Roll paper printer

Abstract

This invention provides a roll paper printer. The roll paper printer includes: a housing capable of housing a roll of paper wound with one side of the paper facing outwards; a conveyor roller for drawing paper from the roll and conveying it in a conveying direction; a first paper guide capable of abutting against the other side of the paper upstream of the conveyor roller in the conveying direction; a second paper guide opposite to the first paper guide and capable of abutting against one side of the paper; a third paper guide that can be disassembled and bent by abutting against one side of the paper upstream of the second paper guide in the conveying direction; a sensor capable of detecting the third paper guide; and a control unit that, when the third paper guide is detected by the sensor, slows down the conveying speed of the paper conveyed by the conveyor roller compared to when the third paper guide is not detected.

Description

Technical Field

[0001] This disclosure relates to a roll paper printer. Background Technology

[0002] As shown in Patent Document 1, an apparatus has been known that includes a unit for correcting the curl of paper drawn from a roll of paper and for printing on the paper.

[0003] In the aforementioned apparatus, including when correcting the curling of paper, it is impossible to achieve an appropriate conveying speed corresponding to the conveying load.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2020-19609 Summary of the Invention

[0005] A roll paper printer includes: a housing for receiving a roll of paper wound with one side of the paper facing outwards; a conveyor roller for drawing the paper from the roll and conveying it in a conveying direction; a first paper guide that abuts against the other side of the paper upstream of the conveyor roller in the conveying direction; a second paper guide opposite to the first paper guide and abutting against the one side of the paper; a third paper guide that can be detached and abuts against the one side of the paper upstream of the second paper guide in the conveying direction to bend it; a sensor for detecting the third paper guide; and a control unit that, when the third paper guide is detected by the sensor, slows down the conveying speed of the paper conveyed by the conveyor roller compared to when the third paper guide is not detected. Attached Figure Description

[0006] Figure 1 This is a block diagram of a roll paper printer.

[0007] Figure 2 This is a schematic cross-sectional view of a roll paper printer with the third paper guide removed.

[0008] Figure 3 This is a schematic cross-sectional view of a roll paper printer with a third paper guide installed. Detailed Implementation

[0009] 1. First Implementation Method

[0010] 1-1. Structure of a roll paper printer

[0011] The following is for reference Figures 1 to 3The roll paper printer 1 described in the embodiment will be explained. Furthermore, a three-dimensional coordinate system will be used to explain the directions in the figures. For ease of explanation, the positive direction of the Z-axis will be referred to as "up" or simply "up," and the negative direction as "down" or simply "down." The positive direction of the X-axis will be referred to as "right" or simply "right," and the negative direction as "left" or simply "left." The positive direction of the Y-axis will be referred to as "front" or simply "front," and the negative direction as "back" or simply "back."

[0012] The roll-paper printer 1 described in this embodiment is used, for example, in a POS (Point of Sale) system. A POS system is a system used in retail businesses such as shopping malls, department stores, convenience stores, and mobile sales outlets, or in food service businesses such as restaurants, cafes, and izakayas. The roll-paper printer 1 used in a POS system prints receipts, coupons, tickets, etc., based on the goods or services offered.

[0013] like Figure 1 As shown, the roll paper printer 1 is configured to include a control unit 2, a storage unit 3, a head 4, a conveyor roller 5, and a switch 6 as a sensor.

[0014] Additionally, the roll paper printer 1, when equipped with a battery (not shown), can also be carried and used by store staff.

[0015] The control unit 2 is configured to include a CPU (Central Processing Unit) for unified control of all parts of the roll paper printer 1, a UART (Universal Asynchronous Receiver Transmitter) for input / output management, and an FPGA (Field Programmable Gate Array) or PLD (Programmable Logic Device) as logic circuitry. The CPU is also referred to as a processor. The storage unit 3 is configured to include flash ROM (Read Only Memory) as rewritable non-volatile memory, HDD (Hard Disk Drive), and RAM (Random Access Memory) as volatile memory.

[0016] The CPU of the control unit 2 reads the firmware and other programs stored in the non-volatile memory of the storage unit 3, and uses the RAM of the storage unit 3 as the working area to execute the program.

[0017] Furthermore, the storage unit 3 stores setting information used by the control unit 2 when performing control. This setting information includes information related to the conveying speed of the conveyor roller 5 and the energizing time of the head 4. Moreover, as described later, the control unit 2 can change the conveying speed of the conveyor roller 5 based on the detection result of the switch 6.

[0018] Reference Figure 2 The case where the roll paper printer 1 does not have a third paper guide 18 will be explained in detail.

[0019] like Figure 2 As shown, the roll paper printer 1 is configured to include, in addition to the head 4, the conveyor roller 5, and the switch 6, a housing 7, a cover 8, a storage section 9, a first paper guide 10, and a second paper guide 14.

[0020] A hinge (not shown) is provided at the top and front of the housing 7. The cover 8 is mounted on the housing 7 in a manner that allows it to rotate around the hinge.

[0021] The housing 7 includes a head 4, a switch 6, a storage section 9, and a second paper guide 14. The switch 6 is fixed to the housing 7 via the second paper guide 14. On the other hand, the cover 8 includes a conveyor roller 5 and a first paper guide 10.

[0022] Furthermore, the roll paper printer 1 can have either the head 4 or the conveyor roller 5 mounted on the housing 7, and either the head 4 or the conveyor roller 5 mounted on the cover 8.

[0023] Paper P is, for example, a strip of thermal paper. A thermal material is coated on one surface Pa of paper P, and an image can be printed using a head 4, which serves as a line-type thermal print head. The other side Pb of paper P is the side that abuts against the conveyor roller 5.

[0024] The control unit 2 can rotate the conveyor roller 5 based on the setting information of the storage unit 3, convey the paper P in the conveying direction indicated by the arrow, and energize the head 4 to print the image.

[0025] The printed paper P is cut by a shear (not shown) located downstream of the head 4 and the conveying roller 5 in the conveying direction, and is handed to the customer by the staff as a receipt, etc.

[0026] The roll of paper R is wound onto the core with the surface Pa of paper P on the outside and the back Pb on the inside. The closer paper P is to the core of the roll of paper R, that is, the closer it is to the smaller outer diameter of the roll of paper R, the stronger the curl. In addition, the thicker paper P is, the stronger the curl.

[0027] The width of paper P is 45mm to 80mm. It can also be configured such that the width of paper P is limited by a partition. The thickness of paper P is 0.040mm to 0.065mm. The diameter of the roll paper R is 50mm to 80mm. The diameter of the core is 12mm to 18mm. These values ​​are examples; other values ​​are also possible.

[0028] The roll of paper R can be stored in the storage section 9 located at the bottom of the housing 7. The cover 8 can be opened and closed on the housing 7. When the cover 8 is opened forward, the operator can operate in the storage section 9.

[0029] The operator opens the cover 8 and stores the roll paper R in the storage section 9, then pulls out the paper P from the roll paper R and closes the cover 8, thus placing the paper in the roll paper printer 1.

[0030] When the cover 8 is closed, the conveyor roller 5, which is mounted on the cover 8, is positioned opposite the head 4 mounted on the housing 7, with the paper P in between. As a result, the conveyor roller 5 abuts against the back side Pb of the paper P, allowing the paper P to be drawn from the roll paper R of the receiving section 9 and conveyed in the conveying direction. Furthermore, the head 4 abuts against the surface Pa of the paper P, thereby enabling printing.

[0031] The conveyor roller 5, located opposite the head 4 and separated from the paper P, is also called the impression roller.

[0032] Furthermore, when the cover 8 is closed, upstream of the conveying roller 5 in the conveying direction, the first paper guide 10 disposed on the cover 8 is positioned opposite the second paper guide 14 disposed on the housing 7, with the paper P positioned in the middle and with a predetermined gap. The first paper guide 10 can abut against the back side Pb of the paper P, and the second paper guide 14 can abut against the surface Pa of the paper P.

[0033] As a result, a first paper path S1 for guiding paper P is formed between the first paper guide 10 and the second paper guide 14, which are opposite each other.

[0034] In addition, the first paper guide 10 and the second paper guide 14 extend in the left and right directions of the roll paper printer 1, which is the paper width direction of the paper P, so as to guide the paper P across the paper width of the paper P.

[0035] The first paper guide 10 has a first surface 11, a second surface 12, and a third surface 13 with different shapes in sequence, starting from upstream and moving downstream in the conveying direction of the paper P.

[0036] Specifically, the first surface 11 is provided with a protruding shape that extends downward toward the direction of the paper P being pulled out from the roll of paper R stored in the storage section 9. The first surface 11 can limit the angle of the paper P from the storage section 9 toward the second surface 12.

[0037] The second side 12 is related to Figure 3 The protruding third paper guide 18 shown is concave in shape. The third surface 13 is convex in shape so as to guide the paper P toward the head 4 and the conveyor roller 5 located above.

[0038] The second paper guide 14 has a fourth surface 15 that is sloping in shape so as to guide the paper P toward the head 4 and the conveying roller 5 located above.

[0039] The fourth surface 15 of the second paper guide 14 is opposite to the third surface 13 of the first paper guide 10, and together with the third surface 13, forms the first paper path S1.

[0040] As will be described later, a mounting surface is formed on the second paper guide 14. Figure 3 The third paper guide 18 shown has a groove 16 and a slot 17 for forming a slit shape for the snap fastener. The groove 16 can also be a hole shape or a slit shape.

[0041] Since the second paper guide 14 is fixed to the housing 7, therefore... Figure 3 As shown, the third paper guide 18 can be fixed to the housing 7 via the second paper guide 14. The third paper guide 18 can be attached to and detached from the housing 7 via the second paper guide 14.

[0042] Alternatively, slot 16 and card slot 17 can be configured such that at least one is directly provided on housing 7. When slot 16 is provided on housing 7, the third paper guide 18 can be attached to and detached relative to housing 7. In this case, switch 6 is also provided on housing 7.

[0043] Furthermore, slot 16 and slot 17 can also be configured such that, instead of being disposed on the second paper guide 14, at least one of them is disposed on a support (not shown), and this support is mounted on the housing 7. In this case, switch 6 is also disposed on the support.

[0044] In this way, the slot 16 and the card slot 17 can be configured to be directly or indirectly disposed on the housing 7.

[0045] The lever 6a of switch 6 can rotate about axis 6b. Inside switch 6, two contacts are made of metal and are configured to be conductive when the two contacts are in contact and to be disconnected when the two contacts are separated.

[0046] exist Figure 2 In, it is shown Figure 3The third paper guide 18 is shown in its state after being removed from the slot 16. The lever 6a of the switch 6 is rotated clockwise, thereby entering the slot 16 of the second paper guide 14. In this state, the two contacts of the switch 6 are separated, thus the switch 6 is turned off. In this way, the switch 6 can send an off signal to the control unit 2 when the third paper guide 18 is not detected.

[0047] On the other hand, such as Figure 3 As shown, when the third paper guide 18 is inserted into the slot 16 and the rod 6a is pressed by the third paper guide 18 and rotated counterclockwise, the two contacts of the switch 6 come into contact and conduct, thus turning the switch 6 on. In this way, the switch 6 can send a signal to the control unit 2 to turn on when the third paper guide 18 is detected.

[0048] Alternatively, the on / off state of switch 6 can be reversed.

[0049] exist Figure 2 In this process, the control unit 2 obtains a shut-off signal from the switch 6. By obtaining the shut-off signal, the control unit 2 can determine that the switch 6 has not detected the third paper guide and that the roll paper printer 1 does not have a third paper guide.

[0050] The storage unit 3 stores the conveying speed corresponding to when switch 6 is off, that is, the conveying speed corresponding to when there is no third paper guide, as setting information. In addition, the storage unit 3 also stores the conveying speed corresponding to when switch 6 is on, that is, the conveying speed corresponding to when there is a third paper guide, as setting information.

[0051] The conveying speed corresponding to when switch 6 is off, i.e., when there is no third paper guide, is, for example, 100 mm / sec, and is stored as setting information in storage unit 3.

[0052] The control unit 2 reads the conveying speed corresponding to when the switch 6 is turned off from the setting information in the storage unit 3. The control unit 2 controls the conveying roller 5 based on the read conveying speed of 100 mm / sec, thereby conveying the paper P.

[0053] The conveying speed of 100 mm / sec when switch 6 is off is faster than the conveying speed of 65 mm / sec when switch 6 detects the conduction of the third paper guide, as described later. This is because the conveying load of paper P is smaller when switch 6 is off, i.e., when there is no third paper guide, compared to when there is a third paper guide.

[0054] Next, refer to Figure 3 The case of having a third paper guide 18 in the roll paper printer 1 will be described in detail.

[0055] like Figure 3 As shown, the third paper guide 18 installed in the roll paper printer 1 has a fifth surface 19, a hook 21 forming a latch, and a protrusion 20.

[0056] The third paper guide 18 is installed onto the second paper guide 14 by inserting the protrusion 20 of the third paper guide 18 into the slot 16 of the second paper guide 14. Conversely, the third paper guide 18 is removed from the second paper guide 14 by pulling the protrusion 20 of the third paper guide 18 out of the slot 16 of the second paper guide 14. In this way, the third paper guide 18 can be attached to and detached relative to the second paper guide 14.

[0057] As described above, the second paper guide 14 is fixed to the housing 7. The third paper guide 18 is mounted on the housing 7 via the second paper guide 14.

[0058] Furthermore, if the slot 16 is provided on the housing 7 instead of the second paper guide 14, the third paper guide 18 can be directly mounted on the housing 7. Additionally, if the slot 16 is provided on a support, the third paper guide 18 can be mounted on the housing 7 via that support.

[0059] In this way, the third paper guide 18 can be configured to be directly or indirectly mounted on the housing 7.

[0060] The hook 21 of the third paper guide 18 and the slot 17 of the second paper guide 14 together form a latch.

[0061] After inserting the protrusion 20 of the third paper guide 18 into the groove 16 of the second paper guide 14, the worker engages the hook 21 of the third paper guide 18 into the groove 17 of the second paper guide 14. As a result, the third paper guide 18 is secured to the second paper guide 14 by a snap-fit. The third paper guide 18 is then secured to the housing 7 via the second paper guide 14 and the snap-fit.

[0062] On the other hand, the staff can also remove the hook 21 of the third paper guide 18 from the slot 17 of the second paper guide 14, thereby removing the third paper guide 18.

[0063] The operator can also secure the third paper guide 18 to the second paper guide 14 by inserting and tightening screws 22 into the screw holes provided on the second paper guide 14. The third paper guide 18 is secured to the housing 7 by screws 22 and via the second paper guide 14. Alternatively, the operator can remove screws 22 to remove the third paper guide 18.

[0064] Alternatively, the third paper guide 18 can be fixed to the second paper guide 14 by at least one of the following: a buckle consisting of a hook 21 and a slot 17, and a screw 22.

[0065] Furthermore, if the slot 17 or screw hole is provided on the housing 7 instead of the second paper guide 14, the third paper guide 18 can be directly fixed to the housing 7 by a snap or screw. Additionally, if the slot 17 or screw hole is provided on the support body, the third paper guide 18 can be fixed to the housing 7 via that support body.

[0066] In this way, the third paper guide 18 can be configured to be directly or indirectly fixed to the housing 7.

[0067] As mentioned above, the closer the paper P is to the core of the roll paper R, i.e., the smaller the diameter of the roll paper R, the stronger its tendency to curl. Receipts and similar items printed on such paper P curl inwards in a coiled manner, thus degrading the quality of the printed product. Furthermore, there is a concern that the curled paper P may get stuck downstream of the conveyor rollers 5 and head 4 in the conveying direction.

[0068] like Figure 3 As shown, the third paper guide 18 has a fifth surface 19 that can abut against the paper P. The fifth surface 19 is configured to protrude in a convex shape toward the second surface 12 of the first paper guide 10, which is concave in shape.

[0069] The fifth surface 19 can also be an arc shape. In this case, the fifth surface 19 is, for example, an arc shape with a diameter of 2 mm. The diameter of the arc shape of the fifth surface 19, 2 mm, is less than 1 / 5 of the diameter of the core of the roll paper R, which is 12 mm to 18 mm.

[0070] The fifth surface 19 of the third paper guide 18 and the second surface 12 of the first paper guide 10 are opposite to each other to form a second paper path S2 for paper P. The second paper path S2 is bent at an acute angle in the opposite direction to the curl of the conveyed paper P in a manner that it abuts against the paper P and corrects the curl of the paper P.

[0071] In this manner, the paper P drawn from the roll of paper R in the receiving section 9 is moved from upstream to downstream in the conveying direction and is corrected for curling via the second paper path S2 formed by the opposing third paper guide 18 and the first paper guide 10. Then, it is conveyed to the conveying roller 5 and the head 4 via the first paper path S1 formed by the opposing second paper guide 14 and the first paper guide 10.

[0072] However, there are situations where the diameter of the roll paper R changes due to the use of paper P, or the roll paper R rolls inside the storage section 9 when the operator carries the roll paper printer 1.

[0073] Even in these cases, the first surface 11 of the first paper guide 10 can abut against the paper P drawn from the roll paper R, thereby limiting the angle of the paper P toward the second paper path S2 in a fixed manner.

[0074] After the paper P abuts against the first surface 11 of the first paper guide 10 and against the fifth surface 19 of the third paper guide 18 on the second paper path S2, it abuts against the third surface 13 of the first paper guide 10 on the first paper path S1.

[0075] In this way, the paper P drawn from the roll of paper R stored in the storage section 9 can, specifically, come into contact with the first surface 11 of the first paper guide 10, the fifth surface 19 of the third paper guide 18, and the third surface 13 of the first paper guide 10 from upstream to downstream in the conveying direction.

[0076] To explain in more detail, after paper P is conveyed at a first angle α from the first surface 11 of the first paper guide 10 to the fifth surface 19 of the third paper guide 18, it is conveyed at a second angle β from the fifth surface 19 of the third paper guide 18 to the third surface 13 of the first paper guide 10. The first angle α and the second angle β are fixed angles.

[0077] Upstream and downstream of the fifth surface 19 of the third paper guide 18, paper P is stably conveyed at a first angle α and a second angle β. Furthermore, the fifth surface 19 abuts against paper P with a predetermined area.

[0078] At this time, the fifth surface 19 of the third paper guide 18 can cause the surface Pa of the paper P conveyed by the conveying roller 5 to bend at an acute angle in the opposite direction of the curling of the paper P at a predetermined angle formed by the first angle α and the second angle β. In addition, the fifth surface 19 of the third paper guide 18 can forcefully rub across the surface Pa of the conveyed paper P with a predetermined area to smooth it out.

[0079] In this manner, the fifth surface 19 of the third paper guide 18 bends in the opposite direction to the curling of the paper P, thereby enabling stable contact at a predetermined angle and a predetermined area formed by the first angle α and the second angle β. Even if the diameter of the roll paper R changes or the roll paper R rolls in the storage section 9, the third paper guide 18 can stably correct the curling of the paper P.

[0080] like Figure 3As shown, the protrusion 20 of the third paper guide 18 is inserted into the slot 16 of the second paper guide 14. The lever 6a of the switch 6 is in contact with the protrusion 20 of the third paper guide 18 and rotated counterclockwise. In this state, the two contacts of the switch 6 are in contact and connected, thus the switch 6 is turned on. In this way, the switch 6 can send a signal to the control unit 2 to turn on when the third paper guide 18 is detected.

[0081] The control unit 2 obtains a conduction signal from the switch 6. By obtaining the conduction signal, the control unit 2 can determine that the switch 6 has detected the third paper guide and that the roll paper printer 1 has a third paper guide.

[0082] The conveying speed stored as setting information in the storage unit 3, corresponding to the condition when switch 6 is on (i.e., when the third paper guide is present), is, for example, 65 mm / sec. The control unit 2 reads the conveying speed corresponding to the condition when switch 6 is on from the setting information in the storage unit 3. The control unit 2 controls the conveying roller 5 according to the read conveying speed of 65 mm / sec, thereby conveying the paper P.

[0083] The 65 mm / sec conveying speed when switch 6 is on is a slower value than the 100 mm / sec conveying speed when switch 6 is off, as described above.

[0084] When switch 6 is on (i.e., when the third paper guide is present), the fifth surface 19 of the third paper guide forcefully rubs against the paper P being conveyed, straightening it while bending it at an acute angle in the opposite direction of its curling. This increases the conveying load on the paper P compared to the case without the third paper guide. By slowing down the conveying speed of the conveying roller 5, the torque required to convey the paper P by the conveying roller 5 can be ensured to cope with the larger conveying load generated by the third paper guide.

[0085] On the other hand, such as Figure 2 As shown, when switch 6 is off, i.e. there is no third paper guide, the conveying load of paper P is smaller compared to the case with the third paper guide. Therefore, even if the conveying speed of conveying roller 5 is increased, the torque of conveying paper P by conveying roller 5 can be ensured.

[0086] For example, when using thick paper P with a thickness of 0.065mm and strong curling, the staff will install the third paper guide 18 on the second paper guide 14 in order to correct the curling, and fix it to the housing 7 by means of buckles, etc.

[0087] Switch 6 detects the third paper guide 18 and sends an on signal to control unit 2. Since control unit 2 receives the on signal from switch 6, i.e., detects the third paper guide 18 via switch 6, it sets the conveying speed of paper P on conveyor roller 5 to 65 mm / sec, thus slowing down the conveying speed compared to when the third paper guide 18 is not detected.

[0088] As described above, the roll paper printer 1, having a third paper guide 18, is in a state where the paper P transport load is relatively large.

[0089] In this case, the roll paper printer 1 slows down the conveying speed of the conveyor roller 5, thereby enabling the paper P to be conveyed while the curl is being corrected.

[0090] On the other hand, if the staff uses thin paper P with a thickness of 0.040 mm and weak curl, they determine that no correction of the curl is required, and remove the third paper guide 18 from the housing 7.

[0091] Since the third paper guide 18 was not detected, switch 6 sends a shut-off signal to control unit 2. Control unit 2, receiving the shut-off signal from switch 6 (meaning the third paper guide 18 was not detected by switch 6), sets the conveying speed of conveyor roller 5 to 100 mm / sec, which is faster than when the third paper guide 18 was detected.

[0092] As described above, the roll paper printer 1, lacking a third paper guide 18, experiences a relatively low paper transport load for the paper P.

[0093] In this case, compared to the case with a third paper guide 18, the roll paper printer 1 can increase the conveying speed of the conveyor roller 5 to transport the paper P, thereby increasing the printing speed. That is, the roll paper printer 1 can increase the printing output.

[0094] As described above, the roll paper printer 1 of this embodiment includes a first paper guide 10, a second paper guide 14 opposite to the first paper guide 10, and a third paper guide 18 capable of contacting the paper P to bend it in the opposite direction of curling. The third paper guide 18 can be attached to and detached from the housing 7 upstream of the second paper guide 14 in the conveying direction.

[0095] When the control unit 2 detects the third paper guide 18 via the switch 6, it can slow down the conveying speed of the paper P conveyed by the conveying roller 5 compared to the case where the third paper guide 18 is not detected.

[0096] Since the conveying load of paper P increases when the third paper guide 18 is installed, the roll paper printer 1 can slow down the conveying speed of the conveying roller 5, thereby conveying paper P while correcting the curl.

[0097] On the other hand, since the conveying load of paper P is reduced when the third paper guide 18 is not installed, the roll paper printer 1 can speed up the conveying speed of the conveying roller 5, thereby increasing the printing output.

[0098] In this way, including when correcting the curling of paper P, the roll paper printer 1 can be set to an appropriate conveying speed corresponding to the conveying load.

[0099] Although the embodiments have been described in detail above with reference to the accompanying drawings, the specific structure is not limited to these embodiments. As long as they do not depart from the spirit of this disclosure, changes, substitutions, deletions, etc., can be made.

[0100] In the above text, although the example of a thermal printhead was used to illustrate the head 4, the printing method is arbitrary. For example, the head 4 could also be an inkjet printhead. In this case, since the inkjet printhead cannot contact the transport roller 5 to clamp and transport the paper P, it is sufficient to mount a driven roller that can clamp and transport the paper P in a manner opposite to the transport roller 5 on the housing 7.

[0101] In the preceding text, although an example of a so-called mechanical switch with a lever 6a serving as the sensor was given, other sensors could also be used. For example, a reflective or transmissive light sensor could also be used. With such a light sensor, the third paper guide 18 could be detected.

[0102] The side of the paper P that abuts against the third paper guide 18 may not be the side to be printed. The roll of paper R is wound with the side of paper P to be printed facing inwards. In this case, the positions of the head 4 and the conveyor roller 5 relative to... Figure 2 as well as Figure 3 The position shown is reversed.

Claims

1. A roll paper printer, comprising: The casing is designed to hold a roll of paper that is wound with one side facing outwards. A conveyor roller that draws the paper out of the roll and conveys it in the conveying direction; A first paper guide is capable of abutting against the other side of the paper upstream of the conveying roller in the conveying direction; A second paper guide is positioned opposite the first paper guide and is capable of abutting against one side of the paper; The third paper guide is detachable and can abut against one side of the paper upstream of the second paper guide in the conveying direction to bend it. A sensor capable of detecting the third paper guide; The control unit, when the third paper guide is detected by the sensor, slows down the conveying speed of the paper conveyed by the conveying roller, compared to when the third paper guide is not detected.

2. The roll paper printer as described in claim 1, wherein, The roll paper printer includes: The head, which is printed on the paper; The cover, which opens and closes the shell. The conveying roller is disposed on either the housing or the cover. The head is disposed on either the housing or the cover. The first paper guide is disposed on the cover. The second paper guide is disposed on the housing. The third paper guide can be detached from the housing.

3. The roll paper printer as described in claim 1 or claim 2, wherein, The first paper guide has, starting from upstream in the conveying direction, a first surface, a second surface, and a third surface with different shapes from each other. The second paper guide faces the third surface of the first paper guide, thereby forming the first paper path. The third paper guide faces the second surface of the first paper guide, thereby forming a curved second paper path. The paper drawn from the roll can abut against the first surface of the first paper guide.

4. The roll paper printer as described in claim 1, wherein, The third paper guide has a protrusion. The housing has a groove. The third paper guide is inserted into the slot via the protrusion, thereby enabling it to be mounted on the housing.

5. The roll paper printer as described in claim 1, wherein, The third paper guide has a latch. The housing has a slot. The hook and the slot together form a detachable buckle. The third paper guide is fixed to the housing by engaging with the slot of the housing via the hook.

6. The roll paper printer as described in claim 1, wherein, The third paper guide is fixed to the housing in a detachable manner by screws.

Images