JP7828077B2 - Paper cutting mechanism, printing mechanism, and thermal printer - Google Patents

Description

The present invention relates to a paper cutting mechanism, a printing mechanism, and a thermal printer.

Conventionally, there are known devices that print on recording paper pulled from a roll and then move a cutter blade to cut the recording paper. This type of device is used, for example, to print tickets and receipts. Patent Document 1 discloses a device in which a pair of gears that mesh with a motor's drive gear rotate when the drive gear is rotated, causing the cutter blade to move back and forth.

Japanese Patent Application Laid-Open No. 2008-068340

The technology in Patent Document 1 leaves room for improvement in terms of transmitting high torque driving force to the cutter blade while also achieving compactness.

The present invention was developed in light of these issues, and aims to provide a paper cutting mechanism, printing mechanism, and thermal printer that transmits high torque driving force to the cutter blade and is also advantageous for miniaturization.

One form of the paper cutting mechanism of the present invention is a paper cutting mechanism that advances a cutter blade against paper to cut the paper. It includes a motor, a gear train that transmits power from the motor, a main frame that supports the motor and the gear train, and a movement mechanism that moves the cutter blade forward and backward using the power transmitted by the gear train. The gear train has a planetary gear unit connected to the motor and a bevel gear that meshes with a tip gear provided on the output shaft of the planetary gear unit. The rotation of the tip gear is transmitted to the movement mechanism via the bevel gear, causing the movement mechanism to move the cutter blade.

The movement mechanism may include a first cutter gear to which the rotation of the bevel gear is transmitted, the first cutter gear having a pin formed at a position radially away from the rotation axis of the gear, and a second cutter gear that meshes with the first cutter gear, the second cutter gear having a pin formed at a position radially away from the rotation axis of the gear. The cutter blade may be configured to have openings through which the pins of the first cutter gear and the second cutter gear pass, and to have the first cutter gear and the second cutter gear rotate simultaneously, causing the pins to apply a force to the cutter blade in a direction that moves the cutter blade forward or backward, thereby moving the cutter blade forward or backward.

The system may further include a bracket having a support portion formed thereon that supports the outer periphery of the output shaft of the planetary gear unit, and the support portion may have a cross-sectional shape that includes a portion of a circular arc.

The planetary gear unit may further include an emergency gear arranged opposite the bevel gear and having a bevel gear portion that meshes with the tip gear provided on the output shaft of the planetary gear unit, and the tip gear may be sandwiched between the bevel gear and the emergency gear.

The emergency gear may have a disk-shaped operating portion formed with a diameter larger than that of the bevel gear portion, and at least a portion of the operating portion may protrude outward from the main frame housing the emergency gear so that a user can access the operating portion.

The main frame may have a first surface and a second surface, with the motor, gear train, and movement mechanism arranged on the first surface, and the cutter blade arranged on the second surface.

A printing mechanism according to one embodiment of the present invention includes the paper cutting mechanism described above, a thermal head that prints on the paper, and a platen roller that presses the paper against the thermal head and ejects the paper.

One aspect of the present invention is a thermal printer that includes a paper cutting mechanism that advances a cutter blade against paper to cut it, a thermal head that prints on the paper, a platen roller that sandwiches the paper between the thermal head and the platen roller and feeds the paper, a main frame that has an inner support section and an outer support section that support the paper cutting mechanism, and a holder that holds a roll from which the paper is pulled out. The paper cutting mechanism includes a motor, a gear train that transmits power from the motor, and a movement mechanism that moves the cutter blade back and forth using the power transmitted by the gear train. The motor, gear train, and movement mechanism are located on the inner support section, and the gear train includes a planetary gear unit connected to the motor and a bevel gear that meshes with a tip gear attached to the output shaft of the planetary gear unit. The rotation of the tip gear is transmitted to the movement mechanism via the bevel gear, causing the movement mechanism to move the cutter blade.

The cutter blade may be provided on the outer surface support portion.

This invention provides a paper cutting mechanism, printing mechanism, and thermal printer that transmits high torque driving force to the cutter blade and is also advantageous for miniaturization.

1 is a perspective view showing a thermal printer according to an embodiment of the present invention; FIG. 1 is a block diagram showing the main configuration of a thermal printer. FIG. 2 is a perspective view of a printing mechanism incorporating a paper cutting mechanism. FIG. 2 is a perspective view of the printing mechanism with some of the parts of the printing mechanism omitted. FIG. 2 is a perspective view of the printing mechanism with some of the components of the printing mechanism omitted. FIG. 2 is a block diagram showing the main configuration of a paper cutting mechanism. FIG. 2 is a perspective view showing a motor and a gear train arranged on a main frame. FIG. 8 is a perspective view showing the state of FIG. 7 to which some parts such as an emergency gear and a bracket have been added. FIG. 2 is a front view of the motor, gear train, and the like. FIG. 2 is a perspective view showing a motor, a planetary gear unit, and the like. FIG. 2 is a perspective view illustrating a gear train and a bracket. FIG. 10 is another perspective view illustrating the gear train and the bracket. 3A and 3B are diagrams showing detailed structures of a moving mechanism and a gear train. FIG. 2 is a view of the main frame as seen from the side where the cutter blade is arranged. FIG. 2 is a diagram for explaining an emergency gear and its surrounding structure. 1 is a table showing the results of a cutting performance evaluation test.

Embodiments of the present invention will now be described with reference to the drawings. Figure 1 is a perspective view of a thermal printer according to one embodiment of the present invention. Figure 2 is a block diagram showing the main components of the thermal printer. Figure 3 is a perspective view of a printing mechanism incorporating a paper cutting mechanism. Figure 4 is a perspective view of the printing mechanism with some of its components omitted. Figure 5 is a perspective view of the printing mechanism with some of its components omitted.

In the following description, terms such as up, down, left, right, front and rear are used to indicate the orientation of objects shown in the drawings, but these orientations are not intended to limit the present invention.

As shown in FIG. 1, the thermal printer S1 of this embodiment comprises a printing mechanism 100 and a roll holding member 200. The thermal printer S1 is a device that prints on paper Sh pulled from a roll and cuts the printed paper Sh. The thermal printer S1 is a device that prints on receipts, tickets, etc., for example.

As shown in Figure 2, the printing mechanism 100 has, as its main components, a thermal head 110 for printing on paper, a transport mechanism 120 for transporting paper, a paper cutting mechanism 130 for cutting paper, and a control unit 190. The printing mechanism 100 also has a main frame 101 (Figure 1) on which various parts of the printing mechanism 100 are mounted.

In the thermal printer S1 of this embodiment, as shown in FIG. 1, the roll holding member 200 is provided with a roll holding section 201a that holds a roll of paper (not shown). Paper Sh (also simply referred to as "paper") pulled from the roll is inserted into the paper inlet 105 of the printing mechanism 100, where predetermined information is printed by the printing mechanism 100 and the paper is ejected from the paper ejection section 106. As will be described in detail later, in the printing mechanism 100 of this embodiment, the paper Sh is cut by advancing a cutter blade against it. The paper may be thermal paper, recording paper, or the like.

Note that the roll holding portion 201a of the roll holding member 200 is not limited to the configuration shown in Figure 1, and can be modified in various ways.

As shown in Figure 5, the thermal head 110 extends across the width of the printing mechanism 100 (the same direction as the width of the paper Sh). The thermal head 110 can have a conventionally known configuration used in this type of printing mechanism 100. The thermal head 110 is controlled by the control unit 190 (Figure 2). Specifically, the thermal head 110 prints predetermined information on the paper by causing multiple heating elements (not shown) to generate heat in response to control signals sent by the control unit 190.

As shown in FIG. 4, the transport mechanism 120 has a platen roller 121, a gear train 123, and a motor (not shown). The platen roller 121 is a roller made of an elastic material such as rubber, and has the function of pressing the printing surface of the paper toward the thermal head 110 and ejecting (transporting) the paper. The platen roller 121 is positioned opposite the thermal head 110. The platen roller 121 presses the paper guided along the guide plate 125 toward the thermal head 110.

The gear train 123 is made up of multiple gears and is provided at one end of the central shaft of the platen roller 121. The gear train 123 transmits power from a motor (not shown) that is the drive source for the transport mechanism 120. The power transmitted by the gear train 123 causes the platen roller 121 to rotate, and the paper is transported in accordance with the rotation of the platen roller 121.

In this embodiment, moving the lever L shown in Figure 4 moves a pair of claws 122, allowing the platen roller 121 to be removed from the printing mechanism 100. This structure itself is a well-known technique, so a detailed description will be omitted.

(Paper cutting mechanism 130)
The paper cutting mechanism 130 is a mechanism that cuts paper. Fig. 6 is a block diagram showing the main components of the paper cutting mechanism 130. As shown in Fig. 6, the paper cutting mechanism 130 has a motor M, a gear train 140, a moving mechanism 160, and a cutter blade 131. The motor M, gear train 140, moving mechanism 160, and cutter blade 131 are all supported by the main frame 101.

The gear train 140, which will be described in detail later, includes multiple gears and transmits power from the motor M. The movement mechanism 160 uses the power transmitted by the gear train 140 to move the cutter blade 131 toward and away from the fixed blade 138 (Figure 3).

The detailed structure of the paper cutting mechanism 130 will be described with reference to Figures 7 to 12. Figure 7 is a perspective view showing the motor M and gear train 140 arranged on the main frame 101. Figure 8 is a perspective view showing the state of Figure 7 with the addition of several parts such as an emergency gear and bracket. Figure 9 is a view of the motor M, gear train 140, etc. from the front. Figure 10 is a perspective view showing the motor M, planetary gear unit, etc. Figure 11 is a perspective view illustrating the gear train 140 and bracket 170. Figure 12 is another perspective view illustrating the gear train 140 and bracket 170.

Describing the main frame 101, which is the housing of the paper cutting mechanism 130, the main frame 101 is a member on which various components are arranged, and in this embodiment, as an example, has a generally box-like shape as shown in Figure 7. The main frame 101 is a member formed, for example, by pressing sheet metal.

The main frame 101 has a flat support portion 101a, a first side surface 101b, a second side surface 101c, and a third side surface 101d. Specifically, the support portion 101a has an inner surface 101a-1, which is the first surface, and an outer surface 101a-2, which is the second surface.

The motor M, the gear train 140, and a pair of gears 161, 162 that make up the movement mechanism 160 are arranged on the inner surface 101a-1, which is the first surface. Furthermore, the cutter blade 131 (Figure 5) and other components are arranged on the outer surface 101a-2, which is the second surface. The first surface is an example of an inner surface support section in this invention, and the second surface is an example of an outer surface support section. Note that the main frame 101 is not necessarily limited to a roughly box shape. As in this embodiment, the motor M, gear train 140, etc., and the cutter blade 131, etc., are arranged separately on both sides of the support section 101a, allowing for efficient component placement.

(Gear train 140)
7 , the gear train 140 has a planetary gear unit 141, a bevel gear 151, and an intermediate gear 153. In the configuration of this embodiment, the planetary gear unit 141 connected to the motor M is provided, and the rotation of a tip gear 145 a having bevel-shaped teeth on an output shaft 145 of the planetary gear unit 141 is transmitted to the movement mechanism 160 via the gear train 140 including the bevel gear 151. This causes the movement mechanism 160 to rotate and move the cutter blade 131.

As shown in FIG. 10, the planetary gear unit 141 includes a sun gear Mb, a gear housing member 141-1, a side plate 141-2, a carrier plate 141-3, multiple planetary gears 143, a rotating member 144, and an output shaft 145.

The planetary gear unit 141 is attached to the motor M and functions as a reduction gear. Compared to reduction gears consisting of multiple gears, the planetary gear unit 141 can achieve a large reduction ratio with a smaller number of gears. In addition, since the input shaft and output shaft can be arranged coaxially, a compact configuration can be achieved.

The sun gear Mb is fixed to the output shaft Ma of the motor M. The gear housing member 141-1 and side plate 141-2 form part of the gear housing that houses the sun gear Mb and planet gears 143. The carrier plate 141-3 is also housed within the gear housing. An internal gear 141g, with which multiple planet gears 143 mesh, is formed on the inner circumferential surface of the gear housing member 141-1.

In the assembled state, the sun gear Mb is located at the center of the internal space of the gear housing member 141-1. In this embodiment, three planetary gears 143 are arranged radially outward from the sun gear Mb and inside the internal gear 141g. As an example, the three planetary gears 143 are arranged at equal intervals in the circumferential direction. When the sun gear Mb rotates around the output shaft Ma of the motor M, the three planetary gears 143 also rotate in unison. Note that in this example, there are three planetary gears 143, but four (or multiple) planetary gears 143 may also be provided.

The rotating member 144 has three pins 144a, each inserted into a central hole in the planetary gear 143 and supported by the gear housing member 141-1. The rotating member 144 also has an output shaft 145. A tip gear 145a is provided at the tip of the output shaft 145.

The planetary gear unit 141 is configured as described above, so that the output from the motor M is transmitted by the planetary gear unit 141. Specifically, when the sun gear Mb fixed to the output shaft Ma of the motor M rotates, the multiple planetary gears 143 rotate around the output shaft Ma so as to revolve within the gear housing member 141-1. Then, in response to the rotation of the multiple planetary gears 143, the output shaft 145 and the tip gear 145a fixed thereto rotate.

See Figures 11 and 12. The bevel gear 151 is a gear with bevel-shaped teeth that mesh with the tip gear 145a. The bevel gear 151 is positioned so that its rotation axis is perpendicular to the axis of the output shaft 145 of the planetary gear unit 141. This changes the output direction from the motor M by 90 degrees.

The intermediate gear 153 meshes with teeth 151g (Figure 13) formed on a portion (lower stage) of the bevel gear 151, and rotates in response to the rotation of the bevel gear 151. The intermediate gear 153 meshes with the first cutter gear 161 (described below), and the rotation of the intermediate gear 153 causes the first cutter gear 161 to rotate. Specifically, as shown in Figure 13, the intermediate gear 153 has a large diameter toothed portion 153a and a small diameter toothed portion 153b located below the large diameter toothed portion 153a. The number of teeth on the large diameter toothed portion 153a is greater than the number of teeth on the toothed portion 151g of the bevel gear 151. The toothed portion 151g meshes with the large diameter toothed portion 153a of the intermediate gear 153, and the small diameter toothed portion 153b meshes with the first cutter gear 161. Although the tooth portion 151g of the bevel gear 151 may be configured to directly mesh with the first cutter gear 161 or the second cutter gear 162, the configuration of this embodiment allows the rotational force to be transmitted to the first cutter gear 161 at the desired gear ratio via the intermediate gear 153.

(Movement mechanism 160)
In the printing mechanism 100 of this embodiment, printed paper can be cut by the cutter blade 131. Various configurations are possible for the mechanism that uses the output from the motor M to move the cutter blade 131, but in this embodiment, the first cutter gear 161 and the second cutter gear 162 are rotated approximately half a turn, and the cutter blade 131 is moved by using a pin that moves in an arc as a result. This will be described in detail below.

The movement mechanism 160 is a mechanism that moves the cutter blade 131, and has a first cutter gear 161 and a second cutter gear 162, as shown in Figures 7, 8, and 9, for example.

The first cutter gear 161 and the second cutter gear 162 are both positioned inside the main frame 101. The first cutter gear 161 is supported by shaft 155a, and the second cutter gear 162 is supported by shaft 155b. Specifically, the first cutter gear 161 is positioned so that its rotation axis extends perpendicular to the support portion 101a of the main frame 101. Similarly, the second cutter gear 162 is positioned so that its rotation axis extends perpendicular to the support portion 101a of the main frame 101. Note that the "rotation axis" here corresponds to the central axis of each of shafts 155a and 155b.

The first cutter gear 161 is located on the side of the output shaft 145 of the motor M that is farther from the motor M in the axial direction, and the second cutter gear 162 is located on the side closer to the motor M. The first cutter gear 161 has teeth that mesh with the intermediate gear 153, and rotates in response to the rotation of the intermediate gear 153. The second cutter gear 162 has teeth that are the same shape as the teeth of the first cutter gear 161, and meshes with the first cutter gear 161.

Figure 13 is a diagram showing the detailed structure of the moving mechanism 160 and gear train 140. Note that the configuration depicted in Figure 13 is a specific example of the present invention, and the number of gear teeth, the size relationship and arrangement of the gear diameters, etc., to the extent that can be read from the drawing, constitute the disclosure of this application.

