JP2000018165A - Tube pump and image formation unit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of pulsation in the fluid that is transferred in the tube with a motor of small driving torque for a tube pump having a plurality of tubes. SOLUTION: In these tube pumps 24a, 24b where an elastic tube for transferring fluid, a circular tube guide for retaining this tube, rotors 27a to 27f, and a plurality of pressurizing rollers 28a to 28f are disposed in parallel. The rotors 27a to 27f are disposed to be driven in such a way that they sandwich the tube with the tube guide. The pressurizing rollers 28a to 28f, for pressing the tube to the tube guide, are disposed at regular intervals on the rotors 27a to 27f and project from the outer periphery of the rotors 27a to 27f. The tube pumps 24a, 24b transfer the fluids in the plurality of tubes respectively by driving to rotate the plurality of the rotors 27a to 27f. Rotational phases of the pressurizing rollers 28a to 28f of the plurality of the rotors 27a to 27f are displaced alternately. Thus the timing of starting pressurization of the tube by each of the pressurizing rollers 28a to 28f is made to differ.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc tube guide and a rotatable rotor, which sandwich a flexible tube, and crush the tube by a pressing roller projecting from the outer peripheral surface of the rotor. The present invention relates to a tube pump adapted to convey a fluid, and an image forming apparatus equipped with the tube pump.

[0002]

2. Description of the Related Art Ink jet printers for forming a desired image by ejecting ink or a processing liquid for adjusting the characteristics of the ink onto paper, cloth, resin, metal, or the like, employ an ink jet head having such a print head. Since it is not in contact with the medium, it has advantages such as excellent quietness, high printing speed, high density printing, easy colorization, and downsizing of the entire apparatus. Above all, thermal energy is applied to the liquid, and the liquid is rapidly heated to generate air bubbles.The volume expansion of the air bubbles causes the liquid in the liquid path to be ejected from the discharge port as droplets. An ink jet head configured to introduce a liquid from a chamber into a liquid path has good responsiveness to a print signal and is easy to achieve high multi-head.

In such an ink-jet printer, a liquid supply mechanism for circulating and supplying a liquid to the ink-jet head is incorporated. As a pump for this, an arc-shaped tube guide and a rotatable driving rotor are used. In general, a tube pump that sandwiches the tube and crushes the tube with a pressing roller protruding from the outer peripheral surface of the rotor, thereby conveying the liquid in the tube is generally adopted.

FIG. 7 shows a front view of a main part of such a conventional tube pump. That is, a plurality of (six in the illustrated example) rotors 2a, 2b, 2c, 2d, 2e, and 2f are attached in parallel to the rotating shaft 1 connected to a motor (not shown), and are attached to the rotors 2a to 2f in parallel. Represents a plurality of (generally three) pressing rollers 3a, 3b, 3
c, 3d, 3e, and 3f are rotatably accommodated. Each of the pressing rollers 3a to 3f protrudes radially outward from the outer peripheral edge of each of the rotors 2a to 2f.
The pressing rollers 3a to 3f roll along the tube guides while crushing tubes (not shown) held between the tube guides (not shown) and the rotors 2a to 2f, respectively. By doing so, liquids interposed in the respective tubes are conveyed simultaneously.

[0005]

In the case of the conventional tube pump shown in FIG. 7, since the rotational phases of the pressing rollers 3a to 3f attached to the rotors 2a to 2f are all set to the same phase, Is driven to rotate the rotors 2a to 2f together with the rotating shaft 1, all the pressing rollers 3a to 3f start crushing the tubes at the same time. As a result, when the number of tubes is particularly large as in the illustrated example, a large impact force is generated along with this, and when a motor having a small driving torque is used, uneven rotation is caused on the rotating shaft 1. As a result, pulsation of the liquid conveyed in the tube occurs, which has various adverse effects on the printing operation or increases the amount of heat generated by the motor, and therefore, some heat measures are required.

For this reason, generally, a motor having a sufficiently large driving torque is used and the capacity of a motor driver for driving the motor is increased. This causes problems such as an increase in manufacturing cost and an increase in the weight and size of the device.

[0007]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a tube pump capable of smoothly transporting a fluid in a tube by a motor having a low driving torque even if it has a plurality of tubes.

Another object of the present invention is to provide an image forming apparatus equipped with such a tube pump.

[0009]

According to a first aspect of the present invention, there is provided:
A flexible tube for transporting a fluid, an arcuate tube guide holding the tube, a rotor arranged and driven by the tube guide so as to sandwich the tube, A plurality of pressing rollers for pressing the tube against the tube guide are arranged in parallel with a plurality of pressing rollers provided at intervals and projecting from the outer peripheral surface of the rotor, and the plurality of tubes are driven by rotating the plurality of rotors. A tube pump configured to convey the fluid in each of the plurality of rotors, wherein the rotation phases of the pressing rollers of the plurality of rotors are shifted from each other so that the pressing start timings of the tubes by the pressing rollers of the respective rotors are different. It is characterized by having made it.

According to a second aspect of the present invention, a plurality of types of liquids are circulated and supplied to at least one liquid discharge head having a plurality of types of discharge ports for discharging a plurality of types of liquids. An apparatus for forming an image on a print medium using the liquid head, comprising a liquid supply unit, the liquid supply unit comprising: a flexible tube for transporting a liquid; and a circle holding the tube. An arcuate tube guide, a rotor arranged and driven so as to sandwich the tube between the tube guides, and a rotor arranged at equal intervals on the rotor and protruding from the outer peripheral surface of the rotor, respectively. A plurality of pressing rollers for pressing against the guide are arranged in parallel, and a plurality of the rotors are driven and rotated to remove the liquid in the plurality of tubes. Having a tube pump adapted to convey and shift the rotation phases of the pressing rollers of the plurality of rotors to each other so that the timing of starting the pressing of the tube by the pressing rollers of the respective rotors is different. It is a feature.

According to the present invention, when each of the rotors is driven and rotated, the pressing start timings of the tubes by the pressing rollers of the rotors are different from each other, and the impact force transmitted to the rotor via the pressing rollers is dispersed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a tube pump according to a first embodiment of the present invention, the tube pump has one drive shaft for driving rotation,
The plurality of rotors may be connected to the drive shaft such that the rotational phases of the pressing rollers of the plurality of rotors are shifted from each other with respect to the drive shaft. Also,
A plurality of drive shafts respectively connected to the plurality of rotors and capable of independently rotating; adjusting a drive timing of the plurality of drive shafts to start pressing the tube by the pressing rollers of the rotors; The timing may be different.

In the image forming apparatus according to a second aspect of the present invention, the image forming apparatus has one drive shaft that rotates and rotates, and the rotational phases of the pressing rollers of the plurality of rotors are shifted from each other with respect to the drive shaft. The plurality of rotors may be connected to the drive shaft. In addition, it has a plurality of drive shafts which are connected to the plurality of rotors and can rotate independently, and adjusts the drive timing of the plurality of drive shafts to adjust the drive timing of the tube by the pressing rollers of the respective rotors. The pressing start timing may be different.

[0014] The liquid may be ink or a processing liquid for adjusting printability of the ink on the print medium.

The liquid discharge head may have a discharge energy generating section for discharging liquid from the discharge port, and in this case, the discharge energy generating section may generate heat energy by electrothermal conversion. It is preferred to have a body.

[0016] The discharge ports of the liquid discharge head may be arranged over the entire width of a print area of the print medium.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the image forming apparatus according to the present invention is applied to an ink jet printer will be described in detail with reference to FIGS. 1 to 6, but the present invention is not limited to such an embodiment, It can be combined and applied to technologies in other fields that have similar issues.

As shown in FIG. 1 showing the concept of this embodiment,
A plurality of inkjet heads 12 (only one is shown in the drawing, in which discharge ports (not shown) are arranged downward over the entire width of the print area of the sheet material 11 as a print medium and are opened downward. Are arranged side by side in a direction perpendicular to the sheet material 11), and can be moved by a head moving means (not shown) between a retracted position shown in the drawing and a print position facing the sheet material 11. After moving to the retreat position and immediately below the inkjet head 12,
Prior to the printing operation, a processing liquid (hereinafter, these are collectively referred to as ink for convenience) for adjusting the printability of the ink discharged from an ejection port (not shown) of the ink jet head 12 or the sheet material 11 to the sheet material 11. The ink receiver 13 for receiving each ink jet head 1
In this recovery process, the ejection ports of the ink jet heads 12 and the liquid passages communicating with the ejection ports are cleaned, and good print quality for the sheet material 11 can be secured. The sheet material 11 placed on the transport belt 14 is transported by the transport belt driving unit 15 in a direction perpendicular to the paper surface in the drawing, and ink ejected from the discharge ports of the inkjet head 12 at the print position. Thus, predetermined image information is printed. Immediately above the transport belt 14, a sheet retainer 16 for preventing the sheet material 11 from floating from the surface of the transport belt 14 is provided, and the sheet retainer 16 causes the sheet material 11 to be discharged to an ejection port of the inkjet head 12 at a printing position. Care is taken to avoid contact.

Each ink jet head 12 has an ink supply / discharge tube 18 whose base end communicates with an ink tank 17.
The ink circulation supply pipe 19 and the ink circulation supply pipe 19 communicate with each other, and the ink receivers 13 also communicate with the ink tank 17 via the ink discharge pipe 20. Further, an ink tank 17 and a replaceable ink cartridge 2 for storing ink supplied to the ink tank 17 respectively.
1 is communicated with each other via an ink supply pipe 22 and an ink return pipe 23.

In the middle of each of the ink circulation supply pipes 19 and the ink supply pipes 22, tube pumps 24a and 24 are provided.
4b, the ink in the ink cartridge 21 is supplied into the ink tank 17 via the ink supply pipe 18 by the normal operation, and the excess ink is supplied into the ink cartridge 21 via the ink discharge pipe 20. On the other hand, the ink in the ink tank 17 is supplied to the inkjet head 12 via the ink circulation supply pipe 19 while being returned,
After passing through the inside, the ink supply / discharge pipe 18 returns to the inside of the ink tank 17 again, and the inside of the inkjet head 12, the inside of the ink supply / discharge pipe 18, and the inside of the ink circulation supply pipe 19 are cleaned.

During the printing operation, the operation of the tube pumps 24a and 24b is stopped, and the ink in the ink tank 17 is supplied and discharged by the capillary phenomenon as the ink discharged from the discharge port of the ink jet head 12 is consumed. The ink is sucked from the tube 18 into the inkjet head 12.
Reference numeral 25 in the drawing denotes a power supply mechanism for turning on / off the power supply of the inkjet printer in the present embodiment.

The above-described tube pumps 24a, 24b
In this embodiment, three pairs are provided corresponding to the numbers of the ink circulation supply pipes 19 and the ink supply pipes 22. The front shape of the main part is shown in FIG. 2, and the schematic structure is shown in FIG. That is, a plurality of (six in the illustrated example) rotors 27a, 2 are provided on the rotating shaft 26 connected to a pump driving motor (not shown).
7b, 27c, 27d, 27e, and 27f are attached in parallel, and a plurality (generally three) of pressing rollers 28a, 28b,
28c, 28d, 28e, 28f are rotatably accommodated. These pressing rollers 28a to 28f are equally spaced from each other (1 in the illustrated example) while protruding radially outward from the outer peripheral edges of the rotors 27a to 27f.
(Every 20 degrees) and are urged radially outward by the compression spring 29 from the rotors 27a to 27f, respectively. The press rollers 28a to 28f roll along the tube guide 30 while crushing the ink circulation supply pipe 19 and the ink supply pipe 22 held between the tube guide 30 and the rotors 27a to 27f. Thereby, the inks interposed in the respective ink circulation supply pipes 19 and the ink supply pipes 22 are simultaneously conveyed.

In this embodiment, the above-described ink circulation supply pipe 19 and ink supply pipe 22 are wound around rotors 27a and 27b, and the other two systems of ink circulation supply pipes and ink supply pipes (not shown) are connected to rotors 27c to 27f. Is wound around each.

Each of the rotors 27a to 27 with respect to the rotating shaft 26
The rotation phases of the pressing rollers 28a to 28f are shifted in the same direction by 20 degrees between the adjacent rotors, whereby the pressing of the pressing rollers 28a to 28f against the ink circulation supply pipe 19 and the ink supply pipe 22 is started. The timings are all different so that the impact force associated with the start of pressing can be completely dispersed. As a result, there is no uneven rotation of the rotation shaft 26, and the ink in the ink circulation supply pipe 19 and the ink in the ink supply pipe 22 is smoothly transported without pulsation. In addition, a motor drive having a smaller driving torque than the conventional one can be used as a pump drive motor for driving the rotating shaft 26, and a motor driver having a small capacity can be used. A reduction in size and weight can be achieved.

In the embodiment described above, all the rotors 27
The rotation phases of the pressing rollers 28a to 28f of a to 27f are shifted. However, when a pulsation or a pump drive motor having a relatively large rating can be adopted, or when the influence of pulsation is small, Rotors 27a to 27f
It is not necessary to shift the rotation phases of the pressing rollers 28a to 28f, and the rotation phases of the pressing rollers of the rotor may be shifted for each ink supply system.

FIG. 4 shows the shape of the main part of another embodiment of such a tube pump according to the present invention, and FIG. 5 schematically shows the rotational phase distribution of the pressing roller, which is the same as in the previous embodiment. The same reference numerals are given to the members having the functions, and the duplicate description will be omitted. That is, in the present embodiment, for each ink supply system, there is a press roller 28a, 28b of the rotor 27a, 27b, a press roller 28c, 28d of the rotor 27c, 27d, and a press roller 28e, 28f of the rotor 27e, 27f. Although the rotation phases are shifted by 40 degrees, the same effect as in the previous embodiment can be obtained in this case as well.

In the above-described two embodiments, all the rotors 27a to 27f are integrally connected to one rotating shaft 26 in a state where the rotating phases thereof are adjusted.
It is also possible to apply the present invention to a type in which each of 7a to 27f is rotatable.

FIG. 6 shows the shape of the main part of another embodiment of such a tube pump according to the present invention. Members having the same functions as those of the previous embodiment are designated by the same reference numerals. Duplicate description will be omitted. That is, one pump drive motor is connected to the rotating shafts 26a to 26f integral with the respective rotors 27a to 27f via a power distribution mechanism (not shown). Rollers 28a to 28f of the respective rotors 27a to 27f with respect to the ink supply pipes
Are adjusted so that the pressing start timings of the different times are different.

As a result, even when the pump drive motor is operated, the pressing start timings of the pressing rollers 28a to 28f with respect to the ink circulating supply pipe and the ink supply pipe are all different, and the impact force accompanying this pressing start is completely dispersed. It is possible.

[0030]

According to the tube pump of the present invention, the rotation phases of the pressing rollers of a plurality of rotors are shifted from each other so that the timing of starting the pressing of the tubes by the pressing rollers of the respective rotors is different. As a result, it is possible to drive a plurality of rotors smoothly evenly by using a motor having a small driving torque, and to reduce the pulsation of the fluid conveyed in the tube. Can be prevented.

Further, according to the image forming apparatus of the present invention, by mounting the above-described tube pump, it is possible to realize a small and low power consumption image forming apparatus at low cost.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a schematic configuration of an embodiment in which an image forming apparatus according to the present invention is applied to an ink jet printer.

FIG. 2 is a front view showing an appearance of a main part of the tube pump in the embodiment shown in FIG.

FIG. 3 is a conceptual diagram of a mechanism showing a schematic structure of the tube pump shown in FIG. 2;

FIG. 4 is a front view showing an appearance of a main part of another embodiment of the tube pump according to the present invention.

FIG. 5 is a conceptual diagram showing a rotation phase of a pressing roller in the embodiment shown in FIG.

FIG. 6 is a front view showing an appearance of a main part of still another embodiment of the tube pump according to the present invention.

