JP2006264893A - Ink jet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably and surely remove washing liquid, foreign matter, ink, or liquid of the mixture of them which are adhered on a electrifying/adsorbing carrying surface of a sheet member as a recorded member, and thereby to maintain high speed printing quality, particularly in an ink jet type image forming device. <P>SOLUTION: During recording operation to the sheet member, a washing liquid absorber 23 supplies the washing liquid to a web 31 to impregnate the web with the washing liquid, and the web 31 is brought into slide-contact with the carrying surface of a carrying belt 1 to wipe off the attached liquid, foreign matters, ink, or the liquid of the mixture of them adhered on the carrying surface to clean the surface. A rubber blade 41 disposed downstream of the absorber gathers the liquid 48 or the like adhered on the carrying surface. After completion of the recording operation, the rubber blade 41 is retracted and separated from the carrying surface. In synchronization with the retraction, the carrying belt 1 moves backward in a direction opposite to the movement in the recording operation to return the liquid 48 which is gathered downstream to the web 31, and then the liquid is wiped off by the web 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus of an ink jet recording system that forms an image on a recording material such as paper (hereinafter referred to as a sheet material) by ejecting ink from a recording head.

  In general, in an image forming apparatus, in order to accurately determine the position of an image formed on a sheet material and to prevent the image from being stretched and contracted due to a difference in image magnification, the print quality is not impaired. Until then, accurate conveyance of the sheet material is required. In the case of a color image forming apparatus, a color shift due to a shift between images appears, so that highly accurate conveyance of the sheet material is particularly required. With the goal of high-accuracy conveyance, conventionally, the conveyance surface of an endless conveyance belt is charged and the sheet material is adsorbed by electrostatic attraction force, so that the recording surface becomes an image forming unit (consisting of a photosensitive drum or a recording head). On the other hand, a transport system that transports the head toward an accurate position is well known. In this case, the traveling speed of the conveyance belt is maintained with high accuracy, and the sheet material is in close contact by charging adsorption without shifting or floating on the conveyance surface.

  In the ink jet recording apparatus, the sheet material is charged and adsorbed and transported as described above, so that the initial ink discharge characteristics of the recording head can be stabilized or the speed of the recording process can be customized with priority. In such a case, so-called preliminary ejection is performed in which ink is ejected onto the conveyance belt in advance. However, such preliminary discharge ink not only hinders the sheet material from being charged and adsorbed on the conveyance surface of the conveyance belt, but also adheres to the back surface of the sheet material and impairs the print quality.

  By the way, in the electrification adsorption structure on the conveyance surface of such a sheet material, the surface of the conveyance belt is used as an insulator to give a charge to the sheet material. However, if conductive ink adheres to the conveyance surface, the electric resistance of the conveyance surface Decreases, and the adsorptive power to the sheet material decreases due to leakage of electric charge. As a result, there is a problem that the sheet material is lifted or the like and hits the recording head, or hits the transfer guide member or the like, thereby causing conveyance failure and leading to image shift or color shift.

  In order to solve this problem, the ink jet recording apparatus previously proposed by the applicant of the present application stably cleans the charge adsorption conveyance surface of the conveyance belt and reduces the conveyance load during image formation to increase the conveyance speed. By maintaining a constant accuracy, expansion and contraction due to image shift is suppressed, and a good print quality with no color shift is obtained (see Patent Document 1).

  As another proposal by the applicant of the present application, a liquid having an electric resistance value higher than the electric resistance value of the ink is used to prevent a conveyance failure due to a decrease in electrostatic adsorption force, and the charging adsorption conveyance surface is efficiently cleaned by the cleaning member. Thus, there is an ink jet recording apparatus that improves image quality (see Patent Document 2).

  Further, the present applicant's proposal is also related to the cleaning technology for the charged adsorption conveyance surface. The ink adsorbed on the conveyance belt is absorbed by the absorbent material, and the ink absorbed by the absorbent material is absorbed by the ink suction means. There is an ink jet recording apparatus in which suction is performed, a cleaning liquid is applied to a conveying surface by a cleaning liquid application unit, and the cleaning liquid is supplied from a cleaning liquid supply unit. In this case, before the ink preliminarily ejected on the conveyor belt is dried and fixed, the ink is wiped off to maintain the print quality (see Patent Document 3).

Japanese Patent No. 2867167 Japanese Patent No. 2873879 JP 2000-127362 A

  By the way, in each technique of the above-mentioned patent document proposed with the goal of improving the image quality and the print quality, the following points are desired to be improved.

  In the case of Patent Document 1, the ink scraping blade and the ink absorbing member are used to remove and clean the ink attached to the conveying surface. However, considering the removal of the ink attached to the blade member and the ink absorbing member, It is necessary to prevent the cleaning performance from deteriorating. In addition, when the blade member or ink absorbing member is in a dry state, it is difficult to completely remove the ink that has adhered to the transport surface and dried, and the reliability of the device is eliminated by wiping such problems. Need to be increased.

  In Patent Document 2, the conveyor belt is cleaned using a cleaning member such as a felt, a porous member, cloth, or paper impregnated with a liquid having an electric resistance higher than that of ink such as silicon oil. In that case, a means for refreshing the cleaning member itself to which ink or paper powder adheres after repeated use over a long period of time so as not to deteriorate the cleaning performance is required.

