JPH10175342A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retain a printing medium on a rotating drum quickly and securely by forming a plurality of negative pressure forming chambers in an inner space of the drum by partition walls extending in the radial direction and opening and closing a plurality of suction holes communicating the respective pressure forming chambers with outside by shutters interlocked with the rotation of the drum. SOLUTION: A plurality of negative pressure forming chambers 16 (16-1-16-4) formed by partition walls 17-1-17-4 are provided in a drum 10, and suction holes 12 are formed on a drum outer peripheral face 11 and suction holes 14 opened and closed by shutters 18 are formed in respective negative pressure forming chambers 16 on the drum end face. Suction fans are provided on the stationary side, and the opening of respective shutters 18 is carried out starting from the downstream side of the rotating direction of the drum 10 by an opening mechanism 27 of an opening and closing mechanism 25 successively. Then the end of a printing medium M negative pressure sucked through the suction holes 12 communicated with the negative pressure forming chambers 10 negative pressure formed successively is retained on the drum outer peripheral face 11 by using a clamping pawl to carry out the printing by an 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 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.

[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. 6, 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. It is necessary to be able to hold it securely.

Further, in order 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 ink jet nozzle 207.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer which can hold a printing medium quickly and reliably on a rotating drum while preventing the outer peripheral surface of the drum from being stained with ink.

[0011]

According to 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 negative pressure generation chamber divided into a plurality of sections by a partition extending radially in the internal space of the drum, and a plurality of suction holes radially penetrating the inside and outside of the drum in each negative pressure generation chamber; 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 in the rotation direction by using the rotation of the drum. An opening / closing mechanism that can be sequentially opened and closed from a downstream side to an upstream side, and a suction fan that sucks air in the negative pressure generation chamber through an open suction port are provided, and a negative pressure in each negative pressure generation chamber is used. Printing And a clamping claw holding means for pressing and holding the peripheral portion of the printing medium held by the negative pressure suction on the outer peripheral surface of the drum using a clamping claw. It is characterized by the following.

In the case of this invention, when the opening and closing mechanism is operated in accordance with the print 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 through the opposed suction holes in the rearward portion 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, in each of the negative pressure generating chambers, a negative pressure is established in a state where the corresponding suction holes are covered with the print medium, so that ink is discharged from, for example, the discharge port of the ink jet nozzle through the suction holes. There is no such thing as inhaling,
It is possible to prevent the outer peripheral surface of the drum from being soiled. Since the peripheral portion (for example, the front end portion) of the print medium is held by the holding claws in accordance with the negative pressure suction holding, the print medium can be more securely held on the outer peripheral surface of the drum.

According to a second aspect of the present invention, an operating member for performing the holding operation and the holding and releasing operation of the holding claw is provided inside the outer peripheral surface of the drum without entering the internal space of the drum. It is characterized by.

In the case of this invention, it is not necessary to form an opening in the drum for allowing a part of the operating member to enter the internal space of the drum. Pressure can be generated. Further, since the operation member is located inside the outer peripheral surface of the drum, the print medium can be reliably held on the outer peripheral surface of the drum without obstructing the suction of the print medium through each suction hole.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. This inkjet printer is shown in FIG.
As shown in FIG. 5, 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 opened 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). Further, the holding claw holding means 41
The peripheral portion (for example, the front end portion) of the print medium M held by the negative pressure suction is held by using
Is held by pressing.

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. 3, 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.

Further, the holding claw holding means 41 includes a holding claw 4.
2, including a constantly-clamping mechanism 43, a normally-open lock mechanism 44, a lock-release mechanism 45, and a lock-return mechanism 46;
Is attached to one end (15L) of the drum 10 which is a movable side, and a lock release mechanism 45 and a lock return mechanism 46
Is mounted on a bracket (5L) in the main body case 1 which is a stationary side. Then, the lock release mechanism 45
The lock return mechanism 46 is configured to perform the clamping and the clamping release of the clamping claw 42 in cooperation with the constant clamping mechanism 43 and the constant release locking mechanism 44 while skillfully utilizing the rotational movement of the drum 10.

The holding claw 42 and the operating members (in this embodiment, the always holding mechanism 43 and the always-open lock mechanism 44) for holding the holding claw 42 do not enter the drum internal space 16. And is provided inside the outer peripheral surface 11 of the drum 11. Thereby, the holding claws 4
There is no occurrence of a situation where 2 becomes an obstacle for negative pressure suction holding.

Hereinafter, each component of the holding claw holding means 41 will be described in detail. The holding claws 42 are formed so as to be able to hold the printing medium M on the outer peripheral surface 11 of the drum 10. Specifically, as shown in FIGS. 4A and 4B,
It has a claw 42F, an engaging portion 42C, and a sector gear 42G, and is attached rotatably about a pin 42P. The peripheral portion (for example, the leading end portion) of the print medium M is sandwiched between the drum outer peripheral surfaces 11 by the claws 42F.

The constant holding 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. 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
By the engagement of C, the holding claw 42 is formed so as to be always lockable in the holding release state shown by the solid line in FIG.

The lock release mechanism 45 includes a pin 45 on the stationary side.
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. 5A, the lock return mechanism 46 includes a lever 46L (a distal end 46F and a proximal end 46B) that can rotate around 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.

A portion of the printing medium M on the rear side from the leading end side also has a negative pressure in each of the negative pressure generating chambers (16-2, 16-3) on the upstream side in the rotation direction sequentially through the opposed suction holes 12. 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 the time of the negative pressure suction, the leading end of the print medium M is held by the holding claws 42 of the holding claw holding means 41.
Will be held.

Here, the holding claws 42 and the operating members (the always holding mechanism 43 and the always open lock mechanism 44)
Since it is provided not inside the drum internal space 16 but inside the drum outer peripheral surface 11, a negative pressure is reliably generated in the drum internal space 16, and the print medium M is formed through the suction holes 12.
Can be stably sucked at a negative pressure, and a situation in which the holding claws 42 and the like collide with a component (for example, the inkjet nozzle (207)) arranged close to the drum outer peripheral surface 11 does not occur.

In this manner, 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) so that the negative pressure can be generated sequentially from the downstream side to the upstream side, and the peripheral portion (tip portion) of the printing medium M held by the negative pressure is held by the holding claws. And the holding claw holding means 41 for pressing and holding the outer peripheral surface 11 of the drum 10 using the outer peripheral surface 42. Thus, the drum which rotates the print medium M quickly and reliably while preventing the drum outer peripheral surface 11 from being stained with ink. 10 and print medium M after printing
Can be sequentially released from the front end side to the rear end side. 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. In addition, since the negative pressure suction is performed while the leading end of the print medium M is held by the holding claws, the print medium M can be more reliably held on the drum outer peripheral surface 11.

An operating member for holding and holding the holding claw 42 is provided in the internal space 1 of the drum 10.
6 is provided inside the outer peripheral surface 11 of the drum 10 so that a negative pressure can be reliably generated in the internal space 16 and the print medium M can be reliably provided without hindering the suction of the negative pressure. Can be held on the drum outer peripheral surface 11.

Further, since the leading end of the print medium M is mechanically held between the drum outer peripheral surface 11 by the holding claws 42, even if the leading end side of the print medium M is turned up, it is securely held and a jam occurs. Can be prevented.

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 print medium M held by the negative pressure suction on the drum outer peripheral surface 11 with the rotation of the drum 10 is provided, the print 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.

Further, since the drum 10 (15R) is not in contact with the negative pressure establishing means 31 (5R), 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 to make the drum 10 charge-adsorb the printing medium M.

[0058]

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, the operating member for performing the holding operation and the holding release operation of the holding claw is provided not inside the internal space of the drum but inside the outer peripheral surface of the drum. In addition to the same effect as that of the first aspect, the negative pressure can be reliably generated in the internal space, and the print medium can be reliably held on the outer peripheral surface of the drum without obstructing negative pressure suction.

[Brief description of the drawings]

FIG. 1 is a diagram for describing 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 damper.

FIG. 4 is a view for explaining a holding claw holding means.

FIG. 5 is a view for explaining a clamping release operation of the clamping claw.

FIG. 6 is a diagram for explaining a previously proposed inkjet printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 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 41 Nipping claw holding means 42 Nipping claw

Claims (2)

[Claims] 1. An ink jet printer which is held by 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, wherein the inner space of the drum is formed in a radial direction. A plurality of negative pressure generation chambers are formed by partition walls extending into the negative pressure generation chambers, and a plurality of suction holes are formed in each of the negative pressure generation chambers so as to radially penetrate the inside and outside of the drum. Equipped with a plurality of suction ports communicating with the outside and a shutter that can open and close each suction port, each shutter is sequentially opened and closed from the downstream side to the upstream side in the rotation direction using the rotation of the drum on the stationary side A possible opening / closing mechanism and a suction fan that sucks air in the negative pressure generating chamber through an opened suction port are provided, and the negative pressure of each negative pressure generating chamber is used to hold the print medium on the outer peripheral surface of the drum by negative pressure. An ink-jet printer which together form the ability peripheral portion of the negative pressure suction retained print medium formed from a clamping claw holding means for pressing and holding the outer peripheral surface of the drum with a clamping claw, characterized in that. 2. An operation member for performing a clamping operation and a clamping release operation of the clamping claw is provided not to enter the internal space of the drum and inside the outer peripheral surface of the drum.
The ink jet printer according to claim 1, wherein: