JP2001030518A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ejected liquid from adhering to the nozzle of a recording head when the nozzle is cleaned by ejecting ink or cleaning liquid from the nozzle to the exhaust opening of a liquid exhaust container by preventing liquid dropped into the liquid exhaust container from flowing out again through the exhaust opening. SOLUTION: When the nozzle 52a of a recording head 52 is cleaned internally, the recording head 52 is moved directly above the exhaust opening of a liquid container 106 disposed on the outside of a writing range and ink or cleaning liquid is ejected from the nozzle of the recording head 52. A pair of guide plates 14, 16 having tapered faces 14a, 16a are provided on the upper wall 12 of the liquid container 106 while projecting downward such that the facing parts of the guide plates 14, 16 define the exhaust opening. Fluid guide faces 14b, 16b are provided, while inclining substantially in parallel with the tapered faces 14a, 16a, at an upper part in the liquid container 106 in order to guide the flow of fluid downward.

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, and more particularly to an ink jet printer which discharges ink or a cleaning liquid from nozzles of a recording head to clean an ink passage.

[0002]

2. Description of the Related Art In Japanese Patent Application Laid-Open No. 8-112916, a venturi passage (6) is provided above a reservoir (4) as shown in FIG. An ink jet printer is disclosed wherein ink droplets enter the venturi passage (6). The Venturi passage (6) increases the velocity of the ink-containing air flow and reduces the static pressure according to Bernoulli's principle as the flow of air around the ink droplet flows toward the reservoir (4). This creates a pressure gradient in the passage, which causes the air containing the droplet stream to flow in the direction of the flow and in the direction of the reservoir. This inflow prevents mist-like fluid containing misguided ink droplets called mist from adhering to the bottom surface of the recording head (8). If the mist adheres to the bottom surface of the recording head (8), an error occurs in the trajectory of the ink droplet at the time of image formation, and the image quality deteriorates.

[0003]

SUMMARY OF THE INVENTION The above conventional reservoir
When a large number of gaseous ink droplets accumulate below the venturi passage (6), the flow of the gas moves upward through the venturi passage (6), and the ink droplets ejected from the recording head (8). Fig. 4
As shown by the reference numeral 10, the print head exits upward from the opening of the venturi passage (6) and adheres to the bottom surface of the recording head (8) as mist. In addition, reservoir (4)
There is a problem that gaseous ink droplets flow out of a gap between the lower end of the venturi passage (6) and adhere to other portions of the printer. An object of the present invention is to solve the above problems.

[0004]

In order to achieve the above object, according to the present invention, a recording head (52) is moved to a position immediately above a discharge port (110) of a liquid container (106) provided outside a printing range. Ink or cleaning liquid is ejected from the nozzles of the recording head (52) to the discharge port (110) to discharge the recording head (5).
(2) In the ink jet printer which prevents clogging of the ink passage of (2), the liquid container (106)
The tapered surface (14) is formed on the upper wall (12) so as to protrude inward from the upper wall (12) so that the distance between the opposing walls decreases downward.
a) A pair of guide plates (14) (1) having (16a)
6), and a fluid guide surface (14) inclined above the inside of the liquid discharge container (106) substantially parallel to the tapered surfaces (14a) (16a) to guide the flow of the fluid downward.
b) (16b) is provided.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 3, (22)
Are legs (the other is not shown) disposed on the left and right of the substrate (26) of the ink jet printer (24), and the substrate (26) is fixed to the upper ends thereof. The legs (2
2) and the substrate (26) are an inkjet printer (2).
4).

A shaft holder (2) is provided on the upper part of the leg (22).
8) is fixed, and the shaft of the roll paper holder (32) is rotatably and detachably supported on the shaft holder (28). A roll portion (30a) of an image forming medium (30) wound in a roll shape is detachably held by the roll paper holder (32).

A platen (34) is provided on the substrate (26).
(Paper guide plate) is fixed, and near the upstream end of the platen (34), a guide roller (36) extending in the Y-axis direction and having substantially the same length as the width of the drawing medium (30) is arranged. .
The guide roller (36) is disposed above the roll portion (30a) of the roll paper (30), and both ends of the guide roller (36) are rotatably supported on the substrate (26) via a bracket. ing. (38) is a Y-axis rail, which is disposed horizontally above the platen (34),
Both ends are supported on the board (26) via brackets.

A Y-cursor (40) (carriage) is movably mounted on the Y-axis rail (38), and the Y-cursor (40) is a steel belt (42) endlessly stretched between pulleys. Through a Y-axis driving device (not shown) disposed on the substrate (26). A slit is formed in the platen (34) along the Y-axis direction, and a driving roller (44) is disposed in the slit.

