 in the sub-scanning direction. The method for determining the dimensions D4 and D5 is the same as in FIG. 14(a). Then, the dimension calculation unit determines the dimension D3 from the determined dimensions D4 and D5 using Pythagoras' theorem.

[0076] Furthermore, as shown in Fig. 14(c), when determining the diameter D6 of a circular reading object B3, the dimension calculation unit determines the maximum dimensions of the reading object B3 in each of the main scanning direction and the sub-scanning direction by the method of Fig. 14(a). Then, the dimension calculation unit determines the average value of the maximum dimension in the main scanning direction and the maximum dimension in the sub-scanning direction as the diameter D6.

[0077] [Second example of part measurement processing flow] Fig. 15 is a flowchart showing another example of part measurement processing that can be executed in scanner unit 100. The flowchart in Fig. 15 illustrates a case where object B to be read is a three-dimensional object, and illustrates processing in which the user arbitrarily designates measurement locations.

[0078] As in the first example already described, first, the user opens the pressure plate (S1501) to place the object B to be read on the placement surface of the contact glass 101, and places the object B to be read on the placement surface of the contact glass 101 (S1502). After that, the user presses the "preview button" provided on the operation unit 70 to start the preview process (S1503).

[0079] The preview process is a process of acquiring only an image of the object B to be read and displaying a preview of the acquired image on the display unit 60. That is, first, the dimension measurement unit operates the carriage 103 (S1504), and scans the object B to be read by the optical sensor 102 as the carriage 103 moves. The scanner unit 100 scans the object B to be read while moving the carriage 103 in an area (part measurement range 1015) set for reading the object B, and simultaneously acquires an image of the object B to be read (S1505), and stores the image in a storage area.

[0080] Next, the dimension measurement unit displays the image saved in the storage area as a preview image on the display unit 60 (S1506). Then, the user performs an operation to specify measurement points on the image displayed on the display unit 60 via the operation unit 70 (S1507). After specifying the measurement points, the user presses a "part measurement button" provided on the operation unit 70 to start the reading process (S1508).

[0081] When the reading process is started, the scanner unit 100 moves the carriage 103 and causes the optical sensor 102 to scan the object B to be read, and executes scanning of the object B to be read while moving the carriage 103 to the carriage maximum reading area 1014. As a result, a measurement image can be acquired that includes an image of the object B to be read in the range specified as the measurement location and an image of the reference scale 105, and the dimension measurement unit stores this in a memory area (S1509).

[0082] Next, the dimension measurement unit executes the dimension measurement process shown in Fig. 13 (S1510). Finally, the dimension measurement unit displays the results of the measurement process on the display unit 60 (S1511), and ends the process of reading the three-dimensional object.

[0083] 12, 13, and 15 (i.e., the dimension calculation unit) is realized by calculation processing that can be executed by the main control unit 151 and the image processing unit 153. In the above processing, a process is executed in the image processing unit 153 to identify the image portions of the object to be read B and the reference scale 105, which are simultaneously acquired images. The result of this process is passed to the main control unit 151, which then executes a dimension calculation process.

[0084] According to the above embodiment, by correcting the measurement image using the correction value calculated using the flat gauge 106, it is possible to prevent a decrease in the accuracy of the dimensional measurement of the object to be read B using the reference scale 105.

[0085] Furthermore, according to the above embodiment, by adding a first reference line 1061 and a second reference line 1062 that are orthogonal to each other to the flat gauge 106, it is possible to simultaneously calculate correction values ​​in the main scanning direction and the sub-scanning direction. As a result, it is possible to correct the measurement image more accurately. However, if the carriage 103 is skewed as shown in FIG. 5, it is sufficient to calculate the correction value in the sub-scanning direction only, so it is sufficient that at least the first reference line 1061 is drawn on the flat gauge 106.

[0086] 13, an example has been described in which the entire measurement image is corrected, and then the scale lines of the reference scale 105 and the outline of the object to be read B are extracted from the corrected image, but the processing procedure is not limited to this. As another example, the dimension calculation unit may extract the reference scale 105 and the object to be read B from the measurement image, and then correct only the extracted parts using the correction value. This allows only the necessary parts in the measurement image to be selectively corrected, thereby improving the processing speed.

