JPH0630908B2 - Electrostatic recording head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrostatic recording head, and in particular, an ion generating section in which a pair of discharge electrodes are superposed and arranged via an insulating layer is used. To an improved electrostatic recording head.

[Prior Art] A conventional electrostatic recording head is disclosed in, for example, Japanese Patent Laid-Open No. 59-1641.
54 and 59-190854 are listed in each publication. As shown in FIG. 4, the discharge wire 1 and a shield 2 surrounding the discharge wire 1 constitute an ion generator, and an ion discharge path 3 is opened in the shield 2 for introducing compressed air. While the air introduction path 4 is opened, the ion discharge path 3 has an appropriate number of control electrodes 5 arranged according to the pixel density.

In this type, a high DC voltage 7 is applied to the discharge wire 1.
When a voltage is applied, a discharge is generated between the discharge wire 1 and the shield 2, a large amount of ions are generated from the periphery of the discharge wire 1, and are guided to the ion discharge path 3 side together with the introduced compressed air. At this time, when an appropriate image control signal 8 is applied to the control electrode 5, the ion flow passes or is blocked depending on the presence or absence of an electric field in each control electrode 5, whereby the image control voltage is applied to the recording medium 6. That is, an electrostatic latent image corresponding to the above is formed.

[Problems to be Solved by the Invention] However, in such a conventional electrostatic recording head, the ions generated around the discharge wire 1 are directed radially toward the shield 2 side. Since a part of the ions is taken out to the side of the ion discharge path 3 together with the compressed air, there is a problem that the absolute amount of ions cannot be sufficiently secured, which is not suitable for high speed recording.

As a means for solving such a problem, for example, one shown in FIG. 5 can be considered. This is a head main body 10 in which an ion flow passage 13 is formed between a flat plate-shaped insulating member 11 and an insulating member 12 having a semi-cylindrical recess, and a flat plate-shaped insulating member 11 facing the ion flow passage 13. A pair of discharge electrodes 21, 22 provided on a part of the
An ion generating part 20 formed by superposing the two via an insulating layer 23.
A control electrode 31 corresponding to the pixel density and a counter control electrode 32 facing the control electrode 31 are provided between the insulating members 11 and 12 located near the outlet of the ion flow passage 13, and both control electrodes 31 and 32 are provided.
An ion flow control unit that controls the passage and blocking of the ion flow generated by the ion generation unit 20 by appropriately applying the image control signal 33 in between
It consists of 30 and. Reference numeral 35 is a DC bias power source that applies a predetermined electric field between the outlet portion of the head body 10 and the recording body 6 to guide only positive ions to the recording body 6 side.

According to this type, high frequency high voltage is applied between the discharge electrodes 21 and 22.
When 24 is applied, electric fields having different directions are alternately formed between the discharge electrodes 21 and 22. At this time, as shown in FIG.
By the electric field, the air near the edge portion 22a of the discharge electrode 22 facing the ion flow path 13 is broken by insulation waves, and positive and negative ions are alternately generated from the edge portion 22a, but to the discharge electrodes 21 and 22. Since the polarity of the applied voltage of (1) changes at high speed, the ion group is gradually trapped and propagated, and this ion group is immediately carried away to the recording body 6 side together with the compressed air introduced into the ion flow path 13. Therefore, the absolute amount of ions reaching the recording medium 6 is set to be larger than that of the type shown in FIG.

However, at this time, since the ions are generated in the ion generation unit 20, and then the generated ions are controlled by the ion flow control unit 30, the two are functionally separated, which is inevitable. Therefore, the ion generator 20 and the ion flow controller 30 have a certain distance l along the ion flow passage 13.
Will be spaced apart. In this case, some of the ions generated by the ion generator 20 are partially
Since the ion flow path 13 is neutralized by colliding with a wall surface or the like in the ion flow passage 13 until reaching the ion flow path, the absolute amount of the ions extracted substantially by the amount of ion loss until reaching the ion flow control section 30. Was reduced, which was an obstacle to high-speed recording.

[Problems to be Solved by the Invention] The present invention has been made in view of the above problems, and it is possible to improve ion extraction efficiency while simplifying the configuration. An electrographic recording head is provided.

That is, according to the present invention, a head body in which an ion flow path is formed between opposing insulating members, a pair of discharge electrodes are superposed on one insulating member via an insulating layer, and the discharge electrodes are sandwiched between them. An ion generator to which a high frequency high voltage is applied, and control electrodes are arranged on the other insulating member facing the ion generator according to the pixel density, and each control electrode also serves as the one discharge electrode. An image control signal is applied between the counter control electrode and an ion flow control unit that controls the passage and interruption of the ion flow generated in the ion generation unit.

