JP2008018565A - Liquid droplet delivering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress inferior cleaning of a rotating body by a cleaning member. <P>SOLUTION: When a preliminary delivering is performed, a recording head 32 forms a preliminary delivering pattern P on a conveying belt 28. On this preliminary delivering pattern P, straight lines L constituted of several dots of ink drops I stood in the belt width direction are stood in the belt width direction, and a pair of straight lines L adjoining in the belt width direction are offset in the belt rotating direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  In an inkjet printer as a droplet discharge device, it is intended to prevent clogging of nozzles toward 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. Ink droplets that are not related to image formation are ejected (so-called preliminary ejection), and the ink adhering to the rotating body is cleaned by a blade as a cleaning member (see, for example, Patent Document 1).

By the way, when the ink droplets adhering to the rotating body are scraped off by the blade, the ink droplets of a plurality of dots are collected. It has been confirmed that it is easy to collect. In particular, in an ink jet printer using a processing liquid containing a flocculant or the like, the ink and the processing liquid are mixed and thickened on the rotating body, so that the ink tends to accumulate at the contact portion between the blade and the rotating body. It has been confirmed that if the cleaning of the rotating body is continued in a state where the ink is accumulated in the contact portion between the blade and the rotating body, a cleaning failure occurs in which the ink slips between the blade and the rotating body.
JP 2001-179953 A

  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 droplet discharge device according to claim 1, a droplet discharge head that discharges droplets, a rotating body that faces the droplet discharging head, and a cleaning member that contacts the rotating body and cleans the rotating body. In the preliminary discharge, the droplet discharge head has a plurality of lines extending along a direction orthogonal to the rotation direction of the rotating body, and substantially orthogonal to the rotation direction of the rotating body. A pair of the lines arranged in the direction and adjacent to each other in a direction orthogonal to the rotation direction of the rotating body forms a preliminary discharge pattern offset in the rotating direction of the rotating body on the rotating body. .

  The liquid droplet ejection apparatus according to claim 1, wherein the liquid droplet ejection heads perform preliminary ejection (liquid ejection unrelated to image formation for the purpose of preventing clogging of the nozzles) on the rotating members facing each other. )I do. And the droplet adhering on a rotary body is cleaned by the cleaning member which contacted the rotary body.

  Here, the droplet discharge head forms a preliminary discharge pattern, which is a pattern of droplets, on the rotating body during preliminary discharge. In this preliminary discharge pattern, a plurality of lines extending along a direction orthogonal to the rotation direction of the rotating body are arranged in a direction substantially orthogonal to the rotation direction of the rotating body, and in a direction orthogonal to the rotation direction of the rotating body. A pair of adjacent lines is offset in the rotation direction of the rotating body.

  For this reason, when the cleaning member cleans the rotating body, the plurality of droplets constituting one line are integrated, but are separated from the plurality of droplets constituting the adjacent line, and the adjacent line is Since the plurality of constituent droplets are not integrated, the droplets do not exceed a certain size at the contact portion between the cleaning member and the rotating body.

  Therefore, since it can control so that a droplet may not expand excessively in the contact part of a cleaning member and a rotary body, compared with the past, it can control that a liquid accumulates in a contact part of a cleaning member and a rotary body, and cleaning. The cleaning failure of the rotating body by the member can be suppressed.

  The droplet discharge device according to claim 2, wherein a droplet discharge head that discharges droplets, a rotating body that faces the droplet discharging head, and a cleaning member that contacts the rotating body and cleans the rotating body. In the preliminary discharge, the droplet discharge head has a plurality of lines inclined with respect to the rotation direction of the rotating body arranged in a direction substantially orthogonal to the rotation direction of the rotating body. A preliminary discharge pattern is formed on the rotating body.

  In the droplet discharge device according to the second aspect, the droplet discharge head performs preliminary discharge on the rotating bodies facing each other. And the droplet adhering on a rotary body is cleaned by the cleaning member which contacted the rotary body.

  Here, the droplet discharge head forms a preliminary discharge pattern, which is a pattern of droplets, on the rotating body during preliminary discharge. In this preliminary discharge pattern, a plurality of lines inclined with respect to the rotating direction of the rotating body are arranged in a direction substantially orthogonal to the rotating direction of the rotating body.

  For this reason, when the cleaning member cleans the rotating body, a plurality of droplets constituting one line are integrated, but are separated from a plurality of droplets constituting the adjacent line and constitute the adjacent line. Since the plurality of droplets to be integrated are not integrated, the droplet does not exceed a certain size at the contact portion between the cleaning member and the rotating body.

  Thereby, since it can control so that a droplet does not expand excessively in a contact part of a cleaning member and a rotator, compared with the past, it can control that a liquid accumulates in a contact part of a cleaning member and a rotator, The cleaning defect of the rotating body by the cleaning member can be suppressed.

  The droplet discharge device according to claim 3 is the droplet discharge device according to claim 2, wherein the preliminary discharge pattern has a plurality of rows in the rotation direction of the rotating body and is orthogonal to the rotation direction of the rotating body. It is characterized by being arranged by shifting the phase in the direction to be.

  In the droplet discharge device according to claim 3, the preliminary discharge pattern formed in the droplet discharge device according to claim 2 is arranged in a plurality of rows in the rotation direction of the rotating body and in a direction orthogonal to the rotation direction of the rotating body. They are arranged out of phase.

  For this reason, when the cleaning member cleans the rotating body, a plurality of droplets constituting a position where a plurality of droplets constituting one line gather and a line adjacent to the line and the rotation direction of the rotating body gather. Since the position is shifted in a direction perpendicular to the rotation direction of the rotating body, a plurality of droplets constituting a pair of lines adjacent to each other in the rotating direction of the rotating body are separated.

  5. The liquid droplet ejection apparatus according to claim 4, wherein a liquid droplet ejection head that ejects liquid droplets, a rotating body that faces the liquid droplet ejection head, and a cleaning member that contacts the rotating body and cleans the rotating body. The droplet discharge head forms a preliminary discharge pattern on the rotator that extends in a zigzag manner in a direction substantially orthogonal to the rotation direction of the rotator during preliminary discharge. And

  In the droplet discharge device according to the fourth aspect, the droplet discharge head performs preliminary discharge on the rotating bodies facing each other. And the droplet adhering on a rotary body is cleaned by the cleaning member which contacted the rotary body.

  Here, the droplet discharge head forms a preliminary discharge pattern, which is a pattern of droplets, on the rotating body during preliminary discharge. This preliminary discharge pattern extends in a zigzag shape in a direction substantially perpendicular to the rotation direction of the rotating body.

  For this reason, when the cleaning member cleans the rotating body, the plurality of droplets constituting the pair of lines that merge on the upstream side in the rotation direction of the rotating body are integrated, but the plurality of droplets constituting the other lines Since they are not integrated, the droplets do not exceed a certain size at the contact portion between the cleaning member and the rotating body.

  Thereby, since it can control so that a droplet does not expand excessively in a contact part of a cleaning member and a rotator, compared with the past, it can control that a liquid accumulates in a contact part of a cleaning member and a rotator, The cleaning defect of the rotating body by the cleaning member can be suppressed.

  6. The droplet discharge apparatus according to claim 5, wherein a droplet discharge head that discharges droplets, a rotating body that faces the droplet discharging head, and a cleaning member that contacts the rotating body and cleans the rotating body. In the preliminary discharge, the droplet discharge head has a plurality of V-shaped patterns as viewed from the downstream side in the rotation direction of the rotating body, and is substantially orthogonal to the rotation direction of the rotating body. A pair of the patterns arranged in the direction and adjacent to each other in a direction orthogonal to the rotation direction of the rotating body forms a preliminary discharge pattern offset in the rotation direction of the rotating body on the rotating body. .

  In the droplet discharge device according to the fifth aspect, the droplet discharge head performs preliminary discharge on the rotating bodies facing each other. And the droplet adhering on a rotary body is cleaned by the cleaning member which contacted the rotary body.

  Here, the droplet discharge head forms a preliminary discharge pattern, which is a pattern of droplets, on the rotating body during preliminary discharge. In this preliminary discharge pattern, a plurality of V-shaped patterns as viewed from the downstream side in the rotation direction of the rotator are arranged in a direction substantially orthogonal to the rotation direction of the rotator and in a direction orthogonal to the rotation direction of the rotator. A pair of adjacent patterns are offset in the rotation direction of the rotating body.

  In other words, since the V-shaped pattern formed by a plurality of droplets is formed with an interval in the direction orthogonal to the rotation direction of the rotating body, a pair adjacent to the direction orthogonal to the rotation direction of the rotating body. The plurality of droplets constituting the line of the line are not integrated.

  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 corresponding to the four colors, respectively, are arranged along the belt rotation direction. It is possible to record images.

  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 in the belt rotation direction, and the sheet P is separated 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 in the belt rotation direction. The belt cleaning unit 48 comes into contact with a portion of the transport belt 28 wound around the driving roll 24 and scrapes ink adhering to the transport belt 28, and a blade 49 as a cleaning member, and the blade 49 serves as a 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, the recording head 32 of each color performs ejection of ink droplets (hereinafter referred to as preliminary ejection) unrelated to image formation for the purpose of preventing nozzle clogging, etc. once every several seconds to several tens of seconds. Each time, several to several tens of shots are performed toward the conveyor belt 28.

  In each color recording head 32, a plurality of nozzles are arranged along a direction perpendicular to the belt rotation direction (hereinafter referred to as a belt width direction), and ink droplets are ejected from all the nozzles during preliminary ejection. Here, the ejection of ink droplets is not performed simultaneously from all the nozzles, but is performed by shifting the timing by a predetermined number.

  More specifically, first, ink droplets are ejected from the nozzles at intervals of several (for example, four) several (for example, four) at the same time, and then ink from the nozzles that are not ejected first. It is repeatedly performed a plurality of times (for example, three times) that droplets are ejected simultaneously. Thereby, at the time of preliminary ejection, as shown in FIG. 4A, a pattern P (hereinafter referred to as a preliminary ejection pattern) P by ink droplets attached to the transport belt 28 is formed.

  In this preliminary ejection pattern P, a plurality of straight lines L having a predetermined length L (several mm) made up of ink droplets I of several dots (for example, four dots as shown) arranged in the belt width direction are formed in the belt width direction. And a plurality of rows (for example, six rows as shown) are arranged in the belt rotation direction.

  Here, as shown in FIG. 4B, the plurality of straight lines L constituting each row are arranged at a predetermined interval L, and a pair of straight lines L adjacent in the belt width direction are arranged in the belt rotation direction. It is offset.

  For this reason, as shown in FIG. 4C, when the blade 49 cleans the ink droplet I, the ink droplets I of several dots constituting one straight line L become larger as a whole, but the belt width A pair of straight lines L adjacent to each other in the direction are offset in the belt rotation direction and are separated from each other so that the ink droplets I of several dots constituting the pair of straight lines L are not integrated with each other. The size of the ink droplet at the contact portion with the conveying belt 28 does not exceed a certain size.

  As a result, the ink droplets can be controlled so as not to expand excessively at the contact portion between the blade 49 and the conveyance belt 28, and the ink droplets are sized to flow down from the blade 49 without accumulating at the contact portion between the blade 49 and the conveyance belt 28. Therefore, it is possible to suppress ink from being accumulated at the contact portion between the blade 49 and the conveyance belt 28 as compared with the conventional case, and it is possible to suppress poor cleaning of the conveyance belt 28 by the blade 49.

  When the ink is water-based ink, the higher the water repellency of the transport belt 28 or the blade 49, the higher the fluidity of the ink on the blade 49. For this reason, by applying a liquid having water repellency such as silicone oil on the conveyance belt 28, it is possible to further suppress ink from being accumulated in the contact portion between the blade 49 and the conveyance belt 28.

  In the present embodiment, the plurality of straight lines L are arranged in a direction orthogonal to the belt rotation direction. However, if the same effect as that of the present embodiment is obtained, the direction in which the plurality of straight lines L are arranged is determined. Further, it may be inclined with respect to the direction orthogonal to the belt rotation direction.

  Next, a first modification of the preliminary ejection pattern P will be described.

  As shown in FIG. 5A, in the preliminary ejection pattern P, a plurality of dots (for example, 12 dots as shown) arranged in a direction inclined at a predetermined angle α (for example, 45 degrees) with respect to the belt width direction. A plurality of straight lines L having a predetermined length B (length in the belt rotation direction, for example, 5 mm) made of the ink droplets I are arranged in the belt width direction at a predetermined period A (for example, 5 mm), and the belt width direction A plurality of rows (for example, three rows as shown) are arranged in the belt rotation direction.

  When the preliminary ejection pattern P is formed, the recording head 32 simultaneously discharges several ink droplets (for example, two as shown in the figure) every few (for example, five as shown in the figure). By sequentially shifting the nozzles to be ejected one by one in the belt width direction, ink droplets are finally ejected several times from all the nozzles.

  Here, as shown in FIG. 5 (B), in each straight line L, several rows (for example, two dots as shown) of ink droplets I arranged in the belt width direction are several rows in the belt rotation direction ( For example, as shown in the figure, 6 rows) are arranged, and each row is shifted by one dot to one side in the belt width direction. Further, the plurality of straight lines L constituting each row are arranged offset in the belt width direction. Furthermore, each row is arranged at intervals in the belt rotation direction.

  For this reason, as shown in FIG. 5C, when the blade 49 cleans the ink droplet I, the integration of the ink droplets I of several dots starts with reference to a base point aligned with a predetermined period A in the belt width direction. Accordingly, the integrated ink droplets I of several dots are periodically arranged in the belt width direction. As a result, the ink droplets of several dots constituting a pair of straight lines L adjacent in the belt width direction are not integrated, and the size of the ink droplets is constant at the contact portion between the blade 49 and the conveying belt 28. It does not exceed the size.

  In other words, the ink droplets can be controlled so as not to expand excessively at the contact portion between the blade 49 and the conveyance belt 28, and the size should be such that the ink drops from the blade 49 without collecting at the contact portion between the blade 49 and the conveyance belt 28. Therefore, as compared with the conventional case, it is possible to suppress the accumulation of ink at the contact portion between the blade 49 and the conveyance belt 28, and it is possible to suppress poor cleaning of the conveyance belt 28 by the blade 49.

  The predetermined angle α, the predetermined period A, and the predetermined length B may be optimized as appropriate according to the viscosity of the ink, the water repellency of the conveyance belt 28, and the like. At this time, if the predetermined angle α is increased, the position of the integrated ink droplet I of several dots is stabilized, and the size of the integrated ink droplet is stabilized. On the other hand, when the predetermined angle α is reduced, the predetermined length B is shortened and the area of the preliminary discharge pattern is reduced, so that the preliminary discharge time can be shortened, and when performing the preliminary discharge during the image forming interval, Productivity can be improved.

  In the present embodiment, the plurality of straight lines L are arranged in a direction orthogonal to the belt rotation direction. However, if the same effect as that of the present embodiment is obtained, the direction in which the plurality of straight lines L are arranged is determined. Further, it may be inclined with respect to the direction orthogonal to the belt rotation direction.

  Next, a second modification of the preliminary ejection pattern P will be described.

  As shown in FIG. 6A, in this preliminary discharge pattern P, a line L ′ extending in a zigzag shape along the belt width direction is substantially parallel to a plurality of rows (for example, three rows as shown) in the belt rotation direction. Is arranged. The line L ′ has a configuration in which two types of straight lines L having different inclination directions with respect to the belt rotation direction are connected.

  For this reason, when the blade 49 scrapes the ink droplet I, as shown in FIG. 6B, the positions where the integration of the ink droplets I of several dots is arranged in the belt width direction at a predetermined cycle, and several dots The positions at which the integration of the ink droplets I ends are also arranged in the belt width direction at a predetermined cycle. Therefore, the position of the integrated ink droplet I of several dots at the contact portion of the blade 49 with the transport belt 28 is more stable than in the first modified example of the preliminary ejection pattern P described above.

  Further, since the ink droplets I of several dots constituting the pair of straight lines L can be collected at one place, it is effective when it is desired to make the ink droplet I integrated with several dots relatively large.

  Further, in the adjacent line L ′, the ink droplet I located closest to the other line L ′ in one line L ′ and the ink located in the most row from the other line L ′. Since the droplet I is shifted in the belt width direction, the integration of several dots of the ink droplet I of the line L ′ on the downstream side in the belt rotation direction and the number of dots of the line L ′ on the upstream side in the belt rotation direction are completed. The position where the integration of the ink droplets I starts is shifted in the belt width direction.

  For this reason, since several dots of ink droplets I constituting a pair of straight lines L adjacent to each other in the belt rotation direction are not integrated, as shown in FIG. A pair of adjacent ink droplets I in the belt rotation direction such as zero in the belt rotation direction between the ink droplet I positioned and the ink droplet I positioned closest to the other line L ′ of the other line L ′. It is possible to narrow the interval between the straight lines L. Accordingly, since the area of the preliminary ejection pattern P can be reduced, the preliminary ejection time can be shortened, and productivity can be improved when performing preliminary ejection during the image forming interval.

  In the present embodiment, the straight line L ′ is extended in the direction orthogonal to the belt rotation direction. However, if the same effect as in the present embodiment is obtained, the direction in which the straight line L ′ extends is determined. Further, it may be inclined with respect to the direction orthogonal to the belt rotation direction.

  Next, a third modification of the preliminary ejection pattern P will be described.

As shown in FIG. 7A, in this preliminary ejection pattern P, as in the first modification, a plurality of ink droplets I composed of several dots of ink droplets I arranged in a direction inclined at a predetermined angle with respect to the belt width direction. Are arranged in the belt width direction at a predetermined cycle, and a plurality of straight lines L arranged in the belt width direction are arranged in a plurality of rows (for example, three rows as shown) in the belt rotation direction. Here, as shown in FIG. 7B, the phase in the belt width direction of the straight lines L in adjacent rows is shifted to one side. For this reason, in adjacent rows, the ink droplet I located in the one row most than the other row and the ink droplet I located in the other row most in the other row have the belt width. The position where the integration of several dots of ink droplets I in the downstream row in the belt rotation direction ends, and the position where the integration of the ink droplets I of several dots in the upstream row in the belt rotation direction starts. Is shifted in the belt width direction.

  For this reason, the ink droplets I of several dots constituting a pair of straight lines L adjacent to each other in the belt rotation direction are not integrated, and as shown in the drawing, the ink droplet located in the most row in one row The interval between a pair of straight lines L adjacent to each other in the belt rotation direction can be reduced, for example, by zeroing the interval in the belt rotation direction between I and the ink droplet I located in the most other row in the other column. It becomes possible. Accordingly, since the area of the preliminary ejection pattern P can be reduced, the preliminary ejection time can be shortened, and productivity can be improved when performing preliminary ejection during the image forming interval.

  In the present embodiment, a plurality of straight lines L are arranged in a direction orthogonal to the belt rotation direction. However, the direction in which the plurality of straight lines L are arranged is within a range in which the same effect as in the present embodiment can be obtained. Further, it may be inclined with respect to the direction orthogonal to the belt rotation direction.

  Next, a fourth modification of the preliminary ejection pattern will be described.

  As shown in FIG. 8A, in this preliminary ejection pattern P, V-shaped patterns P ′ as viewed from the downstream side in the belt rotation direction are arranged in the belt width direction and arranged in the belt width direction. A plurality of rows (for example, six rows as shown) are arranged in the belt rotation direction.

  Here, a plurality of patterns P ′ constituting each row are arranged at a predetermined interval L, and a pair of patterns P ′ adjacent in the belt width direction are offset in the belt rotation direction.

  For this reason, as shown in FIG. 8B, as in the third modification described above, in the adjacent rows, the ink droplet I located closest to the other row in one row and the other The ink droplet I located in the first row among the rows is shifted in the belt width direction. As a result, the position at which the integration of several dots of ink droplets I in the row on the downstream side in the belt rotation direction ends and the position at which the integration of several dots of ink droplets I in the row on the upstream side in the belt rotation direction starts. Since they deviate in the belt width direction, the ink droplets I of several dots constituting a pair of straight lines L adjacent in the belt rotation direction are not integrated.

  In each row, V-shaped patterns P ′ are formed at intervals in the belt width direction, and the ink droplets I of several dots constituting a pair of patterns P ′ adjacent to each other in the belt width direction. Since the position where the integration is completed is separated in the belt width direction, the ink droplets I of several dots constituting a pair of patterns P ′ adjacent in the belt width direction are not integrated.

  In the present embodiment, the plurality of patterns P ′ are arranged in a direction orthogonal to the belt rotation direction. However, the direction in which the plurality of patterns P ′ are arranged is within a range in which the same effect as in the present embodiment can be obtained. Further, it may be inclined with respect to the direction orthogonal to the belt rotation 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. 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. 9 and 10, the ink jet recording apparatus 100 as a droplet discharge apparatus of 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 100 is a printer using a so-called offset printing method, and the recording head array 30 discharges 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 100 so that it can be inserted and removed. Sheets P are stacked on the sheet feed 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 by the pickup roll 18 to the downstream side in the transport direction, and the print 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 rollers 123 and 125 have a star wheel that is in contact with the surface to 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. 9, the recording head array 30 approaches the intermediate transfer drum 104 when ink droplets are ejected. Also, as shown in FIG. 10, the recording head array 30 secures a space for the maintenance unit 24 to enter the intermediate transfer drum 104 away from the intermediate transfer drum 104 during maintenance.

  As shown in FIG. 9, 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. Also, as shown in FIG. 10, the maintenance unit 34 enters the ejection area SE during non-image formation.

  Further, as shown in FIGS. 9 and 10, 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. 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. 11, a drum cleaning unit 148 is disposed on the downstream side in the drum rotation direction from the peeling claw 132 and on the upstream side in the drum rotation direction from the recording head array 30. The drum cleaning unit 148 contacts 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 FIGS. 12A and 13A, as in the first embodiment, the recording head 32 forms a preliminary ejection pattern P on the peripheral surface of the intermediate transfer drum 104 during preliminary ejection. To do. Accordingly, when the blade 49 cleans the ink droplet I by the blade 49 in FIG. 12B and FIG. 13B, the ink droplet I of several dots constituting one straight line L becomes larger integrally, but the belt It is separated from the ink droplets I of several dots constituting the straight line L adjacent in the width direction, and is not integrated with the ink droplets I of several dots forming the straight line L adjacent in the belt width direction. Therefore, the size of the ink droplet at the contact portion between the blade 49 and the intermediate transfer drum 104 does not exceed a certain size.

  That is, the ink droplets can be controlled so as not to expand excessively at the contact portion between the blade 49 and the intermediate transfer drum 104, and the ink droplets can flow from the blade 49 without collecting at the contact portion between the blade 49 and the intermediate transfer drum 104. Therefore, it is possible to suppress ink from being collected at the contact portion between the blade 49 and the intermediate transfer drum 104 and to prevent poor cleaning of the intermediate transfer drum 104 by the blade 49 as compared with the conventional case.

  In the first and second embodiments, the present invention has been described by taking an inkjet recording apparatus as an example. However, the present invention is not limited to an inkjet 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.

  Further, the “droplet discharge head” in the droplet discharge apparatus of the present invention includes a wide range of means for discharging droplets toward a recording medium or a rotating body. 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 rotating body.

