JP2009034931A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer which can secure a drying time of papers long without a conveyance speed of papers being decreased. <P>SOLUTION: A drying unit U6 is configured to blow a drying air towards the downstream side in a paper conveyance direction for print papers P1 and P2 after image printing, and also to blow the blown drying air out of a housing 6 via a vent part 46c of a discharge roller 46 and a discharge opening 47 of the housing 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet printer.

  Conventionally, as a means for printing characters and images (hereinafter collectively referred to simply as “images”), inkjet printers that print by reciprocating a print head that ejects ink in the width direction of the paper have been known. It has been.

  Here, if the paper after printing the image is stacked on the discharge tray in a state where the ink is not yet dried, the ink on the paper will not be dried uniformly and the printed image will be uneven in color or overlapped. Since problems such as ink adhering to the back side of the combined paper occur, it is necessary to sufficiently dry the paper and load it on the discharge tray.

Patent Document 1 discloses an infrared heater that dries ink landed on paper after image printing with thermal energy, and an air nozzle that blows air onto the surface of the paper heated by the infrared heater to lower the temperature. Inkjet printer technology including the above is disclosed.
JP 2001-270089 A

  However, in conventional ink jet printers, ink is dried only on the surface facing the infrared heater during paper transport. Therefore, in order to obtain the required drying capacity, the paper faces the infrared heater. Have to lengthen the time. That is, there is a problem in that the paper conveyance speed has to be slowed, and the processing capacity of the printer is reduced.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an ink jet printer that can ensure a long drying time of paper without reducing the paper conveyance speed. is there.

  In order to achieve the above-described object, in the present invention, the drying air is blown toward the downstream side in the paper transport direction with respect to the paper after image printing by the drying means.

  Specifically, the present invention is directed to an inkjet printer that prints an image on paper by ejecting ink from the print head onto the paper, and has taken the following solutions.

That is, the invention of claim 1 includes a housing having the print head and a discharge port for discharging the paper after image printing to the outside.
A drying chamber provided on a transport path downstream in the paper transport direction from the print head in the housing, and having an exhaust port communicating with the discharge port;
Drying means for blowing a drying air for drying the paper into the drying chamber;
The drying means blows dry air toward the downstream side in the paper transport direction on the paper after image printing, and the blown dry air passes through the exhaust port of the drying chamber and the discharge port of the housing. It is configured to blow out of the casing.

  In this manner, the drying means blows the drying air toward the downstream side in the paper transport direction on the paper after image printing, thereby drying the paper on the paper as compared with the case of blowing the drying air perpendicular to the paper. The time that the wind is hit can be lengthened. That is, when the drying air is blown perpendicularly to the paper, the drying air is directly applied only to the surface facing the air outlet of the drying means, but as in the present invention, the air is directed downstream in the paper conveying direction. If the drying air is blown, the drying air can be directly blown even on the paper moving downstream in the transport direction, and the drying time of the paper can be ensured for a long time and the paper is efficiently dried. be able to.

  Also, since the drying air blown on the paper is blown out of the housing through the exhaust port of the drying chamber and the exhaust port of the housing, the paper that is being exhausted to the outside through the exhaust port and the exhaust port Also, drying can be promoted by blowing dry air. Furthermore, by blowing dry air outside the housing, it is possible to prevent heat from being trapped inside the housing, and heat generated by the drying means is transferred to a heat-sensitive unit, for example, a back surface printing unit using an ink ribbon. This can be suppressed, which is preferable.

The invention of claim 2 is the invention according to claim 1,
A discharge roller for discharging the paper after image printing out of the casing is provided in the vicinity of the discharge port in the casing.
The discharge roller is formed with a ventilation portion for allowing the drying air blown toward the downstream side in the paper conveyance direction by the drying means to vent to the discharge port side.

  In this way, a ventilation part is formed in the discharge roller, and the drying air is exhausted to the discharge port side through the ventilation part. Therefore, the drying air is blown to the paper that is being discharged to the outside by the discharge roller. Thus, drying can be promoted and heat can be prevented from being trapped inside the housing.

The invention of claim 3 is the invention of claim 2,
The discharge roller has a roller shaft extending in the width direction of the paper, and a plurality of roller portions arranged at intervals in the axial direction of the roller shaft,
The ventilation portion is provided between the plurality of roller portions.

  As described above, since the ventilation portion for allowing the drying air to flow is provided between the plurality of roller portions spaced apart from each other in the axial direction of the roller shaft of the discharge roller, the drying air can be discharged without releasing the pressure bonding of the discharge roller. Can smoothly vent the ventilation part of the discharge roller, and the drying air can be blown on the paper that is being discharged to the outside by the discharge roller to accelerate the drying, and the inside of the housing can be heated. It is possible to suppress the accumulation.

The invention of claim 4 is the invention according to claim 1,
A heat insulating material is provided on the upstream side of the outer wall of the main body of the drying means in the paper conveying direction.

  Thereby, it can suppress that the heat radiated | emitted from a drying means is transmitted to the unit weak to the heat arrange | positioned in the upstream of a paper conveyance direction, for example, a back surface printing unit using an ink ribbon.

The invention of claim 5 is the invention of claim 1,
The casing is formed with an inlet for sucking air used for drying in the casing.
The drying means has suction means for sucking air through the suction port, and heating means for heating the air sucked by the suction means,
The suction port of the housing is opened in the vicinity of the discharge port.

  As a result, the drying air exhausted from the discharge port is again sucked into the housing from the suction port before being cooled by the air outside the housing, heated by the heating means, and sprayed again on the paper as drying air. Therefore, the heat efficiency for heating the sucked air is improved, which is advantageous in increasing the drying capacity.

  As described above, according to the inkjet printer of the present invention, the drying means blows the drying air toward the downstream side in the paper transport direction on the paper after image printing by the drying means, so that the drying air is perpendicular to the paper. Compared with the case of spraying, it is possible to lengthen the time for which the dry air is applied to the paper. That is, when the drying air is blown perpendicularly to the paper, the drying air is directly applied only to the surface facing the air outlet of the drying means, but as in the present invention, the air is directed downstream in the paper conveying direction. If dry air is blown, the dry air can be blown directly on the paper that is moving downstream in the transport direction, ensuring a long drying time for the paper and efficient drying. It is advantageous in obtaining.

  Also, since the drying air blown on the paper is blown out of the housing through the exhaust port of the drying chamber and the exhaust port of the housing, the paper that is being exhausted to the outside through the exhaust port and the exhaust port Again, dry air can be blown. Furthermore, by blowing dry air outside the housing, it is possible to prevent heat from being trapped inside the housing, and heat generated by the drying means is transferred to a heat-sensitive unit, for example, a back surface printing unit using an ink ribbon. This can be suppressed, which is preferable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows an appearance of an ink jet printer A according to an embodiment of the present invention, and FIGS. 2 to 7 show an internal configuration of the ink jet printer A. FIG. The inkjet printer A is used in a photographic print system. For example, print paper based on image data transmitted via a communication cable from a reception block that acquires image data and performs necessary correction processing and the like. Automatic printing that prints on P1 and P2, and pulls out one end of a long print paper P2 wound in a roll shape and prints on the print surface of the print paper P2 (hereinafter referred to as roll paper P2). It is configured to be able to execute printing and manual-feed printing that performs printing on a print surface (corresponding to a print surface) of a sheet-like print paper P1 (hereinafter referred to as sheet paper P1) that has been cut into a predetermined size in advance. Yes.

  In the following description, when it is not necessary to distinguish between the roll paper P2 and the sheet paper P1, the roll paper P2 and the sheet paper P1 are referred to as print papers P1 and P2. The printed surface means a surface on which printing is performed, and the printed surface of the sheet paper P1 is determined when the sheet paper P1 is set on the manual feed tray 81 (see FIG. 7). Specifically, when the sheet paper P1 is set on the manual feed tray 81, the surface facing upward is the print surface. In addition, the print surface of the roll paper P2 is a surface that faces radially outward when the roll paper P2 is wound in a roll shape.

-Overall configuration-
As shown in FIG. 7, the ink jet printer A includes a printer main body 90 and a manual feed tray 81 for manually setting and feeding the sheet paper P1 into the printer main body 90. The printer main body 90 is provided in the housing 6 and in the lower part of the housing 6, and the roll paper housing portion 1 (housing chamber) in which the roll paper P <b> 2 wound in a roll shape with the printing surface facing outside is housed. And the print surface of the sheet paper P1 supplied from the manual feed tray 81 or the roll paper P2 drawn out from the roll paper storage portion 1 provided on the upper portion of the housing 6 (upper side of the roll paper storage portion 1). The print unit 2 (see FIGS. 2 and 7) that performs printing on the print surface based on the image data, and the roll paper storage unit 1 at the bottom of the housing 6 An ink storage part 3 for storing ink to be supplied to the print unit 2 and a door member 95 that is attached to the housing 6 so as to be openable and closable, A roller unit 200 that conveys and feeds the sheet paper P1 set on the manual feed tray 81 toward the printing unit 2 when the member 95 is in the closed state.

  A roller cutter 41 for cutting unnecessary portions of the printed paper P1 and P2 after printing, and the print paper P1 and P2 on the downstream side in the transport direction of the printing unit 2 above the housing 6 The back side printing unit 4 for printing the reference number on the back side, the drying unit U6 for drying the print papers P1, P2 printed by the printing unit 2, and the printing papers P1, P2 printed by the printing unit 2 further downstream A discharge roller 46 is disposed to be conveyed to the side and discharged. A discharge tray 5 is provided on the downstream side of the discharge roller 46 in the paper conveyance direction so as to protrude outward from the discharge port 47 of the housing 6 and for receiving the print papers P1 and P2 discharged by the discharge roller 46. It is arranged.

  In this embodiment, the side of the discharge tray 5 (the discharge side shown in FIG. 3) in the case 6 is referred to as the front side of the case, and the side opposite to the discharge tray 5 (the supply side shown in FIG. 3) is the rear side of the case. The left side when viewed from the front side of the casing is called the left side of the casing, and the right side is called the right side of the casing. Accordingly, the left-right direction in FIG. 7 is the front-rear direction of the casing, and the direction perpendicular to the paper surface of FIG. The lateral direction of the housing coincides with the width direction of the sheet paper P1 set and transported on the manual feed tray 81 and the width direction of the roll paper P2 stored and transported in the roll paper storage unit 1.

  The print unit 2 includes a print head H (see FIGS. 2 to 4 and 7) that forms an image by ejecting ink onto the print papers P1 and P2. The print head H is configured to be movable along a rail 30 that extends in a main scanning direction X (see FIG. 3) that coincides with the width direction of the print papers P1 and P2 (case left-right direction). Specifically, the rotational force of the drive motor 32 is transmitted to the drive belt 31 via a pulley, and the print head H moves in the main scanning direction X according to the rotation amount of the drive belt 31.

  The print head H has two head units 38 (lined up in a sub-operation direction Y (see FIG. 3) that is perpendicular to the main scanning direction X and coincides with the movement direction of the print papers P1 and P2 (front-rear direction of the casing). 7), and by ejecting ink from ink ejection nozzles (not shown) provided in these two head units 38, predetermined images, characters, etc. are applied to the print paper P1, P2. Can be printed.

  Each of the ink reservoirs 3 includes a box-shaped case 61 (see FIG. 4) disposed on both the left and right sides of the ink jet printer A. In the case 61, inks having different hues are sealed. Seven ink cartridges 62 are detachably accommodated (in FIG. 4, three cartridges are accommodated on the left side and four cartridges are accommodated on the right side). Therefore, by removing these ink cartridges 62 from the case 61, the used or used ones can be replaced with new ones. Each of these ink cartridges 62 includes yellow (Y), magenta (M), cyan (C), black (K), red (R), violet (V), and clear (CL: transparent) inks. Is enclosed.

  Further, on the left side when viewed from the discharge side of the ink jet printer A, a height position between the ink storage unit 3 and the print unit 2 is used for temporarily storing ink supplied from the ink cartridge 62. A sub tank 52 (see FIGS. 4 and 5) is provided. These sub tanks 52 are connected to the print head H of the print unit 2, and ink in the sub tank 52 is supplied to the print head H by negative pressure when ink is ejected from the nozzles of the print head H. It is like that.

-Paper transport mechanism-
As shown in FIG. 7, the ink jet printer A is provided with a paper transport mechanism that pulls in the sheet paper P1 from the manual feed tray 81 and transports it along a predetermined transport path. This paper transport mechanism includes a manual feed unit U5, a print unit U2, a cutter unit U3, a drying unit U6, and a discharge unit U4 in order from the manual feed tray to form the transport path. Image data is printed on the print surface of the print paper P1, P2 located on the transport path of the arranged print unit U2. In this embodiment, in addition to supplying the sheet paper P1 from the manual feed tray 81 to the print unit U2, the roll paper P2 can be pulled out from the roll paper storage unit 1 and conveyed to the print unit 2. A supply unit U1 configured as described above is also provided.

  When printing on the sheet paper P1, the paper transport mechanism transports and supplies the sheet paper P1 set on the manual feed tray 81 to the print unit U2 by the manual feed unit U5, and then supplies the supplied sheet paper P1 to the print unit. The image data is printed by the print head H while being conveyed by U2, and then the printed sheet paper P1 is conveyed to the cutter unit U3 and cut into a predetermined print size by the cutter unit U3, and then the drying unit U6. The sheet paper P1 is dried and sent out to the discharge tray 5 by the discharge unit U4. In the following description, the upstream side and the downstream side in the transport direction when the sheet paper P1 is transported during printing are simply referred to as the upstream side and the downstream side, respectively.

  The manual feed unit U5 includes a roller unit 200 for guiding the sheet paper P1 to the printing unit 2. The roller unit 200 includes a driving roller 202 and a driven roller 201. Then, the manual feed unit U5 guides the sheet paper P1 from the manual feed tray 81 into the printer main body 90 by rotating the drive roller 202.

  The supply unit U1 positions the roll paper P2 in the roll paper accommodating portion 1 in a roll shape and accommodates the roll paper P2 drawn out from the core roller 21 in the width direction. A width regulating roller 22 for carrying out, a closing roller 23 to be described later, a conveyance driving roller 24 that is rotationally driven so as to convey the roll paper P2 by an electric motor (not shown), and disposed opposite to the conveyance driving roller 24; Two pressure-bonding rollers 25 that are pressed against the conveyance drive roller 24 so as to sandwich the roll paper P <b> 2 between the conveyance drive roller 24 are provided.

  The supply unit U <b> 1 is configured to pull the roll paper P <b> 2 from the roll paper storage unit 1 and convey it to the printing unit 2 side by the rotation drive of the conveyance drive roller 24. In this embodiment, the width restricting roller 22 is provided, but a width restricting guide may be provided instead.

  The closing roller 23 is provided in order to ensure the airtightness of the roll paper container 1 and prevent the inside of the roll paper container 1 from being in a low humidity state. That is, a paper outlet opening for leading the roll paper P <b> 2 to the outside of the roll paper container 1 inside the housing 6 (that is, the print unit 2 side) is formed in a part of the wall that forms the roll paper container 1. 9 need to be formed. If the paper lead-out opening 9 is left open, the airtightness of the roll paper storage unit 1 cannot be ensured. Accordingly, the paper outlet opening 9 is provided with a closing roller 23 that closes the paper outlet opening 9 so that the roll paper P2 can pass therethrough.

  The closing roller 23 is formed of an elastically deformable material such as a foam material such as a sponge material or a rubber material at least at the outer peripheral portion, and the roll roller P2 passes through the paper lead-out opening 9. Thus, they are rotated in contact with each other while being elastically deformed radially inward. At this time, the roll paper P2 is pressed against the guide member 10 provided on the side opposite to the closing roller 23 (this pressing force is considerably small). In this way, the roll paper P2 can pass through the paper outlet opening 9 while receiving almost no resistance from the closing roller 23 while ensuring the airtightness of the roll paper container 1.

  The closing roller 23 may be configured to operate as a driving roller that actively feeds or rewinds the roll paper P2 in the transport direction. If the rotation driving force of the closing roller 23 can be transmitted to the closing roller 23 by an electromagnetic clutch (not shown) or the like, it is not necessary to provide a separate electric motor, and space saving of the apparatus can be achieved. It is advantageous for cost reduction.

  On the other hand, when the roll paper P2 is not present in the paper outlet opening 9, the closing roller 23 is in contact with the guide member 10, and at this time, the air tightness of the roll paper storage unit 1 is ensured. In this way, the roll paper container 1 in which airtightness is ensured is provided with a container 13 that contains water and is opened at the top, and the water in the container 13 is vaporized into water vapor to accommodate the roll paper. The inside of the part 1 is efficiently humidified.

  As a result, even when the ink jet printer A itself is placed under low humidity for a long time, the inside of the roll paper container 1 can be used in a moderate humidity (relative humidity range of 30 to 75%. Preferably 40 to 40%. 60%), it is possible to prevent the occurrence of curling such that the central portion in the width direction of the roll paper P2 protrudes toward the print surface with respect to both end portions in the width direction.

  The transport drive roller 24 is rotated in the forward direction to pull the roll paper P2 from the roll paper storage unit 1 and transport it to the print unit 2 side by an electric motor (not shown), and the roll paper P2 into the roll paper storage unit 1. The rotation in the reverse direction is possible.

  Thereby, after the printed part of the roll paper P2 is cut into a predetermined size by the cutter unit U3 on the downstream side of the print unit 2, the long roll paper P2 after the cutting is returned to the upstream side, and the roll paper P2 Printing is performed from the top of the paper, or the long roll paper P2 after cutting is returned to the roll paper storage unit 1, and the sheet-like print paper is supplied to the printing unit 2 by the manual feed unit U5 for printing. To be able to go. Further, when the long roll paper P2 is replaced with a new one, the long roll paper P2 drawn out of the roll paper storage unit 1 can be returned into the roll paper storage unit 1.

  The print unit U2 includes a paper holding part D (see FIGS. 3 and 7) for sucking and holding the print papers P1 and P2 at positions where printing can be performed by the print head H, and a downstream side of the paper holding part D. And a press-fitting type print transport roller 33 disposed in the head. The transport driving roller 24 and the pressure roller 25 of the supply unit U1 are also used as the print unit U2, and serve to transport the print papers P1 and P2 in the print unit U2.

  The paper holding part D sucks the platen 34 having a suction hole 34a (see FIG. 3) opened on the surface (upper surface) and the print papers P1 and P2 supplied onto the platen 34 by the supply unit U1. A fan 35 (see FIG. 7) is provided as a suction unit that sucks and holds the surface of the platen 34 by sucking through the hole 34a. The platen 34 is formed of a plate-like member, and a case body 36 that forms a space with the platen 34 is disposed on the back surface (lower surface) side of the platen 34, and the fan is disposed below the case body 36. 35 is disposed. The suction hole 34 a penetrates in the thickness direction of the platen 34 and communicates with a space in the case body 36, and this space communicates with the suction opening of the fan 35 through an opening provided in the lower portion of the case body 36. When the fan 35 is actuated, a negative pressure is generated on the surface side of the platen 34 through the suction hole 34a, whereby the print papers P1 and P2 are sucked and held on the surface of the platen 34.

  Further, the platen 34 has a flushing portion 37 (see FIG. 3) for receiving a small amount of ink ejected from the ink ejection nozzles of the head unit 38 in the print head H in order to prevent thickening of ink during printing, and non-printing. And a cap portion (not shown) configured to cover the ink discharge nozzles of the head unit 38 in the print head H in order to prevent thickening of the ink. ing.

  The flushing portion 37 is provided with an opening 37a (see FIG. 3) formed in the platen 34 and a lower side of the flushing portion 37 in the platen 34 to form a space communicating with the opening 37a. The case body communicates with a waste liquid tank 7 (see FIGS. 2 and 7) provided at the lower front side of the casing of the inkjet printer A. In addition, a sponge-like ink absorbing material 37b capable of absorbing ink is disposed in the opening 37a, and the ink soaked into the ink absorbing material 37b is also located below the flushing portion 37. It is designed to accumulate in the space inside the body. As a result, the ink ejected toward the opening 37a of the flushing portion 37 is guided to the waste liquid tank 7 after accumulating in the space inside the case body.

  The cap portion is not particularly shown, but when the cap portion covers the lower surface of the print head H, a space is formed in which a negative pressure is formed, and a small amount is formed in the space from the ink ejection nozzle. It is configured to suck out the ink. Accordingly, it is possible to prevent the ink from becoming difficult to be ejected due to the viscosity increase of the ink by the ink ejection nozzle.

  As described above, the print head H has a head unit 38 provided with a large number of ink discharge nozzles arranged in two stages in the sub-scanning direction Y on the bottom surface (the surface facing the platen 34). However, the head unit 38 does not have to be two stages, and may be one stage or three stages or more.

  Both the head units 38 have the same configuration, and are each composed of seven nozzle arrays arranged in the main scanning direction X for ejecting the inks of the respective colors. In each nozzle array, the ink discharge nozzles are arranged in a row in the sub-scanning direction Y. Accordingly, each head unit 38 is configured to be able to form a color image by itself. The print papers P1 and P2 are intermittently (stepwise) conveyed in the sub-scanning direction Y by a constant unit conveyance amount by the conveyance drive roller 24, and each stop of the print papers P1 and P2 during the intermittent conveyance is performed. Sometimes, the print head H is scanned once in the main scanning direction X (one-way operation or one-time operation), and ink is discharged from the ink discharge nozzles of each color of each head unit 38 at each position in the main scanning direction X during this scanning. Are simultaneously ejected onto the print surface of the print paper P1, P2. That is, after one scan of the print head H, the print papers P1 and P2 are transported by the unit transport amount, and then the print head H is scanned once again, and this operation is repeated to print a desired image. become. Here, as a configuration for ink discharge of the print head H in the present embodiment, ink is discharged from an ink discharge nozzle communicating with the pressure chamber by changing the volume of the pressure chamber filled with ink by a piezo element. The general piezo type is used.

  The cutter unit U3 includes a rotary blade 41, and the print paper P1 and P2 are moved in the width direction at predetermined positions in the length direction of the print paper P1 and P2 while rotating the rotary blade 41. It is configured to cut into a predetermined size (length). Below the rotary blade 41, a cutter waste collection box 65 for collecting chips of the print paper P1, P2 by cutting is disposed. The cutter waste collection box 65 can be taken out of the housing 6 by the operator holding the handle 66 and sliding it toward the front of the housing. The waste can be discarded. Note that the front side surface of the casing of the cutter waste collection box 65 is formed of a transparent plastic material so that the state of accommodation of the chips can be visually confirmed.

  In addition, the cutter unit U3 is configured to convey the print papers P1 and P2 to the discharge unit U4 by means of a pressure-type conveyance roller 43. A back side printing unit 4 is disposed between the cutter unit U3 and the discharge unit U4, and the back side printing unit 4 is arranged on the back side (lower side) of the print paper P1, P2 passing through this portion. Numbers etc. are printed.

  Hereinafter, the discharge roller 46 and the drying unit U6, which are features of the present invention, will be described with reference to FIGS. The discharge unit U4 has two sets of pressure-bonding type discharge rollers 46 and 46 for conveying the print papers P1 and P2 and discharging them to the discharge tray 5.

  The discharge roller 46 includes a roller shaft 46a that extends in the width direction of the print papers P1 and P2, and a plurality of roller portions 46b that are spaced apart from each other in the axial direction of the roller shaft 46a. Between the adjacent roller portions 46b and 46b, a ventilation portion 46c is provided for allowing the drying air blown toward the downstream side in the paper transport direction by the drying unit U6 to vent the discharge port 47 side.

  Further, a drying unit U6 is provided between the two sets of pressure-bonding type discharge rollers 46, 46 of the discharge unit U4 to blow dry air on the print papers P1, P2 to dry the print papers P1, P2. . The drying unit U6 sucks air into the housing 6 from the suction port 48 formed near the upper portion of the discharge port 47 of the housing 6, heats the sucked air, and blows it as dry air. A dust collection filter 49 is attached to the suction port 48 to prevent dust in the air from being sucked into the drying unit U6.

  As shown in FIG. 8, the drying unit U6 includes a drying chamber 71 provided on the transport path of the print papers P1 and P2, and a drying device 72 (drying means) that blows drying air to the drying chamber 71. ing. The drying chamber 71 is partitioned by an upper partition wall 71a and a lower partition wall 71b that are opposed to each other with the print papers P1 and P2 interposed therebetween. The drying chamber 71 retains the drying air blown from the drying device 72 to the print papers P1 and P2. It constitutes a space.

  The drying device 72 includes a plurality of suction fans 73 arranged at intervals in the left-right direction of the housing 6 in order to take air into the drying device 72 from outside through the suction port 48 of the housing 6, and the suction fans 73. A heater 74 that heats the air taken in at the bottom, and is provided at the lower end of the drying device 72 and opens toward the downstream side in the paper conveyance direction, and blows the drying air heated by the heater 74 toward the downstream side in the conveyance direction. An exhaust nozzle portion 75 and a safety thermo 76 that detects the temperature in the drying device 72 and urgently stops the heater 74 are provided. Further, a heat insulating material 77 is provided on the upstream side in the paper transport direction of the outer wall of the main body of the drying device 72 including the exhaust nozzle portion 75. By providing such a heat insulating material 77, the heat radiated from the drying device 72 is transmitted to a unit that is weak against heat disposed on the upstream side in the paper conveyance direction, for example, the back surface printing unit 4 using an ink ribbon. Heating can be suppressed.

  The drying unit U6 blows dry air toward the downstream side in the paper conveyance direction on the print papers P1 and P2 after image printing, and the blown dry air is supplied to the ventilation portion 46c of the discharge roller 46 and the casing. 6 (in this embodiment, the discharge port 47 also serves as the exhaust port of the drying chamber 71) and is blown out of the housing 6.

  By providing such a drying unit U6, even when the ink ejected from the print head H to the print papers P1 and P2 is not yet dried, the drying of the ink can be promoted by blowing the drying air. it can. And since it is set as the structure which blows dry air toward the downstream of a paper conveyance direction, it can lengthen the time for which dry air is hitting print paper P1, P2. That is, when the drying air is blown perpendicularly to the print papers P1 and P2, the drying air directly hits only the surface of the drying device 72 that faces the air outlet of the exhaust nozzle portion 75, but as in the present invention. If the drying air is blown toward the downstream side in the paper conveyance direction, the drying air can be directly blown to the print papers P1 and P2 that are moving toward the downstream side in the conveyance direction. , P2 can be secured for a long time and can be dried efficiently. This is advantageous in preventing problems such as color unevenness occurring in the printed image because the ink does not dry uniformly when the print papers P1 and P2 are stacked on the discharge tray 5.

  In addition, the drying air blown on the print papers P1 and P2 is blown out of the housing 6 through the ventilation portion 46c of the discharge roller 46 and the discharge port 47 of the housing 6, so Drying can also be sprayed on the print paper P1 and P2 in the middle of being discharged to promote drying. That is, it is possible to dry smoothly without releasing the pressure bonding of the discharge roller 46. Further, by blowing out the drying air from the outlet 47 to the outside of the housing 6, it is possible to suppress heat from being trapped inside the housing 6, and that the heat generated in the drying unit U 6 is transferred to the back surface printing unit 4 and the like. It can be suppressed and is preferable.

  Further, since the suction port 48 for sucking air into the drying device 72 is formed in the vicinity of the upper portion of the discharge port 47 through which the dry air is blown out, the dry air exhausted from the discharge port 47 is outside the housing 6. In order to heat the sucked air, the air is sucked again into the housing 6 from the suction port 48 before being cooled by the air, and heated by the heater 74 and sprayed again on the print paper P1 and P2 as dry air. This is advantageous for improving the drying efficiency by improving the thermal efficiency.

-Ink supply system-
As shown in FIG. 5, the ink supply system of the ink jet printer A is configured such that the ink in the ink cartridge 62 of the ink reservoir 3 located on both the left and right sides of the ink jet printer A is supplied to the sub tank via the electromagnetic valve 50 and the supply pipe 51. The ink in the sub tank 52 is sent out to the print head H through the flexible pipe 53.

  From the ink cartridge 62 to the sub tank 52, ink is sent out by pressurized air supplied into the ink cartridge 62 by a pressure pump (not shown), while from the sub tank 52 to the print head H, the print head The ink flows due to the negative pressure generated in the pressure chamber when the ink is ejected from the H nozzle.

  The sub-tanks 52 are formed in a bag shape using a flexible material such as a resin sheet, and seven sub tanks 52 are provided corresponding to seven types of inks having different hues. The seven sub tanks 52 are attached to the print head H at predetermined height positions so that ink is supplied to the print head H at an appropriate pressure.

  As described above, the ink in the ink cartridge 62 is temporarily stored in the sub tank 52 and then supplied from the sub tank 52 to the print head H. For this reason, the ink cartridge 62 can be replaced without interrupting printing. Moreover, since the sub tank 52 also serves as a pressure damper, it is possible to prevent the pressure fluctuation generated in the ink cartridge 62 from being directly transmitted to the print head H, and an excessive pressure is applied to the print head H. Can prevent ink leakage and the like from occurring.

  As described above, according to the ink jet printer A according to the embodiment of the present invention, the drying unit U6 blows the drying air toward the downstream side in the paper transport direction with respect to the print paper P1 and P2 after image printing. Thus, as compared with the case where the drying air is blown perpendicularly to the print papers P1 and P2, the time during which the drying air is applied to the print papers P1 and P2 can be lengthened and can be efficiently dried.

  In addition, the drying air blown on the print papers P1 and P2 is blown out of the housing 6 through the ventilation portion 46c of the discharge roller 46 and the discharge port 47 of the housing 6, so Drying can also be sprayed on the print paper P1 and P2 in the middle of being discharged to promote drying. Further, the drying air is blown out of the housing 6 so that heat can be prevented from being trapped inside the housing 6, and generated in the drying unit U 6 in a heat-sensitive unit, for example, the back surface printing unit 4 using an ink ribbon. It is preferable because heat can be prevented from being transferred.

  As described above, the present invention provides a highly practical effect that can provide an ink jet printer capable of ensuring a long drying time of paper without reducing the paper conveyance speed. It is extremely useful and has high industrial applicability.

1 is a perspective view showing an appearance of an ink jet printer as an image forming apparatus according to an embodiment of the present invention. It is a perspective view which shows the structure inside the housing | casing of an inkjet printer. It is a top view which shows the structure inside the housing | casing of an inkjet printer. It is a front view which shows the structure inside the housing | casing of an inkjet printer. It is a left view which shows the structure inside the housing | casing of an inkjet printer. It is a rear view which shows the structure inside the housing | casing of an inkjet printer. It is the schematic seen from the housing | casing left side which shows the conveyance path | route of a print paper. It is sectional drawing seen from the housing | casing left side which shows the structure of a drying unit. It is a top view which shows the structure of a discharge roller.

Explanation of symbols

A Inkjet printer P1 Sheet paper P2 Roll paper H Print head 6 Housing 46 Discharge roller 46a Roller shaft 46b Roller portion 46c Ventilation portion 47 Discharge port (exhaust port)
48 Suction port 71 Drying chamber 72 Drying device (drying means)
73 Suction fan (suction means)
74 Heater (heating means)
77 Insulation

Claims (5)

An inkjet printer that prints an image on a paper by discharging ink from the print head to the paper,
A housing containing the print head and having a discharge port for discharging the paper after image printing to the outside;
A drying chamber provided on a transport path downstream in the paper transport direction from the print head in the housing, and having an exhaust port communicating with the discharge port;
Drying means for blowing a drying air for drying the paper into the drying chamber;
The drying means blows dry air toward the downstream side in the paper transport direction on the paper after image printing, and the blown dry air is passed through the exhaust port of the drying chamber and the exhaust port of the housing. An ink jet printer configured to blow out of the casing. In claim 1,
A discharge roller for discharging the paper after image printing out of the casing is provided in the vicinity of the discharge port in the casing.
The ink jet printer according to claim 1, wherein the discharge roller is formed with a ventilation portion for allowing the drying air blown toward the downstream side in the paper conveyance direction by the drying unit to vent to the discharge port side. In claim 2,
The discharge roller has a roller shaft extending in the width direction of the paper, and a plurality of roller portions arranged at intervals in the axial direction of the roller shaft,
The ink jet printer, wherein the ventilation portion is provided between the plurality of roller portions. In claim 1,
An ink jet printer, wherein a heat insulating material is provided upstream of the outer wall of the main body of the drying unit in the paper conveying direction. In claim 1,
The casing is formed with an inlet for sucking air used for drying in the casing.
The drying means has suction means for sucking air through the suction port, and heating means for heating the air sucked by the suction means,
An ink jet printer according to claim 1, wherein the suction port of the housing opens in the vicinity of the discharge port.

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