JP2001063093A - Ink-jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet printer having a sucking part for more efficient suction by solving the problem of a change in driving torque of a tubing pump or fatigue of a rotation spindle of a roller. SOLUTION: The ink-jet printer in which ink is discharged from nozzles thereby forming images has a nozzle cap for covering the nozzles, and a sucking part provided with a tubing pump 700 for applying a negative pressure to the nozzles covered with the nozzle cap. The tubing pump has a tube held between (n) (n>=3) rollers 703 arranged to a circumferential edge of a rotary member and (n-1) of fewer rub faces present outside the periphery of the rotary member 704 to be opposite to the roller 703. The rollers 703 continuously press the tube to the ironing faces when the rotary member 704 rotates, whereby a negative pressure is generated. Each rub face has an ironing angle smaller than 360 deg./n to a rotation center of the rotary member 704.

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 forms an image by discharging ink from a nozzle, and more particularly, to an ink jet printer having a sucking portion for sucking and removing defective ink, dust, bubbles, etc. in a nozzle. .

[0002]

2. Description of the Related Art Heretofore, as an ink jet printer of this type, a nozzle cap for airtightly covering an ink discharge port of a nozzle from outside, and a negative pressure has been applied to the nozzle covered by the nozzle cap, so that the ink There is known a device provided with a sucking portion having suction means for sucking air. Since defective ink, dust, air bubbles, and the like in the nozzles can be removed and defective ink ejection can be prevented, a clear image can be formed.

As the suction means, a suction means using a tube pump is known. For example, JP-A-8-33698
No. 9 discloses an example of such a tube pump.

Specifically, a tube pump as shown in FIG. 10 is used. FIG. 10A is a front sectional view, and FIG.
Is an exploded perspective view. This tube pump is shown in FIG.
The peripheral edge of the disc-shaped cam plate 704 rotating in the direction of the arrow in FIG.
The two rollers 713 attached to the position of (1) and the substantially left half (ironed surface) of the inner wall of the wheel case 705 squeeze one tube 712 to generate a negative pressure. The upper end of the tube 712 in the drawing is connected to the nozzle, and the lower end of the tube 712 is connected to the waste ink tank.

The rotation of the cam plates 704a and 704b
The rotation motor 709 is engaged with the outer periphery of the cam plates 704a and 704b. In FIG. 10B, the wheel case 705, the cam plate (A) 704a, the tube (A) 712, and the two rollers
13, cam plate (B) 704b, support shaft 706, support bearing plate 7
07, a motor receiving plate 708 and a rotary motor 709.

In the tube pump of this type, when the ironing surface of the inner wall of the wheel case 705 has an ironing angle of 180 ° or more with respect to the rotation center of the cam plate 704, both of the two rollers 713 And when one roller 713 is used alone. Then, since the driving torque for rotating the cam plate 704 is twice different between the case of two rollers and the case of one roller, the rotation is likely to be unstable, and as a result, a problem that the pumping ability is not constant tends to occur ( Drive torque fluctuation). In addition, referring to FIG. 10A, since the direction in which the roller 713 presses against the ironing surface is always on the left side, the load applied to the rotating shaft of the roller 713 is always biased on the left side, and fatigue tends to accumulate. (Fatigue of the rotating shaft).

On the other hand, in this type of tube pump, if the ironing angle is set to less than 180 ° and the timing is always high with one roller 713, the above-mentioned fluctuation of the driving torque is solved, The shaft fatigue cannot be solved yet.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer having a sucking section, which solves the above-mentioned problems of the drive torque fluctuation of the tube pump or the fatigue of the rotating shaft of the roller, thereby achieving more efficient suction. To provide an ink jet printer provided with a sucking section for the printer.

[0009]

The object of the present invention has been achieved by the following constitutions.

