JPH09319206A - Sensor fixing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of fixing parts and attaching operation manhours and to reduce the attaching cost of a sensor by engaging the lug of a sensor attaching member with lug provided in a container thereby fixing sensor to the sensor attaching member. SOLUTION: The lugs 1 are provided in two places in the container 56 and a developer tank 52 as the sensor attaching member is provided with the lugs 10 and a hole into which a detecting part 50a is inserted, in the abutting positions of the lugs 1. Then, the lugs 1 and 10 are engaged with each other to fix the toner sensor 50 to the developer tank 52. In such a case, when the lugs 1 and 10 have chamfers 1a and 10a, they are easily engaged with each other. The number of the lugs 1 and 10 can be increased/decreased according to the side of the sensor. When the lugs 1 are opened, the sensor can be removed. But when projecting parts are provided in the vicinities of the top ends of the lugs 1, the lugs 1 can easily be opened. Thus, the sensor can be fixed to the sensor attaching member with one operation without using a fastening part, so that the number of parts can be reduced and also the number of the attaching operation manhours can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor composed of a detection circuit and a container for accommodating this circuit, and more particularly to a toner density or residual amount (or presence / absence of toner) in a developer used in a copying machine or a printer. The present invention relates to a toner sensor for detecting.

[0002]

2. Description of the Related Art Various toner sensors have been widely used in copying machines, printers and the like. These known toner sensors include, for example, a method of detecting the toner concentration in a two-component developer composed of a magnetic carrier and toner, and a method of detecting the remaining amount of magnetic toner or the presence or absence of magnetic toner. A differential transformer type toner sensor is often used.

FIG. 6 is a sectional view of a developing device of a copying machine.
In FIG. 6, a developer 5 including a magnetic carrier and toner
1 is accommodated in a developer tank 52, and a developing roller 55 is arranged inside the developer tank 52 so as to face the photosensitive drum 58 rotating in the arrow Z direction. The developing roller 55 includes a cylindrical non-magnetic sleeve 55a that rotates in the direction of arrow X and a permanent magnet 55b that has a plurality of magnetic poles (three in the figure) on the surface and is fixedly arranged. The non-magnetic sleeve 55a regulates the thickness of the retained developer 51 by the doctor member 59 and conveys it to the surface of the photoconductor drum 58, and develops the electrostatic latent image carried on the photoconductor drum 58 with toner. The toner image is transferred to a transfer material such as plain paper and undergoes a fixing process to form a final image (not shown). Since only the toner is consumed during the development, the toner concentration in the developer decreases.
The toner concentration is detected by the toner sensor 50. When the output of the toner sensor 50 is smaller than the reference value, the toner replenishing roll 54 is rotated to replenish the toner 51a. The replenished toner is uniformly stirred in the developer by the stirring paddle 53. When the output of the toner sensor becomes larger than the reference value, the rotation of the toner supply roll is stopped and the toner supply is stopped. In this way, the toner concentration in the developer is kept within a certain range.

A conventional method for fixing the sensor will be described with reference to FIG. The same members as those in FIG. 6 are designated by the same reference numerals.
(A) is a toner sensor 50 fixed by a screw 60.
FIG. (B) is a plan view of (a). A screw hole is provided at a predetermined position of the developer tank 52 and a detection portion 50a of the sensor.
There is a hole for the toner sensor, and the toner sensor has a hole for the screw to pass through. If the size is about several tens of mm like a toner sensor, screwing may be performed at two places. (C) is a sectional view of the sensor fixed by an E-shaped retaining ring 61.
(D) is a top view of (c). Boss 62 in the developer tank
A hole for the sensor's detection part is provided, and the toner sensor is provided with a hole for passing the boss, and the boss is fixed by caulking with an E-shaped retaining ring.

[0005]

Since the conventional toner sensor is mounted on the developer tank as described above, there is a problem that not only the number of fixed parts is large, but also the number of man-hours for mounting is large. Further, when the screw is used, there is a problem that the developer tank is scraped into chips during fastening, and the chips are mixed with the developer.

An object of the present invention is to provide a sensor fixing method which can reduce the number of fixing parts and man-hours for mounting to achieve a reduction in sensor mounting cost.

[0007]

In order to achieve the above object, in the first aspect of the present invention, there is provided a detection unit or a detection circuit including the detection unit, and a sensor including a container for accommodating the detection unit.
A technical means is employed in which at least one claw is provided on the container, and the claw of the sensor mounting member provided at the position where the claw abuts is engaged with the claw to fix the sensor to the sensor mounting member.

In the first invention, not only is a fastener such as a screw unnecessary, but also the claw of the container and the claw of the sensor mounting member can be engaged with each other with a single touch, so that the number of man-hours for mounting can be greatly reduced, and It is advantageous for cost reduction.
Further, it is possible to prevent the trouble caused by the cutting powder from the screw being mixed with the developer in the developer tank.