  Further, in Patent Document 3, it is necessary to devise such that the cleaning liquid does not hang down on the transport surface even when the cleaning liquid is excessively supplied. One technique for increasing the processing capability by high-speed recording is to shorten the conveyance interval between the preceding sheet material and the succeeding sheet material as much as possible. In order to bring the ink absorber into contact with the conveying surface of the conveying belt instead of the sheet material, the ink absorber is moved up and down in a short period of time, moved away from the conveying surface, and retreated or approached. Necessary for each passage of material. As described above, when a device or mechanism corresponding to a high-speed repetitive operation is provided, a new problem is posed such that stable operation over a long period of time is required and generation of operation noise needs to be suppressed to a low level.

  In view of the above, the object of the present invention is to stably and surely remove the cleaning liquid, foreign matter and ink adhering to the charge adsorption conveyance surface of the sheet material which is a recording material, and the mixed liquid material to achieve high print quality. An object of the present invention is to provide an image forming apparatus of an ink jet recording system that can be maintained.

  In order to achieve the above object, a typical ink jet recording apparatus of the present invention ejects ink from a recording head to form an image on a recording surface of a recording material and perform recording. In order to convey the sheet material by regulating the position, an endless suction conveyance member provided with a conveyance surface that adsorbs the sheet material by charging, and a cleaning unit that removes the liquid material adhering to the conveyance surface are provided. Is a roll sheet-like web that is drawn out so as to be in sliding contact with the conveyance surface of the adsorption conveyance member and wipes off the liquid material adhering to the conveyance surface; And a liquid material wiping means for wiping the liquid material adhering to the transport surface disposed so as to be able to contact and separate from the downstream transport surface, and transporting the web at the end of the recording operation The liquid material wiping means is moved away from the conveyance surface while being in a sliding contact state, and the suction conveyance member is reversely moved in the direction opposite to that during the recording operation. It is.

  Therefore, in the ink jet recording apparatus having the above configuration, during the recording operation, the cleaning liquid supply means supplies the cleaning liquid to the web to be impregnated, and the web is slidably contacted with the conveying surface so that the cleaning liquid, foreign matter and ink attached to the conveying surface, or The liquid mixed with them is wiped off and cleaned. At the same time, the liquid material wiping means collects the liquid material adhering from the conveying surface on the downstream side. After the recording operation is finished, the liquid material wiping means is retracted from the conveying surface and separated. By the retreating operation, the liquid material scraped by the liquid material wiping means stays at the position on the transport surface. In substantially the same manner, the suction conveyance member is reversely moved in the direction opposite to that during the recording operation. Then, the liquid material scraped off on the downstream side returns to the web and is wiped off by the web.

  According to the ink jet recording apparatus of the present invention, during the recording operation, the sheet material is transported toward the recording head on the transport surface of the suction transport member, and the ink, cleaning liquid, foreign matters, etc. adhering to the transport surface are liquidized with the downstream web. By wiping by both the object wiping means and reversing the conveying surface in the opposite direction at the end of the recording operation, the liquid material collected by the liquid wiping means is reversed and wiped again by the web. . By removing the liquid material adhering to the transport surface stably and effectively by such two-stage removal operation, the back surface of the recording material is not soiled, and the electrostatic chucking force due to static electricity on the transport surface does not decrease. An image with excellent print quality can be obtained without causing a conveyance failure.

  Next, a preferred embodiment of the ink jet recording apparatus according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the ink jet recording apparatus of the present embodiment can be broadly divided into a sheet material conveying system for conveying a sheet material that is a recording material and a belt cleaning system. In the sheet material conveyance system, a conveyance belt (adsorption conveyance member) 1 that adsorbs and conveys a sheet material to a conveyance surface with static electricity is wound around a roller of a driving roller 2 and a driven roller 3 and stretched by a tension roller 4. Tension is applied from the inside of the belt so that the conveyor belt 1 does not relax.

  On the other hand, the belt cleaning system performs printing by ejecting ink from a print head (recording unit) outside the figure based on image information on the sheet material conveyed in the left direction indicated by the arrow in the figure. A plurality of full-line heads 6 to 11 are held on the print head frame to constitute a full-line multi-head system, and a belt cleaning unit (cleaning means) 5 for wiping off and cleaning ink adhering to the conveying belt 1 is provided. Has been.

  In such a belt cleaning system, the print head frame that holds the full line heads 6 to 11 can be moved up and down in the vertical direction by a drive motor (not shown). A cap unit (not shown) is disposed in the space between the conveyance belt 1 and the full line heads 6 to 11, and when printing is not performed, the cap unit moves away from the conveyance belt 1 and retreats upward. Then, the individual line heads are capped and closed so that the nozzles of the full line heads 6 to 11 are not dried. Further, the full line heads 6 to 11 improve the printing quality by promoting yellow (Y), cyan (C), magenta (M), and AMM (ink fixing from the upstream side in the sheet conveying direction indicated by the arrow of the conveying belt 1. Ink to be used: print quality improving liquid) and black (K1, K2) toners in order.

  As shown in FIG. 1, the belt cleaning unit 5 is attached in parallel along the rotational axis of the drive roller 2. As shown in FIG. 2 and FIG. 3 as viewed obliquely from below, the roll sheet-like web 31 is made of a non-woven fabric whose surface is impregnated with a surfactant to improve the liquid absorption capability, and the full line heads 6-11. The width of the print belt is wider than the width of the print belt 1 and narrower than the width of the conveyor belt 1, and the leading end and the trailing end are bonded to the winding cores 32 and 33, respectively. At the start of use, most of the web 31 is wound around the winding core 33. Power is transmitted from a driving source (not shown) to rotate the winding core 32, so that the running direction of the conveyor belt 1, that is, the sheet material. The web 31 is caused to travel in the direction opposite to the conveyance direction. The web 31 is wound between the web pressing roller 21 and the support shaft 25 to collect and remove foreign matters such as paper dust on the conveyor belt 1, and the foreign matter does not flow downstream from the web 31. To prevent. The web 31 is also made of a material that does not generate rubbing powder or the like due to friction with the conveyor belt 1 and can absorb the cleaning liquid without flipping it. As long as the web 31 is made of a material having resistance to ink, the web 31 is not limited to the non-woven fabric having high liquid absorption capability used in the present embodiment.

  Next, as shown in FIGS. 4 and 5, the web pressing roller 21 is formed in a cylindrical shape, an absorbent groove 22 is provided at one side of the side, and a cleaning liquid supply groove 26 is provided at the bottom. ing. The cleaning liquid supply groove 26 communicates with a cleaning liquid supply port 24 provided at one end of the web pressing roller 21. A tube (not shown) is connected to the cleaning liquid supply port 24 so that the cleaning liquid can be supplied to the cleaning liquid supply groove 26. Further, as shown in FIG. 5, a cleaning liquid absorber (cleaning liquid supply means) 23 is fitted into the absorber groove 22, and the end surface of the cleaning liquid absorber 23 is absorbed so as to slightly protrude from the cylindrical side surface of the web pressing roller 21. The depth of the body groove 22 and the size of the cleaning liquid absorber 23 are determined. The cleaning liquid absorber 23 is an absorbent body made of a polyurethane porous body and needs to have liquid absorption and ink resistance. In this embodiment, the product name Ruby Cell (manufactured by Toyo Polymer) is used. Yes. The cleaning liquid absorber 23 is not limited to such a material as long as it has liquid absorbency and resistance to ink.

  In addition, the present inventors tried to use the product name ruby cell as described above for the cleaning liquid absorber 23 for the following reason. A polyurethane porous body that has ink resistance and is used as an optimal material for an ink absorber is excellent in the ability to suck liquids such as ink and water when it absorbs water moderately. However, the present inventors have found that the polyurethane porous body in a completely dried state repels liquid such as water and ink on the surface, and cannot exhibit the original liquid absorbing ability. In such a state where the ink absorber made of the polyurethane porous body is completely dried, the ink on the conveyor belt 1 is transferred to the ink absorber even if the ink adhering to the surface of the conveyor belt 1 is removed. It is hardly absorbed and remains on the conveyor belt 1. Further, even when the cleaning liquid is supplied to the ink absorber made of a completely porous polyurethane porous body, the liquid is not immediately absorbed. Accordingly, a partially dried state remains in the incomplete liquid absorption state, and a portion where the ink on the transported ink 1 cannot be sucked remains.

  In order to solve such a problem, the inventors once brought the whole into a water-absorbing state by supplying a large amount of water to a polyurethane porous body used as a cleaning liquid absorber. Thereafter, the amount of water absorbed by the absorber was reduced by sucking the water with a pump, and an attempt was made to clean the surface of the conveyor belt 1 in a state where the liquid absorption capability was increased. For example, when performing high-speed recording such as 60 sheets per minute on an A4 size sheet material, the transport belt 1 is used even when water is supplied to and sucked into the ink absorber to increase liquid absorption. It was found that when the ink absorber was brought into contact with the ink absorber at a high speed of about 300 mm / s, there was an effect of drawing out the cleaning liquid slightly remaining in the ink absorber. That is, even if the ink absorber has a liquid absorbing force in a normal state, when it comes into contact with the surface of the transport belt 1 that travels at a high speed, the cleaning liquid that remains slightly in the ink absorber is attached to the surface of the transport belt 1. As a result, it turned out that the method is not suitable for high-speed recording.

  Therefore, the web pressing roller 21 is again provided with a cleaning liquid receptacle 35 on its lower surface side, and serves as a tray that prevents the cleaning liquid that has not been absorbed by the cleaning liquid absorber 23 from overflowing into the apparatus. A discharge port 36 for discharging the cleaning liquid accumulated in the cleaning liquid receiver 35 is provided on the bottom surface of the cleaning liquid receiver 35 and is connected to a waste liquid tank through a tube (not shown).

  6 to 9 sequentially show the operation of the belt cleaning unit 5. The web pressing roller 21 is rotatable in such a manner that the cleaning liquid absorber 23 can be rotated so that a position where the cleaning liquid absorber 23 faces the conveying belt 1 (FIG. 6) and at least two positions (FIG. 9) which face the cleaning liquid receiver 35 can be taken. Installed in. Further, as shown in FIGS. 6, 7, and 8, the cleaning liquid receiver 35 is located at a position away from the surface so that the web pressing roller 21 can rotate, and the peripheral portion of the cleaning liquid receiver 35 and the web. The pressing roller 21 is mounted in the cleaning unit 5 so as to be positioned at each of the positions where the cylindrical side surface of the pressing roller 21 contacts (FIG. 9). With such a configuration, when the printing operation is not performed, the cleaning liquid absorber 23 is sealed by the cleaning liquid receiver 35 to prevent drying of the absorbed cleaning liquid and suppress consumption of the cleaning liquid.

  Further, the web facing plate 71 facing the web pressing roller 21 on the opposite side of the conveying belt 1 is in surface contact with the back surface of the conveying belt 1 to prevent the conveying belt 1 from flapping. Further, the elasticity of the cleaning liquid absorber 23 slightly protruded from the roller surface of the web pressing roller 21 supports the pressing of the web 31 against the conveying belt 1.

  Further, in the belt cleaning unit 5, as shown in FIG. 10, the rubber blade (liquid wiping means) 41 disposed on the downstream side of the web pressing roller 21 in the traveling direction of the conveyance belt 1 is used to place the belt cleaning unit 5 on the conveyance belt 1. Liquid material is wiped away. The rubber blade 41 made of an elastic member such as urethane rubber has a thickness dimension of about 1.5 mm and is a plate shape having a width slightly narrower than the width dimension of the web 31. The rubber blade 41 is bonded and bonded to the presser plate 45 and is sandwiched between the blade base 40 and the presser plate 45. After adjusting the height with the screw 46, the blade base 40 with the screw 44 is used. Fixed to. The left and right ends of the blade base 40 are fixed by screws 47 to a rotation support plate 43 that is rotatably supported at one end with respect to the support shaft 25. Further, the rotation support plate 43 is connected to a rotation drive source (not shown), and the rubber blade 41 is shown in the position (FIG. 6) when performing the operation of wiping off the liquid on the conveyor belt 1 and in each figure after FIG. The liquid 48b adhering on the rubber blade 41 is movable between two positions, the position for absorbing and removing the liquid 48b by the liquid absorbing body 42.

  If the liquid absorbent body 42 is provided as a refresh member in the present invention to remove the liquid material adhering to the rubber blade 41, the wiping end of the rubber blade 41 is always kept clean and functions sufficiently. It is effective in making it exhibit, and it can comprise as another embodiment.

  Such a liquid absorber 42 is slightly longer than the rubber blade 41 so as to be able to contact the entire tip of the rubber blade 41, and is a polyurethane porous body like the cleaning liquid absorber 23. It is necessary to have. For this reason, the product name Ruby Cell (manufactured by Toyo Polymer) is used in this embodiment. Further, the liquid absorber 42 is not limited to such a material as long as it has liquid absorbency and resistance to ink. Further, the liquid absorbing body 42 is rotatably supported by the support member so that it can move to two positions (FIGS. 6 and 8) in accordance with the rotation of the rubber blade 41. As a result, the rubber blade 41 comes into contact with the transport belt 1 and wipes off the liquid 48 adhering to the transport belt 1. When the contact from the conveyor belt 1 is released, the liquid 48 scraped by the rubber blade is split and the liquid 48b adhering to the tip of the rubber blade 41 is absorbed by the liquid absorber 42 and removed. When the liquid wiping operation on the conveyor belt 1 is not performed, the tip of the rubber blade 41 is always kept clean.

  Further, the blade facing plate 72 facing the rubber blade 41 on the opposite side of the conveying belt 1 is fixed to the frame so as to come into contact with the back surface of the conveying belt 1 in the same manner as the web facing plate 71. Therefore, the conveyance belt 1 is sandwiched. Therefore, even if the conveyor belt 1 rotates at a high speed, the conveyor belt 1 is prevented from fluttering, and the liquid material in which the ink adhering to the conveyor belt 1 and the cleaning liquid are mixed is reliably removed. Preventing the flapping of the transport belt 1 is very important in that accurate transport can be realized when the sheet material is transported by being charged and adsorbed on the transport surface, and the position of the transport surface is regulated. It leads to that.

  Next, the operation of ejecting ink from the plurality of full line heads 6 to 11 to form and record a color image on the sheet material is performed as follows.

  When the ink jet recording apparatus is not used for a long time, the ink in the nozzles may be dried and fixed, resulting in non-ejection. In order to prevent this, the nozzle surface is capped and closed to prevent drying. Further, even when the cap is attached, it is left unused for a long time, or before the printing operation, the ink is pushed out from the nozzle by a pump, or a recovery operation is performed in which negative pressure is applied from the cap to suck the ink from the nozzle. Thereafter, a wiping operation for wiping off ink remaining on the nozzle surface (alternate wiping to the left and right) is performed, and after ink droplets are completely removed from the nozzle surface, a printing operation on the sheet material is started. Even after printing on the sheet material is started, not all nozzles eject ink depending on the recorded image, and there are nozzles that eject ink and nozzles that do not eject ink. When printing on multiple sheets of material continuously, there is no problem with the nozzle that ejects the ink, but if the nozzle that did not eject ink during printing for each of the multiple sheets ejects ink for the first time, the first In the case of several firings, the ink moisture in the nozzles decreases due to evaporation and the viscosity of the ink increases. It may be done. It is known that the occurrence of such non-ejection and twisting returns to the normal state after several inks are ejected. Therefore, before actually printing on the sheet material, several to several tens of preliminary ejection operations are issued to places other than the sheet material, and printing on the sheet material is performed in a normal ejection state.

  Therefore, in the present embodiment, a preliminary discharge operation is performed between the sheet materials on the conveying belt 1 so as not to decrease the recording speed and the processing capacity. A preliminary discharge operation is performed on the conveying belt 1 for each sheet material or once for each of a plurality of sheet materials, approximately 10 times from all nozzles of all the full line heads 6 to 11.

  If the ink on the conveyance belt 1 discharged in the preliminary discharge operation is left as it is, not only ink stains adhere to the back surface of the sheet material, but also the surface resistance on the conveyance belt 1 decreases. As a result, the adsorption force that adsorbs the sheet material by static electricity is reduced, and the printing quality is lowered when the conveyance speed varies unevenly. In order to prevent this, the ink discharged onto the conveyor belt 1 is removed by the belt cleaning unit 5 attached to the downstream side of the conveyor belt 1. The operation is shown below.

  That is, as shown in FIG. 9, the belt cleaning unit 5 when the recording operation is not performed prevents the cleaning liquid absorber 23 from being dried in a state where the cleaning liquid absorber 23 is sealed by the cleaning liquid receiver 35. At that time, the cleaning liquid absorber 23 is maintained in the sucked state. At the same time, the rubber blade 41 is located at a position where it does not contact the conveyor belt 1, and the liquid absorber 42 is located at a position where it does not contact the rubber blade 41.

  When recording image information, a signal is transmitted from a host device such as a personal computer or a host computer to the control unit of the ink jet recording apparatus. The rubber blade 41 is moved to a position where the tip of the rubber blade 41 contacts the conveyor belt 1 by a driving source. Further, the cleaning liquid receiver 35 is moved in a direction away from the cleaning liquid absorber 23 by the vertical movement mechanism (not shown) of the cleaning liquid receiver, and at the same time, the web pressing roller 21 is rotated by the rotation mechanism (not shown). It rotates to a position facing the conveying belt 1 via the web 31. At that time, the cleaning liquid absorbed in the cleaning liquid absorber 23 is supplied from the front end of the cleaning liquid absorber 23 to the web 31, and the cleaning liquid is also supplied to the portion of the web 31 that contacts the transport belt 1. The rubber blade 41 is in a state where the tip of the rubber blade 41 is in contact with the conveyor belt 1.

  When the conveyance belt 1 is driven to run at the start of the recording operation, in this embodiment, for example, if image formation at a recording speed of 60 sheets per minute is customized on an A4 sheet material, the belt moving speed corresponding thereto is set. For example, it is set to 318 mm / s. At this time, the distance between the trailing edge of the preceding sheet material on the conveying belt 1 and the leading edge of the succeeding sheet material is set to 108 mm, for example. In the case where a recording operation for a plurality of sheets is continuously performed, a preliminary discharge operation is performed on the conveyance surface of the conveyance belt 1 between the preceding sheet material and the succeeding sheet material at intervals of 108 mm. Depending on the environment in which the ink jet recording apparatus is installed, this preliminary ejection operation is performed 10 times for each sheet of the sheet material, for example, in an environment where it is easy to dry at high temperature and low humidity, or when the viscosity of ink is high at low temperature. Do about. In a normal office environment, for example, if the room temperature is 25 ° C. and the humidity is about 50%, about 5 preliminary recording operations may be performed once every 5 sheets.

  When the image-recorded sheet material is peeled off from the conveyance belt 1 and the ink discharged onto the conveyance belt 1 passes through the belt cleaning unit 5, a part of the ink is absorbed by the web 31. However, most of the ink is left on the conveyor belt 1 by mixing with the drawn cleaning water when the web 31 supplied with a cleaning liquid mainly composed of water contacts the conveyor belt 1 that moves at high speed. The amount of washing water at this time is several times to several tens of times the amount of ink on the conveyor belt 1. The ink diluted with a large amount of washing water is wiped off from the conveying belt 1 by the rubber blade 41 on the downstream side of the web pressing roller 21, and as shown by the liquid 48 in FIG. After being scraped and collected at the contact portion of the rubber blade 41, most of the liquid flows down below the rubber blade 41 and flows into a waste liquid receiver (not shown) disposed under the rubber blade 41. At this time, a part of the liquid remains at the contact portion between the conveyance belt 1 and the rubber blade 41 even when the conveyance belt 1 continues to rotate, and the liquid does not reach the downstream side of the rubber blade 41.

  When there is no cleaning liquid on the transport belt 1 and only ink is present, the amount is very small. For this reason, even in a short time during which the ink is transported from the discharge position to the cleaning position, the water in the ink evaporates and sticks onto the transport belt 1, and the ink is completely removed by the rubber blade 41 alone. It is difficult to wipe off. The inventors supply a cleaning liquid to the ink on the transport belt 1 to greatly reduce the ink concentration, thereby allowing even the ink on the transport belt 1 moving at a high speed of 318 mm / s to be a rubber blade. 41, it was found that it can be wiped off. Therefore, even when the next succeeding sheet material is adsorbed to the portion where the ink is ejected by the preliminary ejection operation, it is possible to avoid the deterioration of the print quality due to the back contamination of the sheet material or the adsorption failure.

  Thus, after the series of recording operations is completed, the conveying belt 1 is stopped after being rotated one or more times without conveying the sheet material. The liquid adheres to the conveyor belt 1 only from the web pressing roller 21 to the rubber blade 41 to which the liquid drawn from the web 31 by the high speed rotation of the conveyor belt 1 adheres. Thereafter, as shown in FIG. 7, the rubber blade 41 is operated so as to be separated from the position in contact with the transport belt 1. At that time, the liquid 48 remaining in the contact portion between the conveyance belt 1 and the rubber blade 41 is separated into a liquid 48 a remaining on the conveyance belt 1 and a liquid 48 b adhering to the tip of the rubber blade 41.

  Thereafter, as shown in FIG. 8, the liquid absorbing body 42 rotates and contacts the tip of the rubber blade 41, and absorbs and removes the liquid 48 b attached to the tip of the rubber blade 41. At the same time, the conveyor belt 1 runs in the reverse direction to the printing operation indicated by the arrow in FIG. 8 at a speed of about ¼ that is slower than the printing operation speed. If the traveling speed of the conveyor belt 1 is ¼ of the printing speed, all the liquid on the conveyor belt 1 can be absorbed by the web 31 and the cleaning liquid absorber 23 therebelow. As a result, the web pressing roller, which is the portion where the liquid on the conveyor belt 1 is adhered, including the liquid 48a where the conveyor belt 1 and the rubber blade 41 are in contact with each other, where the most liquid remains. All the liquid in the region from 21 to the rubber blade 41 is removed. When the portion to which the liquid 48a is attached on the conveyor belt 1 passes the position of the web pressing roller 21, the reverse travel of the conveyor belt 1 is stopped. Thereby, all the liquid on the conveyance belt 1 is removed.

  In FIG. 9 again, the liquid suction body 42 is rotated from the position where it contacts the rubber blade 41, and at the same time, the web pressing roller 21 is rotated to the position shown in the figure, and the cleaning liquid receiver 35 is raised. In this state, an appropriate amount of cleaning liquid is supplied from the port 24 so that the cleaning liquid absorber 23 has sufficiently absorbed the cleaning liquid. The cleaning liquid that has not been absorbed is all collected in the cleaning liquid receiver 35 and therefore does not leak into the apparatus. Moreover, the cleaning liquid absorber 23 is hermetically sealed by raising the cleaning liquid receiver 35. As a result, the absorbed cleaning liquid is not evaporated and the cleaning liquid absorber 23 is not dried. In this state, a print standby state is entered.

  After the printing operation is completed, the rubber blade 41 is retracted from the conveyance belt 1 and the conveyance belt 1 is made to travel backward by a fixed distance at a speed that is 1/4 of the rotation speed during printing. The portion of the liquid 48a that has been in contact with the liquid can be absorbed by the web 31 and removed. However, if left as it is, the rubber blade 41 remains in contact with the conveyance belt 1, so that the liquid 48 wiped from the conveyance belt by the rubber blade 41 is in contact with the conveyance belt 1 and the rubber blade 41. It will remain in the part. If left in that state for a long time, the water in the liquid evaporates and only the solid content remains. If this happens, the conveyor belt 1 and the rubber blade 41 may adhere to each other and the conveyor belt 1 may not rotate when the conveyor belt 1 is rotated next time. In addition, the back surface of the sheet material is stuck on the conveyance belt 1 or the front end of the rubber blade 41, and the front end of the rubber blade 41 cannot be completely contacted with the conveyance belt 1 by the sticking ink, and is partially wiped off. However, it is conceivable that the back surface of the sheet material is stained by leaving the liquid on the transport belt 1. In the present embodiment, at the time when one printing operation is completed, the liquid remaining on the conveyor belt 1 and the liquid adhering to the rubber blade 41 are removed every time. There will be no defects.

  Further, when a large number of sheet materials are conveyed by long-term use, foreign matters such as paper dusts coming out of the sheet material are also accumulated on the conveying belt 1. When foreign matter such as paper dust reaches the rubber blade 41, the mixed liquid of ink and cleaning liquid easily slips out of the rubber blade 41 at that portion. For this reason, in this embodiment, the web 31 is disposed on the upstream side of the rubber blade 41 for the purpose of removing foreign matters such as paper dust, and after a certain number of sheet materials are conveyed, the core metal 32 is rotated, A portion where the foreign matter such as paper dust is brought into contact with the conveyance belt 1 is taken up, and the new surface is operated so as to contact the conveyance belt 1. In this embodiment, every time 1000 sheets of the sheet material are conveyed, the web 31 is operated so as to be fed out by about 5 mm. Thereby, the influence of foreign matters such as paper dust can be eliminated, and the adhering to the conveyance belt 1 can be performed more stably. The ink can be cleaned.

  In addition, the liquid used as the cleaning liquid in this embodiment is pure water that is also used as the main component of the ink. Furthermore, in this embodiment, the absorber is used to remove the liquid adhering to the rubber blade 41. However, any other material may be used as long as it removes the liquid adhering to the rubber blade 41. For example, it is possible to use a second blade member for scraping off the liquid adhering to the tip of the rubber blade, or to blow off the liquid at the tip of the rubber blade by air blowing.

  Thus, the ink preliminarily ejected from the full line heads 6 to 11 and adhered to the conveyance belt 1 is surely wiped off by the rubber blade 41, and the end of the rubber blade 41 does not contact the conveyance belt 1 at the end of the printing operation. After moving to the position, the conveyor belt 1 and the rubber blade 41 are rotated by reversely rotating the conveyor belt 1 by a certain distance and absorbing and removing the liquid adhering to the tip of the rubber blade 41 by contacting the absorber 42. There is no possibility of sticking and movement, or sticking as sticking ink on the conveying belt 1 or the tip of the rubber blade 41, and recording sheet back surface contamination not occurring at the next printing.

(Second Embodiment)
Next, FIG. 11 shows an ink jet recording apparatus according to the second embodiment.

  In the second embodiment, the cleaning liquid for cleaning the predischarge ink discharged on the conveyance belt 1 is several times to several tens of times the predischarge ink on the conveyance belt 1 by the seventh full line head 12. This amount is discharged and supplied onto the conveyor belt 1.

  As in the first embodiment, the cleaning unit 5 has a web 31 and a rubber blade 41 disposed downstream thereof, and a web facing plate 71 and a blade facing plate 72 are disposed so as to face each other with the conveying belt 1 interposed therebetween. . The rubber blade 41 is disposed so as to be able to be separated / contacted with respect to the conveyor belt 1, and the absorber 42 is disposed so as to be able to be separated / contacted with respect to the rubber blade 41. Since the web roller 21 does not need to supply the cleaning liquid as in the first embodiment, a cleaning liquid absorber, a port for supplying the cleaning liquid, and the like are not necessary. That is, the entire roller is pressed against the web facing plate 71 by a spring (not shown) in order to surely press the conveying belt 1 against the web facing plate 71 with a roller for simply winding the web 31. . In addition, the operation after printing is the same as that of the first embodiment, that is, the operation of moving the rubber blade 41 and the liquid absorber 42 and the operation of causing the conveyor belt 1 to travel backward by a predetermined distance.

  In the second embodiment, not only the same effect as in the first embodiment can be obtained by the above configuration, but also the cleaning liquid can be supplied only when the preliminary discharge operation is performed. It becomes possible. In addition, the supply amount can be accurately measured, and the supply amount of the cleaning liquid can be significantly reduced by supplying the necessary minimum amount. In addition, the ink and the cleaning liquid discharged on the transport belt 1 are: Some are absorbed by the web 31, but most of them reach the rubber blade 41 by the high speed rotation of the conveyor belt 1 and are removed there. The full line head 12 that supplies the cleaning water only needs to have the cleaning liquid spread over the entire width of the rubber blade 41. Therefore, even if there is some non-ejection, there is not much problem, and the full line head 12 is normally a defective product. Even a line head can be used, and the cost of the apparatus is not significantly increased.

  In the second embodiment, the full line head used for actual printing is used to supply the cleaning liquid. However, the present invention is not limited to this as long as the cleaning liquid can be supplied. A plurality of short-length inkjet heads may be provided. Further, since the purpose is to supply the cleaning liquid, an ink jet head having a large discharge amount capable of supplying more cleaning liquid may be used. When an inkjet head with a larger discharge amount is used, the number of ejections when supplying the same amount of cleaning liquid can be reduced, and the life of the inkjet head for supplying the cleaning liquid can be extended. A spray nozzle that sprays fine droplets of the cleaning liquid in a line shape can also be used.

(Third embodiment)
Next, the third embodiment can be configured as follows.

  In the first embodiment, immediately after the end of one printing operation, the movement operation of the rubber blade 41, the reverse rotation operation of the transport belt 1, and the operation of absorbing and removing the liquid adhering to the rubber blade 41 by the liquid absorber 42 are performed. In this embodiment, the rubber blade 41, the transport belt 1, and the liquid sucking body 42 are not operated immediately after the end of one printing operation, but are performed after a certain time. Further, when the next printing operation command is issued within such a fixed time, the normal printing operation is performed as it is without performing the operations of the rubber blade 41, the conveyor belt 1 and the liquid suction body 42. Since the liquid 48 accumulated in the contact portion between the conveyor belt 1 and the rubber blade 41 is kept within a short time of about 5 to 15 minutes, the moisture is hardly evaporated, so that the liquid 48 is transported for the printing operation as it is. Even if the belt 1 is rotated, no sticking or wiping failure occurs. The time during which no operation is performed after printing can be automatically set longer or shorter depending on the environment (temperature, humidity) in which the apparatus is installed.

  As is clear from each of the above-described embodiments, the printing operation is continuously performed by performing the operations of the rubber blade 41, the conveying belt 1, and the liquid absorber 42 after a certain time has elapsed after the end of one printing operation. When there is an instruction to perform printing, it is not necessary to perform the movement of the rubber blade 41, the reverse rotation of the conveying belt 1 and the movement of the liquid sucking body 42 between the printing operations, so that the printing waiting time is shortened. In addition, it is possible to achieve a reduction in operation sound and an improvement in device reliability associated with reducing the number of operations.

  The present invention is not limited to the above embodiments, and other embodiments and combinations thereof are possible as long as they do not depart from the gist of the present invention. Application examples and modifications thereof are also possible. Examples are also possible.

  For example, in each of the first to third embodiments, the cleaning means is mainly composed of the web 31 and the rubber blade 41 as the liquid wiping means. On the other hand, as described above, a structure in which the liquid absorbing body 42 is provided as a refresh member that removes the liquid adhering to the rubber blade 41 can be configured as the fourth embodiment.

1 is a perspective view showing a configuration of a first embodiment of an ink jet recording apparatus according to the present invention. The perspective view explaining the composition of the belt cleaning unit in a 1st embodiment. The perspective view explaining the structure of the belt cleaning unit of 1st Embodiment similarly. The perspective view which shows the roller for web pressing of the 1st Embodiment. The perspective view which shows the roller for web pressing from another angle. Sectional drawing which shows operation | movement of the belt cleaning unit in the 1st Embodiment. Sectional drawing which shows operation | movement of the belt cleaning unit in the 1st Embodiment. Sectional drawing which shows operation | movement of the belt cleaning unit in the 1st Embodiment. Sectional drawing which shows operation | movement of the belt cleaning unit in the 1st Embodiment. The perspective view which shows the rubber blade in the said 1st Embodiment. The perspective view which shows the structure of 2nd Embodiment of the inkjet recording device by this invention.

Explanation of symbols

1 Conveying belt (adsorption conveying member)
5 Belt cleaning unit (cleaning means)
6-12 Full line head (recording means)
21 Web pressing roller 23 Cleaning liquid absorber (liquid supply means)
31 Web 41 Rubber blade (liquid wiping means)
42 Refreshing member 48 Liquid material

Claims (21)

In an inkjet recording apparatus that records and records an image on a recording surface of a recording material by discharging ink from a recording head.
An endless suction conveyance member provided with a conveyance surface for adsorbing the recording material by charging in order to regulate and convey the position of the recording surface with respect to the recording head;
Cleaning means for removing the liquid material adhering to the transport surface;
The cleaning means comprises
A roll sheet-shaped web that is drawn out so as to be in sliding contact with the conveyance surface of the suction conveyance member and wipes off the liquid material adhering to the conveyance surface;
Cleaning liquid supply means for supplying and impregnating the cleaning liquid to the web;
Liquid material wiping means disposed so as to be able to contact and separate from the transport surface downstream of the cleaning liquid supply means, and for wiping the liquid material attached to the transport surface;
Contains
At the end of the recording operation, the liquid material wiping means is retracted away from the transport surface while keeping the web in sliding contact with the transport surface, and the suction transport member is opposite to that during the recording operation. An inkjet recording apparatus configured to run backward in a direction. 2. The ink jet recording apparatus according to claim 1, wherein the suction conveyance member is caused to travel backward in the opposite direction at a speed slower than that during the recording operation. 2. The ink jet recording apparatus according to claim 1, wherein at the end of the recording operation, the suction conveyance member is caused to travel backward in a direction opposite to that during the recording operation by a distance equal to or greater than a distance between the web and the liquid material wiping unit. . 3. The ink jet recording apparatus according to claim 2, wherein the suction conveyance member is caused to travel backward in the opposite direction at a speed slower than that during the recording operation by a distance equal to or greater than a distance between the web and the liquid material wiping means. Inkjet recording device. The ink jet recording apparatus according to claim 1, wherein the suction conveyance member is reversely moved at the end of one recording operation. 6. The ink jet recording apparatus according to claim 5, wherein the suction conveyance member is reversely moved after a predetermined time has elapsed since one recording operation is completed. 7. The ink jet recording apparatus according to claim 6, wherein when the next recording operation is performed after a lapse of a predetermined time after one recording operation is completed, the reverse conveyance of the suction conveyance member is stopped. apparatus. The ink jet recording apparatus according to claim 1, wherein the cleaning liquid supply unit includes a cleaning liquid absorber. 9. The ink jet recording apparatus according to claim 8, wherein the cleaning liquid absorber is porous. 10. An ink jet recording apparatus according to claim 1, wherein an ink jet head is used as the cleaning liquid supply means. The inkjet recording apparatus according to claim 10, wherein the inkjet head is the same as the inkjet head used during printing. 12. The ink jet recording apparatus according to claim 11, wherein the ink jet head has a larger discharge amount than the ink jet head used during printing. The ink jet recording apparatus according to claim 1, wherein the cleaning liquid supplied from the cleaning liquid supply unit is water. 14. The ink jet recording apparatus according to claim 1, wherein the liquid material wiping means is a plate-like elastic member that makes one side slidably contact the transport surface. 15. The ink jet recording apparatus according to claim 14, wherein the liquid material wiping means is capable of contacting and separating from the transport surface. 16. The ink jet recording apparatus according to claim 15, further comprising a refresh member for removing the liquid material adhering to the liquid material wiping means. 17. The ink jet recording apparatus according to claim 16, wherein the refresh member is operable in a direction in which the refresh member is engaged with and disengaged from a wiping end of the liquid material wiping means. 18. The inkjet recording apparatus according to claim 1, wherein each time the recording operation is completed, the suction conveyance member reversely travels in the opposite direction, and the liquid material wiping means is attached by the refresh member. An ink jet recording apparatus, wherein a liquid removal operation is performed. 19. The ink jet recording apparatus according to claim 18, wherein a predetermined time elapses between the reverse movement of the suction conveyance member in the opposite direction and the removal operation to the liquid material wiping means by the refresh member every time one recording operation is completed. And an ink jet recording apparatus. 20. The ink jet recording apparatus according to claim 19, wherein the reverse movement of the suction conveyance member in the opposite direction and the removal operation to the liquid material wiping means by the refresh member are performed for a certain period of time after one recording operation is completed. An ink jet recording apparatus, wherein a recording operation is stopped when a next recording operation is performed before elapses. In an inkjet recording apparatus that records and records an image on a recording surface of a recording material by discharging ink from a recording head.
An endless suction conveyance member provided with a conveyance surface for adsorbing the recording material by charging in order to regulate and convey the position of the recording surface with respect to the recording head;
Cleaning means for removing the liquid material adhering to the transport surface;
The cleaning means comprises
Cleaning liquid supply means for supplying a cleaning liquid to the transport surface;
Liquid material wiping means disposed so as to be able to contact and separate from the transport surface downstream of the cleaning liquid supply means, and for wiping the liquid material attached to the transport surface;
A refresh member for removing the liquid material adhering to the liquid material wiping means;
An ink jet recording apparatus comprising: