JPS6135961A - Liquid jet recording apparatus - Google Patents

Abstract

PURPOSE:To make it possible to certainly judge the clogging or ink exhausion of a recording head and the restored state thereof, by detecting the pulse of the change in liquid pressure based on the generation of emission pressure at the time of the emission of a liquid by the pressure sensitive means provided in the vicinity of an orifice. CONSTITUTION:When a power source is closed or when a recording head 1 was not used for a definite time, a carriage is moved to a non-printing region and predetermined pulse voltage is applied to a piezoelectric member 3. If a normal state is held, a pressure pulse almost generating no loss is detected by a pressure sensitive sensor 2. However, in such a state that no ink is present in the passage part 1D of an orifice member 1A, the pressure pulse is not sensed and, even when clogging is generated, no pressure pulse is sensed. When clogging is generated only in the vicinity of the orifice of the orifice member 1A, the pressure wave form from the pressure sensitive sensor 2 becomes abnormal. When restoration is impossible, a suction pump or pressure pump is operated to forcibly restore a normal state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Public Fund] The present invention relates to a liquid jet recording device, and more particularly to a liquid jet recording device having an on-demand type liquid jet recording head.

[Prior art]

In this type of print head, if ink evaporates or sticks in the orifice, or if the orifice becomes clogged with dirt or ink runs out in the ink ejection energy generating section, droplets will not be ejected in accordance with the print signal, and the print head will not print. The problem is that it lacks stability. Therefore, in order to solve these problems, in addition to the conventional manual recovery operation, the system automatically performs a dry discharge when the system is not operated for a certain period of time or when the power is turned on. Automatic recovery operations such as

However, manual operation is highly dependent on the individual judgment of the operator and requires trial and error.1. There is a problem of uncertainty in that after one recovery operation, actual ink ejection is performed and the recovery operation is repeated again depending on the quality of the discharge.

〔the purpose〕

In view of such problems, an object of the present invention is to provide a means for detecting ink clogging and ink shortage in an orifice portion, and when these conditions are detected through this detecting means, a corresponding recovery operation is performed. It is an object of the present invention to provide a liquid jet recording device that is capable of performing the above operations and issuing a warning.

[Summary of the invention]

In a liquid jet recording apparatus equipped with a liquid jet recording head equipped with an energy generating body that generates energy for ejecting a liquid, the liquid jet recording head includes a sensor near the orifice for detecting a change in liquid pressure. It is characterized by being provided with pressure means.

〔Example〕

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

1 and 2 illustrate a preferred embodiment of the invention.

1st B! ! In I, 1 is a recording head, IA is an orifice member fixed to the tip of a hard glass tube IB, and 10 is a flexible tube made of, for example, plastic for supplying ink and attached to the rear end of the hard glass tube IBO.

In this example, a pressure sensor 2 is disposed in the liquid passage part ID of the orifice member IA, and the pressure sensor 2 is used to detect the liquid passage part ID.
Detect the fluid pressure at Furthermore, 3 is a cylindrical piezo member covered around the hard glass tube IB;
The lead wire 3A is connected to the oscillation circuit 4 as shown in FIG.
It is connected to the central processing unit CPU 5, and applies a waveform voltage to the piezo member 3 via the oscillation circuit 4' in response to a signal from the 0PU5.

2 is a signal line that sends the pressure detection signal from the pressure sensor 2 to the pressure detection circuit 6, and the information from the pressure sensor 2 obtained via the pressure detection circuit 6 is input to the CPU S. . Reference numeral 7 denotes a carriage on which a supply tank 8 is mounted together with the recording head 1. By moving the carriage 7 parallel to the axis of the platen 9, the platen 9 is held by droplets ejected from the recording head 1. Dots are recorded on the recording paper 10. 8m and 8B are 4p flexible ink supply pipe and pressure pipe to sub tank 8.
, IF is a filter for removing foreign matter attached to the flexible tube IC.

Furthermore, the ink supply pipe 8A to the sub-tank 8 is led to an ink supply tank 11 as shown in FIG. 3, and ink can be replenished from the supply tank 11 to the sub-tank 8 via this supply pipe 8A.

Further, the pressurizing pipe 8B can supply pressurized air to the supply tank 11 via the pressurizing pump 12.

Reference numeral 13 denotes an ink suction cap that can be attached and detached to the orifice member of the recording head 1. In FIG. 3, the cap 13 is shown attached to the head 1. During the recovery operation, the carriage 7 is guided to the non-printing area and placed in the front mounting state. 14 is a suction pump 1, and 15 is a waste liquid tank.

Next, the recording head clogging detection operation and its recovery operation in the liquid jet recording apparatus configured as described above will be described. As described above, ink is constantly replenished from the supply tank 11 to the sub-tank 8, and is further guided from the sub-tank 8 to the recording head 1. When a voltage is applied to the piezo member 3, the ink is constantly supplied to the sub-tank 8. Piezo member 3
The deformation causes a volume change in the energy application chamber, and according to this volume change, ejection energy is applied to the ink, and droplet ejection pressure is generated in the ink.

Therefore, this pressure causes the ink to be ejected from the orifice provided at the tip of the orifice member IA, thereby making it possible to record dots on the paper 10.

゛In the recording apparatus of the present invention, when the power is turned on or when the recording head 1 is not used for a certain period of time, the carriage 7 is first moved to a non-printing area and a predetermined pulse voltage is applied to the pinion member 3. . Therefore, if the recording head 1 is in a normal state where it is not clogged, the pressure sensor 2 detects a pressure pulse with almost no loss corresponding to the applied pulse voltage.

However, if there is no ink in the passage ID of one Oriais member, the pressure sensor 2 will not sense a pressure pulse, and if there is enough ink in the hard glass tube IB in such a state, the piezo By applying a pulse voltage to the member 3 several times, a normal pressure pulse can be obtained from the pressure sensor 2, and it can be determined that the recording head 1 has returned to a normal recordable state.

Furthermore, in the Oriais member IA, the passage portion ID
If clogging occurs in the piezo member 3, no pressure pulse is detected from the pressure sensor 2 even if a pulse voltage is applied to the piezo member 3, and clogging occurs only in the vicinity of the orifice in the orifice member IA. In such a case, if the passage ID is in the form of a tube with one end closed, the pressure waveform output from the pressure sensor 2 will be abnormal. In addition, even in such a case, if there is ink inside the glass tube IB as described above, if the clogging is mild, it is possible to restore the state by applying a pulse to the piezo member 3. It is possible.

If a normal pressure waveform is still not obtained from the pressure sensor 2 even after the above operations, cover the suction cap 13 with the Oriace member IA as shown in FIG.
The pressure pump 12 is operated together with the suction pump 14 to forcibly feed ink into the head 1 while sucking ink from one oriice member to eliminate clogging υ.

After such an operation, it is only necessary to apply a pulse to the piezo member 3 and judge whether the pressure pulse from the pressure sensor 2 is normal or not. If a normal waveform is not obtained, repeat the above operation. , if it still doesn't recover, try the second one, for example.
The abnormality is notified by the warning lamp 16 shown in the figure or the like.

In this example, the piezo member 3 has a cylindrical shape, but the shape of the piezo member is not limited to this, and may be square or flat. Furthermore, the means for changing the volume of ink in the glass tube IB is not limited to the piezo member as in this example that utilizes the piezo effect, but an electrothermal converter is used as the ejection energy generator to perform the conversion. It is also possible to utilize a pressure change caused by a change in the state of the ink liquid by heating the ink liquid by applying electricity to the body to generate heat.

〔effect〕

As explained above, according to the present invention, the recording head has a discharge pressure generating means, and the discharge pressure generating means discharges liquid from the georifuge, and the liquid jet is performed by recording with the droplets. In a recording device, a pressure-sensitive means capable of detecting a change in liquid pressure is provided near the orifice, and this pressure-sensitive means detects a pulse of a change in liquid pressure based on the ejection pressure generated during ejecting the liquid, thereby preventing the eye caused in the print head. Not only can clogging, ink exhaustion, and their recovery states be accurately determined from the above-mentioned pulse generation, but recovery operations that deal with these situations can be performed quickly and easily.
It is also possible to generate a warning.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the configuration of a recording head in a liquid jet recording apparatus of the present invention, FIG. 2 is a diagram schematically showing the configuration of a device for detecting clogging, etc. in the recording head, and FIG. 1 is a diagram schematically showing the configuration of a clogging recovery device used in the liquid jet recording apparatus of the present invention. FIG. 1... Recording head, IA... Orifice section, 1B... Glass tube, IC... Flexible tube, ID... Liquid passage section, 1F... Filter 1 2... Pressure sensitive sensor , 2 people...signal line, 3...piezo member, 3A...lead wire, 4...oscillation circuit, 5...central processing unit, 6...pressure detection circuit, 7... - Carriage, 8... Sub tank, 8A... Ink supply tube, 8B... Pressure tube, 9... Platen, 10... Recording paper, 11... Ink supply tank, 12... Pressure Pressure pump, 13... Cap, 14... Suction pump, 15... Waste liquid tank, 16... Warning lamp.

Claims (1)

[Scope of Claims] Liquid ejection comprising a liquid ejection recording head that includes an orifice for ejecting liquid, a liquid flow path communicating with the orifice, and an energy generator that generates energy for ejecting the liquid. A liquid jet recording apparatus, wherein the liquid jet recording head is provided with a pressure sensitive means for detecting a change in liquid pressure near the orifice.