JPH1110967A - Hot melt ink-jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high-speed printing by quickly heating a medium P to be recorded and quickly cooling the medium after printed with a hot melt ink. SOLUTION: A preheat platen 24 having a preheater 24a at a rear face and a main platen 26 having a main heater 26a are arranged via a transfer roller 25 at the upstream side and downstream side of a transfer route. A cooling platen 27 cooled by a first suction port 36 and a second suction port 37 where a cooling air can path, and a paper discharge roller 28 are set at the side lower than the main platen 26 of the transfer route. Front faces of the preheat platen 24, main platen 26 and cooling platen 27 are curved to project towards a nozzle head 13 and at the same time, the cooling platen 27 is urged by an urging spring 33 to project. During a printing operation, the cooling platen 27 kept at low temperatures comes in tight contact with a rear face of the medium P after printed by jetting of a hot melt ink. Cooling efficiency is accordingly enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer using hot melt ink, and more particularly, to a structure for heating and cooling a recording medium in the printer.

[0002]

2. Description of the Related Art Conventionally, in this type of printer, a recording head section comprising a nozzle head having a number of nozzles, an ink melting section having a heater, and a hopper section for receiving solid ink pellets is mounted on a carriage. The ink jet (hot melt ink) is ejected from the nozzles of the nozzle head while moving the carriage in a direction (main scanning direction) orthogonal to the transport direction of the recording medium such as paper, and the surface of the recording medium is ejected. It is configured to print characters, figures, etc.

When a drop of this type of hot-melt ink adheres to the surface of a recording medium having a low temperature, the droplet immediately solidifies on the surface, so-called ink fixability is poor, and the ink droplet There is a problem that a phenomenon such as dropping of a printed portion due to dropping occurs and good image quality cannot be obtained. Therefore, in the related art, a heater is provided on the back side of the platen or the like disposed opposite to the nozzle head to increase the temperature of the recording medium that is in contact with and supported by the platen. Similarly to the disclosed technology, a conveyance path between a conveyance roller on the conveyance upstream side and a discharge roller on the conveyance downstream side with the platen interposed therebetween is formed in a convex curved shape protruding in the nozzle head direction. Is formed so that the back surface of the recording medium easily adheres to the surface of the recording medium, thereby increasing the efficiency of heating the recording medium.

[0004]

However, in the case of printing with hot melt ink, the printed paper is sandwiched between a paper discharge roller and a pinch roller disposed downstream of the conveyance after printing. When feeding, if the attached hot melt ink is not solidified, the ink is transferred to the pinch roller or the like (image is taken), thereby causing a problem that the image quality is deteriorated.

On the other hand, if only the main platen facing the nozzle head is heated and the recording medium is moved before the temperature of the surface of the recording medium rises, the hot melt ejected from the nozzle head is moved. Since the fixing performance of the ink becomes poor, there is also a problem that the conveying speed of the recording medium and, consequently, the printing speed cannot be increased. Therefore, as a countermeasure, the transport distance from the transport roller to the paper discharge roller is increased, and the heating, printing, and cooling of the recording medium are completed during the long transport distance. With this configuration, there is a problem that the dimensions of the entire printer are increased.
In addition, if the conveying speed of the printed recording medium is increased, the time required for moving from the printing to the paper discharge roller (cooling time) is substantially shortened. The problem that image quality could not be obtained and therefore high-speed printing could not be performed could not be solved.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a compact hot-melt ink jet printer which does not degrade image quality even at high speed printing processing. Is what you do.

[0007]

According to a first aspect of the present invention, there is provided a hot-melt ink-jet printer according to the first aspect of the present invention, wherein a recording medium fed from a paper feeding unit is supplied to a hot-melt ink jet printer via a conveyance roller. Is conveyed along the surface of the main platen facing the nozzle head that ejects, and at least the main platen conveys the recording medium while heating the recording medium from the back side, from the nozzle head to the surface of the recording medium. In a hot melt ink jet printer configured to eject hot melt ink to form an image and then cool and discharge the paper via a paper discharge roller, the main platen,
The conveyance path of the recording medium to the cooling platen and the discharge roller is formed in a convex curve toward the nozzle head.

[0008] The invention described in claim 2 is the first invention.
In the hot melt inkjet printer described in the above, a pre-heat platen provided with auxiliary heating means is disposed in a conveyance path from an outlet of the paper feeding unit to the conveyance roller, while a conveyance path between the conveyance roller and the paper discharge roller Has a main platen provided with main heating means and a cooling platen, and the surfaces of the preheat platen, the main platen, and the cooling platen are formed in a convexly curved shape.

According to a third aspect of the present invention, in the hot melt inkjet printer according to the second aspect, the surface of the cooling platen has a convex curved transport path from the transport roller to the paper discharge roller. The surface of the cooling platen is pressed against the urging force on the back surface of the recording medium by the tension of the recording medium nipped between the conveyance roller and the paper discharge roller. It is what was constituted.

According to a fourth aspect of the present invention, in the hot melt ink jet printer according to the second or third aspect, a recording medium is pressed against a surface of one or both of the preheat platen and the main platen. For the purpose of the present invention.

[0011]

Next, embodiments of the present invention will be described. FIG. 1 is a perspective view of a hot melt ink jet printer according to the present invention, FIG. 2 is a side sectional view of the printer, FIG. 3 is a schematic plan view of a printing unit, and FIG. As shown in FIGS. 1 and 2, on the rear side of the upper surface of the main body case 1a of the printer 1, cut paper as a recording medium and transparent paper such as a transparent film for an overhead projector are stacked in a stacked state. A plurality of paper feed units 2 and 3 for setting are detachably mounted. As shown in FIG. 1, an operation panel unit 4 having various operation switches is provided on the right side of the upper surface of the main body case 1a.
In addition, a paper outlet 5 for discharging the recording medium P after printing is opened on the front surface of the main body case 1a, and the paper is discharged onto a paper discharge tray 6.

The openable and closable outer cover 7 shown in FIG.
The upper surface of the central opening 1b on the upper surface of the main body case 1a can be covered. Further, on the left side of the central opening 1b, yellow (Y) for a color ink jet printer,
An ink case 8 having a plurality of storage grooves 8a capable of storing respective magenta (M), cyan (C), and black (K) ink pellets (not shown) in a row is detachably mounted. The upper surface of the ink case can be opened by a cover body 9. Further, a transparent cover 10 (with a large number of exhaust holes 10a) fixed to the right side of an ink case 8 as an ink supply portion and protruding sideways can cover the right side of the central opening 1b.

As shown in FIG. 2 to FIG.
The recording head unit 11 mounted on the
A panel heater 14a which supports the nozzle head 13 on the lower surface side, and reciprocates ink passages and heats these passages.
On the back side, and a heater 15 on the back side
a, a melting hopper 16 also having a heater 16a on the back side, a lid panel 17 covering the back side of the front panel 14, the nozzle head 1
3 includes a control board for controlling a piezoelectric element for executing ink ejection, and a relay section 18 provided with a control board for controlling each heater.

The carriage 12 is mounted on the main body case 1a.
Inside, it is configured to be able to reciprocate along a guide mechanism 19 and a guide rail 20 in the sub-scanning direction along with a traveling mechanism (not shown). An ink (pellet) supply mechanism (not shown) is arranged below the front end of the ink case 8, the printing operation is performed, the ink is consumed, and the hot melt ink of a predetermined color in the ink tank 15 is disposed. When the remaining amount decreases and a sensor (not shown) detects that the ink has run out, the portion of the melting hopper 16 where the ink has run out is located in the portion of the ink case 8 where the ink pellet of the corresponding color is stored. Move the carriage 12 so that it is located below the exit, where:
A solid ink pellet of a predetermined color at normal temperature is dropped into the melting hopper 16. On the other hand, at the right end in the main body case 1a of the printer 1, hot melt ink is ejected from the nozzles of the nozzle head 13 onto the trial roll paper in a state where the carriage 12 is located at the corresponding position, thereby performing normal printing. A maintenance operation unit 21 for preventing nozzle clogging or the like during operation is disposed.

