JP7351695B2 - Print media reversing device - Google Patents

Description

The present invention relates to a print medium reversing device that transports print media in a switchback manner and transfers the print medium to a downstream device.

Conventionally, a print medium reversing device has been proposed that receives a print medium that has been subjected to printing processing in a printing device, performs switchback conveyance to reverse the print medium, and then discharges the print medium to the downstream side (for example, see Patent Document 1) ).

Such a print medium reversing device includes a switchback path for reversing and conveying the print medium, and a pair of switchback rollers provided on the switchback path. Then, by rotating the switchback roller pair in the forward direction and the opposite direction on the switchback path, the print medium is reversed and conveyed.

Japanese Patent Application Publication No. 5-35018

Here, when the print medium is reversed by the print medium reversing device as described above and delivered to the downstream device, the print media that are sequentially conveyed from the printing device at a predetermined conveyance speed are not collided with each other, and the downstream side Since it is necessary to sequentially discharge the print medium to the printing apparatus, it is necessary to transport the print medium at a transport speed faster than the transport speed of the print medium of the printing device.

Therefore, after the print medium is received in the print medium reversing device, the rotational speed of the pair of switchback rollers is accelerated from the time when the print medium is conveyed to a predetermined acceleration start position to increase the conveyance speed.

The timing of accelerating the rotational speed of the pair of switchback rollers is preferably after the trailing edge of the print medium has passed through a conveyance roller disposed at the most downstream position of the printing device.

However, in recent years, print medium reversing devices have become smaller and the switchback path has become shorter, so it is necessary to accelerate the conveyance speed while the trailing edge of the print medium remains inside the printing device.

If the rotational speed of the pair of switchback rollers is accelerated while the print medium is nipped by the conveyance roller downstream of the printing device, the print medium ejected from the printing device will be pulled by the pair of switchback rollers, causing the transfer roller to Paper dust is generated between the printer and the print media. This paper powder may adhere to the inkjet head of a printing device, for example, and have an undesirable effect. Furthermore, the print medium ejected from the printing device is pulled by the pair of switchback rollers, which may cause failure of the conveyance rollers of the printing device. Particularly, when the conveyance roller is a conveyance roller equipped with a one-way clutch, failure is likely to occur due to its structure.

In order to suppress the above-mentioned generation of paper dust and failure of the conveyance roller, a method can be considered in which the above-mentioned acceleration start position is set as far downstream as possible within the range of the switchback path.

However, when conveying a print medium having a short length in the conveyance direction, if the acceleration start position is set further downstream from the pair of switchback rollers, a sufficient conveyance distance for acceleration for reversal and high-speed conveyance cannot be secured.

In such cases, if the acceleration start position is placed on the downstream side, the acceleration of the conveyance speed of the print medium will be delayed, and sufficient reversal margin time between the print media will not be secured, resulting in misalignment with the preceding print medium. There is a possibility that a problem of collision with the next print medium may occur. Note that the reversal margin time is defined as the time from when the trailing edge of a print medium that is previously conveyed by a pair of switchback rollers passes the position of the pair of switchback rollers until the leading edge of the next print medium reaches the position of the pair of switchback rollers. This is the time it takes to reach the position.

In view of the above circumstances, the present invention provides a printing medium reversing device that can suppress the generation of paper dust and failure of the conveyance roller of a printing device, and can also secure a sufficient reversal margin time between print media. The purpose is to

The print medium reversing device of the present invention includes a switchback path for receiving a print medium conveyed by a pair of conveyance rollers, transporting the received print medium in a switchback manner, and delivering it to the downstream side, and a switchback path provided on the switchback path. , a switchback roller unit that switches back the print medium by reversing the rotational direction, and a control unit that controls the rotation speed of the switchback roller unit, and the control unit adjusts the received print medium to a predetermined acceleration start position. The rotational speed of the switchback roller section is accelerated from the time when the print medium is conveyed, and the acceleration start position is changed in accordance with the length of the print medium in the conveyance direction.

According to the print medium reversing device of the present invention, the rotational speed of the switchback roller section is accelerated from the time when the received print medium is conveyed to a predetermined acceleration start position, and the acceleration start position is Change depending on the situation. If the print medium is long, by setting the acceleration start position to the downstream side, it is possible to shorten the conveyance distance of the print medium when it is nipped by the conveyance roller of the printing device, thereby reducing the generation of paper dust. It is possible to suppress failures of transport rollers of printing apparatuses and printers. Further, when the print medium is short, by setting the acceleration start position on the upstream side, a sufficient reversal margin time between the print media can be secured.

