JPH10193582A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably print a drum rotating at high quality by forming a spray print part with ink to a print medium held on an outer periphery of the drum, and mounting rotary balance regulating weight at a non-printed area of the drum. SOLUTION: A rotary balance regulating weight 112 is suitably mounted on a non-printed area of a drum 10 to eliminate a rotary unbalance. The weight 112 is formed of a weight piece 112a detachably mounted by using a bolt 115 at an end face 15L of the drum 10 having a medium holding part (holding pawl 42) of a holding pawl holding means 41. And, the weight 112 can be mounted at the end 15L of the drum 10 before installing the holding part. And, the weight 112 can be mounted before or after the drum 10 is associated with a printer body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum provided rotatably in a fixed direction and a medium capable of holding a print medium on the outer peripheral surface of the drum by a medium holding portion and / or a negative pressure suction portion provided on the drum. And a holding unit.

[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 (printing 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.

Further, since the nozzle unit 200 for each color and the ink tank (not shown) for each color are arranged at a distance from each other, the nozzle unit 200 for each color can be lightened, and the reciprocating movement speed in the row direction can be further increased. The fact that the height can be increased further promotes a higher printing speed, and the capacity of the ink tank for each color can be greatly expanded, so that a continuous printing operation of, for example, 500 or more sheets can be performed.

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. A medium holding means 20 (negative pressure suction holding means 21, holding claws holding means 41, charging means 51, etc.) capable of holding the print medium M is provided on the drum 10 and its periphery.

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 unit 90 feeds the fed print medium M to the drum 10 at a predetermined timing after correcting the attitude of the print medium M with the supply rollers (91, 92).

The print medium M fed to the drum 10 side is
For example, the leading end is suctioned by the negative pressure suction portion (12) of the negative pressure suction holding means 21 on the drum outer peripheral surface 11 and is held by the medium holding portion (42) of the holding claw holding means 41, and is rearward. The portion is charged by the charging means 51.

In this manner, ink is sprayed from the ink jet nozzles 207 of the nozzle unit 200 for each color onto the print medium M sucked and held on the drum outer peripheral surface 11 to print characters and images.

The medium peeling means 140 peels the print medium M after printing from the drum 10 using the peeling claw 141, and the medium discharge / transport means 160 (the transport belt conveyor 161 and the pressing belt conveyor 165) prints the peeled print medium. M is conveyed to the left in FIG. The direction changing means 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 printing medium M can be continuously performed, multicolor printing of, for example, 20 sheets or more of A4 size can be performed in one minute.

[0012]

Incidentally, in order to increase the printing speed in the above-mentioned proposed inkjet printer, it is necessary to rotate the drum 10 stably at a high speed.
However, when the rotation of the drum 10 is accelerated, vibration or the like is generated, which may affect print quality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer capable of performing high quality printing by rotating a drum stably at a high speed.

[0014]

According to a first aspect of the present invention, there is provided a drum rotatably provided in a fixed direction, and a printing medium provided on the drum is provided with a medium holding portion and / or a negative pressure suction portion. And a printing unit capable of printing by spraying ink on the printing medium held on the outer peripheral surface of the drum, and a rotation balance adjusting weight is detachably mounted on a non-printing area of the drum. It is characterized by the following.

In this invention, the medium holding portion and / or the negative pressure suction portion are provided on the drum. The position of the medium holding portion and the like on the drum is limited to some extent due to the positional relationship with other components and the holding of the print medium. Therefore, when the drum is rotated (especially, when the drum is rotated at a high speed), rotational imbalance is likely to occur. However, the rotation imbalance can be eliminated by appropriately attaching the rotation balance adjusting weight to the non-printing area of the drum. Therefore, high quality printing can be performed by rotating the drum stably at high speed.

According to a second aspect of the present invention, the weight for adjusting the rotational balance is formed so that the weight can be increased or decreased.

In this invention, the rotational balance of the drum can be finely adjusted by increasing or decreasing the weight of the rotational balance adjusting weight. Therefore, the rotational imbalance can be more reliably eliminated.

[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. 6 to FIG. 6, the overall and basic structure is formed in the same manner as in the case of the previously proposed ink jet printer (FIG. 7). Is configured to be able to be eliminated.

The description of the same parts as those of the previously proposed ink jet printer will be simplified or omitted.

The drum 10 has a hollow cylindrical shape, and is capable of achieving multicolor printing of, for example, 20 PPM.
It is rotatable at 20 rpm. The print medium M sent from the medium supply unit 90 is held by the medium holding unit 20 on the outer peripheral surface 11 of the drum 10.

The medium holding means 20 includes a holding claw holding means 41 for holding the leading end side of the print medium M on the drum outer peripheral surface 11;
Negative pressure suction holding means 21 for holding the printing medium M on the drum outer peripheral surface 11 by using the negative pressure in the drum 10 and the suction holes 12 penetrating the drum 10 in the radial direction. I have. Further, in this embodiment, charge adsorption holding is introduced as auxiliary means.

The drum 10 is provided with a medium holding portion (such as a holding claw 42) of a holding claw holding means 41 in order to execute the holding of the printing medium M and the suction of the negative pressure.
A negative pressure suction unit (suction hole 12 and the like) is provided.

The positions of the medium holding section (42) and the negative pressure suction section (suction hole 12) are limited to some extent due to the positional relationship with other components, the holding of the print medium M, and the drum 10. Will be. Therefore, drum 1
When 0 is rotated (in particular, when rotated at high speed), rotational imbalance is likely to occur.

Therefore, in the present invention, the rotational imbalance is eliminated by appropriately mounting the rotational balance adjusting weight 112 in the non-printing area of the drum 10. More specifically, the weight 112 for rotational balance adjustment
As shown in FIG. 1A, a weight piece 112a removably mounted using a bolt 115 to an end surface 15L of a drum 10 provided with a medium holding portion (such as a holding claw 42) of a holding claw holding means 41, as shown in FIG. Is formed from. The female screw hole 1 that can be screwed with the bolt 115 is provided on the end face 15L of the drum 10.
16 are formed.

By appropriately adjusting the number of the weight pieces 112a, the weight of the rotation balance adjusting weight 112 can be increased or decreased. The weight piece 112a is formed by the cooperation of the bolt 115 and the female screw hole 116 with the medium holding portion (the holding claw 42).
Etc.) is installed in a position that does not interfere with the operation of

The weight 112 for adjusting the rotational balance is
As shown in FIG. 1B, the drum 10 can be mounted on the end face 15L of the drum 10 before the medium holding portion (such as the holding claw 42) is installed. The rotation balance adjusting weight 112 can be mounted either before or after the drum 10 is mounted on the printer main body 1.

With this configuration, the rotational imbalance of the drum 10 is eliminated by the rotational balance adjusting weight 112, so that the drum 10 can be smoothly and reliably rotated at a constant speed.

The negative pressure suction holding means 21, the holding claw holding means 41 and the charging means 51 will be described in detail below.

The negative pressure suction holding means 21 is shown in FIG.
4 (B) and FIG. 4, a negative pressure suction unit [a plurality of negative pressure generating chambers (16-1, 16-2, 16-
3), a suction hole 12, a suction port 14, a shutter 18], and an opening / closing mechanism 25 and a suction fan 32 on the stationary side.
The shutters 18 are sequentially opened from the downstream side in the rotation direction (Y) of the drum 10 so as to open the respective shutters 18 in the respective negative pressure generation chambers (1).
6-1, 16-2, and 16-3), the negative pressure generation can be sequentially performed in the reverse order of the rotation direction (Y).

As shown in FIG. 3A, the inner space 16 of the drum 10 has a partition wall (17-1, 17) extending radially.
−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 in 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. further,
As shown in FIG. 4, a plurality of suction ports 14 are provided on the end surface (side end plate 15 </ b> R) of the drum 10 to communicate each negative pressure generation chamber (16-1, 16-2, 16-3) with the outside. Have been.

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 the 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.

The shutter 18 is provided on the end face (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 / 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.

Accordingly, when the actuator 27A is driven to project the operating pin 27AP toward the drum end surface (15R) via the driving lever 27L, the collision portion 18K1 of the shutter 18 which rotates together with the drum 10 hits the operating 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. 3A, the engaging portion 18K2 of the shutter 18 engages with the lock lever 28L,
The engagement with the operation pin 27AP is released. This allows
The shutter 18 is locked in an open state.

