JPH1128811A - Hot melt ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot melt ink jet printer in which the outer air is not sucked into a nozzle head even during a bubble removing work. SOLUTION: A head is moved to a high speed heating position (S1), a heater is operated (S2), the head is heated up to a specified temperature (S3), moving speed of the head is switched lower than a normal level (S4) and then the head is moved to a purging position (S5). Consequently, the joint of a return path for sucking ink at the time of purging to a subchamber for storing the ink is opened gradually from closed state and a high negative pressure is not generated in the return path. According to the arrangement, a meniscus formed at the ink jet port of the nozzle head is not broken and the outer air can be prevented from being sucked into the nozzle head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of hot melt ink jet printers.

[0002]

2. Description of the Related Art The head of a conventional hot-melt ink-jet printer (hereinafter sometimes simply referred to as a printer) has a hot-melt ink X as shown in FIG.
The main chamber PA2 and the sub-chamber PA, which can be heated and melted and stored (hereinafter sometimes simply referred to as ink).
3, an ink tank PA1 including a communication path PA4 provided by making a hole in a partition wall between the main chamber PA2 and the sub chamber PA3, a nozzle head PA5 for spraying ink X onto a recording medium, and a main chamber. An ink supply path PA6 connecting PA2 to the nozzle head PA5; an ink supply path PA7 connecting the sub-chamber PA3 to the nozzle head PA5;
A6 and a deaerator PA8 provided along the PA7.

[0003] The air pressure in the main chamber PA2 is always maintained at the atmospheric pressure, and the pressure is increased by operating the compressor PA22 communicating with the air pressure adjusting port PA21.

[0004] The sub chamber PA3 has an ink supply port PA31 communicating with the ink supply device PA32, and the ink X is supplied as appropriate. Further, dust in the ink X is removed by a filter PA33 provided near the ink supply port PA31.

[0005] The communication path PA4 extends from the sub chamber PA3 to the main chamber PA.
One-way valve P that allows ink X to pass only in the direction toward
A41 is provided so that the ink X does not flow backward through the communication PA4.

[0006] The deaerator PA8 includes an air permeable thin film PA81 which forms the wall surfaces of the ink supply paths PA6 and PA7, and a negative pressure generator PA82 for sucking bubbles in the ink X.

Since the melting point of the hot melt ink X is much higher than room temperature, it solidifies when the printer is not operating. Since the volume decreases during the solidification, gaps are formed in the ink supply paths PA6 and PA7 and the like. Then, when the ink is melted by the operation of the printer, the air collected in the gap becomes bubbles and is taken into the ink X. When these bubbles are ejected from the nozzle head PA5 together with the ink X, the ejection amount of the ink X is reduced by the amount of the bubbles, and printing is not performed correctly.

Therefore, when the printer is started or the like, the inside of the main chamber PA2 is pressurized by the compressor PA22 to forcibly transfer the ink X to the sub chamber PA3 via the ink supply path PA6, the nozzle head PA5, and the ink supply path PA7. This is to circulate and drive bubbles existing in the ink supply paths PA6 and PA7 and the like to the sub chamber PA3.

[0009] When this operation is completed, the printer is put into a normal operating state, and a printing operation is performed. When the head is moved right and left during printing or the like, an inertial force acts on the ink X, and the ink X flows into the main chamber PA2 due to the property of the one-way valve PA41. h occurs. The ink supply path PA6, the nozzle PA5, and the ink supply path PA7 are caused by the pressure difference due to the liquid level difference h.
, The ink X is slowly circulated to the sub-chamber PA3.

However, the ink X from the nozzle head PA5
Is ejected, the ink supply paths PA6 and P6
Since the suction force acts on both A7, the ink X flows backward from the sub-chamber PA3 to the nozzle head PA5, and the air bubbles that have been driven to the sub-chamber PA3 are also guided to the nozzle head PA5.

Therefore, it is necessary to constantly suck and remove the bubbles by the deaerator PA8 so that the bubbles flowing backward do not reach the nozzle PA5.

