Printing apparatus

Abstract

To provide a printing apparatus that can accurately determine the remaining amount of recording paper and improve the design flexibility of the pivot mechanism. [Solution] A printing apparatus comprising: a media storage section that houses a roll body containing recording paper wound in a roll shape around a cylindrical core material; a shaft support mechanism having a shaft inserted through the core material and supporting the roll body through which the shaft is inserted within the media storage section; a print head that prints on the recording paper pulled out from the roll body by rotation; and a remaining amount detection circuit that detects the remaining amount of recording paper stored in the media storage section, wherein the remaining amount detection circuit comprises an optical tracking sensor that irradiates light onto a detection surface of the roll body that intersects with the rotation axis of the roll body and detects the reflected light, and a determination circuit that determines the remaining amount of recording paper based on the detection result of the optical tracking sensor, wherein the relative position of the optical tracking sensor with respect to the core material is substantially constant during the period in which the optical tracking sensor is performing detection.

Description

Technical Field

[0001] This invention relates to a printing apparatus.

Background Art

[0002] Research and development have been conducted on a printing apparatus that prints an image on a recording paper drawn from a roll body including a recording paper wound in a roll shape.

[0003] Regarding this, as a shaft for supporting the roll body, there is known a printing apparatus provided with a shaft support mechanism having a shaft that rotates together with the roll body, and determining the remaining amount of the recording paper drawn from the roll body based on the rotation speed of the shaft (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the printing apparatus as described in Patent Document 1, the shaft of the shaft support mechanism needs to rotate together with the roll body. For this reason, it has been difficult for the printing apparatus to achieve both accurately determining the remaining amount of the recording paper and improving the design freedom of the shaft support mechanism in some cases.

Means for Solving the Problems

[0006] To solve the above problems, one aspect of the present invention is a printing apparatus comprising: a media storage section that houses a roll body containing recording paper wound in a roll shape around a cylindrical core material having a cavity formed in the center; a shaft support mechanism having a shaft inserted through the cavity of the core material and supporting the roll body through which the shaft is inserted within the media storage section; a print head that prints on the recording paper pulled out from the roll body by rotation; and a remaining amount detection circuit that detects the remaining amount of the recording paper stored in the media storage section, wherein the remaining amount detection circuit comprises an optical tracking sensor that irradiates light onto a detection surface of the roll body that intersects with the rotation axis of the roll body and detects the reflected light, and a determination circuit that determines the remaining amount of the recording paper based on the detection result of the optical tracking sensor, wherein the relative position of the optical tracking sensor with respect to the core material is substantially constant during the period in which the optical tracking sensor is performing detection. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing an example of the external structure of the printing device 1. [Figure 2] This diagram schematically shows an example of the internal structure of the printing device 1, and is a side view of the inside of the printing device 1 from the +X side along the X axis. [Figure 3] This figure shows an example of the configuration of the pivot mechanism 40. [Figure 4] This diagram illustrates the relationship between the amount of recording paper P pulled from the roll R and the rotation speed of the roll R. [Figure 5] This figure illustrates that the tangential velocity of the roll body R at the detection surface DM increases monotonically as the recording paper P is pulled out. [Figure 6] This figure shows an example of the functional configuration of the printing device 1. [Figure 7] This figure shows an example of the configuration of the remaining amount detection circuit 170. [Figure 8] This diagram illustrates the recommended position on the side of the roll body R where light should be irradiated as the detection surface DM. [Figure 9]This diagram shows an example of the process flow for the printing device 1 to determine the remaining amount of recording paper P. [Figure 10] This figure shows an example of the configuration of the lens 50 provided in the printing apparatus 1 according to a modified embodiment. [Modes for carrying out the invention]

[0008] <Embodiment> Embodiments of the present invention will be described below with reference to the drawings.

[0009] <Overview of Printing Equipment> First, an overview of the printing apparatus according to this embodiment will be described.

[0010] The printing apparatus according to this embodiment comprises a media storage section, a support mechanism, a print head, and a remaining amount detection circuit. The media storage section houses a roll containing recording paper wound in a roll shape around a cylindrical core material with a hollow in its center. The support mechanism has a shaft inserted through the hollow of the core material and supports the roll body through which the shaft is inserted within the media storage section. The print head prints on the recording paper pulled out from the roll body by rotation. The remaining amount detection circuit detects the remaining amount of recording paper stored in the media storage section. The remaining amount detection circuit includes an optical tracking sensor and a determination circuit. The optical tracking sensor irradiates light onto a detection surface of the roll body that intersects with the rotation axis of the roll body and detects the reflected light. The determination circuit determines the remaining amount of recording paper based on the detection result of the optical tracking sensor. During the period in which the optical tracking sensor is performing detection, the relative position of the optical tracking sensor with respect to the core material is substantially constant.

[0011] As a result, the printing apparatus according to this embodiment suppresses changes in the position of the optical tracking sensor relative to the roll body, and eliminates the need to provide the optical tracking sensor in the pivot mechanism. Consequently, the printing apparatus can accurately determine the remaining amount of recording paper and improve the design flexibility of the pivot mechanism. The configuration of the printing apparatus will be described in detail below.

[0012] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The drawings used are for convenience of explanation. Also, the embodiments described below do not unduly limit the content of the present invention described in the claims. Also, not all of the configurations described below are essential components of the present invention.

[0013] <Schematic Structure of Printing Device>

[0014] The printing device 1 of the present embodiment will be described by exemplifying a thermal printer that executes a printing process of forming an image on a recording paper P such as thermal paper. Note that the printing device 1 is not limited to a thermal printer, and may be an inkjet printer, a laser printer, or the like. The schematic structure of the printing device 1 of the present embodiment will be described. FIG. 1 is a perspective view showing an example of the external structure of the printing device 1. Here, in the following description, the explanation will be made using the X-axis, Y-axis, and Z-axis that are orthogonal to each other. Also, in the following description, the starting point side of the arrow along the illustrated X-axis is referred to as the -X side, the tip side is referred to as the +X side, the starting point side of the arrow along the illustrated Y-axis is referred to as the -Y side, the tip side is referred to as the +Y side, the starting point side of the arrow along the illustrated Z-axis is referred to as the -Z side, and the tip side is referred to as the +Z side.

[0015] As shown in FIG. 1, the printing device 1 includes a main body case 2, an opening / closing door 3, a discharge port 4, a notification unit 5, a power switch 6, and an opening / closing lever 7.

[0016] The main body case 2 has a substantially rectangular parallelepiped shape as a whole, excluding the concave and convex portions such as buttons. The recording paper P is accommodated inside the main body case 2. In the printing device 1 of the present embodiment, the opposing surfaces of the substantially rectangular parallelepiped-shaped main body case 2 are positioned so as to face along the X-axis, Y-axis, and Z-axis, respectively.

[0017] The opening / closing door 3 forms part of the +Y side surface of the main case 2. The opening / closing door 3 is also provided to be openable and closable on the +Y side surface of the main case 2. In the printing device 1 of this embodiment, the opening / closing lever 7 is located near the opening / closing door 3 and on the +Z side of the opening / closing door 3. The user can open the opening / closing door 3 by operating the opening / closing lever 7 and using the hinge portion 8 shown in Figure 2 as the axis of rotation. This allows the user to access the inside of the main case 2, and the user can store recording paper P in the media storage section 30, which will be described later, provided inside the main case 2.

[0018] The discharge port 4 is located on the +Y side of the main case 2 and on the +Z side of the opening / closing door 3. Furthermore, the discharge port 4 is inserted into the interior of the main case 2. The recording paper P printed inside the main case 2 of the printing device 1 is discharged to the outside of the printing device 1 through the discharge port 4.

[0019] The notification unit 5 includes, for example, multiple LEDs. The notification unit 5 displays information regarding the status of the printing device 1 by flashing, lighting, or extinguishing the LEDs. Specifically, the notification unit 5 notifies information regarding the status of the printing device 1, such as information regarding the printing status of the printing device 1, information regarding the communication status of the printing device 1, and information regarding the recording paper P on which the printing device 1 prints. Because such a notification unit 5 plays the role of informing the user of the status of the printing device 1, it is installed in a location that is easily visible to the user. For example, the notification unit 5 is installed near the output port 4, but is not limited to this. Furthermore, the notification unit 5 is not limited to multiple LEDs, but may be a liquid crystal display device, or it may be configured to notify the user of information by sound such as a buzzer or speaker. In addition, the notification unit 5 may be a touch panel in which the operation panel for performing various settings and operations of the printing device 1 and the liquid crystal display device are integrated.

[0020] The power switch 6 is located on the +Y side of the main case 2 and is provided on the opening / closing door 3. The power switch 6 accepts operations to start and stop the printing device 1. By operating the power switch 6, for example, the power supplied to the printing device 1 via a power cable (not shown) may be switched on or off to supply power to various components of the printing device 1, thereby controlling at least one of the starting and stopping of the printing device 1. Alternatively, the starting and stopping of the printing device 1 may be controlled by restricting the printing process on the recording paper P or communication with external devices connected to the printing device 1.

[0021] Figure 2 is a schematic diagram showing an example of the internal structure of the printing device 1, and is a side view of the inside of the printing device 1 from the +X side along the X axis. As shown in Figure 2, the printing device 1 has a transport roller 12, a movable blade 14a, a fixed blade 14b, a paper detection sensor 15, an encoder 16, an open / close sensor 19, a media remaining amount sensor 20, a media storage section 30, and a print head 200 inside the main body case 2.

[0022] The media storage section 30 houses the roll body R. The media storage section 30 may have any configuration as long as it is capable of accommodating the roll body R, as long as it does not interfere with the functions of the printing apparatus 1 described herein. In Figure 2, for the sake of simplicity, the media storage section 30 is shown by a rectangular dotted line.

[0023] The roll body R includes recording paper P and a core material C. The core material C is a cylindrical member with a cavity H formed in the center. The roll body R is formed by winding the recording paper P in a roll shape around the core material C. In other words, the roll body R includes the core material C around which the recording paper P is wound.

[0024] Here, the media storage section 30 is provided with a support mechanism 40, which is not shown in Figure 2. The support mechanism 40 has a shaft 41 that is inserted into the cavity H of the core material C, and supports the roll body R through which the shaft 41 is inserted within the media storage section 30.

[0025] Figure 3 shows an example of the configuration of the support mechanism 40. The support mechanism 40 has a shaft 41 that is inserted into the cavity H of the core material C. The support mechanism 40 supports the roll body R through which the shaft 41 is inserted within the media storage section 30. The support mechanism 40 has, for example, a shaft 41 and a structure 42.

[0026] The shaft 41 is a cylindrical or columnar member supported by the structure 42. The shaft 41 may be rotatably supported relative to the structure 42, or it may be non-rotatably supported relative to the structure 42. If the shaft 41 is rotatably supported relative to the structure 42, the shaft 41 rotates together with the roll body R through which the shaft 41 is inserted. On the other hand, if the shaft 41 is non-rotatably supported relative to the structure 42, the shaft 41 does not rotate relative to the structure 42, even if the roll body R through which the shaft 41 is inserted rotates.

[0027] The structure 42 may have any configuration as long as it is capable of supporting the shaft 41. In the example shown in Figure 3, the structure 42 has a bottom member located below the shaft 41 and two rectangular prism members extending upward from the bottom member, and the shaft 41 is supported by the two rectangular prism members sandwiching it. In this example, the structure 42 is provided with a media remaining amount sensor 20, which will be described later. However, the media remaining amount sensor 20 is provided such that, during the period in which the media remaining amount sensor 20 is detecting the amount of media, the relative position of the media remaining amount sensor 20 with respect to the core material C remains substantially constant, excluding displacement due to vibration, etc. However, the media remaining amount sensor 20 may not be provided on the structure 42 but on another member, as long as it does not impair the function of the printing apparatus 1 described herein. This means that the printing apparatus 1 can improve the design freedom of the shaft support mechanism 40. Also, the light IL shown in Figure 3 is an example of laser light irradiated from the media remaining amount sensor 20 toward one of the two sides of the roll body R. The two sides in question are the two surfaces of the roll body R that intersect with the rotation axis of the roll body R. For the sake of explanation, the side of the roll body R that is irradiated with light IL from the media remaining amount sensor 20 will be referred to as the irradiated side. Also, for the sake of explanation, the region on the irradiated side that is actually irradiated with light IL will be referred to as the detection surface.

[0028] As described above, the roll body R, supported within the media storage section 30 by the pivot mechanism 40, is housed in the media storage section 30 such that the cavity H of the core material C extends along the X-axis. Then, the recording paper P is pulled out from the roll body R by the rotation of the transport roller 12, which will be described later. At this time, the roll body R rotates with the axis through which the cavity H of the core material C extends as its axis of rotation. Here, in the following description, the direction of the roll body R along the axis through which the cavity H of the core material C extends may be referred to as the width direction of the roll body R. That is, in the printing apparatus 1 of this embodiment shown in Figure 2, the roll body R is housed in the media storage section 30 such that its width direction extends along the X-axis and its side surface extends along the plane formed by the Y-axis and Z-axis. Here, the side surface of the roll body R is the surface formed by the recording paper P and the core material C, and does not include the cavity H of the core material C. Alternatively, the roll body R may not include the core material C, and the recording paper P may be wound into a roll. In this case, the side surface of the roll body R is the surface formed by the recording paper P, and does not include a cavity through which the shaft 41 is inserted in the roll body R.

[0029] In the printing apparatus 1 of this embodiment, which employs a pivot mechanism 40 supporting a roll body R, the rotational speed of the roll body R changes as recording paper P is pulled out from the roll body R. The rotational speed of the roll body R increases as the amount of recording paper P pulled out from the roll body R increases. The rotational speed of the roll body R is the angular velocity of the roll body R around its axis of rotation. Therefore, the tangential velocity at each position on the side surface of the roll body R also increases as the amount of recording paper P pulled out from the roll body R increases. Furthermore, a large amount of recording paper P pulled out from the roll body R is equivalent to a small amount of recording paper P remaining. The tangential direction at a certain position on the side surface of the roll body R is the tangential direction at that position of the curve formed by the recording paper P on the side surface of the roll body R.

