JP2003021081A - Tube pump, and ink jet recording device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube pump capable of ensuring pump capacity for a long time by preventing occurrence of abrasion or crack of a flexible tube, and an ink jet recording device using the tube pump. SOLUTION: In this tube pump for generating pressure by deformation of the flexible tube 51 by press contact of rollers 43a and 43b, a pump frame 44 is provided with tube lead-out parts 71 and 81 and tube lead-in parts 72 and 82 tilting for the end surface of a pump wheel 42 on the roller installation side, and the flexible tube is inclined and held by a tube support surface 52 in response to the tilting angle of the tube delivering/introducing parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube pump for generating a pressure by utilizing the deformation of a tube, and an ink ejection capacity recovery means for sucking ink from a recording head by utilizing a negative pressure generated by the tube pump. The present invention relates to an inkjet recording device provided.

[0002]

2. Description of the Related Art Ink jet recording apparatuses have been used in many printings, especially color printings, because of their relatively low noise during printing and the ability to form small dots with high density. There is. Such an inkjet recording apparatus is provided with an inkjet recording head that receives supply of ink from an ink cartridge, and a paper feeding unit that relatively moves the recording paper with respect to the recording head. Then, recording is performed by moving the recording head in accordance with the print signal to eject ink droplets on the recording paper to form dots. In this case, a recording head capable of ejecting, for example, black, yellow, cyan, and magenta inks is mounted on the carriage, and full-color printing is possible by changing the ejection ratio of each ink.

Such an ink jet type recording apparatus has the following problems in relation to printing by ejecting ink as ink droplets from a nozzle opening onto a recording sheet. That is, clogging occurs in the nozzle opening due to increase in ink viscosity caused by evaporation of the ink solvent from the nozzle opening, solidification of ink on the nozzle forming surface, and adhesion of dust, and bubbles are mixed in the recording head. The problem is that printing defects occur.

Therefore, in the ink jet recording apparatus, in addition to the recording head and the paper feeding means described above, a capping means for sealing the nozzle forming surface of the recording head at the time of non-printing, and ink is sucked and discharged into the capping means. And a wiping unit that cleans the nozzle forming surface of the recording head after the ink is sucked and discharged by the suction pump. Then, in order to prevent the occurrence of clogging of the nozzle openings and the inclusion of air bubbles in the recording head, the suction pump forcibly sucks and discharges the ink from the recording head into the capping unit (the recovery process of the ink discharge capability). After that, the nozzle forming surface of the recording head is wiped by the wiping means.

The process of forcibly discharging the ink for eliminating the clogging of the recording head or when air bubbles remain in the recording head is called a cleaning operation. Then, it is executed when printing is resumed after a long pause in the recording apparatus, or when the user recognizes a print quality defect such as print blur and operates the cleaning switch. This cleaning operation is performed by applying a negative pressure to the inside of the capping means while the nozzle forming surface of the recording head is sealed by the capping means.

The means for applying a negative pressure to the capping means has a relatively simple structure and can be easily downsized.
Moreover, a so-called tube pump is used, which does not cause contamination in the mechanism for sucking and discharging ink. This tube pump is configured as shown in FIGS. 7 and 8, for example. Note that FIG. 7 shows a case where the pump is driven in the forward direction to bring it into a pump working state, and FIG. 8 shows a case where the pump is driven in reverse to put it into a release working state.

The tube pumps shown in both of these figures have a pump frame 44 having a tube support surface 52 for regulating the outer shape of a flexible tube 51 in an arc shape, a pump wheel 42 rotated by a paper feed motor, and the like. A pair of roller support grooves 42a, 4 formed in the pump wheel 42
And rollers 43a and 43b that move along 2b.

In such a tube pump, as shown in FIG. 7, when the pump wheel 42 is rotated in the forward direction (arrow A direction), the rollers 43a and 43b move toward the outer peripheral portions of the roller support grooves 42a and 42b. The flexible tube 51 is moved and rotated while being crushed (handled) in the direction of the arrow A in sequence. As a result, a pressure is generated in the flexible tube 51 to give a negative pressure to the capping means. Then, the ink is forcibly discharged from the recording head by a negative pressure, and the ink discharged into the capping means is sucked and sent to the waste ink tank.

