JPH05212897A - Electrostatic recording head - Google Patents

Abstract

PURPOSE:To provide an electrostatic recording head which enables an image forming device to meet the requirement of miniaturization or high density print and has the high durability and high reliability as well as the capability of easy manufacturing. CONSTITUTION:The title recording head is equipped with a discharge member having an induction electrode 2 and discharge electrodes 3-1, 3-2, terminal members 9-1, 9-2 which connect the discharge electrodes to a driving power source and a substrate 1 that supports the discharge member and terminal members. The terminal members are supported with the substrate near the discharge member, as another construction body which is separated with the discharge member, and connected to the discharge member with thin lead wires 10-1, 10-2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic recording head which is used in the field of discharge technology and which directly forms an electrostatic latent image according to an image signal on the surface of a charged body of an electrophotographic printer.

[0002]

2. Description of the Related Art As an electrostatic recording head of this type, an alternating current or a pulse voltage is applied between a dielectric electrode and a discharge electrode arranged in a matrix with a dielectric material sandwiched between the discharge electrode and the matrix electrode. Ion flow is radiated from the formed hole, and a bias voltage is applied to the control electrode placed on the discharge electrode via an insulator layer to control the ion amount of this radiated ion flow to the charged body. Are known (JP-A-54-78134 and JP-A-61-281254).

In this type of electrostatic recording head, a card edge connector, a pin terminal, a spring contact pin, etc. are connected in order to connect a discharge member composed of a discharge electrode and a dielectric electrode and a power source section for driving the discharge member. It is known that a member electrically connects the connection terminal portions formed on the discharge member and the power source portion. (JP-A-6
3-137859).

[0004]

However, in this prior art, the discharge member is a composite laminate of thin leaf members, and the terminal portion for connection with the power supply portion is
Forming the same member as the discharge member or a substantially integral member has the following drawbacks.

1. When using a pin terminal or a spring contact pin as a connecting member, it is necessary to provide a region of a connecting portion for disposing these at the end of the discharge member. This leads to an increase in size and hinders the downsizing of image forming apparatuses such as printers.

2. When the card edge connector is used as a connecting member to avoid upsizing, it is necessary to bend the end of the discharge member in the direction intersecting the discharge part to form the terminal part. The residual stress reaches the discharge part, and the risk of deformation, peeling, displacement, etc. of the laminate increases. This effect is particularly noticeable when used over a long period of time under the condition that repeated micro-deviation occurs due to the difference in thermal expansion / contraction between the constituent members of the composite laminate forming the discharge part, and the decrease in adhesive strength of the adhesive for lamination. There is a risk of delamination of the electrostatic recording head and definite damage such as displacement of constituent members, resulting in a marked decrease in durability and reliability. On the other hand, in order to reduce the influence of bending, thinning the bent portion of the discharge member or narrowing the pattern width reduces the handleability of the discharge member in the assembly process and makes the work difficult.

3. In high-density and large-size electrostatic recording heads, the number of matrix elements, that is, the number of connection terminals, increases, so that the total contact pressure of the connection members for ensuring electrical connection becomes a large value. As a result, the risk of the terminal portion deforming is increased, and further the influence of the deformation is exerted on the discharge portion integrated with the terminal portion, resulting in damage such as peeling and displacement of the laminated body. Increasing the strength of the terminal portion or the device body supporting the terminal portion in order to prevent this deformation leads to an increase in the size of the device.

4. In the discharge member in which the discharge part and the terminal part are integrated, it is necessary to maintain the positional accuracy of the discharge part and the terminal part with respect to the base body at the same time in the assembly process, which makes it extremely difficult to manufacture and assemble parts.

The present invention solves the above-mentioned problems of the conventional electrostatic recording head, and is compatible with downsizing and high density of the image forming apparatus, and has high durability and reliability. An object is to provide an electrostatic recording head that is easy to manufacture.

