Security paper detection device and security paper printing apparatus including the same

Abstract

The present invention relates to a detection device for security paper that can detect whether or not security paper is security paper, and a printing apparatus for security paper including the same. More specifically, the invention relates to a technology that can determine whether or not the paper is security paper, including a security paper detection sensor and a double-feed detection sensor. An embodiment of the present invention includes a double-feed detection sensor that utilizes ultrasonic transmission properties, comprising a transmitting unit and a receiving unit that can be installed separately from the printing device and are installed facing each other at a predetermined angle that is acute with respect to the paper transport path within the printing device; a security paper detection sensor installed in the paper transport path within the printing device so as to be in contact with the transported paper; and a control unit that determines whether or not the paper is double-feeded based on the detection value from the double-feed detection sensor, and determines whether the paper being fed is security paper or general paper based on the detection value from the security paper detection sensor, and if it is determined to be general paper or double-feed paper, it determines that incorrect paper is being transported and stops the printing function.

Description

Technical Field

[0001] The present invention relates to a security paper detection device capable of detecting the presence or absence of security paper using the security paper, and a printing device for security paper including the same. More specifically, the present invention relates to a technology including a security paper detection sensor and a double feed detection sensor, capable of determining the presence or absence of security paper. The printing device in the present invention includes not only a multifunction device integrating the functions of a printer, a fax machine, a copier, and a scanner, but also a device embodying only the individual functions of a printer, a fax machine, a copier, and a scanner.

Background Art

[0002] Recently, with the rapid development of enterprises, security solutions for the leakage of enterprise documents have been required. As such security solutions for document leakage, document security technologies applying security paper have been developed. Such security paper is paper that generates a signal capable of distinguishing the characteristics of substances in an alternating magnetic field in which an amorphous alloy is inserted into the paper.

[0003] Such security paper is detected by a sensor of an electromagnetic (EM) method from a gate. That is, when the amorphous alloy in the security paper approaches the alternating magnetic field generated by the sensor, Barkhausen Noise is generated from the amorphous alloy by the alternating magnetic field, and the presence or absence of the security paper is detected by detecting the harmonic spectrum of such a large Barkhausen Noise. Such a sensor can include a transmission coil that generates an alternating magnetic field, a reception coil that detects a change in the alternating magnetic field generated from the transmission coil, and an electronic system that controls the alternating magnetic field generated from the transmission coil and processes a signal received from the reception coil. Since the gate detects the security paper, the outflow of printed matter printed on the security paper can be prevented.

[0004] On the other hand, the primary magnetic field generated by the inductive sensor induces eddy currents in the amorphous alloy of the paper being fed. The secondary magnetic field generated by these eddy currents affects the primary magnetic field generated by the inductive sensor, changing its strength. Therefore, the inductive sensor transmits a safety paper detection signal to the control device depending on whether or not there is a change in the strength of the magnetic field it has generated. The printing device is then controlled so that printing proceeds only on safety paper and not on general paper that is not safety paper.

[0005] In the conventional technology described above, as shown in Figure 1, when printing with a security sheet attached to the back of a regular sheet of paper, the inductive sensor installed in the printing device recognizes the regular sheet as a security sheet based on the security sheet on the back, and printing proceeds normally. However, when the regular paper with the security sheet removed from the back of the printed material passes through the gate, the gate fails to detect the printed material on the regular paper, resulting in the printed material being ejected.

[0006] The reason is that the security paper detection sensor installed in the printing machine cannot precisely recognize the thickness of the paper. Therefore, even if there is regular paper directly in front of the security paper detection sensor, if there is security paper on the back of the regular paper, the sensor will recognize the substance contained in the security paper that can be identified as security paper (for example, metal wire). Consequently, a technology is needed that can accurately detect the presence or absence of security paper so that even if regular paper is attached to security paper and printed, it will not be recognized as security paper. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Republic of Korea Published Patent Gazette No. 10-2019-0014057 [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to solve the problems of the prior art described above, and to provide a security paper detection device that can accurately detect the presence or absence of security paper by precisely detecting multi-feeds, and a security paper printing device including the same. [Means for solving the problem]

[0009] According to an embodiment of the present invention, the security paper detection device includes a double-feed detection sensor that utilizes ultrasonic transmission characteristics, comprising a transmitting unit and a receiving unit that can be installed separately from the printing device and are installed facing each other at a predetermined angle that is acute with respect to the paper transport path within the printing device; a security paper detection sensor installed in the paper transport path within the printing device; and a control unit that determines whether or not the paper is double-feeded based on the detection value from the double-feed detection sensor, and determines whether the paper being fed is security paper or general paper based on the detection value from the security paper detection sensor, and if it is determined to be general paper or double-feed paper, it determines that incorrect paper is being transported and stops the printing function. [Effects of the Invention]

[0010] According to an embodiment of the present invention, a security paper detection device can be provided that includes a security paper detection sensor and a double-feed detection sensor, can accurately detect the presence or absence of security paper, and can be installed separately from the printing device.

[0011] Furthermore, according to an embodiment of the present invention, in the double-feed detection sensor, the double-feed detection performance can be improved by installing the transmitting unit and the receiving unit so as to face each other at a predetermined angle with respect to the paper transport path.

[0012] Furthermore, according to embodiments of the present invention, a printing apparatus for security paper can be provided that includes the security paper detection device and improves the security paper detection performance. [Brief explanation of the drawing]

[0013] [Figure 1] This is a diagram illustrating the problems with conventional technology. [Figure 2]This is a block diagram illustrating a security paper detection device according to an embodiment of the present invention. [Figure 3] This is a schematic diagram illustrating a security paper detection device according to an embodiment of the present invention. [Figure 4] This is a schematic diagram showing an example of the installation locations of the transmitter and receiver in a double-feed detection sensor. [Figure 5] This is a block diagram illustrating an example of the configuration of a double-feed detection sensor. [Figure 6] These are schematic diagrams and waveform diagrams for illustrating double feed detection according to an embodiment of the present invention. [Figure 7] This is a plan view showing an FPCB (Flexible Printed Circuit Board) on which a security paper detection sensor according to an embodiment of the present invention is installed. [Figure 8] This figure illustrates the spacing between the first optical sensor and the security paper detection sensor according to an embodiment of the present invention. [Figure 9] This figure illustrates the time point in time when the security paper detection sensor according to an embodiment of the present invention detects a first detection value, and the interval in which it detects a second detection value. [Figure 10] This is a block diagram illustrating a printing apparatus for security paper according to an embodiment of the present invention. [Modes for carrying out the invention]

[0014] An embodiment of the present invention includes a double-feed detection sensor that utilizes ultrasonic transmission characteristics, comprising a transmitting unit and a receiving unit that can be installed separately from the printing device and are installed facing each other at a predetermined angle that is acute with respect to the paper transport path within the printing device; a safety paper detection sensor installed in the paper transport path within the printing device; and a control unit that determines whether or not a paper has been double-feeded based on the detection value from the double-feed detection sensor, and determines whether the paper being fed is safety paper or general paper based on the detection value from the safety paper detection sensor, and if it is determined to be general paper or double-feed paper, it determines that incorrect paper is being transported and stops the printing function.

[0015] Also, regarding the embodiment, in the retransmission detection sensor, the transmission unit includes an ultrasonic transducer and an oscillator connected to the ultrasonic transducer, and the reception unit includes an ultrasonic transducer and an amplifier connected to the ultrasonic transducer.

[0016] Also, regarding the embodiment, the control unit includes a signal analysis unit connected to the amplifier.

[0017] Also, regarding the embodiment, the control unit is installed on the paper transfer path of the printing device, receives a signal from a sensor that detects whether the paper has reached the corresponding position, and after the paper reaches the installation position of the sensor, operates the retransmission detection sensor to determine whether the paper is a retransmitted paper.

[0018] Also, regarding the embodiment, it further includes an optical sensor for detecting the position of the paper on the paper transfer path, and the control unit receives a signal from the optical sensor that the paper has reached the installation position of the optical sensor, and after the paper reaches the installation position of the optical sensor, or after the security paper detection sensor detects whether the paper is security paper, operates the retransmission detection sensor to determine whether the paper is a retransmitted paper.

