Abstract:
A droplet ejection apparatus includes: a droplet ejection head that ejects droplets; a conveying member that retains a recording medium and conveys the recording medium with facing the recording medium to the droplet ejection head; a coating member that coats the conveying member with a coating liquid having a repellant property to the liquid ejected from the droplet ejection head; and a cleaning member that cleans the conveying member. The droplet ejection apparatus satisfies the following formulae 
       L3≧L1, L2≧L1   (1) 
     wherein, in a direction orthogonal to the conveying direction; L1 is the width of ink droplet ejecting of the droplet ejection head; L2 is the width of coating the coating liquid on the conveying member by the coating member; and L3 is the width of the cleaning of the conveying member by the cleaning member.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a droplet ejection apparatus that carries out cleaning of a member to which droplets that have been ejected from a droplet ejection head adhere, and to a cleaning method of a droplet adhered surface. 
         [0003]    2. Related Art 
         [0004]    If paper jams occur during printing in an inkjet printer serving as a droplet ejection apparatuses, then ink droplets are ejected from inkjet recording heads (droplet ejection heads) in a state in which there is no paper on the conveying belt (conveying member), and ink may be adhered to the conveying belt. Also, if dummy jetting, ejecting ink droplets that are not related to printing but undertaken in order to prevent blockages in unused nozzles, is carried out towards the conveying belt, then ink may adhere to the conveying belt. Therefore, it is necessary to create a cleaning device for cleaning ink adhered to the conveying belt. 
       SUMMARY 
       [0005]    A first aspect of the present invention provides a droplet ejection apparatus including: a droplet ejection head that ejects droplets; a conveying member that retains a recording medium and conveys the recording medium with facing the recording medium to the droplet ejection head; a coating member that coats the conveying member with a coating liquid, the coating liquid having a repellant property to the liquid ejected from the droplet ejection head; and a cleaning member that cleans the conveying member, the droplet ejection apparatus satisfying the following formulae (1) 
         [0000]      L3≧L1, L2≧L1   (1) 
         [0006]    wherein, in the formulae (1): L 1  is the width, in the direction orthogonal to the conveying direction, of the ink droplet ejecting of the droplet ejection head; L 2  is the width, in the direction orthogonal to the conveying direction, of coating the coating liquid on the conveying member by the coating member; and L 3  is the width, in the direction orthogonal to the conveying direction, of the cleaning of the conveying member by the cleaning member. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein: 
           [0008]      FIG. 1  is a side elevation showing the outline of an inkjet recording apparatus of a first exemplary embodiment of the present invention; 
           [0009]      FIG. 2  is a side elevation showing the outline of an inkjet recording apparatus of the first exemplary embodiment of the present invention; 
           [0010]      FIG. 3  is a side elevation showing a printing unit of an inkjet recording apparatus of the first exemplary embodiment of the present invention; 
           [0011]      FIG. 4  is an enlarged cross section showing a conveying belt provided in an inkjet recording apparatus of the first exemplary embodiment of the present invention; 
           [0012]      FIG. 5  is a diagram showing the relationship between the maximum printing width of a recording head L 1 , the coating width of an oil coating roll L 2 , and the cleaning width of a blade L 3  in an inkjet recording apparatus of the first exemplary embodiment of the present invention; 
           [0013]      FIG. 6  is a diagram showing the relationship between the paper width L 4 , the charging width of a charging roll L 5 , and the charge removing width of a charge removing roll L 6  in an inkjet recording apparatus of the first exemplary embodiment of the present invention; 
           [0014]      FIG. 7  is a side elevation showing the outline of an inkjet recording apparatus of a second exemplary embodiment of the present invention; 
           [0015]      FIG. 8  is a side elevation showing the outline of an inkjet recording apparatus of the second exemplary embodiment of the present invention; 
           [0016]      FIG. 9  is a side elevation showing a printing unit of an inkjet recording apparatus of the second exemplary embodiment of the present invention; 
           [0017]      FIG. 10  is an enlarged cross section showing an intermediate transfer drum provided in an inkjet recording apparatus of the second exemplary embodiment of the present invention; 
           [0018]      FIG. 11  is a diagram showing the relationship between the maximum printing width of a recording head D 1 , the coating width of an oil coating roll D 2 , and the cleaning width of a blade D 3  in an inkjet recording apparatus of the second exemplary embodiment of the present invention; 
           [0019]      FIG. 12  is a diagram showing the relationship between the cleaning width of the blade D 3 , and the paper width D 4  in an inkjet recording apparatus of the second exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Explanation will now be given of a first exemplary embodiment of the present invention, while referring to the diagrams. 
         [0021]    In  FIG. 1  is shown, as the liquid ejection apparatus of the present exemplary embodiment, an inkjet recording apparatus  12 . In the lower portion of the case  14  of the inkjet recording apparatus  12  is provided a paper supply tray  16 . The paper P stacked inside can be fed out one sheet at a time therefrom by a pick up roll  18 . The fed out paper P is conveyed along a conveying path  22  configured by plural conveying roller pairs  20 . 
         [0022]    Above the paper supply tray  16 , an endless conveying belt  28  is entrained around a driving roll  24 , and driven rolls  26 ,  27  and  29  as a conveying member. The driving roll  24  and the driven roll  26  are arranged in a substantially horizontal plane, and below these are arranged the driven rolls  27  and  29 , again arranged in a substantially horizontal plane. 
         [0023]    Further, above the conveying belt  28  is disposed a recording head array  30 , facing a flat portion  28 F of the conveying belt  28  between the driving roll  24  and the driven roll  26 . This opposing region is the ejection region SE where ink droplets are ejected from the recording head array  30 . Paper P conveyed on the conveying path  22  is held and supported on the conveying belt  28  to reach the ejection region SE, and, in a state of opposing the recording head array  30 , ink droplets from the recording head array  30  are adhered to the paper P according to image information. 
         [0024]    In the present exemplary embodiment the recording head array  30  is a rectangular shape having an effective recording region that is the width of the paper P or greater (the dimension of the paper P in the direction orthogonal to the conveying direction), and the recording head array  30  has four inkjet recording heads  32  arranged in the conveying direction as four droplet ejection heads (referred to below as recording heads). The corresponding colors thereof are yellow (Y), magenta (M), cyan (C), and black (K), and full color image recoding may be made therewith. 
         [0025]    Each of the recording heads  32  is driven by a head driving circuit (not illustrated). The head driving circuit, for example, is configured to determine the ejection timing of ink droplets according to the image information and the ink ejection aperture (nozzle) to be used, and sends a driving signal to the recording head  32 . 
         [0026]    The recording head array  30  may be immovable in the direction orthogonal to the conveying direction, but by structuring to be movable as the need arises, recording of a higher resolution may be made by image recording using multi-pass, and the influence of deficiencies in the recording head  32  on the recording result may be avoided. 
         [0027]    Four maintenance units  34 , corresponding to each of the recording heads  32 , are arranged at the sides of the recording head array  30 . As can be seen in  FIG. 2 , when maintenance is carried out on the recording heads  32 , the recording head array  30  is moved upward, and the maintenance units  34  are moved to enter into the space between the conveying belt  28  and the recording head array  30 . Then, in the state in which the nozzle face is opposing the maintenance units  34 , specific maintenance operations (such as suctioning, wiping, capping), are carried out. 
         [0028]    Further, ink tanks  35  that store inks of each of the colors are disposed above the recording head array  30 . Each of the ink tanks  35  are connected to its respective recording head  32 . 
         [0029]    As shown in  FIG. 3 , on the upstream side of the recording head array  30  a charging roll  36  connected to a power source  38  is disposed as a charging unit. The charging roll  36  sandwiches the conveying belt  28  and the paper P between itself and the driven roll  26 , and is driven, pressing the paper P onto the conveying belt  28 . At this time, since a specific voltage difference to that of the driven roll  26  is generated, charge may be applied to the paper P and paper P may be electrostatically attracted onto the conveying belt  28 . 
         [0030]    On the downstream side of the recording head array  30  is disposed a releasing scraper  40  that releases the paper P from the conveying belt  28 . The released paper P is conveyed by plural ejection roller pairs  42  configuring an discharge path  44  on the downstream side of the releasing scraper  40 , and discharged into an discharge paper tray  46  provided at the upper portion of the case  14 . 
         [0031]    Also, below the releasing scraper  40  is disposed a belt cleaning unit  48 . The belt cleaning unit  48  is provided with a blade  49  as a cleaning member, and a recovery box  51  into which is recovered ink and the like that is scraped off the conveying belt  28  by the blade  49 . The blade  49  contacts with a portion of the conveying belt  28  that is wrapped around the driving roll  24 , and scrapes off ink and the like that is adhered to the conveying belt  28 . An absorbent member  53  is spread out in the bottom portion of the recovery box  51 , and absorbs liquid that drops off from the blade  49 . 
         [0032]    On the downstream side of the belt cleaning unit  48  is disposed a grounded charge removal roll  62 , as a charge removal unit. The charge removal roll  62  sandwiches the conveying belt  28  between itself and the driven roll  27 , and is driven, removing the charge on the conveying belt  28 . 
         [0033]    An oil coating unit  64  and a back up plate  66  are provided between the driven roll  26  and the driven roll  27 , facing the conveying belt  28  therebetween. The oil coating unit  64  faces the outer peripheral surface of the conveying belt  28 , and the back up plate  66  contacts with the inner peripheral surface of the conveying belt  28 . 
         [0034]    The oil coating unit  64  is provided with: a case  68 ; an oil coating roll  70 , as a coating member, rotatably supported by the case  68 ; and an oil blade  72 , supported by the case  68 . The oil coating roll  70  is pressed by the back up plate  66  through the intervening conveying belt  28 , and rotated by being driven by the conveying belt  28 . Also, the oil coating roll  70  is formed of a porous body of polyethylene, urethane or the like, impregnated with silicone oil, and coats the conveying belt  28  with silicone oil. In contrast, the ink that is ejected from the recording heads  32  is a water based ink. Therefore, if ink adheres to the conveying belt  28  due to unnecessary ink ejection when there is a paper jam, or due to dummy jetting or the like ejecting ink onto the conveying belt  28 , then ink may be cohered by the water repellant effect of the film of silicone oil on the conveying belt  28 . Therefore, increase in the adhering force of the ink to the conveying belt  28  may be suppressed, and when cleaning the conveying belt  28  with the blade  49 , ink may be easily separated from the conveying belt  28 . 
         [0035]    Here, it is effective to always form a film of silicone oil on the conveying belt  28 , as in the present exemplary embodiment, so that dummy jetting may be carried out at short periods such as one time every several tens of seconds, in order to prevent increase in the viscosity of ink in the recording heads  32 . 
         [0036]    A driven roll may be used for the oil coating roll  70 . In such a case, slipping of the oil coating roll  70  relative to the conveying belt  28  may be prevented. 
         [0037]    The oil blade  72  contacts the conveying belt  28  at a position that is at the downstream side of the oil coating roll  70  in the rotation direction of the conveying belt  28 , and scrapes off excess silicone oil coated onto the conveying belt  28  to give a specific thickness of silicone oil film. The oil blade  72  may use rubber materials such as a flurorubber, NBR or the like, thin metal plate such as SUS (stainless steel) or the like, or resin films such as polyurethane, PET or the like. 
         [0038]    The bottom portion of the case  68  is covered with absorbent material  74  such as sponge, and this absorbent material  74  absorbs the silicone oil scraped off from the conveying belt  28  by the oil blade  72 . 
         [0039]    The conveying belt  28  may be formed of resins such as PET, PI, PA and the like, or rubber materials such as CR, NBR, HNBR, urethane rubber and the like, and coating treatment may be carried out on the surface thereof. Also, the blade  49  may be formed of rubber materials such as a flurorubber, NBR, HNBR or the like, thin metal plate such as SUS (stainless steel) or the like, or resin films such as polyurethane, PET or the like. Also, the roll portion of the oil coating roll  70  may be appropriately formed of a non-woven fabric formed from polyester, polyamide or the like, but as long as a predetermined amount of ink is able to penetrate therein, and wrapping around is possible, then other materials may be substituted. 
         [0040]    As mentioned above a silicone oil may be used as the liquid that is coated on the conveying belt  28  by the oil coating roll  70  (referred to below as coating liquid), and a water based ink may be used. Here, a coating liquid that repels the ink is appropriate, and for a water based ink, as well as a silicone oil, the following may be used: higher fatty acids, such as oleic acid, linoleic acid and the like; plasticizers such as dibutylphthalate, diisodecylphthalate, dibutylmaleate and the like; non water soluble alcohols such as n-decanol, dimethylbutanol and the like; and liquids that have water repellant properties such as fluoro oils, mineral oils, vegetable oils and the like. Also, for oil based inks, a liquid with high oil repellant properties may be used, such as water. 
         [0041]    Also, in order to stabilize the coating of the coating liquid on the conveying belt  28 , it is preferable that the dynamic viscosity of the coating liquid is in the range of 10 to 10 4  mm 2 /s, and more preferably in the range of 50 to 10 2  mm 2 /s. 
         [0042]    If the thickness of coating of the coating liquid is too thick, then the oil may penetrate into the paper P and this may lead to a detrimental effect on the quality of the image, such as the paper P repelling the ink and the like. On the other hand if the thickness of the coating of the coating liquid is too thin then the blade  49  may not be able to clean the ink effectively. It is, therefore, necessary to set the thickness of coating the coating liquid to within an appropriate range. An appropriate range for the coating thickness of the coating liquid is 1 nm to 20 μm. 
         [0043]    Also, it is necessary that the coating liquid is not volatile at room temperature. Specifically, the vapor pressure at 25° C. should be 13.33 Pa or less. Also, it is necessary that the coating liquid is not compatible with the ink. Specifically, the solubility to ink should be 0.1 wt % or less at room temperature (25° C.). 
         [0044]    It is necessary, also, so that the coating liquid wets out the conveying belt  28 , that formula (A) below is satisfied. Here, as shown in  FIG. 4 , the surface tension of the coating liquid T is designated γ o , and the critical surface tension of the conveying belt  28  is designated γ b . The critical surface tension is the surface tension, in the relationship of the solid surface contact angle θ to the surface tensions of various liquids, when cosθ is adjusted to 1 (that is when the contact angle of the liquid to the solid surface becomes 0°). In general, solid surfaces are well wetted by liquids that have a surface tension that is smaller than the critical surface tension of the surface. 
         [0000]      γ o &lt;γ b    (A) 
         [0045]    Further, in order for the coating liquid T to have water repellant properties it is necessary that the formula (B) below is satisfied. Here the surface tension of the ink I is designated γ i . 
         [0000]      γ o &lt;γ i    (B) 
         [0046]    By doing so, ink I does not wet out onto the surface of the film of coating liquid T, but coheres. In experimentation for evaluating the cleaning properties of a PET belt of critical surface tension γ b  of 43 [mN/m], as the conveying belt  28 , a silicon oil of a surface tension γ o  of 20 [mN/m], as the coating liquid, and water based ink with a surface tension γ i  of 30 [mN/m] as the ink, it is seen that there are no remnants of the ink on the conveying belt  28  and there is good cleaning. 
         [0047]    Here, in order that there is cleaning such that there are no droplets of ink remaining adhered to the conveying belt  28 , it is necessary that ink droplets ejected towards the conveying belt  28  from the recording head  32  always impact onto the film of silicone oil on the conveying belt  28 , and then also necessary that cleaning is carried out by the blade  49  for all of the ink droplets impacted onto the film of silicone oil. 
         [0048]    For this, as is shown in  FIG. 5 , the maximum value L 1  of the width, in the direction orthogonal to the conveying direction, of the ink droplet ejecting of the recording head  32  (referred to below as the maximum printing width), and the width L 2 , in the direction orthogonal to the conveying direction, of coating the silicone oil on the conveying belt  28  by the oil coating roll  70  (referred to below as the coating width), and the width L 3 , in the direction orthogonal to the conveying direction, of the cleaning of the conveying belt  28  by the blade  49  (referred to below as the cleaning width) should satisfy the formulae (1) below. The coating width L 2  is equivalent to the width, in the direction orthogonal to the conveying direction, of contact between the oil coating roll  70  and the conveying belt  28 , and the cleaning width L 3  is equivalent to the width, in the direction orthogonal to the conveying direction, of contact between the blade  49  and the conveying belt  28 . 
         [0000]      L3≧L1, L2≧L1   (1) 
         [0049]    By the coating width L 2  of the oil coating roll  70  being the same as or greater than the maximum printing width L 1  of the recording head  32 , there is the silicone oil film between the conveying belt  28  and all of the ink droplets on the conveying belt  28 , and increase may be prevented in the adhering force of all of the ink droplets on the conveying belt  28  to the conveying belt  28 . 
         [0050]    Also, by the cleaning width L 3  of the blade  49  being the same as or greater than the maximum printing width L 1  of the recording head  32 , cleaning is carried out by the blade  49  for all of the region in which ink droplets are adhered to the silicone oil film on the conveying belt  28 . Therefore, good cleaning of the conveying belt  28  may be carried out such that there are no remnants of the ink on the conveying belt  28 . In the present exemplary embodiment cleaning width L 3  and coating width L 2  are made wider than the maximum printing width L 1 . 
         [0051]    In order that it is certain that the cleaning by the blade  49  is carried out for all of the region in which ink droplets are adhered to the silicone oil film on the conveying belt  28 , it is preferable that the coating width L 2  of the oil coating roll  70  and cleaning width L 3  of the blade  49  satisfy the formula (2) below. 
         [0000]      L3≧L2   (2) 
         [0052]    By the cleaning width L 3  of the blade  49  being the same as or greater than the coating width L 2  of the oil coating roll  70 , not only is cleaning is carried out by the blade  49  for all of the region in which ink droplets are adhered to the silicone oil film on the conveying belt  28 , but also for all of the region of the silicone oil film on the conveying belt  28 . Therefore, there are no remnants of the ink on the conveying belt  28 , and there is good cleaning of the conveying belt  28 . In the present exemplary embodiment the cleaning width L 3  is wider than the coating width L 2 . 
         [0053]    In order to prevent soiling of the paper P due to ink mist adhering to the conveying belt  28 , it is necessary that the width L 4  of the paper P in the direction orthogonal to the conveying direction (referred to below as the paper width) and the cleaning width L 3  satisfy the following formula (3). 
         [0000]      L3≧L4   (3) 
         [0054]    By the cleaning width L 3  being the same as or greater than the paper width L 4 , ink mist adhered in the region of contact between the paper P and the conveying belt  28  is completely scraped off by the blade  49 , and so soiling of the paper P by ink mist adhered to the conveying belt  28  may be prevented. 
         [0055]    In order to convey the paper P stably with the conveying belt  28 , as shown in  FIG. 6 , it is necessary that width L 4  of the paper P in the direction orthogonal to the conveying direction (referred to below as the paper width) and the width L 5  in the direction orthogonal to the conveying direction that the charging roll  36  charges the conveying belt  28  (referred to below as the charging width) satisfy the formula (4) below. The charging width L 5  of the charging roll  36  is equivalent to the width, in the direction orthogonal to the conveying direction, of contact of the charging roll  36  with the conveying belt  28 . 
         [0000]      L5≧L4   (4) 
         [0056]    By the charging width L 5  of the charging roll  36  being the same or greater than the paper width L 4 , the whole width of the paper P may be electrostatically attracted onto the conveying belt  28 , and the paper P may be stably conveyed by the conveying belt  28 . In the present exemplary embodiment the charging width L 5  is wider than the paper width L 4 . 
         [0057]    If there is a region where no charge removal is carried out by the charge removal roll  62  on the conveying belt  28 , then in such a region, dust adherence and sparking may occur. Also, the electrostatic attraction between such a region and the recording heads  32  can increase abnormally, and contact may occur between the recording heads  32  and the conveying belt  28 . 
         [0058]    It is preferable, therefore, that the charge on the conveying belt  28  is completely removed by the charge removal roll  62 , and so it is necessary that the charging width L 5  of the charging roll  36  and the width L 6 , in the direction orthogonal to the conveying direction, of the removal of the charge from the conveying belt  28  by the charge removal roll  62  (referred to below as the charge removal width) satisfies the formula (5) below. 
         [0000]      L6≧L5   (5) 
         [0059]    By the charge removal width L 6  of the charge removal roll  62  being the same as or greater than the charging width L 5  of the charging roll  36 , charge may be removed from all of the region of the conveying belt  28  that is charged by the charging roll  36 , and various problems that are caused by charge remaining on the conveying belt  28  may be suppressed. In the present exemplary embodiment the charge removal width L 6  is wider that the charging width L 5 . 
         [0060]    Next explanation will be given of a second exemplary embodiment. Structures that are similar to those of the first exemplary embodiment will be allocated the same numerals and explanation thereof will be omitted. 
         [0061]    As shown in  FIG. 7  and  FIG. 8 , the ink jet recording apparatus  100 , as a droplet ejection apparatus of the present exemplary embodiment, is a full color printer for forming a full color image on paper P with four colors of ink, yellow (Y), magenta (M), cyan (C), and black (K). The ink jet recording apparatus  100  is a printer using an offset method, and by ejecting ink towards an intermediate transfer drum  104  as a holding member (carrier), first forms an ink image on the intermediate transfer drum  104 , and then transfers the ink image from the intermediate transfer drum  104  to the paper P. 
         [0062]    At a lower portion of ink jet recording apparatus  100  is provided a removable paper supply tray  16 . Paper P is stacked in the paper supply tray  16 , and the uppermost of paper P is in contact with a pick up roll  18 . Paper P may be supplied one sheet at a time by the pick up roll  18  at the downstream side of the conveying direction, and supplied to an image forming unit  122  by pairs of conveying rolls  109 ,  120 ,  121 ,  123 , and  125  disposed in the above order along a conveying path. The rolls of conveying rolls  123 ,  125  that contact the face of paper P to which the ink image is transferred are star wheels. 
         [0063]    In the image forming unit  122  the intermediate transfer drum  104  is disposed facing the conveying path, and a recording head array  30  is disposed above the intermediate transfer drum  104 , and maintenance units  34  are also disposed in the vicinity of the recording head array  30 . 
         [0064]    The recording head array  30 , as shown in  FIG. 7 , is in the vicinity of the intermediate transfer drum  104  when ejecting ink. Also, as shown in  FIG. 8 , when maintaining, the recording head array  30  is distanced from the intermediate transfer drum  104  and a space between the recording head array  30  and the intermediate transfer drum  10  for inserting the maintenance units  34  may be secured. 
         [0065]    Also, as shown in  FIG. 7 , the maintenance units  34 , when forming an image, recede to the outside of the ejection region SE where ink droplets are ejected from the recording head array  30 . And, as shown in  FIG. 8 , when not forming an image, the maintenance units  34  are introduced into the ejection region SE. 
         [0066]    Further, as shown in  FIGS. 7 and 8 , contacting the intermediate transfer drum  104  at the conveying path side, are a charging roll  128  as a transfer unit, a charge removing roll  130  as a transfer unit, and a releasing scraper  132 , in that order from the upstream side in the conveying direction. The charging roll  128  presses the paper P against the intermediate transfer drum  104  and applies a charge to the paper P, and the paper P is attracted by electrostatic attraction to the intermediate transfer drum  104 , and an ink image is transferred to the paper P. Further, the charge removing roll  130  conveys the paper P while removing the charge from the paper P, and releases the electrostatic attraction between the paper P and the intermediate transfer drum  104 . Then, the releasing scraper  132  releases the paper P from the intermediate transfer drum  104 . 
         [0067]    Then, downstream in the conveying direction of the releasing scraper  132 , are disposed conveying roll pairs  127 ,  129 ,  131 ,  133 ,  135 ,  137 , and  139 , in that order from the upstream side in the conveying direction. 
         [0068]    The conveying rolls of the conveying roll pairs  127 ,  133 ,  135 ,  137 , and  139  that contact the face of the paper P on which the ink image has been transferred are star wheels, and contact with the face of the paper P on which the ink image has been transferred is reduced. 
         [0069]    Above the ink tanks  35  is disposed a discharge tray  46 , and at the side of the discharge tray  46  is disposed the conveying roller pair  139 . The paper P is ejected into the discharge tray  46  by the conveying roller pair  139 . 
         [0070]    As shown in  FIG. 9 , a drum cleaning unit  148  is disposed further to the downstream side in the rotation direction of the intermediate transfer drum  104  than the releasing scraper  132  and further to the upstream side in the rotation direction of the intermediate transfer drum  104  than the recording head array  30 . This drum cleaning unit  148  is equipped with a blade  49  as a cleaning unit which contacts the peripheral surface of the intermediate transfer drum  104 , scrapes off ink and the like that has not been transferred to the paper P and remains on the intermediate transfer drum  104 ; and a recovery box  51  that recovers the ink and the like that has been scraped off from the intermediate transfer drum  104  by the blade  49 . An absorbent member  53  is spread out at the bottom of the recovery box  51 , and liquid that drips down from the blade  49  is absorbed thereby. 
         [0071]    Also, an oil coating unit  164  is disposed further to the downstream side in the rotation direction of the intermediate transfer drum  104  than the blade  49  and further to the upstream side in the rotation direction of the intermediate transfer drum  104  than the recording head array  30 . The oil coating unit  164  is provided with a case  68  and an oil coating roll  70 , as a coating unit, rotatably supported by the case  68 . The oil coating roll  70  is pressed by the intermediate transfer drum  104 , and rotated by being driven by the intermediate transfer drum  104 . Also, the oil coating roll  70  is formed of a porous body of polyethylene, urethane or the like, impregnated with silicone oil, and coats the intermediate transfer drum  104  with silicone oil. In contrast, the ink that is ejected from the recording heads  32  is a water based ink. Therefore, ink may be cohered by the water repellant effect of the film of silicone oil on the intermediate transfer drum  104 . Therefore, increase in the adhering force of the ink to the intermediate transfer drum  104  may be suppressed, and, when cleaning the intermediate transfer drum  104  with the blade  49 , ink may be easily separated from the intermediate transfer drum  104 . 
         [0072]    A driving roll may be used for the oil coating roll  70 . In such a case slipping of the oil coating roll  70  relative to the intermediate transfer drum  104  may be prevented. 
         [0073]    It is necessary that formula (A) below is satisfied, so that the coating liquid wets out the intermediate transfer drum  104 . Here, as shown in  FIG. 10 , the surface tension of the coating liquid T is designated γ o  and the critical surface tension of the intermediate transfer drum  104  is designated γ b . 
         [0000]      γ o &lt;γ b    (A) 
         [0074]    Further, in order for the coating liquid T to have water repellant properties it is necessary that the formula (B) below is satisfied. Here the surface tension of the ink I is designated γ i . 
         [0000]      γ o &lt;γ i    (B) 
         [0075]    By doing so, as in the first exemplary embodiment, ink I does not wet out onto the surface of the film of coating liquid T, and the ink coheres and becomes easier to scrape off from the intermediate transfer drum  104  by the blade  49 . 
         [0076]    Here, in order that there is cleaning such that there are no droplets of ink remaining adhered to the intermediate transfer drum  104 , first it is necessary to ensure that ink droplets ejected towards the intermediate transfer drum  104  from the recording head  32  always impact onto the film of silicone oil on the intermediate transfer drum  104 , and then also necessary to ensure that that cleaning is carried out by the blade  49  for all of the ink droplets impacted onto the film of silicone oil. 
         [0077]    For this, as is shown in  FIG. 11 , the maximum value D 1  of the width, in the direction orthogonal to the conveying direction, of the ink droplet ejecting of the recording head  32  (referred to below as the maximum printing width), and the width D 2 , in the direction orthogonal to the conveying direction, of coating the silicone oil on the intermediate transfer drum  104  by the oil coating roll  70  (referred to below as the coating width), and the width D 3 , in the direction orthogonal to the conveying direction, of the cleaning of the intermediate transfer drum  104  by the blade  49  (referred to below as the cleaning width) should satisfy the formulae (6) below. The coating width D 2 , is equivalent to the width, in the direction orthogonal to the conveying direction, of contact between the oil coating roll  70  and the intermediate transfer drum  104 , and the cleaning width D 3  is equivalent to the width, in the direction orthogonal to the conveying direction, of contact between the blade  49  and the intermediate transfer drum  104 . 
         [0000]      D3≧D1, D2≧D1   (6) 
         [0078]    By the coating width D 2  of the oil coating roll  70  being the same as or greater than the maximum printing width D 1  of the recording head  32 , there is the silicone oil film between all of the ink droplets on the intermediate transfer drum  104  and the intermediate transfer drum  104  itself, and increase may be prevented in the adhering force of all of the ink droplets on the intermediate transfer drum  104  to the intermediate transfer drum  104 . 
         [0079]    Also, by the cleaning width D 3  of the blade  49  being the same as or greater than the maximum printing width D 1  of the recording head  32 , cleaning is carried out by the blade  49  for all of the region in which ink droplets are adhered to the silicone oil film on the intermediate transfer drum  104 . Therefore, good cleaning of the intermediate transfer drum  104  may be carried out such that there are no remnants of the ink on the intermediate transfer drum  104 . In the present exemplary embodiment cleaning width D 3  and coating width D 2  are made wider than the maximum printing width D 1 . 
         [0080]    In order that it is certain that the cleaning by the blade  49  is carried out for all of the region in which ink droplets are adhered to the silicone oil film on the intermediate transfer drum  104 , it is preferable that the coating width D 2  of the oil coating roll  70  and cleaning width D 3  of the blade  49  satisfy the formula (7) below. 
         [0000]      D3≧D2   (7) 
         [0081]    By the cleaning width D 3  of the blade  49  being the same as or greater than the coating width D 2  of the oil coating roll  70 , not only is cleaning is carried out by the blade  49  for all of the region in which ink droplets are adhered to the silicone oil film on the intermediate transfer drum  104 , but also for all of the region of the silicone oil film on the intermediate transfer drum  104 . Therefore, there are no remnants of the ink on the intermediate transfer drum  104 , and good cleaning of the intermediate transfer drum  104  may be carried out. In the present exemplary embodiment the cleaning width D 3  is wider than the coating width D 2 . 
         [0082]    As shown in  FIG. 12 , in order to prevent soiling of the paper P due to ink mist adhering to the intermediate transfer drum  104 , it is necessary that the width D 4  of the paper P in the direction orthogonal to the conveying direction (referred to below as the paper width) and the cleaning width D 3  satisfy the following formula (8). 
         [0000]      D3≧D4   (8) 
         [0083]    By the cleaning width D 3  being the same as or greater than the paper width D 4 , ink mist adhered in the region of contact between the paper P and the intermediate transfer drum  104  is completely scraped off by the blade  49 , and so soiling of the paper P by ink mist adhered to the intermediate transfer drum  104  may be prevented. 
         [0084]    In the first and second exemplary embodiments ink jet recording apparatuses have been explained as examples of the present invention, however the invention is not limited to ink jet recording apparatuses, and may be applied to various industrial applications for general droplet ejection apparatuses such as: manufacturing of color filters for display use, by ejecting coloration ink onto polymer films; forming EL display panels by carrying out ejecting of organic EL liquid solutions onto substrates, and the like. 
         [0085]    Also, for the “recording medium” for image recording in the droplet ejection apparatus of the invention, all objects and materials on which droplets may be ejected by a droplet ejection head are included. Therefore, while the recording medium of course may be recording paper and OHP sheets and the like, it also includes other objects and materials such as, for example, polymer films. 
         [0086]    For the “droplet ejection head” of the droplet ejection apparatus of the present invention, all ejectors that eject droplets towards a recording medium or holding member are included. For example, ink jet recording heads that are smaller in length than the width of the paper P and that eject ink droplets by moving in the width direction of the paper P, and the like are included. 
         [0087]    For the “conveying member” of the droplet ejection apparatus of the present invention, all members that retain and convey a recording medium are included. For example, drums that retain a recording medium on the peripheral surface thereof and rotate, and reciprocating tables that retain a recording medium and, and the like are included. 
         [0088]    For the “conveying unit” of the droplet ejection apparatus of the present invention, all conveyers that contact a recording medium to a holding member and convey are included. For example, conveying rolls that nip and convey a recording medium, and the like are included. 
         [0089]    For the “holding member (carrier)” of the droplet ejection apparatus of the present invention, all members that carry liquid ejected from a droplet ejection head are included. For example, rotating belts on which droplets are carried, and the like are included. 
         [0090]    For the “cleaning members” of the droplet ejection apparatus of the present invention, all members that clean droplets adhered to conveying members are included. For example, cleaning rolls that contact the conveying member and rotate absorbing the droplets, and movable blades that contact the conveying member and move in a direction that intersects with the conveying direction, and the like are included. 
         [0091]    For the “cleaning unit” of the droplet ejection apparatus of the present invention, all cleaners that clean droplets adhered to the holding member are included. For example, cleaning rolls that contact the holding member and rotate absorbing the droplets, and movable blades that contact the conveying member and move in a direction that intersects with the conveying direction, and the like are included. 
         [0092]    For the “coating members” of the droplet ejection apparatus of the present invention, all members that coat onto a conveying member a coating liquid with repellant properties to the droplets ejected from the droplet ejecting head are included. Included, for example, are: droplet ejection heads that eject such a coating liquid towards a conveying member; webs that are impregnated with such a coating liquid and contact with the conveying member; rolls that retain such a coating liquid on the surface thereof, contact with the conveying member and rotate; and rolls that are impregnated with, or retain such a coating liquid on the surface thereof, contact with the conveying member and move in a direction that intersects with the conveying direction. 
         [0093]    For the “coating unit” of the droplet ejection apparatus of the present invention, all devices for coating onto a holding member a coating liquid with repellant properties to the droplets ejected from the droplet ejecting head are included. Included, for example, are: droplet ejection heads that eject such a coating liquid towards a holding member; webs that are impregnated with such a coating liquid and contact with the holding member; rolls that retain such a coating liquid on the surface thereof, contact with the holding member and rotate; and rolls that are impregnated with, or retain such a coating liquid on the surface thereof, contact with the holding member and move in a direction that intersects with the conveying direction. 
         [0094]    For the “charging unit” of the droplet ejection apparatus of the present invention, all devices for charging a conveying member are included. For example, corotrons that carry out non-contact charging of the conveying member are included. 
         [0095]    Further, for the “charge removing unit” of the droplet ejection apparatus of the present invention, all devices for removing charge from a conveying member are included. For example, charge removing lamps that remove charge from the conveying member are included. 
         [0096]    The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The exemplary embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.