Both ends of the driving roller (44) are rotatably supported on a substrate (26) via a bracket, and the driving roller (44) is connected to an X-axis driving device (shown in FIG. 1) provided on the substrate (26). (Omitted). The Y-axis rail (3
8), a pinch roller shaft (46) is attached to the pinch roller shaft (46) so as to be able to move up and down via an elastic mechanism (not shown), and is rotatably fitted to the pinch roller shaft (46).
8) is configured to be able to set one of a state of being separated from the surface of the drive roller (44) and a state of being in elastic contact with the surface horizontally.

A head base (50) is fixed to one side of the Y cursor (40), and four heads for four colors are provided on the head base (50).
Ink jet recording heads (52) each having a nozzle (52a) are attached. The bottoms of the four rows of recording heads (52) arranged on the same plane are elongated rectangles, and nozzles (52a) having a large number of ink ejection holes opened in a row protrude slightly from the bottoms. It is arranged.

Each of the four rows of recording heads (52) is arranged in parallel with each other at a predetermined distance from each other, and has a bottom surface with respect to an X-axis perpendicular to the Y-axis rail (38). Are arranged with a certain angle α. On the other side of the Y cursor (40), the same number of sub-tanks (54) for solvent ink of four colors (black K, cyan C, magenta M, and yellow Y) as the number of recording heads (52) are attached. The top lid of the sub-tank (54) has 3
One-way solenoid valve (56) is attached.

Each sub-tank (54) is provided with a sensor for detecting the ink level. The liquid supply surface of the sub-tank (54) corresponds to the recording head (52) such that the ink supply path, that is, the tube (53) between the recording head (52) and the corresponding sub-tank (54) is maintained at a negative pressure. 52) is disposed below the ink discharge port.

Reference numeral (58) denotes a main tank case provided on the substrate (26). The same number of main tanks (60) for four-color solvent ink as the sub-tanks (54) are provided (three are not shown). And a cleaning liquid tank (62) are detachably stored. Each tank (60) (62) is supported by a spring and sensors (136) (138) consisting of limit switches located below each tank (60) (62).
(See FIG. 3) so that the remaining amount of ink is detected.

The main tank (60) and the sub tank (54) are connected via a solenoid valve to a tube cable (12).
It communicates by 2). Reference numeral (64) denotes a supply control box attached to the substrate (26), and the pump (66) and the solenoid valves (68) (70) (72) shown in FIG.
(74) (76) (78) (80) (82) (84)
(86) (88) (90) (92) (94) (96)
(98), (100), and (101) are built in, and an electronic control circuit for controlling these electronic devices is further provided.

A controller (not shown) for controlling the XY-axis driving device and the recording head (52) is attached to the substrate (26) of the printer (24).
Reference numeral (2) denotes a wiping device for cleaning the periphery of the nozzle on the bottom surface of the recording head (52) and the discharge port of the nozzle (52a), and is configured to be driven by the wiper motor (102) (see FIG. 3). ing.

(106) is a rubber cap (10) for covering the discharge port of the nozzle (52a) of the recording head (52).
8) and a liquid discharge port (110) alternately disposed on the side of the substrate (26) outside the drawing range and in the movement range of the recording head (52), and provided with a motor (112). ) (See FIG. 4) so as to be able to move up and down.

Each cap (1) of the liquid discharge container (106)
08) and the outlet (110) are connected to a collecting pipe (120) fixed to the substrate (26) via a tube and a solenoid valve. The upper wall (1) of the liquid discharge container (106)
In 2), guide plates (14) and (16) are bent in an inverted C shape. A liquid outlet (110) is formed between the guide plates (14) and (16), and the wide opening (18) at the upper portion and the narrow opening (20) at the lower portion of the liquid outlet (110).
The tapered surfaces (14a) (16a) on the upper surfaces of the guide plates (14) and (16) are arranged between them.

On the lower surfaces of the guide plates (14) and (16), there are formed fluid guide surfaces (14b) and (16b) which are inclined in an inverted C shape. Slight gaps (65) and (67) are formed between the upper wall (12) and the side wall of the container (106). (114) is a stirring motor for stirring the ink in the main tank (60), and (116) is a leg (2).
The waste liquid tank case attached to 2), (118) is a waste liquid tank.

The waste liquid tank (118) includes a case (1).
16) supported by a spring stored in the tank (11).
The ink amount is detected by a sensor (134) (see FIG. 3) composed of a limit switch disposed between the bottom of 8) and the upper surface of the case (116).

At the bottom of each main tank (60),
A rotor made of a magnetic material is rotatably supported on a shaft, and the rotor is rotated by driving a motor (114) so that the ink in each main tank (60) is agitated. Each of the above components and devices is connected by a tube as shown in FIG. The recording head (52)
Is moved out of the drawing range by the movement of the Y cursor (40) along the Y-axis rail (38).
It is configured to be able to move to just above 12).

Next, the operation of this embodiment will be described.
To set the drawing medium (30) on the platen (34), the pinch roller (48) is raised, and the roll (30) is set.
The drawing medium (30) is pulled out from a), inserted between the driving roller (44) and the pinch roller (48) via the guide roller (36), and then the pinch roller (48) is lowered, The pinch roller (48) is brought into elastic contact with the drive roller (44) from above the image forming medium (30).

Thus, the setting of the drawing medium is completed. When the setting of the drawing medium is completed and the printer enters the drawing mode, the controller performs an ink filling operation,
Thereafter, the operation proceeds to the drawing operation. When the drawing is started, the drawing portion of the drawing medium (30) is driven by the driving roller (4).
4) Due to the intermittent rotation in one direction, the sheet is conveyed on the platen (34) in the X-axis direction, that is, the arrow direction (C).

The recording head (52) is driven based on the image information under the control of the controller, and the nozzle (5) is driven.
2a), ink is ejected from the Y cursor (4
0) by reciprocating along the Y-axis rail (38),
The drawing medium (30) is scanned along the Y axis, and the image information developed in the memory of the controller is visualized on the drawing medium (30).

When the piezo element of the recording head (52) discharges ink, the piezo element automatically sucks the ink from the sub tank (54) accordingly. In this case, unless the sub tank (54) is set to a negative pressure, the recording head (52)
Means that ink is sucked too much and the ink flows out. In order to make the sub-tank (52) have a negative pressure, in the present embodiment, the level of the bottom surface of the sub-tank (54) is set lower than the ink ejection port of the recording head (52).

When the drawing operation is completed, the sub tank (5
In 4), it is determined based on the signal of the sensor whether or not there is ink, and when it is determined that there is no ink, the operation shifts to an ink supply operation. After ink replenishment, or when it is determined that there is ink, it is determined whether or not a predetermined time has elapsed since printing, and if affirmative, the process proceeds to the cleaning operation. After the cleaning or when the predetermined time has not elapsed after printing, it is determined whether or not the predetermined time has elapsed in the drawing end or in the standby state, and if the determination is negative, the process returns to the drawing operation. If the determination is affirmative, the operation sequentially proceeds to the ink recovery operation and the head cleaning operation.

Next, the head cleaning operation will be described. First, it is determined whether there is a remaining amount in the cleaning liquid tank (62) based on a signal from the sensor (138).
An error message is displayed by indicating that there is no remaining cleaning liquid tank on the display. If it is determined that there is a remaining amount, the recording head (5
2) is moved to just above the discharge port (110) of the liquid discharge container (106). Next, the pump solenoid valves (68) and (70) are switched to the pressure feeding direction.

Next, in the head cleaning operation, the cleaning liquid tank (62) is pressurized with air for 60 seconds so that the pressure of the cleaning liquid is instantaneously sent. In this pressurizing operation, with the solenoid valve (78) closed, the pump-main tank solenoid valves (72), (74) and (76) are switched to the cleaning liquid tank direction, the pump (66) is driven, and the cleaning liquid tank is driven. (62) is carried out by sending air.

Next, the controller switches the head air solenoid valves (74) and (88) to the air feeding direction, switches the head solenoid valve (56) to the air feeding direction, drives the pump (66), and drives the recording head (52). ) Is supplied with air for 20 seconds. Thereby, the three-way solenoid valve (56)
Ink from the nozzle to the recording head (52) is extruded by air, and is discarded from the nozzle to the discharge port (110). Next, the controller switches the electromagnetic valves (74) and (76) toward the cleaning liquid tank, switches the cleaning liquid tank electromagnetic valves (78) and (88) and the head electromagnetic valve (56) toward the cleaning liquid tank, and drives the pump (66). The cleaning liquid is pumped to the recording head (52) for 20 seconds.

Thus, the cleaning liquid is discharged from the nozzle (52a) to the discharge port (110), and the inside of the recording head (52) is washed with the cleaning liquid. Next, the controller pumps air to the recording head (52) for 30 seconds. Next, the controller moves the recording head (52) right above the wiping device (2) to perform wiping of the bottom of the recording head (52), that is, wiping operation. Next, the controller pumps the cleaning liquid to the recording head (52) for 20 seconds,
The cleaning liquid is discharged from a) to the discharge port (110).

Next, the controller operates the waste liquid tank (11).
8) Apply a negative pressure for 5 seconds to collect the liquid accumulated in the collecting pipe (120). Next, the controller operates the cleaning liquid tank (6).
2) is released to the atmosphere, and the pressurization of the cleaning liquid tank (62) is released. In the case of performing the idle discharge of the ink, the controller drives the ink control unit of the recording head (52), discharges the ink from the nozzle (52a) on the liquid discharge port (110), and removes the clogging of the nozzle (52a). prevent.

The nozzle (52a) of the recording head (52) is located just above the discharge port (110) of the liquid discharge container (106).
When a liquid such as ink or cleaning liquid is ejected, the liquid
In the middle, it falls into the container (106) from the liquid discharge port (110) as shown by the arrow a. The liquid that has fallen into the container (106) becomes a mist and accumulates at the bottom of the container (106), and then flows back upward. This back-flowing fluid is indicated by arrow b
As shown by, after hitting the upper wall (12), it is guided by the fluid guide surfaces (14b) (16b) and again the container (1).
06) to the bottom and circulate in the vessel (106).

The fluid circulating by the action of the fluid guiding surfaces (14b) (16b) guides the fluid upward from the bottom of the container (106) in a direction deviating from the outlet (110). It does not go outside from (110). When the pressure in the liquid discharge container (106) increases with the gaseous fluid, the fluid is discharged to the outside through the gaps (65) and (67). Thereby, the liquid discharge container (10
6) Prevents the internal pressure from increasing.

[0033]

Since the present invention is constructed as described above, when cleaning the ink passage of the recording head, liquid such as idle ink or cleaning liquid ejected from the nozzle bounces from the liquid discharge container, and the liquid containing ink is discharged. It is possible to prevent mist from adhering to the nozzles of the recording head.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the present invention.

FIG. 2 is an external view of an inkjet printer.

FIG. 3 is an explanatory diagram of piping showing an ink supply system of the inkjet printer.

FIG. 4 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 Reference Signs List 2 Wiping device 4 Reservoir 6 Venturi passage 8 Recording head 10 Fluid 12 Upper wall 14 Guide plate 16 Guide plate 18 Wide opening 20 Narrow opening 22 Leg 24 Inkjet printer 26 Substrate 28 Axis holder 30 Image forming medium 30a Roll section 32 Roll Paper holder 34 Platen 36 Guide roller 38 Y-axis rail 40 Y cursor 42 Steel belt 44 Drive roller 46 Pinch roller shaft 48 Pinch roller 50 Head base 52 Ink jet recording head 52a Nozzle 53 Tube 54 Sub tank 56 Solenoid valve 58 Main tank case 60 Main tank 62 Cleaning liquid tank 64 Supply controller 65 Clearance 66 Solenoid valve 67 Clearance 68 Solenoid valve 70 Solenoid valve 72 Solenoid valve 74 Solenoid valve 76 Solenoid valve 78 Solenoid valve 80 Solenoid valve 2 solenoid valve 84 solenoid valve 86 solenoid valve 88 solenoid valve 90 solenoid valve 92 solenoid valve 94 solenoid valve 96 solenoid valve 98 solenoid valve 100 solenoid valve 101 solenoid valve 102 wiper motor 106 liquid discharge container 108 cap 110 liquid discharge port 112 motor 114 motor 116 Waste liquid tank case 118 Waste liquid tank 120 Collecting pipe 122 Tube cable 134 Sensor 136 Sensor 138 Sensor

Claims (1)

[Claims] 1. A recording head (52) is moved to a position immediately above a discharge port (110) of a liquid container (106) disposed outside an image forming range, and ink or a cleaning liquid is discharged from a nozzle of the recording head (52). The recording head (5)
(2) In the ink jet printer which prevents clogging of the ink passage of (2), the liquid container (106)
The tapered surface (14) is formed on the upper wall (12) so as to protrude inward from the upper wall (12) so that the distance between the opposing walls decreases downward.
a) A pair of guide plates (14) (1) having (16a)
6), and a fluid guide surface (14) inclined above the inside of the liquid discharge container (106) substantially parallel to the tapered surfaces (14a) (16a) to guide the flow of the fluid downward.
b) An ink jet printer provided with (16b).