[0030] Figure 4 illustrates the relationship between the amount of recording paper P pulled from the roll R and the rotation speed of the roll R. The roll R1 shown in Figure 4 represents an example of the roll R when there is a large amount of recording paper P remaining. In Figure 4, the roll R when there is a large amount of recording paper P remaining is indicated by "Roll paper remaining: large". On the other hand, the roll R2 shown in Figure 4 represents an example of the roll R when there is a small amount of recording paper P remaining. In Figure 4, the roll R when there is a small amount of recording paper P remaining is indicated by "Roll paper remaining: small". That is, the roll R1 shown in Figure 4 changes to the roll R2 as the recording paper P is pulled out. Furthermore, the detection surface DM shown in Figure 4 represents an example of a detection surface. However, in Figure 4, the detection surface DM is represented as a rectangular area.

[0031] Arrow A1 in Figure 4 indicates the magnitude of the rotational speed of the roll body R1 at the position furthest from the rotation axis of the roll body R1, depending on the length of arrow A1. On the other hand, arrow A2 in Figure 4 indicates the magnitude of the rotational speed of the roll body R1 at the detection surface DM where light IL is irradiated on the side surface of the roll body R1. By comparing arrows A1 and A2, it can be seen that when there is a large amount of recording paper P remaining, as in the case of the roll body R1, the magnitude of the rotational speed of the roll body R1 at the detection surface DM where light IL is irradiated on the side surface of the roll body R1 is smaller than the magnitude of the rotational speed of the roll body R1 at the position furthest from the rotation axis of the roll body R1. Furthermore, this magnitude relationship holds true not only for rotational speed but also for tangential speed.

[0032] Furthermore, arrow A3 in Figure 4 indicates the magnitude of the rotational speed of roll body R2 at the position furthest from the rotation axis of roll body R2, depending on the length of arrow A3. By comparing arrows A2 and A3, it can be seen that when the amount of recording paper P remaining decreases, as in roll body R2, the magnitude of the rotational speed of roll body R2 on the detection surface DM becomes greater than the magnitude of the rotational speed of roll body R1 on the detection surface DM. And this relationship of magnitude holds true not only for rotational speed but also for tangential speed.

[0033] As described above, in the printing apparatus 1 of this embodiment, which employs a pivot mechanism 40 that supports the roll body R, the rotational speed of the roll body R changes as the recording paper P is pulled out from the roll body R. The rotational speed of the roll body R increases monotonically as the recording paper P is pulled out. This means that the tangential speed of the roll body R on the detection surface DM can be correlated one-to-one with the remaining amount of recording paper P. This is because the tangential speed of the roll body R on the detection surface DM is proportional to the rotational speed of the roll body R on the detection surface DM. Note that the tangential speed of the roll body R on the detection surface DM is the tangential speed of the curve formed by the recording paper P on the detection surface DM.

[0034] Figure 5 illustrates how the tangential velocity of the roll R on the detection surface DM increases monotonically as the recording paper P is pulled out. The horizontal axis of the graph in Figure 5 represents the diameter of the roll R. Here, the diameter of the roll R corresponds one-to-one with the remaining amount of recording paper P, and is therefore one of the indicators of the remaining amount of recording paper P. The vertical axis of the graph represents the tangential velocity of the roll R on the detection surface DM. In Figure 5, the detection surface DM is referred to as the "sensing area." Also in Figure 5, the tangential velocity of the roll R on the detection surface DM is referred to as the "sensing area velocity."

[0035] The curve F plotted in the graph shown in Figure 5 indicates that the tangential velocity of the roll body R on the detection surface DM increases monotonically as the amount of recording paper P decreases. For example, the diameter of the roll body R at point P1 on curve F corresponds to the diameter of roll body R3 shown in Figure 5. Roll body R3 is an example of roll body R with a diameter of approximately 180 mm. Also, for example, the diameter of the roll body R at point P2 on curve F corresponds to the diameter of roll body R4 shown in Figure 5. Roll body R4 is an example of roll body R with a diameter of approximately 130 mm. Also, for example, the diameter of the roll body R at point P3 on curve F corresponds to the diameter of roll body R5 shown in Figure 5. Roll body R5 is an example of roll body R with a diameter of approximately 85 mm. Thus, since the tangential velocity of the roll body R on the detection surface DM increases as the amount of recording paper P decreases, it can be correlated one-to-one with the amount of recording paper P.

[0036] Therefore, the printing device 1 detects the speed of the roll body R in a predetermined direction as the tangential direction on the detection surface DM, and detects the remaining amount of recording paper P based on the detected speed. This allows the printing device 1 to accurately determine the remaining amount of recording paper P.

[0037] Returning to Figure 2, the transport roller 12 is located on the -Y side of the opening / closing door 3 and on the -Z side of the transport path through which the recording paper P is transported. The print head 200 is positioned opposite the transport roller 12 via the recording paper P. The transport roller 12 and the print head 200 grip the recording paper P as it is pulled out from the roll R. The transport roller 12 rotates due to the rotational drive of a motor (not shown). The rotation of the transport roller 12 transports the recording paper P gripped by the transport roller 12 and the print head 200. As a result, the recording paper P is pulled out from the roll R. The pulled-out recording paper P is then transported toward the print head 200.

[0038] An encoder 16 is provided on the transport roller 12. The encoder 16 includes a disc 17 and a photosensor 18. The disc 17 has a number of slits formed on its periphery and is fixed to the transport roller 12 such that its central axis coincides with the rotation axis of the transport roller 12. That is, the disc 17 rotates in conjunction with the rotation of the transport roller 12. The photosensor 18 is positioned opposite the periphery of the disc 17. At this time, the photosensor 18 is fixed in a location where its position does not change even when the transport roller 12 rotates, for example, by being fixed to the main body case 2. The photosensor 18 binaryly acquires the change in light intensity that occurs when light passes through each slit on the periphery of the disc 17 as the transport roller 12 rotates. The photosensor 18 then generates a pulse signal corresponding to the acquired change in light intensity. The encoder 16 outputs the pulse signal generated by the photosensor 18.

[0039] The print head 200 applies heat to the recording paper P held between the transport roller 12 at a timing synchronized with the pulse signal output by the encoder 16. In other words, the print head 200 performs printing by applying heat to the recording paper P as it is pulled out from the roll body R by rotation, at a timing corresponding to the transport of the recording paper P by the transport roller 12. As a result, the desired image is printed on the recording paper P.

[0040] The movable blade 14a and the fixed blade 14b are located along the transport path of the recording paper P transported by the transport roller 12, closer to the discharge port 4 than the print head 200. Specifically, the movable blade 14a is located +Y side of the transport roller 12 and the print head 200, and -Z side of the recording paper P transported by the transport roller 12. The fixed blade 14b is located +Y side of the transport roller 12 and the print head 200, and +Z side of the recording paper P transported by the transport roller 12. When the movable blade 14a moves to the +Z side along the Z axis, the recording paper P is sandwiched between the movable blade 14a and the fixed blade 14b and cut. At this time, the movable blade 14a and the fixed blade 14b may perform a partial cut, leaving a portion of the recording paper P uncut, or a full cut, completely cutting the recording paper P. The recording paper P cut by the movable blade 14a and the fixed blade 14b is then discharged from the discharge port 4.

