JP2001198945A - Method and mold for insert molding and electrophotographic developing blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insert molding method capable of ensuring a necessary value in the degree of parallelization of an insert member and a molding part. SOLUTION: In an insert molding method for inserting an insert member 101 in molds 1, 2 to perform molding, a preforming process for holding the insert member in such a state that processing edges are left in the holding parts 14, 16 of the insert member 101 to perform preparatory insert molding, a correction processing process for performing the correction processing of the holding parts 14, 16 on the basis of the accuracy of the preformed article molded in the preforming process and a final molding process for holding the insert member by the holding parts corrected in the correction processing process to perform final molding are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insert molding method for inserting an insert member into a mold and then performing injection molding, a mold for molding, and a developing blade for electrophotography molded with the mold.

[0002]

2. Description of the Related Art Conventionally, an insert member is formed by fitting a positioning pin or a positioning hole provided in a mold cavity with a hole or a pin of the insert member.
Positioned and fixed in the mold. When parallelism is required between the plane of the insert member and the longitudinal axis of the resin or rubber molded part, the mold is usually arranged so that the plane of the insert member is parallel to the cavity longitudinal axis of the resin or rubber molded part. The height and positioning accuracy of the positioning pin or positioning hole of the insert member provided on the insert member are increased, and the insert molded product is parallelized.

[0003]

As an example of the prior art,
Insert member 101 (for example, sheet metal) as shown in FIG.
Is placed in the mold of FIG. 5 and injection molding of, for example, a developing blade for electrophotography is considered. Here, for a developing blade for electrophotography, a flat portion (B in FIG. 4) of a sheet metal and a tip (line A in FIG. 4) of a forming portion (a portion shown by a broken line in FIG. 4) which are mounting references. The parallelism is the precision required to uniformly distribute the toner on the developing sleeve. If the parallelism between the sheet metal flat portion B and the portion A is broken, uneven toner thickness distribution occurs in the longitudinal direction. ,
Density unevenness occurs in the resulting electrophotograph. Here, 112
Is a gate, but if a gate is provided directly in the molded product part, wasteful material is not consumed as compared with the case where a gate is provided outside the molded product, and material costs can be reduced. However, on the other hand, since the gate position is close to the tip of the resin or rubber molded part that requires precision, the resin or rubber molded part is deformed due to residual stress inside the resin or rubber caused by injection pressure or injection speed etc. In some cases, a problem arises in that the tip of the resin or rubber molded portion does not have the required parallelism with respect to the plane of the sheet metal as the insert member (see FIG. 6).

Here, as shown in FIG. 4, the insert member 101 is a sheet metal bent into an L-shape by press working. Reference numerals 102a and 102b denote positioning holes for the die, which are formed in the insert member 101 by press working.
The positioning pins 213a and 213b of the mold enter the positioning holes 102a and 102b, and are held in the mold. Reference numeral 103 denotes a molding part in which a resin or rubber is molded by a mold to become a blade.

Although it is possible to improve the degree of parallelism of A to B to some extent by molding conditions, a correction method by molding conditions is a method of narrowing the degree of freedom of production, that is, for example, wrinkles or bubbles on the resin surface. , Etc.,
There is a possibility that the non-defective rate will deteriorate.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an insert molding method and a molding die capable of securing a required degree of parallelism between an insert member and a molded portion. And a developing blade for electrophotography.

[0007]

Means for Solving the Problems To solve the above-mentioned problems,
In order to achieve the object, an insert molding method according to the present invention is characterized in that in an insert molding method in which an insert member is inserted into a mold to perform molding, a machining allowance is left in a holding portion for holding the insert member. A preforming step of holding the insert member and performing preliminary insert molding, and a correction processing step of performing correction processing of the holding portion based on the accuracy of the preformed product formed in the preforming step; A main forming step of holding the insert member by the holding portion corrected in the correction processing step and performing main forming.

Further, in the insert molding method according to the present invention, in the correction processing step, the holding portion may be corrected based on the accuracy of the preform so that the insert part can be tilted and held. Features.

Further, the molding die according to the present invention is a molding die used for insert molding in which an insert member is inserted into a mold to perform molding. A holding member disposed on the fixed mold member and the movable mold member for holding the insert member, wherein the holding member has a correction allowance.

[0010] In the molding die according to the present invention, the holding member may be kept in a state where the compensation allowance is left.
It is characterized in that the insert member is held, preliminary insert molding is performed, and correction processing is performed based on the accuracy of the preform formed by the preliminary insert molding.

Further, an electrophotographic developing blade according to the present invention is characterized in that it is formed by the insert molding method described above.

[0012] An electrophotographic developing blade according to the present invention is characterized by being formed by the insert molding method described above.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. Before that, an outline of the present invention will be described.

According to the present invention, the sheet metal as the insert member is provided at a certain angle with respect to the cavity forming the tip of the resin or rubber molded portion in the mold, that is, with an offset at a certain angle, and is mounted obliquely. By doing so, even if the molded portion is deformed, the parallelism between the reference surface of the sheet metal as the insert member and the distal end of the molded portion can be minimized.

Hereinafter, an embodiment in which the present invention is applied to molding of a developing blade for electrophotography will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a mold and an insert member in a state in which a mold is opened.

In FIG. 1, reference numeral 1 denotes a fixed die, and 2 denotes a movable die, both of which are fixed to a platen of a molding machine (not shown). You can move until it occurs.

Reference numeral 101 denotes an insert member used in the insert molding, which is the same as the sheet metal member already described with reference to FIG.

FIG. 1 shows an open state where the movable mold 2 is not closed. 102a and 102b are positioning holes formed in the insert member 101. 13
Reference numerals a and 13b denote positioning pins installed on the movable mold 2 for positioning the insert member 101. The insert member 101 has positioning holes 102a, 102b.
By fitting the positioning pins 13a and 13b with the positioning pins 13a and 13b, the positioning is performed at a predetermined position in the movable mold 2. 10,
Reference numeral 11 denotes a fixed side cavity and a movable side cavity into which actual resin and the like are injected, respectively. Reference numeral 12 denotes a gate disposed on the fixed mold side to which a resin or the like is injected. In the electrophotographic developing blade, molding is performed by injecting liquid silicone rubber from the gate 12 between the fixed side cavity 10 and the movable side cavity 11.

B is a reference for mounting the developing blade.
This is a surface serving as a measurement reference surface of the insert member 101.

Reference numeral 14 denotes a reference plane B of the insert member 101.
This is a sheet metal reference piece that is in contact with and serves as a reference on the mold side.

Reference numeral 16 indicates that even if the thickness of the insert member 101 varies, the insert member 101 is moved up and down so as to prevent burrs from appearing on the reference plane B of the insert member 101, thereby absorbing variations in thickness. It is a sheet metal presser piece pressed against the side. A hole 16 a for allowing the positioning pin 13 to escape is formed in the sheet metal holding piece 16. 1
5 pushes up the sheet metal holding piece 16 and inserts the insert member 10
1 is a spring that presses the fixed mold 1 against the fixed mold 1 to prevent molding burrs from appearing.

The insert member 101 is a vacuum suction device (not shown) or a magnet provided on the movable
Has been adsorbed. This is to prevent the insert member 101 from dropping from the movable mold 2 even when the fixed mold 1 and the movable mold 2 are clamped in the horizontal mold.

FIG. 2 is a sectional view of the fixed mold 1, the movable mold 2, and the insert member 101 in a state where the movable mold 2 is closed and the mold is clamped.

FIG. 3 is a view of the movable mold 2 from the fixed mold side when the fixed mold 1 and the movable mold 2 are clamped in the state of FIG. The insert member 101 is provided with positioning holes 10a and 13b provided on the movable mold 2 respectively.
The movable mold 2 is positioned at a predetermined position by fitting the 2a and 102b.

In FIG. 1, the fixed sheet metal reference piece 14 is provided with a sufficient margin for additional machining in advance. That is, the surface C of the insert member 101 that is in contact with the reference surface B is
Although it is made parallel to the corner line D forming the front end line A of the cavity forming portion, it is made high so that the correction dimension amount can be ground in a later step.

The sheet metal presser piece 16 in the movable mold 2 is
In order to stabilize the inside of the mold with the insert member 101 interposed therebetween, the spring 15 is provided on the side opposite to the contact with the insert member 101. The upper surface of the sheet metal holding piece 16 is also formed in parallel with the corner line D forming the front end line A of the cavity forming portion. However, similar to the sheet metal reference piece 14, sufficient additional processing correction is performed so that additional processing can be performed later. They have a teenage and are expensive. The stroke of the spring 15 has a stroke enough to hold the insert member 101 therebetween even when the sheet metal reference piece 14 and the sheet metal holding piece 16 both have a sufficient additional machining allowance.

In this state, the insert member 101 is mounted in the mold while being pushed further into the movable mold 2 by the correction allowance of the sheet metal reference piece 14. At that time, the spring 15
Is a state in which the correction allowance of the sheet metal reference piece 14 and the correction allowance of the sheet metal holding piece 16 are more deflected.

In this state, molding is performed once, and the longitudinal position of the tip A of the silicone rubber molded portion with respect to the reference plane B of the insert member 101 is measured to clarify the influence of the gate. As a result, a graph of the longitudinal position of the tip A of the silicone rubber molded portion from the insert member reference plane B as shown in FIG. 7 is obtained. Here, since a correction margin is left on the upper surface of the sheet metal holding piece 16, the distance from the insert member reference plane B to the tip end A of the molded portion becomes smaller as a whole than the graph shown in FIG.

From the graph of FIG. 7, oblique parallel tangents 21a and 21b are drawn to minimize the fluctuation width of the distance from the insert member reference plane B to the tip end A of the molded portion, and the offset correction amount a And the amount of inclination b of the insert member 101 for minimizing the required parallelism
(= Slope b / L).

The mold is disassembled, and the sheet metal reference piece 1 of the fixed mold 1 is disassembled.
Then, the offset correction amount a and the inclination amount b are ground from the surface C by a grinder or the like, and are shifted obliquely (inclination b / L).

Similarly, the upper surface of the sheet metal holding piece 16 of the movable mold 2 is ground so as to have a tilt amount b (tilt b / L).

Thereafter, by assembling the fixed mold 1 and the movable mold 2 as before, the insert member 101 can be mounted so that the mold has a certain angle (inclination b / L).

The parallelism of the tip A of the silicone rubber molded portion with respect to the reference surface of the insert member 101 can be minimized as shown in FIG. it can.

As described above, according to this embodiment, in the insert molding apparatus and the molding method for mounting the insert member 101 in the mold and then performing injection molding, the insert member is filled with the silicone rubber in the mold. It can be mounted with a certain angle (inclination b / L) with respect to the cavity shape. Thereby, in the prior art, since the gate position is close to the silicone rubber molding tip requiring accuracy, the silicone rubber molded part is deformed by the residual stress inside the silicone rubber caused by the injection pressure or the injection speed, etc. Although the predetermined parallelism could not be achieved with respect to the reference plane of the sheet metal whose silicone rubber molding tip is the insert member, the parallelism was minimized and the predetermined parallelism was reduced without narrowing the non-defective molding conditions. It is possible to satisfy.

FIG. 9 shows a developing blade 104 used for electrophotography, which is insert-molded by the method of the present embodiment. In FIG. 9, reference numeral 201 denotes a photosensitive drum, and the photosensitive drum 201 exposes image information such as characters, drawings, and symbols on a document on a document table (not shown) or image information by a laser scanner by an exposure unit.

The image information exposed on the photosensitive drum 201 is developed on a photosensitive drum by a developing cylinder 202 of a developing unit, and is transferred onto a copy sheet. The toner on the copy sheet is fixed by a fixing unit. The copying process is performed.

In the above-described developing step, the amount of toner (toner thickness) placed on the developing cylinder is determined by the positional relationship between the rubber portion 103 of the toner amount adjusting member 104 called a developing blade and the developing cylinder 202. The amount of toner on the drum has been adjusted.

Therefore, when the parallelism of the tip of the silicone rubber molding portion with respect to the reference plane of the insert member, which is the position reference of the developing blade 104, is not satisfied, the developing cylinder and the tip of the silicone rubber molding portion which determine the toner thickness are not satisfied. = Because the parallelism of the rubber part 103 is not satisfied,
The amount of toner (toner thickness) placed on the developing cylinder is not uniform in the longitudinal direction of the developing blade, and the thickness is uneven. As a result, defects such as uneven density appear in the image on the copy paper.

However, according to the present embodiment, in the prior art, since the gate position is close to the tip of the molded silicone rubber which requires precision, the residual stress inside the silicone rubber caused by the injection pressure or the injection speed, etc. ,
The silicone rubber molded part is deformed, and the silicone rubber molded tip does not achieve the predetermined parallelism with respect to the reference plane of the sheet metal as the insert member, but the parallelism is minimized and the predetermined parallelism is reduced. It became possible to satisfy. This makes it possible to uniformly adjust the amount of toner (toner thickness) placed on the developing cylinder, and as a result, it is possible to prevent a problem such as density unevenness from appearing on an image on copy paper.

As described above, according to the present embodiment, when the insert member is mounted in the mold, the amount of deformation of the resin or rubber portion to be molded is anticipated, and the insert member in the mold is moved in the mold. In the prior art, by mounting the resin or rubber at a certain angle with respect to the cavity shape into which the resin or rubber is injected, the tip of the resin or rubber molding portion is influenced by the position of the gate with respect to the insert member reference plane, The slant between the gate and the anti-gate portion, which could not satisfy the predetermined parallelism, minimized the parallelism without executing special difficult molding conditions and reduced the predetermined parallelism. It is possible to satisfy.

Further, by using these means,
It is possible to provide an electrophotographic developing blade in which the resin or rubber tip of the insert member at the time of molding minimizes the parallelism with respect to the reference plane of the insert member.

[0043]

As described above, according to the present invention,
The parallelism between the insert member and the molded portion can be secured to a required value.

[Brief description of the drawings]

FIG. 1 is a sectional side view of a mold according to an embodiment (when the mold is opened).

FIG. 2 is a sectional side view of a mold according to one embodiment (when the mold is closed).

FIG. 3 is a plan view of a movable mold according to an embodiment.

FIG. 4 is a view showing an insert member.

FIG. 5 is a view showing a conventional molding method.

FIG. 6 is a diagram showing a tip position of a forming portion with respect to an insert reference surface in a conventional forming method.

FIG. 7 is a diagram showing the position of the tip of the molded portion with respect to the insert reference plane (before correction).

FIG. 8 is a diagram showing the tip position of the molded portion with respect to the insert reference plane (after correction).

FIG. 9 is a diagram illustrating the configuration of an image forming apparatus.

[Explanation of symbols]

 Reference Signs List 1 fixed mold 2 movable mold 10 fixed cavity 11 movable cavity 12 gate 13a, 13b positioning pin 14 sheet metal reference piece 16 sheet metal holding piece 101 insert member 102a, 102b positioning hole 103 molded rubber part 104 developing blade 201 photosensitive drum 202 Developing cylinder

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Masahiro Watanabe 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kenichi Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Kentaro Niwano 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) 2H077 AD06 AD13 FA22 4F202 AA33L AA45 AC06 AD18 AD23 AH33 AH81 AP06 AR07 AR20 CA11 CB11 CK42 CQ01 CQ07 4F206 AA33L AA45 AC06 AD18 AD23 AH33 AH81 AP06 AR07 AR20 JA07 JB12 JF05 JL09 JP11 JQ81

Claims (6)

[Claims] 1. An insert molding method for performing molding by inserting an insert member into a mold, wherein the insert member is held in a state in which a machining allowance is left in a holding portion for holding the insert member, and a spare insert is provided. A preforming step of performing molding, a correction processing step of performing a correction processing of the holding section based on the accuracy of the preformed product formed in the preforming step, and a holding section corrected in the correction processing step. A main molding step of holding the insert member and performing main molding. 2. The insert molding method according to claim 1, wherein in the correction processing step, the holding portion is corrected based on the accuracy of the preformed product so that the insert component can be tilted and held. 3. A molding die used for insert molding in which an insert member is inserted into a mold to perform molding, wherein: a fixed mold member, a movable mold member, the fixed mold member and the movable mold member. And a holding member for holding the insert member, wherein the holding member has a correction allowance. 4. The holding member holds the insert member while performing the correction machining allowance, performs preliminary insert molding, and performs the preliminary insert molding based on the accuracy of the preliminary molded product formed by the preliminary insert molding. The molding die according to claim 3, wherein the molding die is subjected to correction processing. 5. An electrophotographic developing blade formed by the insert molding method according to claim 1 or 2. 6. An electrophotographic developing blade formed by the insert molding method according to claim 3. Description: