Inkjet recording head and inkjet recording apparatus having the same

Abstract

An inkjet recording head includes a passage communicating with a discharge port for discharging ink, a discharging heater provided in the passage for generating energy to discharge ink from the discharge port, and a detecting unit provided in the passage for detecting a temperature of ink that changes in accordance with heat energy generated by the detecting unit and a flow of ink in the passage.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to inkjet recording apparatuses, and more particularly, to an inkjet recording apparatus that can detect defective discharging. Herein, the term “recording” includes applications of ink (printing) to ink support materials such as cloth, strings, paper, and sheet materials. The term “recording apparatus” includes various information apparatuses and printers serving as output devices of the apparatuses.[0003]2. Description of the Related Art[0004]Along with the popularization of information processing apparatuses such as copying machines, word processors, and computers, recording apparatuses (inkjet recording apparatuses) that perform recording with an inkjet recording head have been rapidly popularized as output (recording) apparatuses for the information processing apparatuses.[0005]In general, an inkjet recording apparatus includes a carriage on which a recording head and an ink tank are m...

AI Technical Summary

Benefits of technology

[0020]The present invention provides an inkjet recording head that overcomes the above-described problems and that can accurately detect ink discharging failure with a high throughput, and an inkjet recording apparatus using the inkjet recording head.

[0024]The magnitude of the ink flow in the case of discharging failure has a sufficiently distinguishable difference from that during normal discharging. Therefore, it is possible to accurately distinguish between normal discharging and defective discharging.

[0025]Further, the detection accuracy will not be reduced by external influence, unlike the optical defective-discharging detecting device. This allows for highly accurate detection.

[0028]According to the present invention, the detecting unit generates heat energy in response to generation of energy by the energy generating element, and the temperature of the ink is then detected. Therefore, it is possible to further increase the accuracy in detecting ink discharging failure.

Problems solved by technology

Further, if a minute bubble, which grows in the ink in the ink passage for discharging, remains in the ink passage, normal ink discharging is sometimes difficult.

This phenomenon of defective discharging due to the remaining bubble pronouncedly appears when the print duty is relatively high.

In another case, a bubble enters the ink at a connecting portion of an ink supply passage or an ink supply system, and clogs the ink supply passage.

If recording failure is caused by the above-described defective ink discharging, the recording medium is wasted, and the time taken for recording is also wasted.

If unclear images are continuously recorded in a so-called “faded recording” state caused immediately before defective discharging occurs, multiple recording media are wasted.

Further, if recording is continued in the “faded recording” state, the recording head is heavily loaded, and this sometimes destroys the recording head itself.

Unfortunately, the above-described inkjet recording apparatus has the following problems.

Therefore, it is difficult to make judgment about defective discharging of ink with respect to each discharge port.

In this case, however, the change in output from the light-receiving portion caused when one ink droplet blocks the optical path is small, and therefore, it is difficult to make an accurate judgment about defective discharging of ink.

Further, the optical defective-discharging detecting device is susceptible to external light, which also makes detection of defective discharging difficult.

In this way, it is difficult to make an accurate judgment about defective discharging with respect to each discharge port.

Moreover, a defective-discharging detecting operation cannot be performed during recording on a recording medium.

This defective-discharging detecting operation decreases the throughput of the recording apparatus.

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