According to a second aspect of the invention, in a sensor comprising a detection part or a detection circuit including the detection part and a container accommodating the detection part, at least one boss or hole is provided in the container,
The technical means of fixing the sensor to the sensor mounting member by fitting the boss or hole into the hole or boss of the sensor mounting member provided at the position where the boss or hole abuts is adopted.

When the sensor container is provided with a boss, the sensor is fixed to the sensor mounting member by fitting the boss into the hole of the sensor mounting member provided at the position where the boss abuts. If the sensor container has a hole,
The sensor is fixed to the sensor mounting member by fitting the hole into the boss of the sensor mounting member provided at the position where the hole abuts. Also, when a boss and a hole are provided in the sensor container, the sensor is fixed to the sensor mounting member by fitting the boss and the hole in the sensor mounting member provided at the position where the boss and the hole abut. To do.
The holes provided in the sensor mounting member or the sensor container may be through holes or non-through holes. Further, the sensor fixing method by engaging the claw of the first invention and the sensor fixing method by fitting the boss and the hole of the second invention may be used together in one sensor. The term "fitting" as used herein means a state in which the boss and the hole are fixed by frictional force or mechanical engagement with each other.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
1 and 2 show the method of the present invention for fixing a sensor to a sensor mounting member. The sensor is a toner sensor 50, and the sensor mounting member is a developer tank 52. The container 56 of the toner sensor 50 accommodates a detection unit 50a and a detection circuit (not shown) inside.

In FIG. 1A, a claw 1 is provided at two locations on a container 56, and a claw 1 is provided on a developer tank 52 which is a sensor mounting member.
A hole into which the claw 10 and the detection unit 50a are inserted is provided at a position where the abutting contacts. Toner sensor 50 by engaging claws 1 and 10
Is fixed to the developer tank 52. At this time, if the claws 1 and 10 are chamfered 1a and 10a, they can be easily engaged. The number of nails can be increased or decreased depending on the size of the sensor. When removing the sensor, the claw 1 may be opened, but if a protrusion is provided near the tip of the claw 1, it is easy to open the sensor. In addition, the detection unit 50a
In order to prevent the developer from leaking from the hole for receiving the toner, a sheet or ring formed of an elastic member such as silicon rubber may be sandwiched between the toner sensor 50 and the developer tank 52, or a filler may be filled. .

In FIG. 1B, bosses 2 are provided at two places instead of the claws in FIG. 1A, and holes 11 for receiving the bosses 2 are provided in the developer tank instead of the claws. The toner sensor 50 is fixed to the developer tank 52 by pressing the boss 2 into the hole 11. At this time, if the boss 2 and the hole 11 are chamfered, they can be easily press-fitted. The number of bosses and holes can be increased or decreased depending on the size of the sensor.

FIG. 1 (c) shows a combination of the fixing methods of (a) and (b). In FIG. 1D, the boss and the hole are mechanically engaged with each other instead of being press-fitted. Contrary to (b), a hole is provided in the brim 4 of the toner sensor, and a boss (a size allowing a gap to the hole of the brim 4) is provided in the developer tank. After passing the boss through the hole of the brim 4, the tip of the boss is melted by heat and deformed to form the rivet-shaped tip 3, whereby the toner sensor 50 is fixed to the developer tank 52. This method is effective even when the strength of the sensor mounting member is small. Further, when removing the sensor, the rivet-shaped tip 3 must be cut, but if the boss is formed in a pipe shape, a female screw can be provided and can be fixed again with a screw. still,
The dimensions of the boss and the hole may be such that they can be press-fitted.

Similar to FIG. 1A, FIG. 2E shows the engagement by the claws, but this is a fixing method in which the claw 5 of the sensor is on the inside and the claw 12 of the developer tank is on the outside. There is an advantage that the container integrated with the claw 5 can be easily manufactured. 2 (f) is shown in FIG.
Contrary to (b), the boss 13 provided in the developer tank is pressed into the hole 6 provided in the toner sensor. FIG. 2G shows engagement by the R-shaped claws 7 and 14 each having a rounded tip.

The dimensions of the boss and the hole must be such that they can be press-fitted when they are fixed by the frictional force of each other. However, as a method for more securely fixing the sensor and improving the workability of mounting the sensor, Regarding the boss, the shape is split pin shape to have springiness, taper,
There are methods such as chamfering and rounding the corners. For holes, there are methods such as tapering, chamfering corners and rounding.
FIG. 3 shows an example. The same reference numerals as those in FIGS. 1 and 2 denote the same members. (A) is a side view of a split pin type boss 22 in which the boss has a split pin shape. (B) is a front view of (a). In FIG. 6C, the material reservoir 23 is provided in the hole 11 of the developer tank 52 in the form of a spot facing. When the boss is press-fitted into the hole 11 in the direction of the arrow, the resin material on the press-fitted surface of the boss may be squeezed and moved near the root of the boss depending on the resin material forming the boss and the load of the press-fitting. In this case, the boss cannot be pressed into the base, but this can be prevented by providing the material reservoir 23.

Next, materials for the container of the sensor and the sensor mounting member will be described. When a coil is used for the detection part of the sensor and a change in the inductance is used, it is necessary that the container and at least the sensor mounting member near the sensor are electrically insulating. In the case of conductivity, the inductance is affected by the generation of eddy currents, which is not preferable. The above-mentioned container and engaging means (claw) and / or fitting means (boss and hole), and sensor mounting member and engaging means and / or fitting means are made of resin integrally by using, for example, known injection molding means. It is preferable to mold into. ABS resin, Duracon, polybutylene terephthalate resin (PBT), 4
Known resins such as fluorinated ethylene, polyphenylene sulfide resin, polyamide resin, polyimide resin, polyamideimide resin, and polyester resin can be used. Of these, ABS resin is most suitable in terms of moldability and price.

In the above resin, one or more fillers such as glass fiber, carbon fiber, known whiskers, glass beads, known ceramic particles, etc. may be used as filler in order to improve mechanical properties, heat resistance and the like. Can be added in an amount of 10 to 50% by weight, more preferably 20 to 40% by weight, based on the weight of the resin.

FIG. 4 shows a sectional view of the toner sensor 50 fixed to the developer tank 52 by the sensor fixing method of the present invention. The claw 37a and the boss 37b are integrally formed with the container 37 to fix the toner sensor 50 to the developer tank 52. Reference numeral 30 denotes a differential transformer that is a detection unit, and mainly includes the coil bobbin 3
1 and a primary coil 32 wound around it, a detection coil 33 as a secondary coil, a reference coil 34, and a screw core 35. The screw core is for setting an output value, and is made of soft ferrite or the like and is screwed to the central shaft portion of the coil bobbin 31 so as to be movable in the axial direction of the coil bobbin. The differential transformer 30 is surface-mounted on the printed wiring board 36 together with the detection circuit by soldering the terminals of the three coils to the printed wiring board 36.

Next, as shown in FIG.
The connection between the detection coil 33, which is the next coil, and the reference coil 34, and the overall detection circuit configuration are shown. In FIG. 5A,
Reference numeral 35 is a screw core, and 38 is a developer to be detected. Further, FIG. 5B shows an example of output data with respect to time t in each part of a, b, c, d in FIG. 5A.

[0021]

According to the present invention described above, since the sensor can be fixed to the sensor mounting member with one touch without fastening parts, the number of parts can be omitted and the number of man-hours for mounting can be reduced, so that the sensor mounting cost can be reduced. A reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a sensor fixing method of the present invention.

FIG. 2 is a sectional view showing an embodiment of a sensor fixing method of the present invention.

FIG. 3A is a side view of a split pin type boss. (B)
[Fig. 3] is a front view of (a). (C) is an explanatory view of a material reservoir.

FIG. 4 is a cross-sectional view showing an example in which the sensor fixing method of the present invention is used for a toner sensor.

5A is a diagram showing an example of a detection circuit configuration in a toner sensor, and FIG. 5B is a diagram showing output characteristics of FIG. 5A.

FIG. 6 is a cross-sectional view showing a developing device in a copying machine.

FIG. 7 is a diagram showing a conventional fixing method for a toner sensor.

[Explanation of symbols]

1,5,10,12 Claws, 2,13 Boss, 6,11
Hole 50 toner sensor, 52 developer tank

Claims (6)

[Claims] 1. A detection unit or a detection circuit including the detection unit,
In a sensor including a container that stores the sensor, the container is provided with at least one claw, and the claw of the sensor mounting member provided at a position where the claw abuts is engaged with the claw to fix the sensor to the sensor mounting member. A method for fixing a sensor, which comprises: 2. A detection unit or a detection circuit including the detection unit,
In a sensor comprising a container for accommodating it, at least one boss or hole is provided in the container, and the boss or hole is fitted into the hole or boss of the sensor mounting member provided at the position where the boss or hole abuts. A method for fixing a sensor, comprising fixing the sensor to a sensor mounting member. 3. The container is provided with at least one boss or hole, and the boss or hole is fitted into the hole or boss of a sensor attachment member provided at a position where the boss or hole abuts. The sensor fixing method according to claim 1. 4. The sensor fixing method according to claim 1, wherein the claw is provided with a protruding portion, and the sensor can be removed by releasing the engagement. 5. A claw, a boss, at least one of a hole and a container are integrally molded with a resin, and a claw, a boss, at least one of a hole and a sensor mounting member are integrally molded with a resin. 5. The method for fixing a sensor according to claim 1, wherein: 6. The sensor fixing method according to claim 1, wherein the sensor is a toner sensor.