[0041] The paper detection sensor 15 is located near the output port 4 and detects the presence or absence of recording paper P in the vicinity of the output port 4. For example, if the paper detection sensor 15 detects that recording paper P is still present near the output port 4 even after a predetermined time has elapsed since the completion of the printing process, it notifies the user by displaying on the notification unit 5 that the recording paper P has not been cut off and remains.

[0042] The opening / closing sensor 19 is installed near the opening / closing door 3 and detects the opening and closing of the door 3. The opening / closing sensor 19 may be, for example, a mechanical switch that turns on or off in conjunction with the opening and closing of the door 3, or it may be a photosensor whose amount of light received changes binary in conjunction with the opening and closing of the door 3. When the opening / closing sensor 19 detects that the door 3 is open, the printing device 1 notifies the user via the notification unit 5 that the door 3 is open. At this time, the print head 200 may stop executing the printing process.

[0043] The media remaining amount sensor 20 is positioned in a location on the side surface of the roll body R that allows light IL to be irradiated at a predetermined position near the recording paper P stored in the media storage section 30. The media remaining amount sensor 20 detects the amount of horizontal and vertical movement of the roll body R on the detection surface DM on the side surface of the roll body R stored in the media storage section 30 that is irradiated with light IL. Based on the detected amount of movement, the media remaining amount sensor 20 detects the tangential velocity of the roll body R on the detection surface DM.

[0044] For example, in the examples shown in Figures 4 and 5, the detection surface DM is located directly below the rotation axis of the roll body R. In this case, the tangential direction of the roll body R at the detection surface DM is the horizontal direction. Therefore, in this case, the media remaining amount sensor 20 detects the amount of horizontal movement of the roll body R at the detection surface DM and, based on the detected amount of movement, detects the tangential velocity of the roll body R at the detection surface DM. The method for detecting the tangential velocity of the roll body R at the detection surface DM based on the amount of movement may be a known method or a method to be developed in the future.

[0045] Furthermore, for example, if the detection surface DM is located directly beside the rotation axis of the roll body R, the tangential direction of the roll body R on the detection surface DM is the vertical direction. In this case, the media remaining amount sensor 20 detects the amount of vertical movement of the roll body R on the detection surface DM and, based on the detected amount of movement, detects the tangential velocity of the roll body R on the detection surface DM. This is because, in this case, the roll body R does not move horizontally on the detection surface DM. The method for detecting the tangential velocity of the roll body R on the detection surface DM based on the amount of movement may be a known method or a method to be developed in the future.

[0046] Furthermore, for example, if the detection surface DM is located diagonally to the rotation axis of the roll body R, the tangential direction of the roll body R on the detection surface DM is a direction that intersects both the horizontal and vertical directions. In this case, the media remaining amount sensor 20 detects the amount of movement of the roll body R in both the horizontal and vertical directions on the detection surface DM, and detects the tangential velocity of the roll body R on the detection surface DM based on the detected amount of movement. This is because, in this case, the roll body R moves in both the horizontal and vertical directions on the detection surface DM. The method for detecting the tangential velocity of the roll body R on the detection surface DM based on the amount of movement may be a known method or a method to be developed in the future.

[0047] The media remaining amount sensor 20 detects the tangential speed of the roll body R on the detection surface DM, and then, based on the detected speed, detects the remaining amount of recording paper P contained in the roll body R stored in the media storage unit 30. Details of this media remaining amount sensor 20 will be described later.

[0048] <Functional Configuration of Printing Devices> Next, the functional configuration of the printing device 1 will be described. Figure 6 is a diagram showing an example of the functional configuration of the printing device 1. As mentioned above, the printing device 1 of this embodiment is a thermal printer that prints on a medium by applying heat to a desired position on the recording paper P, such as thermal paper. As shown in Figure 6, the printing device 1 includes a main control circuit 100, a power input IF 110, a power generation circuit 120, a printing unit 150, an external IF 160, a power switch 6, a notification unit 5, a paper detection sensor 15, an open / close sensor 19, and a remaining amount detection circuit 170.

[0049] The printing device 1 is supplied with a DC voltage signal Vd via the power input IF110. The voltage signal Vd is input to the power generation circuit 120. The power generation circuit 120 converts the input voltage signal Vd into a voltage value used in the various configurations of the printing device 1 by boosting or stepping down its voltage. The power generation circuit 120 then outputs a constant voltage signal Vdd with the converted voltage value to the corresponding configuration. Such a power generation circuit 120 is configured to include a DC (Direct Current)-DC converter. Here, the power generation circuit 120 may generate a constant voltage signal Vdd with a voltage value corresponding to each of the various configurations of the printing device 1 and output it to the corresponding configuration. That is, the power generation circuit 120 may output multiple voltage signals Vdd with different voltage values, and may include multiple DC-DC converters that output multiple voltage signals Vdd.

[0050] The power switch 6 generates a power signal Pw requesting the start of the printer 1 or a power signal Pw requesting its stop, based on the user's operation, and outputs it to the main control circuit 100.

[0051] The main control circuit 100 receives the voltage signal Vdd output by the power generation circuit 120 and the power signal Pw output by the power switch 6. The main control circuit 100 starts operating when the power switch 6 outputs the power signal Pw, which requests the start of the printing device 1, while the voltage signal Vdd is being input.

[0052] Furthermore, the main control circuit 100 receives a communication information signal CS via the external IF 160 for communicating with an external device located outside the printing device 1. The main control circuit 100 outputs signals to control various configurations of the printing device 1 according to the input communication information signal CS. The main control circuit 100 also generates a communication information signal CS for controlling the operation of the external device and outputs it to the external device via the external IF 160. In other words, the main control circuit 100 and the external device located outside the printing device 1 are connected via the external IF 160 to enable bidirectional communication. Here, the external IF 160 may be a wireless communication module that performs wireless communication with the external device according to the communication information signal CS and converts the signal to a signal compliant with a communication standard such as Wi-Fi (registered trademark) or Bluetooth (registered trademark), or it may be a wired communication module that performs wired communication with the external device according to the communication information signal CS and converts the signal to a signal compliant with a communication standard such as USB (Universal Serial Bus) communication. Furthermore, external devices such as a personal computer, tablet terminal, or POS (Point of Sale) terminal can be used to initiate printing on the printing device 1.

[0053] When the main control circuit 100 receives a communication information signal CS for executing a printing process from an external device via the external IF 160, it outputs a print control signal Pc to the printing unit 150 to print the information corresponding to the communication information signal CS.

[0054] The printing unit 150 receives a printing control signal Pc output by the main control circuit 100 and a voltage signal Vdd output by the power supply generation circuit 120. The printing unit 150 uses the voltage signal Vdd as the drive voltage and performs a printing process to print information corresponding to the printing control signal Pc onto the recording paper P.

[0055] The printing unit 150 includes a head control circuit 220, a transport control circuit 230, a cutting control circuit 240, and a print head 200. The print head 200 also includes a plurality of heating elements 210.

[0056] The transport control circuit 230 controls the transport of the recording paper P in accordance with the print control signal Pc input from the main control circuit 100. Specifically, the transport control circuit 230 controls the rotation of the transport roller 12 by controlling the rotational drive of a motor (not shown) in accordance with the input print control signal Pc. This causes the recording paper P to be pulled out from the roll R.

[0057] The cutting control circuit 240 cuts the recording paper P to a predetermined size in accordance with the print control signal Pc input from the main control circuit 100. Specifically, the transport control circuit 230 moves the movable blade 14a to -Z shown in Figure 2 at a timing defined by the input print control signal Pc. As a result, the recording paper P, which is transported by the rotation of the transport roller 12, is sandwiched between the movable blade 14a and the fixed blade 14b. Consequently, the recording paper P is cut to a predetermined size. Here, the cutting control circuit 240 may also control the timing of moving the movable blade 14a in accordance with a pulse signal output by the encoder 16, in addition to the input print control signal Pc.

[0058] The head control circuit 220 outputs a drive signal Drv corresponding to each of the multiple heating elements 210 of the print head 200, in response to the print control signal Pc input from the main control circuit 100. This controls the driving state of each heating element 210, specifically whether or not each heating element 210 generates heat. Specifically, the head control circuit 220 generates a drive signal Drv corresponding to each of the multiple heating elements 210 in response to the input print control signal Pc. The head control circuit 220 then outputs the drive signal Drv to each of the corresponding heating elements 210 at a timing corresponding to the pulse signal output by the encoder 16.

[0059] In the printing unit 150 configured as described above, the multiple heating elements 210 of the print head 200 are arranged in parallel along the X-axis shown in Figure 2, in a direction perpendicular to the transport direction in which the recording paper P is transported. The transport control circuit 230 controls the transport of the recording paper P based on the print control signal Pc, and the head control circuit 220 outputs a drive signal Drv corresponding to each of the multiple heating elements 210 based on the print control signal Pc. That is, the head control circuit 220 outputs a drive signal Drv corresponding to each of the multiple heating elements 210 at a timing synchronized with the transport of the recording paper P. As a result, heat generated by the heating elements 210 is applied to the desired position on the transported recording paper P. As a result, characters, images, etc. containing the desired information are formed on the recording paper P. Subsequently, the recording paper P on which characters and images containing the desired information are formed is cut to a predetermined size by the cutting control circuit 240, and the recording paper P of the predetermined size with the desired information printed on it is discharged from the discharge port 4.

[0060] Furthermore, the main control circuit 100 generates a notification information signal Cd corresponding to the status of the printing device 1 and outputs it to the notification unit 5. The notification unit 5 notifies the user of the printing device 1 of the information corresponding to the input notification information signal Cd. This allows the user to understand the status of the printing device 1.

[0061] The paper detection sensor 15 detects the presence or absence of recording paper P near the output port 4. After the printing process in the printing unit 150 is completed, if the recording paper P is still located near the output port 4, the paper detection sensor 15 generates a remaining information signal Ps to notify the user that the recording paper P has been left behind, and outputs it to the main control circuit 100. The main control circuit 100 generates a notification information signal Cd corresponding to the input remaining information signal Ps and outputs it to the notification unit 5. This notifies the user that the recording paper P has been left behind.

[0062] The opening / closing sensor 19 detects whether the opening / closing door 3 is open or not. The opening / closing sensor 19 then generates an opening / closing information signal Os according to whether the opening / closing door 3 is open or not, and outputs it to the main control circuit 100. If the main control circuit 100 determines that the opening / closing door 3 is open based on the opening / closing information signal Os, it generates a print control signal Pc to stop the execution of the printing process in the printing unit 150 and outputs it to the printing unit 150. At the same time, it generates a notification information signal Cd to notify the user that the opening / closing door 3 is open and outputs it to the notification unit 5. In this way, the user is notified of a warning that the opening / closing door 3 is open.

[0063] The remaining amount detection circuit 170 includes the media remaining amount sensor 20 described above. The remaining amount detection circuit 170 uses the media remaining amount sensor 20 to detect the remaining amount of recording paper P contained in the roll body R stored in the media storage unit 30. The remaining amount detection circuit 170 then generates a remaining amount information signal Rs corresponding to the remaining amount of recording paper P contained in the roll body R stored in the media storage unit 30 and outputs it to the main control circuit 100.

[0064] The main control circuit 100 generates a notification information signal Cd corresponding to the input remaining amount information signal Rs and outputs it to the notification unit 5. This notifies the user of the remaining amount of recording paper P contained in the roll R stored in the media storage unit 30. Here, the main control circuit 100 may generate a notification information signal Cd to notify the remaining amount of recording paper P contained in the roll R stored in the media storage unit 30 and output it to the notification unit 5, or it may generate a notification information signal Cd to notify whether the remaining amount of recording paper P contained in the roll R stored in the media storage unit 30 is sufficient, insufficient, or has run out of recording paper P and output it to the notification unit 5.

[0065] <Functional configuration of the remaining battery detection circuit> Here, a specific example of the configuration of the remaining amount detection circuit 170, which detects the remaining amount of recording paper P contained in the roll body R housed in the media storage unit 30, will be described. Figure 7 is a diagram showing an example of the configuration of the remaining amount detection circuit 170. As shown in Figure 7, the remaining amount detection circuit 170 has a media remaining amount sensor 20 and a determination circuit 175. The media remaining amount sensor 20 also has a light-emitting element 21, a light-receiving unit 22, and a DSP (Digital Signal Processor) 23. Here, the media remaining amount sensor 20 may be configured as a single integrated circuit device including the light-emitting element 21, the light-receiving unit 22, and the DSP 23. The determination circuit 175 may be configured as a single integrated circuit device individually, as a single integrated circuit device together with the media remaining amount sensor 20, or as a single integrated circuit device together with the main control circuit 100.

[0066] The light-emitting element 21 includes a vertical cavity surface-emitting laser (VCSEL) and emits optical light (IL) as a laser with a peak at a specific wavelength such as 850 nm. The optical light emitted by this light-emitting element 21 is irradiated onto one side of the roll body R.

[0067] The light-receiving unit 22 includes a plurality of light-receiving elements 24. In the light-receiving unit 22, the plurality of light-receiving elements 24 are arranged in multiple rows and multiple columns. At this time, the plurality of light-receiving elements 24 may be arranged in a square grid, or in a triangular grid, for example. Each of the plurality of light-receiving elements 24 included in the light-receiving unit 22 detects the reflected light RL that the light IL has reflected off the detection surface DM. The light-receiving unit 22 then generates a detection light information signal LR that includes detection information DI corresponding to the reflected light RL detected by each of the plurality of light-receiving elements 24, and outputs it to the DSP 23. Here, the detection information DI corresponding to the reflected light RL detected by the light-receiving element 24 may be information on the intensity of the reflected light RL, information on the wavelength of the reflected light RL, or information on the intensity of a specific wavelength included in the reflected light RL.