A diagram showing a schematic configuration of a printing system using an embodiment of a print medium reversing device of the present invention A block diagram showing a schematic configuration of the control system of the printing system shown in FIG. A timing chart showing detection timings of an introduction sensor, a reversal sensor, and a switchback sensor, and changes over time in the conveyance speed of an introduction roller pair, a reversal entry roller pair, and a switchback roller pair. A diagram showing an example of a table that associates print medium sizes and acceleration start positions. A diagram showing the conveyance path extending in a straight line from the inkjet head of the printing device to the pair of switchback rollers of the print media reversing device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A printing system using an embodiment of the print medium reversing device of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a printing system 1 of this embodiment. FIG. 2 is a block diagram showing a schematic configuration of a control system of the printing system shown in FIG. 1. As shown in FIG.

As shown in FIG. 1, the printing system 1 of this embodiment includes a printing device 10, a print medium reversing device 20, and a post-processing device 30. Note that since the printing system 1 of this embodiment is characterized by the configuration of the print medium reversing device 20, only a part of the configuration of the printing device 10 and the post-processing device 30 is shown.

The printing device 10 of this embodiment is an inkjet printing device, and performs printing processing by ejecting ink onto a printing medium. The printing device 10 performs a printing process on a print medium using basic color inks such as CMYK and gray. The printing device 10 has, for example, a line head type inkjet head that ejects ink of each color. In FIG. 1, only the most downstream inkjet head 11 among a plurality of inkjet heads that eject ink of each color is shown, and the configuration upstream of the inkjet head 11 is omitted from illustration.

Further, the printing apparatus 10 is provided with a platen roller 12 and two pairs of conveyance rollers 13 and 14 with one-way clutches on the downstream side of the inkjet head 11. The platen roller 12 and the pair of conveyance rollers 13 and 14 nip the print medium that has been subjected to printing processing by the inkjet head 11 or the like and is conveyed on the platen, and convey it toward the print medium reversing device 20 to remove the print medium. This is a roller that delivers the print medium to the reversing device 20.

The printing device 10 includes a conveyance motor 15 that rotationally drives a platen roller 12 and a pair of conveyance rollers 13 and 14 .

In the present embodiment, the printing device 10 is an inkjet printing device, but the printing device 10 is not limited to this, and may be a laser printing device or a stencil printing device having the pair of conveyance rollers 13 and 14 with a one-way clutch described above.

The print medium reversing device 20 receives the printed print medium conveyed by the pair of conveyance rollers 13 and 14 of the printing device 10, and delivers the received print medium to the post-processing device 30. The print medium reversing device 20 includes a discharge paper conveying section 21 and a reversing section 22 .

Here, the route indicated by the thick line in FIG. 1 is the conveyance route along which the print medium is conveyed in the print medium reversing device 20. Among the conveyance paths, the path shown by the solid line is the paper discharge path RD, the path shown by the broken line is the reversal entrance path RI, the path shown by the one-dot chain line is the reversal path RS, and the path shown by the two-dot chain line is the reversal exit path RO. In this embodiment, the reverse entry route RI, the reverse route RS, and the reverse exit route RO correspond to the switchback route of the present invention. A plurality of guide plates are arranged on the reversing entry route RI, the reversing route RS, the reversing exit route RO, and the paper discharge route RD so that print media of various sizes can be conveyed.

The paper discharge conveyance section 21 conveys and discharges the print medium discharged from the printing device 10 without reversing it. As shown in FIGS. 1 and 2, the paper ejection transport section 21 includes a pair of introduction rollers 23, an introduction motor 24, a pair of face-up rollers 25, a paper ejection motor 43, a pair of rising rollers 26, and a rising motor 27. , a pair of discharge rollers 28 , and a discharge motor 29 .

The introduction roller pair 23 takes the print medium discharged from the printing device 10 into the print medium reversing device 20 . The introduction roller pair 23 is arranged at the most upstream side of the paper discharge path RD. The upstream end of the paper discharge path RD is connected to the downstream end of the conveyance path of the printing device 10.

The introduction motor 24 rotates the introduction roller pair 23 . The paper discharge motor 43 rotates the face-up roller pair 25.

The face-up roller pair 25 transports the print medium taken in from the printing device 10 by the introduction roller pair 23 toward the rising roller pair 26 . The face-up roller pair 25 is arranged downstream of the introduction roller pair 23 along the paper discharge path RD.

The pair of rising rollers 26 conveys the print medium conveyed from the pair of face-up rollers 25 or the pair of intermediate rollers 36 (described later) toward the pair of discharge rollers 28 . The pair of rising rollers 26 is arranged on the paper discharge route RD near the downstream side of the confluence of the paper discharge route RD and the reverse exit route RO.

The lift motor 27 rotates the pair of lift rollers 26 .

The discharge roller pair 28 conveys the print medium conveyed from the rising roller pair 26 and discharges it to the post-processing device 30 . The discharge roller pair 28 is arranged at the most downstream portion of the paper discharge path RD.

The discharge motor 29 rotates the discharge roller pair 28 .

The reversing unit 22 performs switchback conveyance for vertically reversing the print medium discharged from the printing apparatus 10 . As shown in FIGS. 1 and 2, the reversing unit 22 includes a path switching flipper 31, a path switching solenoid 32, a pair of reversing entry rollers 33, a reversing entry motor 44, a pair of switchback rollers 34, and a switchback motor. 35, an intermediate roller pair 36, an intermediate conveyance motor 37, an introduction sensor 38, a reversal sensor 39, and a switchback sensor 40.

The path switching flipper 31 switches the conveyance path of the print medium between the paper discharge path RD and the reverse entry path RI. The route switching flipper 31 is arranged at a branch point between the paper discharge route RD and the reverse entry route RI.

The route switching solenoid 32 drives the route switching flipper 31.

The reverse entry roller pair 33 transports the print medium guided to the reverse entrance path RI by the path switching flipper 31 toward the switchback roller pair 34 . The reverse entry roller pair 33 is disposed on the reverse entrance route RI, between the route switching flipper 31 and the switchback roller pair 34.

The switchback roller pair 34 switches back and conveys the print medium that has entered the reversal path RS from the reversal entry path RI and sends it out to the reversal exit path RO. The switchback roller pair 34 is configured to be rotatable in the forward direction and the reverse direction in order to perform switchback conveyance of the print medium. The switchback roller pair 34 is arranged on the reversal route RS near the confluence of the reversal entry route RI, the reversal route RS, and the reversal exit route RO. The switchback roller pair 34 is an example of the configuration of the switchback section of the present invention. The switchback section is not limited to this, and may include a pair of belt conveyance sections that are arranged opposite to each other and can be driven in reverse.

The switchback motor 35 rotates the switchback roller pair 34 in the forward direction or in the opposite direction.

The intermediate roller pair 36 conveys the print medium switched back by the switchback roller pair 34 toward the rising roller pair 26 . The intermediate roller pair 36 is located on the reversing exit path RO and between the switchback roller pair 34 and the rising roller pair 26.

The reversal entry motor 44 rotationally drives the reversal entry roller pair 33 , and the intermediate conveyance motor 37 rotationally drives the intermediate roller pair 36 .

The introduction sensor 38, the reversal sensor 39, and the switchback sensor 40 are sensors that detect the leading edge of the print medium being conveyed. The introduction sensor 38, the reversal sensor 39, and the switchback sensor 40 are composed of, for example, optical sensors.

The introduction sensor 38 is provided on the paper discharge path RD, and is arranged near the downstream side of the introduction roller pair 23. Further, the reversal sensor 39 is provided on the reversal entry path RI, and is arranged near the downstream side of the pair of reversal entry rollers 33. Further, the switchback sensor 40 is provided on the reversal route RS, and is arranged near the downstream side of the switchback roller pair 34.

The post-processing device 30 is arranged downstream of the print medium reversing device 20, and the downstream end of the paper discharge path RD of the print medium reversing device 20 is connected to the upstream end of the conveyance path of the post-processing device 30. A receiving roller 41 is disposed at the most upstream side of the conveyance path of the post-processing device 30 . Further, the post-processing device 30 includes a receiving roller drive motor 42 that rotationally drives a receiving roller 41 . In addition, in FIG. 1, only the receiving roller 41 of the post-processing device 30 is shown, and the configuration downstream of the receiving roller 41 is not shown.

