JPH08150726A - Ink jet printer - Google Patents

Abstract

PURPOSE: To provide an ink jet printer not generating the application of stress to a nozzle tube connection part and imparting good printing quality. CONSTITUTION: In an ink jet printer equipped with a printing head 1 having nozzles 2 and the nozzle tubes connected to the nozzles 2, a curved part 32 is formed to each of the nozzle tubes and the fixing parts 41, 42 fixing each of the ink tubes on both sides of the curved part 32 through damping materials are provided.

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, and more particularly to a piezo type ink jet printer.

[0002]

2. Description of the Related Art Ink jet printers are known as non-impact printers. An ink jet printer pressurizes ink and discharges it onto a recording medium, and a piezo ink jet printer uses a piezo (electrostrictive) element as a means for atomizing the ink. FIG. 4 is a conceptual diagram for explaining the configuration of an inkjet printer. In the figure, ink is sent from an ink tank (not shown) to a pressure tube 6 by a pressure pump 7, and a filter 5 for preventing dust from flowing into the head. And is supplied to the nozzle 2 through the nozzle tube 3. The nozzle 2 discharges the ink 21 to the recording medium 8 based on the recording information to perform printing.

FIG. 5 is a schematic view for explaining a head used in a piezo type ink jet printer. As a nozzle for ejecting ink to the recording medium, as shown in FIG.
Is known. The nozzle is provided with a piezo element 23 in a pressure chamber 25 in which minute nozzle holes are formed. By applying a voltage from the signal source 24 to the piezo element 23, the pressure in the pressure chamber 25 is changed to eject ink. Is being controlled. Further, FIG. 5B shows the outline of the configuration of another nozzle, which has a structure in which a cylindrical piezo element 23 is attached, and ink is ejected in the same manner as the nozzle. A nozzle tube 3 is connected to these nozzles, and ink is supplied through the nozzle tube 3.

FIG. 7 is a schematic configuration diagram of a print head of a conventional ink jet printer. The nozzle 2 is fixed to a print head frame 11 and is rotatably supported by a rotary shaft 14 attached to the print head frame 11. Has been done. FIG. 7A shows a print mode state in which printing is performed on a recording medium (not shown) arranged below, and the rotary shaft 14 is moved in the direction of the arrow by a drive mechanism (not shown). When rotated, the print head frame 11
The nozzle 2 installed on the recording medium is oriented with its nozzle hole facing the recording medium. Further, FIG. 7B shows a standby mode state in which printing on the recording medium is not performed,
The rotary shaft 14 is rotated in the direction opposite to the arrow in FIG. 7A to move the nozzle hole 22 to a position where it is removed from the recording medium. In this standby mode, the ejection state of the ink ejected from the nozzle 2 is inspected and adjusted.

[0005]

However, the conventional ink jet printer has a problem that the printing accuracy is deteriorated by the stress generated in the nozzle tube. The vibration source of the stepping motor and other components for driving the print head vibrates the nozzle tube, and further vibrates the print head connected to the nozzle tube, which causes deterioration of print quality. The vibration transmitted from the vibration source to the nozzle tube is mainly transmitted to the nozzle tube via the fixing portion that fixes the nozzle tube. Therefore, in the conventional inkjet printer, the vibration transmitted to the nozzle tube via the fixing portion of the nozzle tube is removed by adopting a configuration in which the nozzle tube is not fixed.

However, since the nozzle tube is not fixed, when the rotary shaft is rotated to move the nozzle to the position of the print mode or the standby mode as described above, the nozzle tube is connected with the movement. Deformation such as bending or twisting occurs in the nozzle tube, and stress is generated in the nozzle tube connecting portion connecting the nozzle and the nozzle tube. In FIG. 6 and FIG. 7, when the nozzle is rotated with the rotating shaft 14 as the center of rotation of the head to switch the mode, the nozzle tube 3 is deformed because it is not fixed, and stress is applied to the nozzle tube connecting portion 31. To be done. This stress causes an error in the position of the nozzle 2 and reduces print quality. Therefore, the print quality in the print mode is different from the print quality in the standby mode, and it becomes difficult to effectively adjust the print quality.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional ink jet printer, and to provide an ink jet printer having good print quality in which no stress is applied to the nozzle tube connecting portion.

[0008]

SUMMARY OF THE INVENTION The present invention is an ink jet printer having a print head having a nozzle and a nozzle tube connected to the nozzle, and a curved portion formed on the nozzle tube and a nozzle sandwiching the curved portion. The above object is achieved by providing a fixing portion for fixing the tube via a vibration damping material. The inkjet printer of the present invention is a printer that performs printing by supplying ink to nozzles via a nozzle tube and ejecting the ink onto a recording medium.

The nozzle tube of the present invention is fixed by a vibration damping member on the side opposite to the nozzle tube connecting portion connecting the nozzle and the nozzle tube, and stress is applied to the nozzle tube connecting portion. It also prevents vibration and absorbs vibration. Further, the curved portion formed in the nozzle tube of the present invention is provided at a position sandwiched by the fixing portions that fix the nozzle tube, and is deformed and absorbed by the displacement of the nozzle tube caused by the movement of the print head or the like, and the nozzle tube is connected. It prevents the stress from being applied to the part.

According to an embodiment of the present invention, the fixing portion of the nozzle tube includes a cylindrical vibration damping portion that encloses the outer periphery of the nozzle tube and a fixing tool that fixes the vibration damping portion. The vibration applied to the tube can be absorbed, and the displacement of the nozzle tube can be transmitted to the bending portion to absorb the stress in the bending portion. According to another embodiment of the present invention, the fixing portions for fixing the curved portion are sandwiched so that the installation directions thereof intersect with each other, whereby the curved portion of the nozzle tube can be formed. Another embodiment of the present invention is one in which the installation axes of the fixing parts for fixing the curved parts in between are parallel and offset, whereby the curved parts of the nozzle tube can be formed.

[0011]

The nozzle tube is connected to the nozzle at the nozzle tube connecting portion, and the nozzle tube is fixed. The nozzle tube on the side opposite to the nozzle with respect to the fixed position is curved, and the nozzle tube is further fixed by a fixing portion via a vibration damping material. As a result, the curved portion of the nozzle tube is sandwiched between the fixed portions, and the curved shape is maintained. The nozzle tube behind the curved portion and the fixed portion is connected to a mechanism for supplying ink, and the ink is supplied from the ink supply mechanism to the nozzle through the nozzle tube connection portion through the nozzle tube, the curved portion and the fixed portion, and recording is performed. The ink is ejected onto the medium and printing is performed. The vibration generated in the inkjet printer is transmitted from the fixed portion to the nozzle tube side, but the vibration is damped by the vibration damping material provided in the fixed portion, and the vibration to the nozzle tube is reduced. Further, the movement of the print head causes stress in the nozzle tube, but the stress is blocked by the fixed portion of the nozzle tube, and the stress transmitted to the curved portion through the fixed portion deforms the nozzle tube in the curved portion. The stress transmission to the nozzle tube connection can be eliminated.

Therefore, the vibration from the outside is blocked by the vibration damping material of the fixed portion, and the stress applied to the nozzle tube is restrained by the fixed portion and the curved portion absorbs the displacement, whereby the nozzle tube connecting portion is absorbed. Transmission to will be blocked.

Further, the tubular vibration damping portion of the fixed portion of the nozzle tube wraps the outer periphery of the nozzle tube, and the fixture holds and fixes the tubular vibration damping portion from the outside. The cylindrical vibration damping portion reduces the vibration transmitted to the nozzle tube provided inside thereof. Since the nozzle tube is fixed by the vibration damping part of the fixed part, the stress generated in the nozzle tube almost blocks the stress transmitted to the nozzle tube connection part by this fixing part, but the vibration damping part slips the nozzle tube connection The stress transmitted to the part remains. The curved portion of the nozzle tube formed by the fixed portion is displaced by the residual stress transmitted through the fixed portion. Therefore, the transmission of vibration and stress to the nozzle tube connecting portion is blocked, the influence of vibration and stress on the nozzle is reduced, and the print quality is improved.

When the fixing portions for fixing the nozzle tube are arranged so that the installation directions thereof intersect with each other, the nozzle tube sandwiched between the fixing portions becomes curved, and the absorbability of stress is improved. Further, when the fixing axes for fixing the nozzle tube are arranged parallel to each other and offset from each other, the nozzle tube sandwiched between the fixing sections is curved, and the stress absorbability is improved.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. (Structure of One Embodiment of the Present Invention) FIG. 1 is a perspective view showing an outline of a print head portion of an ink jet printer of the present invention, and FIG. 2 is a sectional view of a fixing portion of the ink jet printer of the present invention. 1A shows the state of the print head 1 in the print mode, and FIG. 1B shows the state of the print head 1 in the standby mode. The print mode is a case where the ink is ejected toward the recording medium (not shown) arranged at the lower position in the drawing to perform the printing, and the standby mode is the case where the nozzle 2 is used as the recording medium. This is a case where printing on a recording medium is not performed in different directions. In this standby mode, for example, the ejection state of the ink is inspected by ejecting the ink 21 other than the recording medium,
It is an adjustment.

The ink 21 is ejected through a nozzle hole 22 formed at the tip of the nozzle 2. As the nozzle 2, for example, in a piezo type ink jet printer, a print nozzle that is vibrated by a piezo (piezoelectric) element can be used. The print head frame 11 can be configured by, for example, a structure including a head support portion 12 for mounting the nozzle 2 and a nozzle tube support portion 13 for fixing the nozzle tube 3. In FIG. 1, the surface of the head support 12 and the nozzle tube support 13
The surface of the head support portion 12 and the surface of the nozzle tube support portion 13 may be flush with each other or parallel to each other.

A rotary shaft 14 is attached to the print head heme 11, and the rotation of the rotary shaft 14 causes the print head heme 11, the nozzle 2, and the nozzle tube 3 fixed to the nozzle tube support 13 to rotate. The rotary shaft 14 is a mechanism for changing the ink ejection direction of the nozzles 2, and has a print mode position as shown in FIG. 1A and a standby mode position as shown in FIG. Of at least two positions. The axial direction of the rotary shaft 14 is not limited to the direction orthogonal to the axial direction of the nozzle 2 as shown in FIG.
Any direction can be used as long as the ink ejection direction of the nozzle 2 is changed by the rotational movement of the nozzle 4.

The nozzle 2 is fixed to the head supporting portion 12 by any fixing means, and is fixed so that the position with respect to the head supporting portion 12 does not change even when the print head is displaced by the driving of the rotary shaft 14. The nozzle tube 31 is connected to the nozzle 2 at a nozzle tube connection portion 31, and the nozzle tube 3 extending from the nozzle tube connection portion 31 is connected to the nozzle tube support portion 13.
Is fixed to the print head frame 11. The fixing of the nozzle tube 3 to the nozzle tube supporting portion 13 is performed by the tube fixing portion 4 shown by the first tube fixing portion 41 and the second tube fixing portion 42 in FIG. 2A and 2B are cross-sectional views of the tube fixing portion 4. FIG. 2A shows a cross section orthogonal to the axial direction, and FIG. 2B shows a cross section in the axial direction.

The tube fixing portion 4 is provided with a vibration damping material 44 and a tube fixing member 43. The vibration damping member 44 has a hollow cylindrical shape that encloses the outer circumference of the nozzle tube 3, is a member that stores and holds the nozzle tube 3 in the hollow portion, and is made of a material such as rubber that absorbs vibration. be able to. The tube fixture 43 is a member that holds and fixes the vibration damping material 44 holding the nozzle tube 3 inside from the outside toward the print head frame 11 side, and is made of any material such as synthetic resin or metal. Can be formed. Any fixing means can be used to fix the tube fixing tool 43 to the print head frame 11. When the tube fixing tool 43 is fixed to the print head frame 11, the tube fixing tool 43 slightly presses the vibration damping material 44, and the nozzle tube 3 is held and fixed via the vibration damping material 44.

The vibration damping material 44 is used for the print head frame 1.
1 and the tube fixing tool 43, the vibration damping function of damping the vibration transmitted to the nozzle tube 3 side by damping the vibration transmitted through the nozzle fixing tool 43 and the nozzle tube 3 while allowing the axial displacement of the nozzle tube 3 to some extent. It has a holding function of holding. The diameter of the nozzle tube 3 is, for example,
In the case of about 1.2 mm, the length of the tube fixture 43 and the vibration damping material 44 can be about 5 mm, and the diameter of the vibration damping material 44 can be about 2.5 mm. This numerical value is an example, and this embodiment is not limited to this numerical value.

The first tube fixing portion 41 and the second tube fixing portion 42 are arranged, for example, on the nozzle tube supporting portion 12 so that their axial directions intersect with each other. At, the nozzle tube is made slack to form the nozzle tube curved portion 32. The arrangement of the first tube fixing portion 41 and the second tube fixing portion 42 can be configured such that the respective axial directions are parallel and offset, and the first tube fixing portion 41 and the second tube fixing portion 42 are sandwiched. Nozzle tube 3
Any arrangement can be applied that provides a slack in the to form a curve. The nozzle tube 3 extending from the second tube fixing portion 42 is connected to the filter side (not shown).

(Operation of Embodiment of the Present Invention) Next, the operation of the embodiment of the present invention will be described with reference to FIG. 3A and 3B are views for explaining the driving state of the print head 3, FIG. 3A is a schematic view seen from the axial direction of the rotary shaft, and FIG. 3B is FIG. 3A. FIG. 7B is a schematic view seen from the B direction and the C direction in FIG. In the print mode as shown in FIG. 1A, the rotary shaft 14 is rotated around the rotation center to direct the nozzles 2 of the print head 1 toward the recording medium. Facing downwards. Assuming that no stress is applied to the nozzle tube 3 at the position of the print head 1, the print head 1 is moved to the position B in FIG.
When viewed from the direction of, the nozzle tube 3 is not displaced by stress as shown in FIG. 3B, and the nozzle tube curved portion 32 is not displaced.

On the other hand, in the standby mode as shown in FIG. 1B, the rotary shaft 14 rotates around the center of rotation to direct the nozzles 2 of the print head 1 to the direction other than the recording medium. In FIG. 3 (a), it is oriented diagonally. At the position of the print head 1, the rotation of the print head 1 changes the positional relationship between the nozzle tube 3 and a portion (not shown) that fixes the nozzle tube 3 and stresses the nozzle tube 3. Is added.
This stress acts on the deforming portion 33 of FIG. 3A to deform the nozzle tube 3. Since the nozzle tube 3 is elastically fixed by the tube fixing portion 4 on the head support portion 12 and the nozzle tube support portion 13, the deformation of the nozzle tube 3 by the deformation portion 33 is hardly affected.

However, since the tube fixing portion 4 elastically supports and fixes the nozzle tube 3 by the vibration damping material 44, the nozzle tube 3 is deformed in the deforming portion 33.
When is deformed, the nozzle tube 3 will be displaced while sliding in contact with the vibration damping material 44. for that reason,
The displacement of the deforming portion 33 is transmitted to the nozzle tube bending portion 32 through the second tube fixing portion 42, and the nozzle tube 3 is deformed in the nozzle tube bending portion 32 to change the degree of the bending. As a result, the displacement of the deforming portion 33 is absorbed by the nozzle tube bending portion 32.
3C is a view seen from the direction C in FIG. 3A, and the deformation of the nozzle tube bending portion 32 is shown by the deformation portion 34. This nozzle tube bending part 3
The second deformation absorbs the deformation of the nozzle tube that has passed through the second tube fixing portion 42 and reduces the transmission to the nozzle tube connecting portion 31 side. The deformation of the nozzle tube 3 itself in the nozzle tube bending portion 32 is transmitted to the second tube fixing portion 42, but since the displacement is smaller than the deformation caused by the stress, it is almost the second deformation.
It is blocked by the tube fixing portion 42 and does not reach the nozzle tube connecting portion 31.

Therefore, the deformation of the nozzle tube 3 due to the rotation of the print head 1 is blocked by the first tube fixing portion 41, the deformation passing through the first tube fixing portion 41 is absorbed by the nozzle tube bending portion 32, and It is blocked by the second tube fixing portion 42 and hardly transmitted to the nozzle tube connecting portion 31, so that it is possible to prevent the print quality of the print head 1 from being affected. In the embodiment, the stress is not generated in the print mode, and the stress is generated in the standby mode as an example. However, this is for simplifying the description and is not always the same as the embodiment. However, the configuration of the present invention can be applied regardless of which stress is generated in which mode.

(Modification) In the above-mentioned embodiment, the fixed portions sandwiching the curved portion of the nozzle tube are arranged so that their installation axes intersect, but the installation axes are arranged in parallel and offset. Can also be Further, in the above-described embodiment, the first tube fixing portion and the nozzle are curved, but the first tube fixing portion and the nozzle may be linearly arranged.

(Effect of Embodiment) According to the embodiment, the print quality in the print mode and the print quality in the standby mode can be matched, and the print quality in the standby mode accurately corresponds to the print quality in the actual print mode. The print quality in the actual print mode can be sufficiently adjusted by adjusting the print quality in the standby mode.

[0028]

As described above, according to the present invention,
No stress is applied to the nozzle tube connection portion, and it is possible to provide an inkjet printer with good print quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a print head unit of an inkjet printer of the present invention.

FIG. 2 is a sectional view of a fixed portion of the inkjet printer of the present invention.

FIG. 3 is a diagram for explaining a drive state of a print head 3.

FIG. 4 is a conceptual diagram for explaining the configuration of an inkjet printer.

FIG. 5 is a schematic diagram for explaining a head used in a piezo type inkjet printer.

FIG. 6 is a conceptual diagram for explaining the operation of the inkjet printer.

FIG. 7 is a conceptual diagram for explaining the operation of a conventional print head.

[Explanation of symbols]

1 ... Print head, 2 ... Nozzle, 3 ... Nozzle tube, 4
… Tube fixing part, 11… Print head frame, 12…
Head support part, 13 ... Nozzle tube support part, 14 ... Rotation shaft, 21 ... Ink, 22 ... Nozzle hole, 31 ... Nozzle tube connection part, 32 ... Nozzle tube curved part, 41 ... First tube fixing part, 42 ... No. 2 tube fixing part, 43 ...
Tube fixing tool, 44 ... Vibration damping section.

Claims (1)

[Claims] 1. An ink jet printer comprising a print head having a nozzle and a nozzle tube connected to the nozzle, wherein a curved portion formed on the nozzle tube and the nozzle tube sandwiching the curved portion are provided with a vibration damping material interposed therebetween. An inkjet printer, comprising: a fixing unit that fixes the device by fixing it.