As shown in Figure 13, the first cutter gear 161 is configured so that the rotation of the bevel gear 151 is transmitted via the intermediate gear 153. The first cutter gear 161 has a pin 161p formed inward from the teeth and at a position radially away from the rotation axis Ax (the central axis of shaft 155a) of the gear. Similarly, the second cutter gear 162 has a pin 162p formed inward from the teeth and at a position radially away from the rotation axis Ax (the central axis of shaft 155b) of the gear.

Pin 161p is a columnar or cylindrical structural part that extends along the thickness direction of the first cutter gear 161. Pin 162p has a similar structure.

As shown in FIG. 13, the first cutter gear 161 is configured to rotate approximately 180° from a state in which the pin 161p is located at position P1a to a state in which the pin 161p is located at position P1b. The second cutter gear 162 is configured to rotate approximately 180° in response to the rotation of the first cutter gear 161, from a state in which the pin 162p is located at position P2a to a state in which the pin 162p is located at position P2b. The rotation direction of the second cutter gear 162 at this time is opposite to the rotation direction of the first cutter gear 161. Note that although approximately 180° is illustrated in this example, the rotation range of the first cutter gear 161 and the second cutter gear 162 can be set as desired.

The rotation range of the first cutter gear 161 and the second cutter gear 162 is restricted, for example, by a switch Sw (Figure 8) that abuts against a portion of the second cutter gear 162 and the control unit 190 (Figure 2). Specifically, as shown in Figure 8, the second cutter gear 162 is formed with multiple steps 162t that abut against the lever Swl of the switch Sw to switch between ON and OFF operation.

The multiple steps 162t include one step 162t-1 formed on part of the cylindrical protrusion of the second cutter gear 162, and the other step 162t-2 formed at a position 180° opposite in the circumferential direction from step 162t-1. As an example, both steps 162t-1 and 162t-2 are flat surfaces extending in the thickness direction of the gear.

Regarding the control of motor M operation by control unit 190, specifically, the range of rotation of first cutter gear 161 and second cutter gear 162 is determined, for example, by the number of pulses provided by control unit 190 to motor M, which is a stepping motor. Motor M begins to rotate in response to a control signal from control unit 190, and the position where lever Swl is turned ON is set to the home position. From this home position, motor M rotates a predetermined number of steps sufficient to cut the paper. This causes first cutter gear 161 and second cutter gear 162 to rotate, and cutter blade 131 advances to cut the paper. Motor M then moves an overstep from the cutting position and stops with lever Swl turned ON. Then, control unit 190 rotates motor M in the reverse direction with lever Swl turned ON. This causes first cutter gear 161 and second cutter gear 162 to rotate in the reverse direction, and cutter blade 131 retracts. After that, when the first cutter gear 161 and second cutter gear 162 rotate to a predetermined position, the lever Swl turns OFF.

Using the method described above, the first cutter gear 161 and second cutter gear 162 are rotated through a rotation angle of approximately 180° in this embodiment, as an example. Note that while Figure 8 shows the lever Swl in contact with the side of the large diameter portion of the cylindrical protrusion, in reality, the various components are assembled so that the lever Swl is positioned at the small diameter portion of the cylindrical protrusion.

Figure 14 is a view of the main frame 101 from the side where the cutter blade 131 (Figure 4) is located. As shown in Figure 14, the main frame 101 is formed with an opening 101h-1 through which the pin 161p of the first cutter gear 161 passes, and an opening 101h-2 through which the pin 162p of the second cutter gear 162 passes. Both openings 101h-1 and 101h-2 are arc-shaped holes. As can be seen from Figure 14, openings 101h-1 and 101h-2 are provided with bilaterally symmetrical shapes. Pins 161p and 162p pass through openings 101h-1 and 101h-2 and protrude away from the outer surface 101a-2 of the main frame 101. Pins 161p and 162p are configured to move along openings 101h-1 and 101h-2.

Next, referring again to Figure 5, the cutter blade 131 is formed with openings 131h-1 and 131h-2 that extend laterally. Pin 161p passes through one opening 131h-1, and pin 162p passes through the other opening 131h-2.

With the above-described configuration, the first cutter gear 161 and the second cutter gear 162 rotate simultaneously, causing the pins 161p and 162p to move along an arc, applying a force to the cutter blade 131 in a direction that moves the cutter blade 131 in either the up or down direction in FIG. 5 (a force that moves the cutter blade 131 forward or backward). Specifically, if the direction in which the cutter blade 131 advances or retreats is defined as the Y-axis (the up or down direction in FIG. 1) and the extension direction of the openings 131h-1 and 131h-2 is defined as the X-axis (the left and right direction in FIG. 1), the arc movement of the pins 161p and 162p can be broken down into a force in the Y-axis direction and a force in the X-axis direction. The force in the Y-axis direction moves the cutter blade 131, and the force in the X-axis direction is released when the pins 161p and 162p move through the opening 131h.

The slider 132 in Figure 4 is a component that is positioned outside the cutter blade 131 and allows the cutter blade 131 to move smoothly. The blade spring 133 in Figure 3 is a component that presses the slider 132 and cutter blade 131 from the outside and has a spring pressure that allows the cutter blade 131 to move up and down smoothly.

(Bracket 170)
11 and 12 . In the configuration of this embodiment, a bracket 170 is provided within the main frame 101. In this example, the bracket 170 has a support portion 171 that supports the outer periphery of the output shaft 145 of the planetary gear unit 141. Specifically, the support portion 171 supports a portion of the output shaft 145. More specifically, the support portion 171 is formed so that its cross-sectional shape is approximately semicircular (including a portion of an arc) so as to support approximately half of the outer periphery of the output shaft 145. In this example, the bracket 170 is disposed on the inner surface 101a-1 of the main frame 101. Although not limited thereto, the bracket 170 is, as an example, a molded part made of resin. With the configuration in which the output shaft 145 is supported by the support portion 171 as described above, the position of the output shaft 145 is stabilized, shaft wobble is suppressed, and force can be transmitted effectively between the tip gear 145a and the bevel gear 151. The bracket 170 may be a metal member, and more specifically, may be an integral part made of metal.

(emergency gear)
15A and 15B are diagrams illustrating the emergency gear 157 and its surrounding structure. Fig. 15A shows the emergency gear alone, and Fig. 15B shows the main frame 101 on which the emergency gear 157 is disposed. In the paper cutting mechanism 130 of this embodiment, the emergency gear 157 is provided inside the main frame 101, as shown in Fig. 15A.

As shown in FIG. 15(a), the emergency gear 157 has an operating portion 157a and an umbrella-shaped bevel gear portion 157b. For example, the emergency gear 157 is a member in which the operating portion 157a, the bevel gear portion 157b, and other components are integrally formed. The operating portion 157a has a larger diameter than the bevel gear portion 157b. Specifically, for example, the operating portion 157a has a disk-like shape. For example, the bevel gear portion 157b may have a shape similar to the teeth of the bevel gear 151.

The emergency gear 157 is positioned so that the bevel gear portion 157b faces the bevel gear 151 (Figure 7) and meshes with the tip gear 145a (see also Figure 8). As shown in Figure 8, the emergency gear 157 is supported by a shaft 155 that supports the bevel gear 151. As an example, the emergency gear 157 is secured to the shaft 155 by an E-ring to prevent the emergency gear 157 from coming off the shaft 155. The tip gear 145a (Figure 7) is sandwiched between the bevel gear 151 and the emergency gear 157. As a result, the tip gear 145a and the bevel gear 151 can be stably meshed with each other. Although not shown in Figures 7 and 8, the upper end of the shaft 155 is supported by some of the components that make up the printing mechanism 100.

The emergency gear 157 is positioned so that the operating portion 157a partially protrudes from the opening 101s formed in the main frame 101. This configuration allows the user to touch the operating portion 157a from the outside and turn the emergency gear 157.

The opening 101s may be formed as a single closed opening (through hole) in the main frame 101, or as shown in Figure 15(b), it may be formed in a recessed shape and form a single closed opening when the main frame 101 is fixed to another member (not shown). In the case of a recessed opening 101s cut into the edge of the plate material of the main frame 101 (here, the edge of the third side surface 101d), as shown in Figure 15(b), this has the advantage that the shape can be easily formed by, for example, press working.

By rotating the emergency gear 157, the rotational force is transmitted to the bevel gear 151 via the tip gear 145a (see Figure 7, not shown in Figure 8), causing the bevel gear 151 to rotate. The rotation of the bevel gear 151 causes the first cutter gear 161 and the second cutter gear 162 to rotate. With this configuration, the user can manually move the emergency gear 157 to rotate the first cutter gear 161 and the second cutter gear 162 and move the cutter blade 131 in the advancing or retracting direction without relying on the power of the motor M.

(Effects of this embodiment)
As described above, the paper cutting mechanism 130 of this embodiment is provided with the planetary gear unit 141 and the bevel gear 151 that meshes with the tip gear 145a provided on the output shaft 145 of the planetary gear unit 141, and these transmit the rotational force of the motor M to the movement mechanism 160 that moves the cutter blade 131, so that a high torque driving force can be transmitted to the cutter blade. In addition, a configuration that uses the planetary gear unit 141 is also advantageous for miniaturization.

Furthermore, in the configuration of this embodiment, the outer periphery of the output shaft 145 of the planetary gear unit 141 can be stably supported by the support portion 171 of the bracket 170, and as a result, the tip gear 145a and the bevel gear 151 can be meshed with high precision. This allows the driving force of the motor M to be transmitted efficiently.

Furthermore, in the configuration of this embodiment, the tip gear 145a is sandwiched between the bevel gear 151 and the emergency gear 157. The emergency gear 157 is a component that allows the user to manually move the cutter blade 131, and essentially can be located anywhere as long as it performs that function. However, with the configuration of this embodiment in which the tip gear 145a is sandwiched between the bevel gear 151 and the emergency gear 157, the tip gear 145a and the bevel gear 151 mesh with each other with greater precision than in a configuration in which the emergency gear 157 is not provided.

Furthermore, in the configuration of this embodiment, the motor M, gear train 140, and movement mechanism 160 are arranged on the inner surface 101a-1, which is the first surface of the main frame 101, and the cutter blade 131 is arranged on the inner surface 101a-1, which is the second surface. This configuration, in which various components are arranged on both sides of a portion of the main frame 101, allows the various components to be arranged in a space-efficient manner, resulting in a compact device configuration.

(Cutting performance evaluation test)
FIG. 16 is a table showing the results of a cutting performance evaluation test. The results of an evaluation of the paper cutting performance of a paper cutting mechanism according to one embodiment of the present invention will be described with reference to FIG. 16 . The "Example" shows a paper cutting mechanism 130 equipped with a planetary gear unit 141, a bevel gear 151, and the like, while the "Comparative Example" shows a paper cutting mechanism without such mechanisms. Specifically, the paper cutting mechanism of the comparative example has a worm gear attached to the output shaft of the motor, and this worm gear meshes with one of a pair of cutter gears (second cutter gear 162, FIG. 9 ). Apart from this difference in the configuration for transmitting output from the motor, the other configurations are the same.

"Voltage" indicates the value of the voltage supplied to the motor. "Type 1" paper type is relatively thin paper, "Type 2" is thicker than Type 1, and "Type 3" is thicker than Type 2. When paper was cut using each paper cutting mechanism under these conditions, the example was able to cut all types of paper. In contrast, the comparative example was able to cut Type 1 well, but was unable to cut Types 2 and 3 well.

As such, it was confirmed that the paper cutting mechanism 130 according to one embodiment of the present invention can cut thicker paper better than the comparative example configuration equipped with a worm gear, even when the motor is operated at the same voltage.

The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and alterations are possible within the spirit of the invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of new embodiments resulting from the combination will also have the effects of the original embodiments.

100 Printing mechanism 101 Main frame 101a Support section 101a-1 Inner surface 101a-2 Outer surface 101b First side surface 101c Second side surface 101d Third side surface 101s Opening 105 Paper inlet section 106 Paper outlet section 110 Thermal head 120 Transport mechanism 121 Platen roller 122 Claw 123 Gear train 125 Guide plate 130 Paper cutting mechanism 131 Cutter blade 132 Slider 133 Blade spring 138 Fixed blade 140 Gear train 141 Planetary gear unit 141-1 Gear housing member 141-2 Side plate 141-3 Carrier plate 141g Internal gear 143 Planetary gear 144 Rotating member 144a Pin 145 Output shaft 145a Tip gear 151 Bevel gear 151g Toothed portion 153 Intermediate gear 153a Large diameter tooth portion 153b Small diameter tooth portion 155a Shaft 155b Shaft 157 Emergency gear 157a Operating portion 157b Bevel gear portion 160 Moving mechanism 161 First cutter gear 162 Second cutter gear 162t Step portion 170 Bracket 171 Support portion 190 Control portion 200 Roll holding member 201a Roll holding portion Ax Rotation shaft L Lever M Motor Ma Output shaft Mb Sun gear S1 Thermal printer Sh Paper Sw Switch Sw1 Lever

Claims (8)

A paper cutting mechanism that advances a cutter blade against paper to cut the paper,
A motor;
a gear train that transmits power from the motor;
a main frame supporting the motor and the gear train;
a movement mechanism that moves the cutter blade back and forth using the power transmitted by the gear train;
Equipped with
The gear train includes:
a planetary gear unit connected to the motor;
a bevel gear that meshes with a tip gear provided on an output shaft of the planetary gear unit;
and
The rotation of the tip gear is transmitted to the movement mechanism via the bevel gear, and the movement mechanism moves the cutter blade,
The moving mechanism includes:
a first cutter gear to which the rotation of the bevel gear is transmitted, the first cutter gear having a pin formed at a position radially spaced from a rotation axis of the gear;
a second cutter gear that meshes with the first cutter gear and has a pin formed at a position radially spaced from a rotation axis of the second cutter gear ;
and
The cutter blade has openings through which the pins of the first cutter gear and the second cutter gear are passed,
When the first cutter gear and the second cutter gear rotate simultaneously, each pin applies a force to the cutter blade in a direction to advance or retreat the cutter blade, thereby moving the cutter blade forward or backward.
Paper cutting mechanism. a bracket having a bearing portion formed thereon for supporting an outer periphery of the output shaft of the planetary gear unit;
The support portion has a cross-sectional shape that includes a part of a circular arc.
2. The paper cutting mechanism of claim 1 . The planetary gear unit further includes an emergency gear that is disposed to face the bevel gear and has a bevel gear portion that meshes with the tip gear provided on the output shaft of the planetary gear unit,
The tip gear is sandwiched between the bevel gear and the emergency gear.
3. The paper cutting mechanism according to claim 1 or 2. The emergency gear has a disk-shaped operating portion formed with a diameter larger than that of the bevel gear portion,
At least a part of the operating unit protrudes outward from the main frame that houses the emergency gear so that a user can touch the operating unit.
4. The paper cutting mechanism of claim 3 . the main frame has a first surface and a second surface;
the motor, the gear train, and the movement mechanism are disposed on the first surface;
The cutter blade is disposed on the second surface.
3. The paper cutting mechanism according to claim 1 or 2. The paper cutting mechanism according to claim 1 or 2;
a thermal head for printing on the paper;
a platen roller for pressing the paper against the thermal head and discharging the paper;
A printing mechanism comprising: a paper cutting mechanism that moves a cutter blade against the paper to cut the paper;
a thermal head that prints on paper;
a platen roller that sandwiches the paper between itself and the thermal head and feeds the paper;
a main frame having an inner support portion and an outer support portion for supporting the paper cutting mechanism;
a holder for holding a roll from which the paper is drawn;
Equipped with
the paper cutting mechanism includes a motor, a gear train that transmits power from the motor, and a movement mechanism that moves the cutter blade forward and backward using the power transmitted by the gear train;
the motor, the gear train, and the moving mechanism are disposed on the inner surface support portion,
The gear train includes:
a planetary gear unit connected to the motor;
a bevel gear that meshes with a tip gear provided on an output shaft of the planetary gear unit;
and
The rotation of the tip gear is transmitted to the movement mechanism via the bevel gear, and the movement mechanism moves the cutter blade,
The moving mechanism includes:
a first cutter gear to which the rotation of the bevel gear is transmitted, the first cutter gear having a pin formed at a position radially spaced from a rotation axis of the gear;
a second cutter gear that meshes with the first cutter gear and has a pin formed at a position radially spaced from a rotation axis of the second cutter gear;
and
The cutter blade has openings through which the pins of the first cutter gear and the second cutter gear are passed,
When the first cutter gear and the second cutter gear rotate simultaneously, each pin applies a force to the cutter blade in a direction to advance or retreat the cutter blade, thereby moving the cutter blade forward or backward.
Thermal printer. The thermal printer according to claim 7 , wherein the cutter blade is provided on the outer surface support portion.