JPH10175292A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve miniaturization and cost reduction and to increase a wiping frequency by providing a wiping member intermittently coming into contact with ink jet nozzles accompanying the rotation of a drum to remove ink bonded to emitting orifices to the outer peripheral surface of the drum. SOLUTION: Respective nozzle units 200C, 200M, 200Y, 200B are arranged to the periphery of a drum 10 and have a large number of ink jet nozzles 207 arranged in a line X0 direction at a constant pitch. A wiping means 20 consisting of a wiping member 22 and a holding member 21 for holding the wiping member to the outer peripheral surface of the drum is mounted to the drum 10. The holding member 21 comes into contact with the inner peripheral surface 12 of the drum and a plurality of blades 23 forming the wiping member 22 protrude outward through through-holes 13. This mounting range θ is set to a position shifted from the holding region La of the printing medium. The respective blades 23 are arranged to the outer peripheral surface 11 in a separated state and formed from silicone rubber rich in elasticity.

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 capable of high-speed printing by discharging ink from an ink jet nozzle disposed around a drum on a print medium held on the outer peripheral surface of a rotatable 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 which feeds M by one line in the column direction and repeats them, printing speed can be drastically increased and continuous printing operation can be performed over a large number of sheets. The present applicant has proposed an ink jet printer capable of achieving a large size reduction (for example, Japanese Patent Application No. 8-296957).

That is, in FIG. 7, a drum 10 is rotatable at a constant peripheral speed about an axis X0 and can hold a print medium M on an outer peripheral surface 11 thereof. A nozzle unit 200 for each color (C, M, Y, B) is arranged in the rotation (Y) direction of the drum 10. Therefore, an integrated nozzle unit 200 for each color in the entire length in the row direction (perpendicular to the paper surface) 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, ink is ejected from the ink jet nozzles 207 for each color on the rotating print medium M while reciprocating by the pitch between the ink jet nozzles to print in the row direction, and the rotation of the drum 10 is used during the forward movement of the ink jet nozzle pitch. While printing in the column direction. That is, since the line-direction printing and the column-direction printing can proceed simultaneously, the printing speed can be greatly increased.

[0004] Further, since the nozzle unit 200 for each color and the ink tank (ink cassette) 213 for each color are arranged at a distance from each other, 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, a medium feeding means 60 and a medium feeding means 90 are provided on one side (right side in FIG. 7) of the drum 10, and a medium is provided on the other side (left side in FIG. 7). Peeling means 140, medium discharging / conveying means 160, and direction switching means 1
90 are provided.

The medium feeding means 60 includes a cassette feeding means 7
The print medium M can be selectively fed one sheet at a time from either one of the manual feeding means 61 and the manual feeding means 61. Medium supply means 90
Supplies the fed print medium M to the drum 10 at a predetermined timing. The medium peeling means 140 peels the print medium M from the drum 10 after printing, and the medium discharge / transport means 160 discharges and transports the peeled print medium M leftward 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]

Incidentally, since the previously proposed printer is also of the ink jet type, it is necessary to remove the ink adhering to the ejection holes of each ink jet nozzle 207 and the vicinity thereof. This is so-called wiping.
Generally, it is desirable to perform as many wiping operations as possible in a short time in order to maintain high quality printing.

However, each color ink jet nozzle 20
In the unique configuration in which the drum 7 is displaced in the rotation direction of the drum 10 and faces the rotating drum outer peripheral surface 11 with a gap of, for example, 0.5 to 1 mm, there are the following study subjects.

That is, in FIG. 7, the entire nozzle unit 200 for each color is retreated to the left in the figure so as to be away from the drum 10 (11), so that a large space is formed between the drum outer peripheral surface 11 and each ink jet nozzle 207. The wiping is performed by moving the wiping unit from the lower side or the direction of the axis X0 into this space. Thereafter, the nozzle unit 200 is reversely operated to move the entire nozzle unit 200 to the drum 10 (1).
It is conceivable to construct the vehicle so that it is moved rightward and approached in 1).

