JP2861523B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ink discharge port having a predetermined gap at an air discharge port, the ink discharge port having one communicating with an ink chamber disposed so as to face the air discharge port. By applying a predetermined pulse voltage intermittently between electrodes provided around the air discharge port and the ink discharge port in a state where the air flows out intermittently, the air flows from the ink discharge port together with the air flow. The present invention relates to an ink jet recording apparatus which discharges one dot on recording paper in response to the one pulse voltage by intermittently discharging from a discharge port, and in particular, means for equalizing the size of each dot printed on recording paper. It is characterized by the following.

[0002]

2. Description of the Related Art In recent years, the printer market has been expanding due to the widespread use of personal computers and word processors. Above all, an ink jet recording apparatus with low noise is expected in the future.

[0003] A conventional static control ink jet recording apparatus will be described below with reference to the drawings.

FIG. 3 is a sectional view of a principal part of an electrostatic control type ink jet recording apparatus. In FIG. 3, reference numeral 10 denotes an ink nozzle plate made of a glass material, on which ink discharge ports 9 are formed by an etching method or the like. Reference numeral 8 denotes an air nozzle plate made of a glass plate, on which an air discharge port 6 from which ink is discharged together with an air flow is formed by an etching method or the like. Reference numeral 12 denotes a gap through which air passes;
Numeral 9 enters through the air inlet 17 and always flows out of the air outlet 6 via the air chamber 13 and the gap 12. 1
Reference numeral 5 denotes a body made of ceramic or resin, which fixes the ink nozzle plate 10 and the air nozzle plate 8 to form an ink chamber 14 and the air chamber 13. Ink 20 enters through ink inlet 16. Reference numeral 11 denotes a signal electrode for applying a potential to the ink formed around the ink discharge port 9,
A pulse voltage is applied by the signal source 18.

A common electrode 7 is formed on the air nozzle plate 8 by a vacuum deposition method or the like. The principle of ink ejection is that the same air pressure is applied to the ink chamber 14 and the air chamber 13, and ink is supplied to the tip of the ink ejection port 9. The air passes through the narrow gap 12 and the air outlet 6
More always out. At this time, since the air in the gap 12 receives a slight pressure loss, the pressure in the ink chamber 14 becomes slightly higher, and as a result, the ink forms a convex meniscus at the tip of the ink discharge port 9. In this state, the signal electrode 1
When a potential difference is applied between the first electrode 1 and the common electrode 7, the ink is ejected in a thread form by the force, and is stably ejected from the air ejection port 6 toward the recording medium (not shown) while riding on the air flow. One dot is recorded for the voltage.

Now, when a pulse such as the signal A in FIG. 4 is applied to the signal electrode 11 from the signal source 18, ink is ejected in synchronization with the signal A, and one pulse is printed on the recording paper. One dot D1, D2, D3,... Is printed.

[0007]

However, as schematically shown in FIG. 4, one dot D2 is placed after the dot D1.
There is a problem that the size of the printed dot changes or the printing position shifts between the case where the dot is recorded and the case where there is a large number of dot sections where no printing is performed before the dot D3. . This phenomenon is caused by the fact that the shape of the meniscus formed in the ink discharge port is sufficiently large immediately after printing is performed, and the ink discharge is started immediately when a pulse is applied to the signal electrode 11. If there is no section, it is considered that the shape of the meniscus becomes small and the ejection is not started immediately even if the pulse is applied to the signal electrode 11.

[0008]

In order to solve the above-mentioned problems, an ink jet recording apparatus according to the present invention has an ink discharge port having a predetermined gap at an air discharge port and one of which is communicated with an ink chamber so as to face the air discharge port. In a state where air is intermittently discharged from the air discharge port through the gap,
By intermittently applying a predetermined pulse voltage between the air ejection port and an electrode provided around the ink ejection port, the ink from the ink ejection port is intermittently transmitted from the air ejection port together with the air flow. In an ink jet recording apparatus that discharges and prints one dot in response to the one pulse voltage on recording paper, a section where printing is not performed is detected, and a rise time of the pulse voltage is determined according to the length of the section. The pulse width is changed by changing the pulse width.

[0009]

According to the above construction, the shape of the meniscus of the ink discharge port at the position where printing is desired is added by adding a pulse signal having a time width corresponding to the section n where printing is not performed to the front side of the conventional print signal. The shape can be the same as that immediately after printing. For this reason, even when the section in which the printing is not performed becomes large, the change in the printing size and the printing position can be reduced.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a print control circuit of an ink jet recording apparatus according to one embodiment of the present invention, and FIG. 2 shows a control signal and a print output of the print control circuit.

In this embodiment, as shown in FIG. 1, an output signal A from a signal source 18 is passed through a delay circuit 1 for obtaining a delay signal B obtained by delaying the output signal A by a predetermined time T, an adder circuit 4, and a slice circuit 5. The signal is applied to the signal electrode 11 and is also applied directly to the detection circuit 2 for detecting a dot section where printing is not performed.

The detection circuit 2 detects the number n of dot sections in which printing is not performed, and outputs this number n to the next pulse generation circuit 3.

In the pulse generation circuit 3, the output signal A is converted into a delay time Tn (Tn <Tn) corresponding to the number of sections n.
A signal C delayed by T) is created. The signal C is added to the signal B by the adding circuit 4 to generate a signal D. Then, a signal E having a constant level is generated through the slice circuit 5 and applied to the signal electrode 11.

That is, a signal E in which the rising time of the signal A is changed in accordance with the number n of sections where no printing is performed is created and applied to the signal electrode 11.

[0016]

As described above, according to the present invention, a pulse signal having a time width corresponding to the interval n in which printing is not performed is added to the front side of the conventional printing signal, so that the ink ejection port at the position where printing is desired is performed. The shape of the meniscus can be made the same as the shape immediately after printing. For this reason, even when the section in which the printing is not performed becomes large, the change in the printing size and the printing position can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of an ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the embodiment.

FIG. 3 is a sectional view of a main part of a static control type ink jet recording apparatus.

FIG. 4 is a diagram illustrating the operation of the apparatus.

[Description of Signs] 1 delay circuit 2 detection circuit 3 pulse generation circuit 4 addition circuit 5 slice circuit 6 air discharge port 7 common electrode 9 ink discharge port 11 signal electrode 12 air gap 13 air chamber 14 ink chamber 18 signal source

Claims (1)

(57) [Claims] An ink discharge port, one of which is in communication with an ink chamber, is disposed so as to face the air discharge port with a predetermined gap, and air is passed from the air discharge port through the gap.
In a state where the ink is discharged intermittently, a predetermined pulse voltage is intermittently applied between the air discharge port and an electrode provided around the ink discharge port, so that the ink from the ink discharge port flows into the air flow. In addition, in an ink jet recording apparatus that discharges intermittently from the air discharge port and prints one dot on recording paper in response to the one pulse voltage, a section where printing is not performed is detected, and the length of the section is determined. An ink jet recording apparatus, wherein the pulse width is changed by changing the rise time of the pulsed voltage in response.