Reading device and image forming device

Abstract

To provide a reading device capable of simultaneously reading a reading object and a reference scale and improving measurement accuracy of the dimension of the reading object.SOLUTION: The reading device comprises: an optical sensor mounted on a carriage to scan an object placed on a contact glass; and reference scales serving as references for calculating the dimension of the object based on an image obtained by scanning the object by the optical sensor. The reference scales are disposed at a position outside an image acquisition range in which the optical sensor scans an object by the movement of the carriage and acquires the image of the object and inside a maximum movement range in which the carriage is movable so that the optical sensor acquires the image of the object, in a main scanning direction and a sub scanning direction with respect to the object.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] There are 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 transparent member such as glass, irradiating the object with light, detecting the reflected light, and generating data based on the shape of the object, etc.

[0003] One example of a conventional reading device is known, which has the function of placing a reference scale, which has scale marks formed at set intervals on a hard material, on a reading surface, reading an image of the reference scale, and measuring the positional information of the image of the scale portion in the read image to identify the positional relationship within the image (see Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] The reading device disclosed in Patent Document 1 is a so-called flat scanner, and the image of the reference scale is used to calibrate a reference for measuring the dimensions of an object to be read by image processing of the reading device. In the reading device of Patent Document 1, the image (image of the reference scale) needs to be acquired (read) at a timing different from the timing when the image of the measurement object (object to be read) is read. Therefore, there is a problem with the accuracy of measuring the dimensions of the object to be read from the image of the object to be read.

[0005] Another problem is that when a carriage that moves a sensor that optically reads an object to be read relative to the object to be read starts to move, speed fluctuations and carriage skew can cause an extreme drop in measurement accuracy.

[0006] Furthermore, conventional reading devices have the problem of operability because they require the attachment of a reference scale each time a measurement is made.

[0007] An object of the present invention is to provide a reading device that can simultaneously read an object to be read and a reference scale, thereby improving the accuracy of measuring the dimensions of the object to be read. [Means for solving the problem]

[0008] In order to solve the above technical problems, one aspect of the present invention comprises an optical sensor mounted on a carriage and scanning an object placed on a contact glass, and a reference scale serving as a reference for calculating the dimensions of the object based on an image acquired by the optical sensor scanning the object, wherein the reference scale is positioned outside an image acquisition range in which the optical sensor scans the object and acquires an image of the object as the carriage moves, and is positioned 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 arranged in a main scanning direction and a sub-scanning direction relative to the object, When the object is a three-dimensional object, a reference position for placing the three-dimensional object on the contact glass is near a turning position of the carriage in the sub-scanning direction and is a center position in the main scanning direction. It is characterized by: [Effects of the Invention]

[0009] According to the present invention, the object to be read and the reference scale are read simultaneously, and the measurement accuracy of the dimensions of the object to be read can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the overall configuration of an MFP as an embodiment of an image forming apparatus according to the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of the hardware configuration of a control unit included in the MFP. [Figure 3] FIG. 2 is a functional block diagram schematically showing the functional configuration of the MFP1. [Figure 4] 1 is a schematic diagram of an optical system provided in a scanner unit as an embodiment of a reading device according to the present invention. [Figure 5] FIG. [Figure 6]FIG. 3 is a diagram showing an example of the arrangement of a reference scale provided in the scanner unit. [Figure 7] 4 is a diagram illustrating a reading range when the object to be read by the scanner unit is a three-dimensional object; FIG. [Figure 8] 5A to 5C are diagrams showing an example of the operation of the scanner unit. [Figure 9] 6 is a flowchart showing a reading process that can be performed in the scanner unit. [Figure 10] 10 is a flowchart showing another example of a reading process that can be executed in the scanner unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] [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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] [Hardware configuration of the control unit in MFP1] Fig. 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, and a display unit 60, an operation unit 70, and a dedicated device 80 are connected to the I / F 50. The dedicated device 80 includes a scanner unit 100 and an image forming unit 200.

[0018] 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.

[0019] 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).

[0020] The operation unit 70 is a user interface that allows the user to input information to the MFP 1. The dedicated devices 80 include a scanner unit 100 and an image forming unit 200.

[0021] 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.

[0022] [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.

[0023] 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.

[0024] 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. 1.

[0025] 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 that has been 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. 1.

[0026] 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. 1.

[0027] 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. 1.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] [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.

[0034] 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 reflecting lens 1037 to enter the optical sensor 102. The optical sensor 102 is, for example, a CCD sensor.

[0035] 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.

[0036] 5 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. 5 (the surface on the depth side of the page) corresponds to the reading surface of the contact glass 101.

[0037] As shown in Fig. 5, scanner unit 100 has document size reference 1011 on the placement surface side of contact glass 101, which serves as a reference position when placing flat (sheet-like) read object B. Fig. 5 illustrates a standby state before scanner unit 100 starts a reading operation, so carriage 103 is on standby at carriage home position 1012. Carriage home position 1012 corresponds to the standby position of carriage 103 before starting scanning.

[0038] 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 carriage maximum reading area 1014 is 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.

[0039] FIG. 5 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.

[0040] Fig. 6 is a diagram showing an example of the arrangement of the reference scale 104 provided in the scanner unit 100. As shown in Fig. 6, the reference scale 104 includes a main scanning direction scale 1041 and a sub-scanning direction scale 1042.

[0041] Both the main scanning direction scale 1041 and the sub-scanning direction scale 1042 are arranged at positions that correspond to the outside of the maximum size reading area 1013 for flat media and the inside of the maximum carriage reading area 1014. In Fig. 6, the reference scale 104 is a member that arranges "scales" that function as a measurement standard for dimensions on the reading surface of the contact glass 101.

[0042] 6, the main scanning direction scale 1041 is arranged 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 1042 is arranged outside the end in the main scanning direction of the largest document size that can be read on the contact glass 101.

[0043] The reference scale 104 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).

[0044] Note that arranging the reference scale 104 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 104 is used to calibrate the optical sensor 102, it is essential to provide a scale on the lower surface (the carriage 103 side). In other words, the reference scale 104 may be arranged on both the upper and lower surfaces. Arranging the reference scale 104 on both surfaces allows the user to visually recognize the position of the reference scale 104, 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 104 and the read object B.

[0045] It is desirable that the surface of the reference scale 104 arranged on the carriage 103 side have a different color for displaying the scale and the color of the part where the scale is formed, so as not to reflect light from the light source mounted on the carriage 103. For example, the lines that display the scale 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.

[0046] Even if the reference scale 104 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.

[0047] Fig. 7 is a diagram illustrating the reading range when the object to be read B is a three-dimensional object. As shown in Fig. 7, 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.

[0048] 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 scale intervals of the sub-scanning direction scale 1042 are formed narrower than the scale intervals of the main scanning direction scale 1041. In other words, the sub-scanning direction scale 1042 is a finer reference scale 104 than the main scanning direction scale 1041.

[0049] [Example of scanner unit 100 operation] Next, an example of the operation of the scanner unit 100 will be described with reference to Fig. 8. Fig. 8(a) shows an example of an image acquired by performing a reading process on a flat object B to be read, which is an A3-sized sheet of paper P. In this case, an image is acquired within an area of ​​420 mm x 297 mm.

[0050] 8(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 104 are acquired simultaneously within an area of ​​440 mm x 305 mm.

[0051] 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 104, and a process of measuring the dimensions of the measurement target portion is carried out.

[0052] [First example of reading process flow] Fig. 9 is a flowchart showing an example of a reading process that can be executed by the scanner unit 100. The flowchart in Fig. 9 illustrates an example in which the reading target B is a three-dimensional object.

[0053] First, the pressure plate is opened (S901) in order 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.

[0054] Next, the object to be read B is placed on the placement surface of the contact glass 101 (S902).

[0055] Next, the "part measurement button" provided on the operation unit 70 is pressed to start the reading process (S903). When the reading process starts, first, the carriage 103 is operated (S904), and as the carriage 103 moves, the optical sensor 102 scans the object B to be read.

[0056] While moving the carriage 103 to the carriage maximum reading area 1014, the measurement target portion is scanned, and images of the reading target B and the reference scale 104 are simultaneously acquired and stored in a storage area (S905).

[0057] Next, the part of the image of the reference scale 104 included in the acquired image is identified, and the part of the image of the object to be read B is also identified, and the measurement process of the object to be read B is performed by comparing these identified images (S906).

[0058] Finally, the results of the measurement process are displayed on the display unit 60 (S907), and the process of reading the three-dimensional object is completed.

[0059] [Second example of reading process flow] Fig. 10 is a flowchart showing another example of a reading process that can be executed by the scanner unit 100. The flowchart in Fig. 10 illustrates a process in which the reading target B is a three-dimensional object and the user arbitrarily designates a measurement location.

[0060] As in the first example already described, first, in order to place the object B to be read on the placement surface of the contact glass 101, the pressure plate is opened (S1001), and the object B to be read is placed on the placement surface of the contact glass 101 (S1002). Thereafter, the "preview button" provided on the operation unit 70 is pressed to start the preview process (S1003).

[0061] 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 carriage 103 is operated (S1004), and the optical sensor 102 scans the object B to be read as the carriage 103 moves. While the carriage 103 is moved in the area (part measurement range 1015) set for reading the object B to be read, the measurement target portion is scanned, and an image of the object B to be read is simultaneously acquired (S1005) and saved in a storage area.

[0062] The image stored in the storage area is displayed as a preview image on the display unit 60 (S1006). Then, an operation to designate measurement points is performed on the image displayed on the display unit 60 via the operation unit 70 (S1007). After designation of the measurement points is completed, the "part measurement button" provided on the operation unit 70 is pressed to start the reading process (S1008).

[0063] When the reading process is started, the carriage 103 moves and the optical sensor 102 scans the object B to be read, and the carriage 103 scans the object B while moving to the carriage maximum reading area 1014. As a result, an image of the object B to be read in the range specified as the measurement location and an image of the reference scale 104 can be simultaneously acquired, and these are stored in a memory area (S1009).

[0064] Next, the image portion of the reference scale 104 included in the acquired image is identified, and also, the image portion of the image of the object B that is designated as the measurement target is identified, and these identified images are compared with each other. In this way, measurement processing of the object B is executed (S1010).

[0065] Finally, the results of the measurement process are displayed on the display unit 60 (S1011), and the process of reading the three-dimensional object is completed.

[0066] 9 and 10 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, the image processing unit 153 executes processing to identify each image portion for the scanned image obtained by simultaneously acquiring the images of the object to be read B and the reference scale 104. The result of this processing is passed to the main control unit 151, and the information required to calculate the dimensions of the object to be read B is collected, so the main control unit 151 executes a dimension calculation process.

[0067] That is, in this embodiment, a functional block including the main control unit 151 and the image processing unit 153 constitutes a dimension calculation unit.

[0068] As described above, the scanner unit 100 can simultaneously acquire images of the object to be read B and the permanent reference scale 104 by using the carriage 103 equipped with the optical sensor 102 below the contact glass 101. To enable this simultaneous acquisition, the reference scale 104 is positioned so that the range of part measurement when the object to be read B is a three-dimensional object is set to a different range from the range of the object to be read when the object to be read is a planar object.

[0069] For example, the maximum readable length of the object B is set to 297 mm in the main scanning direction and 420 mm in the sub-scanning direction. The maximum range within which the carriage 103 can move and which can be read by the optical sensor 102 is set to 306 mm in the main scanning direction and 435 mm in the sub-scanning direction. Then, the reference scale 104 is placed at a position outside the maximum readable length and inside the maximum readable range in both the main scanning direction and the sub-scanning direction.

[0070] With the above configuration, an image of the reference scale 104 and an image of the object to be read B can be acquired simultaneously, thereby significantly improving measurement accuracy.

[0071] Furthermore, since the reference scale 104 can be permanently attached to the scanner unit 100, the operability of the reading process is improved whether the object B to be read is a planar object or a three-dimensional object.

[0072] Furthermore, when the object to be read B is a planar object or a three-dimensional object, the scanning range of the optical sensor 102 for acquiring an image is set to a different range in each case.

[0073] For example, in the case of a planar object, the reference for the scanning range in the main scanning direction is set to the "rear reference," and the reference for the scanning range in the sub-scanning direction is set to the carriage home position 1012. In addition, in the case of a three-dimensional object, the reference for the scanning range in the main scanning direction is set to the "center reference," and the reference for the scanning range in the sub-scanning direction is set near the return position of the carriage 103.

[0074] By setting it in this way, in the main scanning direction, precision is improved by using the reading range based on the center of the optical path, which is highly precise with reduced optics. Also, in the sub-scanning direction, the influence of unevenness in the starting speed of the carriage 103 can be suppressed, thereby improving the reading precision of three-dimensional objects.

[0075] 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]

[0076] 1: MFP 100: Scanner unit 101: Contact glass 102: Optical sensor 103: Carriage 104: Reference scale 150: Controller 151: Main control unit 152: Engine control unit 153: Image processing unit 154: Operation display control unit 155: Input / output control unit 1012: Carriage home position 1013: Maximum size reading area for flat media 1014: Carriage maximum reading area 1015: Parts measurement range 1041: Main scanning scale 1042: Sub-scanning scale [Prior art documents] [Patent documents]

[0077] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-151548

Claims

1. an optical sensor mounted on the carriage for scanning 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; the reference scale is located outside an image acquisition range in which the optical sensor scans the object as the carriage moves to acquire an image of the object, and is located 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 arranged in a main scanning direction and a sub-scanning direction relative to the object; When the object is a three-dimensional object, a reference position for placing the three-dimensional object on the contact glass is near a turning position of the carriage in the sub-scanning direction and is a center position in the main scanning direction. A reading device characterized by:

2. a dimension calculation unit that calculates dimensions of the object based on the acquired image, the dimension calculation unit calculates dimensions of the object based on an image of a reference scale included in the image and arranged in the main scanning direction, an image of a reference scale included in the image and arranged in the sub-scanning direction, and an image of the object. The reading device according to claim 1 .

3. 3. The reading device according to claim 1, wherein the reference scale arranged in the main scanning direction and the reference scale arranged in the sub-scanning direction have different scale intervals.

4. 4. The reading device according to claim 3, wherein the interval between the graduations of the reference scale arranged in the sub-scanning direction is narrower than the interval between the graduations of the reference scale arranged in the main scanning direction.

5. The reading device according to claim 1 , wherein the carriage is equipped with a reduction optics including the optical sensor.

6. a medium transport unit that transports a sheet-shaped medium to the contact glass; A reading device according to any one of claims 1 to 5; an image forming unit that forms the image acquired by the reading device on a sheet-like medium;

Images