[0010] 1. An ink jet printer that performs image formation by ejecting ink from a nozzle, comprising: a nozzle cap that covers the nozzle; and a sucking unit that includes a tube pump that applies a negative pressure to the nozzle covered with the nozzle cap. The pump comprises a tube between n (n ≧ 3) rollers arranged on the periphery of the rotating member and n-1 or less ironing surfaces located outside the periphery of the rotating member in opposition to the rollers. By rotating the rotating member, the roller continuously presses the tube against the ironing surface to generate a negative pressure, and each ironing surface rotates the rotating member. An ink jet printer having an ironing angle of less than 360 ° / n with respect to the center.

2. 2. The ink-jet printer according to claim 1, wherein the n-1 or less ironing surfaces are arranged substantially uniformly outside the periphery of the rotating member.

3. 3. The inkjet printer according to the above item 1 or 2, wherein the number of tubes sandwiched between the n rollers and the n-1 or less ironing surfaces is two or more.

4. The ironing angle of each ironing surface is 360
° / (n + 1) or more
The inkjet printer according to any one of the above.

5. The number of the rollers is three, the number of the ironing surfaces is two, and the number of the tubes is two, and the two ironing surfaces are arranged at 180 ° symmetrical positions with respect to the rotation center. Any one of the above 1 to 4, characterized in that
Ink jet printer according to any one of the above.

6. The number of the rollers is four, the number of the ironing surfaces is two, and the number of the tubes is two, and the two ironing surfaces are arranged at 180 ° symmetrical positions with respect to the rotation center. Any one of the above 1 to 4, characterized in that
Ink jet printer according to any one of the above.

[7] The number of the rollers is six, the number of the ironing surfaces is three, the number of the tubes is three, and the three ironing surfaces are arranged at a position of 120 ° with respect to the rotation center. The ink jet printer according to any one of the above items 1 to 4, which is characterized in that:

[0017]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

The ink jet printer according to the present embodiment produces a color proof image by discharging ink droplets on an image recording surface of a recording sheet in accordance with image data corresponding to color separation halftone document image data. Device.

First, the overall configuration of the color proof creating apparatus will be described with reference to FIGS. FIG. 1 is a schematic sectional view of a color proof creating apparatus according to an embodiment, FIG. 2 is a schematic perspective view of the internal structure of the color proof creating apparatus shown in FIG. 1, and FIG. is there.

In the recording sheet 1 on which an image is recorded by the color proof forming apparatus of the embodiment, the image recording surface is a surface on which the ink absorbing layer having a large amount of ink adsorbed per unit area is exposed. Is preferable, and thereby, good tone reproduction from high density to low density can be achieved. The surface of the recording sheet 1 opposite to the image recording surface is formed as a slippery surface.

The sheet cassette 500 accumulates and stores a plurality of recording sheets 1 so that the image recording surface faces upward.

A feed roller 410, which will be described later, feeds a plurality of stacked recording sheets from the uppermost one.

The recording sheets 1 are taken out one by one from the sheet cassette 500 and supplied to the drum 100,
0, the print head 200 ejects ink droplets on the recording sheet 1 held by the drum 100, and an image is recorded on the recording sheet 1.
Is discharged to the discharge tray 310.

Here, the shape of the holding surface of the drum 100 for holding the recording sheet 1 is substantially a cylindrical surface.

The drum 100 rotates around a substantially cylindrical axis.

“Cylindrical axis” and “cylindrical surface” are a cylindrical axis and a cylindrical surface in a geometrical sense. The cylindrical axis is a straight line, and the cylindrical surface is a circle on a plane perpendicular to the cylindrical axis. A surface formed by a straight line passing through the circumference and parallel to the cylinder axis.

The “holding surface” refers to a surface of a portion where the recording sheet 1 is held in an area where the recording sheet 1 is held, and
"The holding surface is substantially cylindrical" means that the recording sheet 1
The area where the recording sheet 1 is held in the area where the recording sheet 1 is held may be substantially a cylindrical surface, and the other area may not be substantially cylindrical, such as being concave or non-existent. Or a substantially cylindrical surface.

The recording sheet 1 may be held at all locations in the area where the recording sheet 1 is held. For example, a recording sheet such as a groove, a hole, a slit or a hole may be partially provided in the area where the recording sheet is held. Even if a portion that does not hold the recording sheet is provided, the portion that holds the recording sheet in the area that holds the recording sheet may be a substantially cylindrical surface.

"The holding surface is substantially a cylindrical surface"
Variation in the distance of the holding surface from the cylinder axis is within a range that does not substantially cause a problem in creating a color proof that can be used favorably for calibration. It is preferably within 0.5 mm or less, more preferably 0.3 mm or less (in particular,
(0.1 mm or less).

"Substantially rotate around the cylindrical axis of the drum" means that the cylindrical surface of the cylindrical surface rotates around the cylindrical axis, and the eccentricity (the distance of the rotary axis to the cylindrical axis) is favorably used for calibration. Eccentricity is within a range that does not substantially matter to create a color proof that can be
It is preferably within 0.5 mm or less.
It preferably falls within 3 mm or less (especially 0.1 mm or less).

The color proof creating apparatus according to the present embodiment converts the ejection of ink droplets from the print head 200 and the rotation of the drum 100 into continuous tone conversion image data of a color separation halftone document. Based on the obtained continuous tone image data, a color proof image corresponding to the color separation halftone document image data is recorded on the image recording surface of the recording sheet fixedly held on the outer peripheral surface of the drum 100. I do.

The recording sheets 1 are supplied to the drum 100 from a sheet cassette 500 disposed below the drum 100 and the discharge tray 310.

Feeding between the sheet cassette 500 and the drum 100, in which only the uppermost recording sheet 1 of the recording sheets 1 stacked in the sheet cassette 500 is fed while being separated by a difference in frictional force. A roller 410, a first conveying roller pair 420 for continuously nipping and conveying the recording sheet 1 in the width direction, a first supply guide 430 for guiding a surface of the recording sheet 1 opposite to the image recording surface, and recording. Second transport roller pair 4 for continuously nipping and transporting the width direction of sheet 1
40, a second supply guide 450 for guiding the surface of the recording sheet 1 opposite to the image recording surface, and the recording sheet 1
And a pressing roller 460 that presses at 00.
From the sheet cassette 500 to the drum 100, the recording sheet 1 is transported and supplied while being turned upside down.

The drum 100 has an outer peripheral surface for fixedly holding the wound recording sheet 1 with the image recording surface facing outward during image recording. Drum 100
Are arranged so that the cylindrical axis of the cylindrical surface is horizontal, and the cylindrical axis rotates about this cylindrical axis. The drum 100 is driven to rotate at a constant rotation speed by a motor (not shown) during image recording.

The carriage 230 includes the print head 20
0 is fixedly held.

As shown in FIG. 3, the print head 200 includes nozzle head tables 211, 213, 215, and 2
17 are provided, and the nozzle head bases 211 and 21 are provided.
At 3,215,217, two nozzle heads are provided.

That is, the nozzle head 221 and the nozzle head 222 are provided on the nozzle head base 211, and the nozzle head 223 and the nozzle head 2 are provided on the nozzle head base 213.
24, the nozzle head base 215 has the nozzle head 22
5 and a nozzle head 226, and a nozzle head base 217 is provided with a nozzle head 227 and a nozzle head 228.

Each of the nozzle heads 221 to 228 has
A plurality of nozzles 220 are arranged in a column axis direction of the drum 100 within a range narrower than the image recording width.

As shown in FIG. 2, the moving means for moving the print head 200 in the direction parallel to the cylindrical axis of the drum 100 over the image recording width includes a pulley 250 fixed to a motor shaft of a motor 240 and a pulley 250 rotatably. The carriage 230 is fixed to a belt 260 wound around the held pulley 270, and the motor 230 rotates the pulley 250 to
Is moved in the direction of the cylinder axis of the drum 100.

In this embodiment, the carriage 23
0 is movably engaged with the guide 245.
, And regulates the position of the carriage 230 (print head 200) in the direction perpendicular to the cylinder axis of the drum 100. That is, the print head 20
The rotation of 0 is stopped.

An ink container 271 to 278 is provided for each of the nozzle heads 221 to 228. Nozzle head 2
For each combination of the ink containers 271-278 and the corresponding ink containers 271-278, the nozzle heads 221-228 and the corresponding ink containers 271-278 are connected to the flexible pipe 29.
1, 292 are connected. And pipe 2
The ends 91 and 292 are connected through a tractor unit 295 having one end fixed to the carriage 230.

The color proof forming apparatus of the present embodiment rotates the drum 100 holding the recording sheet 1 at a predetermined position on the outer peripheral surface while rotating the print head 2.
00 discharges ink droplets in accordance with the color separation screen document image data, thereby recording a part of the image in the image recording area of the recording sheet 1 and moving the head section 210 by the head moving means to the cylindrical axis of the drum 100. , And alternately, the image in the entire image recording area of the recording sheet 1 is recorded.

After the image formation is completed, the motor 240 rotates the pulley 250 so that the carriage 230
Is moved in the cylindrical axis direction of the drum 100, the print head 200 is moved to the position above the maintenance unit 600,
Sucking, cleaning and capping are performed.

As shown in FIG. 1, the color proof creating apparatus according to the present embodiment employs a recording sheet 1 on which an image is recorded.
And a discharge tray 310 provided on the side of the discharge guide 350. The recording sheet 1 on which an image is recorded by the drum 100 is discharged to the discharge tray 310. Discharge.

The discharge guide 350 is provided on the drum 100
By guiding the surface of the recording sheet 1 opposite to the image recording surface from the side of the outer peripheral surface of the recording sheet 1 to the discharge tray 310, the recording sheet 1 released from being fixedly held by the drum 100 can be moved only by gravity. It leads to the discharge tray 310. And
The recording sheet 1 is placed on the discharge tray 310 with the image recording surface facing up.
To be discharged.

The discharge tray 310 has a plurality of recording sheets 1.
Can be accommodated. In addition, the discharge tray 310
The recording sheet 1 is provided obliquely so that the height on the drum 100 side is increased, and accommodates the discharged recording sheet 1 obliquely.

The discharge tray 310 has a bat 330 slidable in the direction indicated by the arrow in FIG.
Is slid and pulled out to accommodate the discharged recording sheet 1. When the sheet cassette 500 is replaced, the recording sheet 1 cannot be supplied from the sheet cassette 500. Therefore, the sheet cassette 500 is replaced while the butt 330 is pushed in, so that the sheet cassette 500 can be easily replaced. .

The print head 200 may be provided with a heating heater inside the drum 100, an infrared lamp at a position facing the discharge guide 350, or an infrared lamp next to the head section 210. The structure is such that the recording sheet 1 is dried before the recording sheet 1 is discharged to the discharge tray 310 after the ink droplet is discharged onto the image recording surface.

Next, the maintenance unit 600 will be described with reference to FIG. FIG. 4 shows the maintenance unit 6
It is a block diagram of the inside of the cover of No. 00.

Outside the one end face of the drum 100, the direction in which the guide 245 extends, that is, the print head 2
The two guides 50 are arranged in a direction substantially orthogonal to the scanning direction 00.
1,503 are arranged side by side.

A slide stage 505 is movably engaged with the guides 501 and 503.

The slide stage 505 is provided with an upper and lower stage 507 that can move in the vertical direction.
The cleaning unit 511 that cleans the print head 200, the sucking unit 513 that fills each nozzle 220 of the print head 200 with ink, and the capping unit 515 that closes the opening of each nozzle 220 of the print head 200 are substantially the same as the scan direction of the print head 200. They are arranged in orthogonal directions.

The surfaces of the cleaning unit 511, the sucking unit 513, and the capping unit 515 of the maintenance unit 600 correspond to the nozzles 22 of the print head 200.
0 is set so that the plane moves in parallel.

The operation at the time of maintenance of the color proof creating apparatus having the above configuration will be described.
Moves above the maintenance unit 600.

Next, the slide stage 505 is connected to the guide 5.
01, 503, and moves in the direction of arrow I in FIG. 4 to change any one of the cleaning unit 511, the sucking unit 513, and the capping unit 515 to the print head 2.
00 is located below the nozzle 220.

Then, the upper and lower stages 507 are raised, and maintenance is performed.

According to the above configuration, the cleaning unit 511, the sucking unit 513,
The capping unit 515 is disposed in a direction substantially perpendicular to the scanning direction of the print head 200, and the cleaning unit 511
By moving the sucking unit 513 and the capping unit 515 in a direction substantially orthogonal to the scanning direction of the print head 200, the width of the printing head 200 of the apparatus in the scanning direction is shortened, and the apparatus can be downsized. still,
Regardless of this mode, the maintenance unit may have a configuration in which, for example, a sucking / cleaning unit that performs both sucking and cleaning, and a capping unit are arranged in a direction substantially orthogonal to the scan direction of the print head.

Next, the sucking portion of the above-described maintenance unit will be described with reference to FIGS. FIG. 5 is a schematic cross-sectional view of the sucking section, and FIGS. 6 to 9 are schematic views showing the form of the tube pump of the sucking section.

In FIG. 5, reference numeral 200 denotes a print head, and 513 denotes a sucking section. Print head 20
0 has a nozzle head base 211, and although not shown, each nozzle head base 211 has a plurality of nozzles 220 as described with reference to FIG. The ink droplets are ejected from the nozzle head base 211 downward in the drawing. The sucking section 513 is provided for each nozzle head base 2 of the print head 200.
The nozzle cap 701 corresponding to the nozzle 11 has a nozzle cap 701, so that each nozzle of the nozzle head table 211 can be airtightly covered from the outside. This nozzle cap 701
When the suction is performed by the tube pump 700 while applying a negative pressure to the nozzle head 211, a negative pressure is applied to the nozzle cap 701, and defective ink, dust, bubbles, and the like can be removed from the coated nozzle by suction. It has become. With this mechanism, it is possible to prevent a defective ejection of ink droplets and form a clear image. The details of the tube pump 700 will be described later, but n (n ≧ 3)
The cam plate 704 (rotating member) which arranges the roller 703 on the periphery is rotated in the direction of the arrow, and the tubes 702a and 702b are continuously pressed by the roller 703 against the inner wall surface (ironing surface) of the wheel case 705. Doing (stripping) creates a negative pressure. The ink and the like sucked from the nozzles pass through the tubes 702a and 702b and are stored in a waste ink tank (not shown) located at a lower position in the figure.

FIG. 6 is a schematic diagram for explaining the structure of the tube pump of FIG. 6A is an explanatory diagram relating to the arrangement of a plurality of rollers on the periphery of the cam plate, FIG. 6B is an exploded perspective view of the tube pump, and FIG. 6C is an explanatory diagram relating to the ironing angle. The tube pump of FIG.
One is a configuration of two tubes.

In FIG. 6A, three rollers 703
Are arranged on the periphery of the cam plate 704 at intervals of 120 °.

In FIG. 6B, the wheel case 705, the cam plate (A) 704a, the tube (A) 702a, the three rollers 703, and the tube (B) 7 are shown from the front of the drawing.
02b, a cam plate (B) 704b, a support shaft 706, a support bearing plate 707, a motor receiving plate 708, and a rotary motor 709. Cam plate (A) 704a and cam plate (B) 704b
A gear (not shown) is formed on the outer circumference to connect to the rotary motor 709 via switching means (not shown). A pair of cam plates (A) 704a and cam plates (B) have cam grooves cut (3) on the periphery thereof by the number of rollers 703, and each cam groove passes through three rollers 703, respectively. The tubes 702a and 702b are sandwiched by the inner wall surface (ironing surface) of the wheel case located outside the periphery of the cam plate facing the roller 703, and are continuously pressed in the tube length direction. In the tube pump of FIG. 6, the ironing surface is 180 ° with respect to the rotation center of the cam plate.
Are located at symmetrical positions, and are evenly arranged with respect to the rotation center of the cam plate. By having a plurality of ironing surfaces and by uniformly arranging the plurality of ironing surfaces, the above-mentioned problem of fatigue of the rotating shaft of the roller can be solved. In addition, when a plurality of ironing surfaces are provided, it is possible to easily iron a plurality of tubes with a set of tube pumps in terms of design, so that a more efficient tube pump can be provided.

In the tube pump of FIG. 6, a pair of cam plates (A) 704a and cam plates (B) 704b rotate in the direction of the arrow in FIG. A negative pressure is generated from the top to the bottom in the figure. The roller 703 at this time is a tube 702a.
And 702b, the ironing angle (ironing angle) with respect to each ironing surface is 115 as shown in FIG.
°. The ironing angle is 360 ° / n = 360 ° / 3 =
By making it 115 degrees less than 120 degrees, a plurality of rollers
Since it is possible to avoid pressing one ironing surface at a time, it is possible to avoid driving torque fluctuation due to cam plate rotation.

The three cam grooves for passing the rollers 703 of the cam plate (A) 704a and the cam plate (B) 704b are minute due to the elastic contact between the tubes 702a, 702b and the rollers 703. It has a function of absorbing unnecessary vibration and preventing propagation to surrounding members.

FIG. 7 shows another embodiment of the tube pump. The number (n) of the rollers 703, the number and arrangement of the ironing surfaces, and the ironing angle are the same as those of the tube pump of FIG. 6, except that the tube 702c is integrated into one on the nozzle cap side, and the rollers 703 and This is a configuration in which an ironing portion by the wheel case 705 is branched into two. Compared to the negative pressure per tube pump in FIG.
It is possible to generate a double suction force. Other effects are the same as those in FIG.

FIG. 8 shows another embodiment of the tube pump. FIG. 8A is an explanatory diagram relating to the arrangement of the rollers on the periphery of the cam plate, and FIG. 8B is an explanatory diagram relating to the ironing angle of the tube. The tube pump of FIG.
One is a configuration of two tubes. Roller 703 cam plate 7
The arrangement at the periphery of 04 is 90% equally divided from the center of rotation.
° each angle. The ironing surfaces of the wheel case 705 are two upper and lower surfaces, and are evenly arranged at 180 ° symmetrical positions with respect to the rotation center of the cam plate. The ironing angle is 85 °, which is less than 360 ° / n as shown in the figure. Always facing 2
As one roller squeezes each tube and the other two opposing rollers remain free, there is no fluctuation in drive torque or uneven fatigue of the force applied to the shaft of the roller, and a stable negative pressure Can be generated. Further, since two tubes can be sucked by one set of tube pumps, mechanical simplification and efficiency can be achieved.

FIG. 9 shows another embodiment of the tube pump. FIG. 9A is an explanatory diagram relating to the arrangement of a plurality of rollers on the periphery of the cam plate, and FIG. 9B is an explanatory diagram relating to the ironing angle of the tube. The tube pump of FIG.
It has six rollers, three tubes, and three ironing surfaces.
The arrangement of the rollers 703 on the periphery of the cam plate 704 is at an angle of 60 ° equally divided with respect to the center of rotation, and the ironing angle is 55 ° which is less than 60 °. The three ironing surfaces are
The cam plates are arranged at equal intervals of 120 ° with respect to the rotation center of the cam plate to prevent fluctuations in driving torque. In addition, as with the tube pump of FIG. 8, three tubes can be suctioned by one set of tube pumps, so that the suction efficiency is improved and it is mechanically advantageous.