[0068] The DSP23 acquires detection information DI detected by each of the multiple photodetectors 24 based on the input detection light information signal LR. The DSP23 then calculates image information corresponding to the reflected light RL reflected from the side surface of the roll body R by arranging the acquired detection information DI detected by each of the multiple photodetectors 24 according to the arrangement of the multiple photodetectors 24 in the light receiving unit 22. In other words, the DSP23 calculates image information in which the detection information DI detected by each of the multiple photodetectors 24 is arranged as pixel information. At this time, the image corresponding to the image information calculated by the DSP23 will have speckles such as interference fringes and spot patterns caused by interference, diffraction, etc., which are generated in response to the light emitted by the light-emitting element 21.

[0069] The DSP23 calculates image information corresponding to the reflected light RL detected by each of the multiple photodetectors 24 when light IL is irradiated onto the side of the roll body R at any time t1, and then calculates image information corresponding to the reflected light RL detected by each of the multiple photodetectors 24 when light IL is irradiated onto the side of the roll body R at any time t2 after time t1. Then, the DSP23 calculates the amount of horizontal and vertical movement of the roll body R on the detection surface DM by comparing the image information calculated at time t1 with the image information calculated at time t2. For the sake of explanation, the amount of horizontal movement of the roll body R will be referred to as movement amount dtx, and the amount of vertical movement of the roll body R will be referred to as movement amount dty. Based on at least one of the calculated movement amounts dtx and dty, the DSP23 calculates the velocity in a predetermined direction as the tangential direction of the roll body R on the detection surface DM. The function for calculating the speed based on at least one of the displacement amounts dtx and dty may be performed by a component other than the DSP23 in the remaining amount detection circuit 170, or by another component such as the main control circuit 100. Furthermore, the detection methods for the displacement amounts dtx and dty may be known methods or methods to be developed in the future. The DSP23 outputs the calculated speed to the determination circuit 175.

[0070] The media remaining amount sensor 20 configured as described above irradiates the roll body R, which is the test subject, with light IL output by the light-emitting element 21. The media remaining amount sensor 20 also detects the reflected light RL reflected from the roll body R, thereby detecting at least one of the information on the detection surface DM and the speckle contained in the reflected light RL. Based on the detection result, the media remaining amount sensor 20 detects the tangential velocity at the detection surface DM of the roll body R. An optical tracking sensor can be used as such a media remaining amount sensor 20. For the sake of explanation below, the velocity detected by the media remaining amount sensor 20 will be referred to as the tangential velocity.

[0071] Returning to Figure 7, the tangential velocity output by the DSP 23 of the media remaining amount sensor 20 is input to the determination circuit 175. Based on the input tangential velocity, the determination circuit 175 determines the remaining amount of recording paper P contained in the roll R. The determination circuit 175 then generates a remaining amount information signal Rs corresponding to the determined remaining amount of recording paper P contained in the roll R. This remaining amount information signal Rs generated by the determination circuit 175 is output from the remaining amount detection circuit 170.

[0072] Here, the remaining amount information signal Rs, which corresponds to the information on the remaining amount of recording paper P contained in the roll body R, may be the absolute value of the remaining amount of recording paper P contained in the roll body R calculated based on the tangential speed, or it may be information indicating that there is sufficient remaining amount of recording paper P contained in the roll body R contained in the media storage unit 30, obtained by comparing the tangential speed with a predetermined threshold, information indicating that there is only a small amount of recording paper P remaining in the roll body R contained in the media storage unit 30, or information indicating that there is no more recording paper P contained in the roll body R contained in the media storage unit 30. Furthermore, the remaining amount information signal Rs may be a combination of some of these pieces of information. In addition, the determination circuit 175 may determine the remaining amount of recording paper P contained in the roll body R based on the tangential speed and generate a remaining amount information signal Rs according to the determination result.

[0073] The determination circuit 175 may determine the remaining amount of recording paper P by using a table that associates the tangential speed with the remaining amount of recording paper P for each tangential speed, or by using a calculation formula that shows the proportional relationship between the tangential speed and the remaining amount of recording paper P, or by using another method based on the correspondence between the tangential speed and the remaining amount of recording paper P.

[0074] The determination circuit 175 can determine the remaining amount of recording paper P wound on the roll R, even when the media remaining amount sensor 20 is fixed at different positions and angles on the printing device 1 and the main body case 2, by using appropriate calculation formulas, tables, etc., according to the fixed position and fixed angle of the media remaining amount sensor 20.

[0075] <Recommended positions on the side of the roll body where light should be irradiated as a detection surface> The following describes the recommended positions on the side of the roll body R where light is irradiated as the detection surface DM, referring to Figure 8. Figure 8 is a diagram illustrating the recommended positions on the side of the roll body R where light is irradiated as the detection surface DM.

[0076] Figure 8 shows the side view of the roll body R as seen from the +X side towards the -X side. In other words, in the example shown in Figure 8, the detection surface DM is a part of the side view of the roll body R in that case. The positions on this side view where it is recommended to irradiate light as the detection surface DM are the positions included within each of the regions RN1 to RN3 shown in Figure 8. Here, the φ shown in Figure 8 e This indicates the outer diameter of the core material C. Also, the φ shown in Figure 8 i This indicates the inner diameter of the core material C. Also, the φ shown in Figure 8 s This indicates the diameter of the detection surface DM.

[0077] Region RN1 is the outer diameter φ of the core material C. e From a circular region whose diameter is the sum of the detection surface DM and twice its diameter, the outer diameter φ of the core material C is measured. eThis is the area that remains after subtracting a circular area with a diameter of . When area RN1 is the detection surface DM, the printing device 1 can estimate the remaining amount of recording paper P until the remaining amount of recording paper P is almost 0. This is because area RN1 is the area that is in contact with the outer circumference of the core material C. Area RN1 is an example of an outer area determined according to the outer diameter of the core material.

[0078] Region RN2 is the entire side surface of the core material C when viewed from the +X side towards the -X side. When region RN1 is the detection surface DM, the printing device 1 can reliably estimate the remaining amount of recording paper P until the remaining amount of recording paper P reaches zero. This is because the recording paper P is wound around the core material C.

[0079] Region RN3 is the inner diameter φ of the core material C. i A circular region whose diameter is obtained by subtracting twice the diameter of the detection surface DM from the inner diameter φ of the core material C. i This is the area that remains after subtracting it from a circular area with a diameter of . When area RN3 is the detection surface DM, the printing device 1 can reliably estimate the remaining amount of recording paper P until the remaining amount of recording paper P becomes 0. This is because area RN3 is the area that is in contact with the inner circumference of the core material C. However, area RN3 is, for example, a part of the shaft 41. Therefore, area RN3 does not necessarily exist. Area RN3 is an example of an inner area determined according to the inner diameter of the core material.

[0080] By designating a portion of any of the regions RN1 to RN3 as the detection surface DM, the printing device 1 can accurately determine the remaining amount of recording paper P until the remaining amount of recording paper P is nearly 0 or completely 0. The detection surface DM may be a region spanning region RN1 and region RN2, a region spanning region RN2 and region RN3, or a region spanning all of regions RN1 to RN3.

[0081] Furthermore, if it is not necessary to determine the remaining amount of recording paper P until the remaining amount of recording paper P is nearly 0 or completely 0, the detection surface DM may be located on any side of the roll body R when viewed from the +X side towards the -X side.

[0082] <Process by which the printing device determines the remaining amount of recording paper> The following describes the process by which the printing device 1 determines the remaining amount of recording paper P, with reference to Figure 9. Figure 9 is a diagram showing an example of the process flow for determining the remaining amount of recording paper P by the printing device 1. For example, each time the printing device 1 starts printing an image onto the recording paper P, it performs the process shown in the flowchart in Figure 9.

[0083] When printing an image onto the recording paper P begins, the main control circuit 100 waits until the rotation speed of the roll R stabilizes (step S110). For example, in step S110, the main control circuit 100 determines that the rotation speed has stabilized when the transport speed of the recording paper P becomes approximately constant. Alternatively, in step S110, the main control circuit 100 determines that the rotation speed is not stable if the transport speed of the recording paper P is not constant. The main control circuit 100 may also be configured to determine whether or not the rotation speed of the roll R has stabilized by other means.

[0084] When the main control circuit 100 determines that the rotational speed of the roll body R has stabilized (step S110-YES), it controls the remaining amount detection circuit 170 and starts detecting the tangential velocity using the remaining amount sensor 20 (step S120).

[0085] Next, the main control circuit 100 waits until the printing of the image onto the recording paper P is complete (step S130). The method by which the main control circuit 100 determines whether the printing is complete in step S130 may be a known method or a method to be developed in the future.

[0086] If the main control circuit 100 determines that printing of the image onto the recording paper P is complete (step S130-YES), it controls the remaining amount detection circuit 170 to terminate the detection of the tangential velocity by the remaining amount sensor 20, which was started in step S120. The main control circuit 100 then determines whether the detection was successful or not (step S140). The method for determining whether the detection was successful or not in step S140 may be a known method or a method to be developed in the future.

[0087] If the main control circuit 100 determines that it has failed to detect the tangential velocity using the medium remaining amount sensor 20, which was started in step S120 (step S140-NO), it performs error processing for the detection (step S170). Here, the error processing may include, for example, outputting a notification information signal Cd indicating that the detection failed to the notification unit 5 to notify the notification unit 5 of the failure, or outputting information indicating that the detection failed to another device, but is not limited to these, and may include other processing depending on the failure of the detection. After the processing in step S170 is performed, the main control circuit 100 terminates the processing shown in the flowchart in Figure 9.

[0088] On the other hand, if the main control circuit 100 determines that it has succeeded in detecting the tangential speed using the media remaining amount sensor 20, which was started in step S120 (step S140-YES), it controls the determination circuit 175 to determine the remaining amount of recording paper P based on the tangential speed detected by the media remaining amount sensor 20 (step S150). Note that the method for determining the remaining amount based on the tangential speed in step S150 has already been explained, so the explanation is omitted here. Also, as mentioned above, in the printing device 1, the tangential speed and the remaining amount of recording paper P are associated one-to-one. Therefore, if the tangential speed is a certain speed X1, the determination circuit 175 determines that the remaining amount is the remaining amount Y1 associated with speed X1. On the other hand, if the tangential speed is a speed X2 that is faster than speed X1, the determination circuit 175 determines that the remaining amount is the remaining amount Y2, which is less than the remaining amount Y1. However, the remaining amount Y2 is the remaining amount associated with speed X2.

[0089] The main control circuit 100 controls the notification unit 5 and notifies the remaining amount of recording paper P determined by the determination circuit 175 in step S150 as the determination result (step S160), and terminates the process shown in the flowchart in Figure 9.

[0090] As described above, the printing device 1 determines the remaining amount of recording paper P based on the detection result of the media remaining amount sensor 20. However, in the printing device 1, during the period in which the media remaining amount sensor 20 is detecting, the relative position of the media remaining amount sensor 20 with respect to the core material C is substantially constant, except for slight deviations due to vibration, etc. This prevents the printing device 1 from changing the position of the media remaining amount sensor 20 with respect to the roll body R, and eliminates the need to provide the media remaining amount sensor 20 on the pivot mechanism 40. As a result, the printing device 1 can accurately determine the remaining amount of recording paper P, and the design flexibility of the pivot mechanism 40 can be improved.

[0091] <Modified examples of embodiments> The following describes modifications of the embodiment. In the modified embodiment, the printing apparatus 1 includes a lens 50 located between the media remaining amount sensor 20 and the roll body R, as shown in Figure 10. Figure 10 is a diagram showing an example of the configuration of the lens 50 included in the printing apparatus 1 according to the modified embodiment.

[0092] The lens 50 covers at least part or all of the light-emitting element 21 and the light-receiving element 22 of the media remaining amount sensor 20, thereby suppressing malfunctions of the media remaining amount sensor 20 caused by the adhesion of paper dust or the like to at least one of the light-emitting element 21 and the light-receiving element 22. In other words, by providing the lens 50, the printing apparatus 1 can improve the paper dust resistance of the media remaining amount sensor 20. Furthermore, by providing the lens 50, the printing apparatus 1 can shorten the focal length of the media remaining amount sensor 20. This leads to a simplification of the structure of the printing apparatus 1, which is useful. However, when the printing apparatus 1 is equipped with the lens 50, the depth of field of the media remaining amount sensor 20 becomes shallower. This can lead to a deterioration in the accuracy of tangential velocity detection by the media remaining amount sensor 20 if the relative position of the roll body R with respect to the media remaining amount sensor 20 changes. However, in the printing apparatus 1, during the period in which the media remaining amount sensor 20 detects the tangential velocity, the relative position of the media remaining amount sensor 20 with respect to the core material C of the roll body R is approximately constant, except for slight deviations due to vibration, etc. This is because the roll body R is supported by the pivot mechanism 40. As a result, unlike printing apparatuses that employ a drop-in method, the printing apparatus 1 can suppress deterioration in the accuracy of tangential velocity detection by the media remaining amount sensor 20. In other words, the printing apparatus 1 can improve the paper dust resistance of the media remaining amount sensor 20 with the lens 50 while suppressing deterioration in the accuracy of tangential velocity detection by the media remaining amount sensor 20.

[0093] In the example shown in Figure 10, the lens 50 covers the entire surface of the lens of the media remaining amount sensor 20 that faces the roll body R. Here, the lens refers to the lenses of the light-emitting element 21 and the light-receiving element 22 of the media remaining amount sensor 20. As a result, the printing apparatus 1 can more reliably improve the paper dust resistance of the media remaining amount sensor 20.

[0094] As described above, the printing apparatus 1 according to this embodiment includes a media storage section 30 that houses a roll body R containing recording paper P wound in a roll shape around a core material C, a shaft support mechanism 40 having a shaft 41 inserted through a cavity H in the core material C and supporting the roll body R through which the shaft 41 is inserted within the media storage section 30, a print head 200 that prints on the recording paper P pulled out from the roll body R by rotation, and a remaining amount detection circuit 170 that detects the remaining amount of recording paper P stored in the media storage section 30. The remaining amount detection circuit 170 includes a media remaining amount sensor 20 that irradiates light IL onto a detection surface DM of the roll body R that intersects with the rotation axis of the roll body R and detects the reflected light IL, and a determination circuit 175 that determines the remaining amount of recording paper P based on the detection result of the media remaining amount sensor 20. However, during the period in which the media remaining amount sensor 20 is performing detection, the relative position of the media remaining amount sensor 20 with respect to the core material C is substantially constant. As a result, the printing device 1 can suppress changes in the position of the media remaining amount sensor 20 relative to the roll body R, and it is no longer necessary to install the media remaining amount sensor 20 on the pivot mechanism 40. Consequently, the printing device 1 can accurately determine the remaining amount of recording paper P, and the design flexibility of the pivot mechanism 40 can be improved.

[0095] <Note> [1] A printing apparatus comprising: a media storage section that houses a roll containing recording paper wound in a roll around a cylindrical core material having a hollow in its center; a shaft support mechanism having a shaft inserted through the hollow of the core material and supporting the roll with the shaft inserted through it within the media storage section; a print head that prints on the recording paper pulled out from the roll by rotation; and a remaining amount detection circuit that detects the remaining amount of recording paper stored in the media storage section, wherein the remaining amount detection circuit comprises an optical tracking sensor that irradiates light onto a detection surface of the roll intersecting the rotation axis of the roll and detects the reflected light, and a determination circuit that determines the remaining amount of recording paper based on the detection result of the optical tracking sensor, wherein the relative position of the optical tracking sensor with respect to the core material is substantially constant during the period in which the optical tracking sensor is performing detection. [2] The printing apparatus according to [1], wherein the optical tracking sensor detects the speed of the roll body moving in a predetermined direction relative to the optical tracking sensor, and the determination circuit determines the remaining amount based on the speed detected by the optical tracking sensor. [3] The printing apparatus according to [2], wherein the optical tracking sensor detects the speed based on at least one of the amount of horizontal movement of the roll body on the detection surface and the amount of vertical movement of the roll body on the detection surface. [4] The printing apparatus according to [2] or [3], wherein the determination circuit determines that the remaining amount is the first remaining amount when the speed is the first speed, and determines that the remaining amount is the second remaining amount which is less than the first remaining amount when the speed is the second speed which is faster than the first speed. [5] The detection surface is a part of the surface of the roll body that intersects with the rotation axis of the roll body, and is a surface included in either an inner region determined according to the inner diameter of the core material or an outer region determined according to the outer diameter of the core material, according to any one of the printing apparatuses described in [1] to [4]. [6] A printing apparatus according to any one of [1] to [5], comprising a notification unit for notifying the determination result of the determination circuit. [7] A printing apparatus according to any one of [1] to [6], comprising a lens positioned between the optical tracking sensor and the roll body. [8] The printing apparatus according to [7], wherein the lens covers the entire surface of the lens of the optical tracking sensor that faces the roll body.

[0096] Although embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may be modified, substituted, deleted, etc., as long as it does not depart from the spirit of this invention.

[0097] Furthermore, a program to realize the function of any component in the device described above may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed. Here, the device is, for example, a printing device 1. The term "computer system" here includes hardware such as an OS (Operating System) and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, CD (Compact Disk)-ROMs, and storage devices such as hard disks built into a computer system. In addition, the term "computer-readable recording medium" also includes volatile memory within a computer system that acts as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, which retains the program for a certain period of time.

[0098] Furthermore, the above program may be transmitted from a computer system that stores the program in a memory device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" used to transmit the program refers to a medium that has the function of transmitting information, such as a network like the Internet or a communication line like a telephone line. Furthermore, the above program may be intended to implement some of the functions described above. In addition, the above program may be one that can implement the functions described above in combination with a program already recorded in the computer system, a so-called differential file or differential program. [Explanation of Symbols]

[0099] 1…Printing device, 2…Main case, 3…Opening / closing door, 4…Discharge port, 5…Notification unit, 6…Power switch, 7…Opening / closing lever, 8…Hinge unit, 12…Conveyor roller, 14a…Movable blade, 14b…Fixed blade, 15…Paper detection sensor, 16…Encoder, 17…Disc, 18…Photosensor, 19…Opening / closing sensor, 20…Media remaining amount sensor, 21…Light-emitting element, 22…Light-receiving unit, 24…Light-receiving element, 30…Media storage unit, 40…Axis support mechanism, 41…Axis, 42…Structure, 50…Lens, 100…Main control circuit, 120…Power generation circuit, 150…Printing unit, 170…Remaining amount detection circuit, 175…Determination circuit, 200…Print head, 210…Heating element, 220…Head control circuit, 230…Conveyor control circuit, 240…Cutting control circuit

Claims

1. A media storage section that houses a roll containing recording paper wound in a roll around a cylindrical core material with a hollow in the center, A shaft support mechanism having a shaft inserted through the cavity of the core material, and supporting the roll body through which the shaft is inserted within the media storage section, A print head that prints on the recording paper pulled out from the roll by rotation, A remaining amount detection circuit for detecting the remaining amount of recording paper stored in the media storage section, Equipped with, The remaining amount detection circuit is, An optical tracking sensor that irradiates light onto a detection surface of the roll body that intersects with the rotation axis of the roll body and detects the reflected light, A determination circuit that determines the remaining amount of recording paper based on the detection result of the optical tracking sensor, It has, During the period in which the optical tracking sensor is performing detection, the relative position of the optical tracking sensor with respect to the core material remains substantially constant. Printing device.

2. The optical tracking sensor detects the speed of the roll body moving in a predetermined direction relative to the optical tracking sensor, The determination circuit determines the remaining amount based on the speed detected by the optical tracking sensor. The printing apparatus according to claim 1.

3. The optical tracking sensor detects the speed based on at least one of the amount of horizontal movement of the roll body on the detection surface and the amount of vertical movement of the roll body on the detection surface. The printing apparatus according to claim 2.

4. The determination circuit determines that if the speed is the first speed, the remaining amount is the first remaining amount, and if the speed is a second speed which is faster than the first speed, it determines that the remaining amount is a second remaining amount which is less than the first remaining amount. The printing apparatus according to claim 2.

5. The detection surface is a part of the surface of the roll body that intersects with the rotation axis of the roll body, and is a surface included in either an inner region determined according to the inner diameter of the core material or an outer region determined according to the outer diameter of the core material. The printing apparatus according to claim 1.

6. The system includes a notification unit that notifies the determination result of the determination circuit. The printing apparatus according to claim 1.

7. The optical tracking sensor and the roll body are provided with a lens located between them. The printing apparatus according to claim 1.

8. The lens covers the entire surface of the optical tracking sensor that faces the roll body. The printing apparatus according to claim 7.

Images