[0019] The printing apparatus for security paper according to an embodiment of the present invention comprises: a security paper detection device; a KCMY LED Head or LSU provided for commercial printing equipment to form an image to be printed on the printing paper; a plurality of sensors provided for commercial printing equipment to confirm the position of paper being transported along the paper transport path and installed on the paper transport path; a drive unit provided for commercial printing equipment to drive rollers so that paper is transported along the paper transport path; a printer engine controller provided for commercial printing equipment to transfer print data to the KCMY LED Head or LSU, receive sensor signals from the plurality of sensors, and drive the drive unit; and a control unit provided 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 drive unit, which controls the control unit of the security paper detection device to transmit the KCMY LED from the printer engine controller to the KCMY LED It includes a switching unit that switches the connection to the head or LSU on / off, switches the connection from any one of the plurality of sensors to the printer engine controller on / off, and switches the connection from the printer engine controller to the drive unit on / off. [Examples]

[0020] The following description will explain the security paper detection device and the security paper printing apparatus including the same according to the present invention, based on the attached drawings. The following description illustrates a preferred example of the present invention.

[0021] As mentioned above, the printing apparatus in this invention includes not only multifunction devices that integrate the functions of a printer, fax machine, copier, and scanner, but also devices that embody only the individual functions of a printer, fax machine, copier, and scanner. Generally, multifunction devices can embody all the functions of a printer, fax machine, copier, and scanner, but as can be seen from the description below, this invention distinguishes whether the paper being fed is general paper or special paper and performs the printing operation accordingly, so it may be understood to refer to a printer, fax machine, or copier that is not a multifunction device. In other words, even if a device functions only as a printer or copier, if it can embody the functions described below in this invention according to the paper being fed, it falls within the scope of this invention. On the other hand, a normal multifunction device that embodies all the functions mentioned above also naturally falls within the scope of this invention.

[0022] In this invention, "multi-feed" includes situations in which two or more sheets of paper are transported while stacked on top of each other, and situations in which two or more sheets of paper are transported attached to each other (this is referred to separately as "multi-layered paper," but both cases are included).

[0023] Figure 2 is a block diagram illustrating a security paper detection device according to an embodiment of the present invention, Figure 3 is a schematic diagram illustrating a security paper detection device according to an embodiment of the present invention, and Figure 4 is a schematic diagram showing an example of the installation positions of the transmitting unit and receiving unit in a double-feed detection sensor.

[0024] Referring to Figures 2, 3, and 4, the safety paper detection device 100 according to an embodiment of the present invention includes a double-feed detection sensor 110 that utilizes ultrasonic transmission characteristics, consisting of a transmitting unit 111 and a receiving unit 112 that are installed facing each other at a predetermined angle that is acute with respect to the paper transport path (A) in the printing device; a safety paper detection sensor 120 installed in the paper transport path (A) in the printing device; and a control unit 130 that determines whether or not the paper has been double-feeded based on the detection value from the double-feed detection sensor 110, and determines whether the paper being fed is safety paper or general paper based on the detection value from the safety paper detection sensor 120, and if it is determined to be general paper or double-feed paper, it determines that it is the transport of incorrect paper and stops the printing function.

[0025] The safety paper detection device 100 according to this embodiment can be installed separately from the printing device. Here, "can be installed separately" means that it can be installed as a separate device on an existing, normally functioning printing device, and it does not necessarily have to be installed physically outside the printing device.

[0026] As shown in Figure 4, in a commercial printing machine, the double feed detection sensor 110 can be installed with a transmitting unit 111 and a receiving unit 112 on the outer paper guide 1 and the inner paper guide 2, respectively, facing each other at a predetermined angle that is acute with respect to the paper transport path (A) formed between the outer paper guide 1 and the inner paper guide 2.

[0027] The double-feed detection sensor 110 may be installed in the paper transport path (A) before the security paper detection sensor 120, or it may be installed after the security paper detection sensor 120.