On the other hand, as shown in FIG.
Is rotated in the opposite direction (arrow B direction), each roller 43
a and 43b move toward the inner peripheral portions of the roller support grooves 42a and 42b. As a result, the rollers 43a and 43b maintain a release state in which they are slightly in contact with the flexible tube 51,
Failures such as sticking of the rollers 43a and 43b to the flexible tube 51 are prevented.

In the embodiment shown in FIGS. 7 and 8, the pump frame 44 has an L-shaped engaging groove 44 in a plan view.
a and 44b are provided, and guide members 53a and 53b are locked in the locking grooves 44a and 44b, respectively.
Accordingly, the guide members 53a and 53b act so as to guide the rollers 43a and 43b in the wheel rotation backward direction of the roller support grooves 42a and 42b (the direction opposite to the wheel rotation direction) as the pump wheel 42 rotates. To do.

[0011]

By the way, in this type of tube pump, the flexible tube 51 is introduced and led out while being inclined with respect to the roller arrangement side end surface of the pump wheel 42 as shown by the broken line in FIG. Moreover, as shown by the solid line in the figure, the structure is such that the end face of the pump frame 44 on the roller arrangement side is held in close contact with the end face of the pump frame 44, and therefore the following problems are encountered. That is, the flexible tube 51 is held on the tube support surface 52 by bending the central portion (the portion where the rollers 43a and 43b come into pressure contact) in a direction away from the roller arrangement side end surface of the pump wheel 42. Therefore, the elastic return force that approaches the roller arrangement side end surface of the pump wheel 42 always acts on the flexible tube 51. Therefore, as the pump wheel 42 rotates, the flexible tube 51 moves to a position where it comes into contact with the roller arrangement side end surface of the pump wheel 42 due to its elastic restoring force as shown by the chain double-dashed line in FIG. is there.

When the flexible tube 51 at the position in contact with the end surface of the pump wheel 42 on the roller arrangement side is handled by the rollers 43a and 43b, the flexible tube 51 bulges in the axial direction of the pump wheel 42, This bulging portion of the tube is in a state of being pressed against the end surface of the pump wheel 42 on the roller arrangement side. When the pump drive is continued in this state, the flexible tube 51 is rubbed by the pump wheel 42, so that the peripheral wall of the flexible tube 51 is worn. In particular, when the flexible tube 51 comes into contact with the outer peripheral portion (tooth portion) of the pump wheel 42, it is significantly worn. As described above, when the wear of the flexible tube 51 progresses, a crack eventually occurs in the peripheral wall of the flexible tube 51, and it becomes impossible to obtain a pump negative pressure when the pump is driven. Could not be guaranteed.

The present invention has been made in view of the above circumstances, and it is possible to prevent the flexible tube from being worn or cracked and to ensure the pumping ability for a long period of time. Another object of the present invention is to provide an inkjet recording apparatus using the same.

[0014]

SUMMARY OF THE INVENTION A tube pump according to the present invention made to achieve the above object is a pump frame having a tube support surface for restricting the outer shape of a flexible tube in an arc shape, and this pump. A pump wheel having a roller support groove rotatably disposed in the frame and opening at the end face of the wheel, and a pump wheel that is rotatably and rotatably disposed in the pump wheel and is housed in the pump frame along the roller support groove. A tube having a movable roller shaft, wherein a pressure is generated by the deformation of the flexible tube due to the pressure contact of the roller, wherein the tube is inclined with respect to the roller arrangement side end surface of the pump wheel. Section and tube lead-out section are provided on the pump frame to match the inclination angles of these tube lead-in and lead-out sections. The serial flexible tube, characterized in that inclined held by the tube support surface.

With this construction, the elastic return force that comes into contact with the end face of the pump wheel on which the roller is arranged does not act on the flexible tube in the tube holding state,
The contact of the flexible tube with the pump wheel (the end surface on the roller arrangement side) due to the rotation of the pump wheel is avoided. Therefore, it is possible to prevent wear and cracks from occurring due to the contact of the flexible tube with the pump wheel, so that it is possible to reliably obtain the pump action force and guarantee the pump performance for a long period of time.

Here, it is preferable that the tube introducing section and the tube extracting section are arranged outside the tube contact area of the roller. With this configuration, the flexible tube is introduced into the pump frame from the tube introduction portion outside the tube contact area of the roller,
It is led out of the pump frame from a tube lead-out portion outside the tube contact area of the roller.

Further, it is desirable that the tube introducing portion and the tube extracting portion are formed by concave grooves. With this configuration, the flexible tube is introduced into the pump frame and is guided out of the pump frame by the concave groove. Then, an inclined surface is provided on the groove bottom of the concave groove. With this configuration, the flexible tube is introduced into the pump frame and is guided out of the pump frame by the inclined surface.
Further, a configuration in which a step portion is provided on the groove bottom of the concave groove can also be adopted. With this configuration, the step portion introduces the flexible tube into and out of the pump frame.

On the other hand, the ink jet type recording apparatus according to the present invention seals the ink jet type recording head for ejecting ink droplets corresponding to the print data, the nozzle forming surface of this recording head, and the negative pressure from the pump unit. An ink jet recording apparatus provided with a capping means for sucking and discharging ink from the recording head under pressure, characterized in that the tube pump is provided as the pump unit. With such a configuration, it is possible to obtain a pump unit that prevents abrasion and cracking of the flexible tube and guarantees pumping ability for a long period of time, and thus it is possible to increase the commercial value.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An ink jet recording apparatus using a tube pump according to the present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a perspective view showing the outline of the overall configuration of an ink jet recording apparatus to which the present invention is applied. In FIG. 1, a carriage indicated by reference numeral 1 is configured to be guided by a guide member 4 via a timing belt 3 driven by a carriage motor 2 so that the carriage can reciprocate in the axial direction of the platen 5. The guide member 4 is supported by two left and right frames 31 and 32 facing each other. Both frames 31, 32 are connected by a back plate 33 and a bottom plate 34.

An ink jet recording head 12 is mounted on the lower surface of the carriage 1 so as to face the recording paper 6. A black ink cartridge 7 and a color ink cartridge 8 for supplying ink to the recording head 12 are detachably held on the upper surface of the carriage 1.

A capping means 9 having a cap member 9a is arranged in a non-printing area (home position) in the moving area of the carriage 1. When the recording head 12 moves right above, the recording head 12 rises and the nozzle forming surface of the recording head 12 can be sealed. A tube pump 10 as a pump unit for applying a negative pressure to the internal space of the cap member 9a is arranged below the capping means 9.

The capping means 9 has a function as a lid for preventing the nozzle openings of the recording head 12 from drying during the rest period of the recording apparatus. Further, a drive signal that is not related to printing is applied to the recording head 12 to function as an ink receiver during a flushing operation in which ink droplets are ejected, and a negative pressure from the tube pump 10 is applied to the recording head 12 to cause ink to flow. It also has a function as a cleaning means for sucking.

An elastic plate (wiping member) made of rubber or the like is provided in the vicinity of the printing area side of the capping means 9.
The wiping means 11 provided with is arranged so as to be able to move forward and backward in the horizontal direction. Then, when the carriage 1 reciprocates on the side of the capping means 9, the wiping means 11 can be advanced on the movement path of the recording head 12.

Next, the tube pump 10 and the wiping means 11 will be described with reference to FIG. 2 is an exploded perspective view showing an assembly mechanism of a tube pump and a wiping means of an ink jet type recording apparatus to which the present invention is applied. In FIG. 2, the same members as those in FIG. The description is omitted. In FIG. 2, the tube pump 10 has a tube support surface (only one is shown) that regulates the outer shape of the flexible tube 51 into an arc shape.
52 includes a pump frame 44 having cylindrical portions 16a and 16b formed therein. Inside the cylindrical portions 16 a, 16 b of the pump frame 44, the pump wheel 4
2 is arranged so as to be able to rotate in the forward and reverse directions by receiving the driving force of the sheet feeding motor.

Each pump wheel 42 is provided with roller support grooves (through holes) 42a, 42b having a gradient so as to intersect in the radial direction of the wheel between the wheel central portion and the wheel outer peripheral portion. Then, these roller support grooves 42a,
Rollers 43a and 43b having roller shafts 43A and 43B capable of moving 42b are rotatably and rotatably disposed in the respective cylindrical portions 16a and 16b of the pump frame 44. As a result, the pumping action performed by the rollers 43a and 43b by pressurizing the flexible tube 51 against the tube supporting surface 52 and the releasing action in which the rollers 43a and 43b slightly contact the flexible tube 51 are selected.

An ink suction port (not shown) is provided at the bottom of the capping means 9 (cap member), and a flexible tube 51 is connected to this ink suction port. Accordingly, when the cleaning command is received, the negative pressure generated by the driving of the tube pump 10 acts so as to be applied to the internal space of the capping means 9.

On the other hand, the wiping means 11 constitutes a part of the cleaner drive unit (cleaner) 21. The cleaner drive unit 21 includes a clutch plate 21a, a cleaner cam 2 and a drive shaft (pump shaft) of a pump wheel 42.
1b and the compression spring 21c are loosely fitted and arranged between the base frame 21e and a pump cover (described later). Thereby, the cleaner cam 2 having the opening window 21f
1b is pressed against the clutch plate 21a by the compression spring 21c. Further, the pump cover 1 is mounted on the base frame 21e so that the slide member 21d holding the wiping means 11 can slide in the horizontal direction perpendicular to the head reciprocating direction.
It is attached via 0a. The slide member 21d is provided with a hook-shaped convex portion (not shown) facing the opening window 21f.

The cleaner cam 21b is provided with a pump wheel 42.
When the slide member 21d is rotated in one direction, the slide member 21d is dragged in the same direction via the clutch plate 21a to move the slide member 21d in one horizontal direction. Also, the cleaner cam 21b
Is dragged in the same direction through the clutch plate 21a by the rotation of the pump wheel 42 in the other direction, and acts so as to move the slide member 21d in the other horizontal direction.

As a result, the wiping means 11 operates so as to advance or retreat to the cleaning position on the head movement path by the forward / reverse rotation drive of the sheet feeding motor that drives the tube pump 10. In this case, the nozzle forming surface of the recording head 12 (shown in FIG. 1) is wiped when the wiping means 11 is in the state of being advanced to the cleaning position.

Next, the principal part of the ink jet type recording apparatus (tube pump) to which the present invention is applied will be described with reference to FIGS. 3 (a) and 3 (b) are plan views showing a tube pump according to the embodiment of the present invention and FIG.
FIG. FIGS. 4 (a) to 4 (c) are a front view, a BB cross-sectional view, and a C view showing the cylindrical portion (1) of the pump frame of the tube pump according to the embodiment of the present invention.
FIG. 5A to 5C are front views, EE cross-sectional views, and D-D showing the cylindrical portion (2) in the pump frame of the tube pump according to the embodiment of the present invention.
FIG. In these figures, the same members as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted. The pump frame 44 shown in FIGS. 3A and 3B has the cylindrical portions 16a and 16b as described above, and is entirely made of hard plastic.

A shaft insertion hole 70 through which the pump drive shaft 10b of the tube pump 10 is inserted is provided at the center of the cylinder bottom of the cylindrical portion 16a, and the outer shape of the flexible tube 51 is arcuate on the cylinder wall. Tube support surface 52 regulated to
Is provided. In addition, in the cylindrical portion 16a, as shown in FIG.
As shown in (a), a tube lead-out portion 71 and a tube lead-in portion for arranging the flexible tube 51 on the tube support surface 52 while inclining the flexible tube 51 with respect to the rotation center axis line (roller arrangement side end surface) of the pump wheel 42. A section 72 is provided.

The tube lead-out portion 71 has the roller 4
It is formed outside the tube contact areas of 3a and 43b, and is formed by a concave portion having a linear groove 71a for introducing the flexible tube 51 from inside the pump frame to outside the pump frame. Straight groove 71a in the tube lead-out portion 71
As shown in FIG. 4 (b), the groove bottom is gradually adjusted along the wheel axis line from the roller arrangement side end surface of the pump wheel 42 according to the inclination angle of the flexible tube 51 in the pump frame 44. An inclined surface 71b is provided that has a downward slope that separates, that is, a slope that descends from outside the pump frame toward inside the pump frame.

The tube introducing section 72 is arranged outside the tube contact area of the rollers 43a and 43b, like the tube extracting section 71. The flexible tube 51 is formed by a concave portion having a curved groove 72a and a straight groove 72b for leading the flexible tube 51 from the outside of the pump frame into the inside of the pump frame. At the groove bottom of the curved groove 72a in the tube introducing portion 72, as shown in FIG.
In accordance with the inclination angle of the flexible tube 51 in the pump frame 44, an upward slope that gradually approaches from the lower portion of the inclined surface 71b toward the roller arrangement side end surface of the pump wheel 42, that is, the pump frame. An inclined surface 72c having a slope that rises from the inside toward the outside of the pump frame is provided. Further, as shown in FIG. 7C, a flat surface 72d that is connected to the inclined surface 72c and is parallel to the roller arrangement side end surface of the pump wheel 42 is provided at the groove bottom of the linear groove 72b.

On the other hand, a shaft insertion hole 80 through which the pump drive shaft 10b of the tube pump 10 is inserted is provided at the center of the cylinder bottom of the cylindrical portion 16b, and the outer shape of the flexible tube 51 is formed on the cylinder wall. Is provided with a tube support surface 52 for restricting the arc shape. Further, in the cylindrical portion 16b, as shown in FIG. 5 (a), the flexible tube 51 is inclined with respect to the rotation center axis line (roller arrangement side end surface) of the pump wheel 42 so that the tube support surface 52 is provided. Tube lead-out portion 81 and tube lead-in portion 8 for holding
Two are provided.

The tube lead-out portion 81 has the roller 4
It is formed by a concave portion having a curved groove 81a which is arranged outside the tube contact regions of 3a and 43b and introduces the flexible tube 51 from inside the pump frame to outside the pump frame. Curved groove 81a in the tube lead-out portion 81
As shown in FIG. 5 (b), the groove bottom of the pump wheel 42 is gradually adjusted along the axis of the wheel from the end surface of the pump wheel 42 on the roller arrangement side in accordance with the inclination angle of the flexible tube 51 in the pump frame 44. An inclined surface 81b is provided that has a downward slope that separates, that is, a slope that descends from the outside of the pump frame toward the inside of the pump frame.

The tube introducing portion 82, like the tube extracting portion 81, is arranged outside the tube contact area of the rollers 43a and 43b. The flexible tube 51 is formed by a concave portion having a straight groove 82a and a curved groove 82b for leading the flexible tube 51 from the outside of the pump frame into the pump frame. At the groove bottom of the straight groove 82a in the tube introduction portion 82, as shown in FIG.
A flat surface 82c parallel to the end surface of the pump wheel 42 on which the rollers are arranged is provided. Further, at the bottom of the curved groove 82b, as shown in FIG.
4 in accordance with the inclination angle of the flexible tube 51 in the inside of 4, the slope gradually approaches from the inclined surface 81b toward the roller arrangement side end surface of the pump wheel 42,
That is, an inclined surface 82d having a slope rising from the inside of the frame to the outside of the frame is provided.

Even if the flexible tube 51 (the portion preceding the rollers 43a and 43b) is loosened toward the pump wheel by the extension of the rollers 43a and 43b due to the handling (pressure contact), the pump wheel 42 at the loosened portion of the tube It is assumed that a space for avoiding contact with the pump frame 44 is sufficiently secured in the wheel axis direction of the pump frame 44.

With the above construction, when the pump wheel 42 is rotated in the forward direction (pump acting direction), each roller 43 is rotated.
a and 43b move toward the outer peripheral portions of the roller support grooves 42a and 42b, and rotate and roll while squeezing (handling) the flexible tube 51 sequentially in the pump action direction (from the tube introducing portion to the tube extracting portion). Move. As a result, a pressure is generated in the flexible tube 51 and a negative pressure is applied to the internal space of the capping means 9. And
Ink is forcibly discharged from the recording head 12 by negative pressure, and the ink discharged into the capping means 9 is sucked and sent to the waste ink tank.

In this case, an elastic restoring force for contacting the end face of the pump wheel 42 on the roller arrangement side is applied to the flexible tube 5.
1, does not act on the pump tube 4 of the flexible tube 51
Contact with 2 is avoided. In addition, the rollers 43a and 43b
Even if the flexible tube 51 bulges in the axial direction of the wheel by the handling (pressure contact), the bulging portion of the tube is not pressed against the roller arrangement side end surface of the pump wheel 42. Therefore, in the present embodiment, it is possible to prevent abrasion and cracking due to the contact of the flexible tube 51 with the pump wheel 42, so that it is possible to reliably obtain the pump action force and to improve the pump performance for a long period of time. Can be guaranteed.

In this embodiment, the straight groove 71
Although the case where the inclined surface 71b is provided on the groove bottom of a has been described, the present invention is not limited to this, and is adjusted to the inclination angle of the flexible tube 51 in the pump frame 44, as shown in FIG.
As shown in (b) and (b), the stepped portion 91 may have a slope that rises from inside the frame to outside the frame. In this case, a stepped portion (not shown) may be provided in place of the inclined surface for the tube introduction portion 72 of the cylindrical portion 16a and the tube lead-out portion 81 and the tube introduction portion 82 of the cylindrical portion 16b.

[0041]

As is apparent from the above description, according to the tube pump and the ink jet type recording apparatus using the same of the present invention, it is possible to prevent the abrasion and crack generation due to the contact of the flexible tube with the pump wheel. Therefore, it is possible to guarantee the pumping ability for a long period of time.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of an overall configuration of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is an exploded perspective view showing an assembly mechanism of a tube pump and a wiping unit of an inkjet recording apparatus to which the present invention is applied.

3 (a) and 3 (b) are a plan view and an AA cross-sectional view showing a tube pump according to an embodiment of the present invention.

4A to 4C are a front view, a BB sectional view, and a CC sectional view showing a cylindrical portion (1) in the pump frame of the tube pump according to the embodiment of the present invention.

5A to 5C are a front view, an EE sectional view, and a DD sectional view showing a cylindrical portion (2) in the pump frame of the tube pump according to the embodiment of the present invention.

6 (a) and 6 (b) are a front view and a BB cross-sectional view shown for explaining a modified example of the tube introducing portion in FIG.

FIG. 7 is a perspective view showing a state in which a conventional tube pump is normally driven to perform a pumping action.

FIG. 8 is a perspective view showing a case where a conventional tube pump is also driven in reverse to bring it into a release state.

FIG. 9 is a cross-sectional view shown for explaining a defective example of a conventional tube pump.

[Explanation of symbols]

1 carriage 2 Carriage motor 3 Timing belt 4 Guide member 5 Platen 6 recording paper 7 Black ink cartridge 8 color ink cartridges 9 Capping means 9a Cap member 10 Pump unit (tube pump) 10a pump cover 10b drive shaft 11 Wiping means 12 recording head 16a, 16b Cylindrical part 21 Cleaner drive unit 21a clutch plate 21b cleaner cam 21c compression spring 21d slide member 21e base frame 42 pump wheel 42a, 42b Roller support groove 43a, 43b rollers 43A, 43B roller shaft 44 pump frame 51 flexible tube 52 Tube support surface 70 Shaft insertion hole 71 Tube outlet 71a straight groove 71b inclined surface 72 Tube introduction part 72a curved groove 72b Straight groove 72c inclined surface 72d flat surface 80 shaft insertion hole 81 Tube outlet 81a curved groove 81b inclined surface 82 Tube introduction part 82a straight groove 82b curved groove 82c flat surface 82d slope

Claims (6)

[Claims] 1. A pump frame having a tube supporting surface for restricting the outer shape of a flexible tube in an arc shape, and a pump wheel having a roller supporting groove rotatably disposed in the pump frame and opening at an end surface of the wheel. And a roller that is rotatably and rotatably arranged on the pump wheel, is housed in the pump frame, and has a roller shaft that is movable along the roller support groove. In a tube pump that generates pressure by the deformation of the flexible tube, a tube introduction part and a tube extraction part that are inclined with respect to the roller arrangement side end surface of the pump wheel are provided in the pump frame. The flexible tube is tilted and held on the tube supporting surface in accordance with the tilt angle. Buponpu. 2. The tube pump according to claim 1, wherein the tube introducing section and the tube extracting section are arranged outside a tube contact area of the roller. 3. The tube pump according to claim 1 or 2, wherein the tube introducing portion and the tube extracting portion are concave grooves. 4. The tube pump according to claim 3, wherein an inclined surface is provided on the groove bottom of the concave groove. 5. The tube pump according to claim 3, wherein a step portion is provided on the groove bottom of the concave groove. 6. An ink jet type recording head for ejecting ink droplets corresponding to print data, and a nozzle forming surface of the recording head is sealed, and a negative pressure from a pump unit is received so that the ink is ejected from the recording head. An ink jet recording apparatus provided with a capping unit for sucking and discharging the ink, the ink jet recording apparatus comprising the tube pump according to any one of claims 1 to 5 as the pump unit. apparatus.