[0010]

An electrostatic recording head according to the present invention comprises an ion discharging discharge member and the discharge member.
In an electrostatic recording head comprising a terminal member for connecting to a driving power source thereof, and a base member supporting the discharge member and the terminal member, the terminal member is a structure separate from the discharge member, It is characterized in that it is supported in the vicinity of the discharge member by the base body and is connected to the discharge member by an electrical connecting means.

[0011]

Operation: The current supplied from the driving power supply to the terminal member is
It is supplied to a discharge member provided separately from the terminal member via an electrical connecting means. As a result, ions are ejected from the discharge member.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of an electrostatic recording head according to the present invention. In this figure, the discharge member for emitting ions is composed of a plurality of narrow conductors 2-1 and 2-2 extending parallel to each other at a predetermined interval in the longitudinal direction of the electrostatic recording head (direction of arrow A in the figure). 2, and a plurality of discharge electrodes 3 that extend in a different direction from the flat induction electrode 2 and are installed independently via a dielectric layer 5 and are arranged in a matrix with a narrow conductor. 1, 3-2, ... (shown by reference numeral 3 in FIG. 2)
And the control electrode 4 arranged on the discharge electrode via the insulator layer 6, which are integrally laminated and installed on the base (substrate) 1. At the positions corresponding to the above-mentioned matrix intersections in the discharge electrode 3 and the control electrode 4, openings for ion emission are provided respectively. Connection parts 7-1, 7-2, ... For supplying power to the respective narrow conductors are formed at the ends of the induction electrode 2, while the discharge electrodes 3-1, 3-2 ... Are formed so that they extend in mutually opposite directions and intersect with the narrow conductors, and these intersections become matrix intersections.
-2, ... (See FIG. 2) are connecting portions for power feeding.

On the substrate 1, a pair of terminal members 9 adjacent to both sides of the discharge member in the longitudinal direction for connecting to a power supply circuit section for driving the electrostatic recording head are provided.
-1, 9-2 are installed. The terminal member is a thin plate-like member in which conductor terminal patterns for connection are formed at respective positions corresponding to the connecting portions 7-1, 7-2, ... Of the induction electrode and the end portion of the discharge electrode. A thin conductive wire 10 is provided between one end of the terminal pattern and the terminal portion of each electrode of the discharge member.
-1, 10-2, ... 10-n, 10-n ₁ ...
The other end of the terminal pattern forms a connection with the power supply circuit.

FIG. 2 is a cross-sectional view of the electrostatic recording head shown in FIG. 1 installed in a direction orthogonal to the direction A in FIG. Here, the electrostatic recording head is arranged so that its center line in the width direction intersects at right angles with the rotation center axis of the dielectric drum 11, and the control electrode 4 is arranged so as to face the dielectric drum 11 while maintaining a minute gap. .. In order to connect the terminals of the terminal members 9-1 and 9-2 to both sides of the lower part of the electrostatic recording head, a plurality of feeding contact pieces 12-1 and 12 corresponding to the terminal patterns of the terminal members are connected. A pair of power supply circuit boards 13-1 and 13-2 having -2, ... arranged thereon are provided, and the electrostatic recording head maintains the contact between the contact piece and the terminal member while maintaining the above-mentioned minute gap. It has been installed.

In the electrostatic recording head shown in FIGS. 1 and 2, the thickness of the dielectric layer 5, the insulating layer 6, the induction electrode 2, the discharge electrode 3 and the control electrode 4 is set in the range of 10 to several tens of μm. The structure is such that these members are laminated and integrated. On the other hand, since the required current for maintaining the generation of ions is very small, the terminal members 9-1, 9-2
The thin conductive wire 10 for electrically connecting the lead electrode 2, the discharge electrode 3 and the induction electrode 2 is a thin conductive wire made of aluminum, gold, or the like, and both ends of the thin conductive wire 10 are connected by the wire bonding method to the terminal members 9-1, 9-2 and It is fused to the induction electrode 2 and the discharge electrode 3.

When a force in the bending direction is applied to the above-mentioned laminated body constituting the electrostatic recording head, the laminated layers are peeled off between the respective constituent members,
There is a property that relative displacement easily occurs. On the other hand, in order to ensure electrical contact at the power supply contact part, a contact pressure of several tens of grams is usually required per contact part, and since the number of contact parts is large in a matrix-arranged electrode configuration, the total amount of contact pressure is large. Is a large value. For example, when printing with A4 size at a resolution of 300 dots / inch, about 2500 ion emission holes are required, and if this is composed of a matrix of 12 * 210 of the induction electrode 2 and the discharge electrode 3, 222 connection parts are formed. Occurs. Therefore, the total amount of contact pressure reaches several kilograms to a dozen kilograms. For this reason, in the electrostatic recording head in use, excessive force is applied to the terminal member and the terminal member support portions (both upper portions) of the base body, and bending and deformation are likely to occur. In the electrostatic recording head of the present embodiment, since the ion generating portion and the terminal portion are connected only by a thin conductive wire that makes electrical connection as described above, the influence of the deflection and deformation generated at such a terminal portion is It does not extend to the ion generator.

3 and 4 show a second embodiment of the electrostatic recording head according to the present invention, and the same components as those in the first embodiment are designated by the same reference numerals. In FIG. 3, the base body 21 is formed of a hollow block body having a rectangular cross section, and a plurality of (three) mounting bodies for mounting the discharge electrode 3 and a pair of terminal members 9-1 and 9-2 on the outer peripheral surface thereof. It has a table surface. Of these, the mounting surfaces of the terminal members 9-1 and 9-2 are the induction electrodes 2,
One of the dielectric layers (not shown), the discharge electrode 3, the insulator layer (not shown), and the control electrode 4 that are opposed to each other in the direction orthogonal to the outer surface (top surface) on which the ion discharge portion is placed. It is composed of the outer surface (side surface) of the set. Terminal members are installed on these mounting surfaces, respectively. The width and the length of the base 21 are set to be substantially the same as the width and the length of the induction electrode 2, so that when the discharge member is placed on the base, no protrusions larger than the width of the base are generated. Is becoming
The connection portion pattern of the induction electrode 2 is arranged along one of the longitudinal edges of the induction electrode, and is configured so that power is supplied to all induction electrode patterns by the terminal member 9-1 on one side. Similar to the first embodiment, the connection between the induction electrode 2 and the discharge electrode 3 and the terminal members 9-1 and 9-2 are electrically connected by the thin conductive wire 10, and an electric signal from the terminal member is generated. Are supplied to the induction electrode 2 and the discharge electrode 3, respectively. These conducting wires 10 are wired along the longitudinal direction of the surface of the induction electrode 2 and the terminal member at a predetermined interval from each other.

FIG. 4 shows the structure of the second embodiment in the direction orthogonal to the B direction shown in FIG. Here, the pair of power supply circuit boards 13-1 and 13-2 includes terminal members 9-1 and 9-.
A plurality of power supply contact pieces 12-1, 12-2, ..., which are respectively in contact with the respective terminals of No. 2 and which supply power to these terminals, are arranged side by side on the inner surface of the substrate, and a vertical surface passing through the central axis of the dielectric drum 11. Are arranged symmetrically with respect to.

With the above-described structure, in the electrostatic recording head having the structure shown in the second embodiment, the connecting terminal member is arranged on the side surface of the head, and the head width is substantially equal to the discharge member width. The width of the head itself is
It can be made smaller than that shown in the embodiment.

Further, since a pair of power supply circuit boards for supplying power to the electrostatic recording head are arranged so as to sandwich the electrostatic recording head in a direction perpendicular to the center of the dielectric drum, the pair of power supply circuit boards are constituted by this head and the power supply board. It is possible to reduce the area occupied by the electrostatic recording unit on the surface of the dielectric drum, and particularly in a downsized image forming apparatus, it is easy to arrange the developing device, the cleaning device, the static eliminator and the like around the dielectric drum.

Further, since the power supply contact pieces 12-1 and 12-2 on the power supply circuit boards 13-1 and 13-2 are arranged so as to sandwich the electrostatic recording head from both sides, the construction of the first embodiment. In contrast to, the contact pressure of the contact piece acts on the head substrate as a compressive force instead of a bending force.
The required strength of the substrate itself can be reduced. Next, a third embodiment of the electrostatic recording head according to the present invention is shown in FIGS.

In this embodiment, the method of connecting the discharge member and the terminal member is different from that in the first and second embodiments. 5 and 6, the pair of terminal members 19-1 and 19-2 are composed of a plurality of conductors formed on the insulating base material 20 provided on both outer surfaces of the inverted U-shaped base body 21. Connection terminal pattern 22-
1, 22-2, ... (See FIG. 6), respectively.
Each of these connection terminal patterns extends beyond the upper edge of the base material 20, the tip end portion of which is bent in a substantially right-angled direction, and the connection portion 7-1 of the discharge member 2 provided on the upper surface of the base 21. 7
A fusion-bonded portion with -2, ... Is formed. And the connection part 7
-1, 7-2, ... and connection terminals 22-1, 22-2, ...
Solder plating is applied to the fusion-bonding portion formed on the above-mentioned tip portion so that they can be fused by heat after they are superposed. At the time of assembly, as shown in FIG. 6, the terminal members 19-1 and 19-2 are arranged so that the fused portions of the terminal members 19-1 and 19-2 overlap the corresponding connecting portions 7-1, 7-2, ... After positioning in the direction (C direction) and further moving in the up and down direction (D direction) to assemble so that the fused portions overlap, the fused portions are heated to bond the discharge electrodes and the connection terminals.

In the structure shown in this embodiment, the wire bonding method is used instead of the wire bonding method for the connection between the electrode and the connection terminal, so that the discharge member and the terminal member can be easily connected. On the other hand, since the connection terminals 22-1, 22-2, ... Are formed of thin plate-shaped conductors, the discharge electrodes are not affected by the deformation of the terminal member due to the contact pressure of power supply.

[0025]

As described above, according to the electrostatic recording head of the present invention, the discharge member for emitting ions and the terminal member for connecting the discharge member and the power supply circuit for driving the discharge member are provided. Since the above is supported by the base body as another structure, the deformation of the terminal member portion caused by the contact pressure for connection does not extend to the discharge member, and the deformation, peeling, or displacement of the laminate constituting the discharge member is prevented. Therefore, the electrostatic recording head can be stably used for a long period of time.

Further, by arranging the installation surface of the terminal member so as to intersect with the installation surface of the discharge member, the size of the electrostatic recording head itself and the installation area including the power supply circuit board can be reduced, and an image is formed. It is possible to manufacture the device in a small size.

Furthermore, since the discharge member and the terminal member are formed as separate structures, they can be positioned independently when they are installed on the base, and the electrostatic recording head can be easily assembled. Such an effect can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an electrostatic recording head according to a first embodiment of the invention.

FIG. 2 is an electrostatic recording head according to the first embodiment shown in FIG.
The side view seen from the A direction.

FIG. 3 is a perspective view showing an electrostatic recording head according to a second embodiment of the invention.

FIG. 4 is an electrostatic recording head according to the second embodiment shown in FIG.
The side view seen from the B direction.

FIG. 5 is a perspective view showing an electrostatic recording head according to a third embodiment of the invention.

FIG. 6 is a partially enlarged perspective view showing an electrostatic recording head according to the third embodiment.

[Explanation of symbols]

1 ... Base (substrate), 2 ... Induction electrode, 3 (3-1, 3-2
...) ... Discharge electrode, 4 ... Control member, 5 ... Dielectric layer, 9-
1, 9-2 ... Terminal member, 10-1, 10-2 ... Conductor wire.

Claims (2)

[Claims] 1. An electrostatic recording head comprising: an ion discharge discharge member; a terminal member for connecting the discharge member to a driving power source for the discharge member; and a base body supporting the discharge member and the terminal member. The electrostatic recording head is characterized in that the terminal member is supported by the base member in the vicinity of the discharge member as a structure separate from the discharge member and is connected to the discharge member by an electrical connection means. .. 2. The base body comprises one surface for supporting the discharge member on the upper side and another surface for intersecting the one surface and supporting the terminal member on the other side. Electrostatic recording head.