Printer

Abstract

To provide a new printer that can appropriately perform skew correction, even in a state where physical guide for a paper roll cannot be expected.SOLUTION: A printer comprises: a printer main body PB that holds paper 1 fed from a paper roll R loaded on a paper feeding roller 2, performs printing on the paper 1 at a printing position PL while making a main conveying roller 3 convey the paper, cuts a printed region A1 with a longitudinal cutter 13 and ejects the region; a longitudinal cutting unit SU that introduces the paper 1 being ejected, through a longitudinally cutting guide 11 in a width direction and cuts the paper with the longitudinal cutter 13 while making an auxiliary conveying roller 12 hold the paper; and a control part CU that controls the printer main body PB and the longitudinally cutting unit SU. Further, the control part CU is configured to execute skew correction control by which the auxiliary conveying roller 12 is made to hold the paper 1 and the paper supply roller 2 is driven in a taking-up direction of the paper 1 with the main conveying roller 3 opened, so that loosening of the paper 1 is tensed up between a tip portion 1 (S) of the paper and the paper roll, and the auxiliary conveying roller 12 in a state of tension is released so as to correct skew of the paper 1.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a printer that can output a narrow-width mini-print by cutting a paper widthwise at a required position with a vertical cutter. [Background technology]

[0002] Conventionally, a printer of this type is known, as disclosed in Japanese Patent Application Laid-Open No. 2003-233696. As shown in FIG. 8, this printer comprises a paper feed roller 2 which is loaded with a paper roll R and which pays out the paper 1 towards the printing position PL, a main transport means 3 which transports the paper 1 paid out from the paper roll R at a predetermined speed, a pair of supply side bobbins 5a and take-up side bobbins 5b which are arranged to supply the ribbon 4 together with the paper 1 to the printing position PL, a platen roller 6 which is arranged below the paper 1 at the printing position PL, a print head 7 which is arranged above the paper 1 so as to be able to come into contact with and separate from the platen roller 6 and which prints on the paper 1 with the paper 1 and ink ribbon 4 pressed against the platen roller 6, a paper discharge means 8 which clamps the paper 1 and discharges it, and a cross cutter 9 which cuts the paper 1 to the required length before discharge.

[0003] As shown in Figure 9, the paper feed roller 2 has a shaft portion 2a and disk-shaped paper guides 2b on both sides thereof. The paper roll R is loaded with its center supported by the shaft portion 2a and its both sides sandwiched between the paper guides b.

[0004] Printing is performed while the paper 1, once unwound from the paper roll R in the paper discharge direction (arrow A direction in FIG. 8), is transported by the main transport means 3 in the counter paper discharge direction (printing B direction) that is the opposite direction to the paper discharge direction.

[0005] After printing, the paper 1 is cut by the horizontal cutter 9. The cut paper 1 is discharged by the auxiliary conveying means 12.

[0006] In addition, this printer is equipped with a vertical cutter 13 downstream of the horizontal cutter 9 in order to diversify print sizes. As shown in Figures 8 and 10, the vertical cutter 13 cuts the required portion of the paper widthwise, and of the cut paper 1, the area that will be printed and become the printed matter (printed matter) U is transported to a print outlet, while the unprinted area is transported to a trash can as unnecessary part V. In the figures, reference numeral 14 denotes a separation mechanism that separates the unnecessary part V from the printed matter U and changes the route to guide it to the trash can. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-104655 A Summary of the Invention [Problem to be solved by the invention]

[0008] Conventionally, rolled plain paper of normal thickness has been used as the paper 1. The size of the roll paper is generally such that a predetermined number of sheets (e.g., around 350 images) can be printed when counted in normal paper sizes (e.g., A4 size).

[0009] On the other hand, printers with the function of the vertical cutter 13 can reduce the width of the printed matter, so they are also used for mini print applications such as 3.25 inches x 2.75 inches. For mini print applications, thick paper produces a better appearance, like instant photos, so having the ability to handle thick paper is extremely important in terms of improving the commercial value of the printer.

[0010] However, if the capacity of the consumable paper roll R, i.e., the number of prints, remains the same as before, and the paper becomes thicker, the diameter of the paper roll R becomes larger as shown in FIG. 11 compared to the diameter of the paper roll R of plain paper shown in FIG.

[0011] Conventionally, this type of paper roll R is set between the left and right paper guides 2b, 2b, and the paper guide 2b acts as a physical guide to unwind the paper 1. However, as shown in Figure 11, when the diameter of the paper roll R becomes large, the paper roll R protrudes from the paper guide 2b, and the paper 1 is unwound from a position that is not guided by the paper guide 2b. As a result, the unwinding position of the paper 1 shifts left and right, and the paper 1 is meandered when it is wound onto the paper roll R.

[0012] As a result, as shown by the arrow in Figure 11, the paper skews between the tip of the paper and the paper roll payout position, and the paper 1 also skews at the position of the vertical cutter 13 shown in Figure 10, resulting in a new problem in that the positional accuracy of the slit S formed at this position is reduced.

[0013] An object of the present invention is to provide a new printer that is capable of performing appropriate skew correction even in a situation where physical guidance by a paper guide for the paper roll cannot be expected. [Means for solving the problem]

[0014] In order to achieve the above object, the present invention provides the following means.

[0015] That is, the printer of the present invention has a printer body which holds paper fed from a paper roll loaded on a paper feed roller, transports it with a main transport roller, prints on the paper at a printing position, cuts the printed paper with a horizontal cutter and discharges it, a vertical cutting unit which introduces the paper in the discharge process via a vertical cutting guide in the width direction, holds it with auxiliary transport rollers and cuts it with the vertical cutter, and a control unit which controls the printer body and the vertical cutting unit, The auxiliary conveying rollers are provided in pairs upstream and downstream of the longitudinal cutting cutter,The control unit is configured to perform skew correction control in which the auxiliary transport roller clamps the paper and the main transport roller is released while driving the paper feed roller in the paper winding direction, thereby tensioning the slack in the paper between the leading end of the paper and the paper roll, and the auxiliary transport roller is released from the tensioned state to correct the skew of the paper.

[0016] In this way, the paper can be tensioned by winding up the slack between the paper tip and the paper roll with the paper roll while the leading edge of the paper is positioned in the width direction within the vertical cutting guide and fixed by the auxiliary transport roller. After that, when the auxiliary transport roller is released, the difference in the balance of tension between the left and right sides of the paper is released, and the force of the paper trying to return to the correct position can be used to correct the skew. In order to utilize this phenomenon, it is effective to stretch the paper at two points as far apart as possible, so it is effective to stretch the paper between the leading edge of the paper and the roll paper. In particular, the narrow vertical cutting guide can be expected to serve as a fulcrum for the paper when the skew amount of the paper is large when the paper is stretched, and to suppress the vibration of the paper when the auxiliary transport roller is released even if the skew amount is small. Therefore, it is possible to correct the skew even when using thick paper with a large diameter, and the positional accuracy of the width direction of the slit formed by the horizontal cutting cutter can be improved, thereby realizing a highly accurate vertical cutting slit.

[0017] In this case, the paper feed roller may be driven in the paper winding direction to tension the paper, and then the paper may be clamped by the main transport rollers to maintain the tension on the paper when the auxiliary transport rollers are released.

[0018] Even if the paper is tensioned at two points, the leading edge of the paper and the main transport roller, a sufficient distance can be secured to correct the skew.

[0019] In particular, it is preferable that the paper feed roller is provided with paper guides at positions that sandwich both sides of the paper roll, and that a paper roll having a diameter larger than that of the paper guides is mounted on the paper feed roller.

[0020] Since the present invention is capable of correcting skew without relying on a paper guide, skew correction is theoretically possible without using a paper guide at all; however, by employing a paper guide, physical positioning in the width direction is possible for roll paper below a certain diameter, improving the skew correction function.

[0021] When the paper roll is initially loaded, if a preparatory operation is performed to cut off the outer skin portion of the paper, which corresponds to one periphery of the paper, it is preferable that the skew correction control is executed during the preparatory operation.

[0022] During initial loading, it is highly likely that the position at which the paper is fed from the paper roll is skewed, so it is effective to apply the skew correction control of the present invention to the above preparatory operations.

[0023] When color printing on one printing area is performed by transporting the paper in the forward and reverse directions multiple times, it is desirable that the skew correction control be performed each time color printing on one printing area is completed, or each time color printing on multiple printing areas is completed.

[0024] In the color printing process, skew can occur even when the paper is moving back and forth, so it is effective to apply the skew correction control of the present invention when color printing is completed for one or more printing areas (screens).

[0025] It is desirable that the drive system of the vertical slicing unit is independent of the drive system of the printer body, and that the control unit performs necessary synchronization of the drive system of the vertical slicing unit and the drive system of the printer body by control.

[0026] By making the drive system independent in this way, the vertical cutting unit can be installed in an existing printer in a space-saving and inexpensive manner. As a secondary effect of driving the vertical cutting unit and the printer body independently, it becomes possible to realize the skew correction operation of the present invention. In other words, if the drive system of the vertical cutting unit is connected to the drive system of the printer body, the skew correction of the present invention cannot be realized or a special mechanism must be interposed, but this invention eliminates such concerns.

[0027] It is preferable that the vertical slicing unit is later attached to the printer body.

[0028] Even if it is a retrofit, or perhaps because it is a retrofit, the drive system is necessarily independent. In other words, because it is a retrofit, it is easier to achieve skew correction by software. Effect of the Invention

[0029] According to the present invention as described above, it is possible to provide a new and useful printer that is capable of performing appropriate skew correction even in a situation where physical guidance by a paper guide cannot be expected for the paper roll. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic side view showing a configuration of a printer according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic view of the internal configuration of FIG. 1 from above along the paper. [Diagram 3] FIG. 4 is a diagram showing the relationship between the ink ribbon and the paper fed to the printing position. [Figure 4] Cross-sectional view taken along line IV-IV in FIG. 2. [Diagram 5] FIG. 3 is a diagram showing a modification of FIG. 2. [Figure 6] 5A to 5C are explanatory diagrams of skew correction control according to the embodiment. [Figure 7] FIG. 4 is a flowchart showing a procedure of skew correction control according to the embodiment. [Figure 8] FIG. 1 is a schematic side view showing the configuration of a conventional printer. [Figure 9] FIG. [Figure 10] FIG. 4 is a diagram showing the vertical cutting function of the printer. [Figure 11] FIG. 10 is a diagram corresponding to FIG. 9 and explains a defect in a conventional printer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0032] FIG. 1 is a schematic side view showing the configuration of the printer of this embodiment, FIG. 2 is a schematic view of the internal configuration of FIG. 1 from above along the paper 1, and FIG. 3 is a diagram showing the relationship between the ink ribbon 4 fed into the printing position PL and the paper 1.

[0033] The printer P includes a printer main body PB and a vertical cutting unit SU.

[0034] The printer main body PB is equipped with a paper feed roller 2 that is loaded with a paper roll R and that pays out the paper 1 towards the printing position PL, a main transport roller 3 that serves as a main transport means that transports the paper 1 paid out from the paper roll R at a predetermined speed, a pair of supply side bobbins 5a and take-up side bobbins 5b that are arranged to supply the ribbon 4 together with the paper 1 to the printing position PL, a platen roller 6 that is arranged below the paper 1 at the printing position PL, a print head 7 that is arranged to be able to move toward and away from the platen roller 6 from above the paper 1 and prints on the paper 1 with the paper 1 and ink ribbon 4 pressed against the platen roller 6, a paper discharge roller 8 that serves as a paper discharge means that clamps the paper 1 and discharges it, a cross cutter 9 that cuts the paper 1 to the required length before discharge, and a control unit CU that controls the transport of the paper 1 and the supply of electricity to the print head 7.

[0035] 2, the paper feed roller 2 has disk-shaped paper guides 2b on both sides of a shaft 2a, and the paper roll R is supported at its center by the shaft 2a and is loaded onto the paper feed roller 2 with both sides sandwiched between the paper guides 2b. The paper feed roller 2 is connected to a motor (not shown), and is driven when it is necessary to pay out or rewind the paper 1 from the paper roll R.

[0036] The main transport rollers 3 shown in Fig. 1 are made up of a feed roller 3a and a main pinch roller 3b. The feed rollers are connected to a motor (not shown) independent of the paper feed roller 2, and the main pinch roller 3b can move toward and away from the feed roller 3a via the paper 1, and by pressing against it, the paper 1 is pinched between the feed roller 3a and the main pinch roller 3b to transmit a transport force to the paper 1. The feed roller 3a has the function of driving in forward and reverse directions to transport the paper 1 at a predetermined speed.

[0037] The bobbins 5a, 5b are arranged on either side of the printing position PL along the transport direction of the paper 1, and an unused ribbon 4 is fed from the supply side bobbin 5a to the printing position PL, and the ribbon 4 used for printing is wound up onto the take-up side bobbin 5b.

[0038] As shown in Figure 3, the ink ribbon 2 has repeated areas in the length direction where dyes of Y (yellow), M (magenta), C (cyan), and OP (overcoat) are applied. Hereinafter, the color print layer printed by the ink ribbon 2 will be referred to as "CLR."

[0039] The print head 7 shown in FIG. 1 is arranged so as to be able to rise and fall relative to the platen roller 6, and in a pressure-contact state heats the link ribbon 4 to transfer ink to the paper 1 based on print information (image information) sent from the control unit CU.

[0040] The paper discharge rollers 8 are made up of a transport roller 8a and a pinch roller 8b. The transport roller 8a is connected to a motor (not shown) independent of the paper feed rollers 2, etc., and the pinch roller 8b can move toward and away from the transport roller 8a via the paper 1. By pressing the pinch roller 8b against the transport roller 8a, the paper 1 is pinched between the transport roller 8a and the pinch roller 8b, transmitting a transport force to the paper 1 in the paper discharge direction.

[0041] As shown in FIG. 2, the lateral cutter 9 cuts the paper 1 in a direction perpendicular to the conveying direction by cutting the paper 1 widthwise.

[0042] The control unit CU is composed of a normal microcomputer unit equipped with a CPU, memory, and interface, and the memory stores programs and data necessary to execute the operation of the printer, including the skew correction operation of the present invention, through control of the printer main body PB, vertical cutting unit SU, etc. As a basic control during printing, the paper 1 that has been once unwound from the paper roll R in the paper feed direction (arrow A direction in Fig. 1) is transported together with the ink ribbon 4 by the main transport rollers 3 in the printing direction (arrow B direction in Fig. 1), which is the opposite direction to the discharge direction, to the printing position PL, where printing is performed on the required parts of the paper 1 based on printing information provided from the outside.

[0043] As shown in Fig. 3, the paper 1 to be printed has the same printing area transported back and forth between the print start position 1 (P) and the print end position 1 (Q), and at the start of each printing, the leading edge of the ink ribbon 4 is switched between Y, M, C, and OP as shown in (a) to (d) in the figure, and the print head 7 is lowered while overlapping with the paper 1 (P) at the print start position, and the color print layer CLR and overcoat layer OP are printed while the paper 1 and the ink ribbon 4 are transported simultaneously. Until the overcoat layer OP is printed, the print head 7 is raised after printing is completed, and only the paper 1 is returned from the print end position 1 (Q) to the print start position 1 (P), leaving the ink ribbon 4 behind.

[0044] After printing up to the overcoat layer OP has been completed for one printing area, the paper 1 is sent out toward the paper output 10 of the printer body PB shown in FIG. 2 by the paper output rollers 8 shown in FIG. 1, and at a predetermined sending position, the cross cutter 9 operates in the paper width direction to cut between the printed area A1 and the unprinted area A2.

[0045] On the other hand, the vertical cutting unit SU shown in Figures 1 and 2 is attached to the printer main body PB as an add-on, and is equipped with a vertical cutting guide 11 that receives the paper 1 discharged from the paper discharge port 10 of the printer main body PB, a pair of auxiliary conveying rollers 12 that serve as auxiliary conveying means that convey the paper 1 introduced from this vertical cutting guide 11 within the vertical cutting unit SU, and a vertical cutting cutter 13 located between this pair of auxiliary conveying rollers 12.

[0046] The vertical cutting guide 11 is tapered so as to gradually narrow along the conveying direction in order to position the paper 1 in the width direction while receiving the paper 1. The printer body PB also has a paper guide 11', but the vertical cutting guide 11 of the vertical cutting unit US is narrower than the paper guide 11' of the printer body PB.

[0047] The auxiliary transport rollers 12 include an auxiliary drive transport roller 12a located below the paper 1, and an auxiliary pinch roller 12b located above the paper and capable of moving toward and away from the auxiliary drive transport roller 12a. The auxiliary drive transport roller 12a is connected to a motor independent of the feed roller 3a of the printer main body PB, the transport roller 8a of the paper discharge roller 8, and the paper feed roller 2, and the lifting motor for the auxiliary pinch roller 12b is also connected to a motor independent of the main pinch roller 3b of the printer main body PB, the pinch roller 8b of the paper discharge roller 8, and the lifting motor for the print head 7.

[0048] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. Fig. 4(a) shows how an area (printed matter) U that becomes a printed matter after cutting by the vertical cutter 13 is led to a printed matter outlet, and Fig. 4(b) shows how an unnecessary part V that becomes a waste and is not used for printing after cutting by the vertical cutter 13 is led to a waste bin by a separation mechanism 14. The vertical cutter 13 cuts the paper 1 vertically between a lower cutter 13a on the lower surface side of the paper and an upper cutter 13b on the upper surface side of the paper to form a slit S, and the lower cutter 13a and the upper cutter 13b are held by holders Ha and Hb, respectively. The holders Ha and Hb are capable of moving the cutters 13a and 13b in synchronization between a standby position 13(A) that does not interfere with the passage of the paper 1 as shown in Fig. 2 and a required position 13(B) in the paper width direction where vertical cutting is required. The movement from the standby position (A) to the required position 13 (B) is performed before the sheet 1 reaches the position where it needs to be cut lengthwise.

[0049] The illustrated example has one vertical cutter 13, but it is also possible to provide two sets of vertical cutters 13 as shown in FIG. 5, and configure the paper 1 to be cut into three pieces by moving each of them from a standby position 13(A) to a different cutting position 13(B).

[0050] The position of the slit S generated by the vertical cut is based on externally provided printing information (e.g., photo print information). That is, when the printing information determines the size of the print image in inches and the location of the print area on the paper 1, the position of the slit S for vertical cutting is specified, and the control unit CU moves the vertical cutter 13 to the position of the slit S and executes the vertical cut.

[0051] After being cut by the vertical cutting cutter 13, the area (printed matter) U which becomes the printed matter with the required printing applied to the printing area passes through a regular route and is finally led out to the printed matter outlet of the vertical cutting unit SU, as shown in Figures 2 and 4(a). On the other hand, in order to send the unnecessary part V which becomes waste to a route for storing it in a waste bin, this printer is provided with a separation mechanism 14 which changes the discharge route while separating the unnecessary part V from the area U which becomes the printed matter, as shown in Figures 2 and 4(b).

[0052] As shown in Figures 2, 4(b) and 10, the separation mechanism 14 is attached to an upper holder Hb that holds the upper cutter 13b downstream of the vertical cutter 13, and is arranged so as to press a position a predetermined distance in the width direction from the position where the vertical cut is made, and operates together with the upper cutter while maintaining this positional relationship. The separation mechanism 14 is configured to move from a position shown by an imaginary line in Figure 4(b) where it does not interfere with the paper 1 to a position where it presses the paper 1 downward by rotating around an axis m. The contact surface of the separation mechanism 14 with the paper 1 is a smoothly curved surface that smoothly guides the paper 1 downward. As a result, the unnecessary part V is separated from the area (printed matter) U that will become the printed matter, and is guided in the direction toward the trash can.

[0053] During vertical cutting by the vertical cutter 13, when the end of the printed area A1 shown in Fig. 2 reaches the position of the horizontal cutter 9, the horizontal cutter 9 cuts between the printed area A1 and the unprinted area A2. After that, the remaining vertical cut is completed while the paper 1 is fed by the auxiliary transport rollers 12. As a result, the area that will become the printed matter (printed matter) U is cut out as a mini print.

[0054] In Figs. 1 and 2, reference numerals 15 and 15' denote sensors for detecting the leading edge of the paper.

[0055] In the above configuration, in order to address the problem of the paper guide 2b being unable to physically correct the skew of the paper 1 due to the thickening of the paper roll R shown in Figure 11, this embodiment is configured to perform skew correction by the control unit CU using the auxiliary transport roller 12 in the vertical cutting unit SU shown in Figure 1, the paper feed roller 2 in the printer body PB, and the vertical cutting guide 11 in the vertical cutting unit SU shown in Figure 2.

[0056] The basic method of skew correction control is to clamp the paper 1 with the auxiliary transport rollers 12, and drive the paper feed rollers 2 in the direction of winding the paper 1 while the main transport rollers 3 are released, as shown in Figure 6(a). This tensions the slack in the paper 1 between the paper leading edge 1(S) and the paper roll R. Then, the auxiliary transport rollers 12 are released. This also corrects any skew in the paper 1.

[0057] The skew correction procedure will be described below. Skew correction control is executed when the paper roll R is replaced and when printing on one or more print areas on the paper 1 is completed.

[0058] The procedure for replacing the paper roll R is as follows:

[0059] First, a cover (not shown) of the printer main body PB shown in Fig. 1 is opened. In this state, the print head 7, the main pinch roller 3b of the main transport roller 3, the auxiliary pinch roller 12b of the auxiliary transport roller 12, and the pinch roller 8b of the discharge roller 8 are all raised up, unlike the state shown in Fig. 1. Then, the paper roll R is set, and the leading edge 1(S) of the paper is unwound from the paper roll R and fed manually to the paper discharge outlet 10 of the printer main body PB shown in Fig. 2, and further fed through the vertical cutting guide 11 at the entrance of the vertical cutting unit SU to between the pair of auxiliary transport rollers 12, 12. The control unit CU detects the insertion of the paper 1 by the sensor 15'.

[0060] Next, the cover is closed. The control unit CU detects that the cover has been closed. After that, the main transport rollers 3 are driven to pull the leading edge 1(S) of the paper back to near the exit of the printer main body PB, where the sensor 15 detects the leading edge 1(S) of the paper. Information on the leading edge position of the paper 1 is necessary to cut the soiled outer circumference of the paper 1, which is the surface layer.

[0061] Thereafter, the paper 1 is straightened for skew while the transverse cutter 9 cuts the paper 1 at a required position and ejects it, completing preparation for printing.

[0062] The skew correction control is performed according to the procedure shown in the flowchart in FIG. 7. First, the main transport roller 3 moves the paper leading edge 1(S) into the vertical cutting unit SU (step S1), and the auxiliary pinch roller 12b constituting the auxiliary transport roller 12 is lowered to pinch the paper 1 between it and the transport roller 12a below it (step S2). Next, the main pinch roller 3b constituting the main transport roller 3 is raised (step S3), and the paper feed roller 2 is driven in the winding direction (step S4). This removes the slack in the paper 1 located between the paper leading edge 1(S) and the paper roll R shown in FIG. 6(a). At this time, small skews and slack occurring between the rollers can be removed, and the attitude of the paper 1 can be corrected on a small scale.

[0063] After that, when the auxiliary pinch roller 12b is raised (step S6), the imbalance of tension on the left and right sides of the paper 1 is released, and the force of the paper 1 trying to return to the correct position can be used to correct the skew. To utilize this phenomenon, it is effective to stretch the paper 1 at two points as far apart as possible, so it is effective to stretch the paper 1 between the paper tip 1(S) and the paper roll R. In particular, the presence of the narrow vertical cutting guide 11 can be expected to serve as a fulcrum for the paper 1 when the amount of skew of the paper 1 is large when the paper 1 is stretched, or to suppress the vibration of the paper 1 when the auxiliary pinch roller 12b is raised even if the amount of skew is small. After the skew is corrected, the main pinch roller 3b is lowered to move to the next conveyance.

[0064] In this case, the main pinch rollers may be lowered (step S5) before the auxiliary pinch rollers 12b are raised in step S6. This is because even if the paper 1 is tensioned at two points, the paper leading edge 1(S) and the main transport rollers 3, a sufficient distance can be secured to correct the skew.

[0065] The process of tensioning the paper 1 between the paper leading edge 1(S) and the paper roll R (or between the paper leading edge 1(S) and the main transport rollers 3) to remove slack as described above leads to small-scale correction of the paper 1 posture, and can also be performed when the pinch rollers 3b of the main transport rollers 3 are lowered to continue printing, or when the paper leading edge 1(S) is cut off to align the paper leading edge. By performing this type of control, small-scale corrections that frequently reduce the effects of skew are repeated, making it possible to reduce the cumulative amount of skew for each operation. This also makes it possible to reduce the number of times the auxiliary transport rollers 12 are released and the process of re-gripping is performed as described above.

[0066] After step S6 is performed, the paper is conveyed across the cut portion to the cutting position of the cutter 9 in order to cut off a portion a predetermined distance from the leading edge 1(S), and then the cutting is performed. Before cutting, the paper 1 is conveyed by the main conveyance rollers 3 and the paper discharge rollers 8, and after cutting, the paper 1 is conveyed by the auxiliary conveyance rollers 12. In this embodiment, the surface portion of the paper roll R is cut across multiple times (six times). After the sixth cut is completed, the pinch roller 12b of the auxiliary conveyance rollers 12 is raised and the paper 1 is moved to the position of the sensor 15 by the main conveyance rollers 3 to detect the leading edge 1(S) of the paper, and then steps S1 to S6 in FIG. 7 are performed to enter a print standby state.

[0067] Thereafter, when a print command is input, the control unit CU starts the printing operation.

[0068] The basic printing operation involves first unrolling the paper 1 from the paper roll R in the paper discharge direction (direction A in Figure 1), and then transporting the paper 1 in the printing direction (direction B in Figure 1), which is the opposite direction to the paper discharge direction, by the main transport rollers 3, while printing Y, M, C, and OP at the printing position PL.

[0069] When printing is complete, vertical and horizontal cuts are performed to complete printing of one printing area. If vertical cuts are not performed, the vertical cut process is omitted.

[0070] The above-mentioned skew correction control is also performed in this printing process. In this embodiment, the control unit CU is configured to execute the above steps S1 to S6 every time printing of two printing areas (e.g., two pages of printing screen) is completed. Before and after the skew correction control, the paper leading edge 1(S) is detected.

[0071] As described above, the printer of this embodiment has a printer main body PB that clamps the paper 1 fed from the paper roll R loaded on the paper feed rollers 2, transports it with the main transport rollers 3, prints on the paper 1 at the printing position PL, and cuts the printed paper 1 with the cross-cut cutter 9 and discharges it, a vertical cutting unit SU that introduces the paper 1 during discharge via the width-wise vertical cutting guide 11, clamps it between the auxiliary transport rollers 12, and cuts it with the vertical cutting cutter 13, and a control unit CU that controls the printer main body PB and the vertical cutting unit SU.

[0072] The control unit CU is configured to perform skew correction control in which the auxiliary conveying rollers 12 clamp the paper 1 and the main conveying rollers 3 are released while driving the paper feed rollers 2 in the winding direction of the paper 1 to tension the slack in the paper 1 between the paper leading edge 1(S) and the paper roll R, and the auxiliary conveying rollers 12 are released from the tensioned state to correct the skew of the paper 1.

[0073] In this way, the paper 1 can be tensioned by winding up the slack in the paper 1 between the paper tip 1(S) and the paper roll R with the paper roll R while the paper tip 1(S) is positioned in the width direction within the vertical cutting guide 11 and fixed by the auxiliary transport roller 12. After that, when the auxiliary transport roller 12 is released, the difference in the balance of tension between the left and right sides of the paper 1 is released, and the force of the paper 1 trying to return to the correct position can be used to correct the skew. In order to utilize this phenomenon, it is effective to tension the paper 1 at two points as far apart as possible, so it is effective to tension the paper 1 between the paper tip 1(S) and the paper roll R. In particular, the presence of the narrow vertical cutting guide 11 can be expected to serve as a fulcrum for the paper 1 when the skew amount of the paper 1 is large when the paper 1 is tensioned, and to suppress the vibration of the paper 1 when the auxiliary transport roller 12 is released even if the skew amount is small. Therefore, even when using thick paper 1 with a large diameter, skew can be corrected, and the positional accuracy in the width direction of the slit formed by the vertical cutter 13 can be improved, thereby realizing highly accurate vertical slits.

[0074] In particular, the paper feed roller 2 of this embodiment is provided with paper guides 2b at positions that sandwich both sides of the paper roll R, and the paper feed roller 2 is fitted with a paper roll R having a larger diameter than the paper guides 2b.

[0075] In this embodiment, skew correction is possible without relying on the paper guide 2b, and therefore skew correction is theoretically possible without using the paper guide 2b at all. However, by using the paper guide 2b to position the paper roll R with a diameter of a certain value or less in the width direction, the skew correction function can be improved.

[0076] Furthermore, in this printer, a preparatory operation is performed when the paper roll R is initially loaded, in which the outer periphery of the paper 1, that is, the surface portion, is cut off, and the skew correction control is executed during this preparatory operation.

[0077] During initial loading, it is highly likely that the payout position from the paper roll R is skewed, so it is effective to apply the skew correction control of this embodiment to the above preparatory operation.

[0078] In addition, in this printer, color printing in one printing area is performed by conveying the paper 1 in the forward and reverse directions multiple times, and skew correction control is performed each time color printing in multiple printing areas is completed. Of course, skew correction control may be performed each time printing in one printing area is completed.

[0079] In a color printing process, skew may occur even when the paper 1 is moving back and forth, so it is effective to apply the skew correction control of this embodiment to the printing process.

[0080] In this printer, the drive system of the vertical slicing unit SU is independent of the drive system of the printer body PB, and the control unit CU is configured to control and perform the necessary synchronization of the drive system of the vertical slicing unit SU and the drive system of the printer body PB.

[0081] By making the drive systems independent in this way, the vertical slicing unit SU can be installed in an existing printer in a space-saving and inexpensive manner. As a secondary effect of independently driving the vertical slicing unit SU and the printer body PB, it is possible to realize the skew correction operation of this embodiment. In other words, if the drive system of the vertical slicing unit SU is connected to the drive system of the printer body PB, the skew correction of this embodiment cannot be realized or a special mechanism must be interposed, but this embodiment eliminates such concerns.

[0082] The vertical slicing unit SU of this printer is attached to the printer body PB.

[0083] In this way, even if it is a retrofit, or perhaps because it is a retrofit, the drive system is necessarily independent. In other words, because it is a retrofit, skew correction by software is easy to achieve.

[0084] Although one embodiment of the present invention has been described above, the specific configuration of each part is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0085] 1. Paper 2...Feed roller 2b…Paper guide 3...Main transport roller 9...Cross cutting cutter 11...Vertical cutting guide 12...Auxiliary conveying roller 13...Vertical cutter A1: Printed area CU: Control unit PB: Printer body PL…Print position R…Paper roll SU: Vertical cutting unit

Claims

1. A printer having a printer body which holds paper fed from a paper roll loaded on a paper feed roller, conveys the paper with a main conveyance roller, prints on the paper at a printing position, cuts the printed paper with a horizontal cutter and discharges it, a vertical cutting unit which introduces the paper in the discharge process via a vertical cutting guide in the width direction, holds the paper with an auxiliary conveyance roller, and cuts it with the vertical cutter, and a control unit which controls the printer body and the vertical cutting unit, The auxiliary conveying rollers are provided in pairs upstream and downstream of the longitudinal cutting cutter, a control unit that performs skew correction control to tension the slack in the paper between the leading edge of the paper and the paper roll by driving the paper feed roller in the paper winding direction while the auxiliary transport roller is clamping the paper and the main transport roller is released, and to correct the skew of the paper by releasing the auxiliary transport roller from the tensioned state.

2. 2. The printer according to claim 1, wherein the paper feed roller is driven in the paper winding direction to tension the paper, and then the paper is clamped by the main transport rollers, thereby maintaining the tension on the paper when the auxiliary transport rollers are released.

3. 3. The printer according to claim 1, wherein the paper feed roller is provided with paper guides at positions that sandwich both sides of the paper roll, and a paper roll having a diameter larger than that of the paper guides is attached to the paper feed roller.

4. A printer according to any one of claims 1 to 3, wherein when color printing on one printing area is performed by transporting the paper in the forward and reverse directions multiple times, the skew correction control is performed each time color printing on one printing area is completed, or each time color printing on multiple printing areas is completed.

5. 5. The printer according to claim 1, wherein the vertical cutting unit is attached to the printer body later.

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