However, in a system in which the nozzle unit 200 and the wiping unit are entirely moved by using special means or dedicated power, the mechanism becomes complicated and large, and the whole printer becomes large and costly. Furthermore, since it takes a long time to prepare and restore for wiping, not only can the number of wiping operations within a certain time not be increased,
This will hinder high-speed printing.

An object of the present invention is to provide an ink jet printer which can increase the number of times of wiping without hindering high-speed printing while reducing the size and cost.

[0013]

The technical principle and basis of the printer proposed in the prior art is to perform line direction printing while reciprocating the nozzle unit by, for example, 1/75 inch in the line direction parallel to the drum axis. The printing speed can be increased by simultaneously performing the column direction printing using the rotational movement of the drum.

Here, the present invention refocuses attention on the rotational movement of the drum, and is configured such that a wiping member can be mounted on the drum side and wiping can be performed using the rotation of the drum.

In other words, according to the first aspect of the present invention, ink is ejected from an ink jet nozzle disposed around the drum onto a print medium held on the outer peripheral surface of the drum rotatable about an axis so that printing is possible. In addition, a wiping member is provided on the outer peripheral surface of the drum so as to intermittently contact the ink jet nozzle with the rotation of the drum and remove the ink attached to the ejection hole of the ink jet nozzle.

In this invention, when the drum is rotated,
While the print medium is being held on the outer peripheral surface of the drum, during a subsequent printing operation, and even after the print medium has been separated from the outer peripheral surface of the drum after printing, the wiping member provided on the outer peripheral surface of the drum causes each ink jet to rotate as the drum rotates. Winding is performed while repeatedly and intermittently contacting the discharge holes of the nozzles. Therefore, high quality printing can always be maintained.

The invention according to claim 2 is an ink jet printer, wherein the wiping member is formed of a plurality of blades extending in the axial direction and spaced apart in the circumferential direction on the outer peripheral surface of the drum.

In this invention, the blade at the most upstream side in the drum rotation direction performs wiping. Since the blade extends in the axial direction, each ink jet nozzle can be wiped at a time. Subsequently, the next blade on the downstream side in the rotation direction that has moved with the rotation of the drum is wiped. During one rotation of the drum, wiping can be performed intermittently by the same number of times as the number of blades spaced apart in the circumferential direction. Therefore, the same operation and effect as those of the first aspect of the present invention can be obtained, and even if the ink remains in the first wiping, the ink is removed in the second and subsequent times, so that the wiping effect can be more surely enhanced. The selectivity of blade material, rigidity, etc. can be expanded.

The invention according to claim 3 is an ink jet printer in which the wiping member is formed of a plurality of blades arranged on the outer peripheral surface of the drum in the circumferential direction and the axial direction.

According to this invention, the first blade in the circumferential direction, which is spaced apart in the axial direction and wipes, is wiped. Next, the next blade moved with the rotation of the drum performs wiping. By arranging the first blade and the next blade so that their ends are adjacent to each other in the axial direction or part of them are overlapped, it is possible to sequentially wipe the ink jet nozzles in the axial direction and without falling off. it can. Therefore, the same operation and effect as those of the first aspect of the invention can be obtained, and the contact state between each blade and the ejection hole of each ink jet nozzle can be made more uniform, so that the wiping effect can be further improved.

Further, the invention according to claim 4 is an ink jet printer in which each blade on the upstream side and each blade on the downstream side in the drum rotation direction in the circumferential direction of the drum are displaced in the axial direction. .

In this invention, after the blades on the upstream side wipe, the blades on the downstream side that are displaced in the axial direction wipe the nozzle discharge holes that have not been wiped on the upstream side. Therefore, in addition to having the same operation and effect as the case of the third aspect of the present invention, each blade can be formed to be small and capable of soft touch, and each discharge hole can be wiped in a plurality of times in the axial direction and circumferential direction. More reliable ink removal can be performed.

Further, the invention according to claim 5 is an ink jet printer wherein each of the blades is inclined in the axial direction and the circumferential direction.

According to this invention, each blade wipes while sequentially contacting the nozzle discharge holes arranged in the axial direction. Therefore, the same operation and effect as those of the inventions of claims 2 to 4 can be obtained, and further, all the nozzle ejection holes can be wiped while discharging the removed ink in one direction in the axial direction. It is possible to more reliably prevent the ink from re-adhering to the ejection holes or the like.

Further, the invention according to claim 6 is an ink jet printer wherein each of the blades is mounted on the drum so as to be able to protrude and retract in a radial direction of the drum.

In this invention, each blade is projected in the radial direction of the drum when wiping is used, and is buried inside the outer peripheral surface of the drum when not used. Therefore, claim 2
In addition to the effects similar to those of the inventions according to the fifth to fifth aspects, the selectivity of the mounting position of the wiping member with respect to the drum can be greatly expanded, and the entire area of the outer peripheral surface of the drum is effective for holding the print medium and the like. Available and free from interference with other components arranged around the drum.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG.
As shown in FIG. 5, the ink is ejected from an ink jet nozzle 207 disposed around the drum onto a print medium M held on the outer peripheral surface 11 of the drum 10 rotatable about the axis X0, and the drum is formed so as to be printable. 10 intermittently contacts the inkjet nozzle 207 with the rotation of the drum 10 on the outer peripheral surface 11 of the inkjet nozzle 2.
A wiping member 22 for removing the ink attached to the discharge holes 07 is provided, and the wiping of each ink jet nozzle 207 can be executed by using the rotation of the drum 10.

A description will be given of a case where the overall basic configuration is the same as that of the previously proposed printer (FIG. 7). However, description of portions common to the case of FIG. 7 is simplified or omitted.

In FIG. 1, a drum 10 is rotatable in the Y direction about an axis X0, and its outer peripheral surface 11 can hold a print medium M in cooperation with a medium holding means (not shown). .

The drum has a diameter of 130 mm and has an outer peripheral length (408 mm) capable of holding A4 size (length La: 297 mm) with a margin. The rotation speed is 20
120 rpm that can achieve color printing of ppm
The drum 10 makes one rotation in 0.5 seconds.

Around the drum 10, nozzle units 200C, 200M, 200Y and 200B for the respective colors are displaced in the rotation (Y) direction. Each nozzle unit 200 has a constant pitch (for example, in the row (X0) direction).
Many (eg, 636) arranged in 1/75 inch
) Inkjet nozzles 207.

The wiping means 2 includes a wiping member 22 and a holding member 21 for holding the wiping member 22 on the outer peripheral surface 11 of the drum.
0 is attached.

The holding member 21 is in contact with the drum inner peripheral surface 12 and forms a plurality of wiping members 22 (for example, 5
) Are protruded and held outward through the through holes 13. The mounting range θ is determined by the holding area (L
This is a position outside a).

Each blade 23 is spaced apart in the circumferential direction on the outer peripheral surface 11 and extends in the direction of the axis X0 and has a thin plate shape in the Y direction, and is made of a highly elastic material (for example, silicon rubber, felt, Sponge etc.).

Thus, when the drum 10 is rotated in the Y direction, each blade 23 is
The ink adhering to the discharge hole 07 (not shown) and its periphery can be removed.

Moreover, since the blades 23 are spaced from each other in the circumferential direction of the drum 10, even if a small amount of semi-dry ink remains, for example, due to the wiping of the blade 23 on the downstream side (coming ahead) in the rotational direction. Since the blades 23 on the upstream side (later) wipe one after another, the ink can be completely removed.

In FIG. 1, the protrusion length of each blade 23 is shown longer for convenience of explanation, but the actual protrusion length is each ink jet nozzle 207 and the outer peripheral surface 11 of the drum.
(For example, 1 mm). On the other hand, since the dimension from the drum outer peripheral surface 11 to the inner peripheral surface 12 is long, for example, 3.5 mm, and the holding member 21 is made of the same material as the material of each blade 23, the removed ink is reliably absorbed. can do.

Further, each ink jet nozzle 207
Can be sequentially wiped by the five blades 23 that intermittently contact each rotation of the drum (0.5 second), so that the number of times of wiping can be greatly increased.

In this way, since each ink jet nozzle 207 can be wiped before printing on the printing medium M and can be wiped immediately after printing even during the printing operation, high quality printing can be maintained even in the continuous operation of a large number of sheets (for example, 500 sheets). it can.

Further, since there is no need for a mechanism for moving the nozzle unit 200 for each color toward and away from the drum 10 and for moving the wiping means 20, a great reduction in cost and size can be achieved. Since the rotation of the drum is used, there is no need for special power for causing the wiping member 22 to reciprocate, for example, in an arc.

Further, since the wiping member 22 is formed by a plurality of blades 23 which are spaced apart in the circumferential direction,
The selectivity such as the material and rigidity of each blade 23 can be expanded.
That is, the blade 23 with respect to the nozzle head (200)
, The thickness and rigidity of each blade 22 can be reduced. Moreover, since a plurality of sheets are provided, the cleaning effect is not reduced. Therefore, the life of the nozzle head (200) can be extended.

(Second Embodiment) This embodiment is shown in FIGS. That is, each blade 23 is mounted on the drum 10 so as to be able to protrude and retract in the drum radial direction.

Each blade 23 is the same as that of the first embodiment, but the holding member 21 is
2 is urged rightward in FIG. 2 by a spring 39 mounted therein. That is, the tip of each blade 23 is accommodated in the through hole 13 so as not to protrude outward from the drum outer peripheral surface 11. Position regulation for this is performed by a guide member 14 having a position regulation portion 15 fixed to the drum inner peripheral surface 12.

The wiping driving means 30 is formed of a link mechanism (31, 32), a solenoid 35, and a spring 37, and is formed so that each blade 23 can be protruded by the time of wiping use and can be immersed after wiping. In addition,
The link mechanisms (32, 33) are provided as a pair on both ends of the support shaft 31 rotatably held as shown in FIG.

That is, the one link bar 32 and the other link bar 33 are integrally formed and can be synchronously rotated around the support shaft 31 in the same direction. The spring 37 is capable of constantly biasing the other link bar 33, while biasing the link bar 32 in a direction away from the holding member 21 as shown by a two-dot chain line in FIG.

As shown by a solid line in FIG. 2, the solenoid 35 is provided with a holding member as shown by a solid line in FIG. 2 through a pin 36 slidably fitted in the long hole 34 of the other link bar 33 and against the urging force of the spring 37. 21 can be moved to the left in FIG. 1 against the urging force of the spring 39.

Thus, by driving the wiping driving means 30 in association with the rotational movement of the drum 10, the wiping member 22 (each blade 23) can protrude so as to be able to contact each ink jet nozzle 207 as shown in FIG. By doing so, it can be stored inside the outer peripheral surface 11.

The driving power of the wiping driving means 30 (solenoid 35) is supplied through a hollow shaft (not shown) including the axis X0. A slide contact terminal ring may be provided and supplied from the stationary side via the slide contact terminal ring. Further, the drum 10 may be formed to work mechanically from the stationary side by utilizing the rotational movement itself of the drum 10.

Therefore, according to the second embodiment, the same operation and effect as in the first embodiment can be obtained, and further, the selectivity of the mounting position of the wiping member 22 with respect to the drum 10 (outer peripheral surface 11). And the entire area of the outer peripheral surface of the drum can be effectively used for holding the print medium M, and there is no fear of interference with other components (for example, a charging roller) disposed around the drum.

(Third Embodiment) As shown in FIG. 4, each blade 23 is integrally extended in the direction of the axis X0 in the first embodiment.
And are spaced apart in the circumferential (Y) direction and the axis X0 direction.

That is, each blade 23A, 23B, 2
3C and 23D are connected to the row of the inkjet nozzle 207 (X
The length in the 0) direction is slightly larger than the length divided in four, is displaced in the Y direction, and is formed on the holding member 21 such that both ends thereof overlap with the adjacent blades 23 in the direction of the axis X0. I have.

Although the holding member 21 is rectangular for simplicity of illustration, it is actually arc-shaped in contact with the inner peripheral surface 12 as in the first embodiment.

Thus, with the rotation of the drum 10, the first blade 23A on the downstream side in the Y direction wipes a part (1/4) of the ink jet nozzle (ejection hole) 207 for each color, and the blades 23B, 23C, and 23D continue. Each part (1/4 each) is sequentially wiped. Each of the blades 23A to 23D adjacent in the direction of the axis X0 partially overlaps in the direction of the axis X0.
Wiping of all the nozzles can be surely performed.

Therefore, according to the third embodiment, each of the nozzles 207 is wiped all at once by the integral blade 23 in the direction of the axis X0 as in the first and second embodiments. Since the contact state between the blades 23 and the corresponding nozzle discharge holes can be made more uniform, the wiping effect can be further improved.

Also, since each blade is small, the nozzle 20
The selectivity such as dimensions, material, rigidity, etc., required to make the state of contact with 7 uniform can be greatly increased as compared with the case of the first embodiment.

(Fourth Embodiment) In FIG. 5, the blades 23 on the upstream side and the blades 23 on the downstream side in the drum rotation (Y) direction in the circumferential direction of the drum 10 are connected to each other by an axis X0.
This is the case where they are displaced in the direction.

That is, as compared with the third embodiment, each of the blades 23 is further subdivided, and the ink jet nozzle 207 which is not wiped by the downstream blade (for example, 23C1) is adjacent to the downstream blade (23C1). It is formed so as to be complemented by the upstream blades (23B2, 23C2), complemented by the blade (23C3), and finally complemented by the blades (23B4, 23C4).

That is, even if ink flows on both sides when wiping with a certain blade (23C),
This can be reliably removed by the next blade (23B2, 23C2), and at the same time, the contact between each blade 23 and each corresponding nozzle 207 is enhanced, and the contact between all the blades 23 and all the nozzles is made more uniform. It is.

According to the fourth embodiment,
Compared with the third embodiment, each blade 23 can be formed to be smaller and soft-touchable, and the ink can be more reliably removed by wiping each ejection hole a plurality of times.

(Fifth Embodiment) In FIG. 6, each blade 23 is provided to be inclined in the direction of the axis X0 and in the circumferential (Y) direction.

That is, the first blade 23A is similarly disposed to the lower left in FIG. 6, and the next blade 23B is similarly disposed to the lower left so that the right end thereof overlaps the left end of the blade 23A in the direction of the axis X0. Other blades 23C, 23
D is the same.

Therefore, each blade 23D, 23C,
The left ends of 23B and 23A first come into contact with the corresponding nozzles 207, and sequentially come to the right in FIG. In other words, the ink to be removed is moved in one (right) direction of the drum axis X0, so that ink re-scattering and re-adhesion to the nozzle (ejection hole) 207 can be prevented.

Further, if the number and rigidity of each blade 23 are appropriately selected, the ink splash when the blade 23 is separated from the nozzle head (200) can be further reduced.

If the present invention is applied to the blades 23 shown in FIGS. 1, 2, 4, and 5, more reliable wiping can be performed.

[0065]

According to the first aspect of the present invention, it is possible to perform printing by ejecting ink from an ink jet nozzle arranged around the drum onto a printing medium held on the outer peripheral surface of the drum rotatable about the axis. A wiping member is provided on the outer peripheral surface of the drum, which intermittently contacts the ink jet nozzle with the rotation of the drum and removes the ink attached to the discharge hole of the ink jet nozzle, and discharges using the rotation of the drum. Since the hole is formed so as to wipe, there is no need for a large-scale wiping means or a special moving mechanism for the nozzle unit. Therefore, the size and cost can be greatly reduced, and the number of times of wiping can be greatly increased. High quality printing can be maintained.

According to the second aspect of the present invention, the wiping member is formed of a plurality of blades extending in the axial direction and spaced apart in the circumferential direction on the outer peripheral surface of the drum. In addition to providing the same effects as those of the invention, the remaining wiping is removed in the second and subsequent times, so that the wiping effect can be further enhanced and the selectivity of each blade, such as material and rigidity, can be expanded.

According to the third aspect of the present invention, the wiping member is formed of a plurality of blades which are spaced apart in the circumferential direction and the axial direction on the outer peripheral surface of the drum. In addition to having the same effect as the case,
Furthermore, since the contact state between each blade and the corresponding nozzle discharge hole can be made more uniform, the wiping effect can be further improved.

Further, according to the present invention, the blades on the upstream side and the blades on the downstream side in the drum rotation direction in the circumferential direction of the drum are displaced in the axial direction. In addition to achieving the same effects as in the invention of the third aspect, each blade can be formed small and capable of soft touch, and each ejection hole can be wiped in the axial direction and the circumferential direction a plurality of times, so that a more reliable ink can be obtained. Can be removed.

Further, according to the fifth aspect of the present invention, since each blade is inclined in the axial direction and the circumferential direction, the same effects as in the second to fourth aspects of the invention can be obtained. In addition to this, since all the nozzle ejection holes can be wiped while discharging the removed ink in one direction in the axial direction, it is possible to more reliably prevent the ink once removed from re-adhering to the ejection holes and the like.

Furthermore, according to the invention of claim 6, since each blade is mounted on the drum so as to be able to protrude and retract in the radial direction of the drum, the same effect as in the inventions of claims 2 to 5 is obtained. In addition to the above, it is possible to greatly increase the selectivity of the mounting position of the wiping member with respect to the drum, and to effectively use the entire outer peripheral surface of the drum for holding a print medium and to arrange other components disposed around the drum. No worries about interference.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a side view showing a second embodiment.

FIG. 3 is a plan view showing a second embodiment.

FIG. 4 is an external perspective view showing the third embodiment.

FIG. 5 is an external perspective view showing the fourth embodiment.

FIG. 6 is an external perspective view showing a fifth embodiment.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Drum 11 Outer peripheral surface 12 Inner peripheral surface 13 Through-hole 14 Guide member 15 Position regulation part 20 Wiping means 21 Holding member 22 Wiping member 23 Blade 25 Hollow part 30 Wiping drive means 31 Support shaft 32 One link bar 33 Other link bar 35 Solenoid 37 spring 39 spring 200 nozzle unit 207 inkjet nozzle X0 axis M print medium

Claims (6)

[Claims] An ink jet nozzle disposed around the drum ejects ink onto a print medium held on the outer peripheral surface of a drum rotatable about an axis to form a printable medium. An ink jet printer comprising a wiping member for intermittently contacting an ink jet nozzle with rotation of a drum and removing ink attached to a discharge hole of the ink jet nozzle. 2. The ink jet printer according to claim 1, wherein said wiping member is formed by a plurality of blades extending in said axial direction and spaced apart in the circumferential direction on the outer peripheral surface of said drum. 3. The ink jet printer according to claim 1, wherein said wiping member is formed of a plurality of blades arranged on an outer peripheral surface of said drum in a circumferential direction and in an axial direction of said drum. 4. The ink jet printer according to claim 3, wherein each blade on the upstream side and each blade on the downstream side in the drum rotation direction in the circumferential direction of the drum are displaced in the axial direction. 5. The ink jet printer according to claim 2, wherein each of the blades is inclined in the axial direction and the circumferential direction. 6. The ink jet printer according to claim 2, wherein each of the blades is mounted on the drum so as to be able to protrude and retract in a radial direction of the drum.