In such technical means, the shape and size of the insulating member constituting the head main body may be appropriately selected, but the ion generating portion and the ion flow control portion may be provided at substantially the same location in design. Therefore, it is not necessary to secure the ion flow passage so long. Also, regarding the ion generation part, if the high-frequency high voltage is applied between the discharge electrodes arranged with the insulating layer sandwiched, the size and arrangement relationship of the discharge electrodes will depend on the amount of generated ions required. Although the design may be changed as appropriate, in order to further improve the ion generation rate, a large number of cut recesses are provided in the discharge electrode on the side facing the ion flow passage, thereby substantially functioning as an ion generation section. It is desirable to design to increase the edge area. Furthermore, as the ion flow control unit, at least, an image control signal is applied to the control electrode side provided on the insulating member facing the ion generation unit,
Of the discharge electrodes, one that is kept at the ground potential may be selected as the counter control electrode. Furthermore, as a method of transferring the generated ions to the recording body side, it is possible to appropriately select by introducing compressed air into the ion flow passage, forming an electric field for guiding the ions between the head and the recording body in advance. It doesn't matter.

[Operation] According to the technical means as described above, when a high frequency high voltage is applied between the pair of discharge electrodes of the ion generating part, the dielectric breakdown of air is caused at the edge portion of the discharge electrode on the side facing the ion flow passage. Then, a lot of ions are generated from this part. Then, many generated ions are immediately passed through and blocked by an ion flow control unit provided at substantially the same site as the ion generation unit, and the passed ions move to the recording body side,
A predetermined electrostatic latent image is formed.

[Embodiment] The present invention will be described in detail below based on an embodiment shown in the accompanying drawings.

1 to 3, the basic structure of the electrostatic recording head includes a head body 10 in which an ion flow passage 13 is formed between flat insulating members 11 and 14, and an outlet portion of the ion flow passage 13. The ion generator 20 provided and the ion flow passage 13 are also provided.
And an ion flow control unit 30 provided at the exit portion of the.

In this embodiment, the ion generating section 20 is provided with a lower discharge electrode 21 on one insulating member 11 facing the ion flow passage 13, and an insulating layer 23 is provided on the lower discharge electrode 21. An upper discharge electrode 22 is provided and a high frequency high voltage 24 is applied between both discharge electrodes 21, 22. More specifically, the lower discharge electrode 21 is formed in a substantially rectangular shape, and is screen-printed with gold paste on the insulating member 11, and then formed into a predetermined shape by a photolithography process. To define. The insulating layer 23 is provided in a range that covers the lower discharge electrode 21, and is configured by screen printing baking with glass paste, for example. Further, the upper discharge electrode 22 is formed into a predetermined shape by screen printing on the insulating layer 23 with gold paste, and then performing a photolithography process.

Then, in this embodiment, the upper discharge electrode 22 is
The lower discharge electrode 21 is superposed on the entire region except one side edge thereof, and one side edge of the upper discharge electrode 22 is slightly protruded from the other side edge of the lower discharge electrode 21. The upper discharge electrode 22 has a large number of cut recesses 25 in the range where the upper discharge electrodes 21 are assembled, and the cut recess 25 groups are formed in a comb shape. Further, the cut recesses 25 are formed with a density of, for example, about 4 pieces / mm, and the width dimensions of the cut recesses 25 and the branch portions 26 formed between the cut recesses 25 are set to be substantially equal to each other. ing.

In addition, the ion flow control unit 30 has a pixel density (for example, 12 pixels) on the surface of the insulating member 14 facing the trunk portion 27 of the upper discharge electrode 22.
(A number of lines / mm), the control electrodes 31 are divided and arranged, and the counter control electrodes 34 that also serve as the backbone 27 of the upper discharge electrode 22 and are kept at the ground potential. The image control signal 33 according to the pattern is applied. Reference numeral 35 is a DC bias power source similar to the conventional example.

Therefore, according to the electrostatic recording head of this embodiment,
Now, high-frequency high voltage is applied to each discharge electrode 21, 22 of the ion generator 20.
When 24 is applied, electric fields with different directions are alternately formed in the overlapping portion area of each discharge electrode 21, 22. At this time, the edge portion 22a of the upper discharge electrode 22 on the side facing the ion flow passage 13
In the vicinity, the dielectric breakdown of air occurs, and positive and negative ions 40 are alternately generated from the edge portion 22a, and the generated ions 40 are gradually trapped and proliferated as the polarity of the applied voltage rapidly changes. Particularly, in this embodiment, firstly, since the edge portion 22a is constituted by the inner edge of the cut recess 25 and the projecting edge of the branch portion 26, the edge portion 22a is
Area, in other words, the production area of the ions 40 is sufficiently wide, and the production amount of the ions 40 can be increased accordingly. Secondly, the substantial overlapping area between the discharge electrodes 21 and 22 is Since it is reduced by the presence of the recess 25, the capacitance between the discharge electrodes 21 and 22 is set small, and accordingly, the current for charging and discharging the insulating layer 23 is The discharge electrode 21, which is suppressed to a relatively small one,
It is possible to reduce the power consumed between 22 and.

Then, the ions 40 generated by the ion generator 20 are
Immediately, it reaches the ion flow control unit 30 provided at substantially the same location as the ion generation unit 20. At this time, when an appropriate image control signal 33 is applied to the control electrode 31, an electric field is generated between the control electrode 31 to which the image control signal 33 is applied and the counter control electrode 34 in a direction orthogonal to the ion flow passage 13. Will be formed. Then, the corresponding ion 40 portion moves to the control electrodes 31, 34 side by the electric field and is neutralized and disappears at the portion, so that the ion flow is blocked in the electric field forming portion, while in the electric field non-forming portion. Ion 40 is the ion flow path 13
The compressed air guided to the recording medium 6 passes toward the recording medium 6 side, and an electrostatic latent image based on the ion flow is formed on the recording medium 6. At this time, since the distance between the ion generation unit 20 and the ion flow control unit 30 is set to substantially zero, there is no possibility that the generated ions 40 will be lost on the way to the ion flow control unit 30. Effectively avoided. Also, since the loss of the ions 40 is suppressed, it is not necessary to set the ion flow velocity unnecessarily high,
The compressed air flow can be reduced, and the compressed air generator can be downsized.

In the above embodiment, the cutout recess of the upper discharge electrode 22.
If the formation density of 25 is set to be smaller than the pixel density, even if the ion generation distribution from the upper discharge electrode 22 varies to some extent, the variation is effectively absorbed and each pixel of the ion flow control unit 30 is supported. It is possible to make the amount of ions passing through the portion substantially uniform. At this time, the potential of the electrostatic latent image dots can be maintained substantially uniform,
The uneven density of the developed toner image can be reliably avoided. Further, in the above-mentioned embodiment, the lower discharge electrode 21 is also formed with the same recessed recess as the upper discharge electrode 22, so that the substantially overlapped area of both discharge electrodes 21, 22 is reduced as much as possible. , 22 further reduce the capacitance,
It is possible to further reduce the power consumption between the discharge electrodes 21 and 22.

[Effects of the Invention] As described above, according to the electrostatic recording head of the present invention, the electrostatic recording head has the ion generating portion with high ion generation efficiency, and moreover, the ion generating portion is generated at substantially the same position in the ion flow passage. Since the section and the ion flow control unit are provided, it is possible to eliminate the loss of ions on the way from the ion generation unit to the ion flow control unit, and immediately generate a large amount of ions generated in the ion generation unit. It can be sent to the recording medium side by guiding it to the ion flow controller. Therefore, it is possible to sufficiently secure the absolute amount of ions, and the higher speed recording can be realized accordingly.

Further, according to the present invention, one of the discharge electrodes, which is a constituent member of the ion generating unit, is also used as one constituent member of the ion flow control unit, so that the head structure can be simplified.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the electrostatic recording head according to the present invention, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 3 is an arrow seen from a direction III in FIG. FIG. 4 is a sectional explanatory view showing an example of a conventional electrostatic recording head, FIG. 5 is a sectional explanatory view showing another example of a conventional electrostatic recording head, and FIG. 6 is a VI in FIG. It is an arrow view seen from the direction. [Explanation of symbols] (10) …… Head body (20) …… Ion generator (21,22) …… Discharge electrode (23) …… Insulating layer (25) …… Incision recess (30) …… Ion flow Control unit (31) …… Control electrode (34) …… Counter control electrode

Claims (2)

[Claims] 1. A head body in which an ion flow path is formed between opposing insulating members, a pair of discharge electrodes are superposed on one insulating member via an insulating layer, and a high frequency wave is placed between the discharge electrodes. An ion generating portion to which a high voltage is applied, and a control electrode arranged on the other insulating member facing the ion generating portion according to the pixel density and facing each control electrode and the one discharge electrode. An electrostatic recording head comprising: an ion flow control unit that controls the passage and interruption of an ion flow generated by an ion generation unit when an image control signal is applied between the control electrode and the control electrode. 2. The electrostatic recording head according to claim 1, wherein the discharge electrode on the side facing the ion flow passage has a large number of recesses.