JP2002225363A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain perpendicularity of a front edge of a roll paper and to eliminate a shift of a printing position in a paper conveyance direction in the printing on a front face and a rear face of a paper when using a perfecting printer. SOLUTION: There is disclosed a printer wherein the printing is performed on a roll paper 110 at a printing section, and the paper 110 is cut by a cutter 35 by each printing unit. A paper detector 61 and a paper tip detector 64 are disposed on different positions in a conveyance direction of a paper 110 to be separated in a widthwise direction of the paper 110. The printer is provided with a control means wherein a deviation in perpendicularity of the front end of the paper is detected, in such a manner that a difference in time or in distance from the detection of the roll paper 110 by the paper detector 61 to the detection by the paper tip detector 64 is compared with an already-known value. When the deviation is outside of an allowable range, the tip section of the roll paper 110 is cut by the cutter 35 to eliminate the deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus using continuous paper, and in particular, to eliminate the bend (skewed state) at the leading edge of the continuous paper and to align the leading edges of the printing area on both sides of the paper using two printers. The present invention relates to a printing device suitable for printing.

[0002]

2. Description of the Related Art Conventionally, there has been a printing apparatus for printing on both sides of continuous paper using two printers, which has a reversing mechanism for reversing the front and back of a sheet between a first printer and a second printer. (For example, JP-A-56-99585). This double-sided printing apparatus prints on one side (first side) of continuous paper by a first printer, reverses the front and back of the continuous paper by a reversing mechanism, and then reverses the other side of the continuous paper (second side). ) Is printed by the second printer.

One of the problems in such a duplex printing apparatus is how to accommodate two printers compactly in the same housing to reduce the size of the apparatus. The use of the same configuration is advantageous in terms of manufacturing cost and maintenance.

In Japanese Patent Application Laid-Open No. 7-237336, an intermediate buffer device is provided between a first printer and a second printer having the same configuration to absorb a difference in paper feed speed between the two printers. As shown in FIG. 6, there is shown a configuration including a reversing mechanism 101 in which continuous paper enters obliquely and exits obliquely. However, since the intermediate buffer device is provided on the way, the transport path of the continuous paper between the first printer and the second printer tends to be long and complicated. The continuous paper 1 that has passed through the reversing mechanism 101
03 has a tendency to bend in an oblique direction, and in the mechanism, the continuous paper may be swayed right and left, and the edge may be broken or a jam may occur.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present inventors have arranged a first printer and a second printer having the same structure in the same housing, one above the other, and a reversing mechanism in which the first and second printers are arranged at one end of the housing. Is developing a double-sided printing device with a configuration that folds the continuous paper transport path.

However, a common problem when two-sided printing is performed on continuous paper by two printers is that when continuous paper is transported, it is shifted to one side in the paper width direction (paper transport reference end). When the paper is to be fed, the first printer and the second printer may have the paper transport reference ends to be determined at one end in the width direction of the paper, which are opposite to each other. For example, the left end (left end of the front surface) of the sheet as viewed from the first printer side is set as a sheet transport reference end,
Assuming that the left end (left end of the back surface) of the sheet as viewed from the second printer side is the sheet conveyance reference end, the left end of the back surface is located at the right end of the front surface, and these are the sheets as viewed from the same side of the sheet. Are located on opposite sides in the left-right width direction. As a result, there were the following problems to be solved.

FIG. 2A is a plan view of two upper and lower ink jet printers 2A and 2B included in the double-sided printing apparatus 1 according to the embodiment of the present invention. Yes, the lower side is shown as the first printer 2A, and the upper side is shown as the second printer 2B. Reference numeral 110 denotes roll paper in which continuous paper is wound in a roll shape. The roll paper is sent to the lower first printer 2A in the direction of arrow A, and after being inverted by the reversing mechanism, is sent to the upper second printer 2B. On the other hand, it is sent in the direction of arrow B. In the case of this double-sided printing apparatus 1, the paper transport reference end when transporting the roll paper 110 is the roll paper 1
10, the left end of the lower first printer 2A when viewed from the front side, and the upper second printer 2
In B, the right end 110B (left end when viewed from the back surface) when viewed from the same surface (front surface) is the transport reference end. For this reason, the first printer 2A and the second printer 2B
The positions of the digit and the 80th digit are reversed.

