JPH05124251A - Control grid - Google Patents

Abstract

PURPOSE:To obtain a control grid which can form a print dot with good accuracy and high resolution by forming facing side of each toner carrier on two sides facing each other through a toner through hole except a crossing position in a loop electrode and two sides facing each other of another loop electrode in approximately the same plane. CONSTITUTION:Bonding together of loop electrodes 11 and 21 formed respectively on an upper pattern and a lower pattern is performed while heat setting resins with which the loop electrodes 11 and 21 are covered are melted and cured. In the formed control grid, the upper face of two sides 11A of the loop electrode corresponding to a toner through hole 3a coincides with the upper face of two sides 21A of the other loop electrode and the loop electrode of the upper pattern and the loop electrode of the lower pattern are positioned up and down through an insulation layer at the crossing positions 11B and 21B to be able to obtain a sufficient thickness for the insulation layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control grid which is arranged between a toner carrier for forming a developing electric field and a back electrode and has a group of electromagnetically openable and closable toner passage holes arranged in a matrix. In particular, the present invention relates to an image forming apparatus in which a toner image can be directly attached to a recording material such as plain paper without using a photosensitive drum or other latent image carrier by utilizing the control grid.

[0002]

2. Description of the Related Art Image formation in which toner carried on a developing roller is directly transferred onto a recording material in a dot pattern corresponding to image information without using a photosensitive drum functioning as a latent image carrier has hitherto been performed. The device is Japanese Unexamined Patent Publication No. 3-168766.
To 70 etc., and briefly describes such a device configuration based on the schematic view shown in FIG. 6, a toner carrier 1 including a sleeve-shaped developing roller electromagnetically holding toner in a thin film shape; A matrix-shaped control grid 3 is arranged between the toner carrier 1 and a back electrode 2 arranged to face the toner carrier 1.
By controlling the energization of the control grid 3 in the X-Y axis directions, the developing electric field acting on the toner passage holes 3a between the matrices is selectively cut off or made conductive in correspondence with image information. On the recording paper 4 arranged on the surface of the back electrode 2, the toner corresponding to the image information can be transferred through the toner passage hole 3a in the control grid 3, and as shown in FIG. A matrix composed of a plurality of first loop electrodes 3 extending in a slit shape in the main scanning direction (X) and a plurality of second loop electrodes extending in parallel at a predetermined angle with respect to the line. And a toner passage hole 3a is formed in each of the matrix-shaped spaces surrounded by the first loop electrode and the second loop electrode.

The control grid 3 energizes the first loop electrode sequentially with a time lag corresponding to the insertion speed of the recording paper 4, so that the dot-shaped print pattern 30 passing through the passage hole 3a is 1 as a result. In rows,
As a result, it is possible to form a dense dot pattern without particularly narrowing the width of the second loop electrode, that is, the interval between the toner passing holes in the main scanning direction.

[0004]

Therefore, according to such a basic technique, for example, as shown in FIG. 8, a control voltage is individually applied to the first loop electrode and the second loop electrode forming the control grid. Since it is necessary to apply and control electromagnetically opening and closing the toner passage hole, an insulating layer 9 is interposed between the both loop electrodes, and wirings for forming respective loop electrodes on the upper and lower surfaces of the insulating layer 9 are formed. The patterns are integrally bonded, and the surfaces thereof are formed by insulating coating. With this structure, if the control voltage levels applied to both the loop electrodes are set to the same level, the respective loop electrodes 11 are formed. , 21 and the developing roller are different from each other, the potential gradient between the developing roller 1 and the developing roller 1 is different in proportion to the difference in distance between the two loop electrodes.
Since the gap between the developing roller 1 and the developing roller 1 is an extremely thin layer of about 0.2 mm, the insulating layer 9 between the loop electrodes 11 and 21 is formed.
Is thicker, the potential gradient difference becomes so large that it cannot be ignored. Therefore, in order to maintain the potential gradient between the developing roller 1 and the developing roller 1 constant, the respective loop electrodes 11 are proportional to the distance. , 21 is required to be adjusted, which leads to a complicated circuit configuration and an increase in size of the device.

When the voltage difference between the loop electrodes 11 and 21 becomes too large to be ignored, the voltage difference causes
A reverse electric field is generated between the loop electrodes 11 and 21, and the reverse electric field may act in a direction to prevent passage of toner, or may adversely affect other adjacent through holes. If the insulating layer 9 is set to be extremely thin in order to solve such a drawback, not only the dielectric strength and the like become uncertain, but also leakage may occur.

In view of the drawbacks of the prior art, the present invention sets the control voltage of the loop electrodes arranged on the upper and lower sides of the insulating layer to the same voltage level even when the thickness of the insulating layer is increased. Even in such a case, it is an object of the present invention to provide a control grid capable of generating an accurate and high-resolution printing dot without changing the potential gradient between the developing roller and the developing roller.

