JP2020196188A - Ink jet recording device - Google Patents

Abstract

To reduce occurrence of image defects caused by ink transferred from a wiper member and adhering to a contact member by further reducing elastic deformation of a wiper by the contact member to further reduce ink scattering, and reducing an amount of ink which is scraped by the wiper and is transferred and adheres to the contact member.SOLUTION: An ink jet recording device 1 includes a recording head 36, a wiper member 821, a drive part, a control part 100, and a contact member 84. The contact member 84 is arranged in a position in which a contact surface 840 with the wiper member 821 is farther from the wiper member 821 than an ink discharge surface 361. The wiper member 821 has a predetermined overlap amount of a tip end edge part with the contact surface 840.SELECTED DRAWING: Figure 7

Description

The present invention relates to an inkjet recording apparatus, and more particularly to a technique for cleaning an ink ejection surface of a recording head.

There is an inkjet recording device that ejects ink from a nozzle of a recording head onto a recording medium such as paper and records an image on the recording medium. In such an inkjet recording device, in order to prevent the ink ejected from the nozzle of the recording head from adhering to the nozzle surface, for example, as shown in Patent Document 1 below, a plate-shaped wiper is attached to the tip edge thereof. A cleaning operation has been proposed in which the ink ejection surface is wiped by bringing the ink into contact with the ink ejection surface and moving the ink in the wiping direction.

In the cleaning operation described in Patent Document 1, the wiper moves in the wiping direction while contacting the ink ejection surface, and when the ink ejection surface is completely cleaned, the wiper is placed on the side end portion which is the end of the ink ejection surface. To reach. At this side end, the wiper is released from the state of being pressed and in contact with the ink ejection surface, so that the wiper tries to return from the curved state that was bent by the pressing to the state of being straightened without being pressed. .. At this time, the ink that has been scraped off from the ink ejection surface by the wiper and adhered to the wiper is scattered to the surroundings by the force due to the elastic deformation when the wiper returns from the curved state to the straight extended state. When the ink is scattered in this way, the portion of the device to which the scattered ink is attached is contaminated and deteriorated, and further causes a failure.

In order to solve this problem, in Patent Document 2 below, a slope-shaped blade interfering material (hereinafter referred to as a contact member) provided on the side of the recording head is brought into contact with the entire wiper to suppress sudden elastic deformation of the wiper. The technology has been proposed. Further, Patent Document 3 below proposes a technique for effectively recovering ink adhering to a wiper by using a contact member made of a material having excellent liquid absorption.

Japanese Unexamined Patent Publication No. 2001-205816 Japanese Unexamined Patent Publication No. 7-214785 Japanese Unexamined Patent Publication No. 2001-180013

However, in the techniques described in Patent Documents 2 and 3, the contact member can reduce ink scattering due to elastic deformation of the wiper, but the ink scraped by the wiper moves to the contact member and adheres to the contact member. Therefore, as the accumulation of ink adhering to the contact member progresses, the contact member is next to the recording head, and therefore, when the recording paper passes through the arrangement position of the contact member during printing, it adheres to the contact member. Ink adheres to the recording paper. As a result, image defects due to dirt on the recording paper may occur.

The present invention has been made in view of the above circumstances, and the amount of ink scraped by the wiper transferred to the contact member by further reducing the elastic deformation of the wiper by the contact member to further reduce ink scattering. It is an object of the present invention to reduce the occurrence of image defects caused by the ink that has moved from the wiper member and adhered to the contact member.

The inkjet recording apparatus according to one aspect of the present invention has a recording head having an ink ejection surface having a plurality of ink ejection ports from which ink is ejected, and a plate shape, and a tip edge portion presses against the ink ejection surface. The wiper member that performs a cleaning operation that wipes the ink ejection surface, the drive unit that drives the wiper member, and the drive unit are controlled by contacting and moving in a predetermined wiping direction in this state. A control unit for causing the wiper member to perform a cleaning operation and a contact member arranged adjacent to the end portion of the recording head in the wiping direction and in contact with the tip edge portion of the wiper member are provided. The member is disposed at a position where the contact surface with the wiper member is farther from the ink ejection surface than the ink ejection surface, and the wiper member further determines the amount of overlap of the tip edge portion with respect to the contact surface in advance. It has only the specified value.

According to the present invention, the elastic deformation of the wiper is further reduced by the contact member, the ink scattering is further reduced, and the amount of ink scraped off by the wiper is transferred to the contact member and adhered to the contact member, so that the ink is transferred from the wiper member. It is possible to reduce the occurrence of image defects caused by the ink adhering to the contact member as compared with the conventional case.

