Safety paper detection apparatus and safety paper printing apparatus including same

Abstract

The present invention relates to a security paper detection apparatus capable of detecting whether to use security paper by using the security paper and a security paper printing apparatus including the security paper detection apparatus, and more particularly, to a technology capable of determining whether to use security paper by including a security paper detection sensor and a re-feed detection sensor. A safety paper detection apparatus according to an embodiment of the present invention may be mounted separately from a printing apparatus, and includes: a re-feed detection sensor that uses an ultrasonic transmission feature and is constituted by a transmitting unit and a receiving unit that are mounted at positions facing each other at a predetermined angle, i.e., an acute angle, with respect to a paper conveyance path in the printing apparatus; a safety paper detection sensor mounted to be in contact with paper conveyed in a paper conveying path in the printing apparatus; and a control unit that determines whether the paper is refed paper based on a detection value from the refeed detection sensor, determines whether the fed paper is safe paper or normal paper based on a detection value from the safe paper detection sensor, and determines that the paper is wrongly conveyed if the paper is determined to be normal paper or refed paper, therefore, the printing function is stopped.

Description

Technical Field

[0001] This disclosure relates to a security paper detection device capable of detecting the presence of security paper by using security paper, and a security paper printing apparatus including the security paper detection device. More specifically, it relates to a technique capable of determining the presence of security paper by including a security paper detection sensor and a double-feed detection sensor. In this disclosure, the term "printing apparatus" includes not only multifunctional devices that combine the functions of a printer, fax machine, copier, and scanner, but also devices that only perform the functions of a printer, fax machine, copier, or scanner. Background Technology

[0002] Recently, with the rapid development of enterprises, security measures to prevent document leaks are being designed. One such measure is the development of document security technology using security paper. Security paper refers to paper with an amorphous alloy embedded in it, which generates signals that can distinguish the material properties within an alternating magnetic field.

[0003] Such security paper is detected at the gate by an electromagnetic (EM) sensor. Specifically, when the amorphous alloy in the security paper approaches the alternating magnetic field generated by the sensor, Barkhausen noise is generated in the amorphous alloy due to the alternating magnetic field. The presence of security paper can be determined by detecting the harmonic spectrum of this large Barkhausen noise. The sensor may include: a transmitting coil that generates the alternating magnetic field; a receiving coil that senses changes in the alternating magnetic field generated by the transmitting coil; and an electronic system that controls the alternating magnetic field generated by the transmitting coil and processes the signal received by the receiving coil. Because the security paper is detected at the gate, leakage of printed material on the security paper can be prevented.

[0004] Alternatively, the primary magnetic field generated by the inductive sensor induces eddy currents in the amorphous alloy within the fed paper, and the secondary magnetic field generated by these eddy currents influences the primary magnetic field generated by the inductive sensor, thereby altering its intensity. Therefore, the inductive sensor sends a safety paper detection signal to the control unit based on whether there is a change in the intensity of its generated magnetic field. This controls the printing equipment so that printing occurs only on safety paper and not on ordinary paper.

[0005] In the aforementioned prior art, such as Figure 1As shown, when printing is performed after attaching security paper to the back of the printing surface of regular paper, the inductive sensor installed in the printing equipment recognizes the presence of the security paper because it is attached to the back, thus allowing normal printing to proceed. However, if the security paper is removed from the back of the printing surface after printing and the regular paper is carried through the gate, the printed matter on the regular paper cannot be detected at the gate, resulting in leakage of the printed matter.

[0006] This is because the security paper detection sensor installed in the printing equipment cannot accurately identify the thickness of the paper. Therefore, even if plain paper is placed directly in front of the security paper detection sensor, if security paper is attached to the back of the plain paper, the sensor will detect materials (such as metal threads) contained in the security paper, and can identify the security paper by these materials. Therefore, a technology is needed to accurately detect the presence of security paper when attempting to print on plain paper with security paper attached, so as to prevent the plain paper from being identified as security paper.