However, in such an apparatus, the size of the apparatus is increased due to the installation of the deaerator, and complicated control for making a difference in liquid level between the main chamber and the sub chamber is required to circulate the ink. There was a problem.

Therefore, there is provided a valve for opening and closing both the nozzle head side communication hole and the main chamber side communication hole provided in the sub chamber,
There has been proposed an apparatus having a mechanism for closing the communication hole on the main chamber side to open the communication hole on the nozzle head side when removing bubbles, and closing the communication hole on the nozzle head side and opening the communication hole on the main chamber side during printing.

According to this apparatus, since only one of the inlet and the outlet of the sub-chamber is always open, no air bubbles are sent into the main chamber at the time of air bubble removal, and air bubbles are sent to the nozzle head side at the time of printing. There is no backflow of the contained ink.

[0015]

However, in the above-mentioned conventional apparatus, when the communication hole on the nozzle head side is suddenly opened at the time of air bubble removal, the ink flow connecting the nozzle head and the communication hole on the nozzle head side is reduced. In some cases, a negative pressure was generated in the road, and outside air was sucked from the nozzle.

That is, there is residual ink generally called a meniscus in the nozzle, and this meniscus plays a role of separating the outside air from the inside of the nozzle head. It is sucked inside.

When the outside air is sucked into the nozzle head as described above, there is a problem that a change in pressure in the ink discharge passage in the nozzle head due to a change in the piezoelectric element is not transmitted to the ink, so that the ink cannot be discharged.

Therefore, the present invention solves the above problems,
It is an object of the present invention to provide a hot-melt ink jet printer that does not suck outside air into a nozzle head even during a bubble removing operation.

[0019]

According to a first aspect of the present invention, there is provided a hot-melt ink jet printer in which a head main body is placed on a surface of a recording medium in a printer frame in a discharge direction of the recording medium. A hot-melt ink jet printer that performs printing by discharging hot-melt ink that has been heated and melted onto the recording medium while moving the head body in a vertical horizontal direction along the horizontal direction, wherein the head body is reciprocally movable in the horizontal direction. An ink tank supported by the carriage, comprising a main chamber and a sub-chamber for storing hot-melt ink melted by heating, and a communication passage connecting the main chamber and the sub-chamber. A nozzle head attached to the main chamber via a support member, and for discharging the hot melt ink to a recording medium; From the nozzle head to the sub-chamber for returning the hot-melt ink to the sub-chamber, and connecting the sub-chamber and the return path. An ink return hole, and valve means for opening and closing an ink supply hole connecting the sub-chamber and the communication path; and engaging the valve means to move the valve means to the open position of the ink return hole or the ink supply hole. Cam means for moving to the closed position, and the printer for moving the valve means to the open position of the ink return hole by the cam means when the carriage is moved to the return processing position and in contact with the cam means. A frame-side abutting member, when the cam means moves the valve means to the open position of the ink return hole, at least the cam means Serial during contact start of the abutting member, characterized in that a decelerating means for decelerating the moving speed of the carriage.

According to the hot melt ink jet printer of the first aspect, when the carriage is moved to the return processing position in order to perform the return processing of the hot melt ink from the nozzle head to the sub-chamber, the hot spot on the printer frame side. The contact member comes into contact with the cam means and engages the cam means with the valve means. As a result, the valve means moves to open the ink return hole connecting the sub-chamber and the return path and close the ink supply hole connecting the sub-chamber and the communication path. Therefore,
Bubbles taken in when the ink remaining in the nozzle head is solidified are transported from the nozzle head to the sub-chamber through the return path together with the remaining ink, and are removed.

When the ink return hole is opened, the moving speed of the carriage is reduced by the speed reducing means at least at the start of contact between the cam means and the contact member. The holes do not suddenly open, the negative pressure generated in the return path is kept low, the meniscus formed in the ink ejection holes of the nozzle head is not broken, and outside air can be sucked into the nozzle head. Absent.

According to a second aspect of the present invention, there is provided the hot melt inkjet printer according to the first aspect, wherein the valve means has a mechanism for opening and closing the ink return hole by turning. Features.

According to the hot melt ink jet printer according to the second aspect, the ink return hole is opened and closed by rotating the valve means, so that the ink return hole is gradually opened. No large negative pressure is generated in the return path.

According to a third aspect of the present invention, in the hot melt inkjet printer according to the first or second aspect, the moving speed at the time of deceleration is such that the ink return hole is opened. Accordingly, the speed is such that the negative pressure generated in the return path is suppressed to a level that does not destroy the meniscus due to the ink formed at the ink ejection port of the nozzle head.

According to a third aspect of the present invention, when the cam means moves the valve means to the open position of the ink return hole, the moving speed of the valve means is reduced when the ink return hole is opened. By doing so, the negative pressure generated in the return path is controlled so as not to destroy the meniscus due to the ink formed at the ink discharge port of the nozzle head, so that outside air is not sucked from the ink discharge port.

According to a fourth aspect of the present invention, there is provided the hot melt inkjet printer according to any one of the first to third aspects, wherein the speed reducing means includes the cam means and the contact member. The deceleration is started at a predetermined timing before the contact.

According to the hot melt ink jet printer described in claim 4, when the cam means moves the valve means to the open position of the ink return hole,
Instead of being decelerated to a predetermined speed in all periods, the deceleration by the deceleration means is started from a predetermined timing before the contact between the cam means and the contact member is performed. Until the timing is reached, the carriage is moved at a normal moving speed, and the time required for the return processing is reduced.

[0028]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the inside of a hot-melt ink jet printer (sometimes simply called a printer) 100 according to an embodiment of the present invention.

Referring to FIG. 1, a printer 100 includes a transport roller 105, which is driven by a transport motor 106 and transports a recording paper R as a recording medium to an upper portion of the printer 100 in a housing 103 thereof. In the transport route,
The head 1 supported on the carriage 107 is provided. The carriage 107 is supported by a support member 109 fixed to the housing 103 so as to be reciprocally movable in a direction orthogonal to the conveying direction of the recording paper R as indicated by arrows X1 and X2. 110 is fixed to a timing belt 111 driven by
It is reciprocally movable in the X2 direction.

Next, the head 1 of the hot melt ink jet printer 100 according to the present embodiment will be described in detail.

As shown in FIG. 2, the head 1 includes an ink tank 10, a front panel 30, a melting tank 40, a cam 50, and a control board stage 70.

The ink tank 10 includes a front panel 30
And a hot melt ink (hereinafter sometimes simply referred to as ink).
And four sets of main chambers 11 and sub-chambers 13 for color output (yellow, magenta, cyan, and black), an ink tank cover 19, and an ink tank attached to the back of the ink tank 10. And a heater 17, and further, as shown in FIG.
A communication path 21 that opens downward is provided on the back side of the bottom surface of each of the main chamber 11 and the sub chamber 13 indicated by the dotted line 0.

As shown in FIG. 3, the main chamber 11 has an L-shape when viewed from above, and has a main chamber entrance 21a leading to the communication passage 21 and a main chamber exit leading to the front panel 30. 22 a and a filter 29.

The filter 29 is manufactured by sintering stainless steel fibers into a paper shape and then pressing the fibers. Each filter is bent in a complicated manner and overlapped, and a large number of layers are formed in the thickness direction. Which has a three-dimensionally structured passage.

The sub-chamber 13 has a sub-chamber outlet 21b leading to the communication passage 21 and a sub-chamber inlet 22b leading to the front panel 30.
As shown in FIG. 2, the sub chamber outlet 21b and the sub chamber inlet 2
When one of 2b is closed, the other is opened.
A valve opening / closing lever 24 as a V-shaped valve means is provided.

