JPH10157230A - Medium-holding apparatus of ink-jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an outer circumferential face of a drum from being stained by ink and at the same time hold a printing medium surely, by providing a drum in which an internal space is partitioned to a plurality of negative pressure generation chambers, discharging the air in each negative pressure generation chamber interlockingly with the arrival of the printing medium, thereby turning the interior to a negative pressure, and sucking and holding the printing medium. SOLUTION: In association with a printing medium M sent to a drum 10, a damper is opened and an opening.closing mechanism 25 is operated, whereby each of shutters 18 set at the side of an end face of the drum 10 is sequentially opened from a downstream one to an upper stream one in a rotational direction. When the shutter 18 at the downstream is opened to open a suction port 14, the air of a corresponding negative pressure generation chamber (16-1) is sucked by a suction fan outside through the suction port 14, and a negative pressure is established in the negative pressure generation chamber (16-1). Accordingly, the printing medium M is sucked and held through a suction hole 12. The printing medium M held at an outer circumferetial face 11 of the drum is printed in colors when the ink is blown from each color ink-jet nozzle 200.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium holding device for an ink jet printer which is held on a drum rotatable at a constant peripheral speed and which can print while spraying ink from an ink jet nozzle onto a printing medium rotating with the drum.

[0002]

2. Description of the Related Art A nozzle unit for each color is reciprocated over the entire length in a row direction, and printing is performed during each forward movement to print one line, and after one line printing, a printing medium (plain paper, OHP paper, etc.). Compared to a so-called serial type ink-jet printer, M can be fed one line in the column direction and repeated, so that the printing speed can be greatly increased and continuous printing operation can be performed on a large number of sheets. The present applicant has proposed an ink-jet printer capable of achieving a great reduction in size (for example, Japanese Patent Application No. 8-296959).

That is, in FIG. 7, a drum 10 is rotatable at a constant peripheral speed and can hold a print medium M on an outer peripheral surface 11 thereof. Rotation of this drum 10 (Y)
A nozzle unit 200 for each color is provided in the direction.

[0004] Therefore, an integrated nozzle unit 200 for each color or an integrated nozzle unit 200 for each color in which a plurality of nozzle unit elements are arranged in the row direction (for example, between the ink jet nozzles). Print medium M rotating while moving back and forth by the pitch
Ink can be printed in the row direction by spraying ink from the inkjet nozzles 207 for each color, and can be printed in the column direction while utilizing the rotation of the drum 10 during the forward movement of the pitch between the inkjet nozzles. That is, since the line-direction printing and the column-direction printing can proceed simultaneously, the printing speed can be greatly increased.

[0005] Further, since the nozzle unit 200 for each color and the ink tank (ink cassette) 213 for each color are arranged at a separated position, the nozzle unit 20 for each color is provided.
0 can be lightened, and the reciprocating movement speed in the row direction can be greatly increased. This further promotes higher printing speed, and the capacity of the ink tank (ink cassette) 213 for each color can be greatly increased. Can be continuously printed.

In order to realize these, one side (right side in the figure) of the drum 10 is provided with a feeding means 60 and a medium feeding means 90.
The other (left) side is provided with a medium peeling unit 140, a medium discharging / conveying unit 160, and a direction switching unit 190.

The feeding means 60 can selectively feed the printing medium M one by one from one of the cassette feeding means 71 and the manual feeding means 61. The medium supply means 90 feeds the fed print medium M to the drum 1 at a predetermined timing.
Feed to the 0 side. The medium peeling means 140 peels the print medium M from the drum 10 after printing, and
Numeral 0 discharges and conveys the separated print medium M to the left in FIG. The direction switching unit 190 selectively switches between the discharge tray 192 and the upper discharge tray 193. In this manner, since the feeding, supply, holding, printing, peeling, and discharging and conveying of the print medium M can be continuously performed, multicolor printing of, for example, 20 sheets or more in A4 size can be performed in one minute.

[0008]

By the way, in order to further increase the printing speed of the newly proposed printer, the printing medium M is rapidly moved to the outer peripheral surface 11 of the drum while the drum 10 is kept rotating without stopping. In addition, it is necessary that the sheet be held securely and released after printing. Also,
To further improve the print quality, it is necessary to prevent the drum outer peripheral surface 11 holding the print medium M from being stained with ink from the inkjet nozzle 207. SUMMARY OF THE INVENTION It is an object of the present invention to provide a medium holding device for an ink jet printer capable of quickly and reliably holding a printing medium on a rotating drum and releasing holding after printing while preventing the outer peripheral surface of the drum from being stained with ink. It is in.

[0009]

According to a first aspect of the present invention, there is provided an ink jet printer which is held on a drum rotatable at a constant peripheral speed and is capable of printing while spraying ink from an ink jet nozzle onto a print medium rotating with the drum. A medium holding device, wherein a plurality of negative pressure generating chambers are formed in a drum by partitioning the inner space of the drum with radially extending partitions, and a plurality of suction holes radially penetrating the inside and outside of the drum into each negative pressure generating chamber. A plurality of suction ports for communicating each negative pressure generation chamber and the outside and a shutter capable of opening and closing each suction port are provided on the end face side of the drum, and each shutter is provided on the stationary side by using the rotation of the drum. An opening / closing mechanism that can be opened and closed sequentially from the downstream side to the upstream side in the rotation direction, and a suction fan that sucks air in the negative pressure generation chamber through an open suction port are provided. It was formed to be a negative pressure suction holding the print medium to the drum outer peripheral surface by using, characterized in that.

In the case of this invention, when the opening and closing mechanism is operated in accordance with the printing medium sent to the drum while the suction fan is rotated, each shutter provided on the end face side of the drum rotates downstream in the rotation direction. Open from the side to the upstream side. That is, the shutters are sequentially opened in the reverse order of the rotation direction.

Here, when the downstream shutter is opened and the suction port is opened, the air in the corresponding negative pressure generation chamber is sucked out through the suction port, and a negative pressure is generated in the negative pressure generation chamber. Is established. Therefore, the portion (front end side) of the printing medium that reaches the position facing the suction hole penetrating the negative pressure generation chamber into and out of the drum is held by suction through the suction hole.

The negative pressure is also generated in the negative pressure generating chambers on the upstream side in the rotational direction sequentially through the opposed suction holes at the rear side from the leading end side of the print medium, so that the negative pressure is applied to the outer peripheral surface of the drum. Adsorbed and held.

As described above, since a negative pressure is established in each of the negative pressure generating chambers in a state where the corresponding suction holes are covered with the printing medium, foreign matter (for example, ink in the ink jet nozzle) is formed through the suction holes. ) Is not sucked, and the outer peripheral surface of the drum can be prevented from being soiled.

According to a second aspect of the present invention, there is provided a medium holding apparatus for an ink jet printer, wherein a total opening area of each of the suction ports is larger than a total opening area of each of the suction holes.

In this case, the amount of air sucked out of the internal space of the drum through each suction port is larger than the amount of air flowing into the internal space of the drum through each suction hole. The same effect as that of the invention can be obtained, and a negative pressure can be more reliably formed in the internal space of the drum.

According to a third aspect of the present invention, the printing medium is contacted with the outer peripheral surface of the drum and is moved from the front end side to the rear end side of the printing medium which is held by the negative pressure suction on the outer peripheral surface of the drum with the rotation of the drum. This is a medium holding device of an ink jet printer provided with a rubber roller.

In the case of this invention, even if the printing medium is attracted to the outer peripheral surface of the drum under a negative pressure while the printing medium is loosened, etc.
The slack is extended by a rubber roller. Therefore, the same effect as in the case of the invention described in claim 1 can be obtained, and the print medium can be adhered without wrinkles or the like.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. This inkjet printer is shown in FIG.
4, a plurality of negative pressure generating chambers (16-1, 16-2, 16-3), a suction hole 12, a suction port 14, and a shutter 18 are provided on the drum 10 side, and open and closed on the stationary side. A mechanism 25 and a suction fan 32 are provided, and each of the shutters 18 is sequentially opened from the downstream side in the rotation direction (Y) of the drum 10 to open each of the negative pressure generation chambers (16-1, 16-2, 16-3).
Is formed so as to be able to sequentially execute the generation of the negative pressure in the reverse of the arrangement order in the rotation direction (Y).

The ink jet printer has the same structure as that of the prior proposal (Japanese Patent Application No. 8-296959). Further, in this embodiment, mechanical holding is introduced as an auxiliary means.

As shown in FIG. 1A, the drum 10 has a partition 16 (17-1, 17) whose inner space 16 extends in the radial direction.
−2, 17-3, 17-4) and a plurality of (three in this embodiment) divided into a plurality (three) of negative pressure generation chambers (16-1, 16-2, 16). -3) is formed.

A plurality of suction holes 12 are formed on the outer peripheral surface 11 of the drum 10 so as to penetrate the negative pressure generating chambers (16-1, 16-2, 16-3) in and out. In this embodiment, each suction hole 12 is formed in a width dimension range smaller than the minimum width of the print medium M to be used.

Further, the end face of the drum 10 (side end plate 15
R), as shown in FIG. 2, each negative pressure generating chamber (16-1,
16-2, 16-3) and a plurality of suction ports 14 communicating with the outside are provided. The total opening area of each suction port 14 is
The total opening area of the suction holes 12 is set to be larger than the total opening area.

A corresponding suction port 34 is fixedly disposed on the bracket 5R in the main body case 1 corresponding to each suction port 14. The suction fan 32 is connected to the corresponding suction port 34 of the bracket 5R via a duct 35.

The suction fan 32 removes air in each of the negative pressure generating chambers (16-1, 16-2, 16-3) of the rotating drum 10 through the corresponding suction port 34 and each suction port 14. Each of the negative pressure generating chambers (16-1, 16-2, 16-3) sucked in
Means to establish a negative pressure in the interior. In this embodiment, a damper 38 that can open and close a discharge port 32 </ b> E for discharging suction air of the suction fan 32 is provided. This damper 38
Is opened and closed by a damper opening and closing mechanism 37.

The damper 38 is rotatably supported below the suction fan 32 via a pin 38P. As shown in FIG. 4, the damper opening / closing mechanism 37 is formed by an actuator 39 connected to a rear end portion 38B of the damper 38.

The discharge port 32E of the suction fan 32 is opened by driving the actuator 39 to open and rotating the damper 38 clockwise from the closed position shown by the solid line in FIG. Actuator 39 is closed to drive damper 3
By returning 8 to the closed position, the discharge port 32E of the suction fan 32 is closed.

In this embodiment, the suction fan 32
The duct 35 and the like form a negative pressure establishing means 31. Drum 10 (15R) and negative pressure establishing means 30 (5R)
Means that they approach in the drum axis direction but do not contact. The side end plate (end surface) 15L is a blind plate.

The shutter 18 is provided on the end surface (side end plate 15R) of the drum 10 so as to open and close the suction port 14. More specifically, the shutter 18 has a size capable of closing the suction port 14, and has a drum-side end portion rotatably provided via a pin 18 </ b> P.

The opening and closing mechanism 25 includes a normally closing mechanism (26),
Release mechanism 27, release lock mechanism 28, lock release mechanism 2
9, each shutter 18 is formed so as to be able to be sequentially opened and closed from the downstream side to the upstream side in the rotation direction by utilizing the rotation of the drum 10.

The normally closing mechanism is a means for constantly positioning and holding the shutter 18 at a position where the suction port 14 is closed, and is formed of a spring 26 in this embodiment. The release mechanism 27 includes an operating pin 27AP, a drive lever 2
7L, the actuator 18 includes an actuator 27A, and is configured to be able to open the shutter 18 against the urging force of the spring 26.

The release lock mechanism 28 includes a lock lever 28L (rotating pin 28P) and a spring 28SP, and is formed so that the shutter 18 can be locked in an open state. The lock release mechanism 29 includes an operating pin 29AP, a drive lever 29L, and an actuator 29A, and is formed to release an open lock state of the shutter 18 by the open lock mechanism 28.

Therefore, when the actuator 27A is driven to project the operation pin 27AP toward the drum end surface (15R) via the drive lever 27L, the collision portion 18K1 of the shutter 18 which rotates together with the drum 10 contacts the operation pin 27AP. And rotates relative to the drum 10 in the opening direction.