Here, reference numeral 61 denotes a paper detector provided at the entrance of the first printer 2A for detecting passage of the leading and trailing ends, and reference numeral 62 denotes a paper detector provided at the entrance of the second printer 2B. When viewed in the width direction of the sheet, each of them is provided at a distance d, for example, about 10 mm inside from the transport reference end side. In short, the paper detectors 61 and 62 detect different portions of the same paper in the width direction.

For this reason, if the leading edge of the sheet is obliquely cut as shown in FIG. 2B due to some cause, for example, a sheet jam has occurred and the sheet is reset, the first printer 2A The paper detector 61 detects the hypotenuse base Y1, and the paper detector 62 of the second printer 2B detects the hypotenuse base Y2. Here, assuming that printing is performed at the same position on the front surface and the back surface of the sheet, assuming that the allowable range regarding the perpendicularity that can be allowed is δY, the two detection positions Y1 and Y2 are too far apart in the sheet conveyance direction, and the allowable range δY is Do not overlap,
The printing position is shifted between the front side and the back side of the paper.

Therefore, an object of the present invention is to ensure the orthogonality of the front end of the roll paper, and in the case of a double-sided printing apparatus, as described above, the print position in the paper transport direction is set between the front and back surfaces of the paper. When a shift occurs, the leading edge of the continuous paper is cut in a range having a right angle as shown by a cut line 63 in FIG. 2B, thereby detecting the leading edge detection position of the first printer 2A and the second printer 2B. By making the same, it is an object of the present invention to prevent the printing position in the paper transport direction from being shifted with respect to the printing performed on the front surface and the back surface of the paper.

[0011]

According to a first aspect of the present invention, there is provided a printing apparatus that prints on roll paper by a printing unit and cuts each print unit by a cutter. The paper detector and the paper leading edge detector are arranged before and after in the paper transport direction and separated in the paper width direction, and the roll paper is detected by the paper detector and then detected by the paper leading edge detector By detecting the time skew or distance difference before being compared with a known value to detect the bending of the orthogonality of the front end of the paper,
When the bending exceeds an allowable range, a control means for cutting and correcting the leading end portion of the roll paper with the cutter is provided.

This includes both a form in which printing is performed on both sides of a sheet by two printers and a form in which single-sided printing is performed by one printer. Is skewed more than the allowable limit, that portion can be cut to ensure the orthogonality of the front end of the roll paper.

The "distance difference" here is a broad concept including a difference in the number of steps between an encoder and a step motor.

According to a second aspect of the present invention, there is provided a printing apparatus according to the first aspect, wherein the printer includes two upper and lower printers in a housing, and the first printer performs printing on one side of roll paper; After the roll paper is reversed by the reversing mechanism, the second
A double-sided printing device for printing on the other side of roll paper by a printer, wherein a first printer and a second printer each include the above-described paper detector and a paper leading edge detector, and the first printer includes the above-described roll paper. And a control means for cutting and correcting the tip portion with the cutter.

[0015] Under such a configuration, the printing start positions of both sides can be correctly and accurately adjusted. In other words, due to some cause, for example, a paper jam has occurred and the paper has been set again, the leading end of the roll paper 110 is obliquely cut off as shown in FIG.
Even if the paper detector 61 of A detects the hypotenuse base Y1 and the paper detector 62 of the second printer 2B detects the hypotenuse base Y2, the paper is cut by the cut line 63. Printing can be performed at the same position.

According to a third aspect of the present invention, there is provided a printing apparatus which prints on roll paper by a printing unit and cuts the print unit by a cutter. And a paper leading edge detector is disposed between the exit side of the printing unit and the cutter downstream thereof, and the paper detector is located within the width of the roll paper and at one side in the width direction of the roll reference position. Side, and the paper leading edge detector is arranged within the width of the roll paper and on the other side in the width direction, and as a means for controlling the cutter, the paper leading edge is detected after the roll paper is detected by the paper detector. The number of steps up to detection by the detector is counted, and the number y of steps is a value obtained by adding an allowable value n to the number N of steps of the transport distance from the paper detector to the paper leading edge detector which is known in advance. If the allowable value n is lower than the lower limit, "normal" When the allowable value n is larger than the lower limit and equal to or smaller than the upper limit, the cutter is operated in the "correction" mode to cut the front end of the roll paper to secure the orthogonality, and then perform the transport operation. To do
When the allowable value n exceeds the upper limit, a control unit is provided for pulling the roll paper back so that the user can cut the front end side of the roll paper in the “abnormal” mode.

According to the present invention, the three modes of "normal", "correction", and "abnormal" are clearly distinguished, and the bending of the orthogonality is automatically corrected when the adjustment is a slight deviation. Since the printer enters the mode, the user can use the printing apparatus without being aware of such a bend, and as a result, it is possible to obtain a print in which the front and back printing positions are aligned.

According to a fourth aspect of the present invention, there is provided a printing apparatus according to the third aspect, wherein the printer includes two printers in an upper and lower part in a housing, and the first printer performs printing on one side of roll paper. After the roll paper is reversed by the reversing mechanism, the second
A double-sided printing apparatus for printing on the other side of roll paper by a printer, wherein the arrangement of printing digits of the first printer and the second printer is arranged in reverse with respect to the width direction of the roll paper. I do.

By arranging the upper and lower printers relative to each other as described above, the printers can have the same configuration in common.
The manufacturing cost can be reduced by using the upper and lower printers in common.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a schematic side sectional view showing an embodiment of a double-sided printing apparatus according to the present invention, and FIG. 4 is a schematic enlarged side sectional view of a first inkjet printer constituting a part of the double-sided printing apparatus. FIG. 5 is a sectional view showing the configuration of the cutter portion.

In FIG. 3, the duplex printing apparatus 1 has two ink jet printers 2A and 2B arranged vertically in a housing thereof, the lower side being a first printer 2A and the upper side being a second printer 2A. The printer 2B is provided. The two-sided printing apparatus 1 is mounted on a mount 6 with casters 4, and the mount 6 is also mounted with an ink cartridge 6A for supplying ink to two inkjet printers 2A and 2B.

<First Printer 2A> First printer 2A located on the lower side
The inkjet printer 2A includes a printing unit 3 and a paper feeding unit 5 provided upstream of the printing unit 3 in the paper transport direction.
And a paper discharge unit 7 formed downstream of the printing unit 3.

An auto-loading roller 8 is provided on the upstream side of the paper feeding section 5, and an auto-loading detector 9 is provided adjacent to the auto-loading roller 8. A roll paper holder 10 is arranged on the upstream side of the auto-loading roller 8, and the roll paper 11 is set therein in a rotatable state. When the roll paper 11 passes between the auto-loading rollers 8, it receives an appropriate amount of feeding action from the roll paper roll.

The fed roll paper 11 reaches a paper feed roller 19 (FIG. 4) composed of a lower paper feed drive roller 15 and an upper paper feed driven roller 17, where it is precisely fed in the printing process. While receiving the operation, the paper is fed along a horizontal transport path to the print head 21 located on the downstream side of the paper feed roller 19.

A paper detector 61 composed of a micro switch is provided at the paper supply unit 5, that is, at the entrance of the first ink jet printer 2A. The paper detector 61 is provided at a distance d, for example, about 10 mm inward from the left end side, which is the transport reference end, as viewed in the width direction of the paper.

In the present embodiment, the print head 21 is located above the transport path of the roll paper 11. The print head 21 is supported by a carriage 23, and the carriage 23 can reciprocate in a direction perpendicular to the sheet feeding direction. A platen 25 is provided at a position facing the print head 21. The platen 25 supports the roll paper 11 from below when printing on the roll paper 11 by the print head 21. The distance between the print head 21 and the platen 25 can be appropriately adjusted according to the thickness of the roll paper 11, so that the roll paper 11 can smoothly print on the platen 25 and perform high quality printing. It has become. The roll paper 11 printed by the print head 21 is discharged by a discharge roller 27 provided in the discharge unit 7.

The paper discharge roller 27 is composed of a lower paper discharge drive roller 29 and an upper paper discharge driven toothed roller 31, and the roll paper 11 is pulled out and discharged by the rotation of the paper discharge drive roller 29. Mechanism. Further, downstream of the paper discharge roller 27, a paper leading edge detector 6 is provided.
4 are provided. Although described later, the paper leading edge detector 64 is provided so as to detect a paper edge side opposite to the paper detector 61 as shown in FIG.

Further, on the downstream side of the sheet leading edge detector 64, a first transport driving roller 33 as a feeding roller is provided.
And applies a driving force to the roll paper for transporting the roll paper 11 discharged by the paper discharge roller 27 toward the second inkjet printer 2B located on the upper side.

<Cutter 35> A cutter 35 for cutting the roll paper 11 is provided immediately before the first transport driving roller 33. The cutter 35 applies the roll paper 11 to the surface opposite to the surface printed on the roll paper 11 by the first inkjet printer 2A before the print head 21 of the second inkjet printer 2B starts printing.
And cuts the portion printed by the first inkjet printer 2A into a cut sheet state.

In the case of the present embodiment, the cutter 35 comprises a fixed blade 71 and a rotary blade 72 as shown in FIG. 5, and the rotary blade 72 is eccentrically mounted on a cutter holder 73.
The cutter holder 73 can be moved by the timing belt 74 in the same direction of the carriage 23.

At the time of cutting, the roller 75 located immediately upstream of the cutter 35 is lifted to the position indicated by the broken line and presses the roll paper 110. The upper side of the first transport drive roller 33 on the exit side is lifted by paper. Further, the guide member 76 is rotated to the obliquely downward position shown by the broken line to secure a falling path of the cut waste.

<Second Printer 2B> The second printer located on the upper side
The ink jet printer 2B has basically the same configuration as the first ink jet printer 2A located on the lower side. Therefore, members having the same functions are denoted by the same reference numerals as those used for the first ink jet printer 2A. . The paper detector 62 is connected to the first inkjet printer 2.
A has the same configuration as the paper detector 61 in FIG. The paper leading edge detector 64 is also provided with a first transport drive roller 39 downstream of the paper discharge roller 27 and as a feed roller, similarly to the case of the first inkjet printer 2A.
It is provided on the upstream side.

The print head 21 of the second ink jet printer 2B is positioned on the paper transport path so as to face the lower surface of the unwound roll paper 11 (the upper surface is inverted when printing by the second ink jet printer 2B). It is located on the upper side (similar to the first inkjet printer 2A).

However, in the case of the double-sided printing apparatus 1, the upper second ink jet printer 2B also has the left end in the paper width direction facing the paper surface on which the roll paper 110 is to be printed, like the lower first ink jet printer 2A. , Is defined as a paper transport reference end when the roll paper 110 is transported. For this reason, generally, as shown in FIG.
The upper second inkjet printer 2B is arranged to be shifted in the paper width direction with respect to the lower first inkjet printer 2A. However, in the present embodiment, C
It is configured as a dedicated machine that performs double-sided printing of the DR jacket and the inner. In such a case, the upper second
The ink jet printer 2B is disposed so as to overlap the lower first ink jet printer 2A. In any case, the lower first ink jet printer 2A has the left end 110A as viewed from the front (front) surface, and the upper second ink jet printer 2B has the same left (110) surface as viewed from the same surface (front surface). Thus, the right end 110B (the left end when viewed from the back) is the transport reference end. Therefore, in the first inkjet printer 2A and the second inkjet printer 2B, the positions of the first digit and the 80th digit of the printing position are reversed.

The second ink jet printer 2B has a first
It is located directly above the inkjet printer 2A,
The paper feed unit 5 of the second inkjet printer 2B is located on the same side as the paper discharge unit 7 of the first inkjet printer 2A.

On the second ink jet printer 2B side,
An auto-loading roller 50 corresponding to the auto-loading roller 8 is provided, and a paper start guide 37 is formed downstream of the auto-loading roller 50. A delivery roll 39 is provided downstream of the paper discharge roller 27 of the second inkjet printer 2B, and a cutter 41 is provided immediately before the delivery roll 39.

Between the discharge section 7 of the first ink jet printer 2A and the paper supply section 5 of the second ink jet printer 2B, the roll paper 11 printed by the first ink jet printer 2A is applied to both left and right ends of the roll paper 11. Are formed in the same ink jet printer 2B in a state where they are located in the same plane. The transport drive roller 33 described above is disposed in the middle of the guide path 43, and the paper end guide 37 forms a part of the guide path 43.

As shown in FIG. 3, a reversing path (reversing mechanism) 45 having a vertically U-shaped cross section is formed in the middle of the guide path 43. The inversion path 45
Is curved only in one direction so that the right and left ends of the roll paper 11 pass through the same plane, respectively, and has an inlet 47 formed on the first inkjet printer 2A side and an outlet 47 formed on the second inkjet printer 2B side. 49 are formed. Roll paper 11 that has passed first transport drive roller 33
Enters the entrance 47 of the reversing path 45 horizontally, proceeds upward while deforming into a U-shape in the reversing path 45, and then horizontally exits from the exit 49 of the reversing path 45 to the paper end guide 37. It has become.

In the middle of the reversing path 45, the above-mentioned auto-loading roller 50 is provided as a second transport driving roll for applying a transport driving force to the cut paper cut by the cutter 35. An auto loading detector is provided immediately after the auto loading roller 50. In the middle of the reversing path 45, two paper overlap detectors 51 are provided. The detector 51 detects the overlap between the cut paper cut by the cutter 35 and the roll paper 11 and makes it necessary. The transport speed of the cut sheet or roll paper 11 is adjusted accordingly.

<Operation> The operation of the above configuration will be described. The roll paper 11 is fed out from the roll paper holder 10, and the auto loading roller detector 9, the paper detector 61
Are sequentially detected.

When the paper feed roller 19 of the first inkjet printer 2A is driven, the roll paper 11 passes below the print head 21 in a horizontal state, and printing is performed on the upper surface of the roll paper 11. First inkjet printer 2
In A, printing is performed on one side (front side) of the sheet, exits the sheet ejection drive roller 29 of the sheet ejection section 7, further passes through the sheet edge detector 64, and the first transport drive roller 3 serving as a delivery roller.
It is carried out from 3.

The printing portion is the first transport drive roller 33
Enters the reversing path 45 from above, progresses upward along the path in a U-shape, and the paper surface is reversed. At this time, since both ends of the roll paper 11 move within the same plane, there is no right and left deviation, and no movement such as twisting or bending easily giving a habit to the paper. After the printing by the first inkjet printer 2A is completed, when the end of the print portion passes the position of the cutter 35, the cutter 35 acts on the roll paper 11 to cut the print portion from the roll paper 11.

The cut print portion becomes a cut sheet state,
When the leading end side receives the driving force by the second transport driving roller 50, it reaches the paper feed roller 19 of the second inkjet printer 2 </ b> B via the paper end guide 37. At this time, the paper is detected by the paper detector 62 provided in the paper supply unit 5 which is the entrance of the second inkjet printer 2B.
In the second ink jet printer 2B, similarly to the first ink jet printer 2A, printing is performed on the inverted upper surface of the cut sheet (the surface not printed by the first ink jet printer 2A), and the discharge drive roller 29, the sheet is sent out by the feed roller 39 via the sheet leading edge detector 64.

The cutter 41 appropriately cuts the front end and the rear end of the printed portion in the cut sheet state so that the cut sheet has a predetermined length. For example, when the front end portion of the cut sheet is already cut at an accurate position by the cutter 35, the cutter 41 cuts only the rear end of the cut sheet with the correct length. Can be used for Further, the cutter 41 may be operated to eliminate the upper and lower margins of the cut sheet.

<Control> Next, when the orthogonality of the front end portion of the sheet is curved and the sheet is skewed, the cutter 35 is operated to cut the front end portion at a right angle, and printing is performed by two upper and lower printers. Control for accurately positioning the region will be described. The control means for performing this control is constituted by a control device mainly composed of a built-in microcomputer.

As described above, the paper detector 61 is provided at the entrance of the first inkjet printer 2A, and the paper detector 62 is provided at the entrance of the second inkjet printer 2B, and is shown in FIG. 2 (a). As described above, each sheet is provided at a position inside, for example, about 10 mm inside by a distance d from the conveyance reference end side when viewed in the width direction of the sheet. That is, the paper detector 61 moves toward the left end of the paper and the paper detector 6
No. 2 detects the right end of the same sheet in the width direction.

In FIG. 2A, the roll paper 110 is
Arrow A for the lower first inkjet printer 2A
After being sent to the second ink jet printer 2B on the upper side, the sheet is sent in the direction of arrow B to the upper second inkjet printer 2B.

FIG. 1 is a plan view showing a state where the front end of the roll paper 110 is approaching the lower first ink jet printer 2A. As shown in the figure, a paper detector 61 is located at the entrance first, and a paper leading edge detector 64 is located downstream of the paper detector, more precisely, between the paper discharge roller 27 and the cutter 35. Here, the distance between the paper detector 61 and the paper leading edge detector 64 is known based on the number of pulses by an encoder provided on the rotation shaft of the drive motor, and the number N of paper feeding steps is known. .

Therefore, considering a margin length which is considered to maintain the perpendicularity of the front end of the roll paper 110 in practice, this is added as the margin step number n, and N ± n is set as an appropriate range.

As described above, the paper detector 61 is provided so as to detect the inside of the sheet from the one end in the width direction by a distance d (about 10 mm).
As shown in FIG. 1, it is also provided so as to detect inside by a distance d from the other end in the width direction of the sheet.

Now, it is assumed that the front end of the roll paper 110 is in a diagonal cut-out state in which the right end in the width direction protrudes as shown by a virtual line 66 in FIG. In this case, the left side of the front end of the paper is first detected by the paper detector 61 first. Thereafter, the roll paper 110 is sent in the Y direction. Since the front end of the sheet has a skew shape protruding more toward the right end, the right end side of the sheet is detected first by the sheet front end detector 64 on the downstream side. That is, after the left side of the front end of the paper is detected by the paper detector 61, the number of steps y is smaller than the normal number of times before the roll paper 110 is fed in the Y direction and the front end of the paper is detected by the paper front end detector 64. Is measured.

On the other hand, assuming that the front end of the roll paper 110 is obliquely cut off, as shown by the phantom line 67 in FIG. After the detection at 61, a larger number of steps y are measured than in the normal state before the roll paper 110 is fed in the Y direction and the front end of the paper is detected by the paper front end detector 64.

Therefore, the number of steps y from the time when the paper detector 61 is turned on to the time when the paper leading edge detector 64 is turned on is counted (measured). It is determined that it is within the allowable range.

N−n <y <N + n, y: number of paper feed steps Actually, the value of the allowable value n is the number of steps corresponding to about ± 2 mm.

In the present embodiment, (1) the range of the allowable value n of 2 mm or less (n ≦ 2 mm) in the dimension conversion (n ≦ 2 mm) is set to the “normal” mode, and (2) the allowable value n is 2 to 10 mm (2 m).
The range of m <n ≦ 10 mm) is classified into three modes as a “correction” mode in which the front end of the sheet is cut, and (3) a case of 10 mm <n as an “abnormal” mode.

First, in the case of the first “normal” mode, that is, when n ≦ 2 mm, the roll paper 10 is fed as it is without cutting the front end of the roll paper 10, and the position of the paper detector 61 is stepped. On the basis of the position (calculation reference position) of the sheet leading end detector 64 calculated by adding the number N, the leading end of the sheet is at the position of the predetermined count value advanced by an amount corresponding to the transport distance L of the printing unit, and the trailing end side. To cut.

Next, in the case of the second "correction" mode, that is, when the allowable value n is within the range of 2 to 10 mm (2 mm <n.ltoreq.10 mm) and the front end of the paper is to be cut, With reference to the calculation reference position of the leading edge detector 64 as a reference, cutting is performed at a position of a count value advanced by an amount corresponding to a predetermined maximum value of n (here, 10 mm) from the time when the paper front end is detected by the paper detector 61. . FIG. 1 shows the positional relationship between the line 68 to be cut and the cutter 35 by virtual lines.

However, the cut position is not determined uniformly regardless of the degree of the orthogonality bending as described above.
The control means may calculate an appropriate cut position corresponding to the degree of orthogonality bending, and cut there.

Further, in the case of the third "abnormal" mode, that is, when the allowable value n exceeds 2 to 10 mm, the paper feed roller 19 is reversed to pull back the roll paper 10, and the leading end side of the roll paper 10 is moved. Let the user re-cut and then
It is transported to the inkjet printer 2A. A possible cause of such an abnormal mode is, for example, a case where roll paper is set again due to a jam.

As described above, in a state where the two sensors including the paper detector 61 and the paper leading edge detector 64 are simultaneously turned on, the time difference or the number of transport steps since the paper detector 61 was turned on was measured. From the result, the paper leading edge detector 6
4 and whether the front end side of the paper is inclined or not, and if necessary, cuts the front end side to ensure orthogonality, so that the paper detection position in the second inkjet printer 2B exists at the right end. However, the paper can be stopped at the same transport position detected at the leftmost paper detection position of the first inkjet printer 2A, and printing can be performed at the same position on the front and back of the paper.

In the above-described embodiment, a case has been described in which printing is performed on the front and back of a sheet by two printers. However, the present invention is not limited to this. When the inclination is skew exceeding the allowable limit, it can be applied as a technique for cutting the portion to secure the orthogonality of the front end.

In the above embodiment, the case of an ink jet printer has been described. However, the present invention can be applied to other dry or wet printers.

[0063]

As described above, according to the present invention, in a state where the two sensors including the paper detector and the paper leading edge detector are simultaneously turned on, the time difference between when the paper detector is turned on,
Or, from the magnitude of the result of measuring the number of transport steps, it is determined whether the paper leading edge detector and the front end side of the paper are inclined, and if necessary, the front end side is cut to ensure orthogonality. Therefore, when the front end of the sheet is skewed more than the allowable limit, the portion can be cut to ensure the orthogonality of the front end of the roll paper. This includes both a form in which printing is performed on both sides of a sheet by two printers and a form in which one printer performs single-sided printing.

In a configuration in which two printers are arranged vertically, even if the paper detection position of the second printer exists at the right end, it is detected at the left end paper detection position of the first printer. It is possible to correctly detect the front end of the roll paper at the same transport position as above and print at the same position on the front and back of the paper.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the operation of a duplex printing apparatus according to the present invention.

FIG. 2 is a diagram for explaining the operation of the duplex printing apparatus of the present invention.

FIG. 3 is a schematic side sectional view showing an embodiment of a double-sided printing apparatus according to the present invention.

FIG. 4 is a schematic enlarged side sectional view of a first ink jet printer constituting a part of the duplex printing apparatus according to the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a cutter portion of the duplex printing apparatus according to the present invention.

FIG. 6 is a diagram showing a reversing mechanism of a conventional duplex printing apparatus.

[Explanation of symbols]

 2A 1st inkjet printer (1st printer) 2B 2nd inkjet printer (2nd printer) 3 printing part 7 paper discharge part 11 roll paper 19 paper feed roller 21 print head 25 platen 27 paper discharge roller 33 first conveyance drive roller 35 Cutter 39 Feeding roller 41 Cutter 50 Second transport drive roller 61 Paper detector 62 Paper detector 63 Cut line 64 Paper leading edge detector 66 Virtual line indicating front end of roll paper 67 Virtual line 68 indicating front end of roll paper Should be cut Line (virtual line) 110 Roll paper

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B26D 5/34 B26D 5/34 A B41J 15/04 B41J 15/04 B65H 7/06 B65H 7/06 23/32 23 / 32 35/08 35/08 F term (reference) 2C058 AB16 AC07 AE04 AE09 AF06 AF51 LA03 LB10 LB17 LB35 LC11 LC15 2C060 BA01 BC03 BC04 BC12 BC15 BC84 BC95 BC96 3C024 CC01 DD01 FF01 3F048 AA05 AB01 AC04 BA11 BB04 DC03 CC04 DB03 DC07 AA02 GA11 GA15

Claims (4)

[Claims] 1. A printing device that prints on a roll paper by a printing unit and cuts by a cutter for each print unit, wherein the paper detector and the paper are separated from each other in a paper transport direction and in a paper width direction. By arranging a leading edge detector and comparing the time difference or distance difference from when the roll paper is detected by the paper detector to when the roll paper is detected by the paper leading edge detector to a known value, the bending of the orthogonality of the leading edge of the paper is determined. A printing apparatus, comprising: a control unit for detecting and, when the bending exceeds an allowable range, cutting and correcting the leading end portion of the roll paper with the cutter. 2. The printing apparatus according to claim 1, further comprising two printers in the housing, one above the other, and the first printer performs printing on one side of the roll paper, and the roll paper is reversed by a reversing mechanism. A two-sided printing apparatus that prints on the other side of the roll paper with a second printer after that, the first printer and the second printer each include the above-described paper detector and the paper leading edge detector, and the first printer is A printing apparatus, comprising: control means for cutting and correcting the leading end portion of the roll paper by the cutter. 3. A printing apparatus for printing on roll paper by a printing unit and cutting it by a cutter for each printing unit, wherein a paper detector is arranged at an entrance side of the printing unit, and an exit side of the printing unit and the paper detector are arranged at the entrance. A paper edge detector is arranged between the cutter and the cutter on the downstream side.The paper edge detector is moved within the width of the roll paper to the conveyance reference position on one side in the width direction, and the paper edge detector is rolled. In the width of the paper, it is arranged on the other side in the width direction, and as means for controlling the cutter, counts the number of steps from when the roll paper is detected by the paper detector to when it is detected by the paper leading edge detector. Then, the number of steps y is compared with a value obtained by adding a permissible value n to the number of steps N of the transport distance from the paper detector to the paper leading edge detector, which is known in advance. Causes the normal transport operation to be performed as the "normal" mode, and the allowable value n When the value is larger than the lower limit and is equal to or smaller than the upper limit, the cutter is operated as the “correction” mode, the front end of the roll paper is cut to ensure the orthogonality, and then the transport operation is performed. A printing apparatus comprising a control unit for pulling back the roll paper so that the user cuts the front end side of the roll paper in the “abnormal” mode. 4. The printing apparatus according to claim 3, further comprising two printers in the housing, one above the other, and the first printer performs printing on one side of the roll paper, and the roll paper is reversed by a reversing mechanism. And a second printer for printing on the other side of the roll paper by a second printer, wherein the arrangement of the printing digits of the first printer and the second printer is:
A printing apparatus characterized in that the printing apparatus is arranged in reverse in the width direction of the roll paper.