When the actuator 29A is driven to project the operation pin 29AP toward the drum end face (15R) via the drive lever 29L, the lock lever 28L that rotates together with the drum 10 comes into contact with the operation 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 shaft of the drum 10. Further, as shown in FIGS. 5A and 5B, the holding claw holding means 41 includes a medium holding portion (holding claw 4).
2. One end (15L) of the drum 10 that includes a constant holding mechanism 43, a normally open lock mechanism 44), a lock release mechanism 45, and a lock return mechanism 46, and is a movable side of the medium holding section (42, 43, 44). Side and unlock mechanism 4
5 and the lock return mechanism 46 are the main body case 1 on the stationary side.
It is configured to be attached to a bracket (not shown) in the inside. The lock release mechanism 45 and the lock return mechanism 46 engage with the constant holding mechanism 43 and the constant release lock mechanism 44 while performing the rotation of the drum 10 to clamp and release the clamping claw 42. It is formed.

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 constant holding mechanism 43 includes a lever 43L (a base end 43B, a distal end 43B) rotatable around 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. Utilizing the pulling force), the holding claw 42 is always kept in the holding state shown by the two-dot chain line in FIG.

The normally-release lock mechanism 44 comprises a lock lever 44L that can rotate about a pin 44P. An engagement groove 44C of the lock lever 44L is formed so as to be able to engage and disengage with an engagement portion 42C of the holding claw 42. And both 44C and 42C
5A, the holding claws 42 can be always locked in the holding and releasing state shown by the solid line in FIG. 5A.

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 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.

In this embodiment, however, the drum 10
The weight 112 for rotation balance adjustment is detachably mounted on the non-printing area (end face 15L) of the medium.
43, 44) and the negative pressure suction section (12, 14, 18), the drum 10 can be rotated without any rotational imbalance. Therefore, high quality printing can be performed by rotating the drum 10 stably at high speed.

Further, since the rotation balance adjusting weight 112 is formed so that the weight can be increased or decreased, the rotation balance of the drum 10 can be finely adjusted. Therefore, the rotational imbalance can be more reliably eliminated.

The rotation balance adjusting weight 112 is
Since the drum 10 can be attached to the drum 10 before or after assembling to the printer main body 1, handling is more convenient.

[0049]

According to the first aspect of the present invention, since the rotation balance adjusting weight is removably mounted in the non-printing area of the drum, the drum can be rotated at a high speed stably for high quality printing.

According to the second aspect of the present invention, since the weight of the rotation adjusting weight can be increased or decreased, the drum can be rotated with higher precision to perform high quality printing.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining the overall configuration.

FIG. 3 is a view for explaining a negative pressure suction holding means.

FIG. 4 is a side sectional view for explaining a negative pressure suction operation.

FIG. 5 is also a view for explaining a holding claw holding 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]

 DESCRIPTION OF SYMBOLS 10 Drum 11 Drum outer peripheral surface 20 Medium holding means 21 Negative pressure suction holding means 16-1 to 16-3 Negative pressure generation chamber (negative pressure suction part) 12 Suction hole (negative pressure suction part) 14 Suction port (negative pressure suction part) 18 Shutter (negative pressure suction unit) 41 Holding claws holding means 42 Holding claws (medium holding unit) 43 Always holding mechanism (medium holding unit) 44 Always open lock mechanism (medium holding unit) 112 Weight for rotation balance adjustment 112a Weight piece

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitoshi Shioki 6-78, Minamicho, Mishima-shi, Shizuoka Prefecture Inside the Technical Research Institute Co., Ltd. (72) Inventor Yasuhiro Suzuki 6-78, Minamicho, Mishima-shi, Shizuoka Prefecture In-house

Claims (2)

[Claims] 1. A drum rotatably provided in a fixed direction, a medium holding means provided on the drum and capable of holding a printing medium on a drum outer peripheral surface by a medium holding portion and / or a negative pressure suction portion, and a drum outer periphery An ink jet printer comprising: a printing unit that can print by spraying ink on a printing medium held on a surface; and a rotation balance adjustment weight detachably mounted on a non-printing area of the drum. 2. The ink jet printer according to claim 1, wherein the weight for adjusting the rotational balance is formed so as to be able to increase and decrease the weight.