JP4775124B2 - Droplet discharge device - Google Patents

Description

  The present invention relates to a droplet discharge device that discharges droplets.

  In an ink jet printer as a droplet discharge device, ink adheres to a conveying member that conveys a recording medium and a rotating member such as an intermediate transfer member on which an image of ink droplets is formed. Therefore, a cleaning member such as a blade is attached to the rotating member. The rotating body is cleaned by bringing them into contact with each other (see, for example, Patent Documents 1 and 2).

By the way, there is a case where ink accumulates at the contact portion between the blade and the rotating body, and cleaning failure occurs due to the accumulated ink slipping through the contact portion. Further, if the ink collected in the contact portion is left as it is, the ink may dry and thicken and adhere to the cleaning member. In this case, the cleaning performance of the cleaning member is deteriorated and cleaning failure is likely to occur. Become.
JP 2001-179953 A Japanese Patent No. 2873879

  The present invention has been made in consideration of the above facts, and an object thereof is to suppress poor cleaning of a rotating body by a cleaning member.

The liquid droplet ejection apparatus according to claim 1, wherein a liquid droplet ejection head that ejects liquid in droplets, a rotating body to which the liquid ejected from the liquid droplet ejection head adheres, and the rotating body are in contact with each other A cleaning member that cleans the rotating body, and the outer peripheral surface of the rotating body has higher affinity with the liquid discharged from the droplet discharge head on the downstream side in the rotating direction of the rotating body than on the upstream side. A direction in which the contact point between the boundary line and the cleaning member intersects with the rotation direction of the rotating body over time during the rotation of the rotating body. To move the liquid that accumulates in the contact portion between the cleaning member and the rotating body and cannot overcome the boundary line toward the end of the rotating body in a direction intersecting the rotating body rotating direction. Features.

  In the droplet discharge device according to the first aspect, the liquid discharged in the form of droplets from the droplet discharge head (hereinafter simply referred to as “liquid”) adheres to the rotating body. Further, the cleaning member contacts the rotating body and cleans the rotating body.

  By the way, the rotating body is formed with a region where the high affinity with the liquid changes at a certain boundary. In this region, the affinity for the liquid is higher on the downstream side of the boundary line in the rotational direction of the rotating body than on the upstream side.

  For this reason, when the boundary line in the region passes through the contact portion between the cleaning member and the rotator due to the rotation of the rotator, the liquid accumulated in the contact portion between the cleaning member and the rotator becomes the rotator of the boundary line. It tries to stay in a range where the affinity with the liquid on the downstream side in the rotation direction is high.

Here, during the rotation of the rotating body, the contact point between the boundary line and the cleaning member moves toward the end of the rotating body in a direction intersecting the rotating body rotating direction with the passage of time. As a result, the liquid that accumulates at the contact portion between the cleaning member and the rotating body and cannot overcome the boundary line moves in a direction that intersects the rotating body rotation direction.

  That is, every time the boundary line passes through the contact portion between the cleaning member and the rotating body due to the rotation of the rotating body, the liquid accumulated in the contact portion between the cleaning member and the rotating body is crossed in the direction intersecting the rotating body rotation direction. It can be removed at the end. Therefore, compared with the past, it can suppress that the said liquid accumulates in the contact part of a cleaning member and a rotary body, Therefore, the cleaning defect of the rotary body by a cleaning member can be suppressed.

The droplet discharge device according to claim 2 is characterized in that a boundary line is inclined with respect to a direction in which a contact portion between the cleaning member and the rotating body extends.

In the droplet discharge device according to the second aspect, the boundary line is inclined with respect to the direction in which the contact portion between the cleaning member and the rotating body extends. For this reason, while the boundary line passes through the contact portion between the cleaning member and the rotator, a range having a high affinity with the liquid on the downstream side of the boundary line in the rotating body rotation direction intersects the rotating body rotation direction. Since it moves to a direction, it is possible to move the said liquid collected in the contact part of a cleaning member and a rotary body to the direction which cross | intersects a rotary body rotation direction.

  That is, every time the boundary line passes through the contact portion between the cleaning member and the rotating body due to the rotation of the rotating body, the liquid accumulated in the contact portion between the cleaning member and the rotating body is crossed in the direction intersecting the rotating body rotation direction. It can be removed at the end. Therefore, compared with the past, it can suppress that a liquid accumulates in the contact part of a cleaning member and a rotary body, Therefore, the cleaning defect of the rotary body by a cleaning member can be suppressed.

According to a third aspect of the present invention, there is provided a droplet discharge device comprising: a droplet discharge head that discharges liquid in droplets; a rotating body to which the liquid discharged from the droplet discharge head adheres; A cleaning member that cleans the rotating body, and the outer peripheral surface of the rotating body has a smaller contact angle of the liquid discharged from the droplet discharge head on the downstream side in the rotational direction of the rotating body than on the upstream side. And a contact point between the boundary line and the cleaning member is in a direction intersecting with the rotation direction of the rotating body with the passage of time during the rotation of the rotating body. By moving, the liquid that cannot get over the boundary line is moved toward the end of the rotating body in a direction intersecting the rotating body rotation direction.

  In the droplet discharge device according to the third aspect, a region where the magnitude of the contact angle of the liquid changes on a boundary line is formed on the rotating body. In this region, the contact angle of the liquid is smaller on the downstream side of the boundary line in the rotating body rotation direction than on the upstream side, and the liquid is less likely to be repelled.

  For this reason, when the boundary line in the region passes through the contact portion between the cleaning member and the rotating body due to the rotation of the rotating body, the liquid accumulated in the contact portion between the cleaning member and the rotating body rotates the boundary line. Try to stay in the range downstream of the body rotation direction.

Here, during the rotation of the rotating body, the contact point between the boundary line and the cleaning member moves toward the end of the rotating body in a direction intersecting the rotating body rotating direction with the passage of time. As a result, the liquid that accumulates at the contact portion between the cleaning member and the rotating body and cannot overcome the boundary line moves in a direction that intersects the rotating body rotation direction.

  That is, every time the boundary line passes through the contact portion between the cleaning member and the rotating body due to the rotation of the rotating body, the liquid accumulated in the contact portion between the cleaning member and the rotating body intersects the rotating body rotation direction. It is possible to remove it at the end portion. Therefore, compared with the past, it can suppress that a liquid accumulates in the contact part of a cleaning member and a rotary body, Therefore, the cleaning defect of the rotary body by a cleaning member can be suppressed.

The apparatus according to claim 4, border boundary lines, characterized in that it is inclined with respect to the direction in which the contact portion extends between the cleaning member and the rotating member.

In the droplet discharge device according to the fourth aspect, the boundary line is inclined with respect to the direction in which the contact portion between the cleaning member and the rotating body extends. For this reason, while the boundary line passes through the contact portion between the cleaning member and the rotator, the range downstream of the boundary line in the rotating body rotation direction moves in a direction intersecting the rotating body rotation direction. The liquid accumulated in the contact portion between the rotating body and the rotating body can be moved in a direction crossing the rotating body rotating direction.

  That is, every time the boundary line passes through the contact portion between the cleaning member and the rotating body due to the rotation of the rotating body, the liquid accumulated in the contact portion between the cleaning member and the rotating body intersects the rotating body rotation direction. It is possible to remove it at the end portion. Therefore, compared with the past, it can suppress that a liquid accumulates in the contact part of a cleaning member and a rotary body, Therefore, the cleaning defect of the rotary body by a cleaning member can be suppressed.

  According to a fifth aspect of the present invention, there is provided a liquid droplet ejection apparatus, comprising: a liquid droplet ejection head that ejects liquid in droplets; a rotating body to which the liquid ejected from the liquid droplet ejection head adheres; A cleaning member that cleans the rotating body, and a liquid moving unit that moves the liquid discharged from the droplet discharge head and accumulated in a contact portion between the cleaning member and the rotating body in a direction intersecting the rotating body rotation direction; It is characterized by having.

The droplet discharge device according to claim 5 is the droplet discharge device according to any one of claims 1 to 4 , wherein an end of the boundary line is the droplet by the droplet discharge head. It is characterized by being arranged outside the discharge area.

In the droplet discharge device according to claim 5 , the end of the boundary line is disposed outside the droplet discharge region by the droplet discharge head, so that the liquid is a droplet by the droplet discharge head. It can suppress that it retains in the discharge area | region compared with the past.

  Since this invention set it as the said structure, it becomes possible to suppress the cleaning defect of the rotary body by a cleaning member.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Note that the direction of rotation of the conveyor belt 28 as a rotating body (hereinafter referred to as the belt rotation direction) is indicated by an arrow A in the figure.

  FIG. 1 shows an ink jet recording apparatus 12 as a droplet discharge apparatus of the present embodiment. A paper feed tray 16 is provided in the lower part of the casing 14 of the ink jet recording apparatus 12, and the sheets P stacked in the paper feed tray 16 can be taken out one by one by a pickup roll 18. The taken paper P is transported by a plurality of transport roller pairs 20 constituting a predetermined transport path 22.

  Above the paper feed tray 16, an endless transport belt 28 as a rotating body is stretched around a drive roll 24 and driven rolls 26, 27, and 29. The driving roll 24 and the driven roll 26 are disposed substantially horizontally, and the driven rolls 27 and 29 are disposed substantially horizontally below the driving roll 24 and the driven roll 26.

  A recording head array 30 is disposed above the conveyor belt 28 and faces a flat portion 28 </ b> F of the conveyor belt 28 between the drive roll 24 and the driven roll 26. This opposed area is an ejection area SE where ink droplets are ejected from the recording head array 30. The sheet P transported along the transport path 22 is held by the transport belt 28 and reaches the discharge area SE, and ink droplets corresponding to image information are attached from the recording head array 30 in a state of facing the recording head array 30. The

  In this embodiment, the recording head array 30 has a long shape in which the effective recording area is equal to or larger than the width of the paper P (the length in the direction orthogonal to the transport direction), and is yellow (Y) and magenta (M). , Cyan (C), and black (K), four ink jet recording heads (hereinafter referred to as recording heads) 32 as liquid droplet ejection heads corresponding to the four colors, respectively, are arranged along the transport direction. Images can be recorded.

  Each recording head 32 is driven by a head drive circuit (not shown). The head drive circuit has a configuration in which, for example, the ejection timing of ink droplets and the ink ejection port (nozzle) to be used are determined according to image information and a drive signal is sent to the recording head 32.

  The recording head array 30 may be stationary in a direction orthogonal to the transport direction. However, if the recording head array 30 is configured to move as necessary, an image with higher resolution can be obtained by multi-pass image recording. Or the failure of the recording head 32 is not reflected in the recording result.

  Four maintenance units 34 corresponding to the respective recording heads 32 are arranged on both sides of the recording head array 30. As shown in FIG. 2, when performing maintenance on the recording head 32, the recording head array 30 is moved upward, and the maintenance unit 34 moves into the gap formed between the conveyance belt 28 and enters. . Then, a predetermined maintenance operation (suction, wiping, capping, etc.) is performed while facing the nozzle surface.

  Further, an ink tank 35 for storing ink of each color is disposed above the recording head array 30. Each recording head 32 is connected to each ink tank 35.

  As shown in FIG. 3, a charging roll 36 to which a power source 38 is connected is disposed upstream of the recording head array 30 in the belt rotation direction. The charging roll 36 is driven while sandwiching the conveyance belt 28 and the paper P with the driven roll 26, and presses the paper P against the conveyance belt 28. At this time, since a predetermined potential difference is generated between the grounded follower roll 26, the sheet P can be electrostatically adsorbed to the transport belt 28 by applying an electric charge to the sheet P.

  A separation claw 40 is disposed on the downstream side of the recording head array 30 and separates the paper P from the conveyance belt 28. The peeled paper P is conveyed by a plurality of discharge roller pairs 42 that constitute a discharge path 44 on the downstream side of the peeling claw 40 and discharged to a paper discharge tray 46 provided at the upper part of the housing 14.

  A belt cleaning unit 48 is disposed below the peeling claw 40. The belt cleaning unit 48 is in contact with a portion of the transport belt 28 that is wound around the drive roll 24 and scrapes off ink adhering to the transport belt 28. And a recovery box 51 for recovering the ink and the like scraped off. Note that an absorber 53 is spread on the bottom of the collection box 51, and the liquid dropped from the blade 49 is absorbed by the absorber 53.

  Further, a grounded static eliminating roll 62 is disposed on the downstream side of the belt cleaning unit 48 in the belt rotation direction. The neutralizing roll 62 is driven while sandwiching the conveyance belt 28 between the grounded driven roll 27 and removes the electric charge on the conveyance belt 28.

  By the way, as shown in FIG. 4, the outer circumferential surface of the conveyor belt 28 is linear and has hydrophilicity extending along a direction perpendicular to the belt rotation direction (hereinafter referred to as a belt width direction) and a direction inclined. A portion 28A is formed, and a portion other than the hydrophilic portion 28A on the outer peripheral surface of the conveyor belt 28 is a hydrophobic portion 28B having hydrophobicity. The ink ejected from the recording head 32 is water-based ink.

  That is, an area having higher affinity with the water-based ink that is the liquid ejected from the recording head 32 is formed on the outer peripheral surface of the transport belt 28 on the downstream side in the belt rotation direction than on the upstream side. The boundary line 1 in which the affinity for the belt changes varies along the belt width direction and the inclined direction.

  The hydrophilic portion 28A can be formed of polyvinylidene fluoride (PVDF), polyamide (PI), or the like. PVDF has a water contact angle of 86 °, and PI has a water contact angle of 80 °.

  The hydrophobic portion 28B can be formed of polyfluorotetraethylene (PTFE) or the like, or can be formed by post-treatment such as fluorine coating. Here, since the contact angle of water of PTFE is 108 °, the hydrophilic portion 28A is formed of PVDF and PI, and the hydrophobic portion 28B is formed of PTFE, so that the contact angle of the hydrophilic portion 28A with the water-based ink is increased. It can be made smaller than the hydrophobic portion 28.

  The hydrophobic portion 28B can also be formed by roughening the outer peripheral surface of the conveyor belt 28. In this case, if a material having a rough surface is selected as the base material of the conveyor belt 28, post-processing or the like is not necessary. If the surface of the conveyor belt 28 is excessively rough, the cleaning performance is adversely affected. Therefore, it is desirable that the surface roughness of the conveyor belt 28 is set to an appropriate size.

  On the other hand, the blade 49 is in contact with the transport belt 28 along the belt width direction to clean the transport belt 28. For this reason, the hydrophilic portion 28A is inclined with respect to the direction in which the contact portion 2 between the blade 49 and the transport belt 28 extends, and the rotation of the transport belt 28 is performed as shown in FIGS. When the hydrophilic portion 28A passes between the blade 49 and the driving roll 24, the contact point between the hydrophilic portion 28A and the blade 49 moves from one end portion in the belt width direction to the other end portion as time passes. .

  Here, as shown in FIG. 5A, the ink I adhering to the conveyance belt 28 may be collected in the contact portion 2 without being scraped off from the conveyance belt 28 by the blade 49. In this case, when one end of the hydrophilic portion 28A in the belt width direction (end on the downstream side in the belt rotation direction) moves to the contact portion 2 due to the rotation of the transport belt 28, the ink I collected at one end of the contact portion 49 in the belt width direction. Is sucked from the hydrophobic portion 28B to one end of the hydrophilic portion 28A in the belt width direction.

  Then, as shown in FIG. 5B, the belt width direction one end of the boundary line 1 moves to the downstream side in the belt rotation direction from the contact portion 2 by the rotation of the conveying belt 28, and the hydrophilic portion 28 A and the blade 49 The contact point moves to the other end side in the belt width direction. At this time, the ink I sucked to one end portion in the belt width direction of the hydrophilic portion 28A tries to move to the upstream side in the belt rotation direction beyond the one end portion in the belt width direction of the boundary line 1. Since it is repelled by the hydrophobic portion 28B on the upstream side in the rotation direction and attracted to the contact point of the hydrophilic portion 28A with the blade 49, it moves to the other end side in the belt width direction without overcoming the boundary line 1.

  As shown in FIG. 5C, when the contact point between the hydrophilic portion 28A and the blade 49 is moved to the center in the belt width direction by the rotation of the conveying belt 28, the ink I collected in the contact portion 2 is removed from the belt width. As shown in FIG. 5D, when the contact point between the hydrophilic portion 28A and the blade 49 is moved to the other end in the belt width direction due to the rotation of the conveyor belt 28, the contact portion 2 accumulates. Ink I is brought to the other end in the belt width direction.

  Here, the other end in the belt width direction of the conveyance belt 28 is a non-image forming area and a non-paper conveyance area. For this reason, each time the boundary line 1 passes through the contact portion 2, the ink I collected in the contact portion 2 is removed to the non-image forming region and the non-paper transport region, and the blade 49 and the image forming region of the transport belt 28 and the paper Ink I is not collected in the contact portion with the transport area. As a result, ink sticking and ink slippage can be suppressed at the contact portion between the blade 49 and the image forming area of the conveying belt 28 and the sheet conveying area. Accordingly, it is possible to prevent the conveyance failure of the paper P due to the decrease in the electrostatic adsorption force of the paper P to the conveyance belt 28, the contamination of the paper P, and the like.

  Further, since the ink I scraped off from the transport belt 28 by the blade 49 is collected at one place, the collection box 51 is a place where the ink I is collected depending on various conditions such as the amount of the ink I adhering to the transport belt 28. It is sufficient to arrange it on the lower side. Therefore, the collection box 51 can be reduced in size.

  The difference in water contact angle between the hydrophilic portion 28A and the hydrophobic portion 28B is desirably 10 ° or more. Further, the ink I can be moved to the other side in the belt width direction by setting the width of the hydrophilic portion 28A to about several mm to several tens mm and the inclination angle with respect to the rotation axis direction to about 1 to 45 °. When the paper conveyance speed (the rotation speed of the conveyance belt 28) is high, the movement of the ink I is stabilized by widening the width and increasing the inclination angle.

  By the way, the recording head 32 ejects ink regardless of image formation every few seconds to several tens of seconds (so-called dummy jet is performed) in order to prevent clogging of unused nozzles. Is discharged onto the conveyor belt 28.

  At this time, each recording head 32 performs a dummy jet immediately before the hydrophilic portion 28A reaches the ejection area. As a result, as shown in FIG. 6A, since the distance in the belt rotation direction between the hydrophilic portion 28A and the ink I is shortened on the transport belt 28, scraping of the ink I by the blade 49 is started. Immediately thereafter, the movement of the ink I toward the other end in the belt width direction is started, and the ink I is collected. Therefore, since the time for collecting the ink I in the contact portion 2 can be shortened, the cleaning failure of the ink I by the blade 49 can be suppressed.

  Here, the ink is simultaneously ejected from all the nozzles of the recording head 32. However, as shown in FIG. 6B, the hydrophilic portion 28A and the ink I are separated from the belt width direction on the transport belt 28. The timing at which ink is ejected from the nozzles may be shifted so as to incline toward the same side. In this case, when the movement of the ink I toward the other end in the belt width direction at the one end in the belt width direction of the contact portion 2 is started, the ink I still does not collect on the other end in the belt width direction of the contact portion 2. Without the ink I moving to the other end side in the belt width direction, the ink I accumulates on the other end side of the contact portion 2 in the belt width direction. As a result, it is possible to reduce the time for the ink I to accumulate in the entire area of the contact portion 2.

  Further, as shown in FIG. 6C, by controlling the ejection timing of the recording head 32 so that the ink I and the hydrophilic portion 28A overlap, the time for the ink I to accumulate in the contact portion 2 can be further shortened. .

  Further, in the present embodiment, the hydrophilic portion 28A has a shape extending in a straight line while being inclined from the belt width direction one end portion to the other end portion of the transport belt 28 toward the upstream side in the belt rotation direction, as shown in FIG. The conveyor belt 28 extends from one end of the belt width direction to the center in the belt width direction while inclining toward the downstream side in the belt rotation direction, bends at the center portion in the belt width direction, and tilts toward the other end in the belt width direction toward the upstream side in the belt rotation direction. It is good also as a shape extended while doing.

  In this case, since the ink I collected in the contact portion 49 moves to one end and the other end in the belt width direction, it is necessary to provide the collection boxes 51 at both ends in the belt width direction. Therefore, the time for the ink I to accumulate in the contact portion 49 is shortened.

  Next, a modified example of the belt cleaning unit 48 will be described. In addition, the same code | symbol is attached | subjected to the structure similar to the belt cleaning unit 48, and description is abbreviate | omitted.

  As shown in FIG. 8, in the cleaning unit 50, a blade 52 is provided in place of the blade 49 of the first embodiment. The blade 52 is in contact with the transport belt 28 along the belt width direction. Further, a groove 52A extending from the contact portion 2 to the non-contact portion 2 side is formed at the other end portion in the belt width direction on the upstream surface of the blade 52 in the belt rotation direction.

  For this reason, since the ink I collected at the other end in the belt width direction of the contact portion 2 is guided to the collection box 51 side, the amount of ink I collected at the other end in the belt width direction of the contact portion 2 is reduced. . As a result, the scraping performance of the ink I by the other end of the blade 49 in the belt width direction is improved.

  Further, a groove 52B is formed on the upstream surface of the blade 52 in the belt rotation direction so as to extend while inclining from the one end portion in the belt width direction to the other end portion in the direction opposite to the contact portion 2. For this reason, the ink I that has flowed from the contact portion 2 to the non-contact portion 2 side is guided to the groove 52A by the groove 52B. As a result, the ink I scraped off by the blade 52 can be reliably recovered in the recovery box 51 disposed below the other end of the blade 52 in the belt width direction.

  Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment, and description is abbreviate | omitted. In addition, the direction of rotation of the conveyor belt 28 as a rotating body (hereinafter referred to as the belt rotation direction) is indicated by an arrow A in the figure.

  As shown in FIG. 9, in the inkjet recording apparatus 100, the blade 49 comes into contact with the belt in the belt width direction (direction of arrow B in the drawing) and the direction of inclination (direction of arrow C in the drawing) of the conveyance belt 28. 28 is being cleaned. On the other hand, the hydrophilic portion 28 </ b> A extends along the belt width direction of the outer peripheral surface of the conveyance belt 28. Therefore, the boundary line 1 that separates the hydrophilic portion 28A on the downstream side in the belt rotation direction and the hydrophobic portion 28B on the upstream side is inclined with respect to the direction in which the contact portion 2 between the blade 49 and the conveyor belt 28 extends. As shown in FIGS. 10A to 10D, when the hydrophilic portion 28A passes through the contact portion 2 due to the rotation of the conveying belt 28, the contact point between the hydrophilic portion 28A and the blade 49 changes over time. At the same time, the belt moves from one end to the other end in the belt width direction.

  For this reason, as shown in FIG. 10 (A), after the hydrophilic portion 28A moves to the contact portion 2 by the rotation of the conveying belt 28, the end portion in the belt width direction of the contact portion 2 (the lower end portion in the figure). The accumulated ink I is sucked to one end of the hydrophilic portion 28A in the belt width direction.

  Then, as shown in FIG. 10B, the belt width direction one end of the boundary line 1 is moved to the downstream side in the belt rotation direction from the contact portion 2 by the rotation of the conveying belt 28, and the hydrophilic portion 28 A and the blade 49 are moved. The contact point moves to the other end side in the belt width direction. At this time, the ink I sucked to one end portion in the belt width direction of the hydrophilic portion 28A tries to move to the upstream side in the belt rotation direction beyond the one end portion in the belt width direction of the boundary line 1. Since it is repelled by the hydrophobic portion 28B on the upstream side in the rotation direction and attracted to the contact point of the hydrophilic portion 28A with the blade 49, it moves to the other end side in the belt width direction without overcoming the boundary line 1.

  As shown in FIG. 10C, when the contact point between the hydrophilic portion 28A and the blade 49 is moved to the central portion in the belt width direction by the rotation of the conveying belt 28, the ink I accumulated in the contact portion 2 is removed from the belt width. 10D, when the contact point between the hydrophilic portion 28A and the blade 49 is moved to the other end in the belt width direction due to the rotation of the conveyor belt 28, the contact portion 2 accumulates. Ink I is brought to the other end in the belt width direction.

  As a result, as in the first embodiment, the ink I collected in the contact portion 2 can be collected in one place. Therefore, almost all the range of the contact portion 2 is obtained every time the hydrophilic portion 28A passes through the contact portion 2. Ink I is not accumulated.

  In this embodiment, the hydrophilic portion 28A extends along the belt width direction. However, the hydrophilic portion 28A and the contact portion 2 need not be parallel, and as shown in FIG. 28A may be inclined with respect to the belt width direction.

  Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st, 2nd embodiment, and description is abbreviate | omitted. Further, the rotation direction of the intermediate transfer drum 104 as a rotating body (hereinafter referred to as the drum rotation direction) is indicated by an arrow A in the figure.

  As shown in FIGS. 12 and 13, the ink jet recording apparatus 200 as a droplet discharge apparatus according to the present embodiment has four color inks of yellow (Y), magenta (M), black (K), and cyan (C). Thus, the full-color printer forms a full-color image on the paper P. The ink jet recording apparatus 200 is a printer using a so-called offset printing method, and the recording head array 30 ejects ink toward the intermediate transfer drum 104 to temporarily form an ink image on the intermediate transfer drum 104. An ink image is transferred from the intermediate transfer drum 104 to the paper P.

  A paper feed tray 16 is provided at the bottom of the ink jet recording apparatus 200 so that it can be inserted and removed. Sheets P are stacked on the sheet feeding tray 16, and a pickup roll 18 is in contact with the uppermost sheet P. The paper P is fed one by one from the paper feed tray 16 to the downstream side in the transport direction by the pick-up roll 18, and the printing unit 122 is transported by the transport rolls 109, 120, 121, 123, 125 arranged in order along the transport path. Paper is fed to The transport rolls 123 and 125 are star wheels that are in contact with the surface on which the ink image of the paper P is transferred.

  In the printing unit 122, the intermediate transfer drum 104 is disposed facing the conveyance path, the recording head array 30 is disposed above the intermediate transfer drum 104, and the maintenance unit 34 is disposed close to the recording head array 30. Yes.

  As shown in FIG. 12, the recording head array 30 approaches the intermediate transfer drum 14 when ink droplets are ejected. As shown in FIG. 13, the recording head array 30 secures a space for the maintenance unit 24 to enter the intermediate transfer drum 14 away from the intermediate transfer drum 14 during maintenance.

  As shown in FIG. 12, the maintenance unit 34 retreats to the outside of the ejection area SE where ink droplets are ejected from the recording head array 30 during image formation. As shown in FIG. 13, the maintenance unit 34 enters the ejection area SE during non-image formation.

  As shown in FIGS. 12 and 13, the charging roll 128, the charge eliminating roll 130, and the peeling claw 132 are in contact with the intermediate transfer drum 104 in order from the upstream side in the conveyance direction. The charging roll 128 conveys the paper P while pressing it against the intermediate transfer drum 104 and applies a charge to the paper P, thereby electrostatically attracting the paper P to the intermediate transfer drum 104 and transferring the ink image onto the paper P. Further, the static elimination roll 130 removes the charge of the paper P while transporting the paper P, thereby releasing the electrostatic adsorption between the paper P and the intermediate transfer drum 104. The peeling claw 132 peels the paper P from the intermediate transfer drum 104.

  And conveyance roll 127,129,131,133,135,137,139 is arrange | positioned in the conveyance direction downstream of the peeling nail | claw 132 from the conveyance direction upstream. The transport rolls 127, 133, 135, 137, and 139 have a star wheel that is in contact with the surface on which the ink image of the paper P is transferred, and contact between the surface of the paper P on which the ink image is transferred and the roll. Is decreasing.

  A paper discharge tray 46 is disposed above the ink tank 35, and a transport roll 139 is disposed on the side of the paper discharge tray 46. That is, the paper P is discharged onto the paper discharge tray 46 by the transport roll 139.

  As shown in FIG. 14, a drum cleaning unit 148 is disposed on the downstream side of the peeling claw 132 in the drum rotation direction and on the upstream side of the recording head array 30 in the drum rotation direction. The drum cleaning unit 148 abuts on the peripheral surface of the intermediate transfer drum 104, scrapes ink remaining on the intermediate transfer drum 104 without being transferred onto the paper P, and scrapes the intermediate transfer drum 104 with the blade 49. And a collection box 51 for collecting the taken ink and the like. Note that an absorber 53 is spread on the bottom of the collection box 51 and absorbs the liquid dropped from the blade 49.

  Here, as shown in FIG. 15, as in the first embodiment, the blade 49 is in contact with the intermediate transfer drum 104 along a direction orthogonal to the drum rotation direction (hereinafter referred to as the drum width direction). The peripheral surface of the intermediate transfer drum 104 is formed with a hydrophilic portion 104A extending along the direction inclined with respect to the drum width direction. Further, in the range other than the hydrophilic portion 104A on the peripheral surface of the intermediate transfer drum 104, a hydrophobic portion is formed. A sex portion 104B is formed.

  That is, on the outer peripheral surface of the intermediate transfer drum 104, the boundary line 1 that separates the hydrophilic portion 28A on the downstream side in the drum rotation direction and the hydrophobic portion 28B on the upstream side in the drum rotation direction is inclined in the direction in which the contact portion 2 extends. Extending along.

  As a result, the ink I collected in the contact portion 2 can be collected in one place, so that the ink I is not collected every time the hydrophilic portion 28A passes through the contact portion 2 in most areas of the contact portion 2. become.

  In the first to third embodiments, the present invention has been described by taking the ink jet recording apparatus as an example. However, the present invention is not limited to the ink jet recording apparatus, and the display is performed by discharging colored ink onto a polymer film. The present invention can be applied to a general liquid droplet ejection apparatus for various industrial uses such as production of a color filter for liquid crystal and formation of an EL display panel by discharging an organic EL solution onto a substrate.

  The “droplet ejection head” in the droplet ejection apparatus of the present invention includes a wide range of means for ejecting droplets toward a recording medium or a carrier. For example, an ink jet recording head that ejects ink droplets while moving in the width direction of the paper P and shorter than the width of the paper P is included.

  In addition, the “rotor” in the droplet discharge device of the present invention includes a wide range of members as long as the droplet discharged from the droplet discharge head adheres thereto. For example, a drum that holds a recording medium on its peripheral surface and rotates, an intermediate transfer belt, and the like are included.

  Further, the “cleaning member” in the droplet discharge device of the present invention includes a wide range of means for cleaning droplets attached to the carrier. For example, a cleaning roll that rotates in contact with the carrier and absorbs droplets is included.

1 is a side view illustrating an outline of an ink jet recording apparatus according to a first embodiment of the present invention. 1 is a side view illustrating an outline of an ink jet recording apparatus according to a first embodiment of the present invention. It is a side view which shows the outline of the printing part of the inkjet recording device of 1st Embodiment of this invention. FIG. 2 is a perspective view showing a blade and a conveyor belt provided in the ink jet recording apparatus according to the first embodiment of the present invention. (A)-(D) are top views which show the braid | blade and conveyance belt with which the inkjet recording device of 1st Embodiment of this invention was equipped. (A)-(D) are top views which show the braid | blade and conveyance belt with which the inkjet recording device of 1st Embodiment of this invention was equipped. (A), (B) is a top view which shows the modification of the blade with which the inkjet recording device of 1st Embodiment of this invention was equipped. FIG. 2 is a plan view schematically showing ink droplets flowing in a V groove formed on a blade provided in the ink jet recording apparatus according to the first embodiment of the present invention. It is a perspective view which shows the braid | blade and conveyance belt with which the inkjet recording device of 2nd Embodiment of this invention was equipped. (A)-(D) are top views which show the braid | blade and conveyance belt with which the inkjet recording device of 2nd Embodiment of this invention was equipped. It is a top view which shows the modification of the conveyance belt with which the inkjet recording device of 2nd Embodiment of this invention was equipped. It is a side view which shows the outline of the inkjet recording device of 3rd Embodiment of this invention. It is a side view which shows the outline of the inkjet recording device of 3rd Embodiment of this invention. It is a side view which shows the outline of the printing part of the inkjet recording device of 3rd Embodiment of this invention. It is a perspective view which shows the braid | blade and conveyance belt with which the inkjet recording device of 3rd Embodiment of this invention was equipped.

Explanation of symbols

1 Boundary Line 12 Inkjet Recording Device (Droplet Discharge Device)
28 Conveyor belt (rotating body)
32 Inkjet recording head (droplet ejection head)
49 Blade (cleaning member)
100 Inkjet recording device (droplet ejection device)
104 Intermediate transfer drum (rotating body)
200 Inkjet recording device (droplet ejection device)

Claims (5)

A droplet discharge head for discharging liquid in droplets;
A rotating body to which the liquid discharged from the droplet discharge head adheres;
A cleaning member that contacts the rotating body and cleans the rotating body,
The outer peripheral surface of the rotating body has a boundary line with a high affinity so that the downstream side in the rotating body rotation direction has a higher affinity with the liquid discharged from the droplet discharge head than the upstream side. And
When the contact point between the boundary line and the cleaning member moves in a direction intersecting the rotating body rotation direction with the passage of time during the rotation of the rotating body, a contact portion between the cleaning member and the rotating body is formed. A liquid droplet ejecting apparatus, wherein a liquid that accumulates and cannot get over the boundary line is moved toward an end of the rotating body in a direction crossing a rotating body rotating direction.   The droplet discharge device according to claim 1, wherein the boundary line is inclined with respect to a direction in which a contact portion between the cleaning member and the rotating body extends. A droplet discharge head for discharging liquid in droplets;
A rotating body to which the liquid discharged from the droplet discharge head adheres;
A cleaning member that contacts the rotating body and cleans the rotating body,
The outer peripheral surface of the rotating body has a boundary line whose contact angle changes such that the contact angle of the liquid discharged from the droplet discharge head is smaller on the downstream side in the rotating direction of the rotating body than on the upstream side. ,
The contact point between the boundary line and the cleaning member moves in a direction intersecting the rotation direction of the rotating body with the passage of time during the rotation of the rotating body, whereby liquid that cannot get over the boundary line is transferred to the rotating body. A droplet discharge device, wherein the droplet discharge device is moved in a direction crossing a rotating body rotation direction toward an end portion of the rotating body.   The droplet discharge device according to claim 3, wherein the boundary line is inclined with respect to a direction in which a contact portion between the cleaning member and the rotating body extends.   5. The droplet discharge device according to claim 1, wherein an end of the boundary line is disposed outside a droplet discharge region of the droplet discharge head.

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