[0028] The control unit 130 ensures that, regardless of whether the safety paper detection sensor 120 is installed before or after the printer, the double feed detection sensor 110 detects whether a double feed has occurred simultaneously with the detection of the start of printing by the paper pickup sensor of the commercial printer. It is desirable that the ultrasonic sensor of the double feed detection sensor 110 operates only during the period when it is necessary to detect whether a double feed has occurred, under the control of the control unit 130. To this end, the control unit 130 can receive signals from sensors on the paper transport path, such as the paper pickup sensor of the commercial printer, and when it receives a signal from a sensor on the paper transport path installed immediately before the installation position of the double feed detection sensor 110 (for example, the paper pickup sensor), it activates the ultrasonic sensor of the double feed detection sensor 110 to detect whether the paper on the transport path where double feed detection is performed is double-fed or multiple sheets of paper.

[0029] The security paper detection sensor 120 detects whether or not amorphous alloy is present in the printing paper, and the double-feed detection sensor 110 detects whether or not the paper being fed is double-feeded.

[0030] The double-feed detection sensor 110 utilizes the characteristic that when ultrasonic waves generated from the transmitting unit 111 travel through an air layer and pass through paper (i.e., through another medium), refraction occurs in the direction of the ultrasonic waves' propagation. However, when a single sheet of paper passes through, i.e., in the order of air layer, paper, air layer, the refraction is small and occurs, reaching the receiving unit 112 on the opposite side. On the other hand, when multiple sheets of paper (double-feed or multi-layered paper) pass through, i.e., when passing through multiple diverse media such as air layer, paper, air layer, paper, air layer, the refraction is large and the ultrasonic waves do not reach the receiving unit 112 on the opposite side. Furthermore, by utilizing the characteristic that the refraction of ultrasonic waves becomes more intense when passing through as double-feed or multi-layered paper, regardless of the thickness of a single sheet of paper, due to other media such as the air layer between the sheets of paper, the detection performance is not greatly affected by the precision of the installation position or the thickness of the paper.

[0031] One method uses the reflection of sound waves (not ultrasound) to measure the distance to the paper from above and below, thereby determining whether or not it is a multi-layered sheet of paper. However, such methods generally need to detect paper thicknesses of around 0.1 mm, and at the same time, the precision of the sensor's placement must also be controlled to less than 0.1 mm, making it difficult to control errors caused by paper bending or movement. Furthermore, even with paper of the same thickness, it is difficult to distinguish between a single sheet of thick paper, multi-layered paper, or thick paper that has been fed multiple times.

[0032] Figure 5 is a block diagram illustrating an example of the configuration of a double-feed detection sensor.

[0033] Referring to Figure 5, in the double-feed detection sensor 110 according to the embodiment, 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. Furthermore, the control unit 130 according to the embodiment includes a signal analysis unit 131 connected to the amplifier 112b.

[0034] The double-feed detection sensor 110 uses ultrasound to detect whether or not a double feed is occurring. In the double-feed detection sensor 110, ultrasonic transducers 111a and 112a are installed on both sides of the paper transport path in the safety paper detection device 100, facing each other at a predetermined angle with respect to the paper transport path (A). Oscillator 111b generates a frequency pulse signal to drive ultrasonic transducer 111a. Ultrasonic transducer 111a receives the frequency pulse signal and transmits ultrasonic pulses to the paper transport path (A). In the paper transport path (A), the ultrasonic pulses pass through the transported paper (B) and reach ultrasonic transducer 112a. Ultrasonic transducer 112a receives the ultrasonic pulses and outputs a detection signal. The amplifier 112b amplifies the detection signal input from the ultrasonic transducer 112a and outputs it to the signal analysis unit 131 of the control unit 130. The signal analysis unit 131 analyzes the detection signal amplified by the amplifier 112b, allowing the control unit 130 to determine whether or not the paper (B) is being double-fed in the paper transport path (A). Although the ultrasonic medium transmission characteristics differ when there is one sheet of paper and when there are two sheets of paper, in the case of double-feeding or multiple sheets of paper, an air layer exists in between. As can be seen from the fact that the paper transport direction (C) and the dashed line (D) in Figure 5 have a predetermined angle (θ), if the transmitting unit 111 and the receiving unit 112 are positioned facing each other at a predetermined angle with respect to the paper transport path (A), and the air layer is located over a relatively long (wide) range relative to the transmitting unit 111 and the receiving unit 112, the effect of multiple reflections is reduced, and the medium transmission characteristics change significantly, making it easy to distinguish whether or not there is double-feeding. To reduce the effects of multiple reflections, it is desirable that the transmitting unit 111 and the receiving unit 112 be positioned opposite each other at an angle (θ) of 15° to 20° with respect to the paper transport direction (C). While the refraction characteristics from the same medium do not differ much with thickness, the refraction characteristics from medium 1 / medium 2 / medium 1 (where medium 1 is paper and medium 2 is the air layer) change significantly. Therefore, a single sheet of paper with the thickness of multiple sheets or double-feeding will not be detected as double-feeding.

[0035] Figure 6 is a schematic diagram and waveform diagram illustrating the double feed detection according to an embodiment of the present invention.

[0036] Figure 6(a) shows the case where there is one sheet of paper, Figure 6(b) shows the case where there is one sheet of paper that is relatively thicker than the one in Figure 6(a), and Figure 6(c) shows the case where the paper is fed in a double feed.

[0037] For example, as shown in Figure 6(a), when there is a single sheet of paper, and as shown in Figure 6(b), when there is a single sheet of paper that is relatively thicker than in Figure 6(a), the ultrasonic waves generated from the transmitting unit 111 pass through the paper and reach the receiving unit 112, showing a waveform. However, as shown in Figure 6(c), when there are double feeds of paper, the ultrasonic waves generated from the transmitting unit 111 do not reach the receiving unit 112 and do not show a waveform, so it is possible to determine whether or not there are double feeds.

[0038] Figure 7 is a plan view showing an FPCB (Flexible Printed Circuit Board) on which a security paper detection sensor according to an embodiment of the present invention is installed; Figure 8 is a diagram illustrating the spacing between the first optical sensor and the security paper detection sensor according to an embodiment of the present invention; and Figure 9 is a diagram illustrating the time when the security paper detection sensor according to an embodiment of the present invention detects the first detection value and the interval in which it detects the second detection value.

[0039] For example, referring to Figures 2 and 7, the security paper detection device 100 can be provided in the form of an FPCB(E), and the FPCB(E) is equipped with a first optical sensor 121 that detects the presence or absence of printed paper fed along the paper feeding direction of the printed paper, and security paper detection sensors 120 that are sequentially installed to detect whether or not the fed printed paper is security paper. The security paper detection sensor 120 detects a first detection value from the time when printed paper is detected by the first optical sensor 121 when no printed paper is detected, and thereafter detects one or more second detection values ​​for the printed paper being read along the paper feeding path within a predetermined time. Referring to Figure 9, F is 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, the safety paper detection sensor 120 detects a first detection value from the point when the waveform F changes from high to low. Subsequently, as the printing paper passes through within a predetermined time, the safety paper detection sensor 120 detects a second detection value for the printing paper. Referring to Figure 8, it is desirable that the distance between the first optical sensor 121 and the safety paper detection sensor 120 be smaller than the distance between the advanced printing paper and the next printing paper in the paper feed path. The reason is that the first detection value is detected when there is no printing paper at the position of the safety paper detection sensor 120, but if it is larger than the distance between the end of the advanced printing paper and the leading edge of the next printing paper, the first detection value will be detected when there is printing paper, making it impossible to accurately determine whether or not it is safety paper. The FPCB(E) according to the embodiment may include one or more holes, and the first optical sensor 121 may be installed in one of these holes, taking into consideration the spacing of the continuously fed printing paper of the printing device. Alternatively, the FPCB(E) according to the embodiment may include one or more holes, and the first optical sensor 121 may be installed in each hole, so that the FPCB(E) may include two or more first optical sensors 121 spaced apart along the paper feeding direction of the printing paper.In this case, the control unit 130, taking into consideration the interval between continuously fed sheets of printing paper in the printing apparatus used, selects a first optical sensor 121 from among two or more first optical sensors 121 that detects the presence or absence of fed printing paper, and controls the safety paper detection sensor 120 to detect a first detection value from the time when the selected first optical sensor 121 detects the printing paper. The safety paper detection sensor 120 installed in the FPCB(E) according to the embodiment is rod-shaped and installed perpendicular to the paper feeding direction of the printing paper, which allows for the detection of a wide surface area of ​​the printing paper in the lateral direction in a short time, thereby increasing the accuracy of safety paper detection. The printing paper contact portion of the FPCB(E) may further include a grounding metal pattern 123 that contacts the printing paper to remove static electricity. In the FPCB(E) according to the embodiment, a second optical sensor 122 can be installed after the safety paper detection sensor 120 in the paper feeding path of the printing paper. As shown in Figure 9, G is the output value of the second optical sensor 122, and at this time, the security paper detection sensor 120 detects the second detection value until the second optical sensor 122 detects the printed paper.

[0040] As a result, the security paper detection sensor 120 detects the magnetic field changes generated as the front portion of the incoming printing paper passes through. The security paper detection sensor 120 transmits the detected analog signal to the control unit 130, which converts the analog signal into a digital signal and compares the first detected value with one or more second detected values ​​detected by the security paper detection sensor 120. If the comparison value is above a predetermined standard, it is determined to be security paper; if it is below the predetermined standard, it is determined to be general paper.

[0041] If the double-feed detection sensor 110 is installed downstream of the safety paper detection sensor 120, the control unit 130 may also detect whether a double-feed has occurred with the double-feed detection sensor 110 after a predetermined time has elapsed since the safety paper detection sensor 120 detected a second detection value, or after a predetermined time has elapsed since the second optical sensor 122 detected the printed paper, without receiving a signal from the paper pickup sensor.

[0042] Figure 10 is a block diagram illustrating a printing apparatus for security paper according to an embodiment of the present invention.

[0043] Referring to Figure 10, the security paper printing apparatus 1000 according to an embodiment of the present invention includes: a KCMY LED Head or LSU (200) provided to a commercial printing apparatus that forms an image to be printed on the printing paper; a plurality of sensors 301, 302, 303 provided to a commercial printing apparatus that are installed on the paper transport path to confirm the position of the paper being transported along the paper transport path; a drive unit 400 provided to a commercial printing apparatus that drives rollers so that the paper is transported along the paper transport path; a printer engine controller 500 provided to a commercial printing apparatus that transfers print data to the KCMY LED Head or LSU (200), receives sensor signals from the plurality of sensors 301, 302, 303 and drives the drive unit 400; and the printer engine controller 500 and the KCMY LED The device includes a switching unit 600 provided between the Head or LSU(200), 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 drive unit 400, which, under the control of the control unit 130 of the safety paper detection device 100, switches the connection from the printer engine controller 500 to the KCMY LED Head or LSU(200) on / off, switches the connection from any one of the multiple sensors 301, 302, and 303 to the printer engine controller 500 on / off, and switches the connection from the printer engine controller 500 to the drive unit 400 on / off.

[0044] The printer engine controller 500, within the security paper printing device 1000, transfers print data to the KCMY LED Head or LSU (200), receives sensor signals from multiple sensors 301, 302, and 303, and drives the drive unit 400 to start the printing operation. The multiple sensors 301, 302, and 303 are, for example, a registration sensor, a door open sensor, an exit sensor, and a paper-in sensor. The drive unit 400 is a drive device generally provided in a printing device, such as various motors and clutches.

[0045] The control unit 130 of the security paper detection device 1000 controls the printing function of the security paper printer 1000 to selectively interrupt based on detection signals input from the double-feed detection sensor 110 and / or the security paper detection sensor 120. For example, if a detection signal corresponding to a double-feed is input from the double-feed detection sensor 110, or if no detection signal corresponding to security paper is input from the security paper detection sensor 120, the control unit 130 controls the printing function of the security paper printer 1000 to interrupt.

[0046] In this embodiment, when a double-feed detection sensor 110 is installed before the security paper detection sensor 120, the control unit 130 prioritizes detecting whether or not a double feed has occurred. Therefore, if the double-feed detection sensor 110 inputs a detection signal corresponding to a double feed and the control unit 130 determines that a double feed has occurred, even if the security paper detection sensor 120 inputs a detection signal corresponding to security paper, the control unit 130 processes it as general paper and interrupts the printing function of the security paper printing device 1000.