  The “line” of the preliminary ejection pattern formed in the droplet ejection apparatus of the present invention includes a curved line in addition to a straight line.

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. (A) is a figure which shows the preliminary discharge pattern in the inkjet recording device of 1st Embodiment of this invention, (B), (C) is an enlarged view which shows the cleaning state of the ink droplet by a blade. (A) is a figure which shows the 1st modification of the preliminary discharge pattern shown to FIG. 5 (A), (B), (C) is an enlarged view which shows the cleaning state of the ink droplet by a blade. (A) is a figure which shows the 2nd modification of the preliminary discharge pattern shown to FIG. 5 (A), (B) is an enlarged view which shows the cleaning state of the ink droplet by a blade. (A) is a figure which shows the 3rd modification of the preliminary discharge pattern shown to FIG. 5 (A), (B) is an enlarged view which shows the cleaning state of the ink droplet by a blade. (A) is a figure which shows the 4th modification of the preliminary discharge pattern shown to FIG. 5 (A), (B) is an enlarged view which shows the cleaning state of the ink droplet by a blade. It is a side view which shows the outline of the inkjet recording device of 2nd Embodiment of this invention. It is a side view which shows the outline of the inkjet recording device of 2nd Embodiment of this invention. It is a side view which shows the outline of the printing part of the inkjet recording device of 2nd Embodiment of this invention. (A) is a figure which shows the preliminary discharge pattern in the inkjet recording device of 2nd Embodiment of this invention, (B) is an enlarged view which shows the cleaning state of the ink droplet by a blade. (A) is a figure which shows the preliminary discharge pattern in the inkjet recording device of 2nd Embodiment of this invention, (B) is an enlarged view which shows the cleaning state of the ink droplet by a blade.

Explanation of symbols

12 Inkjet recording device (droplet ejection 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)
P Preliminary discharge pattern L Straight line

Claims (5)

A droplet discharge head for discharging droplets;
A rotating body facing the droplet discharge head;
A cleaning member that contacts the rotating body and cleans the rotating body,
In the liquid droplet ejection head, a plurality of lines extending along a direction orthogonal to the rotation direction of the rotating body are arranged in a direction substantially orthogonal to the rotation direction of the rotating body during preliminary discharge, and the rotation A droplet discharge apparatus, wherein a pair of the lines adjacent to each other in a direction orthogonal to a rotation direction of the body forms a preliminary discharge pattern offset on the rotation direction of the rotation body on the rotation body. A droplet discharge head for discharging droplets;
A rotating body facing the droplet discharge head;
A cleaning member that contacts the rotating body and cleans the rotating body,
In the preliminary discharge, the droplet discharge head has a preliminary discharge pattern in which a plurality of lines inclined with respect to the rotation direction of the rotary body are arranged in a direction substantially orthogonal to the rotation direction of the rotary body. A droplet discharge device formed on the droplet discharge device.   3. The droplet discharge device according to claim 2, wherein the preliminary discharge patterns are arranged in a plurality of rows in a rotation direction of the rotating body and with a phase shifted in a direction orthogonal to the rotation direction of the rotating body. A droplet discharge head for discharging droplets;
A rotating body facing the droplet discharge head;
A cleaning member that contacts the rotating body and cleans the rotating body,
The liquid droplet ejection apparatus, wherein the liquid droplet ejection head forms a preliminary ejection pattern on the rotating body extending in a zigzag manner in a direction substantially orthogonal to the rotation direction of the rotating body during preliminary ejection. A droplet discharge head for discharging droplets;
A rotating body facing the droplet discharge head;
A cleaning member that contacts the rotating body and cleans the rotating body,
In the preliminary discharge, the droplet discharge head has a plurality of V-shaped patterns arranged in a direction substantially orthogonal to the rotation direction of the rotating body when viewed from the downstream side in the rotation direction of the rotating body, and the rotation A droplet discharge device, wherein a pair of the patterns adjacent to each other in a direction orthogonal to a rotation direction of the body forms a preliminary discharge pattern offset on the rotation direction of the rotation body on the rotation body.

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