It is sectional drawing which showed the structure of the inkjet recording apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the state which the transport unit moved to the lower maintenance position, and the cleaning part moved to the position just below a recording part. It is a functional block diagram which roughly showed the main internal structure of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure which showed the recording part and the transport unit. It is a top view of the transport unit and the recording unit. (A) is a partially broken side view showing a state in which the ink tray and the wiper unit of the cleaning unit are arranged below the recording unit. (B) is a view of the ink ejection surface of the recording head viewed from below. (A) and (B) are views showing a state in which the ink ejection surface and the wiper member are visually recognized from below. It is an enlarged view of the end portion of the recording head in the wiping direction and the portion to which the contact member is attached. (A) to (E) are partially broken side views for explaining a cleaning operation. (A) is a perspective view showing an end portion of the recording head and a contact surface portion of the contact member, and (B) is a side view showing an end portion of the recording head and a contact surface portion of the contact member. It is a figure which shows the result of having measured the influence degree of the dirt by the ink adhering to a contact surface by an experiment. It is a figure which shows the result of having measured the influence degree of the dirt by the ink adhering to a contact surface by an experiment. It is a figure which shows the result of having measured the influence degree of the dirt by the ink adhering to a contact surface by an experiment.

Hereinafter, the inkjet recording apparatus according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional front view showing the configuration of an inkjet recording device according to the first embodiment of the present invention. FIG. 2 is a diagram showing a state in which the transport unit has moved to a lower maintenance position and the cleaning unit has moved to a position directly below the recording unit. The inkjet recording device 1 is a multifunction device having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. The device main body 11 includes an operation unit 47, a document feeding unit 6, and a document. It includes a reading unit 5, an image recording unit 12, a paper feeding unit 14, a paper transport unit 19, a transport unit 125, and a cleaning unit 8.

The operation unit 47 receives instructions such as an image recording operation execution instruction from the operator for various operations and processes that can be executed by the inkjet recording device 1. The operation unit 47 includes a display unit 473 that displays operation guidance and the like to the operator.

A case where the document reading operation is performed by the inkjet recording device 1 will be described. The document reading unit 5 optically reads the image of the document fed by the document feeding unit 6 or the document placed on the platen glass 161 and generates image data. The image data generated by the document reading unit 5 is stored in an image memory or the like (not shown).

The document reading unit 5 includes a reading mechanism 163 having a light source emitting unit, a CCD (Charge Coupled Device) sensor, and the like, and the document reading unit 5 irradiates a document using a light irradiation unit having a light source and reflects the document. An image is read from a document by receiving light with a CCD sensor.

A case where the image recording operation is performed by the inkjet recording device 1 will be described. Based on the original image data generated by the original reading operation, the original image data stored in the image memory, the original image data received from the computer connected to the network, and the like, the image recording unit 12 sets the paper feeding unit 14 The image is recorded on the paper P which is fed from the paper and is conveyed by the paper conveying unit 19.

The paper feed unit 14 includes a paper feed cassette 141. A paper feed roller 145 is provided above the paper feed cassette 141, and the paper P housed in the paper feed cassette 141 is fed out toward the transport path 190 by the paper feed roller 145.

Further, the paper feed unit 14 includes a manual feed tray 142 that is openably and closably provided on the wall surface of the apparatus main body 11. The paper P set in the bypass tray 142 is fed out toward the transport path 190 by the paper feed roller 146.

The paper transport unit 19 includes a transport path 190 for transporting the paper P from the paper feed section 14 toward the discharge tray 151, a transport roller pair 191 provided at an appropriate position in the transport path 190, and a discharge roller pair 192.

The paper P fed from the paper feed unit 14 is conveyed in the transfer path 190 by the transfer roller pair 191. Further, the paper P on which the image is recorded by the image recording unit 12 is face-up and is discharged to the discharge tray 151 by the discharge roller pair 192 through the paper discharge transport path 193 (a part of the transport path 190).

Further, the paper transport unit 19 has an offset mechanism (not shown) that moves the discharge roller pair 192 in a direction perpendicular to the paper transport direction and shifts the paper P to be discharged to the discharge tray 151 in the paper width direction.

The image recording unit 12 records an image based on the original image data on the paper P that is fed from the paper feeding unit 14 and conveyed through the conveying path 190, and the conveying unit 125, the suction roller 126, and the recording unit 3 And an ink tank 122.

The transport unit 125 includes a drive roller 125A, a driven roller 125B, a tension roller 127, and a transport belt 128. The transport belt 128 is an endless belt, and is bridged over a drive roller 125A, a driven roller 125B, and a tension roller 127. The drive roller 125A is a roller that is rotationally driven counterclockwise by a motor (not shown). When the drive roller 125A is rotationally driven, the transport belt 128 travels counterclockwise, and the driven roller 125B and tension Roller 127 rotates in a counterclockwise direction.

The tension roller 127 is a roller for keeping the tension state of the transport belt 128 in an appropriate state. The suction roller 126 is arranged to face the driven roller 125B in contact with the transport belt 128, and by charging the transport belt 128, the paper P fed from the paper feed unit 14 is electrostatically charged to the transport belt 128. Adsorb.

The recording unit 3 ejects ink droplets of four different colors (black, cyan, magenta, and yellow) toward the paper P transported by the paper transport unit 19, and sequentially records images. The ink tank 122 is filled with ink corresponding to each color.

Specifically, the recording unit 3 has line heads 31, 32, 33, and 34 corresponding to each color of black, cyan, magenta, and yellow. Therefore, the inkjet recording device 1 is a line head type inkjet recording device. Further, the recording unit 3 has a head frame 35 (see FIGS. 4A and 4B) that supports the line heads 31 to 34. The head frame 35 is supported by the device main body 11.

The elevating mechanism 129 supports the transport unit 125 from below, and raises and lowers the transport unit 125 up and down with respect to the line heads 31 to 34. That is, the elevating mechanism 129 separates and approaches the transport unit 125 and the line heads 31 to 34 by moving the transport unit 125 relative to the line heads 31 to 34. Specifically, the elevating mechanism 129 has a recording position (position shown in FIG. 1) where printing by the recording unit 3 is possible and a maintenance position (position shown in FIG. 2) separated from the recording position by a predetermined distance. ), And the transport unit 125 is moved.

FIG. 3 is a functional block diagram schematically showing the main internal configuration of the inkjet recording device according to the first embodiment. The inkjet recording device 1 includes a control unit 10, a document feeding unit 6, a document reading unit 5, an image recording unit 12, a paper feeding unit 14, a paper transport unit 19, an operation unit 47, a drive mechanism 88, a transport unit 125, and an elevating mechanism. It includes 129, a cleaning liquid pump 130, and a cleaning unit 8. The same components as those of the inkjet recording device 1 shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted here.

The paper feed unit 14 and the paper transport unit 19 include roller drive units 14A and 19A, respectively. The roller drive units 14A and 19A are composed of a motor, a gear, a driver, and the like, and the roller drive unit 14A functions as a drive source for applying a rotational driving force to the paper feed rollers 145 and 146. The roller drive unit 19A functions as a drive source for applying a rotational driving force to the drive rollers of the transport roller pair 191 and the discharge roller pair 192.

The control unit 10 includes a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), an MPU (Micro Processing Unit), or the like. The control unit 10 includes a control unit 100.

The control unit 10 functions as a control unit 100 by operating the processor according to a control program stored in a built-in non-volatile memory or the like. However, the control unit 100 and the like can be configured by hardware circuits, regardless of the operation according to the control program by the control unit 10. Hereinafter, the same applies to each embodiment unless otherwise specified.

The control unit 100 controls the overall operation of the inkjet recording device 1. The control unit 100 includes a document feeding unit 6, a document reading unit 5, an image recording unit 12, a paper feeding unit 14, a paper transport unit 19, a cleaning unit 8, an operation unit 47, a transport unit 125, an elevating mechanism 129, and a drive mechanism 88. And is connected to the cleaning liquid pump 130, and controls the drive of each of these parts.

By driving and controlling the drive mechanism 88, the control unit 100 causes a cleaning operation of wiping the ink ejection surface 361 by the wiper member 821 using the cleaning liquid 831 as described later. The drive mechanism 88 is a drive mechanism of the wiper member 821 including a rack-pinion mechanism and a drive source (drive motor or the like).

Here, the configuration of the recording unit 3 will be described in detail with reference to the drawings. FIG. 4A is a diagram showing a recording unit and a transport unit. FIG. 4B is a plan view of the transport unit and the recording unit as viewed from above.

As shown in FIG. 4A, the transport unit 125 is arranged below the line heads 31 to 34. The transport unit 125 transports the paper P by the transport belt 128 while facing the ink ejection surface 361. The gap between the transport belt 128 and the ink ejection surface 361 is set to a size that allows the paper P to pass through, and the gap between the surface of the paper P and the ink ejection surface 361 during image recording is adjusted to be, for example, 1 mm. To.

As shown in FIG. 4B, the recording unit 3 includes line heads 31 to 34. The line heads 31 to 34 are long in the direction D2 (width direction of the paper P) perpendicular to the transport direction D1 of the paper P. The width of the line heads 31 to 34 has a length corresponding to the width of the maximum width of the paper P to be conveyed. Each of the line heads 31 to 34 is fixed to the head frame 35 at predetermined intervals along the transport direction D1 of the paper P. Each of the line heads 31 to 34 has a plurality of recording heads 36 (in the present embodiment, an example of three is shown). Therefore, the recording unit 3 includes 12 recording heads 36.

The recording head 36 has a plurality of ink nozzles 37 having an ink ejection port 371 from which ink is ejected. Although the plurality of ink nozzles 37 are briefly shown in FIG. 4B in a manner of being arranged in one row, they may be arranged in three rows in a staggered manner as shown in FIG. 5 (B) described later. Good. The lower surface of the recording head 36 (the surface facing the paper P) is the ink ejection surface 361 provided with the ink ejection port 371. In the present embodiment, in the line head 31, three recording heads 36 are arranged in a staggered pattern along the direction D2. Further, in each of the other line heads 32 to 34, similarly to the line head 31, three recording heads 36 are arranged in a staggered manner along the direction D2.

The recording unit 3 records an image on the paper P by ejecting ink from each ink nozzle 37 of each recording head 36 with respect to the paper P conveyed by the transport unit 125. As the ink ejection method of the line heads 31 to 34, for example, a piezo system in which ink is ejected by using a piezo element, a thermal method in which bubbles are generated by heating to eject ink, and the like are adopted.

As shown in FIG. 1, the ink tank 122 includes ink tanks 41, 42, 43, and 44 containing inks corresponding to each of the black, cyan, magenta, and yellow colors. The ink tanks 41 to 44 are connected to the line heads 31 to 34 of the same color by ink tubes (not shown). The line heads 31 to 34 are replenished with ink from each of the ink tanks 41 to 44. Here, as the ink, for example, an ink in which a color material corresponding to each color is contained in a solvent and water is used.

Subsequently, the cleaning unit 8 will be described with reference to FIGS. 5A and 5B. FIG. 5A is a partially broken side view showing a state in which the ink tray and the wiper unit of the cleaning unit are arranged below the recording unit. FIG. 5B is a view of the ink ejection surface of the recording head.

As shown in FIG. 2, the cleaning unit 8 recovers the functions of the recording heads 36 of each of the line heads 31 to 34 by performing a cleaning operation (including a purging operation) when the transport unit 125 is in the maintenance position. It is a device to make it. As shown in FIGS. 1 and 5A, the cleaning unit 8 has an ink tray 81, a wiper unit 82, and a drive mechanism 88.

The ink tray 81 receives the ink discharged from the ink nozzles 37 of the respective recording heads 36. The ink tray 81 is movably supported in the horizontal direction (horizontal direction in FIG. 1) by the first moving mechanism (not shown). The first movement mechanism is a known drive mechanism that moves the ink tray 81 in the horizontal direction by using, for example, a rack-pinion mechanism that converts the rotational movement of a gear connected to the rotation shaft of a motor into a linear movement. is there. In the normal state (during printing), the ink tray 81 is arranged at a retracted position (see the position indicated by the alternate long and short dash line in FIG. 2) retracted to the downstream side of the transport direction D1 from the recording unit 3.

Then, when the user inputs an instruction to perform the cleaning operation by the operation unit 47, the control unit 100 moves the transport unit 125 to the maintenance position by the elevating mechanism 129, and further, the ink tray 81 is moved to the maintenance position. The first moving mechanism is used to move the line heads 31 to 34 into the spaces facing each other (see the positions shown by the solid lines in FIG. 2). Further, the ink tray 81 is supported so as to be able to move up and down in the vertical direction (vertical direction in FIG. 2). When the ink tray 81 moves to the opposite position of the line heads 31 to 34, the transport unit 125 is raised by a predetermined distance from the maintenance position by the elevating mechanism 129, so that the ink tray 81 moves upward.

The wiper unit 82 has a configuration in which a plurality of wiper members 821 for cleaning ink and the like adhering to each ink ejection surface 361 are supported by a pair of side frames 823 via a plurality of stays 822. Further, the wiper unit 82 can move along the direction D2. In particular, the plurality of wiper members 821 come into contact with the ink ejection surface 361 of the recording head 36 and can move from the position of the cleaning liquid supply unit 83 in the wiping direction D21.

The plurality of wiper members 821 move along the wiping direction D21 to clean the ink ejection surface 361 with the cleaning liquid 831 supplied from the cleaning liquid supply unit 83.

As shown in FIG. 5A, the cleaning liquid storage unit 85 stores the cleaning liquid 831. Here, as the cleaning liquid 831, for example, an ink obtained by removing the coloring material can be used. That is, as the cleaning liquid 831, one containing a solvent and water as main components can be used. Further, a surfactant, an antiseptic and an antifungal agent and the like are added to the cleaning liquid 831 as needed.

Here, the plurality of wiper members 821 are formed in a plate shape having a thickness of 1 mm to 2 mm by, for example, an elastomer, and have elasticity. Examples of the elastomer include urethane rubber, ethylene propylene diene rubber (EPDM), nitrile rubber (NBR), styrene rubber (SBR), chloroprene rubber, silicone rubber, and fluorine rubber. The wiper member 821 has a plate-like shape, but is provided in a posture in which a flat surface portion is orthogonal to the ink ejection surface 361. Further, the wiper member 821 is cleaned by wiping the ink ejection surface 361 by contacting the wiper member 821 with the tip edge thereof pressed against the ink ejection surface 361 and moving in the predetermined wiping direction D2. Do the action.

The plurality of stays 822 extend along the transport direction D1. Both ends of each stay 822 are connected to the side frame 823, respectively. That is, a plurality of stays 822 are attached between a pair of side frames 823 provided in parallel in a posture orthogonal to each side frame 823. In the present embodiment, the number of the plurality of stays 822 is three. As shown by the broken line in FIG. 4B, each stay 822 extends in the direction in which a plurality of line heads provided for each color are lined up. Also as shown in FIG. 4B, each line head has three recording heads 36. The three recording heads 36 included in the line head are arranged side by side in the extending direction of the stay 822 at the same positions in the direction D2 as the corresponding recording heads 36 included in the other line heads. The stay 822 is arranged at a position approaching the recording head 36 in each line head arranged at the same position in the direction D2. A wiper member 821 is fixed to each stay 822 at a position facing the four recording heads 36 arranged in this way (a total of four wiper members 821 are provided in one stay 822). The number of the plurality of wiper members 821 is 12 corresponding to the number of the recording heads 36.

The pair of side frames 823 are configured to reciprocate along the direction D2 by the drive mechanism 88 (FIG. 3). The drive mechanism 88 is a drive mechanism including a rack-pinion mechanism and the like as described above. For example, by applying a rotational force supplied from a drive source (drive motor, etc.) of the drive mechanism 88 to the side frame 823 that functions as a rack via a pinion gear (not shown) of the drive mechanism 88, the side frame 823 functions as a rack. The frame 823 is configured to reciprocate along the direction D2. As a result, the entire wiper unit 82 including each stay 822 and the plurality of wiper members 821 reciprocates along the direction D2. As a result, each wiper member 821 wipes the ink ejection surface 361 of the recording head 36 provided at the opposite position. The side frame 823, stay 822, and drive mechanism 88 are examples of "drive units" within the scope of the claims.

Here, the posture of the wiper member 821 will be described with reference to FIG. 6A. When the ink ejection surface 361 and the wiper member 821 are visually recognized from below, the wiper member 821 is provided in a posture in which the tip edge portion thereof extends in a direction orthogonal to the wiping direction. While maintaining the posture, the wiper member 821 is moved in the direction D2 while the tip edge portion is in contact with the ink ejection surface 361 by the side frame 823, the stay 822, and the drive mechanism 88 under the control of the control unit 100. Move to perform cleaning operation.

Further, the height of the tip edge portion of the wiper member 821 is set to overlap the ink ejection surface 361 by a predetermined length (for example, 2 mm). As a result, the wiper member 821 is in a bent state when it is pressed against and in contact with the ink ejection surface 361.

As shown in FIGS. 5A and 5B, the recording head 36 is provided with a cleaning liquid supply unit 83 on the upstream side of the ink ejection surface 361 in the wiping direction D21. The cleaning liquid supply unit 83 includes a cleaning liquid supply surface 865 having a cleaning liquid supply port 834 for supplying the cleaning liquid 831 used for wiping the ink ejection surface by the wiper member 821, and is provided on the upstream side of the ink ejection surface 361 in the wiping direction D21. ing.

The cleaning liquid supply unit 83 includes an inclined surface 866 that is continuously located on the upstream side of the wiping direction D21 and is inclined upward with respect to the cleaning liquid supply surface 865 as it advances to the upstream side of the wiping direction D21. ing.

As shown in FIG. 4B, the recording unit 3 includes twelve recording heads 36, and thus has a plurality (12) cleaning liquid supply units 83. The plurality (12) cleaning liquid supply units 83 supply cleaning liquid 831 for cleaning the ink ejection surface 361. When the ink ejection surface 361 is cleaned by the wiper member 821, the cleaning liquid supply unit 83 supplies the cleaning liquid 831 stored in the storage space 832 via the cleaning liquid nozzle 833 that communicates with the storage space 832.

As shown in FIG. 8A, which will be described later, the cleaning liquid 831 is supplied in a state of hemispherically protruding from the cleaning liquid supply port 834 provided in the cleaning liquid nozzle 833 when cleaning the ink ejection surface 361. On the other hand, the cleaning liquid 831 forms a concave meniscus inside the cleaning liquid nozzle 833 except when cleaning the ink ejection surface 361. Here, the concave meniscus is formed by adjusting the inner diameter of the cleaning liquid nozzle 833, the negative pressure that the accommodating space 832 acts on the inside of the cleaning liquid nozzle 833, and the like.

Further, as shown in FIGS. 5A and 5B, the recording head 36 is provided with a contact member 84 downstream of the ink ejection surface 361 in the wiping direction D21. The contact member 84 is arranged adjacent to the end of the recording head 36 (ink ejection surface 361) in the wiping direction D21, and comes into contact with the tip edge of the wiper member 821.

Then, as shown in FIG. 6A, the contact member 84 has an ink ejection surface in the direction orthogonal to the wiping direction when the ink ejection surface 361 and the wiper member 821 are visually recognized from below. It is the same as the width of 361.

As shown in FIG. 6B, the contact member 84 is orthogonal to the direction in which the tip edge portion of the wiper member 821 extends (orthogonal to the wiping direction) when the ink ejection surface 361 and the wiper member 821 are visually recognized from below. The dimension in the direction) may be a dimension that contacts only a part of the tip edge portion in the direction.

In the present embodiment, the contact member 84 will be described by taking the embodiment shown in FIG. 6A as an example.

Here, the contact member 84 will be described in more detail. FIG. 7 is an enlarged view of an end portion of the recording head 36 in the wiping direction and a portion to which the contact member is attached.

As shown in FIG. 7, in the contact member 84, the contact surface 840 with the wiper member 821 is provided above the ink ejection surface 361. That is, the contact surface 840 is arranged at a position farther from the wiper member 821 than the ink ejection surface 361.

The height difference d between the contact surface 840 and the ink ejection surface 361 is, for example, a value larger than 0 mm and 1.8 mm or less when the overlap amount E1 with respect to the ink ejection surface 361 at the tip edge of the wiper member 821 is 2 mm. Will be done. In this case, the tip edge portion of the wiper member 821 is further provided so as to overlap the contact surface 840, and the overlap amount E2 is, for example, at least 0.2 mm. That is, the distance d between the ink ejection surface 361 and the contact surface 840 of the contact member 84 is larger than 0 mm, and the wiper with respect to the contact surface 840 is determined from the amount of overlap of the tip edge portion of the wiper member 821 with respect to the ink ejection surface 361. It is set to be equal to or less than the value obtained by subtracting the overlap amount of the tip edge portion of the member 821 (0 <d ≦ E1-E2).

Further, the contact member 84 preferably has the following configuration. The contact member 84 has a range R in which the length L in the wiping direction varies in the wiping direction at the stop position of the wiper member 821 at the end of the recording head 36 at the end of the cleaning operation, and the wiper member with respect to the ink ejection surface 361. Deflection amount DF in the wiping direction of 821 (in the wiping direction from the position of the center in the wiping direction of the wiper member 821 that is considered to be upright to the tip edge portion that is bent by pressing the ink ejection surface 361. The length is equal to or greater than the total value of (distance) (L ≧ R + DF). For example, when the variation range R is 1 mm and the deflection amount DF is 1.5 mm, the length of the contact member 48 in the wiping direction is 2.5 mm or more.

The contact member 84 is made of, for example, a polyacetal resin (POM). The ink ejection surface 361 of the recording head 36 is, for example, treated with a fluorine-based water-repellent film. The contact surface 840 of the contact member 84 is formed to have a lower ink repellency than the ink ejection surface 361.

8 (A) to 8 (E) are partially broken side views for explaining a cleaning operation.

As shown in FIG. 8A, the control unit 100 supplies the purge ink 45 to the recording head 36, and discharges the purge ink 45 from the ink ejection port 371 of the ink nozzle 37. As a result, the thickening ink, foreign matter, air bubbles, etc. in the ink nozzle 37 are discharged toward the ink tray 81 together with the purge ink 45 supplied to the ink nozzle 37. By performing such a purging operation, clogging of the ink nozzle 37 is eliminated. The ink discharged to the ink tray 81 is discharged from the discharge port provided at the bottom of the ink tray 81 to a predetermined waste ink storage unit through an ink tube (not shown).

After the purging operation, the cleaning unit 8 performs a cleaning operation. The cleaning operation is an operation for wiping the purge ink 45 adhering to the ink ejection surface 361 with the wiper member 821. In the cleaning operation, the control unit 100 pushes out a predetermined amount (for example, 1.5 mL) of the cleaning liquid 831, and the cleaning liquid 831 is hemispherically projected from the cleaning liquid supply port 834 of the cleaning liquid supply unit 83 and supplied (FIG. FIG. 8 (A)). The predetermined amount (for example, 1.5 mL) is the total extrusion amount of each line head 31 to 34, that is, the extrusion amount for the total of four colors. Further, the cleaning liquid 831 may be supplied at the same time as the purge ink 45 is discharged, or before or after the purge ink 45 is discharged.

After the supply of the cleaning liquid 831 is completed, the control unit 100 drives the drive mechanism 88 to horizontally move the wiper unit 82 along the wiping direction D21 as shown in FIGS. 8 (B) to 8 (D). .. Specifically, the control unit 100 positions the wiper member 821 at the movement start position (see FIG. 8B), and the end position (FIG. 8 (FIG. 8)) at which the wiper member 821 is in contact with the contact member 84 from the movement start position. D) Refer to) to move the wiper member 821. At this time, as shown in FIGS. 8 (B) to 8 (D), the wiper member 821 moves through the inclined surface 866, the cleaning liquid supply port 834, and the ink ejection surface 361, and comes into contact with the contact member 84.

As shown in FIG. 8D, when the plurality of wiper members 821 move in contact with the ink ejection surface 361, after wiping off the purge ink 45 and the like adhering to the ink ejection surface 361, the ink ejection surface 361 It reaches the side end portion which is the end of the ink, and further reaches the position of the contact member 84. The residual ink or the like wiped off by the wiper member 821 moves together with the wiper member 821, or moves downward along the surface of the wiper member 821 together with the cleaning liquid 831 and falls on the ink tray 81. Therefore, since the wiper member 821 is separated from the contact member 84, no liquid residue is generated on the ink ejection surface 361.

When the wiper member 821 moves in the wiping direction while contacting the ink ejection surface 361 and finishes cleaning the ink ejection surface 361, the wiper member 821 reaches the side end portion which is the end of the ink ejection surface 361. At this time, at the side end portion, the wiper member 821 is released from the state of being pressed and in contact with the ink ejection surface 361. Then, the wiper member 821 starts to return from the curved state of being bent and bent by the above pressure to the state of being straightened without being pressed.

Then, the tip edge portion of the wiper member 821 comes into contact with the contact surface 840 of the contact member 84 when it is separated from the ink ejection surface 361. As described above, the contact surface 840 of the contact member 84 has a height difference d and is provided above the ink ejection surface 361, and the tip edge portion of the wiper member 821 is provided with respect to the ink ejection surface 361. It has an overlap amount E1. Therefore, the elastic deformation generated when the wiper member 821 separates from the ink ejection surface 361 is suppressed until the tip edge portion abuts on the contact surface 840. Therefore, the amount of ink scattered around the wiper member 821 due to the elastic deformation at this time is reduced.

After that, the wiper member 821 advances in the wiping direction D21 while contacting the contact surface 840 of the contact member 84, and the tip edge portion thereof separates from the contact surface 840 at the end portion of the contact surface 840 in the wiping direction D21. The tip edge of the wiper member 821 is released from the pressure on the contact surface 840 and tries to return to a straight stretched state without being pressed. However, the elastic deformation at this time causes the wiper member 821 to separate from the ink ejection surface 361. It is less than the case of returning directly to the straight stretched state. Further, when the tip edge portion of the wiper member 821 is separated from the contact surface 840, a part of the ink adhering to the wiper member 821 moves to the contact surface 840 due to the contact with the contact surface 840 and adheres. Therefore, the amount of ink scattered around the wiper member 821 due to the elastic deformation at this time is further reduced as compared with the case where the wiper member 821 is separated from the ink ejection surface 361 and directly returns to a straight stretched state. Become.

Since the contact surface 840 of the contact member 84 is formed to have a lower ink repellency than the ink ejection surface 361, it moves from the wiper member 821 to the contact surface 840 and adheres to the contact surface 840 by moving in the wiping direction D21. The droplet height (droplet thickness) of the ink is lower than the droplet height of the ink when it adheres to the ink ejection surface 361 (the droplet thickness is smaller). Further, since the contact surface 840 has a height difference d with respect to the ink ejection surface 361, when the paper P passes below the contact surface 840 to which the ink adheres in the wiping direction D21, the contact surface 840 is used from the contact surface 840. The risk of ink transferring to and adhering to the paper P can be reduced as compared with the case where the paper P passes below the contact surface 840 which does not have the above-mentioned condition of low ink repellency and does not have a height difference d. In this embodiment, the paper P is conveyed with a gap of 1 mm with respect to the ink ejection surface 361.

Further, as shown in FIGS. 9A and 9B, the contact member 84 may have an inclined surface 841. The inclined surface 841 is located on the downstream side of the wiping direction D21 continuously with the ink ejection surface 361, and is inclined upward with respect to the ink ejection surface 361 as it advances to the downstream side of the wiping direction D21. That is, in the contact member 84, the contact surface of the wiper member 821 with the tip edge portion increases the height difference d as the wiper member 821 separates from the ink ejection surface 361 in the wiping direction. It is said to be an inclined surface 841 away from. The inclined surface 841 also functions as a contact surface 840.

Therefore, as the wiper member 821 advances in the wiping direction D21 while contacting the inclined surface 841 of the contact member 84, the deflection of the wiper member 821 gradually decreases, and finally the tip of the wiper member 821 The edge is gently separated from the inclined surface 841. Therefore, the elastic deformation generated when the tip edge portion of the wiper member 821 is released from the pressure on the inclined surface 841 is reduced, so that the amount of ink scattered around at this time can be further reduced. In addition, when the paper P is sucked by applying a negative pressure to the paper P in a direction away from the ink ejection surface 361 and the contact surface 840 (downward), the suction is performed. Since the height of the ink droplets (droplet thickness) is larger than that without the ink droplets, the contact surface 840 is provided when the paper P passes below the contact surface 840 to which the ink is attached by providing the inclined surface 841. It is possible to further reduce the possibility that the ink is transferred to the paper P and adheres to the paper P.

Subsequently, as shown in FIG. 8E, the control unit 100 drives the elevating mechanism 129 to lower the transport unit 125 by a predetermined distance and return it to the maintenance position.

After that, the control unit 100 drives the elevating mechanism 129 to lower the transport unit 125 to the maintenance position (see FIG. 2), and drives the drive mechanism 88 to return the ink tray 81 of the cleaning unit 8 to the retracted position. (See Fig. 1). Further, the control unit 100 drives the elevating mechanism 129 to return the transport unit 125 to the recording position (position shown in FIG. 1).

In this way, the control unit 100 pushes out the purge ink 45 from the ink ejection port 371 of the recording head and the cleaning liquid 831 from the cleaning liquid supply port 834 to control the cleaning operation, and pushes the wiper member 821 from the movement start position. The wiper member 821 is controlled to be separated from the end position by moving the wiper member 821 in the wiping direction D21 to the end position which is a position where the contact member 84 is contacted through the discharge surface 361.

Further, the present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above embodiment, the ink repellency of the contact surface 840 of the contact member 84 is lower than the ink repellency of the ink ejection surface 361, but (i) the ink repellency of the contact surface 840 is lowered in this way. In this case, when the inclined surface 841 is provided, the angle of the inclined surface 841 with respect to the ink ejection surface 361 is set to less than 45 degrees, and (ii) the ink repellency of the contact surface 840 is defined as the ink repellency of the ink ejection surface 361. If they are equivalent, the angle may be 45 degrees or more. As a result, when the paper P passes below the contact surface 840 to which the ink has adhered, the possibility that the ink will move from the contact surface 840 to the paper P and adhere to the paper P can be more accurately reduced.

Example 1
For each form in which the amount of overlap of the wiper member 821 with respect to the contact surface 840 (no inclination) was changed, the degree of influence of the ink adhering to the contact surface 840 was measured experimentally for each contact member 84 having a different width. It is shown in FIG. The width of the contact member 84 is 2 mm in the direction orthogonal to the wiping direction (dimension in which the contact member 84 contacts only a part of the tip edge portion of the wiper member 821) and 24 mm in the direction. (The width of the contact member 84 is the same as the width of the ink ejection surface 361).

Regarding the degree of influence of the ink adhering to the contact surface 840, a blank sheet (10 cm square) is placed below the position where the wiper member 821 is separated from the contact member 84 in the wiping direction, and the cleaning operation 20 by the wiper member 821. It was observed after the times. If ink adhered to the blank paper, it was marked as x, and if it did not adhere, it was marked as ○.

Example 2
FIG. 11 shows the results of experimentally measuring the influence of ink stains on the contact surface 840 for each form in which the amount of overlap of the wiper member 821 with respect to the inclined surface 841 was changed for each contact member 84 having a different width. .. The width of the contact member 84 is 2 mm in the direction orthogonal to the wiping direction (dimension in which the contact member 84 contacts only a part of the tip edge portion of the wiper member 821) and 24 mm in the direction. (The width of the contact member 84 is the same as the width of the ink ejection surface 361). Other conditions are the same as in Experiment 1.

Example 3
In Examples 1 and 2, the experimental results of each form in which the width of the contact member 84 is different are shown. However, in the case of the suction method in which negative pressure is applied by a fan for paper transport, the ink adhering to the contact surface 840 is shown. The degree of influence of stains due to is different from that of Examples 1 and 2. FIG. 12 shows the experimental results when the paper transport is a suction method in which a negative pressure is applied by a fan. The contact member 84 was tested for each of the contact surface 840 (no inclination) and the inclined surface 841.

The distance between the transport belt surface used for paper transport and the ink ejection surface 361 was 1.0 mm, and the negative pressure suction was a wind speed of 2 m / sec. In the state where the negative pressure suction was performed, 5 minutes after the start of the negative pressure suction, if ink adhered to the transport belt surface, it was evaluated as x, and if it did not adhere, it was evaluated as ○.

Further, in the above-described embodiment, the configuration and processing shown by the above-described embodiment with reference to FIGS. 1 to 9 are merely one embodiment of the present invention, and the present invention is not intended to be limited to the configuration and processing.

1 Inkjet recording device 10 Control unit 100 Control unit 3 Recording unit 31, 32, 33, 34 Line head 36 Recording head 361 Ink ejection surface 8 Cleaning unit 82 Wiper unit 821 Wiper member 84 Contact member 840 Contact surface 841 Inclined surface 88 Drive mechanism

Claims (6)

A recording head having an ink ejection surface having a plurality of ink ejection ports from which ink is ejected,
A wiper member that has a plate shape and has a tip edge that is in contact with the ink ejection surface and moves in a predetermined wiping direction to perform a cleaning operation that wipes the ink ejection surface. ,
A drive unit that drives the wiper member and
A control unit that controls the drive unit to cause the wiper member to perform a cleaning operation.
A contact member arranged adjacent to the end of the recording head in the wiping direction and in contact with the tip edge of the wiper member.
The contact member is arranged at a position where the contact surface with the wiper member is farther from the wiper member than the ink ejection surface.
Further, the wiper member is an inkjet recording device having a predetermined value of the amount of overlap of the tip edge portion with respect to the contact surface. The length of the contact member in the wiping direction varies with the range of variation in the wiping direction of the stop position of the wiper member at the end of the recording head at the end of the cleaning operation, and the wiper member with respect to the ink ejection surface. The inkjet recording apparatus according to claim 1, wherein the length is equal to or greater than the total value of the amount of deflection in the wiping direction. The distance between the ink ejection surface and the contact surface of the contact member is larger than 0 mm, and the tip edge with respect to the contact surface is determined from the amount of overlap of the tip edge portion of the wiper member with respect to the ink ejection surface. The inkjet recording apparatus according to claim 1 or 2, wherein the value is equal to or less than the value obtained by subtracting the overlap amount of the parts. The inkjet recording apparatus according to any one of claims 1 to 3, wherein the contact surface of the contact member is formed to have lower ink repellency than the ink ejection surface. The contact member according to any one of claims 1 to 4, wherein the size of the wiper member in the direction in which the tip edge portion extends is a dimension in which the contact member contacts only a part of the tip edge portion in the direction. The described inkjet recording device. A claim in which the contact surface of the wiper member with the tip edge portion is an inclined surface that separates from the tip edge portion as the wiper member separates from the ink ejection surface in the wiping direction. The inkjet recording apparatus according to any one of items 1 to 5.