JPS6357238A - Ink jet printer - Google Patents

Abstract

PURPOSE:To prevent the intrusion of air and the vaporization of ink in an ink supply system by providing an ink residue sensor to detect ink consumption in the ink supply system, a device to open or close the path branched from the ink supply system, and a flexible part displacing with pressure changes in the ink supply system. CONSTITUTION:When continuous recording is made when the ink amount in an ink tank 7 reduces, negative pressure in the whole of ink supply system is increased, and a flexible film 203 in an ink residue sensor 6 lowers when a three-way valve 600 is opened and an electrode 204 and an electrode 205 come into contact with each other at the time when a given negative pressure value appears. A signal is sent to controller and the operator is notified of the fact that ink amount in the tank 7 reduces by means of sound or light. The given negative pressure value is determined the stiffness of the flexible film 203, the spring constant of a spring 206, and the interval between the electrodes. A valve 700 provided for the opened part 11 to the open air is closed when the residue of in is detected and opened in the other cases by signals from the controller. The variations in pressures in the sensor 6 with change of temperature can thus be climinated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet printer, and is an improved ink remaining amount detection device for detecting the amount of ink remaining in an ink co-supply source such as an ink storage container in 4.1f. It is.

[Prior Art] Conventional ink remaining amount detection devices for inkjet printers include an ink storage container (ink tank) as an ink supply source fixed to the main body of the inkjet printer, or an inkjet in which a recording head is mounted on a carriage. Some printers are equipped with a spare ink tank mounted on a carriage. In such a conventional ink remaining amount detection device, a reed switch is used to detect a float built in Ii7.2 stones that moves according to changes in the ink liquid level, or a light emitting means J5 and a light receiving means are provided to detect the ink liquid. A mechanism or the like is used that detects the remaining ink by utilizing the fact that the light from the light emitting means reaches the light receiving means without being blocked by the ink once the surface becomes below a predetermined value.

[Problems to be Solved by the Invention] However, the conventional ink remaining amount detection device for an inkjet printer has problems, especially when it is installed in a fixed ink tank and the ink tank is formed of a flat and flexible bag. Since the rate of change in the liquid level due to the decrease in the remaining amount of ink was small, accurate and reliable detection could not be performed.

Further, such a remaining ink amount detection device has to be replaced at the same time as the ink tank is replaced, which results in an increase in the price of the ink tank itself.

On the other hand, when the remaining ink level detection device is installed in a spare ink tank mounted on the carriage, the remaining ink level can be detected because the liquid level in the spare ink tank shakes when the carriage moves in a predetermined direction. Malfunctions may occur in the apparatus, and in addition, the electrical connection means necessary for the remaining ink amount detection apparatus also moves with the carriage, posing a problem in the reliability of the connection part.

Therefore, a residual ink detection device has been proposed that is provided in an ink supply path between a recording head and an ink tank.

FIG. 5 shows a conventional ink remaining amount detecting device of the type that is open to the atmosphere.
Reference numeral 0 designates an air-open manometer disposed midway through the path of the ink supply system, and reference numerals 200a and 200b designate ink presence/absence detection units such as a pair of electrodes, which detect a drop in the ink liquid level I.

Further, FIG. 6 shows a conventional closed-type ink remaining amount detection device, in which 301 is a flexible membrane (diaphragm) constituting a part of the ink supply path, and 300 is a diaphragm 30.
The electrode 302 is connected to the electrode 30 in response to the downward displacement of the diaphragm in the diagram as the negative pressure increases in the ink supply system.
Fixed electrode in contact with 0, 303 is diaphragm 301
is a spring member that moves upward in the figure. In addition, as this closed-type detection device, there is also one in which a pair of fixed optical sensors are provided, a light shielding plate is provided on the diaphragm so that the optical path can be blocked, and the displacement thereof is detected.

However, in an inkjet printer having an apparatus that is open to the atmosphere, it is necessary to dispose the ink tank above the ink presence/absence detection means 200a and 200b, and therefore the height of the entire printer must be increased.
As a result, there was a problem in that the printer became larger.

Another problem is that when a decrease in ink is detected and the ink tank is replaced with a new one, it takes a very long time to recover the liquid level I in the manometer 200.

In addition, in inkjet printers that have a closed-type ink remaining amount detection device, a diaphragm placed in a part of the ink supply system has a diaphragm of several tens of mI, which can cause deterioration in printing quality.
I+1I2(t) Because it is required to be displaced with good response under the ultra-micro pressure, it is desirable to be made of a material such as extremely flexible and low hardness rubber, and furthermore, the thickness should be reduced to 0.
．． It is desirable that the thickness be about 1 mm to 0.3 mm.