The valve opening / closing lever 24 is made of an aluminum alloy die-cast. As shown in FIGS. 7 and 8, the lever base 25 provided between the sub chamber outlet 21b and the sub chamber inlet 22b is used as a support point. It is mounted so that it can swing. The valve opening / closing lever 24 is provided with pressure-contact valves 27 and 28, and is normally urged by a leaf spring 26 so that the pressure-contact valve 28 normally closes the sub chamber inlet 22b. Here, the pressure contact surface of the pressure contact valve 27 is spherical, the edge of the corresponding sub-chamber outlet 22b is tapered, and the pressure contact surface of the pressure contact valve 28 is planar, and the corresponding port of the sub-chamber inlet 22b. The edge has an annularly protruding shape. The pressure-contact valves 27 and 28 are made of silicone rubber and have a Shore hardness of about 40 ° and a heat-resistant temperature of about 200 ° C.
It is.

As shown in FIG. 2, the ink tank upper cover 19 includes a front panel cover 19a conforming to the shape of the front panel 30, a sub-chamber cover 19b for covering the sub-chamber 13, and a valve opening lever 24. A long hole 19c for exposing the upper end portion 24a and the sub chamber 13 from the melting tank 40 are provided.
Ink inlet 1 for supplying hot melt ink
9d, an air chamber 20 for sending compressed air from a compressor (not shown) to each main chamber 11, a through hole 20b communicating from the compressor to the air chamber 20, and an air chamber lid 20a for sealing the air chamber 20. I have. In addition, the air chamber 20 of the ink tank upper lid 19 is provided with a through hole 23 communicating with the main chamber 11 as shown in FIG.

As shown in FIG. 4B, which shows a sectional line AA in FIG. 4A, the ink tank heater 17 has a thickness of 55 μm so as to close the communication passage 21 of the ink tank 10.
A heater 17a is attached, and a thickness 55
In this example, a DC heater 17b having a thickness of μm is laminated and attached, and an insulating sheet 17c made of polyimide having a thickness of 25 μm is laminated and attached to the outside.

The AC heater 17a is made of a 25 μm-thick polyimide insulating sheet provided with a 30 μm-thick electric resistance wire formed so as to meander an etched stainless steel pattern and a thermistor as a temperature sensor. ing. The electric resistance line is formed in a pattern that avoids the communication path 21 indicated by the dotted line.

Like the AC heater 17a, the DC heater 17b has a thickness of 25 μm with an electric resistance wire 18c formed in an etched stainless steel pattern having a thickness of 30 μm.
It is made of an insulating sheet of μm polyimide. And it is formed in the pattern which avoids the part of the communication path 21.

The front panel 30 has four nozzle heads 31 on the front surface as shown in FIG. 2, and the nozzle heads 31 from the main chambers 11 on the back surface as shown in FIG.
Each sub-chamber 1 from the outward path 35 leading to
A return path 37 leading to 3 is formed. Further, as shown in FIG.
A cover panel 30a is attached so as to cover the return path 37, and a front panel heater 33 is attached to the cover panel 30a. As shown in FIG. 5, an outward entrance 35 a is provided from each main chamber 11 to each outward path 35.
Outgoing path exit 35b from each outgoing path 35 to each nozzle head 31
However, from each nozzle head 31 to each return path 37, the return path entrance 3
7b is a return exit 37a from each return 37 to each sub-chamber 13.
Are provided respectively.

The nozzle head 31 has a flow path for ink therein as shown in FIG. The ink flows in the ink flow path as indicated by the arrows shown in FIG.
5b and the lower branch point 31a to reach the nozzle 32,
Further, the air can be circulated to the sub-chamber 13 via the upper branch point 31b, the return path entrance 37b, and the return path 37. Further, the nozzle 32 is configured by arranging 128 fine ejection ports in two rows of 64 nozzles each time. Shoot to the mound.

As shown in FIGS. 6 and 7, the cam 50 is mounted on the ink tank top cover 19 with a slidable member in the left and right direction in the figure. It protrudes from above the upper lid 19. In addition, the cam 50 has four cam surfaces 50b, and a force for pushing the cam 50 in the direction of arrow A shown in FIG.

The control board stage 70 has a control board (not shown) and is mounted on the head 1.

As shown in FIG. 1, the head 1 having such a configuration can be reciprocated in directions A and B by a carriage motor 110. The moving range of the head 1 includes a high-speed heating position for turning on the power of the AC heater 17a and the panel heater 33 for rapidly ripening the head 1, a purging position for performing purging, and a head 1 during the operation of the printer. There is a home position where the player normally stands by. In the printer of the present embodiment, the high-speed heating position is set to the left end, the purging position is set to the right end, and the home position is set to a predetermined position between the high-speed heating position and the purging position. During operation of the printer, the DC heater 1
7b and the like are assumed to be constantly operating.

Next, the purging process in this embodiment will be described. First, a command is output to a drive circuit (not shown) to drive the carriage motor 110 to move the head 1 to the purging position at the right end of the printer body. Then, as shown in FIG.
a is pressed against the frame 54 of the printer body. Then, the cam 50 slides on the ink tank cover 19 in the direction of arrow A. When the cam 50 slides in the direction of arrow A, the cam surface 50b pushes the upper end 24a of the valve opening / closing lever 24 in the direction of arrow D shown in FIG. Then, the valve opening / closing lever 2
4 swings around the lever pedestal 25 as a fulcrum, the pressure contact between the press-contact valve 28 and the sub-chamber inlet 22b is released, and when the swing further proceeds, the press-contact valve 27 and the sub-chamber outlet 21b press against each other, and the sub-chamber inlet 22b is closed. When opened, the sub chamber outlet 21b is closed.

Next, purging, which is a process of returning hot melt ink, is performed. Purging is an operation of dissolving the solidified ink remaining in the front panel 30 and the nozzle head 31 and pushing out the air bubbles taken in when the ink is solidified together with the remaining ink into the sub chamber 13. Specifically, air bubbles are extruded as follows. First, the pump 881 is driven by the pump control circuit 88 and the through hole 2
0b from the main chamber 11 via the air chamber 20 and the through hole 23.
The air in the main chamber 11 is raised by sending air into the inside. The sub chamber outlet 21b is sealed, and the sub chamber inlet 22
Since b is open, the ink containing air bubbles flows from the main chamber 11 to the main chamber outlet 22a, the outward entrance 35a, and the outward path 3a.
5. Outbound exit 35b, nozzle head 31, inbound entrance 37
b, the return path 37, the return path exit 37a, and the sub-chamber 13 via the sub-chamber inlet 22b.

Next, it is determined whether the purge control has been performed twice. If the purge control has been performed only once, a command is output to a drive circuit described later to drive the carriage motor 110 to move the head 1 to the purging position. Slightly shift from.
Then, the contact surface 50b of the cam 50 separates from the frame 54 of the printer body.

In the process of moving the head 1, the cam 5
Engagement recess 50c provided near the contact surface 50a
And the leaf spring 60 provided on the frame 54 are engaged with each other,
The cam 50 relatively moves in the arrow B direction.
As a result, the upper end 24a of the valve opening / closing lever 24 is no longer pressed by the cam surface 50a, and the valve opening / closing lever 24
Swings around the lever pedestal 25 as a fulcrum by the urging force of the leaf spring 26, the pressure contact between the press-contact valve 27 and the sub-chamber outlet 21b is released, and when the swing further advances, the press-contact valve 28 and the sub-chamber inlet 22b press against each other. Then, the sub-chamber inlet 22b is closed and the sub-chamber outlet 21b is open, and leveling is performed. Leveling is an operation in which ink forcedly sent into the sub-chamber 13 by purging is returned from the communication path 21 to the main chamber 11 so that the liquid levels of the main chamber 11 and the sub-chamber 13 are at the same level.
As described above, due to the movement of the head 1, the press-contact valves 28 and 27 in the sub-chamber 13 close the sub-chamber inlet 22b and the sub-chamber outlet 21b.
open. Since the pressure contact valve 27 is mechanically opened, quick leveling is performed.