FIG. 7 is a front view illustrating an appearance of a main part of a conventional tube pump.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 sheet material 12 inkjet head 13 ink receiver 14 transport belt 15 transport belt driving means 16 sheet presser 17 ink tank 18 ink supply / discharge pipe 19 ink circulation supply pipe 20 ink discharge pipe 21 ink cartridge 22 ink supply pipe 23 ink return pipe 24a, 24b Tube pump 25 Power supply mechanism 26, 26a to 26f Rotary shaft 27a to 27f Rotor 28a to 28f Press roller 29 Compression spring 30 Tube guide

Continued on the front page (72) Inventor Yuichi Takahashi 5540-11 Sakate-cho, Mizukaido-shi, Ibaraki F-term (reference) in Canon Aptex Co., Ltd. 2C056 KA04 3H077 AA06 CC04 CC10 CC17 EE04 EE34 EE36 FF07 FF38 FF42

Claims (10)

[Claims] 1. A flexible tube for transporting a fluid, an arcuate tube guide for holding the tube, and a rotor arranged and driven by the tube guide so as to sandwich the tube. A plurality of pressing rollers for pressing the tube against the tube guide are arranged in parallel with a plurality of pressing rollers disposed at equal intervals on the rotor and projecting from the outer peripheral surface of the rotor, and driving and rotating the plurality of rotors. A tube pump configured to convey fluid in the plurality of tubes by rotating the pressing rollers of the plurality of rotors with respect to each other, and pressing the tubes by the pressing rollers of the rotors. A tube pump having a different start timing. 2. A drive shaft for driving and rotating, wherein the plurality of rotors are connected to the drive shaft such that the rotational phases of the pressing rollers of the plurality of rotors are mutually shifted with respect to the drive shaft. The tube pump according to claim 1, wherein And a plurality of drive shafts respectively connected to the plurality of rotors and rotatable independently of each other. The drive timing of the plurality of drive shafts is adjusted to adjust the drive timing of each of the rotors. 2. The pressing start timing of said tube is made different.
A tube pump according to item 1. 4. A liquid supply means for circulating and supplying a plurality of types of liquids to at least one liquid discharge head having a plurality of types of discharge ports for discharging a plurality of types of liquids, respectively. An apparatus for forming an image on a print medium using a liquid head, wherein the liquid supply unit has a flexible tube for transporting a liquid, an arc-shaped tube guide for holding the tube, A rotor that is arranged and driven so as to sandwich the tube with a tube guide, and a plurality of rotors disposed at equal intervals on the rotor and projecting from the outer peripheral surface of the rotor to press the tube against the tube guide. A plurality of pressing rollers are arranged in parallel, and a plurality of the rotors are driven to rotate to convey the liquid in the plurality of tubes, respectively. An image forming apparatus comprising a tube pump, wherein the rotation phases of the pressing rollers of the plurality of rotors are shifted from each other so that the timings at which the pressing rollers of the rotors start pressing the tubes are different. . 5. A single drive shaft for driving rotation, wherein the plurality of rotors are connected to the drive shaft such that the rotational phases of the pressing rollers of the plurality of rotors are mutually shifted with respect to the drive shaft. The image forming apparatus according to claim 4, wherein: 6. A plurality of drive shafts respectively connected to the plurality of rotors and rotatable independently, and drive timings of the plurality of drive shafts are adjusted to adjust the drive timing of each of the rotors by the pressing roller. 5. The pressing start timing of said tube is made different.
An image forming apparatus according to claim 1. 7. The image forming apparatus according to claim 4, wherein the liquid is ink or a processing liquid for adjusting printability of the ink on the print medium. 8. The image forming apparatus according to claim 4, wherein said liquid discharge head has a discharge energy generating section for discharging liquid from said discharge port. 9. The image forming apparatus according to claim 8, wherein the discharge energy generation unit has an electrothermal converter that generates heat energy. 10. The ejection port of the liquid ejection head,
The image forming apparatus according to claim 4, wherein the image forming apparatus is arranged over the entire width of a print area of the print medium.