[0007]

According to the present invention, at least the intersecting portions are arranged on both upper and lower sides of the insulating layer with an insulating layer interposed therebetween, and one loop electrode is formed relative to another loop electrode with respect to a plane projection plane. The present invention is applied to a control grid having first and second loop electrode groups extending in the intersecting direction and a toner passage hole group opened in each intersecting space of the both loop electrode groups. .. That is, the present invention is not limited to the FPC that forms a wiring pattern on the entire upper and lower surfaces of the insulating layer via the insulating layer and the control grid formed by the etching process described in the examples below, as well as interposing the insulating layer only on the intersection portion. The present invention is also applicable to a control grid including wire electrodes formed in a mesh shape by plain weaving in which loop electrodes are located on both upper and lower surfaces thereof.

Further, in the present invention, among the respective loop electrodes, excluding the crossing portion between the both loop electrodes, the two sides of the toner carrier facing each other through the toner passage holes and the other loop electrodes are provided. It is characterized in that the two facing sides and the facing side are set on substantially the same plane. And such a method of forming a loop electrode is such that two corresponding sides of the loop electrode are raised in a rectangular shape by press working, or an appropriate portion on the upper surface of the loop electrode corresponding to the intersecting portion is abraded by etching treatment. Alternatively, the control grid may be formed by intersecting another loop electrode with the cut portion through an insulating layer.

[0009]

According to such a technical means, since all the four sides located around the toner passage hole can be set to the same distance with respect to the developing roller 1, they are applied to the loop electrodes 11 and 21 as in the prior art. It is not necessary to change the control voltage to be used, and as a result, the circuit configuration can be simplified and downsized. In addition, the fact that there is no difference in the control voltage between the loop electrodes 11 and 21 does not cause a reverse electric field between the loop electrodes 11 and 21, which means that the image caused by the reverse electric field is Disturbances and adverse effects can be prevented, which enables accurate and high-resolution printing dot generation. Further, according to the present invention, it is not necessary to set the intersecting portion between the both loop electrodes to be flush with each other. In other words, a step for forming a thick insulating layer can be provided between the both loop electrodes. ,
This makes it possible to prevent a sufficient dielectric strength and the risk of leakage.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described in detail below as an example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Not too much. Figure 3
Is a control grid manufactured according to the present invention, and FIGS. 4 and 5 show upper and lower wiring patterns for manufacturing the control grid. Next, the structure of the control grid will be described according to the manufacturing procedure. FIG. 4 is a lower pattern 20 having a traverse loop electrode 21 extending in the main scanning direction, and FIG. 5 is a print extending in a direction slightly tilted upward with respect to the direction in which the recording paper is conveyed (sub-scanning direction). Loop electrode 1
The upper pattern 10 having the number 1 is formed by etching the copper foil.

Next, the shape of each pattern will be described in detail. The lower pattern 20 has a strip shape having a length slightly larger than the axial length of the developing roller 1 and extending long in the main scanning direction, and the left and right sides in the longitudinal direction are etched into a rectangular shape to form a space area 22. At the same time, eight loop electrodes 21 extending in parallel in a predetermined direction with a small pitch are provided in the central portion sandwiched by the space regions 22, and the loop electrodes 21 are arranged along the longitudinal center line of each loop electrode 21. Leader wires 23A and 23B extending to both ends are formed, and the leader wires 23A and 2B are formed.
Square lands 24A, 24 for receiving signals are provided on both ends of 3B.
B is formed, and horseshoe-shaped marks 26 for aligning with the upper pattern 10 are formed on both right and left sides in the lateral direction of the land portions 24A and 24B formation areas.

On the other hand, the upper pattern 10 shown in FIG. 5 has a band-like rectangular shape which is substantially the same as the lower pattern 20, and the left and right sides in the lateral direction thereof are etched into a rectangular shape to form a space portion 12 and at the same time in the space area. 300 loop electrodes 11 extending parallel to each other at a small pitch at small pitch intervals in a direction slightly inclined with respect to the lateral direction, and along the center line of each loop electrode 11 Leader lines 13A and 13B extending to both end sides are formed, a signal receiving land portion 14A is formed on one end side of the lead wire lines 13A and 13B, and a circular land portion 14B for pattern inspection is formed on the other end side. At the same time, the circular marks 15 are set to have the same diameter as the horseshoe-shaped mark 25 in order to align the horseshoe-shaped mark 25 of the lower pattern 20 on the left and right sides in the longitudinal direction of the loop electrode formation region. To the opening. Reference numerals 18 and 28 are guide holes for positioning the pattern.

The upper and lower patterns 10 and 20 formed as described above are shown in FIG. 1 with the loop electrodes 11 and 21 held in position using the guide holes 18 and 28, respectively.
When the control grid is formed as shown in (A), the two sides 11A and 21A facing each other around each toner passage hole 3a are pressed so as to have a rectangular shape. Note that 11B and 21B are intersections. In this case, the protruding height of the two sides 11A of the lower pattern loop electrode 11 is set to be larger than the protruding height of the upper pattern loop electrode 21, and the upper surface thereof is set to be flush. Alternatively, only the loop electrodes 11 and 21 of the lower pattern 20 may be formed to be convex as shown in (B) without pressing the loop electrodes 11 and 21 of both the upper and lower patterns.

Further, instead of the press working, after forming the wiring patterns 10 and 20 with a thick body foil as shown in FIG. 2A, the loop electrodes 11 and 21 corresponding to the intersecting portions are formed.
When the control grid 3 is formed by cutting the upper surface into a rectangular shape by etching and crossing the cut portions 11B and 21B with the other loop electrodes 11 and 21 via the insulating layer 31 as described later. The upper surfaces of the two sides 11A and 21A of each loop electrode located around each toner passage hole 3a are flush with each other. Of course, in this case as well, the upper pattern loop electrode 11 is set thin as shown in (B) without etching the upper and lower pattern loop electrodes 11 and 21 as shown in (A). Two
1 is formed into a thick wall and then the crossing portion 11 is formed by etching.
B and 21B may be formed in a rectangular shape.

In the patterns 10 and 20 in which the loop electrodes 11 and 21 are formed in the rectangular wave shape as described above, after masking the land portions 14A, 14B, 24A and 24B, glass epoxy resin or polyimide amide resin or the like is used. An insulating thermosetting resin is applied and pre-dried, and this is repeated several times to perform an insulating film treatment of a predetermined film thickness. Next, after aligning the horseshoe-shaped mark 25 formed in each of the upper and lower patterns 10 and 20 with the circular mark 15 having the same diameter as the mark 25 for alignment, heat is applied to the loop electrode formation region. By press-contacting the loop electrodes 11 and 21, the thermosetting resin coated on the loop electrodes 11 and 21 is melted and cured, and the loop electrodes 11 and 21 formed on the upper and lower patterns 10 and 20 are joined to each other.

In the control grid 3 formed as described above, as shown in FIGS. 1 and 2, the upper surface of the loop electrode two sides 11A corresponding to the toner passage holes 3a is the upper surface of the other loop electrode two sides 21A. Matches and intersects 11
As shown in FIGS. 1 (C) and 2 (C) on B and 21B, the upper pattern loop electrode and the lower pattern loop electrode are located above and below the insulating layer 31, and a sufficient insulating layer 3 is formed.
A wall thickness of 1 can be obtained. Then, returning to the original state, after the joining, the masking of the land portion is removed in the above step, and a predetermined pattern inspection is performed using the land portion.
As shown in, the housing 1 is cut off from the part indicated by the imaginary line.
After disconnecting the loop electrodes 11 and 21 and the lead wires 13 and 23 connected to the loop electrodes 11 and 21 from 9, 29, control is performed by connecting to the IC substrate or the like through the signal receiving lands 14A, 14B, 24A and 24B. The grid is completed.

[0017]

As described above, according to the present invention, even when the thickness of the insulating layer is increased, in other words, the control voltage of the loop electrodes arranged on the upper and lower sides of the insulating layer is set to the same voltage level. Even in this case, the potential gradient between the developing roller and the developing roller does not fluctuate, so that it is possible to provide a control grid capable of generating highly accurate print dots with high resolution. And so on.

[Brief description of drawings]

1A, 1B, and 1C show the shape of a loop electrode and its cross-sectional structure according to an embodiment of the present invention.

2 (A), (B) and (C) show the shape of a loop electrode and its cross-sectional structure according to an embodiment of the present invention.

FIG. 3 is a completed view of a control grid according to an embodiment of the present invention.

FIG. 4 shows one wiring pattern for manufacturing the control grid of FIG.

5 shows another wiring pattern for manufacturing the control grid of FIG.

FIG. 6 is an overall configuration diagram showing a basic technique to which the present invention is applied.

FIG. 7 is a schematic diagram showing an arrangement state of the α-Y axis loop electrodes of the control grid.

8 is a schematic diagram showing a cross section of a control grid with the apparatus of FIG.

[Explanation of symbols]

 1 Toner Carrier 2 Back Electrode 3 Control Grid 10, 20 Wiring Pattern 11, 21 Loop Electrode 11A, 21B Two Sides 11B, 21B Crossing Site 3a Pass Hole

Claims (1)

[Claims] 1. A control grid in which a group of toner passage holes that are electromagnetically openable and closable are interposed between a toner carrier that forms a developing electric field and a back electrode, and one loop electrode is connected to the other. A first and a second loop electrode group extending in a direction intersecting the plane projection plane with respect to the loop electrode, and a toner passage hole group opened in each crossing space of the both loop electrode groups. At least the crossing portions of the first and second loop electrodes are arranged on both upper and lower sides of the insulating layer via an insulating layer,
Of the respective loop electrodes, the two sides facing each other through the toner passage hole and the two facing sides of the other loop electrodes, excluding the intersecting portion, are respectively located on substantially the same plane. Control grid characterized by being formed