After the leveling is performed in this manner, the second purging is performed by the above-described procedure. Then, when the second purging is completed, a command is output to a drive circuit described later to drive the carriage motor 110 and move the head 1 to a predetermined home position.

With the above control, the ink tank 10 and the front panel 30 are maintained at a predetermined temperature,
The hot melt ink in the ink tank 10 and the front panel 30 is also maintained at a predetermined temperature. In particular, by performing purging at an earlier timing before the temperature of the nozzle hole reaches the predetermined holding temperature, the temperature of the nozzle portion rapidly rises due to the heat of the high-temperature ink circulated by the purging. . As a result, when the printing operation is performed, the bubbles are removed and the ink in a sufficiently molten state can be used.

However, conventionally, since the head 1 is moved to the purging position at the right end of the printer main body at the same high speed as the movement to the home position, the sub chamber inlet 22b is rapidly opened, and the return path 3
In some cases, a negative pressure is generated in the nozzle head 7, and a film-like residual ink called a so-called meniscus formed in the ink ejection holes of the nozzle head 31 is broken, and the outside air is sucked into the nozzle head 31 in some cases. As a result, there has been a problem that ink is not discharged even when the piezoelectric element is changed.

Therefore, in this embodiment, when the head 1 is moved to the purging position, the head 1 is moved from the normal moving speed of 25.6 ips (inch per second) to 0.5.
It was configured to decelerate to a speed less than or equal to ips.

Hereinafter, the movement control of the head 1 in this embodiment will be described in detail with reference to FIGS.

More specifically, the drive control circuit of the carriage motor 110 is configured as shown in FIG. Control device 9
0 denotes a CPU 91a for performing various operations and a printer 100
ROM 91b and RAM 91c for storing programs and parameters necessary for controlling the
0 and an interface 9 for exchanging data necessary for recording between a personal computer (not shown)
2, a driving circuit 132 for driving the carriage motor 110 and the transport motor 106 based on a control signal from the CPU 91a, the heater 17 and the front panel heater 3.
3 based on a control signal from the CPU 91a.

The heater and motor control in the controller 90 will be described with reference to the flowchart of FIG.

First, the head 1 is moved to the carriage motor 110.
To move to the high-speed heating position (S1, S
Indicates a step. Hereinafter the same). The high-speed heating position is a position on the end side in the arrow X1 direction shown in FIG. 1, and power is supplied to the AC heater at this position. When moving to the high-speed heating position, the moving speed of the carriage motor 110 is set to a high speed as in the printing operation.

In this high-speed heating position, by operating the heater control circuit 133, the AC heater 17a of the ink tank 10 and the AC heater constituting the front panel heater 33 of the front panel 30 are operated (S2). 10 and the front panel 30 are rapidly heated to a predetermined temperature.

Then, by a temperature detection circuit (not shown),
The temperatures of the ink tank 10 and the front panel 30 are detected, and when the detected temperature reaches a predetermined temperature, for example, about 150 ° C. (S3; YES), the heater control circuit 133 is controlled to stop the operation of the heater and , CPU 91a
Output a control signal to the drive circuit 132 to reduce the moving speed of the head 1, in the present embodiment, to 0.1.
Switch to 5 ips (S4).

Next, by outputting a control signal to the drive circuit 132, the carriage motor 110 is driven to move the head 1 to the purging position (S
5). The purging position is on the end side in the X2 direction shown in FIG. 1 with the movement of the head 1, and the cam 50 and the frame 54 come into contact with each other.

However, the moving speed at this time is 0.5 ip
s, the contact surface 50b of the cam 50
Abuts on the frame 54 (see FIG. 5) of the printer body, the cam surface 50b slowly pushes the upper end 24a of the valve opening / closing lever 24 downward in FIG.
4 is slowly swung about the lever base 25 as a fulcrum.

As described above, the speed at which the contact surface 50a of the cam 50 contacts the frame 54 is low, and the valve opening / closing lever 24 swings while pressing the pressure contact valve 28 and the sub chamber inlet 22.
b, the pressure contact valve 28 and the auxiliary chamber inlet port 22 are released.
A gap is gradually formed between the return path b and the negative pressure, and the negative pressure generated in the return path 37 is very small. As a result, the meniscus formed in the nozzle hole is not broken, and the outside air is not drawn.

When the swing of the valve opening / closing lever 24 advances, the pressure contact valve 27 and the sub chamber outlet 21b are pressed against each other, the sub chamber inlet 22b is opened, and the sub chamber outlet 21b is closed. Then, the purging process described above is performed (S6).

Next, the moving speed of the head 1 is switched to the same high speed as in a normal printing operation (S7), and a command is output to the carriage driving circuit 132 to output the carriage motor 11
0 is driven to move the head 1 to the home position (S8).

As described above, according to the present embodiment, during the purging process, the moving speed of the head 1 is reduced, so that outside air is not sucked into the nozzle head 30 and good ink ejection after the purging process is performed. Actions can be taken.

In addition to the purging process, since the head 1 is moved at a normal high speed, the printing operation can be performed quickly.

In this embodiment, the reason why the moving speed of the head 1 during the purging process is set to 0.5 ips or less is a result of trials at various speeds in the experiment. In other words, the present invention does not limit the moving speed of the head 1 during the purging process to this moving speed, and when the sizes of the ink storage chambers of the nozzle head 31 are different, the conditions such as the size of the respective ink storage chambers are different. May be set to an appropriate value that does not destroy the meniscus.

Further, in this embodiment, the timing for starting the deceleration is the same as the timing for starting the purging process. However, the present invention is not limited to this.
The deceleration may be started at an appropriate timing before the contact surface 50a and the frame 54 start contact.
In this way, the time required for the entire purging process can be reduced.

[0070]

According to the hot melt ink jet printer according to the first aspect, when the cam means moves the valve means to the open position of the ink return hole, at least at the start of contact between the cam means and the contact member, Since the deceleration means for reducing the moving speed of the carriage is provided, it is possible to prevent the ink return hole from being suddenly opened, and to suppress the negative pressure generated in the return path to a low level. as a result,
Since the meniscus formed in the ink ejection hole of the nozzle head is prevented from being destroyed and the outside air is not sucked into the nozzle head, it is possible to perform excellent ink ejection.

According to the hot melt ink jet printer according to the second aspect, the ink return hole can be opened and closed gradually by rotating the valve means. Negative pressure can be reduced. As a result, it is possible to prevent the meniscus formed in the ink ejection holes of the nozzle head from being destroyed, and to prevent the outside air from being sucked into the nozzle head.

According to the hot melt ink jet printer of the third aspect, when the cam means moves the valve means to the open position of the ink return hole, the moving speed is reduced when the ink return hole is in the open state. By doing so, the negative pressure generated in the return path is controlled so as not to destroy the meniscus due to the ink formed in the ink discharge port of the nozzle head, so that the suction of outside air from the ink discharge port is prevented. And good ink ejection can be performed.

According to the hot melt ink jet printer described in claim 4, when the cam means moves the valve means to the open position of the ink return hole,
Instead of being decelerated to a predetermined speed in all periods, the deceleration by the deceleration means is started from a predetermined timing before the contact between the cam means and the contact member is performed. The carriage can be moved at a normal moving speed up to, and the time required for the return processing can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of a hot melt inkjet printer according to an embodiment of the present invention.

FIG. 2 is a three-dimensional exploded view of a head 1 in the printer of FIG.

FIG. 3 is a top view showing an upper surface of an ink tank 10 in the head 1 of FIG.

4 shows an ink tank 10 of the head 1 of FIG. 2,
4A is a rear view, and FIG. 4B is an end view showing an AA end face in FIG.