The post-processing device 30 receives the print medium discharged from the print medium reversing device 20 using a receiving roller 41, and performs post-processing on the received print medium. Post-processing includes stapling, punching, sorting, booklet binding, and enclosing. Further, instead of the post-processing device 30, a paper discharge device such as a large capacity paper discharge device may be connected.

The control unit 50 controls the operation of the printing system 1 as a whole. The control unit 50 includes a CPU (Central Processing Unit), a semiconductor memory, a hard disk, and the like. A print medium conveyance control program is installed in the semiconductor memory or hard disk, and the conveyance control program is executed by the CPU to control the print medium conveyance in the printing system 1.

In particular, the control unit 50 of this embodiment controls the rotational speed of the switchback roller pair 34.

Here, in the printing system 1 of the present embodiment, when the print medium is reversed by the print medium reversing device 20 and discharged to the post-processing device 30, the print medium is sequentially conveyed from the printing device 10 at a predetermined conveyance speed. Since it is necessary to sequentially discharge the print media to the post-processing device 30 without causing them to collide, it is necessary to transport the print media at a transport speed faster than the transport speed of the print media of the printing device 10.

Therefore, the control unit 50 controls the rotational speed of the introduction roller pair 23, the reversal entry roller pair 33, and the switchback roller pair 34 from the time when the print medium received by the print medium reversing device 20 is conveyed to a predetermined acceleration start position. and increase the conveyance speed.

The timing of accelerating the rotational speeds of the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34 is preferably after the trailing edge of the print medium passes through the conveyance roller pair 14 of the printing device 10. However, as described above, the print medium reversing device 20 is becoming smaller and the switchback path is becoming shorter, so the conveyance speed is accelerated while the trailing edge of the print medium remains inside the printing device 10. may be required. When the rotational speeds of the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34 are accelerated while the printing medium is nipped between the pair of transport rollers 13 and 14 equipped with a one-way clutch of the printing device 10, the above-mentioned This poses a problem in that it may cause failure of the pair of transport rollers 13 and 14, and paper dust is likely to be generated.

Therefore, in order to suppress the failure of the transport roller pair 13, 14 and the generation of paper powder as much as possible, the control unit 50 of the present embodiment controls the rotational speed of the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34. The above-mentioned acceleration start position at which acceleration starts is changed depending on the length of the print medium in the transport direction.

Specifically, if the length of the print medium in the transport direction is longer than a predetermined threshold, the control unit 50 causes the leading edge of the print medium to reach an acceleration start position near the downstream side of the switchback roller pair 34. From this point on, the rotational speeds of the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34 are accelerated. As a result, after the rotational speeds of the introduction roller pair 23, the reversing entry roller pair 33, and the switchback roller pair 34 start accelerating, the distance that the print medium is conveyed while being nipped by the conveyance roller pair 13, 14 can be shortened. Therefore, it is possible to suppress the failure of the pair of transport rollers 13 and 14 and the generation of paper dust.

On the other hand, if the length of the print medium in the conveyance direction is shorter than a predetermined threshold, the acceleration for reversal by the introduction roller pair 23, the reversal entry roller pair 33, and the switchback roller pair 34 and the conveyance distance for high-speed conveyance are sufficient. Therefore, in such a case, if the introduction roller pair 23, reverse entry roller pair 33, and switchback roller pair 34 start accelerating at the above-mentioned acceleration start position, the acceleration of the conveyance speed of the printing medium will be delayed. As a result, a sufficient reversal margin time between print media cannot be secured, and a problem may occur in which the preceding print medium and the next print medium collide.

Therefore, when the length of the print medium in the conveyance direction is shorter than a predetermined threshold, the control unit 50 of the present embodiment causes the leading edge of the print medium to reach an acceleration start position near the upstream side of the switchback roller pair 34. From this point on, the rotational speeds of the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34 are accelerated. As a result, a sufficient reversal margin time can be ensured, and collisions of printing media can be avoided. Note that the acceleration start position will be detailed later.

Next, the operation of the printing system 1 will be explained. Note that since the printing system 1 of this embodiment is characterized by the operation of the print medium reversing device 20, the operation of the print medium reversing device 20 will be mainly described.

The conveyance operation of the print medium reversing device 20 is performed in accordance with the printing operation of the printing device 10. The control unit 50 receives an instruction from the printing device 10 as to whether to eject the print medium with its front and back sides as they are, or to invert the print medium and eject it.