At the lower end of each paper feed unit 2, 3,
As shown in FIG. 2, a half-moon-shaped (D-shaped) sheet feeding roller 22 is provided.
a, 22b, and the recording media P stacked on each of the paper feed units 2, 3 or the manual recording media P from the manual feed trays 2a, 3a on the upper surface of each paper feed unit 2, 3.
To the transport path 29. As shown in FIG. 4, the conveyance path 29 includes a pair of registration rollers 23a and a pair of registration rollers 23b as a sheet feeding unit, a preheat platen 24, a conveyance roller 25 and a pinch roller 25a,
Main platen 26, cooling platen 27, discharge roller 2
8 and a pinch roller 28a, a paper discharge port 5, and a paper discharge tray 6, which are arranged in this order. As shown in FIGS. 4 to 6, as auxiliary heating means disposed on each back surface of the preheat platen 24 and the main platen 26. Of the recording medium P by the pre-heater 24a and the main heater 26a as the main heating means.
Is heated from its back surface. In addition,
The surface temperature of the preheat platen 24 is desirably set slightly higher than the surface temperature of the main platen 26.

The preheat platen 24, the main platen 26, and the cooling platen 27 are preferably made of a metal material having a high thermal conductivity, such as aluminum. At least the main platen 26 and the cooling platen 27
Is formed in a convex curved shape such as a circumferential surface with a radius R such that the surface thereof (the side facing the back surface of the recording medium P) approaches the nozzle head 13 side. As shown in the embodiment, the preheat platen 24 and the main platen 26 may be formed integrally. The preheat platen 24 may also be formed in a convex curved shape such as a circumferential surface having a radius R.

With these constructions, the conveying roller 25 and the pinch roller 25a pinch the conveying upstream side of the recording medium P, and the conveying downstream side of the recording medium P discharges the paper discharging roller 28.
When the recording medium P is conveyed while being tensioned between the preheat platen 24 and the main platen 26, the cooling platen 27
The entire back surface of the recording medium P is uniformly contacted and supported by the convex curved surface formed over the entire surface, so that heat transfer (heating) to the recording medium P in the heating area and the cooling area (the cooling platen 27 Heat absorption (cooling) on the surface or the like can be efficiently performed.

Polyether imide, polyamide imide,
A main platen 26 (preheat platen 24) supported by a support frame 30 made of a heat-resistant synthetic resin such as polyimide.
) Includes protrusions 3 on both left and right ends with screws 31.
0a (see FIG. 6A). Further, the cooling platen 27 disposed in the lower portion of the support frame 30 is attached to the projection 30b so as not to fall off by screws 32 fitted in the recesses 27a at both left and right end portions, and FIG.
As shown in (a), the minute distance H1 (0.1 mm in the embodiment)
Up to about 0.2 mm). Longitudinal direction of this cooling platen 27 (moving direction of carriage 12)
The back side of the middle part etc. along the bottom and the bottom plate 3 of the support frame 30
A biasing spring 33 such as a coil spring is interposed between the projection 30d and the projection 30d protruding from 0c, and the cooling platen 27 is projected and biased toward the nozzle head 13 (see FIG. 6B).

Accordingly, the conveying roller 25 and the pinch roller 25a pinch the conveying upstream side of the recording medium P, and the conveying downstream side of the recording medium P is pinched by the paper discharging roller 28 and the pinch roller 28a, and the When the medium P is conveyed while applying tension, the entire surface of the cooling platen 27 along the conveyance direction can be pressed exactly against the back surface of the recording medium P, and the recording medium P moves from the recording medium P to the cooling platen 27 side. Heat transfer can be performed efficiently. The rotation speed of the discharge roller 28 is set to be faster than the rotation speed of the transport roller 25.
The pinching force between the sheet discharging roller 28 and the pinch roller 28a is set to be weaker than the pinching force between the transport roller 25 and the pinch roller 25a, so that the sheet discharging roller 28 slips by the speed difference. . However, even if the holding force on the paper discharge roller 28 side is set to be weak, the recording medium P does not rise from the transport path due to the urging force of the cooling platen 27 (the elastic force of the urging spring 33). Needless to say, it has a holding force of a degree that can be suppressed. Further, as shown in FIG.
6, the main baffle 43 as a resilient piece pressing the free end against the surface of the preheat platen 24 and the pre-baffle 44 as a resilient piece pressing the free end against the surface of the preheat platen 24 further ensure the pressing action of the recording medium P. The baffles 43 and 44 are made of a heat-resistant synthetic resin material such as a polyimide film having heat resistance and elasticity. Although it is desirable to arrange the elastic members against the surfaces of the platens 24 and 26, only one of the elastic members may be used.

A suction port and a cooling platen 27 are provided downstream of the main platen 26 provided with a main heater 26a as a main heating means on the back side, and disposed on the back side of the platens 26, 27. Suction fan 35
Thus, cooling air is introduced from the discharge port 5 side toward the cooling platen 27. That is, as shown in FIGS. 2, 4, 6A and 6B, the frame frame 3 disposed below the transport path 29
The suction fan 35 is arranged in the frame 4, and the support frame 30 is attached to the upper front portion of the frame 34. By disposing a predetermined distance between the transport downstream end of the main platen 26 fixed to the support frame 30 and the transport upstream end of the cooling platen 27, the second port as one of the suction ports is provided. One suction port 36 is formed longitudinally along the sub-scanning direction of the carriage 13. The first suction port 36 has an elongated heat-insulating partition wall made of a heat-resistant synthetic resin that thermally isolates the downstream end of the main platen 26 from the transport and the upstream end of the cooling platen 27 from the transport. 38 are arranged.

On the other hand, another suction port is provided between the lower surface of the downstream end portion of the cooling platen 27 and the wall plate 30e of the support frame 30 at appropriate intervals along the sub-scanning direction of the carriage 13. And a plurality of second suction ports 37 are formed.
The second suction port 37 is disposed between the paper discharge rollers 28 having an appropriate length (for example, only the support shaft 28b of the paper discharge rollers 28).
Are formed at a plurality of locations.

An air passage 39 communicating with the first suction port 36 and the second suction port 37 and guiding cooling air to the suction fan 35 is formed in the bottom plate 30c of the support frame 30 (see FIG. 2). FIG. 6A and FIG. 6B). further,
Exhaust ports 40 and 41 are opened on the rear surface and the like of the frame 34, and a power supply substrate 42 is disposed in the frame 34 between the exhaust ports 40 and 41 and the suction fan 35 (FIG. 2). reference). A light transmission type for discriminating the type of the recording medium P between the plain paper and the transparent paper such as a transparent film for an overhead projector is provided in a transport path 29 between the registration roller pair 23b and the preheat platen 24. And outputs a detection signal for control such as a change in the temperature condition of the heater as described later.

Next, a control system in the hot-melt ink jet printer having the above configuration will be described with reference to a block diagram shown in FIG. The CPU 50 includes a ROM 51
According to various control programs stored in advance in
Based on the print data sent from the host computer, it executes various arithmetic and control operations necessary for printing a color image, and is for driving the nozzle head 13 based on the print data. A print head drive circuit 62, a carriage drive circuit 63 for driving a carriage motor 60 for reciprocating the carriage 13 in the main scanning direction, a heater control circuit 64 for controlling the energization of the pre-heater 24a and the main heater 26a,
A fan driving circuit 65 for driving the suction fan (cooling fan) 35; rotating the transport roller 25 and the discharge roller 28 in the paper transport direction during normal rotation; and selecting an ink supply mechanism or a maintenance mechanism during reverse rotation. The conveyance system drive circuit 66 for driving the paper feed motor 61 as one drive source for selectively operating the recording medium P by selectively operating one of the paper feed rollers 22a and 22b. A paper feed system drive circuit 67 for driving a paper feed solenoid 68 for sending out to the path is connected to each other, and a pre-thermistor 69 for detecting the temperature of the pre-heat platen 24 and the main platen 26
A predetermined control signal is output to the heater control circuit 64 or the fan drive circuit 65 based on various detection signals and the like input from the main thermistor 70 for detecting the temperature of the optical sensor 45 and the optical sensor 45. It is configured to be.

In the ROM 51, in addition to storing various control programs, the control temperature of the preheat platen 24 or the main platen 26 is stored and set according to the type of the recording medium P and the printing resolution. R
The AM 52 is temporarily used as a work area for temporarily storing print data sent from the host computer and executing various control operations.

Next, the operation of heating and cooling the recording medium P by the above configuration will be described. When a power switch (not shown) of the printer 1 is turned on, a printing operation standby state is established, and current is supplied to the pre-heater 24a and the main heater 26a. Is conducted to start preparation for heating, and the suction fan 35 also rotates. As a result, in the printing operation standby state, since the first suction port 36 is not blocked by the recording medium P, the cooling air taken in from the paper discharge port 5 It is guided to the downstream side of the conveyance of the cooling platen 27, enters the support frame 34 from both the first suction port 36 and the second suction port 37, and is blown out through the suction fan 35 in the frame 34. The air flows along the surface of the power supply board 42 to remove heat, and
The air is exhausted to the outside of the main body case 1a through 0 and 41. In the printing operation standby state, the number of rotations of the suction fan 35 is set lower than during the printing operation, and the power supply to the pre-heater 24a and the main heater 26a is reduced to reduce power consumption.

Next, when the printing operation starts, the preheater 2
4a and a predetermined electric power to the main heater 26a,
The preheat platen 24 and the main platen 26 are maintained at a predetermined temperature. Then, when the type of the recording medium P is selected and a paper feeding instruction is issued, a predetermined paper feeding roller 22a or 22b is driven to rotate, and the leading end of the recording medium P to be printed is once shifted by the registration rollers 23a or 23b. Where
After being stopped and the attitude of the front edge in the transport direction is adjusted, the paper is transported in the direction of the transport roller 25.

The recording medium P is pressed against the surface of the pre-heat platen 24 by a pre-baffle 44 as a resilient piece, receives a preheating action, and then pressed against the surface of the main platen 26 by a main baffle 43. While receiving this heating effect. When the leading end of the recording medium P closes the first suction port 36, the back surface of the recording medium P does not rise from the convex curved surface of the main platen 26 due to the suction effect. Can be reliably received.

In this way, the recording medium P conveyed while being brought into contact with and supported on the surfaces of the platens 24 and 26 is heated to a predetermined temperature, and is ejected from the nozzle head 13 at a position facing the main platen 26. Make it easy for hot melt ink to adhere. Next, when the recording medium P is nipped at the location of the paper discharge roller 28, the first suction port 36 is closed by the recording medium P, and there is almost no inflow of air from this location, and the cooling platen A large amount of cooling air is sucked into the support frame 34 from the second suction port 37 on the back surface side of the support frame 27.

The printed portion of the recording medium P sandwiched between the location of the transport roller 25 and the location of the paper discharge roller 28 is a portion of the cooling platen 27 which is projected and urged via an urging spring 33. Since it is in close contact with the convex curved surface (see FIG. 6B), the entire surface of the cooling platen 27 along the transport direction can be pressed exactly against the back surface of the recording medium P, and Cooling platen 27
Heat transfer to the transfer path 2
9 is a preheat platen 24, a main platen 26,
The cooling platen 27 has a smooth convex curved shape, and the recording medium P can be stably conveyed without causing a phenomenon such as floating when the recording medium P is in close contact with the surface of these platens. It is possible.

As described above, the temperature of the cooling platen 27 rapidly decreases, and the heat can be quickly removed from the recording medium P discharged in close contact with the surface thereof. Even if the conveying distance is short until the pinch roller 28a is nipped, or if the printing speed is increased to increase the main scanning direction speed (conveying speed) of the recording medium P, the attached hot melt ink is Solidification does not occur on the surface of the pin roller 28a of the paper discharge roller 28, so that the image quality does not deteriorate. Even when high-speed printing is performed, the fixability of a printed portion is improved and the image quality does not deteriorate.

The first suction port 36 is provided with a heat insulating partition 3.
By disposing the cooling platen 8, the cooling platen 2, such as heat radiation from the main platen 26, which must maintain a high temperature
7, the temperature of the cooling platen 27 can be reliably kept low. In the embodiment, when printing on plain paper, the surface temperature of the main platen 26 is set to 68 ° C. and the resolution is set to 60 dpi at a resolution of 300 dpi.
When printing on a transparent film for overhead projects with a surface temperature of 65 ° C at 0 dpi, a resolution of 60
The surface temperature is set to 80 ° C. at 0 dpi. As described above, when it is desired to change the type of the recording medium P and the printing conditions, the temperature of the main platen 26 during printing must also be rapidly changed.

For example, when changing the above conditions or the like, particularly when it is desired to rapidly lower the temperature of the main platen 26, the cooling air sucked from the first suction port 36 is used to supply the main platen 26 with the cooling air. It is necessary to increase the cooling effect. Therefore, when the first suction port 36 is not closed by the recording medium P, the rotation speed of the suction fan 35 is increased, and the heat insulating partition 38 is disposed in the first suction port 36. , Main platen 26
In the narrow flow path between the downstream edge of the conveyance and the heat insulating partition wall 38, the flow velocity of the sucked air is increased, and the cooling effect on the main platen 26 can be improved. By making the shape of the gap between the main platen 26 and the heat insulating partition 38 narrower on the suction inlet side and wider on the inner side of the support frame 34, the cooling effect can be further improved.

In the above-described embodiment, the preheat platen 24 is brought into contact with the back side of the recording medium P in the same manner as the main platen 26 to perform preheating. It is not necessary to make contact with the recording medium P. For example, the recording medium P may be brought into contact with the front side (the side to which ink adheres), or at least two preheat platens are provided so as to come into contact with both front and back surfaces. May be. In particular, when a concave pre-heated platen is provided so as to be in contact with the surface side of the recording medium P, the surface on which the ink adheres can be efficiently heated.

The preheat platen 24 does not necessarily have to have a width equal to or longer than the width of the recording medium P in the main scanning direction. In the case of a preheat platen having a slightly shorter width in the main scanning direction, or a case where the preheating platen is intermittently installed in the main scanning direction, the effect of the preheating is sufficient. Can be played.

[0035]

As described in detail above, the hot melt ink jet printer according to the first aspect of the present invention transfers the recording medium sent from the paper feeding unit via the transport roller.
The hot melt ink is conveyed along the surface of the main platen facing the nozzle head that ejects the hot melt ink, and the recording medium is conveyed while being heated at least from the back side of the main platen, and the surface of the recording medium is In a hot melt ink jet printer configured to eject hot melt ink from a nozzle head to form an image, then cool and discharge the paper via a paper discharge roller, a main platen, a cooling platen, and a paper discharge roller from the transport roller The conveyance path of the recording medium up to this is formed in a convex curve toward the nozzle head side.

As described above, when the transport path is formed in a convexly curved shape, the recording medium transported along this path is brought into close contact with each surface of the main platen and the cooling platen over a wide area without floating. As a result, the heating effect and the cooling effect on the recording medium can be improved. As a result, the printing speed can be increased, and the transport speed of the recording medium can be increased. Further, even if the transport distance from the transport roller to the paper discharge roller is shortened, the effect of heating and cooling the recording medium during the interval is high, so that the printer can be made compact.

Further, the invention described in claim 2 is the same as that in claim 1
In the hot melt inkjet printer described in the above, a pre-heat platen provided with auxiliary heating means is disposed in a conveyance path from an outlet of the paper feeding unit to the conveyance roller, while a conveyance path between the conveyance roller and the paper discharge roller Has a main platen provided with main heating means and a cooling platen, and the surfaces of the preheat platen, the main platen, and the cooling platen are formed in a convexly curved shape.

In addition to the main platen, the surface of the preheat platen on the upstream side of the conveyance is also formed in a convexly curved shape. And heating by the auxiliary heating means provided in the pre-heat platen, the recording medium can be brought close to a predetermined temperature from a position before the printing unit, and the printing speed and the conveying speed can be further increased. This has the effect that the speed can be increased.

Further, according to a third aspect of the present invention, in the hot melt ink jet printer according to the second aspect, the cooling platen has a surface having a convex curved conveying path from the conveying roller to the paper discharge roller. The cooling platen is pressed against the back surface of the recording medium against the urging force by the tension of the recording medium nipped between the transport roller and the paper discharge roller. It is composed.

Although it is difficult to arrange a cooling platen separate from the main platen so as to have a convex curved surface as described above and to coincide with the convex curved transport path, it is difficult. As in the present invention, the cooling platen is urged to project beyond the convexly curved conveyance path, and the tension of the recording medium sandwiched between the conveyance roller and the paper discharge roller causes
If the surface of the cooling platen is configured to be pressed against the urging force on the back surface of the recording medium, the surface of the low-temperature cooling platen and the heated recording medium can be exactly fitted over a wide range. It is extremely easy to achieve close contact, and the effect of cooling the recording medium can be further ensured. Then, the cooling platen surely contacts the back side of the printed recording medium,
Since the temperature of the recording medium can be efficiently and quickly lowered, there is an effect that even when the printing is performed at a high speed, the ink is not transferred on the discharge roller side, and the image quality is not reduced.

According to a fourth aspect of the present invention, in the hot melt ink jet printer according to the second or third aspect, a recording medium is pressed against a surface of one or both of the preheat platen and the main platen. For the purpose of the present invention. With this configuration, the recording medium is heated even in a state in which the downstream side of the conveyance is a free end, and in a state in which the recording medium is nipped by the conveyance roller and the discharge roller and tension is applied to the recording medium. This makes it possible to ensure the contact with the platen surface at the portion where the recording medium is to be formed, and to easily set the recording medium at a predetermined temperature.

[Brief description of the drawings]

FIG. 1 is a perspective view of a printer.

FIG. 2 is a sectional view of the printer.

FIG. 3 is a schematic plan view illustrating a positional relationship between a carriage, an ink supply unit, and the maintenance operation unit.

FIG. 4 is an enlarged cross-sectional view of a main part of a transport path.

FIG. 5 is a side view of a main platen, a cooling platen, and a support frame.

6A is a sectional view taken along the line VIA-VIA in FIG. 3, FIG.
4 is a sectional view taken along the line VIB-VIB in FIG.

FIG. 7 is a block diagram of a control system.

[Explanation of symbols]

 P Recording medium 1 Printer 5 Paper discharge port 11 Recording head unit 12 Carriage 13 Nozzle head 25 Transport roller 26 Main platen 27 Cooling platen 28 Discharge roller 29 Transport path 30 Supporting frames 31, 32 Screw 33 Urging spring 34 Frame frame 35 suction fan 36 first suction port 37 second suction port 38 heat insulating partition

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuya Asano 15-1, Naeshiro-cho, Mizuho-ku, Nagoya-shi Inside Brother Industries, Ltd. (72) Inventor Naoya Kamimura 15-1 Naeshiro-cho, Mizuho-ku, Nagoya-city Inside the company (72) Inventor: Taku Nakata 15-1 Naeshiro-cho, Mizuho-ku, Nagoya

Claims (4)

[Claims] 1. A recording medium fed from a paper feeding section is conveyed via a conveying roller along a surface of a main platen facing a nozzle head for ejecting hot melt ink, and the recording medium is conveyed by at least the main platen. The recording medium is conveyed while being heated from the back side thereof, and the hot melt ink is ejected from the nozzle head onto the surface of the recording medium to form an image, and then cooled and discharged via a discharge roller. In the configured hot melt ink jet printer, a conveyance path of the recording medium from the conveyance roller to a main platen, a cooling platen, and a discharge roller is formed in a convex curved shape toward the nozzle head side. Hot melt inkjet printer. 2. A pre-heat platen provided with an auxiliary heating means is disposed on a transport path from an outlet of a paper feeding section to a transport roller, while a main path is provided on a transport path from the transport roller to a discharge roller. A main platen with heating means,
2. The hot melt inkjet printer according to claim 1, wherein a cooling platen is arranged, and each surface of the preheat platen, the main platen, and the cooling platen is formed in a convex curved shape. 3. The recording platen, wherein the surface of the cooling platen is urged so as to protrude beyond a convexly curved conveyance path from a conveyance roller to a paper ejection roller, and is held between the conveyance roller and the paper ejection roller. 3. The hot melt inkjet printer according to claim 2, wherein a surface of the cooling platen is pressed against a back surface of the recording medium against the urging force by a tension of the medium. 4. The hot melt according to claim 2, wherein an elastic piece for pressing a recording medium is disposed on a surface of one or both of the preheat platen and the main platen. Inkjet printer.