JPS63247046A - Detector for residual amount of ink - Google Patents

Abstract

PURPOSE:To enable a stable function of detecting the residual amount of an ink to be constantly maintained, by providing a conductive member elastically deformed based on the variations in the liquid pressure of the ink, and a detecting member the electrical contact condition of which is maintained by maintaining contact with the conductive member and is interrupted by an elastic deformation of the conductive member. CONSTITUTION:When an ink is normally maintained in an ink-supplying system, a detecting member 25 consisting of a conductor is maintained in contact with an upper surface of a bellows 23, whereby an electrical contact condition between a lead wire 28A, 28B is secured through a nut 27, an adjusting screw 26, the detecting member 25 and the bellows 23. A slight negative pressure exists in the ink-supplying system communicating with an ink chamber 22. When the residual amount of the ink is reduced and the negative pressure in the ink chamber 22 reaches a predetermined value, the bellows 23 is contracted, and a contact surface thereof is separated from the detecting member 25, whereby the passage of an electric current is interrupted, and it is detected that the residual amount of the ink has reached a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a remaining ink amount detection device, and more particularly, to an ink remaining amount detection device that is disposed in an ink supply system and that detects the remaining ink amount based on changes in the pressure thereof. The present invention relates to a detection device.

[Conventional technology]

2. Description of the Related Art In recent years, inkjet printers that record images, characters, etc. on a recording medium by ejecting ink from fine nozzles have become popular. This type of printer does not use an ink ribbon, but instead supplies liquid ink stored in an ink tank to the ejection mechanism of the print head, which is connected to the ink tank via a tube, and prints it as fine droplets onto paper, etc. Recording is performed by flying the light onto a recording medium. Therefore, unlike ink ribbon type printers, inkjet printers are usually equipped with a mechanism to detect the amount of ink remaining in the ink tank in order to prevent printing defects due to running out of ink. Structures have been adopted that issue a warning sound when the ink runs out, prompting the user to refill the ink or replace the cartridge-type ink tank.

FIG. 2 shows an example of the configuration of the main parts of this type of liquid jet recording apparatus having a remaining ink amount detection means.

In FIG. 2, 1 is a recording head that discharges droplets onto a recording medium whose recording surface is regulated by a platen 2, and 3 is a recording head on which the recording head 1 is mounted, and is mounted along a guide G extending in the axial direction of the platen 2. 4 is a spare ink tank mounted on the carriage 3; 5 is a supply pipe for supplying ink in the spare ink tank 4 to the recording head 1; 6 is a flexible pipe that combines a supply pipe 6A for replenishing ink to the spare ink tank 4 and a suction pipe 6B connected to the pump 7 and used for maintaining the liquid level in the spare ink tank 4. It is a communication member.

The pump 7 is connected to the capping 8 and sucks ink from the tip of the recording head 1 in the event of printing failure or when replacing the ink tank 9. Note that 9 is an ink tank serving as an ink supply source, and in this example, a bag-shaped tank made of a flat and flexible material such as plastic or aluminum is shown. Furthermore, 10 is an ink remaining amount detection device disposed in the middle of the supply pipe 6A and communicating with the ink tank 10.

In this configuration, the ink stored in the ink tank 9 is guided to the reserve ink tank 4 mounted on the carriage 3 via the remaining ink amount detection device 10 and the supply pipe 6A. Further, the ink is guided from the reserve ink tank 4 through the supply pipe 5 to the recording head 1 mounted on the carriage 3, and is ejected by the recording head 1 onto a recording medium (not shown) on the platen 2 to perform recording.

FIG. 3 shows a conventional example of the remaining ink amount detection device 10. Here, 11 and 12 are a main body case and a cover, respectively, which are joined by adhesive, welding, screws, etc.
A and an ink outlet 11B are provided. 13 is a membrane composed of a flexible member that partitions the space formed by the main body case 11 and the cover 12, and this visible membrane 13 completely seals the partitioned space on the main body case 11 side from the outside air. It is supported at the joint between the case 11 and the cover 12 so that the case 11 and the cover 12 are connected to each other.

Reference numerals 14 and 15 denote an upper actuating plate and a lower actuating plate that are attached to sandwich the flexible membrane 13 from above and below, and the upper actuating plate is made of a conductive material. An adjustment shaft 16 having a threaded portion 16A is fixed to the cover 15 so as to pass through the upper surface of the cover 12. Reference numeral 17 represents an adjustment nut screwed onto the threaded portion 16A, and reference numeral 18 represents a spring holding member provided on the lower surface side of the nut 17 and holding the spring 19 between the nut 17 and the upper surface of the cover 12.

Moreover, 20A and 20B are electrodes attached to the lower surface side of the cover 12, and 21A and 21B are lead wire terminals provided on the upper surface side of the cover 12 and connected to the electrodes 20A and 20B, respectively. Therefore, in this example, the biasing force of the springs 19 toward the electrodes 20A and 20B of the actuating plates 14 and 15 can be adjusted by tightening the nut 17. Since the flexible membrane 13 receives the liquid pressure from the ink in the ink chamber 22 of the main body case 11 partitioned by this, the flexible membrane 13 receives both the liquid pressure of the ink and the above-mentioned biasing force of the spring 19. The actuating plate 14 is the electrode 20A, 20B.
is kept in contact with.

Therefore, when the flexible membrane 13 tries to be pulled downward due to a change in the fluid pressure in the ink chamber 22, only the biasing force of the force spring 19 resists this, and therefore, the screw tightening operation of the nut 17 is difficult. Adjustment of the operating setpoint pressure, which is sensed via the movement of the actuating plate 14.15, can be carried out. Therefore, such adjustment can eliminate changes in the operating pressure due to variations in the characteristics of the flexible membrane 13 and the spring 19.

In the configuration of the ink remaining amount device configured in this manner, when the amount of ink in the closed ink tank 9, which is at least partially made of a flexible member, becomes small, the negative voltage in the ink supply path is reduced. As the pressure increases, the flexible film 13 of the ink remaining amount detecting means moves down against the spring force when a predetermined negative pressure value set by the nut 17 is reached, and the conductive film 13 is lowered. The upper actuating plate 14 is 8i20A and 20
You can get away from B. Therefore, terminal 21A.

Since the resistance between 21B changes, it is detected that the amount of ink has become small based on this change in resistance, that is, when the switch becomes "off".

[Problem that the invention seeks to solve]

However, in the remaining ink level detection device that uses a flexible film and a spring as components as described above, the movement of the flexible film is regulated by the spring, so the conductive film attached to the flexible film is If the upper actuating plate and the electrode contact surface that maintains contact with it are not kept perpendicular to the direction of deflection of the spring, the upper actuating plate and Although both electrodes are made to be in equal contact with each other, this leads to an increase in cost, which in turn leads to an increase in the cost of the printer body in which the remaining ink amount detection device is mounted.

In addition, the force applied to the flexible membrane, that is, the actuation force of the actuation detection means, is adjusted by a nut, but the adjustment must be made in a state where no displacement occurs in the flexible membrane, and the thickness of the flexible membrane must be adjusted. Due to variations in the mounting condition when fixing the flexible membrane between the main body and the cover, etc., the operation up to the time when the operation detection means detects the remaining amount, that is, the state from when the flexible membrane starts deforming. This did not cover everything up to the adjustment of the set pressure to ensure detection.

Furthermore, since the flexible membrane is always under negative pressure from ink, the initial state of the flexible membrane changes over time due to creep, stress changes, etc. during long-term use of the printer, causing the set operating pressure to change. There was a risk that things might change.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide an inexpensive ink remaining amount detection device that always maintains a stable ink remaining amount detection function, is easy to adjust, and has little change over time. .

[Means for Solving the Problems] In order to achieve the above object, the present invention is provided in an ink supply system of a liquid jet recording device, and the remaining amount of ink in the ink supply system is controlled by changes in the liquid pressure of the ink. In the remaining ink level detection device, the ink chamber is connected to an ink supply system, and a conductive member that forms a part of the ink chamber and elastically deforms based on changes in ink pressure.
The electrical connection state is maintained by maintaining contact with the conductive member, and the electrical connection state is cut off by elastic deformation of the conductive member.The remaining amount of ink liquid is determined by the cutoff state of the detection member. is characterized in that it can be detected.

(Function) According to the present invention, when the remaining amount of ink reaches a predetermined amount, the elastically deformable bellows of the conductive member contracts due to the negative pressure of the ink liquid, and the electrical connection with the detection member is cut off. The above condition can be detected by

〔Example〕

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

FIG. 1 shows an embodiment of the invention. Here, 23 is a conductive bellows that defines the ink chamber 22 and the upper space 24, and 25 is a conductive detection member. The detection member 25 is also connected to an adjustment screw 26 made of a conductive material, and the adjustment screw 26 is screwed into a conductive nut 27 fixed to the socket portion 12A of the upper cover 12.

28A and 28B are lead wires connected to the nut 27 and bellows 23, respectively.

Thus, when ink is normally maintained in the ink supply system, the conductive sensing member 25 is kept in contact with the upper surface of the bellows 23, thereby causing the lead wire 2
An electrical connection is established from 8A to lead wire 28B via nut 27, adjustment screw 26, detection member 25 and bellows 23. Furthermore, although a weak negative pressure exists in the ink supply system communicating with the ink chamber 22, when the amount of remaining ink decreases and the negative pressure within the ink chamber 22 reaches a predetermined value, the bellows 23 contracts. As a result, when the contact surface moves away from the detection member 25, the current supply is cut off, and it is detected that the remaining amount of ink has reached a predetermined value.

Furthermore, the operating pressure at this time can be adjusted by operating the adjustment screw 26. That is, the bellows 23 is formed of an elastic member, and the spring force of the bellows mechanism varies depending on the manufacturing process and material, so initial adjustment is required. Therefore, with the adjustment screw 28,
It is also possible to adjust the initial pressing force and set operating pressure against the detection member 25 by contracting the bellows 23 to a pre-compressed state and then adjusting the tightness of the adjustment screw 26. The ink chamber 22
Since it can be easily adjusted without applying a negative pressure while being supplied to the pump, there is no need to provide a special adjustment process in manufacturing.

Furthermore, since the bellows 23 is flexible, the detection member 2
It is easily compatible with the contact surface of No. 5, so it does not require particularly high component precision or assembly precision control, and it is possible to always maintain a stable and uniform electrical contact state.

The material for the bellows 23 is preferably conductive rubber or a metal with good conductivity and elasticity. Especially when it is made of such a metal, there is almost no material creep, stress relaxation, etc., or changes over time. Therefore, continuous reproduction of good working conditions is possible.

Further, in the above example, the bellows was configured to be contracted by the negative pressure of the ink liquid, but it goes without saying that instead of this, the bellows may be configured to be stretched by the negative pressure of the ink.

〔Effect of the invention〕

As described above, according to the present invention, there is provided an ink chamber that communicates with an ink supply system, a conductive member that forms a part of the ink chamber and that elastically deforms based on changes in ink pressure, and An electrically conductive detection member is provided that maintains contact with the conductive member to obtain an electrical connection state, and detects the remaining amount of ink by breaking the electrical connection state by elastic deformation of the conductive member. Moreover, by making the detection member movable, the contact force with the conductive member can be adjusted, so that the detection pressure of the remaining amount of ink can be set without requiring high precision control. In addition, there is no need to attach an electrode specifically for detecting the conductive state, and the number of parts can be reduced, which greatly contributes to cost reduction. Furthermore, by making the bellows made of metal, it is possible to provide an ink remaining amount detection device that has little change over time, has good reproducibility of actuation force, and can continue stable ink remaining amount detection.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the configuration of a remaining ink level detecting device according to the present invention, FIG. 2 is a perspective view schematically showing an example of the configuration of a liquid jet recording device to which the present invention can be applied, and FIG. FIG. 2 is a cross-sectional view showing an example of the configuration of a conventional ink level detection device. DESCRIPTION OF SYMBOLS 11... Main body case, 12... Cover, 13... Flexible membrane, 22... Ink chamber, 23... Bellows, 24... Space, 25... Detection member, 26... - Adjustment screw, 27... Nut, 28A, 28B... Electrode. Figure 1 27 Latin Figure 2

Claims (1)

[Scope of Claims] 1) A remaining ink amount detection device that is installed in an ink supply system of a liquid jet recording apparatus and detects the remaining amount of ink in the ink supply system based on changes in the fluid pressure of the ink. In the apparatus, the apparatus includes: an ink chamber communicating with the ink supply system; a conductive member forming a part of the ink chamber and elastically deforming based on a change in fluid pressure of the ink; and maintaining contact with the conductive member. and a detection member in which the electrical connection state is maintained by and the electrical connection state is cut off by elastic deformation of the conductive member, and the remaining amount of the ink liquid is detected by the cutoff state of the detection member. An ink remaining amount detection device characterized by: 2) In the remaining ink amount detection device according to claim 1, the elastically deformable conductive member is in the form of a bellows,
An ink remaining amount detection device characterized in that the detection member is isolated from the ink chamber by the bellows. 3) The remaining ink amount detecting device according to claim 2, wherein the bellows is made of metal. 4) The remaining ink amount detecting device according to claim 2, wherein the bellows is made of conductive rubber. 5) In the ink remaining amount detection device according to any one of claims 1 to 4, the contact force between the detection member and the conductive member can be adjusted. An ink level detection device featuring: