KR20070012993A - Inkjet image forming apparatus comprising cleaning unit - Google Patents

Abstract

An ink-jet image forming apparatus including a cleaning unit is provided to improve the print quality by improving the cleaning function of a nozzle section. An ink-jet image forming apparatus includes a print head, a plurality of head chips, and a plurality of cleaning units(200). The print head includes a nozzle section having a length corresponding to the width of a print medium. The cleaning unit includes a drive shaft and a wiping blade. The wiping blade is installed in the drive shaft so as to be rotated on the same plane as the surface of the head chip. The wiping blade cleans wasted ink by making contact with the head chip. The number of the cleaning units is the same as the number of the head chips so that one cleaning unit can clean only one head chip.

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 view for explaining the configuration of the cleaning unit according to the present invention.

6 is a perspective view showing an embodiment of a cleaning unit according to the present invention.

7 is a view showing an example of the operation of the cleaning unit according to 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 Unit 210 .......... Drive Shaft

220 ........ wiping blade 223 .......... blade

230 .......... Moving Source

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, vapor deposition, and sputtering. Spray to print the 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, etc., which are deposited 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 may be caused by repeated friction between the wiping blade 40 and the nozzle face 32. (34) is gradually damaged and loses its character. 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, since the cleaning function is degraded due to the wear of the wiping blade, the print quality is also degraded. Therefore, there is a need for improvement.

An object of the present invention is to provide an inkjet image forming apparatus having a cleaning unit which can be prevented from generating an area that is overlapped by a wiping blade. .

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 plurality of head chips provided in the print head in a length direction of the nozzle part and having a plurality of nozzle rows; And a plurality of cleaning units having a driving shaft rotated in a predetermined direction and a wiping blade which is installed on the driving shaft so as to rotate on the same plane as the face of the head chip and contacts the head chip to clean the waste ink. And the same number of cleaning units as the number of the head chips so that the cleaning unit cleans only one head chip.

In one embodiment, the drive shaft is preferably installed in a direction orthogonal to the head chip surface.

In an embodiment, the wiping blade may be configured to clean the head chip while reciprocating at a predetermined angle while drawing a fan shape.

In an embodiment, the plurality of cleaning units may be alternately installed at both sides of the print head such that each wiping blade does not interfere with each other when cleaning the head chip.

In one embodiment, the plurality of head chips are preferably arranged in a zigzag.

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.

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 It is equipped with a loading unit 140 to be loaded after. 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. Hereinafter, for the convenience of description, the same reference numerals are used for components having the same configuration and operation.

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 transported printing medium P. 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. By arranging the nozzle rows as described above, the ink dots jetted from the nozzles of the nozzle rows are impacted between the ink dots jetted from the nozzles of the other nozzle rows, thereby improving the resolution in the second direction (y direction). The nozzle unit 112 of the illustrated print head 111 is only one embodiment of the present invention, and the technical scope of the present invention is not limited by the configuration of the nozzle unit 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 descriptions 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 view for explaining the configuration of the cleaning unit according to the present invention, Figure 6 is a perspective view showing an embodiment of a cleaning unit according to the present invention. 7 is a view showing an example of the operation of the cleaning unit according to the present invention.

5 and 6, the cleaning unit 200 is installed on the drive shaft 210 and the drive shaft 210 rotated in a predetermined direction, and contacts the head chip H to clean the waste ink ( A wiping blade 220).

As shown in FIG. 6, a pinion gear 212 is provided at one side of the drive shaft 210. The pinion gear 212 is engaged to engage the drive gear 232 driven by the drive source 230. Therefore, the driving force by the drive source 230 is transmitted to the pinion gear 212 via the drive gear 232, the drive shaft 210 coupled to the pinion gear 212 is rotated in a predetermined direction. When the drive shaft 210 is rotated as described above, the wiping blade 220 coupled to the drive shaft 210 is rotated to clean the waste ink remaining on the head chip (H). It is preferable to use a drive motor capable of forward and reverse rotation as the drive source 230. In this embodiment, the driving force from the drive source 230 is transmitted to the drive shaft 210 through the gear coupling, but this is only one embodiment of the present invention, the technical scope of the present invention is not limited by the illustrated embodiment. For example, the driving source 230 and the driving shaft 210 may be connected by a belt.

The wiping blade 220 is inserted into and coupled to the drive shaft 210 and wipes the waste ink remaining on the head chip H surface while being constrained by the movement of the drive shaft 210 and rotating in a predetermined direction. The wiping blade 220 is provided with a blade 223 having a coupling hole 222 into which the drive shaft 210 is inserted and coupled, and a contact portion 224 contacting the head chip H. The wiping blade 220 rotates on the same plane as the contact portion 224 of the blade 223 on the head chip H surface so that the contact portion 224 can wipe off the waste ink remaining on the head chip H. It is installed as possible. That is, the wiping blade 220 is installed so that the contact portion 224 contacts the head chip H at a predetermined pressure when the driving shaft 210 rotates to wipe off the waste ink. Therefore, it is preferable that the drive shaft 210 is provided in the direction orthogonal to the head chip H surface.

In addition, the blade 223 is preferably installed to clean only one head chip (H) during the rotation of the drive shaft 210 as shown in FIG. For example, the wiping blade 220 is preferably installed so that only one head chip H enters the rotation radius of the blade 223. That is, the wiping blade 220 is preferably installed so that the movement trajectory of the blade 223 does not interfere with another adjacent head chip H when cleaning one head chip H.

As described above, the cleaning unit 200 is installed to clean only one head chip H. Therefore, the present invention preferably includes the same number of cleaning units 200 as the plurality of head chips H. For example, if the number of the head chips H is 14, it is preferable that the number of the cleaning units 200 for cleaning the head chips H is also 14.

In one embodiment, the wiping blade 220 preferably includes at least one blade 223. The wiping blade 220 of this embodiment has two blades 223. The illustrated wiping blade 220 is only an embodiment of the present invention, and the technical scope of the present invention is not limited by the configuration of the illustrated wiping blade 220. For example, the wiping blade 220 of the present invention is one blade installed in the form of a "1", three blades each installed at an angle of 120 degrees, or four blades installed at an angle of 90 degrees each. It may be provided.

In addition, the wiping blade 220 may be rotated 360 degrees as shown in FIG. 5 to clean the head chip H, and as shown in FIG. 7, the wiping blade 220 may be reciprocated at a predetermined angle while drawing a fan-shaped trace. The chip H may be cleaned. Of course, in order to clean the head chip H while drawing the fan trace between the position shown by the solid line and the position shown by the dotted line, as shown in FIG. 7, a driving source 230 rotatable in the forward and reverse directions should be provided.

According to the configuration as described above, the present invention can clean the nozzle portion of the length corresponding to the length of the print medium while rotating the cleaning blade around the drive shaft, unlike the conventional invention.

As described above, in the inkjet image forming apparatus having the cleaning unit according to the present invention, unlike the conventional invention, the cleaning unit cleans only the head chip, so that the nozzle unit provided in the adjacent head chip cleans the other head chip. Can be prevented from being damaged or worn. That is, the life of the nozzle unit and the cleaning blade provided in the head chip can be improved by cleaning only one head chip by one cleaning unit. 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 may 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 plurality of head chips provided in the print head in a length direction of the nozzle part and having a plurality of nozzle rows; And a plurality of cleaning units having a driving shaft rotated in a predetermined direction and a wiping blade which is installed on the driving shaft so as to rotate on the same plane as the head chip surface and contacts the head chip to clean the waste ink. , And the same number of cleaning units as the number of the head chips so that the cleaning unit cleans only one head chip. The method of claim 1, And the driving shaft is installed in a direction orthogonal to the head chip surface. The method of claim 1, And the wiping blade cleans the head chip while reciprocating at a predetermined angle while drawing a fan shape. The method of claim 1, wherein the plurality of cleaning units, And the wiping blades are alternately installed on both sides of the print head such that the wiping blades do not interfere with each other when the head chip is cleaned. The method according to any one of claims 1 to 4, And the plurality of head chips are arranged in a zigzag.

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