FIG. 5 is a rear view showing the rear surface of the front panel 30 of the head 1 of FIG. 2;

FIG. 6 is a plan view of an ink tank 10 of the head 1 of FIG.

7 shows an ink tank 10 of the head 1 of FIG. 2,
(A) is an end view showing the BB end face in FIG. 6, (b) is a C-
It is an end elevation which shows C end surface.

8 is an explanatory diagram of the vicinity of a valve opening / closing lever 24 and a nozzle 32 in the head 1 of FIG.

9 is a plan view showing the state of the cam 50 and the leaf spring 60 when the head 1 of FIG. 2 reaches the purging position.

FIG. 10 is a plan view showing a state of a cam 50 before the head 1 of FIG. 2 reaches a purging position.

FIG. 11 is a block diagram illustrating a schematic configuration of a carriage motor drive control circuit according to an embodiment of the present invention.

12 is a flowchart showing a control process of the head 1 in the drive control circuit of FIG.

FIG. 13 is an explanatory diagram of a conventional head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Head 10 ... Ink tank 11 ... Main chamber 13 ... Sub chamber 17 ... Ink tank heater 17a ... AC heater 17b ... DC heater 19 ... Ink tank lid 21 ... Communication passage 21a ... Main chamber inlet 21b ... Sub chamber outlet 22a ... Main chamber outlet 22b ... Sub chamber inlet 24 ... Valve opening / closing lever 25 ... Lever base 29 ... Filter 30 Front panel 31 Nozzle head 33 Front panel heater 35 Outbound path 35a Outbound entrance 35b Outbound path 37 Return path 37a Return path 37b ··· Incoming path entrance 38 ··· Piezoelectric transducer 40 ··· Melting tank 50 ··· Cam 50 ··· Cam 50a ··· Abutment surface 50b ··· Cam surface 70 ··· Control substrate stage 91a. · CPU 100 ... printer 107 ... carriage 110 ... carriage motor 132 ... drive circuit

Claims (4)

[Claims] 1. A hot melt ink heated and melted on a recording medium while moving a head body in a printer frame in a horizontal direction perpendicular to a recording medium discharge direction along a recording medium discharge direction. A hot melt inkjet printer that performs printing by discharging, a carriage that supports the head body so as to be able to reciprocate in the lateral direction, a main chamber and a sub chamber that store hot melt ink that has been heated and melted, and the main chamber. A communication passage connecting the chamber and the sub-chamber,
An ink tank supported by the carriage; a nozzle head attached to the ink tank via a support member to discharge the hot melt ink onto a recording medium; and a supply of the hot melt ink from the main chamber to the nozzle head. A forward path for performing processing, a return path for performing a return process of the hot melt ink from the nozzle head to the sub chamber, an ink return hole connecting the sub chamber and the return path, and the sub chamber and Valve means for opening and closing an ink supply hole connecting the communication path; cam means for engaging the valve means to move the valve means to an open position or a closed position of the ink return hole or the ink supply hole; When the carriage is moved to the return processing position,
An abutting member on the printer frame side that contacts the cam means and moves the valve means to the open position of the ink return hole by the cam means; and an open position of the ink return hole of the valve means by the cam means. A hot-melt inkjet printer, comprising: a speed-reducing means for reducing the moving speed of the carriage at least at the time of starting contact between the cam means and the contact member at the time of movement to the position. 2. The hot melt inkjet printer according to claim 1, wherein the valve means has a mechanism for opening and closing the ink return hole by turning. 3. The moving speed at the time of deceleration is such that a negative pressure generated in the return path by opening the ink return hole is used to destroy a meniscus due to ink formed at an ink discharge port of the nozzle head. The hot melt inkjet printer according to claim 1, wherein the speed is set to a value that does not cause a problem. 4. The apparatus according to claim 1, wherein the deceleration unit starts the deceleration at a predetermined timing before the cam unit comes into contact with the contact member. Hot melt inkjet printer.