JP7056280B2 - Printing equipment - Google Patents

Description

The present invention relates to a printing apparatus.

Conventionally, a technique for removing foreign matter adhering to the surface of a recording medium in a printing apparatus to perform printing has been proposed (see, for example, Patent Document 1). The technique described in Patent Document 1 is to bring a non-woven fabric formed in a loop shape into contact with the surface of a recording medium in order to remove foreign matter adhering to the printed surface of the recording medium. It is said that when such a technique is adopted, foreign matter can be easily removed due to the unevenness of the surface of the non-woven fabric, and foreign matter can be collected (retained) in the space formed between the fibers.

Japanese Unexamined Patent Publication No. 2017-197354

However, in the technique described in Patent Document 1, the case where the recording medium is reversely conveyed is not assumed. The inventor of the present invention has found that when the recording medium is reversely conveyed, a problem arises only by bringing the non-woven fabric formed in a loop shape into contact with the surface of the recording medium and removing the foreign matter.

Specifically, when the transport direction of the recording medium changes, the posture (shape) of the loop-shaped non-woven fabric changes. When transporting in the forward direction, the non-woven fabric is shelved to the downstream side in the forward direction, but when transported in the opposite direction, the non-woven fabric changes its posture and is shelved to the upstream side in the forward direction. When the posture of the non-woven fabric changes from the forward downstream side to the forward upstream side in this way, a part of the foreign matter collected by the non-woven fabric spills on the side opposite to the posture change direction (forward downstream side). It ends up. Then, the spilled foreign matter is collected again on the non-woven fabric by the reverse transfer, but the foreign matter collected at this time is conveyed to the bottom of the head as it is when the recording medium is conveyed in the forward direction again, and the nozzle surface is affected. There is a risk of damaging it.

The present invention has been made in view of such circumstances, and in a printing apparatus capable of transporting a recording medium in the forward direction and the reverse direction, the nozzle surface of the head is damaged by foreign matter generated due to switching of the transport direction. The purpose is to prevent this.

In order to achieve the above object, the printing apparatus according to the present invention includes a head that prints on a recording medium, a transport unit that transports the recording medium in the forward direction and the reverse direction opposite to the forward direction, and a head in the forward direction. It includes a foreign matter removing unit arranged on the upstream side and a control unit for controlling the head and the transporting unit. The foreign matter removing unit is attached to the support unit and the support unit, and is attached to the support unit and the printing surface of the recording medium. A flexible member in contact with the In the second process of stopping, the third process of transporting the recording medium in the forward direction by a distance equal to or greater than the distance from the foreign matter removing unit to the head located at the most downstream in the forward direction, and the third process. Next, the head and the transport unit are controlled so as to carry out the fourth process of resuming printing by the head.

When such a configuration is adopted, the forward transfer of the printing and recording medium is stopped, then the transfer is stopped after the recording medium is conveyed in the reverse direction, and then the transfer is stopped at a specific distance (the most downstream in the forward direction from the foreign matter removing portion). It is possible to carry out a processing group in which the recording medium is conveyed in the forward direction by a distance equal to or greater than the distance to the head to be located), and then printing by the head is restarted. That is, instead of restarting printing immediately after switching from reverse transport to forward transport of the recording medium, it is possible to restart printing after performing forward transport for a specific distance after switching. Therefore, even if foreign matter spills on the side opposite to the deformation direction (forward downstream side) of the foreign matter removing portion due to reverse transport, printing can be restarted after the foreign matter passes through the most downstream head. Therefore, it is possible to prevent the nozzle surface of the head from being damaged by such foreign matter.

In the printing apparatus according to the present invention, the control unit retracts the head from the print position to the retracted position between the first process and the second process, and retracts the head from the retracted position to the print position between the third process and the fourth process. Can be moved to.

In the printing apparatus according to the present invention, a rotating roller that rotates according to the recorded recording medium to be conveyed can be provided at a position facing the foreign matter removing portion across the recording medium. At this time, the distance between the support portion of the foreign matter removing portion and the rotating roller can be set to 3 mm or more and 5 mm or less.

In the printing apparatus according to the present invention, the length of the support portion of the recording medium in the transport direction can be set to 18 mm or more and 25 mm or less. Further, the length of the flexible member excluding the attachment portion to the support portion in the transport direction can be set to 35 mm or more and 45 mm or less.

