Document reading device and image forming apparatus

Abstract

To prevent leakage of information on a document not taken and left on a document placement table and the content of the document.SOLUTION: A document reading device comprises: a platen glass 7; a document holding member 3 that opens and closes a top face of the platen glass 7; and a lock mechanism 24 that locks the document holding member 3 at a closed position. A control unit 100, when a document is placed on the platen glass 7 after the document is read, causes the lock mechanism 24 to lock the document holding member 3 at the closed position.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an original reading device and an image forming apparatus that prevent information leakage of an original and its contents. [Background technology]

[0002] The following Patent Document 1 describes a technique for analyzing the document portion of a document using a document reader to search for terms that indicate the policy of the document, and forbidding printing according to the content of the policy indicated by the terms. The following Patent Document 2 describes a technique for inserting security information into content according to instructions from a user. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US8943603B2 [Patent Document 2] US20220043890A1 Summary of the Invention [Problem to be solved by the invention]

[0004] However, this prevents leakage of the contents written on the document, not the document that is the target of reading by the document reading device, and therefore cannot prevent leakage of both the document itself that the user leaves on the document placement table after reading the document, and the contents written on the document.

[0005] The present invention has been made in view of the above circumstances, and has an object to prevent information leakage of both an original left on an original placement table and the contents of the original. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided an original reading device comprising: an original placement plate on which an original is placed; an original detection unit which detects whether or not an original is present on the original placement plate; an original pressing member which is arranged to be freely opened and closed between a closed position which closes the top surface of the original placement plate and an open position which opens the top surface of the original placement plate; an original pressing member open / close detection unit which detects the opening and closing of the original pressing member; a locking mechanism which locks the original pressing member, which is in the closed position, to the closed position; an original reading unit which scans an original placed on the original placement plate; and a control unit which controls the locking and unlocking operations of the locking mechanism and the original reading operation of the original reading unit, and when the original detection unit detects that an original is present on the original placement plate after the original pressing member is read by the original reading unit while the open / close detection unit has detected that the original pressing member is in the closed position, the control unit causes the locking mechanism to lock the original pressing member in the closed position. Effect of the Invention

[0007] According to the present invention, if the user leaves the document on the document placement platform after scanning, the locking mechanism locks the document pressing member in the closed position, so that even if the user leaves the document reading device, a third party cannot take away the document on the document placement platform or read the document. Therefore, it is possible to prevent information leakage of both the document left on the document placement platform and the contents of that document. [Brief description of the drawings]

[0008] [Figure 1] 1 is a front cross-sectional view showing a structure of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] 1 is a block diagram showing an internal configuration of an image forming apparatus; [Diagram 3] 1 is a perspective view of an image forming apparatus showing a state in which the document pressing member is in an open position and the platen glass is opened; [Figure 4] 5 is a flowchart showing a first embodiment of operational control during document reading in the image forming apparatus. [Diagram 5] 13 is a diagram showing an example of a user information input screen. [Figure 6] 10 is a flowchart showing a second embodiment of operational control when reading a document in an image forming apparatus. [Figure 7] 10 is a flowchart showing a third embodiment of operational control when an image forming apparatus reads a document. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. An image forming apparatus 1 is one embodiment of an original reading device according to the present invention. Fig. 1 is a front cross-sectional view showing the structure of an image forming apparatus according to one embodiment of the present invention. Fig. 2 is a block diagram showing the internal configuration of the image forming apparatus. Fig. 3 is a perspective view of the image forming apparatus showing a state in which the original pressing member is in the open position and the platen glass is opened.

[0010] The image forming device 1 is a multifunction device equipped with multiple functions such as a copy function, a transmission function, a printing function, and a facsimile function. A housing of the image forming device 1 houses multiple devices for realizing the various functions of the image forming device 1. The image forming device 1 includes an original reading unit 11, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, and a conveying unit 17. A display unit 15 and an operation unit 16 are provided on the front of the housing of the image forming device 1.

[0011] The document reading unit 11 includes a document pressing member 3 incorporating a document transport unit 6 (ADF (Auto Document Feeder)) that transports a document placed on a document table, and a document reading mechanism that optically reads a document transported by the document transport unit 6 or a document placed on a platen glass 7 serving as a document placement table. The document reading mechanism illuminates the document with a light irradiation unit and receives the reflected light with a CCD (Charge-Couple device) sensor. The document reading unit 11 obtains a document image by reading the document. The document pressing member 3 is provided so as to be freely opened and closed between a closed position (a state in which the document pressing member 3 is in the position shown in FIG. 1) in which the document pressing member 3 comes into contact with the platen glass 7 and closes its upper surface, and an open position (a state in which the document pressing member 3 is in the position shown in FIG. 3) in which the document pressing member 3 opens the upper surface of the platen glass 7. The document pressing member 3 is attached to the upper edge of the rear side of the device body 120 by a hinge 51 so as to be freely rotatable about the edge of the document pressing member 3 as a rotation axis.

