JP3126938U - Inkjet head cap device - Google Patents

Abstract

Provided is a cap device for an ink jet head that does not have poor adhesion to the head due to ink contamination even if ink discharged by pressure purge adheres to the cap.
A cap device according to the present invention is a cap that detachably contacts an ink discharge surface of an ink jet head 1 and covers the ink discharge surface. During normal printing, the cap is moved away from the head to a standby position. At the time of pressure purge, the cap 2 is inverted 180 ° at a position moved downward from the head so that the bottom surface of the cap 2 faces the discharge surface.
[Selection] Figure 1

Description

  The present invention relates to a cap device for protecting the ink discharge surface side of an ink jet head for a printer, and in particular, the cap can be prevented from being deteriorated due to contamination of the cap with the ink. The present invention relates to an inkjet head cap device.

  Some ink jet printers have a structure in which an ink ejection surface side where nozzles of an ink jet head are opened is protected by a cap. In this structure, when the ink is ejected, the cap is moved to the standby position, and when the ink is not ejected, the lower part of the head where the nozzle is opened is covered with the cap, so that the area around the nozzle of the head is sealed with the cap and the ink is dried. And nozzle clogging due to drying.

  8A and 8B show an ink jet head provided with a conventional cap device, and the lower surface of the head 1 having an ink chamber inside is an ejection surface having a plurality of ink ejection ports (nozzles) opened. Yes, black portions in the figure indicate ink that swells from the nozzles. Around the discharge surface, the upper surface side of the cap 2 having a concave cross section can come into contact with the discharge surface in a detachable manner. In general, the discharge port of this type of head 1 is kept at a negative pressure due to a water head difference from the supply ink tank, and ink does not drop inside the cap 2 when ink is not discharged.

  As shown in FIG. 8A, volatilization of the solvent contained in the ink is prevented by covering (capping) the lower periphery of the head 1 with the close contact of the cap 2 when the ink is not ejected. At the time of maintenance for preventing clogging of the discharge port or dealing with clogging of the discharge port, the ink is discharged from the discharge port by the pressure purge. At the time of this pressure purge, as shown in FIG. The discharged ink adhered to the upper surface side of the cap 2 that is in a lower position away from the head 1 and that contacts the ejection port of the head.

  However, the ejected ink is not necessarily ejected only into the recess 2a, but adheres to the periphery of the recess 2a that abuts the lower surface of the head and solidifies. In this state, the cap 2 is brought into contact with the head 1 again. In some cases, sufficient adhesion could not be obtained. In addition, if the head is capped with a cap that is soiled with ink, the contact portion of the head and cap is soiled with ink, and if the head and cap are left soiled with ink, the solvent content of the ink volatilizes and the head and cap In some cases, the contact portion of the cap is fixed.

  The present invention solves the above-described problems. The purpose of the present invention is to prevent the cap from being damaged due to dirt even if ink discharged by pressure purge adheres to the cap during maintenance or the like. An ink-jet head cap device is provided.

An ink jet head cap device according to claim 1,
In the cap device that covers the ink discharge surface by detachably contacting the contact surface of the cap around the ink discharge surface of the inkjet head,
During printing, the cap is moved away from the head and moved to a standby position, and during pressure purge, the cap is moved away from the head, and the bottom surface opposite to the contact surface faces the ink ejection surface. It is characterized by being rotated.

An ink-jet head cap device according to claim 2, wherein the ink-jet head cap device according to claim 1,
The bottom surface of the cap is inclined in a triangular shape in cross section.

An ink-jet head cap device according to claim 3 is the ink-jet head cap device according to claim 2,
Inclined end portions of the inclined surface protrude in a hook shape with respect to both side walls of the cap.

An ink-jet head cap device according to claim 4, wherein the ink-jet head cap device according to claim 1,
An ink reservoir having a concave cross section is formed on the bottom surface of the cap.

An ink-jet head cap device according to claim 5 is the ink-jet head cap device according to claim 4,
It is characterized in that hook-shaped convex portions are formed to protrude on both side walls of the cap.

  According to the first aspect of the present invention, the ink by the pressure purge adheres to the bottom surface of the cap, and the discharged ink does not adhere to the opening edge of the cap that contacts the nozzle surface of the head during capping. Further, it is possible to prevent the head from being soiled by capping the cap to which the ink is attached, and to maintain the sealing property at the time of capping.

  According to the second aspect of the invention, in addition to the operation and effect of the first aspect, the ink that has been discharged and adhered to the bottom surface side of the cap can flow down to both sides of the lower portion along the inclined surface.

  According to the third aspect of the invention, in addition to the effect of the second aspect, the ink discharged at the time of the pressure purge and flowing down to both sides of the lower part along the inclined surface of the cap is not easily transmitted to the contact surface side.

  According to the fourth aspect of the invention, in addition to the effect of the first aspect, the ink discharged during the pressure purge and transferred to the bottom surface side of the cap can be stored in the concave portion formed on the bottom side.

  According to the fifth aspect of the invention, in addition to the operation and effect of the fourth aspect, even if the ink discharged during the pressure purge and accumulated in the concave portion of the cap overflows, the outflowed ink is not easily transmitted to the contact surface side.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, with reference to FIGS. 6 and 7, an image forming apparatus 100 including an inkjet head 1 as a printing unit that can obtain a useful result by applying the cap device of the present invention will be described.

  As shown in FIG. 6, the image forming apparatus 100 includes upper and lower casings 101 and 102 as a main body. The upper casing 101 includes a belt conveyance unit 103 that is a conveyance unit that conveys the printing paper P in the horizontal direction. The belt conveying unit 103 is provided with a suction fan 105 that is a holding unit for the printing paper P along the lower surface of the upper portion that contacts the printing paper P on the moving endless belt 104. When the endless belt 104 includes a plurality of holes or a plurality of endless belts provided in parallel to each other, the suction fan 105 sucks the printing paper P through these gaps, thereby the endless belt 104. By holding the printing paper P on the belt 104 and moving the endless belt 104, the printing paper P can be conveyed without misalignment. Further, a paper feeding means 106 is provided on the entrance side of the belt conveying means 103, and the stacked printing paper P can be fed into the belt conveying means 103 one by one from the top. Further, printing means comprising four inkjet heads 1 arranged downward at an appropriate interval is provided above the upper portion of the endless belt 104 that contacts the printing paper P. The ink colors of each inkjet head 1 are black, cyan, magenta, and yellow along the conveyance direction of the printing paper P. In addition, a paper discharge unit 107 is provided on the exit side of the belt conveyance unit 103, and the printed printing paper P can be discharged onto a paper discharge table.

  As shown in FIG. 7, the roller of the belt conveying means 103 is provided with a rotary encoder 108 as a conveying position detecting means, and the control means 110 receiving the pulse signal S1 sends a timing signal S2 to each inkjet head 1 of the printing means. And the ink of each color can be ejected onto the printing paper P held and conveyed by the endless belt 104 by the belt conveying means 103 at an appropriate timing.

  The control means 110 performs color separation on the image to be formed and obtains drive data for each color inkjet head 1, and then the belt conveyance means 103 conveys the signal S 1 from the rotary encoder 108 as a reference. By driving each inkjet head 1 corresponding to the position of the printing paper P, the ink of each color is aligned and discharged at an appropriate position on the printing paper P, thereby printing a color image as the original image. It can be reproduced and formed on the paper P.

  In FIG. 6, a sheet conveyance path 111 for double-sided printing is arranged inside the upper casing 101 so as to cover the upper side of the printing unit. The paper conveyance path 111 is a conveyance path that connects the outlet side and the inlet side of the belt conveyance means 103, and a conveyance roller and a conveyance belt are arranged along the path so that the printing paper P can be conveyed. In the paper transport path 111, a switching unit 112 is provided in the vicinity of the exit side of the belt transport unit 103, and a switchback type paper reversing unit 114 is provided in the vicinity of the entrance side via another switching unit 113. ing.

  Therefore, when the printing paper P is printed on both sides, the printing paper P is printed on the surface while being conveyed by the belt conveyance means 103, and then is guided to the paper conveyance path 111 via the switching unit 112, and another switching unit. 113 is guided to the sheet reversing unit 114, and the other switching unit 113 is switched again and then introduced into the sheet conveying path 111 to return to the entrance of the belt conveying unit 103. Finally, the back surface is printed while being conveyed by the belt conveying unit 103. The paper can be discharged to the paper discharge means 107.

  In FIG. 6, second and third paper feeding units 106 ′ and 106 ″ are provided inside the lower housing 102, and the belt conveying unit 103 is different from the first paper feeding unit 106. The size of the printing paper P ′, P ″ can be supplied. Reference numeral 110 denotes the control means.

  Next, a specific configuration of the ink jet head part, which is a main part of the present invention, will be described with reference to FIGS. 1A and 1B are a front view and a cross-sectional view showing the first embodiment.

  In FIG. 1, the inkjet head 1 has a substantially rectangular shape, and a plurality of ink discharge ports (a black-painted portion in the drawing is a discharge port) along the width direction of the endless belt 104 that is the above-described sheet conveyance surface. The cap 2 is opened at a predetermined interval, and a cap 2 that is detachably contacted with the head 1 is disposed in the vicinity of the ink discharge surface that is the lower surface of the head 1.

  The cap 2 is made of a material having a predetermined elasticity, and a concave portion 2a is formed on the upper surface of the cap 2 so as to form a space portion with each discharge port when the cap 2 is in contact with the peripheral edge of the discharge surface of the head 1. The bottom surface is a rectangular flat surface 2b. The cap 2 is supported by a moving mechanism (not shown) and is connected to a reversing drive mechanism 4 such as a motor mounted on the moving mechanism.

  FIG. 1A shows the state of the head 1 during a non-printing operation. The cap 2 is located at the raised position, and the periphery of the recess 2a is in close contact with the periphery of the ejection surface of the head 1. As a result, the discharge port is hermetically covered, and ink evaporation and clogging of the discharge port due to the saturated vapor pressure formed in the sealed space in the recess 2a are prevented to a high degree. When the printing is stopped, the discharge port of the head 1 is kept at a negative pressure due to a water head difference from the ink tank for supply, and thus natural dripping to the concave portion 2a due to the weight of the ink or the like is generally prevented.

  During the printing operation, the cap 2 is lowered and separated from the lower surface of the head 1 by driving to the lower side by the moving mechanism, and further, in this state, the moving mechanism is retracted to a standby position where it does not interfere with the paper transport surface, and then printing is performed. Action is taken.

  On the other hand, in the pressure purge performed at the time of maintenance or the like, as shown in FIG. 1B, the cap 2 is lowered and separated from the head 1 to a predetermined separation position, and then reversed by 180 degrees by the reversing drive means 4. The bottom surface 2b, which is the bottom surface, is made to face the ejection surface of the head 1. In this state, pressure purge is executed, and ink is ejected from the ejection port and discharged to the bottom surface of the cap 2.

  After the pressurization purge is completed, the ink adhering surface is removed by wiping the ink discharge surface with a cleaning means (not shown) or the like to remove the ink and make it clean. Thereafter, the cap 2 is inverted 180 ° again by driving of the inversion driving means 4, and is lifted by driving of the moving mechanism to be brought into close contact with the ejection surface of the head 1 again.

  Note that the pressure purge operation at the time of maintenance described above may be periodically executed every time the timer expires when the state where the head 1 is closed with the cap 2 continues for a predetermined time. However, it may be executed every time the power is turned on.

  FIG. 2 shows a second embodiment. In FIG. 2, the point that the bottom surface portion of the cap 2 has a triangular cross section and has inclined surfaces 2c on both sides is different from the first embodiment, and other configurations are the same as those of the first embodiment. is there.

  In the above configuration, at the time of pressure purge, ink is discharged from the ejection port of the head 1 to a triangular ridgeline, distributed to the left and right with the ridgeline as a boundary, and flows down along the respective inclined surfaces 2c. In the present embodiment, compared to the first embodiment, the amount by which the ejected ink bounces back to the head 1 is even smaller than when the bottom surface is a flat surface.

  FIG. 3 shows a third embodiment which is a further development of the second embodiment. In FIG. 3, the second embodiment, except that the lower edge (inclined end portion) of the inclined surface 2 c is integrally formed with a flange-like protruding portion 2 d that protrudes from both side walls of the cap 2. It is the same. In the present embodiment, since the overhang portion 2d is provided, it is possible to prevent the ink from flowing from the side wall to the contact surface, so that the stain prevention effect is further enhanced.

  FIG. 4 shows a fourth embodiment of the invention. In FIG. 4, the bottom of the cap 2 is the same as that of the first embodiment except that a recess 2e is formed as an ink reservoir that is slightly deeper than the recess 2a.

  In the present embodiment, the ink discharged during the pressure purge is accumulated in the recess 2e. Since the amount of ink discharged per pressurizing purge is small, the inside of the recess 2e is not immediately filled with ink, and is maintained in an always usable state by regular maintenance.

  FIG. 5 shows a fifth embodiment which is a further development of the fourth embodiment. The present embodiment is the same as the fourth embodiment, except that hook-shaped convex portions 2f that incline toward the upper side on the both sides of the cap 2 (the opposite is the case when upside down) project. In this embodiment, the ink overflowing to the outside of the recess 2e flows down the side wall, is guided to the projection 2f, and falls at a position away from the main body side wall of the cap 2. Therefore, as in the example shown in FIG. Is prevented from going from the side wall to the abutting surface, so that the effect of preventing dirt is further enhanced.

(A), (b) is the front and cross-sectional explanatory drawing of the cap by 1st Embodiment of this invention. It is a section explanatory view showing the second embodiment. It is a section explanatory view showing the 3rd embodiment. It is a section explanatory view showing the 4th embodiment. It is a cross-sectional explanatory view showing the fifth embodiment. 1 is a schematic configuration diagram of an image forming apparatus to which the above embodiment can be applied. FIG. 2 is a schematic enlarged perspective view of the vicinity of a printing unit of the image forming apparatus. (A), (b) is the front and sectional explanatory drawing of the conventional cap apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Cap 2a Concave part 2b Bottom face 2c Inclined surface which is a triangular inclination 2d The ridge part projected in the ridge shape 2e The recessed part 2f convex part as an ink reservoir

Claims (5)

In the cap device that covers the ink discharge surface by detachably contacting the contact surface of the cap around the ink discharge surface of the inkjet head,
During printing, the cap is moved away from the head and moved to a standby position, and during pressure purge, the cap is moved away from the head, and the bottom surface opposite to the contact surface faces the ink ejection surface. An inkjet head cap device, wherein the inkjet head cap device is rotated. 2. The ink jet head cap device according to claim 1, wherein the bottom surface of the cap is inclined in a triangular cross section. The inkjet head cap device according to claim 2, wherein the inclined end portions of the inclined surface project in a hook shape with respect to both side walls of the cap. 2. The ink jet head cap device according to claim 1, wherein an ink reservoir having a concave cross section is formed on the bottom surface of the cap. The inkjet head cap device according to claim 4, wherein hook-shaped protrusions are formed to protrude on both side walls of the cap.

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