As a material for the tube, NBR, silicon, PVC, or the like can be preferably used. In this embodiment, the outer diameter of the tube is φ4 (mm) and the inner diameter is φ2.
(Mm).

As the material of the roller, SUS304 or SU
S416 can be preferably used. A roller having a diameter of about 3 to 8 (mm) and a length of about 4 to 10 (mm) can be preferably used.

[0070]

As described above, in the ink jet printer having the sucking portion, the problem of the fluctuation of the driving torque of the tube pump or the fatigue of the rotating shaft of the roller is solved, and the ink jet printer having the sucking portion for more efficient suction is provided. Things.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a color proof creating apparatus according to the present invention.

FIG. 2 is a schematic perspective view of the internal structure of the color proof creating device of FIG.

FIG. 3 is a view of the print head of FIG. 2 as viewed from its discharge direction.

FIG. 4 is a configuration diagram for explaining a maintenance unit of the color proof creating device of FIG. 1;

FIG. 5 is a schematic sectional view illustrating a sucking portion of the maintenance unit of FIG. 4;

FIG. 6 is a schematic view showing one embodiment of a tube pump of the sucking section of FIG.

FIG. 7 is a schematic view showing one embodiment of a tube pump of the sucking section of FIG.

FIG. 8 is a schematic view showing one embodiment of a tube pump of the sucking section of FIG.

FIG. 9 is a schematic view showing one embodiment of a tube pump of the sucking section of FIG.

FIG. 10 is a front sectional view and an exploded perspective view showing a tube pump of an ink jet printer having a conventional sucking section.

[Explanation of symbols]

 100 Drum 200 Printhead 211 Nozzle head base 220 Nozzle 513 Sucking part 600 Maintenance unit 700 Tube pump 701 Nozzle cap 702 Tube 703 Roller 704 Cam plate (rotating member) 705 Wheel case

Claims (7)

[Claims] 1. An ink-jet printer that forms an image by discharging ink from a nozzle, wherein a sucking unit including a nozzle cap that covers the nozzle and a tube pump that applies a negative pressure to the nozzle covered with the nozzle cap is provided. The tube pump has n (n ≧ 3) rollers arranged on the periphery of the rotating member, and n-1 or less ironing surfaces located outside the periphery of the rotating member in opposition to the rollers. By sandwiching the tube between and rotating the rotating member, the roller continuously presses the tube against the ironing surface to generate a negative pressure, wherein each ironing surface is 36 with respect to the center of rotation of the rotating member
An ink jet printer having an ironing angle of less than 0 ° / n. 2. The ink jet printer according to claim 1, wherein the n-1 or less ironing surfaces are arranged substantially uniformly outside the periphery of the rotating member. 3. The ink jet printer according to claim 1, wherein two or more tubes are sandwiched between the n rollers and the n-1 or less ironing surfaces. 4. The ironing angle of each ironing surface is 360 °.
/ (N + 1) or more.
The inkjet printer according to any one of the above. 5. The number of the rollers is three, the number of the ironing surfaces is two, and the number of the tubes is two, and the two ironing surfaces are at 180 ° symmetrical positions with respect to the rotation center. 5. An arrangement according to claim 1, wherein said arrangement is made.
An inkjet printer according to the item. 6. The number of the rollers is four, the number of the ironing surfaces is two, and the number of the tubes is two, and the two ironing surfaces are at 180 ° symmetrical positions with respect to the rotation center. 5. An arrangement according to claim 1, wherein said arrangement is made.
An inkjet printer according to the item. 7. The number of the rollers is six, the number of the ironing surfaces is three, and the number of the tubes is three, and the three ironing surfaces are arranged at a position of 120 ° with respect to the rotation center. The inkjet printer according to any one of claims 1 to 4, wherein: