JP3118707U - Roll paper storage mechanism - Google Patents

Abstract

An object of the present invention is to stabilize the position of roll paper fed out intermittently and to suppress the occurrence of slack in the roll paper roll.
A roll paper storage mechanism includes a fixed roller provided below the roll paper, and a first rotating roller provided upstream of the fixed roller and at a position higher than the fixed roller. A second rotating roller 13 provided upstream of the first rotating roller 12 and higher than the first rotating roller 12; and a second rotating roller upstream of the second rotating roller 13 and the second rotating roller. A guide roller 15 provided at a position higher than 13 is provided. Since the center of gravity of the roll paper 9 is moved toward the fixed roller 11, the position can be stabilized even if the roll paper 9 is pulled intermittently. Further, since the fixed roller 11 that is always in contact with the roll paper 9 is used as a friction member, the roll paper 9 is not rotated too much by inertia force.
[Selection] Figure 5

Description

  The present invention relates to a roll paper storage mechanism, and in particular, in order to facilitate roll paper replacement of a thermal printer, the roll paper is stabilized from the roll paper storage unit to the printing unit in a so-called throw-in type storage structure. The present invention relates to a paper feed mechanism in a roll paper storage unit for feeding in a normal manner.

  In recent years, thermal printers have been widely used as printing apparatuses for receipts received when shopping at convenience stores and supermarkets. A thermal printer is a type of printer that prints by heating thermal paper with a thermal head. Usually, thermal paper is provided as roll paper, and there are various roll paper widths and diameters depending on the application.

In the case of a thermal printer, the roll paper must be replaced when it is almost time to run out of paper, and if it is used frequently, it may be replaced several times a day. Therefore, in a thermal printer of a type that uses an axial core inserted into the center hole of the roll paper (see, for example, Patent Document 1), it is difficult to set the roll paper and the setting of the roll paper is troublesome. The so-called throw-in type thermal printer, in which the setting is completed simply by inserting the printer into the roll paper storage unit, is popular.
JP 2002-87649 A

  By the way, in the conventional roll paper throwing type thermal printer, in the printing operation, the position of the roll paper in the roll paper storage unit becomes unstable, and erroneous detection is likely to occur in the roll paper out-of-paper detection (near-end detection). Had a problem. This type of problem does not occur in a thermal printer in which the axis passes through the axis of the roll paper, so that the roll paper position is stable. In addition, when the roll paper immediately after setting the roll paper still remains, if the roll paper is pulled intermittently by the paper feeding / printing unit, the entire roll paper rotates more than necessary due to its inertial force, There has been a problem in that the roll of the roll paper is loosened, making it difficult to run the paper, and in the worst case, the paper is jammed. These problems become more prominent as the printing speed becomes faster, and this is one of the factors that hinder the improvement of the printing speed of the thermal printer.

  In order to solve the above problem, as shown in FIG. 8, a guide roller 31 is provided above the roll paper 9 loading position and behind the center of the roll paper 9, and the roll paper 9 is pulled upward. A roll paper storage mechanism 30 having a mechanism is also known. When the roll paper 9 is pulled upward, the weight of the roll paper 9 plays a role against the pulling of the roll paper 9, so that the roll paper 9 swings back and forth and the position of the roll paper 9 becomes unstable. It is possible to prevent a situation in which the roll paper 9 rotates more than necessary due to inertia and the winding portion of the roll paper 9 becomes slack.

  However, in the conventional roll paper storage mechanism 30 shown in FIG. 8, not only a new member such as a guide roller 31 needs to be added, but also the presence of the new guide roller 31 obstructs the setting by throwing the roll paper. In practice, therefore, a troublesome operation of setting the roll paper 9 after moving the guide roller 31 is required. That is, there is a problem that not only the cost is increased by newly installing the guide system, but also the workability at the time of replacing the roll paper is greatly reduced due to the structure in which the roll paper 9 is difficult to set.

  Accordingly, an object of the present invention is to provide a roll paper storage mechanism capable of stabilizing the position of the roll paper regardless of intermittent roll-out of the roll paper and reducing the occurrence of slack in the roll paper winding portion. There is.

  The above object of the present invention includes a contact member that is provided below a roll paper loading position and is always in contact with the roll paper, and a plurality of rotating rollers provided on the upstream side of the contact member. The roll paper storage mechanism is characterized in that the rotation roller is arranged so that the contact point between the roll paper and the rotation roller sequentially shifts to the rotation roller close to the contact member as the diameter of the roll paper decreases. Achieved by: Here, the “upstream side” is based on the feeding direction of the roll paper, and the feeding direction of the roll paper is defined as the upstream side with respect to a certain reference position, and the opposite side to the feeding direction is defined as the downstream side.

  In the present invention, the plurality of rollers are provided at least at a position upstream of the contact member and higher than the contact member, and the diameter of the roll paper is equal to or smaller than a first diameter smaller than the maximum diameter. A first rotating roller in contact with the roll paper, and a position upstream of the first rotating roller and higher than the first rotating roller, and the diameter of the roll paper is equal to or greater than the first diameter. It is preferable that a second rotating roller in contact with the roll paper is provided. Here, “always contact” means that the contact member is always in contact with the roll paper even when the first rotation roller is not in contact with the roll paper and when the second rotation roller is not in contact with the roll paper. Needless to say, this does not exclude the case where the roll paper temporarily does not come into contact with the contact member due to external force.

  In the present invention, when the roll paper is provided at a position upstream of the second rotating roller and higher than the second rotating roller, and the diameter of the roll paper is equal to or smaller than a second diameter smaller than the maximum diameter. It is preferable to further include a guide roller for guiding the feeding of the roll paper. According to this, even if roll paper is consumed and becomes a small diameter, roll paper can be smoothly fed out. Also, even if the roll paper is pulled by the paper feed / printing section, even if the roll paper moves as a whole, the guide roller functions as a stopper that suppresses the movement of the roll paper, so that the roll paper can be immediately returned to its original stable position. Can do.

  In the present invention, the contact member is preferably a fixed roller that contacts in a fixed state irrespective of the rotation of the roll paper. When a fixed roller is used as the contact member, the same roller as the first rotating roller or the like can be used, so that parts can be shared.

  In the present invention, at least the second rotary roller is provided at regular intervals in the width direction of the normal roll surface having a predetermined friction coefficient and the second rotary roller, and is more frictional than the first roll surface. It is more preferable to provide a high friction roll surface with a large coefficient. When the high friction roll surface is formed on at least the second roller, it is possible to further suppress the looseness of the roll paper. Such a high friction roll surface can be formed not only on the second rotating roller but also on the first rotating roller.

  In the present invention, it is preferable that an interval between the contact member and the first rotating roller is narrower than a minimum near-end detection diameter of the roll paper, and an interval between the first rotating roller and the second rotating roller is the More preferably, it is narrower than the minimum diameter of the roll paper. Here, the “near-end detection minimum radius” refers to a minimum value in a range that can be detected by adjusting the position of the near-end detection sensor among the near-end detection radii of the roll paper. According to this, the roll paper does not fall into the interval between the contact member and the first rotation roller before the near end is detected, and even when the radius of the roll paper is minimized, the first rotation roller and the second rotation roller There is no drop in the interval between the rotating rollers.

  The first diameter of the roll paper is preferably 40 to 80% of the maximum diameter of the roll paper. If the first diameter is set within this range, the contact point between the roll paper and the rotating roller can be smoothly switched according to the change in the weight of the roll paper.

  According to the present invention, there is provided a roll paper storage mechanism in which the position of the roll paper is sufficiently stable regardless of intermittent roll paper feeding, and the occurrence of loosening of the roll paper winding portion is greatly reduced. Can do.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 are schematic perspective views showing a configuration of a thermal printer 1 having a roll paper storage mechanism according to the first embodiment of the present invention. FIG. 1 shows a state where roll paper is present, and FIG. 2 shows a roll. It shows the state where there is no paper.