When the shutter 18 is rotated to the position shown by the two-dot chain line in FIG. 1, the engaging portion 18K2 of the shutter 18 engages with the lock lever 28L and disengages with the operating pin 27AP. Is done. As a result, the shutter 18 is locked in the open state.

When the actuator 29A is driven to project the operating pin 29AP toward the drum end surface (15R) via the driving lever 29L, the lock lever 28L, which rotates together with the drum 10, comes into contact with the operating pin 29AP and the shutter 18 Release the engagement relationship with. Thus, the shutter 18 is kept in the closed state by the always closing mechanism (26). In FIG. 2, 10S is a rotation axis of the drum 10, and 100 is a detection sensor for detecting the position of the drum 10 in the rotation direction.

Also, the holding claw holding means 4 as an auxiliary means
As shown in FIGS. 5 (A) and 5 (B) and FIGS. 6 (A) and 6 (B), reference numeral 1 denotes a holding claw 42, a constantly holding mechanism 43, a normally open lock mechanism 44, a lock release mechanism 45, and a lock return mechanism 4.
6, a clamping claw 42, a constant clamping mechanism 43, and a constantly releasing lock mechanism 44 are mounted on one end of the movable drum 10, and a lock release mechanism 45 and a lock return mechanism 46 are stationary main body cases. 1 is attached to a bracket (not shown). The lock release mechanism 45 and the lock return mechanism 46 are connected to the drum 10
Is formed so as to engage with the always-holding mechanism 43 and the always-release locking mechanism 44 while holding and releasing the holding claws 42 while skillfully utilizing the rotational movement of the holding claw 42.

The holding claws 42 are formed so that the printing medium M can be held on the outer peripheral surface 11 of the drum 10. In particular,
As shown in FIGS. 6A and 6B, the holding claw 42 is
F, an engaging portion 42C, and a sector gear 42G.
It is attached so that it can rotate around P. This claw 42F
, The peripheral portion (for example, the leading end) of the print medium M is sandwiched between the drum outer peripheral surfaces 11.

The pinching mechanism 43 includes a lever 43L (a base 43B and a tip 43B) rotatable about a pin 43P.
F), a sector gear 43G provided at the distal end portion 43F and meshing with the sector gear 42G, and a spring 43SP stretched between the base end portion 43B and the fixed portion 43R. The urging force of the spring 43SP ( Using the pulling force), the holding claw 42 is always kept in the holding state shown by the two-dot chain line in FIG.

The always-release lock mechanism 44 comprises a lock lever 44L which can rotate about a pin 44P. An engagement groove 44C of the lock lever 44L can be engaged with and separated from an engagement portion 42C of the holding claw 42. Formed, both 44C, 42
6A, the holding claw 42 is always lockable in the holding and releasing state shown by the solid line in FIG.

The lock release mechanism 45 includes a stationary side pin 45.
Pivotable lever (tip 45F, base 4
5B) It consists of 45L and actuator 45A. When the lever 45L is rotated clockwise around the pin 45P by the actuator 45A, the distal end 45F formed of the pin engages with the proximal end 44B of the lock lever 44L that has moved with the rotation of the drum 10. I do. Then, the lock lever 44L rotates clockwise, and the holding claw 42 is rotated.
The engagement with (42C) is released. Therefore, the holding claws 42
Is in a state where it can be held by the urging force of the spring 43SP. That is, the constantly released lock state can be released.

As shown in FIG. 6A, the lock return mechanism 46 comprises a lever 46L (a distal end 46F and a proximal end 46B) that can rotate about a stationary pin 46P, and an actuator 46A. When the lever 46L is rotated clockwise around the pin 46P by the actuator 46A, the tip portion 46F formed of the pin of the lever 46L is rotated.
43L which has moved with the rotation of the drum 10
And the holding claws 42 can be brought into a holding release state shown by a two-dot chain line via the sector gears 43G and 42G. Therefore, the engaging portion 42C of the holding claw 42 is engaged with the engaging groove 44C of the lock lever 44L (44F). In other words, the pinching claw 42 can be returned to the constantly pinching locked state.

Next, the operation of this embodiment will be described. When the damper 38 is opened in accordance with the print medium M sent to the drum 10 and the opening / closing mechanism 25 is operated, each shutter 18 provided on the end face (15R) side of the drum 10 moves upstream from the downstream in the rotational direction. It is sequentially opened toward the side. That is, the shutters 18 are sequentially opened in the reverse order of the rotation direction.

Here, when the shutter 18 on the downstream side is opened and the suction port 14 is opened, the air in the corresponding negative pressure generation chamber (16-1) passes through the suction port 14 and the suction fan 32.
Is drawn out to the outside, and the negative pressure generation chamber (16-
A negative pressure is established within 1). Therefore, the portion (front end side) of the printing medium M that has reached the position facing the suction hole 12 penetrating into and out of the drum of the negative pressure generation chamber (16-1) is suction-held by the negative pressure via the suction hole 12. You.

The negative pressure generating chambers (16-2, 16-3) on the upstream side in the rotation direction also sequentially pass through the suction holes 12 on the rear side from the leading end side of the print medium M. Is generated, the negative pressure suction is held on the drum outer peripheral surface 11.

As described above, each negative pressure generation chamber (16-1, 1)
6-2, 16-3), the corresponding suction holes 12 have the printing medium M
Since a negative pressure is established in the state covered with
2 through a foreign matter [eg, an inkjet nozzle (20
7) does not suck in)
It is possible to prevent the drum outer peripheral surface 11 and the like from being soiled.

At this time, since the leading end of the print medium M is held by the holding claws 42 of the holding claw holding means 41, the printing medium M is more securely and stably held on the drum outer peripheral surface 11.

In this way, ink is sprayed from the ink jet nozzles (207) of each color onto the print medium M held on the drum outer peripheral surface 11 to perform color printing.

After the color printing, the mechanical holding by the clamping claw holding means 41 is released simultaneously with the release of the negative pressure suction holding of the print medium M by the negative pressure generating chamber 16-1.

According to this embodiment, a plurality of negative pressure generating chambers (16-1, 16-2, 16) are provided on the drum 10 side.
-3), the suction hole 12, the suction port 14, and the shutter 18 are provided, and the opening / closing mechanism 25 and the suction fan 32 are provided on the stationary side, and the opening of each shutter 18 is sequentially performed from the downstream side in the rotation direction of the drum 10. To perform each negative pressure generation chamber (16-1, 1
6-2, 16-3), the negative pressure generation can be performed sequentially from the downstream side to the upstream side.
It is possible to quickly and reliably hold the print medium M on the rotating drum 10 while preventing ink contamination of the print medium 1 and release the print medium M from the front end to the rear end of the print medium M after printing. Accordingly, by releasing the holding of the print medium M from the front end side to the rear side, smooth separation from the drum 10 can be performed. Further, even if the leading end of the print medium M is peeled off in a state where printing is being performed in the print head facing portion, the negative pressure after the head facing portion is established, so that printing is not affected.

Further, since the total opening area of each suction port 14 is larger than the total opening area of each suction hole 12, each suction hole 1
2, each negative pressure generating chamber (16-1, 16) of the drum 10
-2, 16-3), the amount of air flowing into each suction port 14
Through the respective negative pressure generating chambers (16-1, 16-) of the drum 10.
2, 16-3), the amount of air sucked out increases, so that each negative pressure generation chamber (16-
1, 16-2, 16-3).

Further, since the rubber roller (51) for squeezing the printing medium M, which is suction-held under negative pressure, is provided on the outer peripheral surface 11 of the drum with the rotation of the drum 10, the printing medium M may be loosened or the like. Even if negative pressure is attracted to the drum outer peripheral surface 11, the slack is extended by the rubber roller (51). Therefore, the print medium M can be adhered without wrinkles or the like.

Since the drum 10 (15R) and the negative pressure establishing means 31 (5R) are not in contact with each other, the drum 1
0 can be reduced and smooth rotation can be ensured. The gap between the two 15R and 5R is also useful for reducing the load fluctuation of the suction fan 32 when the print medium M is suctioned at the negative pressure and when it is not.

Since the holding means 41 is provided as an auxiliary means to hold the leading end of the print medium M, the print medium M can be held on the drum 10 more stably and reliably.

It should be noted that a charging means (not shown) may be provided as an auxiliary means in place of the holding means 41 or together with the holding means 41 so that the printing medium M is attracted to the drum 10.

[0054]

According to the first aspect of the present invention, a negative pressure generating chamber is formed by dividing the internal space of the drum into a plurality of parts, and a plurality of suction holes are formed in each negative pressure generating chamber so as to radially penetrate the inside and outside of the drum. In addition, a plurality of suction ports for communicating each negative pressure generation chamber with the outside and a shutter capable of opening and closing each suction port are provided on the end face side of the drum, and each shutter is provided on the stationary side using the rotation of the drum in the rotation direction. An opening / closing mechanism that can be opened and closed in order from the downstream side to the upstream side, and a suction fan that sucks air in the negative pressure generation chamber through an open suction port are used to utilize the negative pressure of each negative pressure generation chamber. The printing medium is formed on the outer peripheral surface of the drum so as to be capable of holding by suction under negative pressure, so that the outer peripheral surface of the drum is prevented from being stained with ink, and the printing medium is quickly and reliably held on the rotating drum and released after printing. be able to.

According to the second aspect of the present invention, since the total opening area of each suction port is equal to or larger than the total opening area of each suction hole,
The same effect as in the case of the invention of claim 1 can be obtained,
A negative pressure can be more reliably formed in the internal space of the drum.

Further, according to the third aspect of the present invention, since a rubber roller is provided on the outer peripheral surface of the drum as the recording medium is attracted and held by the negative pressure with the rotation of the drum, the rubber roller is provided. In addition to the same effect as in the case, the printing medium can be more reliably prevented from wrinkling and the like and can be held on the outer peripheral surface of the drum.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a view for explaining an internal structure of the drum.

FIG. 3 is a view for explaining a positional relationship between a drum and a suction fan.

FIG. 4 is a view for explaining a damper provided at a discharge port of the suction fan.

FIG. 5 is a view for explaining a holding claw holding means as an auxiliary means.

FIG. 6 is a view for explaining a clamping release operation of the clamping claw.

FIG. 7 is a diagram for explaining a previously proposed inkjet printer.

[Explanation of symbols]

 Reference Signs List 10 drum 11 drum outer peripheral surface 14 suction port 16 internal space 16-1 to 16-3 negative pressure generation chamber 18 shutter 25 opening / closing mechanism 32 suction fan 38 damper 51 charging roller (rubber roller)

Claims (3)

[Claims] 1. A medium holding device for an ink jet printer, which is held on a drum rotatable at a constant peripheral speed and is capable of printing while spraying ink from an ink jet nozzle onto a printing medium rotating with the drum. A plurality of negative pressure generation chambers are formed by partitioning the space in the radial direction, and a plurality of suction holes are formed in each of the negative pressure generation chambers so as to pass through the inside and outside of the drum in the radial direction. A plurality of suction ports that communicate the pressure generation chamber with the outside and a shutter that can open and close each suction port are provided, and each shutter is turned from the downstream side to the upstream side in the direction of rotation using the rotation of the drum on the stationary side. An opening / closing mechanism that can be sequentially opened and closed, and a suction fan that sucks air in the negative pressure generation chamber through an opened suction port, and uses the negative pressure of each negative pressure generation chamber to apply a print medium to the outer peripheral surface of the drum. Negative pressure suction was retainable form, medium holding apparatus of an ink jet printer, characterized in that. 2. The medium holding device for an ink jet printer according to claim 1, wherein a total opening area of each of the suction ports is equal to or larger than a total opening area of each of the suction holes. 3. A rubber roller which is capable of coming into contact with the outer peripheral surface of the drum and is provided with a rubber roller for squeezing the print medium from the front end to the rear end of the print medium which is suction-held on the outer peripheral surface of the drum with the rotation of the drum. 3. A medium holding device for an ink jet printer according to claim 1 or claim 2.