[0012] The document reading unit 11 reads the document by illuminating the document with a light emitting unit and receiving the reflected light with a CCD (Charge-Couple device) sensor to generate image data representing the document image. That is, the document reading unit 11 obtains the document image by reading the document.

[0013] The image forming unit 12 includes a photoconductor drum, a charging device, an exposure device, a developing device, and a transfer device. The image forming unit 12 forms an image composed of a toner image on the recording paper P conveyed along the conveying path T by the conveying unit 17 based on the image data generated by the document reading unit 11 or the image data received via the communication unit 22.

[0014] The fixing unit included in the image forming unit 12 applies heat and pressure to the recording paper P on which the toner image has been formed, thereby fixing the toner image to the recording paper P. The recording paper P on which the toner image has been fixed by the fixing unit is discharged to the discharge tray 8. The paper feed unit 14 includes a manual feed tray and multiple paper feed cassettes. The paper feed unit 14 pulls out the recording paper P stored in one of the multiple paper feed cassettes or the recording paper placed on the manual feed tray one by one using a pickup roller, and feeds the paper to the transport path T.

[0015] The display unit 15 is a display device configured with a liquid crystal display, an organic EL (Organic Light-Emitting Diode) display, etc. The display unit 15 displays various screens for each job that can be executed by the image forming apparatus 1 according to the control of the control unit 100.

[0016] The operation unit 16 includes a start key for inputting an instruction to start the execution of each job, and setting keys for receiving various instructions.

[0017] The transport unit 17 includes a transport roller pair 17A, a discharge roller pair 17B, etc., and a transport motor connected to the transport roller pair 17A and the discharge roller pair 17B, etc. The control unit 100 drives the transport motor to rotate the transport roller pair 17A and the discharge roller pair 17B, etc., thereby transporting the recording paper P fed by the paper feed unit 14 along the transport path T toward the image forming unit 12 and the discharge tray 8.

[0018] The image forming apparatus 1 includes a control unit 10. The control unit 10 includes a processor, a random access memory (RAM), a read only memory (ROM), etc. The processor is, for example, a central processing unit (CPU), a micro processing unit (MPU), or an application specific integrated circuit (ASIC).

[0019] The control unit 10 functions as a control unit 100, a user authentication unit 101, a document size detection unit 102, and a judgment unit 103 by the processor executing a control program stored in the ROM or the storage unit 18. Note that the control unit 100, the user authentication unit 101, the document size detection unit 102, and the judgment unit 103 may be configured by logic circuits, regardless of the operation based on the control program.

[0020] The control unit 100 is responsible for the overall control of the image forming apparatus 1. More specifically, the control unit 100 controls the operation of each unit of the image forming apparatus 1 and communication with an external device such as a PC (Personal Computer) connected via a network.

[0021] The control unit 100 is electrically connected to the document transport unit 6, the document reading unit 11, the image forming unit 12, the fixing unit 13, the paper feeding unit 14, the display unit 15, the operation unit 16, the transport unit 17, the memory unit 18, the image processing unit 19, the image memory 20, the facsimile communication unit 21, the communication unit 22, the document size detection unit 26, the open / close detection unit 27, and the human body detection unit 28, etc.

[0022] The user authentication unit 101 authenticates whether or not the user is a legitimate user based on user information input by the user to the operation unit 16. If the user information input to the operation unit 16 is identical to pre-stored legitimate user information, the user authentication unit 101 determines that the user is a legitimate user, and if the user information input to the operation unit 16 is not identical to the pre-stored legitimate user information, the user authentication unit 101 determines that the user is not a legitimate user.

[0023] In addition, the operation unit 16 may be equipped with a fingerprint reading device, and the user authentication unit 101 may authenticate whether the user is a legitimate user or not depending on whether the fingerprint read information acquired from the fingerprint reading device matches predetermined legitimate fingerprint information.

[0024] The document size detection unit 102 detects the document size of the document placed on the platen glass 7. Inside the device body 120 below the platen glass 7, optical sensors that emit light toward the platen glass 7 are provided at positions corresponding to standard document sizes. Each optical sensor includes a light emitting unit and a light receiving unit that receives the light reflected by the platen glass 7. Since the light receiving unit receives the reflected light when a document is placed on the platen glass 7, the document size detection unit 102 knows the standard size of the document placed on the platen glass 7 depending on which optical sensor arranged at each position it acquires an ON signal (when reflected light is received) or an OFF signal (when reflected light is not received).

[0025] The determination unit 103 determines (i) whether or not the document image obtained by document reading by the document reading unit 11 includes predetermined confidential information, or (ii) whether or not the document image obtained by document reading by the document reading unit 11 is a document image obtained by document reading by the document reading unit 11 in the past and is a document image when the control unit 100 locked the document pressing member 3 to a closed position by the lock mechanism 24. For example, the determination unit 103 executes OCR processing on the document image obtained by document reading by the document reading unit 11, converts character images included in the document image into characters and sets them as a character information group, and when it determines that characters indicating predetermined confidential information (for example, "confidential," "important document," "confidential," "contract," etc.) are included in the character information group, it determines that the document image obtained by document reading by the document reading unit 11 includes the predetermined confidential information. Furthermore, the determination section 103 stores all of the document images obtained by document reading by the document reading section 11, which are the document images when the control section 100 locks the document pressing member 3 in the closed position by the lock mechanism 24, in a non-volatile memory or the like built into the control unit 10 or in the storage section 18, and determines whether a document image obtained by a new document reading by the document reading section 11 matches these stored document images either entirely or partially to a predetermined extent (for example, 60%) using a pattern matching technique or the like. When both document readings match entirely or partially to a predetermined extent, the determination section 103 determines that the two images match.

[0026] The storage unit 18 is composed of a HDD (hard disk drive) or the like, and is a large-capacity storage device for storing various data such as image data generated by the document reading unit 11. The storage unit 18 stores various control programs for realizing general operations of the image forming apparatus 1.

[0027] The image processing unit 19 performs image processing as necessary on the image data generated by the document reading unit 11. The image memory 20 includes an area for temporarily storing the image data generated by the document reading unit 11. The facsimile communication unit 21 connects to a public line and transmits and receives image data via the public line.

[0028] The communication unit 22 includes a communication module such as a LAN (Local Area Network) board, etc. The image forming apparatus 1 performs data communication via the communication unit 22 with an external device such as a PC connected via a network.

[0029] Next, a description will be given of the mechanism around the document reading unit 11. Fig. 3 is a perspective view of the main part of the image forming apparatus 1, showing a state in which the document pressing member 3 is in an open position relative to the platen glass .

[0030] The document reading unit 11 is provided with a locking mechanism 24. The locking mechanism 24 is an electronic locking mechanism or an electromagnetic locking mechanism, and its operation is electronically controlled by the control unit 100. The locking mechanism 24 is provided separately at opposing positions on both the platen glass 7 and the document pressing member 3. Under the control of the control unit 100, the locking mechanism 24 performs a locking operation in which the document pressing member 3, which is in the closed position, is locked in the closed position to close the upper surface of the platen glass 7 so as not to open or close, and an unlocking operation in which the locking is released to allow the document pressing member 3 to rotate freely to open and close the upper surface of the platen glass 7.

[0031] The image forming apparatus 1 further includes a document detection unit 25 and an open / close detection unit 27. The document detection unit 25 detects whether or not a document is present on the platen glass 7. For example, the document detection unit 25 is provided inside the device body 120 below the platen glass 7, and in a case where one of the four corners of a rectangular area formed by the platen glass 7 is set as a document placement reference position A (FIG. 3), the document detection unit 25 is provided near the lower side of the reference position A. The document detection unit 25 is an optical sensor that irradiates light toward the platen glass 7. Each optical sensor includes a light emitting unit and a light receiving unit that receives the reflected light from the platen glass 7. The light receiving unit receives the reflected light when a document is placed on the platen glass 7. The document detection unit 25 outputs an ON signal indicating the presence of a document when it receives the reflected light, and outputs an OFF signal indicating the absence of a document when it does not receive the reflected light.

[0032] The open / close detection unit 27 is provided on the top surface of the device body 120, at a position facing the document pressing member 3 and outside the platen glass 7. The open / close detection unit 27 is made of a mechanical switch mechanism and has a pressed member exposed and protruding upward from the top surface of the device body 120, and when the lower part of the document pressing member 3 rotates to a position where it contacts the platen glass 7, the pressed member is pressed by the lower part of the document pressing member 3, and the switch mechanism detects ON. When detecting ON, the presser open / close detection unit 27 outputs an ON signal to the control unit 100, which indicates that the document pressing member 3 is in the closed position.

[0033] Furthermore, a human body detection unit 28 that detects a human being is disposed in the image forming apparatus 1. The human body detection unit 28 detects a human body within a predetermined range (e.g., 2 m) from the image forming apparatus 1. When the human body detection unit 28 detects a human body, it outputs a detection signal indicating the presence of a human body to the control unit 100. The human body detection unit 28 is, for example, an infrared sensor or a proximity sensor.

[0034] Next, a description will be given of a first embodiment of operational control when reading a document in the image forming apparatus 1. Fig. 4 is a flowchart showing a first embodiment of operational control when reading a document in the image forming apparatus 1.

[0035] A user inputs his / her own user information (for example, user-specific ID identification information) by operating the operation unit 16. When the user authentication unit 101 determines that the input user information is legitimate user information stored in advance, the control unit 100 permits the user (user information) to log in to the image forming apparatus 1. After permitting the login, the control unit 100 operates the image forming apparatus 1 in accordance with various instructions input to the operation unit 16.

[0036] Then, the user moves the document pressing member 3 to the open position (FIG. 3) to open the platen glass 7, places the document on the platen glass 7, and then moves the document pressing member 3 to the closed position (FIG. 1). In this state, the open / close detection unit 27 detects that the document pressing member 3 is in the closed position, and outputs the detection result to the control unit 100. In addition, the human body detection unit 28 detects the user's body within the predetermined range, and outputs the detection result to the control unit 100.

[0037] In the above state, when a document reading instruction is input to the operation unit 16 by a user's operation (YES in S1), the control unit 100 causes the document reading unit 11 to read the document on the platen glass 7 in accordance with the document reading instruction (S2).

[0038] After the document reading unit 11 has read the document, if the control unit 100 has received an ON signal from the open / close detection unit 27 indicating that the document pressing member 3 is in the closed position and an ON signal from the document detection unit 25 indicating that a document is on the platen glass 7 (YES in S3), the control unit 100 further determines whether it has received a detection signal from the human body detection unit 28 indicating that a human body has been detected (S4). Note that when the control unit 100 has received an OFF signal from the open / close detection unit 27 indicating that the document pressing member 3 is not in the closed position (NO in S3) after the document reading unit 11 has read the document, the process ends.

[0039] Here, when the control unit 100 determines that it has received a detection signal indicating that a human body has been detected from the human body detection unit 28 (YES in S4), it does not cause the lock mechanism 24 to lock the document pressing member 3 in the closed position, and the process repeats S3. That is, in this state, the document pressing member 3 is openable and closable relative to the platen glass 7, and the surface of the platen glass 7 is openable, so that the user can pick up the document on the platen glass 7.

[0040] On the other hand, when the control unit 100 determines that it has not received a detection signal indicating that a human body has been detected from the human body detection unit 28 (NO in S4), it causes the locking mechanism 24 to lock the document pressing member 3 in the closed position (S5). That is, in this state, the document pressing member 3 is fixed in the closed position relative to the platen glass 7, and the surface of the platen glass 7 cannot be opened, so that no one can pick up the document on the platen glass 7.

[0041] After the control unit 100 has locked the document pressing member 3 in the closed position by the lock mechanism 24 as described above, it further judges whether a human body has been detected again by the human body detection unit 28 (S6). If the control unit 100 judges that a human body has been detected again by the human body detection unit 28 (YES in S6), it causes the display unit 15 to display a user information input screen G1 including a message prompting the user to input user information (S7), as shown in Fig. 5 as an example. If the control unit 100 judges that a human body has not been detected again by the human body detection unit 28 (NO in S6), it continues the processes of S5 and S6.

[0042] When the user information input screen G1 is displayed and user information is input to the operation unit 16 by the user (YES in S8), the user authentication unit 101 judges whether the input user information is the same as the user information input at the time of login described above and whether it is the same as the predetermined administrator information (S9). When the user authentication unit 101 judges that the input user information is the same as the user information input at the time of login described above, it authenticates the user as a legitimate user, and when it judges that the input user information is the same as the administrator information (YES in S9), it causes the lock mechanism 24 to release the locked state (S10). When the control unit 100 judges that no user information has been input (NO in S8) or when the user authentication unit 101 judges that the input user information is not the same as the legitimate user information or the administrator information (NO in S9), the process returns to S7.

[0043] According to the above embodiment, if the user leaves the document on the platen glass 7 serving as the document placement platform after scanning, the locking mechanism 24 locks and fixes the document pressing member 3 in the closed position, so that a third party cannot take away the document on the platen glass 7 or read the document even if the user leaves the image forming apparatus 1. Therefore, it is possible to prevent information leakage of both the document left on the platen glass 7 and the contents of that document.

[0044] Next, a second embodiment of the operation control when reading a document in the image forming apparatus 1 will be described. Fig. 6 is a flowchart showing the second embodiment of the operation control when reading a document in the image forming apparatus 1. Note that in the description of the second embodiment, the description of the same processes as those in the first embodiment described above will be omitted.

[0045] In the second embodiment, after the document reading unit 11 reads the document, if the control unit 100 obtains an ON signal from the open / close detection unit 27 indicating that the document pressing member 3 is in the closed position and receives an ON signal from the document detection unit 25 indicating that a document is on the platen glass 7 (YES in S3), the control unit 100 judges whether the document size of the document placed on the platen glass 7 detected by the document size detection unit 102 is a predetermined size (S21). Here, the predetermined size refers to a predetermined size such as a standard A4 size, a standard B5 size, a standard B4 size, etc., which is often used for printing important documents containing confidential information, such as official documents, invoices, and contracts. For example, B6 size, A3 size, A5 size, etc. are rarely used for printing important documents containing confidential information, such as official documents, invoices, and contracts, and are therefore excluded from the above-mentioned predetermined sizes.

[0046] When the control unit 100 determines that the size of the document placed on the platen glass 7 detected by the document size detection unit 102 is the above-mentioned predetermined size (YES in S21), it causes the locking mechanism 24 to lock the document pressing member 3 in the closed position (S5). After that, the process proceeds to S7.

[0047] On the other hand, when the control unit 100 determines that the document size of the document placed on the platen glass 7 detected by the document size detection unit 102 is not the above-mentioned predetermined size (NO in S21), it does not cause the locking mechanism 24 to lock the document pressing member 3 in the closed position, and the process returns to S3.

[0048] According to the second embodiment, whether or not a misplaced document contains confidential information is determined by a simple method of judging the size of the document, so that only highly confidential documents can be selectively locked in the closed position by the document pressing member 3, thereby making it impossible for third parties to pick them up, through simple processing.

[0049] Next, a third embodiment of the operation control when reading a document in the image forming apparatus 1 will be described. Fig. 7 is a flowchart showing the third embodiment of the operation control when reading a document in the image forming apparatus 1. In the description of the third embodiment, the same processes as those in the first embodiment will not be described.

[0050] In the third embodiment, after the document reading unit 11 reads the document, if the control unit 100 obtains an ON signal from the open / close detection unit 27 indicating that the document holding member 3 is in the closed position and also receives an ON signal from the document detection unit 25 indicating that a document is on the platen glass 7 (YES in S3), the judgment unit 104 judges (i) whether or not the document image obtained by the document reading unit 11 reading the document contains predetermined confidential information, or (ii) whether or not the document image obtained by the document reading unit 11 reading the document is an original image obtained in a previous document reading by the document reading unit 11 and is an original image when the control unit 100 locked the document holding member 3 in the closed position using the locking mechanism 24 (S31).

[0051] When the determination unit 103 determines (i) whether or not the document image obtained by the document reading unit 11 reading the document contains predetermined confidential information, or (ii) whether the document image obtained by the document reading unit 11 reading the document is a document image obtained by a previous document reading by the document reading unit 11 and is a document image obtained when the control unit 100 locked the document pressing member 3 to the closed position by the locking mechanism 24 (YES in S31), the control unit 100 causes the locking mechanism 24 to lock the document pressing member 3 to the closed position (S5). After that, the process proceeds to S7.

[0052] On the other hand, when the control unit 100 determines through the judgment unit 103 that (i) the document image obtained by the document reading unit 11 reading the document contains predetermined confidential information, or (ii) that the document image obtained by the document reading unit 11 reading the document is not an document image obtained in a previous document reading by the document reading unit 11 and is not an document image obtained when the control unit 100 locked the document holding member 3 in the closed position using the locking mechanism 24 (NO in S31), the control unit 100 does not cause the locking mechanism 24 to perform the operation of locking the document holding member 3 in the closed position, and the process proceeds to S3.

[0053] According to the third embodiment, it is possible to selectively lock only highly confidential documents in the closed position by the document pressing member 3, thereby preventing third parties from picking them up.

[0054] In the above embodiment, the document reading device of the present invention is shown as an image forming device 1, but the document reading device of the present invention can also be applied to devices that do not have an image forming function as long as they have a document reading function.

[0055] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. The configuration and processing shown in the above embodiment using Figures 1 to 7 are merely one embodiment of the present invention, and the present invention is not limited to the configuration and processing. [Explanation of symbols]

[0056] 1. Image forming device 2 Document stand 3 Document holder 100 Control section 101 User authentication section 102 Document size detection unit 103 Judgment section 11 Document reading section 12 Image forming section 24 Locking mechanism 25 Document detection unit 27 Open / close detector 28 Human body detection unit

Claims

1. a document placement table for placing a document; a document detection unit that detects whether or not a document is present on the document placement table; a document pressing member that is provided so as to be able to open and close between a closed position that closes an upper surface of the document placement table and an open position that opens the upper surface of the document placement table; a document holder open / close detection unit that detects the opening / closing of the document holder; a locking mechanism for locking the document pressing member in a closed position; a document reading unit that scans a document placed on the document placement table; a control unit that controls a locking operation and an unlocking operation of the locking mechanism and a document reading operation of the document reading unit, The control unit, when the open / close detection unit detects that the document pressing member is in the closed position, causes the document reading unit to read the document placed on the document placing platen, and then, if the document detection unit detects that a document is present on the document placing platen, causes the locking mechanism to lock the document pressing member in the closed position.

2. a human body detection unit that detects whether or not a human body is present within a predetermined range from the document reading device, The control unit is When the human body is detected by the human body detection unit, even if the document detection unit detects the presence of a document on the document placement plate after the document reading unit reads the document, the document pressing member is not locked at the closed position by the lock mechanism, 2. The document reading device according to claim 1, wherein when the document detection unit detects the presence of a document on the document placing platen after the document reading unit reads the document, and the human body is not detected by the human body detection unit, the locking mechanism locks the document pressing member in a closed position.

3. an operation unit into which user information is input by a user operation; A user authentication unit is further provided for authenticating whether or not the user is a legitimate user based on user information input to the operation unit, The control unit is when the user authentication unit authenticates the user as a regular user, the document reading unit reads a document in accordance with a document reading instruction inputted to the operation unit; 2. The document reading device according to claim 1, wherein the locking mechanism releases the locked state when the user authentication unit determines that the user information input to the operation unit when the document pressing member is locked in the closed position by the locking mechanism is identical to the user information that was input to the operation unit when the document reading instruction was input.

4. The control unit further 4. The document reading device according to claim 3, wherein when the user information input to the operation unit while the document pressing member is locked in the closed position by the locking mechanism is determined by the user authentication unit to be identical to predetermined administrator information, the locked state is released by the locking mechanism.

5. a document size detection unit that detects the document size of the document placed on the document placement table, The control unit is when the document detection unit detects the presence of the document on the document placement platen after the document reading unit has read the document and the document size detected by the document size detection unit is a predetermined size, the document pressing member is locked in a closed position by the locking mechanism; 2. The document reading device of claim 1, wherein when the document size detected by the document size detection unit is not the predetermined size, the locking mechanism does not lock the document pressing member in the closed position even if the document detection unit detects that a document is present on the document placing table after the document is read by the document reading unit.

6. a determination unit that determines whether or not (i) an original image obtained by reading an original by the original reading unit includes predetermined confidential information, or (ii) an original image obtained by reading an original by the original reading unit is an original image obtained by a previous original reading by the original reading unit when the control unit locked the original pressing member in a closed position by the locking mechanism, The control unit is when the document detection unit detects the presence of a document on the document placement platen after the document reading unit has read the document, and the determination unit determines that the document image (i) includes predetermined confidential information, or (ii) is an image of the document when the control unit has locked the document pressing member to a closed position using the locking mechanism, locking the document pressing member to a closed position using the locking mechanism; 2. The document reading device of claim 1, wherein even if the document detection unit detects the presence of a document on the document placing platen after the document reading unit reads the document, if the determination unit does not determine that the document image (i) contains predetermined confidential information, or (ii) is the document image when the control unit locks the document pressing member in the closed position using the locking mechanism, the document reading device does not cause the locking mechanism to lock the document pressing member in the closed position.

7. A document reading device according to any one of claims 1 to 6, an image forming section for forming an image of the document obtained by reading the document using the document reading device on a recording sheet;

Images