JP5023882B2 - Inkjet printer - Google Patents

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.

  In addition, instead of using an infrared heater, it may be possible to dry the paper by providing a drying means for blowing the air heated by the heater to the paper. However, since the air used for drying is taken in from the outside of the apparatus, It takes time to raise the air to a temperature for obtaining the required drying capacity, and during that time, the paper cannot be dried, and the overall processing capacity of the printer may be 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 shorten the temperature rise time of the drying air without reducing the paper processing capacity. It is in.

  In order to achieve the above-described object, in the present invention, the drying means blows drying paper onto the paper after image printing, and the drying air having a high temperature used for drying is again taken into 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 means disposed in the casing and drying the paper by blowing a drying air on the paper after image printing;
The casing is formed with an inlet for sucking air used for drying into the casing and an exhaust outlet for exhausting the drying air blown from the drying means to the outside of the casing,
Between the suction port and the exhaust port, a circulation flow path that guides the dry air exhausted from the exhaust port to the suction port is provided,
The drying means has a heating means for heating the air sucked through the suction port, and a part of the drying air heated by the heating means is blown out of the casing through the discharge port of the casing. On the other hand, the remaining dry air is configured to be blown out to the circulation flow path through the exhaust port.

  In this way, a part of the drying air blown out from the drying means is blown out of the housing through the housing discharge port, while the remaining drying air is blown out to the circulation channel through the exhaust port, thereby heating the heater. It is possible to circulate by guiding the dry air heated at high temperature from the exhaust port to the suction port. In other words, the drying air having a higher temperature than the outside air is circulated and taken into the drying means, so that the temperature can be raised to a required temperature in a shorter time than when air at room temperature is taken in and heated up. Therefore, the drying air can be efficiently heated.

The invention of claim 2 is the invention according to claim 1,
The circulation channel is configured by an outer cover that covers the suction port and the exhaust port and has a circulation space inside,
The outer cover is formed with an outside air inlet for sucking air outside the outer cover into the circulation space.
The air sucked into the external cover through the outside air inlet and the dry air exhausted through the exhaust port are mixed in the circulation space of the outer cover, and the mixed air is mixed with the inlet. The air is sucked into the housing through the.

  In this way, the external cover constitutes a circulation flow path, and the air sucked through the external suction port and the dry air exhausted through the exhaust port are mixed in the circulation space, and the mixed air is sucked. Since it is taken into the drying means from the mouth, it is possible to suppress variation in the temperature distribution inside the main body of the drying means and to generate a drying air having a desired drying capacity.

  Specifically, when only the dry air exhausted from the exhaust port is led to the intake port and taken into the drying means without providing the outside air intake port in the external cover, the temperature of the dry air is high, so that the necessary drying capacity is obtained. However, instead of a short temperature rise time, the temperature distribution is biased in such a way that the temperature rises only at specific locations in the body of the drying means. There is a possibility that the dried state becomes uneven and uneven drying occurs. However, as in the present invention, if the outside cover is provided with the outside air inlet and the drying air and the outside air are mixed in the circulation space, the air diffusibility is increased inside the main body of the drying means, and this mixing is performed. Even if the air is taken into the drying means, the temperature distribution is less likely to vary within the main body of the drying means, and a drying air having a desired drying ability can be generated.

The invention of claim 3 is the invention of claim 2,
The outer cover is provided at a position above the outlet of the housing,
An outside air inlet of the outer cover is formed in the vicinity of the outlet, and dry air blown out through the outlet of the housing is sucked into the circulation space through the outside air inlet. Is.

  Thus, since the outside air intake port of the outer cover is formed in the vicinity of the discharge port of the housing, the dry air blown out of the housing from the discharge port of the housing can be taken into the circulation space of the outer cover. In other words, dry air is blown on the paper that is being discharged from the discharge port of the housing to accelerate drying, and the dry air used for drying is sucked into the circulation space from the outside air intake port of the outer cover. The drying air having a higher temperature than the outside air can be actively circulated to generate the drying air having a desired drying capacity more efficiently.

  In addition, by making the lower surface of the outer cover with the outside air inlet open facing the paper, a residence space for temporarily retaining the drying air can be provided between the paper surface and the lower surface of the outer cover. This is advantageous in accelerating the drying of the paper by avoiding the problem that the paper cannot be sufficiently blown against the paper due to diffusion.

The invention of claim 4 is the invention of claim 2 or 3,
The outside air inlet of the outer cover is formed so as to open to the downstream side of the outer cover in the paper transport direction.

  Thus, by forming the outside air intake port of the outer cover so as to open downstream in the paper transport direction, while ensuring a long time for the drying air to stay between the paper surface and the lower surface of the outer cover, Air used for drying can be taken into the circulation space from the external suction port, which is advantageous in suppressing variation in temperature distribution inside the main body of the drying means.

Invention of Claim 5 in any one of Claims 1 thru | or 4,
A pressure-type discharge roller provided near the discharge port of the housing and having an upper roller and a lower roller facing the upper roller;
The discharge roller is a roll paper in which the paper after the image printing is wound in a roll shape, and a common tangent line on the roller surface of the upper roller and the lower roller has a predetermined angle with respect to the paper transport path. As described above, the relative positions of the upper roller and the lower roller are changed.

  Thus, when the paper after image printing is a roll paper, the upper roller and the lower roller are relatively positioned so that the common tangent line on the roller surface of the upper roller and the lower roller has a predetermined angle with respect to the paper transport path. Since the position is changed, a sufficient retention space can be provided between the lower surface of the outer cover and the paper surface for temporarily retaining the drying air, which is advantageous in promoting the drying of the paper. Become.

  Specifically, when the paper is curled upward due to being wound in a roll shape, the paper discharged from the discharge port is not discharged as it is, but the front end is at the bottom. It is discharged in the state of hanging down. For this reason, the gap between the lower surface of the outer cover and the paper surface becomes large, and the drying air exhausted from the discharge port diffuses outside the residence space without staying in the residence space, and the paper is sufficiently dried. There is a risk that it may not be possible. However, if the relative position of the upper roller and the lower roller is changed so that the paper discharged by the discharge roller is discharged obliquely upward with respect to the paper transport path as in the present invention, the paper is curled. Even when the tip portion hangs downward, a sufficient retention space can be provided between the lower surface of the outer cover and the paper surface for temporarily retaining the drying air.

  As described above, according to the ink jet printer of the present invention, a part of the dry air blown from the drying means is blown out of the housing through the discharge port of the housing, while the remaining dry air is blown through the exhaust port. By blowing out to the circulation channel, it is possible to guide and circulate the dry air heated by the heater and having a high temperature from the exhaust port to the suction port. For this reason, it is possible to raise the temperature to a required temperature in a shorter time than when air at room temperature is taken in and heated up by circulating high-temperature drying air into the drying means. Therefore, the drying air can be efficiently heated.

  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 Upstream and downstream discharge rollers 45 and 46 are disposed for transporting and discharging to the side. The downstream discharge roller 46 is provided on the downstream side 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 downstream discharge roller 46. A discharge tray 5 is provided.

  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 increase in the viscosity 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.

  The discharge unit U4 includes a pressure-bonding upstream discharge roller 45 and a downstream discharge roller 46 for conveying the print papers P1 and P2 and discharging them to the discharge tray 5.

  The upstream and downstream discharge rollers 45 and 46 are pressure-type rollers, and upper rollers 45a and 46a that press the print surface of the print paper P1 and P2, and the print paper P1 and the upper rollers 45a and 46a. And lower rollers 45b and 46b for pressing the back surface of P2.

  As shown in FIG. 8, the upstream and downstream discharge rollers 45 and 46 are arranged with a roller shaft 55 extending in the width direction of the print paper P <b> 1 and P <b> 2 and an axial direction of the roller shaft 55 spaced apart from each other. The plurality of roller portions 56, 56,. As will be described in detail later, the downstream discharge roller 46 is configured to change the transport direction of the print papers P1 and P2 by changing the relative position between the upper roller 46a and the lower roller 46b.

  Hereinafter, the drying unit U6, which is a characteristic part of the present invention, will be described with reference to FIGS. A drying unit U6 is provided between the upstream and downstream discharge rollers 45 and 46 of the two sets of the pressure bonding type of the discharge unit U4 to blow the print paper P1 and P2 and dry the print paper P1 and P2. It has been. The drying unit U6 sucks air into the housing 6 from the suction port 48 formed in the vicinity of the discharge port 47 of the housing 6, heats the sucked air and blows it as dry air, and print paper P1. , P2 is exhausted from the exhaust port 49 to the outside of the housing 6.

  The drying unit U6 includes a drying chamber 71 provided on the transport path of the print papers P1 and P2, a drying device 72 (drying means) for blowing drying air to the drying chamber 71, and drying exhausted from the exhaust port 49. An external cover 70 (circulation flow path) for guiding the wind to the suction port 48 is provided. 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 75, a safety thermo 76 that detects the temperature in the drying device 72 and stops the heater 74 in an emergency, and a thermo sensor 78 that is provided near the downstream side of the exhaust nozzle 75 and measures the temperature of the drying air It has. 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 external cover 70 is provided at a position above the discharge port 47 of the housing 6, covers the suction port 48 and the exhaust port 49 of the housing 6, and allows the dry air exhausted from the exhaust port 49 to flow inside the external cover 70. This is for circulating the circulation space 80 and leading it to the suction port 48. In addition, on the lower surface of the outer cover 70, that is, the surface facing the print paper P 1 and P 2 discharged from the discharge port 47, an outside air inlet 79 for sucking air outside the outer cover 70 into the circulation space 80 is provided. Is formed.

  The drying unit U6 blows dry air toward the downstream side in the paper transport direction on the print papers P1 and P2 after image printing, and a part of the blown dry air is discharged to the outlet 47 of the housing 6. The remaining dry air is blown out to the circulation space 80 of the outer cover 70 through the exhaust port 49. Further, a part of the dry air blown out of the housing 6 through the discharge port 47 of the housing 6 and the air outside the external cover 70 enter the distribution space 80 through the external air suction port 79 of the external cover 70. Inhaled.

  Then, the dry air exhausted from the exhaust port 49, the air sucked from the outside air suction port 79, and the dry air blown out from the discharge port 47 and sucked through the outside air suction port 79 are inside the circulation space 80. The mixed air is taken in by the suction fan 73 of the drying device 72 through the suction port 48, heated by the heater 74, and blown to the print papers P1 and P2 as dry air. .

  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. If the drying air is blown toward the downstream side, the drying air can be directly blown to the print papers P1 and P2 that are moving downstream in the transport direction, and the drying time of the print papers P1 and P2 can be reduced. It 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.

  Further, since the dry air blown on the print papers P1 and P2 is blown out of the housing 6 through the discharge port 47 of the housing 6, the prints being discharged to the outside through the discharge port 47 Drying can also be sprayed on the papers P1 and P2 to promote drying.

  Further, since the external cover 70 is provided above the discharge port 47 for blowing dry air and the outside air intake port 79 is formed on the lower surface of the external cover 70, the dry air exhausted from the discharge port 47 is 6 The air can be taken into the circulation space 80 before being cooled by the external air, which is advantageous in improving the thermal efficiency for heating the air used for drying and increasing the drying capacity.

  Here, a staying space in which the drying air temporarily stays is provided between the lower surface of the outer cover 70 and the print papers P1 and P2. If the gap H between the staying spaces is narrow, the drying wind It is surely sprayed onto the print surface of the print papers P1 and P2 without diffusing out of the casing 6, and further drying of the print papers P1 and P2 is promoted.

  However, as shown in FIG. 12, when the roll paper P <b> 2 is discharged from the discharge port 47, the roll paper P <b> 2 curls upward in a convex shape, and thus the roll paper P <b> 2 discharged from the discharge port 47. It is discharged in a state where the tip of the tube hangs downward. For this reason, the gap H of the staying space between the lower surface of the outer cover 70 and the roll paper P2 becomes large, and the drying air exhausted from the discharge port 47 does not stay in the staying space and stays outside the housing 6. It may diffuse and the roll paper P2 may not be sufficiently dried.

  Therefore, in the present invention, the drying air is temporarily retained between the lower surface of the outer cover 70 and the roll paper P2 by changing the relative positions of the upper roller 46a and the lower roller 46b forming the downstream discharge roller 46. Therefore, a sufficient residence space can be provided. Specifically, as shown in FIG. 13, when the roll paper P2 after image printing is conveyed to the downstream discharge roller 46, the upper roller 46a is moved upstream along the outer peripheral surface of the lower roller 46b in the paper conveying direction. The common tangent line of the upper roller 46a and the lower roller 46b is set so that the leading end of the roll paper P2 is obliquely upward with respect to the paper transport path and has a predetermined angle θ.

  In this way, even when the roll paper P2 is curled and the leading end hangs downward, the drying air is temporarily retained between the lower surface of the outer cover 70 and the surface of the roll paper P2. Sufficient residence space can be provided.

  In the present embodiment, the configuration in which the outside air suction port 79 is formed on the lower surface of the external cover 70 has been described. However, the present invention is not limited to this configuration. For example, the outside air suction port 79 of the external cover 70 is connected to the external cover 70. It may be formed so as to open downstream in the paper conveyance direction.

  In the present embodiment, the relative position of the upper roller 46a and the lower roller 46b is changed by moving the upper roller 46a along the outer peripheral surface of the lower roller 46b to the upstream side in the paper conveyance direction. However, conversely, the lower roller 46b may be moved along the roller outer peripheral surface of the upper roller 46a to the downstream side in the paper conveying direction.

-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, a part of the drying air blown against the print paper P1 and P2 after image printing by the drying device 72 is discharged from the housing 6. The remaining drying air is blown out of the housing 6 through the air outlet 47, and the remaining drying air is blown out to the circulation space 80 of the outer cover 70 through the air outlet 49, so that the heating air is heated by the heater 74 and the high temperature dry air is exhausted from the air outlet It can be circulated by being led from 49 to the suction port 48. That is, when the air used for drying is taken from the outside of the housing 6, the temperature of the air is equivalent to room temperature, so it takes time to raise the temperature to obtain the necessary drying capacity, During that time, the print paper P1 and P2 cannot be dried, which causes a reduction in the processing capacity of the printer. However, like the present invention, the high-temperature drying air used for drying is circulated and taken into the drying device 72. As a result, the temperature can be raised to a required temperature in a short time compared with the case where the temperature is increased by taking in air at room temperature, and furthermore, since the heat energy required for the temperature increase can be reduced, the temperature of the drying air can be increased efficiently. be able to.

  As described above, the present invention provides a highly practical effect that can provide an ink jet printer capable of shortening the temperature rise time of the drying air without reducing the paper processing capacity. Therefore, 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 a top view which shows the structure of a discharge roller. It is sectional drawing seen from the housing | casing left side which shows the structure of a drying unit. It is the perspective view seen from the housing | casing front side which shows the structure around a discharge port. It is the perspective view seen from the downward direction of the housing | casing front side which shows the structure of an external cover. It is a side view which shows the drooping state of the front-end | tip part when roll paper is discharged | emitted. It is a side view which shows the state which changed the relative position of the upper roller and the lower roller.

Explanation of symbols

A Inkjet printer P1 Sheet paper P2 Roll paper H Print head 6 Housing 46 Downstream discharge roller 46a Upper roller 46b Lower roller 47 Discharge port 48 Suction port 49 Exhaust port 70 External cover (circulation flow path)
72 Drying equipment (drying means)
74 Heater (heating means)
79 Outside air intake 80 Distribution space

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 means disposed in the casing and drying the paper by blowing a drying air on the paper after image printing;
The casing is formed with an inlet for sucking air used for drying into the casing and an exhaust outlet for exhausting the drying air blown from the drying means to the outside of the casing,
Between the suction port and the exhaust port, a circulation flow path that guides the dry air exhausted from the exhaust port to the suction port is provided,
The drying means has a heating means for heating the air sucked through the suction port, and a part of the drying air heated by the heating means is blown out of the casing through the discharge port of the casing. On the other hand, an ink jet printer configured to blow the remaining dry air to the circulation flow path through the exhaust port. In claim 1,
The circulation channel is configured by an outer cover that covers the suction port and the exhaust port and has a circulation space inside,
The outer cover is formed with an outside air inlet for sucking air outside the outer cover into the circulation space.
The air sucked into the external cover through the outside air inlet and the dry air exhausted through the exhaust port are mixed in the circulation space of the outer cover, and the mixed air is mixed with the inlet. An ink jet printer, wherein the ink is sucked into the casing through the housing. In claim 2,
The outer cover is provided at a position above the outlet of the housing,
An outside air inlet of the outer cover is formed in the vicinity of the outlet, and dry air blown out through the outlet of the housing is sucked into the circulation space through the outside air inlet. Inkjet printer. In claim 2 or 3,
2. An ink jet printer according to claim 1, wherein an outside air inlet of the outer cover is formed so as to open downstream of the outer cover in the paper transport direction. In any one of Claims 1 thru | or 4,
A pressure-type discharge roller provided near the discharge port of the housing and having an upper roller and a lower roller facing the upper roller;
The discharge roller is a roll paper in which the paper after the image printing is wound in a roll shape, and a common tangent line on the roller surface of the upper roller and the lower roller has a predetermined angle with respect to the paper transport path. As described above, an ink jet printer configured to change the relative positions of the upper roller and the lower roller.

Images