The plan view which shows the layout of the printing apparatus which concerns on embodiment of this invention (the figure seen from the upper side). The front view (the view seen from the front side) which shows the whole structure of the printing apparatus which concerns on embodiment of this invention. The block diagram for demonstrating the structure of the foreign matter removing part of the printing apparatus which concerns on embodiment of this invention. Explanatory drawing for explaining the situation that foreign matter is generated by switching a sheet transport direction. The flowchart for demonstrating the flow of the foreign matter avoidance control by the control part of the printing apparatus which concerns on embodiment of this invention. The explanatory view for demonstrating each process of the foreign matter avoidance control by the control part of the printing apparatus which concerns on embodiment of this invention.

Hereinafter, embodiments of the printing apparatus according to the present invention will be described with reference to the drawings. The present invention is not limited by such embodiments.

FIG. 1 is a plan view showing the layout of the printing apparatus 1 according to the embodiment of the present invention. Further, FIG. 2 is a front view for explaining the overall configuration of the printing apparatus 1 shown in FIG. In the printing apparatus 1, the feeding unit 2, the process unit 3, and the winding unit 4 are arranged in the left-right direction on the front side of the apparatus, and the maintenance unit 5 is arranged on the rear side of the process unit 3, and the process unit of the process unit 3 is arranged. The 3U is integrally movable with respect to the maintenance unit 5. In these drawings and the drawings described later, a three-dimensional coordinate system corresponding to the left-right direction X, the front-back direction Y, and the vertical direction Z of the printing apparatus 1 is adopted.

As shown in FIG. 2, in the printing apparatus 1, the feeding unit 2 and the winding unit 4 have a feeding shaft 20 and a winding shaft 40, respectively. Then, both ends of the sheet S are wound around the feeding portion 2 and the winding portion 4 in a roll shape, and are stretched between them. The sheet S is conveyed from the feeding section 2 to the process section 3 along the path Pc stretched in this way, undergoes printing processing by the process unit 3U, and then conveyed to the winding section 4. The type of sheet S corresponding to the "recording medium" of the present invention is roughly classified into a paper type and a film type. Specific examples include high-quality paper, cast paper, art paper, coated paper and the like in the paper system, and synthetic paper, PET (Polyethylene terephthalate), PP (polypropylene) and the like in the film system. In the following description, of both sides of the sheet S, the surface on which the image is recorded is referred to as a front surface, while the surface on the opposite side thereof is referred to as a back surface.

The feeding unit 2 has a feeding shaft 20 around which the end of the sheet S is wound, and a driven roller 21 around which the sheet S drawn from the feeding shaft 20 is wound. The feeding shaft 20 is supported by winding the end of the sheet S with the surface of the sheet S facing outward. Then, by rotating the feeding shaft 20 clockwise on the paper surface of FIG. 2, the sheet S wound around the feeding shaft 20 is fed to the process unit 3 via the driven roller 21. Incidentally, the sheet S is wound around the feeding shaft 20 via a core tube (not shown) that can be attached to and detached from the feeding shaft 20. Therefore, when the sheet S of the feeding shaft 20 is used up, a new core tube around which the roll-shaped sheet S is wound can be attached to the feeding shaft 20 to replace the sheet S of the feeding shaft 20. It has become.

A foreign matter removing portion 50 for removing foreign matter adhering to the surface of the sheet S is provided between the driven roller 21 of the feeding portion 2 and the front drive roller 31 (described later) of the process portion 3. The configuration of the foreign matter removing unit 50 will be described in detail later. Further, at a position facing the foreign matter removing portion 50 with the sheet S interposed therebetween, a rotating roller 60 that is driven and rotated according to the sheet S to be conveyed is provided. The reference numeral Se in FIG. 2 is an edge sensor that detects the end of the sheet S in the width direction between the driven roller 21 and the front drive roller 31.

The process unit 3 appropriately processes the sheet S fed out from the feeding unit 2 by the process unit 3U arranged along the surface 30a of the platen drum 30 while supporting the sheet S fed out from the platen drum 30 by the surface 30a of the platen drum 30. The image is printed on the drum. In the process unit 3, front drive rollers 31 and rear drive rollers 32 are provided on both sides of the platen drum 30, and the sheet S conveyed from the front drive rollers 31 to the rear drive rollers 32 is supported by the platen drum 30. And receive the print of the image. The front drive roller 31 and the rear drive roller 32 function as a transport unit in the present invention, and operate based on an operation command sent from the control unit 70. As shown in FIG. 2, the front drive roller 31 and the rear drive roller 32 not only convey the sheet S in the forward direction D ₁ , but also rewind the sheet S in the reverse direction D ₂ opposite to the forward direction D ₁ . (Hereinafter, the front drive roller 31 and the rear drive roller 32 may be collectively referred to as a "transport unit").

The front drive roller 31 has a plurality of minute protrusions formed by thermal spraying on the outer peripheral surface, and winds the sheet S fed from the feeding portion 2 from the back surface side. Then, the front drive roller 31 rotates clockwise on the paper surface of FIG. 2 to convey the sheet S fed from the feeding portion 2 to the downstream side of the transport path (in the forward direction D ₁ ). A nip roller 31n is provided for the front drive roller 31. The nip roller 31n is in contact with the surface of the sheet S in a state of being urged toward the front drive roller 31, and sandwiches the sheet S with the front drive roller 31. As a result, the frictional force between the front drive roller 31 and the seat S is secured, and the seat S can be reliably conveyed by the front drive roller 31.

The platen drum 30 is a cylindrical drum rotatably supported around a rotation shaft 301 extending in the Y direction by a support mechanism (not shown), and is conveyed from the front drive roller 31 to the rear drive roller 32. Wrap the sheet S from the back side. The platen drum 30 receives a frictional force with the sheet S and rotates drivenly in the transport direction Ds of the sheet S, while supporting the sheet S from the back surface side on the front surface 30a. Incidentally, the process unit 3 is provided with driven rollers 33 and 34 that fold back the sheet S on both sides of the winding portion around the platen drum 30. Of these, the driven roller 33 winds the surface of the sheet S between the front drive roller 31 and the platen drum 30, and folds the sheet S back. On the other hand, the driven roller 34 winds the surface of the sheet S between the platen drum 30 and the rear drive roller 32, and folds the sheet S back. In this way, by folding back the sheet S on each of the upstream and downstream sides of the transport direction Ds with respect to the platen drum 30, it is possible to secure a long winding portion of the sheet S on the platen drum 30. Although FIG. 2 shows only the rotation direction (transport direction Ds) corresponding to the forward direction D ₁ , the platen drum 30 can also rotate in the direction corresponding to the reverse direction D ₂ .

The rear drive roller 32 has a plurality of minute protrusions formed by thermal spraying on the outer peripheral surface, and winds the sheet S conveyed from the platen drum 30 via the driven roller 34 from the back surface side. Then, the rear drive roller 32 rotates clockwise on the paper surface of FIG. 2 to convey the sheet S to the winding unit 4. A nip roller 32n is provided for the rear drive roller 32. The nip roller 32n is in contact with the surface of the sheet S in a state of being urged toward the rear drive roller 32, and sandwiches the sheet S with the rear drive roller 32. As a result, the frictional force between the rear drive roller 32 and the seat S is secured, and the seat S can be reliably conveyed by the rear drive roller 32.

In this way, the sheet S conveyed from the front drive roller 31 to the rear drive roller 32 is supported by the surface 30a of the platen drum 30. The process unit 3 is provided with a process unit 3U for printing a color image on the surface of the sheet S supported by the platen drum 30. The process unit 3U has a front plate and a back plate (not shown) provided in a pair of front and rear plates. Each plate has an arc shape along the surface 30a of the platen drum 30, and is connected to each other by a connecting member (not shown) to form a unit frame. Then, the components (print heads 36a to 36e, UV lamps 37a, 37b, head moving mechanism) of the process unit 3U are mounted on the unit frame as described below.

Four print heads 36a to 36d corresponding to cyan, magenta, black and yellow are arranged in the transport direction Ds in this color order. More specifically, these four print heads 36a to 36d are arranged radially from the rotation shaft 301 of the platen drum 30. Further, of the print heads 36a to 36d, the two print heads 36a and 36b arranged on the upstream side in the transport direction Ds are positioned with respect to the sheet S which is moved by one head moving mechanism and wound around the platen drum 30. Will be done. Further, the two print heads 36c and 36d arranged on the downstream side are also moved by another head moving mechanism and positioned with respect to the sheet S wound around the platen drum 30. Then, by moving and positioning the four print heads 36a to 36d by these two head movement mechanisms, the distance between the nozzle tip of the nozzle surface of the print heads 36a to 36d and the sheet S, that is, the so-called paper gap, is appropriate. It is possible to set it to a value. In this way, the print heads 36a to 36d eject ink to the sheet S wound around the outer peripheral portion of the platen drum 30 with the paper gap adjusted, thereby forming a color image on the surface of the sheet S. do.

As the liquid such as the ink and the recording liquid used in the print heads 36a to 36d, UV (ultraviolet) ink (photocurable ink) that is cured by irradiating with ultraviolet rays (light) is used. Therefore, in the process unit 3U, UV lamps 37a and 37b are provided in order to cure the ink and fix it on the sheet S. This ink curing is performed in two stages, temporary curing and main curing. A UV lamp 37a for temporary curing is arranged between each of the plurality of print heads 36a to 36d. That is, the UV lamp 37a cures (temporarily cures) the ink to the extent that the shape of the ink does not collapse by irradiating it with relatively weak ultraviolet rays, and does not completely cure the ink. On the other hand, a UV lamp 37b for main curing is provided on the downstream side of the transport direction Ds with respect to the plurality of print heads 36a to 36d. That is, the UV lamp 37b completely cures (mainly cures) the ink by irradiating it with ultraviolet rays stronger than the UV lamp 37a. By executing the temporary curing and the main curing in this way, the color image formed by the plurality of print heads 36a to 36d can be fixed on the surface of the sheet S.

Further, a print head 36e is provided on the downstream side of the transport direction Ds with respect to the UV lamp 37b. The print head 36e faces the surface of the sheet S wound around the platen drum 30 with a slight clearance, and ejects transparent UV ink onto the surface of the sheet S by an inkjet method. That is, the transparent ink is further ejected to the color images formed by the print heads 36a to 36d for four colors. The print head 36e is independently moved and positioned by a head moving mechanism different from the head moving mechanism described above, and the paper gap is set to an appropriate value.

As described above, the print heads 36a to 36e, the UV lamps 37a and 37b, and the head moving mechanism are mounted on the unit frame to form the process unit 3U. Then, during normal operation, that is, during the printing process, the printer is positioned between the feeding unit 2 and the winding unit 4 as shown by a solid line in FIG. On the other hand, when performing maintenance operations of the process unit 3U, for example, wiping processing, capping processing, etc. for the print heads 36a to 36e, the process unit 3U is a slide drive mechanism (not shown) as shown by the alternate long and short dash line in FIG. Is moved to the maintenance unit 5.

Returning to FIG. 2, the configuration description of the process unit 3 and the winding unit 4 will be continued. In the process unit 3, a UV lamp 38 is provided on the downstream side of the transfer direction Ds with respect to the print head 36e. The UV lamp 38 completely cures (mainly cures) the transparent ink ejected by the print head 36e by irradiating it with strong ultraviolet rays. As a result, the transparent ink can be fixed on the surface of the sheet S.

The sheet S on which the color image is formed by the process unit 3 is conveyed to the winding unit 4 by the rear drive roller 32. In addition to the winding shaft 40 around which the end of the sheet S is wound, the winding unit 4 has a driven roller 41 for winding the sheet S from the back surface side between the winding shaft 40 and the rear drive roller 32. The take-up shaft 40 winds up and supports the end of the sheet S with the surface of the sheet S facing outward. That is, when the take-up shaft 40 rotates clockwise on the paper surface of FIG. 2, the sheet S conveyed from the rear-drive roller 32 is taken up by the take-up shaft 40 via the driven roller 41. Incidentally, the sheet S is wound around the winding shaft 40 via a core tube (not shown) that is removable from the winding shaft 40. Therefore, when the sheet S wound around the take-up shaft 40 is full, the sheet S can be removed together with the core tube.

Here, the configuration of the foreign matter removing unit 50 of the printing apparatus 1 according to the present embodiment will be described with reference to FIG. 3 and the like.

As described above, the foreign matter removing unit 50 removes foreign matter adhering to the surface of the sheet S, and is arranged on the upstream side of the print heads 36a to 36e in the forward direction D1 (see FIG. ₂ ). The foreign matter removing portion 50 has a support portion 51 and a flexible member 52 attached to the support portion 51 and in contact with the surface (printing surface) of the sheet S.

The support portion 51 is fixed in a state of being arranged vertically above the transport path of the sheet S. The configuration of the support portion 51 is not particularly limited as long as it has a function of supporting the flexible member 52. As the flexible member 52, a non-woven fabric formed by partially adhering fibers, a felt formed by entwining fibers into a cloth shape, a cloth formed by weaving or knitting fibers, or the like can be adopted. can. As shown in FIG. 3, the flexible member 52 is formed in a loop shape so as to exhibit a substantially U shape in a side view, and when the sheet S is conveyed in the forward direction D ₁ , FIG. 4 (A). ) And as shown in FIG. 4 (C), when shelving to the downstream side of the forward direction D ₁ and transporting the sheet S in the reverse direction D ₂ , the forward direction D ₁ upstream side as shown in FIG. 4 (B). The posture is changed immediately even when shelving and switching the transport direction of the sheet S.

In the present embodiment, the length A (see FIG. 3) of the sheet S of the support portion 51 of the foreign matter removing portion 50 in the transport direction is set to 18 mm or more and 25 mm or less. If the length A is less than 18 mm, it takes time to switch the posture of the flexible member 52 when the transport direction of the sheet S is switched from the reverse direction D ₂ to the forward direction D ₁ , and further, the removal rate of foreign matter is high. Is not preferable because it decreases. Further, when the length A exceeds 25 mm, it takes time to switch the posture of the flexible member 52 when the transport direction of the sheet S is switched from the forward direction D ₁ to the reverse direction D ₂ , and further, foreign matter is removed. It is not preferable because the rate decreases.

Further, in the present embodiment, the length B (see FIG. 3) of the flexible member 52 in the transport direction of the flexible member 52 excluding the portion where the foreign matter removing portion 50 is attached to the support portion 51 is set to 35 mm or more and 45 mm or less. It is set. If the length B is less than 35 mm, it takes time to switch the posture of the flexible member 52 when the transport direction of the sheet S is switched from the forward direction D ₁ to the reverse direction D ₂ , and further, the removal rate of foreign matter is high. Is not preferable because it decreases. Further, when the length B exceeds 45 mm, it takes time to switch the posture of the flexible member 52 when the transport direction of the sheet S is switched from the forward direction D ₁ to the reverse direction D ₂ , and further, foreign matter is removed. It is not preferable because the rate decreases.

Further, in the present embodiment, the distance C (see FIG. 2) between the support portion 51 of the foreign matter removing portion 50 and the rotating roller 60 is set to 3 mm or more and 5 mm or less. When the distance C is less than 3 mm, the posture of the flexible member 52 changes when the transport direction of the sheet S is switched from the forward direction D ₁ to the reverse direction D ₂ (or from the reverse direction D ₂ to the forward direction D ₁ ). It takes time to switch, and the removal rate of foreign matter is lowered, which is not preferable. Further, when the distance C exceeds 5 mm, it takes time to switch the posture of the flexible member 52 when the transport direction of the sheet S is switched from the forward direction D ₁ to the reverse direction D ₂ , and further, the removal rate of foreign matter is high. Is not preferable because it decreases.

Next, foreign matter avoidance control by the control unit 70 of the printing apparatus 1 according to the present embodiment will be described.

The control unit 70 in the present embodiment is a head moving mechanism for the print heads 36a to 36e so as to prevent the nozzle surfaces of the print heads 36a to 36e from being damaged by foreign matter generated due to the switching of the transport direction of the sheet S. The actuator (not shown) and the front drive roller 31 and the rear drive roller 32 (conveying unit) are controlled.

Here, a situation in which a foreign substance is generated due to the switching of the transport direction of the sheet S will be described with reference to FIG. First, as shown in FIG. 4A, when the sheet S is conveyed in the forward direction D ₁ , the foreign matter P existing on the surface of the sheet S is removed by the flexible member 52 of the foreign matter removing portion 50. The foreign matter P'that has not been removed is sent to the downstream side of the flexible member 52 in the forward direction D ₁ . Since the foreign matter P'at this stage is very small in size, it does not come into contact with the nozzle surfaces of the print heads 36a to 36e. When the transport direction of the sheet S is switched to the reverse direction D ₂ in this state, as shown in FIG. 4 (B), a plurality of foreign substances P'that were not removed during the forward transport are united to form the flexible member 52. Forward direction D ₁ May accumulate on the downstream side. Further, as the transport direction is switched, the foreign matter P accumulated in the forward direction D ₁ upstream side of the flexible member 52 may spill to the forward direction D ₁ downstream side. After that, when the transport direction of the sheet S is switched to the _forward direction D ₁ again, as shown in FIG. The spilled foreign matter P may be sent to the downstream side and come into contact with the nozzle surface of the print heads 36a to 36e. The control unit 70 in the present embodiment controls the transport unit and the like so as to prevent the nozzle surfaces of the print heads 36a to 36e from being damaged by the foreign substances P and P'generated in this way.

FIG. 5 is a flowchart for explaining the flow of foreign matter avoidance control by the control unit 70, and FIG. 6 is an explanatory diagram for explaining each process of foreign matter avoidance control by the control unit 70.

_First , as shown in FIGS. 5 and 6A, the control unit 70 performs printing by the print heads 36a to 36e while sequentially transporting the sheets S (transporting in the forward direction D1). Etc. (printing process: S1). Next, as shown in FIGS. 5 and 6B, the control unit 70 controls the transfer unit and the like so as to stop printing and forward transfer (print transfer stop process: S2), and then the print heads 36a to The actuator of the head moving mechanism is controlled so that the 36e is retracted from the print position to the retracted position (head raising process: S3). The print transfer stop process S2 corresponds to the first process in the present invention.

Next, as shown in FIGS. 5 and 6 (C), the control unit 70 controls the transport unit so that the sheet S is reversely transported (transported in the reverse direction D ₂ ) by a predetermined distance (reverse transport processing). : S4), as shown in FIGS. 5 and 6 (D), the transport unit is controlled so as to stop the reverse transport when the reverse transport is performed for a predetermined distance (reverse transport stop processing: S5). The reverse transfer distance in the reverse transfer process S4 may be appropriately set according to the purpose of the reverse transfer (for example, reprinting after printing is stopped, periodic cleaning, printing to eliminate margins between print jobs, etc.). can. The reverse transfer process S4 and the reverse transfer stop process S5 correspond to the second process in the present invention. Due to the reverse transport process S4, the foreign matter P'that was not removed and the foreign matter P that spilled due to the switching of the transport direction are accumulated on the forward side D ₁ downstream side of the flexible member 52 of the foreign matter removing portion 50. (See FIG. 6 (D)).

Next, as shown in FIGS. 5 and 6 (E), the control unit 70 has a specific distance L'(a distance L or more from the foreign matter removing unit 50 to the print head 36e located at the most downstream position in the forward direction D ₁ ). The transport unit is controlled so that the sheet S is sequentially transported by the distance) (forward transport process: S6). The forward transfer process S6 corresponds to the third process in the present invention. Due to the forward transfer process S6, the foreign substances P and P'pass below the print head 36e located at the most downstream position (see FIG. 6E). After that, the control unit 70 controls the transport unit so as to stop the forward transport of the seat S (sequential transport stop process: S7).

Next, as shown in FIGS. 5 and 6 (F), the control unit 70 controls the actuator of the head movement mechanism so as to move the print heads 36a to 36e from the retracted position to the print position (head lowering process: S8), the transport unit and the like are controlled so as to perform printing by the print heads 36a to 36e while sequentially transporting the sheets S (printing restart processing: S9). The print restart process S9 corresponds to the fourth process in the present invention.

In the printing apparatus 1 according to the above-described embodiment, printing and forward transfer are stopped, then the reverse transfer of the sheet S is stopped, and then the reverse transfer is stopped, and then a specific distance L'(foreign matter removing unit 50 to forward D). It is possible to carry out a processing group in which the sheet S is sequentially conveyed by the distance L or more to the print head 36e located at the most downstream position in ₁ and then printing by the print heads 36a to 36e is restarted. That is, instead of restarting printing immediately after switching from reverse transport to forward transport of the sheet S, it is possible to restart printing after performing forward transport for a specific distance L'after switching. Therefore, even if the foreign matter P spills on the side opposite to the deformation direction (forward direction D ₁ downstream side) of the foreign matter removing portion 50 due to the reverse transport, the foreign matter P passes through the most downstream print head 36e. Since printing can be restarted from, it is possible to prevent the nozzle surfaces of the print heads 36a to 36e from being damaged by such foreign matter P.

The present invention is not limited to the above embodiments, and those having a design modification appropriately by those skilled in the art are also included in the scope of the present invention as long as they have the features of the present invention. .. That is, each element included in the embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those exemplified, and can be appropriately changed. Further, the elements included in such an embodiment can be combined as much as technically possible, and the combination thereof is also included in the scope of the present invention as long as the features of the present invention are included.

1 ... Printing device, 31 ... Front drive roller (conveying unit), 32 ... Rear drive roller (conveying unit), 36a, 36b, 36c, 36d, 36e ... Printing head (head), 50 ... Foreign matter removing unit, 51 ... Support Part, 52 ... Flexible member, 60 ... Rotating roller, 70 ... Control part, A ... Length of the support part in the transport direction, B ... In the transport direction of the flexible member excluding the portion attached to the support part. Length, C ... distance between support and rotating roller, D ₁ ... forward direction, D ₂ ... reverse direction, S ... sheet (recording medium), S2 ... print transfer stop processing (first processing), S4 ... Reverse transfer process (second process), S5 ... Reverse transfer stop process (second process), S6 ... Forward transfer process (third process), S9 ... Print restart process (fourth process)

Claims (6)

A head for printing on a recording medium, a transport unit for transporting the recording medium in the forward direction and the reverse direction opposite to the forward direction, and a foreign matter removing unit arranged on the upstream side of the head in the forward direction. A printing apparatus including a control unit that controls the head and the transport unit.
The foreign matter removing portion includes a support portion and a flexible member attached to the support portion and in contact with the printing surface of the recording medium while transporting the recording medium in the forward direction and the reverse direction. Have and
The control unit has a first process of stopping the printing and the transfer of the recording medium in the forward direction, and a second process of stopping the transfer after the recording medium is conveyed in the reverse direction after the first process. Then, following the second process, the third process of transporting the recording medium in the forward direction by a distance equal to or greater than the distance from the foreign matter removing unit to the head located at the most downstream position in the forward direction, and the third process. A printing apparatus that controls the head and the transport unit so as to perform a fourth process of resuming printing by the head. The control unit retracts the head from the print position to the retracted position between the first process and the second process, and prints the head from the retracted position between the third process and the fourth process. The printing apparatus according to claim 1, which is moved to a position. The printing apparatus according to claim 1 or 2, wherein a rotating roller that rotates in accordance with the conveyed recording medium is provided at a position facing the foreign matter removing portion with the recording medium interposed therebetween. The printing apparatus according to claim 3, wherein the distance between the support portion and the rotating roller is 3 mm or more and 5 mm or less. A head for printing on a recording medium, a transport unit for transporting the recording medium in the forward direction and the reverse direction opposite to the forward direction, and a foreign matter removing unit arranged on the upstream side of the head in the forward direction. A printing apparatus including a control unit that controls the head and the transport unit.
The foreign matter removing portion includes a support portion and a flexible member attached to the support portion and in contact with the printing surface of the recording medium while transporting the recording medium in the forward direction and the reverse direction. Have and
The control unit has a first process of stopping the printing and the transfer of the recording medium in the forward direction, and a second process of stopping the transfer after the recording medium is conveyed in the reverse direction after the first process. Then, following the second process, the third process of transporting the recording medium in the forward direction by a distance equal to or greater than the distance from the foreign matter removing unit to the head located at the most downstream position in the forward direction, and the third process. Then, the head and the transport unit are controlled so as to carry out the fourth process of resuming printing by the head.
A printing apparatus in which the length of the support portion in the transport direction of the recording medium is 18 mm or more and 25 mm or less. A head for printing on a recording medium, a transport unit for transporting the recording medium in the forward direction and the reverse direction opposite to the forward direction, and a foreign matter removing unit arranged on the upstream side of the head in the forward direction. A printing apparatus including a control unit that controls the head and the transport unit.
The foreign matter removing portion includes a support portion and a flexible member attached to the support portion and in contact with the printing surface of the recording medium while transporting the recording medium in the forward direction and the reverse direction. Have and
The control unit has a first process of stopping the printing and the transfer of the recording medium in the forward direction, and a second process of stopping the transfer after the recording medium is conveyed in the reverse direction after the first process. Then, following the second process, the third process of transporting the recording medium in the forward direction by a distance equal to or greater than the distance from the foreign matter removing unit to the head located at the most downstream position in the forward direction, and the third process. Then, the head and the transport unit are controlled so as to carry out the fourth process of resuming printing by the head.
A printing apparatus having a length of the flexible member excluding a portion attached to the support portion in the transport direction of 35 mm or more and 45 mm or less.

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