[0007] Existing technical documents

[0008] (Patent Document) Korean Patent Publication No. 10-2019-0014057 Summary of the Invention Technical issues

[0009] This disclosure is designed to address the problems of the prior art described above, and its purpose is to provide a security paper detection device capable of accurately detecting the presence of security paper by precisely detecting refeeding, and a security paper printing device including the security paper detection device. Technical solution

[0010] According to embodiments of this disclosure, a safety paper detection device can be installed separately from the printing device and includes: a refeed detection sensor that utilizes ultrasonic transmission characteristics and is composed of a transmitting unit and a receiving unit installed at opposite positions relative to the paper transport path in the printing device at a predetermined angle, i.e., an acute angle; a safety paper detection sensor installed in the paper transport path in the printing device; and a control unit that determines whether the paper is refeeding based on the detection value from the refeed detection sensor, determines whether the paper is safety paper or ordinary paper based on the detection value from the safety paper detection sensor, and if the paper is determined to be ordinary paper or refeeding paper, determines that the paper has been incorrectly fed, thereby stopping the printing function. Effects of the present invention

[0011] According to embodiments of this disclosure, by including a security paper detection sensor and a refeed detection device, a security paper detection device that can accurately detect the presence of security paper and can be installed separately from the printing device can be provided.

[0012] Furthermore, according to embodiments of this disclosure, since the transmitting unit and receiving unit in the refeed detection sensor are mounted opposite each other at a predetermined angle relative to the paper transport path, the refeed detection performance can be improved.

[0013] Furthermore, according to embodiments of this disclosure, a safety paper printing apparatus can be provided that improves safety paper detection performance by including the safety paper detection device. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating the problems with the existing technology.

[0015] Figure 2 This is a block diagram illustrating a security paper detection device according to an embodiment of the present disclosure.

[0016] Figure 3 This is a schematic diagram illustrating a security paper detection device according to an embodiment of the present disclosure.

[0017] Figure 4 This is a schematic diagram illustrating an example of the installation positions of the transmitting and receiving units in a retransmission detection sensor.

[0018] Figure 5 This is a block diagram illustrating an example configuration of a refeed detection sensor.

[0019] Figure 6 This is a diagram and waveform illustrating a retransmission detection according to an embodiment of the present disclosure.

[0020] Figure 7 This is a plan view showing an FPCB (flexible printed circuit board) on which a safety paper detection sensor is mounted, according to an embodiment of the present disclosure.

[0021] Figure 8 This is a diagram showing the spacing between the first optical sensor and the security paper detection sensor according to an embodiment of the present disclosure.

[0022] Figure 9 This is a diagram showing the time point at which the safety paper detection sensor detects the first detection value and the time period during which the second detection value is detected, according to an embodiment of the present disclosure.

[0023] Figure 10 This is a block diagram illustrating a security paper printing apparatus according to an embodiment of the present disclosure. Detailed Implementation

[0024] The safety paper detection device according to embodiments of this disclosure can be installed separately from the printing device and includes: a refeed detection sensor that utilizes ultrasonic transmission characteristics and is composed of a transmitting unit and a receiving unit installed at opposite positions relative to the paper transport path in the printing device at a predetermined angle, i.e., an acute angle; a safety paper detection sensor installed in the paper transport path in the printing device; and a control unit that determines whether the paper is refeeding based on the detection value from the refeed detection sensor, determines whether the paper is safety paper or ordinary paper based on the detection value from the safety paper detection sensor, and if the paper is determined to be ordinary paper or refeeding paper, determines that the paper has been incorrectly fed, thereby stopping the printing function.

[0025] Furthermore, according to an embodiment, the transmitting unit includes an ultrasonic transducer and an oscillator connected to the ultrasonic transducer, and the receiving unit includes an ultrasonic transducer and an amplifier connected to the ultrasonic transducer.

[0026] Furthermore, according to an embodiment, the control unit includes a signal analysis unit connected to the amplifier.

[0027] Furthermore, according to the implementation, the control unit receives signals from sensors installed on the paper feed path in the printing device to detect whether the paper has reached the corresponding position, and after the paper has reached the sensor's installation position, it determines whether the paper is to be re-fed by activating the re-feed detection sensor.

[0028] Furthermore, according to the embodiment, the security paper detection device also includes an optical sensor that detects the position of the paper on the paper transport path. The control unit receives a signal from the optical sensor indicating that the paper has reached the installation position of the optical sensor. After the paper has reached the installation position of the optical sensor or after the security paper detection sensor has detected whether the paper is security paper, the control unit activates the refeed detection sensor to determine whether the paper is refeeding paper.

[0029] A security paper printing apparatus according to embodiments of this disclosure includes: a security paper detection device; a KCMY LED head or LSU disposed in a commercial printing apparatus to form an image to be printed on printing paper; a plurality of sensors disposed in the commercial printing apparatus and mounted on the paper transport path to check the position of paper transported along the paper transport path; an actuation unit disposed in the commercial printing apparatus for actuating rollers to transport paper along the paper transport path; a printer engine controller disposed in the commercial printing apparatus for sending printing data to the KCMY LED head or LSU, receiving sensor signals from the plurality of sensors, and driving the actuation unit; and a switching unit disposed between the printer engine controller and the KCMY LED head or LSU, between the printer engine controller and any one of the plurality of sensors, and between the printer engine controller and the actuation unit, and controlled by a control unit of the security paper detection device to turn on / off a connection from the printer engine controller to the KCMY LED head or LSU, to turn on / off a connection from any one of the plurality of sensors to the printer engine controller, or to turn on / off a connection from the printer engine controller to the actuation unit. Mode of implementing the present invention

[0030] In the following description, a security paper detection apparatus and a security paper printing apparatus including a security paper detection apparatus according to the present disclosure will be described with reference to the accompanying drawings. The preferred embodiments of the present disclosure are described below.

[0031] As described above, the term "printing equipment" as used herein includes not only multifunction devices that combine the functions of a printer, fax machine, copier, and scanner, but also devices that perform only the functions of a printer, fax machine, copier, or scanner. Generally, a multifunction device refers to a device capable of performing all the functions of a printer, fax machine, copier, and scanner. However, as will be apparent from the following description, since this disclosure involves distinguishing between plain paper and security paper and performing printing accordingly, the term "printing equipment" may also be understood to refer only to a printer, fax machine, or copier. That is, even if the device is used only as a printer or only as a copier, it still falls within the scope of this disclosure if it performs the functions described below depending on the paper fed to it. Alternatively, a conventional multifunction device that performs all the functions described above naturally also falls within the scope of this disclosure.

[0032] In this disclosure, the term "double-feed" includes both cases where two or more sheets of paper are overlapped and fed at once and cases where two or more sheets of paper are glued together and fed at once (sometimes referred to separately as "overlap feed," but both are included herein).

[0033] Figure 2 This is a block diagram illustrating a security paper detection device according to an embodiment of the present disclosure. Figure 3 This is a schematic diagram illustrating a security paper detection device according to an embodiment of the present disclosure. Figure 4 This is a schematic diagram illustrating an example of the installation positions of the transmitting and receiving units in a retransmission detection sensor.

[0034] Reference Figure 2 , Figure 3 and Figure 4 According to an embodiment of the present disclosure, a safety paper detection device 100 includes: a refeed detection sensor 110 that utilizes ultrasonic transmission characteristics and is composed of a transmitting unit 111 and a receiving unit 112 mounted at a predetermined angle, i.e., an acute angle, relative to the paper transport path A in the printing device; a safety paper detection sensor 120 that is mounted in the paper transport path A in the printing device; and a control unit 130 that determines whether the paper is refeeding based on the detection value from the refeed detection sensor 110, determines whether the paper is safety paper or ordinary paper based on the detection value from the safety paper detection sensor 120, and if the paper is determined to be ordinary paper or refeeding paper, determines that the paper has been incorrectly fed, thereby stopping the printing function.

[0035] According to the implementation method, the safety paper detection device 100 can be installed separately from the printing device. Here, the statement "can be installed separately" means that the device is installed as an independent unit in the existing printing device that is in normal operation, and does not necessarily need to be physically installed outside the printing device.

[0036] like Figure 4 As shown, the sending unit 111 and receiving unit 112 of the refeeding detection device 110 can be installed at the outer paper guide 1 and the inner paper guide 2 in a commercial printing device, such that the sending unit 111 and the receiving unit 112 are opposite each other at a predetermined angle, i.e., an acute angle, relative to the paper transport path A formed between the outer paper guide 1 and the inner paper guide 2.

[0037] The refeed detection sensor 110 can be installed at the front end of the safety paper detection sensor 120 along the paper transport path A, or at the rear end of the safety paper detection sensor 120 along the paper transport path A.

[0038] Control unit 130 controls refeed detection sensor 110 to begin refeed detection simultaneously with (and simultaneously with) the paper pickup sensor in the commercial printing equipment detecting that paper has been picked up, regardless of whether the refeed detection sensor 110 is installed before or after the safety paper detection sensor 120. Preferably, the ultrasonic sensor of refeed detection sensor 110 operates only during the time period when refeed should be detected, under the control of control unit 130. For this purpose, control unit 130 can receive signals from sensors (such as paper pickup sensors) on the paper transport path of the commercial printing equipment. When a signal is received from a sensor (e.g., a paper pickup sensor) installed immediately before the mounting position of refeed detection sensor 110, control unit 130 activates the ultrasonic sensor of refeed detection sensor 110, enabling the detection of refeeding or overlapping feeding of paper on the transport path.

[0039] The safety paper detection sensor 120 detects the presence of amorphous alloy in the printing paper, and the refeed detection sensor 110 detects whether the paper being fed is refeed paper.

[0040] When the ultrasonic wave generated from the transmitting unit 111 travels through the air layer and then through the paper (i.e., different media), the direction of travel of the ultrasonic wave is refracted. When the ultrasonic wave passes through a single sheet of paper, i.e., in the order of air layer, paper, and air layer, the ultrasonic wave is not refracted to a large extent and does not reach the receiving unit 112 on the opposite side. On the other hand, when the ultrasonic wave passes through multiple sheets of paper (re-fed or overlapped), i.e., passing through multiple different media such as air layer, paper, air layer, paper, and air layer, the ultrasonic wave is refracted to a large extent and does not reach the receiving unit 112 on the opposite side. Utilizing this characteristic, when the ultrasonic wave passes through re-fed or overlapped paper, the ultrasonic wave is refracted to a large extent due to the different media such as the air layer between the two sheets, regardless of the thickness of the single sheet of paper. This is advantageous because the detection performance is not greatly affected by the accuracy of the installation position or the thickness of the paper.

[0041] One method for determining whether sheets of paper overlap is to calculate paper thickness by using sound reflection instead of ultrasonic reflection to measure the distance to the paper from the top and bottom. However, in this method, the thickness of the paper to be detected is typically around 0.1 mm, meaning the sensor's mounting position needs to be precisely controlled to within 0.1 mm. Furthermore, it is difficult to control errors caused by paper bending, movement, etc. Additionally, even for papers of the same thickness, it is difficult to distinguish between a single thick sheet and multiple overlapping or re-fed sheets.

[0042] Figure 5 This is a block diagram illustrating an example configuration of a refeed detection sensor.

[0043] Reference Figure 5 According to an embodiment, in the retransmission detection sensor 110, the transmitting unit 111 includes an ultrasonic transducer 111a and an oscillator 111b connected to the ultrasonic transducer 111a, and the receiving unit 112 includes an ultrasonic transducer 112a and an amplifier 112b connected to the ultrasonic transducer 112a. Additionally, according to an embodiment, the control unit 130 includes a signal analysis unit 131 connected to the amplifier 112b.

[0044] The refeed detection sensor 110 detects the presence of refeed using ultrasonic waves. In the refeed detection sensor 110, ultrasonic transducers 111a and 112a are mounted on opposite sides of the paper transport path A in the safety paper detection device 100, positioned relative to each other at a predetermined angle. An oscillator 111b generates a frequency pulse signal to drive the ultrasonic transducer 111a. The ultrasonic transducer 111a receives the frequency pulse signal and sends ultrasonic pulses into the paper transport path A. The ultrasonic pulses pass through the fed paper B and reach the ultrasonic transducer 112a. The ultrasonic transducer 112a receives the ultrasonic pulses and outputs a detection signal. An amplifier 112b amplifies the detection signal input from the ultrasonic transducer 112a and outputs it to a signal analyzer 131 in the control unit 130. The signal analyzer 131 analyzes the detection signal amplified by the amplifier 112b, enabling the control unit 130 to determine whether the paper B in the paper transport path A is a refeed. The medium transmission characteristics of ultrasound differ between single sheets and two sheets of paper. In cases of re-feeding or overlapping feeding, an air layer exists between the sheets. For example... Figure 5 As shown, when the paper transport direction C forms a predetermined angle θ with the imaginary line D, the sending unit 111 and the receiving unit 112 are positioned relative to the paper transport path A at a predetermined angle, such that the air layer is located within the relative length (width) range between the sending unit 111 and the receiving unit 112. This reduces the influence of multiple reflections and significantly alters the medium transport characteristics, thereby facilitating the detection of re-feeding. To reduce the influence of multiple reflections, it is preferable to position the sending unit 111 and the receiving unit 112 relative to each other at an angle θ of 15 to 20 degrees relative to the paper transport direction C. Refraction within the same medium does not change significantly with thickness. However, in the case of refraction across medium 1 / medium 2 / medium 1 (where medium 1 is paper and medium 2 is air), the refractive characteristics change significantly. Therefore, a single sheet of paper whose thickness is equivalent to being over-fed or re-fed will not be detected as re-fed paper.

[0045] Figure 6 This is a diagram and waveform illustrating a retransmission detection according to an embodiment of the present disclosure.

[0046] Figure 6 (A) shows the situation where a single sheet of paper is being fed in. Figure 6 (B) shows that it is being fed into Figure 6 The thickness of (A) is compared to that of a single sheet of paper with a relatively greater thickness. Figure 6 (C) shows the situation where the paper is being re-fed.

[0047] For example, in such Figure 6 As shown in (A), in the case of a single sheet of paper, and in the case of... Figure 6 The existence shown in (B) is related to Figure 6 In the case of (A) a relatively thicker sheet of paper, the ultrasonic waves generated by the transmitting unit 111 pass through the paper and reach the receiving unit 112, thereby generating a waveform. On the other hand, as Figure 6 As shown in (C), when the paper is being re-fed, the ultrasonic waves generated by the transmitting unit 111 do not reach the receiving unit 112, and therefore no waveform appears, making it possible to determine whether the paper is being re-fed.

[0048] Figure 7 This is a plan view showing an FPCB (flexible printed circuit board) on which a safety paper detection sensor is mounted, according to an embodiment of the present disclosure. Figure 8 This is a diagram showing the spacing between the first optical sensor and the security paper detection sensor according to an embodiment of the present disclosure. Figure 9 This is a diagram showing the time point at which the safety paper detection sensor detects the first detection value and the time period during which the second detection value is detected, according to an embodiment of the present disclosure.

[0049] For example, refer to Figure 2 and Figure 7 The security paper detection device 100 can be provided in the form of an FPCB(E). On the FPCB(E), a first optical sensor 121 is mounted to detect the presence of printed paper being fed along the paper feed direction, and subsequently, a security paper detection sensor 120 is mounted to detect whether the fed printed paper is security paper. The security paper detection sensor 120 only detects printed paper when the first optical sensor 121 detects the paper to be read, at which point the security paper detection sensor 120 detects a first detection value. Thereafter, the security paper detection sensor 120 detects one or more second detection values ​​for printed paper read along the feed path within a predetermined time period. (See reference...) Figure 9 F represents the output value of the first optical sensor 121. When the printing paper enters and the output value of the first optical sensor 121 changes—specifically, when the waveform F shifts from high to low—the security paper detection sensor 120 detects the first detection value. Thereafter, the security paper detection sensor 120 detects a second detection value of the printing paper for a predetermined time during the paper's passage. (Refer to...) Figure 8Preferably, the interval between the first optical sensor 121 and the security paper detection sensor 120 is smaller than the distance between the printed paper and subsequent printed paper along the feed path. This is because the first detection value needs to be sensed when there is no printed paper at the location of the security paper detection sensor 120. However, if the interval is greater than the distance between the trailing edge of the previous sheet and the leading edge of the next sheet, the first detection value may be sensed even when printed paper is present, making it impossible to accurately determine the presence of security paper. According to an embodiment, the FPCB(E) may include one or more holes, and the first optical sensor 121 may be installed in one of the holes, taking into account the interval between consecutively fed printed papers in the printing device. In another embodiment, the FPCB(E) may include one or more holes, and the first optical sensor 121 may be installed in each hole, thereby the FPCB(E) includes two or more first optical sensors 121 spaced apart along the paper feed direction. In this case, taking into account the interval between consecutively fed printed papers in the printing device in use, the control unit 130 selects the first optical sensor 121 from the two or more first optical sensors 121 that detects the presence of fed printed paper. When the selected first optical sensor 121 detects the paper to be read, the security paper detection sensor 120 is controlled to detect a first detection value. According to an embodiment, the security paper detection sensor 120 mounted on the FPCB(E) may be in the form of a strip arranged perpendicular to the paper feed direction. In this case, a large area in the lateral direction of the paper can be detected in a short time, thereby improving the accuracy of security paper detection. The paper contact portion of the FPCB(E) may additionally include a grounded metal pattern 123, which removes static electricity by contacting the paper. According to an embodiment, the FPCB(E) may include a second optical sensor 122 mounted behind the security paper detection sensor 120 along the paper feed path. (See also...) Figure 9 G represents the output value of the second optical sensor 122. In this case, the security paper detection sensor 120 detects the second detection value until the second optical sensor 122 detects the printing paper.

[0050] Therefore, the safety paper detection sensor 120 detects the change in magnetic field caused by the front part of the input printing paper passing through it. The safety paper detection sensor 120 sends the detected analog signal to the control unit 130, and the control unit 130 converts the analog signal into a digital signal, then compares the first detection value with one or more second detection values ​​detected by the safety paper detection sensor 120. If the comparison value is greater than a predetermined threshold, the paper is determined to be safety paper; if the comparison value is less than or equal to the predetermined threshold, the paper is determined to be ordinary paper.

[0051] With the refeed detection sensor 110 installed behind the security paper detection sensor 120, the control unit 130 does not receive signals from the paper pickup sensor. Alternatively, the refeed detection sensor 110 may begin detecting whether a refeed exists after a predetermined time following the security paper detection sensor 120 detecting the second detection value or after a predetermined time following the second optical sensor 122 detecting the printed paper.

[0052] Figure 10 This is a block diagram illustrating a security paper printing apparatus according to an embodiment of the present disclosure.

[0053] Reference Figure 10 According to an embodiment of this disclosure, a security paper printing apparatus 100 includes: a KCMY LED head or LSU 200 disposed in a commercial printing apparatus for forming an image to be printed on printing paper; a plurality of sensors 301, 302, and 303 disposed in the commercial printing apparatus and mounted on the paper transport path to check the position of paper transported along the paper transport path; an actuation unit 400 disposed in the commercial printing apparatus for actuating rollers to transport paper along the paper transport path; a printer engine controller 500 disposed in the commercial printing apparatus for sending printing data to the KCMY LED head or LSU 200, receiving sensor signals from the plurality of sensors 301, 302, and 303, and driving the actuation unit 400; and a switching unit 600 disposed between the printer engine controller 500 and the KCMY LED head or LSU 200. The connection between the printer engine controller 500 and any one of the multiple sensors 301, 302 and 303, and between the printer engine controller 500 and the actuator 400, and controlled by the control unit 130 of the safety paper detection device 100, is turned on / off to connect / disconnect the printer engine controller 500 to the KCMY LED head or LSU 200, to connect / disconnect any one of the multiple sensors 301, 302 and 303 to the printer engine controller 500, or to connect / disconnect the printer engine controller 500 to the actuator 400.

[0054] The printer engine controller 500 within the safety paper printing apparatus 1000 sends print data to the KCMY LED head or LSU 200, receives sensor signals from multiple sensors 301, 302, and 303, and drives the actuator unit 400 to perform the printing operation. The multiple sensors 301, 302, and 303 include, for example, a registration sensor, a door open sensor, an eject sensor, and a paper feed sensor. The actuator unit 400 is an actuator typically located in a printing apparatus and may include, for example, various motors and clutches.

[0055] The control unit 130 of the safety paper detection device 100 selectively suspends the printing function of the safety paper printing device 1000 based on the detection signals input from the refeed detection sensor 110 and / or the safety paper detection sensor 120. For example, when a detection signal corresponding to refeed is input from the refeed detection sensor 110, or when no detection signal corresponding to safety paper is input from the safety paper detection sensor 120, the control unit 130 controls the safety paper printing device 1000 to suspend its printing function.

[0056] According to the embodiment, when the refeed detection sensor 110 is installed at the front end of the security paper detection sensor 120, the presence of refeed is detected first. Therefore, when it is determined that a refeed exists based on the detection signal corresponding to the refeed input from the refeed detection sensor 110, even if a detection signal corresponding to security paper is subsequently input from the security paper detection sensor 120, the control unit 130 will treat the paper as ordinary paper and control the security paper printing device 1000 to suspend its printing function.

[0057] According to the implementation, when the refeed detection sensor 110 is installed at the rear end of the safety paper detection sensor 120, when a detection signal corresponding to the safety paper has already been input from the safety paper detection sensor 120, and a refeed is determined to exist based on the detection signal corresponding to the refeed input from the refeed detection sensor 110, the control unit 130 controls the safety paper printing device 1000 to suspend its printing function.

[0058] For example, control unit 130 controls switching unit 400 to switch signals from printer engine controller 500 to KCMY LED head or LSU 200, thereby disconnecting the connection and pausing the printing function. Alternatively, for example, control unit 130 controls switching unit 400 to switch signals from any of the plurality of sensors 301, 302, and 303 to printer engine controller 500, thereby disconnecting the connection and pausing the printing function. Furthermore, for example, control unit 130 controls switching unit 400 to switch signals from printer engine controller 500 to drive unit 400, thereby disconnecting the connection and controlling the safety paper printing device 1000 to pause its printing function.

[0059] As described above, this disclosure is not limited to the specific preferred embodiments described above. Those skilled in the art to which this disclosure pertains can make various modifications without departing from the spirit of this disclosure as claimed in the claims, and such modifications are within the scope of the claims. Industrial applicability

[0060] A security paper detection device and a security paper printing device including the security paper detection device can be provided. The security paper detection device can accurately detect the presence of security paper because it is capable of performing precise refeed detection.

Claims

1. A security paper detection device capable of being installed in a printing device, comprising: a re-feed detection sensor that utilizes an ultrasonic transmission characteristic and is composed of a transmitting unit and a receiving unit installed at positions opposite to each other at a predetermined angle, i.e., an acute angle, with respect to a paper conveying path in the printing device; a security paper detection sensor installed to come into contact with a paper conveyed in the paper conveying path in the printing device; and a control unit that determines whether the paper is a re-fed paper based on a detection value from the re-feed detection sensor, determines whether the paper fed in is a security paper or a regular paper based on a detection value from the security paper detection sensor, and determines that the paper is conveyed in error if the paper is determined to be a regular paper or a re-fed paper, thereby stopping a printing function. The transmitting unit includes an ultrasonic transducer and an oscillator connected to the ultrasonic transducer, and the receiving unit includes an ultrasonic transducer and an amplifier connected to the ultrasonic transducer.

2. The security paper detection apparatus according to claim 1, wherein, The control unit includes a signal analysis unit connected to the amplifier.

3. The security paper detection apparatus of claim 2, wherein, The predetermined angle is 15 to 20 degrees.

4. The security paper detection apparatus of claim 1, wherein, The control unit receives a signal from a sensor installed on the paper conveying path in the printing device to detect whether the paper has reached a corresponding position, and determines whether the paper is a re-fed paper by activating the re-feed detection sensor after the paper has reached the installation position of the sensor.

5. The security paper detection apparatus of claim 1, wherein, 6. The security paper detection device according to claim 1, further comprising an optical sensor that detects a position of the paper on the paper conveying path, The control unit receives a signal from the optical sensor indicating that the paper has reached the installation position of the optical sensor, and the control unit activates the re-feed detection sensor to determine whether the paper is a re-fed paper after the paper has reached the installation position of the optical sensor or after the security paper detection sensor has detected whether the paper is a security paper. wherein 7. A security paper printing device, comprising: the security paper detection device according to any one of claims 1 to 6; a KCMY LED head or LSU provided in a commercial printing device for forming an image to be printed on a printing paper; a plurality of sensors provided in a commercial printing device and installed on a paper conveying path to check a position of the paper conveyed along the paper conveying path; an actuating unit provided in a commercial printing device for actuating a roller to convey a paper along the paper conveying path; a printer engine controller provided in a commercial printing device for transmitting print data to the KCMY LED head or LSU, receiving a sensor signal from the plurality of sensors, and driving the actuating unit; and a control unit that determines whether the paper is a re-fed paper based on a detection value from the re-feed detection sensor, determines whether the paper fed in is a security paper or a regular paper based on a detection value from the security paper detection sensor, and determines that the paper is conveyed in error if the paper is determined to be a regular paper or a re-fed paper, thereby stopping a printing function. ​ A switching unit is provided between the printer engine controller and the KCMY LED head or LSU, between the printer engine controller and any of the plurality of sensors, and between the printer engine controller and the actuating unit, and is controlled by the control unit of the security paper detection apparatus to turn on / off the connection from the printer engine controller to the KCMY LED head or LSU, to turn on / off the connection from any of the plurality of sensors to the printer engine controller, or to turn on / off the connection from the printer engine controller to the actuating unit.

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