[0047] In this embodiment, when a double-feed detection sensor 110 is installed downstream of the security paper detection sensor 120, the control unit 130, while receiving a detection signal corresponding to security paper preferentially from the security paper detection sensor 120, receives a detection signal corresponding to a double feed from the double-feed detection sensor 110 and determines that a double feed has occurred, controls the security paper printing device 1000 to interrupt its printing function.

[0048] For example, the control unit 130, under the control of the switching unit 600, switches the signal transmitted from the printer engine controller 500 to the KCMY LED Head or LSU (200) to turn off the connection and interrupt the printing function. Alternatively, for example, the control unit 130 switches the signal transmitted from one of the multiple sensors 301, 302, and 303 to the printer engine controller 500 to turn off the connection and interrupt the printing function. Alternatively, for example, the control unit 130 switches the signal transmitted from the printer engine controller 500 to the drive unit 400 to turn off the connection and interrupt the printing function of the safety paper printing device 1000.

[0049] As explained above, the present invention is not limited to the specific preferred inventions described above, and any person with ordinary skill in the art to which the invention belongs can carry out a variety of modifications without departing from the gist of the claims, and such modifications are within the scope of the claims. [Industrial applicability]

[0050] We can provide a security paper detection device that can precisely detect double feeding and accurately determine whether or not a paper is security paper, as well as a security paper printing apparatus including the same.

Claims

1. A double-feed detection sensor utilizing ultrasonic transmission characteristics, comprising a transmitting unit and a receiving unit, which are installed facing each other at a predetermined angle that is acute with respect to the paper transport path within the printing device, A safety paper detection sensor is installed in the paper transport path within the printing device so as to come into contact with the transported paper, A security paper detection device that can be installed in a printing apparatus, comprising a control unit that determines whether or not a paper has been double-fed based on a value detected from the double-feed detection sensor, and determines whether the paper being fed is security paper or general paper based on a value detected from the security paper detection sensor, and if it is determined to be general paper or double-feed paper, determines that it is the transfer of incorrect paper and stops the printing function.

2. The double-feed detection sensor is characterized in that 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, as described in claim 1.

3. The security paper detection device according to claim 2, characterized in that the control unit includes a signal analysis unit connected to the amplifier.

4. The security paper detection device according to claim 1, characterized in that the predetermined angle is 15° to 20°.

5. The safety paper detection device according to claim 1, characterized in that the control unit is installed on the paper transport path of a printing device and receives a signal from a sensor that detects whether or not paper has reached the corresponding position, and after the paper has reached the installation position of the sensor, operates the double-feed detection sensor to determine whether or not the paper has been double-feeded.

6. The security paper detection device according to claim 1, further comprising an optical sensor for detecting the position of paper on the paper transport path, wherein the control unit receives a signal from the optical sensor that the paper has reached the installation position of the optical sensor, and after the paper has reached the installation position of the optical sensor, or after the security paper detection sensor has detected whether or not it is security paper, operates the double-feed detection sensor to determine whether or not the paper has been double-feeded.

7. The security paper detection device according to any one of claims 1 to 6, A KCMY LED Head or LSU, provided for commercial printing equipment, which forms the image to be printed on printing paper, A commercial printing machine is provided with multiple sensors installed along the paper transport path to confirm the position of paper being transported along that path, A drive unit provided for commercial printing equipment that drives rollers so that paper is transported along a paper transport path, A printer engine controller provided for a commercial printing device, which transfers print data to the KCMY LED Head or LSU, receives sensor signals from the multiple sensors, and drives the drive unit, A printing apparatus for security paper, characterized by including a switching unit provided 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 drive unit, which, under the control of the control unit of the security paper detection device, switches the connection from the printer engine controller to the KCMY LED Head or LSU on and off (ON / OFF), switches the connection from any one of the plurality of sensors to the printer engine controller on and off (ON / OFF), and switches the connection from the printer engine controller to the drive unit on and off (ON / OFF).

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