KR20070021427A - Inkjet image forming apparatus comprising cleaning unit - Google Patents

Abstract

An ink jet image forming apparatus having a cleaning unit is disclosed. An inkjet image forming apparatus having the disclosed cleaning unit includes: a print head having a nozzle portion of a length corresponding to a width of a print medium; A moving block moved in a direction in which the print medium is transferred; Cleaning the waste ink in contact with the nozzle portion while being arranged and moved in the longitudinal direction of the nozzle portion, the plurality of blades having an overlapping portion at the end for overlapping the cleaning of the nozzle portion; It is mounted on the moving block, comprising a cleaning unit having a plurality of blades, wherein the overlap portion is characterized in that it is formed in a shape different from other parts of the blade to clean the nozzle portion with a weak contact force.

The present invention can prevent the nozzle portion from being damaged or worn by the cleaning unit by configuring a part of the cleaning unit that cleans the nozzle portion so as to be different from the other portions, unlike the conventional invention. That is, by cleaning the nozzle unit with a weak contact force in the cleaning unit, the life of the nozzle unit and the blade provided in the head chip can be improved. In addition, this improves the cleaning function of the nozzle unit, which is one of the maintenance functions, to improve the print quality.

Description

An inkjet image forming apparatus having a cleaning unit.

1 is a view showing a print head and a wiping blade provided in an ink cartridge of a conventional inkjet image forming apparatus.

FIG. 2 is an enlarged view of a contact portion between the print head and the wiping blade illustrated in FIG. 1.

3 is a view schematically showing an embodiment of an inkjet image forming apparatus according to the present invention.

4 is a bottom view showing one embodiment of a print head according to the present invention.

5 is a perspective view showing the configuration of the cleaning apparatus according to the present invention.

FIG. 6 is a cross-sectional view taken along line II ′ of FIG. 5.

7 is a perspective view illustrating one embodiment of a cleaning unit.

8 is a perspective view showing another embodiment of the cleaning unit.

9 is a bottom view showing a part of the cleaning unit and the nozzle unit of the present invention.

<Description of the symbols for the main parts of the drawings>

101 .......... Ink section 105 .......... Print head unit

106 .......... carriage 110 .......... body

111 .......... Print head 112 .......... Nozzle section

113, 115, 116, 117 ....... Print media transport

114 ........ Support member 130 .......... Control section

132 ........ Defective nozzle detection unit 140 ..........

200 .......... Cleaning device 230 .......... Drive

240 .......... Moving block 250 .......... Cleaning unit

255 .......... blade 256 .......... the other part of the blade

257 .......... overlay of blade

The present invention relates to an inkjet image forming apparatus, and more particularly, to a cleaning unit for cleaning a nozzle face of a print head of a length corresponding to a width of a print medium.

An inkjet image forming apparatus is an apparatus for forming an image by spraying ink onto a printing medium. The inkjet image forming apparatus is classified into a shuttle method and a line printing method according to a printing method. The shuttle type inkjet image forming apparatus prints by using a print head reciprocated in a direction perpendicular to the transfer direction of the print medium, and the line printing type inkjet image forming apparatus includes a print head having a nozzle portion having a length corresponding to the width of the print medium. To print.

In general, a print head uses thermal energy, a piezoelectric element, or the like as an ink jet power source, and is manufactured to have high resolution by a semiconductor manufacturing process such as etching, deposition, and sputtering, and the ink is transferred to a print medium from a nozzle unit provided in the print head. Spray to print an image. After the ink is ejected from the nozzle portion, if the amount of waste ink remaining on the surface is increased, the print quality is deteriorated, such as bending the path of the ink droplets. In order to solve this problem, a cleaning unit is provided to wipe off waste ink remaining on the surface of the nozzle unit.

1 is a view illustrating a print head and a wiping blade provided in an ink cartridge of a conventional inkjet image forming apparatus, and FIG. 2 is an enlarged view of a contact portion between the print head and the wiping blade illustrated in FIG. 1.

1 and 2, the lower end of the ink cartridge 20 mounted on the carrier 10 is provided with a print head 30 having a plurality of nozzles (not shown) for ejecting ink droplets. By the way, the nozzle surface 32 of the print head 30 is liable to be ink or foreign matter discharged from the nozzle, it is necessary to clean the nozzle surface 32 of the print head 30 accordingly. To this end, the inkjet image forming apparatus is provided with a wiping blade 40 for cleaning the nozzle face 32 of the print head 30. The wiping blade 40 is supported by the holder 50 and installed to reciprocate. When the wiping blade 40 moves in the direction of arrow A, the tip of the wiping blade 40 comes into contact with the nozzle face 32 of the print head 30 in a slightly curved state. In this state, the wiping blade 40 continuously moves in the direction of the arrow A to remove ink or foreign matter on the nozzle surface 32.

The hydrophobic coating film 34 is generally formed on the nozzle face 32 of the print head 30 so that ink or the like is not easily adhered to. However, if the cleaning operation on the nozzle face 32 of the print head 30 by the wiping blade 40 is repeated, the hydrophobic coating film (B) may be caused by repeated friction between the wiping blade 40 and the nozzle face 32. 34) gradually become damaged and lose its characteristics. In this case, the nozzle face 32 of the print head 30 is easily contaminated by waste ink or the like, which causes a problem of lowering print quality. Therefore, the conventional wiping blade 40 has a problem in that the hydrophobic coating film 34 formed on the nozzle face 32 is easily worn to lower its durability.

On the other hand, in the line printing type print head, the nozzle portion to be cleaned has a length corresponding to the width of the print medium. Therefore, when it is cleaned using one wiping blade, it is impossible to uniformly clean the waste ink remaining in the nozzle unit.

In order to solve the above problems, the waste ink remaining in the nozzle unit may be cleaned by dividing the wiping blade into several pieces. In order to uniformly clean the nozzle portion, the wiping blade should be installed so as to overlap and clean a predetermined area. That is, each nozzle portion is provided with an area to be cleaned to be overlapped by the wiping blade. As such, when the nozzle parts are overlapped and cleaned, not only the wear of the wiping blade is increased, but also the wear of the nozzle parts to be overlapped is increased, thereby reducing the life of the wiping blade and the life of the nozzle part. In addition, the cleaning function is degraded due to the wear of the wiping blade, so the print quality is also degraded. Therefore, there is a need for improvement.

SUMMARY OF THE INVENTION The present invention has been made to improve the above-mentioned problems, and an inkjet image forming apparatus which can prevent the life of each component from being shortened by adjusting a force applied to an area that is overlapped by the wiping blade. The purpose is to provide.

An inkjet image forming apparatus according to the present invention comprises: a print head having a nozzle portion having a length corresponding to a width of a print medium; A moving block moved in a direction in which the print medium is conveyed; Drive means for reciprocating the moving block; A plurality of blades having an overlapping portion at an end portion for cleaning the waste ink in contact with the nozzle portion while being arranged and moving in the longitudinal direction of the nozzle portion to overlap the nozzle portion; And a cleaning unit having the plurality of blades, wherein the overlapping portion is formed in a shape different from other portions of the blades so as to clean the nozzle portion with a weak contact force.

In one embodiment, the overlapping portion, characterized in that the width of the cross section is formed differently from the other portion of the blade so that the contact force applied to the nozzle portion is weaker than the other portion of the blade.

In one embodiment, a groove having a predetermined depth is formed between the overlapping portion and another portion of the blade.

In one embodiment, the print head is characterized in that n head chips having a plurality of nozzle rows are arranged in a zigzag in the longitudinal direction of the nozzle portion.

In an embodiment, the cleaning unit may include n blades corresponding to the n head chips.

Hereinafter, an inkjet image forming apparatus including a cleaning unit according to the present invention will be described in detail with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or convention of a user or an operator. Therefore, definitions of these terms should be made based on the contents throughout the specification.

3 is a view schematically showing an embodiment of an inkjet image forming apparatus according to the present invention. Hereinafter, for the convenience of description, the same reference numerals are used for components having the same configuration and operation.

Referring to FIG. 3, the inkjet image forming apparatus 125 may include a paper feed cassette 120, a print head unit 105, a support member 114 positioned to face the nozzle, and a defective nozzle of the nozzle unit 112. Defective nozzle detection unit 132 for detecting whether or not, the print medium transfer unit 117, 116, 115, 113 for transferring the print medium (P) in the first direction (x direction), and the print medium (P) is discharged And a cleaning device (not shown) for cleaning the waste ink remaining in the nozzle part 112 and the loading part 140 to be loaded later. In addition, the inkjet image forming apparatus 125 includes a controller 130 that controls the operation of each component.

The print medium P is loaded in the paper feed cassette 120. The print medium P loaded in the paper feed cassette 120 is transferred to the stacking unit 140 through the print head 111 by the print medium transporting units 117, 116, 115, and 113 described later. Here, the stacking unit 140 refers to a portion where the print medium P on which an image is formed, such as a discharge tray, is loaded after discharge.

The print media transport unit 117, 116, 115, 113 transports the print media P loaded in the paper feed cassette 120 along a predetermined path. In this embodiment, the pickup roller 117 and the auxiliary roller ( 116, the feeding roller 115, and the discharge roller 113. The print medium conveying units 117, 116, 115, and 113 are driven by a driving source 131 such as a motor, and provide a conveying force for conveying the print medium P. The operation of the driving source 131 is controlled by the controller 130 to be described later.

The pickup roller 117 is installed at one side of the paper feed cassette 120 and picks up and pulls out the print media P loaded on the paper feed cassette 120 one by one. The feeding roller 115 is installed at the inlet side of the print head 111 and transfers the print medium P drawn by the pickup roller 117 to the print head 111. The feeding roller 115 includes a driving roller 115A that provides a conveying force for transferring the print medium P, and an idle roller 115B that is elastically engaged thereto. Between the pickup roller 117 and the feeding roller 115, a pair of auxiliary rollers 116 for transferring the print medium (P) may be further installed. The discharge roller 113 is installed at the exit side of the print head 111 and discharges the print medium P on which the printing is completed out of the image forming apparatus 125. The print medium P discharged from the image forming apparatus 125 is loaded on the stacking unit 140.

In one embodiment, the discharge roller 113 is a star wheel 113A which is installed side by side in the width direction of the print medium (P), and the support roller 113B facing the support roller 113B to support the back surface of the print medium (P). Equipped. Star wheel 113A is a print medium (P) which is transported below the nozzle unit 112 is in contact with the nozzle 112 or the bottom of the body 110 or the gap between the print medium (P) and the nozzle unit 112 In order to prevent the change, at least a portion is installed to protrude more than the nozzle unit 112 is in point contact with the upper surface of the printing medium (P).

The support member 114 supports the rear surface of the print medium P provided and transported below the print head 111 so that the nozzle unit 112 and the print medium P maintain a predetermined interval. The distance between the nozzle portion 112 and the print medium P is about 0.5 to 2.5 mm.

The bad nozzle detection unit 132 detects a bad nozzle generated in the manufacturing process or a bad nozzle generated during a print job. A missing nozzle means a nozzle that does not normally eject ink, such as a dead nozzle or a weak nozzle that does not eject ink.

The bad nozzle detector 132 includes a first bad nozzle detector 132A and a second bad nozzle detector 132B. The first defective nozzle detecting unit 132A detects whether the nozzle hole is blocked when the print head 111 is mounted or by irradiating light to the nozzle unit 112 while the print head 111 is mounted. The second bad nozzle detector 132B detects whether a bad nozzle is generated by irradiating light onto the transferred print medium P. FIG.

In an embodiment, the bad nozzle detecting unit 132 includes an optical sensor. The optical sensor includes a light emitting sensor (for example, a light emitting diode) for irradiating light to the printing medium (P), and a light receiving sensor for receiving light reflected from the printing medium (P). The output signal from the light receiving sensor is input to the second bad nozzle detection unit 132B. The second bad nozzle detection unit 132B detects whether or not a bad nozzle is generated by the output signal, and information on whether or not a bad nozzle is generated is stored in a separate memory (not shown), and then the controller 130 is described later. Delivered. The construction and operation of the optical sensor itself are well known to those skilled in the art to which the present invention pertains, and thus a detailed description thereof will be omitted.

The control unit 130 is provided on the motherboard of the image forming apparatus 125, and the print head 111 according to whether a bad nozzle occurs, the type of the printing medium P, or the printing mode. Control the injection operation of the nozzle unit 112 and the transfer operation of the print medium transfer unit 113, 115, 116, 117. That is, the controller 130 detects the defective nozzle by the defective nozzle detecting unit 132, or the ink sprayed from the nozzle unit 112 according to the type or printing mode of the printing medium P is applied to the printing medium ( Synchronize the operation of each component to reach the desired area of P).

The print head unit 105 prints an image by spraying ink onto a print medium P, and includes a body 110, a print head 111 provided on one side of the body 110, and a print head 111. It is provided with a nozzle unit 112, and a carriage 106 to which the body 110 is mounted. The feeding roller 115 is installed at the inlet side of the nozzle unit 112, and the discharge roller 113 is rotatably installed at the outlet side. On the other hand, the print head 111 may be installed in a frame (not shown) provided in the print head unit 105.

4 is a bottom view showing one embodiment of a print head according to the present invention.

Referring to FIG. 4, the print head 111 is installed in a second direction (y direction) with respect to the print medium P conveyed in the first direction (x direction). The print head 111 uses thermal energy and a piezoelectric element as an ink jet power source, and is manufactured to have high resolution by semiconductor manufacturing processes such as etching, deposition, and sputtering. The print head 111 is provided with a nozzle unit 112 for forming an image by spraying ink onto the transferred print medium P. FIG. The nozzle unit 112 may have a length corresponding to the width of the print medium P, or may be formed longer than the width of the print medium P.

In one embodiment, the print head 111 is provided with a plurality of head chips H formed with a plurality of nozzle rows 112C, 112M, 112Y, and 112K. Each head chip H is provided with a driving circuit 112D for selectively driving each nozzle or driving each nozzle in group units. When the plurality of head chips H are arranged in a line, the nozzle spacing between the head chips H, which is the boundary portion, is further separated from the nozzle spacing in the same head chip H, so that the ink on the print medium P An area in which is not injected may be generated. Therefore, the plurality of head chips H is preferably arranged in a zigzag as shown. In addition, nozzle rows for injecting ink of the same color among the nozzle rows 112C, 112M, 112Y, and 112K of each head chip H are alternately arranged to improve resolution in the second direction (y direction). desirable. When the nozzle rows are arranged as described above, the ink dots sprayed from the nozzles of the nozzle rows are impacted between the ink dots sprayed from the nozzles of the other nozzle rows, thereby improving the resolution in the second direction (y direction).

 In the present embodiment, the print head 111 having the nozzle unit 112 composed of a plurality of head chips H is described as an example, but the nozzle unit 112 of the present invention may be configured in various forms. For example, each head chip H may be manufactured as one chip corresponding to the length of the print head 111, that is, the length corresponding to the width of the print medium P. Alternatively, the print head 111 may include a nozzle unit having a nozzle array having a length corresponding to the width of the print medium P. That is, the nozzle part 112 of the illustrated print head 111 is only an embodiment of the present invention, and the technical scope of the present invention is not limited by the configuration of the nozzle part 112 shown.

Each of the nozzles of the nozzle unit 112 is connected to a drive circuit 112D and a cable 112C to which a driving signal from the controller 130 to be described later, power for ink injection, image data, and the like are transmitted. As the cable 112C, a flexible cable such as FPC (Flexible Printed Circuit) or FFC (Flexible Flat Cable) is preferably used.

Although not shown, the body 110 has driving means (for example, piezoelectric piezoelectric elements and heat driven heaters) in communication with the nozzles of the nozzle unit 112 and providing pressure for ejecting ink. A chamber provided therein, a flow path (for example, an orifice) for supplying the ink contained in the body 110 to the chamber, a manifold which is a common flow path for supplying ink introduced through the flow path, and a manifold Restrictors and the like, which are separate flow paths for supplying ink to the respective chambers, may be further provided. Chambers, flow paths, manifolds, restrictors, etc. are well known to those skilled in the art to which the present invention pertains, and thus detailed description thereof will be omitted. On the other hand, the ink containing portion in which the ink is accommodated may be provided separately from the print head unit 105. The ink contained in the separately provided ink container is supplied to the print head unit 105 through an ink supply device (for example, a flow path) not shown. As described above, the ink stored in the ink receiving unit may be supplied to the print head from the ink receiving unit mounted on the print head unit through the ink supply unit, and printed through the ink supply unit from the ink receiving unit provided separately from the print head unit. It can also be supplied to the head. Since the configuration and operation of the print head unit itself is well known to those skilled in the art to which the present invention pertains, a detailed description thereof will be omitted.

5 is a perspective view illustrating a configuration of a cleaning apparatus according to the present invention, and FIG. 6 is a cross-sectional view taken along line II ′ of FIG. 5. 7 is a perspective view illustrating one embodiment of a cleaning unit, and FIG. 8 is a perspective view illustrating another embodiment of a cleaning unit.

5 and 6, the cleaning apparatus 200 includes a driving means 230, a moving block 240, and a cleaning unit 250.

The driving means 230 is supported by the driving motor 233 for forward and reverse rotation, the pulley 231 rotated by the driving motor 233, and the pulley 231 in the first direction (x direction). The belt 232 is circulated.

The moving block 240 is installed to be movable in the first direction, which is the direction in which the print medium is transferred. The moving block 240 is connected to the belt 232, and when the driving motor 233 is rotated, the moving block 240 is moved in the first direction. At this time, the guide surface 241 provided on one side of the moving block 240 is supported by the rail 261 provided in the housing 260 to guide the moving path of the moving block 240. By this configuration, the moving block 240 is reciprocated in conjunction with the forward and reverse rotation of the drive motor 233. In this embodiment, the driving force from the driving motor 233 is transmitted to the moving block 240 through the belt 232, but this is only one embodiment of the present invention, the technical scope of the present invention by the illustrated embodiment is limited It doesn't happen. For example, the driving force from the drive motor 233 may be transmitted to the moving block 240 through the gear coupling.

The cleaning unit 250 is mounted on the moving block 240, and the ink droplets, solid precipitates, and fine dusts, etc., deposited on the nozzle unit 112 while contacting the nozzle unit 112 at a predetermined pressure (hereinafter, “waste”). A plurality of blades 255 for cleaning (wiping).

The blade 255 is arranged in the second direction (y direction), which is the length direction of the nozzle part 112, and remains in the nozzle part 112 in contact with the nozzle part 112 at a predetermined pressure when the moving block 240 moves. Clean the waste ink. The blades 255 are alternately arranged in the second direction as shown. In order to cleanly remove the waste ink remaining in the nozzle unit 112, each of the blades 255 preferably cleans the nozzle unit 112 in a predetermined area. That is, as shown in FIG. 7, the blade 255 preferably includes an overlapping part 257 for cleaning the nozzle part 112 so as to overlap one end or both ends thereof.

Referring to FIG. 7, the overlapping part 257 formed at the end of the blade 255 cleans the nozzle part 112 to overlap. Since the nozzle unit 112 may be damaged when the nozzle unit 112 is overlapped, the overlap unit 257 is preferably configured to clean the nozzle unit 112 with a weak contact force. The overlap 257 is preferably formed in a different shape than the other portion 256 of the blade so as to clean the nozzle portion 112 with a weaker contact force than the other portion 256 of the blade.

In one embodiment, the overlap 257 has a cross-sectional width W2 such that the contact force exerted on the nozzle 112 by the overlap 257 is weak compared to the other portions 256 of the blade. It is preferred that it is formed differently from portion 256. That is, the thickness W2 of the overlapping portion 257 is preferably formed to be thinner than the thickness W1 of the other portion 256 of the blade.

In another embodiment, the overlap between the overlap 257 and the blade, as shown in FIG. 8, such that the contact force exerted on the nozzle portion 112 by the overlap 257 is weak compared to the other portions 256 of the blade. Preferably, grooves 258 of a predetermined depth are formed between the portions 256. At this time, the depth of the groove 258 is preferably formed so that the overlap portion 257 can be bent more easily than the other portion 256 of the blade.

9 is a bottom view showing a part of the cleaning unit and the nozzle unit of the present invention.

As described above, n head chips H having a plurality of nozzle rows are arranged in the print head 111 in a zigzag form in the longitudinal direction (y direction) of the nozzle unit 112. In order to clean the n head chips H, the cleaning unit 250 may include n blades 255 corresponding to the n head chips H. That is, as shown in FIG. 9, the cleaning unit 250 performs n blades 255 corresponding to n head chips H so that one blade 255 cleans one head chip H. It is preferable to provide. For example, if the number of the head chips H is 14, it is preferable that the number of the blades 255 for cleaning the head chips H is also 14.

As an example, each head chip H may include a main nozzle part 112M for printing an image by spraying ink upon printing, and an auxiliary nozzle part for compensating for some of the nozzles of the main nozzle part 112M being damaged. Dummy nozzle part 112D is provided. At this time, the main nozzle portion 112M for printing the printed image is cleaned by the other portion 256 of the blade as described above, and the auxiliary nozzle portion 112D is cleaned by the overlapping portion 257 of the blade.

According to the configuration as described above, the present invention is different from the conventional invention by configuring the shape of the overlapping portion 257 of the blade different from the shape of the other portion 256 of the blade, thereby to the blade 255 of the nozzle portion 112 It is possible to reduce the contact force applied to the portions to be superposedly cleaned.

As described above, the inkjet image forming apparatus according to the present invention, unlike the conventional invention, configures a part of the cleaning unit that cleans the nozzle part differently from other parts, thereby preventing the nozzle part from being damaged or worn by the cleaning unit. Can be. That is, by cleaning the nozzle unit with a weak contact force in the cleaning unit, the life of the nozzle unit and the blade provided in the head chip can be improved. In addition, this improves the cleaning function of the nozzle unit, which is one of the maintenance functions, to improve the print quality.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art to which the art belongs can make various modifications and other equivalent embodiments therefrom. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the claims below.

Claims (5)

A print head having a nozzle part having a length corresponding to a width of a print medium; A moving block moved in a direction in which the print medium is conveyed; Drive means for reciprocating the moving block; A plurality of blades having an overlapping portion at an end portion for cleaning the waste ink in contact with the nozzle portion while being arranged and moving in the longitudinal direction of the nozzle portion to overlap the nozzle portion; And Mounted on the moving block, the cleaning unit including the plurality of blades; And the overlapping portion is formed in a shape different from other portions of the blade so as to clean the nozzle portion with a weak contact force. The method of claim 1, wherein the overlapping portion, And the width of the cross section is formed differently from other portions of the blade such that the contact force applied to the nozzle portion is weaker than that of the other portions of the blade. The method of claim 1, And a groove having a predetermined depth is formed between the overlapping portion and another portion of the blade. The method according to any one of claims 1 to 3, And n head chips in which a plurality of nozzle rows are formed in the print head are arranged in a zigzag in the longitudinal direction of the nozzle portion. The method of claim 4, wherein the cleaning unit, And n blades corresponding to the n head chips.

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