Therefore, there is a problem in that ink in the ink supply system evaporates or air enters the ink supply system through the diaphragm 301, which may cause ink to fail to be ejected. Furthermore, when printing quality deteriorates, a recovery operation is generally performed by applying a large amount of pressure to the ink in the head, but this pressure is also applied to the tire flam via the ink supply pipe, so there is no residual ink. There was also a risk that the amount detection device would be destroyed.

[Means for Solving the Problems] The invention solves these conventional problems, has high reliability in detecting the remaining amount of ink, and detects evaporation of ink in the ink supply system through the remaining ink amount detection device. The purpose of the present invention is to provide a stable inkjet printer that prevents air from entering the system and does not cause ejection failure.

Another object of the present invention is to provide an Infusiera 1 to printer in which the remaining ink amount detection device is reliably protected from the large pressure generated during head ejection recovery processing and the like.

Therefore, in the invention, a branch path branched from an ink supply system from an ink supply source, an opening/closing means that can open and close the branch path, and a means that is connected to the branch path and can be displaced according to pressure changes in the ink supply system. The present invention is characterized in that it has a flexible ff1 member, and further includes ink remaining amount detection means that detects the displacement of the flexible ff1 member to detect ink consumption in the ink supply source.

[Sakukawa] In other words, according to the invention, if the opening and closing of the branch path by the opening/closing means is appropriately controlled and it is closed, for example, except when detecting the remaining amount of ink, the air that has passed through the flexible membrane will be able to absorb the ink. It will not enter the supply system. Furthermore, evaporation of ink within the ink supply edge path can also be prevented. Furthermore, if the opening/closing means is kept closed even when performing ejection recovery processing for the head, for example, the remaining ink amount detecting means will not be destroyed.

[Example] Hereinafter, the tree invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the configuration of the main parts of an inkjet printer according to the present invention. Here, 1 is a recording head for ejecting liquid droplets onto a recording medium whose recording surface is regulated by a platen 8;
A carriage 2 is mounted with the recording head 1 and is movable along a kite G extending in the axial direction of the platen 8. 4
is a spare ink tank mounted on the carriage 2 to prevent air mixed in the supply path from reaching the recording head 1 and to absorb the influence of inertia of ink due to scanning of the carriage 2. Reference numeral 3 denotes a supply pipe for supplying ink in the preliminary ink tank 4 to the recording head 1.

Reference numeral 5 denotes a supply pipe 58 for supplying ink into the preliminary ink tank 4, and a suction means (not shown), which is used to suck air and ink from the preliminary ink tank 4 and maintain the liquid level inside. It is a flexible communication member that brings together the suction tubes 5B and protects them.

Reference numeral 7 denotes an ink tank as an ink supply source, and the figure shows a bag-shaped sealed ink tank made of plastic, old aluminum, or the like and made flat and flexible. 600 is a three-way valve, which is connected to the remaining ink amount detection device 6 via the branch path 10 of the supply system. Further, the remaining ink amount detection device 6 is connected to the dog air release section 11 having a valve 700. These three-way valve 600, valve 700
The remaining ink amount detection device 6 is coupled to a control section which will be described later with reference to FIG.

Reference numeral 9 denotes a cap member that faces the recording head 1 outside the recording range of the recording head 1, for example at the home position, and can be joined/separated by moving in the C direction relative to the recording head 1, when not recording or during transportation. At this point, it is joined to the recording head 1 to protect it and prevent it from drying out. Further, for example, a suction means such as a pump may be coupled to the cap member 9 to perform a suction process when the cap member 9 is connected to the recording head 1, thereby performing ejection recovery process and the like.

In this configuration, ink stored in the ink tank 7 is guided to the reserve ink tank 4 mounted on the carriage 2 via the three-way valve 600 and the supply pipe 58. Further, the ink is guided from the reserve ink tank 4 through the supply pipe 3 to the recording head 1 mounted on the carriage 2, and is ejected by the recording head I onto the recording medium on the °C platen 8 to perform recording.

FIG. 2 shows an embodiment of the remaining ink amount detection device 6. As shown in FIG. Here, 201 and 202 are a main body and a cover, respectively, and they can be connected by adhesive, welding, screws, or the like. 203 is a membrane that partitions the space formed by the main body 201 and the cover 202 and is made of a flexible material such as rubber at least in part, and the space on the main body 201 side partitioned by this film 203 is completely sealed from the outside air. The main body 201 and the cover 202 are supported at the joint portion thereof so that the main body 201 and the cover 202 are connected to each other. 204 is a conductive electrode bonded to the upper part of the film 203 by adhesive or the like; 205 is the electrode 2;
This is an electrode fixed to the cover 202 at a position where it is in contact with the electrode 04.