  As shown in FIGS. 1 and 2, the thermal printer 1 intermittently connects a support base 2, a roll paper storage unit 3 installed on the support base 2, and a roll paper 9 stored in the roll paper storage unit 3. Near end detection for notifying that the remaining amount of roll paper 9 has become less than a predetermined amount (predetermined diameter), paper feed / printing section 4 for printing while pulling in, paper cutter section 5 for cutting the roll paper after printing The sensor 6 is provided. Here, “upstream side” refers to a side closer to the feeding direction of the roll paper 9 than a certain reference position, and a side opposite to the feeding direction of the roll paper 9 is referred to as “downstream side”.

  The support base 2 is formed by bending a metal plate, and includes left and right leg portions and an attachment surface for the paper feed printing portion 4. A control circuit board is accommodated in the support base 2, and each part of the thermal printer 1 is controlled by this control circuit. The roll paper storage unit 3 installed on the upper surface of the support base 2 includes a roll paper storage mechanism for smoothly feeding the roll paper 9 to the paper feeding / printing unit 4. The paper feeding / printing unit 4 is a mechanism for performing printing while pulling the roll paper 9 intermittently, and includes a thermal head or the like. Here, the gap between the roll paper storage unit 3 and the paper feeding / printing unit 4 needs to be set at an interval that is not too wide within a range in which paper can be easily inserted. This is because if the roll paper 9 is too wide, the roll paper 9 is easily loosened. The paper cutter unit 5 is interlocked with the paper feeding / printing unit 4 and cuts the roll paper 9 that has been printed. The near-end detection sensor 6 is disposed on the side surface of the roll paper storage unit 3 and is disposed obliquely in accordance with the direction in which the center hole moves as the roll paper 9 decreases. The near-end detection sensor 6 is screwed and fixed to the mounting surface, but the fixing hole formed on the mounting surface is an oblong hole, so that the near-end detection diameter is within a predetermined range at the discretion of the user. The structure can be adjusted with.

  The roll paper 9 used in this embodiment is thermal paper having a surface coated with a thermal material. The roll paper 9 has several specified sizes such as a width / maximum diameter of 2 inches / 90 mm, 3 inches / 90 mm, and 4 inches / 90 mm, respectively, and the roll paper storage unit 3 has dimensions corresponding to any of these sizes. It has become. Such roll paper 9 is set in the roll paper storage unit 3 by a throw-in method. That is, when setting the roll paper 9, the roll paper 9 is placed in the roll paper storage unit 3, the end of the roll paper 9 is inserted into the paper insertion opening of the paper feeding / printing unit 4, and the end is then fed to the paper. The paper is discharged from the paper discharge port 5a on the cutter unit 5 side. As described above, according to the thermal printer of the present embodiment, an operation such as inserting the shaft center into the roll paper 9 is not required, and the roll paper 9 is set by simply placing it in the roll paper storage unit 3. Therefore, setting of roll paper is very easy.

  3 is a schematic perspective view showing a configuration of the roll paper storage mechanism 10 by the roll paper storage unit 3, and FIG. 4 is a schematic side sectional view showing a state before the roll paper 9 is stored. ing.

  As shown in FIG. 3 and FIG. 4, the roll paper storage mechanism 10 is provided at a position higher than the fixed roller 11 and a fixed roller 11 provided below the roll paper loading position. From the first rotating roller 12, the second rotating roller 13 provided upstream of the first rotating roller 12 and higher than the first rotating roller 12, and the second rotating roller 13. In addition, a guide roller 15 provided on the upstream side and at a position higher than the second rotating roller 13 and a guide case 16 in which these rollers are installed are provided.

The guide case 16 constitutes the bottom surface and the side surface of the roll paper storage unit 3, and the bottom surface 16 a of the guide case is gently curved in accordance with the arc of the unused roll paper 9. In the roll paper storage mechanism 10 of the present embodiment, the guide case 16 is composed of two members that can be separated into left and right so as to be compatible with various roll papers having different paper widths. When the left and right sides of the guide case 16 are separate members, the width W ₀ of the guide case 16 can be changed depending on the mounting position thereof, so that the rollers 11, 12, 13, and 15 that match the width of the roll paper 9 are guided. If it is installed in the case 16, it becomes possible to handle the roll paper of various widths described above.

  The fixed roller 11 is a roller that is fixed so as not to rotate with the rotation of the roll paper 9. Since the fixed roller 11 is provided at a position lower than the other rollers 12 to 15, the fixed roller 11 is always in contact with the roll paper 9 regardless of the diameter of the roll paper 9 consumed. Since the fixed roller 11 generates a frictional force with the roll paper 9, even if the roll paper 9 is intermittently pulled by the paper feeding / printing unit 4, the entire roll paper 9 is rotated by its inertial force. It is not too much, and the winding part of the roll paper 9 can be prevented from loosening.

The first rotating roller 12 is a rotating roller that can freely rotate back and forth. The first rotating roller 12 is provided so as to be in contact with the roll paper 9 when the radius of the roll paper 9 is equal to or less than the _first radius R ₁ smaller than the maximum radius R _max . Therefore, when the radius of the roll paper 9 is larger than the first radius R ₁ , the roll paper 9 does not come into contact with the first rotating roller 12. The first radius R ₁ of the roll paper 9 is preferably 40 to 80% of the maximum radius R _max of the roll paper 9. Therefore, for example, when the maximum radius R _max of the roll paper is 45 mm (90 mmφ), the first radius R ₁ is set to 25 mm (50 mmφ). Further, when the radius of the roll paper 9 at which the above-mentioned near-end detection sensor 6 starts to react is the third radius (near-end detection radius) R ₃ , the distance between the fixed roller 11 and the first rotating roller 12 is the roll paper. It is set smaller than the near-end detecting the diameter 2R ₃ of 9. That is, the interval between the fixed roller 11 and the first rotating roller 12 is set such that the roll paper 9 is consumed, and even if the radius of the roll paper 9 becomes the near-end detection minimum radius, it does not fall between them. Has been. Here, the “near-end detection minimum radius” refers to the minimum value of the radius that can be detected by adjusting the position of the near-end detection sensor among the near-end detection radii of the roll paper.

Similar to the first rotating roller 12, the second rotating roller 13 is a rotating roller that can freely rotate back and forth. The second rotating roller 13 is provided so as to be in contact with the roll paper 9 when the radius of the roll paper 9 is equal to or larger than the _first radius R1. For this reason, when the radius of the roll paper becomes the first radius R ₁ , the roll paper 9 is temporarily in contact with all of the fixed roller 11, the first rotating roller 12 and the second rotating roller 13. . The interval between the first rotating roller 12 and the second rotating roller 13 is set such that even when the radius of the roll paper 9 reaches its minimum diameter R _min , it does not fall between them.

The guide roller 15 contacts the roll paper 9 when the radius of the roll paper 9 is equal to or smaller than the second radius R ₂ smaller than the maximum radius R _max and guides the feeding of the roll paper 9. The second radius R ₂ is preferably set to 55 to 95% of the maximum radius R _max of the roll paper 9. As long as these conditions are satisfied, the second radius R ₂ may be different from or the same as the first radius R ₁ . When the radius of the roll paper 9 is larger than the second radius R ₂ , the roll paper 9 is basically pulled even if the roll paper 9 is intermittently pulled by the paper feeding / printing unit 4 to temporarily contact the guide roller 15. It is in a positional relationship not in contact with the winding part. When the roll paper 9 is consumed and the radius of the roll paper 9 reaches the second radius R ₂ , the roll paper 9 starts to contact the guide roller 15 and changes the paper traveling direction until the roll paper 9 is used up. Then, it is guided so as to be fed into the paper insertion opening of the paper feeding / printing unit 4.

  As the material of these four rollers 11 to 15, it is preferable to use a resin having a high mechanical strength, and for example, a polyacetal resin (Derlin) or the like can be used. In particular, in the present embodiment, rubber materials (O-rings) 17 are provided at equal intervals on the surface of the second rotating roller 13, thereby partially forming a high friction roll surface having a large friction coefficient. . The roll paper 9 is preferably rotated in the same manner as the second rotating roller 13, but when the remaining amount of the roll paper 9 is still sufficient and the roll paper 9 has a certain weight, the roll paper 9 May rotate due to its inertial force. However, when the second rotating roller 13 partially has a high friction roll surface, excessive rotation of the roll paper 9 can be suppressed.

  When a new roll paper 9 is set in the roll paper storage mechanism 10 having the above-described configuration, first, the roll paper 9 is first placed in the guide case 16 with the leading end thereof facing downward, The leading end is fed into the paper insertion port 4a of the paper feeding / printing unit 4 and further fed out from the paper discharge port 5a of the paper cutter unit 5. Thus, according to this embodiment, the roll paper 9 can be set easily.

  Next, the operation of the roll paper storage mechanism 10 will be described with reference to FIGS.

  First, as shown in FIG. 5, at the initial stage when a new roll paper 9 is set, the roll paper 9 is in contact with both the fixed roller 11 and the second rotary roller 13, but the first rotary roller 12. Not touching. Here, the position of the fixed roller 11 is lower than that of the second rotating roller 13, and a sufficient level difference is provided between the fixed roller 11 and the second rotating roller 13. 11, and the center of gravity of the roll paper 9 can be shifted to the side opposite to the direction in which the roll paper 9 is pulled, that is, to the fixed roller 11 side.

  The roll paper 9 set in the storage unit in this way rotates when its end is intermittently pulled by the paper feeding / printing unit 4. Paying attention to one point on the roll paper 9, after one point on the roll paper 9 passes through the second rotating roller 13, the first rotating roller 12, and the fixed roller 11 and is peeled off from the winding portion of the roll paper 9. The paper feeding / printing unit 4 is pulled into the paper insertion opening 4a. Then, it is printed by the paper feeding / printing unit 4 and cut by the paper cutter unit 5. Note that, as long as the radius of the roll paper 9 is relatively large, the portion of the roll paper 9 peeled off from the winding portion does not contact the guide roller 15.

  In this way, the roll paper 9 is in contact with both the fixed roller 11 and the second rotating roller 13, and the center of gravity of the roll paper 9 is moved toward the fixed roller 11. Even when the whole 9 is pulled in the pull-in direction, the roll paper 9 does not move in the pull-in direction as in the prior art. Even if it moves, the roll paper 9 hits the guide roller 15 and immediately returns to the original stable position. Thus, as long as the radius of the roll paper 9 is large, the guide roller 15 serves as a stopper that suppresses the movement of the roll paper 9, but the roll paper 9 is fed from the winding portion to the paper insertion port 4 a of the paper feeding / printing unit 4. Therefore, the guide roller 15 does not exhibit its original guide function.

  When the roll paper 9 has a sufficient remaining amount, if the roll paper 9 is pulled intermittently, the roll paper 9 does not stop rotating due to the inertial force of the roll paper 9, and the roll paper 9 is fed to the paper feed / printing unit 4. There is a possibility that the roll will be rotated more than the amount of pull-in caused by the slack and slack may occur in the winding portion of the roll paper 9. However, in the present embodiment, since the fixed roller 11 brakes the rotation of the roll paper 9 by the frictional force, the rotation of the roll paper 9 due to the inertial force can be prevented.

Next, as shown in FIG. 6, when the roll paper 9 is consumed and its radius reaches the first radius R ₁ (R ₁ <R _max ), the roll paper 9 is temporarily fixed to the fixed roller 11, the first roll 11. The rotating roller 12 and the second rotating roller 13 are in contact with three points, and thereafter, the contact point between the roll paper 9 and the rotating roller shifts from the second rotating roller 13 to the first rotating roller 12. Also here, the position of the fixed roller 11 is lower than that of the first rotating roller 12, and a sufficient level difference is provided between the fixed roller 11 and the first rotating roller 12. 11, and the center of gravity of the roll paper 9 can be shifted to the fixed roller 11 side.

As described above, the roll paper 9 is in contact with both the fixed roller 11 and the first rotating roller 12, and the center of gravity of the roll paper 9 is moved toward the fixed roller 11. Even when the whole 9 is pulled in the pull-in direction, the roll paper 9 does not move in the pull-in direction as in the prior art. Even if it moves, the roll paper 9 hits the second rotating roller 13 (and also the guide roller 15) and immediately returns to the original stable position. Thus, the radius of the roll paper 9 is first radius R ₁ below, serves as a stopper for the second rotation roller 13 to inhibit movement of the roll paper 9. On the other hand, when the radius of the roll paper 9 is equal to or less than the second radius R ₂ (here, R ₂ ≧ R ₁ ), the roll paper 9 comes into contact with the guide roller 15, so that the roll paper 9 advances by the guide roller 15. The direction is changed, and the sheet is guided to the sheet insertion opening 4 a of the sheet feeding / printing unit 4.

Furthermore, as shown in FIG. 7, when the radius reaches the third radius (near-end detection radius) R ₃ roll paper 9 is further consumed, the near-end detecting sensor 6 shown in FIGS. 1 and 2 is that state Is detected and notified to the user. Note that the roll paper 9 at this time is also in contact with both the fixed roller 11 and the first rotating roller 12, and the center of gravity of the roll paper 9 is brought closer to the fixed roller 11, so that the roll paper 9 is intermittently drawn. Even when the entire paper 9 is pulled in the drawing direction, the roll paper 9 does not move in the drawing direction as in the prior art. Even if it moves, the roll paper 9 hits the second rotating roller 13 (and also the guide roller 15) and immediately returns to the original stable position. Therefore, erroneous detection in the near-end detection of the roll paper 9 can be greatly reduced. Further, since the roll paper 9 is in contact with the guide roller 15, the roll paper 9 is changed in the traveling direction by the guide roller 15 and is guided to the paper insertion opening 4 a of the paper feeding / printing unit 4.

As described above, according to the present embodiment, the fixed roller 11 is provided at a position lower than the first rotating roller 12, and the center of gravity of the roll paper 9 is brought closer to the fixed roller 11 side. Even when the entire roll paper 9 is pulled in the pull-in direction due to intermittent pull-in, the situation in which the roll paper 9 moves in the pull-in direction as in the past can be greatly reduced. Further, even if the roll paper 9 is moved if, first mainly in the case when the radius of the roll paper 9 is first radius R ₁ or more guide rollers 15, also of the first radius R ₁ or less 2 Since each of the rotating rollers 13 functions as a stopper, the roll paper 9 can be immediately returned to the original stable position. Therefore, erroneous detection in the near-end detection of the roll paper 9 can be greatly reduced, and paper jams due to loosening of the winding portion of the roll paper 9 can be prevented.

  In addition, according to the present embodiment, the fixed roller 11 that is always in contact with the roll paper 9 is used as a friction member, and the fixed roller 11 serves as a brake. Therefore, when the roll paper 9 is pulled intermittently, It is possible to suppress a situation in which the inertial force rotates too much. Therefore, it is possible to prevent the winding portion of the roll paper 9 from being loosened or jammed.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention, and these are also included in the scope of the present invention. Needless to say.

  For example, in the above-described embodiment, the case where four rollers including a fixed roller, a first rotating roller, a second rotating roller, and a guide roller are used has been described. However, in the present invention, the number of rollers is particularly limited. As long as the roll paper is consumed, the number of rollers may be five or more as long as the contact position between the roll paper and the rotating roller is changed in order. When a new rotating roller is added, it is possible to reliably feed a larger roll paper.

  In the above embodiment, the fixed roller 11 is used as a member that the roll paper 9 always contacts regardless of its diameter. However, the present invention is not limited to the fixed roller 11, and any contact that is fixedly contacted. Any member may be used. Moreover, if it is a shape similar to a fixed roller, it is not necessary to be a member different from the guide case 16, and a part of the guide case 16 may be used as a contact member.

  In the above embodiment, the case where the O-ring 17 is fitted on the surface of the second rotating roller 13 has been described. However, the roll surface is roughened instead of the O-ring 17 or the entire roll surface is made of rubber. A high friction roll surface may be formed by using a material or the like. In the present invention, the O-ring 17 is not necessarily required, but it can be said that it is preferable to provide the O-ring from the viewpoint of preventing the winding portion of the roll paper 9 from loosening. The O-ring may be provided not only on the second rotating roller 13 but also on the first rotating roller 12.

1 is a schematic perspective view showing a configuration of a thermal printer 1 including a roll paper storage mechanism according to a first embodiment of the present invention, and shows a state where roll paper is present. 1 is a schematic perspective view showing a configuration of a thermal printer 1 including a roll paper storage mechanism according to a first embodiment of the present invention, and shows a state without roll paper. FIG. 3 is a schematic perspective view showing a configuration of a roll paper storage mechanism 10 by the roll paper storage unit 3 and shows a state before the roll paper 9 is stored. FIG. 5 is a schematic side sectional view showing the configuration of the roll paper storage mechanism 10 by the roll paper storage unit 3, and shows a state before the roll paper 9 is stored. 4 is a schematic side sectional view for explaining the operation of the roll paper storage mechanism 10. FIG. 4 is a schematic side sectional view for explaining the operation of the roll paper storage mechanism 10. FIG. 4 is a schematic side sectional view for explaining the operation of the roll paper storage mechanism 10. FIG. FIG. 6 is a schematic side sectional view showing a configuration of a conventional roll paper storage mechanism 30.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal printer 2 Support stand 3 Roll paper storage part 4 Paper feed / printing part 4a Paper insertion port 5 Paper cutter part 5a Paper discharge port 6 Near end detection sensor 9 Roll paper 10 Roll paper storage mechanism 11 Fixed roller 12 First rotation roller 13 Second rotating roller 15 Guide roller 16 Guide case 16a Bottom surface of guide case 17 O-ring 30 Roll paper storage mechanism 31 Guide roller

Claims (7)

  A contact member that is provided below the roll paper loading position and that is always in contact with the roll paper; and a plurality of rotating rollers provided on the upstream side of the contact member, the plurality of rotating rollers including the roll paper The roll paper storage mechanism is arranged such that the contact point between the roll paper and the rotating roller sequentially shifts to the rotating roller close to the contact member as the diameter of the roll paper decreases.   The plurality of rotating rollers are provided at least at a position upstream of the contact member and higher than the contact member, and the roll paper has a diameter equal to or smaller than a first diameter smaller than the maximum diameter. A first rotating roller in contact with the paper, and provided at a position upstream of the first rotating roller and higher than the first rotating roller, and the diameter of the roll paper is equal to or larger than the first diameter The roll paper storage mechanism according to claim 1, further comprising a second rotating roller in contact with the roll paper.   When the roll paper is provided at a position upstream of the second rotation roller and higher than the second rotation roller, and the diameter of the roll paper is equal to or smaller than a second diameter smaller than the maximum diameter, the roll paper is fed out. The roll paper storage mechanism according to claim 2, further comprising a guide roller for guiding the paper.   The second rotating roller is provided at regular intervals in the width direction of the normal roll surface having a predetermined friction coefficient and the second rotating roller, and has a high friction coefficient larger than that of the first roll surface. The roll paper storage mechanism according to claim 2, further comprising a roll surface.   5. The roll paper storage mechanism according to claim 1, wherein the contact member is a fixed roller that contacts in a fixed state irrespective of the rotation of the roll paper. 6.   6. The roll paper storage mechanism according to claim 1, wherein a distance between the contact member and the first rotating roller is narrower than a minimum diameter of a near end detection of the roll paper. The roll paper storage mechanism according to any one of claims 1 to 6, wherein the first diameter of the roll paper is 40 to 80% of a maximum diameter of the roll paper.

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