JPH02102061A - Ink level detection device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION] Industrial Application Field 1 The present invention relates to a remaining ink amount detection device in an inkjet recording apparatus.

1. Prior Art 1. A remaining ink amount detection device using a photodetector is conventionally known. There is a method of detecting the remaining amount of ink by detecting changes in reflected light due to displacement of the ink container by configuring the other part facing this with a light reflective member. In this type of remaining ink level detection device, the ink container must be made of a transparent flexible member, and the structure depends on the displacement of the ink container, so variations in the displacement of the ink container are avoided. The disadvantage of greatly reducing detection accuracy was an unavoidable problem. Furthermore, since the absorption spectrum of light differs depending on the coloring material of the ink present in the optical path, there are restrictions such as the need to select a light emitting source with an emission spectrum that corresponds to the ink, or to select an ink that is suitable for the light source. I have a problem.

1 nM + The present invention aims to solve these problems and provides a highly accurate remaining ink amount detection device with a simple structure and higher reproducibility.

1 Means for Solving the Problems 1 That is, the present invention has a structure in which a light reflection plate is provided in the ink reservoir and a photodetector is placed in a position opposite to the light reflection plate, so that it must depend on the displacement of the ink container. This eliminates these constraints and makes it possible to detect the remaining amount of ink with high precision without having to select a light source depending on the coloring material of the ink.

lExample 1 The illustrated embodiment will be described below.

Figure 1 shows a cross section of an inkjet head.
This inkjet head 1 is mounted on a carriage that runs in the axial direction of a platen 2.

A piezoelectric transducer 5 is attached to the back surface of a nozzle plate 4 having a plurality of nozzles 3 via a spacer. A regulating plate 8 is provided behind the piezoelectric transducer 5 to maintain the distance between the ink chamber 7 and the ink reservoir 6 to about 0.2 to 2.0 layers. Ink is constantly supplied from the reservoir through the ink supply path 10 to a level above the axis of the nozzle by capillary action.

By the way, at least two or more partition plates 11 are provided in the ink reservoir in order to suppress fluctuations in the ink liquid level that occur as the carriage travels. Furthermore, a photodetector 14, which is a combination of a light emitting element 12 and a light receiving element 13, is fixed on the upper wall surface, and a light reflecting plate 15 whose surface is treated to be water repellent is fixed on the lower wall surface.

Here, the photodetector 14 is located at a position separated by light from the ink liquid surface, and is installed so that the light hits the light reflecting plate 15 directly, and the light reflecting plate 15, which is constantly immersed in the ink, is set If ink is consumed beyond the value, the ink will be exposed above the liquid level.

When a detection signal is applied to the light emitting element from the transmitting circuit in the detection circuit block diagram shown in Fig. 2, light is emitted from the light emitting element consisting of a photodiode, and when the light reflecting plate is exposed from the ink liquid surface. Here, the light is reflected and taken into a light receiving element consisting of a phototransistor. When the phototransistor senses light, the relative light-receiving current value changes rapidly, and a logic signal is output through a rectifier circuit, making it possible to detect the end of ink. When the light reflecting plate is immersed in ink, the light emitted from the light emitting element is absorbed by the ink, so no change in the relative light reception current value is observed in the light receiving element. The wavelength of the light emitted by the photodiode is preferably 600 nm or more, which is less susceptible to the effects of external light, but since the optical path is in the air and not in the ink, there is no need to take into account the absorption spectrum of the ink. There are no restrictions.

FIG. 3 shows a remaining ink amount detection device according to another embodiment of the present invention. A part of the partition plate disposed inside the ink reservoir is also used as a light reflecting plate, and a photodetector is installed on the outer wall surface of the ink reservoir, a part of which is made up of a transparent member 16. Here, the light reflecting portion of the partition plate is treated to be water repellent, and it is possible to prevent erroneous detection due to residual ink. Furthermore, by performing N2T1 on at least two photodetectors, the remaining amount of ink can be managed in multiple stages, and it is possible to prevent the printing operation from stopping due to the sudden end of ink.

1 Effects of the Invention 1 As described above, according to the present invention, since the structure is simple, combining a photodetector and a light reflection plate, the ink reservoir can be used with a high degree of freedom in terms of the material, shape, etc. of the ink container. Since it is a direct detection method using light, it does not require any accompanying detection mechanism, and is ideal for downsizing inkjet heads. In addition, since we use a non-contact optical detection method for ink and the optical path for detection is in the air, it is possible to It has the advantage of being compatible with ink.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the remaining ink amount detector of the present invention, FIG. 2 is a block diagram of a detection circuit, and FIG. 3 is a diagram showing another embodiment of the present invention.・Inkjet head, nozzle, piezoelectric transducer, ink reservoir, ink, light-emitting element, light-receiving element, photodetector, light-reflecting plate, transparent member and more Applicant Seiko Epson Corporation Representative Patent Attorney Kisanbe Meiki and 1 other person No No Figure 1 Figure 3

Claims (1)

[Claims] In an inkjet recording device equipped with a remaining ink amount detection mechanism, a light reflecting plate is provided in an ink reservoir made of a rigid member, and a photodetector consisting of a light emitting element and a light receiving element is opposed to the light reflecting plate. An ink remaining amount detection device characterized by being arranged at a position.