In this configuration, when the amount of ink in the closed ink tank 7, at least a part of which is made of a flexible member, becomes small, @! When printing continues, the negative pressure of the entire ink supply system increases, as indicated by the leftward arrow in the figure. Accordingly, when the three-way valve 600 is opened in three directions, the flexible membrane 203 inside the remaining ink amount detection device 6 is also crushed and lowered, and when a predetermined negative pressure value is reached, the electrode 204 and the electrode 20
5 comes into contact. As a result, a signal indicating that the contact has been made is sent to the control section shown in the third figure, and the operator can be notified by means of sound or light, for example, that the amount of ink in the ink tank 7 has become small.

Here, it is desirable to set the predetermined negative pressure value at which the electrodes 204 and 205 come into contact before the recording quality of the inkjet printer deteriorates, and the value is determined by the rigidity of the flexible member 203 and the spring constant of the spring 206. and can be determined by the electrode spacing.

The pulp 700 provided in the atmosphere opening part 11 is closed when the remaining amount of ink is detected. In other cases, it is opened and closed by a signal from the control section shown in FIG. 3 to eliminate pressure fluctuations occurring within the ink remaining amount detection means 6 due to temperature changes and the like.

Note that, in addition to using the electrodes described above to detect the remaining amount of ink, it is also easy to use an optical sensor or the like to detect the remaining amount of ink.

FIG. 3 shows an example of the configuration of the control system of the inkjet printer according to this example. 1200 is CPII, ll0M
.

It is a control section in the form of a microcomputer having a RAM, etc., and controls each section according to the processing procedure shown in FIG. . PS is a paper sensor that detects the recording paper P, and in response to the detection, the control unit 1200 controls the paper feed mechanism 8A including a paper feed motor.
The platen roller 8 is driven via the platen roller 8 to control paper feeding.

C5 is a carriage position sensor, and in accordance with the detected position information, the control unit 1200 controls the drive of the carriage 2 and the positioning of the home positive stain 1 etc. via the carriage motor 28.

9A +1 This is a transport mechanism having a transmission mechanism such as a gear and a cam, and a drive member such as a motor for transporting the cap 9 in the direction C in FIG. Reference numerals 1205 and 1255 are a command means and a notification means provided on an operation panel (not shown), respectively, and include a key for commanding the start of recording, etc.
It also has a display or buzzer for displaying messages such as prompting replacement of the ink tank. Further, the valves 600 and 700 are opened and closed according to the processing procedure shown in FIG.

Note that the remaining amount detection signal can be a signal generated by contact between the electrodes 204 and 205 in the embodiment shown in the second figure.

Further, the ink tank detection signal may be a signal from a limit switch or the like provided near the position of the device in order to detect whether or not the ink tank 7 is attached or replaced.

FIG. 4 shows an example of a processing procedure when detecting the amount of ink remaining in the ink tank 7. First, in step S1, the valve 700 in the atmospheric release means is closed to make the inside of the ink remaining amount detection device 6 a closed system, and then in step S2, the three-way valve 600 at the branch part is made to be a three-way self-contained system, and the ink supply system internal pressure is is transmitted to the detection device 6. When a signal indicating that ink is not detected from the ink remaining amount detection device 6 is inputted manually in step S3, a warning is issued to the operator by a display or sound prompting the ink tank replacement on the notification means 1255 in step S5, and recording is made. Stop processing. Next, in step S6, the branch system direction of the three-way valve 600 is closed to make the inside of the remaining ink amount detection device 6 an isolated chamber, and then in step S8
At this point, the valve 700 is opened to communicate with the atmosphere, and the pressure inside the remaining ink amount detection device 6 is brought to zero in terms of gauge pressure.

Next, in step S8, the carriage 2 is positioned at the home position, the cap part 9 is joined to the recording head 1, and the operator waits for the ink tank to be replaced.

For example, when replacement of the ink tank 7 is detected in step S9 by a microswitch or the like disposed at the ink tank arrangement location, the process proceeds to step 10, where a command is given to restart recording to enable recording.

If an affirmative determination is made in step S3, that is, if it is detected that there is ink in the supply system due to non-contact between the electrodes 204 and 205 of the remaining ink amount detection device 6, the process advances to step S20, and the three-way valve 600 is closed. The branch direction is closed,
Next, in step 521, the atmosphere release valve 700 is opened, and then in step 522, a recording process, a standby process,
Perform other processing such as ejection recovery processing. Then, during such recording processing, the processing is interrupted, for example, every predetermined time period or every time a predetermined amount of recording is performed, and the process returns to step Sl to perform remaining amount detection processing and the like.