When the print medium is reversed and discharged, the control unit 50 starts driving the introduction motor 24, the lift motor 27, the discharge motor 29, the switchback motor 35, the intermediate conveyance motor 37, and the reverse entry motor 44. As a result, the driving of the introduction roller pair 23, the rising roller pair 26, the ejection roller pair 28, the switchback roller pair 34, the intermediate roller pair 36, and the reversing entry roller pair 33 is started.

Further, the control unit 50 uses the path switching solenoid 32 to set the path switching flipper 31 in the direction of guiding the print medium to the reverse approach path RI.

FIG. 3 shows the detection timing of the print medium of the introduction sensor 38, the reversal sensor 39, and the switchback sensor 40, and the introduction roller pair 23, the reversal entry roller pair 33, and the switchback roller when the print medium is reversed and discharged. 12 is a timing chart showing changes over time in the conveyance speed of the pair 34.

First, the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34 start rotating, and convey the print medium at the same conveyance speed V1 as the print medium conveyance speed of the printing device 10.

Then, when the print medium enters the discharge path RD from the printing device 10, the print medium is guided by the path switching flipper 31 to the reversing path RI while being conveyed by the introduction roller pair 23. At this time, detection of the print medium by the introduction sensor 38 is started at time t1.

Thereafter, the print medium is conveyed by the pair of introduction rollers 23 and the pair of reversal entry rollers 33, and the leading edge of the print medium is detected by the reversal sensor 39.

Then, the control unit 50 measures the elapsed time (conveyance distance of the print medium) T from the time t2 when the leading edge of the printing medium was detected by the reversal sensor 39, and moves the leading edge of the printing medium to a preset acceleration start position 1. At time t3, when t3 is reached, acceleration of the rotational speeds of the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34 is started, and the conveyance speed of the print medium is increased to V2.

Here, the control unit 50 of this embodiment changes the acceleration start position of the conveyance speed of the print medium according to the length of the print medium in the conveyance direction, as described above. The control unit 50 is preset with a table as shown in FIG. 4 in which the size of the print medium and the acceleration start position are associated with each other. The control unit 50 obtains the size of the print medium and determines the acceleration start position by referring to the table shown in FIG. 4 . Note that the size of the print medium may be acquired from the print job, or may be set and input by the user on the operation panel (not shown).

Specifically, in this embodiment, two acceleration start positions 1 and 2 are set. When the size of the print medium (length in the conveyance direction) is equal to or smaller than B4 length (364 mm), the control unit 50 controls the introduction roller pair 23, Acceleration of the rotational speeds of the reverse entry roller pair 33 and the switchback roller pair 34 is started.

On the other hand, if the size of the print medium (length in the transport direction) is A3 length (420 mm) or more, the control unit 50 controls the introduction roller pair from the time when the leading edge of the print medium reaches the acceleration start position 2. 23, start accelerating the rotational speeds of the reverse entry roller pair 33 and the switchback roller pair 34. Note that although the table shown in FIG. 4 only shows the sizes of some print media, acceleration start position 1 or acceleration start position 2 is set for print media of other sizes depending on the length in the transport direction. Ru.

Further, FIG. 4 shows the reversal margin time secured when acceleration start position 1 or acceleration start position 2 is set for each size of print medium. In this embodiment, the print medium size range corresponding to acceleration start position 1 and the print medium size range corresponding to acceleration start position 2 are set so that a reversal margin time of 60 ms or more can be secured. In this way, by changing the acceleration start position so that the reversal margin time is equal to or greater than a preset threshold, it is possible to reliably avoid a collision between the preceding print medium and the next print medium.

Furthermore, FIGS. 5A and 5B are diagrams in which the conveyance path of the printing medium from the inkjet head 11 of the printing device 10 to the pair of switchback rollers 34 of the printing medium reversing device 20 is extended in a straight line. 5A shows a state in which the leading edge of the B4 vertical print medium has reached acceleration start position 1, and FIG. 5B shows a state in which the leading edge of the Ledger vertical print medium has reached acceleration start position 2. There is.

Note that the timing chart in FIG. 3 shows the case where acceleration is started from acceleration start position 1, but when accelerating from acceleration start position 2, acceleration start position 1 shown in FIG. 5A and acceleration start position shown in FIG. 5B are used. From time t3', which is later than time t3, the rotational speeds of the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34 start to be accelerated by a transport time corresponding to the distance between them.

Returning to FIG. 3, the print medium is conveyed at a conveyance speed V2 by the introduction roller pair 23, the reverse entry roller pair 33, and the switchback roller pair 34, and the control unit 50 determines when the trailing edge of the print medium has passed through the introduction sensor 38. From time t5, the rotational speed of the introduction roller pair 23 is decelerated, and the conveyance speed is returned to V1.

Next, the control unit 50 reduces the rotational speed of the reversal entry roller pair 33 from time t6 when the rear end of the print medium passes through the reversal sensor 39, and returns the conveyance speed to V1.

Thereafter, the control unit 50 measures the elapsed time (conveyance distance of the print medium) from time t4 when the leading edge of the print medium was detected by the switchback sensor 40, and switches the switch from time t7 when the preset elapsed time is reached. The rotation of the back roller pair 34 is decelerated and stopped with the rear end of the print medium nipped.

Next, the control unit 50 starts reverse drive of the switchback motor 35 from time t8. This causes the switchback roller pair 34 to start rotating in the opposite direction, and the print medium is conveyed to the intermediate roller pair 36. The conveyance speed by the switchback roller pair 34 and the intermediate roller pair 36 after the start of the reverse rotation drive is set to the reverse speed V3.

The print medium that has been switched back is conveyed by a pair of intermediate rollers 36, a pair of rising rollers 26, and a pair of discharge rollers 28, and is discharged to a post-processing device 30.

On the other hand, when the print medium ejected from the printing device 10 is to be ejected with its front and back sides unchanged, the control unit 50 starts driving the introduction motor 24, the ejection motor 43, the lift motor 27, and the ejection motor 29. As a result, driving of the introduction roller pair 23, the face-up roller pair 25, the rising roller pair 26, and the ejection roller pair 28 is started.

Further, the control unit 50 uses the path switching solenoid 32 to set the path switching flipper 31 in the direction of guiding the print medium from the introduction roller pair 23 to the face-up roller pair 25 .

When the print medium enters the paper discharge path RD from the printing device 10, the print medium is guided by the path switching flipper 31 to the face-up roller pair 25 while being conveyed by the introduction roller pair 23. The print medium is then conveyed by the face-up roller pair 25, the rising roller pair 26, and the ejection roller pair 28, and is ejected toward the post-processing device 30.

In the printing system 1 of the above embodiment, two acceleration start positions 1 and 2 are set as shown in the table shown in FIG. 4, but the present invention is not limited to this. The acceleration start positions may be classified into the above categories and three or more acceleration start positions may be set.

Further, in the printing system 1 of the above embodiment, the acceleration start position is set according to the table shown in FIG. In some cases, the distance from the print medium discharge port of the printing device 10 to the pair of transport rollers 13 and 14 equipped with a one-way clutch may change.

In that case, the distance from the pair of transport rollers 13 and 14 of the printing device 10 to the acceleration start position 1 or the acceleration start position 2 (see FIGS. 5A and 5B) changes, so the size of the print medium corresponding to the acceleration start position 1 changes. It is preferable to change the range and the size range of the print medium corresponding to the acceleration start position 2.

For example, if the conveyance roller pair 13, 14 is located upstream (at a position farther from the print medium discharge port of the printing device 10) than the positions shown in FIGS. 5A and 5B, the acceleration start position 1 The size of the print medium corresponding to this may include up to A3 portrait.

Conversely, if the pair of transport rollers 13 and 14 are located downstream (closer to the print medium discharge port of the printing device 10) than the positions shown in FIGS. 5A and 5B, the acceleration start position The size of the print medium corresponding to 2 may include up to B4 portrait. As a result, a more appropriate acceleration start position can be set for various printing apparatuses 10 having different types of transport roller pairs.

Further, as for the types of printing media, there are those that easily generate paper dust and those that are difficult to generate paper dust. For printing media that are likely to generate paper dust, it is preferable that the rear end of the printing medium be quickly removed from the pair of transport rollers 13 and 14 of the printing device 10 after accelerating the rotational speed of the pair of switchback rollers 34.

Therefore, for example, the control unit 50 may change the acceleration start position described above depending on the type of print medium. For example, if the type of printing medium is likely to generate paper dust, set it to the acceleration start position 2 mentioned above, and if the type of printing medium does not easily generate paper dust, set it to the acceleration start position 1 mentioned above. You may also set it. Specifically, for example, a table may be set in the control unit 50 that associates the type of print medium with the acceleration start position. The type of print medium may be acquired by the control unit 50 from the print job, or may be input by the user on an operation panel (not shown). Thereby, an appropriate acceleration start position can be set depending on the type of print medium.

Regarding the print medium reversing device of the present invention, the following additional notes are further disclosed.
(Additional note)

In the print medium reversing device of the present invention, the control unit can change the acceleration start position so that the reversal margin time between print media becomes equal to or greater than a preset threshold.

Furthermore, in the print medium reversing device of the present invention, the control unit can change the acceleration start position with respect to the length of the print medium in the conveyance direction, depending on the aspect of the conveyance roller pair of the printing device.

Furthermore, in the print medium reversing device of the present invention, the control section can change the acceleration start position with respect to the length of the print medium in the conveyance direction, depending on the type of print medium.

Further, in the print medium reversing device of the present invention, the acceleration start position is set to a switchback path when the length of the print medium in the transport direction is longer than a predetermined length, compared to when the print medium is shorter than the predetermined length. It can be controlled to be on the downstream side.

1 Printing system 10 Printing device 11 Inkjet head 12 Platen rollers 13, 14 Conveying roller pair 15 Conveying motor 20 Print medium reversing device 21 Discharged paper conveying section 22 Reversing section 23 Introducing roller pair 24 Introducing motor 25 Face-up roller pair 26 Rising roller pair 27 Ascending motor 28 Discharging roller pair 29 Discharging motor 30 Post-processing device 31 Path switching flipper 32 Path switching solenoid 33 Reversing approach roller pair 34 Switchback roller pair 35 Switchback motor 36 Intermediate roller pair 37 Intermediate conveyance motor 38 Introduction sensor 39 Reversing sensor 40 Switchback sensor 41 Acceptance roller 42 Acceptance roller drive motor 43 Paper discharge motor 44 Reverse approach motor 50 Control unit RD Paper discharge route RI Reverse approach route RO Reverse exit route RS Reverse route

Claims (4)

a switchback path that receives the print medium conveyed by the pair of conveyance rollers, conveys the received print medium in a switchback manner, and transfers the received print medium to the downstream side;
a switchback roller section that is provided on the switchback path and switches back the print medium by reversing the rotation direction;
and a control unit that controls the rotational speed of the switchback roller unit,
The control unit accelerates the rotational speed of the switchback roller unit from the time when the accepted print medium is conveyed to a predetermined acceleration start position, and adjusts the acceleration start position to the length of the print medium in the conveyance direction. A print medium reversing device that changes the acceleration start position accordingly and changes the acceleration start position so that a reversal margin time between print media is equal to or greater than a preset threshold. a switchback path that receives the print medium conveyed by the pair of conveyance rollers, conveys the received print medium in a switchback manner, and transfers the received print medium to the downstream side;
a switchback roller section that is provided on the switchback path and switches back the print medium by reversing the rotation direction;
and a control unit that controls the rotational speed of the switchback roller unit,
The control unit accelerates the rotational speed of the switchback roller unit from the time when the accepted print medium is conveyed to a predetermined acceleration start position, and adjusts the acceleration start position to the length of the print medium in the conveyance direction. The printing medium reversing device changes the acceleration start position with respect to the length of the printing medium in the conveyance direction according to the aspect of the conveyance roller pair of the printing device. a switchback path that receives the print medium conveyed by the pair of conveyance rollers, conveys the received print medium in a switchback manner, and transfers the received print medium to the downstream side;
a switchback roller section that is provided on the switchback path and switches back the print medium by reversing the rotation direction;
and a control unit that controls the rotational speed of the switchback roller unit,
The control unit accelerates the rotational speed of the switchback roller unit from the time when the accepted print medium is conveyed to a predetermined acceleration start position, and adjusts the acceleration start position to the length of the print medium in the conveyance direction. The printing medium reversing device changes the acceleration start position with respect to the length of the printing medium in a conveying direction according to the type of the printing medium. The acceleration start position is such that when the length of the print medium in the conveyance direction is longer than a predetermined length, the acceleration start position is on the downstream side of the switchback path compared to when the print medium is shorter than the predetermined length. The print media reversing device according to claim 1 , wherein the print media reversing device is controlled.