[0087] In the above embodiment, an example has been described in which the correction value calculation process shown in Fig. 10 is executed when the user presses the "correction value calculation button" provided on the operation unit 70. This allows the user to explicitly instruct the execution of the correction value calculation process when the user changes the installation environment of the MFP 1. However, the execution timing of the correction value calculation process is not limited to the above example.

[0088] As another example, controller 150 may execute the correction value calculation process shown in Fig. 10 in response to MFP 1 (more specifically, scanner unit 100) having operated for a predetermined operating time, and update the correction values ​​stored in HDD 40. This allows appropriate correction values ​​to be calculated in accordance with wear and deterioration over time of driving parts or sliding parts.

[0089] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical gist thereof. The present invention covers all technical matters included in the technical ideas described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various modifications from the disclosed contents. Such modifications are also included in the technical scope described in the claims. [Explanation of symbols]

[0090] 1: MFP 10: CPU 20:RAM 30:ROM 40: HDD 50: Interface 60:Display section 70:Operation unit 80: Dedicated device 90: Bus 100: Scanner unit 101: Contact glass 102: Optical sensor 103: Carriage 104: Drive mechanism 105: Reference scale 106: Flat gauge 150: Controller 151: Main control unit 152: Engine control unit 153: Image processing unit 154: Operation display control unit 155: Input / output control unit 200: Image forming unit 201: Media storage unit 202: Image forming unit 203: Paper feed table 300: Print engine 400: Print output tray 600: Scanner engine 700: Scan output tray 800: Display panel 900: Network I / F 1012: Carriage home position 1013: Maximum size reading area for flat media 1014: Carriage maximum reading area 1015: Parts measurement range 1031: First mirror 1032: Second mirror 1033: Third Mirror 1034: Fourth Mirror 1035: Fifth Mirror 1036: Sixth Mirror 1037: Lens 1041: Motor 1042: Drive pulley 1043: Driven pulley 1044: Timing belt 1045: Guide rod 1051: Main scanning scale 1052: Sub-scanning scale 1061 :First reference line 1062:Second reference line [Prior art documents] [Patent documents]

[0091] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-151548

Claims

1. an optical sensor mounted on a carriage movable in a sub-scanning direction and configured to scan an object placed on the contact glass; a reference scale that serves as a reference for calculating the dimensions of the object based on an image acquired by scanning the object with the optical sensor; a flat gauge that is read by the optical sensor to calculate a correction value for correcting the image acquired by the optical sensor; a correction value calculation unit that calculates the correction value from a read image generated by reading the reference scale and the flat gauge placed on the contact glass with the optical sensor; a dimension calculation unit that uses the correction value to correct a measurement image generated by reading the object placed on the contact glass and the reference scale with the optical sensor, and calculates the dimensions of the object based on the corrected measurement image, the reference scale extends in a main scanning direction perpendicular to the sub-scanning direction, outside an image acquisition range in which the optical sensor scans the object and acquires an image of the object by moving the carriage, and inside a maximum movement range in which the carriage can move in order for the optical sensor to acquire an image of the object, and is placed at the same position on the contact glass when calculating the correction value and when calculating the dimensions of the object; The reading device is characterized in that the flat gauge can be placed on the contact glass inside the image acquisition range with a first reference line drawn on the surface facing the main scanning direction.

2. 2. The reading device according to claim 1, wherein the reference scale has graduations drawn at positions spaced apart in the main scanning direction, the graduations extending in the sub-scanning direction.

3. 3. The reading device according to claim 2, wherein the reference scale further extends in the sub-scanning direction, and has graduations drawn at positions spaced apart in the sub-scanning direction, each of the graduations extending in the main scanning direction.

4. 4. The reading device according to claim 3, wherein the flat gauge is provided with a plurality of first reference lines parallel to one another and a plurality of second reference lines perpendicular to the first reference lines and parallel to one another.

5. 5. The reading device according to claim 1, wherein the flat gauge is smaller than the image acquisition range.

6. a memory for storing a registered image including the reference scale and the flat gauge with the first reference line facing the main scanning direction; The reading device according to any one of claims 1 to 5, characterized in that the correction value calculation unit calculates the correction value indicating the amount of pixel movement required to bring the read image acquired by the optical sensor closer to the registered image stored in the memory.

7. 7. The reading device according to claim 6, wherein the correction value calculation unit updates the correction value in response to the reading device having operated for a predetermined operating time.

8. A reading device according to any one of claims 1 to 7; an image forming unit that forms the image acquired by the reading device on a sheet-like medium;

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