In the discharge recovery process, the branching direction of the three-way valve [0 is closed and the cap member 9 is joined to the head 1 in the same manner as in step s6 and step S8, and in this state, for example, the suction means connected to the cap member 9 is Alternatively, clogging of the ink ejection ports can be removed by forcibly discharging ink from the ink ejection ports of the head 1 by driving a pressurizing means disposed at an appropriate location in the supply system. Since the branch direction of the three-way valve 600 is closed, the pressure propagating to each part of the supply system at this time does not reach the inside of the remaining ink amount detection device 6, so that the diaphragm 203 is not destroyed.

In the embodiment described above, the branch direction of the three-way valve 600 is closed except when detecting the remaining amount of ink.
It is possible to prevent the air that has passed through the diaphragm constituting the remaining ink amount detection device 6 from entering the ink supply system during recording, etc., and it is also possible to prevent the ink in the ink supply system from evaporating through the diaphragm. It is now possible to prevent non-ejection caused by the arrangement of the remaining ink amount detection device.

Furthermore, by appropriately controlling the three-way valve 600,
Even if a large pressure is applied within the supply system during the ejection recovery process of the head, this does not reach the inside of the remaining ink amount detection device 6, so the diaphragm 203 can be prevented from being destroyed and its durability can be greatly improved. did it.

Further, the control of the three-way valve 600 is particularly effective in controlling the movement of the carriage 2 in an apparatus in which recording is performed in conjunction with the reciprocating movement of the carriage 2 as in the embodiment.

This is also effective in protecting the remaining ink amount detecting device 6 from pressure waves that may occur in the supply pipe due to shocks at the time of stopping. This is because on the upper side, the branching direction of the three-way valve 600 is used as a leap during recording processing.

In addition, the atmosphere venting section 11 having the valve 700 is connected to the remaining ink amount detection device 6 and is vented to the atmosphere at times other than when detecting the remaining amount of ink. It is now possible to eliminate pressure fluctuations inside the remaining ink amount detection device 6 due to air intrusion or the like.

Note that the present invention is not limited to the inkjet printer as shown in the first diagram, but is, for example, an infusier tortridge type having a so-called full multi-type recording head in which ejection orifices are aligned over the entire width of the recording medium. The ink tank may be a fixed ink tank, and the ink may be replenished by pouring or the like into the tank.

"Effects of the Invention" - As explained, according to the present invention, the reliability of ink remaining amount detection is high, and the ink in the ink supply system through the ink remaining amount detection device is not evaporated or is It is possible to realize a stable inkjet printer that prevents air from entering and does not cause ejection failure.

Furthermore, the remaining ink amount detection device can be reliably protected from the large pressure generated during head ejection recovery processing, and its reliability is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the configuration of the main parts of an inkjet printer to which the present invention can be applied, FIG. 2 is a sectional view showing an embodiment of the ink remaining amount detection device of the present invention, and FIG. FIG. 4 is a flowchart showing an example of a processing procedure according to the present invention; FIGS. 5 and 6 show two examples of conventional ink level detection devices for inkjet printers. FIG. 5A... Ink supply pipe, 6... Ink remaining amount detection device, 11... Atmospheric communication section, 201... Main body, 202... Cover, 203... Flexible membrane (diaphragm), 204.20
5... Electrode, 600... Three-way valve, 700... Valve. □□-7 Figure 1 Figure 2 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1) A branch path branching from an ink supply system from an ink supply source, an opening/closing means capable of opening and closing the branch path, and an opening/closing means connected to the branch path and capable of opening and closing the branch path according to pressure changes in the ink supply system. 1. An inkjet printer comprising: a flexible member that is movable; and residual ink amount detection means for detecting ink consumption in the ink supply source by detecting the displacement of the flexible member. 2) The inkjet printer according to claim 1, wherein the branch path is closed by the opening/closing means when the remaining amount of ink is not detected. 3) In the inkjet printer according to claim 1 or 2, the remaining ink amount detection means includes:
An inkjet printer characterized in that an atmosphere opening means is connected to the inside of the ink branching system formed by the flexible member to allow the atmosphere to be exposed. 4) In the inkjet printer according to any one of claims 1 to 3, when detecting the remaining amount of ink, the atmosphere opening means is closed so that the ink branch system is blocked from the atmosphere. An inkjet printer characterized in that the opening/closing means is opened to fluidly connect the ink branch system and the ink supply system. 5) In the inkjet printer according to any one of claims 1 to 4, the ink supply source has an ink tank in the form of a removable cartridge, and by replacing the ink tank, An inkjet printer characterized in that ink is replenished to the ink supply system.